HANDBOOK FOR GAS ENGINEERS AND MANAGERS. NEWB1GGING. EIGHTH EDITION, .Bgineering HANDBOOK FOR GAS ENGINEERS AND MANAGERS WILLIAM MURDOCH INVENTOR OF GAS LIGHTING. HANDBOOK FOR GAS ENGINEERS AND MANAGERS BY THOMAS NEWBIGGING D.Sc., M.lNET.C.E. EIGHTH EDITION, ILLUSTRATED LONDON : WALTER KING, OFFICE OF THE "JOURNAL OF GAS LIGHTING," ETC 11 BOLT COURT, FLEET STREET, E.G. 1913 gngineering Library . '' " : ; ij ,- .:.,.-. TO THE PRESIDENT, COUNCIL AND MEMBERS OF THE INSTITUTION OF GAS ENGINEERS IN THIS THE JUBILEE YEAR OF THE INSTITUTION I DEDICATE THE EIGHTH EDITION OF THE HANDBOOK 280137 NOTE TO THE EIGHTH EDITION. THE continual progress that is taking place in the apparatus, machinery, and methods of the Gas Industry has necessitated a revision of portions of the text and* the addition of much new matter to this edition of the Handbook. Whilst many new illustrations are introduced, it has been thought desirable to withdraw those suggesting designs for Public Illuminations, as makers in plenty of similar designs are now to the fore whenever the occasion arises for such displays. No effort has been spared to maintain the high standard of the work and its usefulness to Engineers and Managers, as well as to Students seeking entry into the profession. T. N. 5, NORFOLK STREET, MANCHESTER : -4 3. PRINCIPAL CONTENTS. (For Alphabetical Index, see end.) PAGE Introduction . . . . . . ,. . . ; i Coal . . . . . . ,. . . . 10 Chief kinds of Coal . . . . . . . n Storage of Coal . ... . . . . . . 16 Analyses of Coals . . . . .. . 17 Spontaneous Ignition of Coal . . . . . . 18 Gases Occluded in Coal ... . . . . . 19 -Testing of Coal for its Producing Qualities. . . . 20 Specific Gravity of Coal . . . . ,. .24 Coal Distillation - . . . . ... . 26 Gas Production ". . . . . .... 31 Retort House . . . . v . . . . 32 Retort Stack . . 38 Retorts .' . ... . . . ' .. 42 Heating of Retorts ........ 48 Inclined Retorts . . '. .... . .56 Machine Charging and Drawing . . . ... . 59 Vertical Retorts . . . . . . . * , 69 Elevating and Conveying Machinery . ... 73 Retort Stack-Bracing . . . . . "^ . . 77 Retort House Tools and Appliances . ... ,88 Hydrocarbon and other Gases and Vapours . . '. 90 Carburetted Water Gas . . . . .... 99 Coke Oven Gas . . . . . . .- . . TOO Pyrometers and Heat Recorders . . . . 101 Analysis of Furnace Gases . .< 102 PRINCIPAL CONTENTS PAGE Condensation ......... 105 Naphthalene .... ..... 106 Condensers ......... 112 Exhausters ......... 122 Steam Engines and Boilers . . . . . .126 Washers . . . . . . . . . 131 Tower Scrubbers . . . ..... 133 Washer-Scrubbers . . . . . . . .138 Centrifugal Washers . . . . . . . 143 By-pass Mains and Valves . . . . . . 145 Tar and Liquor Wells and Tanks . . . . _,..- 145 Purification ... ..... 148 Use of Air in Purification ....... 156 Claus's Process . . 158 Purifying House . . . . . . . 160 Purifiers .... . 161 Notes on Lime . ...... 174 Lime Burning ......... 176 Station Meters and other Indicating and Recording Apparatus 180 Gasholder Tanks 186 Gasholders . . . . . . . . . 208 Governors ......... 234 Main Pipes ... ..... 240 Main Pipe Joints ........ 245 Wrought-Iron and Steel Main Pipes 248 Laying of Main Pipes ....... 252 Explosions in Main Pipes ....... 258 Testing of Mains in the Ground . . . . . 259 Electrolysis of Main and Service Pipes .... 261 Discharge of Gas through Main Pipes .... 276 Service Pipes and Fittings ...... 290 High Pressure Distribution ...... 298 Public Lighting 301 High Pressure Lighting .305 Consumers' Gas Meters ...,,,, 315 PRINCIPAL CONTENTS xi Testing Meters . . . . . . . . . 321 Internal Fittings , . "... . . .... 336 Coal Gas Testing-Appliances and Methods . . . . 350 Tests for Impurities . .... . . . . . . 350 Notification of the London Gas Referees . . . . 360 Illuminating Power . ..... . . > . 381 Foreign and other (proposed) Home Standards of Light . 385 Jet Photometers . 393 Specific Gravity of Gas . . . . . . 397 The Gravitometer . . I . . . . . 404 Calorimetry . ... . . . . 406 Enrichment of Coal Gas . . . . . . 408 Public Illuminations . . -. . 410 Coloured Fires ......... 414 Use of Gas for Purposes other than Lighting . . . 416 Residual Products 418 Coke and Breeze . . . . . ... . 418 Coal Tar .... .... 420 Ammoniacal Liquor ........ 423 Sulphur Recovery . . . . . . . . 428 Cyanogen . 431 Coal Products . . . . . . . . . 440 Elementary Substances . . . . . . 454 Chemical and other Memoranda . . . . . 454 Specific Heat of Substances . . . . . . 465 The Gas Industry . . ...... . . 468 Golden Rules for Gas Managers . . . . . 479 Cost of Gas-works . . . v . 479 Bricks and Brickwork . . . % . . 486 Mortar and Concrete . . . - . . . . . 495 Iron, Steel, and other Metals ... . -. 497 Velocity and Force of the Wind . ., .... 508 Specific Gravity and Weight of Various Substances . . . 509 Office Memoranda ... . . . . . . 512 Epitome of Mensuration . . . . ... 520 xii PRINCIPAL CONTENTS PAGE Arithmetical and Algebraical Signs ..... 523 Approximate Multipliers . . . . . ' . . 524 Tables of Diameters, Circumferences, Areas of Circles, and Sides of Equal Squares . . . . . . 526 Weights and Measures ....... 533 French Weights and Measures Decimal System . . 539 Money Tables . . . . ... . . 545 Alphabetical Index ........ 549 ILLUSTRATIONS. FIG. PAGE 1. Coal Testing Apparatus ' J*. . . . . , 23 2. Specific Gravity Balance . ... . . 24 3. Ground Floor Retort House (single) and Coal Store . 32 3 ' " " ** * ji 4. Ground Floor Retort House (double) and Coal Stores . 33 5. Stage Floor Retort House and Coal Stores . 34 6. and Coal Store . . . 35 7. House for Inclined Retorts f .... 36 8. . . 37 9. Bench of Retorts * . .40 10-13. Retorts, Round, Q -shaped, and Oval ... 43 14. Brick and Tile Retort, section . . . . . 45 15. Herring's Q Retort, section . . . . . 45 16. Bench of Retorts and Producer . . . -49 17. with Hearth . . 50 18. \\dth Drip Plates . 51 19- 52 20. . 53 21-22. Retort House and Stack of Retorts '. . . 54 23. Love's System of Inclines . . . iT ~ . . 58 24. The West Power Stoker . . . . . 60 25. The Arrol-Foulis Power Stoker . . . . .61 26. The Fiddes-Aldridge Power Stoker . .. . . 63 27. The De Brouwer Power Stoker . . . .64 28. Dempsters' "Stoking Machinery . * . \~ 65 29. The Drake Charging Machine * " . . . 66 30. The Dessau Vertical Retort Installation . . 68 xiv ILLUSTRATIONS FIG. PAGE 31. The Woodall-Duckham Vertical Retort Installation . 70 32. The Glover- West ,, ,, . 71 33. Tar Furnace ........ 76 34-36. Buckstaves, sections and elevations . . 7/~79 37. Coke Slaking Arrangement . . . . -79 38. Furnace Ashpan ....... 79 39-42. Retort Mouthpiece, Lid, and Fittings 81 43-44. Bridge and Dip Pipes ...... 84 45-47. Hydraulic Main, various sections .... 85 48. Livesey Hydraulic Main, section . . ';-.... 85 49. Hydraulic and Back Mains and Connections . , 86 50. Apparatus for removing Tar from Hydraulic Main . 87 51. Charging Scoop 89 52. Discharging Rake . . . . . . .89 53. Auger .89 54. Ashpan Rake . . . . . . . .89 55. Shovel 89 56. Fire Tongs ........ 89 57. Pricker ......... 89 58. Bridge Pipe with Wing Valve 93 59. The Orsat Apparatus for Analysing Furnace Gases . 103 60. Horizontal Condenser for Small Works . . .112 61. Graham's Horizontal Condenser ..... 113 62. Vertical Condenser . . . . . . .114 63. Annular Condenser . . . . . . .114 64. ....... 115 65. Battery Condenser ....... 116 66-67. Drory's Main Thermometer ... . 122 68. Beale's Exhauster 123 69. G Wynne's Exhauster . . . . . .124 70. Waller's Three-Blade Exhauster .... 124 71. Four-Blade ,, . . . . . 124 72. Anderson's Exhauster ....... 125 73. Cleland and Korting's Steam Jet Exhauster . . 126 74. Tower Scrubbers = ...... 133 ILLUSTRATIONS xv FIG. PACE 75. Gurney Jet . 134 76. Water or Liquor Feeding Arrangement . . 136 77-78. Tower and Washer-Scrubbers . . 136-7 79. " Standard " Washer-Scrubber . . . . 139 80. " Eclipse " Washer- Scrubber ". . . . .140 81. " Brash " Washer-Scrubber . . -. . / 141 82. " Whessoe " Washer-Scrubber . . ... . 141 83. Walker's Purifying Machine . ... . . . 142 84. Kirkham, Hulett, and Chandler's Centrifugal Washer . 144 85-86. Tar and Liquor Separator . . . . . 146 87-89. Purifying House and Purifiers - . . 160-1 90. Elevating Apparatus for Oxide and Lime . . . 162 91-92. Purifying House and Purifiers .... 163 93. Purifiers, Centre and Four-way Valves . ... 164 94-98. Goliath Lifting Machine for Purifier Lids . 165-71 95. Green's Purifiers . . . . . . . 166 96. Tray or Grid for Purifiers . . . . 168 97. Spencer's Hurdle Grids . . . . . . 169 99. Hydraulic Ram for Lifting Purifier Lids . . . 171 100. Dry Centre Valve . ^ . . . . . . 172 101-102. The Week Valve . . . . . '. 172 103-104. Tunnel Kilns for Lime Burning . . . . 178 105-106. Flare . . . 179 107. Station Meter, cylindrical . . . . . , 181 108. Station Meter, rectangular . . . . . 181 109-110. Pressure Gauges . . . . . 184 in. Differential Pressure Gauge ... . . 184 112. King's . . . . . .- . 184 113. Crosley's Pressure and Exhaust Register . " . . 185 114. Wright's Pressure Register . . . . , 185 115. Gasholder Tank, Brick and Puddle . . . . 186 116. Cast-kon . . . . . 186 117. Annular . . . . ... 186 118. Natural Slope of Earths . . , . . .^191 119. Trammel for Gasholder Tanks . '-. - . . 193 xvi ILLUSTRATIONS FIG. PAGE 120-121. Inlet and Outlet Pipes ..... 194 122. Gasholder, Single Lift ...... 209 123. Three Lift (telescopic) .... 209 124. Gadd and Mason, Three Lift . . . 210 125-126. ,, on E. L. Pease's System . . . .211 127. Livesey's Hydraulic Seal ...... 212 128-131. Braddock's Station Governors . . . 235-7 132. Cowan's Station Governors . . . . 238 133. Peebles's 238 134-135. Peebles's District or Differential Governor . 239-40 136. Turned and Bored Joint, with recess .... ,243 137. ,, without recess . . . 243 138. 246 139-140. Open Joints 246 141. India-rubber Joints ....... 247 142. Ball and Socket Joint ...... 247 143. Expansion Joint v . . , . . . . 247 144. Bends, Tees, Crosses, Sockets, etc. .... 249 145. Mannesmann Steel Tube with open Joints . . . 250 146. ,, ,, with rigid Joints . . . 250 147. The " Kimberley " Collar . 252 148-149. Syphon or Drip Wells . . . . . 255 150. Bag for Plugging Mains ...... 258 151. Lyon's Main Testing Arrangement .... 260 152. Hulett's Service Cleanser ...... 291 153. Cowan's ,,...... 292 154. Hutchinson's ,, ,, . . . . . 292 155. Service Pipes and Fittings ..... 295 156-157. The Bryan Donkin Compressor . . . 299-300 158. Milne's Rotary Compressor ..... 301 159-61. Street Lamp Posts ...... 302 162. Hutchinson's Lamp Service Cleanser ... . . 303 163. Bray's 1907 S.L. Burner ...... 303 164. Welsbach Lamp ....... 304 165. Bland Street Lamp 305 ILLUSTRATIONS xvii 166. New Inverted Incandescent Lamp Coy.'s Lamp . ^ 305 167. Keith-Blackman's Compressor . . ... fc . 308 168. 300o-Candle Power Suspension Lamp . . .". . , 309 169. Lamp Fitted with Raising, Lowering, and Traversing Gear 310 170. Pharos-Welsbach Compressor . . . . . 311 171- Gas Lamp ... . . 312 172. \,, High Pressure Air Lamp . . % 1 312 173-174. Wet Meter . . . . -; , . 315 175-176. Dry Meter . ' '"> . .= . . . 316 177. Warner and Cowan Measuring Wheel . ^ .-, . 316 178. Sanders and Donovan Meter .. . .. , . . 317 179. Greenall and Heaton's " Positive " Meter .. . . 319 180. Parkinson's Motive Power Meter . . . 319 181. Apparatus for Testing Meters . . . . . 321 182. Cowan's Ventilating Globe Light . . . 342 183. Strode 's Ventilating Sun Light . . . . 342 i84-i84A. Milne's " Nonpareil " Ventilating Gas Burner . 343 185. Sulphuretted Hydrogen Test v " . . . . 352 186. Sulphur Test . . ; * . I . . . 353 i87~i87A. Sheard's Apparatus for Estimating Carbon Dioxide, Ammonia, and Sulphuretted Hydrogen ... . 354 188. Harcourt's Colour Test . . ...... ^ 356 189. Harcourt's lo-Candle Pentane Lamp . . . . 361 190. The Metropolitan Argand Burner, No. 2 ... 364 191. Referees' Sulphuretted Hydrogen Test . . . 365 192. Referees' Sulphur Test . . . .... 368 193. Boys' Gas Calorimeter . . . .- . . 373 194. Graduated Vessel , . . . J . . 375 195. Referees' Street Lamp Pressure Gauge . - . . 378 196. Referees' One-twelfth Cubic Foot Measure . . . 379 197. Harcourt's Aerorthometer . . . . . . 380 198. Letheby-Bunsen Photometer . . . . - _ ._. 382 199. The Cai eel Lamp . . . . . . . 385 200. Met hven's Standard . . . . . ' -. 387 201. Methven's Carburettor . . ... . . 387 xviii ILLUSTRATIONS PAGE 202. Harcourt's i-Candle Pentane Lamp . . . . 389 203. Dibdin's lo-Candle Pentane Argand .... 390 204. Lowe's Jet Photometer . . . . . . 393 205. Scale for ,, ,, ...... 394 206. Sugg's Illuminating Power Meter .... 394 207. Thorp and Tasker's Jet Photometer . . . . 395 208. Letheby's Specific Gravity Apparatus . . . 399 209. Wright's Specific Gravity Balloon .... 402 210. Lux's Specific Gravity Balance ..... 403 211-212. Simmance and Abady's Gravitometer ' . . . 404 213. Coke-Breaking Hammer ., . . . . . 419 214-216. Apparatus for the Manufacture of Sulphate of Ammonia, and the Recovery of Sulphur . . . 424 217. Stephenson's Apparatus for Testing Spent Oxide . . 437 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS AND MANAGERS. COAL GAS. INTRODUCTION. THE art of coal gas manufacture is more than a hundred- and-fifteen years old. Between 1792 and 1798, William Murdoch, its inventor, was engaged, first at Redruth in Cornwall, then at Old Cumnock in Ayrshire, and finally at Birm- ingham, in experimenting with different coals, and in devising apparatus for their distillation. In 1797-98 lighting by coal gas became an accomplished fact, for Murdoch, by means of his experimental plant, first lit up his dwelling-house at Old Cumnock with the new illumrnant, and, on his removal to Birmingham in the latter year, having erected an apparatus on a considerable scale, he lighted a portion of the premises of Boulton, Watt, & Co., Soho. The circumstance that coal would yield an illuminating gas was known long before that time. Natural gas, as it was found to issue from the bowels of the earth in particular districts where coal deposits existed, had been the subject of frequent observa- tion, and its lighting power proved by actual trial ; but no practical application was made of the knowledge till Murdoch bent his mind to the study of the subject. KING'S HANDBOOK FOR GAS ENGINEERS n-years is a long time in the history of an industry longer than one exactly realizes at a first glance. The lapse of so many years since the discovery and application of gas- lighting confers something of the venerableness of age upon the art. This is more obvious when cognizance is taken of the initiation of other arts, and the advances made in them, and not less so in the progress of the sciences, within that period of time. Take railways, for example. As compared with these, gas- lighting is old, for it had a start in life of thirty years before them. Nay, even the steam engine : that is no older than the art of gas- lighting, and much of its initiation and perfecting was due to the same fertile brain, for Murdoch was Watt's right-hand man at Soho, and invented the D slide-valve, the " sun and planet " motion, and the oscillating steam cylinder. As for the telegraph, the telephone, electric lighting, and wireless telegraphy, these are but 'of yesterday the younger sisters of the useful arts. Even the science of chemistry was only emerging from its swaddling clothes when gas-lighting was invented. Although Murdoch had thus realized his dream of employing the gas produced from coal as a lighting medium, there was still much to be done to render the new illuminant acceptable. The impurities in the crude gas were found to be many and objection- able, and means and appliances for their elimination had to be devised. Suitable pipes for the conveyance of the gas to the point of combustion were also required. Murdoch devoted much time and effort in these directions, washing the gas with water, and employing other means to purify it, and using tinned-copper and iron tubes for its distribution. Other ingenious minds were early at work in the promising field thus opened out to the labourer. Lebon, in France ; Winsor, at Frankfort, and later in London, where he projected "The National Light and Heat Company," afterwards incorporated by Royal Charter as " The Chartered Gaslight and Coke Company ; " Samuel Clegg, who had been a pupil or apprentice at the Soho Works, Birmingham ; Dr. Henry, of Manchester ; Northern, of Leeds ; Pemberton, of Birmingham ; John Malam ; Samuel Crosley and T. S. Peckston, of London ; Reuben Phillips, of Exeter ; and Melville, of Newport, Rhode Island, U.S.A. Chief amongst these pioneers was Samuel Clegg, who possessed a rare mechanical skill, combined with much shrewd common PIONEERS OF GAS LIGHTING sense. In 1805 he began to apply himself to the invention and construction of gas apparatus, and introduced the new method of illumination into many large establishments in different parts of the country. Clegg invented the hydraulic main, and the lime purifier as a separate vessel, though Mr. (afterwards Dr.) William Henry, of Manchester, the distinguished chemist, was the first to suggest the use of lime as a purifying medium. Clegg also invented the wet gas meter (afterwards improved by Samuel Crosley) , and evinced infinite resource in improving the apparatus of the gas factory in every department. In these respects he was ably seconded by John Malam, who now stepped in and perfected the wet meter in such a way as to render it one of the most ingenious measuring appliances of this or any past age. Malam also invented the first dry meter ; but this appliance, in the form now in use, was the invention of William Richards in the early 'forties, and afterwards improved by Thomas Glover. The arrangement of four purifiers, which, with the centre valve, holds the field to this day, was also the product of Malam's ingenuity. The new art of gas-lighting was fortunate in many of these its early exponents. The " Chartered " vessel, launched by Winsor and others associated with him, floundered about for a while in a troubled and, at times, a boisterous sea, due, no doubt, to the inexperience, but largely also to the incompetence, of some of those in charge ; till, at length, the skilful pilotage of Samuel Clegg, who eventually assumed command (in 1813), brought her into smooth waters. It is not surprising tfyat mistakes were made at first, and that immediate success failed to attend the early efforts of the pro- moters of gas enterprise. The art was a new one ; nothing akin to it was there to serve as a model or afford direction and guidance. All the appliances of manufacture, purification, storage, and dis- tribution had not only to be made but invented. The prejudices of the public, too, had to be overcome. Winsor, with the best intentions, scarcely helped to remove those prejudices. His enthusiastic advocacy, with something of foresight, had in it much of unwisdom. He projected the wildest schemes of gas enterprise ere yet the public even the immediate public who listened to his harangues and read his pamphlets had had time or opportunity to grasp the importance of the subject. B 2 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Gradually, however, confidence was established. Distrust gave way to admiration ; for, under the daily improving manage- ment, the new artificial light was shown to be not only cheaper and safer, but vastly superior in lighting power, cleanliness, and handiness to anything previously in use. Other companies were soon established in the Metropolis. One by one (like stars coming out at dusk) the larger towns of the kingdom had each its gas company, lighting the public streets and thoroughfares, and supplying its growing number of private consumers. Thus the new art grew from precarious childhood into youth and sturdy manhood. It is not too strong an assertion to make, that gas-lighting, during the century of its existence, has proved one of the greatest boons enjoyed by civilized humanity, and no industry that can be named has had a steadier or more abundant success. This success has been due to two main causes : The inherent utility and value of the invention, and the skill, probity, and business capacity of most of those who, both in the earlier years and later, took a leading part in its furtherance. The progress which has been made during the century in the machinery of gas manufacture is very striking. This has not been a mere advance in the capacity of the various appliances due to the growing demand for gas-lighting on the part of consumers, but is a positive revolution in constructive detail. In the first days of the invention the retorts used were of iron, and were placed in the vertical position in the furnace. This was the mode of erection that would naturally be adopted at first, inasmuch as it lends itself to convenience in depositing the charge. But it was very soon found that the difficulty of withdrawing the residual coke by way of the mouth was such that an alteration in the position was an absolute necessity. Accordingly, no long time elapsed before the retorts began to be laid, first, at an inclination, and then horizontally ; and instead of only one retort, two, three, and eventually five, were set together and heated, at first by two furnaces, but later by one furnace only. This was a manifest improvement, and it held its ground for many years. At the present time, in most gas-works, settings of six, seven, eight, nine, and even ten and twelve retorts are in vogue. Gradually^it was found that a high temperature was necessary RETORTS AND MOUNTINGS for economical distillation, inasmuch as with the lower ranges of temperature it was seen that, instead of the evolution of gas, the products were largely in the liquid form. The retorts themselves were originally of cast-iron, and con- tinued so to be till well into the middle of the century. As the advantages of the higher temperatures of distillation began to be recognized, these were gradually replaced, though not without a struggle, by retorts made of moulded fire-clay, or built up of segment al bricks and tiles. Instead of direct firing, the regenerative method of heating the retorts, whereby the solid coke is converted into gaseous fuel (CO), is generally applied, and with marked advantage, from every point of view. The ironwork mountings of the retort bench have undergone considerable modification and improvement during the century. Self-sealing lids, the invention of Robert Morton, for the retort mouthpieces, have been introduced. The ascension, bridge, and dip pipes have been modified and enlarged ; and the hydraulic main ,is now made of wrought -iron or mild steel, and of various improved patterns. Subsidiary or foul mains and tar mains have been added, by which the gas and liquid products are conveyed separately away. The problem of the application of machinery in gas manu- facture, and the consequent saving of manual labour, has been completely solved. This was the dream of the early gas engineers, some of whom attempted it without success. With an ingenuity and a persistency deserving of all praise, Mr. John West devised machinery for stoking, and has, year by year, improved both his hand and power charging and drawing machines. Mr. William Foulis was also a pioneer in the same direction, and his machinery for that purpose finds wide acceptance. Later successful inventors of charging and discharging machinery are R. Dempster & Sons, Fiddes & Aldridge, Drakes, and Bronder (of New York), whose machinery charges and draws four retorts at once. Inclined or sloping retorts, set at an angle of 30 to 33 degrees, are largely in use in the carbonizing department of gas-works. Settings of this kind, employed by M. Coze, of Rheims, attracted much attention about twenty-two years ago, and have been adopted at many gas-works in this country and abroad. In Love's arrange- ment the retorts are set at an inclination of 45 degrees. 6 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS The inclined system simplifies the operations and mitigates the labour in the retort house, besides increasing the productive capacity of the available floor area. The idea of employing retorts set in the inclined position was not new, but an impetus was given to the system by its adoption, under improved conditions, at Rheims. After Murdoch, Andrew Scott of Musselburgh, about the year 1874, invented a system of conical retorts . set in the vertical position (see King's '-Treatise," vol. i. p. 236). The bottom end of the retort rested in a trough containing water, which acted as a seal to prevent the escape of the gas, whilst allowing the coke to be easily withdrawn. Within very recent years various other systems of carboniza- tion in retorts set vertically have come to the front, chiefly (i) the Dessau system, (2) that of Woodall & Duckham, and (3) that of Glover & West. In the first, the charging and drawing are intermittent ; in the two latter, continuous. With these, satisfac- tory results have been achieved, so that continuous carbonization may be considered as solved. Machinery and appliances for the conveyance of coal and coke, and the lime and oxide used in purification, from one point to another, are being widely and successfully applied, and are fast becoming important labour-saving agencies. The process of washing the gas has been advocated and con- demned by various authorities at different periods. Washing was common enough in the early days, but by reason of a supposed deteriorating effect on the illuminating power it was discredited for a time, and scrubbing by an intercepting material presenting a large area of wetted surface to the gas was preferred. The view has eventually prevailed that washing as well as scrubbing is indispensable, and the result is that apparatus to accomplish this object has been introduced by various makers with excellent effect. It is now universally admitted that washing and scrubbing, both with ammoniacal liquor and clean water, are absolutely necessary in order to remove the lighter tars (the heavier tars having been deposited in the condenser) and arrest the ammonia impurity, as well as to eliminate a proportion of the sulphuretted hydrogen and carbon dioxide from the crude gas before it reaches the purifiers proper. It may be safely asserted that the gas of to-day, PURIFICATION BY LIME AND OXIDE as supplied to consumers, is absolutely free from the objectionable ammonia, with the further advantage that this is secured for sale at the gas-works. The same can be said as regards sulphuretted hydrogen. In all well-managed gas-works this impurity is absent from the distributed gas. Lime was the only medium employed for arresting sulphuretted hydrogen In the earlier days of gas-lighting, till Mr. F. C. Hills introduced the use of hydrated peroxide of iron for that purpose ; and although this has no affinity for carbon dioxide, the latter impurity is taken out by passing the gas through lime, either in the first instance or in the last stage of purification. The advantage of using the oxide of iron is its economy, as it can be revivified by exposure to the air after it has become foul, and can be used over and over again, till its bulk has been about doubled by the presence of free sulphur. It also secures another important desideratum the reducing of the mountains of foul or spent lime that would otherwise accumulate in the gas yard, and for which, in some districts, there is no great demand on the part of agriculturists. True, a process of spent lime revivification has "been invented by Mr. George Hislop ; but although this is efficacious in action, it has not been widely adopted. With the advent of Mr. (afterwards Sir) George Livesey as Engineer-in-Chief of the SoUth Metropolitan Gas Company, a new era in gasholder construction may be said to have begun. It is interesting to note the progress made in his several remarkable structures. The first of his notable holders, erected at the Old Kent Road Station, consists of two lifts. It is 180 ft. in diameter, and the two lifts rise to a height of 90 ft. when fully inflated, the capacity being 2 million cub. ft. His next holder at the same station has a diameter of 214 ft., is in three lifts, and stands when full at a height of 160 ft., having a capacity of 5^ million cub. ft. The third one, erected at East Greenwich, is in four lifts, 250 ft. in diameter, and rises to a height of 180 ft., its capacity being 8J million cub. ft. The latest and largest gasholder belonging to the Company is also erected at East Greenwich. This is a veritable monster in size, being 300 ft. in diameter, having no fewer than six lifts, and rising when inflated to a height of 180 ft. ; its capacity being 12 million cub. ft. But it is not their size only which makes these enormous vessels remarkable ; their structural features are equally note- 8 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS worthy. Instead of the usual guide-framing, consisting of columns or standards of large bulk and weight, Sir George Livesey in his later structures introduced a guide-framing consisting of com- paratively light members, the standards being braced together by diagonals and horizontal struts. Although the two holders last referred to are of four and six lifts respectively, the guide-framing is not carried up to the full height reached by the inflated vessels. In the first, the inner or top lift rises beyond the framing ; and in the second, the two innermost lifts ascend above the summit of the framing their stability under wind pressure being sufficiently assured on cupping by the limited guide-framing applied. It is safe to assert that it never entered into the dreams of the most advanced gas engineers of the first half of the century that holders of anything like the enormous proportions named would be called into existence. Perhaps there is neither the scope nor the necessity in the provinces for holders of the size of the last named, but Mr. Charles Hunt, some years ago, before his retirement from the Windsor Street Station of the Birmingham Corporation Gas- Works, erected two with a capacity of 6J million cub. ft. each. These are in three lifts, rising to a total height of 150 ft., the diameter of the outer lift being 236 ft. in each instance. The holder just completed at the Bradford Road Station of the Manchester Corporation Gas- Works, and designed by Mr. J. G. Newbigging, the engineer, is in four lifts, the diameter of the outer one being 282 ft. When fully inflated the holder reaches a height of 182 ft. and its capacity is close on loj million cub. ft. The tank, which is of brick, is 285 ft. in diameter and 43 ft. deep. A remarkable innovation in gasholder guiding, by which the upper framing is dispensed with altogether, is due to the inventive genius of Mr. William Gadd, of Manchester. Mr. Gadd solved the problem in a variety of ways. First, by means of torsional and tensional gearing fixed round the tank, and attached to the holder or floating vessel at its base ; but more especially by the introduction of spiral guide-rails fixed to the sides of the tank or attached to the sides of the holder in a diagonal direction. The simplicity of this latter device is so self-evident that it is matter for surprise it had never been previously applied or thought of. The first holder of this class was erected at Northwich, in Cheshire, GASHOLDERS AND DISTRIBUTION by Clayton, Son, & Co., Ld., of Leeds, having been designed from the inventor's patent specification by the present writer. As frequently happens in other cases, there were other minds simultaneously engaged in the solution of the problem of guiding holders without upper framing. Mr. E. L. Pease, of Stockton- on-Tees, invented a system of guiding by means of wire-rope gearing ; and Mr. J. W. Terrace, of Brechin, also devised a means of guiding by shafting, screws, and wheels. Mr. Gadd's, however, was the patent first in the field. In the distribution department, improvements have been made from time to time. The open main joint, filled either with lead or some kind of cement caulking, was general down to the introduction of the turned and bored joint by Mr. Alfred King, of Liverpool, about the year 1826. This latter was without question a step in advance, and although there are engineers who still prefer the open joint, the preference arises more from prejudice than experience and knowledge. The turned and bored joint, with a recess in front for filling with cement or lead, is the most perfect joint possible for cast-iron main pipes laid in stable ground. Where t;he ground is liable to subsidence from any cause, wrought iron and steel main pipes, with screwed, flanged, rigid and open joints, are now extensively used. In street lighting a marked advance has been witnessed. Per- haps this is due to some extent to the threatened competition of the electric light. Years ago Mr. William Sugg introduced his large argands for street lighting. These undoubtedly gave a magnificent light, but the difficulties attending the regulation of the flame at varying pressures proved an impassable obstacle to their success, and they were finally abandoned. These were succeeded by the triform arrangement of large flat-flames, introduced almost simultaneously by Mr. Sugg and Mr. George Bray. For the illumination of streets, squares, and other wide open spaces, they were admirably adapted. The Welsbach system of incandescent gas-lights, introduced in the year 1887, has created a veritable revolution both in street and domestic lighting. The success of the invention has been as great as it is deserved. Not only is gas economized by its use, but the illuminating value of the light is increased to the extent of 300 to 400 per cent., and even more than this where high pressure is applied. Gas at a pressure of 2 to 3 Ibs. per square inch has io NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS an efficiency with the incandescent burner of 60 candles per cubic foot. The use of gas for cooking and heating, for the production of motive power, and for workshop purposes, has made vast strides of recent years. Fires, stoves, and ranges of all sizes and of excellent design, are produced by a number of first-class makers. The Otto gas engine, as made by Crossley Brothers, settled beyond question the economy and value of gas for motive power. Other makers of similar engines of great excellence are numerous. In the application of gas to industrial uses generally, the ingenuity of the late Mr. Thomas Fletcher found an outlet. In all these directions the field may be pronounced limitless. The invention and introduction of the prepayment meter has encouraged the use of gas by the poorer class of consumers, and here also it is difficult to conceive of a limit to gas enterprise. In no department of the gas industry has there been so remark- able a development as in that of dealing with the residual products. There is absolutely no waste in a well-managed gas-works. Every- thing is utilized, even to the dross yielded by the furnaces. This much can hardly be asserted of any other industry in existence, and this fact should be borne in mind by those who are sometimes inclined to decry the administrators of gas undertakings. The tangible result of it all is that gas property has attained to a reputation for value and stability scarcely exceeded by any other class of investment ; and, competition notwithstanding, there is ground for confidence that it will continue to maintain its deserved popularity. COAL. The geological position of coal in the earth's crust is shown in the annexed tabular view of the trias, permian, and carboniferous series in England and Wales, by Professor Hull : ( K>ur>pr / Red mar1 ' ' r \Lower Keuper sandstone. New red sandstone or trias . . -j (Upper mottled sandstone. Bunter ^ Conglomerate beds. (Lower mottled sandstone. COAL-MEASURES ii 'Upper red sandstone of St. Bees, etc. Upper and lower magnesian limestones and marls of the Northern counties. Permian rocks { Lower red sandstone of Lancashire, Cumberland, and Yorkshire, etc. (on the same horizon with) Red sandstones, marls, conglomerates, and breccia, of the Central counties and Salop. {Upper coal-measures, with limestone and thin coal seams. Middle coal - measures, with thick coal seams. 'Lower coal-measures, or Gannister series, with thin coal seams and lower carboni- ferous fossils. Carboniferous rocks Millstone grit, with thin coal seams. or Yoredale rocks. T IVlUlblXme gill, W1LU. U1J ^2 f i Upper limestone shale, 3 Carboniferous limestone with shales, sand- stones, and coal in the Northern counties I and Scotland. \ Lower limestone shale. Old red sandstone and Devonian rocks. The area of the coal-measures in the United Kingdom is as follows : Area of Coal-Measures. Entire Area of Country p roport j on Situation. Square Miles. Acres. Acres. Square Miles. 01 coal to the whole. In England . 