AD VER TISEMENTS. Refrigerating and t r t t Ice Mea HASLAM5 the imers ZING MEAT, tence. Makers OT UMO tnuiuco, iuu iu tuuw B.H.P. The Haslam Foundry & Engineering Co. Ltd. (INCORPORATED WITH PONTIFEX & WOOD, Ltd.), UNION FOUNDRY, DERBY, And 175 to 177 SALISBURY HOUSE, LONDON, B.C. Telegraphic Address "ZERO, DERBY." Telephone No. 778 Derby. ABC and Bentley's Codes used. A D VER TISEMENTS. CARBONIC ANHYDRIDE & AMMONIA REFRIGERATING MACHINERY USED BY BRITISH & FOREIGN GOVERNMENTS, AND ALL LEADING STEAMSHIP COMPANIES THROUGHOUT THE WORLD. ALSO BY COLD STORAGE AND ICE-MAKING COMPANIES, MEAT FREEZING WORKS, BREWERIES, PUBLIC INSTITUTIONS, DAIRIES, &c. &c. Full information furnished by J. & E. HALL LTD., 10 St Swithin's Lane, London, E.C. And Dartford Ironworks, Kent. AD VER TISEMENTS. ANHYDROUS AMMONIA, LARGEST CONSUMERS IN THE UNITED KINGDOM. SUPPLIERS TO THE ADMIRALTY. MAXIMUM EFFICIENCY, MINIMUM COST, IMMEDIATE DELIVERY. Telegrams : ANHYDROUS, LONDON. Telephone No., 1729 AVENUE, (3 Lines.) REFRIGERATION, COLD STORAGE, AND ICE-MAKING WORKS BY THE SAME AUTHOR. Crown Svo, cloth. 3*. 6d. net. THE POCKET BOOK OF REFRIGERATION AND ICE-MAKING. Fifth Edition, Enlarged. 205 pages, with many Illustrations. "As a pocket book to users of refrigerating plant it is, of course, of the greatest possible value, having regard to its comprehensive character." The Marine Engineer. " It is a most useful companion for those engaged or interested in the rapidly growing industries connected with refrigeration and cold storage." Mechanical World. Demy 8v0, cloth. *]s. 6d. net. AERIAL OR WIRE-ROPE WAYS : Their Construction and Management. With Numerous Illustrations. "The book can safely be recommended as a useful general treatise on the subject." Civil Engineering. Medium Svo, cloth. 2$s. net. TEA MACHINERY AND TEA FACTORIES Describing the Mechanical Appliances required in the Cultivation and Preparation of Tea for the Market. London : CROSBY LOCKWOOD & SON, 7 Stationers' Hall Court, E.G., and I21a Victoria Street, Westminster, S.W. REFRIGERATION ii COLD STORAGE AND ICE-MAKING A PRACTICAL TREATISE ON THE ART AND SCIENCE OF REFRIGERATION WITH WHICH IS INCORPORATED "REFRIGERATING AND ICE-MAKING MACHINERY" (THIRD EDITION) BY A. J. )VALLIS-TAYLER, C.E. ASSOC. M. INST. C.E. AUTHOR OF "REFRIGERATING AND ICE-MAKING MACHINERY," "THE POCKET-BOOK OF REFRIGERATION AND ICE-MAKING," " SUGAR MACHINERY," " TEA MACHINERY," "BEARINGS AND LUBRICATION," "AERIAL OR WIRE ROPE TRAMWAYS," " MOTOR VEHICLES FOR BUSINESS PURPOSES," ETC., ETC. BDttion, tborougblg IRevfeefc WITH FOUR HUNDRED AND FOURTEEN ILLUSTRATIONS umert.V ' '* V LONDON CROSBY LOCKWOOD AND SON 7 STATIONERS' HALL COURT, LUDGATE HILL AND i2iA VICTORIA STREET, S.W. 1912 A. J. WALLIS^TAYLER, C.E, A.M.I.C.E., " ESQU1MALT/' ROBIN HOOD LANE, SUTTON, SURREY. Inspections, Surveys, Tests, Reports, Expert Evidence, Working and other Drawings, Technical Translations from or into French, *'- f"\ ?T f. f r *"< c^ - ;l ''. r: vj. o I ."/" '.!' ... ;. 'xC 'JlUv.^ /V: : ~.'^ PREFACE THE preservation of comestibles collected during times of plenty, for uses when the sources of supply fail, has been practised by man from the remotest ages and in the most uncivilised regions. Amongst primitive races, in order to avoid famine the preserva- tion of food for use during certain times of the year was absolutely essential, and in civilised countries it is a factor mainly responsible for the maintenance of the balance between the demand and the supply. Probably the most ancient method employed for the preserva- tion of food stuffs is desiccation or drying, and it is an excellent one, meat, for instance, so treated loses none of its nutritive qualities as it undergoes no chemical change. The remaining methods used are heating and sealing in air-tight packages, treatment by means of chemicals, and refrigeration. The conservation of meat and other food stuffs by the latter method, which is now so extensively used, is that with which the author is here solely concerned. By means of refrigeration or thermal control meat can now be transported round the world whilst retaining its original freshness. And fish, milk, butter, eggs, and fruits of almost every variety can also be preserved and transported in good condition. In fact, as stated in the Preface to the first edition of this book, refrigeration is a subject of great and daily increasing interest, and the field of usefulness of the art is continually widening. When the author produced, in 1895, his smaller work entitled " Eefrigerating and Ice-Making Machinery," the literature dealing specifically with the subject was of a very limited, and chiefly of a scattered description, but at the present time there are a number of books published, and the periodical literature has also been largely augmented. 274253 vi PREFACE. The success attained by "Refrigerating and Ice-Making Machinery" encouraged the production of the present larger volume, with the second edition of which was incorporatad the third edition of the above-mentioned smaller book. In this, the third edition of the larger volume, an additional chapter dealing with dairy refrigeration has been added, the introductory chapter has been partly re-written and brought up to date, as have also been those chapters dealing with examples of modern refrigerating machinery, marine refrigeration, manu- facturing industrial and constructional applications, ice-making, and the management and testing of refrigerating machinery. A large number of the illustrations contained in the previous editions have been replaced by blocks of more modern machines, and forty-six entirely new engravings have been added. The author takes this opportunity, moreover, of acknowledging the valuable assistance rendered by Mr G. J. Wells, W.Sc., A.M.I C.E., in revising the chapter devoted to the theory of refrigeration. Those requiring in a very concise form the primary details regarding ice-making and refrigerating machinery, cold storage, insulation, &c., will find their wants supplied by the fifth edition of "The Pocket Book of Refrigeration and Ice-Making," by the same author, and as this little volume comprises in addition to the above a very considerable number of important tables and other useful memoranda, conveniently arranged for immediate reference, it forms also a valuable companion to the larger book. A. J. WALLIS-TAYLER. SUTTON, December 1911. CONTENTS CHAPTER I. INTRODUCTION. PAOR Origin of Artificial Refrigeration History and Progress of the Trade in Fresh Provisions 1-7 CHAPTER II. THE THEORY AND PRACTICE OF MECHANICAL REFRIGERATION. Relation to First Two Laws of Thermo-dynamics Definition of Heat Specific Heat Latent Heat Mechanical Equivalent of Heat- Calculations made with respect to Heat Temperature Laws of Gases Construction of Chart Applicable to any Value of n Work Demanded of a Refrigerating Machine Greatest Theoretical Efficiency of a Refrigerating Machine 8-20 CHAPTER III. THE LIQUEFACTION PROCESS. Use of, by the Ancients Various Machines Operating on the Gene- ral Laws Governing Production of Cold by Principal Freezing Mixtures - 21-24 CHAPTER IV. THE VACUUM PROCESS. Principles of First Machine working on More Recent Types of Machines Working on - - 25-33 CHAPTER V. THE COMPRESSION PROCESS OR SYSTEM. Early History of Principles of Cycle of Operations Obligatory in Improvements in Ether Machines Sulphurous Acid Machines Carbonic Acid Machines - - 34-47 CHAPTER VI. THE COMPRESSION PROCESS (continued). Ammonia Machines Properties of Ammonia Cycle of Operations Wet and Dry Compression Principle Construction of Gas Com- pressors Various Examples of Modern Machines - - 48-116 viii CONTENTS. CHAPTER VII. THE COMPRESSION PROCESS (continued}. PAGES Properties of Ether Modern Ether Machines Properties of Methyl - Chloride Methyl-Chloride Machines Properties of Sulphurous Acid Sulphurous Acid Machines Properties of Carbonic Acid Carbonic Acid Machines - 117-151 CHAPTER VIII. CONDENSERS AND WATER COOLING AND SAVING APPARATUS. Submerged Condensers Amount of Cooling Water required Atmo- spheric or Open-air Evaporative Surface Condensers Amount of Condenser Surface required Amount of Cooling Water required Supplementary Condensers or Forecoolers Double-pipe Con- densers Hendrick's Condenser Water-cooling and Saving Appa- ratus Water-cooling Towers - 152-173 CHAPTER IX. THE ABSORPTION AND BINARY ABSORPTION PROCESS OR SYSTEM. The Principle of the Absorption Process Early Machines Later Pattems of Machines The Binary Absorption Process, or Machines Using a Compound or Dual Liquid - - 174-210 CHAPTER X. THE COLD-AIR SYSTEM. Principles of Early Machines Modern Patterns of Machines The Allen Dense-Air Ice Machine Maximum Theoretical Efficiency of Cold- Air Machines Comparative Tests of Cold- Air Machines - 211-245 CHAPTER XI. COCKS, VALVES, AND PIPE JOINTS AND UNIONS. Expansion or Regulating Cocks and Valves Stop-Cocks and Valves Suction and Discharge Valves Pipe Joints and Unions Means for Increasing the Cooling Surface of Pipes - 246-269 CHAPTER XII. REFRIGERATION AND COLD STORAGE. Refrigeration by means of the Cold-Air Machine Refrigeration by means of Compression or Absorption Machines The Brine Circula- tion System The Direct Expansion System The Cold-Air Blast System Piping for Cold Stores - - 270-284 CONTENTS. IX CHAPTER XIII. REFRIGERATION AND GOLD STORAGE (continued}. PAGES The Construction and Arrangement of Cold Stores and of Cold Storage Rooms or Chambers Ventilation Air Circulation Insulation Railway Vans - - 285-371 CHAPTER XIV. REFRIGERATION AND GOLD STORAGE (continued). Hoisting and Conveying Machinery - 372-380 CHAPTER XV. REFRIGERATION AND COLD STORAGE (continued). Proper Methods of Storing, and Temperatures for the Cold Storage of Various Articles Specific Heat and Composition of Victuals Meat and Fish Butter Cheese Milk Eggs Fruits Vege- tables Morgues or Mortuaries Table of Temperatures for Cold Storage of Various Articles - 381-395 CHAPTER XVI. MARINE REFRIGERATION. Carbonic Acid Machines Ammonia Machines Cold-Air Machines Arrangement of Cargo Holds and Stores Ice- making on Board Ship Barges - 396-421 CHAPTER XVII. REFRIGERATION IN DAIRIES. Methods of Using Mechanical Refrigeration in Dairies Examples of Mechanical Refrigerating Installations in Dairies Milk or Cream Coolers Ice-cooled Creamery Refrigerators Air Circulation System Cylinder System Insulation of Dairy or Creamery Refrigerators Sizes of Ice Chambers General Particulars Materials Ice Refrigerating Machine 422-438 CHAPTER XVIII. MANUFACTURING, INDUSTRIAL AND CONSTRUC- TIONAL APPLICATIONS. Chocolate Manufacture Breweries Paraffin Works Artificial Butter Manufactories Tea Factories Sugar Factories and Refineries Blast Furnaces Wine Making Various other Manufacturing and Industrial Applications Dynamite Factories Manufactories of Photographic Accessories Distilleries Chemical Works India- rubber Works Glue Works Constructional Applications : Tun- nelling, Sinking Shafts, Laying Foundations, &c. - - 439-483 x CONTENTS. CHAPTER XIX. ICE-MAKING. PAGES Various Methods of Ice-Making The Can System The Wall or Plate System The Stationary Cell System Miscellaneous Arrangements for Making Clear or Crystal Ice by Agitation Holden System of Ice-Making Water De-aerating or Distilling Apparatus Vacuum System of Ice-Making Imitation of Natural System Ice Factories Ice Elevating and Conveying Machinery Ice-Making, General Brine Storing Ice Ice-Crushing or Breaking Machinery - 484-538 CHAPTER XX. THE MANAGEMENT AND TESTING OF REFRI- GERATING MACHINERY, ETC. Management Ammonia Compression Machines Oil Separators or Collectors Accumulations of Deposit in the Condenser Breaking Joints Lubricating Qualities of Ammonia Compressor Piston- rod packings To Charge and Work a Carbonic Acid Machine Freezing or Choking up of Compression System Lubrication of Refrigerating Machinery Leaks in Ammonia Apparatus Leaks in Carbonic Acid Machines Effect of a Coating of Ice on Direct Ex- pansion Pipes Defrosting Refrigerating Coils Incrustation on Condenser Coils Cold-Air Machines Testing Interpretation of Compressor Diagrams Absorption Machines Amouut of Water required in Refrigerating Apparatus Determination of Moisture in Air Psychrometers Hygrometers Electrical Temperature Tell-tales and Long-distance Thermometers The Thermograph The Telethermometer or Electrical Thermometer Lighting Cold Stores - - 539-578 CHAPTER XXI. COST OF WORKING. Main Items of Expense Absorption Machines Compression Machines Vacuum Machines Cold-Air Machines Cost of Ice.Making - 579-587 CHAPTER XXII. THE PRODUCTION OF VERY LOW TEMPERATURES. Early Investigators and Experimenters The Cascade System The Regenerative Method Properties of Liquid Air Physical Con- stants of Liquefied Gases - - 588-601 APPENDIX. BIBLIOGRAPHY OF REFRIGERATION. Books-Periodicals - 602-604 INDEX - - - ...... 605-632 LIST OF ILLUSTRATIONS 1. Diagram showing Method of Constructing Curve PV* = C - 13 2. Diagram showing Method of Constructing Curve PV W =C ' . ' - 14 3. Diagram showing Method of Constructing Chart - - - 15 4. Carre's Sulphuric Acid Vacuum Freezing Machine 26 5. Lange's Exhaust Pump for Vacuum Freezing Machine 29 6. Harrison's Rotating Exhaust Pump or Cylinder 30 7. Perkins' Early Type of Compression Machine - 35 8.* Diagram Illustrating the Operation of a Refrigerating Machine on the Compression Principle - 37 9. Harrison's Ether Compression Machine 38 10. Tellier's Apparatus for the Distillation of Methylic Ether - - 41 11. Tellier's Methylic Ether Compression Machine - - 41 12. Expansion Valve or Distributor of Tellier's Methyllic Ether Machine 42 13. Original Type of Windhausen Compressor with Liquid Piston for Treating the Gas in Two Stages - 46 14. Suction Valve of Windhausen Compressor for Treating Gas in Two Stages 47 15. Outlet or Discharge Valve of Windhausen Compressor for Treating Gas in Two Stages - - - - - - 47 16. Diagram Illustrating Loss Due to Clearance Space in Compressor Cylinder - 54 17. Double-acting Vertical Type De La Vergne Ammonia Compressor. Vertical Section through Compression Cylinder - 58 18. Double-acting Vertical Type De La Vergne Ammonia Compressor. Side Elevation of Complete Machine - s 59 19. Diagrammatical View showing Complete Installation of a Refriger- ating Plant on the De La Vergne Ammonia Compression System 60 20. Diagram taken from Single-acting De La Vergne Ammonia Com- pressor without Sealing, Lubricating, and Cooling Fluid 62 21. Diagram taken from Single-acting De La Vergne Ammonia Com- pressor with Sealing, Lubricating, and Cooling Fluid - 63 22. Diagram taken from Double-acting De La Vergne Ammonia Com- pressor with Sealing, Lubricating, and Cooling Fluid - 64 23. Horizontal Type of Belt-driven Sterne Ammonia Compressor 65 24. Small Single-acting Vertical Type Frick Ammonia Compressor. Vertical Central Section through Cylinder - - 67 xii LIST OF ILLUSTRATIONS. FIG. PAGE 25. Large Single-acting Vertical Type Frick Ammonia Compressor. Vertical Central Section through Cylinder 68 26. Large Single-acting Vertical Type Frick Ammonia Compressor. Sectional Elevation of Complete Machine- 69 27-32. Diagrams taken from Frick Compressor - - 70 33. Enock's Patent Safety Compressor. Vertical Section - 72 34. Enock Safety Crossheads and Springs - - . 73 35. Enock Patent Compressor. Inclosed Type, with Coupled Vertical Steam Engine 74 36. 20-ton Open Type of Ammonia Compressor, Fitted with Enock's Patent Safety Crosshead - .75 37. Enock Inclosed Type 65-ton Compressor 77 38. Enock Self-oiling Midget Type Compressor - 78 39. Linde Horizontal Type of Compound Ammonia Compressor. Plan View 79 40. American Pattern Linde Horizontal Type of Ammonia Compressor. Part Sectional View " r ~_. 81 41. Horizontal Type of Belt-driven Humboldt Ammonia Compressor - 82 42. Two-Cylinder Single-acting Fixary Compressor 84 43. Double-acting Ammonia Compressor, Pulsometer Engineering Co., Ltd. 86 44. Small Single-acting Kilbourn Inclosed Type Ammonia Compressor and Condenser - 88 45. Double-acting Horizontal Type Triumph Ammonia Compressor. Sectional View - 89 46. Double-acting Horizontal Type Triumph Ammonia Compressor and Tandem Compound Condensing Engine. Plan View 90 47. Double-acting Puplett Ammonia Compression Machine 92 48. Horizontal Type Compound Haslam Ammonia Compressor. Vertical Central Section - ... 93 49. Horizontal Type of Haslam Double-acting Ammonia Compressor with Compound Drop-Valve Engine 95 50. Horizontal Type of Haslam Double-acting Ammonia Compressors with Compound Steam-Engine - - 96 51. Horizontal Compound Type of Haslam Ammonia Compressor with Compound ' ' Drop- Valve " Steam-engine - 98 52. Single-acting Vertical Type Ammonia Compressor, York Manu- facturing Co. Sectional Elevation of Complete Machine 100 53. Horizontal Type of Belt-driven Tuxen and Hammerich Ammonia Compressor - . . - , 101 54. Vertical Type of Steam-driven Buffalo Ammonia Compressor. Vertical Central Section through Cylinder - 103 55. Vertical Type of Steam-driven Hercules Ammonia Compressor. Vertical Central Section through Cylinder - 107 56. Double-acting Horizontal Type Barber Steam-driven Ammonia Com- pressor - 109 57. Double-acting Horizontal Type Barber Electrically-driven Ammonia Compressor - - 110 58. Small Single-acting Horizontal Type Barber Steam-driven Ammonia Compressor- . . . . . , - 111 LIST OF ILLUSTRATIONS. xiii FIG. PAGE 59. Double-acting Horizontal Type Vulcan Ammonia Compressor. Central Section through Cylinder - , 112 60. Small Single-acting Vertical Inclosed Type Vulcan Ammonia Com- pressor. Elevation partly in Vertical Section - ' - 113 61. Small Single-acting Vertical Inclosed Type Vulcan Ammonia Com- pressor. Transverse Section - 114 62. Belt-driven Horizontal Type West Ether Compression Machine - 118 6,3. Single-acting Inclosed Type Douane Methyl Chloride Compressor. Vertical Central Section - - 121 64. Belt-driven Double-acting Vertical Type Quiri Sulphurous Acid Compression Machine - 122 65. Belt-driven Double-acting Horizontal Type Quiri Sulphurous Acid Compressor - - 123 66. Belt-driven Horizontal Inclosed Type Douglas -Conroy Sulphurous Acid Compression Machine. Elevation partly in Vertical Section - - 125 67. Belt-driven Horizontal Inclosed Type Douglas-Conroy Sulphurous Acid Compression Machine. Plan of Compressor - 126 68. Belt-driven Horizontal Inclosed Type Douglas-Conroy Sulphurous Acid Compression Machine. Section on line A-B, Fig. 67 - 127 69. Belt-driven Horizontal Inclosed Type Douglas-Conroy Sulphurous Acid Compression Machine. Section on line C-D, Fig. 67 - 128 70. Vertical Type of Belt-driven Humboldt Sulphurous Acid Com- pression Machine - 130 71. Belt-driven Vertical Type Hall Carbonic Acid Compression Machine - - 131 72. Belt-driven Vertical Type Hall Carbonic Acid Compression Machine. Sectional View - '-132 73. Belt-driven Vertical Type Hall Carbonic Acid Compression Machine. Cross Section through Cylinder '- 133 74. Belt-driven Vertical Type Hall Carbonic Acid Compression Machine. Vertical Central Section through Cylinder - - 133 75. Belt-driven Vertical Type Hall Carbonic Acid Compression Machine. Vertical Section through Spiral Packing Ring . '- 134 76. Belt-driven Vertical Type Hall Carbonic Acid Compression Machine. Vertical Central Section through Suction Passage - 135 77. Belt-driven Vertical Type Hall Carbonic Acid Compression Machine. Vertical Central Section through Safety Valve - 135 78. Horizontal Type of Steam-driven Hall Carbonic Acid Compressor - 136 79. Horizontal Type of Duplex Steam-driven Hall Carbonic Acid Compressor - : - 137 80. Vertical Type of Belt-driven Hall Carbonic Acid Compressor. Most Recent Pattern - 139 81. Horizontal Type of Belt-driven Hall Carbonic Acid Compressor. Most Recent Pattern - 140 82. Vertical Type Steam-driven West Carbonic Acid Compression Machine - 141 83. Vertical Type West Carbonic Acid Compression Machine. Vertical Central Section through Compressor Cylinder - -142 xiv LIST OF ILLUSTRATIONS. FIG. PAGB 84. Vertical Type West Carbonic Acid Compression Machine. Vertical Central Section through Valve. Enlarged Scale - - 143 85. Vertical Type Belt-driven Kroeschell Carbonic Acid Compression Machine -.. 145 86. Horizontal Type Belt-driven Kroeschell Carbonic Acid Compressor - 147 87. Vertical Type of Belt-driven Humboldt Carbonic Acid Compressor - 148 88. Large Duplex Horizontal Type of Haslam Carbonic Acid Compressor 150 89. Chew's Patent Condenser, Submerged Type. Vertical Central Section - 153 90. Schou's Patent Condenser - 155 91. Diagram showing Simple Method of Distributing Water in Atmo- spheric Condenser - 158 92. Diagram showing Objections to Common Plan of Distributing Water in Atmospheric Condensers - 159 93. Diagram showing Method of Avoiding Spattering in Distributing Water in Atmospheric Condenser - 159 94. Arrangement for Removing Liquefied Agent from Atmospheric Condenser - 160 95. Haslam's Open-air Evaporative Surface Condenser 161 96. Haslam Interlaced Type of Ammonia Condenser - 162 97. Triumph Atmospheric or Open-air Evaporative Surface Condenser - 163 98. Rau's Atmospheric or Open-air Evaporative Surface Condenser - 163 99. 100. Westerlin-Campbell Double-pipe Condenser. Side and End Elevations - - 166 101. Haslam Double-pipe Ammonia Condenser / 167 102. Haslam Open Type of Water Cooler - 169 103. Puplett's Water Saving and Cooling Apparatus 170 104. Triumph Water-Cooling Tower. Elevation - - 171 105. Haslam Water-Cooling Tower - 172 106. Carre's Continuous-Acting Ammonia Absorption Machine - - 176 107. Pontifex-Wood Improved Continuous- Acting Ammonia Absorp- tion Machine - 188 108. 109. Pontifex-Wood Improved Ammonia Pump. Elevation and Vertical Central Section 189 110, 111. Hill's Ammonia Absorption Machine with Supplementary or Auxiliary Absorber. Diagrams showing Front and End Views - 195 112. Hill's Ammonia Absorption Machine with Supplementary or Auxiliary Absorber. Diagrammatical View of Complete Machine - - 196 113. Tyler & Ellis' (Cracknell's Patent) Ammonia Absorption Machine. Front View - - 198 114. Tyler & Ellis' (Cracknell's Patent) Ammonia Absorption Machine. Side Elevation - 199 115. Tyler & Ellis' (Cracknell's Patent) Ammonia Absorption Machine. Vertical Longitudinal Central Section . 199 116. Lyon's Patent Ammonia Absorption Machine. Plan - - 200 117. Lyon's Patent Ammonia Absorption Machine. Front Elevation - 201 118. Lyon's Patent Ammonia Absorption Machine. Vertical Longi- tudinal Section - - - - . - - 202 LIST OF ILLUSTRATIONS. xv FIG. PAGE 119. ISenssenbrenner Patent Ammonia Absorption Machine - - 203 120. Diagram Illustrating Coleman's Electrically-heated Absorption Machine - - 203 121. Diagram Illustrating Leading Type of American Ammonia Absorp- tion Machine - - 206 122. Diagram showing Paths of Ammonia, Cooling Water, and Ammonia Liquor through Various Members of Absorption System 207 123. Original Pattern Windhausen Cold-air Machine. Plan View - 217 124. Original Pattern Windhausen Cold-air Machine. Side Elevation - 218 125. Modified Form of Windhausen Cold-air Machine. Vertical Central Section - - . 220 126. Improved Type Giffard (1877) Cold- Air Machine. Sectional Side Elevation - ^ 223 127. Haslam Cold-air Machine. Horizontal Pattern . 226 128. Haslam Cold-air Machine. Diagonal Pattern- - 228 129. Haslam Cold-air Machine. Vertical Pattern - - 229 130. Lightfoot Double-acting Cold-air Machine, Horizontal Pattern. Vertical Central Section " - 232 131. Lightfoot Single-acting Cold-air Machine. Sectional Elevation - 233 132. Cole's "Arctic" Cold-air Machine with Auxiliary Cooling Arrange- ment. Sectional Elevation - 234 133. Cole's "Arctic" Cold-air Machine with Air-drying Arrangement. Small Size. Belt-driven Type - 235 134. Cole's "Arctic" Cold-air Machine with Air-drying Arrangement. Large Size. Steam-driven Type - - 236 135. 136. Cole's "Arctic" Cold-air Machine with Air-drying Arrange- ment. Side Elevation partly in Section and Transverse Section 237 137. Indicator Diagram from Double-acting Expander of Cole's " Arctic " Dry Cold-air Machine . - >. . 238 138. Indicator Diagram from Single-acting Expander of Cole's "Arctic" Dry Cold-air Machine - . 238 139. Allen Dense-air Ice Machine. Diagrammatical View 239 140. Taper Spindle Expansion or Regulating Valve. View partly in Vertical Section - -. 246 141. Taper Spindle Expansion or Regulating Valve. Vertical Central Section - 247 142. Triumph Angle Expansion or Regulating Valve. Vertical Central Section - 248 143. Triumph Globe Expansion or Regulating Valve. Vertical Central Section . - 248 144. Frick Angle Expansion or Regulating Valve. Vertical Central Section - 249 145. De La Vergne Expansion or Regulating Cock. Vertical Central Section - - - 250 146. De La Vergne Expansion or Regulating Cock. View of Plug partly in Section - - 250 147. De La Vergne Expansion or Regulating Cock. Plan - - 250 148. Triumph Safety Combination Expansion Valve and Stop-Cock. Vertical Central Section - - - - - 251 xvi LIST OF ILLUSTRATIONS. FIG. PAGE 149. Haslam Improved Type of Expansion Valve - - 251 150. De La Vergne 2^-in. Stop-cock. Vertical Central Section - 252 151. De La Vergne 1-in. Stop-cock. Vertical Central Section - 253 152. Frick Shut-off or Stop Valve. Vertical Central Section - - 254 153. 154. Frick Stop Valves. Perspective Views - - 254 155, 156. Haslam Standard Types of Ammonia Valves for Connections over 1 in. Diameter ^ - 255 157. Haslam Small Steel Valve for Gauge and other Connections under 1 in. Diameter - 255 158. Discharge Valve, Hercules Compressor. Vertical Central Section - 256 159. Suction Valve, Hercules Compressor. Vertical Central Section - 256 160. Triumph Suction Valve. Vertical Central Section - - 257 161. 162. Triumph Pattern Suction Valves for Frick Compressor. Vertical Central Sections - - 258 163, 164. Triumph Pattern Suction Valves for De La Vergne Compressor. Vertical Central Sections - - 258 165. Triumph Pattern Valve for Calahan Compressor. Vertical Central Section ; - 259 166. De La Vergne Pipe Joint. Perspective View - 261 167. De La Vergne Pipe Joint. Vertical Central Section - 262 168. Kilbourn Joint for Connecting Pipes to Plates. Vertical Central Section 263 169. Kilbourn Joint for Connecting Different Lengths of Pipe. Vertical Central Section through Joint - .,'-''* 264 170. Flange Coupling or Union for Lead Gasket. Vertical Central Section 265 171. 172. Frick Coupling or Union for Large Pipes. Vertical Central Section and End View - - 265 173. Frick Coupling or Union for Small Pipes. Vertical Central Section 266 174. Flange Coupling or Union for Sheet Packing. Elevation partly in Vertical Central Section 266 175. De La Vergne Soldered Pipe Joint, Bend or Elbow. Vertical Central Section - 266 176. Return Socket Bend. Vertical Central Section * 266 177. Flange Bend or Elbow. Vertical Central Section 266 178. 179. Frick Evaporating Coil Bend. Side View partly in Section and End View - - 267 180, 181. Flange Return Bend. End View and Side View - 267 182. Return Bend or Head Formed in Halves. Side Elevation - - 268 183. Return Bend or Head Formed in Halves. Vertical Central Section 268 184. 185. Discs or Gills for Increasing the Surface of Refrigerating Pipes. View showing Gill fixed on Pipe, and View showing One-half of Gill removed - 268 186. Diagram showing the Variation in Capacity, &c., of a Refrigerating Machine - - 277 187. Arrangement of Cooling Pipes in Refrigerating Chamber. Trans- verse Section - 289 188. Arrangement of Cooling Pipes in Ceiling Lofts. Transverse Sec- tion 290 LIST OF ILLUSTRATIONS. xvii FIG. PAGE 189. Hill's Arrangement for Refrigerating Cold Rooms or Chambers. Diagrammatical View - 290 190. Hill's Arrangement for Refrigerating Cold Rooms or Chambers. Elevation of Chamber partly in Vertical Section - - 291 191. Williamson's Patent Cold Storage Chamber - - 293 192. Haslam's Patent Brine-Cooling Battery, for Cooling Air to be Circulated through Cold Storage Rooms. Plan View - - 295 193. Douglas' Patent Apparatus for Cooling Air for Use in Cold Storage Rooms or Chambers. Vertical Central Section - - 296 194. Cooper's Apparatus for Washing, Cooling, and Drying Air for Use in Cold Storage Rooms or Chambers. Diagrammatical View - 298 195. Arrangement of Cooling Pipes in Beef Chill-rooms Fitted with the De La Vergne Patent Pipe System. Transverse Section - 299 196. Beef Chill-room in Cold Store Fitted with Haslain Patent Brine- Cooling Battery. Transverse Section - - 299 197. Refrigerating Installation on the Humboldt System Erected at Municipal Abattoir, Riga. Plan - 300 198. Refrigerating Installation on the Humboldt System Erected at Municipal Abattoir, Riga. Vertical Longitudinal Section - 301 199-201. Refrigerating Installation on the Humboldt System Erected at Municipal Abattoir, Riga. Transverse Sections - - 302 202. Hog Chill-room Fitted with the De La Vergne Patent Pipe System. Transverse Section - - 304 203. Arrangement of Cooling Pipes iru Chill-room and Curing Cellar in Bacon Factory. Transverse Section - 305 204. Small Cold Store for Butchers, &c., Cooled by Cold-air Machine. Plan View - - 307 205. Small Cold Store for Butchers, &c. , Cooled by Ammonia Compression Machine. Sectional Elevation - . 308 206. Small Cold Storage Room for Hotel or Private Residence. Vertical Section - 309 207. Cold Storage Rooms and Ice-Making Plant in Hotel. Perspective View - 310 208. 209. Rotating Air-Lock Door for Cold Storage Rooms in Hotels, &c. Sectional Elevation and Horizontal Section . 311 210. Diagram showing Gravity Air Circulation in Cold Storage Room or Chamber with Ceiling Piping - - 314 211. Diagram showing Gravity Air Circulation in Cold Storage Room or Chamber with Side Wall Piping - - 315 212. Diagram showing Gravity Air Circulation in Cold Storage Room or Chamber with Screened Wall Piping - - - 316 213. Diagram showing Gravity Air Circulation in Cold Storage Room or Chamber with Screened Wall Piping and Ceiling Extensions - 317 214. Diagram showing Gravity Air Circulation in Cold Storage Room or Chamber with Gay's Arrangement of Piping - - - 317 215. Diagram showing Gravity Air Circulation in Cold Storage Room or Chamber with St Glair Pipe Loft System- . - 318 216. Diagram showing Mechanical or Forced Air Circulation with Air Forced into the Room at Each End and Drawn Out at the Centre 320 b xviii LIST OF ILLUSTRATIONS. FIG. PAGE 217. Diagram showing Mechanical or Forced Air Circulation with False Ceiling for Distributing Cold Air from the Coil-room - - 321 218. Diagram showing Mechanical or Forced Air Circulation with Air Ad- mitted at Sides of Ceiling and Drawn Out at the Centre thereof 322 219. Diagram showing Mechanical or Forced Air Circulation with Air Admitted at One Side of Ceiling and Drawn Out at the Other Side - - 323 220. Diagram showing Mechanical or Forced Air Circulation with Air Admitted at Each Side of Floor and Drawn Out at Centre of Ceiling - 324 221. Diagram showing Mechanical or Forced Air Circulation with Air Admitted at One Side of Floor and Drawn Out at Other Side of Ceiling - 324 222. Diagram showing Mechanical or Forced Air Circulation with Air Admitted at Two Ducts on Each Side of Wall and Drawn Out through Perforated False Ceiling - - 325 223. Diagram showing Mechanical or Forced Air Circulation with Air Admitted at One Broad Duct ou Each Side Wall and Drawn Out through Perforated Ceiling - 327 224. Diagram showing Mechanical or Forced Air Circulation with Air Admitted through Perforated Floor and Drawn Out through Perforated Ceiling - - 328 223. Door for Cold Store with Taylor's Patent Fittings 357 226, 227. Frick Co. Method of Insulating a Cold Store. Vertical and Horizontal Sections - 358 228-235. Frick Co. Methods of Wall, Floor, Ceiling, Partition, Door, and Window Insulation- - 359 236. Frick Co. Method of Tank Insulation. Vertical Section - 361 237-246. Barber Manufacturing Co. Methods of Wall, Floor, Ceiling, and Tank Insulation - . . 362 247-254. Triumph Ice Machine Co. Methods of Wall, Floor, Ceiling, and Tank Insulation - . - 363 255-265. Triumph Ice Machine Co. Methods of Wall and Floor Insulation 364 266. Refrigerator Van or Waggon, Great Southern and Western Railway, Ireland. Sectional Side Elevation - 366 267. Refrigerator Van or Waggon, Great Southern and Western Railway, Ireland. End Elevation Partly in Section ] 367 268. Refrigerator Van or Waggon, Great Southern and Western Railway, Ireland. Sectional Plan - 368 269. Refrigerator Car or Waggon, Illinois Central Railway, U.S. Side Elevation Partly in Section - 369 270. Refrigerator Car or Waggon, Illinois Central Railway, U. S. Sectional Plan- .- 369 271-276. Childs' Patent Automatic Electrically-driven Beef Hoist- jjg 373 277. Childs' Patent Automatic Electrically-driven Beef Hoist. View showing a Quarter of Beef in Position - ; .- 375 278. Mutton Hoist in London Cold Store - 376 279. External Carcass Hoist at Nelson's Cold Storage Wharf, London. At Rest - - .- * - - - 377 LIST OF ILLUSTRATIONS. xix KIO. PAGE 280. External Carcass Hoist at Nelson's Cold Storage Wharf, London. At Work - - 379 281. Lawton's Apparatus for Preserving Fruit. Diagrammatical View - 390 282. Hall Horizontal Duplex Marine Type of Steam-driven Carbonic Acid Compression Machine - 399 283. Hall Vertical Marine Type of Steam-driven Carbonic Acid Compres- sion Machine 400 284. Hall Small Marine Type of Steam-driven Carbonic Acid Compression Machine. Vertical Central Section - 401 285. De La Vergne Vertical Single-acting Marine Type of Ammonia Compression Machine - 402 286. Puplett Horizontal Marine Type of Steam-driven Ammonia Com- pression Machine - - 403 287. Puplett Horizontal Marine Type of Belt-driven Ammonia Compres- sion Machine - 403 288. Haslam Vertical Self-Contained Marine T}-pe of Steam-driven Ammonia Compression Machine - - 404 289. Haslam Horizontal Marine Type of Steam-driven Compound Ammonia Compressor - 405 290. 291. Kilbourn Horizontal Self-contained Marine Type of Steam-driven Double-acting Ammonia Compressor. Plan and Elevation, partly in Section - 406 292. Kilbourn Horizontal Double-acting Marine Type of Belt-driven Ammonia Compressor - 407 293, 294. Marine Type of Ammonia Condenser. Plan and Elevation, partly in Section - - 408 295. Insulation of Cargo Holds on board S.S. "Campania" and "Lucania." Transverse Section - - - 409 296. Plan of Refrigerating Machine-room on Cunard Steamers - 410 297. Insulation of Provision Stores on board S.S. "Campania" and "Lucania." Transverse Section through Ceiling 412 298. Insulation of Provision Stores on board S.S. "Campania" and "Lucania." Vertical Longitudinal Section through Ceiling - 412 299. Enock Electrically-driven Ammonia Compression Machine, Marine Pattern - . 413 300. Hall Vertical Marine Type of Steam-driven Cold-air Machine - 414 301. Haslam Vertical Marine Type of Steam driven Cold-air Machine - 415 302. Haslam Vertical Marine Type of Steam-driven Cold-air Machine and Ice-making Apparatus - 416 303. Arrangement of Cold Storage Chamber on board Large Passenger Steamer. Sectional Plan - - 418 304. Ice-making or Congealing Tanks or Boxes for Use on Shipboard. Plan, Side, and End Elevations, and Detail View 419 305. Haslam Method of Sterilising the Cold Air for Use in Ships' Holds - 420 306. Complete Milk-Cooling Plant with Warm Milk Tank and Milk Pumps. Enock Ammonia Compression System - - 424 307. Installation on Ammonia Compression System in Dairy. Kilbourn System - - - - .,..,: - 426 xx LIST OF ILLUSTRATIONS. FIG. PAGE 308. Milk-Cooling Plant, Express Dairy Co., Ltd., London. Hall Carbonic Acid System . - 427 309. Installation for Milk Cooling on the Humboldt Sulphurous Acid System - 428 310. Sandbach Combined Cream Cooler and Heater. Plan . - 430 311. Sandbach Combined Cream Cooler and Heater. Elevation - ' 430 312. Capillary Cream Cooler. Elevation - - 431 313. Creamery Refrigerator on the Air Circulation System. Plan and Detail Views - 432 314. Creamery Refrigerator on the Air Circulation System. Section and Detail Views - 432 315. Creamery Refrigerator on the Cylinder System. Plan and Sec- tion - 434 316. Creamery Refrigerator on the Cylinder System. Detail Views - 434 317. Burnand Ice Refrigerating Machine for Dairies - 43(3 318. Burnand Small Ice Milk Cooling Apparatus - - 437 319. 320. Enock Patent Chocolate Cooler or Economiser. Sectional Elevation and Cross Section ? 441 321. " Baudelot Cooler " with Direct Expansion for Cooling Beer Wort - 446 322. " Baudelot Cooler" with Brine Circulation for Cooling Beer Wort - 447 323. Arrangement for Cooling Fermenting arid Yeast Rooms in Brewery on the Brine Circulation System - - 448 324. Arrangement for Cooling Fermenting Room on Direct Expansion Principle on the De La Vergne System - 449 325. Frick Co. Method of Cooling a Fermenting Room in Brewery. Transverse Section - - 450 326. 327. Arrangement for Suspending Flat Pipe Coils from Ceiling on the Iron Floor Beams. Side Elevation and Transverse Section - 451 328. Pipe Arrangement for Vault in Brewery. Transverse Section - 452 329, 330. Frick Co. Automatic Attemperator System and Cooling Arrange- ment. Side Elevation and Plan - - 453 331. Arrangement for Cooling Water for Attemperating Purposes in Breweries with Ammonia Absorption Machine - - 454 332. Triumph Ice Machine Co., Small Brewery with Refrigeratng Machinery Working on the Direct Expansion Principle. Sectional Elevation - - 458 333. Arrangement for the Extraction of Solid Paraffin from Shale Oil. Sectional Elevation- . 460 334. Refrigerating Arrangement in an Artificial Butter Factory. Sec- tional Elevation - - 462 335. Pontifex-Wood Brine Refrigerator - - 463 336. 337. Installation of Refrigerating Machinery (Haslam Type) for Desiccating 100,000 cubic feet of Air per Minute for use in Blast Furnaces. Perspective View and Plan View 467, 468 338. Gobert Congelation Method of Sinking Shafts. Vertical Section 478 339. Gobert Congelation Method of Sinking Shafts. Plan - 479 340-342. Gobert Congelation Method of Sinking Shafts. Details of Con- struction - 481 343. Pyramid Ice-making Box or Tank. Vertical Section - t -' - 487 LIST OF ILLUSTRATIONS. xxi FIG. PAQK 344- Box or Tank for Making Ice on the Can System - 488 345. "Eclipse" Can Ice-making Tank or Box. Vertical Longitudinal Section - 489 346. Propeller for Circulating or Agitating Brine in Ice-making Tank or Box. Side Elevation - 490 347. Frick Pattern Brine Strainer. Vertical Central Section 491 348. Arrangement of Freezing Tank on Can System showing Cause of Brine Foaming - - 492 349. Box or Tank for Making Ice on the Plate or Wall System - 493 350. Pontifex-Wood Cell Ice-making Tank or Box - - 498 351. Hill's Method of Making Clear or Crystal Ice. Plan of Box or Tank - 500 352. Method of Making Clear or Crystal Ice. Transverse Section on line x-x, Fig. 351 - - 500 353. Modified Arrangement of Hill's Method of Making Clear or Crystal Ice. Horizontal Section - - 501 354. Modified Arrangement of Hill's Method of Making Clear or Crystal Ice. Transverse Section on line x l -x l , Fig. 353 - - 501 355. 356. Haslam Patent Air Agitation Ice-making Plant. Sectional Elevation and Plan - 503 357. Oscillating Ice -making Tank or Box. Side Elevation - 504 358. Arrangement for Agitation of Water in Ice Cans by Means of Par- tially Submerged Double -ported Plunger Pump. Sectional Elevation - 504 359. Arrangement for Agitation of Water in Fixed Ice Cans by Means of a Plunger or Piston Pump. Vertical Longitudinal Section - 505 360. Arrangement for Agitation of Water in Removable Ice Cans or Moulds by Means of Plunger Pumps. Transverse Section - 506 361. Arrangement for Agitation of Water to be Frozen in Ice-making Tank or Box by Long Horizontal Agitator. Transverse Sec- tion - - - 506 362. Arrangement for Agitation of Water to be Frozen in Ice-making Tank or Box by Means of Vertical Plunger Pump. Transverse Section 507 363. Arrangement for Agitation of Water to be Frozen in Ice-making Tank or Box by Means of Horizontal Plunger Pump. Transverse Section - 507 364. Triumph Ice Machine Co. Oil Separator and Condensed Water-cooler. Plan - - 509 365. Triumph Ice Machine Co. Oil Separator and Condensed Water-cooler. Vertical Section - 509 366. Frick Co. Apparatus for Making Distilled Water from Exhaust Steam. Diagrammatical View - 510 367. Diagram Illustrating Operation of Triple-effect Evaporating Ap- paratus - 511 368. Complete Single- effect Distilling Apparatus on the Yaryan System - 513 369. Complete Sextuple -effect Distilling Apparatus on the Yaryan System - - - . - 515 xxii LIST OF ILLUSTRATIONS. FIG. 1-AOK 370. Ice-Tank or Box-room of Ice Factory on the Can System. Sectional Elevation - - 519 371. Ice-Tank or Box-room of Ice Factory on Plate or Wall System, showing Mechanism for Raising Slabs or Blocks of Ice - - 520 372-374. Frick Co. Plan for Ice Factory of 6 to 10 Tons Capacity. Plan, Sectional Side Elevation, and Transverse Section .-. 521 375 377. Frick Co. Plan for Ice Factory of 30 to 35 Tons Capacity. Sec- tional Side and End Elevations, and Plan - - 522 378-380. Frick Co. Plan for Ice Factory of 100 Tons Capacity. Plan and Sectional Side and End Elevations 523 381, 382. Arrangement of Model Ice Factory by the Triumph Ice Machine Co. Plan and Sectional Elevation " 524 383, 384. Vulcan Iron Works Arrangement for a 5-ton Ice Factory 011 the Can System. Plan and Sectional Elevation - 525 385. Ice Factory on the " Eclipse" Can System, Constructed by the Frick Company. Sectional Elevation - - 52& 386. Frick Ice-Can Hoist for Use with Small Ice-making Plants - 527 387. Travelling Crane and Geared Hand-power Ice-Can Hoist - 528 388. Electric Crane for Handling Ice Cans in Large Factories - - 528 389. Automatic Ice Dump 529 390. Vulcan Iron Works Track System 529 391. Brine Mixing Tank. Vertical Longitudinal Central Section - 533 392. Haslam Brine Concentrator - 534 393. 15-ton per Hour Power Ice-crushing Machine - - 538 394. Voorhees Oil Separator or Collector. Vertical Central Section 546 395. Yaryan Form of Oil Separator, Collector, or Interceptor. Vertical Central Section - - 54& 396. Triumph Ice Machine Co. Ammonia Receiver and Oil Trap. Vertical Central Section and Detail Views - - 550 397. Stuffing Box and Packing for Ammonia Machines. Longitudinal Section - 553 398. Mercury Well for Horizontal Pipe. Vertical Section - 563 399. 400. Mercury Well for Vertical Pipe. Vertical and Horizontal Sections - 563 401. Diagram from Compressor in Good Order 567 402. Diagram from Compressor Indicating an Excessive Amount of Clearance - - 567 403. Diagram from Compressor Indicating Binding of Pressure Valve - 567 404. Diagram from Compressor Indicating Too Great a Resistance in Pressure and Suction Pipes - 567 405. Diagram from Compressor Indicating Binding of Suction Valve - 568 406. Diagram from Compressor Indicating Leaking of Compressor Valve - 568 407. Diagram from Compressor Indicating Defective Packing of Piston 568 408. Diagram Illustrating Arrangement of Electric Lighting on the Series Circuit System 577 409. Diagram Illustrating Arrangement of Electric Lighting on the Parallel Circuit System - 577 410. Diagram Illustrating the Cascade or Successive Cycle System of Producing Very Low Temperatures - 589 LIST OF ILLUSTRATIONS. xxiii FIG. PAGB 411. Diagram Illustrating Tripler's Apparatus for the Production of Very Low Temperatures by the Regenerative Method - - 594 412, 413. Hampson's Apparatus for the Production of Very Low Tempera- tures by the Regenerative Method. Vertical and Horizontal Sections - - 596 414. Linde's Apparatus for the Production of Very Low Temperatures by the Regenerative Process. Sectional Elevation - - 597 ERRATA. Pages 130 and 148. The descriptions of the illustrations in both cases should read "Hori- zontal Type " instead of " Vertical Type." of the water congealed more palatable and sanitary than the natural product ; to its extensive use for the freezing and chilling of freshly killed meat in abattoirs ; and to its application to the cooling of stores or chambers for the preservation of meat, fowl, fish, butter, cheese, fruit, vegetables, and other provisions of a perishable nature : mechanical refrigeration is now commonly employed in a number of different manu- facturing processes, brief descriptions of the most important of which applications will be found in a chapter devoted to this subject. The trade in fresh provisions is one that during the last few years has made enormous strides, and at the present time vast quantities of frozen carcasses, and of fish, fruit, vegetables, butter, cheese, and milk are being imported into this country. REFRIGERATION, COLD STORAGE, AND ICE-MAKING CHAPTER I INTRODUCTION Origin of Artificial Refrigeration History and Progress of the Trade in Fresh Provisions. ALTHOUGH refrigeration and the production of ice by artificial means is said to have been known to, and practised by, the Ancients, it is only in comparatively recent times that improved systems and apparatus have enabled operations to be carried out profitably on a commercial scale, and have rendered possible the numerous manufacturing and industrial applications now made. In addition to the employment of mechanical refrigeration for the manufacture of ice, more durable, and by reason of the known purity of the water congealed more palatable and sanitary than the natural product ; to its extensive use for the freezing and chilling of freshly killed meat in abattoirs ; and to its application to the cooling of stores or chambers for the preservation of meat, fowl, fish, butter, cheese, fruit, vegetables, and other provisions of a perishable nature : mechanical refrigeration is now commonly employed in a number of different manu- facturing processes, brief descriptions of the most important of which applications will be found in a chapter devoted to this subject. The trade in fresh provisions is one that during the last few years has made enormous strides, and at the present time vast quantities of frozen carcasses, and of fish, fruit, vegetables, butter, cheese, and milk are being imported into this country. - 4*1 2 REFRIGERATION AND COLD STORAGE. Space does not, unfortunately, admit of entering into any lengthy account of the history of this trade, which is one of great interest, or of giving lengthy statistics relative to the constantly increasing amounts of these imports ; the full figures can, however, readily be got from a variety of sources by anyone interested therein, and, moreover, they hardly come within the province of a book purporting to be devoted to a description of the various machines and appliances adapted for refrigeration and ice-making. The following, however, are a few of the leading facts and figures : Meat frozen by a Harrison ether machine was shipped from Mel- bourne on the 23rd July 1873, and arrived here on the 18th October, but turned out a failure. In 1875 and 1876 frozen meat was brought over from America. The first cargo of frozen meat was successfully brought to this country from Australia in the year 1880, in the " Strathleven," which is said to have been fitted with a Bell-Coleman cold-air machine, and this was quickly followed by another consignment in the "Protos," refrigerated by means of a cold-air machine of the Lightfoot pattern. On 5th October of the same year the steamship " Orient " arrived at London with a cargo of frozen meat, she being also fitted with refrigerating apparatus on the cold-air principle, in this instance one of Haslam's patent dry-air refrigerators being employed, which worked without interruption during the entire voyage of six weeks' duration. On the 26th September, in the succeeding year, the clipper ship " Mataura," also fitted with a Haslam patent cold-air machine, arrived with a cargo of frozen meat from New Zealand. Such were the commencements of the trade in refrigerated meat, and it has so rapidly advanced that, in mutton and lamb alone, from 400 carcasses in 1880, it has risen to 12,981,044 carcasses in 1910. According to Messrs Weddel & Co.'s annual report, the total receipts of frozen mutton for 1910 was 7,552,977 carcasses, as compared with 5,915,455 in 1909. These figures represent an increase of 1,637,522 carcasses, or 2 7 '7 per cent. These developments in mutton syn- chronised with a small extension in the imports of lamb, which aggregated 5,428,067 carcasses, as compared with 5,151,697 carcasses in 1909. Taking mutton and lamb together, the aggregate of the importations was 12,981,044 carcasses, as compared with 11,067,152 in 1909, and is the highest hitherto recorded. The following tables compiled from statistics published by Messrs W. Weddel & Co. show, in the first, the growth of the trade in frozen mutton and lamb, from the commencement of the trade in 1880 to 1890; and in the second (page 4), from 1891 to 1910. INTRODUCTION. YEARLY IMPORTS OP FROZEN MUTTON AND LAMB FROM COMMENCE- MENT OF THE TRADE TO 31sT DECEMBER 1890. Year. Australia. New Zealand. Falkland Islands. River Plate. Totals. 1880 400 400 1881 17,275 ... 17,275 1882 57,256 8,839 ... 66,095 1883 63,733 120,893 ... 17,163 201,789 1884 111,745 412,349 ... 108,823 632,917 1885 95,051 492,269 190,571 777,891 1886 66,960 655,888 30,000 434,699 1,187,547 1887 88,811 766,417 45,552 641,866 1,542,646 1888 112,214 939,231 924,003 1,975,448 1889 86,547 1,068,286 1,009,936 2,164,769 1890 207,984 1,533,393 10,'i'68 1,195,531 2,947,076 The steady increase in the amounts of frozen and chilled beef imported into this country for the period of twenty years, viz., from 1891 to 1910, is no less phenomenal than that of mutton and lamb. In 1891 the total imports, as will be seen from the table on page 5, also compiled from Messrs W. Weddel's statistics, amounted to 1,157,854 cwt., whilst in 1910 the figures reached 4,246,182 cwt. Three shipments of chilled beef were made during 1910 from Australia, the condition of one of which was imperfect owing to the use of unsatisfactory meat wraps. It has, however, been definitely proved that, aided by the Linley process, chilled beef can be brought from Australia or New Zealand to this market, and delivered, after a seventy days' voyage, in good condition. The trade in frozen rabbits has also attained to considerable dimensions, and as far back as 1900, 36,823 crates, containing 917,142 rabbits, were sent to this country from South Australia. In 1886 the steamship "Nonpareil" (Scrutton, Sons, & Co.), which had been fitted for the purpose with a Haslam dry-air refrigerator, brought to this country the first cargo of West Indian fruit ; and early in 1888 a cargo of apples was shipped from Melbourne in the " Oceana," in chambers also cooled by a Haslam machine, both cargoes arriving in good condition. Subsequently many of the ships belonging to the Peninsular and Oriental Steamship Company, and others, were fitted up for this trade, and Messrs Elder, Dempster, & Co. inaugurated the Imperial West India Direct Mail Service, the steamers of which line are specially adapted for the transport of large quantities of bananas from Jamaica, a task which has been successfully performed. The i; o o S H 3i 00 Ol QC O CO """* O QC *-O IT^* 00 *O *O CO OS fH'-HC i-t (M CO ^H O O5 ^HOOOt^ O5 tr^ >H CO iO CO i< os x i i 01 co c r-ntM- i-*ir: A N oSt^SSjoS^t^^cocooocooiiocooSi-i OS CO ' i r>-O i 1 CO l> < b co co DOOCO^OSiOCDGOO tOSOCO-HOCOOS-<^ cT o~ 10" co" cT cc" oT cT ~* oT cT o" co" o" co" oo" TJ^ co" c4" -^ COCOOO(MCOOOOOS-HC k lCO^HTtiCOCOTtllC^t l OOlO ,-T r-* ,-T i-T r-T i-T of of tf of of of oT T c (N'cO~CO~CO~CO' 1 CO~ T*T T3 _^ _^ _^ _^ _, _, _^ __ _^ _ B - ,, v v w ^ -,-- S oTi-T-<*'icroio"o~r-rTf"o'co" > oo"oo' s coi-HOoocot^O5 r -^t^C5COCiTt < PQ 1 .g g _ go 888808e888eog , ^ * _^ ToTp Tco ""5 e3 O 1 _a3Ert. (U *t~-OiCOO5T^"*ooOCO>OCMQO r^ EL ICOCOCOt^-OSCOCO^CO'^'TfOOOO-l 2 ^ .3 3 SOiO5OiOiO5OiO5OiOiOOOOOOOOOO^^ M 00 00 00 00 00 00 00 00 00 O5 O5 O5 O5 O5 OS Oi OS O5 O5 Oi ^3 ^ ^ fe _ _ _ Tt^ Op rH Op CO CO OO t CO CO O^l CO Oi a5 J - 9'^^^55'Si>ai - r H '>^ y i ort-r^ ^r-tTtt 1 ^ i22^! I-H CO OO * F *O ~ "tn > ~ H W C/5 h ^ O O 00 ^ ~* 00 CO Ol CO IO "^ CO OQ O5 r ) 00 O^ ^O OO t~~ ^ >S CO^Ot^OOCOCOCOOOOOOOOOCOr-HO"*TtO, is a colourless liquid of great mobility, and possessed CHJ 25 of a strong and peculiar ethereal smell. Ether is lighter than water, having a specific gravity 0-736, and it is not miscible with the latter liquid. The boiling point of ether is 34-5, and its vapour is thirty- seven times heavier than hydrogen. Ether burns with a luminous flame, and explodes when it is mixed with air. The specific heat of liquid ether is 0'51. The advantages and disadvantages of ether as an agent or medium have already been touched upon (pages 43 and 44), but they may be here recapitulated. The great feature of ether is that it possesses the quality of working with a low pressure in the condenser, an advantage of considerable importance in very warm climates, as the efficiency of a low-pressure ether machine does not fall off appreciably, even when the condensing water attains to a comparatively high temperature. This is also advantageous by reason of the low condenser pressure not exceeding from 7 to 10 Ibs. per square inch, even in the hottest climates being favourable to the maintenance of tight joints, and the consequent economy of the chemicals. This low working pressure and the great simplicity of all the working parts renders this class of machine, moreover, comparatively easy to manage. On the other hand, the large size of the compressor required, about seventeen times that of an ammonia compressor of the same capacity, is objectionable, both by reason of first cost of the machine and the space occupied by it. Another serious objection is the highly inflam- mable nature of ether. Owing to its low boiling point great precautions 117 n8 REFRIGERATION AND GOLD STORAGE. are necessary to avoid explosions when using this substance, by reason of the vapour becoming mixed with air. All formula and rules intended for use with ammonia compressors are equally applicable to ether compressors, except, however, that it must be noted that the specific heat of the saturated vapour of ether is positive, and that consequently it will superheat during expansion, and will condense during compression. This quality renders it un- Fig. 62. Belt-driven Horizontal Type West Ether Compression Machine. necessary to make any provision against superheating, and an ether compressor is invariably worked with dry vapour. The ether machines of Twining, Harrison, Tellier, Siebe Gorman & Co., and Delia Beffa, have been already briefly alluded to on pages 37 to 42. In Fig. 62 is illustrated a modern standard type of ether machine constructed by H. J. West & Co., Ltd., London, which the company now supply for use in tropical countries. A commercially successful ether compression machine for the manufacture of ice THE COMPRESSION PROCESS OR SYSTEM. 119 in large quantities was built by Mr Henry J. West, the founder of this firm, in the year 1859, and the manufacture of machines of this type has been continued successfully up to the present day. The machine shown in the illustration (which is intended to be belt-driven) is of the horizontal type, and is arranged with the condenser on one side, and an ice-making tank upon the other. In the larger pattern of ether machines made by the firm, having a capacity of from 12 cwt. of ice daily and upwards, the ether com- pressor is placed on the same bed- plate as the steam engine, and is connected tandemwise to the engine piston rod. The motion work of these machines is of sufficiently massive construction, and all wearing surfaces are of ample proportions, each bearing, moreover, being provided with an automatic lubricator. An ether compression machine not being called upon to withstand the same high pressures as a carbonic acid machine, or even an ammonia machine (the working pressure of an ether machine being only about 7 Ibs. to 10 Ibs. per square inch above that of the atmosphere), the same strength of construction is not demanded, and the design is very considerably simplified. The difficulty of making and maintaining tight joints is a comparatively easy matter, the pressure under which ether evaporates in the refrigerator being lower than that of the external atmosphere, but a very slight tendency exists towards leakage at the gland of an ether compressor. Any leakage, moreover, of air that may occur into the ether machine through faulty packing or joints, merely causes a slight accumulation of pressure in the condenser, which can be easily relieved by means of a valve provided for the purpose. As ether possesses no affinity for the constituents of the atmosphere, there is consequently no danger of decomposition taking place, and the formation of acids or gases that may act injuriously on the interior surfaces of the machine, as is the case with sulphurous acid, which, under like conditions, decomposes and forms sulphuric acid. A quality possessed by ether is that it is in a liquid state at the ordinary atmospheric pressure, and at the usual atmospheric tempera- tures, so that it can be drawn out of . the plant at any time and stored in drums. This fact renders ether an especially suitable agent or medium for use in portable refrigerating and ice-making plants, con- sequently, machines working on the low-pressure ether anhydride process are those most usually chosen for military purposes, and such machines were successfully used by the British Government for military operations and field hospital work in the Abyssinian War in 1868, the 120 REFRIGERATION, AND COLD STORAGE. Ashantee Campaign in 1874, the military operations in Egypt in 1883, the Ashantee Campaign of 1895, the Soudan Campaign of 1896-97, and the last protracted and unfortunate war in South Africa. PROPERTIES OP METHYL CHLORIDE, AND METHYL CHLORIDE MACHINES. Another very low-pressure agent or medium is methyl chloride (CH 3 C1), which is obtained as a colourless gas which condenses at -20 Fahr. Methyl chloride is formed by acting upon methyl alcohol with hydrochloric or muriatic acid, or with phosphorus pentachloride, and is also obtained, together with other substances, by the action of chlorine upon marsh gas. Machines operating with methyl chloride as an agent are manu- factured by Messrs Douane, of Paris. As the pressure used with this agent does not exceed 10 Ibs. per square inch above that of the atmosphere, the same remarks apply to methyl chloride compressors as to ether compressors, and the construction is practically identical. The condenser and evaporator tubes of the methyl chloride machines made by Messrs Douane are all covered with electro-deposited copper. In Fig. 63 is illustrated in vertical central section a compression machine, designed by Mr M. E. Douane. In this machine the cooler or refrigerator is shown on the left-hand side of the drawing. There is a hollow standard surmounted by a single-acting cylinder, the top of which has valves for suction and discharge. The space above the discharge valve communicates with a coil leading by a tube to the stop- cock serving for the admission of the refrigerating liquid in the cooler. The chamber underneath the suction valve communicates by a pipe with the outlet of vapour from the cooler. A gauge screwed upon a nozzle shows the pressure in the cooler. The piston of the compressor is worked by a rod and crankshaft which passes through a stuffing box in the side of the hollow standard. PROPERTIES OF SULPHUROUS ACID, AND SULPHUROUS ACID MACHINES. Sulphurous acid or sulphur dioxide (SO 2 ) is a gas obtained by the burning of sulphur, as has been already mentioned on page 44. Sulphurous acid has a molecular weight of 65, and a density of 32. The specific heat of liquid sulphurous acid is '41 (water =1). The critical pressure is 79 atmospheres, and the critical temperature 312 Fahr. The specific gravity of the gaseous acid is 2-211 (air = l), and the specific gravity of the liquid at a temperature of -4 Fahr. is 1'491. THE COMPRESSION PROCESS OR SYSTEM. 121 Andreef gives the following formula for expressing the relation of the specific gravity s of the liquid to the temperature t : a = 1-4333 - 0-00277(5 - 0-000000271* 2 . Sulphurous acid or sulphur dioxide possesses the advantage of being liquefiable at a comparatively low temperature, and machines adapted to use this agent or medium, whilst not operating at anything like as low a pressure as ether or methyl chloride machines, still work at a very much lower one than ammonia machines, with condensing water Fig. 63. Single- Acting Inclosed Type Douane Methyl Chloride Compressor. Vertical Central Section. at normal temperature, the pressure being only from about 36 '75 to 44 Ibs. per square inch. Sulphur dioxide possesses certain lubricating qualities, consequently compressors using this agent require no extra lubrication. Sulphur dioxide is liable to form sulphuric acid on exposure to the air, and cause corrosion iron being the metal chiefly acted upon, and gun-metal or copper being tolerably immune against attack. Conse- quently it is necessary to take great precautions against the presence of any leaky joints in the apparatus. 122 REFRIGERATION AND COLD STORAGE. This comparatively low working pressure, and consequent corre- spondingly low temperature of compression, admits of machines using Fig. 64. Belt-driven Double- Acting Vertical Type Quiri Sulphurous Acid Compression Machine. this agent working without superheating, and with dry vapour. This latter is not practicable in the case of machines working with either THE COMPRESSION PROCESS OR SYSTEM. 123 ammonia or carbonic acid, in both of which superheating is impossible especially so in the case of carbonic acid on account of the overheat- ing of the piston and stuffing box that would occur, and consequently all these latter machines work more or less on the wet system, and a small portion of the work of evaporation, which ought to take place in the refrigerator exclusively, has to be effected in the compressor. A number of different patterns of machines adapted to work with sulphur dioxide are made by Quiri & Co., Schiltigheim, Alsace. The smallest type of machine made by this firm, which is shown in Fig. Fig. 65. Belt-driven Double- Acting Horizontal Type Quiri Sulphurous Acid Compressor. 64, has a vertical compressor, the cylinder being bolted to the lower head which is formed in one piece with the guides, the latter, as well as the crankshaft journals, being cast together with the condenser. The compressor is of the double-acting type, and is provided with valves of phosphor bronze, with steel spindles. These machines are made in sizes of from 4| cwt. to 12 cwt. ice-making capacity per twenty-four hours. The larger sizes of machines are of the double-acting horizontal pattern, and are arranged either for belt or rope drive, or are direct coupled to a steam engine. 124 REFRIGERATION AND COLD STORAGE. The belt-driven compressors consist either of a single cylinder double acting pump, such as that shown in Fig. 65, which is of re- markably simple construction, or of two practically similar pumps, laterally coupled, that is to say, arranged side by side, and having a single crankshaft with two end cranks, and a central fly-wheel between the two compressors adapted for a rope drive. In another arrangement, intended for rope driving, two similar com- pressors are mounted in line upon the ends of a single bed plate. Both the piston rods of the compressor cylinders are in this case coupled through their connecting rods to the same crankpin upon a crank at the end of a crankshaft supported in a bearing upon the bed-plate, and in an outside bearing in a suitable pedestal. Upon this crankshaft is a fly-wheel, grooved for rope driving. This machine may be coupled to a Sulzer steam engine. One pattern of steam-driven compressor consists of a compressor practically similar to that shown in Fig. 58, laterally coupled to a steam engine with slide valve motion, in a similar manner to the two pumps above mentioned. These anhydrous sulphuric acid compressors are each connected with a condenser, either of the submerged or immersion type, or, in cases where condensing water is scarce, with a condenser of the atmospheric evaporative type, and with a refrigerator, and the entire refrigerating apparatus consists of these parts solely, no oil-pumps, oil-separators, rectifying apparatus, or other accessories, such as are required with ammonia and carbonic acid machines, being necessary. This fact obviously enables anhydrous sulphuric acid machines to be very much simplified in construction, and renders their successful working a far easier matter to accomplish, as the manipulation of the above apparati is troublesome, and to an unskilled attendant presents many serious difficulties. This system is one, therefore, which should most undoubtedly be advantageous for small machines intended for use in hotels, creameries, dairies, and in private houses, and by butchers, fishmongers, &c., and in other places where the machine is left to the care of a comparatively unskilled person. A very small and remarkably compact belt-driven anhydrous sulphur dioxide or sulphurous acid machine, designed and patented by Messrs Douglas & Conroy, and manufactured by W. Douglas & Sons, Ltd., Putney, London, S.W., is shown in Figs. 66 to 69. Instead of the compressor being mounted vertically upon the side of the condenser, as it is in the small machine previously described, it is, it will be seen, placed horizontally upon the top of the condenser, and is of the THE COMPRESSION PROCESS OR SYSTEM. 125 inclosed type, consisting of two single-acting horizontal cylinders, arranged in line, the pistons being operated by a crank working in a box. The arrangement will be readily understood from the general view of the apparatus shown in Fig. 66, upon which for convenience the various parts are marked, and from the various other views, Fig. 67 Fig. 66. Belt-driven Horizontal Inclosed Type Douglas -Conroy Sulphurous Acid Compression Machine. Elevation partly in Vertical Section. being a plan of the compressor, Fig. 68 a vertical section on the line A-B, Fig. 67, and Fig. 69 being a vertical section on the line C-D, Fig. 67. The compressor is of the single-acting duplex inclosed type, and consists of two cylinders arranged in the same line axially, united by a central casing forming the crank chamber, and mounted on a bracket 126 REFRIGERATION AND COLD STORAGE. on one side of the upper part of the condenser. The sides of the chamber are closed by gas-tight covers in one of which is provided a stuffing box and gland through which passes the crankshaft. The outer portion of the crankshaft is supported in a bearing in a pedestal carried upon another bracket provided upon the opposite side of the upper part of the condenser, and this shaft has mounted upon its outer end the fast and loose driving pulleys, and on the inner end, within the central crank box or chamber, a disc crank. Fig. 67. Belt-driven Horizontal Inclosed Type Douglas -Conroy Sulphurous Acid Compression Machine. Plan of Compressor. The two pistons working in the pump cylinders are rigidly fastened together by means of a rectangular frame or plate secured between them by bolts. The result of this arrangement is that the pistons act as a continuous guide, being entirely free from lateral thrusts, and the usual guides are thus dispensed with, thereby considerably simpli- fying the construction. The pin of the crank disc works in a slot provided in the central rectangular frame or plate connecting the pistons. This admits of a pause at the end of each stroke, which is THE COMPRESSION PROCESS OR SYSTEM. 127 advantageous inasmuch as it gives the valves time to reseat themselves properly before the commencement of the return stroke. Four valves are provided, two at each extremity of the duplex- pump cylinders, viz., one for compression and the other for suction, and each pair of similar valves is united into one pipe by means of a Fig. 68. Belt-driven Horizontal Inclosed Type Douglas- Con roy Sulphurous Acid Compression Machine. Section on line A-B, Fig. 67. tee connecting piece. The central crank box or chamber is kept partially full of oil, so that the working parts are immersed in an oil bath and have the most perfect lubrication. The condenser consists of a cast-iron tank and serves as a pedestal to support the compressor. In this tank is placed a coil of wrought- 128 REFRIGERATION AND COLD STORAGE. iron pipe tested to a pressure of 500 Ibs. per square inch, and welded into one piece without joints, in which coil the sulphurous acid gas is liquefied by the pressure from the compressor aided by the cold water circulating in the tank. Fig. 69. Belt-driven Horizontal Inclosed Type Douglas -Conroy Sulphurous Acid Compression Machine. Section on line c-D, Fig. 67. The evaporator or refrigerator consists of a suitable tank having a coil submerged in brine, and when the machine is used in connection with a cold room or store this evaporator tank is formed of galvanised iron and of rectangular shape, and is placed directly in the room or store to be cooled. THE COMPRESSION PROCESS OR SYSTEM. 129 Fig. 70 shows a horizontal type of belt-driven Humboldt sulphurous acid or sulphur dioxide compression machine. A feature of this machine is that the cylinder is jacketed, no cooling of the piston rod being provided. The general design of the machine, which is made by the British Humboldt Engineering Co., Ltd., London, will be seen from the illustration. Amongst other firms manufacturing sulphurous anhydride com- pression machines mention may be made of the following : A. Borsig, Tegel, bei Berlin, Germany ; The Raoul Pictet Company, of Paris ; Delion & Lepen of Pre St Gervais, Paris ; the Societe Genevoise de Construction, of Geneva; and Thomas Ths. Sabroe & Co., Ltd., Aarhus, Denmark. PROPERTIES OF CARBONIC ACID, AND CARBONIC ACID MACHINES. Carbon dioxide, or, as it is commonly called, carbonic acid (CO 2 ), has a molecular weight of 44, and a density of 22. Carbon dioxide is invariably formed when carbon is burned in an excess of air or oxygen. The best method of preparation is by acting upon marble, chalk, or other form of calcium carbonate with hydrochloric or muriatic acid. Carbon dioxide occurs free in air, and in the water of some mineral springs, the quantity of the gas present in air being about 4 volumes per 10,000 volumes of air. As carbon dioxide is evolved in respira- tion and by the burning of coal-gas, &c., it is always present in larger quantities in dwelling-houses than in the open air. Carbon dioxide gas is also given off during the process of fermentation, and is found in the bottom of old wells, &c. The advantages to be gained by the use of this agent or medium are : non-inflammability, high specific gravity, thus rendering its heat of vaporisation for a given volume much higher than that of ammonia ; and non-corrosive action on copper, which latter quality is of special advantage in marine refrigerating installations. The objections to its use have been already gone into in a previous chapter. A simple and at the same time effective way to test the purity of liquefied carbonic acid is to solidify it, in which condition the slightest impurity can be instantly detected by smelling. A ready method of effecting this solidification is given by the Carbonic Acid Gas Com- pany, London, as follows : " Place the tube on a box or chair in a horizontal position, tightly fasten a small linen or canvas bag (4 to 6 in. square) over the nozzle of the tube, and open the valve fully. The acid will then stream out with full force, become solid inside the 9 130 REFRIGERATION AND COLD STORAGE. 3 2 I THE COMPRESSION PROCESS OR SYSTEM. 131 bag, and remain in that state for hours, evaporating only very slowly, and showing a temperature of about 200 Fahr. below freezing point." Carbon dioxide machines have already been dealt with on pages 45 to 47, where brief descriptions of the original machines of Wind- Fig. 71. Belt-driven Vertical Type Hall Carbonic Acid Compression Machine. hausen and Lowe will be found. As will be found there mentioned the Windhausen machine has been greatly improved by J. & E. Hall, Ltd., of Dartford, Kent, the proprietors of the original patents, who have been largely instrumental in introducing this system all over the world. 132 REFRIGERATION AND COLD STORAGE. Figs. 71 to 77 illustrate a small, exceedingly compact and well- designed belt-driven carbonic anhydride machine made by the above firm. The design of this machine is, it will be seen, both simple and compact, and as the use of this agent admits of a very small size of compressor being employed relatively to the work performed, the Fig. 72. Belt-driven Vertical Type Hall Carbonic Acid Compression Machine. Sectional View. whole machine occupies but little space. The general arrangement of the machine will be readily understood from the sectional view, Fig. 72, in which c is the compressor vertically mounted, as shown, on the side of the condenser tank or casing r, the latter being fitted with coil e. n is the evaporator casing fitted with an evaporator coil t, and arranged inside the condenser r, so that its lower part is surrounded by the latter, THE COMPRESSION PROCESS OR SYSTEM. 133 the condenser coils e occupying the annular clearance or space round the evaporator, and the evaporator casing n forming an insulated divi- sion between the condenser casing r and the evaporator coils t. o is the regulating or expansion valve or cock, and g and p are respectively the condenser and evaporator gauges, s is the separator, P is a patent safety valve, o is a patent hollow oil gland for preventing leakage taking place round the compressor piston rod. GO is the connecting rod, s is the crankshaft, D the driving pulley, and B the brine circu- lating pump. Figs. 73 and 74. Belt-driven Vertical Type Hall Carbonic Acid Compression Machine. Cross Section and Vertical Central Section through Cylinder. It will be seen that the machine consists essentially of a circular or rectangular cast-iron tank r carrying the compressor c, inside which tank are the condenser coils e, and inside these again is a double tank n, with insulation between and the evaporating coils t in the centre. The compressor cylinder c, which is shown in vertical longitudinal section in Fig. 74, and in transverse or cross section looking on back end in Fig. 73, is cast in a special hard bronze for these small-sized machines, by which means the two essentials of soundness and hardness are ensured, and the suction and delivery valves are identical for facilities of interchange. The compressor piston rod gland o is kept 134 REFRIGERATION AND COLD STORAGE. gas-tight by means of two cupped leathers on the compressor rod, as clearly shown in Fig. 74. A special oil is forced into the space between these two cup leathers at a pressure above the greatest pressure liable to occur in the compressor, so that whatever leakage takes place at the gland is a leakage of this special oil, either into the compressor cylinder, or out into the atmosphere, and there can be no leakage of the gas. What slight leakage of the special oil takes place into the compressor cylinder is advantageous, inasmuch as it serves both to lubricate the compressor and to fill up all clear- i ances. If the gland should require pack- ing, and no cup leathers be available, the special ring shown in Fig. 67 may be used with ordinary packing (see chapter on "Management," &c.). The loss of oil from the lubricator due to leakages is replaced by means of a small hand pump, a few strokes of which will be required to be made every four or five hours whilst the machine is at work, as may be indi- cated by the position of the piston rod of the pressure lubricator. The oil passing into the com- pressor cylinder serves the purpose, as above mentioned, of filling up the clearance spaces, and any surplus Fig. 75. - Belt-driven Vertical above what is ^quired for this pur- Type Hall Carbonic Acid Compres- pose will be discharged with the gas sion Machine. Vertical Section through the delivery valves. In through Spiral Packing Ring. or( i er to prevent the oil discharged with the gas from passing into the condenser coils, all the gas is delivered into the separators wherein it is made to impinge against the sides of the vessel, and the oil adhering to the latter drains to the bottom, and is drawn off from time to time as occasion may require, whilst the compressed gas passes off by an opening at the top on its way to the condenser. In the suction passage is fitted a suitable copper strainer as shown in Fig. 76. The condenser consists of coils e, of wrought-iron hydraulic pipe, usually of ~ in. bore, which in the submerged or immersed type employed in the present example are placed in the tank r, and THE COMPRESSION PROCESS OR SYSTEM. 135 surrounded with water. The coils are electrically welded together into such lengths as to avoid the presence of any joints inside the tank. The evaporator or refrigerator consists of an insulated tank n, containing nests of coils t, also formed of long lengths of electrically Fig. 76. Belt-driven Vertical Type Hall Carbonic Acid Compression Machine. Vertical Central Section through Suction Passage. welded wrought-iron hydraulic pipes within which the carbonic anhydride evaporates. The heat required for evaporation is obtained from the brine surrounding the pipes. A regulating or expansion valve o placed between the condenser coils e and the evaporator coils t admits of the quantity of liquid carbonic anhydride passing from the condenser being suitably regulated. To enable the compressor c to be opened up for examination of the valves and piston without loss of carbonic anhydride, stop-valves are fitted on the suction and delivery sides, by means of which the carbonic anhydride can be confined to the condenser and evaporator. As the machine might be again started, after being thus shut down, without the delivery valve being opened, which would lead to an excessive pressure in the delivery pipe, owing to there being _ no outlet from the latter, and probably result in the d r i ve n Vertical fracture of this pipe, a safety valve P is provided. Type Hall Car- This safety valve, which is shown in vertical central bonic Acid Corn- section, drawn to an enlarged scale, in Fig. 77, con- pression Ma- sists, it will be seen, of an ordinary spring safety ne ' , ^ er ' 1 . ca valve, at the base of which is a thin copper disc A, through Safety which is designed to relieve any excessive pressure, Valve. considerably below that to which the machines are tested. The disc is made perfectly gas-tight, an object which it would not be possible to obtain by means of the spring safety valve alone, and this latter only comes into action upon the rupture of the copper disc A. 136 REFRIGERATION AND COLD STORAGE. THE COMPRESSION PROCESS OR SYSTEM. 137 138 REFRIGERATION AND COLD STORAGE. Great care has necessarily to be exercised in making these copper discs, so as to guard against variations in strength, due to any differences either in the thickness or hardness of the copper sheets out of which the discs are made. About 1J brake horse-power is required to drive this smallest size self-contained vertical type of machine. A horizontal single-cylinder double-acting Hall carbonic anhydride steam-driven compressor, side by side pattern, is shown in Fig. 78. This type of compressor is arranged with the compressor and single steam cylinder side by side, both connected up to the same shaft. The machine is especially made for ice-making plants in which clear ice is made from distilled water. The machine shown in the illustra- tion has a capacity of 60 tons of ice per day. Fig. 79 illustrates a horizontal duplex Hall carbonic anhydride machine, fitted with compound steam cylinders arranged side by side, and with a surface or jet steam condenser located in the front part of the machine. The two compressors are, it will be seen, driven by tail rods from the steam cylinders, and the cranks of the latter are placed at right angles to each other, thereby ensuring an even turning movement. Each compressor cylinder is arranged to deliver the compressed carbonic acid or carbonic anhydride into an independent condenser consisting of coils of pipe, in which the compressed carbonic anhydride is condensed into a liquid form by the cooling water circulating round the pipes, the coils of pipes being contained in a steel casing through which the water is circulated. A separate evaporator or refrigerator is provided in connection with each of the above-mentioned condensers, this evaporator consisting of coils of pipes, in which the liquid carbonic anhydride evaporates, and during this process cools the brine surround- ing these coils. Figs. 80 and 81 show two of the most recent patterns of Hall carbonic acid compressors. The vertical belt-driven type shown in Fig. 80 is constructed in sizes of 1 to 5 tons ice-making capacity. The horizontal type illustrated in Fig. 81 is constructed in sizes of 6 tons ice-making capacity and upwards. The general construction of the above machines is clearly shown in the illustrations. The vertical machines of up to 2 tons ice-making capacity, however, are fitted with the Hall standard double-acting hard bronze CO., compressors. The larger vertical machines and the whole of the horizontal machines are provided with double-acting CO. 2 compressors, each cut from a solid ingot of special high carbon steel, THE COMPRESSION PROCESS OR SYSTEM. 139 and all sizes are provided with patent oil sealed glands and pressure lubricators. The compressor pistons are fitted with hydraulic leathers and the glands on the standard machines each contain two hydraulic leathers, the gland being kept tight by the oil from the pressure lubricator. In special cases, or for tropical work, however, the machines are frequently fitted with the Hall patent metallic gland Fig. 80. Vertical Type of Belt-driven Hall Carbonic Acid Compressor. Most Recent Pattern. packing, still retaining the pressure lubricator, and with metallic piston rings. The compressor suction and delivery valves are made interchange- able, and each are provided with separate and interchangeable valve seats. The valves and seats are made of special hard steel, and are so arranged that they can readily be withdrawn or replaced without disturbing any of the connections. As shown in the illustrations 6 00 <*> 140 THE COMPRESSION PROCESS OR SYSTEM. 141 both vertical and horizontal machines have the open type flat slipper guide, which gives much greater accessibility. All bearing surfaces Fig. 82. Vertical Type of Steam-driven West Carbonic Acid Compression Machine. are of ample size to ensure satisfactory and continuous working over long periods, H2 REFRIGERATION AND COLD STORAGE. Fig. 82 illustrates a steam-driven vertical carbonic anhydride machine, built by H. J. West & Co., Ltd., London. This type of machine is made in Various sizes, from No. 1 machine of 3 cwt. ice-making capacity per twenty-four hours, up to the No. 8 machine of 2 tons ice-making capacity per twenty-four hours, the smaller sizes Fig. 83. Vertical Type West Carbonic Acid Compression Machine. Vertical Central Section through Compressor Cylinder. being belt-driven. The amount of condensing water at 55 Fahr. required for the smaller size is 48 gals, per hour, and that for the larger 400 gals, per hour. The arrangement of this type of vertical compressor is very neat and compact. A rigid girder-shaped vertical cast-iron frame carries the com- pressor and motion work, and the perfect alignment of the piston rod THE COMPRESSION PROCESS OR SYSTEM. 143 and crosshead is secured by boring the pump seat and guide channel in one operation. The condenser, which is of the submerged type, is placed behind the compressor, and is coupled directly to it by an extension of the wrought-iron coil without any intermediate pipes or joints. These small machines have compressor cylinders cast from a special bronze alloy, combining the requisite strength and soundness, and finishing to a perfectly hard, smooth surface for the piston rings to work on. Fig. 84. Vertical Type West Carbonic Acid Compression Machine. Vertical Central Section through Valve. Enlarged Scale. The construction of the compressor will be readily understood from the vertical central section shown in Fig. 83. The suction and delivery valves are made exactly alike, and of the same size for the purpose of interchangeability, so that one spare valve will replace either. The valve, which is shown in central section, drawn to a greatly enlarged scale in Fig. 84, is made of tempered steel, and beats upon a hard phosphor bronze seat, forming a perfectly gas-tight joint when closed. Another point is that the weight of the valve is reduced to a minimum, and the lift is under one-eighth of an inch, so that it has no tendency 144 REFRIGERATION AND COLD STORAGE. bo hammer itself to pieces. The method of forming a gas-tight joint round the piston rod is shown in Fig. 83 and is, it will be seen, practically similar to that employed in Messrs Hall's carbonic acid compressor. Two capped hydraulic ram leathers are placed face to face upon the rod about 3 in. apart, the space between them being filled with oil, which is fed in from the small lubricator shown on the left-hand side of the illustration. The oil bath which surrounds the rod both effectively stops all leakage of gas, and, at the same time, serves to lubricate the piston rod and cylinder, and to fill up the clearance spaces. The surplus oil passing through the compressor is trapped in an oil separator, from which it can be removed as desired. A dead weight safety valve is fitted to all these compressors, except the very smallest size, and is set to blow off a little above the highest working pressure of the machine. The design and construction of this little machine is good, the bearings have liberal wearing surfaces, and are adjustable, thus reducing wear and tear to a minimum, and tending to prevent any noise when running. Special attention is paid to the lubrication of the working parts, every bearing and working surface is provided with an automatic lubricator, which feeds just sufficient oil to maintain the surfaces in proper working condition, and no more, thus preventing or greatly reducing dirt, waste, and the tendency to hot bearings. A standard pattern of belt-driven horizontal carbonic anhydride compressor is also made by the same firm. The steam-driven horizontal compressor is arranged tandemwise to the steam engine cylinder, and the compressor piston rod is coupled to a tail rod on the steam piston. Steam-driven horizontal compressors are also made of the duplex type, coupled direct to compound or triple expansion condensing steam engines, and so arranged that one-half the plant, consisting of com- pressor, condenser, and evaporator, may be disconnected for overhauling or repairs, whilst the other half continues in operation. Machines of 6 tons ice-making capacity and over are fitted with compressors bored out of a solid steel forging, by which both soundness and strength of material is secured, and furthermore, a hard, smooth, glassy surface for the piston rings and cup leathers to work upon. Kroeschell Brothers Ice-Making Co., of Chicago, 111., U.S., manu- facture carbonic anhydride machines of both vertical and horizontal patterns, the former being that used for the smaller sizes of machines, and the latter for the larger ones. Fig. 85 shows a front view of a small vertical belt-driven machine of J ton ice-making capacity per twenty-four hours, and requiring THE COMPRESSION PROCESS OR SYSTEM. 