6,039 3,864,960 31,770,615 49,643 i-8th In Scotland & Islands, exclusive of Lakes } 1,720 1,100,000 18,944,000 29,600 i-i8th In North Wales In South Wales 210 950 134,400 > 608,000 S 4,752,000 7,425 i-6th In Ireland 2,940 1,881,600 20,399,608 31,874 i-nth In Islands i,H9,i59 1,748 Total . H,859 7,588,960 76,985,382 120,290 | Exclusive of wood-coal and lignite formations, and some small undefined areas. The chief kinds of coal in the United Kingdom are Cannel or Parrot Coal. This is the richest gas-producing coal, and is easily distinguished by its hard, smooth texture. The best varieties are found hi different parts of Scotland, in Wales, and at Wigan and Newcastle or their neighbourhood. The latter two yield coke of fair quality ; that from the other is less valuable, and much of it is useless as fuel. 12 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Bituminous Coal. For gas- producing purposes the coal most suitable is the bituminous class, which includes caking, splint, cherry, and other coals, not necessarily containing bitumen, but because of their resemblance to that substance under heat. It is found widely distributed throughout the kingdom, in Yorkshire, Lancashire, Cumberland, Northumberland, Durham, Derbyshire, Staffordshire, Gloucestershire, Somersetshire, portions of Scotland and Wales. It yields coke generally of excellent quality. Anthracite or Glance Coal. This is chiefly Welsh, containing a large proportion of fixed carbon (over 90 per cent.) and but little volatile matter. It glows rather than flames in burning, and is almost smokeless. It is excellent for steam-raising purposes and domestic use where a good draught is available, but is quite useless for the production of illuminating gas. Lignite or Brown Coal. This is found at Bovey Tracey, in Devonshire, in a small field near Lancaster, and near to Lough Neagh, in Ireland. It yields but little gas, and that of a low illuminating power and very unpleasant odour. In distillation, it gives off a large quantity of water charged with acetic acid, and the residual coke is valueless as fuel. It is, therefore, of no great interest to the gas maker. The tables annexed show the specific gravity of coals, the chief substances of which they are composed, and their yield of coke per cent : NEWCASTLE COALS. Name of Coal. If d o XI 1 J 1 Ash. ! Coke. ft n u C/5 s Willington _ 86-81 4-Q6 1-05 0-88 5'22 i -08 72-19 Tanfield . 1-26 8.V58 5-3I 1-26 1-^2 4-39 2-14 65-13 Bowden Close . 84-92 0-96 0-65 6-66 2-28 69-69 Haswell Wallsend 1-28 6-68 1-42 0-06 8-17 0'20 62-70 Newcastle Hartley 1-29 81-81 5'5o 1-28 1-69 2-58 7-14 64-61 Hedley's Hartley 80-26 5-28 ri6 178 2-40 9-12 72-31 Bates's West Hartley 1-25 80-61 5-26 1-52 6-51 4*25 West Hartley Main 1-26 81-85 5'29 1-69 I-I3 7'53 2-51 59*20 Original Hartley 1-25 81-18 5-56 072 1-44 8-03 3-07 58-22 Average of 18 samples from different mines 1-25 82-12 5'3i i-35 1-24 5-69 377 60-67 VARIOUS COALS LANCASHIRE COALS. i 1 t> d 1 g ti 8 Name of Coal. v > 1 1 | 1 g Ash. Coke. | "0 ffi 2 w o I nee Hall Company's Arley -27 Haydock, Rushey Park -32 Blackbrook, Little Delf -26 82-61 77-65 82-70 5-86 5-53 5'55 1-76 o - 8o 0-50 1-73 1-48 1-07 7-44 10-91 4-89 3-68 4-31 64-00 59-40 58-48 Wig an Four Feet . -20 78-86 5-29 0-86 1-19 9-57 4*23 6o'oo Cannel . '23 79'23 6-08 1-18 7-24 4-84 60-33 Caldwell and Thomp son's Higher Delf . 1-27 75-40 4-83 1-41 2-43 19-98 5*95 54'20 Averagte of 28 samples from different mines . i 1*27 77-90 532 1-30 1-44 9-53 4-88 ; 60-22 DERBYSHIRE COALS (Fiddes). Earl Fitzwilliam's Elsecar 1-296 81-93 4-85 1*27 0-91 8-58 2-46 6r6o Holyland and Co.'s Elsecar . . . 1-317 80-05 4'93 1-24 ro6 8-99 3-73 62-50 Butterley Co.'s Langley . 1-264 77*97 5*58 0-80 1-14 9-86 4-65 54'9o Staveley .... 1-270 79-85 4-84 1-23 0-72 10-96 2-40 57-86 Average of seven samples from different mines . 1-292 79'68 4-94 I'4I I'OI 10-28 2*65 59-32 GLOUCESTERSHIRE COALS. Coleford High Delf (Forest of Dean) . 219 78-810 5-303 1-750 2-062 9-055 3-020 63-97 "SIS 76-502 1-090 1-669 8-659 6-700 62-60 "331 74-410 4-470 0-700 2-370 8-840 9'2IO 59-76 '354 74-464 5-292 0-511 2-667 6-831 10-235 60-36 Trenchard . "354 80-709 5*425 0-735 1-271 7-060 4-800 63-38 New Bowson, Cinderford 332 76-860 5-430 1-680 1-940 9-330 4-760 58-24 Parkfield ra 307 '374 82-069 5-250 5-613 1-260 0-940 0-850 1-457 9'ioo 6-391 4-230 3-530 59'22 60-97 Hanham . 277 75-340 4-630 0-630 2-440 548o 11-480 58-86 Warmley . 304 82-410 4-870 0-770 0-870 5-230 5-850 7 I " I 5 i ! SCOTCH COALS. Boghead . . WaUsend Elgin X'2l8 I'200 63-930 76-090. 8-858 5-220 0-962 1-410, 0-320 1-530 4-702 5-050 21'222 IO-700 31-70 Grangemouth . Eglinton. I-290 1-250 80-080 5-280 6-500 1-350 1-550 1-420 1-3801 8-580 8-050 3'520 2-440 , 56-60 54'94 i I 4 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS WELSH COALS (Fiddes). a 1 a g j Name of Coal. tD ,0 o" I ^ Ash. Coke. 2 ctf -M x 1 * C/3C3 o B * w O 1 r Aberaman, Merthyr . 3 00 90-940 4-280 1*2X0 1*180 0*940 1*450 85*00 Aberdare Co., Merthyr *3IO 88-280 4-240 1*660 0*910 1*650 3260 85*83 Anthracite (Jones & Co ) -375 91-440 3-460] 0*210 0-790 2*580 1-520 92*90 Coleshill . i '290 73-840 5-140 1-470 2*340 8-290 8-920 56*00 Llantwit . '273 77-410 5*553 0*560 2*365 12*062 2*050 64*70 252 77-310 5-642 0-420 2*037 10*366 4*225 58*82 Nantgarw Llantwit '326 79*130 5*610 0*700 3*450 7-330 3*780 61*67 Rhos Llantwit '282 76*995 5*455 0-700 1*643 12-875 2*332 63-30 '302 75*452 5*497 0-840 2*312 13-023 2*876 ; 63-03 '302 73*4io: 5*507 0*350 2-414 14-276 4'043 Holly Bush . '269 80*134:5*645 0*518 1 2*279 8*522 3*502 74*42 Tyr Filkens. '368 82*117 5*054 0-595 2-537 5-794 3*903 64-86 Llanhilleth . '274 87-640 6*085 1*120 1*636 2*209 1*310 7039 Aber Rhondda 320 80-675 5-082 O-giO 3-675 2-763 : 6-895 70*81 Pontypridd . j "311 79*820 5*470 0*700 j 3 950 3*750 6*310 65-80 Wallsend . { -317 78*270! 5*380 0*770 1*860 8-900 4-820 66*00 Energlyn . i '312 83*120! 5-840 0-980 1-870: 5*890 2-300 71-30 Rock Vawr . '290 77-980 4*390 0*570 0-960 8-550 7-550 62-50 The specific gravity both of cannel and bituminous coals averages about 1-270, distilled water at 62 Fahr. being rooo. The proportion of ash in the best class of bituminous coals averages 2-5, and in the residual coke 375 per cent. In cannel, the proportion of ash is much greater. The colour of the ash varies, according to the nature of its constituents, from white, through all the gradations of grey, cream, fawn, yellow, pink, red, to deep red and brown. The following is an analysis of the ash of a good Newcastle coal : Silica ...... 59*56 per cent. Alumina . . . . . 12-19 Peroxide of iron .... 15*96 ,, Lime ...... 9*99 Magnesia . . . . 1-13 Potash . . . . 1-17 100*00 The proportion of sulphur in fourteen samples of cannel averaged 1-21, and in forty-two samples of bituminous coal 1*312 per cent. COAL DEPOSITS 15 In the same samples the volatile matter and coke were as follows : Volatile Matter. Residual Coke. Cannel . . 44 71 per cent. . 55 -29 per cent. Bituminous coal 3472 . 65-28 Everyday experience shows that variations occur in the quality of the coal obtained from the same seam and in the same locality. The identical seam of coal also varies in quality in different districts. Coal got from those parts of the bed where the seam is thickest is more likely to possess uniformity of structure than that got near to the circumference of the basin. Mr. E. W. Binney's observations led him to the conclusion that seams of coal are materially affected by the nature of the super- imposed strata. If this is of an open character, such as sandstone, the gaseous matter can readily escape. On the other hand, if the roof is of almost air-tight black shale or blue blind, the gas is retained. Further, it is not unreasonable to infer that the vegetable matter of which coal is composed would be deposited irregularly. For example, during the ages of primeval vegetable growth, a larger proportion of leaves would be deposited in some places than in others where the deposits of bark and cellular tissue would be in excess. These conditions would naturally tend to produce variations in quality. In seams of cannel there is more uniformity of quality than in those of ordinary coal, due to the circumstance, as is supposed, of their having been formed from vegetable matter long macerated in water, thus insuring a more intimate admixture of the vegetable substances. It is well known that variations in the gas-producing qualities of coal are caused by the material having been stacked for a length of time on the pit bank. It is important that the coal which is to undergo distillation should be clean and dry. When coal in a wet or moist condition is placed in the retorts, the results are unsatisfactory in several respects. In the first place, the temperature of the retorts is reduced, and, as a consequence, extra fuel is consumed in restoring the temperature and in drying the coal by evaporating the moisture, 16 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS and driving it off as steam, before the coal is in a fit condition to undergo destructive distillation. Again a portion of the moisture or steam is decomposed in contact with the sulphide of iron (FeS), produced by decomposition from the disulphide of iron (FeS 2 ), or iron pyrites contained in the coal. The oxygen combines with the iron, forming the oxide of that metal, and the hydrogen with the sulphur, producing sulphuretted hydrogen. Carbon disulphide (CS 2 ) and other sulphur compounds are also formed in considerable volume. In this way the whole of the sulphur present in the coal is caused to pass off into the gas, and has to be subsequently removed in the process of purification, thus increasing the cost of manu- facture. On the other hand, when the coal is distilled in a dry condition, rather more than one-half of the sulphur present is left behind in the residual coke. Sulphur exists in cannel in the free state,, and in bituminous coals chiefly in combination with iron, as pyrites or disulphide of iron (FeS 2 ), and this in the retort is converted into the sulphide (FeS), or sesquisulphide (Fe 2 S 3 ), or both. The Storage of Coal. In gas making it is economical to use the coal as fresh as possible from the pit ; but, to be prepared for emergencies, the covered storage room for coal and cannel should be of capacity sufficient to contain from six to eight weeks' stock of the material, reckoned on the basis of the heaviest day's consumption. An exception to this rule may be made in the case of gas-works situated in the immediate vicinity of the coal fields from which the supply is derived. Under such circumstances, provision for two or three weeks' stock is ample. In storing coal, 43 cub. ft. of space per ton is required. All kinds of coal suffer deterioration by exposure to the weather, both as regards their heating, coking, and gas-yielding qualities. When coal is so exposed, being stored in the open air without any protecting covering, it is not only liable to be wetted by rain on its outer surface, but it also absorbs and retains moisture within its structural interstices. The effect of this excess of moisture is to cause disintegration, reducing the size of the lumps, and converting them to a consider- able extent into dust and coom. SOME RECENT ANALYSES OF COALS cooolninoooinin^i m o CM O >n i CM r-l t-x CM OO O O CO O i "o "o "o c> '<-> Vj- "on "m CJ tx - o\ <* tx co oo co CM tx ix co CM co a\ * .Q g tn tx _* p csi _m j>, p po p p vo TT oo po p r-i jn in co CM rx co oo x po p -! CM p CM vn ^- oo ' L, "o o o 'CM o Vi "CM 'CM "o o "CM "CM "r-i o o "<-i o CM o "1-1 o "o o '*-* "o "<-< o 'o '1-1 o "i-i '-< o O u O 55 W (^ 5 >;! ^ Q H ^ Z H w > u tx * CM 1 po pop p\ CM m en tx co tx co p >n co eft oo u-. co K vo '*-< bo bi 'I-H "r-< vo o CTi tx In 'm bo " ti o en c c rt "3 >> . 3 I 3;S "C 3 O (3 'S S '^ I ' "i ' "3-sl "S ^h ^ o S o - -1 . . . o jzaslsl '' iSwS^-sc 1 111 rt rt v jj Q "CQt^- oo o^^S^^ 'S'o *S 2 "! : : " : S? T^ J2^5J2 a a o c^ ' PQCQ(L) b O K K i-J 2 C PQCQ M " tn 5o ^ : . jl : , S >, , a-. 1 8 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS The exposure of the coal in the winter season in this climate is, of course, the most objectionable as regards disintegration. In hot climates the intense heat of the sun produces the disinte- gration. The ill-effects of this absorption of moisture do not end there. Oxidation of the particles of the coal also ensues ; and as this is only another name for eremacausis or slow burning, the material is not only reduced in weight, but its gas-producing power, both as to quantity and quality, and its coking qualities, are greatly impaired. An absolute loss of weight, due to the evaporation or slow combustion of the more volatile constituents, is also experienced. This is particularly the case with bituminous or caking coal ; cannel suffers next in degree, and anthracite the least. Varren- trapp found in one instance that coal which had been exposed for some years to the weather had diminished in weight to the extent of 38*03 per cent. Wet or damp coal not only yields less gas, but gas of an inferior quality. The sulphur impurities given off from it are more, thus augmenting the cost of purification ; whilst some of the sulphur compounds notably carbon bisulphide are not removable except by a greatly increased area of purification beyond what is to be found in most gas-works. Spontaneous Ignition of Coal. Coal containing a large proportion of iron pyrites (disulphide of iron), commonly called " brasses," when stored in a compact mass in a wet or humid state, is liable to spontaneous ignition. This is not an unusual occurrence in the experience of the gas manager. The indications that combustion has begun are a sensible rise in the temperature of the coal store, a sickly odour, and a choking or smothering sensation in drawing breath. There is this liability to spontaneous ignition in almost all bitu- minous coals of a friable nature. It is due to more than a single cause. It may arise from the condensation of oxygen within the pores of the carbonaceous particles, just as oily cotton -waste will fire spontaneously in the same way, by the rapid absorption of oxygen. According to Professor Abel and Dr. Percy, water or moisture does not accelerate, but rather retards, spontaneous ignition under these circumstances. The danger of firing is greatest with those coals which contain GASES OCCLUDED IN COAL 19 a large proportion of iron pyrites in the shape of nodules, or " brasses," as they are called, and which are stored in a deep mass in the wet condition. These " brasses " become oxidized by the atmospheric oxygen dissolved in the water with which the coal is saturated ; and the heat thus generated raises the temperature of the coal to ignition point. Notwithstanding a conflict of opinion on the subject, we believe that the best remedy for this is ventilation. Various expedients are resorted to for effecting this object, amongst which may be mentioned the insertion in the mass of coal of perforated iron pipes with the ends exposed ; coarse wickerwork baskets, without bottoms, are used with good results; and ven- tilating shafts of brick, or venetianed shafts of wood, both hori- zontal and vertical, have proved efficient. Unless the ventilation is thorough, however, the admission of air will do more harm than good, as a sluggish current will not reduce the temperature, but rather tend to develop and increase it. A thermometer let down through the pipes or shafts will indi- cate any rise of temperature, and iron rods thrust into the mass of 'coal, when withdrawn and touched by the hand will answer the like purpose. When the pyrites is present to a serious extent, the coal should be hand-picked, either at the colliery or when discharging at the gas-works. It is only sheer necessity, however, that will justify the employment of coal of this character for gas-making purposes. The Gases Occluded in Coal. Besides the liability to spon- taneous combustion or ignition, there is another strong reason why coal should not be stored in the open air, nor indeed under cover, for a longer time than is absolutely necessary. In all bituminous coals a constant chemical change is in pro- gress, by which gas is being liberated. This gas, though frequently several times the volume of the coal, is condensed within the solid substance, being occluded or enclosed therein, until by diffusion it escapes into the air, and to such extent the coal is depreciated for gas making. In warm weather and in hot climates this deterioration proceeds more rapidly than in low temperatures. Dr. Lyon Playfair and others in this country, and Dr. E. von Meyer in Germany, have investigated the subject, and the sub- joined table by the latter shows the quantity and composition of C 2 20 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS the gas so occluded, obtained from freshly raised samples of coal submitted to him for analysis. The plan adopted was to place 100 grammes of the coal in hot de-aerated water, which was then boiled as long as any gas con- tinued to be given off, and the gas collected was analysed by Bunsen's methods. Samples of Coal Submitted. No. i. Low Main Seam, Bewick Colliery, Newcastle 2. Maudlin Seam ,, 3. Main Coal Seam, Urpeth Colliery 4. Five-fourth Seam ,, 5- Wingate Grange Colliery, Durham 6. Low Main Seam 7. Harvey Seam 8. Fathoms from Surface. 30 74 108 . 148 Emily Vil, Woodhouse Close Colliery . 25 ANALYSIS. PERCENTAGE COMPOSITION OF THE GAS. Cubic Coal as above. CO, CH 4 Marsh Gas. N Centimetres of Gas from 100 Grammes of Coal. No. i ... 5-55 6-52 2-28 85*65 25-2 * 2 8'54 26-54 2-95 61-97 3'7 3 20-86 4-83 74" 3 1 27-4 4 16-51 Trace 5-65 77-84 2 4'4 5 o-34 85-80 Trace 13-86 91-2 6 I'I5 84-04 0*19 14-62 238-0 , 7 0-23 89-61 o-55 9*61 2II'2 , 8 5-3i 50-01 0-63 44'5 84-0 i cubic centimetre = 0-061028 cubic inch, i gramme = 0-0022 Ib. avoirdupois, 100 = 0-22 Ib. The Testing of Coal for its Producing Qualities. It is almost impossible to judge from the appearance of a coal whether its gas and coke yielding qualities are good, bad, or indifferent. So far as outward indications go, nothing is so deceptive to the inex- perienced in such matters ; and even to those who have had large TESTING OF COAL 21 practice in coal-testing, it is very difficult to forecast with an certainty the result of a trial of any particular sample. The most favourable signs are when the coal exhibits traces of calcium carbonate and charcoal deposits on the surfaces exposed by fracture, and the appearance of a brownish -coloured streak on being scored with a hard, blunt point. This latter is an invariable sign of richness. Some of the poorest coals and cannels have a fatty, unctuous appearance, suggestive of richness in gaseous properties. Again, the most valuable cannels and shales, yielding gas in extraordinary abundance, have a dull earthy cast, which might readily be taken as indicating poverty of composition and yield. The rich Boghead (Scotland), Sydney (New South Wales), Clover port (Kentucky) cannels or shales, and the new Abram cannel, Wigan, are striking examples of this latter kind. On the other hand, this does not hold good of the Brazilian shales or " Turba." These have a dull, clayey appearance, and are very indifferent both in the yield and in the illuminating power of their gas. The importance of being able ,to test samples of coal or cannel, before entering into a contract for the material in bulk, is therefore obvious. A test may be made either on a working scale or in the experi- mental apparatus in the gas manager's laboratory. In the former case several tons of the material have to be used, and the trial of a single sample is a formidable and tedious process, extending over many days, until the old gas in the apparatus and holder has been replaced by the new. It is obviously impossible to test a variety of samples in this manner within a reasonable period. Besides, such a method of testing is not always satisfactory. The manager has to take a good deal for granted ; he is largely depen- dent on subordinates for the attention and care that ought to be exercised, because his constant personal supervision throughout the time occupied by the test is out of the question . The experimental test is to be preferred for many reasons. The small apparatus is more under the command of the operator. Full justice is done to the material. The best results it is possible to obtain are secured. Time is economized in making the tests, because a number of samples can be tried in the course of, say, ten to fourteen days. It may be urged against the experimental, or laboratory, test, that, in practical working, equal results are unattainable. If this 22 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS be the fact, it only proves that either the practical working is at fault to the extent of the difference in result, or that the bulk of the material is not equal to the sample tested. Assuming, however, that the sample is a fair average of the whole, whatever the deficiencies of practical working may be, the coal at least should not be depreciated below its intrinsic value through defective heats and other faulty methods of carboniza- tion ; and although the actual everyday working of the material may afterwards fall short of the results obtained in the trial apparatus, these latter are a standard at which to aim. As a general rule, the difference between the results of actual use and the experimental results, with efficient plant and careful supervision, will not exceed seven to ten per cent, in favour of the experimental test. To argue that the quality of a coal should be judged and deter- mined solely by the results yielded in actual working, is just about as reasonable as to say that the illuminating power of gas should be decided by the methods of consumption through possibly defective fittings, and some of the burners in use by consumers. Whether coal or gas, the means best calculated to develop its intrinsic qualities should be adopted. Care should be taken to obtain a fair sample of the coal to be operated upon . For that purpose a full section of the seam should be obtained. It should then be broken up into small pieces and thoroughly intermixed, and from this, three several charges should be taken without selection. The charge employed in the laboratory trial is the zoooth part of a ton viz., 2-24, say 2j, Ibs. The following are the details of the testing apparatus (Fig. i) : RETORT. Cast iron ; Q-shaped ; 5 in. wide, 4 J in. high inside ; 2 ft. 3 in. long outside ; J in. metal. ASCENSION PIPE. 2 in. wrought tube. CONNECTIONS. i \ in. wrought tube. CONDENSER. 12 vertical ijin. wrought tubes, 3 ft. 6 in. long each. WASHER. i ft. long, 6 in. wide, 6 in. deep. PURIFIER. i ft. 2 in. square, 12 in. deep, with two trays of lime. GASHOLDER. Capacity, 12 cubic feet, with graduated scale attached. TESTING OF COAL The retort should be got up to, and maintained throughout the charge at, a bright red heat. If from any cause the temperature is much reduced, the test will not be satisfactory. This is especially the case in testing cannel and the rich shales. The time required to work off the charge of 2\ Ibs. will range from about twenty to forty minutes, according to the character of the coal. FIG. i. The illuminating power of the gas given out from each charge should be ascertained by the Standard photometer, no other being sufficiently trustworthy for that purpose. The average of the three tests is then taken, both for yield of gas and coke, and for the illuminating power of the gas, and this fairly represents the capabilities of the coal. The further conditions to be observed are that the holder be entirely emptied of air, or of the previous charge of gas, and that the condenser be drained of its contents. The test charge may be continued until the whole of the gas is expelled, or otherwise, depending on circumstances. In comparing two coals, an equal production from both may be obtained, and the comparative illuminating power then ascertained. The coke and breeze should be carefully drawn from the retort into a water-tight receptacle made of sheet -iron, closed by a lid. This is then placed in a bucket or other vessel of cold water, and, when sufficiently cooled, the contents are taken out and weighed. 24 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS For ascertaining the quantity of tar and ammoniacal liquor produced, drain the yield of the three charges from the condenser and washer, and measure this in a graduated liquid measure. The number of fluid minims in a gallon is 76,800. Thus: 60 fluid minims . 8 drams 20 ounces . 8 pints Then: Ibs. Ibs. per ton. As 675 (the weight of : 2240 : : the three charges of coal) = I dram. = i ounce. = I pint. = I gallon, The number of : The total minims minims of tar of tar and liquor and liquor ob- per ton of coal, tained And this -f- 76,800 gives the gallons of tar and liquor yielded per ton. Specific Gravity of Coal. To determine the specific gravity of the coal, take a small piece, suspend it by means of a horsehair from the under side of the pan of a carefully adjusted balance FIG. 2. (Fig. 2), and weigh it both in and out of water (fresh distilled) ; divide its weight in the air by the loss of weight in the water, and the quotient is the specific gravity. TESTING OF COAL 25 EXAMPLE. A piece of coal weighs, say . . 260 grammes. Loss of weight when weighed in water 204 ,, Then - 1*274 specific gravity of the coal compared 2O 4 with water as i-ooo. Note. Specific gravity is the relative weight of equal bulks of different substances, distilled water at 62 Fahr. being taken as the standard of comparison. At this temperature a cubic foot of water weighs 1000 ounces avoirdupois. Hence, the specific gravity of a body is also its weight in ounces avoirdupois per cubic foot. So that, knowing the specific gravity, the weight of any quantity of matter may be calculated by simple measurement. For example : In the instance just given, the specific gravity is shown to be 1*274 ; the weight of the coal per cubic foot is, therefore, 1274 oz., or 79*62 Ibs. avoirdupois. Calorific Values of Coal and Coke. To ascertain the calorific values of coal and coke, a number of calorimeters have been .designed, notably the Lewis Thompson, the Bryan Donkin, Wild's, and the Bomb designed by Berthelot and Mahler and modified by Dr. Kroeker. In testing a coal for its heating value, it is essential that a full section of the seam should be taken. In the case of coke, any quantity, but not less than a hundred- weight, may be taken for sampling purposes. The coal or coke, as the case may be, is broken up and spread out in a layer of any depth. It is then divided in two ; and one of the halves is taken and further broken up into smaller pieces. This is then divided into four quarters, and one quarter is taken and ground to fine powder. The fuel is then ready for testing. The method of procedure now depends upon the type of calori- meter used. The main principle, however, is, that the fuel is ignited in a vessel immersed in a measured quantity of water of which the temperature is known. The temperature of the water, after igni- tion of the fuel, is then taken until the maximum temperature is reached. The difference between the maximum and the minimum multiplied by the value of the calorimeter in water (which latter is supplied with each make of calorimeter) is the value of the fuel in calories. This latter is converted into British thermal units by multiplying by 3*97. 26 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Ash In Coal and Coke. To determine the quantity of ash in a coal or coke, a portion of the fuel is finely ground in a crushing machine or in a mortar. A portion, preferably 10 grammes, is accurately weighed in a platinum crucible, and heated in a mufHe furnace, until the fixed carbon is completely burned off. The residue is the proportion of ash in the quantity of fuel taken, and from this data the percentage is calculated. EXAMPLE. Weight of crucible, say 50 grammes and coke, say . . .60 of coke . . . . . . .10 of residue, sayT. . . . 0*5 .-. If 10 grammes of coal contain 0*5 of ash, what will TOO grammes contain ? 0-5 X ioo = 5 grammes, or 5 per cent. Coal Distillation. Coal is a complex organic compound, and, like all organic substances, the action of heat upon it is to resolve it into its elementary constituents, the chief being carbon, hydrogen, oxygen, and nitrogen. But there are many stages to be passed through before this final result is attained. It may be said that each degree of temperature in the distilla- tion of coal has its own products of decomposition, and each degree of rise in temperature produces a further breaking-up and rearrange- ment of the compounds whiph previously existed. From this it will be gathered that the products from coal distilled at a lowiemperature, say, 800 Fahr., will consist chiefly of members of the paraffin series along with defines. The lower members of these series are liquid, and the higher ones solid, so that coal dis- tilled at a low temperature will yield comparatively little permanent gas. As the distillation temperature is increased, the paraffin and hydrocarbons are destroyed, and benzenoid hydrocarbons, free carbon, and an increased production of permanent gas formed. The usual temperature attained in actual practice is from 1800 to 2000 Fahr., at which temperature there is a maximum yield of benzene, toluene, phenol, etc., in the tar, with a maximum of illuminating power in the gas. COAL DISTILLATION 27 Should the temperature be taken beyond this, there will be a larger production of gas, at the expense of its light-giving con- stituents. The tar also that is produced at a very high tempera- ture contains a large percentage of naphthalene, phenanthrene, pyrene, etc., at the expense of the much more valuable benzene, etc. The final stage of distillation, in which coal is split up into its elementary constituents, cannot be reached in practice, and of course is not desired, at any rate from a gas maker's point of view. As has been said, the tar produced at different temperatures varies greatly both in composition and appearance, but the study of tar comes more under the province of the tar distiller than of the gas manufacturer. Nuts and Slack or Dross, whether of coal or cannel, require very high temperature for carbonization. When the heat is not high they cake together in a mass, and at the end of the charge are drawn from the retort in a comparatively unspent condition. A table by Dr. Henry exhibits the qualities of gas at different periods of distillation From Half -a- Ton of Wigan Cannel. Time from 100 Measures 100 Measures of of Impure Gas Purified Gas contain consist of 100 Measures of Purified Gas ~* - Beginning of Distillation. | Other Sulphu- 1 Corn- retted ; pounds of Olefiant Hydro- Nitrogen Gas. ; gen. and Hy- Other Inferior Gases. Nitrogen. Consume Oxygen. Give Carbonic Acid. drogen. an hour i 5l \ 16 64 20 180 94 i hour 3 hours I, i 11 18 15 tf 5 1 210 200 112 108 5 2? . 13 15 176 94 7 , 2 2- 9 76 15 170 83 9 , i 2 J 8 77 15 150 73 10 , 2 6 74 20 120 54 12 1 ^ 4 76 20 82 36 From Half -a- Ton of Common Wigan Gas Coal. i hour 3 3 10 90 164 91 3 hours 2 2 9 1 68 93 5 7 3 2 I 3 6 5 lo 15 132 120 70 64 9 , I .2 2 89 9 112 60 ii I I 85 15 9 43 28 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS The rate of production of gas from 2 cwt. of Wigan coal in an experimental retort was found to be as follows : J hour . . . . 275 cubic feet. 1 245 ij hours . . . 200 ,, 2 .... 140 2i . 80 3 40 3i - 20 4 . . 15 Total v ...-.-,. 1015 cubic feet. The annexed table, by Miller, exhibits the quantity and specific gravity of the gas obtained from two bushels of coal during each of five hours' heating in an ordinary retort, and shows the impor- tance of restricting the time during which the coal is subjected to the action of heat in the manufacture of gas. The rich hydro- carbons diminished, and carbon monoxide and hydrogen increased in quantity as the experiment progressed. Cubic Feet. Specific Gravity. In the ist hour . . . . . 345 0-677 2nd . .203 0-419 3rd . . 118 0-400 ' 4th 54 0-322 5th . .20 With cannel the carbonization takes place in less time than with ordinary coal. For roughly estimating the weight of coal or cannel required to produce a given quantity of gas RULE. Strike off the last four figures from the quantity of gas produced, and the figures remaining will represent the coal or cannel in tons. Thus : 20 | 0,000 cub. ft. of gas = 20 tons coal. This will be evident, if we assume that a ton of coal or cannel produces 10,000 cub. ft. of gas. Should, however, the production rise above or fall below this standard, one-tenth of the coal must be COAL DISTILLATION 29 deducted for every 1000 cub. ft. rise, and one-tenth added for every 1000 cub. ft. fall, in the production. The average weight of coal per cubic yard is Anthracite, per cubic yard, solid . . 2160 Ibs. Bituminous ,, ,, . 2133 Cannel ,, . . 2160 Coal, stored in the usual way, per cubic yard . . , I 4 Coke, per cubic yard . . ... 670 Breeze ,,.... . 950 ,, The average percentage yield, by weight, of good bituminous coal is as follows : Gas , . ... . . . 22 per cent. Coke and breeze . . . . . 64 Tar ....... 5 >, Ammoniacal liquor . . . . 9 100 In order to find the value of gas in grains of sperm per cubic foot from the given illuminating power RULE. Multiply 120 (the grains allowed per hour for the con- sumption of the standard sperm candle) by the illuminating power, and divide by 5 (consumption of gas in cubic feet per hour by the standard burner). The answer will be the value of the gas in grains of sperm per cubic foot. EXAMPLE. What is the value of gas in grains of sperm per cubic foot, the illuminating power of which is 19*46 candles ? 19-46 x 120 _ = 467 grams of sperm, value. To find the value of any coal per ton in pounds of sperm, the yield of gas and illuminating power being known RULE i. Multiply the cubic feet produced per ton by the value of the gas in grains of sperm per cubic foot (ascertained by the previous rule), and divide by 7000 (the number of grains in i Ib. avoirdupois). The answer will be the value of the coal in Ibs. of sperm per ton. EXAMPLE. What is the value of a certain coal in Ibs. of sperm 30 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS per ton, whose yield of gas is 10,540 cub. ft., and illuminating power 19*63 standard sperm candles ? 10/63 X 120 , ,, . . , , . - = 471-12, value of the gas in grains of sperm per cubic c/ foot. Then = 70Q/37 Ibs. of sperm per ton, value. * 7000 Or by RULE 2. Divide the yield per ton by 5 (cubic feet of gas con- sumed per hour by standard burner) ; multiply by the ascertained illuminating power and by 120 (consumption of standard sperm candle per hour in grains) ; lastly, divide by 7000 (number of grains in I Ib. avoirdupois). The answer will be the value of the coal in Ibs. of sperm per ton. EXAMPLE. What is the value of a certain coal in Ibs. of sperm per ton, whose yield of gas is 10,540 cub. ft., and illuminating power 19-63 standard sperm candles ? Then 10,540 - = 2^o821I63XJ2a = 709-37 Ibs. of sperm per ton, value. 7OOO To ascertain the relative value of different coals and cannels, attach approximate or actual market prices to the sperm pounds as ascertained above, and to the several residual products, cast up the various items, and compare them by the ordinary rule of proportion. EXAMPLE. The two coals to be compared are No. i, yielding s. d. 10,600 cub. ft. of gas per ton, 17 \ candles value = 636 Ibs. sperm at d. i 6 6 13^ cwt. coke at sd. 057^ 10 gals, tar at ijd. o i o 22 gals, ammoniacal liquor at id. o i 10 i 15 o No. 2, yielding s. d. 9700 cub. ft. of gas per ton, i6f candles value = 557 Ibs. sperm at |d. 14 cwt. coke at sd. 9 gals, tar at ijd. 20 gals, ammoniacal liquor at id. RELATIVE VALUE OF DIFFERENT COALS 31 Assuming that No. i is I2s. 6d. per ton, the relative value of No. 2 will be found as follows : As i. 155. od. : i. us. 7fd. : : I2s. 6d. : us. 3^d. value per ton of No. 2. Farmer's rule to find the relation between quantity of gas per ton and illuminating power may be quoted here, but it must not be assumed as absolutely correct. It is only approximately so, and that only within a limited range. If a given coal yields a known volume of gas of a known illuminating value, to ascertain how much gas it will yield of another value RULE. Multiply yield of gas by the illuminating power, divide by the required power, and the quotient is the quantity. EXAMPLE. A coal yields 10,600 cub. ft. per ton of i6-candle gas ; how much will it yield of 14 and 17 candle gas respectively ? 10,600 X 16 = 169,600. Then 169,600 . 169,600 - = 12,114 cub. ft. and - - = 9976 cub. ft. 14 17 The above presupposes that the period of distillation is 'extended or abridged, as the case may be. GAS PRODUCTION. Carbonization. This, the first process in gas making, is also the most important. Any want of economy here (and the word " economy " implies efficient apparatus, proper conditions of working, and good management generally) cannot be compensated for in any of the subsequent stages or processes to which the gas has to be subjected, or through which it has to pass before it reaches the consumer. The carbonization or destructive distillation of coal for the production of gas is accomplished in hermetically sealed vessels known as retorts. In the earliest days of gas manufacture, the retorts, which were of cast iron, were placed or arranged in the vertical, the inclined, and the horizontal position. Retorts placed in the vertical position were the first to be tried. These proved objectionable by reason of the coal consolidating in a mass, thus preventing the free exit of the gas and making it a matter of difficulty to remove the resultant coke. Another 32 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS objection was the impossibility of carbonizing the comparatively large bulk of coal hi anything approaching a uniform manner. Modern skill and ingenuity, however, have succeeded in over- coming the early difficulties which confronted the practical use of retorts set in the vertical position ; and the carbonization of coal in such retorts is now an accomplished fact. Retorts set in an inclined or horizontal position were an important advance on the early retorts as set vertically, and were so considered by gas engineers. But when we say that retorts were set in an inclined position, it must not be presumed that they were set on the scientific principle of the present-day " inclined re- torts." They were set at any angle between the vertical and horizontal, though generally at a smaller angle than that at which inclined retorts are now set, and various devices were arranged whereby the coal was assisted mechanically through the retort. But with lack of proper coal-handling machinery, and through other causes equally adverse to success, retorts set at an angle were dis- carded in favour of those set horizontally, until a comparatively recent date, when M. Coze, of Rheims, set inclined retorts on the principle of the angle of repose of coal viz. about 32 degrees. FIG. 3. Retort House. The retort house may be designed for a single or double stack of retorts on either the horizontal or inclined system, and may be of the ground-floor or stage-floor type of erection. RETORT HOUSES 33 FIG. 3A. FIG. 4. 34 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS For retorts set horizontally the ground floor house (Figs. 3, 3A, and 4) is the most usual form. In .this the charging and drawing of the retorts are conducted on the ground level. Now that generator furnaces for heating the retorts under the generative and regenerative systems arepargely used, owing to their proved efficiency, provision is made for them in houses of this class by carrying the foundation of the retort stack to a depth of from 9 ft. to 10 ft. below the ground floor line, an underground passage about 8 ft. or 9 ft. wide being formed on each side of the stack if it is a double one, or in front if single, for access to the furnaces and flues. (See Figs. 3, 3A, and 4.) The stage floor house proper (Figs. 5 and 6) has not only a ground floor, but a stage floor at an elevation of 10 ft. or 12 ft. above the other. From this latter the retorts are charged and drawn, the hot coke being discharged through suitable openings in the stage floor (see Figs. 7, 8, and 21), when it is slaked and wheeled or otherwise conveyed away into the coke yard. RETORT HOUSES 35 A house of this description costs more than a ground floor house ; but, in large works especially, it can be operated with more economy, and the advantages it offers for the removal of the coke, the application of the generative and regenerative systems, and in other ways, are very great. The clear space in front of a stack with horizontal retorts should not be less than 18 ft. When it is intended to employ machinery for charging and drawing the retorts, 22 ft. is required. For convenience in hand charging and drawing, a slight inclination say, 6 in. to 9 in. in the whole width towards the stack, should be given to the floor. This allows the waste water to drain away, and is also handier for the stokers in charging. The height of the walls from the charging stage is generally from 28 ft. to 32 ft., the latter dimension being necessary where charging and drawing machinery is to be used. A house designed to contain retorts on the inclined system, whether for a single stack or for a double stack, either face to face, as in Fig. 7, or back to back, as in Fig. 8, differs materially from a house containing horizontal retorts. The house is necessarily higher, and the dimensions in front and behind the stack require modifying considerably under the new conditions of working. As to whether, in the case of a double stack of retorts, they D 2 36 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS should be set face to face (Fig. 7) or back to back (Fig. 8) is a matter of opinion. We much prefer Fig. 7, as admitting of better venti- lation on the higher operating floor. On this floor, with back to back retorts the heat is often unbearable. The following may be taken as convenient sizes : House for a single stack of horizontal retorts. Width inside, 32 ft. Heightrfrom charging floor to springing of roof, 21 ft. FIG. 7. House for a double stack of horizontal retorts. Width inside, 60 ft. Height from charging floor to springing of roof, 28 ft. Height from oasement to springing of roof, 38 ft. House for two stacks of 20 ft. inclined retorts, set face to face. Width inside, 99 ft. or 100 ft, above the set off. Height from basement floor to charging roof 22 ft. 6 in. Height from charging floor to springing of roof, 31 ft. 6 in. Height from basement floor to drawing floor, 10 ft. Width of stack, 17 ft. Width of charging stage, 18 ft. Width of drawing stage between stacks, 30 ft. ROOFS. The retort house roof should be constructed of either wrought-iron or steel, and slated. The design of the roof will, of RETORT HOUSES 37 course, vary with the width. For houses up to 60 ft. wide some form of king post roof is generally adopted. Above this width and this applies to inclined retort houses the roof may be either elliptical, semicircular, or, as in Fig. 7, divided into two ; the valley end of principals being carried by a girder extending the length of the house. Corrugated-iron sheeting may be used to cover the principals t / FIG. 8. in the place of slates, and, being much lighter than slates, the principals may be lighter in construction and farther apart, so reducing their number. The first cost of a roof of this descrip- tion is less, but its durability is inferior to a slated roof. The sheets should not be thinner than No. 20 gauge. Ventilation. Suitable openings should be left in the walls of the retort house at a height slightly above the stack, for ihe admission of air and light. The ventilation should be good, and, with this object in view, louvres should extend from one end of 38 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS the roof to the other, and be of ample capacity. Ventilating tubes or towers are sometimes used alone, or in addition to the louvre ventilator. These are efficient, and present a good appearance. Retort Stack. This necessarily varies in size and general construction according to the system of heating adopted, and the number, dimensions, and general arrangement of retorts in the setting. In the smaller-sized works, where it is inconvenient to let down a faed of " throughs," the stack is better constructed for single retorts about 10 ft. long over all, and containing settings of threes, fives, sixes, or sevens, according to the size of the works. In larger works the double stack is preferable, as, in this, one furnace may be made to serve for the double or through setting, thereby minimizing the furnace fuel and labour account. It is rarely that retorts are set fewer than seven in a bed in large works, and even as many as twelve retorts are set in one bed, with an elevated travelling stage in front, from which the higher retorts are charged and drawn. Too much stress cannot be laid upon the necessity for a good, dry, and solid foundation for the retort stack and setting. Should the foundation be of a yielding nature, the setting will be liable to crack by uneven subsidence, thereby causing short-circuiting in the flues, as well as other evils. If the foundation be wet, the brickwork of the setting will absorb the moisture, and the heat from the furnace, whilst par- tially heating the retorts, will be largely wasted in volatilizing this water in the brickwork. To ensure a good foundation there should be a bed of concrete laid over the whole area the retort stack is to cover. The thick- ness of the concrete will, of course, depend to a large extent on the nature of the ground ; but in ordinary solid ground, and for direct fired retorts, the concrete should not be less than i ft. ; for generator and regenerator benches, ij ft. ; and for an inclined retort stack, 2j ft. thick. On this concrete bed the footings of the stack will be built, and a double layer of red bricks laid for the floor or setting foundation. The division walls or piers of the stack should not be less than 1 8 in. thick, and built of best fire-clay bricks, set in fine, well- tempered fire-clay. RETORT STACKS 39 With thinner walls there is considerable radiation when the setting next to the one working is let down ; whilst with walls of this thickness, each setting conserves within itself nearly all the heat generated in its furnace. The end or buttress walls should be from 2 ft. 3 in. to 3 ft. thick, according to circumstances the larger dimension preferred lined on the inside with 9 in. of fire-brick, and faced on the outside with the same ; the intervening space being built in ordinary red brickwork. The whole of the brickwork in a retort stack, whether fire- brick or otherwise, should be set in fire-clay, as ordinary mortar rapidly crumbles away when subjected to heat. The main arches for seven retorts, and under, to a setting, should be semicircular ; for a setting of more retorts than seven, the arch is generally either segmental or elliptical. The semicircular arch may be built in ordinary fire-brick rings, three half-rings deep. Elliptical and segmental arches, being weaker than the semicircular, require greater care in building. They are best built with a Q-in. ring of purpose-made slabs and a 4j-in. ring of arch bricks, carefully set in fire-clay with fine joints. A space of from 3 to 4 in. is sometimes left above the top of the fire-brick arch to allow for expansion. But the tendency is for the arch to sink, and to help to counteract this the floor of the bench is given a slight curvature upwards from the front and back to the centre. The top of the stack should be haunched up five courses of brickwork above the top of the arch, of good common bricks, faced with fire-bricks, laid solid, and finished with cornice or coping. In the case of an inclined stack, the haunching is stepped. To prevent undue radiation, the front wall of the oven should be a brick and a half, or 14 in., thick. Fig. 9 gives a good idea of the construction of a bench con- taining a setting of seven direct-fired retorts. Flues and Draught. The main flue for direct-fired furnaces is generally built along the top of the stack, and communicates with the setting by means of flue holes in the crown of the arch. These should be 12 in. square and provided with damper tiles, 27 in. long, 16 in. wide, 3 in. thick. With settings on the generator and regenerative systems, the main flue should be built at the back of the furnace and in the lower 40 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS portion of the stack. This ensures the heat from the waste gases being kept within the setting. For a double stack containing eight or ten ovens or benches on each side, the chimney being in the centre, the main flue should also be double, and the internal dimensions of each division not less than 36 in. in depth by 15 in. in width. For even a less number of ovens the size of flue should not vary greatly from the above. An insufficient draught, whilst it invariably results in FIG. 9. diminished heats, causes a waste of fuel, from the consequent incomplete combustion in the furnace and the usual hard firing that accompanies it. The flame which is occasionally seen at the top of a retort house chimney is significant of this defect. The flame is produced by the unconsumed carbon monoxide uniting with its due proportion of oxygen on coming in contact with the atmo- sphere, and, by combustion, being converted into carbon dioxide. When the proper quantity of air is supplied to the combustion chamber, the carbon monoxide produced is there converted into RETORT HOUSE CHIMNEYS carbon dioxide, and the heat thus generated is utilized for the distillation of the coal contained in the retorts. An excessive draught through the ovens is to be avoided, as well as an obstructed one. If too much air is drawn in, its effect is to reduce the heat, as well as to cause the consumption of an excess of fuel. Hence the importance of being able to control the draught by means of a damper placed at the entrance of the cross flue into the main flue of the bench. According to the experiments of Dulong i lb. of hydrogen, burning to water, yields 62,535 units of heat, i carbon, to carbonic acid, 12,906 i carbon, to carbonic oxide, ,, 2,495 i carbonic oxide, to carbonic acid, ,, 4.478 NOTE. The English standard unit of heat is the quantity of heat necessary to raise the temperature of a pound avoirdupois of water i Fahr. The French calorie is the quantity of heat required to raise the temperature of a kilo. (2*2 Ibs. avoir- dupois) of water i Cent. As a rule, when firing with coke, cleaning off the fire bars once in twelve hours is sufficient. Too frequent cleaning entails a waste of coke, besides reducing the heat of the oven. Instead of the tall chimney stalk at the end of the retort house, it is the custom to erect chimneys or shafts of less altitude imme- diately over the bench, or between the benches, rising a few feet above the roof, and serving for four or more double ovens on each side. These are found to produce a sufficient draught, they are more uniform and regular in their action, and their cost is neces- sarily less. But as they deliver the products of combustion into the atmosphere at a low level, their use should be restricted to neighbourhoods where the nuisance is unobjectionable. When the room can be spared, it is best to erect the chimney between, and apart from, the retort benches ; so that when the latter need to be taken down and rebuilt, the chimney, being a more permanent structure, remains undisturbed. Sometimes each bench is supplied with a small shaft for its own use. In some American gas-works the main flue and chimney are dispensed with altogether, the opening in the crown of the bench being found sufficient, it is said, to afford the requisite draught. Even assuming the draught, under such conditions, to be ample for ensuring perfect heating and carbonization, which may be doubted, the objections to allowing the hot fumes to 42 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS escape into the retort house underneath the roof are sufficiently obvious to cause the practice to be condemned. The following is a useful rule for determining the size of the vertical opening in retort house chimneys about 70 ft. in height : Allow i| sq. in. of area for each lineal foot of retort, or, say, 15 in. per mouthpiece. Example : Required the internal sectional area of a chimney stalk serving ten double benches of eight retorts, or sixteen mouthpieces each, five benches on each side of chimney ; retorts 20 ft. through ; total, 160 mouthpieces. Then 160x15 =2400 - = 16-66 sq. ft. area. 144 Retorts. The materials of which retorts, for the distillation or carbonization of coal, are made, are fire-clay and cast-iron: In the early days of gas-lighting, and for many years later, cast-iron retorts were used exclusively, but clay retorts, in the face of much prejudice and opposition at first, gradually advanced in popularity as their merits became known, until at the present time their adoption is almost universal. There were many reasons why iron retorts should give place to those of the more refractory clay. The iron retorts were incapable of withstanding a heat sufficiently high for the distillation of coal in the most economical manner ; the highest temperature at which it was advisable to work being 1830 Fahr., a bright cherry red. They were also liable to rapid oxidation, rendering necessary the frequent removal of the scale, if the proper temperature was to be maintained. Cast-iron retorts are now only employed in very small works, and in coal-testing plants, as here they possess an advantage over clay, in bearing letting down frequently without suffering damage. The round, 15-in. diameter, and the p -shaped, 15 in. by 13 in., are the handiest, and 7 ft. 6 in. is a convenient length. They are usually made if in. thick, with an ordinary flange to which the mouthpiece is attached. Their weight is 16 to 18 cwt. Iron retorts should always be scurf ed before being let down, otherwise the unequal contraction of the incrusted carbon and the metal of the retort in cooling will cause fracture. The duration of an iron retort is equal to the production of from 700,000 to 800,000 cub. ft. of gas. CLAY RETORTS 43 Clay Retorts. The chief advantages clay retorts possess over those of iron are, the higher temperature to which they may be subjected without collapse, with a consequent greater yield of gas per mouthpiece, and a longer life. Until within recent years hand-moulded retorts were chiefly hi use. Such retorts, however, are not of a uniform consistency throughout ; consequently, when they are heated, uneven expan- sion and contraction takes place, with the result that cracks appear. This want of consistency is no doubt due to the slow process of hand moulding, in which it is almost impossible to thoroughly work the material together. This fault has been overcome by the introduction of machinery in retort manufacture, in which the clay is subjected to great pressure. For inclined retorts, which are not parallel throughout FIGS. 10, n, 12, 13. their length, an expanding die is used. Besides its uniform con- sistency, it is further claimed for the machine-made retort that its surfaces are smoother, and therefore offer less attraction to the deposition of carbon. The usual section of the clay retort is either the round (Fig. 10), the elliptical (Fig. n), or the Q (Fig. 12), with a modification of the latter known as the dished Q (Fig. 13). Clay retorts are usually made 3 in. thick and parallel throughout their length. The front portion of the retort to which the mouth- piece is attached may be flanged or swelled 4 in. thick and 9 in. broad, and holed for the insertion of mouthpiece bolts ; or the retort may be 3 in. throughout its entire length and the mouthpiece socketed on to the retort. Of the two. methods of attachment we prefer the latter. " Single " retorts are usually made in one piece, with a stopped end. When the retorts are through, they are usually in three pieces, jointed together, and have a mouthpiece at each end. 44 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS The advantages.gained in using this kind of retort are important in some respects. The accumulation of carbon is less, owing to the absence of backs. The current of air which is drawn through their interior every time they are charged tends to loosen any carbon deposit that takes place. More heating surface for carbonization is obtained without additional expense, and that in the hottest part of the oven. They are also drawn with greater facility. The scoop (Fig. 51) is, in the absence of machinery, generally used in charging these retorts. As they have to be- drawn and charged at both ends simultaneously, they cannot, where the scoop is used, be conveniently worked where the stokers are fewer than six in number . With the use of through retorts, however, the gas has a tendency to travel up only one of the ascension pipes at a time, either owing to there being a greater seal in one of the hydraulics or by reason of one of the two ascension pipes being partly choked. Therefore, where the through retort is adopted, each ascension pipe should be made large enough to readily take the whole of the gas produced in the retort. Further, it is alleged against through retorts that with their use there is an increase in the percentage of sulphur compounds in the gas, and also that they have a tendency to produce naphthalene deposits. The following are useful and convenient sizes of clay retorts : Round . i6in.diam.\ Oval . . 21 X 15 in. / Inside measure, and 10 -ft. Q- shaped . 21 X 15 in. I long outside. Q . 22 X 16 in. ) The weight of a clay retort of the above sizes is from 14 to 17 cwt. For very small works, the following sizes are more suitable : Round ; ; V; 14 in. diam., measu and ft> Oval .18x14 i ong ou tside. Q -shaped . 18 X 14 J Retorts made of fire-bricks and tiles or blocks rebated or grooved and jointed with fire-clay are still preferred by some engineers (Fig. 14). In the matter of durability, they possess' a clear advantage over the moulded clay retort, their life being BRICK AND TILE RETORTS 45 three or four times that of the other ; and though their first cost is more, this is compensated for by the saving in wear and tear. Large retorts of this class, 30 to 50 in. wide, which at one time were common enough, are objectionable for many reasons. A large area is exposed to the cold air every time the charge is drawn, and the time occupied in drawing them is necessarily con- siderable. Again, there is a tend- ency to allow carbon to accumu- late in such retorts, because in the ample space the inconvenience of the presence of a thick body of carbon is not felt by the men in drawing and charging. If the re- | J |j- quired temperature, however, is kept up under these circumstances, FIG, 14, it must be at an excessive ex- penditure of fuel and labour. The greater depth, of the coal, and the constant inequality of carbonization between the inner and outer portions of the charge, are also serious drawbacks to their use. By reason of its shape, the round retort is the strongest and most durable, but it is not equal to the others as a carbonizer, and when it has been tried in inclined settings, it has not been a success, owing to the jamming of the coke in discharging. For inclined settings it has been found necessary to modify the usual sections of the retorts somewhat, so as to facilitate the discharging of the coke. It will be readily understood that the coke in an inclined retort is liable to jam during its progress downwards. To overcome this, the retort, usually Q - shaped, is made to taper from the bottom to the top, not less FIG x than 4 in. in the 20 ft. The modification (Fig. 15) of the Q retort, introduced by Mr. Herring, at Edinburgh, is the outcome of a study of this question. The usual sizes of the inclined Q retort are from 21 to 26 in. wide by 15 in. deep at the bottom, and from 18 to 22 in. wide by 15 in. deep at the top. The length of the inclined retorts varies from 15 to 20 ft. ; but it 46 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS will be recognized that the labour in filling and drawing a 2o-ft. retort is very little more than that for a 15-ft. retort. It has been found by experience that it is a mistake to taper the cast-iron mouthpieces of inclined retorts, as was at one time practised. The section of the retort should be continued right through the mouthpiece. In moderate-sized works, where coke firing is employed, each single horizontal retort should be of capacity sufficient to hold a charge of from 2f to 3 cwt. of coal ; and with five or six hours' charges the yield ] per mouthpiece with good bituminous coal should be] at the rate of 6500 to 7500 cub. ft. per diem of twenty-four hours. f*' Where heating by regenerative furnaces is adopted, the charges may be heavier or more frequent ; and the twenty-four hours' yield per mouthpiece will range from 7000 to 9000 cub. ft., according to the quality of coal used. Even this yield is exceeded where the retorts are heated and worked under the best conditions. Now, eighteen months' continuous production at the rate of, say, only 7000 cub. ft. per mouthpiece per day, is equal to a total production of over 3| million cub. ft. of gas. The duration of clay retorts greatly depends on the setting. When the retorts are properly supported, and suitably protected from a cutting heat from the furnace, they will last for two or three years ; otherwise and this is nearer their average life they will be burnt out in fifteen to eighteen months. The system of completely or nearly filling the retorts, and the adoption of ten- and twelve-hour charges, materially increases the production per mouthpiece. Sufficient data has not, however, as yet been obtained as to the wisdom of this procedure. The system is one, however, -that holds out promise of being successful. It is an error to suppose that the brickwork in the walls supporting the retorts causes a diminution in the available heat. Take the case of two benches of retorts set, the one with as much brickwork as is required for proper support without obstructing the draught or unnecessarily covering the retort surfaces ; and the other having the least possible quantity of brickwork, supporting (say, for example) the retorts only at their extremities. In getting these benches in action for the first time, there can be no doubt the latter would be the first to attain the desired temperature ; but although the former would require a little longer time, and the RETORT SETTINGS 47 expenditure of more fuel at first, the superior regularity of its action over the other in distilling the gas from the coal will scarcely be questioned. No doubt the thinner the retorts themselves, compatible with strength, the better, so that the heat may the more readily pass to their interior. But the circumstances attending the retort as the vessel containing the material for distillation are not to be con- founded with those appertaining to the adjacent brickwork. This need not be more than is reasonable, but it is better to err on the side of excess than too little. Dimensions for Settings of Retorts on the Direct- Fired System. For three 18 in. by 14 in. ovals or Q 's, 9 ft. long : Width of oven, 5 ft. 2 in. ; height, 6 ft. 3 in. ; depth, git. 1 in. Width of furnace at grate bars, 9 in. Width of furnace at springing of arch, 16 in. Length of furnace, 30 in. Height from floor-level to underneath the flanges of the two bottom retorts, 2 ft. 3 in. Number of grate bars, two ; 30 in. long each, made of 2 in. square bar-iron. For five 21 in. by 15 in. ovals or Q 's, 10 ft. long : Width of oven, 8 ft. ; height, 7 ft. 6 in. ; depth, 10 ft. i in. Width of furnace at grate bars, 10 in. Width of furnace at springing of arch underneath the middle retort, 18 in. Length of furnace, 30 in. Height from floor-line to underneath the flanges of the bottom retorts, 2 ft. 8 in. Number of grate bars, two ; 30 in. long each, made of 2 in. square bar-iron. For seven 21 in. by 15 in. ovals or Q 's, 10 ft. long : Width of oven, 8 ft. 6 in. ; height, 8 ft. ; depth, 10 ft. i in. Width of furnace at grate bars, 12 in. Width of furnace at springing of arch, 20 in. Length of furnace, 36 in. Height from floor-line to underneath flanges of two bottom retorts, 16 in. Number of grate bars, three ; 36 in. long each, made of 2 in. square bar-iron. 48 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Vertical retorts in cross section may be circular, oval, elliptical, or rectilinear but with rounded ends, as experience may dictate as the best. The following are the respective sizes of the Dessau, Woodall- Duckham, and Glover-West retorts in some recent settings : Cross Section at Cross Section at Length Top of Retort. Bottom of Retort. over all. Dessau 9 in. X 22 in. 13^ in. X 27 in. 13 ft. Woodall-Duckham 46 J in. X 8 in. 63 in. X 20 in. ] 25 ft. Glover- West 27 in. X loj in. 33 in. X 18 in. 1 25 ft. But all these dimensions are subject to modification. Chamber Ovens. The carbonization of coal in chamber ovens is being extensively introduced abroad. Twenty-four hour charges of 8 to 10 tons of coal are adopted, and it is claimed that this system produces a larger yield of gas with a higher lighting and heating value than any other system at present in use ; also that the coke produced can be used for metallurgical purposes. The Heating of Retorts. There are in present practice two distinct systems whereby horizontal retorts are heated. The first system, known as the " direct fired/* is that in which solid fuel is burned to carbon dioxide by the admission of an un- regulated supply of air to the underside of the fire-bars, the retorts being heated by direct contact with the products of combustion. That this system is imperfect is well known, and it is only in the smallest works, or where water in the foundations and other diffi- culties are encountered, that it is adopted. On the other hand, a stage floor with the regenerator arrangements above ground might be adopted. The better system, that of gaseous firing, is one in which solid fuel is converted into combustible gases, these being conducted to the region where the heat is required,^and there mixed with sufficient air for their perfect combustion. From a practical as well as from a theoretical point of view, gaseous firing has everything to recommend it. The saving in fuel is considerable, even on the best results obtained by direct coke firing. Clinkering at the base of the retorts is avoided, and consequently wear and tear of the setting is reduced, the heats are higher and steadier, and heavier charges can be employed, increasing the production of gas per mouthpiece and economizing space in the retort house. GASEOUS FIRING 49 The application of gaseous firing has a much greater field than is provided by its use in gas-works, but the main feature of all gaseous firing is the " producer." There are many types of producer, notably those of Siemens and Liegel, but, though they vary in the details of construction, the principle of action in each is identical. As applied to use in gas-works, the producer is best contained within the arch of the retort bench, and the usual forms are as shown in Figs. 16 to 22. It is always advisable, where circumstances per- mit, to have a full depth producer, inasmuch as a deep bed of fuel gives the maximum efficiency. Its dimensions will, of course, depend upon the amount of work it has to do. A producer of a fuel capacity of about 75 cub. ft. and 6 to 7 feet in depth of fuel is sufficient for a setting of eight 20-ft. through retorts. The closed hearth pro- ducer, as shown in Fig. 17, has many points in its favour, both in regard to working efficiency and cost of maintenance ; but owing to difficulties in clirkering, the open hearth with ash-pan and fire-bars is more generally adopted. The producer is filled through the charging door at the top, a shoot being generally employed for this purpose, and the coke rests on the hearth (Fig. 17) or fire-bars (Fig. 19). The air necessary for combustion is admitted through nostrils or ports at the bottom of the producer, the openings in them being regulated by means of slides, so that the air admitted is under absolute control. The action in the producers is, that the air entering the furnace causes the combustion of the fuel, with carbon dioxide as the product. FIG. i 6, 50 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS The carbon dioxide then passes through the incandescent fuel in the higher portion of the producer, and is there converted into the combustible gas, carbon monoxide, according to the equation, CO 2 -f C = 2 CO. From this it will be readily seen that the size of the producer must be such, and the quantity of air admitted to it must be so governed, as to produce the maximum of carbon* monoxide at the top of the producer. Hence follows the rule that there should FIG. 17. always be a good depth of fuel within the producer, so that all the carbon dioxide formed may be converted into carbon monoxide. It is usual to have either a steam supply to the producer or a stream of water running on to drip-plates (Fig. 18), and from thence falling to the ash-pan, which should be kept full of water. The advantage of the steam or water supply to the producer is threefold. It disintegrates the clinker, keeps the fire-bars in good condition, and helps in the formation of the combustible gases from the producer. The steam entering the producer and meeting with the in- GAS PRODUCERS candescent fuel is split up into its constituents, hydrogen and oxygen. The oxygen assists in the combustion of the fuel, and the hydrogen passes on through the fuel, and adds to the volume of the combustible gases. But the use of steam is limited in application, owing to the large amount of heat absorbed from the furnace in its dissociation. This heat is rendered latent in the hydrogen, and evolved again in its combustion in the combustion chamber. Without the use of steam the temperature in the pro- ducer is about 2700 Fahr., but such a high tempera- ture is not necessary for the reduction of carbon dioxide into carbon monoxide, the minimum temperature re- quired being about 2200 Fahr. ; so that steam may be used to the extent neces- sary to keep down the tem- perature to this point, which is equal to about 18 parts of steam to 100 of carbon. The arrangement of one producer to a number of settings has been tried in several instances, but not with any permanent success so far. From the producer, the combustible gases pass to the combustion chamber, generally arranged beneath the bottom middle retort, where they meet with the air provided for their complete combustion. The difference between the two systems of applying gaseous firing, known as the generator (Fig. 17) and regenerative (Fig. 19) systems, arises with the question of the supply of air (" secondary air," as it is called, to distinguish it from the " primary air " admitted to the producer) to the combustion chamber. On the generator system the secondary air is provided in two ways. It either passes direct and in a cold condition to the FIG E 2 52 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS combustion chamber, or through channels arranged alongside the producer, thereby absorbing by conduction a certain quantity of heat from the producer before it reaches the combustion chamber. On the regenerative or recuperative system, the secondary air is heated by being made to traverse more or less tortuous pas- sages intersected by flues down which the waste gases are passing from the furnace to the chimney for further work ; the waste gases finally leaving the setting at a temperature of about 600 Fahr. FIG. 19. There are many forms of the regenerative part of the furnace in actual use, but they resolve themselves into two main types according as to whether the inventor considered that air takes up heat slowly or quickly. In one case we have long, tortuous passages for the secondary air to travel along before reaching the combustion chamber. In the other case the passages are short. The regulation of the primary and secondary air supplies depends upon the design of the setting, and no rute can be furnished that will be applicable to retort settings generally. The flue areas, and conditions of draught, are so varied that only by experience can the proper working be insured. REGENERATIVE SYSTEM OF FIRING 53 Semi-regenerators are sometimes adopted. In these a cavity of about 3 or 4 ft. in depth is made in the floor in front of the retort bench, being covered with cast-iron plates, and having a movable door or lid to give access underneath. We do not recommend them, as the workmen are subjected to an objectionable degree of heat in clinkering and removing the ashes. If there is one point which necessitates greater care and con- sideration in the construction of the retort setting than another, i FIG. 20. it is that with regard to the position and size of the combustion chamber. With the ordinary direct firing where the retorts are heated by conduction, it is necessary that the products of combustion impinge as much as possible on the surface of the retorts. With gaseous firing, however, such a policy is wrong. Here we have the combustible gases from the producer mixing with the secondary air at the combustion chamber, with ignition. The flame should not impinge, if it can be prevented, upon any surface, such as the retort, in which the heat is at a lower potential than itself, otherwise the combustion will be more or less destroyed 54 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS and incomplete, and also the cutting heat of the flame will rapidly destroy the retort or brickwork upon which it impinges. The flame should have full play, so that the retorts may be FIG. 21. heated by radiation from the flame, and afterwards by conduction from the products of combustion. This points to a large combustion chamber, and the larger this , ... . -7f^r^ r ^v^ v ^'S*'^^^ FIG. 22. is the less liability there will be for burning out the centre retort Undoubtedly the ideal position would be to range the retorts in four REGENERATIVE SYSTEM OF FIRING 55 and even five tiers of two retorts each. The objection to this is that in small works, or works where charging and drawing machinery are not employed, difficulty would be experienced in drawing and charging the top tiers of retorts. On the principle of regeneration, as applied to the heating of retorts, it may be pointed out that dry air, though diathermanous to radiant heat, takes up heat with extreme rapidity when brought in contact with a hot surface. It is not necessary, therefore, that the hot-flue passage through which the secondary air is caused to travel in order to be heated before coming in contact with the combustible gases from the generator, should be long extended and tortuous in its course. The advantages of the so-called regenerative arrangements as applied to retort furnaces are due not only, or chiefly (though this is important) to the heating of the secondary air, which is readily accomplished, but largely to the circumstance that the heat of the waste gases, as the latter traverse the passages con- structed alongside the furnace, is at a potential higher than that to which the brickwork in the base of the setting, and in the sides of the generator in the absence of the waste gas flues, could possibly attain. The effect of this is to insulate, as it were, the heat of the furnace, minimizing outward radiation and conduction. Heat, like water and electricity, tends to establish an equili- brium ; and the lower the temperature of a body in contact with another at a higher temperature, the greater the abstraction of heat from the latter by the former. From this it will be evident that the function fulfilled by the heat of the waste gases cannot properly be considered as " regenerative," in the strict sense of that word. Their tempera- ture is necessarily lower than that of the furnace and the inside of the oven. Heat cannot travel from a lower to a higher potential any more than water under normal conditions can travel uphill, and therefore it is not possible for the lower temperature to " regenerate " the higher. The chief function of the heat of the waste gases is by insulation, as already explained, to conserve, in the ratio of their own temperature, the heat generated by com- bustion in the furnace. If it were possible to enclose the heated ovens of a retort stack on all sides with an envelope of heat, it is obvious that the heat of the ovens would be conserved, a higher and steadier temperature maintained, and that economy of fuel would resuit. 