145 1 H.P. for driving purposes. This type of machine is made in seven different sizes, the smallest being the above, and the largest having an ice-making capacity of 3 tons per twenty-four hours, and requiring 12 H.P. Two vertical single-acting compressors are located inside the cast-iron condenser tank, which latter is mounted upon a frame Fig. 85. Vertical Type Belt-driven Kroescliell Carbonic Acid Compression Machine. consisting of a box casting carrying the crankshaft and guides. The compressor cylinders are made of semi-steel, which secures the two essentials of soundness and hardness, and the piston rods are provided with a patent stuffing box sealed with glycerine. This device consists of cupped leathers on the compressor rod, into the spaces or chambers 10 146 REFRIGERATION AND COLD STORAGE. between which glycerine is forced at a pressure superior to the suction pressure in the compressor, so that any leakage at the stuffing box is a leakage of glycerine, either into the compressor cylinder or out into the atmosphere, and not a leakage of gas. Obviously the leakage of glycerine into the compressor cylinder is an advantage, as it both serves to lubricate the piston and also to fill up all clearances. The glycerine is forced into the chambers by means of a hand pump, a few strokes of which are required to be made every four or five hours. Each cylinder has a suction and discharge valve, all of which are located at the top of a joint or common cylinder head, thus rendering them easily accessible. The valves are made of forged steel, and are so designed as to combine strength with lightness. On one side of the cylinder head is provided a filling valve, which can be easily connected by means of a short pipe with the ordinary drum of carbonic anhydride now in common use. Stop-valves are provided in the suction pipe as well as the condenser coil, so that the suction and dis- charge valves in the condenser coil can be examined without loss of gas. The condenser consists of a spiral coil made of extra strong iron pipe, surrounding the compressor, and is connected at one end with the discharge side of the latter, and at the other end with a combined separator and liquid receiver, placed at the back of the frame. The crankshaft bearings are formed in the cast-iron frame support- ing the condenser tank, and the double-throw crankshaft actuates the compressor pistons by means of strong yokes, having guides at the lower side, thus enabling the long connections, such as connecting rods and crossheads, which would be otherwise necessary, to be dispensed with. The double-throw crankshaft is made of forged steel, and is extended or overhanging at one side of the frame, so as to receive the fast and loose driving pulleys. The receiver consists of a strong wrought-iron cylinder, with a stop-valve located at the top, and a blow-off cock at the bottom, the latter admitting of the glycerine carried over from the cylinder being drawn off. A gauge mounted upon a three-way valve, by means of which it can be caused to communicate either with the compressing or with the suction side of the machine, is provided on the top of the condenser tank. On the opposite side of the machine to the driving pulleys is provided, as will be seen in the drawing, a small hand pump, by the operation of which the cylinders can be lubricated. A safety valve is also provided to guard against possible accident through neglect or ignorance on the part of the attendant. THE COMPRESSION PROCESS OR SYSTEM. 147 The larger sizes of vertical combined compressors and condensers are identical in design with the exception that they are fitted with connecting rods and crossheads instead of yokes, and these cross- heads and connecting rods, as also the main bearings and the double- throw crankshaft, are all of extra strength, and have large wearing surfaces, and every provision is made in them, as in the smaller machine, for meeting any excess of regular duty. All the machines are fitted with an automatic lubricating device. The machines are also built direct coupled with a vertical steam engine, or geared to an electric motor. Fig. 8(5. Horizontal Type Belt-driven Kroeschell Carbonic Acid Compression Machine. The larger sizes of carbonic anhydride machines constructed by the firm are, as before intimated, of the horizontal pattern, and their standard sizes run from 2 tons ice-making capacity per twenty-four hours up to 50 tons ice-making capacity per twenty-four hours, requiring respectively 8 H.P., and 120 H.P. for driving purposes. Fig. 86 shows a standard pattern of belt-driven Kroeschell hori- zontal double-acting compressor. The compressor cylinder is provided with a jacket through which the return gas passes, which arrangement it is claimed both imparts greater strength to the cylinder, and also 148 REFRIGERATION AND COLD STORAGE. keeps it perfectly cool. The piston rods, connecting rods, cranks, pins, and valves are made of forged steel, and the latter are made identical for facilities of interchange. O & H" oo d Leakage round the compressor piston rod is prevented by an arrangement similar to that used on the small vertical type of machine, but instead of the hand pump, a belt-driven pump operating con- THE COMPRESSION PROCESS OR SYSTEM. 149 tinuously is provided for replacing the glycerine which leaks out of the stuffing box. Any glycerine which passes into the compressor beyond what is necessary to fill the clearance spaces is discharged with the gas through the delivery valves. This glycerine is prevented from going into the system by a separator in which the glycerine drains to the bottom, and can be drawn off from time to time. As glycerine has no affinity for carbonic acid, and consequently undergoes no change in the machine, there is no chance of the condenser coils becoming clogged. The condenser consists of coils of wrought-iron extra Jheavy pipes so welded as to avoid any joints in the tank, and arranged either on the submerged or on the atmospheric or evaporative principle. Tho evaporator also consists of similar coils of pipes, a regulating or ex- pansion valve being provided between it and the condenser. The safety valve consists of a housing at the base of which is a thin disc, calculated to blow off at a pressure considerably below that to which the machines are tested. The joints have all special flange unions and brass bushings, and are made absolutely gas-tight with packing rings of vulcanised fibre which, whilst withstanding heat, have also sufficient elasticity to ensure the tightness of the joint when either hot or cold. The firm also make belt or rope driven horizontal double-acting double compressors arranged tandem-wise or in line, and driven from a crank on a central crankshaft. These machines are suitable for large installations. Fig. 87 illustrates a horizontal type of belt-driven Humboldt car- bonic acid compression machine. A feature in this machine is the facility with which the parts can be got at for inspection or repairs. The pressure valve is fitted with a safety device which is connected with the suction channel. Fig. 88 shows a large duplex carbonic anhydride compressor built by the Haslam Foundry and Engineering Co., Ltd. A carbonic acid machine made by the Cochran Company, Lorain, Ohio, United States, is of the belt-driven vertical pattern, and the compressor cylinder is mounted upon a box-shaped or hollow bed-plate on which is placed the condenser, thus forming a very compact and neat arrangement, and lending itself to transport. A later design of machine by this company has the hollow or box pattern bed-plate extended, and is driven by a motor mounted upon the latter. A compact and well-designed horizontal type of carbonic acid compressor is made by the Atlas Co., Ltd., Copenhagen, which firm 150 REFRIGERATION AND COLD STORAGE. 1- THE COMPRESSION PROCESS OR SYSTEM. 151 manufacture the refrigerating machinery under the Schou patents, originally made by the Tuxen & Hammerich Co. A recent design of carbonic acid machine built by Mollet, Fontaine, et Cie, of Lille, France, consists of a single-acting compressor direct- driven by a horizontal steam engine. The arrangement for forming a gas-tight joint round the compressor piston rod comprises a stuffing box having three compartments, the two outer ones being filled with glycerine, a small portion of which is drawn in by the rod into the inner box or compartment to act as a lubricant. One of these com- pressors was exhibited at the late Paris Exhibition in the French brewery section. Another carbonic acid machine shown at the above Exhibition was one built by Escher, Wyss, et Cie, Switzerland. This machine comprises a single compressor cylinder fitted with cast-steel valves on phosphor bronze seats, and driven direct by a horizontal 50 H.P. steam engine. The capacity of the machine is 12 tons of ice per twenty-four hours. Thomas Ths. Sabroe & Co., Ltd., Aarhus, Denmark, are manu- facturers of a vertical type of carbonic anhydride machine, which has the foundation plate of the compressor and the condenser cast in one piece, and all the parts made interchangeable. The general arrange- ment of the apparatus resembles that of Hall's vertical pattern machine. Carbonic acid machines are also made by Wegelin & Hiibner, Act.-Ges., Halle-on-Saale ; D. Stewart & Co., Ltd., Glasgow; and others, whose machines the space at our disposal does not permit us to undertake to describe here. CHAPTER VIII CONDENSEES AND WATEE COOLING AND SAVING APPARATUS Submerged Condensers Amount of Cooling Water Required Atmospheric or Open-Air Evaporative Surface Condensers Amount of Condenser Surface Required Amount of Cooling Water Required Supplementary Condensers or Forecoolers Double-Pipe Condensers Hendrick's Condenser Water Cooling and Saving Apparatus Water Cooling Towers. As has been already mentioned in the fifth chapter, one of the three essential parts of any compression machine is the condenser, the function of which is to supplement the action of the compressor or pump. The condensers in most general use may be classified under two main heads, the submerged type of condenser and the atmospheric or open-air evaporative surface type of condenser, the first having always some arrangement of coils immersed or submerged in a tank of cooling water, and the second invariably consisting of coils of pipe or tube exposed to the air, with water trickling over them. SUBMERGED CONDENSERS. The submerged type of condenser is the only one applicable in some cases, as for instance in marine installations ; it has, besides, certain specific advantages which will be next treated of, but it may be premised that it consumes a large amount of cooling water, which, where water has to be paid for at a high figure, may amount to a serious item in the working expenses. The system, however, admits of the condenser being located in any part of the building, or in the open air, as may be desired, occupies comparatively little space, allows the cooling water to be admitted to the condenser at the bottom near the exit for the condensed gas, so that the water gradually rises as it becomes warmer, until it is discharged at the top, whilst the warm 152 SUBMERGED CONDENSERS. 153 gas entering the condenser at the top-header, flows downward through the coils, and parting with its sensible and latent heat to the cooling COLO WATER INLET TURBINE TO OPERATE AGITATOR Fig. 89. Chew's Patent Submerged Type Condenser. Vertical Central Section. water becomes liquid and drains away to the bottom-header. And, finally, the submerged pipes in a condenser of this description remain 154 REFRIGERATION AND COLD STORAGE. clean, and therefore in an efficient condition, much longer than they do when exposed. To secure the utmost efficiency of a condenser of the submerged type it is absolutely necessary that the cooling water should be kept in a state of agitation by some suitable means so as to prevent the formation and collection of a film of warm water round the pipes. Several condensers of the submerged type have been already illus- trated, and briefly described, in connection with various compression machines, in previous chapters. Fig. 89 shows in vertical central section a patent condenser of the submerged type, invented by Mr Leuig Chew, and manufactured by Messrs H. J. West & Co., Ltd., London. The construction of this apparatus is almost sufficiently obvious from the drawing, and but little explanation is needed. A special feature is the automatic device for breaking up the above-mentioned film of warm water, and dispersing the air bubbles, thus bringing the cold water into intimate contact with the surfaces of the pipes, and promoting the most complete interchange of heat. This device con- sists of a revolving agitator, fitted with helical blades, which is slowly and automatically rotated by a small turbine fixed on the top of the condenser, and operated by the same water which is afterwards used to circulate through the condenser for cooling purposes. This arrange- ment offers the obvious advantage of saving the expenditure required for driving the agitator, as well as enabling the more or less complex arrangement of toothed gearing and belt pulleys, used when it is driven in that manner, to be dispensed with. Compound submerged condensers are also constructed by some makers. In one arrangement of this description the hot gas from the compressor is first passed into a primary condenser, consisting of a single coil of pipe submerged in a tank ; the gas and liquid leaving this coil at the bottom is passed on to a secondary condenser, and is there delivered by a distributing head, or manifold inlet, to the tops of three coils submerged in a second tank located above the first one. The cooling water is admitted to the bottom of the upper or secondary condenser tank, and is taken from the top of the latter to the bottom of the lower or primary condenser tank, and finally runs off by an overflow at the top of the latter. In a better arrangement than the above the single-coil primary condenser, to which the hot gas from the compressor is first delivered, is located on the top, and the secondary condenser with three coils to which the gas and liquid is next passed, is placed below or under- SUBMERGED CONDENSERS. 155 neath the former. The cooling water is, in this arrangement, delivered simultaneously to the bottoms of both condensers, and is finally run off in a like manner at the tops of them. Fig. 90 shows a pattern of condenser patented by H. H. Schou, which is divided into two or more sections, connected so that the cross area of a section will be suited to the state and feed of the cooling medium therein. These separate coils are either of equal or different lengths, and may be arranged in several ways. In the form shown in the drawing the liquefied agent enters the coil marked f, and as it evaporates passes through the coupling A, coils d, e, coupling i, and coils a, b, c, from which the gas is removed by the pipe g. A type of condenser, patented by Mr T. B. Lightfoot in 1885, consists of coils or zigzag pipes, arranged with one or more zigzag passages between them, formed in a tank or vessel, the arrangement being such that the water or re- frigerating medium enters the coils or zigzag pipes at the bottom, the vapour being drawn off by a pump at the top, whilst the fluid to be cooled enters the tank or vessel at the top of the tank, and after travelling along the whole length of each coil or zigzag, is drawn off at the bottom. The coils of pipe in a submerged condenser g cllo ^f p a t' e nt usually consist of IJ-in. to 2-in. pipe in one or more Condenser, sections, preferably a number connected by mani- fold inlets and outlets, so that one or more of the sections may be shut off for repairs, &c. In some constructions the pipe at the vapour inlet end is of larger dimensions, and arranged to taper down to the outlet end, the agent being there partially liquefied, and occupying less space. The amount of condenser surface to be employed is best determined by practice. According to Professor Siebel it has been found that for average conditions (incoming condenser water 70 and outgoing con- denser water 80, more or less) for each ton of refrigerating capacity (or for \ ton ice-making capacity) it will take 40 sq. ft. of condenser surface, which corresponds to 64 running feet of 2-in. pipe, or to 90 running feet of IJ-in. pipe. Frequently 20 sq. ft. of condenser surface, and even less, are allowed per ton of refrigeration (double that for actual ice-making capacity), but this necessitates higher condenser pressure, &c., and is deemed poor economy by many engineers. The Triumph Ice Machine Co. give for their ammonia condensers 156 REFRIGERATION AND COLD STORAGE. about 120 ft. of IJ-in. pipe, or 70 ft. of 2-in. pipe per ton. They also recommend at least 20 in. clearance space between the coils to admit of easy access to all parts; that the condenser should never exceed 20 ft. in length ; and that it should never be above sixteen pipes high. According to Professor Siebel* again the number of square feet of cooling surface P required in a submerged condenser may be approxi- mately calculated after the formula F = - /* sq.ft., in which h is the heat of vaporisation of 1 Ib. of ammonia at the temperature of the condenser, k the amount of ammonia passing the compressor per minute, and ra the number of units of heat transferred per minute per square foot of surface of iron pipe, having saturated ammonia vapour inside, and water outside, t represents the tempera- ture of the ammonia in the coils, and ^ that of the cooling water outside of the coils, i.e., mean temperature of the inflowing and out- flowing cooling water. Taking the figures already given as a guide, the factor m is equal 0-5, so that the formula reads *-j CS ^r-;fcfc This formula, like others which have been given on this subject, is, it must be understood, an empirical or experimental one. Referring to amount of cooling water required, the same authority observes that the heat which is transferred to the ammonia whilst pro- ducing the refrigeration, and also the heat equivalent to the work done upon the ammonia by the compressor (superheating being prevented), must be carried away by the cooling water, expressed in thermal units; and speaking theoretically, the sum of these two heat effects is equal to the heat of vaporisation of the ammonia at the temperature of the condenser. On the basis of this consideration, the amount of cooling water A, in pounds required per hour, may be expressed by the formula h.k x 60 or in gallons after division by 8 -33, the signs having the same signifi- cance as in the foregoing formulas, with the exception of t, which represents the actual temperature of the outgoing, and t v which repre- * "Compend of Mechanical Refrigeration," H. S. Rich & Co., Chicago, 1899. ATMOSPHERIC CONDENSERS. 157 sents the actual temperature of the incoming cooling water. Practically the amount of water used varies all the way from 3 to 7 gals, per minute per ton ice-making capacity in twenty-four hours. The following table, compiled by Mr Eugene T. Skinkle, gives the dimensions of submerged condensers of some plants in actual operation in the United States : DIMENSIONS OF SUBMERGED CONDENSERS. > * Tanks. O C c >, bJO 1 1 1 ft rt 'o r* ^ c & If if. l r V i 1 'B S U "S . ffi I c i 1 ftj" .s-.>. bf:2 i .SH h fe J S. "S a to 12.2 g a c c J3 .2 -^ c 1 s 1 IE fejO 5] I f I 1 1 SJ 3 o S OQ 1 H 6 II ^ 5 10 10 i 3 6iJA 9 12 7* 855 171 85-5 10 20 10 7i 3 TTT 20 12 7i 1,900 190 95- 12| 25 10 71 6^ 1% 22 12 7| 2,090 167 83-6 15 30 10 6| TJT 25 12 7| 1 2,375 151-6 79-16 20 35 10 10^ ITT 27 12 2,565 128-25 73-28 30 50 10 10 12i 27 24 71 5,130 171 102-6 40 75 14 10 1S| a 27 24 H| 7,695 191-1 102-6 60 110 14 13 13J ft 35 24 UJ 9,975 166-25 90-68 Average - 167- 89- ATMOSPHERIC OR OPEN-AIR EVAPORATIVE SURFACE CONDENSERS. In this class of condenser the lines of pipes or tubes through which the agent passes are so located as to be exposed to more or less con- stant currents of air, and generally, in addition to the latter, cooling water is caused to trickle over the pipes. The vaporised agent should preferably be passed in this arrangement in an opposite direction to the cooling water. That is to say, it should be admitted at the bottom of the condenser, and in this case the liquid, as fast as it is formed, passes off to the side into a vertically-placed manifold. By this means the warm gas entering the condenser meets the warmer water, and the gas as it ascends in the condenser constantly meets colder water, until its temperature is nearly reduced to that of the water when it first comes in contact with the condenser pipes, liquefaction then taking place. Atmospherical condensers which are said to give excellent results are also formed of vertical sections of pipe, the compressed vapour being delivered to each section at the top from a common manifold or 158 REFRIGERATION AND COLD STORAGE. distributing head, and discharging the liquid at the bottom into another common manifold or distributing head, which latter is connected with the liquid receiver. The ordinary form of atmospheric condenser is of very simple construction, and consists essentially of a stack of tubes placed in lines, with return bends and heads, and some water-distributing arrangement. Fig. 91 is a diagram showing a simple plan for distributing the water, which is self-explanatory. It will be noted that the cooling water should pass through an exactly contrary sequence to that undergone by the compressed vapour, viz., during its downward course it should . Ihh-rir^Ht^ i * LI ^y^^^^a^.^Hf) [ C'/.-;-',>^y^v: v r/-: \ L '''.'.' ; ::"':. g \ J>s . .-,. .r,^,- 1 ,^-';---;-:^'-.-^'^,- 1 ^ ) /" ^.'. .'.'-. '.'.::.- ...''"1 7 ( v-" v ' J L^i- ' ' ' ' 1 / F (to^i^l Q[SJ -: ; '.:,-/j-::.. r 3222SSS :-...,... .'.-. ,.".' ' . P\ G'::^v'-vi'. : ^ ;; ^^^^^^g ) Fig. 91. Diagram showing Simple Method of Distributing Water in Atmospheric Condenser. constantly meet warmer gas or vapour, and consequently be gradually increased in temperature until it finally leaves the condenser by the trough shown at the bottom. By means of this gradual extraction of heat the difference between the initial and final temperature of the water will be greater than could be obtained were the gas and the water to flow in the same direction. In the De La Vergne, Eclipse, and other standard American condensers, the gas enters at the bottom, whilst the cooling water is applied at the top. In Fig. 92 is a diagram showing a common arrangement for the dis- tribution of water, n indicating the water trough in transverse section, and s the condenser tubes through which the hot gas or vapour passes. ATMOSPHERIC CONDENSERS. 159 This arrangement, it will be seen, results in the water spattering to such an extent that partitions have to be provided between and at the ends of the series of vertical coils. Fig. 93 shows diagrammatically a very simple plan, given in an American journal, for avoiding this objection- able spattering, which consists of a strip of metal or fin, T, which is attached to the underside of each of the condenser pipes or tubes s, and which serves to guide the water falling from the trough R quietly to the top of the pipe or tube below where the stream divides, one-half pass- Fig. 92. Diagram showing Objec- tions to Common Plan of Distribut- ing Water in Atmospheric Con- densers. Fig. 93. Diagram showing Method of avoiding Spattering in Distributing Water in Atmospheric Condenser. ing down and round one side of the tube, and the other half down the other side of the tube as shown. Fig. 94 shows an arrangement adopted by some American and other makers for removing the liquefied agent from the condenser, and delivering it into the storage tank, as soon as formed. This is effected by the introduction of drip-pipes v, connected with the return heads u of several of the coils of pipe or tube s, and with the storage tank or liquid receiver w, so as to draw off the liquid at different levels. 160 REFRIGERATION AND COLD STORAGE. In this manner the liquid formed near the top of the condenser at a lower temperature is prevented from falling to the warmer lower coils, in which a reabsorption of a certain amount of heat would take place, with a resultant loss of work. Fig. 95 illustrates an open-air evaporative surface condenser, built by Messrs Haslam, of Derby, which is arranged to work upon the principles above enunciated, by which the greatest possible amount of efficiency is secured. The condenser shown is built in a nest of five sections, thus rendering it more convenient for transport, and also admitting of easy access being had to all parts of the apparatus for repairs. Each section is provided with indepen- dent valves and cocks, so that any particular section may be shut off at any time if desired. Fig. 96 shows the Haslam interlaced type of ammonia condenser. In this pattern each nest is composed of three independent coils of pipe welded into one continuous length. The ends of the three coils are connected to headers at the top and at bottom, thus making each nest complete in itself. Valves are provided to isolate each nest, and these in turn are connected by headers, the number of nests being in accordance with the size of the machine. A slotted pipe is provided at the top of each nest to distribute the water, which in this type of condenser is generally circulated over and over again, being cooled by evaporation into the atmosphere. This type of condenser is useful where water is scarce, only a small quantity being required to make up the losses due to evaporation, wastage, &c. In Fig. 97 is illustrated an atmospheric or open-air condenser made by the Triumph Ice Machine Co., Cincinnati. This condenser is arranged in sections, and is so constructed as to permit of the ready removal of any pipe or fitting, without the necessity for shutting down the plant or losing any of the agent. The apparatus has double, extra heavy, wrought iron pipe headers. Fig. 94. Arrangement for Removing Liquefied Agent from Atmospheric Condenser. ATMOSPHERIC CONDENSERS. 161 The atmospheric condensers designed and manufactured by the Fred. W. Wolf Co., of Chicago, has pipes made from selected skelp, with drop-forged Bessemer steel flanges screwed on to same whilst hot, thus admitting of its shrinking in place when cool. Galvanised iron troughs, fitted with a patent levelling device, are provided for distri- buting the cooling water, and perforated steel strips are secured between the pipes. An inlet and an outlet valve are fitted to each section, so that anyone of them can be emptied without interfering with the operation of the others. Fig. 95. Haslam Atmospheric or Open-air Evaporative Surface Condenser. In Fig. 98 is illustrated an atmospheric or open-air evaporative surface condenser, built on Kau's system, with either copper or iron pipes, by Quiri & Co., Schiltigheim, Alsace. The construction of this condenser will be readily understood from the engraving. Evaporative condensers are also cooled by artificial currents of air, propelled by a fan or blower, in which case a very powerful evaporation is established. Whether or not an arrangement of this description would prove to be an economical one, depends upon the temperature and cost of the cooling water procurable relatively to the cost of driving the fan. ii 1 62 REFRIGERATION AND COLD STORAGE. ATMOSPHERIC CONDENSERS. 163 Fig. 97. Triumph Atmospheric or Open-air Evaporative Surface Condenser. Fig. 98. Rau's Atmospheric or Open-air Evaporative Surface Condenser 164 REFRIGERATION AND COLD STORAGE. The amount of condensing surface for an open-air condenser is, according to Professor Siebel, 40 sq. ft. per ton of refrigerating capacity (or for one-half ton ice-making capacity), which amount is equivalent to 64 running feet of 2-in. pipe or to 90 running feet of 1^-in. pipe. The amount of cooling water required for an open-air or atmos- pheric condenser is upward of 50 per cent, less than that required for a submerged condenser, and if made of sufficient height, the same water may be used repeatedly in an open-air condenser. The following table, compiled by Mr Eugene T. Skinkle, gives the dimensions of open-air or atmospheric condensers of some plants in actual operation in the United States : DIMENSIONS OF OPEN-AIR OR ATMOSPHERIC CONDENSERS. ^ fc Condenser Pans. c ..-. be 'i i 1 I c j 1 &\ 1| 1-9 || th of Pan Feet. h of Pan Feet. h of Pan Inches. kness of n Inches. mber of Pi High. mber of Pi Wide. c I PH 15 (T Sis t C *J * 11 *U g O, M SI 8,1$ SS 3 ^^1 w 8 (a .s ^ ^l Z C/3 I o H ^ 12* 25 21 10f 8 A 40 5 1 17 3,680 294-4 147-2 20 35 24* 10| i 8 A 40 5 1 21 4,440 222 126-8 30 50 24* 14 8 A 50 7 1 21 7,750 258-3 155 40 75 24* 14 8 A 50 T 1* 21 7,750 193-75 103-33 50 100 24* 14 8 3 TiT 90 7 1 21 13 950 279 139-5 60 125 24* 14 12 TB 80 7 u 21 12,400 206-6 99-2 80 150 274 17 12 A 80 7 M 24 14,080 176 93-86 Average for 1 in. pipe per ton Average for l|-in. pipe per ton - 263-42 192-12 142-12 98-79 SUPPLEMENTARY CONDENSERS OR FORECOOLERS. An arrangement intended to create a saving of power and of cooling water is a supplementary condenser or forecooler consisting of one or more coils of pipe through which the hot compressed gas is caused to pass before entering the main condenser. This supple- mentary condenser is cooled by the overflow water from the main condenser. When the supplementary condenser consists of one coil only it should be equal in size to the discharge pipe from the com- pressor. Should a series or number of coils be provided, however, DOUBLE-PIPE CONDENSERS. 165 the manifold pipe and the aggregate area of the small pipe openings should be equal to that of the discharge pipe. WESTERLIN-CAMPBELL AND HASLAM DOUBLE-PIPE CONDENSERS. The Westerlin-Campbell condenser, which is shown in side and end elevation in Figs. 99 and 100, consists of a coil made up with one pipe inside another, the water being on the inside of the internal pipe, and the hot compressed gas in the annular space or clearance between the pipes. This type of condenser is an attempt to secure the best features of both the submerged and atmospheric types in one apparatus, and is specially suitable wherever the water is to be used over again for some other purpose, and where the open-air type cannot be used by reason of structural difficulties. The hot gas is arranged to travel in a downward direction, and the cooling water in an upward direction, so effecting an interchange of temperature that results in the warmer water meeting the current of the warmest gas. The condenser is constructed in a nest, comprising several sections or stands, so that any one section can always be cut out for repairs, without having for that reason to shut down the plant, and such a cross connection of the water con- nections is provided that the water current can be reversed w T hen it is desired to wash out the internal pipe. Fig. 101 illustrates the Haslam type of double-pipe ammonia con- denser. The pipes containing the ammonia gas to be condensed are 2-in. bore, built up in the same manner as the other Haslam condensers, and through the centre of each a 1 J in. bore pipe passes. These are connected at the ends by U-shaped bends removable for cleaning purposes, and through this inner pipe the cooling water passes, being thus brought into intimate contact with the ammonia. An advantage of this type of condenser is that the water may be maintained under pressure, and raised to a height to be used for other purposes afterwards without further pumping. No tray is required under condensers of this type. An objection to this type of condenser would appear to be the liability of the deposit of scale in the pipes from certain classes of water. HENDRICK'S CONDENSER. This type of condenser differs from those previously described. It consists essentially of a vertical cast-iron shell, containing two or more spiral coils of IJ-in. pipe of extra thick gauge, the tail ends of 1 66 REFRIGERATION AND COLD STORAGE. o ab 167 1 68 REFRIGERATION AND COLD STORAGE. which project through the heads or covers of the shell and are con- nected together by suitable manifolds. The hot compressed gas is delivered into the upper part of this shell, and the condensing water is circulated through the spiral coil or coils of pipe located therein. The hot compressed gas is liquefied by reason of the pressure and by coming into contact with the coil or coils, and the liquid will collect at the bottom of the shell, which thus forms also a storage tank or receiver for the anhydrous liquid, from which it can be discharged into the evaporator or refrigerator. The shell is fitted with a level and gauge to indicate the amount of liquid therein. WATER-COOLTNG APPARATUS. In large towns and cities where the water from the water com- panies' mains has to be used, and paid heavily for, it is often doubtful economy to attempt to reduce the temperature of the condensed gas below a certain point, say 60 Fahr. during the winter months, and 70 Fahr. during the summer months. It is obvious that when a high price has to be paid for the water employed for cooling and other purposes, every effort possible should be made to utilise it to the fullest extent, and, with this end in view, it is desirable to use the overflow water from the condenser for boiler-feeding purposes, or to employ some means, such as a cooling tower, for saving that which would be other- wise run to waste and be completely lost. Fig. 102 shows the Haslam type of open water cooler, which is a simple and at the same time efficient apparatus. It consists of one or more nests of lap welded wrought-irori pipe, fitted with malleable iron return bends and flanges. Through these pipes the liquefied ammonia is evaporated, and the water to be cooled is distributed in a thin film over the cooler by means of a slotted pipe placed over same. As the water falls it is cooled to any desired temperature, Puplett's water saving and cooling apparatus is illustrated in Fig. 103. It is claimed that the use of this contrivance enables the con- densing water to be used over and over again with comparatively little loss, the waste indeed being practically confined to the quantity taken up by evaporation, which loss is, of course, more considerable in hot weather, and the consumption of condensing and circulating water is thus minimised as much as possible. It is stated to have been clearly demonstrated that in regular working for a considerable period, with a temperature in the sun of 93 Fahr., the entire loss experienced did not exceed 3 per cent, of the total quantity of water circulated. WATER-COOLING TOWERS. 169 The cost of the upkeep of the apparatus, moreover, is trivial, being one farthing per thousand gallons cooled, and the power required under ordinary conditions is 1 H.P. indicated for the same amount. The scope of this work does not admit of entering into an extended dissertation upon what are known as cooling towers, consequently space can only be found for a few general remarks and very brief descriptions of some examples of water-cooling towers, with which this chapter will be brought to a conclusion. i/o REFRIGERATION AND COLD STORAGE. First, as regards the general efficiency of any apparatus of the kind under consideration, this will be found to depend upon the following three principal points, viz. : The extent of the water surfaces exposed. The quantity of air that is brought into contact with those surfaces. And, thirdly, upon the difference of pressure which exists on the vapours at the water surfaces, and in the surrounding atmosphere. The first two will be seen to relate to the construction of the apparatus, the third to the general or normal atmospheric conditions. From the above it will be gathered that the chief features to be looked for in a water-cooling apparatus are the provision of the maximum amount of cooling surface, the most even distribution of the water over this cooling sur- face possible, and an effective air circulation. Cooling towers are extensively em- ployed in the United States in connection with refrigerat- ing plants, and the following very brief descriptions of a few of the best known will give an idea of their con- struction. The Worthington consists of a steel tower enclosing the evaporating surfaces, which latter are formed of hard glazed tiles, supported upon ~f~-beam grating, or of re- galvanised tube tiling. The Klein is constructed entirely of wood, a polygonal vertical shaft forming the frame for a checker- work of boards, which are arranged in horizontal layers. The Stocker, which consists essentially of a strong wooden casing, the interior of which is made up of cross-pieces of boards arranged in horizontal layers set at right angles to each other, and having between their intersections upright oblique partitions. The water is distributed by a system of funnel-shaped troughs at the top of the structure. The Barnard has a steel casing within which are hung a number of mats made of a special galvanised wire cloth. In all these cooling towers except the Stocker one fan only is employed, the latter has two fans mounted upon one steel shaft at the Fig. 103. Puplett's Water Saving and Cooling Apparatus. WATER-COOLING TOWERS. 171 base of the apparatus, which arrangement is claimed to enable a more equal distribution of the air to be effected, and a saving of driving power, as compared with the amount of air discharged. The Zschocke cooling tower is also said to afford first-rate results, and to be most economical in working. This apparatus consists essen- tially of a main distributing water-trough located above the cooler, into which the water to be dealt with is delivered direct, or, where it con- sists of injection water carrying a considerable amount of oil, after passing it through an oil filter. In the walls of this main distributing trough, and near its bottom, are fitted a number of small iron pipes, through which the water will pass into a series of smaller dis- tributing troughs, the walls of which are serrated both top and bottom, so as to cause the water to be distributed in drops over the top layer of the wooden battens composing the body of the cooler. These battens are evenly spaced, and are placed at a slight inclination, so that each drop of water will be caught and broken on the rough surface, and will spread itself out into a thin film, which will flow down each of the battens, and again form itself into drops on the lower edge of it, owing to its being also serrated, and will fall on to the next batten in the layer below, and so on, until the bottom or lowermost layer is reached. The air has free access to every batten, and consequently as the water parts with a portion of its heat at each, it will fall into the receiving tank beneath in a suitably cooled condition. The open type of cooling tower is provided at the sides with louvres, which serve to prevent the water from being blown away in the case of strong winds, whilst at the same time admitting air to every part. The Triumph Ice Machine Co.'s water-cooling tower is shown in Fig. 104. This apparatus works on the principle of exposing the water to be cooled in a thin sheet to the cooling effect of the atmo- Fig. 104. Triumph Water- Uooling Tower. Elevation. i;2 REFRIGERATION AND COLD STORAGE. sphere, the result being said to be increased in the above tower by imparting to it a rotary motion against the air current. This rotary Fig. 105. Haslam Water-Cooling Tower. motion is given by a small water-wheel in the manner plainly shown in the illustration. A cooling device made by the Linde Company for use in connection WATER-COOLING TOWERS. 173 with submerged condensers consists of the following arrangements : The condenser pipes are placed in an iron tank, the cooling water being kept in motion by a stirrer. At the top of the tank is provided a number of sheet-iron cylinders, so arranged that they are immersed in the w r ater below to the extent of about one-third of their diameter. These cylinders are caused to rotate slowly upon their axis, and their water-covered surfaces are subjected to the action of a current of air generated by a fan, the consequent evaporation producing the cooling effect. This apparatus is identical in principle to the Wetzel pan for concentrating the syrup or liquor in the manufacture of sugar. Fig. 105 illustrates the Haslam water-cooling tower, which consists of a wrought-iron casing containing galvanised corrugated wrought-iron plates. The overflow water from the condensers enters the cooler at the top and falling over the plates, comes in contact with a current of air induced by the fan shown in the drawing. The cooled water falls into a tank under the cooler, and is again raised to the distributing tank over the condensers by a centrifugal pump. CHAPTER IX THE ABSORPTION AND BINARY ABSORPTION PROCESS OR SYSTEM The Principle of the Absorption Process Early Machines Later Patterns of Machines The Binary Absorption Process, or Machines using a Compound or Dual Liquid. THE principle involved in the operation of machines for the abstraction of heat by the evaporation of a separate refrigerating agent of a volatile nature under the direct action of heat, and without the use of power, which agent again enters into solution with a liquid, is, as has been previously observed of the liquefaction process, more a chemical or physical action than a mechanical one. It is founded upon the fact of the great capacity possessed by water for absorbing a number of vapours having low boiling points, and of their being readily separable therefrom again, by heating the combined liquid ; hence it is commonly known as the absorption process. The absorption process was invented by Ferdinand Carre (brother to Edmond Carre, whose sulphuric acid freezing apparatus has been previously mentioned) about the year 1850. This system involves the continuous distillation of ammoniacal liquor, and requires the use of three distinct sets of appliances, viz. : First, for distilling, condensing, and liquefying the ammonia. Second, for producing cold, by means of a refrigerator, and absorber, a condenser, a concentrator, and a rectifier. Third, pumps for forcing the liquor from the condenser into the generator for redistillation. The three operations are each distinct from the other, but when the apparatus is in actual work they must be continuous, and are dependent upon one another, forming separate stages of a closed cycle. An advantage of the absorption process is that the bulk of the heat required for performing the work is applied direct without being transformed into mechanical power. The first machines, however, constructed upon this principle were very imperfect in operation, by reason of the impossibility of securing an anhydrous product of dis- 174 THE ABSORPTION PROCESS OR SYSTEM. 175 tillation, and as the ammonia distilled over contained as much as 25 per cent, of water, a very large expenditure of heat was required for evaporation, and the working of the apparatus, moreover, was rendered intermittent. This was owing to the distillation, which is the most important operation, and has of necessity to be executed in a rapid manner, being, in the first machines, very imperfectly effected, and the liquor resulting therefrom being naturally much diluted with water. Another serious result of the above defect was the accumula- tion of weak liquor in the refrigerator, and the consequent necessity for constant additions of ammonia. By subsequent improvements, however, made by Rees Reece in 1867-70; Mort in 1870, who introduced an improved temperature exchanger or economiser; H. F. Stanley, 1875; F. Carre (the original inventor), in 1876; W. H. Beck, in 1886; Mackay and Christiansen, and E. H. Tomkins, in 1887 ; and later still in the same year by E. L. Pontifex, the distillate has been rendered nearly anhydrous, and absorption machines have been brought to a very considerable degree of efficiency. In Fig. 106 is illustrated F. Carre's continuous-acting absorption machine. As above mentioned, the agent employed in this apparatus is ammonia. In the drawing A indicates the generator, B is the liquefier, c is the refrigerator, D is the absorber. Aqua ammonia is introduced into the generator A, the level of the liquid being indicated by a gauge glass, which is shown on the left-hand side of the generator, and which is practically similar to that used on steam boilers, and the evaporation is effected by heat from the furnace shown beneath. The gas from the generator A is conducted by a suitable pipe E to the lique- fier B, wherein it passes through a congeries or series of coils or zigzags arranged in a bath of cold water, which is kept constantly renewed from the reservoir F. By the time the ammonia has reached a vessel situated at the termination of the coils or zigzags in the liquefier it is in a liquid condition, and under a pressure of about 150 Ibs. per square inch, which pressure is constantly maintained in the generator A. In the liquid state the ammonia flows through the pipe G to the regulator H, by which it is admitted to the distributor I through a pipe K, which latter is wound spirally round the pipe or tube L, which is of larger bore, and through which the vaporised or gasified ammonia returns from the refrigerator c after having performed its heat-absorb- ing duties therein. By this arrangement the returning vapour or gas is made to do some further work by absorbing or taking up heat from the liquid ammonia on its way to the refrigerator. 1 76 REFRIGERATION AND COLD STORAGE. The refrigerator represented in the drawing consists of a set or series of six or other suitable number of spiral or zigzag tubes c 1 , c 1 , which return upon themselves, forming an equal number of partitions I so G in the tank wherein they are immersed, which latter is lagged with suitable non-conducting material. Each of these zigzags receives an equal supply of the liquid ammonia from the distributor I, and the THE ABSORPTION PROCESS OR SYSTEM. 177 space in the insulated tank surrounding them is filled with some uncongealable liquid, or one that will congeal only at very low tem- peratures, such as alcohol, or a solution of chloride of calcium or of common salt, which is usually known as brine. The ice cans or cases are immersed in the liquor between the zig- zags, and are sustained upon a carriage capable of being moved by the same mechanism that works the pump M, by which the re-saturated solution of ammonia and water is returned to the generator. The ammonia gas or vapour from the zigzags in the refrigerator c is collected in the cylindrical vessel N, from which it passes up through the tube L to the absorber D, where it meets the water that has been brought from the bottom of the generator A, and which partially fills the latter. This water being nearly free from ammonia, it having been exhausted therefrom by evaporation in the generator A, greedily absorbs or takes up the ammonia gas or vapour injected into it from the tube L. The absorber D is fitted with a worm D 1 which receives cooling water from the supply tank F, and the water from the generator A, which is brought by the pipe o, is first passed through the coolers P, P 1 , before delivery into the absorber D, and is thereby cooled so as to fit it to absorb the ammonia gas or vapour in the absorber D more freely. The transference of the water from the bottom of the generator A to the absorber D is effected by the pressure in the former, whenever the stop- cock or valve o 1 in the pipe o is opened. The pipe o is carried in a double coil through the cooler P, which consists of two concentric cylinders, and in a single coil through the cooler P 1 , dis- charging through a sieve, strainer, or perforated tray, in a fine shower into the absorber D. The strong ammoniacal solution from the absorber D, which is considerably reduced in temperature, is passed through the spaces round the coils of pipe o in the cooler p, and whilst reducing the temperature of the hot exhausted solution or water from the bottom of the generator A on its way to the absorber D, is itself raised several degrees before being returned to the generator, to the mutual advantage of both. The coil of pipe o, in the second cooler p 1 , is water cooled from the supply tank F. The saturated solution from the absorber D is drawn off by the force pump M (which is driven by a steam engine or other motor), through the pipe R, and is delivered thereby to the space round the coil in the cooler p, passing from the cooler, through the pipe T, to the dome on the upper part of the generator A, where it falls upon, and trickles downward through, a series of perforated strainers or trays, whilst the ascending ammoniacal gas or vapour, on the other hand, 12 178 REFRIGERATION AND COLD STORAGE. takes a sinuous upward course, alternately passing round the edge of one of the trays, and through a central hole or aperture provided in the next, and so on to the gas or vapour pipe E ; any aqueous vapour, which might otherwise be carried off with the ammoniacal gas or vapour, being thus condensed and returned to the generator. The constant pressure maintained in the generator A is, as already mentioned, about 150 Ibs. per square inch, and to prevent this pressure from being exceeded a safety valve is provided on the dome of the generator. And gas that escapes through this safety valve is led through a suitable pipe to a small water tank, where it is absorbed. As will be seen from the above description, the operation is, shortly, as follows : The aqua ammonia is first introduced into the generator A, the gas or vapour expelled therefrom by heat into the condenser B; and so that the process may be carried out continuously and not be arrested by the exhaustion of the solution, the exhausted or impoverished liquor is slowly drawn off at the bottom of the generator, an equal volume of fresh strong solution being constantly inserted at the top thereof. The united effects of the cooling and pressure produce liquefaction of the ammoniacal gas or vapour in the condenser, and the liquid ammonia passes to the refrigerator. It will be seen that the ammoniacal gas or vapour from the tubes of the refrigerator is re-absorbed, and a rich solution is formed to feed the generator, the absorbing water used being that withdrawn exhausted from the latter. Thus the generator and the condenser will keep up a continuous supply of the liquid, and the refrigerator will continue to freeze successive charges of water in the ice cans or cases, provided, however, that the requisite heat to vaporise or gasify the ammonia is supplied to the generator. If, there- fore, the entire apparatus be perfectly fluid-tight, as it is theoretically supposed to be, no escape could take place by leakage or otherwise, and the same materials would go on indefinitely producing the same uniform effect. In starting a machine constructed on the absorption principle it must be first blown through to expel all the air. In Carre's apparatus the air escaping from the absorber is conducted by a suitable pipe into what is known as a purger, where it is passed below the surface of water to absorb or retain any ammonia that would otherwise escape with the air. A large amount of water is required for cooling purposes in the condenser or liquefier, and absorber, and a considerable consumption of fuel is also necessary to heat the generator, when this is performed THE ABSORPTION PROCESS OR SYSTEM. 179 directly by means of a furnace, as above described ; when, however, this is effected by steam-heated pipes, as in Stanley's 1875 patent, or, as will be described later on, by coils of pipe heated by the exhaust steam from an engine, or even by direct or live steam from a boiler, there is a considerable saving on this head. Steam or other motive power is likewise required for driving the force pump. It is claimed by Mr Carre that for each pound of coal consumed as fuel, from 8 to 12 Ibs. of ice can be produced, in accordance with the size of the apparatus. For working the larger form of machine, capable of making 500 Ibs. of ice per hour, two men are required ; the force pump is capable of forcing 220 gals, of liquid per hour into the generator, and during the same time 100 Ibs. of pure ammonia is liberated from solution, liquefied, evaporated, and re-dissolved or re- absorbed. Rees Reece's chief improvement is founded on the fact that two vapours having different boiling points, when united, can be recovered by fractional condensation, and by means of his apparatus a prac- tically anhydrous distillate can be obtained. The special feature in the invention described in his 1867 patent is the method of obtaining nearly anhydrous liquid ammonia by means of an analyser, a rectifier, and a condenser, the peculiar construction and arrangement of which enables a continuous distillation and rectifi- cation of a dilute solution of ammonia to be effected upon the separa- tive principle. The ammoniacal gas is reduced by its own pressure to a liquid condition in the condenser, from which it passes into the refrigerator at a very low temperature, quickly abstracting the heat from any fluid passed through the latter. A boiler is connected with an analyser consisting of a series of plates arranged in the usual manner within a strong iron vessel. The analyser is connected with a rectifier, which is provided with a series of vertically arranged tubes surrounded by cold water, through which tubes the ammoniacal fluid passes to the condenser; or in an alter- native arrangement the rectifier is provided with a series of vessels placed one above the other with a space between them, the vessels being so connected that a passage is formed from end to end thereof for a continuous stream of cold water. The condenser is either fitted with tubes and is practically similar in construction to the first arrange- ment of rectifier above mentioned, or it consists simply of a cylindrical or other suitably shaped iron vessel, of sufficient strength to resist the internal pressure of the gas, and immersed in cold water. From this condenser the condensed ammonia passes to a refrigerator, which may i8o REFRIGERATION AND COLD STORAGE. be of any convenient form and construction. The liquid cooled in the refrigerator parts with the greater portion of its heat to the condensed ammonia, which is again vaporised, and in this form passes into an absorbing vessel which is kept cool by water, and which serves to maintain the required vacuum in the refrigerator. The ammoniacal solution passes from the absorber into a heating vessel, from which it is returned into the analyser. The latter may, however, on occasions be dispensed with, and the boiler connected directly with the rectifier. In his 1870 invention further improvements are introduced, and the entire apparatus comprises a generator, an analyser, a rectifier, a liquefactor, a receiver, a refrigerator, an absorber, and a heater, an engine placed between the refrigerator and the absorber being some- times, moreover, employed. The first five of these vessels form what may be called the distillery part of the apparatus, and the main object of these improvements is likewise to ensure the more perfect elimination of liquid ammonia in an anhydrous condition, or practically so, from its aqueous solution, and in one continuous uninterrupted operation. The analyser consists of a vessel fitted with a series of perforated cups or dishes, a dividing plate, an overflow pipe, and a dead plate or baffle to prevent the direct passage of the steam through the cylinder. The absorber comprises a series of pipes arranged together within a tank or cistern. The ammoniacal gas eliminated from its solution in water by the action of the generator, analyser, and rectifier, passes onwards to the liquefactor or liquefier, wherein by its own pressure it is reduced to a liquid, and is collected in the receiver; the liquid ammonia so obtained being practically anhydrous. This anhydrous ammonia is then passed into the refrigerator, in which is placed a coil of pipe, any liquid passing through which will be cooled by the evaporation of the liquid ammonia surrounding it. The refrigerator is connected through a stop-cock or valve to another coil contained or enclosed in an iron pipe, which coil extends to the absorber vessel, the latter being connected to the coil of piping contained in the refrigerator. The object of this second vessel and coil is to effect an interchange of temperature with the gas. During its further onward passage to the absorber the ammoniacal gas comes in contact with the spent or exhaust liquor of the distilling apparatus in which it dissolves, yielding back the original quantity of the ammonia solution, to be used over again repeatedly without any appreciable loss or waste. This solution of ammonia is forced by THE ABSORPTION PROCESS OR SYSTEM. 181 a pump into the top of the analyser, wherein the ammonia is separated from the water, and passes to the condenser to be liquefied, whilst, on the other hand, the exhausted liquor goes to the generator, and from thence into the temperature exchanger or heater, and on to the absorber. The tension or elastic force possessed by the gas as it passes from the refrigerator to the absorber, especially when employed for cooling water, admits of its being utilised for driving the pumps of the apparatus, or for other purposes. The operation of Reece's improved apparatus is briefly as follows : The charge of liquid ammonia (the ordinary commercial quality of a density of 26 Beaume) is vaporised by the application of heat, and the mixed vapour of water and ammonia passed to the vessels called the analyser and the rectifier, wherein the bulk of the water is con- densed at a comparatively elevated temperature, and is returned to the generator. The ammoniacal vapour or gas is then passed to the con- denser, where it is treated in a substantially similar manner to that in Carre's apparatus, that is to say, it is caused to liquefy under the combined action of the condensation effected by the cooling water circulating round the condenser tubes, and of the pressure maintained in the generator. The liquid ammonia (in this case practically anhy- drous) is then used in the refrigerator, and the vapour therefrom, whilst still under considerable tension, is admitted from the refrigerator to a cylinder fitted with a slide valve, and entry and exhaust ports, practically similar to those of a high-pressure steam engine, and is thus utilised to drive the force pump for returning the strong solution to the generator, after which it is passed into the absorber, where it meets, and is taken up by, the weak liquor from the generator, and the strong liquor so formed is forced back into the generator by means of a force pump as before described. The temperature exchanger or economiser introduced by Mort in* 1870 provides for the hot liquor on its way from the generator to the absorber giving up its heat to the cooler liquid from the absorber on its way to the generator, thereby saving the abstraction of so much heat from the generator, and admitting of the liquid in the absorber being kept at a lower temperature, which is of great importance to the economical working of the apparatus. The invention which Harry Frank Stanley patented in 1875 com- prises several important improvements upon the foregoing, the chief of which are as follows : In place of applying fire heat to the generator, as had been hitherto customary, a coil of steam pipes is employed for evaporating the 182 REFRIGERATION AND COLD STORAGE. ammoniacal vapour. The advantages derived from this are that the pressure and temperature in the generator can be much more easily regulated, and, moreover, the ammonia separates from the water better at a low heat, and an even temperature is found to be most essential to the efficient working of the apparatus. The steam-heated evaporating pipes consist of a number of straight pipes connected together by bends, giving a very large heating surface, and when the exhaust steam from the engine is employed therein for heating purposes, a very great saving of fuel is effected. The analyser is placed upon the generator so as to economise space and save the connections otherwise necessary. This analyser is formed preferably cylindrical, and is fitted with a series of dishes or trays having passages so arranged that the vapour impinges on the under sides thereof, and traverses the vessel without passing through the liquid. Each of the dishes or trays is provided with an overflow pipe which is raised above the level of the bottom of the tray, so as to keep some liquid in the dish, but always below the top of the vapour outlet. As the ammonia vapour is driven off from the solution of ammonia and water, by the heat of the vapour rising from the tray below, it passes through the vapour outlets into the rectifier without going through the liquor on the tray or trays above. By this means a considerable saving of fuel is effected, as the ammonia when once separated from the water on each tray or plate is at once delivered to the rectifier. Otherwise, were this not so, water has such a strong affinity for ammonia, that the vapour which had been separated from the liquor on one plate would quickly become absorbed again by the liquor it had to pass through on the next plate. The rectifier is placed on the condenser, the two forming in fact one vessel, and the same condensing water does duty for both, the latter passing in at the bottom of the condenser where the coldest water is wanted, and up the outside of the coil into the rectifier, from which it passes to the absorber. The ammoniacal gas or vapour passes from the analyser into the top of the coil in the rectifier, which coil is fitted at intervals with pockets to carry off the water resulting from the condensation of the vapour coming from the analyser, so that immediately any such condensation occurs the liquor passes at once out of the coil, and the ammoniacal vapour does not come in contact with the water after being separated from it. By providing these pockets with cocks or valves suitable adjustments of the apparatus can be effected. THE ABSORPTION PROCESS OR SYSTEM. 183 The ammonia gas thus passes to the condenser in a practically anhydrous condition, which is absolutely essential to the economical working of the apparatus, and which would not otherwise be the case, as if the gas comes into contact with the water resulting from its condensation it would reabsorb a portion of it. The condenser coil is contained in a cast or wrought iron cylinder, and to simplify the apparatus and to save space, the condenser is placed upon the receiver, the latter being a plain wrought or cast iron vessel serving, as before, to store the anhydrous ammonia before it goes into the cooler or refrigerator ; it is fitted with a glass gauge, or a float gauge, to indicate the level of the liquid therein. When the latter is employed, revolving spindles or rods working vertically through stuffing boxes in the usual way are preferably used, as tending to minimise friction and prevent leakage. The refrigerator or cooler is substantially similar to that employed in the former arrangements, but is fitted with a self-closing gauge in case of breakage. The absorber is constructed of smaller pipes or tubes, so as to enable a greater number to be used than heretofore, and thus for a given content to secure a very much larger surface exposed to the action of the cold water which surrounds the tubes ; the latter are preferably constructed of wrought iron. Another saving of condensing water is effected by having a few of the top pipes above the upper extremity of the water cistern, and letting the warm water coming from the rectifier drip over the out- side of the pipes. The heat due to the ammoniacal gas being absorbed by the weak liquor, which is given off from the inside, is sufficient to vaporise a portion of the water, and a large quantity of heat becomes latent in the vapour, producing a refrigerating effect. The pump employed for drawing the strong solution of ammonia produced in the absorber, and forcing it through the coil of pipe in the heater into the analyser, against the pressure, is so constructed that there are the very least possible clearances, and that the whole, or practically the whole contents, are discharged at each stroke, thus preventing expansion of gas on the return stroke, tending to keep the suction valves closed. The pump cocks, valves, and gauges are pro- vided with water containers, so that should any leakage of ammonia through the stuffing box occur, the water will absorb it, the latter being returned into the apparatus when it becomes thoroughly saturated. The stuffing box cock is constructed with a guard, and with an adjust- able clamp screw, which holds the key to its seat, preventing leakage 1 84 REFRIGERATION AND COLD STORAGE. from compression of the packing, and admitting of the stuffing box being repacked whilst the apparatus is at work. To allow for the gradual weakening of the solution of ammonia, a small vessel or still is provided in connection with the generator, wherein the weak solution from the latter is evaporated off at a low temperature into the apparatus, where the least pressure exists. In the invention patented by William Henry Beck, in 1886, some still further improvements in various details of construction are described, notably in the arrangement of the analyser and rectifier, and the absorber. In the first-mentioned vessel a series of sheet iron or steel trays, with or without perforations, the edges whereof are drifted or set up so as to form short adjutages, are provided. Each alternate one of these trays has a central opening, and each intermediate tray an annular space left between its circumference and the enclosing case or cylinder. An inner sheet-metal casing is, moreover, provided in which the water-separating trays are secured, and which, together with such trays, can be easily removed and replaced in position ; and the mouth of the vapour outlet pipe is sometimes surrounded by a finely perforated wire gauze chamber or guard. The absorber is formed with a primary absorbing vessel, wherein the absorption of the ammonia gas is effected to an extent dependent upon the temperature of the ordinary cooling or condensing water, combined with a secondary absorbing vessel wherein a further absorp- tion of the ammonia gas is effected by the cooling action of a current of cold brine, or of water, cooled to a temperature below that of the ordinary cooling or condensing water used in the primary absorber. The weak liquor cooler, the liquid ammonia receiver, the condenser, aud the rectifier are contained in a single open-topped tank provided with divisions or partitions so arranged as to ensure the passage of the cooling or condensing water successively through each of the compartments. Frederick Noel Mackay and Adolph Gothard Christiansen obtained a patent for improvements in ammonia absorption machines in 1887, the main features of which that are claimed as novel being as follows, viz. : The separation of the ammoniacal gas from the liquor in which it is absorbed, by boiling the liquor in stages within the same boiler. An analyser consisting of a chamber containing superimposed spirally corrugated plates having perforations or openings. The combination within one chamber of an ammoniacal liquor boiler and analyser. THE ABSORPTION PROCESS OR SYSTEM. 185 A rectifier consisting of such an arrangement of a coil or coils that the gas will take an upward direction, and the liquid a downward direction. A condenser wherein the coils are so connected that the gaseous ammonia passes from coil to coil in an upward direction, whilst the liquid ammonia flows in a downward direction. A multiple coil condenser so constructed that it has but one single through way. A rectifier and condenser consisting of chambers containing coils, all the joints whereof are situated on the exterior. An auxiliary cooler composed of a chamber fitted with a coil and regulator, and suitable connections. A vaporiser and refrigerator wherein the brine flows through a chamber, whilst the liquid ammonia expands through small perfora- tions or apertures into tubes contained in this chamber. An absorber constructed with a concentric corrugated chamber. Ammonia pumps provided with a chamber through which ammonia liquor from the absorber passes. An arrangement whereby ammoniacal liquor from the absorber is caused to cool ammoniacal liquor from the boiler. In Edward Henry Tompkins' patent, which was granted in the latter part of 1887, for improvements in refrigerating apparatus of the kind or class for which previous letters patent were granted to Rees Reece and William Henry Beck, the chief novel points claimed are : The placing of the generator within the boiler so as to secure the full efficiency of the heat given off by the steam generated therein. The combination and connection with the main gas pipe from the generator of a vessel doing the triple duty of heater, rectifier, and analyser ; which vessel consists of an iron tank with an arrangement of tubes, and a sealed joint or joints at the base through which the gas rises. An improved form of condenser, consisting of an ordinary condenser of the multitubular pattern, wherein the tubes are passed through a tube plate and expanded in the usual manner, but having in addition horizontal partition plates of metal at the alternate ends of the tubes, whereby the ammonia is caused to travel backwards and forwards along the alternate layers or sets of tubes, and thereby to receive the full benefit of the cold of the condensing water. By the removal of the end covers, moreover, each layer or set of tubes is rendered readily accessible for cleaning or repairs. 1 86 REFRIGERATION AND COLD STORAGE. A cooler or refrigerator comprising a system of horizontal tubes placed in a large tank, within which latter a solution of chloride of calcium is caused to circulate so as to secure an equable temperature throughout the entire length of the tank. An absorber, wherein provision is made for intimately mixing the ammonia gas from the refrigerator or cooler with ammonia liquor, cooled, firstly, by passing it through a small cooler, and secondly by bringing it in contact with a series of tubes through which water is made to circulate, thereby effecting a considerable gain in the working of the apparatus. An ammonia pump provided with a stuffing box wherein is inserted a hollow steel or iron ring of suitable dimensions, to which ring is connected a pipe leading to a receiver having a glass gauge to show the height or quantity of liquor ammonia which has escaped past the first series of packing, and is contained therein. From this receiver a pipe fitted with suitable stop-cocks or valves leads to a small hand- force pump or compressor of the ordinary type, so that by opening and closing these stop-cocks the escaped liquor can be withdrawn into the pump or compressor, or forced back into the generator, as may be desired. The provision of means whereby the ammonia liquor from the absorber is passed through a coil contained in the compound vessel doing triple duty as heater, rectifier, and analyser, and consequently enters the generator at a high temperature, and the temperature of the ammonia gas on its way to the condenser is likewise reduced. The condensation from this ammonia gas which occurs in the rectifier and analyser is conveyed back to the generator by gravitation ; the above-mentioned compound or triple vessel being situated above the level of the generator, and the pressure in both vessels being equal. A small cooler wherein the weak liquor ammonia coming from the generator in its heated condition is reduced to a state of comparative coolness by contact with tubes cooled by a circulation of cold water, to which water may be added, if required, waste ice to increase its cooling capacity. The advantage claimed for thus reducing the temperature of the weak ammonia solution is that its power of absorbing the ammonia gas from the cooler or refrigerator is thereby greatly increased. The patent granted to Edmund Lionel Pontifex in 1887, subse- quently to both those just mentioned, for improvements in cooling and refrigerating machines of the class described in the specification of THE ABSORPTION PROCESS OR SYSTEM. 187 former letters patent granted to H. F. Stanley in 1875, lays claim to the following : The method of mounting the condenser coils upon brackets pro- jecting inwards from the side of the cistern, and retaining them in position by means of uprights extending vertically from these brackets ; some of which uprights are extended above the tops of the condenser coils for the purpose of supporting the rectifier coil, and also for carrying a vertically arranged cylinder occupying a space in the centre of the rectifier coil, and extending to above the level of the overflow from the cistern. The object of this cylinder is to ensure that the cooling water, that rises up through the cistern, should flow only through the annular space or clearance situated between the exterior surface of the cylinder and the inner surface of the cistern, and thus cause it to act in a more efficient manner to cool the rectifier coil which is contained in this space or clearance. An arrangement for ensuring a uniform action taking place in all the concentric coils of the condenser, and causing the liquid coming therefrom to be of the same temperature, consisting in spacing the outer coils vertically further apart than the inner coils, so that the increased diameter of the outer coils is compensated for by the greater number of the inner coils. To provide for the more perfect regulation of the admission of the anhydrous ammonia liquid to the cooler, which requires very fine or minute adjustment, a stop-cock is provided with a plug through which, in addition to the way or passage which is usually formed therein, there are, at the sides of this way or passage, other narrow passages which, when the stop-cock is partially turned on, allow of a small and easily regulated quantity of liquid or fluid being permitted to pass ; whilst, on the other hand, it likewise admits of a large volume of the liquid being allowed to pass quickly, whenever the cock is turned full open, as is sometimes necessary for the purpose of clearing the small passages by blowing out any obstructions which may lodge therein and tend to choke them. The ensurance of a more effective absorption of the gas, by so arranging the absorber that the weak ammonia liquor or solution is made to fall in the form of a shower on to the surface of a tray, which latter is provided with small holes or perforations arranged in concentric circles. Through these holes the weak ammonia liquor percolates or drops down on to the tops of the coils of cooling pipes, trickling slowly from coil to coil until it reaches the bottom of the absorber, from which latter it is sucked by the ammonia pump through i88 REFRIGERATION AND COLD STORAGE. a pipe fitted at its inlet end or extremity with a perforated strainer or guard, in order to prevent the ammonia pump suction pipe from becoming accidentally choked or stopped up by any foreign bodies. In order to enable the interior of any of the coils of pipe in the absorber being readily cleared of any deposit, suitable means are provided for admitting of a pump cylinder being easily attached to the outlet of each of the coils. This cylinder is fitted with a piston which, by means of a piston rod extending therefrom, can be jerked Fig. 107. -Pontifex-Wood Improved Continuous-Acting Ammonia Absorption Machine. or moved suddenly and violently to and fro, whilst the cooling water is flowing through the coil. The shock thus caused liberates any scale that may have become deposited inside the coil, and this scale is carried off by the flow of the condensing or cooling water. The Pontifex ammonia absorption machine has been further improved by Wood, and the Pontifex-Wood apparatus, as at present constructed, is probably as near to perfection as can be attained in machines of this class. THE ABSORPTION PROCESS OR SYSTEM. 189 Fig. 107 is a perspective view, showing the elevation and general arrangement of a machine of the Pontifex and Wood type, which com- prises a generator, a separator, a condenser, a refrigerator, an absorber, and an economiser, all of which are fitted with the latest improvements. Referring to the illustration, A is the generator, B is the separator, c is the condenser, D is the refrigerator, E is the absorber, and G is the economiser. H are the ammonia pumps, the construction of which will be more clearly understood from the enlarged views, Figs. 108 and 109. ' Figs. 108 and 109. Pontifex- Wood Improved Ammonia Pump. Elevation and Vertical Central Section. The generator A consists of a horizontal cast-iron cylindrical vessel, containing a coil of steam pipe adapted to be heated by direct or live steam from the ordinary steam boilers, and into which the charge of commercial ammonia is inserted. The separator B, which is connected to the top of the generator by suitable flanges, and arranged vertically, and at right angles to the latter, is so constructed that any aqueous vapour that rises with the vaporised or gasified ammonia from the generator will be arrested or 190 REFRIGERATION AND COLD STORAGE. trapped by a suitable arrangement of baffles or checks, and is returned into the generator ; the practically anhydrous ammonia passing through a pipe from the top of the separator to the condenser c. In the condenser c, which consists of a number oi coils of pipes inclosed in a wrought-iron vertical cylinder which is constantly kept full of cold water in circulation, the anhydrous ammoniacal gas or vapour is condensed and liquefied by the pressure caused by its own accumulation. The liquid ammonia, which leaves the condenser at a temperature of between 70 and 80 Fahr., next passes into the cooler or refrigerator D, which is a vertical cast-iron vessel fitted with coils of wrought- iron pipes, through which a circulation of water or brine is kept running. In this cooler or refrigerator the liquid ammonia instantly expands, and again takes the form of gas or vapour. During this expansion its sensible heat becoming latent, "as already stated, its temperature is reduced instantly to from 10 to 20 Fahr., or considerably lower if required, and the water or, where employed for ice-making, the brine is reduced or cooled down to any predetermined temperature. After performing its cooling office in the refrigerator D the ammonia gas or vapour is led through another pipe into the absorber E, wherein it comes into contact with, and is taken up and absorbed by, the water from which it was first eliminated in the generator A, the strong solution thus formed being drawn off by the ammonia pumps H and forced back through the economise!- or heater G (wherein its tempera- ture is raised by the water which is passing from the generator into the absorber) into the generator A to be re-evaporated. The improved ammonia pumps, as shown in Fig. 107, are mounted in A-shaped frames, and when employed with a brine circulation, a brine pump is also attached to the outside of one of the A frames, and is driven by means of a disc crank fixed upon the shaft carrying the eccentrics for working the ammonia pumps. One of the ammonia pump cylinders is shown in side elevation and vertical central section in the enlarged views, Figs. 108 and 109. As will be clearly seen from the sectional view, Fig. 109, the pump is of the piston type and double-acting. A great advantage in having two ammonia pumps is that they can be so arranged that, if necessary, one of them can be shut off for repairs or overhauling, whilst the other is continued in work. The method of working the Pontifex-Wood improved ammonia absorption machine is as follows : All connections being properly made, and the generator filled or THE ABSORPTION PROCESS OR SYSTEM. 191 charged with the ordinary ammoniacal liquor of commerce, up to the proper level, as indicated by the gauge attached thereto, a little steam is admitted to the coil of pipes inside the generator, so as to raise just sufficient pressure of gas or vapour to expel all the air from the apparatus through an escape valve provided for that purpose in the absorber. , As soon as all the air is thus expelled, the full pressure of steam is turned on to the heating coils in the generator, and the ammonia in the solution, being extremely volatile, is instantly driven off in the form of gas or vapour, and passes up through the separator, where any aqueous vapour is arrested, and returned to the top of the condenser ; the aqueous portion of the ammoniacal solution remaining behind in the generator. The condensing water is admitted at the bottom of the condenser and is taken off at the top, the ammoniacal gas or vapour taking the opposite course, and passing downwards through the coil of pipe therein, the upper portion of which coil is provided at intervals with traps or pockets, and is known as the rectifier. During its passage through this coil the gas, or vapour, is reduced in temperature by the condensing water, and any watery particles that may have escaped the separator, and been carried over with .the ammonia, are caught in the above-mentioned traps or pockets, and are immediately passed out of the coil and returned into the separator, through the connection shown in the drawing. After passing the lowermost trap or pocket the ammoniacal gas or vapour is quite dry or anhydrous, and it is the practically perfect reduction thereof to this condition that constitutes the chief advantage of the Pont if ex- Wood improved machine. The dry or anhydrous ammoniacal gas or vapour now continues to descend the coil in the condenser, until, by reason of its accumula- tion, it reaches a pressure at which it becomes liquefiable, the lique- faction being greatly forwarded by the reduction of temperature effected in the condenser by the constant circulation of the cooling water. The apparatus is so constructed and regulated that, as the gas or vapour becomes liquefied, the product of liquid anhydrous ammonia passes into the refrigerator, wherein if vaporises at the ordinary atmospheric pressure at a temperature as low as 28 Fahr., and at the moment it thus changes its form it absorbs and renders latent a very large amount of heat, as has been already mentioned. The water or other liquid to be cooled is passed direct through the coil arranged in the refrigerator ; or, where ice-making is carried out, a strong solution of chloride of calcium or brine is passed through 192 REFRIGERATION AND COLD STORAGE. it, cooled to the requisite low temperature, and pumped into the ice- making or freezing tanks. The ammonia, which has now again assumed a gaseous form, passes from the top of the cooler or refrigerator into the absorber, which latter is connected to the bottom of the generator, through a suitable pipe, the pressure in the latter forcing a constant stream of the water left in it at starting into the absorber, where this weak solution greedily absorbs or takes up the gas coming from the refrigerator, and the strong solution thus formed, which is similar to that first placed in the generator, is drawn off by the ammonia pumps. The strong rich solution is then forced through a coil of pipe in the economiser or heater into the top of the separator, wherein it passes down through a succession of trays, which latter are heated by the hot vapour or gas ascending from the generator, and the ammonia is once more separated from the water in which it is dissolved, the solution gradually becoming weaker, until it finally falls back into the generator almost entirely exhausted of ammonia. As in Carre's apparatus, the complete process forms, it will be seen, a continuous closed cycle, the changes from liquid to gas and vice versa being constantly repeated. Theoretically the only outlay for working the machine, outside the small amount of oil required for lubricating the moving parts and the labour, is that entailed for the coal or other fuel consumed in raising steam for heating purposes, where exhaust or waste steam is not employed, and for supplying the small steam engine requisite to drive the ammonia pumps ; in cases, however, where water has to be paid for, there is an additional outlay for the water that is used for con- densing and other purposes. The boiler power required, where direct or live steam is used, varies from 2 H.P. in the smaller machines, which are capable of performing work equal to the reduction of 225 gals, of water 10, or of 60,000 cub. ft. of air 20 Fahr. per hour, or of an ice equivalent melted per twenty-four hours of 1J tons; up to 15 H.P. in the larger sizes adapted to so treat 8,000 gals, of water, or 1,900,000 cub. ft. of air, or of an ice equivalent in tons melted per twenty-four hours of 50 tons. In like manner the indicated horse-power that is necessary for driving the ammonia pumps will run from one, in the small machines, up to six in the larger sizes; and the amount of condensing water at 50 Fahr. from 100 to 3,000 gals, per hour. In practice a certain amount of the ammonia is always unavoidably lost by leakage, even under the most favourable circumstances. The THE ABSORPTION PROCESS OR SYSTEM. 193 amount of ammonia that thus goes to waste and has to be replaced depends chiefly upon the care taken in packing the ammonia pumps, but under average conditions it usually varies from 240 to 400 Ibs. per annum. The price of the ordinary commercial liquor ammonia used in the machine is from 3d. to 4d. per Ib. In some exceptional cases, however, machines have run in a satisfactory manner for two or three years without any additions of ammonia having been made. Other refrigerating machines acting on the above principle, of which mention may be made, are those of Hill, Seeley, and another one of French origin. A number of British patents have been obtained by Frederick Barker Hill, both singly and in combination with others, for improve- ments in ice-making and refrigerating machinery. No. 3,427 of 1876, Nishigawa and Hill; No. 6,808 of 1885, Hill and Gorman; and No. 15,914 of 1886, Hill and Gorman, claim certain improvements in absorption machines, the latter patent comprising mainly improved means for heating the ammonia boiler and for the formation of cold stores for refrigerating purposes. Hill, No. 13,487 of 1887, describes a refrigerating machine with mercurial pump, wherein mercury is employed for drawing air or other gas or vapour into and discharging it from one or more chambers. It is stated that the mercury acts as a seal to close the aperture of the suction pipe, and that, consequently, Ihe use of a suction valve can be dispensed with. This pump may be adapted for use with an apparatus such as described in the previously mentioned patent. No. 17,071 of 1888, Hill and Sinclair, contains a description of a refrigerator or ice-making machine mounted upon road or travelling wheels, and provided with suitable means whereby motion may be transmitted to its driving shaft from one of the wheels during trans- port. No. 20.811 of 1889, Hill and Sinclair, contains certain improve- ments in the absorption machine described in No. 15,914 of 1886. The ammonia boiler or still is formed in this case of two horizontal tubes connected by suitable pipes which extend longitudinally within the tubes. The horizontal parts of the pipes are perforated at their upper sides to ensure uniformity in the action of the apparatus. In combination with the refrigerating apparatus are employed two slabs or tables formed of metal or other suitable material of good thermal conductivity, beneath which circulates brine or other non-congealable liquid for conveying the cold from the refrigerating tubes or chambers to the slabs or tables. These cold slabs or tables are adapted for facili- 194 REFRIGERATION AND COLD STORAGE. tating and expediting the manufacture of chocolate, confectionery, pastry, and other substances which are formed in moulds, and which can be manipulated upon the slabs or tables. Hill, No. 16,253 of 1889, describes an improved refrigerating and ice-making machine, adapted to work on the intermittent ammonia- absorption process. The main features of the invention consist in the production of cold by this method, wherein impoverished ammoniacal liquor from the ammonia boiler is caused to pass into one or more supplementary or auxiliary absorbers, in which the ammoniacal gas is subsequently absorbed, and from which the liquor, together with the gas absorbed thereby, is then returned to the ammonia boiler. In ammonia-absorption refrigerating and ice-making machines as constructed before the date of this invention, it was necessary, after the distillation of the ammonia, to reduce the temperature of the liquid in the boiler until the pressure became sufficiently diminished to permit the vaporisation of the liquid ammonia in the refrigerator, and until the liquid in the boiler was sufficiently cool to permit the absorption of the ammoniacal gas thereby. This cooling of the liquid necessarily occupied a considerable space of time. Besides, in many of these re- frigerating and ice-making machines the absorption of the ammoniacal gas took place only at the surface of the liquid in the boiler, and was necessarily a slow process, the liquid being of higher temperature at the surface than at any other part thereof, and having its temperature raised at the surface by the condensation of the gas. The inventor claims to have discovered that, by employing one or more separate or auxiliary absorbers, which can be put in communica- tion with the boiler, the cooler or condenser, and the refrigerator as required, and in which the ammoniacal gas can ascend through a body of liquid, he can very rapidly diminish the pressure in the ammonia boiler by absorbing the gas from the boiler, the rectifier, and the con- denser in the absorber or absorbers ; and is enabled to effect the absorption of the ammoniacal gas from the refrigerator, either in the supplementary or auxiliary absorber or absorbers or in the boiler, immediately or very soon after the distillation, thus greatly expediting the production of cold by the machine. Fig. 110 is a front view partly in section, and Fig. Ill is an end view of Hill's refrigerating apparatus provided with a supplementary or auxiliary absorber. A indicates the ammonia boiler, B the separator or rectifier, c the cooler^or condenser, and D the refrigerator. E is the supplementary or auxiliary absorber, which is connected with the boiler A, the condenser THE ABSORPTION PROCESS OR SYSTEM. 195 c, and the refrigerator D by pipes p, r 1 , F 2 , P 3 , fitted with stop-cocks or valves G, G 1 , G 2 , G 3 . By the manipulation of these cocks as may be required, the impoverished ammoniacal liquor from the boiler may be introduced into the absorber E after the distillation of the ammonia, and the liquid charged with gas by absorption may be caused to return from the absorber to the boiler. Thus when the liquid anhydrous ammonia has been collected in the refrigerator D, the cocks G 2 , G 3 , are closed and the cocks G, G 1 partly opened, so as to admit of the weak or impoverished solution from the boiler A, or a sufficient portion of it, being forced into the absorber E ; the cock or valve G 1 is then closed, I r t a Figs. 110 and 111. Hill's Ammonia Absorption Machine with Supplementary or Auxiliary Absorber. Diagrams showing Front and End Views. and the cock G 2 is opened to rapidly relieve the pressure in the con- denser, rectifier, and boiler, by allowing the gas therefrom to become absorbed by the weak solution in the absorber E. As soon as the solution in the boiler is sufficiently cooled to permit reabsorption of the gas thereby, the boiler is placed in communication with the refrigerator by opening the cocks or valves G 1 , G 3 . The ammonia solution from the absorber E will be returned by gravity or in any other convenient manner into the ammonia boiler A, through the cocks G, G 1 , when required. Instead of placing the refrigerator D in communication with the boiler A, it may be so connected with the supplementary or auxiliary 196 REFRIGERATION AND COLD STORAGE. absorber E, thereby permitting the vaporisation of liquid ammonia in the refrigerator, and the absorption of the ammoniacal gas by the impoverished ammoniacal liquor previously introduced into the absorber E from the ammonia boiler. While the vaporisation of the ammonia in the refrigerator is thus proceeding, the weak solution in the ammonia boiler may be cooled, after which the refrigerator may be put into communication with the ammonia boiler. In Fig. 112 is shown a complete machine constructed on the fore- going principle. L is a coil boiler for heating the solution in the ammonia boiler A, with which the coil boiler is connected through the medium of a separator M. The type of absorption machine made by the Henry Vogt Machine Fig. 112. Hill's Ammonia Absorption Machine, with Supplementary or Auxiliary Absorber. Diagrammatical View of Complete Machine. Co., of Louisville, Ky., U.S.A., has no round coils and bent pipes. The generator operates on the fractional distillation principle, and is claimed to produce practically anhydrous ammonia. It consists of a main casting divided into four compartments communicating the one with the other, and four horizontal pipes connected to the main casting, which contain the steam heating coils. The highest compartment of the main casting is connected to a stand-pipe containing an analyser and rectifying coil by which the gas is dried before it leaves the still. The strong liquor is passed in at the top of the stand-pipe, and descending through the rectifying coils and the analyser reaches the upper compartment of the main casting, from which it flows over the steam coil in the horizontal pipes, passing from one to the other until THE ABSORPTION PROCESS OR SYSTEM. 197 the lowermost compartment is reached. The gas that is generated is delivered through the aperture in each compartment to the stand- pipes, where it deposits its moisture, and the dried gas goes on to the condenser. The heat exchanger or economiser consists of an arrangement of straight concentric tubes, the outermost of which are connected at their alternate extremities by H -shaped pieces, and the inner ones being coupled together by external bends also acting as glands to the joint- ing. The strong ammonia liquor enters the heat exchanger at the bottom on its passage to the still or generator, and is delivered out at the top. The weak liquor from the still or generator on the other hand enters the heat exchanger at the top, and leaves it at the bottom. A double-acting horizontal fly-wheel pattern pump, running at a speed of twenty-five revolutions per minute, is employed, the special feature of which is the construction of the ammonia stuffing box with a surrounding water chamber, which acts as a lubricator to the piston rod. The absorber is constructed in the form of an upright tubular boiler open at the top, the tubes being uniformly distributed, and so arranged that they can be cleaned whilst the machine is running. The cooling water is admitted at the bottom, and passes out at the top, an automatic regulator controlling or governing the flow. The type of absorption machine made by the Ice and Cold Machine Co., of St Louis, Mo., U.S.A., is a modification of the Carre apparatus by Mr Ball. The generator is constructed of steel and is of a vertical cylindrical form, having a removable top head, steam heated, and with drying trays or pans arranged in the gas dome. An open-air or a submerged type of condenser is employed in accordance with the water supply. The heat exchanger or equaliser is a cylinder fitted with removable heads containing tubes. From the shell of this heat exchanger the poor liquor passes to the coils of the poor liquor cooler, which is also either of the submerged or open-air surface evaporative type, and thence to the absorber. The gas liquefied in the condenser tubes passes through the expan- sion valves to the expansion or evaporating coils in the freezing tank, and it returns from thence to the absorber. This latter apparatus is a cylindrical-shaped vessel fitted with vertical tubes, up through which the water passes, removing the heat from the ammonia. The ammonia is raised by two single-acting vertical pumps driven by a vertical steam engine, to which they are directly coupled. These 198 REFRIGERATION AND COLD STORAGE. pumps lift the enriched ammonia from the absorber through the exchanger tubes into the top of the generator, and thus complete the cycle. To dry the gas and separate any moisture therefrom the air-blast is maintained at a temperature of 14 below zero Fahr., and the temperature of the ice-making box or tank is from zero to 2 Fahr. Fig. 113. Tyler & Ellis' (Cracknell's Patent) Ammonia Absorption Machine. Front View. Fig. 113 is a front view, Fig. 114 is a side view, and Fig. 115 is a vertical longitudinal central section through either side of Fig. 113, showing Cracknell's patent ammonia absorption machine, formerly made by the Tyler & Ellis Mfg. Co., Ltd., subsequently by Ransome & Rapier. Ipswich, and known as the " Simplex." The machine consists essen- tially of two vessels (A and B), one of which vessels (say B) contains strong anhydrous ammonia liquor, and is heated by a steam coil, whilst the THE ABSORPTION PROCESS OR SYSTEM. 199 Fig. 114. Tyler & Ellis' (CracknelFs Patent) Ammonia Absorption Machine. Side Elevation. other vessel A is filled with the spent liquor from the last operation, and is cooled by a water coil. Ammonia is given off in B under considerable pressure, and passes through the valve to the condenser, where, becoming cool, it condenses or liquefies, and passes to the expansion valve as liquid anhydrous ammonia. After getting by the Fig. 115. Tyler & Ellis' (Cracknell's Patent) Ammonia Absorption Machine. Vertical Longitudinal Central Section. 200 REFRIGERATION AND COLD STORAGE. expansion valve, which latter is regulated to pass the liquid according to the amount of heat to be abstracted, or cooling to be performed, the pressure disappears, and the liquid ammonia rapidly evaporates as it traverses the succeeding pipes and coils, producing a large volume of gas of an intense cold. After traversing the cooling coils in the evaporator or refrigerator the gas returns to the machine through another valve, where it meets the weak liquor in the vessel A, and is absorbed by it. This process continues until the charge in B becomes spent, and that in A concentrated, when the valves I and N must be closed, the valves L and K opened, the reversing handle T turned towards D, and upon the equalising of the pressure on the two gauges Fig. 116. Lyon's Patent Ammonia Absorption Machine. Plan. the valves L and K should be closed, the valve J opened, and, as soon as the pressure falls below 30 Ibs. on the pressure gauge on A, the valve M should be also opened. The effect 'of this will be to exactly reverse the order of things, A then becoming the high pressure or hot side, and B the low pressure or cool side. Each of these operations will average about an hour. Fig. 116 is a plan, Fig. 117 is front view, and Fig. 118 is a vertical longitudinal section illustrating a small refrigerating machine, on the absorption system, designed by Mr Lyon, of Glasgow. The illustra- tions, as well as the following description, are taken from his patent specification. G is the generator, and A is the absorber, both of which are hori- THE ABSORPTION PROCESS OR SYSTEM. 201 zontally placed cylindrical vessels, the absorber being located at a higher level than the generator. Heat is applied in the generator G, through a pipe s, through which steam is passed, or an electric heater or other known heating appliance may be used ; and the vessel is encased in a shell packed with a material H which is a bad conductor of heat. The upper part of the generator G is connected by a pipe B to the lower part of a vessel E, termed a rectifier, which is kept at Fig. 117. Lyon's Patent Ammonia Absorption Machine. Front Elevation. a moderate temperature by a water jacket J, and in which ammonia vapour entering it from the generator G separates from traces of water which return to the generator. From the rectifier R the ammonia vapour passes through a pipe D to a worm or other condenser c, in which it is acted on by cold water so as to become cooled and liquefied. The ammonia thus condensed and liquefied is employed in the ordinary way so as by its expansion in tubing T, indicated by dotted lines, immersed in brine in a tank u, to produce refrigeration, the 202 REFRIGERATION AND COLD STORAGE. ammonia proceeding from the condenser c by a pipe v, having on it a regulating or expansion valve w to the expansion tubing T. From the expansion tubing the ammonia vapour passes by a pipe x into the absorber A, which is provided with an internal pipe coil Y, and with an external jacket z, through which cold water is passed. On starting the machine the absorber A will be partly filled with water or with a weak solution of ammonia, there being then in the generator G a strong solution of ammonia. During the operation the solution in the generator G becomes weakened because of the evapora- tion of the ammonia, whilst that in the absorber A becomes strengthened by absorbing ammonia vapour from the expansion tubes T ; and when Fig. 118. Lyon's Patent Ammonia Absorption Machine. Vertical Longitudinal Section. the operation has been continued as long as is desirable, the strong solution in the absorber is run through a stop-cock E and pipe F into an intermediate vessel I. Then there is opened a stop-cock K on a pipe L, which extends from the absorber A down to the lower part of the generator G, whereupon, owing to the excess of the pressure in the generator over that in the absorber, the weak solution in the former is transferred to the latter. Finally a stop-cock M in a pipe N, con- necting the intermediate vessel i with the generator, is opened, and the strong solution is run into the generator ready for a fresh operation. For the purpose of equalising the pressure, the intermediate vessel i has connected to it a pipe a, with branches b, c, connected to the absorber A and to the generator G, the branches having stop-valves d, e. THE ABSORPTION PROCESS OR SYSTEM. 203 Thus when the solution is being transferred from the absorber A to the intermediate vessel i the upper valve d is opened, the lower one e being closed, and when the solution is being transferred from the intermediate vessel i to the generator c, the upper valve d is closed, and the lower one e opened. An ammonia absorption machine designed by Mr C. Senssenbrenner, a German inventor, and shown in Fig. 119, has an evaporator a com- municating, with the condenser d through an opening e. The condenser Fig. 119. Senssenbrenner Patent Ammonia Absorption Machine. Fig. 120. Diagram illustrating Coleman's Electrically-heated Absorption Machine. is fitted with a cooling receptacle " Dry Cold- Air Machine. (For Data of Test see page 244. ) Fig. 138. Indicator Diagram from Single-Acting Expander of "Arctic" Dry Cold- Air Machine. (For Data of Test see page 244. ) cylinder Q for driving purposes, a compression cylinder R, in which the air is compressed to about three times its primary pressure, which cylinder is water-jacketed to prevent injury to the piston packings from the heat engendered by this compression. A copper coil s, immersed in a water bath, into which coil the compressed air is passed and cooled, or reduced to the temperature of the cooling water. A return air-cooler T, by means of which the compressed air is further cx>oled by the cold air returning from the cold storage chamber. An expansion cylinder v, wherein the cooled compressed THE COLD-AIR SYSTEM. 239 air is allowed to expand to one-third of the tension of compression, that is to say, to its original pressure, on entering the compressor cylinder, during which operation it is cooled as much as it was previously heated by the compression, and leaves the cylinder at a very low temperature. This cooled air is then discharged into a well-insulated pipe, by means of which it is conveyed to the place which it is desired to cool. Here the pipe service is left exposed ; that is to say, it is not insulated, and the cold air, after taking up the heat from the surrounding matter, is again returned RETURN AIR AUCTION Fig. 139. Allen Dense-Air Ice Machine. Diagrammatical View. to the compressor, where it is again subjected to compression, cooled, and expanded as before. A suitable trap or separator, as indicated at v, is also provided for eliminating the lubricating oil used in the cylinder, as well as any snow that may be former 1 , Lorn the cold air. The deposits are removed from this separator by heating the latter through a suitable steam pipe, and running off the contents through a drain pipe and cock, the machine being so arranged that any frozen deposits from the expansion cylinder will be at the same time thawed and blown out into the separator. In operation the separator requires blowing out once or twice in every twenty-four hours. 240 REFRIGERATION AND COLD STORAGE. Cooling water for the separator, the copper air-cooling coil bath, and the water jacket round the compression cylinder, is supplied by an ordinary plunger-pump w, and a small supplementary air-pump x is also provided for charging the system when starting with air up to the necessary pressure, and also for making up any losses that may occur by reason of leakage through stuffing boxes and joints whilst the machine is running. To extract the moisture from this fresh supply of air to the system it is passed through a drier or separator Y, by means of which it is dried as far as practicable before entering the machine, z is a safety valve. The operation of the apparatus is as follows : The normal pressure of the air in the system is 60 Ibs. per square inch, and this air is compressed in the compressor to 210 Ibs. per square inch. Should it be found impossible to keep up these relative pressures of 60 Ibs. on the suction side and 210 Ibs. on the discharge side, it is a sign of leakage. The oil trap or separator being choked by congealed oil or snow, or the closing of valves will likewise cause a disturbance in the pressures. It will be seen that the air is in this machine used in a closed cycle. The compressed air from the compression cylinder is cooled, expanded down to its original pressure of 60 Ibs. per square inch whilst doing work, and the resultant cold air at a temperature of about 60 below zero Fahr. is forced through the refrigerating or cooling pipes, where it takes up the heat from the surrounding objects, and is again returned to the compression cylinder to be compressed, cooled, and expanded, and so on ad infinitum. It is claimed for this machine that by maintaining the air at a constant pressure of five atmospheres (60 Ibs. gauge pressure) it can be conveyed in pipes of comparatively small diameter, and the rise of temperature will be slight. No absorbed water vapour has to be cooled from the vapour to the frozen condition, and the greater- efficiency of the dense air or air under pressure enables a very much smaller machine to be used than would be the case with an ordinary cold- air machine for the same capacity. The only additional moving part in the Allen dense-air ice machine is the small auxiliary or primer pump which is a simple plunger-pump of ordinary construction. There are also the closed refrigerating pipe system, and the two traps by means of which the lubricating oil and water are removed or eliminated from the air, and the latter is maintained in a pure condition whilst passing through the pipes. THE COLD-AIR SYSTEM. 241 It will be obvious that the refrigerating or cooling pipes will be arranged in the cold storage room or chamber in a similar manner to those of any direct expansion ammonia plant. As no chemical circulating agent or medium is employed, the items of expense com- prise only the steam consumed in the driving engine or motor, the necessary lubricating oil, arid the labour of attending to the machine, which the makers state are small. The efficiency of dense-air machines is low, and as compared with ammonia compressors, they consume from ten to fifteen times the horse-power. Dense-air refrigerating machines have been used to some extent on board warships belonging to the United States owing to the immunity from danger in case of leakage. In a paper* on "Refrigerating Machines," by Arthur Robert Gale, C.E., the author makes the following observations on refrigerat- ing machines of the cold-air type : " One of the chief difficulties in cold-air machines is the presence of moisture held in suspension by the atmosphere; this applies especially to the open cycle machines. Moisture in the air occasions loss of efficiency in two ways. If the air enters the expansion cylinder in a saturated condition, when the air is cooled by expansion whilst performing work, a certain amount of vapour is condensed and thrown down the point of saturation being dependent on the temperature. The vapour, in changing to the liquid state, gives its latent heat of vaporisation to the air ; arid as the expansion of the air continues, and the temperature is still further diminished, the liquid freezes and accumulates in the form of snow arid ice in the valves arid passages, giving up its heat of liquefaction to the air. Thus not only does the presence of moisture in the air produce mechanical difficulties, choking the air passages and impeding the action of the valves, but, for the same expenditure of energy, the cold air leaves the machine at a higher temperature than would have been the case if there had not been a superabundance of moisture in the air during expansion. " As the cold-air machine is the direct reverse of the heat-engine, so also its conditions of greatest efficiency differ from those of the latter. The maximum theoretical efficiency of a refrigerating machine may be expressed by the formula Ha T E ~Tc-T' * Minute* of Proceeding, Inst. C.E., vol. cxviii., Session 1893-94, pp. 421 422. 16 242 REFRIGERATION AND COLD STORAGE. where E is the thermal equivalent of the work of compression, Ha denotes heat-units abstracted by the system, Tc denotes absolute temperature at which rejection of heat takes place, T denotes absolute temperature at which absorption of heat takes place. From the above it follows that v T Tc-T ^ = H rfi i.e., in any refrigerating machine the greatest efficiency will be obtained with a small range of temperature ; the greater the range the smaller the efficiency will be, other conditions being equal ; also the efficiency is increased as the lowest limit of the range of temperature is raised. Thus a machine working between the temperatures of 100 Fahr. and Fahr. would, other conditions being unaltered, be more efficient than when working between 60 Fahr. and - 40 Fahr. These remarks are applicable to any system of refrigeration, and are not peculiar to the cold-air machine." For some time it was very generally supposed that many kinds of provisions of a perishable nature were liable to receive damage from the snow held in suspension in the cold air from these machines, and it was this fear of injurious effects which prompted inventors to design those forms of special drying apparatus intended to remedy this defect, such as the Bell-Coleman interchanger, wherein the air is dried by passing it through a series or set of coils situated in the chamber cooled by the machine ; of the improved form of the above designed by Haslam, wherein the interchanger is cooled either by the spent cold air on its leaving the chamber wherein it has been utilised, or by the cold air as it passes out of the expansion cylinder ; the Lightfoot machine, wherein the expansion is performed in two stages ; or of Hall's centrifugal moisture separator (or the air-d^ing arrangement of T. & W. Cole). Hence the term " dry -air refrigerator." This objection to the cold-air machine arose, however, from a fault the evil effects of which, it has now become evident, have been un- doubtedly much exaggerated, as in practice no such damaging results to the contents of the stores or chambers are experienced as it was supposed and predicted would ensue, although of course the snow that is formed in the manner above described is an undeniably objec- tionable product. If a cold-air machine be worked on the principle of exclusion of the aqueous vapour, after a few cycles of operations THE COLD-AIR SYSTEM. 243 the air will have become dry, and will thenceforward work like a true gas. Owing to their compactness and simplicity, to the non-requirement of any chemicals, and to the great facility of application, cold-air machines are found to be very suitable for marine installations, and for this purpose they are extensively employed. They are also, however, in use to a considerable extent for refrigerating cold stores or chambers for the preservation of provisions of a perishable nature. An objection, however, to machines of the Bell-Coleman type, wherein the air is partially cooled during compression by the injection of cooling water into the compressor, is experienced at sea, by reason of the corroding action of the salt water, in addition to the loss of efficiency common to all machines of this class. Considerable difficulty has been experienced in tropical climates, where, with the cooling water at about 90 Fahr., the moisture-laden air would be delivered into the cooling pipes at a temperature of 95 Fahr., or more, and the absolute pressure would be about 65 Ibs. per square inch. Now, as there is, as Mr Lightfoot observes,* "precisely the same amount of dry cold air circulating outside the cooling tubes in a given time as there is warm compressed air within, it follows that by whatever amount the temperature of the internal air is reduced, by an equal amount must that of the external air be raised. But, in addition, the internal air has vapour mixed with it, which, as the temperature falls, gives off heat, measured not only by the reduction in its sensible temperature, but by the latent heat of vaporisation ; and this heat also has to be taken up by the external air. It will be found that, assuming each pound of internal air, with its proportion of vapour, to be reduced to 42 Fahr., the pound of external cold air, which has to take up all the heat due to this reduction, will be raised in temperature by 84 Fahr." This defect is obviated in machines of T. & W. Cole's "Arctic" type, as the air is cooled by their drying arrangement some 25 lower than the cooling water. Thus in tropical climates, where the cooling water would be about 90, the compressed air would be cooled down to 65, and thus be deprived of a great proportion of its suspended moisture before being admitted to the expansion cylinder. Instead of using the spent air for cooling purposes, the cold air from the expansion cylinder may be applied direct to the cooling apparatus ; but in this case difficulty would be experienced from the * Proceedings, Institute of Mechanical Engineers, 1881. 244 REFRIGERATION AND COLD STORAGE. deposited moisture inside the tubes actually freezing from the intense cold of the external air, a difficulty which, it appears, has often occurred with this apparatus. This, apart from the mere obstruction of the pipes, would involve a further sacrifice of cold, owing to the liberation of the heat of liquefaction. The following table shows the results of test experiments made with modified Giffard, Haslam, Bell-Coleman, and Cole's " Arctic " machines : Cole's " Arctic." Giffard.* Haslam.f Bell- Coleman.J No. 4 No. i Size. Size. Diameter of compression cylinder, in ins. 27 25i(2-cy.) 28 ii 6} ,, expansion ,, ,, 22 IQj 21 9 si Stroke of each 18 ^6 24 "I 2 8 Revolutions per minute .... Air pressure in receiver (absolute), in Ibs. 62 72 96 160 per sq. in 65 6 4 61 65 75 Temperature of air entering compression cylinder (containing vapour up to 88 per cent, of saturation). .... 52 F. 652 F. 48 46 Temperature of air discharged from com- pression cylinder ..... Temperature of compressed air admitted 267 F. to expansion cylinder .... 70 F. 35 Temperature of air after expansion . Work done in compression cylinder, from - 82 F. -8 5 F. -52 -81 -98 diagram 43-12 H.P. Work given off in expansion cylinder, from diagram 28 '05 H.P. Difference in work done in compression cylinder, and work given off in expan- sion cylinder ...... i5'07 Diameter of steam cylinders, in ins. . ., . trunks in cylinders, in ins. . 12 IO Stroke of trunks 15 Initial steam pressure in cylinders (abso- lute) per sq. in 55 Ibs. Work given off in steam cylinders, from diagram 24-6 H.P. Initial temperature of cooling water. 57 F. .. 62 4 1 Final i45 F. Quantity of cooling water passing per minute in lb^ Work lost in heat taken off by cooling 9 25 water 19 H.P. I. H.P. in compression cylinder ,, in expansion cylinder 43' 1 28-0 ?7?2 124-5 58-5 M'5 3-28 1-68 Per cent, of I. H.P. of compression re- turned in expander .... 51 47 54 51 * Proceedings, Institution of Mechanical Engineers, 1881. f Proceedings, Manchester Society of Engineers, 1894. Professor Schroeter, " Untersuchungen an Kaeltemaschieren verschiedener Systeme," 1881. A. J. Wallis-Tayler, 1902. THE COLD-AIR SYSTEM. 245 FORMULA FOR CALCULATING THE AMOUNT OF AIR DELIVERED PER HOUR BY COLD-AIR MACHINES, WHEN THE REVOLUTIONS AND THE SlZE OF THE COMPRESSORS ARE KNOWN. This is given as follows by Messrs Ha slam in their catalogue of ice-making and refrigerating machinery : AxNx2RxSx60 n Air discharged per hour = x U. * Where A = Area of each compressor in inches, N = Number of compressors, 2R = Strokes per minute (or twice the revolutions), 60 = Minutes per hour, S = Stroke in inches, 1,7 28 = Cubic inches in 1 ft., C = Factor of efficiency which is taken as *8 for short strokes, and '85 for long strokes. CHAPTER XI COCKS, VALVES, AND PIPE JOINTS AND UNIONS Expansion or Regulating Cocks and Valves Stop-Cocks and Valves Suction and Discharge Valves Pipe Joints and Unions Means for Increasing the Cooling Surface of Pipes. EXPANSION OR REGULATING COCKS AND VALVES. A NUMBER of cocks or valves are required on every refrigerating machine, the most important being, however, the expansion or regu- lating cock or valve, or as it is sometimes called, the flash-cock or valve, which serves to control the connection between the condenser and the refrigerator or evaporator. Fig. 140. Taper Spindle Expansion or Regulating Valve. View partly in Vertical Section. 246 COCKS AND VALVES. 247 Fig. 140 is a view partly in vertical central section, and Fig. 141 is a vertical central section showing two patterns of a very common form of expansion valve of the taper spindle type which are adapted for use with manifolds. The construction of these valves is obvious from the drawings, the taper spindles and valve boxes or casings are made of hardened steel, and whilst extremely simple in construction the type is, perhaps, all things considered, about the most effective arrangement for general purposes. Figs. 142 and 143 show in vertical central section the J-in. angle Fig. 141. Taper Spindle Expansion or Regulating Valve. Vertical Central Section. and globe expansion valves employed by the Triumph Ice Machine Company. These valves are made of the best machinery steel, and are so constructed that they can be packed at any time. The drawings are self-explanatory, as is also that shown in Fig. 144, representing a vertical central section through the Frick expansion valve, which is constructed of drop steel forgings. Fig. 145 is a plan, Fig. 146 is a vertical central section, and Fig. 147 is a view of the plug partly in vertical section through the port or way, showing the De La Yergiie improved expansion cock. 2 4 8 REFRIGERATION AND COLD STORAGE. The port or passage through the plug (Figs. 146 and 147) is so formed as to admit of the nicest regulation being effected. With this object the round hole is not carried completely through the plug, but only through about three-quarters the thickness thereof, as shown in Fig. 147, and the remaining thin bridge of metal is perforated in the shape of a very narrow wedge as shown in Fig. 146. The plug is rotated by means of a worm and worm-wheel in the manner which can be clearly seen from the drawing, and whereby Fig. 142. Triumph Angle Ex- pansion or Regulating Valve. Vertical Central Section. Fig. 143. Triumph Globe Ex- pansion or Regulating Valve. Vertical Central Section. very fine or delicate adjustment can be readily imparted thereto. The narrow wedge-shaped passage or aperture allows of the flow of the liquid ammonia being regulated to the minutest possible amount, the point or apex thereof being the first to open. The stop-cocks or valves described in a patent taken out by Puplett and Rigg in 1887 for regulating or completely cutting off or arresting the flow of the gas or liquids to the various parts of the apparatus have metal seats. To prevent leakage of the gas or liquid, the stuffing boxes of these valves are provided with screwed glands, which are likewise COCKS AND VALVES. 249 screwed on to the valve spindles, which latter are screw-threaded for their entire length, and are packed with some suitable yielding fibrous or metallic packing, such, for instance, as hemp or lead. This packing is caused to enter into the screw threads upon the spindles as the Fig. 144. Frick Angle Expansion or Regulating Valve. Vertical Central Section. glands are forced or screwed down, thus making gas-tight joints round the latter without causing the valves to set fast. A description of the Pontifex expansion or regulating valve will be found on page 187, being one of the improvements included in his 1887 patent. 250 REFRIGERATION AND COLD STORAGE. Fig. 145. Fig. 146. Fig. 147. Fig. 145. De La Vergne Expansion or Regulating Cock. Vertical Central Section. Fig. 146. Do. do. do. View of Plug partly in Section. Fig. 147. Do. do. ... do. Plan, COCKS AND VALVES. 251 A form of expansion valve for use with ammonia or other com pression machines has been designed by Suppes and Dortch of Ohio, U.S.A., which, it is claimed, obviates the formation of ice upon the exterior of the valve owing to the intense cold which is produced at this point by the expansion of the ammonia or other agent. Briefly, the expansion valve now under consideration comprises a valve and casing having a pipe member connecting the expansion orifice of the valve with the refrigerating coil, which valve is provided with an ice- guard consisting of a member of a comparatively large area secured to the exterior of the valve casing ad- jacent to the valve. This ice-guard or member performs the double office of, firstly, absorbing heat from the atmosphere, and in this manner preventing an undue reduction in the temperature of the valve casing from taking place; and, secondly, of forming a barrier over which the .MR Fig. 148. Triumph Safety Com- bination Expansion Valve and Stop-Cock. Vertical Central Sec- tion. Fig. 149. Haslam Im- proved Type of Expansion Valve. 252 REFRIGERATION AND COLD STORAGE. ice which accumulates on the pipe member must creep before it can reach that portion of the casing surrounding the valve. In Fig. 148 is illustrated the Triumph safety combination expansion valve and stop-cock. With this valve there is no necessity for pump- ing out or shutting down the plant, as it can be repaired at any time by shutting off the stop-cock, removing the stem arid inserting in its place a short plug which is sent out with each valve. Expansion can then be effected with the stop-cock, which has a V-shaped opening at both ends, so that no mistake can be made as to which direction it is Fig. 150. De La Vergne 2^-in. Stop-Cock. Vertical Central Section. turned. When the expansion valve is repaired, all that is required is to simply shut off the stop-cock again, remove the short plug, and reinsert the valve stem, after which work can be resumed as before. Fig. 149 shows the Haslam improved type of expansion valve which is especially adapted for fine adjustment. STOP COCKS AND VALVES. The De La Vergne improved form of stop-cock for ammonia gas is illustrated in Figs. 150 and 151, which show vertical central sections COCKS AND VALVES. 253 through the shells or casings of a 2^-in. and a 1-in. cock, the plugs being left in elevation. As will be seen from the drawings, the square for operating the plug is, contrary to the usual custom, placed at the small end thereof, the latter being pressed to its seat by a spiral spring inserted between its large end and a cap bolted up to the shell or casing, and having an annular projection adapted to engage in a corresponding groove formed in the latter, and wherein is provided a lead or other washer. Similar means for forming a gas-tight joint are provided at the small end of the plug, and in this manner the escape of any fluid into the chamber that might chance to pass the plug is prevented. The even and con- stant pressure of the spiral spring maintains the plug always on its seat, and prevents any grit or other impurities from getting between Fig. 151. De La Vergne 1-in. Stop-Cock. Vertical Central Section. the surfaces and cutting or abrading them. The shell of the small- sized cock or valve (Fig. 151) is of slightly modified form. The Kilbourn stop-cock is provided with a cone, gland, nut, or sleeve, and collar, so constructed and combined that by turning the gland nut in the one direction the cone will be forced into and held in its seating, whilst on the other hand by turning it in the other, or opposite direction, the cone will be started from its seating. The construction of the Triumph Ice Machine Company's stop- valve is such as to admit of its being packed at any time without running the risk of loss of gas. The valve has double seats, and the valves, when closed, clamp the seats so that it s impossible to have any leakage. The seats are formed of lead, so that should they at any time be injured by foreign matter, by simply removing the damaged 254 REFRIGERATION AND COLD STORAGE. seat and inserting a new one a new valve is secured at only the expense of a lead seat. Fig. 152 shows one pattern of shut-off or Fig. 152. Frick Shut-off or Stop-Valve. Vertical Central Section. Fig. 153. Frick Stop- Valve. Perspective View. Fig. 154. Frick Stop- Valve. Perspective View. stop- valve used by the Frick Company. Figs. 153 and 154 are two other patterns of stop-valves made by the same company. COCKS AND VALVES. 255 Fig. 155. Haslam Standard Type of Ammonia Valve for Connections over 1 in. diameter. Fig. 156. Haslam Standard Type of Ammonia Valve for Connections over 1 in. diameter. Fig. 157. Haslam Small Steel Valve for Gauge and other Connections under 1 in. diameter. 256 REFRIGERATION AND COLD STORAGE. Figs. 155 and 156 are sectional views of the standard Haslam type of ammonia valves such as are supplied for all sections over 1 in. in diameter, and are the outcome of many years' experience. The bodies of the valves are constructed of a special mixture of gun iron, the valves and spindles being of steel. A special feature of this type of valve is that the gland can be repacked at any time without possibility of loss of ammonia. Fig. 157 illustrates a small steel valve used for gauge and other connections under 1 in. in diameter. Fig. 158. Discharge Valve, Her- cules Compressor. Vertical Cen- tral Section. Fig. 159. Suction Valve, Her- cules Compressor. Vertical Cen- tral Section. SUCTION AND DISCHARGE VALVES. Compressors for ammonia or other volatile refrigerating agents are usually provided, in the case of a vertical single-acting machine,' with two valves a suction and a discharge valve at one extremity of the cylinder only ; and a double-acting horizontal machine has as a general rule four valves two, viz., a suction and a discharge valve, being located at each end of the cylinder. It is hardly necessary to remark that these valves must, like all other valves in the system, be maintained tight, but, in addition to this, these particular valves are all held against their seats by suitable steel springs ; and it is a matter of the greatest importance, as regards the securing of the utmost economy in working possible, to see that the proper amount of tension is put upon these springs. COCKS AND VALVES. 257 Should the spring governing the discharge valve of a compressor be too strong, then it is evident that an undue amount of pressure will have to be exerted in order to raise it from its seat, and hence a loss will be experienced. Still worse is it if the spring on the suction valve be over powerful, as in this event an excessive amount of suction will Fig. 160. Triumph Suction Valve. Vertical Central Section. have to be produced in order to effect the raising of the valve off its seat, thereby creating a serious interference with the flow of the gas into the cylinder of the compressor. Very sensible losses in efficiency will be experienced when the springs of both valves are exerting an over-pressure. A very small loss in the volume of gas for each single '7 258 REFRIGERATION AND COLD STORAGE. or double stroke of a compressor will in twenty-four hours amount to a serious item. The most effective method for adjusting the tension of the com- Dressor valve springs to a nicety is by the use of the indicator. In Fig. 161. Fig. 162. Triumph Pattern Suction Valves for Frick Compressors. Vertical Central Sections. Fig. 163. Fig. 164. Triumph Pattern Suction Valves for De La Vergne Compressors. Vertical Central Sections. fact, without the use of the latter instrument, it is impossible to ensure any degree of accuracy of adjustment, and consequently every compressor should be provided with proper pipes to admit of the attachment of an indicator. COCKS AND VALVES. 259 Figs. 158 and 159 show respectively the construction of the dis- charge and suction valve of the Hercules compressor. An obvious objection to the old form of construction was that on the removal of the cap the whole valve would fall into the cylinder. In the improved pattern made by the Triumph Company, this objection is obviated. Fig. 160 shows the Triumph suction valve. This valve is fitted with a guard so constructed as not to reduce the port area, which guard is attached to the lower end of the valve stem, which is enlarged for this purpose. In case of breakage, or should the stem come loose, Fig. 165. Triumph Pattern Valve for Calahan Compressor. Vertical Central Section. this guard will prevent the valve from dropping into the cylinder. By removing the hood or cap on the top of this valve, which may be done whilst the machine is in operation, the movement of the stem may be seen. This enables the person in charge to ascertain whether or not the valve is working properly. Should the suction valve become tight from some cause, or the spring be too tight, all that it is necessary to do is to remove the cap, take off the locker and turn the valve- stem to the right. If, on the contrary, the spring is too slack or light, and permits the valve to open too much, the stem should be turned to the left. After the required adjustment the^locker and cap can be 260 REFRIGERATION AND COLD STORAGE. replaced and the valve will be found to be working properly. The whole of this operation can be effected without shutting down the machine. Figs. 161 to 164 show the patterns of safety suction valves con- structed by the Triumph Company for the Frick and the De La Vergne types of compressors, and Fig. 165 illustrates the pattern of valve made by the same company for the Calahan type of machine. PIPE JOINTS AND UNIONS. An important part of a compression plant is the provision of absolutely gas-tight pipe joints, which, by the way, is by no means an easy matter to effect, at least with the agents working at the higher pressures. It is scarcely necessary to observe that the pipes must be so put up that they will be capable of expanding and contracting freely, for the range of expansion in pipes which are liable to be subjected to extremes of temperatures so widely differing as in the present case, is considerable. The pipes should likewise be fixed in sections, so that any particular portion can be removed for cleaning or repairs and replaced in position without having to interfere with the other ones. For various reasons it is impracticable to use joints screwed together with white or red lead or varnish, as in the case of steam- pipes, and consequently some other method of forming a gas-tight joint has to be resorted to. A joint which is frequently employed is a compound screwed and soldered one, and this kind of joint is found in practice to be a very durable and reliable one, being capable of with- standing the expansion and contraction to which the pipes are con- stantly liable, as well as the periodical rapping to which they are subjected during cleansing operations. The leading features of all joints of this description is the commencement of the female screw thread in the socket a short distance from the extremity of the pipe or fitting, the intermediate portion being slightly enlarged so as to form an annular space or clearance, when the spigot end of the pipe is in position, adapted to receive the solder. A method of forming gas-tight joints, for use wherever the end of a coil or of a pipe is to be secured to the sides or ends of any of the chambers, invented by Pontifex in 1887, is as follows: A nut is screwed on to the pipe on either side of the plate, and on one or both sides of the plate a circular recess is formed around the pipe. Into this recess, and around the pipe, is inserted a packing PIPES AND JOINTS. 261 ring or insertion of india-rubber or of any other suitable material, which ring is circular in transverse section. The nut screwing on the pipe is likewise shaped circular at one end so as to enable it to enter and fit into the recess, or in some instances a washer, so formed, or dished or hollowed out, that when forced against the packing ring it will cause it to press inwardly against the pipe, is interposed between the nut and the plate. In this manner a perfectly gas-tight joint, capable of withstanding considerable pressure, is formed, the india-rubber or other packing ring or insertion being firmly held in position so that it cannot escape from the pressure that is put upon it. Fig. 166. De La Vergne Pipe Joint. Perspective View. Figs. 166 and 167 illustrate, in perspective and vertical central section, the De La Vergne type of pipe joint. To ensure a tight joint to withstand high pressure the flanges are connected to the pipes both by screw threads and solder, the latter being run into the annular recesses or clearances shown above the threaded portions, the surfaces of which are well tinned. The joint between the flanges is formed by an annular projection upon the one fitting into a corresponding groove formed in the other, which, when the nuts are screwed up upon the bolts for connecting the flanges, is pressed home and bears upon a suitable packing ring inserted into the bottom of the correspond- ing groove or recess, arid thus forms a perfectly gas-tight joint. Similar 262 REFRIGERATION AND COLD STORAGE. screwed and soldered joints are likewise employed wherever it is necessary to use a return bend, elbow, tee, cross, or other connecting piece. The fittings are either made of malleable iron or steel. The result of covering the thread of the pipe with solder, and running the latter into the above-mentioned annular recess or clearance, and thus forming a compound screwed and soldered joint, is, that what is otherwise the weakest part of a length of piping becomes Fig. 167. De La Vergne Pipe Joint. Vertical Central Section. the strongest. It is stated by the company that it has been invariably found that when the usually applied test of 1,000 Ibs. hydrostatic pressure to the square inch is overrun, the pipe rips open before the joint gives out. Fig. 168 is a vertical central section illustrating the Kilbourn joint, which is especially intended for use where it is necessary to set tubes or pipes in places where an expander cannot be used, or where sweating or soldering is requisite to make a perfect gas-tight joint adapted to PIPES AND JOINTS. 263 withstand very high pressures. As will be seen from the illustration the extremity of the pipe is flanged and secured in a recess in the plate by means of a nut or collar, after which solder is run round it. Where the plate is of insufficient thickness to allow for a depression being left for the solder a rib is formed thereon, as shown. In this manner the inventor claims that the pipe or tube can be so secured to a tube plate or its equivalent that it will be perfectly firm and rigid, and that the solder will retain its hold against all ordinary or usual contingencies, whilst at the same time forming a perfectly gas-tight joint. In Fig. 169 is shown the Kilbourn coupling for connecting together different lengths of pipe, or forming joints between the latter and their connections, where fluid-tight joints to withstand very high pressures are demanded. The usual internally screw-threaded socket Fig. 168. Kilbourn Joint for connecting Pipes to Plates. Vertical Central Section. is chamfered or bevelled at its extremities, and caps having internally chamfered shoulders and bored to fit over the pipes, arid over the socket, are forced against the latter by means of back-nuts, so as to compress the packing rings or jointing materials, placed between the chamfers on the socket and caps, as shown, and thus form a perfectly gas or fluid tight joint. In forming a screwed and soldered joint (Figs. 166 and 167) of the type above described, owing to the comparatively small amount of surfaces in actual contact and tending to prevent leakage, it is essential that great care should be taken in order to ensure the lasting qualities of the joint, and if these precautions be observed, and the joint be well made, it will remain gas-tight for a considerable number of years. Those portions of both the exterior and interior surfaces of the pipes between which the solder is poured should be 264 REFRIGERATION AND COLD STORAGE. first carefully tinned, this operation being performed just before the formation of the joint, so as to avoid the injury that might otherwise occur to the thin layers of tin, and thus to ensure as perfect surfaces as possible and admit of as firm as practicable an adherence of solder to both of the surfaces to be united. All grease having been first care- fully removed by scraping and washing over with killed or prepared hydro- chloric or muriatic acid, the tinning of the faces can be easily performed by means of a soldering iron in the ordi- nary manner. The killing of the hydro- chloric acid is effected by placing in it pieces of zinc until all ebullition ceases, and after cooling, diluting the acid with water in the proportion of two parts of the latter to one part of the former. It will, of course, be understood that to disconnect a screwed and soldered joint, a sufficient application of heat must be made to melt or fuse the solder. Figs. 170 to 183 show a few amongst the numerous other joints that have been brought out and used. Fig. 170 is a very substantial pattern of steel flange union or connection, in which a blue-lead gasket is used which is cast to fit into the square groove in the face of one of the flanges, the rib or projection on the opposite flange also fitting into this groove so that when the flanges are drawn together by the four bolts, the lead gasket will be pressed firmly into the groove, the latter preserving the form and thickness of the gasket, and so forming a perfectly gas-tight joint. Similar types of unions are also shown in Figs. 171, 172, and 173. The flange union shown in Fig. 174 is intended for a joint made with rubber and gasket, or any sheet packing similar to that used for gas, water, and steam, and the flanges are made of steel. By reason of the larger surfaces that are in contact, flange joints Fig. 169. Kilbourn Joint for connecting different lengths of Pipes. Vertical Central Section through Joint. PIPES AND JOINTS. 265 formed in the ordinary manner would remain gas-tight for a longer time than would be the case with screwed joints. Ammonia-tight flange joints can he made by the insertion of a common gasket, and with flanges adapted for the use of sheet packing of the kinds used Fig. 170. Flange Coupling or Union for Lead Gasket. Vertical Central Section. for steam and hydraulic joints, but in the latter case it is preferable to employ flanges having on one of their faces a circular raised rib or fillet A, and in the other face a corresponding groove or recess, as shown in Fig. 174. Figs. 171 and 172. Frick Coupling or Union for Large Pipes. Vertical Central Section and End View. Fig. 175 shows a De La Vergne soldered pipe joint-socket bend or elbow for ammonia pipes. Fig. 176 is a return socket bend. Fig. 177 is a flange bend or elbow for gasket joint. Figs. 178 and 179 is a side view, partly in elevation, and an end view of the Frick evaporating 266 REFRIGERATION AND COLD STORAGE. Fig. 173. Frick Coupling or Union for Small Pipes. Verti- cal Central Section. Fig. 174. Flange Coupling or Union for Sheet Packing. Eleva- tion partly in Central Section. SOLDER Fig. 175. De La Vergrie Soldered Pipe Joint, Bend, or Elbow. Vertical Central Section. Fig. 176. Return Socket Bend. Vertical Central Section. Fig. 177. Flange Bend or Elbow. Vertical Central Section. PIPES AND JOINTS. 267 coil bend. Fig. 180 is an end view, and Fig. 181 is a side view of a flange^return bend, and Figs. 182 and 183 show, in side elevation and vertical central section, a form of return bend or head formed in Figs. 178 and 179. Frick Evaporating Coil Bend. Side View partly in Section and End View. halves for use in places where it is desired to disconnect any one of the coils of a stack. The pipes are, it will be seen, connected to the head by screwed and soldered joints, and the two halves of the head Figs. 180 and 181. Flange Return Bend. End View and Side View. are arranged to form an ordinary flange union, a suitable insertion being used to form a gas-tight joint, and two long side bolts (one of which only is shown fully in the illustrations) and a shorter bolt at the 268 REFRIGERATION AND COLD STORAGE. bend serving to clamp them together. The illustrations are for the most part sufficiently clear, and require but little explanation. o Fig. 182. Return Bend formed in halves. Side Elevation. TLU Fig. 183. Return Bend formed in halves. Vertical Central Section. By the use of electric welding makers are now enabled to provide long continuous coils of pipe and so for the most part dispense with the use of joints in awkward places. MEANS FOR INCREASING COOLING SURFACES OF PIPES. Fig. 184 is a perspective view of a disc or gill which is formed in halves, one of which is shown removed in Fig. 185. The two halves Figs. 184 and 185. Discs or Gills for Increasing the Surface of Refrigerating Pipes. View showing Gill fixed in position on Pipe, and View showing one-half of Gill removed. PIPES AND JOINTS. 269 or parts of the disc are adapted to be secured together upon the pipe by means of iron clips which press them against the pipe. These discs are fixed at regular intervals upon the cooling or re- frigerating pipes in the cold stores or chambers, after they are all put up, and, according to the inventors, their effect is to increase the cooling surface to such an extent that only one foot of pipe is found requisite where four would be necessary without them. These remov- able discs or gills are made by Messrs De La Yergne & Co. Mr B. Lebrun, of Nimy, Belgium, also makes a pattern of cooling pipe with gills or flanges. These pipes are of cast iron, and the gills or flanges are formed therewith. The Maquet gilled piping is made by Mr H. R. Witting, of 9 Southampton Street, London. Several other arrangements on the same principle have been devised for increasing the surface of cooling or refrigerating pipes. CHAPTER XII REFRIGERATION AND COLD STORAGE Refrigeration by means of the Cold- Air Machine Refrigeration by means of Com- pression or Absorption Machines The Brine Circulation System The Direct Expansion System The Cold-Air Blast System Piping for Cold Stores. THE knowledge of the conservative action of cold upon organic sub- stances is probably as old as the existence of human beings, and has been constantly utilised to preserve from putrefaction various alimen- tary substances. Attempts have for many years been made to produce a refrigerated atmosphere by means of ice, but the results obtained are far from satis- factory, the atmosphere of the stores or chambers so cooled being as a rule saturated with moisture from the melting ice, and the meat preserved therein assuming a more or less musty and disagreeable flavour. The possibility, however, of successfully keeping meat in artificially cooled stores or chambers dates only from the invention of Charles Tellier's machine and brine circulating system in 1873, by which he was enabled to create a cold dry atmosphere, wherein organic substances could be maintained constantly at that temperature which is found to be preservative. Mechanical refrigeration is therefore, it will be seen, an art of comparatively modern origin. For the preservation of meat, machines working upon the com- pression system, the absorption system, and cold-air machines are employed. In freezing carcasses for transportation, the cold is best applied gradually at first, so as to ensure an even freezing throughout, and prevent damage to the inner portions of the meat by the freezing of the external surfaces thereof before the internal heat is sufficiently lowered. When frozen or congealed a temperature of at least as low as 18 Fahr. should be maintained. For cooling ships' holds, cold stores or chambers, and other similar purposes, temperatures varying from 15 to 55 Fahr. are required, in accordance with the material 270 REFRIGERATION BY COLD-AIR MACHINES. 271 being dealt with, an even temperature in every part being absolutely necessary. When freezing carcasses they must be hung at such dis- tance apart as to admit of a ready circulation of the cold air round them taking place ; for storage for transportation, however, it is recom- mended to pack them as tightly together as possible, provided no injury through bruising be caused, and that a sufficient clearance or free space be left for the circulation of the cold air between the carcasses and the inner lining of the storage chamber. The tempera- ture of cold land stores or chambers for storing and preserving unfrozen meat need not be lower than 25 Fahr., but should not rise above 30 Fahr. When the meat is frozen, however, as it must be when it has to be kept for any length of time, it may advantageously be maintained at as low a temperature as 15 Fahr. The atmosphere of cold stores in some instances should be kept as dry as practicable ; whilst in others a certain amount of moisture is desirable, as, for instance, when used for preserving fish, eggs, and cheese, which are injured by the air being too dry. For preserving meat for comparatively short periods the best temperature is from 30 to 40 Fahr., as most descriptions are injured to a greater or less extent if permitted to freeze, by the bursting of the vesicles of which flesh is composed. When, however, it is required to be pre- served for a longer period than, say, three weeks it is absolutely essential that the meat should be frozen, otherwise a slight decom- position will take place, and it will become greatly deteriorated. When a cold-air machine is employed for refrigeration, the cold air is, as a rule, admitted to the freezing room, cold storage chamber, or chill room through ducts placed near the ceiling, and after it ha? done its duty is conducted back again to the compressor, wherein, after being mixed with a sufficient amount of fresh air, it is again compressed. The most advantageous method of conveying the cold air from the machine to the chill room or cold store or chamber is by means of wooden trunks or conduits discharging into the latter through an inlet situated at or near the ceiling at one extremity thereof, the used or spent air being withdrawn through a similarly situated outlet and con- duit at the other extremity. All abrupt rises or falls or bends in the air trunks should be avoided, and their length should not be excessive, as the loss experienced through the rise in temperature of the air in the latter case would be very considerable. The extreme limit of distance to which it is advisable to convey the cold air through these conduits is 200 feet. 272 REFRIGERATION AND COLD STORAGE. When carcasses are to be congealed, the temperature of the freezing chamber or room should be maintained at about 10 Fahr. ; as has been already stated, however, the cold should on no account be applied too rapidly at starting, but gradually, so that the internal heat may be first sufficiently reduced, to avoid injury to that portion of the meat, before the outer surface becomes frozen. For after preservation of frozen meat it is sufficient to keep the atmosphere of the chamber or store down to a temperature of about 15 or 18 Fahr. ; it should not, however, be allowed to rise above 20 Fahr. REFRIGERATION BY MEANS OF COLD-AIR MACHINES. According to Colonel B. H. Martindale, C.B., R.E., the general manager of the London and St Katherine Dock Co., in 1886 they had fifty-six refrigerating chambers in two vaults, the smallest of which chambers had a cubic content of 2,273 ft., and the largest thereof of 9,280 ft., the total content of the fifty-six chambers being something over 183,000 cub. ft. The carcasses of the sheep averaged in weight 56, 60, and 72 Ibs. each; and the whole of the chambers completely filled would contain about 59,000 sheep of the first weight, 56,000 of the second, and 44,000 of the third ; in practice, however, a space or clearance had to be left for gangways, and for separating different marks, for which a deduction had to be made from the total storage capacity, and taking the shipments as they chanced to arrive, the above space was equal to the storing of the carcasses of about 44,000 sheep. The cold-air machines employed in connection with the fifty-six chambers in question comprised four Haslam 60,000 cub. ft. machines, and three Hall 30,000 cub. ft. machines, supplied with steam from three multitubular boilers of the marine type, and four boilers of the locomotive type, the former having been found in practice to be the best. One of the Haslam 60,000 cub. ft. machines worked on fifteen chambers, having a total capacity of 48,000 cub. ft., and capable of storing 11,000 carcasses of sheep averaging in weight 72 Ibs. each, but which storage capacity was reduced by gangways, &c., to between 8,000 and 9,000. The engine was kept running twenty hours out of every twenty-four, the stoppage including the time required for clearing the snow from the valves, snow boxes, and air-trunks. The average speed was eighty revolutions per minute, at an air pressure of 44 Ibs. per square inch, giving a temperature of - 70 in the snow REFRIGERATION BY COLD-AIR MACHINES. 273 boxes, and keeping the temperature of the chambers down to from 15 to 18 Fahr., which was found in practice to be about the best temperature to keep the meat at. Better results were obtained in proportion to the fuel consumed, by working at an air pressure of about 44 Ibs. per square inch, instead of 50 Ibs. and upwards ; not giving such a low temperature in the snow boxes, but about - 50 Fahr. instead of - 60 or - 70, and delivering a larger volume of cold air into the chambers. The proportionate rise in temperature was then much less between the delivery from the expansion cylinder and the distant chambers. Twenty-four chambers, with a capacity of 90,000 cub. ft., were worked by two Haslam 60,000 cub. ft. machines, running at an average of seventy revolutions per minute, with an air pressure of 40 Ibs. per square inch, the temperature in the snow box being - 55 Fahr. The atmosphere of the chamber next the machine could, as a rule, be kept at a sufficiently low temperature with but little opening of the delivery ports in the air-trunks, and almost without admitting air at all, as the mere passage of the air-trunks through it kept it nearly cool enough. The greatest care was taken in regulating the delivery and return air-ports or apertures, gradually increasing the area of both in proportion to the increased distance from the machine; the greatest distance to which the cold air was conveyed being 180 ft. The practical result of the observations taken, which extended over some time, was that the rise of temperature in travelling was 1 Fahr. for every 18 or 20 ft. travelled; but this, of course, must not be taken for more than the result arrived at from general working under existing conditions. It was likewise found that from 1 to 1 cub. ft. of cold air per hour would keep cool say at 18 Fahr. 1 cub. ft. of storage at a distance not exceeding 180 ft., or, say, at an average distance of 90 ft. from the machine. The first amount named, viz., 1 cub. ft. of cold air per hour to each cubic foot of storage, was the result arrived at during temperate weather, and this, it is estimated, would most probably be amply sufficient were the chambers fully stored with carcasses, and left entirely undisturbed; but as this is not possible in practice, an allowance has to be made for the opening of doors for the purpose of deliveries and so on; and the second amount, or 1 J cub. ft. of air per hour for every cubic foot of storage that it was desired to keep down to, say, 18 Fahr., was found to be about correct for general practice. The coal consumption was stated to be for three machines, giving out nominally 120,000 cub. ft. of air (one 60,000 cub. ft. and two 18 274 REFRIGERATION AND COLD STORAGE. 30,000 cub. ft. machines), 4J tons of coal in twenty hours; and two 60,000 cub. ft. machines, working under practically similar con- ditions, had a like consumption. The coal used was ordinary Welsh coal, costing about 16s. 6d. per ton. The London and India Docks Co., when the extensions now in progress are completed, will have refrigerated accommodation capable of receiving 550,000 sheep. The extension consists of twelve cold chambers on three floors. REFRIGERATION BY MEANS OF COMPRESSION OR ABSORPTION MACHINES. When refrigerating machines wherein the cooling is effected by the evaporation of a volatile liquid are employed, the refrigeration can be conveniently effected in three ways, viz. : First, by cooling a non-congealable salt brine, and then pumping it through a system of pipes, or of open troughs in the chambers. Secondly, by causing a current of air, generated by means of a fan or otherwise, to impinge against surfaces reduced to a low tempera- ture by the expansion of the refrigerating agent itself, or by an internal circulation of cooled brine, and conducting the cold air to the refri gerating chambers. And thirdly, by expanding the gas direct through pipes placed in the chambers. The main advantage claimed for the first of these plans is that it admits of the machine being stopped, and when an independent brine pump is employed, the brine, wherein a large reserve of cold is stored up, can be continued in circulation for a considerable time before any thawing from rise of temperature and consequently dripping will take place from the pipes. THE BRINE CIRCULATION SYSTEM. The agent employed in the brine circulating system consists of a solution of chloride of sodium or common salt* or of chloride of calcium,* chloride of magnesium, or any other suitable solution capable of standing very low temperatures without congealing. To extract or absorb the heat from the brine, the simplest and best method is undoubtedly that most commonly employed, which consists in passing it through a tank of ample dimensions fitted with suitable coils of pipes, through which the chilled liquefied ether, carbonic acid, ammonia, or other volatile refrigerating agent, circulates, vaporises or gasifies, ex- * For proportions, &c. , of these solutions, see p. 532. THE DIRECT EXPANSION SYSTEM. 275 pands, and subsequently returns therefrom in the form of a gas or vapour to the compressor, in one system ; and in the other, in the form of a strong solution to the generator. An expansion valve or cock, such as one of those illustrated in Figs. 140 to 149 (pages 246 to 252), is fitted to the inlet ends of the submerged coils. The brine, being thus deprived of a large portion of its heat, is then drawn away from this refrigerating or cooling tank or vessel by the brine circulating pump, and is forced through the system of cooling pipes in the refrigerating chamber or cold store. The arrangement of the cooling pipes in cold stores for preserving provisions of a perishable nature requiring to be kept at various tem- peratures between 25 and 45 Fahr., in accordance with the descrip- tion and nature of the provisions, or of those in chambers for freezing or congealing meat and keeping it frozen, which require to be main- tained at temperatures of between 10 and 18 Fahr., according to the work demanded, only differ from other installations in the par- ticular disposition and numbers of the pipes, the chambers intended for the latter purpose being, of course, fitted with the greatest number. THE DIRECT EXPANSION SYSTEM. When the direct expansion system is in use the pipes should invariably be of wrought iron, and even where the brine circulating system is employed they should preferably also be of the latter material in the case of freezing chambers, as the heat from the chambers passes more readily through the thinner walls of the smaller wrought- iron pipes. Besides which there is, as has been already mentioned elsewhere, a considerable saving of space. One advantage of this system is that a more economical and rapid cooling is effected than with the brine circulation ; another is the simpli- fication of the apparatus and the reduction in the first cost thereof. To counterbalance which advantages, however, there is the danger to human life, of damage to the contents of the refrigerating chambers, and of fire, should any leakage of the gas or vapour from the cooling pipes take place, and also the impossibility of shutting down the machine even for a few minutes without the cooling pipes commencing to drip. As regards damage to the contents of the rooms or chambers by reason of an escape of the refrigerating agent, however, carbonic acid is known to be non-injurious, and as regards ammonia the fears of any deterioration in the quality of fresh meat which is being frozen or preserved, resulting from any accidental leakage of the pipes, would 276 REFRIGERATION AND COLD STORAGE. seem to be totally groundless, judging from the results of recent practice, and the opinion of experts. On this head the following extract from an article published in the Scientific American in 1889 is of interest : "Some years ago I)r B. W. Richardson, in a communication to the Medical Society, called attention to the antiputrescent properties of ammonia, and showed that blood, milk, and other alterable liquids could be preserved for a long time by adding to them certain quantities of solution of ammonia ; and solid substances, such as flesh, by keeping them in closed vessels filled with ammonia gas. Some doubts that would appear to have been raised as to the results reported, on the ground that ammonia was itself a product of decomposition, induced Dr Gottbrecht, of the University of Greifswald, to repeat the experi- ments with the result of practically confirming all Dr Richardson's statements. After some preliminary experiments, in which animal matter placed in 5 per cent, of ammonia solution was found free from putrescence after nearly two years, ammonium carbonate was used in place of the free alkali for the sake of convenience. The first experiment made with the washed intestines of freshly killed pigs showed the power of ammonium carbonate to retard putrefaction to be directly dependent upon the concentration of the solution, a 1 per cent, solution retarding it until the third day, a 10 per cent, solution until about the sixtieth day. When added to gelatine in which putrefaction had already been set up by inoculation, it was found .that a 5 per cent, solution so modified the conditions that the putrescence ceased, and a 2J per cent, solution inhibited the development of bacteria, so that the liquefaction of the gelatine was practically stopped. Other experi- ments showed that in an atmosphere impregnated with ammonium carbonate meat could be kept for six months, and at the end of that time remain nearly unaltered." When chambers are refrigerated on the direct expansion system it is nevertheless essential that the system of pipes employed, which can be arranged on any of the plans adopted in the case of brine circulation, should be such as to reduce as far as practicable to a minimum the chance of leakage taking place at the joints, cocks, valves, &c., as, independently altogether of any possible damage to the contents of the stores or chambers, it is highly desirable, for economical reasons, that as little as possible of the circulating agent be lost. Various gas-tight joints have been already briefly described in a previous chapter. Ammonia, both in a liquid and gaseous condition, has no chemical THE DIRECT EXPANSION SYSTEM. 277 effect whatever upon iron, consequently the cooling pipes require no protection except upon the exterior, which should receive a coat of paint every year to prevent them from rusting. So long, however, as the pipes are coated with snow or ice no corrosion will take place, even externally, as they are thoroughly pro- tected thereby from the oxidising effect of the atmosphere ; when, how- ever, they are subjected to alternate freezing and thawing, as is usually the case during actual work, when the chambers or stores are alternately in and out of use, then they must be protected as above mentioned. 40 35 30 25 SS 51 '+S 39 Fig. 186. Diagram showing the Variation in Capacity, &c., of a Refrigerating Machine. There is not the least doubt but that the direct expansion system is, as has been before mentioned, more economical than the brine circu- lation system. This will be obvious when it is remembered that every transmission of heat must of necessity entail a loss of efficiency. A far higher evaporating pressure can be maintained in direct pipes than in evaporating coils in a brine tank, whilst at the same time they have still within them a far lower temperature than in the latter. The result of this is that, in the compression system, the gas is sucked into the compressor at a greater back pressure when direct expansion is 278 REFRIGERATION AND COLD STORAGE. employed, and a far larger amount of efficiency is obtained. The cold, moreover, being produced exactly where it in required, there is practically no waste. The diagram, Fig. 186, and the following table, show the variations in capacity, &c., of a refrigerating machine, and the economy of direct expansion, as drawn up by the De La Yergne Co. In the above diagram the line marked "capacity of machine" shows the diminished capacity as the back pressure is reduced. Tf the machine has a capacity of 10 tons at a return pressure of 28 Ibs., as shown by the vertical height of the curve, it has a capacity of 5 tons only with a return pressure of 6 Ibs. Under the same circumstances the cost of fuel per ton is increased in the ratio of the vertical heights to the curve marked " cost of fuel," namely, from 14-5 to 25. In other words the cost per ton is nearly doubled while the capacity is halved. The work as seen by the curve marked "work required " diminishes very slowly. CUBIC FEET OF AMMONIA GAS PER MINUTE TO PRODUCE ONE TON OF REFRIGERATION PER DAY. CONDENSER. P 103 H5 127 139 153 168 185 200 218 p t 65 70 75 80 8 S 90 95 100 105 4 -20 5-84 5-9 5-96 6-03 6-06 6-6 6"23 6-30 6-43 QJ 6 -15 5-35 5-4 5-46 5-52 5-58 5-64 5-70 5-77 5-83 1 9 -10 4-66 4-73 4-76 4-81 4-86 4-91 4-97 5-05 5-08 H 13 - 5 4-09 4-12 4-17 4-21 4-25 4-30 4-35 4-40 4-44 M 16 3-59 3-63 3-66 3-70 3-74 3-78 3-83 3-87 3-91 1 20 5 3-20 3-24 3-27 3-30 3-34 3-38 3-41 3-45 3-49 24 10 2-87 2-9 2-93 2-96 2-99 3-02 3-06 3-09 3-12 28 15 2-59 2-61 2-65 2-68 2-71 2-73 2-76 2-80 2-82 33 20 2-31 2-34 2-36 2-38 2-41 2-44 2-46 2-49 2-51 39 25 2-06 2-08 2-10 2-12 2-15 2-17 2-20 2-22 2-24 45 30 1-85 1-87 1-89 1-91 1-93 1-95 1-97 2-00 2-01 51 35 1-70 1-72 1-74 1-76 1-77 1-79 1-81 1-83 1-85 This shows very plainly the economy of direct expansion. The ammonia in the coils of the brine tank must be cooled below the brine or the directly expanded ammonia. If the difference be 10, say 5 COLD-AIR BLAST SYSTEM. 279 instead of 15, then the capacity of the machine is reduced in the ratio of 10 to 8 or 20 per cent., and the cost for fuel increased in the ratio of from 14-5 to 17 '5 or 20 per cent. These are physical facts which cannot be explained away, and the economy of direct expansion in practice over both brine and air circulation is usually greater than the diagram and table illustrates. In the brine system, on the other hand, the large refrigerating or cooling tank is exposed to the atmosphere, and even when insulated as perfectly as possible, a considerable amount of heat is unavoidably absorbed, which is, of course, a total loss; considerable fuel con- sumption is moreover required in the brine circulation system, for the power consumed in pumping the large quantities of brine through the system of pipes in the refrigerating chambers or cold stores, which pipes sometimes run to many thousands of feet in length, and thus give rise to a large amount of friction ; and besides, after being in use for some time, they may become internally coated with rust, and with a slimy deposit, which not only produces a considerable increase in the amount of the friction to be overcome in driving the brine through them, but furthermore forms a sort of non-conducting coating, and lessens, to an appreciable extent, the heat-absorbing qualities of the system. Altogether it is not improbable that the entire loss through the additional consumption of fuel entailed from all the above causes does not, in many instances, fall far below 25 per cent, of the entire amount. CoLD-Am BLAST SYSTEM. Apparatus is also in use which is so arranged that the refrigerating coils or pipes are placed in a separate compartment connected with the refrigerating chambers or cold stores, and air, having been cooled in the first, is passed into the latter, the circulation being kept up by means of a fan or blower. The refrigerated air is sometimes first washed and freed from snow by passing it through a shower of cold brine, and dried by exposing it to the absorbent action of calcium chloride or other hygroscopic material. This arrangement is possessed of one of the advantages derived from the use of cold-air machines, viz., that every part of the apparatus is situated externally to the refrigerating chamber or cold store, and consequently accessible at all times. Dripping from the refrigerating pipes when the machine is stopped for a short time, and the temperature of the chamber or store rises slightly, is also avoided. 280 REFRIGERATION AND COLD STORAGE. On the other hand, however, there is a considerable loss by reason of the absorption of heat by the cold air on its way from one chamber to the other ; an increased consumption of fuel, owing to the power required to work the fan or blower for keeping up the air circulation ; and finally the loss of possibly valuable space taken up by the chamber required for the purpose of cooling the air. The plan wherein air, refrigerated by contact with brine-cooled surfaces, instead of by direct expansion, is passed into the chambers or stores, is evidently still more costly inasmuch as there are not only the losses entailed from the above-mentioned sources, but, furthermore, that caused by another transmission of heat. PIPING FOR COLD STORES. AMOUNT OF REFRIGERATION REQUIRED. The refrigeration required will be governed by the size of the store, the amount of and frequency with which the goods are brought into the store and removed from it, the temperature of the goods, and their specific heat, the mean external temperature, the greater or lesser perfection of the insulation, and various other matters, which render it totally impossible to lay down any hard and fast rules. A very usual practice is to provide 1 ft. run of 2-in. pipe for every 7 cub. ft. of space contained in the store, but sometimes the proportion used is as much as one to five, whilst again it is occa- sionally reduced to one to twelve. For refrigerating meat, in which case it is not desirable to cool the exterior too rapidly before the interior has had time to cool to a certain extent, the best proportion to employ is one to ten. AMOUNT OF REFRIGERATING PIPES NECESSARY FOR CHILLING, STORAGE, AND FREEZING CHAMBERS. Chilling-Rooms or Chambers, refrigerated on the direct expansion system, 1-ft. run of 2-in. piping for each 14 cub. ft. of space; on the brine-circulation system, 1 ft. run of 2-in. piping for each 8 cub. ft. of space. Freezing Rooms or Chambers, refrigerated on the direct expansion system, 1-ft. run of 2-in. piping for each 8 cub. ft. of space ; on the brine-circulation system, 1-ft. run for each 3 cub. ft. of space. Storage Rooms or Chambers, refrigerated on the direct expansion PIPING FOR COLD STORES. 281 system, 1-ft. run of 2-in. piping for each 45 cub. ft. of space; on the brine-circulation system, 1-ft. run of 2-in. piping for each 15 cub. ft. of space. EXTREME LIMITS OP CUBIC FEET OF SPACE PER RUNNING FOOT OF 2-iN. PIPING. These are given in the following table : Breweries. Medium insulation Chip and stock rooms ... ... ... ... 1 to 22 Fermenting and settling rooms ... ... ... 1 ,, 22 Packing-rooms ... ... ... ... 1 ,, 18 Hop-rooms ... ... ... ... ... 1 ,, 25 Packing House Chill-rooms for beef ... ... ... ... 1 ,, 12 Hogs... ... ... ... ... ... 1 ,, 10 Freezing-rooms ... ... ... ... 1 ,, 6 or 7 Cold Storage Cold storage rooms ... ... ... ... 1 ,, 25 or 30 Cold storage house and freezing-rooms ... ... 1 ,, 8 For eggs, brine preferred ... ... ... 1 ,, 12 Cold storage ... ... ... ... ... 1 25 Ice storage ... ... ... ... ... 1 ,,20 Fish freezing (direct expansion) ... ... ... 1 ,, 2 CUBIC FEET OF SPACE PER RUNNING FOOT OF 2-iN. PIPE DIRECT EXPANSION.* Fermenting and settling rooms Packing-rooms ... Hop-rooms For packing house in chill-rooms for beef ... The same room for hogs ... The freezing-rooms Cold storage rooms Under cold storage houses the freezing-rooms Cold storage for eggs General cold storage Ice storage Fish freezing, about to 20 ,,18 ,,25 12 ,,10 6 or 7 ,, 25 30 8 ,,12 25 ,,20 . 2 The following five tables are given by Professor Siebel in the " Compend of Mechanical Refrigeration." * Otto Luhr, American Brewers' Review. 282 REFRIGERATION AND COLD STORAGE. LINEAL FEET OF I-IN. PIPING REQUIRED PER CUBIC FOOT OF COLD STORAGE SPACE. Size of TEMPERATURE, DEGREES FAHR. Building in T 1 Cubic Feet, Insulation, more or less. 10 20 30 40 50 100 Excellent 3-0 1-78 0-48 0-36 0-24 0-15 Poor 6-0 1-50 0-90 0-66 0-48 0-30 1,000 Excellent 1-0 0-26 0-16 0-12 0-08 0-05 Poor 2-0 0-50 0-30 0-22 0-16 o-io 10,000 Excellent 0-61 0-16 o-io 0-075 0-055 0-035 Poor 1-2 0-33 0-20 1-15 0-11 0-07 30,000 Excellent 0-5 0-13 0-08 0-06 0-040 0-025 Poor 1-0 0-25 0-15 0-11 0-03 0-05 100,000 Excellent 0-38 o-io 0-06 0-045 0-03 0-009 Poor 0-75 0-20 0-12 0-09 0-06 0-018 NOTE. The above quantities of pipe refer to direct expansion, and should be made one and one-half times to twice the length for brine circulation. To find the corresponding lengths of l-in. pipe divide by T25 or multiply by 0'8 ; of 2-in. pipe divide by 1'08 or multiply by 0*55. NUMBER OF CUBIC FEET COVERED BY 1 FT. OF I-IN. IRON PIPE. Size of TEMPERATURE, DEGREES FAHR. Building in Cubic Feet Insulation. more or less. 10 20 30 40 50 100 Excellent 0-3 1-3 2-1 2-8 4-2 7-0 Poor 0-15 0-7 1-1 1-5 2-1 3-5 1,000 Excellent 1-0 4-0 6-0 8-4 12-4 20-0 Poor 0-5 2-0 3-2 4-5 6-2 10-0 10,000 Excellent 1-7 6-0 10-0 13-0 18-0 28-0 Poor 0-85 3-0 5-0 6-5 9-0 14-0 30,000 Excellent 2-0 8-0 14-0 18-0 25-0 40-0 Poor 1-0 4-0 7-0 9-0 13-0 20-0 100,000 Excellent 2-6 10-0 17-0 22-0 33-0 110-0 Poor 1-3 5-0 8-5 11-0 17-0 55-0 i NOTE. The above figures refer to direct expansion : from one-half to two-thirds of the spaces only would be covered by the same amount of pipe in case of brine circulation. To find the corresponding amounts of cubic feet of space which would be covered by one lineal foot of l|-in. pipe, multiply by 1*25 or divide by 0'8 ; of 2-in. pipe, multiply by 1'08 or divid by 0'55. PIPING FOR COLD STORES. 283 NUMBER OF CUBIC FEET COVERED BY I-TON REFRIGERATING CAPACITY FOR TWENTY-FOUR HOURS. Size of TEMPERATURE, DEGREES FAHR. Building in T Cubic Feet Insulation. more or less. 10 20 30 40 50 100 Excellent - 150 600 800 1,000 1,600 3,000 Poor - 70 300 400 600 900 2,000 1,000 Excellent - 500 2,500 3,000 4,000 6,000 12,000 Poor - 250 1,500 1,800 2,500 5,000 10,000 10,000 Excellent - 700 3,000 4,000 6,000 9,000 18,000 1 Poor - 300 1,800 2,500 3,500 7,000 14,000 30,000 Excellent - 1,000 5,000 6,000 8,000 13,000 25,000 Poor - 500 3,000 3,500 5,000 11,000 20,000 100,000 Excellent - 1,500 7,500 9,000 14,000 20,000 40,000 Poor - 800 4,500 5,000 8,000 16,000 35,000 REFRIGERATING CAPACITY IN B.T.U. REQUIRED PER CUBIC FOOT OF STORAGE ROOM IN TWENTY-FOUR HOURS. Size of TEMPERATURE, DEGREES FAHR. Building in Cubic Feet, Insulation. more or less. 10' 20 30' 40 50 100 Excellent 1,800 480 360 284 180 95 Poor 4,000 960 480 470 330 140 1,000 Excellent 550 110 95 70 47 24 Poor 1,100 190 165 110 55 28 10,000 Excellent 400 95 70 47 30 16 Poor 900 160 110 81 40 20 30,000 Excellent 280 55 47 35 22 11 Poor 550 95 81 55 26 14 100,000 Excellent 190 38 30 20 14 7 Poor - - - 350 63 55 35 18 4 284 REFRIGERATION AND COLD STORAGE. ! ' of co" CD" ocT oT cT cT r-T c^T of co" ocT r-4" i-T of of o" IT"- oT oT of of cT o" i-* o~ oo" cT co" rjT co"i> t-r CCW5l>OSO(NeoeC F-T r-n" C^ " " f- CO - o Ot o 1 . 5 >fa ta !^ 2 I ) o* * cc" *" co" t^ 1 oT o" co" cT orT of o" cT ^ .SP 5 P3 fl b 5 fl * 1^ 11 g>g 5^ J8> 1 '00 s comes condensed, either in the form of water or of hoar frost. In the latter case dripping is liable to commence on any rise of temperature COLD ROOMS OR CHAMBERS. 301 in the room or chamber by reason of the shutting down of the machine or from other cause. This dripping is, as has been already mentioned, more especially liable to occur in cases where the direct expansion system of cooling is in use. 302 REFRIGERATION AND COLD STORAGE. DO D D D JOO 10 000000 000 U D 000000 o o D D Figs. 199, 200, and 201. Refrigerating Installation on the Humboldt System, erected at Abattoir, Riga. Transverse Sections. COLD ROOMS OR CHAMBERS. 303 Fig. 196 is a sectional view showing the arrangement of a cold store with beef chill-rooms cooled or refrigerated by means of a Haslam patent brine air-cooling battery. The open trough system has been already alluded to, and it is one of great simplicity, and is frequently used for the hog-cooling rooms in bacon factories. Two, three, or other suitable number of troughs are usually placed in line, vertically, one above the other, over each hook or hanging rail, and the flow of brine can be regulated by any well- known and convenient means. A large surface of cold brine is in this system advantageously exposed for absorbing heat ; on the other hand, however, the open troughs have the disadvantage of taking up a very considerable amount of valuable space. Figs. 197 to 201 show a meat cooling plant on the Humboldt system erected by them at the municipal abattoir, Riga, Russia. This plant is arranged with dry-air coolers for direct evaporation, the type of cooler employed being the Fixary improved by Humboldt in accord- ance with the dictation of their experience in the requirements of plants for this purpose. The cooling pipes are arranged in the chilling, cooling, and curing rooms of bacon factories in a number of other different ways, the system having frequently to be specially adapted to the existing buildings. Sometimes the pipes are placed in the form of coils in a separate chamber or loft provided in the ceiling of the main room or chamber (as shown in Fig. 202, which shows an installation on the direct expansion system), and air, admitted through suitable apertures from the room beneath, or by means of ventilators, and cooled by pas- sing over the surface of these coils, is allowed to circulate by gravity, or is rapidly circulated by means of fans through the room below. A somewhat similar arrangement of brine or cooling pipes is also often em- ployed in beef and other meat rooms. An advantage of this plan is that it effectually prevents any dripping and moisture in the chill-room. In an arrangement designed by Mr Puplett, the refrigerating pipes or coils and circulating fan are fixed in a separate compartment quite distinct from the cold rooms, but connected therewith by trunks or ducts. The cooling is effected by the constant circulation through the chill or meat rooms of a current of air that has first been cooled by passing it over the refrigerator. The air is washed and purified by being passed through a series of sprays of cold brine, and then over the refrigerator, by which it is dried and reduced to any desired temperature. The fan draws the air from the rooms through the suction trunk, and returns it by the delivery trunk after it has passed 304 REFRIGERATION AND COLD STORAGE. through the refrigerating chamber and been washed, cooled, and dried ; the air thus becomes colder, and is purified each time it passes over the refrigerator. o 60 Another method of arranging the cooling pipes is to provide coils on the sides of the chill-room, or where the chamber is of considerable dimensions, in rows placed vertically at suitable intervals lengthways of COLD ROOMS OR CHAMBERS. 