56 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS At the risk of some repetition, it may be pointed out that the secrets of success in generator furnace-building and retort-setting are (1) To make sure that the system adopted is a good one. (2) To ensure a sound, unyielding, and dry foundation. (3) To use only the best materials and workmanship. (4) To have the joints of the brickwork throughout as thin and close as possible. And in the working of these (1) To get up the heat very slowly and gently at the outset, drying the brickwork gradually and thoroughly at a low temperature. (2) To charge the producer with hot coke as drawn from the retorts. (3) To regulate with care the air supply, both primary and secondary, and the exit gases, and keep the ash-pans full of water. (4) To insist on the generators being kept full of coke. If this is not done, CO 2 instead of CO will be produced in them, the concentrated heat melting down the brickwork instead of doing good service in the ampler area of the retort oven. The generators should be filled up every time the retorts are drawn. If a gas manager has complaint to make of the regenerative system and settings and their results, then one or other, or all, of the above points have been neglected. If the "Bonecourt" system for producing radiant heat by means of flameless incandescent surface combustion can be eco- nomically applied to the retort furnaces in a gas-works, it will be an advance in the practice of carbonization. Inclined Retorts. Following the example of M. Coze, of Rheims, settings of seven, eight, and nine retorts placed at an angle of about 32 degrees, have been adopted by many engineers in this country. That the modern settings of inclined retorts are a success, so far as the actual carbonization of the coal goes, there can be no doubt. As to whether they would be financially so, if applied generally in the smaller works, is open to question. Where it is impossible to reduce, in any material degree, the manual labour already employed, and where there is therefore INCLINED RETORTS 57 little, if any, likelihood of a reasonable return being made on the extra capital expended on an installation of inclines, the older system of horizontal retorts must still be retained. Again, with regard to the very large works, where power-stoking is already employed in such a way as to show an appreciable reduction in the cost of carbonization over the hand system of stoking, and allowing for interest on the capital outlay on the machinery, little or no advantage could be looked for by a substitution of inclined retorts. There is, however, between the small and the very large works, a vast number of medium-sized works not large enough to allow of the application of power-stoking being profitable, where the introduction of inclined retorts would be of material advantage, and would show a reduction on the cost of carboniza- tion, including all capital charges. There were two great difficulties to be overcome before inclined retorts could be worked satisfactorily. The first difficulty was with regard to the uniform heating of the retorts, the tendency with the earlier installations being for the top end of the retort to become considerably hotter than the lower end. This difficulty has been overcome by" building a solid division wall separating the front portion of the setting from the back portion, each being worked by its own. dampers and having its own secondary air supply. The regenerative system of heating is employed for these settings, with the furnace on the drawing side of the stack. The second difficulty was with regard to the even distribution of the coal along the bottom of the retort. In the original Coze system, the mouthpieces were a prolongation of the retorts, and were bent upwards, all reaching to the same level. The fall of coal, therefore, from the tipping waggons took place from one uniform level, which was 8 ft. 4 in. higher than the bottom tier of retorts, 6 ft. higher than the middle tier, and 3ft. 9 in. higher than the top tier. It is evident that if a drop of 3 ft. 9 in. was right for the higher tier of retorts, one of 6 ft. and 8 ft. 4 in. could not be right for the middle and bottom tiers, the retorts all being inclined at the same angle. As a matter of fact, irregular charging was the result. In the modern installations of inclined retorts, instead of the 58 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS mouthpieces being bent upwards and brought to one common level, with trucks containing the coal passing above them, the retorts are stopped off level with the front of the stack, and are provided with cast-iron mouthpieces and lids as for the horizontal retorts. A continuous coal-storage hopper extends the whole length of the house, and the coal is fed into the retorts by means of travelling measur- ing chambers and adjustable shoots. Not only is the system of inclined retorts a great advance in the method of charging, but it is also equally ad- vantageous for discharging the resul- tant coke. This slides out by gravity on opening the bottom lid and re- moving the stop which is put in to prevent the coal sliding into the mouthpiece. Sometimes the coke will stick, but it can easily be set in motion by pricking with an iron rod. With the advances that have been made of recent years in the construc- tion of conveying machinery, the hot coke can be conveyed straight from the retort house to the coke store or open yard, and quenched on its way. In Love's system of inclines (Fig. 23), the retorts are set at an angle of 45 degrees, whereby a heavier charge, FIG. 23. and even a full charge of coal, and an easier discharge of coke, are obtained. This form of setting marked the advent of full-retort charges. Gait ing. A setting should never, when it can be avoided, be put into action immediately on completion, as the application of strong heat to the damp clay is liable to crack and open the joints and cause " short-circuiting," besides destroying the brickwork. The setting ought to be allowed to stand at least fourteen days, in order that it may be gradually dried and hardened. A slow MACHINE STOKING 59 fire should then be lighted in the furnace and kept going for another fourteen days to complete the drying process, the damper to the main flue being entirely closed, but the feeding door and the sight and hand holes kept fully open. On putting the bench or oven into action, the heat should be applied gently at first, the damper being gradually opened a little more each day until the proper temperature is attained. When the retorts have reached a dull red heat, a light charge of coal thrown into them assists the development of the required tem- perature, and tends to preserve them in good condition. By careful attention to these points, the cracking of clay retorts on first " gaiting " may be entirely avoided. A setting will break down not only from wear and tear and high heats, but owing to the contractility of the materials com- posing it. The lesson to be drawn from this is that only such materials as are thoroughly shrunk by hard firing should be used. Machine Charging and Drawing of Horizontal Retorts. The problem of applying machinery to the charging and drawing of retorts is one which has occupied the minds of gas engineers from the very introduction of gas-lighting. A retort house of to-day is not considered complete unless some effort has been made to minimize the arduous labour of charging and drawing the retorts by hand. The extent to which mechanical charging and drawing appliances can be applied to any particular works depends to a large extent upon the number of retorts in use, so that the machines adopted may show a reasonable return, in the direction of labour saving, on the extra capital expended. The retort charging machines in use for horizontal settings are of two kinds. First, those in which a portion of the machine actually enters the retort, either as a scoop or pusher ; and second, the arrangements whereby the coal is projected into the retort. The West, Arrol-Foulis, and Fiddes- Aid ridge are of the first kind. In the West power stoker (Fig. 24), the coal is fed automatically to the scoop during the time that this is making its progress to and into the retort. The machine may be fitted with a large coal hopper to carry a supply of coal for a number of retorts, or it may be provided with a small receiving hopper. In the latter case it is necessary to provide overhead hoppers extending the whole :,: yi" i ::-:-:>:- 5 ?:?. :->.? an ir- IiF marhrm iraiQk TKTWET. The ATrnVFrmTk madni't 7 -rreaaK of a "fHsker 1 measured gnL' ; : ~ :.T mactnii MACHINE STOKING 61 25. The Arrol-Fonlis Power Stoker, 62 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS A discharging machine, Hunter & Barnett's patent hydraulic coke pusher, has been designed to work along with the Arrol-Foulis charger. This consists of a mild steel framing attached to a carriage fitted with traversing wheels. The beam with actuating rams for working the pusher head is suspended from the top of the framing by chains and pulleys to give it its rising and falling motion so as to suit different heights of retorts. The hydraulic rams for the pusher head are made telescopic, and have internal drawback arrangements. The working stroke of these machines is usually 20 ft., though they can be made to suit any length of retort. The Fiddes-Aldridge simultaneous charger and discharger (Fig. 26) is one of the latest types in use with horizontal retorts. The machine consists of a movable inner frame constructed of mild steel, in which is placed the necessary gearing together with the motor and controlling gear. This frame is suspended by wire ropes from an outer frame of mild steel running on rails beneath a series of coal hoppers, or one continuous coal hopper. The coal from the overhead hopper is automatically fed into an adjustable measuring chamber carried on the top of the outer frame. It then passes downwards through a telescopic shoot into a conveyor chain. This consists of pairs of parallel sheet plates placed vertically, and kept apart by distance pieces or archstays. Archstay pushplates are swung in such a manner as to carry the coal in a forward direction only. The coal in entering the chain is carried forward by means of the pushplates through the retorts into the discharging side, at the same time pushing out the coke from the previous charge. The coke having been discharged from the retort, the motion of the chain is reversed and the pushplates automatically rise over the deposited coal, and level same on withdrawal. This machine is usually driven by electricity, but rope driven, compressed air, and hydraulic power can also be utilized. The second method of charging horizontal retorts is well illus- trated in the De Brouwer system (Fig. 27). The machine is driven by electricity, a dynamo of about three horse power being all that is required to work same. The machine consists of a light iron framework suspended by chains to a travelling carriage running on rails beneath a line of overhead coal hoppers. Fixed in the framework is a large pulley with a grooved face. MACHINE STOKING FIG. 26. The Fiddes-Aldridge Power Stoker, 64 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS A funnel-shaped mouthpiece guides the coal from the overhead hoppers on to the back of this grooved-face pulley. Against the back and the bottom face of the pulley there travels a leather FIG. 27. The De Brouwer Power Stoker. belt working on two small pulleys. So that the top side of the belt is at a right angle with the large grooved pulley working in the angle. The coal travels down the spout formed by the grooved pulley MACHINE STOKING and the leather belt, and the centrifugal force imparted to the coal is sufficient to shoot the same to the far end of a 2O-ft. retort. Suitable controlling power is fixed to the machine to diminish the speed of the belt, and thereby enable the coal to be laid from back to front of the retort in an even layer. A discharging machine has been designed to work in conjunction with the projector. A complete stoker or charging and discharging machine (Fig. 27) by the same makers is electrically driven, with travelling FIG. 28. Dempsters' Stoking Machinery. and hoisting gear, and is designed to work under a set of continuous overhead coal storage hoppers. R. Dempster & Sons' stoking machinery is of the projector charging and pusher discharge type. The^charging machine, Toogood's patent, rotates at 80 revolu- tions per minute when charging a 20-ft. retort. The pusher discharger machine, Dempster & Ordish's patent, is electrically operated, the motion being imparted by steel wire ropes, and the ram operates its own controller as it ap- proaches the end of each stroke. The ram is made in two 66 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS sections, which the makers consider is an improvement over the three sections. A combined machine or complete stoker (Fig. 28) has been FIG. 29. The Drake Power Stoker. designed in which the projector and discharger are mounted on one framework, and is provided with rack and pinion motion for raising and lowering. A coal hopper of a capacity of 25 to 30 cwt. is fixed at the top MACHINE STOKING 67 of the main frame and is provided with a feed regulator to the charger. An index gear records the progress of the charge. Drake's charging and discharging machine (Fig. 29) is of the push drum and projector side feed type, driven by electric motors and provided with the necessary appliances for collecting the current from overhead copper wires. The projector consists of a cast-steel centre disc fitted with mild steel vanes on both sides. These are fed by a side feed, and the coal is projected in two layers at the same time into the retort to any depth, or to completely fill it. Claim is made for an advantage of the side feed over back or single feed. The pusher is constructed of steel links wound spirally round a drum, forming a rigid strut in unwinding, keeping the pusher always in a straight line in the centre of the retort, so preventing wear and tear on the bottom. Manual Stoking Machinery. For medium-sized works a manual stoking machine has been designed by Mr. West, so that, whilst manual labour is still required, the stoking is a much easier operation. Overhead fixed coal hoppers supply the coal to a travelling hopper running on rails in front of the retort bench, and a light frame suspended beneath this hopper carries the " charger." The charger is filled by a feed box immediately beneath the mouth of the coal -shoot, and is governed by a hand wheel. The charger consists of two semicircular scoops carried by a light carriage on wheels, which are arranged so that by twisting the drawing handle after the scoops are in the retort, the scoops turn over and the coal is deposited. Suitable propelling gear worked by a hand wheel enables the machine to be easily moved along the retort house. The drawing machine consists of a rake bar and frame suit- ably mounted on a travelling frame and capable of being raised or lowered to the several tiers of retorts. Another machine for use in medium-sized works is the " Rapid " manual and power charging apparatus of Biggs, Wall, & Co. It consists of an overhead travelling frame with a pair of rails running parallel to the length of the retort house. On these rails a carriage with lifting gear is arranged, and from the lifting gear the charging scoop is suspended. The length of travel of the carriage is such that the scoop isjpushed half-way along the retort, but the impetus F 2 68 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS '"\\ . FIG. 30. The Dessau Vertical Retort Installation. VERTICAL RETORT SETTINGS 69 given to the scoop by the driver is sufficient to carry it the full length of the retort. Vertical Retorts. Retorts set in the vertical position are now being largely adopted both abroad and in this country. The Dessau or Bueb setting, Fig. 30 (called after its inventor, Dr. Bueb) was the first vertical retort system to be adopted on a commercial scale. This setting, latterly known as the " Dessau " (from the town in Germany where it was first adopted) is an inter- mittent system of carbonizing coal that is to say, the retort is filled with coal and then closed until distillation is complete, when it is opened and the resultant coke withdrawn. The settings are in parallel rows with as many as eighteen retorts to an oven ; the length of the retorts being either 13 ft. ij in. or 16 ft. 5 in., according to local requirements. The heating of the retorts is on the regenerative principle, and is accomplished by a generator arranged alongside the oven. A feature of the heating is that the temperature is so regulated that the hottest part of the retort is at the base. ; Above the retort stack are a series of hoppers into which the coal is deposited by means of an elevator and tipping waggon. From these hoppers the coal is fed into a travelling charger which shoots it direct into the retorts. In this system, advantage is taken of the full retort of red hot coke for the production of a proportion of " blue " water gas, by the injection of steam near the end of the period of distillation. Woodall-Duckham. This is an automatic and continuous system of carbonization (Fig. 31). The coal is so regulated in its descent that on entering at the top it is gradually carbonized in its continuous passage through the retort, and is converted into coke by the time it arrives at the bottom. The installation usually consists of settings of four retorts with one or two generators to each setting according to the size of unit required, and is supported on a steel joist floor, supported by steel stancheons. The retorts are 25 feet long, formed of bricks, grooved and tongued, and tapered from bottom to top. They are heated on the regenerative principle, with vertical flues. Combustion of the gases takes place at the top of the flues, and the arrangement is 70 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS such that the heat can be regulated in its application to any portion of the retort. The coal and coke hoppers are formed in one continuous line above the retorts and supported by stanch eons. The quantity of coal admitted to the retorts, and the rate at which the charge descends, are both automatically governed FIG. 31. The Woodall-Duckham Vertical Retort Installation.- by the rate of extraction of the coke from the bottom of the retort. The coal feeding device consists of an auxiliary or feeding hopper attached to the mouthpiece casting. This is supplied with coal from overhead storage hoppers. Each feeding hopper has an indicator attached by which the rate of coal feed and also the position of coal in the hopper can be ascertained. There is a continuous discharge of coke into a receiving chamber fixed at the bottom of the retort, by means of what is called an VERTICAL RETORT SETTINGS extractor roller. This, as it rotates, allows the coke to pass over it into the receiving chamber, which has a capacity of three hours' discharge. FIG. 32. The Glover- West Vertical Retort Installation. Glover-West. The Glover-West (Fig. 32), like the Woodall- Duckham, is an automatic and continuous system of carbonization, the retorts being 23 or 25 feet in length and tapered from bottom to top. The number of retorts to an oven is determined by the capacity of the plant. In the Manchester installation there are 72 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS eight retorts to an oven, and each setting is provided with its own generator. The coal is elevated from the store to an overhead bunker, from which it is delivered into a feeding hopper placed above each retort, from whence it gravitates into the retorts at a speed regulated according to the discharge of the coke. At the base of the retorts a coke extract or -is fitted. This consists of a slowly revolving worm of special design, made in two halves, one half being detachable from the other. The object of this is to provide, by partially removing one half, a space for inspec- tion and access to the retort. A receiving chamber is fixed below the extractor to receive the coke, and this is discharged at intervals of two hours. The retorts are heated on the regenerative principle. A feature of the heating is that the secondary air supply is so arranged as to utilize the heat from the hot coke, in the receiving chambers. The effect of this is that the coke, when discharged, is comparatively cold, and there is great economy in fuel consumption. General Remarks. It has been proved, that with certain coals distilled in vertical retorts, an increased make of gas per ton can be obtained, over either horizontal or inclined settings. In the continuous systems there is a complete absence of all the disagreeable conditions which prevail with other methods of carbonization. There is also a saving in ground area over horizontal and inclined systems. It is claimed that the composition of the gas as delivered from the retort is more uniform than in the horizontal and inclined systems, and that the coke, tar, and ammoniacal liquor are improved in value. Furthermore, and this is all important, there is a complete absence of naphthalene deposits in the street mains and services where vertical retorts are used. The advisability of the adoption of vertical retorts depends to a large extent upon local circumstances. That the system offers advantages which the horizontal and inclined systems do not possess, is unquestionable. Whether the advantages are applic- able to each individual works is for each engineer to consider. That there is a decided change in the character of the coke produced is certain. ELEVATING AND CONVEYING MACHINERY 73 Coal Elevating and Conveying Machinery. During recent years much progress has been made in minimizing the labour involved in the handling of coal. In the case of works situated near to a quay or canal, three systems of mechanical transport present themselves for the removal of the coal from the barge, viz. : (i) a travelling jib crane and grab ; (2) an adjustable bucket elevator; and (3) the removal of the coal by a telpher or temperley transporter. In the case of works situated near to a railway, a siding is generally brought into the coal store. The coal is thence conveyed by means of a band conveyer to the breakers and bucket elevators. Where circumstances permit, a high level siding may be con- structed and the coal waggons fitted with "bottom doors allowing the coal to be deposited by gravitation into bunkers fixed above the breaker-pit. A handy method of emptying the coal in bulk out of the waggon is by the application of a waggon tipper. This consists of an appliance for raising the hind part of the waggon to such a height as to allow the whole of the contents being discharged at once. The telpher arrangement (see next page), for the conveyance of coal has not yet been largely adopted, but there are many works where this method cf transport would undoubtedly be found advantageous. It is usual to have a jigger-screen in front of the breaker to separate the dust and the small pieces which are passed directly into the boot of the bucket elevator. The coal after being broken is raised from the breaker-pit to the storage hoppers in the retort house by means of an elevator of the bucket type, which, in turn, feeds a push-plate conveyer running the whole length of the house immediately above the hoppers. The coal then falls from the trough of the conveyer into the hoppers through openings fitted with sliding doors. Hot Coke Handling Plant. The removal of hot coke from the retort house is one which plays an important part in the economy of retort house labour, and with the advent of heavy charges of coal, and coke discharging machinery, mechanical removal of the hot coke is necessary. In small works, however, the removal of the coke in barrows cannot be improved upon. There are at present chiefly three systems by which the removal 74 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS of hot coke may be effected, viz. : (i) by steel barrows propelled by hand, or rope haulage ; (2) by endless chain conveyers ; and (3) by some form of telpher or crane arrangement. The first method, although in many cases efficient for its purpose, is not one we can recommend in preference to the chain conveyer. There is always a tendency for the coke to be unduly broken in its fall from the retorts to the barrows. The second method, that of the endless chain conveyer, is largely adopted, and consists of a chain of special design working in a trough generally about 2 ft. 6 in. wide, and placed either on the stage floor or underneath. There are many makers of gas plant who make a speciality of conveyers for hot coke, but the general principle of these is practically the same. The third method, the telpherage system, has many points in its favour. The coke is deposited from the conveyers into steel skips and these are transported to the storage hopper for cart and waggon loading, or to the coke yard as required ; or the skips may be taken direct to the front of the retorts to receive the coke. The telpher travels along a length of overhead mono-rail, and is constructed of steel with a covered-in cab for the workman in charge, in which are placed controllers and other levers. Two electric motors are provided, one for travelling and one for hoisting, and they are usually of the enclosed or dust-proof type. The quenching of the hot coke is effected either by hose pipe or sprinklers, or by immersing the skips with their contents in a water tank. Carbon Deposit in the Retorts. In the distillation of coal a deposit of carbon takes place within the retorts, which, if allowed to go on accumulating, eventually seriously contracts their internal area, and causes a diminution in the heats. This deposit is due principally to the decomposition of the hydrocarbons that are first formed, and to the pressure produced by the resistance offered to the passage of the gas through the different apparatus. Its removal by scurfing with chisel bars in the ordinary way is always more or less attended with damage to the retorts ; the more so as they require to stand off for six or twelve hours, to loosen the carbon by the admission of air, before applying the bar. Different methods of scurfing have been tried with varying COKE SLAKING 75 success, the best probably being that by which a current of air and steam is made to impinge upon the carbonaceous deposit ; but, after all, the best plan of obviating the difficulty is to prevent the deposit as much as possible, by minimizing the dip in the hydraulic, or dispensing with the latter altogether (see p. 94), by employing an exhauster to reduce the back pressure, and by frequently scurfing the surface of the retorts with a rounded steel scraper. Coke Slaking. In the slaking or quenching of hot coke, water is a necessity. It is true that if the coke is drawn from the retorts into iron barrows, and a close cover placed over it, the confined gases, in the absence of atmospheric oxygen, will gradually arrest combustion in the mass ; and this method of dealing with the coke is sometimes adopted with a view to abating the nuisance of the escape of steam charged with sulphurous vapours from the retort house, and to preserve the coke for sale in a dry and bright condition. Where the production of coke is great, however, as in the case of large works, this is an incon- venient, if not impossible, method of dealing with the material. The quantity of water absorbed by the coke when it is slaked in the ordinary way is comparatively small, not exceeding, on the average, 15 per cent, of the weight of coke in the first instance, and the bulk of this evaporates when the coke is deposited out- side the retort house in the open air, about 3 per cent, of moisture being permanently retained. Proportion of Coke used for Firing. In moderate-sized works, skilfully conducted, about 3j cwt. of coke, or 25 per cent, of the production (say, 13 cwt.) of coke per ton from Newcastle and other high-class bituminous coals, is used as fuel to carbonize one ton of coal. In large works, under the most favourable conditions, and with the ablest management, the consumption of coke for heating the ovens may be reduced 'as low as 15 to 20 per cent, of the produc- tion. With inclined and vertical retorts it has been reduced to 10 per cent. In small works, one-third the production of coke is nearer the average consumption. Radiation from the benches is reduced, and fuel economized to an extent greater than might be supposed, by temporarily brick- ing up the furnace doors and the mouths of all retorts in beds not in use in proximity to others in action. 76 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Tar used for Firing. Where tar is unmarketable, or but of low value, and there is a ready sale for coke, the former should be employed in heating the retorts. Its application is exceedingly simple. When applied to an ordinary furnace, the ash-pan is first filled up with breeze ; the door is then removed and the door space bricked up, leaving two holes, one above the other, about 4 by 3 in. The tar is supplied through the top hole, the bottom hole being for the admission of air, and to allow of the fire being stirred when required. A piece of 2-in. angle iron, or a grooved fire-clay slab, or other convenient channel, is inserted into the furnace through the top hole, and down FIG. 33. this the tar is made to flow in a stream about T % in. thick. (Fig. 33-) The tar can be taken direct from the hydraulic main, or back main, in the bottom of which a i-in. wrought-iron ferrule, having a stop-cock attached, is screwed. A J-in. reducing coupling is then put on, and this size of pipe brought down to the side of the . oven, where the tar is supplied to the trough through a nozzle of the proper dimensions ; or a jet of steam directed through the nozzle may be used to spray the tar into the furnace. As the hydraulic and back mains will not supply all the tar necessary, a pipe should also be brought from a tank or cistern erected in some convenient place outside the retort house. If this tank is placed inside the retort house, the dust arising from the RETORT STACK BRACING 77 coal mixes with the tar and hinders its flow. Into this tank a supply of tar should be pumped from the tar well as required. The objection to the use of tar as fuel, as above applied, is that the intense heat which is generated at the point of combustion soon destroys the arch or tiles underneath the middle retort, breaking the latter down. As this retort, in the ordinary setting of fives and sevens, is the one usually first burnt out, it is advisable to restrict the use of tar to those benches that have been at work for a length of time, and in which the middle retort is either much burnt or already destroyed. Numerous other expedients for firing by tar have been put forward, but the above has the merit of efficiency with cheapness and extreme simplicity. In the event of a deficiency in the^supply of tar, this furnace is readily reconverted for coke firing. About 50 gallons of tar used as fuel will carbonize 2j tons of Newcastle coal, or a mixture of Wigan coal and cannel, in twenty- four hours. At this rate about 6 gallons of tar are] equal to a sack 3 (bushels) of coke. Retort Stack Bracing. The brickwork of the ordinary retort stack is braced together with buckstaves, cross girders, and tie rods, applied both longitudinally and transversely, to enable it to resist the expanding action of the heat. The buckstaves are made of steel, either rolled H (Fig. 34) or rail section (Fig. 35), or formed of two flat bars 6 in. FlG 34 FlG wide and 2 in. thick, with cast-iron distance pieces between, through which the two flat bars are riveted together with f-in. rivets (Fig. 36). The cross girders, which also serve as supports for the hydraulic and back mains, are of rolled H section, excepting where the buck- staves are as shown in Fig. 36, when the cross girders are usually constructed of channel and angle steels and transverse tie rods ij-in. in diameter. If the transverse tie rods be taken through the division walls of the stack they should be encased in 4-in. cast-iron piping, so as to allow of air circulating round them, otherwise they are soon burnt away. The longitudinal tie rods are of round mild steel, or wrought-iron y8 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS from 2 to 3 in. diameter, depending upon the size of the stack, threaded with square threads and furnished with open coupling boxes and strong hexagon nuts and washers. A f-in. steel plate, extending the width of the stack, and 2 ft. deep, placed in a recess at the two end or buttress walls, opposite the springing of the arches, and underneath the buckstaves, helps materially to bind the brickwork together, and prevents undue expansion. The boss A, on Fig. 36, with hole therein, is intended to receive the wrought-iron pipe, i-in. diameter, leading from the 3-in. water main on the top of the retort stack. To the end of this pipe a brass swivel is attached, and from this again a piece of i-in. steam tubing, n in. long, projects, having a brass swivel-cock at its end ; a tube of fin. diameter is screwed thereto, and terminates in a 4-in. brass rose jet through which water is discharged for slaking the coke as it is drawn from the retorts (Fig- 37)- The question of bracing the retort stack becomes one of much greater importance when treating with inclined retorts as compared with "those set horizontally. Not only are the front, back, and end buckstaves to be strengthened, but additional vertical and horizontal bracing is required for the front and back walls of the setting. For a stack containing five settings of eight 20-ft. inclined retorts each, the following bracing is suitable : Six front buckstaves formed of two 8 in. by 6 in. rolled steel joists with J-in. cover plates. Six back buckstaves, 16 in. by 6 in. and 62 Ibs. per foot rolled steel joists. Eight end buckstaves, 16 in. by 6 in. and 62 Ibs. per foot rolled steel joists. Six transverse girders, 12 in. by 6 in. and 54 Ibs. per foot bolted to front and back buckstaves and resting on brackets. Four longitudinal rods 2j in. diameter with forged-steel open coupling boxes. Bracing to front and back walls of setting of 8 in. by 6 in. and 7 in. by 5 in. rolled steel joists. In addition to binding the brickwork of the setting together, the back buckstaves carry the coal storage hoppers and shoots (Fig. 7). RETORT MOUNTINGS 79 Furnace Fittings These consist of the ash-pan, furnace and clinkering doors, sight -hole boxes, fire-bars and bearers, drip- plates, etc. The particular design and size of the furnace fittings will depend upon the type of furnace adopted. Before heating a retort stack for the first time, care should FIG. 37. FIG. 38. . be taken that the tie rods are not screwed up so as to put a strain on them, otherwise, on the stack expanding, either the threads will be torn FIG. 36. off the tie - rocl coupling or the rods themselves will snap. The following are the details of the fittings required for a direct- fired furnace : The ash-pan may be of wrought plate-iron T \ in., or of cast- 8o NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS iron -jZg. in. thick. The usual dimensions are : Length 5 ft., width 12 in., depth 10 in., outside (Fig. 38). The pan should always be kept charged with water'. The water, heated by the glowing coke, gives off steam in considerable volume, and this, rising under- neath and between the furnace bars, contributes to their durability by keeping them comparatively cool. A tidy fire-about, with the ash-pan charged with water and reflecting the bright fire between the bars, is an indication of good stoking. The grate bars are two or three in number and 30 in. to 36 in. long, made of 2-in. wrought bar-iron, and supported on two bear- ing bars 3 in. square in section, 24 in. long, their ends built into the brickwork. The furnace frame and door (Fig. 33) are of cast-iron, the latter with pocket to receiye a tile or fire-brick lining. Cast-iron cleaning-out and sight-hole boxes with plugs are built into the front wall of the setting. For a generator or regenerative furnace the ash-pan needs to be about 2 ft. 9 in. wide, 5 ft. long by 10 in. deep, and the furnace bars and bearers made to suit the width of furnace. The furnace (or clinkering) door and frame differs from that for a direct-fired furnace, when it is designed so as to admit of the regulation of the air passing through it to the furnace. The fuel for the furnace is admitted through a charging door provided with an air-tight cap. The sight-hole boxes and plugs are similar to those for a direct- fired furnace. Other furnace fittings are the drip-plates and their bearers. These are placed across the furnace behind the clinkering door, and are usually 6 in. wide and f in. thick. Retort Mouthpieces. The retort mouthpiece, of cast-iron, is round, Q -shaped, or oval, to suit the retort, and, for horizontal retorts, usually 15 in. deep from front to back. The top and bottom mouthpieces for inclined retorts are different in size and shape, owing to the increase in width of the retort at the lower end ; and since, with inclined retorts, the gas is usually taken off by one ascension pipe, and that at the lower end of the retort, there is no necessity for the ascension pipe socket on the top mouthpiece. The usual dimensions of the lower mouthpiece are 24 X 16 in., and those of the top mouthpiece 22 X 16 in. RETORT MOUTHPIECES 81 Lugs are cast on the sides of the mouthpiece for the door fastenings. The mouthpieces are either provided with a flange for bolting to the retort, or with a socket for fitting round the retort. In either case, rails of rail-steel should be placed across the front of the flanges and secured to the front buckstaves, so as to keep the mouthpieces in position. The following are the details of a mouthpiece for an oval retort FIG. 39. FIG. 40. FIG. 41. FIG. 42. 