305 the latter, the carcasses being suspended by hooks in the usual manner from meat or hanging rails, situated overhead, between the coils. When the refrigerating pipes are placed directly in the cold store, suitable drip-trays (as shown in Fig. 195) can be provided if required. Refrigerating machines are likewise very advantageously employed in bacon-curing factories or works, for enabling mildly-cured bacon to be produced in summer, by artificially reducing the temperature of the chill-rooms and curing-cellars. A usual arrangement is shown in Fig. 203, which comprises rows ^*^wSB^x^ Fig. 203. Arrangement of Cooling Pipes in Chill-room and Curing-cellar in Bacon Factory. Transverse Section. of cast-iron flanged pipes which are fixed overhead, preferably sus- pended from the ceiling, over the whole area of the chill-rooms and curing-cellars, and through which system of pipes brine cooled in the usual manner is circulated so as to lower the temperature of the rooms to about 40 Fahr. By means of cocks provided on the different branch mains the speed of the flow of brine through the various circulations, and consequently the temperature of the rooms, can be regulated, and reduced, or increased at pleasure. In factories of moderate size the machine may usually be stopped at night and on Sundays, the cold stored up in the brine in the pipes being enough to 20 306 REFRIGERATION AND COLD STORAGE. keep the temperature of the room sufficiently low ; in very hot weather, and in very large establishments, however, the machine will have to be run continuously night and day. Both the chill or cooling rooms and the curing-cellars are fitted up in practically the same manner ; the work in the chill or cooling rooms where the hot meat is cooled down is much greater in proportion to their size, however, and is moreover intermittent, consequently a proportionately larger number of brine pipes are placed therein, and the brine is turned on or off as the rooms are full or empty ; on the other hand the work in the curing-cellars is less and regular, and, therefore, a much smaller number of brine pipes are required, the circulation of brine being kept up all the time the machine is running, and a perfectly steady and even temperature maintained. The reason that artificial refrigeration is now imperatively required in bacon-curing works is on account of the demand that has arisen for mild-cured bacon, Formerly' the pigs, after being killed, were cooled simply by exposure to the .atmospheric air, being subsequently cured in underground cellars at the temperature of the earth, or from 52 to 55 Fahr. In order to prevent the rapid decomposition, and con- sequent taint of the bacon which would otherwise inevitably occur at these comparatively high temperatures, the latter was charged with an excessive amount of salt as a preventative. This excessive salting was indispensable in summer especially, when, indeed, curing was almost prevented, although bacon at that season is in the greatest demand, and the highest prices are obtainable. The modern requirement, however, for more and more mild-cured bacon has ^rendered absol- utely necessary an artificial reduction of the temperature of the chill- rooms and curing-cellars. The first attempts in this direction were made by constructing the cellars with iron ceilings, on the tops of which were stored large quantities of ice, a system which is found to be, when properly carried out, sufficiently effective, but is very expensive, not only by reason of the first cost of the iron ceilings and the necessary supports, but also by reason of the space occupied by the ceilings and ice chambers, and furthermore on account of the large outlay entailed for the ice itself, and the labour of handling it. There is, besides this, the risk of the supply of ice running short in the hot weather, with, of course, disastrous results. Fig. 204 is a horizontal section showing a plan of a small cold storage chamber of 1,000 cub. ft. capacity, adapted for the use of butchers, &c. The refrigeration is effected by a Haslam cold-air COLD ROOMS OR CHAMBERS. 307 machine, of 6,000 cub. ft. per hour capacity, arranged to be driven direct by means of a gas engine. A is the gas-engine cylinder, B the air-compression cylinder, and c the expansion cylinder. The air-com- pression cylinder B is arranged horizontally in front of, and in line with, the cylinder A of the gas motor, and the expansion cylinder c is placed vertically, and works a disc secured upon the opposite end of the crankshaft from the fly-wheel. The advantages of a gas motor for driving the small cold-air 308 REFRIGERATION AND COLD STORAGE. machine required for an installation of this description are obvious, and comprise : non-increase of fire insurance premium, and ability to start the machine at any time, without having to wait to get up the necessary steam pressure in a boiler, as must be done in the case of a steam-driven cold-air machine, and, moreover, except where gas is at an abnormally high price, a considerable economy in cost of running. Fig. 205 is a perspective view, the end wall and a portion of the front wall being removed, showing a small cold store or chamber, refrigerated by means of a Puplett patent ammonia compression machine, which chamber is especially designed for butchers, bacon- curers, dairymen, fish and game dealers, &c. Chambers of this Fig. 205. Small Cold (Store for Butchers, &c., Cooled by an Ammonia Compression Machine. description are constructed with an outer and an inner skin, each of which is composed of two layers, of 1-in. tongued and grooved boards, put together perfectly air-tight, and having an intervening space or clearance of about 8 in., filled with charcoal, cork, or other good non- conducting material. The dimensions of the chambers, as usually constructed, vary from a storage capacity for frozen meat of 6 to 50 tons or more, and their daily meat-cooling capacity to 32 Fahr. runs from 20 cwt. up to 200 cwt. or more. In Fig. 206 is shown in vertical section a small cold storage room cooled by a Triumph ammonia compression machine, which would be suitable for an hotel or private residence. A plant of this description COLD ROOMS OR CHAMBERS. 309 can be readily operated by an ordinary man without the help of a skilled attendant, and would only require about an hour's attention during the day. The brine tank shown in the drawing keeps the refri- gerator or cold storage chamber cold during the night. The com- pressor, which is of the double-acting horizontal type, is mounted upon a strong tank forming the condenser, and can be operated by any available source of power. A description of the Triumph compressor will be found in the chapter upon " Ammonia Compression Machines." Fig. 207 depicts the arrangement of a one-ton ice-making and refrigerating plant in an hotel, in which, it will be seen, a number of separate cold storage rooms or chambers for different classes of pro- Fig. 206. Small Cold Storage Room for Hotel or Private Residence. Vertical Section. visions are provided. This installation is cooled by an ammonia com- pression machine made by the A. H. Barber Manufacturing Co., Chicago, which type is also described in the chapter mentioned above. It is usually advisable to provide in the kitchen of an hotel, or adjacent thereto, a short order box, which enables the too frequent opening of the main cold storage room or chamber to be avoided. This box may be cooled by a set of pipes, through which the cold brine, or, when direct expansion is employed, the refrigerating gas or medium, passes on its return to the machine after doing duty in the main cold store or chamber. Arrangements can also be made for cooling carafes, freezing ice creams, and cooling the bar box. 3io REFRIGERATION AND COLD STORAGE. The cold storage room in an hotel does not, of course, differ mate- rially in any respect from any other, but the peculiar requirements of an hotel, and the great difficulty experienced in getting the servants to understand the necessity for judicious and careful management, are frequently very great. To avoid the undue admission of heat to such cold storage rooms or chambers .by careless persons leaving the doors open, and to render it impossible for anyone using the cold storage room to do this under any circumstances, the author has devised the door shown in horizontal section in Fig. 208, and in vertical section in Fig. 209. This door is, it will be seen, of a crescent or semi-cylindrical form, in horizontal sec- Fig. 207. Cold Storage Rooms and Ice-Making Plant in Hotel. Perspective View. tion, and is mounted upon a central axis, so as to be free to turn or rotate easily thereon in a suitable casing having two apertures, the one opening into the cold storage chamber and the other to the exterior, and between the inner surface of which casing and the outer surface of the door an air-tight joint is made by means of strips of india-rubber, felt, or the like, or by spring-actuated rubber or felt- faced strips, &c. To use this door the aperture or opening admitting to the interior of the same is brought opposite to the one or other of the apertures or openings in the casing by revolving the door upon its axis, sunk handles admitting of its ready manipulation. The person desiring COLD ROOMS OR CHAMBERS. COLD ROOM Figs. 208 and 209. Rotating Air-Lock Door for Cold Storage Rooms in Hotels, &c. Sectional Elevation and Horizontal Section. 312 REFRIGERATION AND COLD STORAGE. to pass through then steps inside the hollow semi-cylindrical door and rotates it until the aperture or opening thereof coincides with the other or second aperture in the casing, when he can pass out through the latter. Shelves in the interior of the door admit of a number of dishes being placed thereon and moved into the cold storage chamber at one operation, or of being turned so as to communicate with the cold storage chamber, and brought back again when required. It will be seen that it is impossible to turn this door so as to open a through communication between the interior of the room and the exterior, and the interchange of air at each opening of the door is consequently limited to the cubical contents of the hollow or semi- cylindrical door itself. VENTILATION OP COLD STORAGE CHAMBERS. The ventilation of cold storage rooms can be effected in a number of different ways, but as a general rule no provision whatever of a special nature is made for the removal of the vitiated air, it being considered that sufficient change of air is brought about by the opening of doors, &c. In fact, as removing any of the cold air entails the necessity of replacing same by more air at the same low temperature, and thereby necessitates additional refrigeration, there is the same dis- like to ventilation as exists in the case of a warm room where ventila- tion demands the admission of the cold external air, and the expendi- ture of more fuel to heat it. The various expedients resorted to for the ventilation of cold storage rooms comprise, in addition to the opening of doors above alluded to, the occasional opening of windows, where such exist, the provision of ventilating shafts in the ceilings, and, what is perhaps the most efficient, by artificial means, through an exhaust fan connected through suitable pipes fitted with doors or valves with the cold storage room. When ventilating shafts are provided, and there are a number of cold storage rooms contained in the same store, the ducts or pipes may be placed in the corridors, each room being connected thereto through a pipe with a valve or damper so as to enable the amount of ventilation to be properly regulated, and the various ducts or pipes from the corridors having a common termination in the chimney stack, which latter provides a means for efficiently ventilating the rooms at all times. CIRCULATION OF AIR. 313 It must be remembered that in cold storage rooms or chambers the air, being cold, sinks to the bottom, and that the tendency is therefore for it to escape through the crevices about the doors, or when the latter are opened, and thereby create a down-draught so as to render any attempt to ventilate by means of a short shaft without artificial means to produce an air current abortive. Moisture has the property of absorbing gases and impurities, and consequently the moisture in the air of a cold storage room will take up all the emanations from the stored products. It follows, therefore, that if the air be subsequently relieved of its moisture it will be prac- tically purified, as most of these gases can be removed. All atmospheric air contains the germs of fungus or mould, which germs are very rapidly developed under such favourable conditions as the presence of a large amount of moisture in the air, and high tem- peratures, but are destroyed and removed from air in a dry and cold condition. This moisture can only be removed by ensuring a proper circulation of the air of a cold storage room relatively to the articles stored therein and the refrigerating pipes or other cooling surfaces. CIRCULATION OF AIR IN COLD STORAGE CHAMBERS. The circulation of air in cold storage rooms or chambers is a matter of primary importance, and one which in too many cases does not receive the attention which it deserves, with the result, more especially in the case of small rooms or chambers, that the condition of the atmosphere is anything but satisfactory, and great difficulty is experienced in keeping provisions in good condition in them. There are two main systems of air circulation in use, viz., the gravity air circulation and the mechanical or forced air circulation. The following particulars are extracted from three interesting and instructive articles by Mr Madison Cooper, a well-known expert upon refrigerating matters in the United States, and which articles appeared in the American journal Ice and Refrigeration, for May, June, and August 1901. "METHODS OF PIPING THAT HINDER CIRCULATION. " When mechanical refrigeration first came into the field, the arrangement of cooling surfaces and a provision for air circulation was neglected about as it was by the pioneers in natural ice refrigeration. The cooling pipes were placed almost anywhere, regardless of the laws of gravity which control air circulation. At first the ceiling of the room 314 REFRIGERATION AND COLD STORAGE. was a favourite place for locating the coils of pipes for cooling the room. The ceiling was utilised because thus the pipes were out of the way in piling up goods, and also on the theory that * cold would naturally drop.' Cold, or, more accurately speaking, cold air, will naturally drop, but placing the pipes on the ceiling of a room will not assist the circulation ; it will, in fact, produce practically no circulation at all if the whole ceiling of the room is covered with pipes uniformly. Ceiling pipes have generally been abandoned for the more rational method of placing the pipes on the side walls of the room. "Fig. 210 shows ceiling piping, and should make plain why no circulation is created when the pipes cover nearly the whole top of Fig. 210. Diagram showing Gravity Air Circulation in Cold Storage Room Chamber, with Ceiling Piping. the room. As is well known, cold air is heavier than warm air and, if free to move, the cold air will seek a lower level than the warm air. This movement of the cold air downward and the warm air upward is what is known as gravity air circulation. A slight difference in the temperature will cause a circulation of air if the warm and cold air are separated from each other and not allowed to mix, which would cause counter-currents and retard the circulation. In a cold storage room the air in contact with the cooling coils, as it is cooled, flows downward towards the floor by reason of its greater specific gravity. The comparatively warm air above is drawn down to the pipes, where it is in turn cooled, and the flow is continuous. If the entire ceiling is covered with pipes, what results? The air in contact with the CIRCULATION OF AIR. 315 pipes cannot fall because it cannot be replaced by warm air from above. The result is that practically no circulation of air takes place in such a room. A slight local circulation in the vicinity of the pipes is all that results, except under unusual or accidental conditions. The goods are cooled for the most part by direct conduction and radiation ; the top tier of goods would be cooled directly from the pipes and each tier under successively from its neighbour above in the same manner. "Goods are cooled by radiation by the passage of heat from the goods directly to some colder object, without the heat being conveyed by the movement of the air, as it should be, and as it is where a good circulation is present in the room. In a room in which the goods are cooled by radiation mostly, the moisture instead of being deposited entirely on the cooling pipes, as it should be, is also likely to be ^ \ \ \ Fig. 211. Diagram showing Gravity Air Circulation in Cold Storage Room or Chamber, with Side Wall Piping. deposited on the walls of the room or on the goods themselves. The result of such a condition would be serious. This cooling by radiation, as compared with cooling by a circulation of air, may seem like a very finely spun theory to some, but let the sceptic watch his house for a demonstration. Is there any practical cold storage man now in the business who has not noticed an accumulation of frost or moisture on goods if they were piled too near to the exposed cooling pipes 1 What causes this result ? Radiation, nothing else. "The bad effects of radiation cannot be altogether overcome by placing the pipes on the sides of the room, but it is counteracted to some extent by the resulting circulation of air. Fig. 211 shows side wall piping and the resulting circulation, which is confined largely to a small space near the coils. The arrows show approximately the path of circulation. If the room is wide, no circulation at all will take place 316 REFRIGERATION AND COLD STORAGE. near the centre. In some cases pipes have been carelessly placed two or three feet down from the ceiling. This results in the air of the room becoming stratified a warm layer of air in the top of the room resting on a cold layer beneath. This may be operative to such an extent as to cause a difference in temperature between floor and ceiling as great as 10 Fahr. A case has come to the writer's notice with O exactly these conditions. Another bad arrangement of side wall piping was that of a room more than 50 ft. square piped completely around on the side walls from floor to ceiling, with the exception of the doors. No circulation^could penetrate to the centre of such a room, and conditions were very poor in consequence. "MEANS FOR IMPROVING AIR CIRCULATION. " The placing of a screen or apron in front of the side wall piping, as illustrated in Fig. 212, marks the first scientific step toward a better- y//'/////////////////////////////////////S/s//s/////s//////s/ss ^ U 5 5 - 120 " At the end of each twenty-four hour period the quarter bricks were taken from the water, the outer surfaces carefully dried by cloth and blotting paper, and then the bricks were immediately weighed before any evaporation could take place from the pores of the brick. This was repeated in most of the tests until the bricks had been immersed for a period of 1 20 hours. After this continued immersion the bricks were taken from the water and their surfaces examined in order to see what change, if any, had taken place in the coating. In some cases the coating had softened, in some shrivelled, and in one case the coating, naphtha and a paraffin-like substance, which before immersion was evidently well into the pores of the brick, had gradually worked out into the water. " The nature of the substances tested varied greatly. Some were in the nature of paints and varnishes, and were retained mostly upon the surfaces of the bricks. To this class belonged the materials used in tests marked A, B, D, G, L, O, P, and Q. Other substances were more in the nature of a paste or coating applied upon the surface of the bricks. In this class may be included the substances used in tests marked C, I, K, N, R, S, T, and U. Another class of substances was supposed to soak into the bricks, and by filling the pores exclude moisture. To this class belonged the substances used in tests E, F, and J. Other coat- ings consisted of two substances, which, when combined, were supposed to form an insoluble compound or compounds which would fill up the pores of the brick. The tests of this class are marked H, M, and V. " Some substances which were submitted for test could be applied to the bricks only by soaking, and so were not available. Some bricks offered for test were soaked full of the so-called waterproofing, and of course would not absorb water or anything else while in that condition, as the pores of the brick were already filled. Many resins, gums, and oils were tested, but they were of no practical use. " Pitch, asphaltum, &c., were objectionable, because of their odour and colour. The results of the tests giving the most favourable results are shown in the following tables. INSULATION. 347 TESTS OF WATERPROOFING BRICK. 1 2 3 4 5 11 12 Weight Grams. Compared to Bare Briek. Sample. Bare Brick. Coated Brick. a-** Per Cent. In- crease by Coat- ing and Water. Per Cent. Increase by Water. A - 630-32 639-10 8-78 1-39 1-63 0-24 B - 556-71 571-11 14-40 2-59 3-11 0-52 C - 578-43 581-92 3-49 0-60 1-14 0-89 D - 527-80 537-70 9-90 1-88 2-84 0-97 E - 616-10 637-60 21-50 3-49 5-61 1-62 F - 633-80 706-87 73-07 11-53 13-75 2-23 G - 584-40 588-92 4-52 0-77 3-23 2-46 H - - 499-52 551-00 51-48 10-31 13-36 3-07 I - 504-12 523-40 19-28 3-82 6-93 3-10 J - 666-94 670-07 3-13 0-47 3-94 3-47 K - 607-29 610-90 3-61 0-59 4-19 3-59 L - 519-68 527-34 7-69 1-48 5-66 4-18 M - 652-50 692-99 40-49 6-21 10-53 4-33 N - 510-20 529-10 18-90 3-70 8-35 4-65 - 570-87 586-20 15-33 2-69 7-71 5-03 P - 496-20 503-00 6-80 1-37 7-16 579 Q - - 502-87 515-12 12-25 2-44 8-85 6-37 K - ... 543-60 , 1-32 S - 602-20 Compared 1 1-53 T - 606-31 to coated { 1-68 U - 581-16 brick. 2-69 V - 621-85 * 5-17 W - ... X - Y - ... Bare brick 489-04 8 '-68 348 REFRIGERATION AND CdLD STORAGE. TESTS OF WATERPROOFING BRICK. Sample. 6 7 8 9 10 Increased Weight by Absorption of Water. 24 Hours. 48 Hours. 72 Hours. 96 Hours. 120 Hours. A - 0-30 1-10 1-50 B - - - 1-39 2-16 2-49 2-89 C - 1-15 2-18 3-25 3-49 5-13 J) - 1-00 ... 2-88 4-00 5-10 E - - - 2-10 5-55 7-15 9-97 F - 4-75 12-13 12-83 14-13 G - - - 4-88 7-48 9-68 11-43 14-38 H - 7-30 9-70 11-30 13-30 15-32 I ... 3-73 6-33 12-12 15-63 J - - 20-33 21-13 21-63 23-13 K - - - 7-00 8-60 9-30 21-83 L - 3-73 5-78 12 : 68 21-72 M - - - 24-78 ... 27 : 16 28-24 N - - - 23-10 ... 23-80 23-72 - 26-98 28-00 28-00 23-70 P - 24-85 28-75 28 : 71 28-72 Q - - - 29-08 36 : 70 31-28 32-03 R - 3-72 5-00 6-15 7-15 8 ... 3-10 5-55 7-35 9-20 T - - - 2-35 4-69 8-07 10-21 U - - - 6-46 9-69 12-69 15-64 V - - - 21-15 29-60 31-02 32-15 W - - - X - Y - Bare brick 21 '-26 39 : 69 39 : 69 42 : 43 INSULATION. 349 TESTS OP WATERPROOFING BRICK. 1 2 3 4 5 6 7 8 9 10 11 12 Weight Grams. Increase in Weight by Absorption of Water. Compared to Bare Brick. ^ j "a _o m PQ 1 trt ti) C II I Hours. o ffi 1 g 1 ""'5 * *.S CAJ 1 O c! ll oo (M S I J5* A - 630-32 639-10 8-78 1-39 0-30 1-10 1-50 1-63 0-24 B - 556-71 571-11 14-40 2-59 1-39 2-16 2-49 2-89 3-11 0-52 C - 578-43 581-92 3-49 0-60 1-15 2-18 3-25 3-49 5-13 1-14 0-89 D - 527-80 537-70 9-90 1-88 1-00 2-88 4-00 5-10 2-84 0-97 E - 616-10 637-60 21-50 3-49 2-10 5-55 7-15 ... 9-99 5-11 1-62 F - 633-80 706-87 73-07 11-53 4-75 12-13 12-83 14-13 13-75 2-23 G - 584-40 588-92 4-52 0-77 4-88 7-48 9-68 li V 43 14-38 3-23 2-46 H - 499-52 551-00 51-48 10-31 7-30 9-70 11-30 13-30 15-32 13-36 3-07 I - 504-12 523-40 19-28 3-82 3-73 6-33 12-12 15-63 6-93 3-10 J - 666-94 670-07 3-13 0-47 20-33 21-13 21-63 23-13 3-94 3-47 K - 607-29 610-90 3-61 0-59 7-00 8-60 9-30 2l'-83 4-19 3-59 L - 519-68 527-34 7-69 1-48 3-76 5-78 . . 12-68 21-72 5-66 4-18 M - 652-50 692-99 40-49 6-21 24-78 27-16 28-24 10-53 4-33 N - 510-20 529-10 18-90 3-70 23-10 23-80 23-72 8-35 4-65 - 570-87 586-20 15-33 2-69 26-98 28-00 28-00 28-70 7-71 5-03 P - 496-20 503-00 6-80 1-37 24-85 28-75 28-71 28-72 7-16 5-79 Q 502-87 515-12 12-25 2-44 29-08 30-70 31-28 32-03 8-85 6-37 R - ... 543-60 3-72 5-00 6-15 7-15 ... ... *l-32 S - 602-20 3-10 5-55 7-35 9-20 ... *l-53 T - 606-31 2-35 4-69 8-07 1021 *l-68 U - 581-16 6-46 9-69 12-69 15-64 ... *2-69 V 621-85 '... 21-15 29-60 31-02 32-15 *5-17 W - X - Y - Bare >rick 489-04 21-26 39-69 39-69 42-43 *8-68 1 gram equals 15 "43 grains ; 28 "35 grams equals 1 ounce avoirdupois. * Compared to coated brick. 350 REFRIGERATION AND COLD STORAGE. KEY TO TESTS OF WATERPROOFING BRICK. A. Bay State air and waterproofing - - 3 coats. B. Red mineral paint, ground in oil - 2 coats. C. Spar varnish with plaster of paris - 2 coats. D. Spar varnish - - 2 coats. E. New York sample, No. 2 Soaked. F. New York sample, No. 1 Soaked. G. Shellac - 1 coat. H. Portland cement, 1 coat ; soap and alum, 3 coats - 4 coats. I. White enamel paint - 3 coats. J. Paraffin in naphtha - 3 coats. K. Hot paraffin - 3 coats. L. Water paint 3 coats. M. Portland cement mixed with CaCl 2 , 1 coat ; water glass, 3 coats - - 4 coats. N. Portland cement - 2 coats. O. Black varnish, No. 2 3 coats. P. Spar varnish - 1 coat. Q. Black varnish, No. 1 3 coats. R. Waterproofing, No. 1. (A putty-like substance applied to surface of brick.) S. Waterproofing, No. 4. Similar to "R." T. Waterproofing, No. 3. Similar to "R." U. Waterproofing, No. 2. Similar to " R." V. Bi-chromate potash and glue exposed to sunlight. Bare brick - No coating. " In regard to the result of the tests it is worthy of remark that some of the substances that have been considered as among the best waterproof materials proved to be either of little value or very inferior to some of the other substances. "The Sylvester process, H, soap and alum, proved to be of little value, even when applied to a surface made as smooth as possible with Portland cement. This process was also tried without the cement, but was even less effective. Hot paraffin has often been used to water- proof walls ; but, under the conditions of these tests, it proved to be very far from waterproof. Portland cement is another substance which did not prove to be as good as its reputation." WALLS FOR COLD STORES. The following materials and dimensions have been used and are recommended for walls of cold chambers : Walls at the St Katherine's Dock, London, were formed of up- INSULATION. 351 rights, 5J in. by 3 in., fixed upon the floor joists or bearers, and having an outer and an inner skin attached thereto ; the former consist- ing of 2-in. boards, and the latter of two thicknesses or layers of 1^-in. boards, with an intermediate layer of specially-prepared brown paper. The 5 in. clearance or space between the inner and outer skins of the walls and roof was likewise filled with wood charcoal, carefully dried. 14 in. brick wall, 3J in. air space, 9 in. brick wall, 1 in. layer of cement, 1 in. layer of pitch, 2 in. by 3 in. studding, layer of tar paper, 1-in. tongued and grooved boarding, 2 in. by 4 in. studding, 1-in. tongued and grooved board, layer of tar paper, and, finally, 1-in. tongued and grooved boarding, the total thickness of these layers or skins being 3 ft. 3 in. 36 in. brick wall, 1 in. layer of pitch, 1 in. sheathing, 4 in. air space, 2 in. by 4 in. studding, 1 in. sheathing, 3 in. layer of mineral or slag wool, 2 in. by 4 in. studding, and, finally, 1 in. sheathing; total thickness, 4 ft. 7 in. 14 in. brick wall, 4 in. pitch and ashes, 4 in. brick wall, 4 in. air space, 14 in. brick wall ; total thickness, 3 ft. 4 in. 14 in. brick wall, 6 in. air space, double thickness of 1-in. tongued and grooved boards, with a layer of waterproof paper between them, 2 in. layer of the best quality hair felt, second double thickness of 1-in. tongued and grooved boards, with a similar layer of paper between them ; total thickness, 2 ft. 2 in. 14 in. brick wall, 8 in. layer of sawdust, double thickness of 1-in. tongued and grooved boards, with a layer of tarred waterproof paper between them, 2 in. layer of hair-felt, second double thickness of 1-in. tongued and grooved boards, with a similar layer of paper between them ; total thickness, 2 ft. 4 \ in. Brick wall, 3 in. scratched hollow tiles, 4 in. silicate cotton or slag- wool, 3 in. scratched hollow tiles, and layer of cement plaster. Brick wall, 1 in. air spaces between fillets of strips, 1-in. tongued and grooved boarding, two layers of insulating paper, I 7 in. tongued and grooved boarding, 2 in. by 4 in. studs, 16 in. apart, spaces filled in with silicate cotton, 1-in. tongued and grooved boarding, two layers of insulating paper, air spaces between fillets, or strips 1 in. by 2 in. spaced 16 in. apart from centres, 1-in. tongued and grooved boarding, two layers of insulating paper, and 1-in. tongued and grooved boarding. Brick or stone wall, well coated on inside with pitch or asphaltum, 2 in. by 3 in. studding, 24 in. centres, spaces between filled in with silicate cotton, f-in. rough tongued and grooved boarding, two layers 352 REFRIGERATION AND COLD STORAGE. waterproof insulating paper, j-in. rough tongued and grooved board- ing, 2 in. by 3 in. studding, 24 in. centres, in spaces between, j-in. rough tongued and grooved boarding, two layers of waterproof insulating paper, j-in. rough tongued and grooved boarding, 2 in. by 3 in. studding, 24 in. centres, spaces between filled in with silicate cotton, J-in. rough tongued and grooved boarding, two layers of waterproof insulating paper, and j-in. tongued and grooved match-boarding. Paper to be laid one-half lap and cemented at all joints. Brick wall, 2 in. air space, 2 in. thicknesses of tongued and grooved boards with three layers of paper between, 2 in. air space, 2 in. thick- nesses of tongued and grooved boards with three layers of paper between, 2 in. air space and 2 in. thicknesses of tongued and grooved boards with three layers of paper between. Brick wall, well coated with pitch, 2 in. air space, 2 in. thicknesses of tongued and grooved boards with three layers of paper between, 2 in. space filled with slag-wool or cork, 2 in. thicknesses of tongued and grooved boards, with three layers of paper between, 2 in. space filled with slag-wool or cork, 2 in. thicknesses of tongued and grooved boards, with three layers of paper between. Shelving should be fixed horizontally in the spaces packed with slag- wool or cork at about 16 in. apart. Brick wall, 1 in. air space, f-in. match-boarding, 9 in. slag- wool or silicate cotton, layer of insulating paper and j-in. match-boarding. Brick wall, 1 in. air space, 6 in. slag-wool or silicate cotton, 1 in. silicate of cotton slab, layer of insulating paper, \ in. air space, and j-in. match -boarding. Brick wall, 1 in. air space, 1 in. silicate of cotton slab, 4 in. silicate of cotton, 1 in. silicate of cotton slab, J-in. air space, and f-in. match-boarding. Brick wall, well coated with pitch, 2 in. air space, J-in. tongued and grooved boarding, two layers of paper, J-in. tongued and grooved boarding, 4 in. slag-wool or silicate cotton, J-in. tongued and grooved boarding, two layers of paper, J-in. tongued and grooved boarding, 2 in. air space, J-in. tongued and grooved boarding, two layers of paper, and J-in. tongued and grooved boarding. Brick wall, 2 in. air space, J-in. tongued and grooved boarding, two layers of paper, J-in. tongued and grooved boarding, 2 in. air space, J-in. tongued and grooved boarding, two layers of paper, and J-in. tongued and grooved boarding. Brick wall, 2 in. air space, J-in. tongued and grooved boarding, one layer of paper, 4 in. slag- wool or silicate cotton, J-in. tongued and INSULATION. 353 grooved boarding, one layer of paper, 4 in. air space, |~in. tongued and grooved boarding, two layers of paper, and |-in. tongued and grooved boarding. Brick wall, layer of pitch, J-in. tongued and grooved boarding 2 in. air space, f-in. tongued and grooved boarding, one layer of paper, 3 in. cork dust, f-in. tongued and grooved boarding, two layers of paper, and f-in. tongued and grooved boarding. Brick wall, 2J in. air space ventilated by air bricks every 5 ft. in all directions, 1-in. tongued and grooved boarding, layer of Willesden and brown paper, 1-in. tongued and grooved boarding, 12 in. charcoal supported by horizontal shelving 28 in. centres apart, 1-in. tongued and grooved boarding, two thicknesses of brown paper, and 1-in. tongued and grooved boarding. Wall of cold storage room when made of wood : 2 in. thicknesses of tongued and grooved boarding with three layers of paper between, 2 in. air space, 2 in. thicknesses of tongued and grooved boarding with three layers of paper between, 2 in. air space, 2 in. thicknesses of tongued and grooved boarding with three layers of paper between, 2 in. air space, 2 in. thicknesses of tongued and grooved boarding with three layers of paper between, 8 in. slag-wool or silicate cotton, and 1-in. tongued and grooved boarding. 2 in. boards, 5J in. by 3 in. uprights, spaces between filled with carefully dried wood charcoal, IJ-in. boarding, layer of insulating paper, and IJ-in. boarding. Outside siding, two layers of insulating paper, 1-in. tongued and grooved boarding, 2 in. by 6 in. studdings, 16 in. apart from centres, 1-in. tongued and grooved boarding, two layers of insulating paper, 1-in. tongued and grooved boarding, 2 in. by 4 in. studding 16 in. apart from centres, spaces filled in with silicate cotton, 1 in. tongued and grooved boarding, two layers of insulating paper, 2 in. by 2 in. fillets or strips 16 in. apart from centres, 1-in. tongued and grooved boarding, two layers of insulating paper, and 1-in. tongued and grooved boarding. DIVISIONAL PARTITIONS FOR COLD STORES. Tongued and grooved match-boarding, wire netting, 6 in. silicate of cotton or slag-wool, wire netting, tongued and grooved match- boarding. The object of the netting is to render the partition fire- proof by supporting the silicate of cotton after the match-boarding might have burnt away. |-in. match-boarding, J in. air space, 1 in. silicate cotton slab, 23 354 REFRIGERATION AND COLD STORAGE. 4 in. of silicate of cotton or slag-wool, 1 in. silicate of cotton slab, |-in. air space, and 1 in. silicate of cotton slab. 2 in. tongued and grooved boarding with three layers of paper between, 2 in. silicate of cotton or cork, 2 in. tongued and grooved boarding with three layers of paper between, 2 in. silicate of cotton or cork, 2 in. tongued and grooved boarding with three layers of paper between. f-in. tongued and grooved boarding, two layers of paper, J-in tongued and grooved boarding, 4 in. silicate cotton or slag-wool, f -in. tongued and grooved boarding, 2 in. air space, J-in. tongued and grooved boarding, two layers of paper, and J -in. tongued and grooved boarding. f-in. tongued and grooved boarding, two layers of paper, j-in. tongued and grooved boarding, 6 in. silicate of cotton or slag-wool, J-in. tongued and grooved boarding, two layers of paper, |-in. tongued and grooved boarding, 2 in. air space, ^-in. tongued and grooved boarding, two layers of paper, and f -in. tongued and grooved boarding. |~in. tongued and grooved boarding, 2 in. silicate cotton or slag wool, J-in. tongued and grooved boarding, 2 in. air space, |-in. tongued and grooved boarding, two layers of paper, and f-in. tongued and grooved boarding. |-in. tongued and grooved boarding, two layers of paper, f-in. tongued and grooved boarding, 2 in. air space, f-in. tongued and grooved boarding, two layers of paper, and J-in. tongued and grooved boarding. J-in. tongued and grooved boarding, two layers of paper, |-in. tongued and grooved boarding, 8 in. silicate cotton or slag-wool, f-in. tongued and grooved boarding, two layers of paper, and f-in. tongued and grooved boarding. ^-in. tongued and grooved boarding, two layers of paper, J-in. tongued and grooved boarding, 4 in. silicate cotton or slag-wool, f-in. tongued and grooved boarding, two layers of paper, and J-in. tongued and grooved boarding. |-in. tongued and grooved boarding, two layers of paper, |-in. tongued and grooved boarding, 2 in. hair felt, |-in. tongued and grooved boarding, 2 in. silicate cotton or slag-wool, J-in. tongued and grooved boarding, two layers of paper, and J-in. tongued and grooved boarding. INSULATION. 355 FLOORING FOR COLD STORES. 2 in. flooring, two layers of paper, J-in. tongued and grooved board- ing, 2 in. air space between fillets or scantlings, J-in. tongued and grooved boarding, 12-in. joists, space between packed with silicate cotton or slag- wool, J-in. tongued and grooved boarding, two layers of paper, J-in. tongued and grooved boarding, 2 in. air space between fillets or scantlings, J-in. tongued and grooved boarding, two layers of paper, and J-in. tongued and grooved boarding. 2 in. cement, 3 in. concrete, J-in. tongued and grooved boarding, two layers of paper, 2 in. flooring, 4 in. silicate cotton between fillets or scantlings, J-in. tongued and grooved boarding, two layers of paper, 2 in. flooring boards on fillets or scantlings set in concrete. 2 in. asphalte, f-in. tongued and grooved boarding, two layers of paper, |-in. tongued and grooved boarding, 2 in. air space between scantlings, |-in. tongued and grooved boarding, 3 in. silicate cotton or slag-wool between fillets or scantlings, f-in. tongued and grooved boarding, 2 in. air space between fillets or scantlings, concrete. 1 in. asphalte, 2 in. concrete, J in. pitch, 2 in. concrete, brick arches. 1^-in. tongued and grooved flooring boards, layer of insulating paper, 2 in. by 9 in. joists 12 in. centres apart, spaces filled with sili- cate cotton or slag-wool, wire netting, layer of insulating paper, |-in. match -boarding on 2 in. by 2 in. fillets or scantlings, air spaces between existing wooden or concrete flooring. The wire netting secured to the underside of the joists serves to retain the silicate cotton in case of fire. 1-in. tongued and grooved boarding, three layers of insulating paper, 1-in. tongued and grooved boarding, 2 in. by 9 in. joists, spaces between filled with silicate cotton or cork, 1-in. tongued and grooved boarding, three layers of insulating paper, and 1-in. tongued and grooved boarding. IJ-in. tongued and grooved flooring boards, layer of insulating paper, 2 in. by 9 in. joists, 12 in. centres apart, spaces between filled in with silicate cotton or slag-wool, 1 in. silicate cotton slab on in. by 2 in. fillets, air spaces between, and |-in. match-boarding. The 1 in. sili- cate of cotton slab is nailed on the underside of joists and is claimed to render the floor fire-proof, and to prevent radiation through the joists. 2 in. matched flooring, two layers of insulating paper, 1 in. matched sheathing, 4 in. by 4 in. sleepers 16 in. apart from centres, spaces between filled in with silicate cotton, double 1 in. matched sheathing 356 REFRIGERATION AND COLD STORAGE. with twelve layers of paper between, and 4 in. by 4 in. sleepers 1 6 in. apart from centres embedded in 12 in. of dry underfilling. Ground, concrete, layer of asphalte, 1-in. tongued and grooved match-boarding w T ell tarred, two layers of stout brown paper, 1-in. tongued and grooved match-boarding, floor joists 3 in. by 11 in. spaced 21 in. apart, binder joists 11 in. by 4 in., bearing edges of floor joists protected by strips of hair-felt J in. thick and spaces between joists filled in with flake charcoal, and 1^-in. tongued and grooved flooring boards. The floors of the cold storage chambers built at the St Katherine Dock, London, were constructed as follows : On the concrete floor of the vault, as it stood originally, a covering of rough boards 1J in. in thickness were laid longitudinally. On this layer of boards were then placed transversely bearers formed of joists 4J in. in depth by 3 in. in width, and spaced 21 in. apart. These bearers supported the floors of the storage chamber, which consisted of 2J-in. battens tongued and grooved. The 4J-in. wide space or clearance between this floor and the layer or covering of rough boards upon the lower concrete floor was filled with well-dried wood charcoal. FLOORING FOR ICE HOUSES. Floor to incline 3 in. towards central drain, and cross channelled fillets or scantlings on 1^ in. flooring, 2 in. cement, 6 in. concrete, ground. 1-in. tongued and grooved match-boarding, three layers of paper, 1-in. tongued and grooved match-boarding (to incline 3 in. towards central drain) on fillets or scantlings, air spaces between, 1-in. tongued and grooved match-boarding, three layers of paper, 1-in. tongued and grooved match-boarding, 2 in. by 9 in. joists, spaces between filled with 4 in. silicate of cotton or slag-wool kept in position by j-in. boards secured by cleats to joists. CEILINGS FOR COLD STORES AND ICE HOUSES. 1-in. tongued and grooved match-boarding, three layers of insulat- ing paper, 1-in. tongued and grooved match-boarding, 2 in. air spaces between strips or fillets, 1-in. tongued and grooved boarding, three layers of insulating paper, 1-in. tongued and grooved boarding, joists, spaces between filled with silicate cotton or cork, 1-in. tongued and grooved match-boarding, three layers of insulating paper, and 1-in. tongued and grooved match-boarding. INSULATION. 357 Insulated flooring, joists, f-in. tongued and grooved match-board- ing, two layers of insulating paper, -in. tongued and grooved match - boarding, 2 in. spaces between strips or fillets filled in with silicate cotton or cork, |-in. tongued and grooved match-boarding, three layers of insulating paper, and -in. tongued and grooved match-boarding. 1-in. tongued and grooved boarding, two thicknesses of brown paper, 1-in. tongued and grooved boarding, joists with spaces between packed with silicate cotton, 1-in. tongued and grooved boarding, Willesden and brown paper, 1-in. tongued and grooved boarding. Concrete floor, 3 in. book tiles, 6 in. dry underfilling, double space hollow tile arches and layer of cement plaster. Fig. 225. Door for Cold Store, with Taylor's Patent Fittings. Double 1 in. floor with two layers of insulating paper between, 2 in. by 2 in. strips or fillets 16 in. apart from centres, spaces filled in with silicate cotton, two layers of insulating paper, 1-in. tongued and grooved match-boarding, 2 in. by 2 in. strips 16 in. apart, spaces filled in with silicate cotton, two layers of insulating paper, 1-in. tongued and grooved match-boarding, joists and double 1-in. flooring with two layers of in- sulating paper between. DOOR INSULATION. A weak point in most cold storage rooms is the door ; these are usually constructed on the wedge principle, and several simple forms 358 REFRIGERATION AND COLD STORAGE. are shown in the illustrations on this and succeeding pages. Even when properly designed and carefully made from the best, well- fo , -s *c. HOARD* rofl CE *<"*' COLO STO, .4G.BOAROS AND ICC . 4 B. f>AP t R 6ETWKNJ EILINCOF ORAGE ROOMS MOUSE. "TmCKNEsscsor ;:J.:PETWEE "THICKNESSES OF fctltXpKWt FOR WALL Of COLD STORAGE ROOM AND ICE HOUSE MADE OF BRICK. . t* THICKNESSES OF T.4 C BOARDS P. 8. PAPER BtTAttN IR SPACE FILLED AS SHOWN HICKNESStS OF T. A C BOARDS .< P. 4 B. PAPER BETWtEN IR SPACt FllLEO AS SHOWN HICKNESSES OF T 4 C. BOARDS .1 P. 4 8. PAPtR OCTWttJI rOft INTEflHEDIATE FLOORS. _ 5'THICKNESStiOf T.* C. IOAR ^_J- ~ .. P. . PAPtH Figs. 226 and 227. Frick Company Method of Insulating a Cold Store. Vertical and Horizontal Sections. seasoned timber, the doors of cold storage rooms are very apt to give trouble on account of the extreme temperatures to which they are INSULATION. 359 I'THICK. T. i o. BOAXCS )' PAPER t>R SPACE "THICK. I. AC. DOAROS ,' ' PAPE WOOL JCE HOUSE FLOOR WHEN MADE OF WOOD A ICE HOUSE FLOOR WHEN LAID IN CEMENT FLOOR TO INCLINE a'TOWAROS tHE CENTER -T INSULATION OF JOISTS V, ' , g S-ji?*??! ^V'-.--":'"' S -It MINERAL WOOLORCOBR -2"TH1CK. t. A C. BOARDS -3^ > PAPER w -4*MINeRAI. WOOL OR CORK WINDOW SASH AND FRAME IN STORAGE ROOMS^. TH1CKNE8SE9(?F T< 4G BOARM km SPACE WHEN MADE OF WOOD OF COLD S THICKNESSES OF T. i G. BOARDS ii 1PAPER BETWEEN SPACE Z'THICK. OF T. A c. BOARDS V - < PAPER BETWEEN B'AIR SPACE THICK. OF T. ft C. BOARDS i PAPER OR MINERAL WOOL AS SHOW .OTJGITUDINAL SECTION OF DOOR IN PARTITION CROSS SECTJON DOOR THROUGH WALL AND INSULATION Figs. 228 to 235. Frick Company Methods of Wall, Floor, Ceiling, Partition, Door, and Window Insulation. 360 REFRIGERATION AND COLD STORAGE. subjected and from the absorption of moisture from the air. As there can be no doubt that considerable loss is experienced through badly- made and poorly-fitting doors, too much care cannot be expended in securing the best possible workmanship and efficient and easily mani- pulated fittings. Fig. 225 shows a type of door fitted with Taylor's patent door-fittings, of which Mr John Straiten, Liverpool, is the sole maker. A door much used in America is Stevens' patent, which is made up of five thicknesses of insulated and waterproofed paper, ^ in. prepared mineral or slag wool, three air spaces, and four thicknesses of wood. Amongst the advantages claimed for this type of door is that it will not frost through with zero temperature. A canvas cushion on the bottom prevents the cold air from escaping at that point. The door will not stick. It closes quite tight on the hinge edge. The fastening is of a special pattern and is for both edges of the door. It is claimed to shut as tight as a cross-bar would if it were wedged up, and can be opened either from the exterior or interior. A special form of door, designed by the author for use in hotels, or elsewhere, where the cold storage room or chamber has to be frequently entered, has been described in a previous chapter. Other insulations for doors are : 1-in. tongued and grooved match-boarding, three layers of insulating paper, 1-in. tongued and grooved match-boarding, 2 in. by 1 in. fillets or strips with spaces between filled in with silicate cotton or cork, 1-in. tongued and grooved match-boarding, three layers of insulating paper, 1-in. tongued and grooved match-boarding. 2 in. by 1 in. fillets or strips, spaces between filled in with silicate cotton or cork, 1-in. tongued and grooved match-boarding, three layers of insulating paper, and 1-in. tongued and grooved match-boarding. 1-in. tongued and grooved match-boarding, two layers of insulating paper, 1-in. tongued and grooved match-boarding, 12 in. space filled in with silicate cotton, 1-in. tongued and grooved match-boarding, two layers of insulating paper, and 1-in. tongued and grooved match- boarding. WINDOW INSULATION. Windows are better dispensed with in cold stores and artificial light resorted to ; where present, three sashes spaced a few inches apart and glazed at both sides should be used. TANK INSULATION. Tank sides : 4 in. air space between studding, 1-in. tongued and grooved match-boarding, three layers of insulating paper, 1-in. tongued INSULATION. 361 and grooved match-boarding, 4 in. space filled with cork, 1-in. tongued and grooved match-boarding, three layers of insulating paper, 1-in. tongued and grooved match -boarding, 2 in. air space, 1-in. tongued and grooved match-boarding, three layers of insulating paper, and 1-in. tongued and grooved match-boarding. Bottom, 1 in. space between strips, fillets or studding, well tarred before tank is placed in position, 1-in. tongued and grooved match-boarding, three layers of insulating SPACE FILLED WITH con 2X4 STUDDING 30 CEN. 8*X 2" 11 30* ii *"x 4* * 10* AIR SPACC- TMICKNE8SES OF T.1G. BOARDS ' . PAPER SPACE FILLED WITH CORK THICK. '(. A G. BOARDS PAPER. BETWEE AIR SPACE THICK. T. A G. BOARDS SPACE FILLED WITH CORK Fig. 236. Frick Company Method of Tank Insulation. Vertical Section. paper, 1-in. tongued and grooved match-boarding, 1 in. airspace between strips, fillets or studding, 1-in. tongued and grooved match-boarding, three layers of insulating paper, 1-in. tongued and grooved match - boarding, 2 in. by 9 in. joists, spaces between filled with cinders. Tank, 2 in. air space between fillets, f-in. tongued and grooved match-boarding, two layers of insulating paper, |-in. tongued and grooved match-boarding, 4 in. silicate cotton or slag- wool, J-in. tongued 362 REFRIGERATION AND COLD STORAGE. THICKNESS T. 4 G. PAPER BETWEEN SPACE FOR MINERAL WOOV /THICKNESS T. 4 O lco::l : I : I ::co::co I :l 12 CO gg . TEMPERATURES FOR COLD STORAGE. 395 CHAPTER XVI MAKINE KEFKIGEKATION Carbonic Acid Machines Ammonia Machines Cold-Air Machines Arrangement of Cargo Holds and Stores Ice-Making on Board Ship Barges. MARINE refrigeration offers considerably more difficulties, both as regards the machinery, and likewise with respect to the installation of the cold chambers, than is the case with land installations. As regards the machinery, in the first place, the space at command is necessarily limited, and consequently it is absolutely necessary that the design should be such as to occupy the minimum of room, whilst affording the maximum of efficiency. The agent or medium employed should likewise be one of a non- inflammable nature, and also one having no deleterious action on copper, which metal has to be employed in the condenser in order to enable sea water to be used for cooling purposes. With reference to the insulation, the settlement or shaking down due to the continuous vibration experienced on ship-board has to be contended with. For this reason an excellent material to use for insulating purposes in marine installations is what is known as " Non- pareil " cork, which is largely employed in the American Navy. This material consists of granulated cork, made by compressing cork chips under hydraulic pressure in iron moulds, and then heating the mass while in the mould to a temperature of about 500 Fahr. This treat- ment has the effect of liquefying the natural gum of the cork, and forming the interstices between the granules into small closed air spaces. On the cooling of the moulds the gum hardens, and the mass becomes, as it were, a solid sheet of cork. The weight of " Nonpareil " cork is only 1 Ib. per square foot, and it is consequently about the lightest insulating material in use. It is said to be 13 per cent, superior, as a non-conductor of heat, to hair-felt, and 40 per cent, superior to sawdust. Slag, or mineral wool, or silicate cotton, is also used very extensively, and with great success for marine work. As regards the most suitable system of refrigerating machine for 396 MARINE REFRIGERATION. 397 use on board ship, a wide diversity of opinion still exists. In spite of comparing unfavourably, as regards efficiency, with machines using agents possessed of greater latent heat, cold-air machines might still be advantageously used for short voyages, and where coal could be obtained cheap. There are no chemicals to be carried, no danger from bursting of pipes or joints giving out, and the machine is com- paratively simple and easily managed. Of machines working on the compression system, and employing a t refrigerating agent of a more or less volatile nature, carbonic acid machines offer advantages which have caused them to be very largely employed for marine purposes, a fact which has been proved in a practical manner by Messrs J. & E. Hall, Ltd., alone having fitted over 1800 machines working on this system on board ship. The qualities which render CO 2 particularly suitable for use on ship-board are : First, that this agent admits of a much smaller com- pressor being employed relatively to the refrigerating power produced ; second, that having no corrosive action on any of the metals, it thereby allows, as above mentioned, of copper being used in the condenser ; and third and lastly, but not least, it is not only non-inflammable, but has the power to extinguish fire, and is therefore perfectly free from danger in this respect. As regards the danger to life through an escape of this gas, its specific gravity being greater than that of air (CO., spec. grav. 1*529 air = 1) causes it to fall to the lowest level, and in practice it is found that no danger is to be apprehended from the escape of a moderate quantity of CO., if the space be not unduly confined and is fairly well ventilated. For this reason the Board of Trade's instructions to surveyors, issued in June 1901 re refrigerat- ing machines, contains the following : " The surveyors are therefore informed that, unless they are aware of any special reasons to the con- trary, refrigerating machines in which carbonic anhydride is employed as the working agent may be placed in the engine-rooms of steam- ships, provided the weight of the charge which would be released by a breakdown of the machine, or of one portion of a duplex machine, does not exceed 200 Ibs. " When it is proposed to fit a machine using a greater charge than this is an engine-room, full particulars of the case, including size, and method of ventilating the compartment, and weight of charge pro- posed, should be submitted for consideration." The principles upon which the marine types of refrigerating machines work are naturally precisely the same as those employed for service on land, and therefore the differences are merely of a 398 REFRIGERATION AND COLD STORAGE. structural nature, adapted to render them .more especially suitable to the construction of vessels. It is purposed, therefore, in this chapter, to merely give a few examples of machines especially designed for marine purposes, referring readers for further particulars as to the special distinctive details of construction adopted by the various makers to the more lengthy and complete descriptions given of their land types of machines. Fig. 282 shows one of J. & E. Hall's carbonic acid machines of the horizontal duplex marine type, which has been specially designed for large installations on board ship. This machine is fitted with a compound steam cylinder, the high-pressure cylinder being on one side and the low-pressure cylinder on the other, a double-acting com- pressor being driven by a tail-rod from each cylinder. The two machines are so arranged that either both sides can be worked together, or, if desired, one half, that is to say, one compressor with its condenser and evaporator can be disconnected, when the other half can be worked by itself. Each compressor delivers the compressed carbonic acid through an independent condenser, which is placed in the base of the machine or built separately as may be found to be most convenient, and in which sea water is circulated round the condenser pipes through which the carbonic acid passes. This type of machine is also built in pairs mounted on the same base or bed-plate, with compound steam cylinders, the high-pressure cylinder being located on the one side, and the low-pressure cylinder on the other. The two compressors are, in this type, driven by tail- rods from the steam cylinders, and the cranks are placed at right angles, an arrangement which tends to ensure an even turning move- ment. Each compressor delivers the compressed carbonic acid to an independent condenser, which is usually placed in the base of the machine, and in which sea water is circulated round the condenser pipes through which the carbonic acid passes. In connection with each side of the machine a separate evaporator or refrigerator is pro- vided, which consists, as in the land type, of coils of pipes, in which the liquid carbonic anhydride evaporates or gasifies, and which coils are enclosed in a steel casing, in which the brine is circulated by means of pumps. The brine thus cooled is, in one arrangement, circulated through electrically-welded grids of piping, each containing about 200 feet of pipe, which grids are divided into sections, each section having a separate flow and return from the evaporator or refrigerator, and valves being provided for regulating the quantity of cold brine in each section as required by the temperature in the holds^ MARINE REFRIGERATION. 399 Fig. 282. Hall Horizontal Duplex Marine Type of Steam-driven Carbonic Acid Compression Machine. 400 REFRIGERATION AND COLD STORAGE. The grids are placed on the under side of the decks over the holds to Fig. 283. Hall Vertical Marine Type of Steam-driven Carbonic Acid Compression Machine. be refrigerated, preferably between the deck beams, so as to occupy no valuable space, and to be protected from damage. MARINE REFRIGERATION. 401 suitable In another arrangement the brine is passed through a battery of pipes, over which air is drawn by fans, and is through the holds to be cooled. In Fig. 283 is illustrated one of the vertical duplex marine types of machines built by the same firm. This pattern of machine is especially designed for preserving provisions on passenger steamers and on steam yachts, and for making ice. The machine is fitted with compound steam cylinders and two compressors, in connection with each of which Fig. 284. Hall Small Marine Type of Steam-driven Carbonic Acid Compression Machine. Vertical Central Section. latter is a condenser and an evaporator or refrigerator, there being thus two entirely independent complete carbonic acid machines, either of which can be disconnected, and the remaining machine run with the compound engine. Smaller marine-type machines (Fig. 284) are also made by this firm, having a single vertical steam cylinder, and the compressor arranged alongside of it, both being fixed to a casting containing the condenser coils, which latter are made of copper, and behind which casting is 26 402 REFRIGERATION AND COLD STORAGE. another secured to it, and containing the evaporator or refrigerator coils. Turning to machines working on the ammonia compression system, Fig. 285 shows a marine type of the De La Yergne machine. It is a vertical single-acting compressor, actuated by a high-pressure horizontal steam engine, fitted with a special governor, which admits Fig. 285. De La Vergne Vertical Single- Acting Marine Type of Ammonia Compression Machine. of the steam supply being determined for wide ranges of speeds when required, say for any speed between 30 and 300 revolutions per minute, without interfering with the running or stopping the machine. The construction of the compressor cylinder is identical with that illustrated in the enlarged sectional view, Fig. 17. In the marine type of Linde machine a single compound ammonia MARINE REFRIGERATION. 403 compressor is employed, which, as in the case of the land type of machine, is also driven by means of a tandem compound engine. The ammonia condenser is situated below the compressor, and is fitted with sets of endless coils or worms. By the use of a compound compressor, that is to say, one wherein the com- pression of the ammonia gas is effected in two stages, the loss from re-expansion of gas left in the clearances is com- pletely got rid of, as such loss is experienced in the low pressure compressor cylinder only, none taking place in the high-pressure compressor cylinder. Figs. 286 and 287 show Fig 2 86.-Puplett Horizontal Marine two ammonia machines of the Type of Steam-driven Ammonia Compres- horizontal marine type, de- sion Machine, signed by Mr S. Puplett, the first being a horizontal ammonia compressor connected with a vertical engine, all mounted upon the same bed-plate, and the second a corn- Fig. 287. Puplett Horizontal Marine Type of Belt-driven Ammonia Compression Machine. pact form of horizontal belt-driven ammonia compressor, especially designed for marine work. 404 REFRIGERATION AND COLD STORAGE. Fig. 288. Haslam Vertical Self-contained Marine Type of Steam-driven Ammonia Compression Machine, MARINE REFRIGERATION. 405 I ? o g 1 3 I 4 o6 REFRIGERATION AND COLD STORAGE. Fig. 288 shows a vertical self-contained marine type of ammonia compression machine made by the Haslam Foundry and Engineering Co., Ltd., Derby. As will be seen from the illustration, the ammonia compressor, steam engine, separator, condenser, receiver, and water pump are all mounted on the same bed or base plate, and the design Figs. 290 and 291. Kilbourn Horizontal Self-contained Marine Type of Steam-driven Double-Acting Ammonia Compressor. Plan and Eleva- tion, partly in Section. is such that they occupy as small an amount of space as possible, and form a completely self-contained apparatus. The bed-plate is of cast iron, circular in form, contains the ammonia condensing coils, and is made in two parts ; the back part being readily removable for giving access to the condensing coils for cleaning and examination. The front part is strongly constructed and provided with ribs, facings, and MARINE REFRIGERATION. 407 brackets to receive the steam cylinder, ammonia compressor, crank- shaft, and other working parts of the machine. A water pump, shown on the right-hand side of the illustration, and worked by a disc crank on the end of the crank shaft, is provided for circulating w^ater through the condenser, and when desired a brine pump is also fitted. This machine is made in sizes from half-ton ice-making capacity per day up to three tons ice-making capacity per day. The three- ton machine will maintain from 16,000 to 32,000 cub. ft. at 32 Fahr. in ordinary storage, and requires 9 T.H.P. in a temperate climate and 10J I.H.P. in a hot climate. Three hundred gallons of condensing water are required per hour, 55 on and 80 off. The weight of the machine is 103 cwt., and the dimensions 6 ft. 8 in. in depth, 6 ft. in width, and 7 ft. 8 in. in height. Fig. 289 is an illustration showing the latest horizontal marine type of Haslam compound ammonia compressor. This ma- chine consists of a compound engine, and compound ammonia compressors, the gas being thus compressed in two stages. The whole is mounted upon a cast- iron bed-plate which in turn is mounted upon a wrought-iron tank, which latter contains the ammonia condenser coils. The system of cooling employed with this machine is either brine pipes placed in the holds, or the air-blast system ; an installation on the latter plan, which the above firm put into the New Zealand Shipping Co.'s steamer " Ruapehu," consists of a series of direct expansion cooling pipes or coils, placed in nests, over which the air is circulated by means of a powerful fan. The air is cooled in passing through the coils to any desired temperature, is then circulated through the holds, and then returned again to the fan. Figs. 290 and 291 show in plan and in elevation, partly in vertical section, a self-contained marine type of horizontal double-acting am- monia compressor and vertical steam engine, on the Kilbourn system, Fig. 292. Kilbourn Horizontal Double- Acting Marine Type of Belt- driven Ammonia Compressor. 408 REFRIGERATION AND COLD STORAGE. which is extensively used on American steamers. Fig. 292 shows a belt-driven Kilbourn marine type ammonia compression machine. This double-acting horizontal ammonia compression machine is driven by a vertical engine, which is fixed upon the same base or bed- plate in such a manner as to render the complete machine very compact in design, one of sufficient power to keep a storage capacity of 22,000 to 26,000 cub. ft. at a suitable temperature for chilled beef, 40,000 to 44,000 ft. for frozen mutton, or of making about 6 tons of ice per day of twenty-four hours, requiring only a floor space of 10 ft. by 10 ft., including that required for both the refrigerator and the condenser. The compression cylinders are enclosed in water jackets, and are fitted with Webb's patent arrange- ment of suction valves. The stuff ing boxes and glands are of the Kilbourn double pattern, that is, each box is formed with a chamber placed centrally therein, and into which oil is injected constantly for sealing purposes by a small force- pump fixed on the side of the bed- plate, and worked from a lever connected to the compression pump crosshead. The steam cylinder piston rods are coupled by means of forked connecting rods to the same crank pins as those of the compression pumps. Improved forms of gas-tight joints and of a stop-cock or valve, which will be found described on pages 262 to 264, and 253, have been also devised, and were patented in 1882 by the same inventor. The arrangement of the machine illustrated in Fig. 292 is very compact, having been designed with that end more especially in view, Figs. 293 and 294. Marine Type of Ammonia Condenser. Plan and Elevation, partly in Section. MARINE REFRIGERATION. 409 and for which purpose the ammonia condenser is placed underneath the compressor. Figs. 293 and 294 show, in plan and sectional elevation, the marine type of condenser used in conjunction with these machines. The cargo holds of the steamships Campania and Lucania are refrigerated with machines of the Kilbourn type. The meat-carrying chambers in each of these vessels consists of three chambers situated forward on the orlop or lower deck, and having a total capacity of 20,000 cub. ft., which renders them able to carry 2,700 quarters of beef. The chambers are very carefully insulated, the walls consisting, as shown in Fig. 295, first of a double thickness of tongued and grooved boards A, A, having a layer of waterproof paper B between them, next a 2-in, layer of good quality hair-felt c, and another double thickness of tongued and grooved boards D, D, with a similar layer of paper E, between them, and finally an inch air space F between the latter and the inner or iron deck, the whole being well varnished. Fig. 295. Insulation of Cargo Holds on board S.S. "Campania" and "Lucania." Transverse Section. The brine cooling pipes, which are of heavy 2-in. galvanised tube with malleable cast return bends, are placed on the ceiling between the deck beams, thus economising head room, and the rails for the meat- hooks are of 1^-in. galvanised round iron, firmly clipped to the beams supporting the decks. The meat hooks which are placed upon the latter, for carrying the quarters of beef, are of steel galvanised. Thermometer tubes from the upper deck are provided to each chamber, so that the temperature in any part of the chamber may be ascertained when desired. Fig. 296 is a plan showing the general arrangement of the machine- room. A pair of compressors are employed. A, A are the steam- engine cylinders; B, B the compression cylinders; c, c the ammonia condensers ; D, D the liquid ammonia reservoirs ; E, E, the refrigerators ; F is a brine circulating pump of the duplex pattern ; G is a manifold or distributing pipe to the different cooling pipes in the chambers ; H is the collecting pipe at the top of the refrigerator. It will be seen that the cold parts of the machine are enclosed in a separate chamber 410 REFRIGERATION AND COLD STORAGE. having walls insulated in a similar manner to those of the meat -carry ing stores or chambers, thereby preventing as far as practicable loss through absorption of heat. The compressors are of an ice-producing capacity of 12 tons a day, the compression cylinders being 6 in. in diameter by 12 in. stroke, and the steam cylinders 8 in. diameter by 12 in. stroke. The ammonia condensers c, which are more clearly shown in Fig. 296. Plan of Refrigerating Machine-room on Cunard Steamers. Figs. 293 and 294, are constructed of a cylindrical form, the shells being made of wrought iron, and the covers of cast iron, and they are fitted with concentric coils of IJ-in. galvanised iron pipe, connected together at their extremities by means of tee-pieces made of malleable castings. The ammonia condensers are in this case, moreover, carefully lagged with teak wood. The water for use in the ammonia condensers c is supplied and circulated by means of a duplex steam pump (not shown in the drawing), located in the forward boiler-room of the steamship. MARINE REFRIGERATION. 411 The ammonia gas after compression in the compressors B, and lique- faction in the condensers c, under the combined pressure of the pumps or compressors B, and the cooling action of the condensing water circulating on the exterior of the coils or worms in the condensers, is delivered to the reservoirs D for the liquefied ammonia, through small- bore pipes. From these reservoirs the liquid ammonia is admitted through suitable graduated expansion or regulating valves to the lower ends of the expansion coils in the refrigerators B, wherein the liquid ammonia again vaporises or gasifies, abstracting the heat required for this process from the brine surrounding the expansion coils, and being again returned to the compressors, and so on ad infinitum in the manner already described. The absolute working pressure in the refrigerators is about 30 Ibs. per square inch. The brine having been reduced to the desired temperature in the refrigerators, passes into the system of brine circulating pipes, and maintains the atmosphere of the cold stores or chambers at a tempera- ture suitable for the proper preservation of the meat. The circulation of the brine is effected by the brine pump F, which draws the cooled brine from the bottom of the refrigerators E, and discharges it through the distributing tee-piece and valves, or manifold G, to the different sections of the cooling pipes in the chambers, and returns it through a similar tee-piece, manifold or distributor H to the top of the refrigerator to be again cooled. The return brine pipes are each fitted with a regulating valve and a thermometer. The cold air or provision stores or chambers on board of the " Campania " and " Lucania " are fitted up with refrigerating plants, on the De La Vergne ammonia compression system. The refrigeration is effected on the brine circulation, and not upon the direct expansion system, a solution of calcium chloride being the agent or medium employed, and this solution is reduced to a very low temperature in the usual manner, by the expansion of the ammonia gas or vapour, in coils or pipes submerged therein, and is circulated by a special pump through the system of cooling or refrigerating pipes, which latter are fixed to the under side of the roof or ceiling of the cold store or chamber. The method employed for the insulation of the store or chamber is shown in Figs. 297 and 298, which are vertical sections through the roof or ceiling thereof. A, A are the refrigerating pipes ; B, B the meat rails ; c is a filling of sawdust ; D, D are layers or skins of tongued and grooved boarding; E is a layer of hair-felt; and F, F are layers of tarred waterproof paper. The brine pipes are divided 4i2 REFRIGERATION AND COLD STORAGE. into two sections or sets, thereby admitting of any necessary repairs being effected in one section, without in any way interfering with the circulation of the cold brine through the other section, and special means are also provided for withdrawing the brine from one set or section without interfering with the working of the other. The ammonia compressor is of the vertical single-acting type, and Fig. 297. Insulation of Provision Stores on board S.S. " Campania" and "Lucania." Transverse Section through Ceiling. is actuated by a high-pressure horizontal steam engine. The com- pressor cylinder is 4J in. in diameter, by 9 in. stroke, and the steam engine is of 2^ H.P., and is fitted with a special governing arrangement, by means of which the steam supply is determined, the speed being capable of variation within a wide range (say between 30 to 300 revolutions) without interfering with the running of the machine. Fig. 298. Insulation of Provision Stores on board S.S. " Campania" and "Lucania." Vertical Longitudinal Section through Ceiling. The construction of the compressor is substantially similar to that described with reference to Fig. 285, and the oil separator and other parts only differ from the arrangement shown in the general view of a complete installation shown in Fig. 19, in that the ammonia compressor is of the single-acting type, and by reason of the smaller capacity of the present plant, and the absolute necessity on shipboard for economising every cubic inch of room possible. The operation of the MARINE REFRIGERATION. 413 apparatus is, however, in every way identical, and the description of the complete installation will apply equally well in this case. The machine is capable of making 5 cwt. of ice daily, in addition to the performance of the refrigeration required in the cold storage or provision chamber. Fig. 299 shows an Enock electrically driven ammonia compression machine, marine pattern. In this arrangement, as shown in the illus- tration, the ammonia compression machine is coupled direct to the spindle Fig. 299. Enock Electrically-driven Ammonia Compression Machine, Marine Pattern. of a direct current slow speed motor mounted on an extended bed- plate. The compressor is of the double cylinder pattern, single acting, with from 20 to 30 Ibs. pressure of gas only upon the oil sealed packing, escape of gas being thus practically an impossibility, the joint being made on a revolving shaft instead of a reciprocating rod. The compressor is of the Enock safety self-oiling type, which will be found described in a previous chapter. As has been already mentioned, in spite of their inferior efficiency, 4H REFRIGERATION AND COLD STORAGE. n certain cases cold-air machines can be used to some advantage 5 on board men-of war for instance, which vessels remain at sea for some Fig. 300. Hall Vertical Marine Type of Steam-driven Cold-Air Machine. years, and a difficulty might be experienced in obtaining carbonic acid, or other volatile agent. MARINE REFRIGERATION. 415 Fig. 300 illustrates a Hall vertical marine type of steam-driven cold- air machine, fitted with compound steam cylinders, which is the pat- Fig. 301. Haslam Vertical Marine Type of Steam-driven Cold-Air Machine. tern ofj'machine supplied by Messrs J. & E. Hall, Ltd., to H.M. Admiralty, and to other navies. Another marine type of air compres- 416 REFRIGERATION AND COLD STORAGE. sion refrigerating machine, made by the above firm, is of a horizontal pattern, also fitted with compound steam cylinders. Figs. 301 and 302 show two recently designed marine types of Has- lam cold-air machines. That shown in Fig. 301 is from a photograph of one of two similar machines recently supplied to the Royal Fig. 302. Haslam Vertical Marine Type of Steam-driven Cold- Air Machine and Ice-making Apparatus. yacht. Fig. 302 is a pattern which has been supplied to the British Admiralty for the manufacture of 85 Ibs. of ice per day of twelve hours on warships. In a marine installation the pipe or trunk for admitting the cold air is usually fixed along one side of the cold store or chamber in the hold, as near the top or ceiling as possible, the return pipe or trunk MARINE REFRIGERATION. 417 being placed at the opposite side of the chamber. As in land installa- tion, the inlet trunk or pipe is fitted with a number of apertures governed by sliding doors ; these are only opened to a very slight extent at the end nearest the machine, and gradually more and more as they approach the end furthest therefrom, thus equalising the temperature in the chamber. The most important point is to ensure the cold air being thoroughly circulated and penetrating every portion of the chamber, and ther- mometers should be hung in different positions therein to form a check to the deck pipe ones. Where a cold-air machine, unprovided with a special arrangement for drying the air, is used, the snow box must be cleared out repeatedly, to prevent the passages, and also the slide valve ports, from becoming blocked up, and the trunk or inlet pipe must be cleaned once a day or oftener. For marine purposes the cold-air refrigerating machine was first in the field, and is still preferred before other systems by many engineers, and by the Admiralty ; but owing to certain defects in the earlier machines, other systems have been tried. The difficulty with any new system is the necessity for carrying a considerable store of chemicals, and serious accidents have resulted from the use of these machines on ship board.* There is also the danger of running short of these chemicals by any accident to the vessels in which they are stored. Now, with cold-air machines no chemicals are required, the pressures adopted are low, and possibility of accident to the machine is even more remote than accident to the main propelling engines. A new cold-air machine has recently been designed by Messrs T. & W. Cole, Ltd., to overcome the defects of the earlier machines of this type, in which each defect has been combated with marked success, as described in previous chapters. Previous to storing the carcasses in the cold storage place, a thorough inspection thereof should be made, and any damage to the walls made good. When the cold storage space in filled, the hatches should be made tight by caulking with oakum, or, preferably, they should be fitted with india-rubber insertions, which afford a greater certainty of air-tight joints being made. An arrangement of a small cold storage chamber, such as is very frequently constructed on board a large passenger steamer, is shown in sectional plan in Fig. 303. The refrigeration is effected by means of a Lightfoot, Ha'slam, or other cold-air machine of the vertical type. The arrangement of this cold storage chamber, which is practically * Vide leading article in The Engineer, 3rd January 1902. 27 418 REFRIGERATION AND COLD STORAGE. similar to that of those used on the passenger steamers of the Peninsular and Oriental Company, will be very readily understood from the drawing, wherein A is the meat room, the temperature of which is kept down to about 20 Fahr., and wherein are situated the ice-making or freezing tank B, the ice cans or cases B 1 B 1 , and the ice store c. D is the vegetable room, which is maintained at a temperature of about 40 Fahr., and in which are placed the water-cooler E, wine closet or cooler F, and hanging room G. It is, of course, obvious that the ice-making or congealing tanks or boxes, employed on shipboard, must be considerably modified in order t |> ' rmnr*-i-*- -,*> rrmvmtrv**-?* <, , r -r-+, , .,... ,1, ,+ ,. f ,.,..,,,,. ,-......, . . .?. . V . , .. \ ^ > '*/. I 001 i Fig. 303. Arrangement of Cold Storage Chamber on board Large Passenger Steamer. Sectional Plan. to provide for the motion of the vessel. In Fig. 304 is shown in plan, and in longitudinal and tranverse section, a type of marine ice-making box or tank designed by Mr Kilbourn, and installed by him on the International Navigation Company's vessels " St Louis " and " St Paul." In the left-hand top corner of the illustration is shown an end view of the refrigerating coils. Carcasses should be packed as close together as possible, consistent with safety, a space being left round the sides for the circulation of the cold air. The space allowed for the storage of a 56-lb. carcass in the refrigerated spaces on steamers is 2-8 cub. ft. The proper stowage of a fruit cargo in the cold store or chamber MARINE REFRIGERATION. 419 is likewise a matter that must be carefully attended to, in order to ensure its arrival at its destination in good condition. The essential point to be insisted upon is that clear spaces or clearances of at least J-in. be left between each tier of cases and between the cases and the bottom, sides, and ceiling of the chamber. These clearances can be managed by the insertion of laths of a suitable thickness between the cases. Passages should be also provided for admitting of inspections of the state of the fruit being made during the voyage. The best temperature to maintain for fruit is one of from 45 to 55 Fahr., and this should be evenly kept up throughout the entire cargo. It must be borne in mind that the slightest degree of frost Fig. 304. Ice-making or Congealing Tanks or Boxes for use on Shipboard. Plan, Side, and End Elevations, and Detail View will destroy a whole cargo of fruit. It will generally be found sufficient to run the refrigerating machine about twelve hours per day in hot latitudes and six hours per day in cooler ones. It is most important that the temperature should not be permitted to vary to any great extent during the voyage, and as considerable difficulty is experienced in attaining this end, it is desirable to provide a check upon those in charge. For this purpose a thermograph, or self- registering thermometer * is, or ought to be, provided in connection with each chamber fitted for the carriage of fruit, so that an accurate record may be kept of the actual changes of temperature that have * For description of thermograph or self -registering thermometer see pp. 574, 575. 420 REFRIGERATION AND COLD STORAGE. taken place during the voyage, and it can be seen at a glance on arrival whether the fruit has been carried under proper conditions or other- wise. Fig. 305 is a transverse section of a ship fitted with an arrange- ment of Sir A. Scale Haslam. Chambers as shown, are cooled by pipes, and are fitted with rails for hanging the meat in the ordinary manner. Channels are provided by which air can be supplied to the chambers through suitable openings, and also channels by which air can be drawn from the chambers through other openings. On the right is a Fig. 305. Haslam Method of Sterilising the Cold Air for use in Ships' Holds. fan for circulating the air through a chamber heated by steam pipes or by a jet of steam, or by both, and provided with a trap for removing condensed water. The air passing through this chamber is heated to, say, 300 Fahr. and may be treated to a steam injection, as it is well known by experiments that to effectually deal with bacterial growth and organisms it is necessary in many cases to moisten the air with steam at a high temperature, as well as to bring it in contact with hot surfaces at a high temperature. The heated and sterilised air is next passed into a tower where it is washed and cooled by a cold-water MARINE REFRIGERATION. 421 spray supplied by a pump, and from thence into another or cooling tower in which it is washed and further cooled by a spray of cold brine supplied by another pump. Baffle plates as shown are provided in the towers and also water and brine outlets. From the latter tower the cooled air passes to a drying chamber fitted with baffle plates and water or steam pipes, the latter being used if necessary to slightly raise the temperature of the air if it has been made too cold in the cooling tower. A water outlet is provided in this drying chamber. Essentially the operation consists in sterilising the air circulated through a chamber cooled by means of cold pipes or surfaces consisting in heating the air, then washing and cooling it, and lastly drying it by passing it over cold dry surfaces. BARGES. An important type of portable refrigerator is that adapted to meet the requirements of barges which it is desirable to maintain at a low temperature without encumbering them with machinery, or rendering in any way necessary the employment of special labour to take charge of the same. The frozen meat, as a. rule, arrives in good condition on board the vessels, and deterioration in quality usually takes place, as has been already mentioned, during its transference to the cold stores on land, and again during the subsequent delivery thereof to the retailer, when the meat is exposed to temperatures frequently much higher than what is required to preserve it in good condition. The Fulsome ter Engineer- ing Co., Ltd., claim to have devised a successful system of refrigeration for barges. Since the beginning of 1888, moreover, the London and Tilbury Lighterage Co., Ltd., have had barges fitted with special refrigerating apparatus successfully plying upon the Thames, the meat landed by them being invariably in good condition, and not infrequently at a lower temperature then than when first discharged from the vessel. CHAPTER XVII REFRIGERATION IN DAIEIES Methods of using Mechanical Refrigeration in Dairies Examples of Mechanical Refrigerating Installations in Dairies Milk or Cream Coolers Ice-cooled Creamery Refrigerators Air-Circulation System Cylinder System Insula- tion of Dairy or Creamery Refrigerators Size of Ice Chambers General Particulars Materials Ice Refrigerating Machine. THE term dairy, used in its widest sense, indicates a place where milk is preserved and prepared for sale or for family use, or converted into cream, butter, cheese, &c. The various applications of refrigeration in the dairy are summed up as follows by Mr Loudon Douglas in a paper read by him before the Cold Storage and Ice Association : (1) The cooling of town's milk. (2) The cooling of separated cream in an auxiliary creamery or separator station. (3) The cooling of separated and ripened cream in a main dairy or central creamery, as well as cooling water to wash butter whilst being worked, and cooling a butter store or cold room. (4) Regulating the temperature of cheese-ripening rooms and cooling rooms in which cheese is stored. (5) To the storing of eggs, &c. Butter is an unstable product. It is at its best when freshly made. Strictly speaking, deterioration begins at once, and it will become noticeable sooner or later according to the conditions under which the butter is kept. The most important condition in this respect is that of temperature, because no other condition has anything like the same influence in the preservation of butter. The preservation of butter means the checking to a greater or less extent of the processes of fermentation that affect the flavour, and which are inevitable in all butter, but it has never been found that even such extreme low tem- peratures will preserve the flavour indefinitely, although it has been proved beyond doubt that the lower the temperature the longer it will be preserved, other things being equal. Fortunately there is a certain period in the life of all good butter during which it may be considered to be at its best. Assuming that the butter has been well made, the REFRIGERATION IN DAIRIES. 423 duration of this period depends almost entirely on the temperature at which the butter is kept. Refrigeration is used in dairies, both for ensuring an ample supply of cold water and for cooling stores or chambers, the former being an essential for successful manufacture in hot weather, and the latter enabling butter to be kept in prime condition until a favourable oppor- tunity for disposing of it presents itself. Either mechanical or ice refrigeration is now employed in most dairies, mechanically produced cold, indeed, being acknowledged to be absolutely essential wherever a large quantity of milk has to be handled, whilst the small refrigerating machine, of comparatively recent introduction, can be advantageously employed in establishments with limited outputs, except in localities where natural ice can be stored at a figure as low as between two and three shillings per ton, and artificial cold be so economically pro- duced by this means as to render mechanical competition practically impossible. There are two methods of using mechanical refrigeration in a dairy direct cooling and accumulator cooling. In the first or the direct cooling method the machinery is capable of performing the required refrigerating work without the aid of brine storage, and is ready to cool milk directly after being started. This system necessitates a larger outlay at first, but is afterwards the most economical system to work. Tn the accu- mulator system a cold brine storage tank is provided, and the refri- gerating machine is started to cool a stock of brine some time before the milk is to be cooled. The result of this arrangement is that a small machine is capable of cooling some two or three times the quantity of milk. The total expenditure of power is greater than in the case of direct cooling, but the first cost is less. For accumulator cooling plants brine storage tanks should be made narrow and oblong so as to fit con- veniently against a wall, or round and high so as to occupy little floor space, or shallow to go on the top of the cold room. In all dairies where the milk is not despatched soon after being chilled, a cold room is required, which also serves for the purpose of keeping butter, cream, cheese, or other dairy produce. Fig. 306 illustrates a complete milk cooling plant, with warm milk tank and milk pump, built by A. G. Enock & Co. The machine is of the firm's ammonia (NH 3 ) self-contained type, in which the condenser coil is placed in the compressor jacket, and the gauges are mounted thereupon. Where a Pasteuriser is in use, it is arranged to deliver direct to the milk receiver. 