21 in. by 15 in., and will serve as a model for any other size and shape, allowance being made for varying dimensions. (See Figs. 39 to 42.) Depth from front to back, over all, 15 in. Thickness of metal in front portion, f in. ,, ,, in lip, i in., and planed level. in flange, i in. Width of flange in front, 3f in. ,, at back, 4 in. Number of bolt holes, eight ; diameter, i in. Ear-box on each side, with slot 2 in. by f in. Socket, to receive end of ascension pipe, 5 in. in height and 6J in. diameter inside ; centre, 5 in. from front. Bolts, for securing mouthpiece to retort, eight ; diameter, | in. ; screwed and nutted at both ends. Lugs of wrought-iron, 14 in. long, 2 in. broad, and f in. thick ; one with jaws and pin for hinging cross-bar, the other G 82 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS cranked and notched as in Fig. 42. Slit at opposite end, 2 in. long, J in. wide ; wedged to ear-box. Cross-bar of wrought-iron, 25 in. long, 2 in. broad at each end, and J in. thick. Middle part 2\ in. broad, swelled out to 2 in. thick, with I in. screwed hole through centre. Screw, 10 in. long, with square thread 7 in. of its length. Cross handle, 14 in. long, f in. round-iron. Lid, J in. thick, plate-iron, dished, with lug on each side. Cements for Jointing Mouthpieces To clay retorts Three-fourths by weight of fire-clay. One-fourth by weight of iron borings. When ready to connect, mix with ammoniacal water. Use no sulphur. Or 20 Ibs. gypsum (calcium sulphate) made into a pulp with water. 10 Ibs. iron borings saturated with a strong solu- tion of sal ammoniac. Mix well together till of a consistency fit for use. In fixing the mouthpieces to clay retorts, the flange or face of the retort should be notched all over with a sharp-pointed hammer, or a slight channel cut all round (this is best done by the retort maker in course of manufacture), for the cement to bed into when the bolts are screwed up. For iron retorts 2 Ibs. fine clean iron borings, i oz. sal ammoniac, i oz. flowers of sulphur. Mix together and keep dry. When required for use, add water to bring the mixture to a proper consistency. Besides being fastened with bolts, mouthpieces should always be supported by cross-bars pressing against the flanges, the ends being secured to the buckstaves. Luting for Retort Lids. Ordinary lime, or spent lime from the purifiers mixed with fire-clay or common clay, and worked up into mortar. The following~makes a tough, persistent luting : 1 part lime. 2 parts moulding sand. Ground up together, with water, in a mortar mill. CHOKING OF ASCENSION PIPES 83 Self -sealing retort lids and mouthpieces are generally used for horizontal retorts, and exclusively so for inclined, and are of the eccentric lever or eccentric screw type. The lid is not removed from the mouthpiece in charging the retort, but swivels round with the hinged cross-bar, to which it is secured. It is made in any form to suit the shape of the retort, with upturned semicircular edge, faced true. This pressing against the flat edge of the mouth- piece, which is also faced, makes a gas-tight joint without the intervention of luting. The ascension or stand pipes are of cast-iron, and should not be less than 5 in. diameter for horizontal retorts. Pipes tapering from 6 in. to 5 in., and pipes 6 in. diameter, are commonly adopted. For inclined retorts the ascension pipes should not be less than 7 in. diameter. The best caulking material for ascension pipes at their junction with the mouthpiece socket is ordinary ground fire-clay, or slaked lime, made of the consistency of putty. These, when pressed down into the space between the spigot and socket, make a perfectly tight and durable joint, and are easily removed when the retorts need renewing. On the other hand, when the joints are caulked with iron cement, the labour in cutting it out and the risk of splitting the socket are considerable. Choking of Ascension Pipes. Ascension pipes occasionally become choked to a greater or less degree with thick tar, pitch, and other carbonaceous matter. When this occurs, it is well to let as many as can be spared at once stand off for a shift (pro- vided the retorts are in condition to admit of this), drawing the charge, and removing the bonnet or plug from the top of the bridge-pipe. The heated air making its way through the smallest aperture will thoroughly clear them of the obstruction. The causes of choking are various, and they are not always overcome. These are the chief : High Heats. Excessive heating is conducive to the decom- position of many of the gases formed, with the result that carbon is deposited either in the retort or in the ascension pipes or in both. In the early days when low distillation temperatures were in vogue, there was but little trouble with stopped ascension pipes. To the pipes being in too close proximity to the bench owing to the mouthpieces being too short. To great radiation of heat from the bench, owing to the front walls of the setting being too thin. G 2 84 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS To the charge of coal being laid unevenly in the retort, and to the latter being cracked and porous, allowing the furnace gases to be drawn in, and to the coal being left too close to the mouthpiece. To heavy dips in the hydraulic main causing heavy back pressure. Some coals are more liable than others to cause stoppages. A change^ in the direction of the wind will sometimes both cause and remedy stoppages. The remedies that are tried are : Causing water to trickle down inside of the ascension pipes. Coating the front walls of the settings with non-conducting cement to keep in the heat. Maintaining a level gauge in the retorts and a liquor seal in the hydraulic main, or dispensing with it altogether. After all, drawing off the thick tar from the hydraulic main and allowing free exit of the gas from the latter, and keeping the pipes cool, are the best preventives of choking. This latter may FIG. 43. FIG. 44. be accomplished to a great extent by making the front walls of the ovens I J bricks thick, so preventing undue radiation from the bench, and having the mouthpieces of the retorts so constructed as to allow of the pipes standing 6 in. or 8 in. away from the front wall of the oven. The Bridge and Dip Pipes are of cast-iron, and 5 in. and 6 in. are the usual diameters. The bridge-pipes are made in various useful THE HYDRAULIC MAIN 85 forms (Figs. 43 and 44). The chief consideration in the design should be to secure easy access to their interior for clearing purposes in case of blocking with thick tar. The following dimensions will be useful for a setting of horizontal retorts : Internal diameter of bridge and dip-pipes, 5 in. Height of bridge-pipe, 16 in. Width, centre to centre, 21 in. Connecting flanges, diameter loj in. Bolt-holes, four in number, centre to centre across, 8 in. Diameter of bolts, f of an inch. Many arrangements of the arch and dip-pipes, especially of the latter, have been patented, with a view to getting rid of the dip and consequently of mitigating, as is supposed, the trouble of stopped pipes. Any success attained, however, has not been such as to warrant their general adoption. The Hydraulic Main. The hydraulic main, as a general rule even in small works, should not be less than 20 in. in width at the water-level. Hydraulic mains of cast-iron are now only adopted in small works, mains constructed of steel or wrought-iron being both lighter and less liable to fracture. The usual section cf the main is that of a rectangle with the FIG. 45. FIG. 46. FIG. 47. FIG. 48. bottom dished to the extent of 4 or 5 in. (Fig. 49). This section of main has superseded those whose section was either G-shape (Fig. 45) with the flat side up, square (Fig. 46), or round (Fig. 47), which only serve for an accumulation of thick tar. The " Livesey " hydraulic (Fig. 48), is a great improvement on the old sections, and, but for the greater cost of manufacture, possesses all the advantages of the more modern section. The chief object of the modification in form is to allow only a shallow 86 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS depth of liquid, and this being kept in motion by the issuing gas, deposit to any great extent is prevented. Fig. 49 shows an arrangement of ascension, bridge, and dip- pipes, with hydraulic and back main, and valve between. The steel and wrought-iron mains are usually constructed with sides and bottom i in. thick, and top -f$ in. thick. The top plate is bolted with }-in. bolts to 3 in. by 3 in. by f in. angle-steel riveted to the top of side plates. Of course these dimensions would be modified according to the size of the main. Where cast-iron mains are adopted they should be f in. thick. FIG. 49. Instead of allowing the heavy tar from the hydraulic main to pass over with the gas, and by so doing allowing the tar to absorb a large percentage of the illuminating constituents, many arrange- ments have been adopted whereby the tar is taken from the hydraulic main by a separate main to that by which the gas leaves. A very good arrangement is that in which (Fig. 50) a 6-in. cast-iron main running beneath the hydraulic is connected to each section by a 4-in. branch with a valve, the lower end of the main being connected to a stand-pipe at the end of the stack. The stand-pipe should be of sufficient capacity to contain one day's production of tar. To govern the depth of seal within the hydraulic main 'there THE HYDRAULIC MAIN is a 3-in. overflow pipe with a weir valve connected to the stand-pipe at the level of the liquor in the hydraulic ; the over- flow pipe is carried down to the ground and there connected to the tar main. A water connection to the hydraulic, and a tar outlet with valve connected to the bottom of the stand-pipe, complete the apparatus. Its working is as follows : The hydraulic main and stand-pipe FIG. 50. are filled with liquor, and the weir valve set so as to give the required seal in the hydraulic main. As the tar is formed, it settles to the bottom of the hydraulic, and flows down the tar-pipe beneath to the stand-pipe, which it gradually fills, the displaced liquor flowing over the weir valve and down the overflow-pipe. Each day the tar is run off from the stand-pipe and fresh liquor run into the hydraulic, care being taken that the tar does not flow away quicker than fresh liquor is supplied. The hydraulic main should rest on brackets secured to the cross girders. The height of the cross girders above the top of the stack is from 2 ft. to 2 ft. 6 in. NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS To erect the main on standards resting on the top of the bench is not a good plan, as any settlement of this will affect the seals in the hydraulic. In some instances the hydraulic main is placed against the retort house wall, being supported on brackets or cantilevers attached thereto. This plan necessitates a strong wall to bear the weight of the main and its contents, and also a long length of pipe overhead, fixed in an inclined position, attached at one end by a bend to the ascension pipe, and at the other to the dip-pipe on the main. In addition to the hydraulic main, a second or back main is often laid along the bench, and connected to the former at the water- level, at each bench or oven, by a branch with a valve upon it for closing when necessary. This secondary main conveys the gas and fluid products from the retort house, and admits of the isolation of the hydraulic main over each setting of retorts. By this arrangement it is easy, in case of any disturbance of the bench through settlement or otherwise, to restore the several short lengths of hydraulic main to the true level. Retort Mouse Governors. The improved results that can be obtained in carbonization, both as regards quality and quantity of gas, by the installation of a retort house governor, in addition to the ordinary by-pass governor employed with the exhauster, are now recognized. There are many makes of retort house governors, but the construction is either of the float or counterbalanced type. The objects of the governor are to regulate the suction exerted on the retorts by the exhauster in the direction of preventing oscillation, and to maintain more constant pressure conditions in the hydraulic main. The governor is placed on the foul main and generally about 6 ft. from the end of the retort stack. Retort House Tools and Appliances. For charging retorts by hand, the shovel or the scoop is used. Shovels with riveted handles are not good in or about a retort house. The heat soon causes the wood to dry in, and the rivets give way and become jagged, lacerating the hands of the men who use them. Socketed handles are the best. A good handy-sized shovel for charging retorts of the ordinary size is one 16 in. long by n in. wide. Firing shovels (for coke) are best made an inch wider. Both should be well turned up at the sides. RETORT HOUSE TOOLS AND APPLIANCES 89 The scoop (Fig. 51) is a semicircular trough of sheet -iron or steel, the length of half the through retort, and of capacity to /9. = IO ^ S q f t j n ^ mouthpiece 21 in. by 15 in. by 15 in. there is, say, 6J sq. ft. In 3 ft. of 6-in. pipe there is 4^ sq. ft. Total, n sq. ft., or more than sufficient cooling surface to produce the observed result. " Calculating in a similar manner for the difference between the temperature at 3 ft. from mouthpiece 174, and that in the bridge-pipe 132 Fahr., I find there is similar accord between theory and practice, calculation and observation, which appears to give further ground for accepting the assumption started with as a correct one." H 2 ioo NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS enriched with oil in the carburettor as above mentioned, which imparts to the gas its light-giving properties. The process of manufacture may be continued as long as the fuel in the generator is sufficiently high in temperature to reduce the carbon dioxide to the monoxide. Usually, after six to seven minutes' gas making the temperature of the fuel falls too low for this reduction to take place. The steam and oil supply is then shut off and an air blast turned into the generator, thus again raising the temperature of the fuel. A period of three to four minutes is generally sufficient, after which the steam and oil are turned on again. A relief holder is necessary in the working of a carburetted water gas plant in order to store the intermittent makes, and to supply a constant flow for mixing with the ordinary coal gas. The following figures may be taken as fair average working results and costs in this country of manufacturing 1000 cubic feet of 18 candle carburetted water gas, with oil at 2\d. per gallon and coke at los. per ton : Illuminating power, tested with the Metro- politan argand burner No. 2 . .18 candles Candles per gallon of oil . . . 8 Coke used for generators and boilers per 1000 cubic feet. . . . . . .48 Ibs. Oil used per 1000 cubic feet . . . . 2j gallons Total cost per 1000 cubic feet, including fuel, generating wages, purifying and labour, salaries, water, stores, wear and tear and sundries ....... Dellwik-Fleischer Water Gas is a "straight" or " blue " gas, and is non-luminous. The plant for producing it consists of a generator and scrubber. The generator is lined with fire-brick and has a thin lining of mica or slag wool to prevent radiation. There is no provision in the plant for enrichment as in the case of carburetted water gas, this being obtained by the use of a separate plant. COKE OVEN GAS. The gas from coke ovens is now being supplied for lighting and heating purposes. The Little Hulton Urban District Council (recently supplied PYROMETERS AND HEAT RECORDERS IO i with gas from Salford) now takes its supply from the coke ovens of Lord Ellesmere. The gas has an illuminating power of 16 candles tested with the Metropolitan argand burner No. 2, and a calorific value of 597 B.Th.U's., gross. (See pages 371 and 407 for an explanation of the term gross as here used.) The composition of the gas is as follows : Hydrogen . ' . . . . . . 48*8 Marsh gas ... . . . 30-9 Carbon monoxide . . . . . .6-9 Heavy hydrocarbons . . . . .3*8 Carbon dioxide . . . . . 2'i Oxygen 0-4 Nitrogen . . . . . . .7-1 PYROMETERS AND HEAT RECORDERS. The temperature of distillation can only be ascertained correctly by the aid of some form of pyrometer or heat recorder. There are many types and forms of pyrometers, but the chief are (i) thermo-electric, (2) electrical resistance, (3) optical, (4) thermo-electric radiation, and (5) calorimetric. Watkin's " heat recorders " consist of a number of fusible pellets enclosed in separate compartments in a refractory case, the pellets being standardized to fuse at different temperatures. Radiation pyrometers, of which the Fery is a type, are perhaps the most useful for gas works purposes. The latter is specially adapted for recording the temperatures of the producer, combus- tion chamber, retort, and waste gas flues. It can also be used for determining the temperatures in water gas manufacture. The Fery pyrometer is made in two types the thermo-electric radiation and the spiral. By the former, to ascertain the tempera- ture, the hot body is sighted through an eyepiece, and the radiation emitted by means of a concave mirror upon the junction of a special thermo-couple, which is arranged within the telescope and connected to a terminus fixed to the body of same. A galvanometer and length of armoured cable complete the apparatus. The galvano- meter is of the pivoted moving coil type, requires no levelling, and is an improvement on the pattern formerly used. This type of pyrometer can be used either for giving instantaneous readings or for obtaining a continuous record of , temperature. 102 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS The spiral type pyrometer is similar in principle to that of the above, but instead of the radiation being focused on a thermo- couple, it is thrown on to a flat spiral. The spiral is made of two dissimilar metals having widely different co-efficients of expansion. These are soldered together, the inner side of the spiral being made of the metal with the greater co-efficient of expansion. The spiral is fixed at its inner end on a small steel stem which is supported centrally in the telescope, while the outer end carries a light aluminium pointer, deflections of which indicate on the scale the amount of heat radiated on to it by the hot body, the scale being calibrated to read directly in degrees of temperature. This instrument is not quite so accurate as the thermo-electric type, but it has the advantage of being extremely portable and robust. The following table by Pouillet gives the colours corresponding to various high temperatures : Faint red . ... . . 977 Fahr. Dull red ...... i29o c Brilliant red .... . . . I 47o c Cherry red . . . . . 1650' Bright cherry red ..... i83O c Orange . 2Oio c Bright orange ...... 2190' White heat ...... 2370' Bright white heat . . . . . 2550' Dazzling white ..... 2730' Melting point of cast-iron White .... 1920 to 2Oio c Grey .... 2010 to The carbonizing temperature of clay retorts ranges from 20io ( Fahr. (orange) and upwards. ANALYSIS OF FURNACE GASES. With the direct-fired furnace, in which, beyond governing the consumption of fuel by the aid of dampers regulating the chimney draught, no control of the furnace is possible, an analysis of the waste gases from the furnace is of little practical value. With the adoption of gaseous firing, however, the great advantage of which rests in the means it affords of obtaining ANALYSIS OF FURNACE GASES 103 a combustion which, in theory, is approximately perfect, a full knowledge of both the producer gases and the waste gases is almost, if not wholly, synonymous with efficient working. Theoretically, the producer gas should contain 34 J per cent, of carbon monoxide and 65 J per cent, of nitrogen ; but an average analysis will generally show 25 per cent, of carbon monoxide, 60 per cent, of nitrogen, 8 per cent, of carbon dioxide, and 7 per cent, of hydrogen and methane. The waste gases should contain not more than ij per cent, of oxygen, no carbon monoxide, 21 per cent, of carbon dioxide, and 77^ per cent, of nitrogen. A wrought-iron tube is employed for collecting the sample. This is made to pro- ject into the centre of the top flue, and is continued some distance outside, so as to cool the gas. To better obtain an average sample, it is well to aspirate a much larger quantity of gas than is re- quired, '"and take off the sample simultaneously by a branch tube. There are three or four efficient apparatus for ascer- taining the composition of FlG - 59- producer and waste gases, but that of Orsat is perhaps the simplest and most compact. The Orsat apparatus (Fig. 59), and its manipulation, may briefly be described as follows : The measuring tube or burette, A, consists of an elongated bulb, terminating at the top in a capillary tube, and diminished at the bottom into a tube of uniform bore, graduated in tenths of a cubic centimetre. The tube contains from the zero mark to the upper capillary end exactly 100 c.c. at normal temperature and io 4 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS pressure To keep the burette as much as possible from the influence of sudden changes of temperature, it is provided with a water jacket. The lower end of the tube is connected by means of caout- chouc tubing with a water " level " bottle, d, which can be raised or lowered at the will of the operator. The upper capillary tube is bent at right angles with the vertical, a short distance above the measuring tube, and is continued across the apparatus on wooden supports. Other capillary tubes, provided with stopcocks, are fused into the main capillary, and are connected at their lower end by a short length of caoutchouc tubing with the U-shaped absorption vessels, B' B" B'", filled with bundles of glass tubes ; the object of the latter being to expose a large surface to the gases under test. These absorption vessels are half filled, respectively, with a solution of caustic potash, an alkaline solution of pyrogallate, and a concentrated solution of cuprous chloride in hydrochloric acid. The vessel B' will then absorb any carbon dioxide in the gas to be analysed, the vessel B" any oxygen, and the vessel B'" any carbon monoxide. It is not customary to analyse for the hydrogen and methane, though this can be done by the addition of a palladium apparatus following the vessel B"'. The nitrogen is estimated as residue. Manipulation. See that the absorption vessels nearest the main capillary tube are full to the mark in the capillary neck. This is done by opening the connecting taps and lowering the level of the water in the measuring tube, for which purpose the " level " bottle, d, is used. Then shut off the cocks. The measuring tube must then be filled with water up to the capillary part, by raising the level bottle. The outer end of the capillary tube, h, must now be connected with the tube through which the gas to be tested has to pass, and the lower end of the three-way cock, c, with an india-rubber pump, by which the air is removed from the connected tube. Now aspirate the gas by lowering the level bottle, d, and turning the tap, c, through 90. Run off the water a little below the zero mark, close the tap, c, raise the level bottle, d, so as to compress the gas and allow the excess of water to run out to zero by cautiously opening the pinch cock, m. To finish the operation, the tap, c, is CONDENSATION 105 opened for an instant to equalize the pressure, whereupon exactly 100 c.c. of gas will be confined within the burette. The gas is now ready for testing, first by the absorption of carbon dioxide by conveying the gas into the vessel B', contain- ing a solution of caustic potash. This is done by raising the level bottle, d, and opening the tap, e. The absorption is quickened by raising and lowering the level bottle two or three times, care being taken not to draw any of the reagent into the capillary tube. The level of the solution in B' is then brought up to the mark on the capillary tube, and the tap, e, closed. The read- ing can then be taken by raising the level bottle until the water in the bottle and the water in the burette are at the same level. The decrease in volume found indicates the percentage by volume (since 100 c.c. w r ere taken) of carbon dioxide. In like manner the oxygen is absorbed in B" and the carbon monoxide in B"', the unabsorbed residue representing the nitrogen and a small percentage of hydrogen and methane. Reagents. The caustic potash solution should be of i'2 to 1-28 specific gravity. The alkaline pyrogallate is prepared by adding 18 grs. of pyro- gallol to the above caustic potash solution. The cuprous chloride solution is prepared by adding 35 grs. of copper chloride to 200 c.c. of strong hydrochloric acid and a few strips of sheet copper ; this solution to be kept well stop- pered for two days and well shaken, after which add 120 c.c. of water. The vessel B'" should contain either strips of copper or copper wire, to keep the cuprous chloride up to strength. CONDENSATION. The cooling or condensing of the crude gas is an indispensable preliminary to its purification. Although the heavier tars are deposited in the hydraulic and foul mains within the retort house, there are lighter tars which continue suspended in the gas in the form of vapour, and are carried forward until a reduction in the temperature causes their deposition. Although it is commonly said that " thorough condensation is half the purification," the degree of condensation to which coal 106 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS gas should be subjected after leaving the retorts, and before enter- ing the purifiers, has never been determined with that scientific accuracy which the importance of the subject demands. With respect to one point there cannot be two opinions viz. the necessity of guarding against a lower temperature in the gas than 50 Fahr. If condensation is carried beyond this, the lighter hydrocarbons are in danger of being deposited, and the gas impoverished. The bad effects of excessive refrigeration are shown in the following table, which exhibits the loss of illuminating property in coal gas on exposure to the temperature of freezing point, 32 Fahr. : Hydrocarbons condensed from Name of Gas. 1000 Cubic Feet of Gas on Exposure to a Temperature of 32 Fahr. Boghead cannel . . . 4*42 cubic feet. Ince Hall ,, . . 0-37 Methyl . . . 0-33 From which it appears that the richest gas suffers the greatest deterioration on being subjected to cold. Experience has sufficiently proved that rapid or sudden, as well as excessive, condensation is an evil to be avoided, and that to prevent the deposition of naphthalene in the pipes, and preserve some of the richer illuminants, the gas should be allowed to travel in contact with the lighter tars until the latter are reduced in temperature to about joo Fahr. before separation takes place. With this object in view, the pipe leading from the hydraulic main may be carried with a gradual inclination round the interior of the retort house or other convenient building, and from thence to the condenser ; provision, of course, being made to allow the thicker tar to run off at a point near to the hydraulic main. By this arrangement the gas is slowly reduced in temperature, and some of its most valuable light-giving hydrocarbons, which would otherwise be condensed, are retained within it in the permanent state. Naphthalene. In dealing with the subject of condensation, that of the formation or deposition of naphthalene may be appro- priately discussed. This hydrocarbon when deposited in the solid state in the apparatus and mains of a gas-works, and in the dis- tributing pipes in the streets, is exceedingly troublesome, sometimes NAPHTHALENE 107 entirely blocking the passage of the gas, and entailing much labour and expense in its removal. It is generally believed that the presence of naphthalene in coal gas is due to two causes: first, pyrogenic synthesis, and, second, polymerization of the hydrocarbons consequent on the high heats necessarily used in the carbonization of the coal. In the early days of gas-lighting, when iron retorts were used exclusively, and the heats were comparatively low, naphthalene as now found in the mains in the solid state was almost unknown. It was not until clay retorts came to be employed, and the heat of carbonization was increased, that naphthalene made its appearance. It is well known by its flaky crystalline structure and its peculiar ethereal odour. It is not soluble in water, but easily so in naphtha ; hence its removal is effected by steaming with naphtha vapour, or by pouring that liquid into the obstructed mams and apparatus. Naphthalene is deposited most freely from gas produced from bituminous coal. Some kinds of coal yield it in greater abundance than others. By using a proportion of cannel along with the coal, the gas, being enriched, is enabled to retain some or the whole of the naphthalene in suspension within it in the gaseous condition. The richer the gas, the more capable it is (under ordinary condi- tions) of retaining the constituents which contribute to its enrichment, and vice versa. The gas should be cooled to a temperature slightly lower than, or equal to, what it will experience in the mains and services. The per- centage of naphthalene that can be retained in a gas is in proportion to its temperature and vapour tension. Gas at a high temperature will hold more naphthalene in suspension than gas at a low tempera- ture. Therefore, if gas is not properly condensed that is to say, if it is not reduced to the temperature to which it will be likely to fall in the mains and services then the excess of naphthalene held in the gas will be deposited. The experiments of M. Bremond are here recounted as being of historical interest, and also to show the philosophy underlying the facts, rather than for the purpose of recommending his remedy, which would be cumbrous in practice. In the year 1877 M. Bremond published an account of a series of valuable researches made by him on the question of the forma- tion of naphthalene and its deposition, in which he showed that (to io8 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS use his own words) " naphthalene is produced wherever there is condensation of the aqueous vapours contained in the gas ; that its deposition is preceded by the phenomenon of the condensation of the water ; and that gas absolutely deprived, as far as possible, of aqueous vapour does not deposit naphthalene under the ordinary conditions of temperature and pressure." It is clear, therefore, that the subject of condensation is one of the utmost importance, if naphthalene, or an excess of it, is to be got rid of. But however perfect the ordinary condensing apparatus may be, it is almost impossible to deprive gas of its aqueous vapour by this means. M. Bremond therefore adopted other means of drying the gas ; and for this purpose he employed an ordinary lime purifier. But instead of filling it with slaked or hydrated lime, he charged it with unslaked lime in lumps. By passing the gas through this unslaked lime he completely desiccated the gas, with the interesting result that the aqueous vapour, and consequently the excess of naphthalene also, was arrested. The gas thus deprived of its moisture was found to have increased in illu- minating power to a considerable extent. This remarkable result of drying the gas had previously been observed by the first London Gas Referees. They found that the gas made at Beckton actually gained in illuminating power in traversing the long length of mains from Beckton to London, and they remark as follows : "In considering the satisfactory result of the novel and somewhat perilous enterprise, the Referees are inclined to account for it [the increase in the illuminating power] mainly by the slow and gradual withdrawal of aqueous vapour from the gas in its long journey. This condensation is very different in character from the sudden withdrawal of aqueous vapour produced by the application of great cold ; for it takes place very gradually, so that the water is deposited without any appreciable portion of the hydrocarbons being condensed along with it. In order to ascertain the effect of withdrawing the aqueous vapour from gas, we made several experiments by passing the gas through porous calcium chloride ; the results showing that dry gas has a superiority in illuminating power over ordinary gas to the extent of from 6 to 8 per cent." Quite a number of remedies, more or less successful, have been adopted for the suspension or elimination of naphthalene. Mr. Botley has accomplished the retention of naphthalene by TAR FOG 109 carbxiretting the gas after the holders with petroleum oil in the form of mist, produced mechanically. Another method, which has proved efficient, is to vaporize carburine by means of steam, mixing it in the proportion of about 12 gallons of the oil per million cubic feet of gas passing into the holders. Various other vaporizers have been designed with a fair amount of success for the purpose of adding to the gas a quantity of the vapour of suitable hydrocarbons, with the object of giving it a greater power of retaining the naphthalene in the gaseous form (see pp. 408-10). The obvious objection to all the above is that, owing to the almost universal use of the incandescent mantle, gas of a lower illuminating power" than formerly is now generally supplied, and therefore enrichment is not required. Various other methods adopted for the removal of naphthalene are based on the known fact that it can be dissolved by various solvents. The late Mr. Alfred Colson's process consists in washing the gas in some form of washer such as the " Livesey " with an oil consisting chiefly of those distillates of coal tar which have their boiling point between 338 and 419 Fahr. Mr. Ferguson Bell washes the gas with warm tar, and afterwards with heavy naphtha ; the quantity of naphtha used being one-fifth of a gallon per ton of coal carbonized. It may be pointed out, also, that the provision of a tar extractor before the condenser has been found to give beneficial results in the reduction of naphthalene. Tar Fog. Too sudden condensation of the crude gas often results in the formation of tar fog i.e., tar is condensed in minute globules, a conglomeration of which offers a large surface in contact with the gas. When these conditions exist, the gas not only loses some of its illuminants, but a proportion of tar is carried forward to the purifiers. Different forms of apparatus for the removal of tar fog have been devised in which the principles employed are the division of the gas into numerous small streams, or its subjection to friction or impingement. Dr. Colman applies the principle of centrifugal force at the inlet of the condensers. no NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS His apparatus consists of a wrought or cast iron cylinder under which there is an inverted conical portion, the lower end being attached to a syphon for the removal of the liquids that are separ- ated in the apparatus. The gas enters at a tangent, and sets up a whirling motion of the whole contents of the separator. Under the influence of this force the solid and liquid particles are driven to its circumference, where they coalesce and fall down the sides, being conveyed away by the syphon. The Pelouze and Audouin condenser (see p. 119) is also used both as a tar extractor and tar fog eliminator. Everitt's extractor is a modification of the latter, and consists of a horizontal iron vessel containing a series of screens of iron wire gauze. The screens are fixed vertically and about J- inch apart by means of metal separating rings at their circumference. Between the screens, exhaust steam is intermittently injected in such a manner as to cause the precipitation of the tarry matter and the breaking up of the vesicles, thus liberating their contained gases. Crossley's patent centrifugal tar extractor is also an efficient apparatus for the removal of tar fog. A slow cooling of the gas, however, by the aid of a back main and long foul main, will alleviate and often entirely prevent the formation of tar fog. Tar Fog in Water Gas. The elimination of tar and tar fog from water gas is much more difficult than from coal gas. The application of centrifugal force is the only method by which success may be obtained. Crossley Brothers, as above mentioned, have invented a tar extractor of the centrifugal type. It consists of a revolving fan or disc in a casing. -The gas enters at the centre and is .driven at a .high speed against the periphery of the extractor, with the result that the minute tarry particles coalesce and condense. About one gallon of water per 1000 cub. ft. is introduced with the gas, and this being whirled at a high speed against the periphery of the fan effects the removal of 96 per cent, of the tar. A special arrangement of symmetrical blading causes the gas to enter and leave the extractor at the same pressure. A minimum of power only is thus required to drive the fan. Temperature and Station Meter Registration. The make of gas, as indicated by the station meter, is materially affected by the temperature at which it is registered . CONDENSATION in At the temperature of 60 Fahr., with the barometer at 30 in., gas is at its standard volume : and as all aeriform bodies expand of their bulk at 32 Fahr. for every additional degree of tem- 491-4 perature, or about I per cent, for 5, it follows that a quantity of gas, say 10,000 cub. ft., registered at 60, would at 70 become 10,203-5, and at 80 10,407. The quantity of heat which will raise a cubic foot of water one degree, will raise 2850 cub. ft. of gas or atmospheric air to the same extent. TABLE. EXPANSION OF AIR AND PERMANENT GASES BY HEAT. Temp. Fahr. Expansion. Temp. Fahr. Expansion. Temp. Fahr. Expansion. . Expansion. Deg. Deg. Deg. Deg. 32 1000 52 1040-700 72 1081-400 92 1122-100 -33 1002-035 53 1042-735 73 1083-435 93 1124-135 34 1 004' 070 54 1044-770 74 1085-470 94 1126*170 35 1 006' 105 55 1046-805 75 1087-505 95 1128-205 36 1 008-140 56 1048-840 76 1089-540 96 1130-240 37 1010-175 57 1050-875 77 1091-575 97 1132-275 38 IOI2'2IO 58 1052-910 78 1093*610 98 1134-310 39 1014-245 59 1054-945 79 1095-645 99 1136-345 40 1016-280 i 60 1056-980 80 1097-680 100 1138-380 41 1018-315 61 1059-015 Si 1099-715 no 1158-730 42 io2O'35o 62 1061-050 82 1101-750 120 1179-080 43 1022-385 63 1063-085 83 1103-785 130 1199-430 44 1024-420 64 1065-120 84 1105-820 140 1219-780 45 1026-455 65 1067-155 85 1107-855 150 1240-130 46 1028*490 ! 66 1069-190 86 1109-890 1 60 1260-480 47 1030-525 67 1071-225 87 1111-925 170 1280-830 48 1032*560 68 1073*260 88 1113-960 180 1301-180 49 1034-595 69 1075-295 89 1115-995 190 1321-530 50 1036-630 70 1077-330 90 III8-030 200 1341-880 5i 1038*665 ! 7I 1079-365 9i II20-065 212 1366-300 In instituting a comparison between the production per ton of material at different works, and in testing the productive value of different coals, it is therefore necessary to take into account the temperature of the gas at the time of measurement. In ascertaining the specific gravity of gas, and in conducting photometrical observations, the same care should be taken to note the temperature at the time and place of making the experiment. H2 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS TABLE. Giving the Mean Temperature (Fahr.) of every Tenth Day in the Year in the Central District of England. (Box.} Month. ISt. nth. 2ISt. Month. Deg. Deg. Deg. January February 36-5 37'2 35-6 37'5 37" i 38-5 July - August March . 40-1 41*0 41-9 September April . 43'6 45 - o 47-0 October May 50-0 5i'3 53-8 November June 56-4 57'5 59'8 December ISt. nth. 2ISt. Deg. Deg. Deg. 6l'2 6i'5 62'O 62-5 61-7 60-6 58-8 57'4 55'5 53'5 5i'4 49-0 46-4 44' o 42-0 4r7 40-2 38-4 Condensers. The Atmospherical horizontal condenser (Fig. 60) is one of the earliest forms of the apparatus. Its efficiency has not been generally recognized, owing to the want of a correct appreciation of the conditions on which the condensation of coal gas ought to be conducted, and this has led to its being generally discarded in favour of the vertical form. The earlier method of construction was to fix it against the CONDENSERS 113 outside of the wall of a retort house or other convenient building ; the several pipes rising with a slight inclination one above the other to allow of the flow of the condensed products, their ends being connected by D -shaped bends. Graham's condenser (Fig. 61) is an improvement on this. It consists of a series of pipes arranged in pairs, side by side, and supported on framework, the end of each length being joined to that of the next. From the inlet at the top, through the entire run of the condenser to the outlet at the bottom, there is a gradual inclination, so that it is simply a flat screw or spiral, such as might be represented by winding a length of soft wire round a piece of board, in which case the two ends of the wire would answer to the FIG. 61. inlet and outlet of the condenser. Blank flanges are bolted on the end of each length for convenience in cleansing; In this arrangement there is a recognition of the fact that length rather than height is the desideratum in an atmospherical condenser. In the ordinary vertical form of the apparatus, the cooling effect of the air on the surface of the upper parts of the pipes is almost nil. This will be obvious when it is con- sidered that the air contiguous to the lower part of the condenser, being assimilated to the temperature of the latter, expands, and so, becoming lighter than the surrounding air, ascends in contact with the pipes, extracting less heat in proportion as it rises. In addition to the other advantages, the ammoniacal liquor on leaving the horizontal condenser is of a strength equal to 5 Twaddell I NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS result which it is impossible to obtain from the ordinary vertical form. The ordinary atmospherical condenser (Fig. 62) consists of a series of pipes, usually 18 ft. long, put together in two lengths, and placed upright, through which the gas passes up and down alternately. These enter a rectangular cistern at bottom, in which the condensed vapours are deposited, and from whence they flow to the tar well. At the top is another cistern, containing water to seal the movable hoods covering each pair of pipes ; and for further refrigeration, should such be required, in warm or sunny to trickle down the exterior FIG. 62. to be an improvement weather, small streams are made surface of the pipes. The annular condenser is considered on the foregoing. In Kirk- ham's condenser, as im- proved by Wright (Fig. 63), the pipes are placed in the vertical position, and are of large diameter, each one enclosing a smaller pipe ; the two forming an annular space through which the gas is made to flow. Other pipes, placed diagonally, con- nect the top and bottom of the condensing columns al- ternately. By this arrange- ment the gas passes through the annular space always in the downward direction, whilst the current of air moves upward through the interior ventilating pipe. In cold weather movable CONDENSERS covers are placed over the latter, or butterfly valves are fixed at the foot, for closing, to regulate the air draught, which might otherwise reduce the temperature of the gas below the desired standard. A small pipe is connected to the bottom of each column to carry away the deposited tar and water into a main laid alongside the condenser and leading into the tar well. The annular atmospheric condenser (Fig. 64) is a modification of the latter, and is the one most generally adopted. The gas travels by way of the annular space through the two columns ; but, FIG. 64. instead of the columns being connected diagonally, they are connected to each other alternatively top and bottom by means of cast-iron flanged branches riveted to the outer columns. . The inner tube or cylinder in each column is open to the atmosphere throughout its length, and an air slide or butterfly valve fixed at the base acts as a controller of the air passing up the column. At the base of each outer tube a cast-iron pipe is fixed so as to remove the products of condensation which are conveyed into the syphon pot. Cleland's slow-speed condenser consists of a series of vertical pipes, connected together at the top by a tubular cornice or cap, which serves as the common inlet to the whole series. The stream of gas, being thus divided equally amongst the several columns, I 2 U6 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS travels through them in a downward direction and at a compara- tively slow speed. In the lower part of each column, to about a fifth part of its length, is inserted a " bottle brush " of wood or other material, with a drip-ledge above it to divert the descending liquor on to the centre of the brush, which has the effect of converting the apparatus, to that extent, into a scrubber. The general result is superior efficiency in condensing and the yield of a high strength of liquor. An excellent apparatus (atmospherical) is that known as the battery condenser (Fig. 65). This is an oblong vessel, 12 to 000 000 poo 000 FIG. 65. 24 in. wide, 12 to 18 ft. in height, and of length suitable to the requirements of the works. It is divided by internal plates or mid-feathers (placed at distances, equal to the width, apart), extending to within a few inches of the top and bottom of the chest alternately ; and the gas passes from the inlet, up and down each division, till it arrives at the outlet. To augment its condensing power, small tubes, 2 in. in diameter, through which the air has free circulation, are passed through from side to side of the vessel and there securely jointed. These transverse tubes serve the double purpose of cooling the gas and, by breaking it up and retarding its progress, inducing a natural settlement of the heavy condensable vapours. It may be taken as a general rule that about 10 superficial ft. of atmospherical condensing surface for each 1000 cub. ft. maximum CONDENSERS 117 gas production per day of 24 hours should be provided. This includes the length of foul main extending from the hydraulic main. Moreover, the condenser should be protected from the direct action of the sun's rays ; or, otherwise, water should be made to trickle down the outer surface of the pipes during sunshine. Sir George Livesey, in some of his condensing arrangements, adopted a plan of placing the condensing pipes in a tank divided into channels, through which water is made to flow, and which can be regulated according to the make of gas. The water enters the tank at the point where the condensed gas makes its exit, and, flowing in the opposite direction to the gas in the pipes, is gradually raised in temperature by the latter till it reaches its outlet where the crude gas enters. Thus a more uniform condensation is obtained than is possible in the atmosphere. In this connection the following table by Peclet, showing the relative effects of water and air as cooling agents, is interesting and useful : Quantity of Heat lost by a Square Unit Excess of Temperature of Exterior Pipe Surface. over For an excess of 10 . . . 8 . 88 20 . . .18. . 266 30 ... 29 . . 5,353 40 4 8 >944 50 . 53 . . 13,437 Water is thus shown to be the superior cooling agent, re- quiring the exposure of much less radiating surface than air ; but, for the reasons already adduced, the temperature of the water must be regulated in order to avoid any sudden condensation. An apparatus that is being rather widely adopted is the water tube condenser. This is made in different forms, the principle of each being the same. It is constructed either of ordinary pipes having small tubes passing through their interior, or of cylindrical or square chambers filled with such tubes, and placed either hori- zontally or vertically, the latter by preference. Through the tubes a stream of water is made to flow in the opposite direction to that of the gas which surrounds them, so that by the time the water reaches the inlet of the condenser it has, by absorbing the heat n8 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS t of the gas, attained a comparatively high temperature, and thus any sudden cooling of the gas at the entrance is avoided. The ease with which the cooling power of the apparatus can be varied and controlled, by increasing or diminishing the flow of the water, is a strong recommendation in its favour. There are advantages to be gained by having the condenser reversible. By occasionally reversing the flow of gas and water, obstruction in the condenser is minimized. The underground condenser is so called because the pipes are placed in the ground, out of reach of the fluctuations of temperature in the atmosphere, with a view to obtaining uniformity of action in the process of condensation. By this system, however, a much longer length of piping is required than by any other, owing to the small amount of radiation from the surface of the buried pipes. There is an advantage in this process of gradual condensation ; but it is advisable, wherever in use, to supplement it by finally passing the gas through one of the other forms of condensers having less than the usual area. In some works condensation is effected by means of dry scrubbers cast-iron vessels of large diameter charged with coke, drain tiles, or other material, breaking up the gas into very minute streams, which, being thus cooled, deposits its tar and water. A natural settlement of the condensable matter also takes place irrespective of the action of the contained material, owing to the velocity of the flow of the gas being reduced on entering the larger area. The rapid fouling of these vessels, however, necessitating frequent changing of the filling material to prevent undue back pressure and maintain their efficiency, renders their use objectionable. Precipitating chambers of large size are also employed, without any filling material, in which the gas sleeps, as it were, and deposits its condensable particles. The large volume of gas also serves as a cushion to counteract pulsatory action between the exhauster and the retorts. But it is a dangerous piece of appar- atus, and we do not recommend its adoption. On a works being restarted after being temporarily shut down from any cause, the mains and this large chamber are liable to become charged with an explosive mixture of air and gas ; and in the event of any of the dip-pipes in the hydraulic being unsealed, the CONDENSERS 119 mixture is likely to be fired, with the inevitable explosion as the result. A recent serious accident at a gas-works was due to this cause. The principle of Pelouze and Audouin's condenser differs from that of any of the other apparatus described. In construction it consists of an outer cylindrical cast-iron chamber, with the usual inlet for gas, and outlets for gas and liquids, and contains a cylinder of perforated sheet-iron constituting the condenser. The sides of the condensing chamber are two thin sheets of iron with a concentric space between. The inner sheet is perforated with holes ^V of an inch in diameter, and the outer with slots of large size ; the outer sheet being so arranged as to offer a blank surface opposite the small holes in the inner sheet. The gas and condensable vapours pass through the small perforations, the vapours being as it were wire-drawn, and striking against the opposite solid surface are deposited thereon, and flow down into the receptacle below, and thence to the tar well. The gas passes on through the slots hi the outer cylinder to the outlet pipe. The condensing cylinder is so balanced as to rise and fall in an annular space containing tar or liquor which acts as a seal. As the make of gas increases or decreases, the cylinder rises or falls, and consequently a larger or less number of openings are un- covered for the passage of the gas. The result is a more complete separation of the tar from the gas than is attainable by any other form of condenser. It has been attempted, though with doubtful success, to con- dense and carburet the gas -at one and the same time. The Aitken and Young analyser, and the St. John and Rockwell apparatus, were each designed by their inventors to enrich the gas by carburation. The tar and gas were both conveyed direct from the hydraulic main to the apparatus, their temperature at the inlet being maintained as high as possible. Means were even adopted of raising the temperature if required, in order that the heavier hydrocarbons present in the crude gas and tar might be permanently suspended, and so become fixed illuminants in the gas, notwithstanding the subsequent reduction of temperature in the ordinary course of purification. Great hopes of the process were at one tune entertained, but it failed to meet the expectations of the inventors. 120 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS In connection with the subject of condensation, the following table, comparing the English and foreign thermometers, will be found useful : Fahr. Reau. Cent. Fahr. Reau. Cent. Fahr. Reau. Cent. Fahr. Reau. Cent. I 212 80-0 lOO'O 160 i 56-8 71-1 108 33'7 42-2 56 io'6 i3'3 211 79' 5 99'4 159 56-4 70-5 i 107 33'3 4 r6 55 IO'2 12-7 210 79'i 98-8 158 56-0 70-0 1 06 32-8 41-1 54 9'7 I2'2 209 78-6 98-3 157 55'5 69-4 105 32-4 40-5 53 9' 3 ir6 208 78-2 97'7 i 156 55'i 68-8 104 32-0 40' o 52 8-8 II'I 207 77'7 97'2 155 54-6 68-3 103 3i'5 39'4 5i 8-4 I0'5 206 77'3 96-6 154 54' 2 67-7 102 3i'i 38-8 50 8-0 IO'O 205 76-8 96-1 153 53'7 67-2 j 101 30-6 38-3 49 T 5 9'4 2O4 76-4 95'5 i 152 53'3 66-6 100 30-2 57'7 48 7-i 8-8 203 76-0 95'o 151 52-8 66-1 99 29-7 37'2 47 6-6 8-3 202 75'5 94'4 150 52-4 65-5 98 29'3 36-6 46 6-2 7'7 201 75 i 938 149 520 65-0 97 28-8 36-1 45 5'7 r 2 200 74-6 93'3 148 5i' 5 64-4 96 28-4 35'5 44 5'3 6-6 199 74'2 92-7 147 5i'i 63-8 95 28-0 35'o 43 4-8 6-1 198 73'7 92-2 146 50*6 63-3 94 27'5 34'4 42 4' 4 5'5 197 73-3 91*6 145 50-2 62-7 93 27'i 33-8 41 4-0 5'0 I 9 6 72-8 91-1 144 49' 7 62-2 92 26-6 33'3 40 3'5 44 195 72-4 90-5 143 49'3 6r6 QI 26-2 32-7 39 3" i 3'8 194 72-0 90'o 142 48-8 6ri 90 257 32-2 38 2-6 3'3 193 7i'5 89*4 141 48-4 60-5 89 25' 3 3r6 37 2'2 2'7 192 71-1 88-8 I 140 48-0 6o'O 88 24-8 3i'i 36 1*7 2' 2 191 70-6 S8-3 ! 139 47'5 59'4 87 24-4 30-5 35 13 1-6 190 70-2 87-7 138 47" i 58-8 86 24'0 30-0 34 0-8 ri 189 69-7 87-2 : 137 46-6 58-3 85 23'5 29-4 33 0-4 0-5 188 69-3 86-6 136 46-2 57'7 84 23' i 28-8 32 - O'O 187 68-8 86-1 135 45' 7 57-2 83 22-6 28-3 31 0-4 0-5 186 68-4 85-5 134 45'3 56-6 82 22'2 27-7 30 0-8 ri 185 68-0 85-0 133 44-8 56-1 81 21'7 27'2 29 i'3 1-6 184 67-5 84-4 132 44'4 55'5 80 21'3 26-6 28 i'7 2'2 183 67-1 83-8 131 44' o 55'0 i 79 20-8 26-1 27 2'2 2'7 182 66-6 83-3 130 43-5 54'4 78 20-4 25' 5 26 2'6 181 66-2 82-7 129 43'i 53-8 77 20'0 25-0 25 3'i 3' 8 1 80 65-7 82-2 128 42-6 53'3 76 I9'5 24-4 24 3'5 4'4 179 65-3 8r6 127 42'2 52-7 75 19-1 23-8 23 4-0 5'0 178 64-8 8ri 126 41-7 52-2 74 18-6 23'3 22 4'4 5'5 177 64-4 80-5 125 4I-3 5i-6 73 18-2 22'7 21 4-8 6'i T 7 6 64-0 80-0 124 40-8 5i'i 72 i7'7 22*2 20 5'3 6-6 175 63-5 79'4 123 40-4 50-5 7i I7'3 2r6 19 5'7 7'2 174 63-1 78-8 122 40-0 50-0 70 16-8 2I'I 18 6-2 7'7 173 62-6 78-3 121 39'5 49'4 69 16-4 20'5 17 6'6 8-3 172 6 2 -2 77' 7 120 39' i 48-8 68 i6'o 20'0 16 7'i 8-8 171 61-7 77'2 119 38-6 48-3 67 I5'5 19-4 15 7'5 9'4 170 61-3 76-6 118 38-2 47'7 66 i5'i 18-8 14 8-0 10'0 169 60-8 76-i 1 H7 37'7 47'2 65 I4'6 18-3 13 8-4 10-5 168 60-4 75'5 1 116 37'3 46-6 64 14-2 I7'7 12 8-8 n'i 167 60-0 75'o ; H5 36-8 46-1 63 I3'7 I7'2 II 9'3 ir6 166 59-5 74'4 114 36-4 45-5 62 I3'3 16-6 10 9'7 12'2 165 59-i 73'8 "3 36-0 45'0 61 12-8 16-1 9 IO'2 12-7 164 58-6 73*3 ! 112 35' 5 44'4 60 I2'4 I5'5 8 io'6 -13-3 163 58-2 72'7 III 35' i 43-8 59 12' I5'o 7 in 13-8 162 57-7 72-2 i no 34-6 43' 3 58 "'5 14-4 6 n'5 14-4 161 57'3 I 7i 6 109 34'2 42-7 57 in 13-8 5 12'0 I5-0 THERMOMETERS 121 To convert Degrees of Fahrenheit into those of Centigrade and Reaumur, and conversely. To convert Fahr. into Cent. RULE ist. Subtract 32, and divide the remainder by i'8, thus: Fahr. 167 = Cent. Orby RULE 2nd. Subtract 32, multiply the remainder by 5, and divide the product by 9, thus : , - Fahr. (167-33) X5 =75Cent To convert Cent, into Fahr. RULE ist. Multiply by r8, and add 32, thus : Cent. 75 x r8 + 32 = 167 Fahr. Orby RULE 2nd. Multiply by 9, divide by 5, and add 32, thus : Cent. 75 X 9 + ^ = l6 Fahr 5 To convert Fahr. into Reau. RULE ist. Subtract 32, and divide by 2-25, thus : Fahr. 113 32 AT?' 2-25 Orby RULE 2nd. Subtract 32, multiply by 4, and divide by 9, thus : 9 To convert Reau. into Fahr. RULE ist. Multiply by 2-25, and add 32, thus : Reau. 36 x 2-25 -f 32 = 113 Fahr. Orby RULE 2nd. Multiply by 9, divide by 4, and add 32, thus : Reau. 36 x 9 + 32 = 113 Fahr. 122 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Drory's Main Thermometer. The illustrations, Figs. 66 and 67, show the improved arrangement invented by Dr. Drory for ascertaining the temperature of the gas passing through the condenser and other apparatus and the mains. It consists of an outer shell fitted with a conical hollow plug having an aperture corresponding to that in the outer shell. The tester which fits FIG. 66. FIG. 67. into the plug contains a thermometer, which on being turned opposite to the apertures is hi immediate contact with the gas, and on withdrawal the temperature is ascertained. For attaching the tester, a hole suitable for a i-in. wrought-iron pipe is drilled and tapped in the pipe or side of the apparatus, and the instrument is screwed therein. THE EXHAUSTER. The exhauster is best placed to follow the condenser. The raison d'etre of this apparatus, which is really nothing more nor less than a pump, is to relieve the retorts of the pressure caused by the obstruction offered to the gas in its passage through the washers, scrubbers, purifiers, and station meter into the holders. Exhausters are now made of almost any size, down to the smallest ; and there are but few gas-works, however small, where they cannot be applied with advantage. The invariable result of the use of the exhauster is to increase the production per ton, to improve the quality of the gas (provided air is not drawn in), and to lengthen the duration of the retorts, by preventing, in a EXHAUSTERS 123 great measure, the deposition of carbon the removal of which with the ordinary chisel bars is so destructive and unsatisfactory. Mechanical exhausters are of two kinds : the rotary and the reciprocating. Both descriptions have their advocates, and much may be said in favour of each. Beale's exhauster was the first one constructed on the rotary principle. Its early form is shown in Fig. 68. Its parts consist of a cylinder, inside which a drum revolves, and is provided with pistons or slides which have a radial motion. The drum is smaller in diameter than the inside of the cylinder, and the centre lines or axes of both are parallel and horizontal. But the drum is placed eccentrically in the cylinder, so as to be in contact with it at the bottom, without resting on it. The inlet and outlet passages are on the two opposite sides of the cylinder, FlG 68 and as the slides are guided by seg- ments in the end plates, so that their outer ends are always in contact with the inside of the cylinder, the gas enters one side, is carried round over the drum to the other side, and is forced out at the outlet. This form of exhauster is the one now most generally adopted, and whilst the original type is retained, important modifications and improvements have been effected in its construction and action by various makers of recent years notably by Gwynne & Co., Bryan Donkin & Co., W. H. Allen & Co., and George Waller & Son. The illustrations (Fig. 69) show sections of a Beale's exhauster as made by Gwynne & Co., under their patents, and containing several improvements on the machine as first invented, by which the areas of wearing surfaces have been augmented so as to greatly increase the durability of the machine. These include the double slides, large segments, steel pins fastened in the segments and extending through the whole length of the slides, and the outside bearings for the axle. In order to prevent oscillation and to reduce friction to a minimum, exhausters with three and four blades have been devised, and are a great improvement on the two-bladed form, 124 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Fig. 70 shows a section of Waller's three-blade exhauster which is suitable for works with a daily production up to half a million cubic feet. FIG. 69. Above this production per diem the four-blade exhauster (Fig. 71) is preferable. The delivery is divided into four parts, instead of two or three, thus giving a steadier gauge. The exhausters can be run in either direction, using either branch pipe as the inlet or outlet But the direction for running is always from the inlet. The blades of all these exhausters turn on a centre spindle and are radial with the cylinder, which is a true circle. FIG. 70. FIG. 71. Anderson's exhauster, which may be taken as the type of the reciprocating form of the apparatus, is shown in Fig. 72. This works in the vertical position, but others, like Dempster's, have the engine and pumps placed horizontally. The rotary exhauster may be driven either by a strap from a line shaft actuated by a steam or gas engine, or by an engine EXHAUSTERS 125 coupled direct. The reciprocating exhauster is always driven directly by the engine. By employing two of these latter exhausters, and working them from one engine, the slides of the exhausters being placed at right angles to each other, a perfectly steady vacuum and pressure are maintained. The essential features of a good exhauster are that it should be simple, and work with a minimum of friction and power ; that it should give the steadiest possible flow of gas ; and that the parts FIG. 72. should be perfectly gas-tight. The commonest fault is want oi tightness ; and when it is remembered that, under a pressure equal to a 14-in. column of water, about 9000 cub. ft. of gas will pass per hour through an opening of only one square inch in area, the absolute necessity of the best workmanship only being used in exhausters will be evident. Crude creosote oil is the best lubricant for the cylinder and slides of an exhauster when the surfaces become " pitched " with tar. 126 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS The steam-jet exhauster (Fig. 73), invented by Mr. Cleland and improved by Korting Brothers, is another form of exhaust- ing apparatus. This operates by projecting a jet of steam, at about 45 Ibs. pressure, through an arrangement of pipes or nozzles, without the intervention of any other mechanical appliances the steam being afterwards extracted by condensation. The capacity of the exhauster is regulated by the adjustable screw and spindle at the end, and by a movable inner sleeve opening or closing the port-holes by means of the screw and nut at the side. When an exhauster is employed, it is necessary to supplement its use by a gas governor, acting either on a throttle valve within the steam feed-pipe, in this case increasing or diminishing the speed of the engine, or on a valve within a by- pass connected to the inlet and outlet mains leading to and from the exhauster, the opening of which, when the exhaust is too active, allows a portion of the gas to return through the exhauster, and thus prevents the formation of a partial vacuum in the retorts. Steam Engines and Boilers. These should be provided of ample size, allowing a margin over and above the actual power needed. An engine and boiler barely fitted to do the work re- quired of them are a nuisance. The engine, besides turning the exhauster, may be used in pumping F water and tar ; and the boiler, in addi- tion to supplying steam for the engine, is useful for steaming the mains and apparatus on the works. Duplicate boilers of the required size should be provided, to allow for periodical cleaning and examination. For firing the boiler, breeze may be used, mixed with a portion STEAM ENGINES AND BOILERS 127 of coke or coal. Or if, instead of the chimney draught, a forced draught is employed, breeze and much of the furnace refuse will serve as fuel. One pound weight of coal of average quality requires for its perfect combustion 150 cub. ft. of air. In actual practice, however, about double this quantity of air passes through the furnaces of steam boilers. Wherever practicable and convenient, the boiler may be set in such a position as to allow of its being heated with the waste heat from the retort stack. In small works, if a steam boiler cannot be employed for want of space, or should a boiler be considered objectionable on other grounds, the exhauster can be driven by a gas engine. The boiler most suitable for a gas-works of moderate size is the Cornish type, with flat ends and single internal tube contain- ing the furnace. For large works, the Lancashire or double-flued boiler is best adapted. The nominal horse power of a boiler is found by multiplying the sum of the diameters of the outer shell and internal flue by the length, and dividing the product by 6. EXAMPLE. Required the power of a Cornish boiler, whose dia- meter is 4 ft. 6 in., diameter of tube 2 ft. 6 in., and length 12 ft. (4' 6" + 2' 6") X i2' f~ - = 14-horse power. Again Required the power of a Cornish boiler whose diameter is 6 ft., diameter of tube 3 ft., and length 20 ft. (6' + a') x 20' ~-~ - = 30-horse power. Again ' Required the power of a Lancashire boiler whose diameter is 7 ft., diameter of tubes 2 ft. 9 in., and length 24 ft. (7' o"+ 2' 9" + 2' 9") X2 4 ' L = 5o-horse power. In high-pressure or non-condensing engines, with Steam at 25 Ibs. per sq. in., 13-6 circular inches on piston = i-horse power. 30 Ibs. 11-3 n M = The diameter of the piston in inches squared = circular inches. 128 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS The following table gives the diameter of cylinders for high pressure (non-condensing) steam engines, from 3 to 16 horse power, with steam at 25 Ibs. and 30 Ibs. per square inch, respectively, and the length of stroke for the different sizes : Nominal Horse Power. Diameter of Cylinder in Inches. Length of Stroke. Nominal Horse Power. Diameter of Cylinder in Inches. Length of Stroke. Steam per Sq. In. Steam per Sq. In. 25 Ibs. 30 Ibs. Inches. 25 Ibs. 30 Ibs. Inches. 3 6 6 12 8 ioi 9 \ 20 H 6; 12 8* 10 9 I 20 4 7^ 14 9 n^ 10 22 4& 73 14 10 113 10 22 5 8 ft 16 ii 12; ii 24 81 7 16 12 12^ ii 24 6 9 18 13 13; 12 26 6 8| 18 14 12 26 7 9 18 15 14* 13 28 7i 9i 20 16 15 I3i t 30 The foregoing are the rough and ready methods of estimating the dimensions and power of boilers and engines. The more scientific methods of determining the proportions of engine and boiler appropriate for any particular case are most conveniently based on the actual power required from the engine, and the amount of steam required to produce that power. An engine of the plain slide-valve, single-cylinder, non-con- densing type is generally preferred for gas-works, and steam supplied at a boiler pressure of about 60 Ibs. per square inch above the atmosphere. If the engine is arranged to cut off at half stroke, it will require to be supplied with about 50 Ibs. of steam per indicated horse power per hour. An earlier cut-off is not practicable in this type of engine. Engines of other types will consume much less steam per horse power, but at a greater outlay in capital, cost of maintenance, and more liability to stoppage by derangement. Engines of higher class are however often worthy of serious attention, on account of the reduction of fuel cost which is thereby effected. The long hours of working in a gas-works, as compared with those of an ordinary manufactory, invest this point with a special degree of importance. The ratings of engines given in the tables on p. 130 are stated STEAM ENGINES AND BOILERS 129 in indicated horse power, which is the most convenient standard for definite test especially as all engines should be frequently indicated in order to verify adjustment of valves and general conditions. The ratings in the first table should be regarded as the maxima and not subject to any appreciable increase. Where a suitable supply of water is available, a steam condenser may be applied, by which means any of the engines given in the first table will drive a load of about 33 per cent, greater than is shown, or at a reduction of 25 per cent, in the steam consumed per indicated horse power per hour. The second table of compound condensing engines of a high class shows a much more economical use of steam, especially when a high pressure is adopted. Here the engine will stand an overload of 40 per cent, with 80 Ibs. steam pressure, or 80 per cent, with steam at 160 Ibs. pressure. In each case the diameter of each high-pressure cylinder is stated as half the diameter of the low-pressure cylinder. The high-pressure cylinder may however vary considerably hi diameter more especially if steam of low pressure is employed. The next tables are given for Cornish and Lancashire boilers respectively. In each case the boiler is assumed to be fired with good coal at the rate of about 18 Ibs. per sq. ft. of grate per hour. Assuming that coke, breeze, or an inferior coal is used, then larger grates are required and a correspondingly larger boiler. Forced draught is sometimes used, either to relieve an over- loaded boiler or to facilitate the use of an inferior fuel. This is best effected by means of a fan or by steam jets. In case of either of these being applied, the quantity of steam required for operating them should not be overlooked. In high-class plants for large powers, coal is burnt at the rate of from 20 to 25 Ibs. per square foot of grate per hour. In connection with the non-condensing engines, the feed water is assumed to be heated by the exhaust steam from the engine, and the rate of evaporation to be 6*5 Ibs. of steam produced per Ib. of coal burnt. Where the plant is suificiently large, and the water is not very hard, an economizer may be adopted for heating the feed water by means of the waste gases from the boilers, and the rate of evaporation thereby increased about 10 per cent. An economizer is, however, seldom applied in connection with boilers for supplying steam to non-condensing engines. K 130 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Steam Engines. STEAM ENGINES. SIMPLE, NON-CONDENSING. Indicated Horse Power. Cylinder Diameter. Stroke. Revolutions per Minute. Steam Required. Inches. Inches. Lbs. per hour. 10 6 12 200 500 20 8 16 150 IOOO 30 10 20 I2O 1500 40 i 22 110 2000 50 13 24 IOO 2500 STEAM ENGINES. COMPOUND, CONDENSING. Indicated Horse Power. Cylinder Diameter. Revolu- Steam Required. Lbs. per Hour. Stroke. tions per Minute. 80 Ibs. Steam. 1 60 Ibs. Steam. H.P. L.P. At 80 Ibs. Pressure. At 1 60 Ibs. Pressure. . Ins. Ins. Inches. @i5'5lbs. @ i2'o Ibs. 77 IOO 10 20 30 80 1200 I2OO 145 1 88 1Z\ 25 36 80 2250 2250 244 15 30 42 80 3800 3800 379 493 35 48 80 6000 6000 556 724 20 40 54 80 8600 8600 Boilers. CORNISF Diameter of Tube. t BOILERS. Steam Produced. Diameter of Shell. Length. Heating Surface. Grate Surface. Lbs. per hour. 500 IOOO 1500 2OOO 25OO Ft. Ins. 4 o 4 6 5 o 6 o 7 o Ft. Ins. 2 2 2 4 2 7 3 o 3 5 Feet. 10 14 20 24 26 Sq. Ft. 140 215 480 620 Sq. Ft. 5 8 3 21 LANCASHIRE BOILERS. Steam Produced. Diameter of Shell. Diameter of Tubes. Length. Heating Surface. Grate Surface. Lbs. per hour. 2750 35oo 4500 5000 Ft. Ins. 7 o 7 6 8 o 8 6 Ft. Ins. 2 9 3 o 3 2 3 5 Feet. 22 26 30 30 Sq. Ft. 630 820 IOOO IIOO Sq. Ft. 23* 3o| 39 42 WASHERS 131 Cement for Stopping Leaks in Boilers. Powdered fire-clay . . ., " . . 