424 REFRIGERATION AND COLD STORAGE. It is desirable that milk or cream can be rapidly chilled to between 40 and 50 Fahr., and modern competition renders it important that this operation should be performed at as small an expense as possible. s & if * The Enock double cooler, either of the flat, round, or conical type, with a water circulation from town or farm supply in the upper section, and a brine circulation from the refrigerating machine in the lower section, forms an efficient method of effecting the above cooling. New or REFRIGERATION IN DAIRIES. 425 Pasteurised milk can be reduced in temperature to 6O5 Fahr. with cooling water at 60 Fahr. In the lower section the brine circulation cools the milk down to 40 to 50, or lower if required. The plant shown in Fig. 306 operates as follows : The cold brine at 25 to 35 Fahr. is drawn by the brine pump from the brine cooling tank, delivered through the lower section of the milk cooler, and after chilling the milk, returns warm to the brine cooling tank, none being wasted. The brine cooling tank contains the evaporator coils in which the refrigerating medium evaporates, causing a very low temperature and absorbing the warmth from the brine. The refrigerating gas is drawn out of the coils by the compressor, which compresses and dis- charges into another coil placed in a tank of water forming the condenser. The warmth in the gas is " rendered sensible " by com- pression, and the condenser water carries off this "sensible heat," causing the gas to condense or liquefy. The liquid refrigerant then passes through an " expansion " or regulating valve into the refrigerator coils, where it again evaporates and cools the brine, the operation of evaporation, compression, and liquefaction being continuously repeated. In the arrangement (Fig. 307) an ammonia compression machine of the Kilbourn improved type, driven by means of belt gearing from a gas engine, is used. This cream cooler is fixed against the wall of the cold store or chamber, a portion of which latter only is shown in the drawing. The cream cooler is constructed of tinned copper, and is fitted with small wrought-iron coils without internal joints, similar coils being likewise provided in the water-cooling tank, a portion of which is shown on the top of the cold store or chamber. The refrigeration is effected on the direct system, the ammonia gas or vapour being permitted to expand into the coils of pipe in the cold store or chamber and of the cream and water coolers. An installation on the Hall carbonic anhydride (CO,,) system for cooling milk supplied to the Express Dairy Co., Ltd., London, is shown in Fig. 308. The plant consists of a single-acting compressor cut from a solid steel forging mounted on a vertical cast-iron base, the compressor being of the Hall standard type described on pages 132 to 138 with oil seal gland and pressure lubricator, and driven by a single-phase alternating current electric motor. The condenser is contained in an enclosed casing, so that the water after passing through it, can rise to an overhead storage tank. The evaporator coils are contained in a specially enlarged casing having a capacity of 400 gallons of brine. This enables the machine 426 REFRIGERATION AND COLD STORAGE. REFRIGERATION IN DAIRIES. 427 428 REFRIGERATION AND COLD STORAGE. to be run for about ten hours per day, so that the refrigerating effect is accumulated and stored in the cold brine which is rapidly circulated during the time that milk cooling is going on. The plant is arranged to deal with a total of 1,000 gallons of milk per day, cooling being carried out for one hour in the morning and one hour in the afternoon, 500 gallons being passed over the cooler at each time of cooling. The cooler is in one section, through which the brine is circulated from the refrigerating machine, and the milk in passing over it is cooled down to about 40. Fig. 309 shows an arrangement for cooling milk, constructed by HUMBOLDT Fig. 309. Installation for Milk Cooling on the Sulphurous Acid System. the British Humboldt Engineering Co., Ltd., London. The compressor is on the sulphurous acid (SO 2 ) system, and one of the company's vertical type of machine, and is connected with a milk cooler adapted for direct evaporation. A plant erected by the Swiss Co-operative Society at Geneva comprises two buildings one containing the machinery, the other the dairy and cheese factory. The supply of milk is obtained from societies of farmers in the vicinity of the city, who have depots to which the milk is delivered morning and evening, and where it is cooled to the temperature of the service water, and placed in hermeti- cally closed churns containing from 30 to 40 litres. The following REFRIGERATION IN DAIRIES. 429 particulars of the installation are given in "L'Industrie Frigorifique": The milk collected at the depots is delivered to the dairy in the city in the morning and evening. On its arrival the milk is weighed, filtered, and after being cooled by passing it through a Baudelot cooler (see Figs. 300 and 301) having a double circulation of service water and cold brine, is delivered into tanks, in which it is kept at a temperature of 3 C. The cooling of the cold room in which the milk is stored is effected by a circulation of cold brine through pipes having radiating gills, and it is maintained at - 6 C. The milk which arrives in the morning remains in the cold room until the evening; that which is received in the evening is delivered on the morning following. The distribution is made in square churns with rounded corners, having each a capacity of from 40 to 45 litres, and four of these churns are placed in each hand-cart. Each churn has a draw-off cock opened by a special key, and to prevent, as far as possible, agitation of the milk during its withdrawal it is delivered through a tube to the bottom of the cans, and these are thus filled from the bottom upwards. Provision is made on the hand-carts for ice cooling during the summer. Any milk not sold on the rounds is returned to the dairy, where it is made into butter and cheese. The skim milk resulting from butter making is made into cheese. The dairy has a sale for from 15,000 to 20,000 litres of milk a day. The power required is from 30 to 40 H.P., and steam is also required for cleansing purposes. The refrigeration is produced by a sulphurous acid (SO 2 ) compression machine of a capacity of 25,000 frigories) about 99,200 B.Th.IL), the brine being maintained at a temperature of -2 to -5, and the tank having very large dimensions so as to form an accumulator. The condensing water is cooled by means of an open-air evaporative surface condenser situated on the roof of the building. It was formerly held that the freezing of butter by causing a rupture of the fat globules produced a deterioration in the quality of the butter after thawing, but this idea has been now abandoned, and was never borne out by the practical experience of butter merchants. In fact, for the storage of butter for any lengthened period of time in hot climates, or for a transport by rail over long distances, freezing is usually advisable, as it has been found that butter so treated is far superior to that which has been chilled or kept in ordinary cold storage. Frozen butter both retains its flavour and body better than the other, and what is of considerable importance, is less easily affected by bad odours or other contamination. This result, 430 REFRIGERATION AND COLD STORAGE. Cream Cooler and Heater. Plan. however, depends to a great extent upon the care that has been bestowed upon making the butter, viz., whether it has been washed quite clean, to what extent it has been worked in the butter -worker, and to the precautions that have been taken in packing whilst in a chilled condition. See also pages 437 and 438, and ante, pages 385 and 386. Tt may here be impressed on those concerned in the storage of butter that the greatest precautions should be taken to protect that commodity from contact with the gases due to decomposition, , or with the minute particles that may Fig. 310. Sandbach Combined , . , . , r . . , _J be contained in the air of the cold- storage room or chamber, and which the butter will absorb very freely. An ordinary form of milk or cream cooler consists simply in a pan fitted with a false bottom, through the space or clearance between which and the real bottom a circulation of cold or j . refrigerated water is maintained. The ftfli I coolers in most general use are either of a cylindrical form, such as the Danish circular coolers, or they have flat cor- rugated sides; both types are fitted with top and bottom troughs. Figs. 310 and 311 show in plan and elevation the Sandbach combined cream cooler and heater, which is said to be a very good system for the rapid ref rigera tion of cream. The apparatus consists essentially of the following parts : A ripening vat and combined cooler and heater, and a mechanical agitator driven off the main shafting. The cooling or heating apparatus is so designed that it pre- sents a large cooling or heating surface in a comparatively small space, and when employed in the former purpose can be used in conjunction with any description of refrigerating machine, either for cooling cream or for the production of iced water. Fig. 311. Sandbach Combined Cream Cooler and Heater. Ele- vation. REFRIGERATION IN DAIRIES. OUTfcET Fig. 312 is a circular capillary cream cooler. This type of cooler, which is much used in Belgian dairies and creameries, is made in various sizes, the largest having a cooling capacity of about 200 gallons per hour from 65 to 52 Fahr. It can be used with any refrigerating machine, and the cold brine is pumped through the cooler, the cream passing over the exterior. In all large dairies the Pasteurisation of milk is now become part of the ordinary routine, and this process creates a demand for additional refrigerating machinery, it being absolutely essential to reduce the temperature after Pasteurisation as rapidly as it can possibly be effected. Cream coolers of the submerged type are said to reduce trouble of cleansing to a minimum. A bulletin entitled "Creamery Cold Storage," written by Mr J. A. Ruddick, the Dairy Commissioner, Canadian Department of Agriculture, goes very fully into the sub- ject of ice cooling and contains much valuable information. The following particulars are abstracted from this source. For small or medium-sized creameries the first cost of installation and the annual ex- pense of operation put the mechanical system out of the question. The following are ex- amples of creamery refrigerators designed by Mr Ruddick, adapted to be cooled by ice, but it will be understood that the buildings with certain simple modifications would be suitable for the installation of machinery for mechanical refrigeration. Although it may be possible to secure rather lower temperatures with the cylinder system than can be obtained with the air-circulation system, all things considered, a lower average temperature is usually found where the air-circulation system is in use. Both the ice chamber and the cold-storage room are thoroughly insulated. Figs. 313 and 314 show plan]]and section of a creamery refrigerator on the air-circulation system. It will be seen that there is a connection between the two rooms which provides for the circulation of air over the ice and through the cold-storage chamber. The working of such a refrigerator is automatic, and requires only to Fig. 312. Capillary Cream Cooler. Elevation. 432 REFRIGERATION AND COLD STORAGE. be regulated by the opening and closing of the slides that control the circulation of air. The ice is not covered as the thorough insulation of the walls of the ice chamber is depended on to prevent undue waste. i i *^ 8 S, "I > \ ffCftf/eefATOff Jf- 3 f = - a $ \ Be - ii it vf ? I I , Of 1 IM c^ r V? n y* J/ "r i -iL ^ fli Ssi 1 i^n nrna 3Oi jo 77 H s i D T n ' n 19 ""*^" . * a; : " S 5.,4 S tei^ * . I fH 1 In this system galvanised-iron cylinders about 1 ft. in diameter are placed in the cold storage room so as to extend from the floor to the ceiling and opening into the room or loft above. A row of these cylinders should extend along at least one-fourth of the wall REFRIGERATION IN DAIRIES. 433 space of the storage room. The cylinders are filled from above with crushed ice and salt, the proportion of which may be varied according to the temperature desired. The larger the proportion of salt the better the results will be, until the maximum is reached at about 1 part of salt to 3 of ice. Drainage must be provided to carry off the water from the melting ice, and the outlet should always be trapped in order to prevent the passage of air. The ice for this system is usually stored in an ordinary ice shed, covered with sawdust, cut hay, or other insulating material. The cylinders must be kept full in order to secure the maximum of refrigeration. The labour of breaking the ice and filling the cylinders is very considerable and constitutes one of the chief objections to the cylinder system. Where the refrigeration depends upon the daily performance, by the butter- maker, of this item of labour, it is very apt to be more or less neglected. If the cylinders are allowed to become partially empty, there is a corresponding rise of temperature in the storage room, and this is what very often occurs. The cylinder system is the cheapest to instal, because the storage room only need be insulated, but the large amount of labour involved in keeping the cylinders properly filled, and the cost of the salt, make the operation of this system somewhat expensive. Where there is plenty of cheap labour and someone to take sufficient interest in the question to see that the work is properly attended to, there is no doubt but this system will give good results, as far as ice goes, for the storage of butter. Fig. 315 shows plan and section, and Fig. 316 details, of a creamery refrigerator on the cylinder system. In the construction of insulated walls, the best practice at the present time provides for an outer and an inner shell, as nearly as practicable impervious to air and dampness, with a space between to be filled with some non-conducting material. The width of the space will depend on the filling to be used and the temperature to be maintained in the storage room. For a creamery cold storage constructed of wood there is no better material for filling spaces than planing-mill shavings. The weight of shavings required to fill a given space will depend somewhat on the- kind of wood from which they are made, and also to some extent on how tightly they are packed, but a fair average is from 7 to 9 Ibs. per cubic foot of space. They should be packed sufficiently to prevent future settling. See also chapter on Insulation, pages 329 to 365. All inside sheathing should be of spruce, because of its non- odourless character. The inside surface of ante-rooms and cold storage 28 434 REFRIGERATION AND COLD STORAGE. rooms should receive a coat of shellac or hard oil. This will permit of the walls being thoroughly washed and disinfected to destroy spores of mould. Whitewash is also used as an interior finish. It is cheap and can be renewed from time to time. A little salt mixed with whitewash is said to harden it, and thus prevent it from rubbing off when touched. If the inside sheathing of the ice chamber is coated with paraffin SECTION. ^ <^" .*. PLAN. Fig. 315. Plan and Section. OCTAIL or WALL s. Fig. 316. Detail Views. Creamery Refrigerator on the Cylinder System. wax, like a butter box, the lumber will be preserved and moisture prevented from getting into the insulation. It is impossible to lay down any rule as to the total quantity of ice required for creameries with a given output, as so much depends on what the ice is used for, and also on the nature of the water supply. In many creameries, where there is an ample supply of cold water, no ice is used for cream cooling, while for others a large quantity is pro- vided for that purpose. If a Pasteuriser is used, the extra cooling REFRIGERATION IN DAIRIES. 435 required increases the consumption of ice very considerably. It is important, however, to estimate correctly the size of the ice chamber required for a cold storage on the circulation system. Where this system is used the supply of ice for cream cooling purposes should be kept separate from the cold storage supply. The ice chamber should not be opened during the summer except for occasional examination. The quantities given in the following table will be found to be about right for average circumstances : Pounds of Butter made during Summer Months. Tons of Ice required for Sutler Storage only. Size of Ice Chamber in Cubic Feet. 200,000 100,000 50,000 140 80 50 5,000 3,000 2,000 Where ice is required for cream-cooling purposes, and it generally is, about one-half the quantity given in the table will be required in addition. This can be stored in an ordinary ice shed and covered with sawdust. Creamery refrigerators on the air-circulation and on the cylinder systems consist of (1) An insulated ice chamber, where the ice is kept without any covering. (2) A cold storage room, where the packages of butter for export only shall be stored. (3) An ante-room, to receive retail butter and to protect the storage room against the entrance of warm air. Both cold storage room and ante-room are cooled by the circulation of the air which passes over the ice in the ice chamber. The situation should be at the north end of the creamery, or sheltered from the direct rays of the sun if possible. The size will be determined by the output of the creamery. Butter should be shipped every week wherever possible, and in this case the cold storage room should not be much larger than necessary to hold a week's make, with convenience for handling the packages. A room 7 ft. high by 8 ft. sq. inside will hold conveniently 120 boxes, piled six high. The ante-room should be large enough so that the door can be conveniently closed before opening the door of the cold storage room. As regards light, it is not desirable to have a window in the cold storage room. Sufficient light can be had from a lamp or candle when necessary. A window may be put in the ante-room. Good insulation should be provided on all sides of the refrigerator 436 REFRIGERATION AND COLD STORAGE. around cold storage room ; and ante-room, whether adjoining the ice chamber or any other part of the creamery, must be equally well insulated. Wood. All lumber employed must be thoroughly dry and sound without loose knots or shakes, and must be odourless. Spruce and hemlock are the best in the order named. Pine is not suitable for inside sheathing, on account of its odour. All boards employed should be dressed as well as tongued and grooved. Unseasoned lumber must be carefully avoided. When building in winter, fires must be kept going so as to have all materials as dry as possible. This is very important, as dampness in insulation destroys its effi- ciency. Paper. All papers used should be strictly odourless and damp-proof. Tar paper, felt paper, straw paper, rosin- sized paper, and all other common building papers are not suitable and must not be used. Use double thick- ness of paper in all cases, each layer lapping 2 in. over preceding one. The layers should extend continuously around all corners. All breaks to be carefully covered. Shavinys. Shavings must be thoroughly dry, free from bark or other dirt. Shavings from some odourless wood, such as hemlock, spruce, or white wood, to have the preference. The Burnand ice refrigerating machine, two types of which are shown in Figs. 317 and 318, is especially designed for use in small dairies where ice refrigeration is used. The essential features of the apparatus, shown in Fig. 317, consists in a stout oak tub joining an insulated receptacle and fitted with one or more copper- coils according to the capacity required. The space round the copper coil or coils is filled with a freezing mixture, such as finely broken ice and salt, and the temperature of the brine or Fig. 317. Burnand Ice Refrigerating Machine for Dairies. REFRIGERATION IN DAIRIES. 437 water pumped through the coil or coils is thus reduced to the required degree. The brine or water enters the inner coil at the bottom, and from the top is conveyed to an inlet at the bottom of the outer coil. Also, leaving this latter coil at the top, it may be con- veyed either to the refrigerating pipes in a cold store, to an ordinary pattern milk cooler, or to other cooling apparatus, and after performing the duty required, returned to a reservoir in order to be again circulated through the refrigerator. To equalise the temperature of the liquefied freezing medium, an agitator, as shown in the drawing, is provided. In this apparatus the circulation of the brine or water through the cooling coils is effected by means of a power-driven pump not shown, and the agitator paddles are driven through the bevel gearing and belt pulley from any convenient source of power. The small milk cooling apparatus shown in Fig. 318 is intended to be worked by hand power. On the top is a reservoir for the milk to be cooled, which communicates through a stop- cock with a capillary cooler. The cool- ing liquid is pumped by means of the semi-rotary hand pump shown from the well in the bottom of the tub to the cooler, and after passing through this latter, it is sprayed on the upper part of the broken ice in the tub, and returns to the cold well to be again passed to the cooler, and so on, until the supply of broken ice in the tub is exhausted. Dr Samuel Rideal says that very great caution has to be exercised regarding the various temperatures required for different classes of dairy produce as well as care in the methods of preparation and storage prior to refrigeration. The cold storage of milk and butter has been already dealt with in this chapter, and also to some extent in Chapter XV. under the heading of "Proper Methods for Storing and Temperatures for the Cold Storage of Various Articles." In conclusion it may be observed that in the United States there are a considerable number of persons who advocate the storing of butter at a temperature of Fahr., claiming that butter is un- desirably affected by a rise in temperature above that point. On this particular question considerable diversity of opinion seems to Fig. 318. Burnand Small Ice Milk Cooling Apparatus. 433 REFRIGERATION AND COLD STORAGE. exist. Mr Arthur G. Enock, M.I.M.E., who has had a very extensive experience in the subject of dairy refrigeration, in reply to a query put to him some time ago by the author as to the proper cold storage temperature for butter, said that from his own experience he thought that there can be no hard and fast rule for butter as such, because various butters require different treatments, and again different tem- peratures, according to the treatment they have received since being made. His experience of fresh Colonial butter, made in Australia, with chilled water by chilled cream from Pasteurised milk, is that the lowest temperature necessary to keep it in first-rate condition for an indefinite period, as far as practical commerce is required, is 20. But if you get that butter made with all care, and then carried about for a week or ten days without being placed in a cold store, you may want to bring it down to 15 to hold it successfully. Very much the same applies to Irish butter. With all the conditions of manufacture and storage one meets with between Ireland and this country, it is Mr Enock's opinion and experience that 24 is the right temperature, provided the atmosphere is kept fairly dry. The employment of such a degree as Fahr., or even 14, is something which, as far as Mr Enock's experience has gone, is unneces- sary under ordinary conditions, although possibly special conditions might arise, for example, when butter has to be transmitted by rail for some distance. In the South African cold stores at the ports butter used to be carried down to 10, and even to 5, but this was in preparation for transit for three or four days by ordinary railway waggon, slightly insulated, through a very warm country. Such a condition as this, however, does not apply where butter is simply held in storage for in and out use. As regards the question as to whether butter taken from the dairy, and put into a storage somewhat below freezing, would be found to maintain its quality. Mr Enock thinks that it would be found to do so, but that, at the same time, a good deal depends on how the butter is made. Whether it is washed quite clean, how much it is worked in the butter-worker, and what care is taken in packing it while it is in a chilled condition. For use of refrigeration in artificial butter factories see pages 461 to 464. CHAPTER XVIII MANUFACTURING, INDUSTRIAL, AND CONSTRUC- TIONAL APPLICATIONS Chocolate Manufacture Breweries Paraffin Works Artificial Butter Manufac- tories Tea Factories Sugar Factories and Refineries Blast Furnaces Wine-MakingVarious other Manufacturing and Industrial Applications Dynamite Factories Manufactories of Photographic Accessories Dis- tilleries Chemical Works India-rubber Works Glue Works Construc- tional Applications Tunnelling, Sinking Shafts, Laying Foundations, &c. INDUSTRIAL AND MANUFACTURING APPLICATIONS. USES are now made of refrigeration in many manufactures and indus- tries besides that of its more legitimate and important application to the preservation of various provisions of a perishable nature, which latter has been already dealt with so far as space would allow in pre- ceding chapters. All the systems hereinbefore described, with the exceptions of the first, or that wherein the abstraction of heat is effected by the more or less rapid dissolution or liquefaction of a solid, are, to a greater or a less degree, advantageously applicable for this purpose. Although the preservation of organic substances was the first known and the most obvious use, the successful application of artificial refri- geration to a process of manufacture is somewhat older than that to the preservation of provisions, a Harrison ether machine having been erected at Truman, Hanbury, & Co.'s brewery about 1856, which machine was stated, at a meeting of the Institution of Mechanical Engineers held in 1886,* to be still at work and acting efficiently. A machine of the same type was also said to have been put up by A. C. Kirk in 1861,f who employed it for the extraction of solid paraffin from shale oil. Another important application of refrigerating machinery is to constructional work, such as the formation of tunnels, the sinking of * Proceedings, Institution of Mechanical Engineers, 1886, p. 246. t Ibid., p. 231. 439 440 REFRIGERATION AND COLD STORAGE. shafts, wells, laying of foundations, &c., in loose ground, in quicksand soils, or wherever the amount of water is too great to be pumped or the doing so would be dangerous or inconvenient. REFRIGERATION IN CHOCOLATE MANUFACTORIES. The application of a refrigerating machine to the cooling of choco- late during the process of manufacture was first made by J. S. Fry in 1882,* in which year he employed one of Lightfoot's double-expansion horizontal cold-air machines, and was enabled to proceed without interruption throughout the whole year with work that had previously to be suspended during the hot weather. Since that time the use of refrigerating machines in chocolate works has become almost universal. A great saving in chocolate manufacture is likewise effected by the rapid solidification which is rendered possible, and the waste thus avoided ; and furthermore, as the chocolate leaves the moulds readily and intact, a considerably fewer number of the latter are required to do the same amount of work. The essential features to be kept in view in designing and con- structing a chocolate cooler may be enumerated as follows : Uniform cooling of all the goods put into the apparatus ; reduction of labour- in feeding and taking out the trays containing the chocolate to a minimum; economy of cold air and reduction of the required refrigerating power; and, lastly, simplification of the construction to keep the outlay as low as possible, consistently with obtaining the best results. The patent chocolate cooler shown in our illustrations Figs. 31 9 and 320 is made by Messrs A. G. Enock & Co., Ltd., and is claimed by the inventors to embody the above qualities as far as practicable. The cooler consists of an insulated box containing a shaft with a six- sided frame at each end. The two frames are connected by bars upon which the chocolate carriers hang. The shaft is rotated by the hand-wheel outside the cooler and an automatic stop arrests the shaft when the trays come opposite the inlet and outlet slots. It will be seen that each tray of chocolate makes a complete circuit of the cooler, descending from the warmer air at the top, passing through the colder air at the bottom and returning to the top. This method is claimed to be better than revolving the trays horizontally as it will ensure that each tray gets the same amount of cooling. The trays are fed into the slots shown at the right-hand side of the * Proceedings, Institution of Mechanical Engineers, 1886, p. 236. MANUFACTURING APPLICATIONS. 441 442 REFRIGERATION AND COLD STORAGE. cross section, Fig. 320, the cooler shown in the illustration accommodat- ing twelve trays, each measuring 30 by 21 in., and after each carrier has received its two trays the hand-wheel is revolved and the next carrier filled, and so on until all the trays are in place. When the first carrier returns to the top after having made a complete circuit, two fresh trays are put in and the action of putting them in pushes out the other two trays at the left-hand end of the cooler. The work may thus go on continually. And as the cold air naturally falls to the bottom of the cooler, and as the trays are both fed into and discharged from the cooler at the top, there is no loss of cold air. In the pattern of cooler shown in the illustrations flaps are provided for closing the openings through which the trays pass in and out, but in another arrangement these apertures are automatically closed by narrow spring shutters which rise into place after a tray has been put in or pushed out of the carriers. The insulation consists of 6 in. thick of best silicate cotton or other approved material, the walls of the cooler being lined with white enamelled material ensuring perfect cleanliness and absence of odours. The cooler box is made up in sections, and can be bolted together and set at work by any ordinary carpenter or mechanic. The smaller sizes, however, can be sent out complete in one piece. The cooler is complete with coils of direct expansion or brine circulating pipes, with counter flanges ready to connect to new or existing refrigerating machinery. The cooler is capable of accom- modating trays of any width from 12 to 22 in., which is advantageous, inasmuch as the trays employed by different makers vary considerably in size. The capacities of the machines vary from 1 ton per day of chocolate cooled for the smallest up to 3 tons for the largest-sized machine. The cold-air machine is well adapted for chocolate cooling, pro- vided only that the air be dry, an achievement claimed by the inventors for the " Arctic " machine, and Messrs Cole have applied it to several chocolate factories with complete success. An advantage of this system is that whilst some forms of refrigerating machines only very partially dry the air, and that inside the room, by deposition of frost on brine pipes, or producing a current of air over brine- wetted surfaces, the "Arctic" cold-air machine acts upon the air before delivering it to the cold-room, or other apparatus, and thus the moisture is deposited outside of and away from the cold-room. There is also the further advantage of there being no brine pipes on which to deposit frost, which may drop on to the chocolate trays, &c., and MANUFACTURING APPLICATIONS. 443 requires the provision of special draining gutters, all of which apparati are frequently more or less imperfect in their action. A rotary chocolate cooler devised by Mr J. C. Broadbent and Mr J. McRae is claimed to preserve the chocolate from any moisture during the process of becoming solid. This apparatus consists of a series of chambers revolving on a central pivot. The cooler is cylindrical, with a diameter of about 10 ft. and a height of 8 ft. The outside, that is, the case, is constructed of wood, and insulation is secured by the use of silicate cotton. The circular basis of the apparatus is, of course, furnished with a like insulating substance. The upright steel axle is 2J in. in diameter, and round this revolve the sets of shelves. Every set of shelves is fitted with wooden sides, so that these form in the outer shell six perfectly isolated and refrigerating compartments, the whole being furnished with a toothed revolving gear connected by a hand-wheel situated at the front of the machine. The chambers are provided with an arrangement of spaces for cooling by brine. These have to be put in position when the cooler is to be used, so that none of their number can coincide with the door space of the cooler itself. The shelves of each compartment in the cooler run 2 ft. 9 in. long by 1 ft. 9 in. wide. Of these compartments there are six, with a space of 5 in. between each. The special trays on each shelf are adjusted to carry from 10 to 15 Ibs., but where it is required, by a simple change, blocks of any size can be cooled. The ordinary capacity of an apparatus of the above dimensions is 30 cwt. a day, but a much greater capacity can be had when desired. One of the advantages claimed for this apparatus is that no fastenings are needed. It is constructed on the wedge principle, and hence all the doors close automatically tight. The apparatus is so arranged that when the compartments revolve, and one of them arrives at the door space, and the door is opened, elliptical shutters are automatically operated and cause the sides of the compartment to fit so perfectly that the rest of the cooler remains completely isolated from the air. In point of fact the door may be left open at any time without there being the slightest change in the temperature of any of the other compartments. Then again the top and bottom shutters of each division are absolutely self-acting automatic, in fact and thus render the compartment entirely air-tight. Another feature is that the upper and lower ends of the several compartments are so made that, as the shelves rotate, the upper and lower divisions open on the parallel lever system, and directly rotation ceases they shut. A Steinle's thermometer keeps a record of the temperature inside the 444 REFRIGERATION AND COLD STORAGE. cooler and is read on the outside. There is also an ingenious plan by which the contents of the cooler are indicated. The circular top is graduated by six marks numbered from one to six, corresponding to the six compartments. In order to charge and uncharge, the wheel beside the door of the cooler is simply turned until the required number coincides with a fixed pointer in the front. A convenient arrangement is provided for marking the time at which the different compartments are charged, and a timepiece is fixed in the middle of a plate having six dials furnished with movable hands. To facilitate occasional cleaning, the top of the cooler is equipped with a vapour valve, through which an air current can be passed for that purpose. In another apparatus for treating chocolate an endless travelling band or apron is provided by means of which the chocolate is traversed through a refrigerated compartment. REFRIGERATION IN BREWERIES. One of the, if not the most, important of the industrial applications of refrigerating machines is that of cooling water to be used for refrigerating and attemperating purposes in breweries. This is more especially required when the supply of water is derived from a river or other source exposed to the heat of the sun, or from the water mains in large towns, the water from both of these sources usually rising during the summer months to from 65 to 70 Fahr. Where a plentiful supply of well water at a temperature of from 50 to 54 Fahr. can be obtained, the provision of means for artificial cooling becomes of minor importance for this special purpose, and can be dispensed with. When, however, the water supply is at a comparatively high tem- perature, such as that above indicated, it would of course be totally impossible to cool the worts down to the ordinary pitching tempera- tures of from 57 to 59 Fahr., or to control the fermentation in the tuns or squares with water at such a temperature passing through the attemperators, and, moreover, on the completion of the fermentations it would be likewise quite impracticable to cool the finished beers down to the temperature desirable for racking. One of the first operations is the refrigerating of the hot beer wort. The usual practice is to first slightly reduce the temperature of the hot wort by exposing it in the large tank known as the cool-bed or cool-ship, which is generally located on the top of a building and roofed over, the sides being only enclosed by lattice-work, so as to MANUFACTURING APPLICATIONS. 445 allow a free circulation of air, and then permit it to flow slowly down over the tubes or coils of a " Baudelot cooler." The Pontifex-Wood brine refrigerator is also successfully employed for cooling beer worts. This apparatus consists essentially of sets or rows of copper or brass tubes arranged horizontally, and secured at their extremities in return heads. Through these tubes and heads the cold brine from the refrigerator is caused to flow, and the beer worts to be cooled are allowed to trickle over their exterior surfaces. An ordinary refrigerator for cooling hot beer wort consists of a shallow vat wherein is mounted a continuous tube or pipe, through which the cooling water is forced in a direction opposite to that taken by the wort. The object of thus running the wort in one direction and the water in another is to ensure the delivery end of the wort being exposed to the coldest portion of the stream of water. In another form the wort passes through a coil of pipe arranged in a vat, through which a circulation of cooling water is kept up. A more complicated arrange- ment is that wherein boxes are arranged to project alternately from opposite sides of a double-walled vertical case ; through the latter, and which boxes, the wort is caused to take a zigzag course by suitable check-plates extending centrally into the boxes. The cooling water takes a like sinuous or zigzag course on the exterior of these boxes. A wort or beer-cooler, employed in many large breweries, is a large shallow, covered vat, fitted with a volute formed by a wide strip of metal set on edge between the upper and lower plates or heads, to which it is attached in such a manner as to form a helix with two distinct spaces. Through one of these spaces the refrigerating liquid, or medium, is circulated, suitable inlet and outlet passages being provided, and through the other the wort or beer to be cooled. Brotherhood's refrigerator consists of a number of long boxes placed side by side or otherwise, each box having a flow and return passage for the cooling water, and copper tubes through which the wort passes. Hollow covers at the ends of the boxes afford communication between one tier of tubes and another. Mash tuns are likewise constructed in which the vertical shaft carrying the rake or stirrer is formed hollow, as also the arms of the side rake, which latter are perforated with a number of small holes. Through the above-mentioned hollow shaft and perforated arm steam is first passed to boil the wort, and subsequently air, reduced to a low temperature in order to cool or refrigerate it. In a refrigerating or cooling apparatus on a somewhat similar principle, air, previously reduced to a low temperature, is forced into the perforated false 446 REFRIGERATION AND COLD STORAGE. bottom of a vat, from whence it escapes through these holes or perforations and passes up through the wort or beer contained therein. Numerous other arrangements are also in use in this country and abroad. One of which, of American origin, is as follows : First the hot wort is delivered into a trough of V shape in transverse section, from the bottom of which it trickles over a series of horizontal pipes arranged in line vertically, and through which the cooling water is passed, the cooled wort being finally collected in a U-shaped trough for delivery to the fermenting tun. An apparatus which is extensively used in America for cooling or refrigerating hot beer wort, is that known as the " Baudelot cooler." Fig. 321. "Baudelot Cooler," with Direct Expansion for Cooling Hot Beer Wort. This apparatus is constructed for use both with a brine circulation and direct expansion. In the first arrangement, shown in Fig. 321, the upper portion, or half of a set of tubes or coils arranged horizontally, is cooled by the ordinary well or main water, and the lower part or half thereof by mechanical refrigeration on the direct-expansion system. In the second arrangement, shown in Fig. 322, the upper part or half of the pipes or coils is similarly cooled, but the lower portion or half is cooled by brine circulation. The above Baudelot cooling apparatus is made by the Frick Co., U.S. Another, and also a very important, use for a refrigerating machine in breweries is that of cooling the air in the fermenting and yeast rooms, an arrangement for which purpose on the brine-circulation MANUFACTURING APPLICATIONS. 447 systems is shown in Fig. 323. This cooling is necessary during hot weather, even in cases where an unlimited supply of cold water for refrigerating and attemperating is obtainable, inasmuch as the water can only be applied to the cooling of the beer itself in the fermenting vessels, and not to the head of yeast above. The result of this is that, although the fermenting beers can be well kept under control by the use of the attemperators, the yeast above is frequently found to be going wrong by reason of the excessive temperature of the atmosphere of the room. UPPER PORTION OP BAUDELOT COOLED BY WE"tU OR HYDRANT WATER Fig. 322. "Baudelot Cooler," with Brine Circulation for Cooling Beer Wort. In employing a refrigerating machine for this purpose, brine reduced in the cooler or refrigerator to about the temperature of the latter, that is from 10 to 20 Fahr., or very much lower if desired, is circulated through rows of pipes B, fixed over the tuns A, or the squares, to be cooled in the fermenting rooms, and also in the yeast rooms, the system of pipes being reduced by the brine to below freezing-point, and the atmosphere of the rooms from contact with the latter to 45 or 50 Fahr., or any other desired point. By this means an October temperature, that is to say, one of 50 Fahr. or less, can be obtained during the hottest summer weather. 448 REFRIGERATION AND COLD STORAGE. Fig. 324 shows an arrangement for cooling a fermenting room on the direct expansion principle, fitted with the De La Vergne patented pipe system, a detailed description of which will be found in a previous chapter. The speed of the flow of brine in the first arrangement, shown in Fig. 323 through the various circulations, can be regulated at will by means of stop-cocks or valves provided on the several branch mains, and that of the gas or vapour in the second arrangement, shown in Fig. 324, by the expansion valve, and consequently, the temperature of the fermenting rooms can be regulated at will. In simple arrange- Fig. 323. Arrangement for Cooling Fermenting and Yeast Rooms in Brewery on the Brine Circulation System. ments, such as the foregoing, the brine mains B and the direct expansion pipes respectively, cool the entire area of the fermenting room, that is to say, a separate brine circulation (Fig. 323) or coil of vapour pipes (Fig. 324) is run over each row of rounds or tuns, and all are cooled at once. Where a number of large squares have to be cooled, however, a more elaborate arrangement is preferably employed, and the sides and tops of the squares are boxed in or enclosed with partitions formed of light boarding, under which a separate circulation of brine or vapour pipes to each square is fixed. The latter plan enables the temperature of the air over each square MANUFACTURING APPLICATIONS. 449 to be regulated separately and independently of the others, and the brine or vapour to be shut off completely from empty squares, thereby lessening the work of the refrigerating machine. It also further economises the work of the latter, inasmuch as only the air directly over each vessel has to be cooled. In working a refrigerating machine on the brine circulation principle, for these cooling purposes, in a brewery of moderate dimensions, it is usually run during the daytime, and when it is shut off at night, and the fermenting rooms are closed up, the large amount of cold stored up in the brine in the pipes over the fermenting Fig. 324. Arrangement for Cooling Fermenting Room on Direct Expansion Principle on the De La Vergne System. vessels, is, as a rule, found to be sufficient to keep the atmosphere of the rooms down to the desired temperature during the night ; except, however, in very hot weather, when the machine has usually to be run continuously. In very large breweries also it has generally to be kept working day and night. In some instances, a refrigerating machine is employed for the combined purposes of cooling water for use in refrigerating and attem- perating and of cooling the air in the fermenting and yeast rooms. In an arrangement of this description, at the top of the brewery building, or at a sufficient elevation to command the refrigerators and 29 450 REFRIGERATION AND COLD STORAGE. attemporators, is fixed a suitable ice-water tank, and above this tank a brine refrigerator, which latter may consist of horizontal rows of brass or copper pipes, through which a branch circulation of cold brine from the mains is run, whilst over them the supply water at 60 or 65 Fahr. or other temperature is allowed to trickle or flow slowly. This water is thus reduced by the cold brine within the pipes to about 33 Fahr., or to any other desired temperature, after which it is passed into the ice or cold-water tank, from which it is drawn through pipes as required for refrigerating and attemperating. This arrange- ment admits, by the simple opening, closing, or regulating of the \\\N> \v\\\\\\\\\\\\>- \\\\\ Y v\ v\\\ VXA.X \ \ \ \\v\\\\\v^ 5000 c I C t C 1 t I C J ' <5$6Qs& \ aoooc 10. Q Q_ O O Q Q O O OOP OOP >OQQ t >OOQC yooooq 3QOOQQ Fig. 325. Frick Company's Method of Cooling a Fermenting Room in Brewery. stop-cocks or valves, of the whole or any desired proportion of the power of the machine being applied to the cooling of air, or to the cooling of water, or to both operations at the same time. Lager beer fermenting rooms and store cellars can be cooled by a plan substantially similar to that shown in Fig. 323, for cooling the air in fermenting and yeast rooms in ordinary breweries. In the case of lager beer, however, where the whole of the fermenting rooms are kept at a temperature of about 42 Fahr. and the stores at about 38 Fahr., a proportionately larger number of brine cooling pipes are required. MANUFACTURING APPLICATIONS. Figs. 325, 326, and 327 illustrate a method of cooling a ferment- ing room, which, as well as the pipe arrangement for vaults shown in Fig. 328, are constructed by the Frick Company, U.S. In the arrange- ment shown in Fig. 325 the coils are suspended from iron floor-beams, and are located in passage-ways and at the sides of the rooms, by which means any drip into the tubs is avoided, and free access to each tub is admitted of. Figs. 326 and 327 show in side elevation and transverse section the arrangement adopted for suspending flat pipe coils from ceiling on the iron floor beams. Fig. 328 shows in transverse section a pipe arrangement for a vault in a brewery, which will be readily understood from the drawing. In Figs. 329 and 330 is shown, in side elevation and plan, an automatic attemperation system with a cooling arrangement supplied by the same firm. In this system the ice-water for pumping through Figs. 326 and 327. Arrangement for Suspending Flat Pipe Coils from Ceiling on the Iron Floor Beams. Side Elevation and Transverse Section. the attemperators and regulating the temperature of fermentation is cooled in a cistern or suitable tank, provided with either a direct ammonia expansion or brine coil, supplied by the refrigerating machine, which is on the ammonia compression principle, the sweet or ice-water thus made being forced through the attemperators in the tubs, each or any of which can be shut off or regulated at will, the pressure and amount of cooling water being under automatic control of a self-acting pump and regulator which supplies the attemperators and needs no attention, whether one tub or many be in use. In Fig. 331 is shown the arrangement of an apparatus for cooling water for refrigerating and attemperating purposes in a brewery by means of an ammonia absorption machine of the Pontifex-Wood type. In the illustration H is the water service pipe from the company's main or from other source of supply ; I is the cooled water pipe leading 452 REFRIGERATION AND COLD STORAGE. from the cooler D up to the ice-water tank J, in which the cooled or refrigerated water is stored to be drawn off as may be required for refrigerating or attemperating. A thermometer is fitted on the pipe I at the outlet from the cooler, and a regulating cock or valve on the pipe Fig. 328. Pipe Arrangement for Vault in Brewery. Transverse Section. H, by which the supply can be so adjusted as to admit of the cooled water being delivered at any predetermined temperature. The water from the supply pipe H is run direct through the coil of the cooler D of the machine (which is placed on the ground floor of the brewery, and sufficiently near the steam boilers to admit of a supply of steam MANUFACTURING APPLICATIONS. 453 454 REFRIGERATION AND COLD STORAGE. Fig. 331. Arrangement for Cooling Water for Attemperating Purposes in Breweries with Ammonia Absorption Machine. MANUFACTURING APPLICATIONS. 455 being obtained for use in the generator), from whence it passes reduced to a temperature of 45 or 50 Fahr., or to any other desired lower temperature, to the tank j, which is at a sufficient elevation to com- mand the refrigerators and attemperators, and from which, as above- mentioned, it can be drawn off as wanted. The tank j is fitted with a suitable lid or cover, and is preferably constructed of wood, or of iron lagged with wood and sawdust. A is the condenser, B the separator, c the condenser, D the re- frigerator, E is the absorber, and G is the economiser. A full description of the Pontifex-Wood ammonia absorption machine has been already given in a previous chapter. In working an arrangement of this description the machine is started in the morning sufficiently early to admit of the ice- water tank J being filled up by the time the refrigerators are set to work. The machine is kept in operation until the refrigerating is done, and for a sufficient length of time after to admit of the tank j being filled up again, so as to provide a sufficient supply of ice- water for the use of the attem- perators during the night and until the machine is again started next day. It is stated by the makers that when the tank j is properly con- structed as regards insulation, it has been constantly found in practice that the rise in temperature of the water is not more than 1 Fahr. during a stoppage of from twelve to twenty-four hours. The ice-water from the tank J is forced through the attemperators, due provision being made for enabling the supply to each of them being suitably regulated, or cut off altogether if desired, independently of the others. The pump for circulating the ice- water through the attemperators should be self- acting and provided with an automatic regulating device, thereby enabling it to act efficiently whether one or all the attemperators be at work. The results obtained by the use of an arrangement of the descrip- tion described are, in addition to a marked improvement in the quality of the beer, that there is .a complete control over the refrigeration and fermentation, the beer refrigeration can be performed in a very much shorter time, and consequently, the day's work completed sooner, and, lastly, that the waste occasioned by the necessity for passing the greatest possible quantity of the comparatively hot water through the refrigerators and attemperators is obviated. This latter item alone is by no means insignificant, the saving where water companies' water is employed for refrigerating and attemperating being generally more than half. In large breweries where several machines are employed they are kept running continuously day and night. 456 REFRIGERATION AND COLD STORAGE. THE COLD STORAGE OF HOPS. Refrigeration has been found to be an excellent means for keeping hops from degenerating, and to effect this purpose a dry, dark room, thoroughly well insulated, and maintained at a temperature of from 23 to 34, is found to be the best. Either artificial or mechanical refrigeration, or ice, may be employed for cooling purposes, the first- mentioned being far superior. Before being placed in the cold storage room or chamber the hops should be thoroughly dried, sulphurised, and properly packed. Writing on the above subject in La Revue Generale du Froid, M. A. Mertus, Brewery Engineer and Professor of Brewing at the University of Louvain, states that hops should be moderately com- pressed and stored in a temperature maintained constantly between freezing-point and 37 Fahr., with a perfectly dry atmosphere frequently renewed. Brewers should use hops as soon as possible after leaving cold storage, and they should be kept cool and dry and preferably in the dark. Hops intended for small consumers should be stored in bales of not over 112 Ibs. weight, and be delivered as required. AMOUNT OF PIPING REQUIRED IN BREWERIES. Without knowledge of all of the elements affecting the cold losses, of course, only general statements can be made. The following data given by Mr F. E. Matthews in an article upon this subject, which appeared in Power, New York, will be of interest however : The logical way of computing pipe areas, says Mr Matthews, is first to calculate the amount of heat entering through the walls of the cellar, and add to this the amount of heat generated by the fermenting wort. For a given back pressure and known number of hours of operation of the refrigerating machine, it is then a simple matter to calculate the amount of pipe required. The estimate of the pipe area is based on the amount of heat that will pass through the metal of the pipe due to the difference between the temperature of the brine or ammonia on the inside and that of the air on the outside. The amount of piping depends on the wall area, insulation efficiencies, and differences in temperature. When these factors are not all known, rough rules in the form of ratios may be used. A fermenting room, for example, maintained at a temperature of from 36 to 40 would be piped according to the practice of one large MANUFACTURING APPLICATIONS. 457 builder of refrigerating machines, on a ratio of 1 to 14 ; that is, 1 run- ning foot of 2-in. direct-expansion pipe for every 14 cub. ft. of space. For piping the different cellars in a brewery the following ratios will offer at least a rough guide, it being understood that they may not fit particular cases, and that it is desirable, when it is possible to determine the areas, differences in temperature, and nature of the insulation of each wall, floor, and ceiling, to compute the cold losses through the walls. Then, after determining the ammonia back pressure and temperature, the required number of square feet, and, finally, the number of lineal feet of heat-absorbing pipes may be ascertained. The table will serve as a guide in laying out the piping for brewery cellars of from 10,000 to 40,000 cub. ft. in size. RATIO OP PIPING FOR BREWERY CELLARS. F. E. Matthews in "Power." Kind of Service. Cubic Feet per Foot of Piping, Rooms 1,000 to 4,000 Cubic Feet. Tempera- ture. Fermenting - - -I 2-in. direct-expansion pipe 13 '5 to 14.5 IJ-in. brine pipes - - 7 '5 8*5 } 36 to 40 Storage cellar - - -j 2-in. direct-expansion pipe 21 26 l-in. brine pipe - - 12 16 } 32 34 Chip cellar - - -j 2-in. direct-expansion pipe 24 30 l|-in. brine pipe - - 14 18 | 34 36 Racking room - - -! 2-in. direct-expansion pipe 12 15 l|-in. brine pipe - - 7 9 | 34 36 The approximate allowance per ton capacity to be made when selecting a machine for refrigerating beer wort is 15 barrels per ton on Baudelot cooler. One thousand gallons of sweet water per ton from 70 to 40. Climate construction and exposure of buildings to be refrigerated, character of the insulation, management and method of handling work, &c., must of course be considered. A ready method of obtaining a rough estimate in tons of the amount of refrigeration required in a brewery is to divide the capacity of the brewery in barrels by four. ICE-MAKING IN BREWERIES. Another obvious application of refrigerating machines in breweries, though one of secondary importance, is that of making small quantities 458 REFRIGERATION AND COLD STORAGE. of ice, either for use in keeping yeast cool or to send out to public- houses or for private use. This can be very easily accomplished with machines having a brine circulation. If only opaque ice be required, all that is necessary is to place galvanised iron pails, moulds, or cans of the shape of which the blocks of ice are desired, and filled with water in the brine tank, and the water will be frozen in a few hours into solid blocks of ice, which can then be loosened by dipping in warm water and turned out of the cans, the latter having a slight taper to admit of this being more readily performed. When, however, Fig. 332. Triumph Ice Machine Company, Small Brewery with Refrigerating Machinery working on the Direct Expansion System. Sectional Elevation. clear, transparent crystal ice is desired, it is necessary to use de-aerated water, or to keep the water in motion whilst freezing, and some special apparatus is consequently required, such as will be found described in the chapter on Ice-making. In Fig. 332 is illustrated in sectional elevation a complete small brewery fitted with refrigerating machinery on the direct expansion system as designed by the Triumph Ice Machine Company, U.S. This cut gives a good idea of the general arrangement of the plant in such a brewery ; for large breweries it will of course differ to a greater or lesser extent, depending upon the size, capacity, &c. MANUFACTURING APPLICATIONS. 459 REFRIGERATION IN CANDLE AND PARAFFIN OIL WORKS. Further important applications of refrigerating machinery to manu facturing purposes are In candle works, for the extraction of the solid stearine and paraffin ; and in paraffin oil works, for enabling refiners to extract in an economical manner in the presses a greater quantity of paraffin than is obtainable in any other manner, and also to obtain a product of a superior quality. The first type of refrigerating machinery used for the extraction of solid paraffin was, as has been before mentioned, a Harrison ether machine, and the mode of application is described by Dr A. C. Kirk as follows : "In 1861, when I applied an ether machine to the cooling of paraffin oil in order to extract the solid paraffin it was, as far as I know, the first application of a refrigerating machine to manufacturing purposes. " Paraffin oil consists of a mixture of many oils of various specific gravities, and contains in solution many solid paraffins of different melting points, some crystallising from the oil at a low temperature, and some at a comparatively high one. This crystallisable paraffin has to be extracted from the oil, as much to render the oil fluid at all ordinary temperatures as to secure the valuable solid paraffin which is so largely used for candle-making. " As paraffin and paraffin oil are very bad conductors of heat, it was from the first evident that in cooling it artificially the heat to be removed could not pass through a layer of any considerable thickness but at a very slow rate. In my earlier arrangements pipes, closed at the bottom and opened at top, depended vertically from an iron tube plate, and, by suitable arrangements, a current of cold brine was main- tained through these pipes. The pipes hung down into a wooden box, which was filled with paraffin oil, and, after standing a certain time, the oil was cooled and the paraffin was crystallised from its solution in the oil, the whole forming a pretty firm pasty mass. An iron scraper plate fitted these tubes, and being attached to the box and drawn down with it as the box was lowered, forced this frozen paraffin down from between the tubes, and it fell into the bottom of the box. "This arrangement worked until it was entirely burned down. When it came to be reconstructed, I adopted a more speedy plan. I used a drum, with cold water circulating in it, or it might be cold brine, and as this drum revolved, the lower part of its circumference dipped into a small pan containing the paraffin solution. A coating 460 REFRIGERATION AND COLD STORAGE. adhered to the drum, was cooled as the drum revolved, on the opposite side was scraped off continuously and fell into a tank below. By this means a continuous process was substituted for an intermittent one." An ordinary arrangement for the extraction of solid paraffin from shale oil is shown in Fig. 333, wherein A A are the cooling drums or cylinders, B B the troughs or receptacles intended to contain the oil to MANUFACTURING APPLICATIONS. 461 be treated, and c c scrapers for removing the partly solidified oil from the drums or cylinders A. The operation of the apparatus is exceedingly simple, a circulation of brine, first reduced to about 10 or 12 Fahr., or other desired tem- perature, in the usual manner, is afterwards passed through the set of cooling drums or cylinders A, entering each of the latter at one of the hollow trunnions or gudgeons, and leaving at the other. The lower portions of the drums or cylinders A dip, as shown in the drawing, into the open shallow troughs B, one of which is placed below each drum, and in which the oil to be cooled and treated is placed. The surfaces of the drums or cylinders A during their revolutions are immersed in this oil, and become coated with a thin film of it, which is cooled by the circulation of the cold brine from the machine, and reduced in tempera- ture during the continuance of the revolution, until it is finally removed in a pasty condition by the scrapers c, one of which is arranged to press against the periphery of each of the drums or cylinders. The remaining oil is then drawn away by plunger pumps, and forced through filter presses, which separate the paraffin wax crystals or scales from the oil. The employment of a refrigerating machine of one type or another in a works engaged in the production of paraffin is, and indeed has been for some years past, deemed indispensable, and but few manu- facturers now endeavour to do without it. Indeed, the development of the paraffin industry dates from the time when an ether machine of the Harrison type was first used for this purpose, which, as already men- tioned, was in 1861. REFRIGERATION IN ARTIFICIAL BUTTER FACTORIES. In the manufacture of artificial butter a variety of ingredients are first melted and amalgamated together at about blood heat in churns, and the resultant mass is then mixed with and run out into ice-cold water contained in open troughs. This sudden application of intense cold crystallises and granulates the artificial butter, which is then skimmed off, and at the same time it also washes out the buttermilk, which otherwise, by its rapid decomposition, would taint the butter. Primarily, and indeed still to a considerable extent, the means adopted for reducing this w^ater to the requisite temperature is the application of natural ice, which is placed in tanks partially filled with water, and by melting imparts its cold to the latter. This plan, however, is open to several serious objections, amongst which may be mentioned : The excessive cost of the ice and of the necessary labour 462 REFRIGERATION AND COLD STORAGE. for handling it ; the impossibility of thus obtaining as low a temperature as is desirable, the best result being the mean of the two temperatures of the ice and the water ; the non-attainment of a regular temperature continuously ; and, finally, that the natural ice is always more or less Fig. 334. Refrigeration Arrangement in an Artificial Butter Factory. Sectional Elevation. dirty, and renders the cooled water so also, and consequently soils and spoils the colour and appearance of the artificial butter. Figs. 334 and 335 illustrate a refrigerating installation in an artificial butter factory. In the arrangement shown in Fig. 334 a circulation of brine, reduced to a low temperature (about 20 Fahr.) in the evaporator or MANUFACTURING APPLICATIONS. 463 refrigerator of a Pontifex-Wood absorption machine, or of a compres- sion machine, is forced by a brine pump through the pipe i to the bottom of the refrigerator L, the construction of which latter is more clearly shown in the enlarged view thereof, Fig. 335. It consists of 464 REFRIGERATION AND COLD STORAGE. sets or rows of horizontally arranged copper or brass tubes, secured at their extremities in return heads, and through which the cold brine from the cooler passes. Over these tubes the supply water is allowed to trickle into the cooled or ice- water tank M, from which it is drawn off as required for the use of the churns through the pipes N. In this manner a steady and constant supply of clean cooling water at a tem- perature as low as 32 '5 Fahr. is ensured. The brine returns to the pump from the top of the refrigerator L through the pipe J. In factories where the practice of using water cooled down only to 39 or 40 Fahr. prevails, the brine refrigerator L can be dispensed with and the water to be cooled may be simply run through the pipes in the cooler as in the arrangement in a brewery for cooling water for refrigerating and attemperating, shown in Fig. 331. For holding artificial butters in cold storage for lengthened periods the temperatures recommended for both butterine and oleomargarine are 20 to 35. REFRIGERATION IN TEA FACTORIES FOR REGULATING THE TEMPERA- TURE OF THE OXIDISING OR FERMENTATION OF TEA. It is found desirable to maintain the atmosphere of the fermenting rooms in tea factories situated in the low countries or plains at the same temperature as those of factories situated in the hills, and this can be advantageously carried out by means of mechanical refrigera- tion. A patent for an arrangement of this description has been obtained by Mr H. T. Armitage, of Halton. By means of this process water tanks, cold cloths, fans, &c., can be dispensed with, and the oxidation or fermentation carried on instead in a cold room, the temperature of which need not be reduced below 45, at which point it has been found that fermentation ceases. A plant erected by Mr Armitage, for the above purpose, consisting of a Schou's patent ammonia com- pression machine, made by Tuxen & Hammerich, having a cooling capacity sufficient to maintain a room of about 3,800 cub. ft. at 40, with the temperature outside at about 70 Fahr., and requiring about 2J H.P. for driving purposes, is found capable of cooling about 250,000 Ibs. of made tea per annum. REFRIGERATION IN SUGAR FACTORIES AND REFINERIES, FOR THE CONCENTRATION OF SACCHARINE JUICES. Refrigeration is used in sugar factories and refineries for the concentration of saccharine juices and solutions by freezing or con- MANUFACTURING APPLICATIONS. 465 gealing the watery particles, which are then removed, leaving the residuum of a greater strength. A method of concentrating saccharine juices by freezing or congealing and decantation, devised by Mr F. Monte, is thus described in "La Sucriere Indigene et Coloniale." The freezing tank is fitted with two twin coils placed alongside each other, and in which the refrigerating liquid or medium is caused to circulate alternately from the external walls of the tank towards the centre and the reverse, for the purpose of producing layers of ice of equal thickness. The different layers of the liquid are reduced in temperature from the top downwards to the bottom, one after the other, the temperature of the refrigerating agent or medium gradually decreasing. In this manner a larger amount of the juice is frozen or congealed without the formation of an impenetrable mass of ice. The coils of pipe which serve as refrigerating coils for the concentration of the saccharine juices, are subsequently employed to cool the refrigerating liquid or medium itself. The freezing or congealing tank comprises a vessel having separate coils of pipe placed at different heights therein, the circulations being arranged to take place, as already mentioned, from the exterior towards the centre. A battery or set of these tanks are connected up in series so that the freezing or congealing and the concentration can be carried out uninterruptedly, and that the ice formed and remaining after the removal of the concentrated liquid may subse- quently be used to reduce the temperature of the refrigerating liquid or medium without there being any necessity for the removal of the ice. REFRIGERATION IN BLAST FURNACES FOR DESICCATING AIR AND PRODUCING A DRY BLAST. Refrigerating machinery is becoming largely used for desiccating the air for use in blast furnaces, and producing a dry blast. To remove the moisture from the air the latter is reduced in a suitable cooler to a temperature below dew point. The surplus moisture in the air is precipitated upon cold surfaces, and the air leaves the cooler nearly saturated, and at a comparatively low temperature. The percentage of saturation remains constant so long as the temperature is the same. In the case of coolers of the "dry" type working at moderately low temperatures, a portion of the moisture precipitated is deposited upon surfaces in a liquid state, and can be drained off. The 3 466 REFRIGERATION AND COLD STORAGE. remaining moisture is precipitated in the form of snow, and must be removed from the snow boxes from time to time. In coolers of the so-called " wet " type, the air is brought into contact with an uncon- gealable brine bath, which absorbs the surplus moisture. The brine becomes weak from dilution, and has to be periodically reconcentrated either by the addition of fresh salt or by evaporation. An objection to the " wet " type of apparatus is the possibility of brine being carried away in a finely divided state with the currents of cold air. The advantages of desiccated air are as follows : A reduction of about 15 per cent, in the consumption of coke, and an increase of from 10 per cent, upwards in the production of iron, according to the nature of the furnace, character of the ore, and other conditions. The furnace is more regular and uniform in its operation, and will hold the zone of fusion more steadily nearer the tuyeres. The life of the furnace lining is also lengthened, by 20 to 30 per cent., according to the working conditions. The use of desiccated air enables a much higher heat temperature to be employed, and also ensures an economy of from 5 to 10 per cent, in the limestone used for fluxing purposes. There is also found to be a marked regularity in the silicon and sulphur content of the pig iron, which is a very important point, and also a considerable reduction in the flue dust owing to the concentration of the heat at the tuyere zones, which causes regular operation, and prevents slipping or scaffolding in the furnace. The flue dust may be reduced as much as 50 per cent, by careful working. The use of desiccated air also gives greater economy in the working of the blowing engines, the speed of which may be reduced as much as 15 per cent. Figs. 336 and 337 show a large ammonia (NH 3 ) plant on the Haslam system, erected at the Spring Vale Furnaces, Wolverhampton, belonging to Messrs Alfred Hickman, Ltd. The installation is capable of desiccating 100,000 cub. ft. of air per minute, entering the batteries at 90 Fahr., and reducing same to 20 Fahr., with a satura- tion of 1'3 grains of vapour per cubic foot. This apparatus, which has been in operation for some time, is found to give excellent results, and, if required, a lower temperature than 20 can be obtained. The desiccated air is delivered to five furnaces, and also to the steel works for use in the converters. The installation comprises six duplex ammonia compressors driven by rope gearing from electric motors. The ammonia condensers are of the Haslam type, interlaced and without joints welded by electricity. The condensers are constructed to work with high temperature con- s I 1 I SI >j -*a f J .2 PQ 468 REFRIGERATION AND COLD STORAGE. -2 2 0} ^" s MANUFACTURING APPLICATIONS. 469 densing water, and the water pumps are driven by electric motors. The cooling of the air is effected by a Haslam patent air-cooling battery which consists of galvanised corrugated steel plates and direct expansion cooling pipes (see pages 294, 295). This battery is divided up into two sections, one for cooling water and the other for cooling brine. In the first section the air is cooled from 90 down to from 36 to 38, and here the greater part of the aqueous vapour is extracted. The air then enters the second section at a temperature of from 36 to 38, and is cooled by brine to 20, or lower if required, and the remainder of the vapour extracted. The advantage of this arrangement is that the air deposits the great part of its moisture in the first cooler, and only a relatively small amount is extracted in the second cooler. A special brine concentrating apparatus is provided, so that any water accumulating in the brine can be evaporated, which admits of the brine being kept at a regular specific gravity. REFRIGERATION IN WINE MAKING. The following is an abstract of an interesting article on the use of refrigeration in wine making which appeared in the Revue Generate du Froid, Paris. Substances contained in saturation in the must of grapes become indissoluble when the temperature is reduced, and 2 to 3 grammes of cream of tartar have been in this manner obtained per litre of must of Burgundy wines. The gums, mucilages, and albuminous matters being acted on at the same time. Precipitations of mineral and organic substances create an inductive force acting on the matters in suspension, the deposit and the clear liquid becoming separated in respectively varying volumes, and low temperatures having an intense defecating action. Cold augments the supersaturation of the mineral substances of the must, which has a great affinity for them, whilst the combinations of air and must are the slower the lower the temperature. This slowness of oxidation is an important feature. The action of cold may be helped by that of heat. Clear clarified must heated to 60 forms a second coagulation, the precipitation of which is aided by cold. The two actions of refrigeration and Pasteur- isation may be thus combined, and a clear must deprived of many substances destined to be afterwards precipitated be obtained. In order to multiply the ferments, if the Pasteurisers are not dis- pensed with it is necessary to clarify and relieve the must of the 470 REFRIGERATION AND COLD STORAGE. greater portion of its germs. The best method consists in lowering the temperature to 4 or 5 or even to if possible, with the addition of from 3 grms. to 5 grms. of liquid sulphurous acid per hectolitre of must. The defecation of cold has generally the result of taking from wine any earthy taste. Gatherings of grapes changed or decomposed are greatly benefited by refrigeration of the must before fermentation. The oxidising substances which impregnate mucilages are precipitated in the lees with a portion of the hurtful particles, likely to impart disagreeable flavours. The growers would find it advantageous to submit the must of white wines to the action of cold on coming from the press, until it turns limpid. Fermentation after drawing off clear should be allowed, and the ferments added will act more efficiently. White wines ferment in large vats at temperatures exceeding 32 to 35. A low temperature preserves the aroma produced by the ferments, and refrigeration by means of water is, as a rule, insufficient in practice for the maintenance of a suitable temperature. On leaving the fermenting vats, white and red wines throw down important deposits. The wine deposits its gross lees during the first month. At the end of six months the wine has made a series of deposits and assumes a limpid nature. The wine-grower dares not hasten young wines. With the help of refrigeration, however, a more complete and regular clarification can be obtained than that produced by six months of rest. Besides which, the lees or dregs are reduced to a minimum, and are heavy and concrete. The diminution of lees, especially in the case of raw wines, repays to a great extent the cost of refrigeration. The wines thus freed may be immediately used, and under this head there is a saving in cellarage for the producer. In the year 1860 the use of cold for the congealing and concentration of wines was predicted by Yergnette Lamothe in Burgundy. As large quantities have to be cooled, it is advisable to take measures to recover the cold, and the cooled wine may be used as a source of cold by means of temperature exchangers. The must is drunk in France under the name of unfermented wine, "vin bourru," "macadam," " vin doux." Towns like Paris, Lyons, and St Etienne, receive entire train loads of must from the south or special centres, such as Bergerac. In South America must is consumed after heating it over an open fire to impart keeping qualities and to give it a special flavour. Up to the present the practice has been to forward in tuns from Vignoble the must coming from the press. The MANUFACTURING APPLICATIONS. 471 tuns are first either strongly fumigated, or treated with bisulphate of potash. Refrigeration is, however, the best means for transporting must to a distance. Must cleansed with 10 grms. of liquid sulphurous acid per hectolitre, Pasteurised in the same way as wine and cooled to 8, may be transported to any distance in waggons properly arranged. The concentration of wine by means of artificial cold had already been suggested by Baudoin and Schribaux ; and M. Pacottet again in 1895 arrived at the same conclusions with respect to the problem: (1) The freezing point is lowered in correspondence to the alcoholic contents, a wine having 7 per cent, of alcohol commencing to freeze at - 2 with formation of little crystals of ice ; at 1 1 per cent, of alcohol the freezing temperatures falls to - 5 and - 6. Concentra- tion by cold therefore calls for very low temperatures, and is conse- quently onerous. (2) If the crystals of ice be separated from the rest of the wine, drained, and then submitted to an energetic whirling, they will be found to retain quantities of alcohol often exceeding 1 per cent, and also colouring matters. (3) Wine concentrated by congelation has a turbid appearance. After a certain period of repose it throws down an abundant deposit formed chiefly of organic matters, of tartar, and of colouring matters. If the concentration be carried to any length, the wine deteriorates with considerable rapidity, and assumes at the end of a few months the yellow tint characteristic of stale wines. To sum up, concentration by freezing entails considerable losses in alcohol, of colouring materials, and of tartar. The concen- tration of musts by means of cold is not yet developed on an industrial basis. The operation calls for special plant, and has to compete with concentration in vacuum at 40 to 44. In a country such as the Argentine, however, where fuel is scarce and water power cheap, cold might be used economically as a concentrating agent. Its use affords the advantage of producing musts which are less acid than those produced with heat as the agent. VARIOUS OTHER MANUFACTURING AND INDUSTRIAL APPLICATIONS. Amongst the numerous other manufacturing and industrial appli- cations of refrigerating machinery, mention may be made of the following : In dynamite factories for maintaining the dynamite at a low temperature during the process of nitrating. In manufactories of photographic accessories for cooling the gelatine dry plates. 472 REFRIGERATION AND COLD STORAGE. In soda-water works for cooling soda or mineral waters before bottling. In chemical works for the reduction of mother liquors at low tem- peratures, thus hastening crystallisation, and augmenting the amount of crystals produced, as well as reducing the cost of production. In addi- tion, however, to substances the crystallisation whereof is facilitated by cold, it can be also advantageously employed for the congelation of various chemicals, and for other purposes. In india-rubber works for the curing and hardening of blocks of india-rubber, thereby facilitating the cutting of same into sheets for the manufacture of various elastic articles, the material in that state admitting of it being worked up in a much superior manner, and, moreover, at a far lower cost. In glue works for drying the gelatine, and so admitting of the use of less concentrated solutions. And also in numerous other industries, in which it would be im- practicable to carry out many of the manufacturing processes in the summer months without the employment of some artificial means for cooling. For the purification of gas intended for the inflation of balloons by the removal of tarry matter, &c., therefrom, and also for drying the gas by the elimination of the greater portion of the aqueous vapour present in ordinary coal gas as usually commercially manufactured, and in this manner greatly increasing its efficiency for the purpose in question. This method has been proposed by Mr C. Lambert. In tropical and other warm climates for cooling the atmosphere of hospitals and public buildings. For the regulation of plant growth by retarding the growth of bulbs and flowering plants to produce blossoms at any time of the year desired, and to fruit trees, so as to enable fruit to be obtained at any season. In laundries for effecting the white bleaching of clothes, and for drying them, the latter operation being performed by means of a con- densing plate. For freezing bait in northern waters. At the present time a cold store of considerable size is being erected in the Westmanna Islands intended for the preservation of herrings for use as bait in the Iceland line fishing. For the preservation of furs, and various fabrics such as carpets, rugs, silks, tapestries, and upholstered furniture, from the ravages of moths and beetles, and in the case of silks to prevent them from losing- weight and to preserve their gloss or lustre. Furs should be kept in CONSTRUCTIONAL APPLICATIONS. 473 dark chambers at a temperature of C. ; small articles in cases with layers of paper between, larger ones hung independently. For cooling the holds of vessels carrying live cattle, in which manner a uniform temperature of about 70 Fahr. can be maintained throughout the entire voyage (instead of its rising to over 100 as it otherwise would), thus entirely obviating the heavy losses of cattle usually experienced from the high temperature and bad ventilation. It might also be advantageously applied, on large passenger steamers, to cool and ventilate the saloons and state-rooms, as also the engine- rooms, &c., when in hot latitudes. And finally, for producing artificial surfaces of ice in inclosed places, so as to provide skating rinks upon which this pastime may be enjoyed during the mildest winters, or at any season of the year. Such an installation was erected some years ago at the Niagara Hall, London, of which the following is a brief description : The plant consists of ammonia compression machines of the De La Vergne type, the ice-making capacity of which is of 12 tons per day each. The rink itself, when in everyday use, requires the expendi- ture of a refrigerating power equal to that consumed in the manufac- ture of 8 tons of ice per day, and the balance of power, which is con- siderable, is employed in the manufacture of block ice, and in main- taining the cold storage chambers in connection with the rink at the required temperature. The congelation or freezing of the water to form the ice surface of the rink is effected by a network of pipes which are laid upon the floor of the rink, and through which brine, reduced to a sufficiently low temperature in the refrigerator of the machine, is kept in constant circula- tion by means of a suitable brine pump. The non-congealable liquid or brine employed in this instance is a strong solution of calcium chloride. The operation of the ammonia compression machines employed for this purpose differs in no way from the description already given when dealing with that type of machine! CONSTRUCTIONAL APPLICATIONS. For the freezing of loose ground in quicksand soils, in order to facilitate sinking colliery shafts, well-sinking, tunnelling, or putting in foundations, wherever the amount of water is too great to be pumped or in cases where the removal thereof would damage existing founda- tions, to avoid the necessity for expensive underpinning, &c. This may be effected either by means of ammonia or cold-air machines. 474 REFRIGERATION AND COLD STORAGE. In the case of a quicksand in a well, a coil of pipes, of a somewhat larger diameter than the lining of the well, is usually sunk into the quicksand, and the latter frozen by a circulation of cold brine through the coil. The necessary excavation can then be proceeded with, and as soon as the lining is put in, the circulation of brine is stopped and the coil withdrawn. TUNNELLING. During the construction of a tunnel for foot-passengers through a hill in Stockholm this method was employed for driving the tunnel through about 80 ft. of loose ground, consisting of gravel mixed with clay and water, which possessed so little cohesion as to render the ordinary method of excavation impossible. The refrigerator employed was a cold-air machine of the Lightfoot type, capable of delivering 25,000 cub. ft. of air per hour, and the arrangement consisted in form- ing the innermost end of the tunnel into a freezing chamber by means of a partition wall made of a double layer of wood filled in between with charcoal. After the refrigerator was run continuously for sixty hours the gravel was frozen into a hard mass to a depth varying from 5 ft. near the bottom of the tunnel to 1 ft. near the top. The work was proceeded with in 5-ft. lengths, the excavation commencing at the top, and a temporary iron wall of plates 12 in. square was built up against the face from the top downwards as the cutting away of the gravel was proceeded with ; the arching of the tunnel was completed as quickly as possible close up to this temporary iron wall while the ground was still frozen. After being fairly started it was found sum cient to run the cold-air machine on the average from ten to twelve hours every night except after heavy rains, when much water perco- lated through the gravel. After two 5-ft. lengths had been excavated the partition was moved forward. The daily progress whilst employing the freezing process was on an average about 1 ft. A full description of the construction of this tunnel is given in the Engineer of 9th April 1886. And in the issue of 30th November 1883 of the same journal, will be found an interesting account of the Poetsch method of sinking colliery shafts by freezing the soil by means of an arrangement consisting of a series of vertical iron pipes placed in a circle. SINKING SHAFTS. A very interesting account of the more recent applications of the Poetsch process in France has also been given in a paper upon the CONSTRUCTIONAL APPLICATIONS. 