6 parts by weight. Fine iron filings . . f . . i part Made into a paste with boiled linseed oil. Cement for Metallic Joints. Equal weights of red and white lead, mixed with boiled linseed oil to the consistency of putty. THE WASHER. The washer was one of the very earliest appliances used in the purification of coal gas, and naturally so, owing to the cooling and condensing property of water and its power of absorbing ammonia and of arresting the tar. Its construction, however, was often faulty at first, and the limits of its functions misunder- stood ; so that the misuse, or overuse, of the apparatus (resulting in the reduced illuminating power of the gas exposed to its action) caused it to fall for a time into disrepute. The principle of its action is that of causing the gas to pass in finely divided streams through a body of water contained in a vessel, so that a portion of the ammonia and other gaseous impurities, and the whole of the floating particles of tar which^ have escaped condensation, may be removed before the gas enters the scrubbers. However ample the usual condensing appliances may be, some of the lightest tar vapours escape their action. These are arrested in the washer, or tar-extractor, as it is sometimes called. This apparatus should always be used in conjunction with the scrubber, and the gas passed through it in the first instance. It is generally employed as a separate and distinct apparatus, but sometimes it is placed at the bottom of the tower scrubber, of which it constitutes a part. When the washer is exposed to outside atmospheric influence, it is necessary in winter to employ means to prevent the water from falling below a temperature of 50 Fahr. ; otherwise the gas, especially a rich gas, passing through it will suffer deterioration. All washers give an amount of back-pressure, varying from K 2 132 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS i in. to 4 in., according to the depth of water traversed. There are numerous designs of the apparatus, but the principal ones are here described. Anderson's washer consists of a cast-iron outer vessel, containing a number of trays, having on their under side a series of serrated bars extending from side to side. These dip into the water or liquor, and the gas in passing through the serrations is divided into minute globules. The pressure given can be regulated by raising or lowering the overflow with which the apparatus is provided. A four-way valve is used for shut-off and by-pass. Weak ammoniacal liquor from the condenser is run in at the top, and drips from tray to tray till it reaches the bottom. The washer is made either single or double as required. In Cathels' washer the usual oblong or square vessel is divided into sections, as many as may be desired, each elevated higher than the others in the form of steps. The gas enters at the bottom, passes in divided streams through a number of curtain serrations extending the full length of the vessel, and so on through the rest, and out at the top of the higher compartment. When the liquor in the lowest section is of the strength required, it is run off, and the contents of the several sections transferred one step lower, the last or uppermost being charged with fresh water. This apparatus is also arranged in the vertical position, to occupy less ground space. Livesey's washer is a compact and efficient apparatus, occupying less room for the work done than any other. In a rectangular cast-iron box of any size (depending on the make of gas) is a series of rectangular tubes of wrought-iron, to which wrought-iron per- forated plates are fastened, turned down at the sides till they dip into the liquor. The perforations are ^V of an inch diameter, and ^ of an inch apart. The gas passes down between the tubes and through the side perforations into spaces filled with liquor, and, bubbling upwards, is again broken up by finding its way through the horizontal per- forations into the open space above, and so along to the outlet of the apparatus. Means are provided for securing an active circula- tion of the liquor, which is constantly flowing through it from the adjacent scrubber, and away by an overflow to the well. Walker's washer is somewhat similar to the foregoing, with the exception of one or two details. It is constructed of cast-iron TOWER SCRUBBERS 133 plates and is rectangular in form. The gas enters at the bottom into a central chamber, from which it passes into a number of longitudinal inverted troughs, open at the bottom and closed at the end. The lower ends of the troughs are slotted and sealed in liquor. The gas in passing into the top portion of the troughs displaces the liquor seal and bubbles through the slots to the surface, and on to the outlet. Other makes of washers are those of Cockey & Sons, Kirkham, Hulett, & Chandler, and R. & J. Dempster. THE TOWER SCRUBBER. The tower scrubber (Fig. 74) is a cast-iron vessel, either rect- angular or cylindrical (the latter shape being preferred), erected on end, through which the gas is made to pass in an upward direc- tion after issuing from the washer. Its primary use is to purify the gas from ammonia by the aid of water, advantage being taken of the well-known great affinity of ammonia for that liquid. Water, at mean tempera- ture and pressure (60 Fahr., baro- meter 30"), dissolves 783 times its volume of ammoniacal gas that is, undiluted ammoniacal gas. When the latter is mixed with other gases, as in the case of coal gas, the power of water to arrest it is not nearly so great. It also arrests a considerable proportion of the sulphuretted hydrogen and carbon dioxide. This is accomplished by filling the vessel wholly or in part with either coke, boulder-stones, brickbats, roof or draining tiles, furze, or layers of thin boards set on edge, about 5 to 7 hi. in width, | of an inch thick, and from to f of an inch apart ; the material FIG. 74. 134 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS being kept constantly moistened by a stream of water trickling from a suitable distributing apparatus fixed in the crown.- When the coke or other material is placed in layers, it is sup- ported on grids fixed at convenient distances apart ; and opposite each space a manhole, secured by a movable lid or cover, is pro- vided, so as to afford access to the interior, either for examination or renewal of the contained material. The Livesey scrubber is fitted with boards J of an inch thick, ii in. wide, placed on edge, and kept apart by strips or blocks of wood f of an inch square ; thus making one board to i in. The tiers are separated by 2-in. square cross sleepers. The first cost of filling with boards is greater than when coke or other material is employed ; but it possesses the marked advantage of not fouling up, and will rarely or never need re- . newing. The gas FIG. 75. cannot form narrow channels in its passage through the vessel, but is constantly being broken up and brought in contact with the water that drips from all sides. Green's filling medium con- sists of canvas screens depending from transverse rods. Open scrubbers are also used without any of the materials above men- tioned. In such cases the column of gas in its upward progress is met by a descending shower of spray from a Gurney jet (Fig. 75). The most efficient tower scrubber is the cylindrical, standing in height about five to seven times its diameter. Owing to the difficulty of securing an equal distribution of water or liquor, TOWER SCRUBBERS 135 the diameter should not exceed 10 ft. in the largest works. As a general rule, 8 ft. diameter is preferable ; for, to obtain the full benefit to be derived from this apparatus, there should be imme- diate contact of the gas with the water or liquor in a state of minute subdivision. Height is an important factor in a tower scrubber. Experience has proved that the best filling is thin, rough-sawn boards, placed in alternate layers on edge one over the other, or canvas screens, as before described. When coke is used as the scrubbing material, it may be placed in six or eight layers, with a space of about 6 in. between each. Whatever material is used in filling the scrubber, it is important that all parts of its surface should be wetted as equally as possible. The proper action of the scrubber depends on this. The necessity of a good water distributing apparatus is there- fore obvious. Not only should this be of good construction in the first instance, but it should always be maintained in efficient working order. The gas enters at the bottom of the vessel, and the water or liquor at the top. The gas in travelling upwards is completely broken up, fresh surfaces being constantly presented to the descending drip, and to the wetted sides of the filling material, against which it is rubbed or scrubbed all the way up until it emerges by the outlet at the top. A trapped overflow at the bottom conveys the liquor to either the washer or the tar well. The gas, before entering the scrubbers, should have the whole of the tar eliminated from it ; and to ensure this, a washer or tar extractor may be employed, either as a separate apparatus, or placed in the bottom of the tower. The weak ammoniacal liquor from the hydraulic main and con- denser may be employed for distribution through the tower. The object of using this is to arrest a proportion of the carbon dioxide and sulphuretted hydrogen, as well as the other sulphur com- pounds, for which ammonia has a strong affinity, thus relieving the lime and oxide purifiers, and saving labour and purifying materials. The weak liquor is also by this means brought up to the requisite commercial strength. One method frequently adopted of applying the water or liquor is by a pipe passing through the crown or side of the vessel, from which pipe smaller tubes, pierced with holes, radiate towards the circumference. This may be made either fixed or revolving, the latter being the most efficient. In the Mann scrubber, the I 3 6 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS uppermost part of the tower containing the distributor is made about 2 or 3 in. wider than the rest, in order that the sides of the vessel may be wetted as well as the contained material. In this wider portion, and underneath the dis- tributing tubes, there is a revolving layer of birchwood twigs, lessening in depth to- wards the circumference, and the water falling upon this is equally distributed throughout. This arrangement requires the use of a small engine and gearing to produce the slow rotary motion. To obviate the necessity for an engine, a Barker's mill or other similar appliance is sometimes used for producing the re- quired motion. The mill is usually fed in- termittently from a tilting box, or a vessel holding several gallons of water, and fitted with a valve and float. For small scrubbers, the water or liquor feeding arrangements may be as shown in Fig. 76, where a balanced tumbler is constructed to hold a quantity of water or liquor, and takes its supply from an over- head tank. The construction of the tumbler is such that, when filled with water or liquor, it overturns and empties its contents through a sealed pipe, when it returns to its original position. Where the quantity of liquor supplied is large a small turbine may be adopted for turning the distributor. With the introduction and perfecting of the rotary washer- scrubber has come a gradual modification of the views formerly held in regard to the superiority of the tower form. It is now admitted that the rotary apparatus is of much excellence, being more under control and more certain in its action than the other. It by no means follows, however, that the tower scrubber should be discarded. The best provision to make for scrubbing purposes is to apply one tower and one rotary apparatus for each stream of gas. That is to say : Assuming a works where the gas is sent in one continuous stream through the different appliances of purifica- tion, then one tower and one rotary scrubber will suffice. Thus : FIG. 76. FIG. 77. TOWER SCRUBBERS 137 When the make is sent through the apparatus in several streams as should be the case in large works the like provision is made for each stream. Thus : FIG. 78. The question as to the capacity of the washer-scrubbers will be decided by the quantity of gas they are intended to pass ; whether half, one, or two million cubic feet, and so on, per day of twenty-four hours. Adopting this arrangement, the tower scrubber would be supplied exclusively with weak ammoniacal liquor, and the washer-scrubber with clean water ; the supply of liquor, which should be plentiful, being moderated or increased according to the season of the year and the quantity of gas being passed. In works where there are no washer-scrubbers, but towers only, the latter are most economical and effective when they are used in pairs (Fig. 74), the gas being passed through first one and then the other. In such case, weak ammoniacal liquor should be pumped liberally through the first, and fresh water, hi the proportion of 2 to 3 gallons per 1000 cub. ft. of gas passing, through the second scrubber. When more than one pair of tower scrubbers are employed, the gas should be distributed in equal proportion through the several pairs simultaneously not through each in succession. Tower scrubbers, when used alone, and not in conjunction with the washer-scrubber, should have an aggregate cubical volume of at least 9 ft. for each 1000 cub. ft. of gas made per day of twenty- four hours, taking the maximum production as the basis of the calculation. For example, take a works producing in the depth of winter 600,000 cub. ft. of gas per day of twenty-four hours Then, 600 x 9 = 5400 ft., cubical volume required. 138 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS This would be supplied by Two scrubbers, each 8 ft. diameter and 56 ft. high. Or again, take a works producing 1,000,000 cub. ft. per day Then, 1000 X 9 = 9000 ft., cubical volume required. This would be supplied by Two scrubbers, each 10 ft. diameter and 58 ft. high. Where the washer-scrubber is also employed, one tower in each of the above instances is sufficient. THE WASHER-SCRUBBER. The washer-scrubber has come largely into use and deservedly so, as it is capable of removing the last vestige of free ammonia from the gas, with also a proportion of the other impurities. The predominant feature of the several forms of washer-scrubbers is a cast-iron tank or vessel, either cylindrical or rectangular, with semicircular top. The vessel is divided laterally into a number of compartments, the lower portions of which are kept supplied with liquor or water, and through these, chambers containing wood balls or bundles, or other filling medium, exposing a large surface, are made to revolve on a central shaft, at a slow speed. This apparatus, as has already been said, has largely supplanted the tower scrubber, by reason of its being more manageable, as well as more certain in its action as an ammonia extractor. Amongst the modern designs of washer-scrubbers in the market, the " Standard " of Kirkham, Hulett, & Chandler, the " Eclipse " of Clapham Brothers, the " Brush " of W. C. Holmes & Co., and the " Whessoe," rank as foremost. The " Standard " washer-scrubber (Fig. 79) is in the form of a cylinder with a central revolving shaft, and to this are keyed strong cast-iron collars, each collar bearing an iron frame, to which boards J in. thick are attached, kept T a 6 - in. apart by means of wood deflectors. These latter, being notched at one end, pick up the liquor at each revolution of the shaft, and distribute the same over the boards, which also pass through the liquor. The division plates in the " Standard " washer fill the whole diameter of the vessel, with a circular opening made at the centre for the passage of the gas. WASHER-SCRUBBERS 139 i 4 o NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS The " Eclipse Ball " washer-scrubber (Fig. 80) consists of a rect- angular vessel with semicircular top. The lower portion of the vessel is divided laterally by cast-iron plates into a series of chambers, these chambers being kept full of liquor or clean water, as the case may be, depending upon the position of the chamber with regard to the fresh water inlet. Keyed to the central revolving shaft are a number of cylinders, one to each chamber, FIG. 80. Laycock & Clapham's "Eclipse Ball" Washer-Scrubber. faced as to their outer edges, so as to work gas-tight against the outer case, thereby preventing " short-circuiting " of the gas from one compartment to another. The cylinders are divided into a number of divisions by perforated steel plates, and each division is filled with wooden balls ij in. diameter, having a hole J in. diameter through the centre. The balls are kept thoroughly wet by means of perforated buckets attached to the cylinders which dip into the liquor at each revolution of the main shaft. The " Brush " washer-scrubber (Fig. 81) is cylindrical in form, and is divided internally into a number of compartments by means of wrought-iron plates bolted between the flanges of the outer shell. Other circular iron plates, one to each compartment, are keyed to the central revolving shaft, and to these plates are secured circular brushes, which press close to the fixed sides of the compartments, the gas reaching each compartment only by passing through the wet brushes. The " Whessoe " washer-scrubber (Fig. 82) consists of a cylindrical outer vessel divided into separate chambers similar to the other rotary types. The washing devices consist of segmental WASHER-SCRUBBERS 141 clusters of sheet steel, or thin boards, spaced with wooden distance pieces, and keyed to the central shaft. FIG. 81. Holmes & Co.'s "Brush" Washer-Scrubber. In this washer the end plates are made Q -shaped, the object being to prevent oscillation and also to dispense with the use of cradles. FIG. 82. "Whessoe" Washer-Scrubber. Anderson's combined washer and scrubber consists of a rectangular cast-iron vessel, standing on end, and in height about five times its width. The vessel is divided into compart- ments, each containing a drum caused to revolve by suitable gearing. The circumference of each drum is fitted with a brush of whalebone or other fibre. These fit exactly into the 142 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS space allotted for them, and, in revolving, dip into the liquid which partially fills the several divisions. The scrubber stands on an Anderson washer (see p. 132). A small stream of pure water at the rate of 10 to 12 gallons per ton of coal carbonized, is kept flowing into the top compart- ment through a funnel and sealing tube, and gradu- ally descends by way of the gas- pipes connecting the chambers till it enters the washer, from which there is an overflow pipe to the well. The gas enters the washer at the bottom, and is first relieved of the tar remaining after condensation ; thence it passes through the re- volving brushes, meeting different strengths of liquor in each division, till it reaches the upper one contain- ing pure water, and away by the outlet. By this means the whole of the ammonia and a large proportion of the other impurities are removed. In addition to the apparatus described above, the " purifying machine " made by C. & W, Walker, is a powerful washer and scrubber combined. The machine (Fig. 83) consists of a retangular cast-iron vessel containing in the lower part a Walkers' washer. FIG. 83. Walkers' " Purifying Machine." CENTRIFUGAL WASHERS 143 The gas, after leaving the washer, ascends through rectangular openings, over which are fixed devices containing wetted boards, into the next chamber above, and then from chamber to chamber, having to pass between the wetted boards in each tier, until it arrives at the top of the machine freed from all traces of the impurities. In each of the superposed chambers over the inlets are placed device boxes containing thin boards f in. apart, and through these spaces the gas travels on its way to the outlet. The frames containing the devices and boards are attached on each tier to the vertical shafts, which are themselves actuated by dipping beams on the top of the machine, and by this means are frequently immersed in the gas liquor or clean water contained in each tier of the machine. Clean water is admitted into the top of the machine through a self-acting seal box, at the rate of 10 gallons per ton of coal carbonized. Centrifugal Washers of the vertical type are now being manufactured. The feature of this type is that the gas has to pass through a number of finely divided sprays of water or liquor. The washers of Dr. Feld, Kirkham, Hulett, & Chandler, W. C. Holmes & Co., and R. Dempster & Sons are of this description. Feld's centrifugal washer the invention of Dr. Feld, a German chemist consists of a number of cast-iron chambers, cylindrical in form, and placed one above the other, with a central shaft to which are attached sets of cones, each set consisting of four plates placed one inside the other. The lower ends of the cones dip into a dish-shaped casting containing water or other liquid. The central shaft with the cones attached revolves at the rate of about 120 revolutions per minute and causes the liquor contained in the castings to be drawn up on the inside of the cones and then thrown off at a tangent, at the upper edges, with great velocity against the walls of the chambers. The gas travels in an upward direction from chamber to chamber through openings arranged in the castings, and in so doing passes through the spray of liquor in each chamber. Kirkham's " Standard " centrifugal washer (Fig. 84) consists of a vertical cylindrical cast-iron vessel divided into a number of chambers and traversed by a shaft to which are attached spraying devices for lifting and spraying the washing liquid, thus bringing it into intimate contact with the gas. I 4 4 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS The gas is admitted into the lowest washing chamber, and passes through the spray to the central opening in the bottom of the second washing chamber, through the spray ; then into the third chamber, and so on throughout the vessel. FIG. 84. Kirkham, Hulett, & Chandler's Centrifugal Scrubber. The washing liquid is admitted at the top of the apparatus, and flows through the centre openings from chamber to chamber, and is finally run off. The machine is driven by pulleys and belt, by bevel gearing and belt, or by bevel gearing direct from an engine crankshaft. Dr. Frankland gives the following useful table, showing the BY-PASS MAINS AND VALVES 145 number of volumes of various gases which 100 volumes of water at 60 Fahr. and 30 in. barometric pressure can absorb : Ammonia .' . . 78,000 volumes. Sulphurous acid . . 3,300 Sulphuretted hydrogen . 253 Carbon dioxide . . 100 defiant gas . . 12*5 C Not determined, but probably more Illummatrng hydrocarbons soluMe than Oxygen . . . 37 volumes. Carbon monoxide . . 1-56 Nitrogen . . 1-56 Hydrogen . . 1-56 Light carburetted hydrogen i'6o When water has been saturated with one gas, and is exposed to the influence of a second, it usually allows a portion of the first to escape, whilst it absorbs an equivalent quantity of the second. In this way a small portion of a not easily soluble gas can expel a large volume of an easily soluble one. BY-PASS MAINS AND VALVES. In connection with the foregoing apparatus viz., the con- denser, exhauster, washer, tower scrubber, washer-scrubber and centrifugal washer by-pass mams closed with valves or water-traps should be provided, hi order to allow of any of them being put out of action for cleaning or repairs. The exhauster by-pass is closed with a flap valve, so that, in case of sudden stoppage of the machinery, the valve opens by the pressure of the gas being thrown against it, and allows the gas to flow unchecked. TAR AND LIQUOR WELLS AND TANKS. The tar and ammoniacal liquor underground wells may be built either of bricks laid in cement and carefully puddled at the bottom and sides, or of cement concrete rendered over the whole inside surface, or formed of cast or wrought-iron or steel plates, bolted together, and having either planed or caulked or riveted joints. The iron vessel is preferable when the construction of a good foundation is likely to be a matter of great expense. The well or wells should be of capacity sufficient to contain L 146 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS six weeks' make of material, reckoning from the maximum daily production. Less than six weeks' storage space will serve when the liquor is manufactured into sulphate of ammonia on the premises. Another well of smaller dimensions, the size depending on the magnitude of the works, ought to be provided, to serve as a lute or seal, into which the drip-pipes from the different apparatus should dip. From this, at a depth of about 15 or 18 in. below the surface of the ground, an overflow-pipe or channel conveys the condensed products into the larger reservoir. In some works the tar-pipe is taken direct from the hydraulic main into the large well, and there sealed by being made to dip into a vertical pipe secured to the bottom of the tank. This is objectionable, as, in case of stoppage, it is difficult of access. Again, there is always the liability of an escape of gas from that portion of the pipe within the well. Further, where flushing of the hydraulic main is practised, the rushing liquor carries with it a quantity of gas which is liberated within the well. It ^s also important that the tar should be cooled somewhat before entering the larger receptacle. In each of these cases the gas or vapour, mixing with the contained air within the well, would explode with disastrous consequences on contact with a light. Accidents which have occurred have been due to one or other of these causes. In all cases the wells should be covered over to exclude sur- face and rain water, and prevent the possible loss of ammonia by evaporation. In addition to the underground well, an elevated cast-iron LIQUOR tc AND 2 LIQUOR =0* FIG, 85. Vertical Section. FIG. 86. Plan. cistern or tank is indispensable in a well-appointed gas-works. Into this the tar and liquor are pumped from the underground well, and suitable draw-off pipes, furnished with stopcocks or valves, serve TAR AND LIQUOR WELLS AND TANKS to discharge the material into the barrels, trucks, or barges of the purchasing contractor. The cistern may be divided in two by means of a partition plate reaching to within about 6 in. of the top, over which the ammoniacal liquor will flow, separating itself from the tar by reason of its lower specific gravity. A tar and liquor separator, for placing in the ground in any convenient position near to the underground well, is shown in sectional elevation and plan in Figs. 85 and 86. It consists of a cast-iron vessel, about 4 ft. square and 4! ft. deep, for a con- siderable sized gas-works. The division plate extends from the top of the vessel to within 4 in. of the bottom ; the diaphragm, over which the tar escapes into its separate well, being placed i J in. lower than the other diaphragm for the ammoniacal liquor. TABLE. Contents of Circular Tanks or Wells in Gallons for each Foot in Depth. Diameter Canons * or each Diameter. Gallons for each j . Foot in Depth. Diameter. Gallons for each Foot in Depth. Ft. In. Ft. In. Ft. In. 9 o 397-6 16 6 1336*4 24 o 2827-4 9 3 42O"0 16 9 1377-2 24 3 2886-7 9 6 443-0 17 o 1418-6 24 6 2946*5 9 9 466-6 17 3 1460-7 24 9 3006-9 10 490-9 17 6 1503*3 25 o 3068*0 10 3 5157 17 9 1546*6 25 3 3129-6 10 6 18 o 1590*4 25 6 3191*9 10 9 567-3 18 3 1634*9 25 9 3254*8 II 594-0 18 6 1680*0 26 o 3318-3 ii 3 621*3 18 9 1725-7 . 26 3 3382-4 II 6 649-2 19 o 1772-1 26 6 3447'2 ii 9 677-7 19 3 1819*0 26 9 35I2-5 12 706-9 19 6 1866-6 27 o 3578'5 12 3 736-6 19 9 19147 27 3 3645;i 12 6 767-0 20 o 1963*5 27 12 9 798-0 ; 20 3 2012*9 27 9 3780*0 13 o 829-6 20 6 2O62"9 : 28 o 3848-5 13 3 861-8 20 9 2113*5 , 28 3 i 3917-5 13 6 894-6 21 2164*8 ! 28 6 3987-1 13 9 928-1 21 3 2216*6 28 9 4057*4 14 o 962"! 21 6 2269-1 j 29 o 4128-3 14 3 996-8 i 21 9 2322*1 29 3 4199*7 14 6 1032-1 22 2375-8 29 6 4271*8 14 9 io68'o 22 3 2430*1 29 9 4344-6 15 1104-5 22 6 2485-0 30 4417*9 15 3 1141-6 22 9 2540*6 30 3 4491-8 15 6 U79-3 23 o 2596-7 30 6 4566*4 15 9 1217*7 , 23 3 2653-5 ! 3 9 4641*5 16 o 1256*6 23 6 2710-8 4717*3 16 3 1296-2 23 9 2768-8 31 3 47937 L 2 148 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS PURIFICATION. Impurities in Crude Coal Gas. Though the removal of any- thing which otherwise would leave the gas impure is, strictly speaking, an act of purification, and purification therefore com- mences in the hydraulic main and is carried on from this point through all the apparatus preceding the purifiers, the word puri- fication is generally used as meaning the process in the " purifiers " proper whereby the carbon dioxide and compounds containing sulphur are eliminated from the gas. The chief impurities that are removed from the crude gas before it reaches the purifiers are : aqueous vapour, tar, and ammonia. The aqueous vapour and tar begin to condense and are par- tially removed in the hydraulic main and pipes leading to the condensing apparatus, where, if this is of sufficient capacity, and otherwise adapted to the performance of the work required of it, the tar should be nearly all removed. Owing to the strong affinity of ammonia for carbon dioxide and for sulphuretted hydrogen, and to the partial solubility of these acid radicals in water, the hydraulic and foul mains, condensers, washers, and scrubbers are also efficacious in removing a portion of these impurities from the gas. The gas as it leaves the scrubbers usually contains from ij to 2| per cent, by volume of carbon dioxide, and though the removal of this impurity is not compulsory by statute, its elimination is a necessity where the sulphur compounds are to be dealt with. Further, the presence of I per cent, of carbon dioxide will reduce the illuminating value of gas of 17-candle power by at least half a candle. The impurities containing sulphur are of two kinds : (i) Sul- phuretted hydrogen and substances such as carbon bisulphide, which yield sulphuretted hydrogen on being passed over heated platinum ; (2) substances which do not yield sulphuretted hydrogen under the above condition, but which are burnt to sulphuric acid. The sulphur impurities other than sulphuretted hydrogen are classed as sulphur compounds. Without at present entering into a description of the continuous processes that have been brought forward for the removal of the impurities by liquid reagents in closed vessels, there may be said to be two systems whereby the carbon dioxide and the impurities PURIFICATION 149 containing sulphur are removed viz., purification by lime and purification by oxide of iron. Purification by Lime. Lime quick or caustic lime is calcium oxide, and is generally obtained by subjecting limestone, which is almost pure calcium carbonate, to a red heat, whereupon the calcium carbonate is decomposed, carbon dioxide gas being expelled and calcium oxide left as a residue. It has been proved that dry calcium oxide will not combine to any appreciable extent with either carbon dioxide or sulphuretted hydrogen, at ordinary temperatures ; but if the quicklime is slaked, with a slight excess of water, the calcium hydrate will rapidly absorb carbon dioxide, with the formation of calcium carbonate according to the equation Ca(OH) 2 + C0 2 = CaCO 3 + H 2 O Calcium hydrate also absorbs sulphuretted hydrogen, with the formation of calcium sulphide in accordance with the equation Ca(OH) 2 + H 2 S = CaS + 2H 2 O but the reaction is rather sluggish, owing to the sulphide caking and enclosing particles of unaltered hydrate. With an excess of water in the calcium hydrate, calcium hydro- sulphide is formed, but this is rapidly decomposed into calcium hydroxy-hydrosulphide, a change which is accompanied by the evolution of heat. Ca(OH)o*Aq. + 2HS = Ca(SH) 2 + #Aq. +2HoO Ca(SH)o + H 2 O = CaSH-OH + H 2 S Carbon bisulphide is not absorbed by either calcium oxide or calcium hydrate, and neither are the sulphide or hydrosulphide active materials in its elimination. The active material for the absorption of carbon bisulphide is the hydroxy-hydrosulphide of calcium, which combines with the carbon bisulphide to form calcium thiocarbonate. This action is accompanied by the evolution of sulphuretted hydrogen according to the equation 2CaSH-OH + CS 2 = Ca(OH) 2 CaCS 3 + HoS 3CaSH-OH + CS 2 + H 2 O = 2Ca(OH) 3 CaCS 8 + 2~H 2 S The reason of the occasional inactivity of the purifiers set aside for the elimination of carbon bisulphide, is that too much sulphu- retted hydrogen has been passed into the lime, and that instead of 150 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS the active hydroxy-hydrosulphide, the inactive hydrosulphide has been formed. The excess of sulphuretted hydrogen can be removed by breaking up the lime and exposing it to the air, or by allowing air to pass through the purifier. It is well known that in lime purification carbon dioxide drives the sulphuretted hydrogen and sulphur compounds before it, decomposing both the calcium sulphides and the thiosulphates with the elimination of sulphuretted hydrogen and carbon bi- sulphide respectively, and the formation of calcium carbonate. When the foul gas enters a clean purifier the combination of the lime with the carbon dioxide and sulphuretted hydrogen proceeds side by side, only the carbon bisulphide being driven forward, and this double action continues as long as there is left in the purifiers any uncombined lime. But when the box has become fouled, then the carbon dioxide decomposes the calcium sulphide, driving forward the sulphu- retted hydrogen as previously explained. Cream or milk of lime was used in purifying in the early days of gas manufacture, and though this was thoroughly efficient, and is probably the most economical method of employing the lime, it has been generally discarded on account of the obnoxious character of the refuse material, " blue billy," as it was called, and the difficulty of getting rid of it. The lime should be prepared by being slaked with clean water a day or two before it is required for use. "If placed in the purifiers before this necessary interval has elapsed, it is liable to cake or become more compact than it otherwise would.- On the other hand, hydrate of lime absorbs carbon dioxide from the atmosphere, and its purifying power is nullified in proportion to the extent of such absorption. It should not, therefore, be prepared for any great length of time before it is needed. It is a mistake to place the prepared lime in the purifiers in a comparatively dry and almost powdery state. Lime used in this condition is less effective than when thoroughly moistened. It is also a wasteful method of using the lime, as a large proportion of the material will be found unspent and almost untouched by the impurities when the vessel requires to be changed. The finely divided lime is also more liable to cake than the other, and thus to increase the back pressure. When the production of gas PURIFICATION BY OXIDE OF IRON 151 is great, as in the depth of winter, these disadvantages are strongly felt. The lime should be well watered. A hose pipe or india-rubber tube, terminating in a copper spreader or rose, is useful for this purpose. It should then be passed through, by being thrown against, a screen made either of parallel steel rods f in. thick and i in. apart, or of strong wire having I in. square meshes. This not only removes the stones or flints which are less or more present, but it gives a granular character to the prepared material, in which condition it best performs its work in the purifiers. Mr. Hislop has a process of calcination in suitable kilns, by which the spent lime is converted into quicklime to an almost unlimited extent, and at considerably less cost than new lime. A nuisance is thus got rid of, and further economy in purification effected. Purification by Oxide of Iron. Oxide of iron possesses the property of combining with sulphuretted hydrogen, but it has no affinity for carbon dioxide and carbon bisulphide ; hence when this oxide is used exclusively, the two latter-named impurities are still present in the gas as supplied from the holders. The action of the sulphuretted hydrogen on the hydrated oxide of iron forms ferric sulphide, ferrous sulphide and water, according to the equations, thus (1) FeoOg-HoO + 3H,S =FeaSs + 4HoO (2) Feo0 3 -H 2 + 3H 2 S = 2FeS +S + 4H 2 O Although oxide of iron, pure and simple, has no affinity for carbon bisulphide and other sulpho-carbon compounds, from the ob- servations made at the several Metropolitan gas-works by Mr. R. H. Patterson was deduced the interesting fact that the sulphur which is present in a state of minute division in the oxide of iron, after the latter has been in use for some time and frequently revivified, possesses the power of arresting apportion of the carbon bisulphide. The hydrated peroxide of iron may be either the natural oxide, bog-iron ore as it is called, found largely deposited in some of the bogs in Ireland and elsewhere, or the artificial oxide obtained as a waste product from various processes of the manufacturing chemist. Oxide of iron possesses this advantage over lime : After it has been in the purifier, and has taken up its quantum of sulphuretted hydrogen, it can be revivified either in situ or by exposure to the air. 152 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Accordingly, when this material is revivified by exposure, a floor is provided on which it can be spread out and turned over for revivification. At the Manchester Gas-Works, a horse and plough are employed for turning over the foul oxide. When taken out of the purifier it is sulphide of iron, of a dense black ; and after exposure it changes to its original reddish brown colour, oxygen having been taken up and sulphur deposited in the free state in the mass according to the equations (1) 2Fe 2 S 3 + 3O 2 = 2Fe 2 O 3 + 6S (2) 4 FeS + 3 2 = 2Fe 2 3 + 4$ Occasionally, oxide of iron becomes sluggish in its action. This may be due to several causes, namely (i) the oxide may be too dry ; (2) it may have an acid reaction ; or (3) it may be due to caking. Temperature, also, affects the oxide. In order to overcome dryness, the gas may be allowed to enter at the top of the purifier and out at the bottom the reverse of the usual procedure : the object being to allow the moisture to deposit on the top layer of oxide and on the underside of the cover, when the condensed products will soak through the mass to the bottom of the purifier, thus keeping the oxide in a moist state. It is generally agreed that oxide of iron should be slightly alkaline, if its activity is to be retained unimpaired. No special provision, however, is necessary ; the small percentage of ammonia in the gas that escapes removal in the washing plant is usually sufficient for this purpose. The caking of oxide arises only with horizontal grids. The difficulty may be overcome by adopting the hurdle or other allied forms of grid. When the sulphur is found in it to the extent of about 50 to 60 per cent, by weight (the proportion depending on the quality of the oxide), the material is sold to the manufacturing chemist, and replaced by fresh oxide. In using fresh oxide of iron, it is necessary to exercise certain precautions. The foul material, on its exposure to the air for the first two or three times, absorbs oxygen so rapidly as often to generate very intense heat, the whole mass frequently becoming red hot. Should this occur in the purifiers, the danger is consider- able, and the wood grids may be completely destroyed. When- ever, therefore, a purifier containing such new oxide has been DIFFERENT SYSTEMS OF PURIFICATION 153 put out of action, it should be emptied without delay. The danger of ignition may be overcome by mixing the new oxide with a proportion of the spent. Foul oxide should not be spread out immediately on being removed from the purifiers. If it is allowed to remain in the heap for a space of twelve to twenty-four hours, and then distributed over the floor, the revivification is more complete, whilst the liability to ignition is reduced. Average Composition of the Richer Descriptions of Native Bog Ore for Purifying Purposes, dried at 212 Fahr. (King's Treatise.) Ferric oxide . . . ; . 