475 use of freezing machinery for sinking through water-bearing strata by F. Schmidt,* of which an abstract is subjoined. The Poetsch process was first employed in the Houssu coalfields of Hainault in 1885, having been introduced into France at a later date, viz., 1890, and since extensively employed for sinking pits through the Tertiary and Cretaceous strata above the coal measures at Vendin-Sens, Dourges, Courrieres, Vicq-Anzin, and Flines-lez Raches, the pits being respectively 82 and 84, 47, 45, 102 and 102, and 70 m. in depth. The latter was the most difficult undertaking. The permeable strata to be got through were 70 m., blue marls affording a bearing for tubing at 72 to 79 m. ; the Tertiary sands and clays were 25 m. and the chalk about 50 m. in thickness. At the junction of these forma- tions a heavy sheet of water was encountered, which gave from a single bore-hole a flow of 1,200 cub. m., which rose to 2 m. above the surface ; a second one in the lower portion of the chalk between 65 and 70 m. also overflowed. Two brick towers were constructed round the mouth of the pit viz., an inner one of 6 m. and an outer one of 11 m. in diameter, and rising the one 1*6 m. and the other 2 '6 m. above the level of the surface with the object of arresting these feeders, but were found to be ineffectual and incapable of maintaining the water level constant by reason of a lateral flow joined to subsidence which was set up in the overlying strata of sand, the arresting of which necessitated the sinking of a special bore-hole so as to trap the spring at a distance of 25 m. eastward from the pit, by which means a steady head of 1*6 m. of water was got in the towers, and the freezing operation could be commenced. The freezing circuits were twenty-two in number, contained in bore- holes 75 m. deep, one of which was located in the centre of the pit, which was 4'2 m. in diameter, the remaining twenty-one being arranged in a ring 6 m. in diameter. An ammonia-compression machine of the Fixary type was used for the production of the necessary cold ; it was driven by a 500 x 900 mm. single-cylinder engine, making eighty revolutions per minute, and capable of producing cold equal to 1 ton of ice made per hour. In thirty-eight days from the 1st September 1894, upon which date the freezing machine was started, the ice-wall was completed, and the sinking commenced on the 25th October, the relief or special bore- hole being stopped for good on the 5th November. At the upper strata the ground was broken up by means of picks and wedges, but at a lower level blasting by means of compressed powder was employed. * Bulletin de la Societt de V Industrie Mindrale, vol. ix., 1895, pp. 273-416. 476 REFRIGERATION AND COLD STORAGE. The central tube was disused and removed as the sinking progressed. When a depth of 14*8 m. was reached two oak seating rings, the one 22 x 24 cm. and the other 22 cm. square, were secured in position for the first line of tubbing, which was composed of segments of oak 1 6 cm. to a height of 2 '6 m. above the surface level, with a 16 cm. backing of concrete increased to 70 cm. near the surface. A second seating with curbs of 22 x 24 cm. and 22 x 20 cm. was fixed at 25-93 m., and a third at 43-82 m., which latter had three seating rings respectively, of 22 x 28 cm., 22 x 24 cm., and 22 x 22 cm. in section, the tubbing rings being of 18 cm., with the same thickness of concrete behind. By April 1895 the pit was sunk to a depth of 70 m., and on the 1st May the building of the tubbing was completed. Light was provided by incan- descent electric lamps supplied with electricity from a dynamo situated in the same building as the freezing machine. The cost of sinking in frozen ground per meter was as follows : Francs. Freezing - 1,550 Sinking 150 Tubbing 650 Concreting and sundries 50 2,400 per metre. The Poetsch method of sinking has been also lately successfully employed at the coal-field of Ligny-les-Aire in a sinking through a permeable covering of about 86 m., and in the repair of the cylinder pits of the Fontinette Canal lift. These pits, which were of 4 m. in diameter, were sunk by compressed air and tubbed with cast iron between 1883 and 1887. In 1893, however, owing to an irregular subsidence of the ground, they became leaky, and it was decided to replace the iron lining by one of brickwork of 80 cm. in thickness, thus reducing the diameter from the original 4 m. to 3*7 m., with a considerable increase in the bottom bearing of the press, which was to consist of a cylindrical block of brickwork 5-307 m. in diameter and 2 m. in height. In the carrying out of these repairs it was decided to adopt the freezing process in preference to using compressed air, so as to avoid any chance of disturbing the ground, and thus causing damage to the neighbouring buildings. The work was commenced at the right-hand press, the boat-cradle being secured at its highest level by means of two supporting girders of 40 m. in depth; the piston was disconnected, and twenty bore- holes arranged on a circle of 6-307 m. in diameter, or 99 cm. apart, CONSTRUCTIONAL APPLICATIONS. 477 and one placed centrally, were provided for freezing. These bore-holes were about 2 m. deeper than the bottom of the new foundation, and lined with tubes of 150 mm. in bore and of 5 mm. in thickness, formed of steel. The freezing tubes were likewise of steel and 125 mm. in diameter, and the inside brine supply pipes of iron and 33 mm. in diameter; the collecting rings were of 100 mm. bore by 5*050 m. diameter on the admission, and 5*7 m. diameter on the return circuit. Mr Schmidt does not think that the methods of working proposed by Mr Gobert and Mr Koch are likely to afford as favourable results as are obtainable by the original method. The first of these gentlemen proposes to volatise the liquefied ammonia in the freezing circuits ; and the latter depends entirely upon gaseous expansion. The paper also contains descriptions of the combined method of freezing and fire-setting in frozen ground used for prospecting for gold in the alluvial deposits of the Siberian rivers during the winter. The following extracts are taken from an account of Mr Gobert's system * given in " The Colliery Manager's Handbook " : This is a modification of the Poetsch congelation method, and is specially applicable to the sinking of shafts through shifting sands and water-bearing strata. Fig. 338 is a vertical section and Fig. 339 a plan showing the refrigerating plant and the shaft to be sunk, the two being as near each other as possible, and the shaft being lightly roofed over as a protection from the weather. The power of the steam engine required varies with the diameter and depth of the shaft to be sunk, and need not exceed 40 H.P. unless the shaft is deep. The steam engine and compressor are placed horizontally side by side and connected to the same shaft, with a fly-wheel and pulley for belting between them. Liquid ammonia is forced by the compressor through the series of wrought-iron tubes of the condenser, first to the reservoir, which acts as a kind of governor, and then by the lower of the two pipes seen in the vertical section to the system of congelation tubes round the shaft. Great heat results from compressing the gaseous into liquid ammonia, and in order to abstract it, the condensers have a relatively large surface, and cold water is caused to circulate freely round them. This water is kept in a state of agitation by means of the small water wheels with floats, shown in the drawings, driven by belts off the pulley on the main shaft. * For further description and illustration of the system see "The Colliery Manager's Handbook," by Caleb Pamely, M.E., published by Crosby Lockwood & Son, London. 478 REFRIGERATION AND COLD STORAGE. The machinery, by means of the upper of the two pipes seen in the vertical section, exhausts gaseous ammonia from the congelation tubes, sunk vertically beneath the surface of the earth round the site of the shaft, and forces it, condensed into a liquid form, first through the apparatus for separating the oil (see Fig. 339), and then into the condenser. CONSTRUCTIONAL APPLICATIONS. 479 The compressor piston is freely lubricated with mineral oil, and some of the ammonia comes into contact with and is absorbed by it. The mixture might choke the tubes of the condensers, and pos- sibly even reach the congealing tubes, if the two substances were not separated. This is effected chiefly by the oil-separator, but, as an additional precaution, a space is provided at the bottom of each congelation tube for the reception of any oil that may be carried 480 REFRIGERATION AND COLD STORAGE. there. The oil retained in the separator is not effectually separated from the ammonia, but is slightly mixed with it. This ammonia, how- ever, is recovered in the purifier, where it is driven off by distillation. The distillation is effected by means of a worm through which steam from the boiler circulates; the ammonia vapour is led by a small curved pipe, seen in Fig. 338, into the main pipe leading the gaseous ammonia from the shaft to the compressor. Over the centre of the area forming the intended shaft are two pipe-rings, the lower of which is in connection with the ingoing pipe, and receives the liquid ammonia, and afterwards distributes it by the radial pipes to the vertical congelation pipes sunk in a circle below the surface of the earth. The upper ring is in connection with the return pipe, and forms a receiver for the collection of the gaseous ammonia from separate orifices in the same congelation tubes after it has by evaporation in these tubes produced the desired refrigerating effect. The gaseous ammonia is drawn from the upper ring pipe to the con- denser through the return pipe. The liquid ammonia is not allowed to fall to the bottom of the tube and collect in a mass, but in order to cause the evaporation of the greatest possible amount of liquid in a given space of time, the small pipe for leading the freezing liquid through the tube is made to assume either a wavy or a spiral form, as shown in Figs. 340 and 341, in which A represents the congealing tube, B the pipe for leading the freezing liquid, and c small holes for allowing the liquid to escape into the tube, at points more or less frequent, as may be desired. The injecting pipe is led down nearly, but not quite, to the bottom of the congealing tube and both pipe and tube are closed at the bottom. The entrance of the congealing liquid into the injecting pipe is carefully regulated, and descends slowly in a thin stream, the flow being retarded by the waves or spirals, and giving up a part of itself at intervals. The source of heat necessary for evaporating the liquid is the higher temperature of the surrounding strata, and this heat passes not only through the thickness of the congealing tube, but also across the frozen wall which soon surrounds it. By- this arrangement the liquid to be evaporated escapes into the congealing tube at all depths simul- taneously, and the whole source of heat available is thus utilised at the same time for evaporating the freezing liquid. In other words, the refrigeration is effected simultaneously at all points. The diameter, number, and arrangement of the holes in the inject- ing pipe, and also the pitch of the spirals or undulations, are varied in accordance with the depth in order to produce a greater freezing effect CONSTRUCTIONAL APPLICATIONS. 481 -P 93mjn \9-44in. Fig. 340. Fig. 341. K 342. Gobert Congelation Method of Sinking Shafts. Details of Construction. 31 482 REFRIGERATION AND COLD STORAGE. at special points, or a uniform freezing, in accordance with the require- ments. A congelation may therefore be arranged to have the frozen column of larger diameter at the bottom than at the top, on the sup- position that the measures are of uniform consistency, in order that its stability may be maintained while the shaft is being sunk through it. The arrows in Figs. 338 and 339 show the course of the ammonia in its passage, as a liquid, from the compressor to the condensers, and then on to the congelation tubes, and also its return, in a gaseous state, from the congelation tubes to the compressor, to be again liquefied, and so on. The same ammonia serves indefinitely, with the addition of a small quantity to compensate for waste. The process requires a large quantity of cold water for use at the condensers, but this must not be drawn from any point so near the site of the shaft as to create a current, which might oppose and retard the congelation by licking or washing the congelation tubes, thus depriving them of their refrigerating effect, which would be carried away instead of going into the surrounding sand. When the wet sand or loose material has been frozen round the tubes, sinking may be commenced with a small windlass placed between the collecting and distributing rings and the circumference of the circle of congelation tubes. The men enter, and the excavated material is removed, laterally, near the surface, between two congelation tubes, where also access is obtained for the segments of tubbing. More important winding apparatus must, of course, replace the windlass when the sinking has reached a depth of 2 or 3 fathoms ; then, if the arrangements have been made judiciously and due precautions taken, the frozen mass will be so large as to require slighter refrigerating power to maintain it than that required for its production. This allows of the removal of one or two radial pipes for distributing the ammonia in order to allow of more space for the working of a winding engine. A great advantage claimed for the Gobert modification is that if the congelation tube be surrounded with water and there be a defective joint, the water will simply enter the tube, on account of the pressure therein being less than that outside. If such an accident occurs at all it is usually after congelation has proceeded for some time and the tube is already surrounded with ice ; there will then be no interruption in the work. The liquid ammonia always enters the tubes at a tem- perature above freezing-point, and in practice varies from between 20 and 35 Cent. (68 to 95 Fahr.). The cold produced is due to the liquid ammonia becoming volatilised in the tubes. CONSTRUCTIONAL APPLICATIONS. 483 It is of course impossible to entirely guard against leaky joints. The thrust of the superincumbent measures severely tries them, but special attention has been given to the design of the joints in order to increase their power to resist the strains to which they may be subjected. The method of connecting the ends of congelation tubes has been by screwing one end into another without internal sockets. The thinning of these tubes at the joints frequently causes them to break in being withdrawn from the ground. The form of joint used by Mr Gobert is shown in Fig. 342. Its chief feature is an internal collar, or ring, shown by crossed hatchings in the section. This collar has an outside flange of the same outside diameter as that of the tubes which it serves to connect. The flange is undercut on both sides so as to be of dovetailed section. Each end of a tube is also bevelled or curved off so as to afford with the collar flange a groove wider inside than out, holding and compressing the lead ring or washer instead of forcing it outwards, thus affording an absolutely tight joint when the ends of the tubes are screwed on to the collar. In some cases, especially for joining the smaller size of tubes, the internal collar is made without a flange, and then only one lead washer is used placed between the ends of the tubes, which must be bevelled and curved just the same as when the collar is flanged. On the tubes being screwed up, they squeeze the washer between them, just as the gland of a stuffing-box compresses the packing. The outer lines of the section, Fig. 342, shows the form and extent to which a tube was covered with ice after having been immersed for thirty-two hours in a tank filled with water; the ice weighed 62 kilogs. (137 Ibs.) at the end of the operation. If the tube had been immersed in wet sand instead of clear water, the congelation would have been more rapid. One of the two smaller tubes shown at the top of the congela- tion tube serves to introduce the liquid ammonia, while the other carries off the gas to the upper ring-pipe. Instead of ammonia, any other liquid susceptible of easily assuming the gaseous state, such as liquid carbonic acid or liquid anhydrous sulphurous acid, may be employed with a suitable modification of the engine. CHAPTER XIX ICE-MAKING Various Methods of Ice-Making The Can System The Wall or Plate System The Stationary Cell System Miscellaneous Arrangements for Making Clear or Crystal Ice by Agitation Holden System of Ice-Making Water De- aerating or Distilling Apparatus Vacuum System of Ice-Making -Imitation of Natural System Ice Factories Ice-Elevating and Conveying Machinery Ice-Making, General Brine Storing Ice Ice-Crushing or Breaking Machinery. THE specific gravity of ice made from de-aerated water is, according to De Mairan, -926; its specific heat is -504; at a temperature of 32 Fahr. 1 cub. in. = -033449 lb., 1 cub. ft. = 57 -789872 Ibs. ; 1 Ib. = 29-896259 cub. in., or -0174 cub. ft. The equivalent of 1 ton of ice is 318,080 thermal units,* that is to say, that this is the amount of heat that would be required to convert 1 ton of ice at a temperature of 32 Fahr. into 1 ton of water at a temperature of 32 Fahr. ; or, on the other hand, it is the amount of heat that is necessary to extract from 1 ton of water at a temperature of 32 Fahr. in order to convert it into 1 ton of ice at a temperature of 32 Fahr. The amount of heat that would have to be abstracted from 1 ton of water at 60 Fahr. to form 1 ton of ice at 32 is 382,144 units. When the manufacture of artificial ice first assumed the proportions of an industry no great thought was given to the quality of the pro- duct, and consequently all, or the greater part, of the ice so made was opaque. Soon, however, a demand for a superior article arose, and it became necessary to introduce means for the production of clear, transparent, crystal ice ; the result being numerous inventions and patented devices of more or less efficacy. The reason why the blocks of ordinary artificial ice are formed opaque is that the rapidity of the freezing process prevents the air contained in solution in the water from escaping, and this opacity in- * A thermal unit is that amount of heat necessary to raise the temperature of 1 lb. of water 1 by the Fahrenheit scale when at 39 '4. Mech. eq., 778 pounds. 484 ICE-MAKING. 485 creases towards the centres of the blocks, and is less in hot climates than in colder ones because the quantity of air held in the water decreases as its temperature is raised. Not only is this opacity objec- tionable by reason of the less pleasing appearance of the ice, but also on account of the far inferior keeping qualities of the article. VARIOUS METHODS OF ICE-MAKING. Five methods may be employed for preventing this opacity and forming clear, transparent, crystal ice, viz., by freezing the water slowly at comparatively high temperatures ; by agitating the water in cans, moulds, or cases during the process of freezing, so as to admit of the escape of the contained or imprisoned air ; by forming thin slabs of ice on what is known as the wall or plate system ; by freezing water in shallow stationary cells ; and finally by de-aerating or depriving the water of its air before placing it in the moulds or cells. The first of these plans, besides, at best, only producing blocks of ice partially clear, was so extremely slow, and required the use of such a large number of cans or moulds, and correspondingly large tanks, as to thereby render the first cost of the apparatus ruinously high, and it was consequently soon abandoned altogether; a modification of the same method wherein the temperature of the liquid or medium used for abstracting the heat from and freezing the water was gradually decreased, having likewise experienced the same fate. The second method or agitation can be more or less successfully carried out in a number of different ways, but has, likewise, certain drawbacks ; for instance, complication of mechanism, increased first cost of plant, &c. IP- The third and fourth methods, or the wall or plate and shallow stationary cell systems are also objectionable, by reason of the extent of the plant required and the slowness of the process. The fifth method, or that wherein the water is first de-aerated, that is to say, the air is expelled from the water before it is placed in the cans, moulds, or cases, is, all things considered, perhaps the most satisfactory, and is in extensive use in many works where large quantities of ice are made. As the refrigeration of cold stores or chambers, so also the manu- facture of ice with modern machines may be divided into two main systems, that is to say, the one wherein brine previously reduced in temperature in the cooler or refrigerator of the machine is used for 486 REFRIGERATION AND COLD STORAGE. freezing the water, and the other wherein the freezing or congelation is effected by the direct expansion of the refrigerating agent. It will be readily seen that the latter system enables a very considerable amount of apparatus, essential in the first, to be entirely dispensed with ; prevents the loss of efficiency due to a second trans- mission of heat ; and, moreover, avoids the mess and inconvenience so frequently occasioned by a careless or unskilful use of the brine solution. Much greater difficulties, however, have to be surmounted before the direct-expansion system can be successfully applied to ice-making than is the case with the cooling or refrigerating of cold stores or chambers. In the latter, indeed, all that is required to ensure com- plete success is a perfectly gas-tight system of pipes, and as a pipe of no very great diameter forms the safest, surest, and least expensive method of imprisoning or confining a gas of a searching nature, it con- sequently follows that no insurmountable difficulty is here experienced. But the freezing or congelation of water is quite another matter, and requires straight surfaces, as it is not only very difficult to remove the ice that becomes formed round pipes, but a very considerable portion of it is also wasted in so doing. Hitherto attempts to construct straight surfaces with sufficiently gas-tight joints have proved more or less a failure. Amongst the numerous different methods devised for agitating the water whilst it is freezing, mention may be made of the following : The insertion into the can or case of a metal or other bar which has imparted to it a* vertical reciprocating motion through a revolving shaft and cam or wiper, or by a crank on the shaft, or the placing in the can or case of a wooden or other paddle which is moved to and fro, or of an endless screw or spiral which is rotated by any suitable mechanism. The introduction into the can or case of a pipe extending to within a short distance of the bottom thereof, and through which a current of cold air is forced, which rising in bubbles through the water, produces a circulation in the latter. The imparting of a rocking or oscillating motion to the can or case itself during the freezing operation. The main objection to those arrangements wherein some form of agitator, or the above mentioned air tube, is inserted into the can or case is the necessity for withdrawing them, at or near the termination of the freezing operation, to prevent them from being frozen into the blocks of ice. In the last-named method, the gear for imparting motion to a large number of cans or cases is found to be exceedingly cumbersome, and ICE-MAKING. 487 has besides to be disconnected, to allow of their being lifted from the ice-making tank or cistern to remove the finished blocks of ice from the cans. THE CAN SYSTEM. Fig. 343 shows a patented arrangement of Pontifex and Wood's for making clear or transparent pyramids of ice suitable for table decoration, Ac. -The ice-making box or tank A is formed of iron, wood-lagged, and the intervening space is filled with sawdust. The ice-moulds or cases B are made of galvanised wrought-iron, and are of a suitable pyramidical form ; and the agitators c consist of spirals or endless screws, which are kept constantly revolving, during the freezing of the block, by gut or other bands D, gearing on pulleys E, fixed upon the vertical spindles carrying the spirals or endless screws, and upon a horizontal shaft F, supported in bearings in brackets secured to the side of the tank, to which latter shaft rotary motion is imparted through belt gearing from any avail- able source of power, as shown in the drawing. When the block is nearly frozen solid the agitators must be withdrawn, for which pur- pose the brackets carrying the spiral, or endless screws, are so secured to the tank as to be readily removable therefrom. Fig. 343. Pyramid By arresting the freezing action before the Ice-making Box or Tank, block is frozen quite solid the central hollow Vertical Section. can be filled up with fruit, flowers, or other objects, and afterwards the congelation completed, thus producing very beautiful effects. Fig. 344 is a perspective view showing a can ice-box with agitators, which is the oldest and simplest method of making clear or crystal ice. The construction of the apparatus, which is of the Pontifex- Wood improved type, will be apparent from the drawing. The agitators c, which are very readily removable, are operated through rods running upon rollers, to which rods a reciprocating motion is imparted from a rocking shaft G, mounted at one end of the tank, through suitable connecting rods. The ice-making tank A is similar in construction to that shown in Fig. 343, but is of larger dimensions, and is filled with brine, a circulation of which is kept up from the coils of pipes in the cooler of the refrigerating machine by a brine-pump, in 488 REFRIGERATION AND COLD STORAGE. the usual manner. The ice-cans or moulds B are formed of galvanised iron, and the blades of the agitators c are of wood. To remove the finished blocks of ice from the moulds or cans they are dipped for a few seconds in a tank containing warm water, which may be derived from that running to waste from any convenient source. The sizes of the blocks of ice made vary from 2 ft. x 2 ft. x 6 in. in thickness up to 3 ft. 6 in. x 3 ft. 6 in. x 12 in. in thickness, and in weight from 1 cwt. up to 6 cwt., according to the dimensions of the cans employed. Fig. 345 is a vertical longitudinal section showing the " Eclipse " can ice-box made by the Frick Co. The interior arrangement of the trunk and ammonia evaporating pipes or coils, ice-moulds or cans, B Fig. 344. Box or Tank for Making Ice on the Can System. frame-work for holding the cans in position, with the wooden covers, are all clearly shown in the engraving. Puplett's agitators for liberating the air from the water during freezing are also reciprocated by crank mechanism. They are, more- over, so arranged that as the ice grows, and it becomes necessary or desirable to reduce the width of the paddles or agitator blades, the latter can be feathered by giving them a quarter-turn in + shaped slots. This system of making clear, crystal, transparent ice has, as already stated, several objectionable features, which may shortly be summed up as follows : The blades of the agitators occupying the centres of the cans or moulds whilst the blocks are freezing, have to be withdrawn at the ICE-MAKING. 489 finish, in order to prevent their becoming frozen into the blocks, conse- quently the spaces occupied by them during their traverse have to be congealed without agitation, with the result that each block has a narrow core of semi-transparent or almost opaque ice in the centre, which to a slight degree, spoils its appearance, although the keeping qualities of the ice are not affected thereby. If, however, any im- purities are contained in the water they become frozen up in the blocks and show through them, to the considerable detriment of their appearance. The unavoidable freezing of the blocks at different speeds frequently results, with careless watching, in some of the agitator blades or paddles Fig. 345. " Eclipse" Can Ice-making Box. Vertical Longitudinal Section. getting frozen in prematurely, and broken off. The cans or moulds are sometimes filled too full of water, which, in consequence of the expansion due to freezing, runs over into the brine solution and dilutes it, in some cases to such an extent as to cause it to freeze or congeal at the ordinary working temperature of the machine. The additional weight of the cans or moulds which have to be lifted with the blocks of ice entails an extra expenditure of labour, and the constant handling thereof renders their lives short and necessitates a large stock and frequent repairs and renewals. To obviate the first of these objections, wooden frames have been sometimes placed in the centres of the moulds or cans, inside which the agitators are adapted to work, a block of ice being frozen 490 REFRIGERATION AND COLD STORAGE. up at each end. This, however, gives rise to further serious objections, the wooden frames having to be removed from the moulds or cans with the ice blocks, detached therefrom by means of chisels, and again replaced in the moulds, and a certain quantity of dirty water has moreover to be pumped out of each of the latter before the with- drawal of the ice block and frame therefrom, both of which operations entail much additional labour. The unequal rate of freezing of the blocks causes some of them to come out of an uneven shape and under their proper weight owing to the large holes in their centres. Every apparatus for making ice on this system should be fitted with an arrangement for automatically supplying to each can or mould a sufficient predetermined charge, and no more. In the absence of this, however, a gauge should be used, and the greatest care in filling the cans should be exercised. The moulds or cans should not be filled to more than within 6 in. of the top. Fig. 346. Propeller for Circulating or Agitating Brine in Ice- making Tank or Box. Side Elevation. On the other hand, again, the can system has several well-defined advantages which certainly deserve full consideration. For instance, the first cost of the simple apparatus is low as compared to many others ; the blocks of ice produced being, as a rule, of an uniform given size and weight, the necessity for weighing them is dispensed with and they are very convenient to load and pack ; should a can become leaky it can be placed on one side for repairs and a spare one inserted in its place without delay ; and, lastly, the construction of every part of the apparatus is so simple that it can be made or repaired by any ordinary engineer without special knowledge of ice-making machinery. The cold brine in the ice-making tank or box is circulated or agitated by means of a duplex, centrifugal, or other suitable pump, or by means of a propeller. The latter, one form of which, made by the "Triumph" Machine Company, is shown in Fig. 346, is the cheapest arrangement, and is sufficiently effective. The shaft of the above propeller is made of the best bronze metal, with three bearings ICE-MAKING. 491 fitted with ring oilers. The bearings are of double-brace make. This propeller may be operated by belt-gearing from a small engine, or by an electric motor, or any other available source of power. Fig. 347 is a brine strainer of a pattern made by the Frick Company, and the construction of which is obvious from the drawing, which shows it in vertical central section. Many ingenious, but mostly complicated and expensive, mechanical arrangements have been also devised for facilitating the handling of the cans or moulds, and so lessening the labour of moving them, a brief description of some of the best and simplest of which will be found at the end of this chapter. The Freezing Time Required for Can Ice. With brine at 14 Fig. 347. Brine Strainer, Frick Pattern. Vertical Central Section. the average time of freezing different-sized blocks of can ice is, according to Mr F. E. Matthews writing in Power, New York, as shown in the following table : TIME REQUIRED FOR FREEZING CAN ICE. Size of Can. Weight " ]~ _T 1 ^ PUMP ROOM L "-"N *. V Figs. 378 to 380. Frick Company Arrangement for Ice Factory of 100 Tons Capacity. Plan and Sectional Side and End Elevations. slightly above the centre of gravity of the cans or moulds. At one end of each of these frames a quadrant, worm and worm-wheel, or some other convenient means are provided for enabling the frame and moulds therein to be inclined to any required angle. To admit of the frames being raised from the ice-making tank or box by the overhead 524 REFRIGERATION AND COLD STORAGE. traveller the latter is fitted with links adapted to engage with the above mentioned trunnions or gudgeons. The frame and moulds or cans being nearly balanced on their trunnions, the labour of discharg- ing the ice therefrom is great! y reduced, and the operation is moreover considerably expedited. The quadrant or worm gearing is usually ICE-MAKING. 525 so arranged as to engage with a suitable device fixed on to the links of the overhead traveller ; but mechanical contrivances can be dispensed with and the frame containing the moulds tipped by hand, which operation, owing, as above-mentioned, to its being almost balanced, can be so accomplished without any difficulty. Fig. 386 is a truck ice-can hoist tor use with very small ice-making plants. Fig. 387 is a travelling crane, and geared hand-power ice-can Figs. 383 and 384. Vulcan Iron Works Arrangement for a 5-ton Ice Factory Flan and Sectional Elevation. hoist by means of which one man whilst on watch can take care of from ten to fifteen cans per hour. And Fig. 388 is an electric crane for use in connection with large installations, and which is capable of lumHliTig any desired number of cans. The above appliance is constructed by the Frick Company. JSg. 389 represents an automatic ice-dump made by the Triumph Ice Machine Co. The box is made of ^-in. steel, reinforced by 526 REFRIGERATION AND COLD STORAGE. ICE-MAKING. 527 | in. by J in. iron. The valve and shaft are bolted on this box with a heavy flange. The stands carry the bearings and box, and are bolted to a cast-iron waste box, there being no wood about the box to decay or give way. The operation of this dump is as follows, viz. : The box being in a vertical position to receive the can, the small lever at the bottom can be operated by the foot so as to give the dump a slight tilt toward the front, when the dump will go over slowly and turn on the warm water automatically, while same is turning down in position to dump the ice. The water strikes all sides and under the can. The valves are so regulated that the bottom of the can will receive the most water, thereby melting the ice away from that part. The weight of the ice starting, the cake will then fall on the bottom of the can, and the air will rush in over the top of the ice, forcing same out of the can. Fig. 390 shows the Vulcan Iron Works track system. The rail in this arrangement is supported during the throw of the switches, so that no abnormal strain can come upon the hinge or joint, and the latter cannot be broken off if the switch be left open. The rail is formed of 2J in. by \ in. iron, and the hangers are so constructed that any portion of the rail can be secured to the hanger without drilling. These switches are made two, three, and four throw. Ice-delivery machines and other labour-saving appliances are also manufactured by the Pulsometer Engineering Co., Ltd., and others. Whatever the arrangement, however, for drawing the ice, one thing is absolutely necessary to ensure economical working, and that is the strictest regularity. It is, of course, understood that the machinery should also be kept working at as uniform a speed as possible, and that all temperatures should be maintained as normal as practicable. Suitable ice elevators or hoists are also required for raising the blocks of ice from one level of the factory to another. Amongst numerous devices for this purpose, mention may be made of the Fig. 386. Frick Ice-Can Hoist for use with Small Ice-making Plants. 528 REFRIGERATION AND COLD STORAGE. Fig. 387. Travelling Crane and Geared Hand -power Ice-Can Hoist. Fig. 388. Electric Crane for Handling Ice Cans in Large Factories. ICE-MAKING. 529 following, viz., that wherein an endless chain, provided with hooks, is employed to grab the blocks of ice, and drag them up an incline, which latter may be made in sections, so as to admit of the ice being dis- charged at different elevations. The hooks are set in position to engage with the blocks of ice by a spring bar upon the frame carry- ing the driving-wheel. In another arrange- ment the blocks of ice are shoved up a fixed spiral incline, by arms or levers projecting radially from a shaft, located vertically in the centre of the in- Fig. 389. Automatic Ice Dump. cline, and rotated in any convenient manner. Ordinary hydraulic or steam platform lifts, communicating between the different floors of the factory, may be located wherever found to be Fig. 390 Vulcan Iron Works Track System. necessary and convenient, as also run-ways or slip-ways and gravity hoists. A number of loose tools are likewise required in an ice factory for manipulating the ice, such as ice-saws, hatchets, hooks and picks hoisting tongs, trollies, &c. 34 530 REFRIGERATION AND COLD STORAGE. ICE-MAKING, GENERAL. Cube Ice. An arrangement invented by Mr Van der Weyde for cutting ice into small blocks or cubes comprises circular saws and endless conveying bands or belts, by means of which the cut blocks or cubes are delivered to a special packing table, where they are stowed in boxes for delivery. It is advisable to have hydrants in suitable positions throughout the buildings, and this precaution is especially desirable where ammonia machines are in use, the extreme affinity of ammonia for water render ing the latter (as already mentioned) the best remedy to employ for killing the ammonia should any considerable quantity become accidentally spilt. The ice store is usually refrigerated by means of a brine or direct expansion coil, and the ante-room thereto should be cooled in a similar manner. It may be taken that, as usually stored, a ton of ice will occupy about 50 cub. ft. The top layer should be covered with dry sawdust or shavings. See also " Storing Ice." In some places it is found advisable and advantageous to add to the ice factory buildings one or more cold stores or chambers, wherein perishable products can be preserved for customers desiring such accommodation. The management of ice-making and refrigerating machines will be found dealt with in the next chapter, so far as the space at command will allow. That of the steam engines or other motors employed for driving these and of the miscellaneous accessory machines and apparatus will, of course, in no way differ from those used for other purposes, and instructions for the proper care and working thereof are outside the province of this work.* FREEZING TIMES FOR DIFFERENT TEMPERATURES AND THICKNESSES OF CAN ICE. Siebert. Thickness. 1 in. i 2 in. Sin. 4 in. 5 in. 6 in. 7 in. Sin. 9 in. 10 in. 11 12 in. j Temperature 10 12 0'32 1-28 0-35 I'iO 2'86 315 510 6-60 8 8-75 11-5 12-6 15-8 17-3 20-4 22-4 25-8 28'4 31-8 35 38-5 42-3 45-8 60 14 0.39 1-66 3'50 6-22 970 14 19 25 31-5 39 47'0 56 16 0'44 176 3-94 7 11 15'8 21-5 28 35-5 437 53-0 63 18 0'60 2 4 '50 8 12-5 18 24-5 32 40-5 50 60-5 72 20 0-57 2-32 5'25 9-30 14-6 21 28-5 37-3 47-2 583 70-5 84 22 0-70 2-80 6-30 11-2 17-6 25-2 34-3 44-8 567 70 847 100 24 0-88 3'50 1 7 '86 14 21 31-5 42'S 66 71 87-5 106 126 * For detailed information regarding friction and the management and lubrication of the rubbing parts of machinery see " Bearings and Lubrication," by the same author. ICE-MAKING. TIME REQUIRED FOR WATER TO FREEZE IN ICE CANS. (The Triumph Ice Machine Co. Catalogue}. Size of Cans. Weight of Cake. Time to Freeze. 6 in. by 12 in. by 24 in. 50 Ibs. 20 hours 8 , 18 32 , 100 36 8 , 16 40 , 150 ,, 36 11 , 22 32 , 200 55 11 , 22 44 , 300 ., 60 11 , 22 57 , 400 60 NOTE. Temperature of bath 14 to 18 Fahr. As a rule, the higher the bath temperature the slower the process of freezing, but the finer and clearer the ice. TABLE OF ICE-PLANT EFFICIENCIES COLLECTED FROM TWENTY-SEVEN EXISTING AND OPERATING PLANTS. Sneddon. Lbs. of Water Lbs. of Total Ice Pro- duced in Tons per 21 hours. Coal Con- sumed in Ibs. per 24 Hours. Evaporated to loo Ibs. G Pressure from 212 per 24 Hours Water Evaporated per Ib. cf Coal (or Ibs. of Ice B.T.U. con- tained in 1 Ib. of Coal (Calcu- lated). Heat put into Total Water Evaporated by 1 Ib. of Efficiency per Cent. 1 Loss on 70 per Cent. Basis per Cent. (or Max. Ice Made). Coal. i Production). 5'4 4,800 10,800 2-25 13,400 2,261 17-6 75 57 4,800 11,400 2-37 13,400 2,381 17-7 74-8 7-25 4,000 14,500 3-62 12,200 3,638 29-8 57-5 7-5 4,000 15,000 3-75 12,200 3,768 30-8 56 10-33 5,000 20,660 4-13 14,858 4,150 27'9 60-2 11 5,000 22,000 3-93 14,858 3,949 , 19-9 71-6 14 12,000 28,000 2-33 12,700 2,341 18-4 74-3 14-o 9,000 29,000 3-22 11,900 3,236 27-2 61-2 16-5 9,500 33,000 3-47 11,900 3,488 29-3 58 15'6 9,600 31,200 3-25 12,300 3,266 26-5 62-2 16-5 11,200 33,000 2-94 12,300 2,945 24 65-8 20 12,000 40,000 3-33 12,600 3,346 26-5 62-2 19 8,000 38,000 475 12,200 4,773 39-1 44-2 14-5 6,000 29,000 4-83 12,200 4,854 39-8 43-2 17-5 10,000 35,000 3-5 12,000 3,517 29-3 58 17'66 10,000 35,320 3-53 12,600 3,547 28-1 60 27-5 13,500 55,000 4-07 13,000 4,090 31-3 55-3 19 7,000 38,000 5-42 12,200 5,447 44-6 36-3 20 6,000 40,000 6-66 13,000 6,693 51-4 26-6 23 6,800 46,000 6-76 13,000 6,793 52-2 25-5 24 7,000 48,000 6-85 13,000 6,884 53 25-8 29 14,000 58,000 4-14 12,000 4,160 34-6 50-6 25 18,000 50,000 2-77 12,000 2,783 23-2 66-9 32 22,000 64,000 2-90 12,000 3,045 25-3 62-9 31 14,000 62,000 4-42 i 10,500 4,442 42-2 39-8 82 22,500 164,000 7-28 13,100 7,286 55-6 20-6 85 20,740 170,000 8-22 13,100 8,261 63-0 10 532 REFRIGERATION AND COLD STORAGE. TABLE GIVING SIZES AND CAPACITIES OF VARIOUS ICE-MAKING PLANTS. H. H, Kelly, " The Engineer? New York. Tons* per Twenty four Hours. Size of Engine. Revolu- tions. Size of Com- pressor. Size of Blocks of Ice. Gallons of Water per Hour. Tons of Coal. u- S2 o B fc H sg o| *! No. of Labourers. 1 7 by 9 90 t5 by 10 8 by 8 by 28 5 \ 1 _ 3 8 16 80 5 ,, 15 8 15 28 15 1 2 2 2 5 10 20 75 6 18 11 15 28 20 1ft 2 2 2 10 12 ,, 30 70 8 20J 11 22 28 11 11 28 }30 2 2 2 3 10J 14 30 65 8 25J 11 22 28 11 11 28 }35 2i 2 2 3 15 14 ,, 30 65 10 20J 11 22 28 11 11 28 }40 3 2 2 4 20 16 30 55 10 30{ 11 22 28 11 11 28 J50 4 2 2 5 30 16 42 52 11 30J 11 22 28 11 11 28 }eo 5 2 2 6 40 18 36 50 12 ., 30 11 11 28 90 6ft 2 2 7 45 20 36 50 15 30 11 11 28 94 8 2 2 8 60 24 36 45 16 36 11 11 28 96 10 2 2 9 80 26 48 45 20 36 11 22 28 100 14 2 2 10 2,000 Ibs. f One cylinder. BRINE FOR USE IN REFRIGERATING AND ICE-MAKING PLANTS. A brine suitable for the above purpose can be made with from 3 to 5 Ibs. of chloride of calcium, or muriate of lime, in accordance with its degree of purity, dissolved in each gallon of water. The density of this solution is about 23 Beaume, its weight about 13^ Ibs. per gallon, and the freezing point is - 9 Fahr. As the above standard of density must be kept up, in order to prevent the brine from becoming congealed in the refrigerator or the ice-making tanks or boxes, it is desirable to test it periodically with a salinometer. In the best American practice first quality medium-ground salt, preferably in bags for convenience of handling, is employed, the proportions being about 3 Ibs. of salt to each gallon of water. The brine is made in a brine mixer, such as that shown in Fig. 391, which consists of a water-tight box or tank A, about 4 ft. by 8 ft. by 2 ft., having a suitably perforated false bottom B, and a small compartment c, partitioned off at one extremity, communicating with the main compartment through an overflow D } situated at the upper end of the partition, and fitted with a large strainer to prevent the passage into ICE-MAKING. 533 the small compartment of salt or foreign bodies. The water is admitted through a pipe E, which extends into the tank A, and runs the full length of the false bottom, the latter portion being perforated, as shown, and the brine is removed through a pipe F from the upper part of the end compartment, at the lower extremity of which latter pipe is a strainer-box and strainer through which the brine passes before delivery into the brine-tank. A salt gauge, salinometer, or hydrometer is also placed in this end compartment. The sketch shown is from one given in the New York Engineer. The salt should be dissolved in the water until it reaches a density of about 90 by the hydrometer. To facilitate dissolution it is desir- able to stir the salt in the mixer with some handy implement, the salt being shovelled in as fast as it can be got to dissolve. By the use of this mixer the settlement of salt on the bottom and B Fio. 391. Brine Mixing Tank. Vertical Longitudinal Central Section. on the coils in the brine tank, which inevitably results when the solution is effected directly in the latter, is avoided. To maintain the strength of the brine it is recommended to suspend bags filled with salt in the brine-tank, or to pass the return brine through the above-described brine maker or mixer. A cheap and easily constructed apparatus for mixing brine can be made out of an old barrel in which a perforated false bottom is fixed a short distance above the bottom, the water to form the solution being delivered to the space between the two bottoms, and an overflow pipe, fitted with a suitable strainer and a well to receive a salinometer, being provided near the top to draw off the brine. When the temperature falls below 7 below zero Fahr. chloride of calcium must be employed, as a solution of common salt can only be reduced to a temperature 7 below zero, whilst chloride of calcium can be cooled down to 39 below zero Fahr. 534 REFRIGERATION AND COLD STORAGE. Fig. 392 illustrates a brine concentrator of the Haslam type. The apparatus comprises a steam -jacketed pan, known as the concentrator, a series of tubes known as the interchanger, and a brine pump. The operation of the apparatus is as follows : Brine is drawn from the battery by the pump, forced through the interchanger, and delivered Fig. 392. Haslam Brine Concentrator. into the concentrator. Here it is reduced by heat to the right specific gravity, after which it is allowed to flow back over the interchanger into the battery. In passing over the interchanger, it is cooled by the incoming brine flowing through the interchanger, and in turn heats the incoming brine, thus saving both steam and work on the refrigerating machine. ICE-MAKING. 535 STORING, HANDLING, AND SELLING ICE. For storing purposes ice should be clear, solid, and devoid of core. In America some persons insist that ice for storage should not be made at temperatures higher than 10 to 14 in brine-tank. The first requisite for a storage house for artificial ice, as also for natural ice, is, of course, the best possible insulation ; other necessary points to be attended to are drainage and ventilation. The best shape for an ice-storage house is square, or as nearly approaching this form as possible, and the roof should have a good pitch. An ante-room or lobby is also desirable, as by the provision of this latter the necessity for the frequent opening of the main store is done away with. To preserve the ice, the storage rooms, as well as the ante-chambers or lobbies must be refrigerated, and the amount of the latter required may be roughly estimated, according to Prof. Siebel, at from about 10 to 16 British thermal units of refrigeration per cubic feet contents for twenty-four hours. About 1 ft. of 2-in. pipe (or its equivalent in other size pipe) per 14 to 20 cub. ft. of space is frequently allowed, says the same gentleman, in ice-storage houses for direct expansion, and about one-half to one-third more for brine circulation. The pipes should be located on the ceiling of the ice-storage house. The ventilation of an ice-storage house should be carefully attended to, and ventilators fitted with suitable regulators should be provided both in the highest part of the roof and also in the gable ends. The drainage should be such as to absolutely prevent the accumulation of any moisture beneath the bed of ice. It is recommended to paint an ice store white, preferably with a mineral such as barytes or patent white. Respecting the best method to adopt for packing the ice in the store considerable diversity of opinion seems to exist. It is well to provide a bed of from 18 in. to 2 ft. of cinders, as this tends to improve the drainage of the house. In one method the blocks are placed on edge and as closely packed together as possible, the blocks in each succeeding layer being placed exactly over those beneath and all breaking of joints being avoided. The ice is covered between the times of storing with dry sawdust or soft wood shavings, and the uppermost layer is invariably covered with dry sawdust or shavings. Mr R. Thompson, writing to the Canadian Farming World, says that in filling the house he places the ice on edge, placing every alternate layer crossways, which plan, he claims, enables ice to keep better and come out easier. 536 REFRIGERATION AND COLD STORAGE. Others recommend that the ice be stored with alternate ends touching and alternately from 1 J to 2 in. apart, so as to prevent the ice from freezing together. The cakes or slabs of ice should not be parallel to each other, and storage should only be made when the temperature is at or below freezing. Or, again, J-in. strips placed between the layers of ice in the store so as to separate the cakes or blocks, top, side, and bottom, from all others in the house. For packing the ice, sawdust, rice chaff, straw, hay marsh or prairie hay being said to be preferable are employed. Of these materials hay is the best, rice chaff is capable of being dried and re-used. 6 in. of well-packed hay should be placed between the ice and the walls, and no covering until the store is full. 1 cub. ft. of ice is taken to weigh 57*5 Ibs. approximately at 32 Fahr. 1 cub. ft. of water frozen at 32 will make 1*0855 cub. ft, of ice, thus showing an expansion of 8-5 per cent, due to freezing. 1 cub. ft. of pure water at 39 Fahr., its point of greatest density, weighs 62 '43 Ibs. 50 cub. ft. of ice, as usually stored, equals about 1 American or short ton of ice (2,000 Ibs.), or 62 cub. ft., 1 English ton. In small ice houses in which the ice is closely packed, a short ton of ice can be got into from 40 to 45 cub. ft. When withdrawing ice from a store breaking-out bars for bottom and side breaking are required, and if properly skilled assistance is not available a considerable amount of the ice will in all probability be broken up and wasted. The wastage of ice in an ice store not artificially cooled, from January to July is, in the United States, at the rate of about ! Ib. of ice per twenty-four hours for each square foot of wall surface, or say from 5 to 10 per cent, of the ice stored during the six months. The amount of heat that will pass through 1 sq. ft. of ice 1 in. in thickness is put at 10 British thermal units per hour for each degree Fahrenheit difference between the respective temperatures on each side of the sheet of ice. In handling and selling ice, the waggons should be clean and sanitary, the men in charge should avoid walking about in them with dirty boots, and blocks of ice should not be deposited and slid about on filthy pavements. These matters are attended to in the United States, but here they are totally neglected. In the United States the selling and delivery of ice is generally done by the coupon system, which is thus described by Prof. Siebel : " It is a system of keeping an accurate account with each customer of the de- livery of and the payment for ice by means of a small book containing ICE-MAKING. 537 coupons, which in the aggregate equal 500 or 1,000 or more pounds of ice taken by the customer every time ice is delivered. These books are used in the delivery of ice in like manner as mileage books or tickets are used on the railroad. A certain number of coupons are printed on each page, each coupon being separated from the others by perforation, so that they are easily detached and taken up by the driver when ice is delivered. Such books are each supplied with a receipt or due bill, so that if the customer purchases his ice on credit, all that is necessary for the dealer to do is to have the customer sign the receipt or due bill and hand him the book containing coupons equal in the aggregate to the number of pounds of ice set forth in the receipt or due bill. The dealer then has the receipt or due bill, and the customer has the book of coupons. The only entry which the dealer has to enter against such purchaser in his books is to charge him with coupon book number, as per number on book, to the amount of 500, 1,000, or more pounds of ice, as the value of the book so delivered may be. The driver then takes up the coupons as he delivers the ice from day to day." ICE-CRUSHING OR BREAKING MACHINERY. A class of machine required in most modern ice factories is that for ice-crushing or breaking. There are numerous uses for this type of machine, but probably the most important is the crushing of ice for use on board fishing smacks and vessels, where it would be compara- tively useless in large solid blocks, and must be crushed or broken up into small pieces before it can be satisfactorily employed for the purpose of packing the fish. This latter desideratum likewise applies to the transport of fish by rail, and to the requirements of fishmongers, hotels, restaurants, &c. Fig. 393 shows a belt-driven machine having a crushing capacity of 15 tons per hour, built by Messrs David Bridge & Co., Castle ton, Manchester, a firm that have made a speciality of this class of machinery. The machine consists essentially of a suitable hopper to receive the blocks or pieces of ice, and a pair of crushing or breaking rollers provided with steel spikes arranged in such a manner that the ice will not be allowed to slip or slide, and the breaking operation will consequently commence without loss of time. The breaking or crushing rollers are suitably geared, and the bearings are independent, gunmetal bushed, and provided with effective lubricating arrangements. An excellent feature in the design of the machine is that all the parts are so arranged as to be readily accessible for cleaning and repairs. 538 REFRIGERATION AND COLD STORAGE. Besides the machine shown, the firm also make various other sizes of power-driven crushers from 1 J tons up to 30 tons per hour capacity, as well as small hand-power machinery intended for the use of fish- mongers, and in hotels, restaurants, or anywhere, in fact, where it is Fig. 393. 15-Ton per Hour Ice-crushing Machine. required to crush or break ice from the block, but the demand is not large. These latter machines are made in three sizes, viz., of 10, 15, and 25 cwt. capacities. Ice-crushing machines are also made by Mr C. E. Barton, of Grimsby, and others. CHAPTER XX THE MANAGEMENT AND TESTING OF REFRIGE- RATING MACHINERY, ETC. Management Ammonia Compression Machines Oil Separators or Collectors Accumulations of Deposit in the Condenser Breaking Joints Lubricating Qualities of Ammonia Compressor Piston-Rod Packings To Charge and Work a Carbonic Acid Machine Freezing or Choking up of Compression System Lubrication of Refrigerating Machinery Leaks in Ammonia Ap- paratus Leaks in Carbonic Acid Machines Effect of a Coating of Ice on Direct-Expansion Pipes Defrosting Refrigerating Coils Incrustation on Condenser Coils Cold- Air Machines Testing Interpretation of Compressor Diagrams Absorption Machines Amount of Water required in Refrigerat- ing Apparatus Determination of Moisture in Air Psychrometers Hygro- metersElectrical Temperature Tell-Tales and Long-Distance Thermometers The Thermograph The Telethermometer or Electrical Thermometer Lighting Cold Stores. MANAGEMENT. AMMONIA COMPRESSION MACHINES. EVERY particular type of machine working on this principle has, as a rule, certain distinctive or characteristic features, and will, of course, so far at least as these are concerned, require special care and adjust- ment, and it would consequently be totally impossible to lay down an arbitrary set of rules for working that would be suitable to all ; nor is this necessary or required, as full particulars relating to the manipula- tion of each particular machine are invariably supplied by the makers. The following points, however, are more or less applicable to all machines working on the ammonia compression principle, and should therefore be familiar to those in charge of same. Before charging an empty machine with anhydrous ammonia, all air must first be carefully expelled. This is effected by working the pumps so as to discharge the air through special valves which are usually provided on the pump dome for that purpose. The entire system should have been previously to this thoroughly tested by working the compressor, and permitting air to enter at the 539 540 REFRIGERATION AND COLD STORAGE. suction through the special valves provided for that purpose, and it should be perfectly tight at 300 Ibs. air pressure on the square inch, and should be able to hold that pressure without loss. Whilst testing the system under air pressure it should be also carefully blown through and thoroughly cleansed from all dirt, every trace of moisture being likewise removed. It is totally impossible to eject all air from the plant by means of the compressor, therefore it is advisable to insert the requisite charge of ammonia gradually and not all at once, the best practice being to put in from 60 to 70 per cent, of the full charge at first, and cautiously permit the air still remaining to escape through the purging-cocks with as little loss of gas as possible, subsequently inserting an addi- tional quantity of ammonia once or twice a day, until all the air has been got rid of by displacement, and the complete charge has been introduced. To charge the machine, the drier or dehydrator of the apparatus for manufacturing or generating anhydrous ammonia, or, where no such apparatus is included in the installation, the drum or iron steel flask of anhydrous ammonia, should be connected, through a suitable pipe to the charging valve ; the expansion valve must be then closed, and the valve communicating with the drier or dehydrator, or that in the flask or bottle, opened. The machine should be run at a slow speed when sucking ammonia from the drier, or whilst the flask is being emptied, with the discharge and suction valves full open. In the latter case, when one of the flasks or bottles has been completely emptied it must be removed, the charging valve having been first closed, and another placed in position, until the machine is sufficiently charged to work, when the charging valve should be finally closed, and the main expansion valve opened and regulated. A glass gauge upon the liquid receiver will show when the latter is partially filled, and the pressure gauges, and the gradual cooling of the brine in the refrigerator (in the case of a brine circulation or ice-making apparatus) and the expansion pipe leading to the refrigerator coils becoming covered with frost, indicate when a sufficient amount to start working has been inserted. It is sometimes advisable to slightly warm the vessels or bottles containing the anhydrous ammonia by means of a gas jet, or in some other convenient manner, whilst transferring their contents to the machine, as otherwise if frost forms on the exterior of the bottles they will not be completely discharged, and loss of ammonia will ensue. The flasks, bottles, or other receptacles containing the anhydrous MANAGEMENT & TESTING OF MACHINERY. 541 ammonia should be always kept in a tolerably cool and a perfectly safe situation, and they should moreover be moved and handled with the utmost caution and care. In the event of an accident occurring and any considerable quan- tity of the ammonia becoming spilt, it is well to remember that it is so extremely soluble in water that 1 part of the latter at a temperature of 60 Fahr. will absorb some 800 parts of the ammonia gas, therefore water should be employed to kill or neutralise it, and any person attempting to penetrate an atmosphere saturated with this gas should not fail to place a cloth well saturated with water over his nose and mouth, or better still, a suitable helmet or respirator. The machine having been started, and the regulating valve opened, it is essential to note carefully the temperature of the delivery pipe on the compressor, and if it shows a tendency to heat, then the regulating valve must be opened wider ; whilst, on the contrary, should it become cold, the valve must be slightly closed, the regulation or adjustment thereof being continued until the normal temperature of the above pipe is the same as that of the cooling water leaving the condenser. When the charge of ammonia in the machine is insufficient, the delivery pipe will become heated, and that even when the regulating valve is wide open. There are many additional signs of the healthy working of the apparatus other than the fact that it is satisfactorily performing its proper refrigerating duty, which soon becomes easily recognisable to those in charge. For example, every stroke of the piston will be clearly marked by a corresponding vibration of the pointer or indexes of the pressure and vacuum gauges. The frost visible on the exterior of the ammonia pipe leading to and from the refrigerator will be about the same. The liquid ammonia can be distinctly heard passing in a con- tinuous and uninterrupted stream through the regulating valve. The temperature of the condenser will be about 15 higher than that of the cooling water running from the overflow. And, finally, the temperature of the refrigerator will be about 15 lower than the actual temperature of the brine or water being cooled. Air will find its way into the system through leaky stuffing boxes, improper regulation of the expansion valve, &c. Its presence in any considerable volume is shown by a kind of whistling noise, the liquid ammonia passing through the expansion valve in an intermittent manner, a rise of pressure in the condenser, and also loss of efficiency thereof, and other obvious signs. In this case the air must be got rid of through the purging-cocks in a similar manner to that which remains in the system when first charging the machine. 542 REFRIGERATION AND COLD STORAGE. The presence of any considerable amount of oil or water in the system, which may result from careless distillation, will cause a reduc- tion in efficiency, and will be evidenced by shocks within the compressor cylinder. The temperature can be regulated either by running the machine at a higher speed or by increasing the back pressure, or by a combination of both. The back pressure can be regulated by means of an expan- sion valve or valves fitted between the receiver and the refrigerator evaporating coils or pipes in the main liquid pipe. It is absolutely necessary that an ample supply of oil for lubricating purposes be forced into the stuffing box of the compressor at frequent intervals, otherwise it will be found that the heated ammoniacal gas at high pressure will very rapidly cut through even the very best packing. Pure mineral oil of good body is found to be the best lubri- cant ; animal and vegetable oils should not be used, as on contact with ammonia they will saponify, and much trouble and loss will ensue therefrom. Another matter requiring special attention is the proper lift of the suction and discharge valves, and these should invariably be provided with suitable means for admitting of the lift being readily adjusted. The lift should not be too high, otherwise the valves will not close with sufficient promptitude, and a loss of efficiency will result, and that more especially in compressors running at high speed. When superheating of the ammonia gas in the compressor is guarded against by the circulation of cooling water through a jacket surrounding the latter, it is desirable to ascertain the proper amount of water necessary to secure the best results. This will, of course, vary with the condensing pressure ; about 1 '2 gals, of water per hour for each ton of refrigerating effect per day of twenty-four hours being usually found to be sufficient for low condensing pressures of, say, from 95 to 110 Ibs., whilst, on the other hand, with a high condensing pressure of about 150 Ibs. the amount will have to be increased to 50 gals, or more per hour. The larger the amount of cooling water that is employed in the separator jacket the better ; and this water need not be wasted, as it may be conducted through a suitable overflow into the condenser, and utilised together with that delivered specially thereto. The overflow pipe conducting this water to the condenser should preferably dip down for a certain distance into the condenser. Respecting the quantity and temperature of the cooling water for the condenser, it must be remembered the lower the temperature of the MANAGEMENT & TESTING OF MACHINERY. 543 condensed ammonia the less will be the pressure against which the compressor has to work, and consequently the greater will be the saving in fuel and in wear and tear to the moving parts. The amount of condensing water required will vary in accordance with the temperature at which it is run from the condenser. For instance, if the condensing water be run into the condenser at a temperature of about 60 Fahr., and leaves at the overflow or waste at a temperature of, say, 90 Fahr., the quantity of water required will be about 1 gal. per minute for each ice capacity of 1 ton per twenty- four hours ; whilst if the temperature of the overflow or waste were 75 Fahr., the original temperature at the inlet being the same as before, the amount of water required would be about 2*5 gals, per minute for each ice capacity of 1 ton per twenty-four hours, and a reduction of about 40 Ibs. in the condensing pressure would be effected. In large towns and cities, however, where the water from the water companies' mains has to be used, and paid heavily for, it is often doubtful economy to attempt to reduce the temperature of the con- densed ammonia below a certain point, say 60 Fahr., during the winter months, and 70 Fahr. during the summer months. It is obvious that when a high price has to be paid for the water employed for cooling and other purposes, every effort possible should be made to utilise it to the fullest extent, and, with this end in view, it is desirable to use the overflow water from the condenser for boiler-feeding purposes, or to employ some means, such as a cooling tower, for saving that which would be otherwise run to waste and be completely lost. To prevent loss of efficiency from heating of the condensed ammonia, it is advisable that the receiver and piping should be covered with a thick layer of some suitable non-conducting material, which precaution is the more necessary, inasmuch as the piping generally passes through the engine room, and consequently the temperature of the ammonia is not infrequently raised as much as 25 above that at which it left the condenser before it enters the coils or pipes of the refrigerator, which causes a loss of about 2-5 per cent, on the ice- making capacity of the machine. The pipes conveying the ammonia gas from the coils or pipes of the refrigerator to the compressor should be likewise well covered with non-conducting material, so as to pre- vent, as far as possible, any further accession of heat in the gas during the transit. The desirability of this will be readily seen when it is remembered that the refrigerating capacity of a machine of this type is dependent upon the weight of ammonia circulated, and that the volume of a given weight of the gas increases in proportion to the 544 REFRIGERATION AND COLD STORAGE. elevation of its temperature, and consequently the higher this is raised the smaller will be the weight of the gas circulated or dealt with by the compressor, although the volume may be the same. OIL SEPARATORS OR COLLECTORS. In the case of a compressor wherein the cylinder is cooled by a water circulation round its exterior walls, and not by the intro- duction of cooling liquid to the interior thereof, a certain amount of the oil employed for lubricating purposes will gain access to the interior round the piston rod, and this oil would, unless proper means be taken to prevent it, be carried through the discharge valve along with the ammonia gas, and, after first passing into the condenser, would finally gain access to the evaporating or expansion coils or pipes of the refri- gerator, and also stop or clog up the expansion valve, and otherwise reduce the efficiency of the machine. The method employed for recovering any oil carried over with the ammonia gas in a compressor of the De La Vergne type, employing a sealing, cooling, and lubricating liquid in the cylinder, has been already mentioned when dealing with that machine ; with compressors wherein other means are employed for ensuring a complete or a practi- cally complete discharge of the ammonia at each stroke of the piston, suitable oil separatois or collectors for the mechanical separation of the oil from the gas, and in some cases rectifiers are used. The oil separator, which should be at least as large as the liquid-ammonia receiver is, as a rule, placed in the main pipe between the compressor and the condenser. Another oil separator or trap is frequently fitted on the expansion or low-pressure side of the refrigerator, usually in close proximity to the inlet to the compressor pump. The object of this latter is to intercept any scale, dirt, &c., from the pipes, and pre- vent its gaining access to the pump cylinder and injuring the piston and valves. The shells of these separators or traps are usually con- structed of wrought iron or steel, and it is essential to have perfectly gas-tight joints. The separator or oil collector frequently supplied consists merely in a cylindrical vessel into which the ammonia gas is conducted at one extremity and leaves at the other. The inlet and outlet being situated at some inches from the ends or covers, the gas is supposed to be freed from the oil carried over therewith by coming in contact with the sides of the cylinder, and it passes on to the condenser, whilst the oil falls to the bottom of the vessel. MANAGEMENT & TESTING OF MACHINERY. 545 A better form of separator is that wherein baffles or plates, de- scending vertically to slightly below the centre of the cylindrical vessel, and extending alternately nearly but not quite to the opposite sides of it, are employed. In this arrangement the gas is admitted at one side of the cylinder, and, after taking a zigzag course between the baffles or plates, leaves at the other side. A very considerable increase of contact surface is thus ensured in a separator of this type, a modified form of which is employed in the De La Vergne system, and the separator is rendered considerably more efficient. The gas being at a temperature of some 200 Fahr. when passing through the separator or interceptor, the oil contained or carried over with it is in a limpid condition, and is, therefore, difficult to eliminate from the gas. To obviate this objection the separator or oil collector is sometimes water-jacketed, by which means the temperature can be maintained low enough to cause the oil to separate easily from the gas and fall to the bottom of the cylinder or vessel. By this arrangement its efficiency is still further increased. Puplett and Rigg's patent separator or interceptor has been already described in a previous chapter, and centrifugal oil separators have also been used with some success. A type of oil separator recommended by some makers is fitted with an arrangement of wire screens. A separator of this latter type was patented in 1887 by S. Puplett and J. L. Rigg, which consisted of a cylindrical vessel having a water jacket through which a circulation of cooling water is maintained, and provided centrally with two or more sheets or screens of wire gauze or perforated sheet metal, by which the cylindrical vessel or chamber is divided vertically into two compartments. The gas from the com- pression pump is discharged into this vessel or chamber against the sheets or screens, and is forced through the interstices or meshes, the surface contact separating the oil, held in mechanical suspension, from the gas. The separator being maintained at a lower temperature than the gas by means of the above-mentioned water-jacket, a rapid con- densation of any oil passing over with the gas takes place, and this oil is first deposited on the sheets or screens, from which it falls to the bottom of the separator, from whence it can be drawn off through a discharge-cock fixed therein, without stopping the machine, and without any material loss of gas or admission of air occurring. To catch any oil that may pass down the return-liquid pipe, an interceptor is attached to the latter in any convenient position, but preferably as near as possible to the refrigerator. This interceptor is 35 546 REFRIGERATION AND COLD STORAGE. r- E Iff formed of a cylindrical vessel having a diaphragm extending from the cover to within a short distance of the bottom, and another diaphragm extending from the bottom thereof to within a short distance of the cover, thus forming three compartments. The return-liquid pipe passes through the cover nearly, but not quite, to the bottom of the intercep- tor on one side of the first diaphragm that is in the outer compart- ment and is continued from near the bottom of the interceptor to beyond the second diaphragm, that is to say, out of the third compartment. Any oil that passes down the return-liquid pipe collects in the first compart- ment of the interceptor, from whence it can be withdrawn through a cock fixed in the first compartment without stopping the machine, or causing an ap- preciable loss of gas or the admis- sion of air to any injurious extent. This interceptor is preferably jacketed, and is surrounded with, and maintained at a suitable temperature by means of, cold brine, in order to aid in separat- ing the oil from the liquefied gas. Even the best of the ordinary separators or oil collectors at present in common use are, how- ever, more or less defective in action, and those having under their charge expansion coils or -** B Fig. 394. Voorhees Oil Separator or Col lector. Vertical Central Section. brine coolers are well aware of the fact that considerable quan- tities of oil gain access to the expansion coils or the ammonia space of the brine cooler in com- pression systems. This oil, it is well known, is a great drawback to the successful working of the system, acting as an insulator and preventing the efficient transfer of heat from the ammonia to the pipes and also occupying a considerable part of the space required for the liquid ammonia. The oil is in a finely-divided and partially vaporised condition, for which reason the ordinary separators fail to eliminate it MANAGEMENT & TESTING OF MACHINERY. 547 from the liquid ammonia. The obvious remedy seems to be to so construct the separator that the liquid ammonia will be cooled before passing to the expansion valve and so as to condense the oil vapour and separate same from the liquid ammonia. This action would be ensured in the oil separator shown in Fig. 394, designed by Mr Gardner T. Yoorhees, S.B., M.A.S.M.E., which was described in "Ice and Refrigeration." The liquid ammonia from the condenser, after passing through the gas trap, then passes by pipe A into the space, B of the separator. Here the velocity of the liquid ammonia is reduced by the large flow area of the separator. The ammonia flows slowly over the outer surface of the coil c. This coil is as cold as the cold liquid ammonia after it has passed the expansion valve. This cold coil cools the whole body of the liquid ammonia in the separator, and the oil separates out in small globules as shown, and settles to the bottom of the separator. The liquid ammonia, now free from oil, passes out by the pipe D to the expansion valve D*, and expands through the coil c, passing out through the pipe E to the expansion coils, or to the ammonia space in the brine cooler. The oil can be seen in the glass of the automatic gauge-cocks, and can be drawn off from time to time through the pipe F and the valve G. The separator can be insulated or not, as desired. If insulated the only loss of refrigeration would be a neglectable small one through the insulation. If uninsulated, it would be relatively small, and less than is often found in uninsulated liquid headers and expansion valves. Fig. 395 shows a modified arrangement of the catch-alls or inter- ceptors employed on the Yaryan patent evaporators, which could also be used for the elimination of the oil. As will be seen from the illustration it consists in a cylinder A, which is water- jacketed as shown at A 1 , and divided into two compartments by a tube-plate or partition B, from which project tubes c, c, which extend round the gas outlet pipe D, and extend nearly but not quite to the end of the cylinder, the outlet pipe extending into the cylinder for a distance equal to about half the length of the tubes. E is the inlet pipe through which the ammonia gas and the particles of oil carried over therewith are delivered into the first chamber of the separator or oil collector, F is a wire gauze or perforated screen or diaphragm, and F 1 , F 1 are baffle or check plates which extend alternately to within close proximity to the opposite sides of the cylinder. A clearance is likewise provided at the bottom of each of the baffle or check plates F, and of the partition or tube-plate B, to allow of the free passage 548 REFRIGERATION AND COLD STORAGE. of the oil from the first compartment or chamber to a well formed in the bottom of the separator cylinder A ; G is a pipe leading from this well, through which the oil can be drawn off when required ; H, H 1 are respectively the inlet and outlet pipes for the cooling water to the water jacket. In operation the gas and oil enter the first chamber or compart- ment of the separator and pass to the tubes c through the wire gauze diaphragm F, and taking a zigzag course from side to side of the separator past the baffle or check plates r 1 . A large proportion of the oily particles strike against the diaphragm, and the check, division, or baffle-plates F 1 , and become separated from the gas, finally falling to the bottom of the compartment and passing to the well A 2 . The H Fig. 395. Yaryan Form of Oil Separator, Collector, or Interceptor. Vertical Central Section. partially cleared gas then passes through the interior of the open-ended tubes c into the second chamber or compartment, and returns along the space on the outside thereof to the outlet pipe D, the remainder of the oily particles becoming deposited on the interior and exterior surfaces of the tubes c, and on the walls of the compartment, from which they likewise fall, and are collected in the well in the bottom of the latter. The very extended surfaces with which the gas thus comes in contact during its passage through the separator or collector will ensure the complete deposition of the oil held in suspension by the gas, and the latter will finally pass out from the separator or oil collector at the outlet pipe D completely, or practically completely, freed therefrom. MANAGEMENT & TESTING OF MACHINERY. 549 The separator or oil collector is sometimes so connected with the compressor that the oil can be used over again ; this, however, is objectionable in the case of a double-action compressor, as the connection is liable to become choked with pieces of packing that find their way into the separator. When a rectifier is used, the separator- is in some instances connected therewith through a rotary cock, operated from the main shaft by means of a band, which cock is kept constantly working discharging a small quantity of oil at each revolu- tion into the rectifier, so long as any remains in the separator. The failure of oil in the separator is indicated by the connecting pipe between the latter and the separator becoming covered with frost, when the cock must be immediately thrown out of gear and the oil allowed to accumulate in the separator before re-starting it. When the separator is connected directly with the rectifier the cock in the connecting pipe should be opened periodically, say about every twelve hours. The oil may be discharged from the rectifier at about similar intervals, and the amount of oil that is found to be entering the com- pressor cylinder is an index to the state of the packing in the stuffing box, a large quantity being a certain sign that it requires renewal or seeing to. It is most important that the separator or oil collector be cleaned out at pretty frequent and regular intervals. The liquid ammonia receiver is invariably located below the con- denser, a supply pipe being led from it to the evaporator or refrigerator governed by the expansion cock or valve. Fig. 396 illustrates a type of ammonia receiver and oil trap made by the Triumph Ice Machine Co. The pipe shown passing through the vessel is the suction pipe to the compressor pump cylinder, and when this pipe becomes coated with frost, it materially assists in cooling the liquid ammonia, and thereby greatly increasing the effi- ciency of the plant. At the top of the receptacle is a wire gauze strainer, shown in plan on the left-hand side of the drawing, which prevents foreign bodies and impurities from gaining access to the system. (See also pages 76, 509, and 510.) ACCUMULATIONS OF DEPOSIT IN THE CONDENSER. It not infrequently happens that deposit accumulates on the ex- terior surface of the condenser coils from sediment in the water, and on the interior surface thereof from oil and foreign bodies. The smaller ammonia pipes may sometimes became filled with obstructions to the extent of completely blocking them up. These bodies may 550 REFRIGERATION AND COLD STORAGE. Fig. 396. Triumph Ice Machine Co. Ammonia Receiver and Oil Trap. Vertical Central Section and Detail Views. MANAGEMENT & TESTING OF MACHINERY. 551 consist of lumps of solder or other matter accidentally left in the tubes when making the joints, or of pieces of packing from the stuffing box carried over with the gas. The deposit or furring of the condenser coils or pipes is objectionable inasmuch as it acts as a non-conducting covering, and prevents them from freely transferring the heat to the cooling water, and the choking of other conduits is likewise followed by corresponding loss of efficiency, for example, that of one of those lead- ing to one of the refrigerator coils or sets of pipes will result in the latter not acting at all, or only very slightly. Complete choking up or obstruction of one of these latter conduits is evidenced by that particular pipe, and also the corresponding return pipe, not becoming covered with frost at all, or only so to a very small extent ; and a slightly less degree of frost upon any of these pipes indicates partial choking or obstruction, and a consequent very feeble action of the coil or set of pipes. The coils or pipes in the condenser should be frequently cleaned on the exterior with a suitable brush, and, whenever practicable, removed at fixed periods and carefully scaled. This is best and most easily effected by heating the tubes, care being taken, however, not to carry such heating to an injurious extent. The interior surfaces of the tubes can be cleansed by blowing steam through them at a con- siderable pressure. To clear small obstructions from a conduit leading to one of the refrigerator coils or sets of pipes, it is usually sufficient to turn the entire stream of ammonia into it. Should, however, the obstruction prove obstinate, and it be found impossible to shift it in this manner, an early opportunity must be taken to clear it by blowing steam through it. Any considerable choking of the conduits leading to the refrigerator coils is followed by a very marked decrease of efficiency in the latter. BREAKING JOINTS. Whenever a joint has to be broken, and any portion of the machine opened for any purpose whatever, it is absolutely essential that the whole of the ammonia contained in that part should be pumped or trans- ferred to another part, or if this cannot be done it should be dis- charged, preferably into water, which can readily be effected by means of a short strong india-rubber tube. On account of the already-men- tioned great solubility of ammonia in water, it will become readily absorbed, if the vessel into which it is discharged be kept sufficiently replenished with cool water. It is of the utmost importance that the 552 REFRIGERATION AND COLD STORAGE. rule of carefully removing all ammonia pressure before breaking a joint be strictly adhered to. In warm weather, or in hot climates, the joints will require con- stant attention, and periodical inspection, and tightening up of the bolts ; and at all times, even in the winter in this climate, they are liable to develop leaks through the working of the machinery. LUBRICATING QUALITIES, &c., OF AMMONIA. Ammonia being a good solvent, and having no effect upon iron or steel, the parts will become clean and free from deposit, after working for a short period, and the cylinder and piston will be found highly polished. Ammonia also possesses some slight lubricating qualities, and, therefore, after starting, no other lubricant need be introduced into the compressor cylinder. The cylinder covers, as also the valve box covers, should be occasionally removed and a thorough inspection made of the piston, cylinder, and valves. The latter are exceedingly apt to become cut or marked by fragments of scale, and require grinding in periodically. COMPRESSOR PI&TON ROD PACKINGS. A properly packed piston rod will remain in good order for at least six months, provided the rod be in first-rate condition and per- fectly true ; under contrary conditions, however, trouble will be experi- enced in a fortnight or less. The usual precautions to be observed in order to properly pack a steam engine or other stuffing box, which are well known, or should be so, to those in charge of ammonia plants, are equally applicable in the case of the compressor, but the herein- before-mentioned extensively searching nature of ammonia gas demands the exertion of extra care. ' These observations apply more especially in the case of a double-acting compressor. For single-acting compressors metallic packing will be found the best, that of Victor Duterne, the patent for which expired many years ago, being an excellent one for the purpose. A single-acting compressor stuffing box, being only subjected to the suction pressure, that is to say, to one of about 28 Ibs. per square inch, or even less, the maintenance of a tight joint is a matter of com- parative facility. With a double-acting compressor, however, the case is different, as the pressure will vary from 125 Ibs. at the lowest to some- times as much as 180 Ibs. at the highest, and with such a searching gas MANAGEMENT & TESTING OF MACHINERY. 553 as ammonia the stuffing box is a part likely to give the engineer in charge at least as much concern as any other portion of the machine. Should, however, the piston rod be in first-rate condition and perfectly true, a properly-packed stuffing box will, as already mentioned, enable a gas-tight joint to be maintained for six months or more ; with the opposite state of things leakage will probably occur in a fortnight or less, and in practice 'the rod will seldom be found to be in the first- named state of high perfection, consequently the joint may be expected to remain tight for any period of time between the two above- mentioned. The stuffing box should be of considerable depth, say a foot, a clearance of from J to f in. being left between the piston rod and its inner wall. Fig. 397 is a diagram from a sketch given in an American journal showing one form of stuffing box and method of Fig. 397. Stuffing Box and Packing for Ammonia Machine. Longitudinal Section. packing, from which it will be seen that it is packed in two sections, a steel lantern A, some inches long, being inserted centrally in the stuffing box B, with packing c on each side of it. Double-acting compressor stuffing boxes are best packed with com- binations of packings, metallic packings (which are found very suitable for the stuffing boxes of single-acting compressors) not giving good results with the former. Many of the special and patented packings will be found suitable. Plaited cotton packing, cut into suitable lengths, and inserted in the form of rings, may be employed, it being desirable, however, in this case to finish off with a couple or more rubber insertion rings. Packings consisting of india-rubber and duck, and indeed most packings of good quality containing india-rubber, are suitable when the piston rod is in good order, and the larger the proportion of rubber the 554 REFRIGERATION AND COLD STORAGE. better, as the ammonia has no injurious action upon the latter, only making it swell and become spongy, and thereby enabling a gas-tight joint to be maintained with but a trifling amount of friction. The packing should be driven home tightly, piece by piece, with a packing stick made of hard wood, and a mallet, the gland being finally screwed on by hand only, so as to allow for the expansion of the packing. This latter precaution is absolutely necessary in order to ensure the maximum life of the latter. When tightening up the gland care must be taken to do so equally all round, and not to screw up the nut on one bolt more than on any of the others. Several of the patented systems for preventing the occurrence of leakage of gas taking place past the stuffing box have been described in previous chapters, but the present purpose is only to endeavour to show ;how good a job can be made with ordinary stuffing boxes and packings. To CHARGE AND WORK A CARBONIC ACID MACHINE. The following directions, whilst applying more or less to all carbonic acid refrigerating machines, refer more especially to those made by Messrs J. & E. Hall, Ltd. Before charging, fill the compressor -with glycerine and run the machine for an hour or two with all the valves open wide. To charge the machine, suspend a flask of CO 2 , valve upwards, from a spring balance and connect by a copper wire to the evaporator. See that connecting joints are tight. The steel flasks contain about 40 Ibs. of CO 2 , and the number required will, of course, depend upon the size of the machine. Open the valve on the flask and on evaporator. The difference in weight between the empty and full flask will denote the weight of CO 2 that has passed into the machine. After the flasks are half empty, warm them with hot water. When empty close the valve whilst the flask is still warm. Should any CO 2 remain, it will be cold, and at the lower extremity. On first charging a new machine, blow the air out of the system by breaking the joint between the regulator and the pipe leading to it, the regulator being closed and all other valves open, and blow 2 or 3 Ibs. of CO 2 through. When charging, carefully examine all joints as the pressure rises, using soap and water for the purpose. The CO 2 gauges on condenser and evaporator indicate on the MANAGEMENT & TESTING OF MACHINERY. 555 outer circle the pressure in atmospheres, and on the inner circle the corresponding temperatures of CO 2 . When fully charged, start the machine with all the valves open and adjust the regulator (i.e., the inlet valve of the evaporator) so that the condenser gauge will indicate on the inner circle 5 to 10 above the temperature of the cooling water at the inlet to the condenser, and the evaporator gauge 10 to 15 below the temperature of the brine or water to be cooled. Under normal working conditions the compressor should be cold or partly covered with snow, and the delivery pipe from it should be rather warmer than the hand can comfortably bear. If the delivery pipe is not hot enough, slightly close the regulator, when the tempera- ture will quickly rise. If the compressor becomes warm, it points to the regulator being insufficiently open. Should it be impossible to secure the conditions above-mentioned, the system is short of gas. To further test this, close the regulator, and if the evaporator gauge falls rapidly and continuously, the system is short of gas. If properly charged, the gauge should remain almost stationary for several revolutions of the machine. Besides, if sufficient gas be present in the system, the condenser gauge could hardly rise at all, even after working two minutes. When short of gas, or in doubt, insert more, extra gas in the system, up to a quarter charge, will do no harm. It will be indicated by the condenser gauge showing 20 or more degrees above the inlet water temperature. If the machine be short of gas the refrigerating work done will be but a fraction of its proper duty. The temperature of the brine to be maintained depends, of course, upon the refrigeration that is to be performed. The clearance spaces at the ends of the compressor being small, they must be maintained equal at both ends. The hydraulic leathers forming the piston packing will require examination and removal occasionally, and it is particularly necessary that the nut securing these leathers should be well screwed up and locked. After putting in new leathers it is advisable, two days after starting, to tighten up the nut again. The suction and delivery valves should be examined periodically. When they require re-grinding, spare ones may be put in. In machines with the valve seatings making double joints, see that both copper rings are equally crushed by the valve casing. Leakage at the outer joint will indicate itself outside, but at the inner joint will not be perceptible except in reducing the work done by the machine. 556 REFRIGERATION AND COLD STORAGE. To test the work of the compressor, close the regulator, when the evaporator gauge should be pumped down from say 25 atmospheres to 5 atmospheres in about 200 revolutions. If slower, either the valves or the pistons are faulty. The gland is packed with two hydraulic battens, between which a pressure of glycerine is maintained by means of the special lubricator provided. The gland should not be screwed up too hard. The lubricator will require pumping up after some hours' work, and when the piston has moved 4 in. This, however, should not occur under three hours if the gland battens and compressor rod are in good order. The lubricator valve should be open a full turn. The glycerine which leaks from the gland should be caught, and after filtering, used again. Great care should be taken to keep the compressor rod free from scratches or marks, which would rapidly destroy the gland leathers. If short of leathers, the gland may be temporarily packed with ordinary tallowed packing, thus : first put in two or three turns of packing, then the spiral ring, and then fill up with packing, care being taken that the ring comes opposite the glycerine outlet when the gland is screwed up. Any glycerine passing into the compressor will be caught in the separator, and must be drawn off twice daily by slacking the nut at the bottom, and after filtering, used over again. All glycerine used should be free from water, acid, and dirt. On the suction side of the compressor is a strainer, and, with a new machine, this should be taken out and cleaned after the first and second day, and then occasionally. When stopping, it is not necessary to close any valves. The gauges will then equalise, standing at the pressure of the evaporator. Before starting, care should be taken to see that all the valves are open, a safety valve, however, is provided to relieve the pressure should this be neglected. The speed will vary in accordance with the size of the machine. It is particularly necessary that all pipes, joints, and glands of spindle-valves should be carefully examined and kept tight. For the first few days especially they should be examined daily, and all bolts and gland-nuts screwed hard up. The most minute leak should be instantly stopped. To examine the compressor, close the suction and delivery, screw down valves, and slack off a joint to let the gas escape. Make sure all pressure is gone before opening up. When the machine is stopped for a week or more, the piston rod should be withdrawn and oiled, or painted with white lead and tallow. MANAGEMENT & TESTING OF MACHINERY. 557 FREEZING OR CHOKING UP OF COMPRESSION SYSTEM. In working a compression machine considerable trouble is fre- quently experienced owing to freezing or choking up. This is caused by small particles of moisture entering with the gas from the com- pressor, or from the escape of glycerine or oil through the separator, which gradually accumulates in the system, and finally solidifies at the bottom of the evaporator or refrigerator coil, or at the expansion or regulator valve or cock. The latter place is the least objectionable, and as a general rule it can be cleared away by quickly throwing the valve open to its fullest extent. To clear the evaporator or refrigerator coil, a cock should be fitted to the evaporator or refrigerator casing or shell as low down as possible, and to this should be connected a steam pipe or hose from any available source of supply, such as a drain-cock on the steam pipe to the engine. The steam should be turned on slowly, and the temperature of the brine in the evaporator or refri- gerator raised to about 70 Fahr., the overflow cock from the evaporator to the brine tank being opened. The effect of this will be to liquefy the oil on the interior of the coil, and it will then run down to the bottom of the latter where the expansion valve should be full opened, so as to communicate with the condenser. If the compressor be then slowly started in the ordinary manner, in about half an hour the oil will float to the top of the liquid and may be drawn off at the separator. In drawing off or clearing out the separator the drain valve should be prevented from getting too cold, as if it does so the gas will come away in semi-solidified form, and there will be considerable wastage. The clearing out will be necessary about every three or four weeks, and lasts between one and two hours, the rise of efficiency in the machine being very perceptible. In charging a system, it is always desirable to pass the gas from the charging cylinder through a gas drier, so as to thoroughly cleanse and extract all moisture from it. This drier consists of a vessel fitted with a suitable inlet and outlet valve, and a drain or purging cock, and charged with alternate layers of chloride of calcium and cotton wool. This apparatus can be also used for the cleansing or purification of the gas already in the system, by connecting the outlet valve on the condenser with the inlet valve on the drier, closing the expansion and condenser outlet valves, and disconnecting the pipe between them. Then opening the outlet from the condenser, inlet to the drier, outlet, 558 REFRIGERATION AND COLD STORAGE. and charging valve on the top of the evaporator or refrigerator, and by working the compressor very slowly, any impurities in the gas will be taken up by the calcium and cotton-wool in the drier. LUBRICATION OF REFRIGERATING MACHINERY. This important point, which has been already touched upon in previous portions of this work, is apt to be as much neglected by users of refrigerating machinery as it is by users of other types of machinery. It will be well for these gentlemen to at once dismiss from their minds the idea that low-priced inferior quality oils are really the cheapest, and understand that on the contrary not only are high grade oils necessary to ensure the highest efficiency of the machinery, but that they are also the least expensive in the long run. In refrigerating machinery the use of three different kinds of oil is demanded : steam cylinder oil, oil for general use, and compressor pump oil. Oil for the steam cylinder : Good cylinder oil is entirely free from grit, does not gum up the valves and cylinder, and does not evaporate rapidly on exposure to the heat of the steam. The quality of a cylinder oil is demonstrated on removal of the cylinder head. If the oil is of good quality the wearing surfaces should appear well coated with lubricant, which will not show a gummy deposit, or blacken on the application of clean waste. Oil for general use on all the bearings and wearing surfaces of the machine proper : This may be any oil that will not gum, is not too limpid, possesses a good body, is free from grit and acids, is of good wearing quality, and flows freely from the oil cups at a fine adjustment without a tendency to clog. For the larger bearings it is well to use a heavier grade of oil. Oil for use in compressor pumps : When it is necessary to use oil in these it should be what is known as zero oil, or cold test oil, that is to say, that it should be capable of withstanding a very low temperature, without freezing, and it should be the best quality. American makers recommend the use of the best paraffin oil and clear West Virginia crude oil. Mr F. E. Matthews, in dealing with this subject in Power and the Engineer, New York, says, that in order that the oils used in the system shall not stiffen prohibitively at the low temperatures en countered, and not be saponified by the ammonia, only very light mineral oils can be employed. Such oils range from 22 to 30 Be., corre- MANAGEMENT & TESTING OF MACHINERY. 559 spending to a specific gravity of from 0*924 to 0*88. These oils should have a cold test of about zero Fahrenheit, to obtain which they will have a flash point of between 310 and 400 Fahr. This low flash point implies that a considerable amount of vapour will be given off at a much lower temperature. Since discharge temperatures of compression machines often approach these temperatures, it is obvious that a con- siderable amount of oil will pass to the condenser, not as a liquid but as a vapour. Under such conditions, since there is no material cooling effect in the oil separator, only liquid oil would be precipitated at that point. LEAKS IN AMMONIA APPARATUS. Leaks are readily detected by the smell of the escaping ammonia gas when the machine is being filled ; at a later stage, when working, their detection is not so easy. During the operation of the machine when the liquor or brine in the tanks commences to smell of ammonia it indicates a considerable leakage. It is recommended to test the liquor or brine periodically with Nessler's solution or otherwise. Nessler's reagent, which is the best to use for the discovery of traces of ammonia in water or brine, consists of 17 grms. of mercuric chloride dissolved in about 300 c.c. of distilled water, to which is added 35 grms. potassium iodide dissolved in 100 c.c. of water, and constantly stirred until a slight permanent red precipitate is produced. To the solution thus formed is added 120 grms. of potassium hydrate dis- solved in about 200 c.c. of water, allowed to cool before mixing ; the amount is then made up to 1 litre, and mercuric chloride added until a permanent precipitate again forms. After standing for a sufficient time, the clear solution can be placed in glass-stoppered blue bottles and kept in a dark place. If a few drops of this reagent be added to a sample of the suspected brine or water in a test-tube, or other small vessel, and the slightest trace of ammonia is present, a yellow coloration of the liquid will take place ; a large quantity of ammonia will produce a dark brown. When the leaks are comparatively insignificant they can be closed in the usual way, by solder, using as a flux muriatic or hydrochloric acid killed with zinc. In some instances electric welding may be resorted to with advantage, or the leak may be closed by means of a composition of litharge and glycerine mixed into a stiff paste, bound with sheet rubber, and covered with sheet iron clamped firmly in position. When, however, the leak is at all serious it is usually the better plan to at once put in a new coil, or a new length of pipe. 560 REFRIGERATION AND COLD STORAGE. LEAKS IN CARBONIC ACID MACHINES. To detect these, smear the joints with a solution of soap and water, and any leakage of gas will be evidenced by the formation of bubbles. Carbon dioxide or carbonic acid being a completely inodorous gas, precautions are required to prevent the occurrence of leakage. If the joints, however, are properly made to start with, they are found in practice, when once tight, to remain so for years. EFFECT OF A COATING OF ICE ON DIRECT EXPANSION PIPES. DEFROSTING REFRIGERATING COILS. INCRUSTATION ON CONDENSER COILS. The effect of a coating of ice on direct expansion pipes, according to an authority (Mr F. E. Matthews) writing in Power and the Engineer, New York, may be shown as follows : Assuming a heat transfer of 10 B.T.U. in round numbers per hour per square foot per degree of difference in temperature inside and out, for a flat metallic refrigerating surface, and an equal amount of sheet ice 1 in. thick, it follows that the heat transmission through 1 sq. ft. of direct expansion cooling surface insulated with a layer of ice 1 in. thick will be only one-half that of the uncoated surface. As a matter of fact, it would seem from the context that the value of 10 B.T.U. given as the heat conductivity of ice applied to plate-ice conditions under which the wetted surface of the submerged ice will transmit materially more heat than a dry surface in contact with air. This would indicate that the decrease in heat-transmitting capacity of direct expansion surfaces in air due to a coating of ice is even more than 50 per cent. This condition will be partially offset by the fact that on account of the increasing diameter the layer of ice in the case of cylindrical surfaces such as pipes (which, together with the fact that such coatings usually present an irregular surface, further increase the heat-absorbing area) may increase the heat transmission sufficiently to make up for the lesser heat transfer between the air and dry ice, and make 50 per cent, at least a reasonable estimate of the loss in heat-absorbing capacity due to 1 in. of ice. Under average commercial conditions of intermittent frosting 1 sq. ft. of direct expansion surface in air is usually credited with a heat transmission of only from 2 to 4 B.T.U. per hour per degree difference in temperature. Brine pipes may be readily defrosted by the circulation of hot brine. This may be accomplished through the main feed and return MANAGEMENT & TESTING OF MACHINERY. 561 headers where the operation does not have to be performed very frequently, or, as in abattoirs, where the excessive amounts of moisture from the hot meats to be chilled make the accumulation of frost very rapid, or by a separate set of defrosting headers. In the case of direct expansion coils, the defrosting method probably most satisfactory where the cold-storage temperatures are above 32 Fahr. is to instal sufficient coil surface to allow a part of the coils to be shut off at any time, so that the frost will melt without artificial heat, and at the same time produce a certain amount of useful refrigeration. If it is necessary to force the defrosting process by the use of outside heat, a hot gas line from the condenser may be connected to the liquid line connections to the separate coils just inside the expansion valves. The hot gas, after melting the ice as it passes through the coils, returns to the compressor together with the return gas from the remaining coils. Where the temperatures carried in the cold-storage compartments are below 32 Fahr., and in which the defrosting cannot be effected without the use of artificial heat, often very objectionable, two methods are available, viz., that of forcibly removing the ice with scrapers, and that of suspending over the pipes trays of calcium chloride. This substance is an exceedingly deliquescent salt, which in absorbing moisture from the air forms a saturated calcium brine which freezes at a very low temperature. In trickling down over the coils, the brine melts the ice, forming a more dilute brine, which is then conducted away to the sewer, or, if the quantities involved warrant the expenditure of labour, may be evaporated and the calcium chloride recovered. While the comparatively high working temperature of condenser coils, together with the usually ample provisions for draining each separate coil, prevents the accumulation of such large quantities of oil as are often lodged in expansion coils, condenser coils are exposed to another source of loss of efficiency from without, where the avail- able cooling water is abnormally hard or carries a large amount of suspended matter. Ammonia condensers, and especially steam con- densers, soon become coated with a deposit of scale or mud, which, if not properly removed, becomes a more or less effective insulator according to the composition of the deposit. The heat conductivity of metallic surfaces is not the same per degree difference in temperature at medium and low as it is for high temperatures, and it does not therefore follow that the resistance offered by the scale accumulating on the outside of atmospheric and submerged ammonia and steam 36 562 REFRIGERATION AND COLD STORAGE. condensers is the same as that of scale on the inside of a boiler. However, some slight idea of the extent of the loss may be gained from the fact that in steam boiler practice, the insulating effect of scale results in thermal loss corresponding to 2 per cent, of the fuel for each -^ T in. in thickness of scale. Condenser surfaces like those of steam boilers, expansion coils or any other heat-transmitting surfaces, should be kept as free as possible from deposits of foreign matter. COLD-AIR MACHINES. The proper management of cold-air machines is far simpler than that of those working on other principles, the exact treatment of each particular machine, however, varying of course somewhat with the make. In all machines, however, the parts most liable to give trouble are the valves, and these, as also the pistons and slide valves, should be periodically tested, and any defect promptly remedied. TESTING. The object of testing a refrigerating plant is in order to ascertain what it is capable of performing under comparable normal conditions, and as regards the amount of refrigeration produced in relation to the expenditure of work, and the coal consumption. To determine the efficiency of an installation on the compression system, the following fittings are required, viz., an indicator, so that diagrams can be taken from the compressor ; stroke counters, to enable the number of strokes made by the steam engine and brine pumps to be ascertained ; and mercury wells, to admit of the temperature being obtained at various points throughout the system. In making a test it is desirable that it should last at the very least for fully twelve hours, and it is better to carry it on for twenty-four hours. The number of readings which it is desirable should be taken from the various instruments will vary in accordance with whether or not the work is steady or otherwise, and the person carrying out the test will have, of course, to use his own judgment on this head. Where artificial ice is made, for example, twice an hour will be sufficient, whilst on the other hand, four or more readings per hour should be taken in cases where the variation in the temperature of the materials to be cooled is wide. Indicator diagrams should be taken from both MANAGEMENT & TESTING OF MACHINERY. 563 the steam engine cylinder and the compressor cylinder every two hours. A mercury well, for a horizontal pipe, when the latter is of suffi- cient dimensions, is shown in Fig. 398. It consists in a short piece of tubing closed at its lower end, and fitted into the pipe by means of a suitable bushing. It is filled about three parts full of mercury, and Fig. 398. Mercury Well for Horizontal Pipe. Vertical Section. Figs. 399 and 400. Mer- cury Well for Vertical Pipe. Vertical and Hori- zontal Sections. the thermometer, which should have an elongated cylindrical bulb, is held in position therein by means of a perforated cork. For vertical pipes, or pipes of very small dimensions, where this arrangement would be impracticable, the well is recommended by Mr Redwood* to be formed (as shown in vertical and horizontal section in Figs. 399 and 400) by means of a wooden or other block, one side of which is shaped to the outline of the pipe to which it is to be applied, and has * " Theoretical and Practical Ammonia Refrigeration." 564 REFRIGERATION AND COLD STORAGE. a suitable recess formed in it. This block is firmly secured against the pipe by metal straps in such a manner that a portion of the wall of the well will be formed by the pipe, the latter being scraped perfectly clean at that part. The joint between the block and the pipe must be made perfectly tight, which can easily be effected by means of a little white lead paint, as there is no pressure, and the whole should be surrounded by a thick layer of non-conducting composition, through which the stem of the thermometer is permitted to project. The points in the system where it is desirable to locate the mercury wells are : -The suction pipe just at its connection with the compres- sor ; the discharge pipe, as close as possible to its connection with the compressor ; the ammonia discharge pipe from the condenser, as near the latter as practicable. Where a brine circulation is employed : The pipe or manifold supplying the various coils or sets of pipes in the refrigerator ; the discharge pipe of the refrigerator ; the brine discharge pipe, at the point where it connects to the refrigerator ; and the brine return pipe in proximity to where it connects with the refrigerator. An excess condensing pressure is invariably found in ammonia compression machines. This excess of the actual working condensing pressure over the theoretical is caused by the ammonia gas being im- prisoned in the comparatively confined space afforded by the coils or pipes in the refrigerator, and the excess pressure is more marked in a horizontal compressor running at a high speed of, say, 140 revolutions per minute, than it is in vertical ones having only a low speed of from 35 to 60 revolutions per minute ; it varies, moreover, in almost every make of compressor. At a low suction pressure of about 15 Ibs. it should not be more than 10 Ibs., but with a suction pressure of, say, 27 or 28 Ibs. it may rise to 50 Ibs., or even more. The condensing pressure affords a means of ascertaining whether or not the apparatus contains the proper full charge of ammonia, or if the losses sustained by leakage are sufficient to render it necessary to insert an additional supply. For this reason it is advisable for the person in charge to keep a record in a proper book, suitably ruled for the purpose, of the temperature of the condensed ammonia when leaving the condenser, and also of the condensing and suction pressures, at regular intervals of, say, three hours. This will enable him to follow the state of the ammonia charge; for example, if the condensing pressure is found to be gradually falling during a three months' period, as compared with the average condensing pressure of the previous three months, whilst at the same time the condensing temperature and the suction pressure remain constant, it will be evident that the charg e MANAGEMENT & TESTING OF MACHINERY. 565 of ammonia has become reduced by leakage to a sufficient extent to require replenishing. This reduction in the condensing pressure is caused by the diminution in the charge of ammonia giving larger con- denser space, the gas having thus a much more extended worm, coil, or tube space wherein to condense and liquefy, and hence the decrease. As a general rule it may be taken that, whenever the condensing pressure is found to have fallen about 8 Ibs., enough ammonia to restore the original condensing pressure should be inserted into the machine. The following method of testing the capacity of a refrigerating machine is given by Mr Constanz Schmitz in the Eis und Kalte Industrie : " In testing the effective capacity and the consumption of power of a refrigerating machine, it has been hitherto usual to take the amount of heat removed per hour, and the power consumed in indicated horse- power. This, however, does not afford a satisfactory basis upon which to judge of the relative merits of machines under test. If, for example, the theoretical capacity of any particular refrigerating machine be taken, it will be found in every instance that this capacity will not be reached in practical working." A more satisfactory means of comparison is furnished by the results obtained from a large number of caloric production and power con- sumption tests, which, however, under varying working conditions, and for different sizes of the machines, will not be found to correspond. To avoid, therefore, possible mistakes, and to facilitate the work, the caloric production and the consumption of power should be reduced to a special unit, and for this purpose the following method is proposed : It is expressed in the following manner : 1 . Specific refrigerating efficiency = Q sp. That number of calories which is indicated per 1 cubic metre hourly volume of stroke of the compressor, in the evaporator. 2. Specific consumption of power = N sp. That number of horse-power which is indicated in the air com- pressor for 10,000 calories evaporator production. Let a compressor have, for instance, the following dimensions : Cylinder diameter - d = 250 mm. Piston stroke s = 420 Piston rod - 8= 55 Number of revolutions per minute - n= 65 ,, 566 REFRIGERATION AND COLD STORAGE. Then its hourly volume of stroke is : V=15.n.s.7r. (2c? 2 -8 2 ) = 156-920 cub. metres (and since 1,000 cub. dm. = 1 cub. metre, also 1 litre = 1 cub. dm. we have : Y = 156,920 litres). Should now the evaporator productions per hour be found by Q2 = 63,750 Cal., the specific refrigerating efficiency of the machine will be: 63,750 Af . a , Should at the same time during the caloric trial 2 3 '7 H.P. be indicated in the compressor, then the specific consumption of power will amount to : If then, in addition to this, the evaporator temperature, that is the mean temperature of the volatile cold-producing agent or medium, and the liquefaction temperature in the condenser be given, four figures afford a practical demonstration of the performance of the machine in question. On the basis of these figures, refrigerating machines may be con- veniently compared as regards their productive capacity. The com- parison as regards the specific refrigerating capacity Q sp. is, of course, only possible directly between machines constructed to operate on the same system, while the comparison as regards the specific amount of power required is rendered directly possible between machines con- structed to operate on any system. INTERPRETATION OF COMPRESSOR DIAGRAMS. The interpretation of a compressor diagram with respect to the working, valves, defects, &c., of the latter are given as follows by Hans Lorenz, in "Neuere Kuehlmaschinen," Muenchen and Leipzig, 1899 : " Assuming all the parts of the machine to be in good order, then the diagram will have the general appearance shown in Fig. 401. The suction line s is only slightly below the suction pressure line v, and the pressure line D is only slightly above the condenser pressure K. Small projections at the pressure and suction line indicate the work required to open^the compressor valves, and the effect of clearance is shown by the curve R, which latter cuts the back pressure line after the piston has commenced to perform its return or back stroke, and consequently MANAGEMENT & TESTING OF MACHINERY. 567 reduces the suction volume to that amount. It can also be seen from this diagram that the vapours are taken in by the compressor, not at the back pressure, but at what may be called the suction pressure, which is somewhat lower. This is the reason that the compression curve c does not intersect the back pressure line until after the piston Fig. 401. Diagram from Com- pressor in good order. Fig. 402. Diagram from Com- pressor indicating an Exces- sive Amount of Clearance. has changed its direction of movement. The theoretical volume of the compressor, as indicated by the line v, is consequently reduced in practical working for vapours possessing a certain tension. In Fig. 402 is shown a diagram taken from a compressor having an fvTMOSPHCriC L Fig. 403. Diagram from Com- pressor indicating Binding of Pressure Valve. Fig. 404. Diagram from Com- pressor indicating too great a Resistance in Pressure and Suction Pipes. excessive amount of clearance. In this case, it will be seen, the back expansion line R passes through a flat course, and thereby reduces the useful volume of the compressor. Fig. 403 is a diagram which indicates the binding of the pressure valve, which may be due to an inclined position of the guide rod of the 568 REFRIGERATION AND COLD STORAGE. valve. This deficiency also frequently causes a delay in the opening of the pressure valves, a state of things indicated by a too great projection in the pressure line. As soon as the valve is once opened the pressure line pursues its normal course until the piston commences its return stroke, when the defect is again manifested in the back pressure line, as mentioned. Fig. 405. Diagram from Com- pressor indicating Binding of Suction Valve. ATMOSPHERIC LINE. Fig. 406. Diagram from Com- pressor indicating Leaking of Compressor Valve. Fig. 404 shows a diagram indicating too great a resistance in the pressure and suction pipes respectively, when the valves are over- weighted. In this case the pressure and suction lines are at a compara- tively great distance from the condenser pressure line and the back pressure line. The remedy for this is to replace the valve springs by Fig. 407. Diagram from Compressor indicating Defective Packing of Piston. weaker ones ; and should there be then no marked effect, then the pipe lines and shut ting-off valves should be inspected and, if found necessary, cleaned. Fig. 405 indicates the binding of the suction valve, by which a considerable decline is caused in the pressure at the beginning of the MANAGEMENT & TESTING OF MACHINERY. 569 suction, which is consequently shown by an increased projection in the commencement of the suction line. At the beginning of compression this defect makes itself felt by causing a delay in the latter, which effect is also shown on this diagram. Fig. 406 shows leaking of the compressor valves. In this diagram the projections in the compression and suction line do not appear, but the compression line gradually merges into the pressure line, and the back expansion line passes gradually into the suction line. If the leak in the pressure valve is the predominant one, then the compression curve will be almost in a straight line and very steep ; if, on the contrary, the leak in the suction valve is the predominant one, then the compression line will run a rather flat course. Fig. 407 indicates that the piston is not well packed, and being leaky, the vapours are permitted to pass from one side of the piston to the other, thus causing a very gradual compression, and as a result a compression line having a flat course. On the other hand, a longer time will be taken before the suction line reaches its normal level on the return or backward stroke, inasmuch as the suction valve is pre- vented from opening until such time as the velocity of the piston becomes such, tha the amount of vapours leaking past the piston is insufficient in amount to fill the suction space. The pressure then gradually diminishes and the suction valve begins to act, as is shown on the diagram. It is to be understood that several of the defects above-mentioned may exist at the same time. ABSORPTION MACHINES. Liquid anhydrous ammonia is supplied in iron or steel drums or flasks in which it is contained at a pressure varying in accordance with the temperature of the liquid from 120 Ibs. to 200 Ibs. per square inch. This liquid is charged into the machine and is brought into contact with the substance to be cooled or frozen at a sufficiently low pressure to allow of its boiling point being lower than the temperature at which the substance to be treated has to be maintained. During normal working of an absorption machine the cold strong or rich liquor, or aqua ammonia, should contain about 60 per cent., and the hot poor or weak liquor, or aqua ammonia, about 20 per cent, of pure ammonia. This admits of calculating the amount of liquid required for a given amount of refrigeration. The pressure in the absorber is as a general rule maintained at about 15 Ibs. per square inch, that in the generator 570 REFRIGERATION AND COLD STORAGE. may be anything between 110 Ibs. to 180 Ibs. per square inch in accordance with the temperature of the condensing water. To ensure these conditions strong ammonia liquor has to be pumped from the absorber into the generator, the small pump used for this purpose being the sole part of the system in motion, and corresponding practi- cally to the feed pump of a boiler. The strong or rich ammonia liquor is in as cold a condition as possible, and as its return in that condition to the generator would entail the consumption of more heat for evapora- tion, and a consequent larger expenditure of fuel, which entails expense, this strong ammonia liquor is first raised to as high a temperature as possible by passing it through an exchanger. In this latter the hot weak ammonia liquor passes from the bottom of the generator back to the absorber through a coil, the strong or rich ammonia liquor being conducted between the shell and the coil. The level of the liquor in the generator is maintained slightly above that of the heating coils. The ammonia gas driven off contains a certain amount of moisture, and it must be dried before passing to the condenser. This is effected in the rectifier, where the moisture in the gas is condensed by slightly heated condensing water and the gas merely cooled, the first returning to the analyser, and the second passing on to the top of the condenser to be condensed and liquefied. It is found advisable to further cool the weak liquor in a double pipe weak liquor cooler before its return to the absorber. AMOUNT OP WATER REQUIRED IN REFRIGERATING APPARATUS. Vulcan Iron Works. For each rated ton refrigerating capacity (twenty-four hours), allow 1 J gals, of 70 Fahr. water per minute for ammonia condenser. For each rated ton ice-making capacity (twenty-four hours), can system, with distilling and purifying apparatus, allow 3 to 4 gals, of 70 Fahr. water per minute for all purposes. 5 to 8 tons of ice can be produced for each ton of good coal consumed, depending upon the size and care of plant, &c. DETERMINATION OF MOISTURE IN AIR (Siebel). The moisture in the atmosphere may be determined by a wet bulb thermometer, which is an ordinary thermometer the bulb of which is covered with muslin kept wet, and which is exposed to the air, the moisture of which is to be ascertained. Owing to the evaporation of MANAGEMENT & TESTING OF MACHINERY. 571 the water on the muslin the thermometer will shortly acquire a stationary temperature which is always lower than that of the sur- rounding air (except when the latter is actually saturated with moisture). If t is the temperature of the atmosphere, and t l the temperature of the wet bulb thermometer in degrees Celsius, the tension e of the aqueous vapour in the atmosphere is found by the formula e = e l - 0-00077 (t-t l )h, e l being the maximum tension of aqueous vapour for the temperature t l as found in table and h the barometric height in millimetres. If e^ is the maximum tension of aqueous vapour for the temperature t, the degree of saturation H is expressed by H-t and the dew point is also readily found in the same table, it being the temperature corresponding to the tension e. PSYCH ROM ETERS. Instead of the wet bulb thermometer alone it is more convenient to use two exact thermometers combined (one with a wet bulb and the other with a dry bulb, to give the temperature of the air), to determine the hygrometric condition of the atmosphere or of the air in a room. Instruments on this principle can be readily bought, and are called psychrometers. If they are arranged with a handle so that they can be whirled around, they are called " sling psychrometers." These permit a quicker correct reading of the wet bulb thermometer than the plain psychrometer, in which the thermometers are stationary and are impracticable at a temperature below 32 Fahr., while the sling instru- ment can be read down to 27 Fahr. HYGROMETERS. While the term hygrometer applies to all instruments calculated to ascertain the amount of moisture in the air, it is specifically used to designate instruments on which the degree of humidity can be read off directly on a scale without calculation and table. Their operation is based on the change of the length of a hair or similar hygroscopic sub- stance, under different conditions of humidity. 572 REFRIGERATION AND COLD STORAGE. t I g I I 1 1 ! I I > O H O Sr-H O 1 ^O O "O iO>OiOI>OO' < (N iO t^* O CN O O a s^ i 3 U d-HCCTi!coc5c4c>i^cot^i-H'^dt^ 3 n. l) 5 P. 5 38 5 5? iiiiiiiiiiiiiii q CJ 3 "H O1 C^ ^ CO 00 00 O5 O 1 '-"i ^ CO O O 1O iO O : : : : : ; :5oiQ55i>tO oi ^ oi o K COCOCOCOCOCOCO-*Tt rH r-H i-H CQ (^ CO CO CO <* tQ CD t^O5~(N CO CO T^ CC5 IT^OS 88888888SSS8S CHAPTER XXII THE PRODUCTION OF VERY LOW TEMPERATURES Early Investigators and Experimenters The Cascade System The Regenerative Method Properties of Liquid Air Physical Constants of Liquefied Gases. EARLY INVESTIGATORS AND EXPERIMENTERS. The Cascade System. THE first experimenters in the liquefaction of gases were Mouge and Clouet before 1800, who succeeded in liquefying sulphur dioxide; Northmore in 1805, who liquefied chlorine and sulphurous acids; Faraday, 1823, who liquefied chlorine sulphuret of hydrogen, carbon dioxide, nitrous oxide, cyanogen, ammonia, and hydrochloride acid. Habrier, Natteur, Andrews, and Siemens, the latter making, in a pro- visional application filed in 1857, the suggestion that refrigeration might be produced by expanding a compressed gas either in a cylinder doing work or freely to a lower pressure, and using this cold gas to cool before expansion the gas coming to the apparatus. This, it will be seen, is the basis upon which the latest investigators have proceeded, and which has admitted in the closing years of the last century of the liquefaction of all gases being effected. In 1878 Cailletet and Pictet, working quite independently of each other, succeeded in liquefying certain of the so-called permanent gases. The method employed by the first was to compress the gas under very high pressure, cool it moderately, so that it was still above its critical temperature, and then allow it to expand suddenly by opening a cock or valve by which the pressure on the gas was relieved, doing work against a column of mercury which formed the equivalent of a piston for compressing the gas. In this manner the gas cooled itself, the expansion being sudden and almost adiabatic, and the temperature was reduced below the critical point, whilst the pressure was still sufficiently high to liquefy the gas at the temperature which it had then acquired. 588 VERY LOW TEMPERATURES. 589 Cailletet in the above manner experimented with various gases, amongst others nitrous oxide or laughing-gas, acetylene, and carbon monoxide, and succeeded in obtaining a mist of hydrogen. He was the first to use liquid ethylene as a cooling agent. The second, or Pictet, on the other hand employed what has been styled the cascade or successive cycle system, and is described by Professor Ewing as follows : * "The general idea of this method is illustrated in Fig. 410. Imagine a refrigerating agent, such as carbonic acid, to have been Ethyfene Oxygen -148 / 7 80C. -220 -130C -200C. Fig. 410. Diagram illustrating the Cascade or Successive Cycle System of producing Very Low Temperatures. compressed and to expand through a valve into the chamber A, where it evaporates. In the example, as sketched, it is evaporating into the atmosphere. When carbonic acid evaporates freely to the atmosphere, it falls to a temperature of about - 80 Cent. It could be made to go 30 or more lower by using an air pump to preserve a partial vacuum in the chamber ; but, assuming the pressure A to be atmospheric, the temperature then will be about - 80 Cent. Now, we may use this as the condensing temperature of some other volatile material. The material which is indicated in the sketch is ethylene, which was not used by * Journal of the Society of Arts, 17th September 1897. 590 REFRIGERATION AND COLD STORAGE. Pictet, but has come into use subsequently and has done good service in the hands especially of Professor Dewar. It forms a convenient intermediate link between the comparatively easily liquefiable carbonic acid and the much more difficult oxygen. Ethylene has a critical temperature of -10 Cent., and needs only moderate pressure to liquefy it when exposed to a temperature of - 80 Cent. It is pumped at the necessary pressure into the inner vessel at A, and is there liquefied and passes through an expansion valve to the outer vessel at B, where it evaporates. The pressure in B is supposed to be kept at something not much over 1 in. of mercury, and in that case the temperature reached by the ethylene in evaporating will be -130 Cent. After expan- sion it is re-compressed, so that the part of the apparatus in which the ethylene is carried through its cycle may simply be regarded as a separate vapour compression refrigerating machine, the same as the ordinary machine using ammonia or carbonic acid ; B is the refrigerator and A is the condenser. " The remainder of the apparatus is another similar machine, using in this case oxygen as its working substance, and with B as its condenser. The critical temperature of oxygen is about - 150 Cent., and as the temperature in B is lower than that, the oxygen liquefies when com- pressed into the inner vessel at B. A moderate pressure of 20 or 30 atmospheres suffices. The liquid oxygen may be passed through a valve and evaporated again in the vessel c, and in that way a tem- perature of - 200 Cent, or lower can be reached, the temperature, of course, in this last vessel depending on the pressure in it, and con- sequently on the rapidity with which the pump worked. By working the pump tolerably fast to preserve a good vacuum in c, we can get down to something like - 220, or even - 225, Cent., a temperature which is no very long way above the absolute zero - 273 Cent. In Pictet's cascade of successive cycles, the substances used were sulphurous acid and carbonic acid. The ethylene is a useful addition, as giving readily a temperature considerably below the critical point of oxygen. Without it, however, Pictet succeeded in liquefying oxygen by the device of letting it suddenly escape when under high pressure, and after being cooled as far as the carbonic acid would cool it." Further experiments, made during the next decade by the two Polish chemists, Wroblewski and Olszewski, working together and using Cailletet's type of apparatus, and latterly Pictet's cascade system, for cooling the compression tube, confirmed the results obtained by Cailletet and Pictet on hydrogen in 1884. In this year (1884) Professor Dewar demonstrated at the Royal VERY LOW TEMPERATURES. 591 Institution that liquid air could be produced by the use of solid carbon dioxide and nitrous oxide as cooling agents, giving - 184 Fahr. ( - 120 Cent.). With a compression to 200 atmospheres, and subsequent expansion, about 5 per cent, of the air compressed was liquefied. Professor Dewar also devised the vacuum flasks for holding liquid gases which bear his name, and which consist of two glass walls with a sealed space between from which the air has been completely exhausted, and which consequently acts as the best possible insulator. By the addition to the vacuum-jacket of a film of mercury spread over the surface of the glass on the inner side of the outermost wall, a bright surface is produced which reduces the absorption of heat by the latter, and permits much less radiation to pass through. This vacuum vessel enables the rate of evaporation of a liquid gas to be reduced from one-fifth to one-sixth of that which would take place in the open air, and if the inner wall be coated as above described with mercury to form a heat mirror, the heat evaporation will then be only from one-twentieth to one-thirty-third that of the free rate. Until quite recently these flasks were the means by which liquid gases were handled and maintained in a static form. Subsequently Olszewski, after Wroblewski's death in 1888, replaced the glass tube of Cailletet by a steel one fitted with a stop-cock, and obtained enough liquids to be handled in Dewar flasks. Discarding after a time the Cailletet apparatus, as altered by Wroblewski, Dewar employed the Pictet apparatus, using, however, pumps to compress the gases previously made, and force them into the liquefying chamber, and he also employed ethylene in place of carbon dioxide, placed the draw-off cock within the cooling chamber, and still later adopted the regenerative principle suggested by Siemens, for cooling the chamber in the case of hydrogen liquefaction. In 1895 Dewar demonstrated that air in the liquid form could be frozen to a jelly-like solid by the expansion method, this jelly proving to be a mass of nitrogen with the liquid oxygen of the air contained in the interstices; this solid air melts instantly on contact with the atmo- sphere. In 1896 he effected the production of a jet of liquid hydrogen by means of the expansion of the cooled and compressed gas, and by the use of this hydrogen jet, oxygen and air were frozen to a solid white mass. In 1898 Dewar succeeded in collecting hydrogen in a static condition, -and in keeping it in this form by the use of one of his bulbs at a temperature of -396'4 Fahr. ( - 238 Cent.), only 64 Fahr. above the absolute zero. Amongst other workers in this field must be mentioned Professor 592 REFRIGERATION AND COLD STORAGE. Onnes of Leyden, and Moissau, the latter investigator together with Dewar having succeeded in liquefying fluorine, the last of the elements to yield. A considerable amount of attention, it is true, was devoted to the production of liquid air by the above-mentioned investigators, especially by Professor Dewar, but they were primarily interested in the scientific investigation of the properties of the elementary gases, and the former has been more particularly dealt with by Linde, Hampson, and Tripler, who have all been experimenting especially with a view to the simplification and cheapening of the production of liquid air in order that it might be made on a commercial scale, and they have all been working on the lines of direct regenerative action which was proposed by the late Sir William Siemens forty-four years ago. In this direction it should be stated that Professor Dewar had also been work- ing, combining cooling with a separate fluid, his experiments being, however, on a smaller scale suitable for a chemical laboratory. THE REGENERATIVE METHOD. As has been already mentioned, Siemens was the first to use the regenerative process, and in the specification of the provisional application already referred to he describes the employment of an interchanger to extract cold from the air already cooled by the refri- gerating machine, and thereby to cool the air which is on its way to be expanded. Siemens especially pointed out that theoretically, at least, no limit existed to the degree of cold which could be produced by the use of such an interchanger, and after giving an example of the temperatures that might be expected in a particular instance, he says : "These temperatures are mentioned, not as absolute temperatures, but to show that the principle of the invention is adapted to produce an accumulated effect or an indefinite reduction of temperature." Siemens' idea, observes Professor Ewing, was that the compressed air should pass through this interchanger, and should then be caused to do work in an expansion cylinder. This expansion would chill it, and it would then pass again through the interchanger, giving up its cold through the interchanger to the next succeeding supply of compressed air. The effect would be to make each fresh supply, on its way to the expansion cylinder, a little colder than the last. The cumulative fall in temperature resulting from this would only be limited by accidental losses due to conduction of heat from outside and to heat developed from friction within the machine. VERY LOW TEMPERATURES. 593 In 1885 Sol way took out a patent for an apparatus and process for producing, applying, and keeping up extreme temperatures by means of a regenerative method somewhat akin to that of Siemens, only that he employed a regenerator instead of an interchanger. With this apparatus Solway succeeded in reaching a temperature of about - 95 Cent., at which he found the losses of cold balanced the gains. In 1892 Windhausen obtained a patent for an apparatus for the production of extreme degrees of cold with an interchanger sub- stantially similar to that of Siemens, but employed in combination with an expansion cylinder. With this he obtained about the same degree of temperature as Solway, and this apparatus is said to be now in use on a commercial scale for such processes as the extraction of benzol from the mixed gases which are given off by the distillation of coal. The particular workers in this field, however, who have aimed at the simplification and cheapening of the production of liquid air, so that it might be made commercially useful, are, to take them in the order of their applications for patents, Tripler, Hampson, and Linde. Tripler's English patents were filed in 1891, Dr William Hampson's on the 23rd May 1895, and Dr Linde's three weeks later in the same year. A good deal of discussion has taken place as to which of these three should have assigned to them the real credit of having first pro- duced a practical machine. It is averred by some that the apparatus described by Tripler was impracticable, and by others that Hampson's provisional, specification was very brief, and so vague as to indicate but little. It certainly appears that the first to produce a practical working apparatus was Dr Linde, although he was the last to proceed to the Patent Office for protection ; it is on record that his apparatus, in a practical and workable form, was produced in the summer of 1893. Mr Tripler has been refused a patent by the U.S. Patent Office. The principle of the regenerative method of producing very low temperatures is, says Mr A. L. Bice, in a paper read before the American Society of Mechanical Engineers, December 1899, a perfect gas expanding to do work loses heat ; if this cooled gas be exhausted, so as to jacket the pipe through which the incoming gas enters, it will cool that incoming gas ; the process is cumulative without limit, if the machinery is frictionless and insulated against heat from the surrounding objects. Solway built a machine on this principle, but was unable to get lower than -139 Fahr. (-95 Cent.), on account of the heat due to the friction of the pistons and to conduction. In a perfect gas no lowering of the temperature would result from 38 594 REFRIGERATION AND COLD STORAGE. ; : lowering of the pressure by free expansion, but none of the so-called gases are perfect, and all are cooled somewhat by expansion through an orifice. Joule and Kelvin found that with air the fall of temperature is about '45 Fahr. (J Cent.), for each atmosphere difference of pressure at the orifice at ordinary temperatures, and that the effect increases as the temperature falls, because the gases are coming more nearly to the vaporous state. If, then, air be compressed to a high pressure, and be allowed to expand through a small orifice, it will become considerably cooled, and may be used to cool the incoming air, which, STORAGE TUBES DIAGRAM REP8ESENTING COMPRESSOR. END VIEW SHOWING 1ST AND 2tiD INTER -COOLER $= 5ES tt ,UJ u. 'K iZ G 5LEH' XPA or _J NSION VAUV n Es!N = * =s= VALVE FOR DRAWING = B Fig. 411. Diagram illustrating Tripler's Apparatus for the Production of Very Low Temperatures by the Regenerative Method. in turn, will lose heat by expansion. The process may be carried on until some of the air, on or before leaving the orifice, is liquefied. Mr Tripler's apparatus is shown in Fig. 411, and, as described by Mr Rice, "consists of a three-stage compressor, drawing air directly from the atmosphere, and driven by a steam engine. The air is taken first into the low-pressure cylinder, where it is compressed to 65 Ibs. per square inch. It is then sent through an intercooler to reduce the temperature to that of the atmosphere, and taken into the intermediate- pressure cylinder; from that, at a pressure of 400 Ibs., it is taken VERY LOW TEMPERATURES. 595 through a second intercooler to the high-pressure cylinder, where it is forced up to 2,000 to 2,500 Ibs., and thence sent to the after-cooler to be reduced again to the temperature of the atmosphere. The air is passed through a separator to take out all moisture, and then passes to storage tubes in which compressed air, not in the liquid form, may be kept. The liquefier is Mr Tripler's special invention. This takes the air from the separator, and by expansion through a coil of pipe and a small orifice, cools it to a low temperature. It passes up around the coil of pipe, cooling the air inside, and thus gives the regenerative action. The expansion valve is placed at a little distance above the bottom of the coil, so that some liquid air collects in the bottom of the latter, and thus serves to further cool the air as it comes to the expansion cock. The air which is to be drawn off collects in the liquefier just below the expansion valve, and may be drawn off at will. The expanded air escapes to the atmosphere after having been used to cool the coil of the liquefier. The capacity of the present plant is 2 or 4 gals, per hour, and the ice will begin to liquefy in fifteen minutes after the starting up. No data are available as to the power used in the compression." The provisional specification of Dr William Hampson's 1895 patent was, as above mentioned, extremely brief, and the following is the text in extenso : "The usual cycle of compressing, cooling and expansion, is modified by using all the gas after its expansion, to reduce as nearly as possible to its own temperature the compressed gas which is on its way to be expanded. With this object all the expanded gas surrounds the pipe or pipes of compressed gas through all their length from the point of expansion to the point of normal temperature, arid the length of pipe is sufficient to allow of the fullest possible interchange of temperatures between the compressed and expanded gas." In a subsequent patent the improved apparatus shown in vertical and horizontal sections in Figs. 412 and 413 is described. In this apparatus the interchanger is made with a tube or tubes coiled into spirals, the convolutions of which are separated by very narrow spaces, and with the coils lying one upon the other. The space between the tubes does not exceed ~ in. The gas after compression is purified by caustic potash or the like. The vacuum vessel 7 is supported by a cap 2 inside concentric glass tubes mounted between rings 3 and 5 held by a frame 4. Insulating or tight joints may be made at 5, 6, 7, 8. Cold carbonic acid or the like is passed on to the coils in the neigh- 596 REFRIGERATION AND COLD STORAGE. bourhood of the expansion joint, and thence over their other parts before beginning expansion of compressed gas, and the arrangement shown in Fig. 413 is used for supplying the cold carbonic acid free from solid particles. In this, the gas expands from the valve 7, which is kept at a proper temperature by a stream of warmer gas from the valve 2, and then any solid material is removed by filtering material 4 from the vapour which is led away by the pipe, &c., 7. Fig. 414 represents the 1898 type of the Linde apparatus, as de- picted in Mr Rice's paper, and which ap- paratus only differs in a few minor details from that made in 1893. It has been already stated that the fall of tempera- ture is proportional to the difference of pres- sures at the orifice, and this difference should, therefore, be large; the work required to com- press the air again will depend upon the ratio of the pressures, that is to say, upon the ratio Figs. 412 and 413. Hampson's Apparatus for the Production of Very Low Temperatures by the Regenerative Method. Vertical and Horizontal Sections. of compression, and should be as small as possible. This necessi- tates that both pressures be high for the most economical working, and, therefore ; Linde works his machine between 200 atmospheres and VERY LOW TEMPERATURES. 597 16 atmospheres for all the air by expanding through the valve marked a. One-fifth is then expanded to 1 atmosphere through the valve b so as to cool it still further, and about one-fourth of this amount is condensed. The expanded air is sent back in the outer pipes as shown, the part which is at 16 atmospheres to the compression pump, and the rest to the atmosphere, f is a separator and g a freezing Fig. 414. Linde's Apparatus for the Production of N^ery Low Temperatures by the Regenerative Process. Sectional Elevation. bath, both being used to remove the moisture from the air. d is the compression pump, and e a pump for supplying at 16 atmospheres as much air as escapes at b. c is the receptacle for the liquid air. In the earlier form of the machine none of the air was expanded below 50 atmospheres, and the air was cooled by a surface condenser supplied with water. With this apparatus about -9 quart of liquid can be obtained per hour with the use of 3 H.P., this being about !! 73 ^73 g = | ,3-0 .SP -o mo j o Density of Liq at Temperatur Given. SBf) JO ISU3Q O r~O5 05 0505 05 05 05 i $5 : 9 98 5S ^52 00 O5 O5 O5 O5 O5 O5 CO CO l> "^ *O O5 CO : 8 cp cp So PH 1 (N CO u? w Me o oo r^ co t I I O5 IO !> : co oo co i mp, of Saturated apour at Atmos. Pressure. I 1 s I I i I I O CO QU 3 05 09 ^^ 1 1 1 S 3 11 fr> O5 (N OO CO >O Criti per 0 TH co oo : o >o o co >o O5 O500 .lOi-HCOOO J III II 00 IO 00 >0 OO 00 l 2S rH CO CO w d 5 ffl o d*o WM '1 J p* ^^ a Iff 4 g ll -i -s,g g-lfi PH > $ H I '& & < 6 < % Hydrog Helium 00 05 O I-H 10 CO !> 00 O5 VERY LOW TEMPERATURES. 599 5 per cent, of the air handled, the first liquid will appear about two hours after starting up the machine. The following extended extract from Mr Rice's paper regarding the properties of liquid air will be of interest : " The physical constants which have been determined with regard to the liquefied gases are given in the foregoing table, which was pre- pared by Mr Walter Dickerson. It will be noted that the order of the liquefaction of the gases historically is almost exactly that of the de- scending critical temperatures. It is the attaining of a low temperature limit that has taken all the time and study that has been devoted to this matter. Some of the gases when in the liquid form are lighter, and some heavier than water, as shown by the values of specific gravity ; of the constituents of air, nitrogen is lighter and oxygen is heavier; the mixture, containing four-fifths nitrogen and one-fifth oxygen, is a little lighter than water. " Professor Jacobus and Mr Dickerson have-found the latent heat of air at atmospheric pressure to be about 140 British thermal units, but this figure is stated as only a rough approximation. This is about the only value which has been determined with regard to air in the intermediate or vaporous state. " Any calculations as to the efficiency of [liquid air as a fluid for a prime mover must necessarily be only approximate. The approxima- tions can, however, be made on the right side, and the air given the benefit of the doubt. "Professor Henry Morton has recently made some calculations regarding the maximum amount of power which could be obtained by the expansion of 1 Ib. of liquid air under certain circumstances. The same hypothesis which he used will be assumed and his figures adopted. " Suppose 1 Ib. of liquid air to be confined in a cylinder and heated to 70 Fahr., then let it expand at 70 to atmospheric pressure, the expansion to be hyperbolic. It is not known what the volume of the air will be at 70 before expanding, but it is certain that its ratio of expansion will be less than it would be if expanding from the volume of the liquid at -312 to the volume of the gas at 70 and atmospheric pressure. This ratio is something less than 800, hence we will call the ratio of expansion 800. The volume of 1 Ib. of air at 70 Fahr. and atmospheric pressure is 13 '3 6 cub. ft. " The work done in a hyperbolic expansion is W = p 2 x v 2 x log e R. 6oo REFRIGERATION AND COLD STORAGE. When p 2 = final pressure per square foot = 2,1 17 Ibs. ^2 = final pressure volume = 13*36 cub. ft. R = -J = ratio of expansion. v i W = 2,117 x 13-36 x 6-685 = 188,000 ft.-lbs. 188 000 ? = -095 = horse-power per pound of air used per hour, 60 x 33,000 and = 10*55 Ibs. of air per horse-power per hour, if the terminal pressure equals the back pressure, no compression and no clearance being considered. " This result cannot, of course, be realised, for there are many sources of loss which cannot be avoided, and which will make this figure for the weight of air per horse-power hour much higher. However, even if it could be realised in actual practice, it is only just inside of the figure which has been obtained in our best steam engines under practical working conditions. " In these figures the liquid is considered simply as a storage medium for energy, and no account is taken of the amount of heat necessary to develop or store the energy. " In order to get a comparative idea as to the relative values of liquid air and water for power storage, two similar cycles for water will be calculated, and comparative figures obtained. "The range of temperature in the cycle taken for air is from -312 to 70, or 382. " Starting with water and heating it to 504 under 700 Ibs. pressure absolute, and expanding it to 2 Ibs. pressure absolute and 126 Fahr., gives a range of temperature slightly less, viz., 378. The ratio of expansion will be 254. This final volume of 1 Ib. is 172 cub. ft., and considering the expansion to be hyperbolic, we have W = 288 x 173 x 5*59 = 280,000 ft.-lbs. 9&0 000 - = -1415 H.P. per pound of water used per hour, oO x o3,000 and = 7*08 Ibs. of water per horse-power per hour. "By heating the water to 546 under 1,000 Ibs. pressure and expanding to atmospheric pressure the range of temperature would be still less, or about 334. " The final volume would be 26-3 cub. ft. VERY LOW TEMPERATURES. 601 26-3 K . Katio or expansion - - = 5o. 60 x 33,000 1 1139 = 21-7 x 26-3 x 4-04 = 225,000 ft.-lbs. = '1139 H.P. per pound of water use = 8'8 Ibs. water per horse-power per hour. 225,000 n ! QO TT -D = 'Hoy ti.r. per pound or water used per hour. "From these figures it will be seen that under the conditions assumed water will give off from 20 per cent, to 50 per cent, more energy than liquid air, during expansion through equal temperature ranges. The possibility of the use of liquid air in a prime mover comes from the fact that the upper temperature limit for the range assumed is so low as compared with that for the steam. The upper limit for the air is at 70 Fahr. or 531 absolute, and the possible thermal efficiency is ff^ = -72 ; for the water the upper limit is 504 Fahr., or 965 Fahr., and the possible efficiency is fjf = '39. If the efficiency of the liquid is in any way comparable with that which can be gotten from steam in the steam engine, the efficiency of the air engine should be good. The cost of production of a pound of air would be much greater than that of a pound of steam, so that to be a commercial factor, the efficiency of the air engine would have to be much greater than that of the steam engine. Whether this can be accomplished the future alone must decide. "As to other uses, refrigeration, medical cautery, prevention of chemical action, explosive compounds, reduction of resistance of con- ductors for electricity, and use for prevention of the ill-effects of anaesthetics have been suggested, and others will doubtless develop as experiments are tried. It is only within a few months that the liquid could be obtained at a cost that allowed of trial of its properties for any except scientific purposes where no possible financial return was to be expected, and cost was a secondary consideration. With a large supply available, rapid development may be looked for, and new uses will be constantly discovered." APPENDIX BIBLIOGRAPHY OF REFRIGERATION BOOKS. ANDERSON, J. W. : "Refrigeration: an Elementary Text-book." Lon- don, 1908. BAENES, H. T. : "Ice Formation." New York. BEHREND, GOTTLIEB : " Eis und Kiilteerzeugungs Maschinen." Halle-a- Salle, 1888. BOYER, DICKERMAN : " Refrigeration." Chicago. COOPER, MADISON : " Eggs in Cold Storage." " Practical Cold Storage. Chicago. DERMINE, G. : " La Technique du Froid," translated from German of G. Lehnert. Paris, 1911. DOUGLAS, LOUDON M. : " Refrigeration in the Dairy." " Douglas' Encyclopaedia." London. " Encyclopaedia Britannica." London, 1911. EWING, J. A. : " The Mechanical Production of Cold." 1908. GIBBS, VON J. WILLARD : " Thermodynamische Studien." Leipzig. GOETTSCHE, VON GEORGE : "Die Kaltemaschinen." Hamburg. GUETH, OSWALD: "The Refrigerating Engineer's Pocket Manual." New York. HAUSBRAND, E, : " Evaporating, Condensing, and Cooling Apparatus." London. HEINEL, VON C. : "Bau- und Detrieb von Kalte-Maschinenanlargen." Miinchen. Hiscox, G. D. : " Compressed Air and its Applications." New York. ROLLER, THEODORE : " Die Kaelteindustrie." LEASK, A. RITCHIE : " Refrigerating Machinery and its Management." Second Edition. London. LEDOUX, M. : " Ice-Making Machines," with additions, by Messrs Denton, Jacobus, and Riesenberger. New York. 602 BIBLIOGRAPHY OF REFRIGERATION. 603 LESCARDE, F. : "L'CEuf de Poulesa Conservation par le Froid." Paris. LEVY, JOHN: "Refrigerating Memoranda." Chicago. LORENZ, HANS : " Neuere Kuehlmaschinen." Muenchen und Leipzig. LOVERDO, J. DE : " Le Froid Artificiel et ses Applications Industrielles, Commercial et Agricoles." Paris, 1906. "Abattoirs Publics." Paris, 1906. " Comptes Rendus, Rapports et Communications du Premier Congres International du Froid. Conservation par le Froid des Deurees Alimentaires." Paris, 1908. MARCHENA, R. E. DE : " Kompressions Kalte Maschinen." MARCHERRA, DE : "Machines Frigorifiques a Gaz Liquifiable." Paris. MARCHIS, L. : "Production et Utilisation du Froid." 1906. "Legons sur Le Froid Industriel." Paris. "Monographic sur 1'Etat Actuel du Froid en France." Paris, 1911. " Nelson's Encyclopaedia." Edinburgh. PAULDING, C. P. : " Transmission of Heat through Cold Storage Insula- tion." New York. PERRET, AUG. : " Les Machines a Glace et les Applications du Froid dans ITndustrie." PETIT, P., AND JACQUET, T. : " Machines Frigorifiques," translated from German of H. Lorenz. Paris, 1910. "Brasserie et Malterie." Paris, 1904. " Principles and Practice of Artificial Ice-Making and Refrigeration." Proceedings, American Warehousemen's Association. United States. Proceedings, Ice and Cold Storage Association. London. Proceedings, Institution Civil Engineers. London. Proceedings, Institution Mechanical Engineers. London. Proceedings, Institute of Marine Engineers. Stratford, London. Proceedings, Shipmasters' Society. London. Proceedings, Societe Nationale d* Agriculture de France. PRUDEN, T. M. : " Drinking Water and Ice Supplies." New York. REDWOOD, ILTYD J. : " Theoretical and Practical Ammonia Refrigera- tion." New York. RICHMOND, GEORGE : " Notes on the Refrigeration Process and its Place in Thermodynamics." New York. RITTER, FRIEDRICH : " Wasser und Eis." RUDDICK, J. A., Dairy and Cold Storage Commissioner, Department of Agriculture, Canada : " Reports to the Minister of Agriculture." SCHMIDT, L. M. : " Principles and Practice of Artificial Refrigeration." Philadelphia. SCHWARZ, ALOIS: "Die Eis und Kuehlmaschinen." Muenchen und Leipzig. 604 REFRIGERATION AND COLD STORAGE. SCHWARZ, OSCAR: "Public Abattoirs and Cattle Markets." Second Edition, edited by G. T. Harrap, A.M.I.C.E., and L. M. Douglas, A.M.I.M.E. SELFE, NORMAN, M.I.C.E. : " Machinery for Refrigeration." Chicago. SIEBEL, J. E. : " Compend of Mechanical Refrigeration." Eighth Edition. Chicago. SKINKLE, E. T. : " Practical Ice-Making and Refrigeration." Chicago. SPON'S " Dictionary of Engineering." London. SPON'S " Encyclopaedia." London. STETEPELD, RICHARD : " Die Eis und Kiilteerzeugungs Maschinen." Stuttgart. YOORHEES, GARDNER T. : "Indicating the Refrigerating Machine." Chicago. WALLIS-TAYLER, A. J., A.M.I.C.E. : " Refrigerating and Ice-Making Machinery." Third Edition. " Refrigeration, Cold Storage, and Ice-Making." Third Edition, 1911. "The Pocket Book of Re- frigeration and Ice-Making." Fifth Edition. London, 1911. WILLIAMS, HAL., A.M.I.M.E. : "Mechanical Refrigeration." London, 1903. WILDER, F. W. : " The Modern Packing House." WOOD, DE VOLSON : " Thermodynamics, Heat, Motors, and Refrigerat- ing Machines." New York. PERIODICAL PUBLICATIONS DEALING WHOLLY OR PARTLY WITH REFRIGERATION. Cold Storage. Monthly. London. Cold Storage. Monthly. New York. Eis- und Kiilte-Industrie. Bi-monthly. Berlin. La Revue Generale du Froid. "Power," Refrigeration Department. Weekly. New York. Proceedings, Ice and Cold Storage Association. " Practical Engineer " Pocket Book. Annually. Manchester. Ice and Cold Storage. Monthly. London. Ice and Cold Storage Trades Directory. Annually. London. Ice and Refrigeration. Monthly. New York. Ice Record. Monthly. Philadelphia. Ice Trade Journal. Monthly. New York. Le Froid, La Glace, et La Refrigeration. Monthly. Paris. Zeitschrift fur Eis. Bi-monthly. Lubeck. Zeitschrift fur die gesamte Kalte-Industrie. Monthly. Munich. INDEX A BSOLUTE pressure and tempera- /~\ ture, 9 - zero, 9, 10 Absorber for absorption machine, 177, 178, 183, 184, 185, 197 Absorption and binary absorption pro- cess, 174-210 machine, refrigeration by, 274 in butter works, 462 system, the, 20, 174-210, 274, 569, 570 Abstraction of heat by compressing air, 211-245 by evaporation of liquid to be cooled, 20, 25-33 by evaporation and mechanical compression of a separate refriger- ating agent, 20, 34-151 by evaporation and re-absorption of a separate refrigerating agent, 20 by the rapid dissolution of a solid, 20, 21-24 Abyssinian War, use of ether machine, 119 Accumulations of deposit in condenser, 549-551 Admiralty, cold-air machines supplied to, 415, 416 Admixture of sulphurous acid and car- bonic acid as a refrigerating agent, 45 Advantages of absorption system, 174, 175 of atmospheric condensers, 157 of carbonic acid machines for marine installations, 129, 397 claimed for Gobert system of con- structional congelation, 482 of cold-air blast system, 279 of cold-air system, 212 of Cooper system of mechanical air circulation, 325-328 of direct expansion system, 275 of double pipe condensers, 165 of ether as a refrigerating agent in hot climates, 44 Advantages of submerged condensers, 152 of using sealing and lubricating oil in ammonia compressors, 56, 57 of wall or plate system of ice-making, 496 of Yaryan apparatus for the produc- tion of distilled water, 512-517 After preservation of frozen meet, 272 Agent, liquefied arrangement for removal of, from condenser, 159, 160 or medium used in vacuum machines, 32, 33 Agitation, method of making clear crystal ice by, 485, 487-507 Air agitation system of making clear or crystal ice, 502 atmospheric, germs of fungus or mould in, 313 aqueous vapour held in suspension in, 573 circulation, means for improving, 315-319 of, in cold storage chambers, 313- 328, 431, 432 cold, machines, 20, 211-245, 272-274 cooler, or chamber, with corrugated brine battery, 292-295 degree of, saturation of, 572 determination of moisture in, 570-573 effect of presence of, 541 ejection of, from ammonia system, 539-540 instruments for measuring moisture in, 570, 571 presence of, in ammonia machine, to detect, 541 pressure, testing ammonia compressor under, 539, 540 - trunks, construction of, 271 value of, as in insulator, 330 Allen dense-air ice machine, 238-241 Allowances, per ton capacity, in refriger- ating machine, 286, 287, 457 America, number of firms directly inter- ested in refrigeration in, 7 605 6o6 INDEX. American absorption machine, 205-209 arrangement for removing liquefied agent from condenser, 159, 160 - for wort cooling, 446, 447 Engineer, relative heat conductivity of various materials, 336 ice-making machines, 22 practice as to the making of brine, 532-534 - Society of Mechanical Engineers, paper on regenerative method of producing very low temperatures, 593 Warehousemen's Association, table showing transmission of heat through various insulating structures, 345-350 Ammonia, advantages of, as a refriger- ating agent, 48 anhydrous, 49 boiling point and latent heat of, 48 manufacture of, 49, 50 anti-putrescent qualities of, 276 apparatus, leaks in, 559 composition of, 48 compression machines, arrangement of, in butter dairies, 425-429 management of, 539-578 marine types, 402-413 condensers, marine types, 401, 409 disadvantages of, as a refrigerating agent, 48-50 gas, difficulties of dealing with, 50 superheating of, 542 lubricating qualities of, 552 machines, 48-116 machine, most important part of, 50-56 of commerce, 49, 50 - properties of, 48 receiver and oil trap, 549 Amount of condenser surface required, 155, 157, 164 of cooling water required, 156, 157, 164 of refrigerating pipes necessary for chilling, storage, and freezing chambers, 280, 281 of refrigeration required in cold stores, 280 of water required in refrigerating apparatus, 570 Analyser for absorption machine, 182 Ancients, production of ice known to, 1 use of liquefaction by, for refrigerat- ing purposes, 21 Andreef formula of relation of specific gravity of sulphurous acid to tem- perature, 121 Andrews' experiments in liquefaction of Jases, 588 $ valve, 247 Anhydride, carbonic. See Carbonic acid Anhydrous ammonia, 49 boiling point and latent heat of, 48 manufacture of, 49, 50 sulphurous acid and carbonic acid refrigerating agent, 45 Antarctic, single-acting compressor, 108 Anti-putrescent properties of ammonia, Apparatus, ammonia, leaks in, 559 for de-aerating or distilling water, 508-517 for making distilled water from exhaust steam, 510 gravity, for lowering carcases, 380 Appendix, 602-604 Apples, cold storage of, 389 first cargo of, from Melbourne, 6 Appliances required in absorption system, 174, 175 Applications of refrigeration, construc- tional, 473-483 manufacturing, 439-473 Approximate allowances, per ton capacity, in refrigerating machine, 286, 287, 457 cost of operating ice factories, 586 of ice-making, 587 Aqueous vapour held in suspension in pure dry air, 573 Architectural aspects of cold stores, 285 Arctic cold-air machines, 211, 212, 234- 238 experiments with, 244 Machine Manufacturing Co. , ammonia compressors, 104 Areas. See Diameters, areas, and dis- placements Armitage, Mr H. T., regulating the fermentation of tea by refrigeration, 464 Armstrong, Lord, definition of heat by, 9 Arrangement for chilling and freezing on wall system, 292-294 for cooling fermenting rooms, 446-451 for increasing surface of cooling pipes, 268, 269, 292 for lifting ice cans, 523-529 for more even distribution of work of compressor piston, 105 for traversing carcasses through chilling and freezing rooms, 293 of air-cooling tower, 295-297 INDEX. 607 Arrangement of cold stores, internal, 285 of cooling pipes in bacon factories, 305,306 in ceiling lofts, 290 1 in cold stores, 280-284 on brine circulation system, 274, 275 of corrugated brine air-cooling battery, 294-295 - of piping in cold storage rooms, 280- 284, 313-328 of refrigerating plant in an hotel, 309- 312 Arrangements for making clear or crystal ice, miscellaneous, 499-508 of pump or piston agitators, 505-507 Articles, various proper temperatures for cold storage of, 381-395 Artificial butter factories, use of refriger- ating machinery in, 461-464 cold, use of, by Esthonian tribe, 21 currents of air, atmospheric con- densers cooled by, 161 ice, storage house for, 535 refrigeration in bacon curing works, 305, 306 origin of, 1 surfaces of ice, formation of, 473 Asbestos paper or cloth, value of, as an insulating material, 335 results of tests as to conductivities of, 334 use of, as an insulating material, 329 Ashantee campaigns, use of ether machine, 120 Asparagus, cold storage of, 391, 392 Atlas Company, Ltd., carbonic acid compressor, 149-151 Atmosphere of cold stores, 271, 272, 273, 277 of hospitals and large public buildings, cooling of, 472 Atmospheric surface condensers, 157-164. See also Condensers Attemporating in breweries, refrigerated water for, 444, 451-455 Auldjo Machine Co., compressor made by, 108 Australian apples, trade in, 6 Australia, use of pumice stone as an insu- lating material in, 329 Automatic electric beef hoist, 372-376 ice dump, 525-527 - Refrigerating Machine Co., ammonia compressor, 100 Auxiliary or separate absorber, 194 Aylesbury Dairy, vacuum machine at, 27 BABY compressor, A. H. Barber Manufacturing Co., Ill, 112 Back pressure, loss of efficiency in am- monia compressors from, 56 Bacon factories, arrangement of cooling pipes in, 305, 306 reasons for use of artificial refri- geration in, 306 Bait, freezing, 472 Ball, improvements in absorption machines, 197, 198 Balloons, use of refrigeration for purifica- tion of gas for inflation of, 472 Baltic, imports of butter from, 6 Bananas, transport of, from Jamaica, 3 Barber, A. H., Manufacturing Co., double-acting ammonia compressor, 108-111 plans for insulation, 365 small cold store and ice plant for hotel, 309, 310 single-acting ammonia com- pressor, 111, 112 Bar-box, cooling of, 209 Barges, refrigerated, 421 Barnard water- cooling tower, 170 Barrel, old, to make brine mixer of, 533 Baudelot cooler for breweries, 446, 447 Bavarian engineers, tests of Linde com- pression machine by committee of, 80, 81 Bayswater, vacuum machine at, 27 Beck, William Henry, improvements in absorption machines, 175, 184 Becks, G. A., experiments on heat con- ductivity of slag wool and charcoal, 342, 343 Beef chill-room fitted with Haslam patent brine-cooling battery, 301-303 fitted with the De La Vergne patent pipe system, 298-301 hoist, automatic, electrically operated, 372-376 Beer wort, refrigeration of, 444-446 Beffa, Delia, & West, ether machine, 42 Belgian dairies, type of cream cooler used in, 431 Bell-Coleman cold-air machine, 221, 222, 243, 244 freezing machine, tests to determine best covering for, 336 Berryman system of making ice, 502-504 Bibliography of refrigeration, 602-604 Binary absorption process, 209, 210 Black currants, cold storage of, 389 Black, Dr, discovery of latent heat by, 10 Blast, cold-air s-yst 6o8 INDEX. Blast furnaces, use of refrigeration in, 465-469 Bleaching of clothes by refrigeration, 472 Block, Louis, improvements in ammonia compressors, 57, 58 Blowers, use of, for cooling atmospheric condensers, 161 Blythe & Southby, improved vacuum machine, 31, 32 Board of Trade instructions to surveyors re carbonic acid machines, 397 Boiler- covering materials, heat conduc- tivity of, 340 feeding purposes, use of waste con- densation water for, 168 Boiling point, latent heat, &c., of anhy- drous ammonia, 48 Books on refrigeration, 602-604 Borsig, A., sulphurous acid machines, 129 Bottles containing anhydrous ammonia, warming when charging machine from, 540 desirability of keeping in cool place, 541 Box & Lightfoot, table of aqueous vapour held in suspension in air, 573 Box radiation through walls, 288 Boyle, Mr David, pioneer of refrigerating machinery, 97 modern type of ammonia com- pressor, 97 Boyle's or Marriotte's law, 18 Bramwell, Sir Frederick, on Perkin's compression machine, 34 Breaking joints in ammonia machines, 551, 552 machinery, ice, 537, 538 Breweries, cubic feet of space per running foot of 2-in. piping, 281 - refrigeration in, 444-458 rough estimate of refrigeration in, 457 Brewery, ammonia pumps or compressor for, 86, 87 Brick surfaces, waterproof coatings for, 345-350 Bridge, Messrs David, & Co. , ice crushing or breaking machinery, 537, 538 Brine, forming of, 492 circulation system, arrangement of cooling pipes on, 274, 275, 313-328 of refrigeration, 274-275 objections to, 279 in breweries, 446, 447, 448 cold, passing air through body of, 297 concentrator, 534 cooling battery for cooling air, 295- 297 Brine for use in refrigerating and ice- making plants, 532-534 mixing tank, 532, 533 strainer, 533 British Government, use of refrigerating machines by, 119, 120 Humboldt. See Humboldt Broadbent, Mr J. C., rotary chocolate cooler, 443, 444 Brompton, vacuum machine at, 27 Bronze alloy, use of, in compressor cylinder, 143 Brotherhood's refrigerator, 445 Buffalo Refrigerating Machine Co., am- monia compressor, 102-104 "Bulletin de la Societe de 1'Industrie Minerale," Poetsch process, 422- 438 Bureau, U.S. Weather, saturation of air, 572 Burnand ice refrigerating machine, 436, 437 Butter, artificial use of refrigeration in factories of, 461-464 - brought over from Denmark, 6 imports of, 6 manufactories and dairies, refrigera- tion in, 422-438 preservation of, by refrigeration, 385 CABBAGE, cold storage of, 391, 392 \_^ Cailletet, experiments in liquefac- tion of gases, 588 Calahan suction valve, 260 Calculations made with respect to heat, 11-19 " Campania," refrigeration of cargo holds on board of, 409-411 of provision store on board of, 411- 413 Campbell. See Westerlin and Campbell Canada, imports of butter and cheese from, 6 Canadian apples, trade in, 6 Canadian Farming World, article on filling ice houses, 535 Candle and paraffin oil works, refrigera- tion in, 459-461 Can hoist for small plants, 525 system of ice-making, 487-492 objectionable features of, 488- 490 Cans or moulds, ice, 27 Canvas saturated with cold brine, cool- ing air with, 297 Capacities, refrigerating, table of, 284 Capacity of machine required for refri- geration of cold chamber, 286, 287 INDEX. 609 Capacity of refrigerating machine, dia- gram showing variations in, 277 Capillary cream cooler, 431 Carafes, arrangement for freezing, 309 frappes, production of, 27 Carbon dioxide. See Carbonic acid Carbonic acid, advantages of, 47 and sulphurous acid refrigerating agent, 45 composition of, 129 compressors, 45, 46 disadvantages of, 47 machine, 45-47 consumption of water in, 142 leaks in, 560 marine types, 396-401 to charge and work, 554-556 properties of, 45-47 - solidification of gas, 129, 130 anhydride. See Carbonic acid Carcasses, freezing of, for transport, 270- 272 imports of frozen, 2-4 - packing, in cold rooms, 271, 286 storing, on board ship, 417, 418 Carcass hoists, 372-380 Cards. See Diagrams Cargo of apples, first, from Melbourne, 3 of frozen meat, first, 2 of fruit, storage of, 419 Carpets, preservation of, by refrigera- tion, 472 Carre, Edmond, sulphuric acid machines, 27 Ferdinand, absorption machine, 174, 175-179 hand power ice machine, 33 Carrots, cold storage of, 391, 392 Cars, refrigerated. See Vans Cascade system of producing very low temperatures^ 588-592 Case Refrigerating Machine Co.'s am- monia compression machines, 108 Catamba grapes, cold storage of, 388 Cattle, live, cooling holds of vessels for, 473 Ceiling lofts, cooling pipes in, 290-292 Ceilings for cold stores and ice houses, 356, 357 Celery, cold storage of, 391, 392 Cell ice-making boxes or tanks, 496- 499 Centigrade thermometrical scale, zero on, 12 Challoner, Sons, & Co., Geo., ammonia compressor, 104, 105 Chambers. See Cold storage chambers Charcoal, consistency for packing insulat- ing spaces with, 330 39 Charge and work carbonic acid machine, to, 554-556 Charging an ammonia machine, 540, 541 Charles' law of expansion of gases, 12, 13 Chart applicable to any value of n, con- struction of, 14-16 Chatwood electrical thermometer, 575, 576 Cheese, imports of, from Canada, 16 refrigeration of, 386 Chemical process of refrigeration, the, 20, 21-24 works, use of refrigeration in, 472 Cherries, cold storage of, 389 Chew, Mr Leuig, submerged condenser, 154 Chief danger of deterioration of frozen meat, 6 - features to be looked for in an air- cooling tower, 157, 158 Childs, J. G., & Co., Ltd., automatic electric beef hoist, 372-376 mutton hoist, 376 Chilled beef, imports of, 3 Chilling, amount of refrigerating pipes necessary for, 280 or freezing on wall system, 292, 293 Chill-room, bacon, with side and ceiling cooling pipes, 303-306 - beef, cooled by brine air-cooling battery, 301-303 fitted with patent pipe system, 298-303 Chimogene, use of, as a refrigerating agent, 44 Chloride, methyl, properties of, 120 of sodium, brine made from, 274 Chocolate, cold slabs or tables for manu- facture of, 193, 194 cooler, rotary, 443, 444 cooling by cold air, 442, 443 - Enock & Co., Ltd., 440-442 first application of refrigerating machine to, 440 manufacture, use of refrigeration in, 440-444 Choice of agent for refrigerating pur- poses, 35-37 Choking up or freezing of compression system, 557, 558 Christiansen, Adolph Gothard, improve- ments in absorption machines, 175, 184, 185 See also Mackay and Christiansen Circulation, methods of piping that hinder air, 313-316 of air in cold storage chambers, 313-328 Citron. See Citrus fruits 6io INDEX. Citrus fruits, cold storage of, 388 Clark, Mr D. K., report on experiments with non-conducting substances, 336 Classification of refrigerating machinery, 20 Clausius, definition of heat by, 9 Clearances in | : ammonia compressors, '-^53-56 Clear or crystal ice, arrangements for making, 485-508 Cleveland, Ohio, Twining's compression machine in, 37, 38 Clothes, white bleaching of, by refrigera- tion, 472 Cloth, hard-pressed asbestos, value of, as an insulating material, 335 Clouet, experiments by, in liquefaction of gases, 588 Coal ashes, use of, for insulating pur- poses, 329 consumption of, by cold-air machines, 273, 274 Coating of ice on direct expansion pipes, 560 Coatings for brick surfaces, waterproof, 345-350 Cochran Co., carbonic acid com- pressor, 149 Cocks and valves, 246-269 expansion or regulating, 53, 246- 252 stop, 252-256 suction and discharge, 256-260 Coil bend, evaporating, 265-267 Coils defrosting of refrigerating, 560, 561 of pipe in submerged condenser, dimensions of, 155-157 Coke, use of, for charging air-cooling tower, 296 Cold air blast system, the, 279-280 machines, 20, 211-245, 272-274 advantages of, 212 for marine work, 414-417 - marine types, 396-421 modern patterns of, 416 . proper management of, 562 pumps of, 211 refrigeration, by, 270-274 system, the, 211-245 trunk for marine installations, 416, 417 brine, passing air through body of, 297 rooms or chambers, construction of, 285-364 packing of carcasses in, 286 - simple method of producing, in hot climates, 25 Cold slabs or tables for the manufacture of chocolate, 193, 194 storage chambers, circulation of air in, 313-328, 417 - temperatures for, 392-395 - ventilation of, 312, 313 cubic feet of space per running foot of 2-in. piping, 281 space, inspection of, 417 270-328 - stores, ceilings for, 356, 357 divisional partitions for, 353, 354, 355, 356 - flooring for, 355, 356 lighting of, 576-578 in United Kingdom, 7 piping for, 280-284 - ventilating shafts for, 312 walls for, 350-354 - various manufacturing, &c., applica- tions, 439-483 Coleman, C. J.; improved absorption machine, 203-205 J. J., experiments by, on heat con- ductivities of substances, 335, 336 - See Bell-Coleman Cole, Messrs T. & W., Ltd., chocolate cooling, 442, 443 cold-air machine, 211, 212, 244 marine, 417 Collectors or oil separators, 76, 509, 510, 544-549 " Colliery Manager's Handbook," Gobert congelation method, 477-483 shafts, application of refrigeration to sinking of, 472, 474-483 Collins, Mr W. Hepworth, on evapora- tive values of various substances, 336 Colyer, Frederick, C.E., results obtained with ether machine, 43, 44 - on working of absorption machine, 579, 580 Combined refrigerating and ice-making tank, 507 - utilisation of cold air and brine for cooling, 292 Common ammonia of commerce, 49, 50 salt. See Chloride of sodium Compensating chamber for stuffing box, 85 Complete discharge of gas from com- pressor cylinder, to ensure, 53, 54 installation of ammonia plant on the De La Vergne system, 59-62 small brewery fitted with refriger- ating plant, 458 Composition of freezing mixtures, 24 INDEX. 611 Composition of fossil meal, use of, for in- sulating purposes, 329, 330 kieselguhr, use of, for insulating purposes, 329, 334, 335 victuals, 383 Compound ammonia compressors, 93-99, 398, 407 compressor, Haslam marine type, 406, 407 Linde marine type, 403 single-acting marine type, 402 submerged condensers, 154, 155 Compression head, safety, 69, 70 heat generated by, misleading phrase, 16, 17 machine, refrigeration by means of, 274 machines, ammonia, cycle of opera- tion in, 52 main parts comprised in all, 20, 34-36, 37 - process, the, 18, 20, 34-151. See also Compression system side of ammonia machines, 52 system, choking up or freezing of, 557, 558 the, 20 Compressor, connection of oil separator to, so that oil can be used over again, 549 diagrams, interpretation of, 566-569 piston rod packings, 552-554 safety crosshead for, 71, 72 Compressors, ammonia, 51-116, 402-413 carbonic acid, 45, 46 double-acting, 51 ether, 34-44 methyl chloride, 120 methylic ether, 40 safety spiing heads for, 66-74 single-acting, advantages of, 51 disadvantages of, 51 sulphurous acid, 120-129 Condensation side of ammonia machines, 52 Condensed ammonia, to prevent loss of efficiency by heating of, 543, 544 water cooler and oil separator, 509 Condenser, accumulations of deposit in, 549-551 atmospheric, condensing surface re- quired, 155-157 cooling water required, 142, 156, 157 _ for, 168-173, 543 distribution of cooling water, 157, 158 Hall, 134 incrustation, 560, 561 marine type, 408-409 Condenser preventing spluttering of cooling water, 158, 159 removing liquefied agent from, 159, 160 usual dimensions of, 164 Condensers, ammonia, marine type, 401, 409-411 87, 120, 127, 128, 132, 133, 134, 135, 138, 146, 149, 151, 152-168, 401, 409- 411 Condensing pressure, use of, for ascer- taining whether apparatus is fully charged, 564, 565 .surface for atmospheric condensers, amount required, 1 64 for submerged condensers, amount required, 155-157 Conductivity of various substances, ex- periments on, 330-345 Confectionery, cold slabs or tables for the manufacture of, 193, 194 Congealing tanks, marine, 418 Connections. See Flange unions Conroy. See Douglas and Conroy Consistency for packing insulating spaces, Constructional applications of refrigera- tion, 439, 440, 473-483 Construction of ammonia gas com- pressors, 51-56 and arrangement of cold stores, 285 Consumption of water in sulphuric acid machines, 28, 29 See also Coal consumption Continent, number of firms directly inter- ested in refrigeration on, 7 Continuous-acting absorption machine, 175 Conveying machinery, ice, 520-529 See also Hoisting arid conveying machinery Coolers for cold-air machines, 220, 222 - Baudelot, 446, 447 Cooling air, arrangements for, 292-328 - battery, corrugated brine, 292-294 fermenting rooms, 446-451 pipes, arrangement of, in ceiling lofts, 303, 318, 319 on brine circulation system, 274, 275, 289, 290 surface of pipes, means for increasing, 268, 269, 292 towers, water, 168-173 - water, formula for calculating amount required in submerged condensers, 156 - for condenser, 168-173, 543 in separator jacket, 542 to economise, 168 612 INDEX. Cooper, Madison, arrangement for wash- ing, cooling, and drying air, 297, 298 correct relative humidity for a given temperature in egg rooms, 387, 388 on air circulation in cold storage chambers, 313-328 on cold storage of eggs, 297, 298, 387, 388 system of mechanical air circulation, advantages of, 328 Corliss engine for driving ammonia com- pressor, 81, 110, 114 Correct relative humidity for a given temperature in egg rooms, 387, 388 Corrosion of cooling pipes, protection of, from, 276, 277 Cost of ice-making, approximate, 587 of operating ice factories, approxi- mate, 586 of working refrigerating machinery, 579-587 Cotton wool. See Slag wool Coupon system of selling and delivering ice, 536, 537 Courrieres, use of refrigeration for shaft sinking at, 475 CracknelPs patent absorption machine, 198-200 Crane with long jib for raising carcasses from barges into cold stores, 378 Cream coolers, 430, 431 trade in frozen, 6 Creamery Package Manufacturing Co., ammonia compressor, 105, 106 - refrigerators, 431-436 Creams, freezing, ice, 309 Crescent or semi -cylindrical door for cold storage rooms, 310-312 Crosshead, safety, for compressors, 71, 72 Crushing or breaking machinery, ice, 537, 538 Crystal ice. See Clear ice Cube ice, 530 Cubic feet of ammonia gas per minute to produce one ton of refrigeration per day, 278 of space per running foot of 2-in. piping, 281 ice, 530 Cullen, Dr, experiments with ether, 34 vacuum machine, 26 Currants, cold storage of, 389, 393 Curve PV?i = constant, to construct, 14, 15 Cycle of operations in compression machines, 35-37 Cylinder system creamery refrigerator 433 Cylindrical oil separators or collectors, 545-548 Cyrogene, use of, as a refrigerating agent, 44 DAIRIES, refrigeration in, 422-438 Davy, Sir Humphry, definition of heat by, 8 Dead bodies, preservation of, by refrigera- tion, 391 weight safety valve, 144 De-aerated water, making clear ice with, 485 De-aerating or distilling apparatus, 508- 517 Definition of latent heat, 10 of specific heat, 10 Definitions of heat, various, 8-10 Defrosting of refrigerating coils, 560, 561 Dehydrator. See Drier De La Vergne arrangement for cooling in brewery, 448-450 atmospheric condenser, 153 disc or gill for cooling pipes, 268, 269 expansion cock, 247, 148 installation at skating rink, 473 installations on "Campania" and "Lucania," 411-413 marine types of ammonia machines, 402 oil separator or collector, 76, 544, 545 -- patent pipe system, 268, 269, 298-301 safety suction valve, 260 - stop-cock, 252, 253 type of ammonia compressor, 56-66 - of pipe joint, 261, 262, 265 Delion and Lepen, sulphurous acid ma- chine, 129 Delia Beffa and West ether machine, 42 De Mairan, specific gravity of ice, 484 De Motay and Rossi absorption machine, 210 Denmark, butter brought over from, 6 Dense air machine, 228-241 Denton, Professor, losses in compressors, 91 Deposit in condenser, accumulations of, 549-551 Deterioration of frozen meat, chief dangers of, 6 Determination of moisture in air, 570- 573 Dewar, Professor, production of liquid air, 590, 591, 592 INDEX. Dewar, Professor, use of ethylene as an agent, 590 vacuum flask, 591 Diagrams from "Arctic" cold-air ma- chine, 237, 238 Frick compressors, 70, 71 interpretation of compressor, 566-569 Diagram showing variations in capacity of refrigerating machine, 277 taken from double-acting compressor, with sealing oil, 64, 66 single-acting compressor, with- out sealing oil, 63, 64 single-acting compressor, with sealing oil, 64, 66 Diameter and stroke, ratio between, in ammonia compressors, 54-56 Dickerson, Mr Walter, on physical con- stants of liquefied gases, 599-601 Dimensions of submerged condensers, 155-157 Direct expansion, cooling brewery fer- menting room by, 448 making ice by, 486 pipes, effect of a coating of ice on, 560 - - system, 275-279 Disadvantages of cold-air system, 211 cold-air blast sj^stem, 279 Discharge of gas from compressor, to effect complete, 53, 54 valves. See Suction and discharge valves Discs or gills for cooling pipes, 268, 269 rotating, cooling air with, 297 Dissolution of a solid, abstraction of heat by, 20 Distillation of anhydrous ammonia, 49, 50 Distilling. See De-aerating machine, methylic ether, 40 Distinctive feature of the Yaryan evapo- rator, 513 Distinct meanings of heat and tempera- ture, 10 Distributing valve. See Expansion valve Distribution of water in atmospheric condenser, 158, 159 of work of compressor piston, 105 Divisional partitions for cold stores, 353, 354 Dobbie, John G., tests by, to determine conductivity of asbestos and Kie- selghur composition, 334, 335 Donaldson, H. F., lifts designed by, 378- 380 non-conductive values of different materials, 337, 338 Door insulation, 357-360 Door, rotary, 310-312 - wedge, 357 Dortch. See Suppes and Dortch Douane, Messrs, methyl chloride com- pression machines, 120 Douane, Mr M. E. See Douane, Messrs Double-acting compressor and tandem compound condensing steam engine, 90 compressors, advantages of, 51 disadvantages of, 51 compressor stuffing boxes, packing for, 553 De La Vergne ammonia com- pressor, 56-66 Kilbourn horizontal ammonia com- pression machine, 408 effect water-distilling apparatus, 516 - pipe condensers, 165 Douglas and Conroy patent sulphurous acid compressor, 124-128 Douglas, Messrs Wm., & Sons, Ltd., air- cooling apparatus, 295-297 sulphurous acid compressor, 124- 128 Mr Loudon, on dairy refrigeration, 422 Mr T., apparatus for cooling air, 295- 297 Dourges, use of refrigeration for sinking shafts at, 475 Drawbacks to wall or plate system of ice- making, 495 Drier or dehydrator of ammonia still, lime in, 50 Drip trays for cooling pipes, 298, 305 Drop valve steam engine for driving compressor, 94 Dry air refrigerator, 242 system of working ammonia com- pression machines, 52, 53 Drying, cooling, and washing air, appar- atus for, 297, 298 Dual absorption system, 209, 210 Duplex marine type of carbonic acid machines, 398-401 Duterne, Victor, metallic packing, 478 Dynamics, thermo, first lesson of, 8-19 Dynamite factories, refrigeration in, 471 EARLY investigators and experi- menters in the production of very low temperatures, 588-592 Eclipse atmospheric condenser, 158 can ice-making box, 488 system, plan of ice factory on, 520, 526 614 INDEX. Economiser or temperature exchanger, 181, 197 Economy of direct expansion system, 275 of multiple effect distilling apparatus, 512 Effective surface of cooling pipes, to increase, 268, 269 effect of a coating of ice on direct ex- pansion pipes, 560 Efficiencies of ice plants, 531 Efficiency, loss of, in ammonia compres- sors, 56 of refrigerating machines, greatest theoretical, 17 of submerged condenser, to ensure utmost, 154 principal qualities to be sought for in compressor to ensure maximum, 53-56 water-cooling apparatus, 170 Egg rooms, correct relative humidity in, 387, 388 Eggs, cold storage of, 297, 298, 386-388 Egypt, use of ether machine during mili- tary operations in, 120 Elder, Dempster, & Co., transport of bananas from Jamaica by, 3 Electrically driven ammonia compressor, 110, 111, 413 compressor on railway van, 371 operated beef hoist, 372-376 mutton hoist, 377 thermometer or telethermometer, 575, 576 heated absorption machine, 203-205 Electrical temperature tell-tales and long- distance thermometers, 573, 574 welding of condenser and evaporator coils, 135 Electric fans, use of, for circulating air, 319, 320 - welding, 135 Elevating and conveying machinery, ice, 520-529 Elevators or hoists, ice, 527-529 Emery, Charles E., experiments with non-conductors of heat, 335 Enclosed compressors. See Inclosed Endless travelling band or apron choco- late-cooling apparatus, 444 Engineer, description of Poetsch method in, 475 Engineering, non-heat-conducting pro- perties of various substances, 341 Engine-room of steamships, location of carbonic acid machines in, 397 Enock, Arthur G., safety device for com- pressors, 71, 72 Enock compressors, 71-79 marine type, 413 milk-cooling plant, 423-425 on proper temperature for storing butter, 438 Equation expressing greatest theoretical efficiency of a refrigerating machine, 17 Equivalent of a ton of ice, 484 of heat, mechanical, 11, 18 Escher, Wyss, et Cie, carbonic acid machine, 151 Esthonian tribe, use of artificial cold by, 21 Estimate of refrigeration required in breweries, 437 Ether, advantages of, as an agent in hot climates, 44 composition of, 117 compression machines, 34-44, 117-120 experiments with, by Dr Cullen, 34 machine at brewery, first, 439 cost of working, 582, 583 methylic, distilling machine, 40 objections to the use of, as a refriger- ating agent, 44 - properties of, 117 Evaporating coil bend, 265-267 Evaporative surface condensers, 157-164 Evaporator, care of, 517 Evaporators, 87, 91, 135, 155 Even distribution of work of compressor, arrangement for, 105 Ewing, Professor, on cascade or successive cycle system, 589, 590 on regenerative method, 592 Exchanger, heat. See Economiser Exhaust steam, apparatus for making distilled water from, 510 Exhibition, Paris, carbonic acid com- pressor in brewery section, 151 Expansion, direct, economy of, 275 of gases, laws of, 12 side of ammonia compression machines, 52 - system, the, 275-279 - valve for methylic ether machine, 42 valves and cocks, adjustment of, 53 various, 246-252 Experiments by Dr Cullen with ether, 34 - on the transmission of heat, 344, 345 with cold-air machines, 244 with non-conducting substances, 330- 345 Express Dairy, milk-cooling installation at, 425-428 External carcass hoist, 376-378 Extreme limits of space per foot of piping, 281 INDEX. 615 FACTORIES, artificial butter, 461-464 bacon, 305, 306 ice, 518-529 sugar, 464, 465 - tea, 464 Fahrenheit, thermometrical scale, zero on, 12 Fans or blowers for cooling atmospheric condensers, 161 use of, for circulating air in cold stores, 319-328 Faraday, Professor, experiments in lique- faction of gases, 588 Feathering agitators, 488 Features, chief, to be looked for in water- cooling tower, 170 Fermenting rooms, cooling of, 446-450, 464 Film evaporation, 513 Firms directly interested in refrigeration, number of, 7 First cargo of apples from Melbourne, 6 class ether machine, results obtained with, 43 compression machine, 34 law of thermo-dynamics, 8 Fish, cold storage of, 383-385 freezing, cubic feet of space per running foot of 2-in. piping, 281 Fixary ammonia compressor, 83, 84 - air coolers, 303 Flange unions or connections, 264, 265 Flash valve. See Expansion valve Flasks of C0 2 , warming when charging machine from, 554 Flasks, vacuum, for liquid air, 591 Flat plates for air-cooling batteries, 292, 293 Flines les Raches, use of refrigeration for sinking shafts at, 475 Flooring for cold stores, 355, 356 ice houses, 356 Floors of cold stores, radiation of heat through, 288 Fluorine, liquefaction of, 592 Fontaine. See Mollet, Fontaine, et Cie Fontinette canal lift, use of refrigeration in construction of, 476 Forbidden fruit, cold storage of, 388 Forced air circulation, 319-328 Forecoolers. See Supplementary con- densers Formula for ascertaining amount of air delivered by cold-air machine, 245 calculating amount of cooling water for submerged condensers, 156, 157 dimensions of submerged con- densers, 155, 156 Foundations, application of refrigeration to the construction of, 473 France, simple method of making ice, used in, 25 use of cork in, as a non-conductor, 329 Freezing chambers, amount of refrigerat- ing pipes necessary for, 280 - fish, method of, 383, 384 mixtures, table of, 24 or choking up of compression system, 557, 558 times for different temperatures and thicknesses of can ice, 491 water slowly, at comparatively high temperatures, 485 French absorption machine, 193, 209 brewery section of Paris Exhibition, carbonic acid compressor at, 151 Fresh provisions, trade in, 1-7 Frick ammonia compression machine, 66-71 Co., apparatus for making distilled water, 510 arrangement for cooling brewery fermenting rooms, 451 Baudelot cooling apparatus, 446, 447 brine strainer, 491 can ice-making box, 488 cost of operating ice factories, 586 ice-can hoist, 525 pattern of suction valve, 260 plans for ice factories, 520 plans for insulation, 365 stop-valves, 254 truck in can hoist, 525 pipe joints, 265-268 Frigorific mixtures, general law govern- ing production of cold by, 23 observations on, 23 See also Freezing mixtures Frozen beef, imports of, from New South Wales, 3 imports of, from New Zealand, 3 carcasses, imports of, 2-4 cream, trade in, 6 - meat, trade in, 2 mutton, hanging of, before cooking, 286 Fruit cargo, proper stowage of, 418, 419 trees, regulation of, by refrigeration, 472 Fruits, cold storage of, 388-390, 410, 419 Fry, J. S., use of cold air for chocolate- cooling by, 440 Function of refrigerating and ice-making apparatus, main, 19 6i6 INDEX. Fungus or mould, germs of, in atmos- pheric air, 313 Furnaces, blast, use of refrigeration in, 465-469 Furniture, upholstered, preservation of, by refrigeration, 472 Furs, preservation of, by refrigeration, 391, 472, 473 Gravity air circulation in cold rooms or chambers, 314-319 apparatus for lowering carcasses, 380 Greatest theoretical efficiency of a re- frigerating machine, 17 Great Southern and Western Railway, Ireland, refrigerator car, 367 Green vegetables, cold storage of, 390 GALE, ARTHUR ROBERT, paper on refrigerating machine, 241-243 Gas, ammonia, difficulties of dealing with, 50 compressor, most important part of compression apparatus, 50, 57 for balloons, use of refrigeration for purification of, 472 motor, advantages of, for driving small refrigerating machines, 307, 308 Gases, Charles' law of expansion of, 12 laws of, 12-14 liquefaction of, 588-601 Lussac's law of expansion of, 12 Gasoline, use of, as a refrigerating agent, 44 Gasworks breeze, use of, for insulating purposes, 329 Gay, C. M., arrangement for circulating air, 318 General law governing production of cold by frigorific mixtures, 23 Generator for absorption machine, 171, 174, 185, 193, 204, 209, 210 Germany, use of cork in, as a non- conductor, 329 Germs of fungus or mould in atmospheric air, 313 Giffard cold-air machine, 215, 222-224, 244 Gill, pipe, 268, 269 Gland of carbonic acid machine, to pack, 556 Globe expansion valve, 247 Gobert method of using refrigeration for constructional work, 477-483 Godell, Henry Carr, use of lampblack as an insulating material, 330 Gorman improvements in absorption machines, 193 Gorrie, cold-air machine, 214 Gothenburg, milk shipped to London from, 6 Gottbrecht, Dr, experiments on pro- perties of ammonia, 276 Grapes, cold storage of, 388, 389, 394 trade in, 6 HABRIER, experiments in lique- faction of gases, 588 Hainault coalfield, refrigeration for shaft- sinking at, 475 Hair-felt, use of, for insulating purposes, 329 Hall, cold-air machines, 233, 234, 292, 293 J. & E., Ltd., carbonic acid com- pression machines, 131-141 cold-air machines, marine types, 415, 416 duplex horizontal carbonic acid compressor, 139-141 marine types of carbonic acid machines, 397-401 plan for chilling and freezing on wall system, 294, 295 small vertical self-contained car- bonic acid machine, 132-138 single-cylinder double-acting hori- zontal carbonic acid compressor, 138 steamers fitted with refrigerating machinery for the butter trade, 6 to charge and work carbonic acid machine of, 554-556 system for cooling milk, 425-428 Hampson, production of liquid air by, 593, 595-599 Hanbury. See Truman, Hanbury, & Co. Handling ice, 536, 537 Hand-power ice-making machine, 33 Hargreaves and Inglis cold-air machine, See also Hick Hargreaves Harrison ether machine, 2, 38-40 erected at brewery, first, 439 in paraffin works, 439 James, ether compression machine, 38 improved vacuum apparatus, 29-31 vacuum machine, cost of making ice with, 584 See also Twining and Harrison Haslam air agitation ice plant, 502 ammonia valves, 256 atmospheric or open-air evaporative surface condenser, 160 - beef chilling room fitted with patent brine-cooling batteries, 301-303 blast furnace installation, 466-469 INDEX. 617 Haslam brine concentrator, 534 carbonic acid compressors, 149-151 cold-air machines, 225-230, 244, 415 at London and St Katherine Dock, 272-274 for marine work, 415 cold storage chamber, small, 306-308 distilling apparatus, 512 formula for ascertaining amount of air delivered by cold-air machine, 245 - Foundry and Engineering Co., Ltd., marine types of ammonia com- pressors, 97, 404-407 open water cooler, 168 Sir Alfred Scale, apparatus for cooling air, 294, 295, 420, 421 improvements in ammonia com- pressors, 93-97 water-cooling tower, 173 Head, safety compression, 66-79 Healthy working of ammonia machine, signs of, 541 Heat and temperature, distinct meanings of, 10 calculations made in respect of, 11-19 conducting power of various sub- stances, slate being 1,000, 342 definitions of, 8-10 discovery of, 8 exchanger. See Temperature ex- changer generated by compression, misleading nature of phrase, 16 - latent, 10, 11 mechanical equivalent of, 11, 18 pump, refrigerating, machine, a, 19 sensible, 10 - specific, 10 and composition of victuals, 383 "Heating by Hot Water," experiments regarding heat-conducting properties of various substances, 341 Hendrick's condenser, 165-168 Henry Vogt Machine Co., absorption machine, 196, 197 Hercules discharge and suction valve, 259 Ice-making and Refrigerating Ma- chinery Co., ammonia compressor, 106-108 Hick Hargreaves, cold-air machine, 224, 225 Hickmann, Ltd., refrigerating installa- tion, 466-469 Hill, F. B., arrangement of cold store or chamber, 290-292 arrangement for removing snow or hoar frost from refrigerating sur- faces, 292 Hill and Gorman, improvements in ab- sorption machines, 193 and Sinclair, improvements in absorp- tion machines, 193 - Frederick Barker, improvements in absorption machines, 193, 194-196 method of making clear or crystal ice, 499-502 History of trade in frozen meat, 2, 3 of fresh provision, 1-7 Hoar frost, removal of, from refrigerating surfaces, 292 Hoisting and conveying machinery, 372- 380 Hoists. See Elevators or Hoists Holden system of ice-making, 507, 508 Holds of vessels, cooling of, 473 Hollow or semi-cylindrical door for cold storage chamber, 310-312 Hopkinson, Dr, on cost of making ice with Windhausen machine, 583, 584 description of Windhausen machine, 27-29 Hops, cold storage for preservation of, 456 Horizontal duplex marine type carbonic acid machines, 398-401 pipe, mercury well for, 563 Hospitals, cooling of atmosphere of, in warm climates, 472 Hot beer wort, refrigeration of, 444-446 climates, simple methods of pro- ducing cold in, 25 Hotel, arrangement of refrigerating plant in, 309-312 Houses, ice, ceilings for, 356, 357 floorings for, 356 Houssu coalfields, use of refrigeration for sinking shafts at, 475, 476 Hubner. See Wegelin and Hubner Humboldt, ammonia compressor, 83 sulphurous anhydride compressor, 129 carbonic acid compressor, 149 meat-cooling plant, 303 milk-cooling arrangement, 428 Humidity, correct relative, for a given temperature in egg rooms, 387, 388 Hydrants, advisability for provision of, in ice factory, 530 Hygrometers, 571 T CE and Cold Machine Co. , absorption I machine, 197, 198 and refrigeration, articles on circula- tion of air in cold storage chambers, 313-328 apparatus for manufacture of, 62 can hoist for small plants, 525 6i8 INDEX. Ice cans or moulds, 27 crushing or breaking machinery, 537, 538 cube, 530 dump, automatic, 525-527 effect of a coating of, on expansion pipes, 560 elevating and conveying machinery, 520-529 - factories, 518-529 advisability for provision of hydrants in, 530 approximate cost of operating, 586 houses, ceilings for, 356, 357 flooring for, 356 making, 484-538 cost of, 579-587 in breweries, 457, 458 machine, American, 22 machines, management of, 539-578 testing of, 562-566 or congealing tanks, marine, 416, 417, 418, 419 vacuum system of ice-making, 517, 518 various methods of, 485 packing, 535-537 properties of, 484 stores, refrigeration of, 535 ventilation of, 535 tanks and refrigerator combined, Pictet's, 45 water. See Attemperating Ideal Refrigerating and Manufacturing Co., ammonia compressor, 105 Illinois Central Railway, refrigerator car on, 368-370 Imitation of natural system of ice-making, 518 Imperfections of first absorption ma- chines, 174, 175 Important part of ammonia machine, most, 50-56 Imports of butter, 6 of cheese, 6 of chilled beef, 3, 5 of frozen carcasses, 3, 4 Improved Carre hand-power ice machine, 32 Improving air circulation, means for, 327, 328 Inclosed types of ammonia compressors, 73-77, 87, 114-116 Increase the effective surface of cooling pipes, to, 268, 269 Incrustation on condenser coils, 560-562 India Docks, London and, 274 simple method of making ice in, 25 West, Docks, lifts at, 378 India-rubber packings for ammonia com- pressors, 553, 554 works, use of refrigerating machinery in, 472 Indicator diagrams, 63-66, 71, 237, 238, 566-569. See also Diagrams Industrial applications, 439-483 Inflation of balloons, use of refrigeration for purification of gas for, 472 Inglis. See Hargreaves and Inglis Injections of sealing aud lubricating oil into compressor cylinder, 53 Inlet valves, 256-260 Inspection of cold storage space on board ship, 417 Instructions to surveyors re carbonic acid machines, Board of Trade, 397 Insulating structures, transmission of heat through various, 340 Insulation, 329-371 - door, 357-361 of marine installations, 409, 411, 412 - methods of, used in U.S., 365 tank, 360-364 - window, 360 Interlaced type of condenser, 160 Internal arrangement of cold stores, 285 Interpretation of compressor diagrams, 566-569 Introduction, 1-7 Inventions for refrigerating and ice- making, various, 20 Iron, ammonia no chemical action on, 276, 277 ceilings, cellars with, 306 JACOBUS, Professor, latent heat of air, 599 Jamaica, transport of bananas from, 3 Jamieson, Professor Andrew, experi- ments by, on conductivity of sub- stances, 332, 333, 334 Jib, crane, long, for raising carcasses from barges, 378 Johnson and Whitelaw's absorption ma- chine, 209 Joints, breaking of, in ammonia machines, 551, 552 pipe, and unions, 260-268 Joint socket bend, soldered, 265 Jones, Walter, experiments regarding non-conducting properties of various substances, 341 Joule on production of very low tempera- tures, 594 Joule's mechanical equivalent of heat, 11 Juice, precautions to prevent loss of, from frozen mutton, 286 INDEX. 619 KELVIN, on production of very low temperatures, 594 Kieselguhr, result of tests as to conduc- tivities of, 333, 334, 335 use of, as an iusulating material, 329, 330 Kilbourn ammonia compressor, inclosed type, 87-89 cream cooler, 425 improved type of ammonia compres- sion machine in dairy, 425 marine ice-making or congealing tank, 418, 419 type of ammonia compression machine, 407-409 M. J. K., inventor of improvements in refrigerating machinery, 88 pipe joints, 262-264 stop-cock, 253 Kingdom, United, cold stores in, 7 Kingsford, improvements in vacuum machines, 26 Kirk, Alexander, cold-air machine, 215 Dr A. C., application of ether machine to extraction of paraffin from shale oil, 439 Klein oil separator or collector, 509 - water-cooling tower, 170 "Knight's Dictionary," description of Van der Weyde's machine, 44 Koch method of using refrigeration for constructional work, 477 Kroeschell Bros. Ice-Making Co., car- bonic acid compressor, 144-149 horizontal belt-driven carbonic acid compression machine, 147-149 rope-driven carbonic acid com- pressor, 140 vertical belt-driven carbonic acid compression machine, 147-149 LAGER beer fermenting rooms and store cellars, cooling of, 450 La Hire's epicycloidal device, 224 Lampblack, use of, for insulating pur- poses, 330 Land installations, Linde machine especially designed for, 80 Lange's improved pump for vacuum machine, 29 Latent heat, 10, 11 heat, discovery of, 10 of ammonia, 48 Laundries, use of refrigeration ice, 472 Laurenson, method of making ice, 496 Lavoisier ice calorimeter, tests of con- ductivity with, 336 Law, general, governing production of cold by frigorific mixtures, 23 Laws of gases, 12-14 Lawton, Mr A. W., process for preserving fruit, 389, 390 Leakage at joints, cocks, valves, &c., in direct expansion system, 276 of gas past piston rod, methods of preventing, 80, 83, 84, 94, 102, 103 past piston rod, stuffing box, and gland, Linde method of preventing, 72,73 See also Piston rod Leaks in ammonia apparatus, 559 in carbonic acid machines, 560 Lebrun, Mr B. , cooling pipe with gills or flanges, 269 inclosed type of compressor, 116 Lemons, cold storage of, 388, 394 Leslie, improvements in vacuum ma- chines, 26 Lifts. See Elevators or Hoists Lightfoot cold-air machine, 230-233 - insulation recommended by, 329 T. B., ammonia compressor, 91 cold-air machine, 230-234 use of, for chocolate cooling, 440 combined refrigerating and ice-making tank, 507 condenser, 155 experiments on heat conductivity of slag wool and charcoal, 342, 343 observations by, on frigorific mix- tures, 23 on cold-air machines, 212-214 on cost of working, 580, 581 particulars regarding ether ma- chine, 42, 43 results of tests with Linde com- pression machine, 80 Lighting cold stores, 576-578 Ligny-les-Aire, use of refrigeration for sinking shafts at, 476, 477 Lime, cold storage of, 388 Limit to ratio between diameter and stroke in ammonia compressors, 55 Linde, Carl, ammonia compressors, 79-83 method of agitating water during freezing, 492 Company, water-cooling tower, 172, 173 marine type ammonia compression machine, 402, 403 - production of liquid air by, 593 Lineal feet of 1-in. piping required per cubic foot of cold storage space, 282 Liquefaction of a solid, abstraction of heat by, 20 620 INDEX. Liquefaction of gases. See Production of very low temperatures process, the, 20-24 use of, by the ancients for refriger- ating purposes, 21 Liquefactor. See Condenser Liquefied agent, arrangement for remov- ing, from condenser, 159, 160 Liquefier. See Condenser Liquid air, cooling van by means of, 371 See Production of very low tem- peratures Liquor ammonia, strength of, 49 Live cattle, cooling holds of vessels for, 473 Lobrist, John, refrigerator car designed by, 370, 371 London and India Docks Co., refriger- ating installation at, 274 and Tilbury Lighterage Co. , refriger- ated barges, 421 Long-distance thermometers, 573, 574 Loose tools required in an ice factory, 529 Lorenz, Hans, interpretation of com- pressor diagrams, 566-569 Lowe, carbonic acid machine, 46 Low-pressure refrigerating agents. See Ether, Methyl chloride, Sulphurous acid Low, Professor D. A., construction of chart applicable to any value of n, 14-16 Low temperatures, production of, 588- 601 Lubrication of refrigerating machinery, 558, 559 qualities of ammonia, 552 "Lucania," refrigeration of cargo holds of, 409-411 of provision stores of, 411-413 Lugo and M'Pherson, cold-air machine, 224 See also Tuttle and Lugo Lussac's law of expansion of gases, 12, 13 Lyon's improved absorption machine, 200-203 MACDONALD, Mr C. A., ammonia compressor designed by, 106-108 Mach, Dr Ernest, on heat, 9 Machines, absorption, 20 ammonia compression, 51-116 carbonic acid compression, 45-49 capacity of, required for refrigeration of cold storage chamber, 286-289 cold-air, 20, 211-245, 415-417 ether compression, 37-44, 117-120 liquefaction process, 21, 22 Machines, methyl chloride compression, 120 sulphurous acid compression, 120- 129 Mackay and Christiansen, improvements in absorption machines, 175, 184, 185 Frederick Noel, arrangement for cool- ing cold storage rooms or chambers, 292 improvements in absorption machines, 184, 185 M'Pherson. See Lugo M'Rae, Mr J., rotary chocolate cooler, 443, 444 Main function of refrigerating and ice- making apparatus, 19 - items of expense in working, 579 Management and testing of refrigerating machinery, 530, 539-578 cold-air machines, proper, 562 Manufacture of chloride of calcium and salt solutions, 532-534 Manufacturing industrial and construc- tional applications, 439-483 Maquet gilled piping, 269 Marcet, Alex., rate of passage of heat through various materials, 329 Marchant cold-air machine, 215 Marine refrigeration, 396-421 Mariotte's law, 18 Martindale, Colonel B. H., on refriger- ating chambers at St Katherine's Docks, 272 Marvin hygrometer, 572 Mash tuns refrigerated, 445, 446 " Mataura," cargo of frozen meat in, 2 Matthews, F. F., amount of refrigeration required, 381-383 can ice, time required for freezing, 491, 492 modern absorption machine, 205- 209 plate or wall system, 495 Maurs' experiments on transmission of heat, 344, 345 Maxwell, absolute zero, 12 - definition of heat, 9, 10 Means for improving air circulation, 316- 319 increasing cooling surface of pipes, 268, 269, 292 preventing leakage at compressor piston rod, 80, 83, 84, 94, 102, 103 Meat-carrying chamber on board "Cam- pania" and "Lucania," 409-411 Meat, cold storage of, 363 frozen, history of trade in, 2 cooling plant, abattoir, Riga, 303 INDEX. 621 Meat, trade in frozen, 2 Meats and fish, freezing and storing of, 383-385 Mechanical equivalent of heat, 11, 18 or forced air circulation, 319-328 refrigeration, theory and practice of, 8-20 work demanded of a machine for, 13, 14 Mediums, refrigerating. See Agents Melbourne, first cargo of apples from, 6 Mercury well for horizontal pipe, 563 for vertical pipe, 563, 564 Method for preventing leakage of gas past compressor piston-rod, 80, 83, 84, 94, 102, 103 of testing capacity of refrigerating machine, 562-566 Methods of ice-making, various, 485-508 of piping that hinder circulation, 313- 316 Methyl chloride, advantages of, as a re- frigerating agent, 120 composition of, 120 compression machines, 120 disadvantages of, as a refrigerating agent, 120 properties of, 120 Methylic ether compression machine, 40- 42 compression machine, expansion valve for, 42 distilling apparatus, 40 Meyer steam engine for driving ammonia compressor, 114 Mica, use of, as an insulating material, 329, 367 Mild-cured bacon, use of refrigerating machinery for production of, 306 Milk, refrigeration of, 386, 422-438 shipped from Gothenburg to London, 6 - trade in frozen, 6 Mirrlees, Watson, & Yaryan Co. , distilling apparatus, 514-517 Miscellaneous arrangements for making clear or crystal ice by agitation, 499- 507 Mixer for making brine, 532, 533 Mixtures, freezing, principal, 24 frigorific, observations on, 23 Modern physicists on heat, 9 types of Boyle ammonia compressors, 97 Mois Scientifique et Industriel. See Maurs Moissau, experiments by, in liquefaction of gases, 592 Moisture in air, determination of, 470- 473 Moisture properties of absorbing gases, 313 Molesworth, heat-conducting power of various substances, 342 Mollet, Fontaine, et Cie, carbonic acid compressor, 151 Morgues, refrigeration in, 391 Mort, improvements in absorption ma- chines, 175, 181 temperature exchanger, 181 See also Nicolli and Mort Morton, Professor Henry, on power obtainable by expansion of liquid air, 599-601 Mortuaries. See Morgues Mouge, experiments by, in liquefaction of gases, 588 Mould, germs of, in atmospheric air, 313 Moulds, cold slabs or tables for, 193, 194 or cans, ice, 27 Multiple effect distilling apparatus, 510- 517 Mutton, frozen, hanging before cooking, 286 hoist, electrically-driven, 376 NATRNE vacuum machine, 26 Nalder Brothers & Thompson, Ltd., telethermometer, 575, 576 Naphtha, use of, as a refrigerating agent, 44 Natteur, experiments in the liquefaction of gases, 588 Natural system of ice-making, imitation of, 518 Neff, Mr Peter, on ratio of diameter to stroke in ammonia compressors, 56 Nelson's cold storage wharf, external carcass hoists at, 376-378 Nessler's reagent, 559 Neubecker ammonia compressor, 85 "Neuere Kuehlmaschinen," interpreta- tion of compressor diagrams, 566-569 New South Wales, imports of butter from, 6 imports of frozen meat from, 2 Zealand, imports of frozen beef from, 2 Shipping Co. , refrigerating instal- lation, 407 use of pumice stone as an insulat- ing material in, 329 Niagara Hall, artificial ice skating rink at, 473 Nicolli and Mort's improvements in ab- sorption machines, 210 Nishigawa improvements in absorption machines, 193 622 INDEX. Non-conducting materials, experiments on transmission of heat through, 344, 345 Non-conductive values of different ma- terials, results of tests as to, 337, 338 Non-heat-conducting properties of various substances, 337, 340 "Nonpareil," first cargo of West Indian fruit in, 3 Northmore, experiments by, in the lique- faction of gases, 588 Number of cubic feet covered by 1 ft. of 1-in. iron pipe, 282 of cubic feet covered by 1 ton re- frigerating capacity, 283 of firms directly interested in re- frigeration, 7 of vessels fitted with refrigerating machinery, 7 /^vBJECTIONABLE features of can \_/ system of ice-making, 488-490 Objections to the cold-air machine, 242, 243 double pipe condensers, 165 to the use of ether as a refrigerating agent, 43, 44 Observations on frigorific mixtures, 23 " Oceana," first cargo of apples in, 3 Oil for lubricating ammonia machines, 542 injection of sealing and lubricating into compressor cylinder, 53, 56-66 presence of, in ammonia system, 542 separators or collectors, 76, 509, 510, 544-549 Olszewski, experiments by, in liquefaction of gases, 591 Onions, cold storage of, 390, 391, 394 Onnes, experiments by, in liquefaction of gases, 592 Opaque ice, reasons for, 484, 485 Open-air condensers, tiee Atmospheric condensers Opening up ammonia machines, necessary precautions, 52 carbonic acid machines, necessary precautions, 556 Open trough system of cooling, 302, 303 water cooler, 168 Operation of absorption machine, 178, 179, 205-209 of Frick safety compression head, 68-70 Operations, cycle of, in ammonia com- pression machines, 52 Oranges, cold storage of, 388, 394 Ordinary form of atmospheric condenser, 158 of cream cooler, 430 Ordway, Professor John M. , experiments by, on non-conducting coverings, 304 experiments regarding non-heat- conducting properties of various substances, 340 " Orient," cargo of frozen meat in, 2 Origin of artificial refrigeration, 1 Orosius on production of cold by Estho- nian tribe, 21 Oscillating ice-making tank or box, 504 Oxydising of tea, regulation of, by re- frigeration, 464 PACIFIC Coast, salmon-freezing works on, 384 Packing carcasses in cold rooms or chambers, 271, 286 house, cubic feet of space per running foot of piping, 281 - ice, 535-537 Packings, compressor piston-rod, 552- 554 in ammonia compressor stuffing boxes, to drive home, 554 Pamely, Caleb, on Gobert method of congelation for constructional work, 477-483 Paper or cloth, hard pressed asbestos, value of, as an insulating material, 335 use of, for insulating purposes, 331 " Para," accident on board, 390 Paraffin oil works, refrigeration in, 459- 461 solid, extraction of, from shale oil by refrigeration, 459-461 Paris Exhibition, carbonic acid com- pressor at brewery section, 151 Parsnips, cold storage of, 391, 395 Partially submerged pump or piston agitator, 358, 359 Particulars regarding ether machine, 42-44 Partitions, divisional, for cold stores, 353, 354 Parts, main, required in all compression machines, 36, 37 required in ammonia compression machines, 51 Pasteurisation of milk in dairies, 431 Pastry, cold slabs or tables for the manu- facture of, 193, 194 Patent system of preventing leakage at ammonia stuffing boxes, 554 INDEX. 623 Peaches, cold storage of, 389, 395 trade in, 6 Pears, cold storage of, 388, 395 trade in, 6 Peninsular and Oriental Co. 's cold storage chamber, 418 Periodical publications dealing wholly or partly with refrigeration, 604 Perkins', Jacob, lirst compression ma- chine, 34, 35 Photographic accessories, use of refrigera- tion in manufacture of, 471 Physical constants of liquefied gases, 598 Physicists, modern, on heat, 9 Picteau fluid, 34 Pictet ammonia compressors, 91, 92 experiments by, in the liquefaction of gases, 588, 591 Raoul, experiments by, on radiation at low temperatures, 331, 332 heat units transmitted per square foot per hour, 330, 331 sulphur dioxide, or sulphurous acid machine, 44, 45 Pictet' s improvements in absorption machines, 210 Pictet. See also Tellier and Pictet Pieper, Mr, on amount of water used by Windhausen machine, 504 Pipe joints and unions, 260-269 Pipe-loft, or coil-room, system of air circulation, 318, 319 means for increasing cooling surface of, 268, 269 See also Cooling pipes Piping for cold stores, 280-284 - methods of, that hinder air circula- tion, 313-316 - breweries, 456, 457 Piston or pump agitators for making clear or crystal ice, 504-507 rod, means for preventing leakage at, 80, 83, 84, 94, 102, 103 packings, compressor, 552-554 Pitch, use of, for insulating purposes, 330 Plant growth, regulation of, by refrigera- tion, 472 Plate, heat-units transmitted through, square foot per hour, 331 or wall system of ice-making, 485, 493-496 system of making clear or crystal ice, 485-508 Poetsch process for sinking shafts by refrigeration, 475-477 Points to be looked for in a water-cool- ing tower, 170 Pontifex expansion or regulating valve, 249 Pontifex gas-tight joint, 260, 261 E. L., improvements in absorption machines, 175, 186-198 Pontifex-Wood absorption machine, cost of making ice with, 580 use of, in artificial butter works, 461-464 absorption machine, use of, in brewery, 451-455 working of, 499, 500 brine refrigerator, 445 can ice-making tank or box, 487, 488 ice-making tank or box on wall or plate system, 493, 494 improvements in absorption machines, 175, 186-193 pyramid ice-making box, 487 stationary cell system of ice-making, 497-499 Portable distilling apparatus, 516, 517 Postle cold-air machine, 215, 216 Power obtainable by expansion of 1 Ib. of liquid air, 599-601 Practice, limit in, between ratio of diameter and stroke in ammonia compressors, 55 theory and, of mechanical refrigera- tion, 8-20 Precautions when opening up compres- sion machines, necessary, 52, 555 Preservation of dead bodies by refrigera- tion, 391 of furs and various fabrics by re- frigeration, 472-473 of meat by refrigeration, 270-272 Pressure, absolute, 11, 12 and boiling point of liquids available for use in refrigerating machines, 48, 117, 120 back, loss of efficiency in ammonia compressors from, 56 Principal freezing mixtures, table of, 24 Principle of the absorption machine, 174, 205-209 Principles involved in process of refrigera- tion, simplicity of, 19 of operation of ammonia compressor, 51, 52 Process, absorption, the, 201 - compression, the, 18, 20, 34-151 liquefaction, the, 20, 21-24 vacuum, 20, 25-55 Production of cold by frigorific mixtures, general law of, 23 of very low temperatures, 588-601 Progress, history of trade in fresh pro- visions, 1-7 Propeller for brine agitation, 490, 491 624 INDEX. Proper management of cold-air machines, 562 methods of storing, and temperatures for cold storage, 381-391 Properties of ammonia, 48 carbonic acid, 129 - ether, 117 methyl chloride, 120 sulphurous acid, 120 " Protos," cargo of frozen meat in, 2 Provisional specification of Dr William Hampson, 595 Provision stores or chambers on board S. S. " Campania " and ' ' Lucania, " 411-413 - trade, fresh, 1, 2 Psychrometers. 571 Publications, periodicals, dealing wholly or partly with refrigeration, 602-604 Public buildings, cooling atmosphere of, in warm climates, 472 morgues or mortuaries, 391 Pulsometer Engineering Co., Ltd., am- monia compressors, 85-87 cell ice -making tank or box, 499 cold storage chamber, 289, 290 cost of working, 582 hand-power ice machine, 33 ice delivery machines, 527 ice tank or box room of ice factory, 519, 520 ice-making box, 495, 496 refrigerated barges, 421 refrigerated railway van, 365 Pumice stone, use of, as an insulating material, 329 Pump agitator for making clear or crystal ice, 504-507 for clearing absorber, 188 for vacuum machine, improved, 29 Puplett agitators for ice-can box, 488 ammonia compression machine in small store, 303, 304, 308 and Rigg, arrangement for lifting ice cans, 523-525 patent separator, 545, 546 regulating valve, 248, 249 marine type of ammonia compressor, 403 Samuel, improvements in ammonia compressors, 92, 93 Puplett's water-saving and cooling ap- paratus, 168, 169 Purification of gas for inflation of balloons, use of refrigeration for, 472 Purity of carbonic acid, to test, 129 Pyramid ice-making box, 487 /^VITALITIES of ammonia, lubri- \J eating, 552 ^ principal, to be sought for in compressor, 53, 56 rendering carbonic acid particularly suitable for use on ship-board, 397 Quality of oil to be used for sealing and lubricating purposes in ammonia compressors, 57 Queensland, imports of frozen beef from, 3 Quiri & Co., atmospheric condensers, 161 sulphur dioxide compression ma- chines, 123, 124 RABBITS, trade in frozen, 3 Radiation of heat through walls of cold storage chambers, &c., 287 289 Railway vans, refrigerated, 365-371 Ransome and Rapier absorption machine, 198-200 Raoul Pictet Co., sulphurous acid ma- chine, 129 sulphur dioxide or sulphurous acid machine, 44, 45 Rapid liquefaction of a solid, abstraction of heat by, 20 Ratio between diameter and stroke of ammonia compressor, 54, 56 Rau's atmospheric condenser, 161 Reaumur's thermometrical scale, zero on, 12 Reciprocating agitators for making clear or crystal ice, 487-499 Red currants, cold storage of, 389 Reece, Rees,. improvements in absorption machines, 175, 179-181 Refineries, sugar, refrigeration in, 464, 465 Refrigerated railway vans, 365-371 Refrigerating apparatus, amount of water required by, 570 capacities, table of, 284 capacity in B.T.U. required per cubic foot of storage, 283 coils, defrosting, 560, 561 machine a heat pump, 19 greatest theoretical efficiency of, 17 machinery, classification of, 20 lubrication of, 558, 559 - testing of, 564 -568 Refrigeration, amount of, required in cold stores, 286-289 and cold storage, 270-395 - bibliography of, 602-604 INDEX. 625 Refrigeration by means of cold-air machines, 272, 274 compression and absorption ma- chines, 274 chemical process of, 20, 21-24 in butter manufactories and dairies, 422-438 marine, 396-421 mechanical, theory and practice of, 8-20 working of a machine for, 15, 16 - number of firms directly interested in, 7 use of, in various industries, 439-483 Refrigerator. See Evaporator Regealed ice machine, 507, 508 Regenerative method of producing very low temperatures, 592-599 Registering thermometers, 574, 575 Regularity of temperature of fruit cargo, necessities for, 419, 420 Regulating the temperature of ferment- ing of tea by refrigeration, 464 - valves. See Expansion valves Regulation of plant-growth by refrigera- tion, 472 Relative humidity for a given tempera- ture in egg rooms, correct, 387, 388 of air per cent. , 572 Remington Machine Co., single-acting inclosed pattern ammonia com- pressor, 99, 100 Results of experiments on the conduc- tivities of various substances, 336 regarding heat-conducting pro- perties of various substances, 339, 340 - regarding non - heat - conducting properties of various substances, 340, 341 of tests to determine the non-con- ductive values of different materials, Donaldson, 337, 338 the non-conductive values of various materials, Wallace, 338 of tests on the heat-conductivity of different substances, 339, 340 Return socket bend, 265, 266 Revolving door for cold storage rooms, 310-312 Rhigoline, use of, as a refrigerating agent, 4o Rice, Mr A. L. , on production of very low temperatures, 593, 594, 599 Richardson, Dr B. W., on effect of ammonia on fresh meat, 276, 277 Rich, H. S., & Co., work on eggs in cold storage, 388 Riga abattoir meat-cooling plant, 303 40 Rigg, Jonathan Lucas, improvements in ammonia compressors, 92, 93 See Puplett and Rigg Rilleux, triple-effect distilling apparatus, 510 Rink, artificial surfaces of ice at, 473 River Plate, imports of frozen mutton and beef from, 3, 5 Rocking or oscillating ice-making tank or box, 504 Romans, cooling of wine by, with salt- petre, 21 Roscoe, Sir Henry E., on carbonic acid, 47 Rossi. See De Motay and Rossi Rotary agitators for making clear or crystal ice, 487 Rotating discs, arrangement for cooling air with, 297 door for cold storage rooms, 310-312 exhaust pump or cylinder, 30 Rough estimate of refrigeration in breweries, 457 " Ruapehu," refrigerating installation on board of, 407 Ruddick, J. A., on dairy refrigeration, 431-436 Rugs, preservation of, by use of refrigera- tion, 472 Rumford, Count, definition of heat by, 8 Ryan, T. J., refrigerator car, 371 SABROE & CO., LTD., D., carbonic acid machine, 151 Thomas Ths., sulphurous acid machine, 129 Sacking saturated with cold brine, cool- ing air with, 297 Safety devices for compressors, 71-76 heads for compressor cylinders, 66-74, 105 valves for carbonic acid machine, 135, 144, 146, 149 Salmon-freezing works on Pacific Coast, 384 Salsify, cold storage of, 391 Sand bach, combined cream cooler and heater, 430 Santorio, cooling wine by mixture of snow and salt, 21 Saving of power and cooling water in condensers, 164, 165 Schmidt, M. E., refrigerator car, 371 on Poetsch process of sinking shafts by refrigeration, 477 Schmitz, Mr Constanz, method of testing capacity of refrigerating machine, 566, 567 626 INDEX. Schou, H. H., patent evaporator, 155 Scientific American, article on effect of ammonia on fresh meat, 276 Screen or apron in front of side-wall piping, 316, 317 Screw agitator. See Agitator Screwed and soldered joints, 261-266 Seeley, improvements in absorption machines, 193, 209 Self-contained marine type of ammonia compression machine, 407, 408 Selfe, Norman, ammonia compressor, 108 Self -registering thermometer. See Ther- mograph Selling ice, 536, 537 Semi-cylindrical door for cold storage rooms, 310-312 Semi-steel, use of, in compressor cylinder, 145 Senssenbrenner, C., ammonia absorp- tion machine, 203 Sensible heat, 10 Separators or collectors, oil, 76, 509, 510, 544-549 Shafts, use of refrigeration for sinking, 472, 474-483 ventilating, for cold stores, 312 Shale oil, extraction of solid paraffin from, by refrigeration, 460, 461 Shallow stationary cell system of mak- ing clear ice, 485 Shipley, Mr Thomas, improvements in St Clair compressor, 116 Ships' holds, method of sterilising cold air for use in, 420, 421 Siberian rivers, use of refrigeration for prospecting in, 477 Siebe, Gorman, & Co. , ether compression machine, 38-40, 43 Siebel, Professor, amount of condensing surface required in atmospheric condensers, 156 on cold storage of fruits, 388 on dimensions of submerged con- densers, 155 radiation through walls, c. , 287 Siemens' ice-making apparatus, 22 experiments by, in liquefaction of gases, 588, 592 liquefaction process, cost of making ice by, 584 Silicate cotton. See Slag wool Silks, preservation of, by means of re- frigeration, 472 Simple method of procuring ice, used in France, 25 of producing ice in hot climates, 25 "Simplex" absorption machine, 198-200 Simplicity of principles involved in pro- cess of refrigeration, 19 Sinclair improvements in absorption machines, 193, 194 Single-acting compressors, advantages of, 57 disadvantages of, 51 losses due to clearances in, 54, 55 compound marine type ammonia compressor, 407 effect, Yaiyan distilling apparatus. 510-517 Sinking of colliery shafts, application of refrigeration to, 472, 474-483 Sizes and capacities of various ice-making plants, 532 Skelp, condenser pipes made of, 161 Skinkle, Eugene T., table of dimensions of atmospheric condensers, 157 of submerged condensers, 157 Slabs or table, cold, for manufacture of chocolate, &c., 193, 194 Slag wool, consistency for packing insu- lating spaces with, 330 use of, as an insulating material, 329 Small brewery, plan of refrigerating plant for, 458 cold storage chamber, with Haslam cold-air machine, 306-308 with Puplett ammonia com- pression machine, 308 with Triumph ammonia compression machine, 308, 309 Snow, removal of, from refrigerating surfaces, 292 marine cold storage chamber, 417 Societe Genevoise de Construction, sul- phurous acid machine, 129 Socket bent joint, 265 - return, 265-267 Soda-water works, vise of refrigeration in, 472 Sodium, chloride of. See Salt Soft fruits, trade in, 6 Solid, abstraction of heat bv liquefaction of, 20 - paraffin, extraction of, from shale oil, by refrigeration, 459-461 steel forging for compressor cylinders, 144 Solidification as a test for purity of car- bonic acid, 129, 130 Solway, regenerative method of produc- ing low temperatures, 593 Soudan Campaign, use of ether machine during, 120 INDEX. 627 South Africa, use of ether machine in, 120 Southampton Docks, cold stores or chambers at, 285, 286 Cold Storage Co., elevators, 375, 376 Southby. See Blyth and Southby South Wales, New, imports of butter from, 6 imports of frozen beef from, 2 Spattering of cooling water in atmos- pheric condensers, to prevent, 159 Specific gravity of ice, 484 - heat, 10 and composition of victuals, 498 - definition of, 10 - of ice, 484 of water, 10 Spiral agitator for can ice-making box, 487 Spring safety compressor heads, 65-70 Stallman's ammonia compressor, 105, 106 Standard Butter Co., railway van cooled by liquid air, 371 Stanley, H. F. , improvements in absorp- tion machines, 175, 181-184 refrigerator car, designed by, 368-370 Starr, transmission of heat through various insulating structures, 344 Starting ammonia machine, 541 Stationary cell system of ice making, 496-499 St Clair compound ammonia compres- sor, 116 system of circulating air in cold chambers, 318, 319 St Katherine Docks, refrigerating chambers at, 272-274 Steel flange unions, 264 Steinle thermometer, used on chocolate cooler, 443 Sterne, L., & Co., Ltd., ammonia com- pressors, 56-66 Stevenson's cold-air machine, 225 Stewart & Co., Ltd., D., carbonic acid compression machine, 151 Stewart Balfour on rise of temperature of air under compression, 10 Still for absorption machine, 174. See also Generator Stocker water-cooling tower, 170 Stockholm, construction of tunnel by refrigeration at, 474 Stoddard, paper on waterproofing bricks, 345-350 Stop-cocks and valves, 252-256 Storage chambers, amount of refrigerating pipes required for, 280, 281 of fruit cargo, proper, 418, 419 Storage of various articles, proper tem- perature for, 392-395 Stores, cold, number of, in United King- dom, 7 walls for, 350-354 Storing ice, 535-537 meats and fish, 383-385 Strainer, brine, 491 Straiton, Mr John, door for cold storage rooms, 360 " Strathleven," first cargo of frozen meat brought over in, 2 Strawberries, cold storage of, 389 Stroke, ratio between, and diameter in ammonia compressors, 54-56 Stuffing boxes for ammonia compressors, 552-554 box glands, sealing of, 56, 57 Sturgeon's cold-air machine, 225 Submerged condensers, 134, 152-157 Successive cycle system of producing very low temperatures, 589, 590 Suction and discharge valves, 256-260 Sugar factories and refineries, use of re- frigeration in, 464, 465 machinery, treatise on, 465 Sulphur dioxide. See Sulphurous acid Sulphuric acid refrigerating machines, 27, 33 ether compression machine, 39, 40 Sulphurous acid, advantages of, as a re- frigerating agent, 44, 45 - machine, 44, 45, 120-129 objections to use of, as a refri- gerating agent, 45 properties of, 44, 45 Sulzer engine, compressor pumps driven by, 81, 124 Superheating of ammonia gas in com- pressor cylinder, means for pre- venting, 91 Suppes and Dortch, expansion valve, 251, 252 Supplementary condensers or forecoolers, 164, 165 Surfaces, brick, waterproof coatings for, 345-350 of cooling pipes, to increase, 268, 269, 292 Swiss Co-operative Society refrigerating plant, 428, 429 Sylvester process for waterproofing brick, 350 System, absorption, the, 20, 174-210 cold air, the, 211-245 - compression, the, 20, 34-151, 557, 558 liquefaction, the, 20, 21-24 Systems of operating ammonia compres- sion machines, two, 52 628 INDEX. TABLE giving size and capacities of various ice-making plants, 523 the extreme limits of cubic feet of space per running foot of 2-in. piping, 281 the relative heat-conductivity of various boiler-covering materials, 340 of amount of heat-units transmitted, per square foot per hour, through various substances, 330 of approximate cost of ice-making, 587 operating ice factories, 586 - of calculated relative amounts of vapour condensed and deposited in the various stages of cooling, 230, 231 of conductivities of asbestos and Kieselguhr composition, 334 of correct relative humidity for a given temperature in egg rooms, 388 of cubic feet of ammonia gas per minute to produce 1 ton of refri- geration per day, 278 of space per running foot of 2-in. pipe direct expansion, 281 of dimensions of atmospheric con- densers, 164 of submerged condensers, 157 of extreme limits of cubic feet of space per running foot of 2-in. piping, 281 of freezing times for different tem- peratures, and thicknesses of can ice, 530 of heat-conducting power of various substances, slate being 1,000, 342 of ice plant efficiencies, 531 of ice required for refrigeration in dairies, 435 of lineal feet of 1-in. piping re- quired per cubic foot of cold storage space, 282 of non- heat-conducting properties of various substances, 340 of number of cubic feet covered by 1 ft. of 1-in. iron pipe, 282 of number of cubic feet covered by 1-ton refrigerating capacity for twenty-four hours, 283 of physical constants of liquefied gases, 598 of principal freezing mixtures, 24 of rate of passage of heat through various materials, 339 of ratio of piping in brewery cellars, 456, 457 Table of refrigerating capacities, 284 capacity required per cubic foot of storage room, 283 refrigeration required to cool meats, 382 of relative humidity for given tem- perature in egg rooms, 388 - per cent. , 572 of results of different experiments on the heat conductivities of various substances, 336 of experiments regarding non-heat- conducting properties of various substances, 340, 343 of test experiments made with cold-air machines, 244 of tests to determine the non- conductive values of different ma- terials, 337, 338 of tests to determine the non- conductive values of various ma- terials, 338 of tests on the heat conductivity of different substances, 339 of tests by Professor Jamieson as to relative and absolute thermal conductivities of substances, 333 of specific heat and composition of victuals, 383 of temperatures adapted for the cold storage of various articles, 392- 395 of tests of waterproofing bricks, 345- 350 of time required for water to freeze in ice cans, 491, 531 of weights of aqueous vapour held in suspension in pure dry air, 573 of yearly imports of frozen and chilled beef, 5 of yearly imports of frozen mutton and lamb, 3, 4 showing transmission of heat through various insulating structiires, 344 Tables or slabs, cold, for manufacture of chocolate, &c., 193, 194 Tabor, C. J., on preservation of fish, 384, 385 Taiicredus, Latinus, freezing water by mixture of snow and saltpetre, 21 Tangye pattern frame ammonia compres- sor, 108, 109 Tank insulation, 361-364 Tapestries, preservation of, by means of refrigeration, 472 Tayler. See Wallis-Tayler Taylor's patent fittings for doors of cold stores, 360 INDEX. 629 Tea regulating, fermenting of, by refriger- ation, 464 Telethermometer, or electrical ther- mometer, 575, 576 Tellier and Pictet machines, cost of making ice with, 583 Charles, methylic ether compression machine, 40-42 Tell-tales. See Temperature tell-tales Temperature absolute, 12 and heat, distinct meanings of, 10 - best, to maintain a fruit cargo, 419 exchanger and economise!', 181, 197 of condensed gas most economical, 168 of oxydising or fermentation of tea by refrigeration, 464 tell-tales and long distance ther- mometers, 573, 574 Temperatures for the cold storage of various articles, proper, 392-395 production of very low, 588, 601 Tender fruits, cold storage of, 388 Testing of refrigerating machinery, 563- 576 work of carbonic acid machine, 481 Tests of purity of carbonic acids, 129- 131 of waterproofing brick, 345-350 Thames, refrigerated barges on, 421 Theoretical efficiency of a refrigerating machine, greatest, 17 Theory and practice of mechanical re- frigeration, 8-20 Thermo-dvnamics, first laws of, 8-19 Thermographs, 419, 574, 575 Thermometers, long distance, 573, 574 Thermometrical scale, Fahr., zero on, 12 Thomas, F. S., arrangement for increas- ing the surface of cooling pipes, 292 Thompson, Benjamin. /See Rumford M. R., on filling ice houses, 335 Thorne, method of making ice, 495 Time required for water to freeze in ice cans, 491, 531 Tomkins, E. H., improvements in absorp- tion machines, 175, 185, 186 Tools, loose, required in ice factory, 529 Toselli's ice-making machine, 22 Tower, air-cooling, 295-297 - water-cooling, 168-173 Track system for ice factories, 527 Trade in Australian apples, 6 - in fresh provisions, 1-7 in frozen cream, 6 in frozen meat, 2 Trade in grapes, 6 in peaches, 6 in pears, 6 Trans-Mississippi Exposition, refrigerat- ing machine at, 110, 111 Trays, drip. /Ste Drip trays Triple-effect distilling apparatus, 510- 512 Tripler's apparatus for the produc- tion of very low temperatures, 593- 595 Triumph Ice Machine Co., approximate cost of ice-making, 587 atmospheric condenser, 160 automatic ice dump, 525-527 complete brewery refrigerating plant, 458 dimensions of submerged condensers, 155, 156 discharge and suction valves, 259, 260 double-acting ammonia compressor, 89-91 expansion valves, 247, 252 oil separator or collector, 509, 549 plan of ice factory, 520 - plan for insulation, 365 propeller for brine agitation, 490, 491 - small cold storage room, 308, 309 stop-valve, 253, 254 water-cooling tower, 171, 172 Tropical climates, cooling of hospitals, &c., in, 472 Trotter, Mr A. P., long distance ther- mometer, 574 Trough, open, system of cooling, 303 Truman, Hanbury, & Co. , brewery, first use of ether machine at, 439 Trunk for admitting cold air in marine installations, 416, 417 Trunks or ducts, Puplett's arrangement of, 303, 304 Tunnelling, application of refrigeration to, 474 Tuttle and Lugo, cold-air machine, 224 Tuxen and Hammerich Engineering Works, Ltd., ammonia compressor, 100-102 carbonic acid compressor, 151 Twining and Harrison, wall or plate system of ice making, 493 Professor, improved compression machine, 37, 38 Tyler and Ellis Manufacturing Co. , Ltd. , ammonia absorption machine, 198- 200 Tyndall, Professor, definition of heat by, 9 630 INDEX. UNIONS, flange, 264-269 - pipe joints and, 260-269 United Kingdom, cold stores in, 7 - imports of frozen provisions into, 1-7 States, construction of first refrigera- tor car in, 366 Illinois Central Railway, re- frigerator car on, 367-370 method of freezing fish in, 383, 384 insulation used in, 365 - pattern of Linde ammonia com- pressor made in, 81 refrigeration in, 7 selling and delivering of ice in, 536, 537 water - cooling towers in, 168- 173 Unit of measure of heat, 1 1 Unnecessary clearance spaces in ammonia compressor, 53-56 Upholstered furniture, preservation of, by refrigeration, 472 Utilisation of dissolution of a solid to abstract heat, 20, 21-24 VACUUM flasks for liquid air, 591 machine, cost of making ice by, 584 improved pump for, 29 - process, the, 20, 25-33 - system of ice making, 517, 518 of refrigeration, the, 20. See also Vacuum process Vallance, improvements in vacuum machines, 26 Valves, safety, 52, 54, 135, 144, 146, 149 compressor, unnecessary clearance spaces, 56 - discharge, 256-260 expansion, 42, 53 - inlet, 256-260 - suction, 256-260 See also Cocks, Valves, &c. Value of different substances, non-con- ductive, 337, 338 Van der Weyde refrigerating machine, 44 system of packing ice, 530 Vans, railway, refrigerated, 365-371 Vapour, method of cooling in compres- sion cylinder, 80 See also Gas Various articles, proper temperatures for cold storage of, 381-395 Various insulating structures, table show- ing transmission of heat through, 344 inventions for refrigerating and ice- making, 20 manufacturing, industrial, and con- structional applications of refrigera- tion, 438-483 - methods of ice-making, 485-508 substances, results of experiments on the heat conductivity of, 331, 336 of tests on the heat con- ductivity of, 333 used for purposes of insulation, 329-371 Vault in brewery, cooling of, 451 Vegetables, cold storage of, 390, 391 Vendin-Sens, use of refrigeration for sink- ing shafts at, 475 Ventilation of cold storage chambers, 312, 313 Ventilating shafts for cold stores, 312 Vernon, Mr C. E., electric temperature tell-tales, 573, 574 Vertical duplex marine type of carbonic acid machine, 401 - marine types of cold-air machines, 414-417 type of single-acting ammonia com- pression machine, 402 pipe, mercury well for, 563 Very low temperatures, 588-601 Vessels carrying live cattle, cooling holds of, 473 fitted with refrigerating machinery, number of, 7 Vicq-Auzin, use of refrigeration for sink- ing shafts at, 475 Victoria Dock, lifts at, 378 imports of butter from, 6 imports of frozen beef from, 3 Victuals, specific heat and composition of, 383 Villafranca, Blasius, use of saltpetre by, for the reduction of temperature, 21 Vilter Manufacturing Co., ammonia compressor, 81-83 Vogt Machine Co., Henry, improved ammonia absorption machine, 196, 197 Volatile liquid agents, 34 Voorhees, Mr Gardner F., oil separator or collector, 547 V-shaped or corrugated bottom to cool- ing tank, 291, 292 Vulcan Iron Works, amount of water required in refrigerating apparatus, 570 INDEX. 63' Vulcan horizontal double-acting ammonia compression machine, 112-114 ice factory, 520 inclosed type ammonia compressor, 114, 115 track system, 527 WAGONS, refrigerated. See Vans Walker laboratory ice-making machine, 22 Wallace, Dr Wm., results of tests by, to determine non-conductive values of various materials, 338 Wallis-Tayler and Whitehead, revolving door for cold stores, 310-312 tests conducted by, on cold-air machines, 244 Wall or plate system of making clear ice, 485, 493-496 system, plan for chilling and freez- ing by circulation of cold brine on, 292, 293 Walls for cold stores, 350-354 of cold stores, radiation of heat through, 287-289 Washed intestines of freshly killed pigs, experiments with ammonia on, 276 Washing, cooling, and drying air, ap- paratus for, 297, 298 Wastage of ice, 536 Water, amount of, required in refriger- ating apparatus, 570 common arrangement for distribu- tion in atmospheric condensers, 157, 158 consumption in carbonic acid ma- chines, 142 in sulphuric acid machine, 28, 29 in sulphuric ether machine, 39, 43 cooling apparatus, 152-173 towers, 168-173 de-aerating or distilling apparatus, 508 517 distributing arrangement, 158, 159 presence of, in ammonia system, 542 saving and cooling apparatus, 168- 173 specific heat of, 10 Waterproof coatings for brick surfaces, 345-350 Way good & Co., external carcass hoist, 376-378 - lifts, passenger or goods, 378-380 Webb's arrangement of suction valves for ammonia compressors, 408 Weddel & Co., on imports of mutton, lamb, and beef, 2-5 Wedge, adjustable shoes on crossheads of compressor, 83 doors for cold stores, 357-360 Wegelin and Hiibner carbonic acid com- pression machine, 151 Well, mercury, for horizontal pipe, 563 vertical pipe, 563, 564 sinking, application of refrigeration to, 473 Westerlin and Campbell double -pipe con- denser, 165 West, H. J., Co., Ltd., carbonic acid compression machines, 141-144 ether compression machine, 118-120 submerged condenser, 154 - See also Delia Beffa and West West India Docks, lifts at, 378 Indian fruit, first cargo of, 3 - Smithfield, lifts at, 378-380 Wet system of operating ammonia com- pression machines, 52, 53 Wetzel pan, water- cooling tower on principle of, 173 Weyde, Van der, refrigerating machine, 44 system of packing ice, 530 White bleaching of clothes by refrigera- tion, 472 Whitehead. See- Wallis-Tayler and Whitehead Whitelaw. See Johnson and Whitelaw Williamson's cold storage chamber, 293, 294 Wilson, Thos., Sons, & Co., steamers fitted with refrigerating machinery for the butter trade, 6 Windhausen apparatus for production of very low temperatures, 593 carbonic acid machine, 45, 46, 131 cold-air machine, 216-221 Franz, compound vacuum pump, 27 machine, cost of making ice with, 583, 584 installation of, at Bayswater, 27 Window insulation, 360 Windows of cold stores, radiation of heat through, 287 Wine growers and merchants, use of re- frigerating machinery by, 469-471 Witting gilled piping, 269 Wolf Co., Fred. W., atmospheric con- densers, 161 recent design of Linde compressor made by, 81 See also Pontifex and Wood Work, carbonic acid machine, to charge and, 554-556 demanded of a machine for effecting mechanical refrigeration, 15-19 632 INDEX Working, cost of, 579-587 York Manufacturing Co., compound Wort, beer, cooling of, 444-446 ammonia compressor, 97-99 Worthington water-cooling tower, 170 improved St Clair ammonia com- Wroblewski, experiments by, in lique- pressor, 116 faction of gases, 591 single-acting ammonia compressor, 97-99 Y ARYAN catchalls, modified ar- rangement of, 547, 548 r ^ERO on Centigrade thermometrical distilling apparatus, 510-517 /^ scale, 12 oil separator, 547, 548 on Fahrenheit thermometrical scale, 12 Yeast rooms, brewery, cooling air in, real, 12 446, 447 Zschocke water-cooling tower, 171 Printed by THE DARIEN PRESS, Edinburgh. CROSBY LOCKWOOD & SON'S LIST OF WORKS ON CIVIL, MECHANICAL, MARINE AND ELECTRICAL ENGINEERING. 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(Refrigeration, Ice-Making, and Cold Storage); The ENGINEERS AND CARRIAGE SUPERINTENDENTS of the principal British Railway Companies (Locomotives and iRolIing Stock ; Permanent-Way Plant, &c. 12 CROSBY LOCK WOOD & SOWS CATALOGUE. ENGINEMAN'S POCKET COMPANION, and Practical Educator for Enginemen, Boiler Attendants, and Mechanics. By MICHAEL REYNOLDS. With 45 Illustrations and numerous Diagrams. Fifth Edition. Royal i8mo, strongly bound for pocket wear 35. 6d. EXCAVATION (EARTH AND ROCK). A Practical Treatise, by CHARLES PRELINI, C.E. 365 pp., with Tables, many Diagrams and Engravings. Royal 8vo, cloth ... ... Net ids. FACTORY ACCOUNTS* Their Principles and Practice. A Handbook for Accountants and Manufacturers. By E. GARCKE and J. M. FELLS. Sixth Edition, Revised and considerably extended. 314 pages. Demy Svo, cloth Net 6s. FIRE PROTECTION IN BUILDINGS* A Practical Treatise for Engineers, Architects, Surveyors, and Property Owners. By HAROLD G. 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Fourth Edition Crown Svo cloth ... ... ... ... ... ... ... 35. 6d. FUELS: SOLID, LIQUID, AND GASEOUS. Their Analysis and Valuation. For the Use of Chemists and Engineers. By H. J. PHILLIPS, F.C.S., formerly Analytical and Consulting Chemist to the Great Eastern Railway. Fourth Edition. Crown Svo, cloth. 25. od. GAS AND OIL ENGINE MANAGEMENT. A Practical Guide for Users and Attendants, being Notes on Selection, Construction and Management. By M. Powis BALE, M.Inst.C.E., M.I.Mech.E., Author of "Woodworking Machinery," etc. Third Edition, Enlarged. Crown Svo, cloth Net 35. 6d. GAS-ENGINE, A HANDBOOK ON THE. Comprising a Practical Treatise on Internal Combustion Engines. For the Use of Engine Builders, Engineers, Mechanical Draughtsmen, Engineering Students, Users of Internal Combustion Engines, and others. By HERMAN HAEDER, Civil Engineer, Wiesbaden. Translated from the German, and edited by WILLIAM M. HUSKISSON, A.M.I.E.E. (9^ years with Messrs. Crossley Bros., of Openshaw). With the addition of numerous Useful Tables and other Matter. 330 pages, with over 500 Illustrations and Tables. Small 4to, cloth Net i8s. " There can be no question as to the utility of the work, and the translator is to be congratulated on the thoroughness with which he has discharged his task." Mechanical World. " The work is in every respect of a very high standard, and may be strongly recommended to those who wish to make a study of the technical details of the internal combustion engine." Journal of Gas Lighting. CIVIL,.MECHAN1CAL, ELECTRICAL & MARINE ENGINEERING. 13 GAS ENGINEER'S POCKET-BOOK. Comprising Tables, Notes and Memoranda relating to the Manufacture, Distribution, and Use of Coal Gas and the Construction of Gas Works. By H. O'CONNOR, A.M.Inst.C.E. Third Ed., Revised. Crown 8vo, leather Net ics. 6d. GAS-ENGINE HANDBOOK* A Manual of Useful Information for the Designer and the Engineer. By E. W. ROBERTS, M.E. With Forty Full-page Engravings. Small Fcap. 8vo, leather. Net 8s. 6d. GAS-ENGINES AND PRODUCER-GAS PLANTS* A Treatise setting forth the Principles of Gas Engines and Producer Design, the Selection and Installation of an Engine, the Care of Gas Engines and Producer-Gas Plants, with a Chapter on Volatile Hydro- carbon and Oil Engines. By R. E. MATHOT, M.E. Translated from the French. With a Preface by DUGALD CLERK, M.Inst.C.E., F.C.S. Medium 8vo, cloth, 310 pages, with about 150 Illustrations. Net I2S. MOTIVE POWER AND COST OK INSTALLATION SELECTION OF AN ENGINE INSTALLATION OF AN ENGINE FOUNDATION AND EXHAUST WATER CIRCULATION LUBRICATION CONDITIONS OF PERFECT OPERATION How TO START AN ENGINE PRECAUTIONS PERTURBATIONS IN THE OPERATION OF ENGINES PRODUCER-GAS ENGINES PRODUCER-GASPRESSURE GAS-PRODUCERS SUCTION GAS-PRODUCERSOIL AND VOLATILE HYDROCARBON ENGINES THE SELECTION OF AN ENGINE. GAS ENGINES* With Appendix describing a Recent Engine with Tube Igniter. By T. M. GOODEVE, M.A. Crown 8vo, cloth. 2S, 6d. GAS ENGINES (FARM). By H. R. 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PREPARATION OF STANDARD SOLUTIONS ANALYSIS OF COALS DESCRIPTION OF VARIOUS TYPES OF FURNACES PRODUCTS OF CARBONISATION AT VARIOUS TEMPERATURES ANALYSIS OF CRUDE GAS ANALYSIS OF LIME ANALYSIS OF AMMONIACAL LIQUOR ANALYTICAL VALUATION OF OXIDE OF IRON ESTIMATION OF NAPHTHAI.IN ANALYSIS OF FIRE-BRICKS AND FIRE-CLAY ART OF PHOTOMETRY CARBURETTED WATER GAS APPENDIX CONTAINING STATUTORY AND OFFICIAL REGULATIONS FOR TESTING GAS, VALUABLE EXCERPTS FROM VARIOUS IMPORTANT PAPERS ON GAS CHEMISTRY, USEFUL TABLES, MEMORANDA, ETC. GAS WORKS. Their Construction and Arrangement, and the Manufacture and Distribution of Coal Gas. By S. HUGHES, C.E. Ninth Edition. Revised, with Notices of Recent Improvements, by HENRY O'CONNOR, A.M.Inst.C.E. Crown Svo, cloth ... 6s. GEOMETRY. For the Architect, Engineer, and Mechanic. By E. W. TARN, M.A., Architect. Svo, cloth 95. GEOMETRY FOR TECHNICAL STUDENTS. By E. H. SPRAGUE, A.M.Inst.C.E. Crown 8vo, cloth Net is. GEOMETRY OF COMPASSES. By OLIVER BYRNE. 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SUMMARY OF CONTENTS : PRINCIPLES OF HYDRAULICS THE FLOW OF WATER- HYDRAULIC PRESSURES MATERIAL TEST LOAD PACKING FOR SLIDING SURFACES PIPE JOINTS CONTROLLING VALVES PLATFORM LIFTS WORKSHOP AND FOUNDRY CRANES WAREHOUSE AND DOCK CRANES HYDRAULIC ACCUMULATORS PRESSES FOR BALING AND OTHER PURPOSES SHEET METAL WORKING AND FORGING MACHINERY HYDRAULIC RIVETERS HAND AND POWER PUMPS STEAM PUMPS TURBINES IMPULSE TURBINES REACTION TURBINES DESIGN OF TURBINES IN DETAIL WATER WHEELS HYDRAULIC ENGINES RECENT ACHIEVEMENTS PRESSURE OF WATER ACTION OF PUMPS, ETC. INTERNAL COMBUSTION ENGINES. Their Theory, Construction, and Operation. By ROLLA C. CARPENTER, M.M.E., LL.D., and H. DlEDERlCHS, M.E., Professors of Experimental Engi- neering, Sibley College, Cornell University. 610 pages, with 373 Illus- trations. Medium 8vo, cloth A>/2is. INTRODUCTION, DEFINITIONS AND CLASSIFICATIONS, INDICATED AND BRAKE HORSF-POWER THERMODYNAMICS OF THE GAS ENGINE THEORETICAL COMPARISON OF VARIOUS TYPES OF INTERNAL COMBUSTION ENGINES THE VARIOUS EVENTS OF THE CONSTANT- VOLUME AND CONSTANT-PRESSURE CYCLE AS MODIFIED BY PRACTICAL CONDITIONS THE TEMPERATURE ENTROPY DIAGRAM APPLIED TO THE GAS ENGINE COMBUSTION GAS-NGINK FUELS, THE SOLID FUELS, GAS PRODUCERS THE GAS-ENGINE FUELS, LIQUID FUELS, CARBURETTERS AND VAPORISERS GAS-ENGINE FUELS, THE GAS FUELS, THE FUEL MIXTURE EXPLOSIBILITY, PRES- SURE AND TEMPERATURE THE HISTORY OF THE GAS ENGINE MODERN TYPES OF INTERNAL COMBUSTION ENGINES GAS ENGINE AUXILIARIES, IGNITION, MUFFLERS, AND STARTING APPARATUS REGULATION OF INTERNAL COMBUSTION ENGINES THE ESTIMATION OF POWER OF GAS ENGINES METHODS OF TESTING INTERNAL COMBUSTION ENGINES THE PERFORMANCE OF GAS ENGINES AND GAS PRODUCERS COST OF INSTALLATION AND OF OPERATION. IRON AND METAL TRADES COMPANION. 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Imperial 4to, elegantly and substantially half-bound in morocco Net 6 6s. LIST OF CONTENTS: I. HISTORICAL SKETCH OF SOME OF THE MEANS THAT HAVE BEEN ADOPTED FOR THK SUPPLY OF WATER TO ClTIES AND TOWNS II. WATER AND THE FOREIGN MATTER USUALLY ASSOCIATED WITH IT. III. RAINFALL AND EVAPORATION. IV. SPRINGS AND THE WATER-BEARING FORMATIONS OF VARIOUS DISTRICTS. V. MEASUREMENT AND ESTIMATION OF THE FLOW OF WATER. VI. ON THE SELECTION OF THE SOURCE OF SUPPLY. VII. WELLS. VIII. RESERVOIRS. IX. THE PURIFICATION OP WATER. X. PUMPS. XI. PUMPING MACHINERY. XII. CONDUITS. XIII. DISTRIBUTION OF WATEK. XIV. METERS, SERVICE PIPES, AND HOUSE FITTINGS. XV. THE LAW AND ECONOMY OF WATER WORKS. XVI. CONSTANT AND INTERMITTENT SUPPLY. XVII. DESCRIPTION OF PLATES APPENDICES, GIVING TABLES OF RATES OF SUPPLY, VELOCITIES, ETC., ETC., TOGETHER WITH SPECIFICATIONS OF SEVERAL WORKS ILLUSTRATED, AMONG WHICH WILL BE FOUND: ABERDEEN, BIDEFORD, CANTERBURY, DUNDEE, HALIFAX, LAMBETH, ROTHERHAM, DUBLIN, AND OTHERS. " The roost systematic and valuable work upon water supply hitherto produced in English, or in any other language. Mr. Humber's work is characterised almost throughout by an exhaustiveness much more distinctive of French and German than of English technical treatises." Engineer. WATER SUPPLY OF TOWNS AND THE CON- STRUCTION OF WATERWORKS. A Practical Treatise for the Use of Engineers and Students of Engineering. By W. K. BURTON, A.M.Inst.C.E., Consulting Engineer to the Tokyo Waterworks. Third Edition, Revised. Edited by ALLAN GREENWELL, F.G.S., A.M.Inst.C.E., with numerous Plates and Illustrations. Super-royal 8vo, buckram. 255. I. INTRODUCTORY. II. DIFFERENT QUALITIES OF WATER. Ill, QUANTITY OF WATER TO BE PROVIDED. IV. ON ASCERTAINING WHETHER A PROPOSED SOURCE OK SUPPLY is SUFFICIENT. V. ON ESTIMATING THE STORAGE CAPACITY REQUIRED TO BE PROVIDED. VI. CLASSIFICATION OF WATERWORKS. VII. IMPOUNDING RESERVOIRS. VIII. EARTHWORK DAMS. IX. MASONRY DAMS. X. THE PURIFICATION OF WATER. XI. SETTLING RESERVOIRS. XII. SAND FILTRA- TION. XIII. PURIFICATION OF WATER BY ACTION OF IRON, SOFTENING OF WATER BY ACTION OF LIME, NATURAL FILTRATION. XIV. SERVICE OR CLEAN WATER RESERVOIRS WATER TOWERS STAND PIPES. XV. THE CONNECTION OF SETTLING RESERVOIRS, FILTER BEDS AND SERVICE RESERVOIRS. XVI. PUMPING MACHINERY. XVII. FLOW OF WATER IN CONDUITS PIPES AND OPEN CHANNELS. XVIII. DISTRIBUTION SYSTEMS. XIX. SPECIAL PROVISIONS FOR THE EXTINC- TION OF FIRES. XX. PIPES FOR WATERWORKS. XXI. PREVENTION OF WASTE OF WATKK. XXII. VARIOUS APPLIANCES USED IN CONNECTION WITH WATERWORKS. APPENDIX I. BY PROF. JOHN MILNE, F.R.S. CONSIDERATIONS CONCERNING THE PROBABLE EFFECTS OF EARTHQUAKES ON WATERWORKS AND THE SPECIAL PRECAUTIONS TO BE TAKEN IN EARTHQUAKE COUNTRIES. APPENDIX II. BY JOHN DE RIJKE, C.E. ON SAND DUNES AND DUNE SANDS AS A SOURCE OF WATER SUPPLY. "We congratulate the author upon the practical commonsense shown in the preparation of this work. . . . The plates and diagrams have evidently been prepared with great care, and cannot fail to be of great assistance to the student." Builder. WATER SUPPLY, RURAL, A Practical Handbook on the Supply of Water and Construction of Water Works for small Country Districts. By ALLAN GREENWELL, A.M.Inst.C.E., and W. T. CURRY, A.M.Inst.C.E., F.G.S. With Illustrations. Second Edition, Revised. Crown 8vo, cloth 55. " The volume contains valuable information upon all matters connected with water supply. . . . It is full of details on points which are continually before water-works engineers." Nature. WELLS AND WELL-SINKING. By J. G. SWINDELL, A.R.I.B. A, and G. R. BURNELL, C.E. Revised Edition. Crown 8vo, cloth 25. 30 CROSBY LOCKWOOD & SON'S CATALOGUE. WIRELESS TELEGRAPHY: ITS THEORY AND PRACTICE. A Handbook for the use of Electrical Engineers, Students, and Operators. By JAMES ERSKINE-MURRAY, D.Sc., Fellow of the Royal Society of Edinburgh, Member of the Institution of Electrical Engineers. Fourth Edition, Revised and considerably Enlarged, 450 pages, with 195 Diagrams and Illustrations. Demy Svo, cloth. {fust Published. Net IDS. 6d. ADAPTATIONS OF THE ELECTRIC CURRENT TO TELEGRAPHY EARLIER ATTEMPTS AT WIRE- LESS TELEGRAPHY APPARATUS USED IN THE PRODUCTION OF HIGH FREQUENCY CURRENTS- DETECTION OF SHORT-LIVED CURRENTS OF HIGH FREQUENCY BY MEANS OF IMPERFECT ELECTRICAL CONTACTS DETECTION OF OSCILLATORY CURRENTS OF HIGH FREQUENCY BY THEIR EFFECTS ON MAGNETISED IRON THERMOMETRIC DETECTORS OF OSCILLATORY CURRENTS OF HIGH FREQUEMCY ELECTROLYTIC DETECTORS AND CRYSTALLINE RECTIFIERS THE MARCONI SYSTEM THE LODGE-MUIRHEAD SYSTEM THE FESSENDEN SYSTEM THE HOZIER- BROWN SYSTEM WIRELESS TELEGRAPHY IN ALASKA THE DE FOREST SYSTEM THE POULSEN SYSTEM THE TELEFUNKEN SYSTEM THE LEVEL AND OTHER SHOCK-EXCITATION SYSTEMS DIRECTED SYSTEMS SOME POINTS IN THE THEORY OF JIGS AND JIGGERS ON THEORIES OF TRANSMISSION WORLD- WAVE TELEGRAPHY ADJUSTMENTS, ELECTRICAL MEASUREMENTS AND FAULT TESTING ON THE CALCULATION OF A SYNTONIC WIRELESS TELEGRAPH STATION TABLES AND NOTES. ". . . . A serious and meritorious contribution to the literature on this subject. The Author brings to bear not only great practical knowledge, gained by experience in the operation of wireless telegraph stations, but also a very sound knowledge of the principles and phenomena of physical science. His work is thoroughly scientific in its treatment, shows much originality throughout, and merits the close attention of all students of the subject." Engineering. WIRELESS TELEPHONES AND HOW THEY WORK. By JAMES ERSKINE MURRAY, D.Sc., F.R.S.E., M.I.E.E., Lecturer on Wireless Telegraphy and Telephony at the Northampton Institute, London ; Fellow of the Physical Society of London ; Author of " Wire- less Telegraphy," and Translator of Herr Ruhmer's "Wireless Tele- phony." Second Edition, Revised. 76 pages. With Illustrations and Two Plates. Crown Svo, cloth Net is. 6d. How WE HEAR HISTORICAL THE CONVERSION OF SOUND INTO ELECTRIC WAVES WIRELESS TRANSMISSION THE PRODUCTION OF ALTERNATING CURRENTS OF HIGH FREQUENCY How THE ELECTRIC WAVES ARE RADIATED AND RECEIVED THE RECEIVING INSTRUMENTS DETECTORS ACHIEVEMENTS AND EXPECTATIONS GLOSSARY OF TECHNICAL WORDS INDEX. WIRELESS TELEPHONY IN THEORY AND PRAC TICE. By ERNST RUHMER. Translated from the German by J. ERSKINE-MURRAY, D.Sc., M.I.E.E., etc. Author of "A Handbook of Wireless Telegraphy." With numerous Illustrations. Demy Svo, cloth.. Net IDS. 6d. " A very full descriptive a count of the experimental work which has been carried out on Wireless Telephony is to be found in Professor Ruhmer's book. . , . The volume is profusely illustrated by both photographs and drawings, and should prove a useful reference Work for those directly or indirectly interested in the subject." Nature. "The explanations and discussions are all clear and simple, and the whole volume is a very readable record of important and interesting work." Engineering. WORKSHOP PRACTICE. As applied to Marine, Land, and Locomotive Engines, Floating Docks, Dredging Machines, Bridges, Shipbuilding, etc. By J. G. WINTON. Fourth Edition, Illustrated. Crown Svo, cloth 35. 6d. WORKS' MANAGER'S HANDBOOK, Comprising Modem Rules, Tables, and Data. For Engineers, Millwrights, and Boiler Makers ; Toolmakers, Machinists, and Metal Workers ; Iron and Brass Founders, etc. By W. S. HUTTON, Civil and Mechanical Engineer, Author of " The Practical Engineer's Handbook," Seventh Edition, carefully Revised and Enlarged. Medium Svo, strongly bound 155. STATIONARY AND LOCOMOTIVE STEAM-ENGINES, GAS PRODUCERS, GAS-ENGINES, OIL-ENGINES, ETC. HYDRAULIC MEMORANDA: PIPES, PUMPS, WATER-POWER, ETC. MILLWORK : SHAFTING, GEARING, PULLEYS, ETC. STEAM BOILERS, SAFETY VALVES, FACTORY CHIMNEYS, ETC. 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