60 to 70 per cent. Organic matter . * , . 15 to 25 Silica . . . . . . 4 to 6 Alumina . . . ... . I As generally used, the material contains 30 to 40 per cent, of water. Wei don Mud. As a substitute for oxide of iron for the removal of sulphuretted hydrogen, the bye-product from the manufacture of bleaching powder, commonly called Weldon mud, may be used. The Weldon mud as taken from the bleach-works is unsuitable for use in a purifier owing to the .superabundant amount of water contained in it, and also the presence of a large percentage of calcium chloride, which attracts more water owing to its deli- quescent nature, and so forms a sloppy mixture in the purifiers. To overcome this, the Weldon mud is washed until only a small percentage of calcium chloride is left, and then partially dried. The mud as then prepared for the purifiers contains about 50 per cent, of water, 30 per cent, of manganese dioxide, and 20 per cent, of a mixture chiefly composed of manganese monoxide, lime, calcium chloride, and silica. The chief advantage claimed for Weldon mud over oxide of iron is its superior absorbent power. Like oxide of iron, it can be easily revivified either in situ or in the ordinary manner. Systems of Purification. Lime alone, or lime and oxide of iron, when properly applied, are capable of freeing the gas entirely of the whole three impurities, carbon dioxide, sulphuretted hydro- gen, and carbon bisulphide. This brings us to a consideration of the different systems whereby the purifying material is applied. 154 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS In works where there are no statutory restrictions as to the amount of sulphur impurities other than sulphuretted hydrogen in the purified gas, it is rarely that any special precautions are taken for the removal of these impurities. There are other works, again, where the carbon dioxide is not removed from the gas, though, as has been previously stated, to the detriment of the illuminating power. Beginning with the lowest degree of purification viz., the removal of sulphuretted hydrogen alone, the method usually adopted is that of four vessels filled with oxide of iron, and worked on the rotation system, three vessels always " on," and one " off " for renewal. For the removal of carbon dioxide and sulphuretted hydrogen there are two systems in vogue. First, by the use of lime alone in four vessels worked on the rotation system ; or, second, by the use of four vessels charged with oxide of iron for the removal of the sulphuretted hydrogen, followed by two vessels charged with lime for the removal of carbon dioxide. Where it is necessary that the sulphur impurities should be removed as well as the carbon dioxide and sulphuretted hydrogen, the method of purifying expounded by the Referees in their report to the Board of Trade on sulphur purification at the Beckton Gas- Works, January 31, 1872, and also by Dr. Odling, somewhat more in detail, in his lecture on Sulphide of Carbon, delivered at the annual meeting of the British Association of Gas Managers, held in London in June, 1872, may be adopted. To accomplish this perfect purification in accordance with the suggestions made by Dr. Odling, three sets of purifiers are required ; the gas passing through the first set into the second, and on to the third, from which it makes its exit through the station-meter into the holders. The modus operandi is as follows : * Let it be assumed that three sets of purifiers, consisting of four vessels each, are employed. Nine of these are constantly in action, three being at rest (one from each set), for the purpose of changing or revivifying the purifying material. The first and second sets are charged with lime, the third set with oxide of iron. Say the whole nine are newly charged. On the gas from the DIFFERENT SYSTEMS OF PURIFICATION 155 scrubbers entering the first set, the lime is acted on by the carbon dioxide and sulphuretted hydrogen simultaneously, leaving the carbon bisulpliide at the beginning of the process to pass unabsorbed. After they have worked for some time the sul- phuretted hydrogen in the first set is gradually expelled by the incoming carbon dioxide, for which the lime has a stronger affinity. The second set is now being fouled with sulphuretted hydrogen, the lime being wholly or in part changed in character, having become calcium sulphide, in which state it has an affinity for, and consequently arrests, the carbon bisulphide ; whilst the un- absorbed sulphuretted hydrogen passes on to be taken up by the oxide of iron with which the final set of purifiers is charged. By the application of the proper tests at the several sets of jmrifiers, the time for changing the material is ascertained. The system adopted at the London Works, and known as the Beckton System, is probably the most perfect for the removal of all the impurities. It consists of four sets of vessels, each set being worked on the rotation system. The first set is filled with time for the removal of carbon dioxide, the second set with oxide of iron for the removal of sulphuretted hydrogen, the third set with lime for the removal of carbon bisulphide, and the fourth set with lime for the final elimination of any sulphuretted hydrogen from the sulphide of lime boxes. The foul gas, after it has passed through the first boxes, and whilst charged with sulphuretted hydrogen, is allowed to enter the third set of purifiers until the lime in these has become sufficiently sulphided for the removal of the carbon bisulphide, when it is made to enter the second set for the removal of the sulphuretted hydrogen, and theft on to the third set for the removal of the carbon bisulphide. As has been previously explained, the formation of calcium thiocarbonate in the sulphide boxes is always accompanied by an evolution of sulphuretted hydrogen, which, in this case, passes on with the gas into the last set of boxes. These are never allowed to become more than slightly fouled before they are renewed the half fouled material being transferred to either the first or third set for further use. 3' The question of supplying gas entirely free from sulphur in any form is a formidable one for gas authorities ; not so much because of the cost (though "that is considerable) of erecting the additional sets of purifiers, as from the difficulty of providing the 156 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS necessary ground space for their erection. In new works about to be constructed the thing is easily arranged ; but in the majority of works already established it would not be easy to carry the system into effect. As regards the question of cost, a careful estimate shows that to adopt the extended method of purifying as enunciated would entail an outlay of additional capital equivalent to close upon 2d. per 1000 cubic feet of gas sold. Coal Liming. Messrs R. 0. Paterson and Twycross have patented a process for the liming of coal with the object of reducing the amount of the sulphur compounds, and increasing the yield of ammonia, as well as aiding purification. The process consists in adding a regulated quantity of lime to, and distributed equally amongst, the coal. The lime, in the state of fine powder, is applied to the coal by means of a special apparatus, and both are then steamed so as to moisten the lime, thus encasing the surface of the coal in a fine layer of lime. The Use of Air In Purification. By forcing in a measured quantity of air at the inlet to the purifiers, revivification of the oxide of iron in situ can be effected by adopting the reverse action in the flow of the gas. The purifiers are thus made to continue in use for a greater length of time without changing, whilst it is remarkable that the oxide by this process can be charged with as much as 75 per cent, of free sulphur. Purifiers with a proportionately large area in comparison with the make of gas are required to obtain the full advantage of this process. In adopting the air process, two layers of oxide are preferable to one deep layer. Owing to the heat generated by chemical action, as well as to the deposition of the sulphur, a considerable increase or expansion in the bulk of the material takes place in the purifiers, and it is necessary, therefore, to allow ample room for the oxide to expand. A space of several inches should be allowed between the two layers, and the surface of the upper layer should be at least 3 in. below the top edge. Of course this applies only to horizontal grids, and not where " hurdle " or vertical grids are in use. Reverse Action. The essential feature of this system of purification in situ consists in admitting a measured quantity of air, DIFFERENT SYSTEMS OF PURIFICATION 157 generally 2j per cent, of the volume of gas, to the inlet of the purifiers, by means of a blower or steam injector, and a wet meter. The gas is admitted to a series of four purifiers, so arranged with centre or other valves to work them four on, that is to say, the gas passes through each of the purifiers in rotation, namely, one, two, three, four. When the gas in the second purifier shows a foul test, the valve is changed to work the last purifier in the series first in the order of four, one, two, three. The next change is to bring number three purifier first, the rotation being three, four, one, two. The last change is to bring number two purifier first, the order then being two, three, four, one. In the next change the gas is back at its original sequence of one, two, three, four ; thus 1st rotation 1234 2nd 4123 3rd 3412 4th 2341 Another system is that of changing the flow of gas to the purifiers periodically, say every 24 hours, instead of when the gas shows 'foul. The rotation in this system being : one, two, three, four ; two, three, four, one ; three, four, one, two ; four, one, two, three ; three, four, one, two ; two, three, four, one ; thus ist rotation 1234 2nd 2341 3rd 3412 4th 4123 5th ^ 3 4 i 2 6th 2341 The principle of both methods, however, is the same, namely, the abstraction of the bulk of the impurities in the first purifier, thus allowing the oxygen to fulfil its function of revivification in the succeeding purifiers. It is advisable to have catch boxes to the purifiers in the event of sudden fouling. The Use of Pure Oxygen in Purification. The chief objec- tion to the use of air for revivifying the oxide of iron in situ is the importation of a considerable volume of the inert gas nitrogen into the gas, reducing the luminiferous value of the latter. 158 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS It is obvious that if pure oxygen were employed instead of atmo- spheric air, the objection stated would be overcome. The cost of producing oxygen, however, renders its use prohibitory. Other Methods of Purification. Continuous purification is the ideal of both chemists and gas engineers. Various attempts have been made to accomplish it, but hitherto without success. The processes suggested and tried are full of interest, and it is worth while referring to them. The late R. H. Patterson patented a process of purifying by washing or scrubbing the gas in solutions of caustic soda and sodium sulphide, extracting the carbon dioxide and sulphur impurities, and so dispensing altogether with the ordinary lime and oxide of iron purifiers. The soda solutions, when saturated with the impurities, possess the important quality of being easily and perpetually revivified or restored to their original state on the gas-works, whilst the whole of the sulphur is secured for sale. The plan, however, has not been tried on an adequately large scale. Attempts have been made by Laming, Livesey, F. C. Hills, and others, to purify the gas in closed vessels by employing the ammonia found in the gas for arresting the other impurities. Unfortunately the loss of ammonia at each time of desulphurating the liquor, owing to its extreme volatility, prevented success in this direction under the conditions adopted. Claus's Process. This process of continuous purification in closed vessels, though not hitherto practically successful, is of such importance and promise as to merit a detailed description. The crude ammoniacal liquor, consisting of ammonium sulphide and ammonium carbonate, is passed through a series of towers, wherein it is exposed to the action of carbon dioxide (obtained as described below), whereby the ammonium sulphide is decomposed, sulphuretted hydrogen being liberated, and ammonium carbonate remaining alone. The sulphuretted hydrogen passes through and out of the towers in the opposite direction to that in which the crude liquor travels, and is disposed of in the manner described hereafter, whilst the ammonium carbonate solution passes forward into other towers in which it is heated to a temperature of 180 to 200 Fahr. At this temperature the ammonium carbonate, of a strength DIFFERENT SYSTEMS^OF PURIFICATION 159 equal to 10 or 15 oz. liquor, loses two-thirds or three-fourths of its carbon dioxide, and a corresponding quantity of caustic ammonia remains in the liquor passing from these towers. As only a portion of the carbon dioxide evolved in the heating vessel or towers is required for the above-mentioned decomposi- tion of ammonium sulphide, the surplus is allowed to escape in a regulated quantity, and may be used for other purposes forming part of the process. The sulphuretted hydrogen, after leaving the towers, is con- veyed to a closed furnace charged with oxide of iron, where a low incandescent heat is generated and maintained by the admission of a regulated supply of air. The oxide of iron, once heated, continues to absorb the sul- phuretted hydrogen, which, owing to the continued admission of air, is evolved in the lorm of sulphur, in finely divided particles, which is carried off and caught in chambers, so that the oxide does not require revivification, and the same quantity, kept hot by continual working, goes on indefinitely decomposing the sulphu- retted hydrogen sent through it. ' The purified ammoniacal liquor is then passed down distilling towers, into which steam is admitted, driving off the ammonia gas at the top, which is passed through cooling chambers where any ammonium carbonate carried with it deposits in crystals. Thence, as much of the ammonia gas as is required for the purposes of purification passes with the coal gas into a chamber, where they are allowed sufficient time to mix. The gas is then passed through scrubbing towers, where all the impurities are washed out in the liquor, which may be obtained of 40 to 50 oz. strength if required. Any surplus ammonia, being perfectly pure, can be used for making any of the salts of ammonia desired. The liquor flowing from the bottom of the distilling towers contains ammonium sulphocyanide, and may be used over and over again in the scrubbers instead of water, until the sulpho- cyanide accumulates to such a strength as to make it marketably valuable for chemical manufacture. A new process for the washing and purification of gas is that known as the " Burkheiser " system. The system is yet in its experimental stage, being tried in some places abroad. The object of the inventor is to substitute for the ordinary 160 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS scrubbers and washers, purifying plant, and sulphate of ammonia plant, the " Burkheiser " patent purifiers and " Burkheiser " gas and air scrubbers. The process embodies the following series of operations : (i) The absorption of sulphuretted hydrogen by means of artificial or natural ferric hydrate ; (2) The revivification of the fouled material, with the formation of sulphur dioxide. (3) The formation of ammonium bisulphite from the sulphur dioxide and a solution of ammonium sulphite ; (4) The formation of ammonium sulphite by the taking up of ammonia by the solution of ammonium bisulphite ; (5) The oxidation of ammonium sulphite to ammonium sulphate. The inventor also claims, by a combination of his process and the contact process for the manufacture of sulphuric acid, to convert ammonia direct into ammonium sulphate. Purifying House. The house to contain the purifiers should be lofty and well ventilated, not only for the comfort of the work- men employed therein, but to lessen or entirely remove the risk of explosion from any leakage of gas that might occur. Efficient ven- tilation of the purifying house is best attained by having one side of the house entirely open, the roof being carried on braced girders FIG. 87. supported at various points by cast-iron columns or steel stanchions. The house should also be arranged with a view to future extension : but this, indeed, applies to every structure within a gas-works with its constantly growing business. It is a convenient plan to build the house with a ground and upper floor, and to place the purifying vessels on the latter with the connections and centre or other valves underneath and fully exposed and accessible. The ground floor can thus be used for revivifying the oxide of iron, if that material is employed, or for other purposes (Figs. 87 to 92). The vessels are discharged through an opening in the bottom of each, closed by a gas-tight lid, and the fresh material is raised PURIFIERS 161 by means of an endless chain ladder, or other suitable elevating apparatus, to the floor above (Figs. 90 to 92). o 0\ FIG. 89. Purifiers. The purifying vessels are almost invariably made of cast-iron (though we have seen purifying vessels made of wrought-iron plates riveted together, and also of ferro-concrete) with sheet-iron or steel plate covers secured with suitable fastenings to prevent their being lifted by the inflowing gas pressing on their under surface. Malam's original arrangement of four in the set, with connections and a centre valve (Fig. 93), by which three of the vessels are kept in action and one out of use for renewal of the purifying material, is still generally adopted, and is the simplest and most convenient. In some works a second set of two purifiers is used in addition to the series of four, and these are connected together, and to the others, with single or four-way valves (Figs. 89 and 93). Under this arrangement the set of four is charged with oxide to arrest 162 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS the sulphuretted hydrogen, and the set of two with lime to take up the carbon dioxide, the gas passing through them in the order shown. In works where carbon dioxide is not removed from the gas there is less need for catch boxes. It is a good plan, however, where such boxes have been installed, to use them with oxide, as FIG. 90. it tends to economy in working by allowing the oxide in the preceding boxes to take up the maximum quantity of sulphur. In designing a set of purifiers, the engineer has to decide whether to have a ground- floor arrangement or to erect them on a super- structure of columns and girders (Figs. 91 and 92). In coming to a decision, all the circumstances financial and PURIFIERS 163 economical that are applicable to the particular works must be taken into account. FIG. 91. The first thing to consider is the available space. If the works is, congested, there is no alternative, unless additional land is acquired, to adopting the overhead system. At another works the site may be spacious enough to allow of the ground-floor arrangement with a revivifying shed. alongside. FIG. 92. With the overhead system, elevating and conveying plant have to be provided. The capital cost of the elevated as compared M 2 164 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS with the ground-floor position will range from 40 to 50 per cent, more. LJ 7^3 w u \ v o 1 \ f DISCHARGE o o PIPE I : o OFF FIG. 93. So far as labour saving is concerned, the overhead system has the advantage. The filling and emptying of the purifiers can be done in, roughly, one-third the time taken by the_ ground-floor PURIFIERS 165 system. Furthermore, there is no need for a separate revivifying shed, this being on the floor underneath the purifiers, or on a floor above. Until within recent years the water-lute purifier (Fig. 94) was the usual form, and in most works to-day this type of purifier is n use. g^ff^ff^^ FIG. 94. Luteless Purifiers. The introduction of luteless purifiers, however, by Henry Green, of Preston, and the subsequent improve- ments that have been made, has led to a general adoption of this system of construction (Fig. 95). The advantages which this system possesses over the water- lute type are many, not the least of which is the increase in the available purifying area. 166 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS The ordinary and best form is the square or oblong ; this shape is the cheapest, affords the largest area for the space occupied, and is also most convenient as regards the placing of the grids. The purifiers are arranged either separate as in the case of the FIG. 95. water-lute system, or continuous, with division plates. The latter arrangement is the more economical. There is practically no limit to the length and breadth of which this type of purifier may be constructed ; the depth is usually from 4 ft. 6 in, to 6 ft. PURIFIERS 167 The metal forming the plates should be } in. in thickness and the flanges 3j in. by J in., with bolt holes 6 in., apart and stiffening brackets midway between the bolt holes. The flanges of the top plates, in order to leave the top gangways clear of obstruction, should be internal, and the flanges to the side plates external, The position of the bottom plate flanges depends upon the situation of the purifiers, i.e. whether on a ground floor or superstructure. In the former case it is usual to have internal flanges and the bottom concreted level with the top of the flanges. With overhead purifiers it is usual to have the bottom flanges external. Luteless Purifier Covers or Lids are constructed of an outer curb of angle steel with cross members of H or T steel and the whole covered with steel sheets generally J in. in thickness, securely riveted to the curb and the cross members. They are usually made between 10 and 15 ft. square, there being a number of such covers to each purifier, determined by the size of the latter ; each being provided with lugs to which chains are attached for raising and lowering. The space between the lids and between the lids and the outer edge of the purifier is covered by cast-iron plate gangways 2 or 3 ft. wide. To the lower side of the angle steel curb on the cover, various arrangements of indiaTrubber jointing, about 2j in. wide by J in. thick, are secured ; and the rubber, when the cover is down on the purifier, rests upon the planed edge of the gangway. To prevent the cover from lifting when the gas is turned into the purifier, lugs and fastening arrangements are placed round the cover for securing same to the gangways. These flatten out the india-rubber and so secure a gas-tight joint. The holding down catches, where no special automatic arrange- ment is used, are generally formed of eye-bolts which fit into slots made in the cover. The better arrangement, however, and especially for large covers, are the automatic catches, which are all operated simul- taneously, releasing the cover by one movement. The " Eclipse " patent fastener of Clapham Brothers and Milbourne's automatic rapid cover fastener are designed for this purpose. Sieves, Trays, or Grids. The arrangements inside the boxes for the purpose of supporting the grids depend upon the type of grid to be adopted. For horizontal wood grids, ribs are cast on the 1 68 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS inside plates of each purifier in either two or four tiers, and cast-iron standards are fixed inside the purifiers for the purpose of supporting the T-steel bearers on which the grids rest. With vertical or hurdle grids it is usual to make provision- for one or two tiers of ordinary grids on which the former rest. For horizontal grids, round wrought-iron rods, f of an inch thick, bound together with a framing of angle or flat iron, make an excellent grid, especially where lime is used ; they are less suitable for oxide of iron, which destroys them by corrosion, though when made of the strength named, they last for many years. They possess a great advantage over most other grids in the smaller space which they occupy in the purifier and the larger purifying area obtained by their use. Perforated cast-iron and wood grids are suitable for either lime or oxide. The latter are usually made with strips of wood (yellow pine, pitch pine, or red deal, the prices being as 3, 2, i) of any convenient length. The strips are 1 1 in. broad, J in. thick, and slightly tapered, the outer pieces or frame being of harder timber (hickory, beech, oak, or ash), and ij in. thick ; the whole bound together with f-in. bolts and nuts, having the heads, washers, and nuts countersunk in the side frames, and the holes plugged with wood or cement. The strips are kept j in. to f in. apart by pieces of wood of that thickness, and i| in. square, put between them at the places where the bolts are inserted (Fig. 96). The " hurdle " form of grid is now being ex- FIG. 96. tensively used, the advantages claimed being that a larger quantity of purifying material can be utilized in the same area afforded by the horizontal grid ; and also that the purifying material is suspended in thinner bulk, thus minimising the back pressure given by the plant. The " Jager," " Cutler," Spencer's " Hurdle " (Fig. 97), and the " Standard " of Kirkham, Hulett, & Chandler, rank foremost of the new forms. Rule for the Size of Purifiers. The capacity or purifying power of the vessels is determined more by their superficial area PURIFIERS 169 than by their cubical volume. There is, however, a mutual relation between the two, as, when the depth is increased and fully utilized, the surface area has to be proportionately augmented, on account of the resistance offered by the deeper material to the flow of the gas. It is more strictly correct, then, to say that the superficial area, in pro- portion to the depth of the purifying material, is the gauge of the capacity or purifying power of the vessels ; FlG 97 and the maximum hourly or daily gas-make of which the works are capable should form the basis of any calculation to determine their size. One of the chief conditions for securing satisfactory purification is the use of vessels of large area. If economy and efficiency are to be considered, time is an important element, and must not be disregarded. The mere passing of the gas through the puri- fying media is not sufficient in itself to insure good results ; time, or, what is the same thing in this case, lengthened contact, is required for chemical affinity to operate. Therefore, in determining the size of purifiers, where either lime or oxide of iron is intended to be used, it is of the utmost importance to provide a liberal superficial area, and to make ample allowance for increased gas-make. One of the greatest sources of discomfort to a gas manager is ha^ng his purifiers so cramped and confined in their area as to be incapable of doing the work required in an efficient manner. Where it is intended to have four purifiers, three always in action, the maximum daily (twenty-four hours) make of gas. expressed in thousands, multiplied by the constant O'6, will give the superficial area in feet of each purifier. Example. Required the superficial area of each of the four purifiers in a works equal to the production of 500,000 cub. ft. of gas per diem of twenty-four hours. 500 x 0'6 = 300 ft. superficial area of each purifier. Y/3OO = 17-3 (say 18) ft. side of square of purifier. For very small works where there is no exhauster, the constant 0'8 may be employed with advantage. 170 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Water Lutes. The evils of contracted area in purifiers are aggravated by having a shallow seal to the lids or covers and the hydraulic centre valve if such be used. In small works the lute should never be less than 12 in. deep by 4| in. wide ; and in medium-sized and large works, from 18 to 30 in. in depth by 6 to 8 in. in width. Ample depth of water lute is especially important where the back-pressure is increased by the use of telescopic holders. Layers of Purifying Material. In purifers with horizontal grids charged with hydrate of lime, there may be two or four tiers of sieves. The lime spread upon their surface may be from 4 to 8 in. in depth. When oxide of iron is used, the layers may be two in number and the material 15 to 20 in. deep on each. It is a mistake to adopt the plan of placing either the lime or oxide in a single" deep layer. The gas is apt to form passages through the deep material ; whereas when there are two or more layers of less depth, it recovers itself and changes its course through each. Apparatus for Raising the Lids or Covers. For raising the lids or covers of water-luted purifiers various contrivances are employed, the most common being a double purchase crab, travelling on rails laid on either wooden beams or iron lattice girders, having their ends inserted in the walls of the building, or in the absence of walls, supported on pillars. Another arrangement consists of a traveller extending across the purifying house from wall to wall, traversing the length of the house on rails fixed on each side to a beam or girder supported by projecting corbels. On this again there is a lifting crab also on rails, and the gearing of both crab and traveller is actuated by chains from the floor of the house. The lifting machine, sometimes called a " Goliath " (Figs. 94, 95, and 98), first constructed by Cockey & Sons, is a useful and compact contrivance for the same purpose. This consists of two standards, one on each side of the purifier, connected across the top by two .girders a few inches apart. The standards, having grooved or flanged wheels or rollers attached, traverse the purifying house from one end to the other on rails on the floor. The covers are raised by means of two long vertical screws, with an eyelet-hole at the end of each, in which the hooks on the lid are inserted, and moved by a winch and cog-wheels put in motion by a handle PURIFIERS 171 at one of the sides. When the apparatus is not in use, it can be wheeled out of the way, leaving the space above the purifiers, to the tie-rods or beams of the roof, entirely unobstructed. A somewhat simi- lar traveller, in which hydraulic power is applied instead of the wheel gearing and screws, is sometimes employed for accomplishing the same object. A compact and efficient lifting arrange- ment for lids of large size is that of the direct-acting hydraulic ram, the head of which is attached to the centre of the lid, and on the application of water pressure to the ram by means of a hand or steam pump, the lid is raised to the required height (Fig. 99). FIG. 98. By adopting the luteless system of purifier construction heavy machinery for raising the covers of large purifiers is FIG. 99. dispensed with, a simple arrangement of lifting gear only being required. Various contrivances are employed, the most common being a 172 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS pulley-block with travelling carriage running on the bottom flange of a rolled-steel joist supported on steel stanchions. Another arrangement is a light jib or double jib travelling crane running on rails fixed on the top plates or gangways of the purifiers. The " Goliath " (Fig. 95) is also a useful and compact contrivance for the same purpose. Centre and Other Change Valves. The round dry centre valve (Fig. 100), with surface faced to fit gas-tight, is now extensively adopted, and, as a rule, is preferred to the old hydraulic centre valve. The chief advantages it possesses over the latter are the greater ease and facility in changing from one purifier to another, one man FIG. ioo. FIG. 1 01. being able to accomplish this with a few turns of a handle, thus minimizing to the utmost extent the passage of unpurified gas during that operation. It oc- cupies less space, is entirely be- neath the purifying-house floor, and presents a dead resistance to pressure, admitting of greater steadiness in the flow of the gas where an exhauster is at work. But it has its drawbacks. In the larger sizes especially it is liable to lose its tightness on the slightest disturbance of the foundation either by subsidence or the action of frost, and even by the weight and pressure of the connecting pipes. The Week valve (Figs. 101 and 102), which FIG. 102. CHANGE VALVES 173 consists (for a set of four purifiers) of eight valves within a frame or box, is both handy and efficient, and for large connecting pipes is preferable to the foregoing. Four-way valves are adopted by some managers in preference to the centre valve, their chief recommendation being that by their use the connections are simplified. The advantages which they possess over the ordinary single valve are more apparent. When the latter are employed, twelve are needed for a set of four purifiers and six for a set of two ; whereas with the four-way valves only one-third that number is required. The hydraulic valves, made specially for purifiers, by Samuel Cutler & Sons, and the " Eclipse " hydraulic centre valve of Clapham Bros., whilst possessing the simplicity in working of the dry-faced valve, have the further advantage of being perfectly gas-tight, no matter what the size of the valve may be. Both these valves are worked by the manipulation of a water supply. The " Eclipse " hydraulic centre valve is cylindrical in form, with internal compartments formed by concentric and radial cast- iron plates. The water supply is under the control of a patent water-feed and draw-off valve. By turning the index handle of the water valve to the different positions marked on the face, it is possible to work the purifiers with the following changes : First, any purifier alone ; second, any two or three purifiers in juxtaposition to one another ; or, third, all four purifiers on. Connections. With respect to the size of the connecting pipes, the rule is to make their internal diameter, in inches, equal, as nearly as possible, to the square root, in feet, of the area of the purifiers. Thus, purifiers 10 ft. square, giving an area of 100 sq. ft., have connecting pipes 10 in. in diameter, and purifiers 16 ft. by 12 ft., having an area of 192 sq. ft., have their connecting pipes 14 in., in diameter. With the larger proportionate sizes of puri- fiers now being employed over those formerly erected, a deduction of J may safely be made from the result obtained by the above rule. Thus (see rule on p. 169) a works capable of producing 500,000 cub. ft. of gas per day requires four purifiers, having each an area of 300 sq. ft. [500 xo'6 = 300], the square root being 173 ; deducting J, or 2'2, we have 15-1, or, say, 15 in., the diameter of the connecting pipes. Within recent years there have been brought out two or three 174 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS patents, notably by C. & W. Walker and Willey & Co., whereby the connections between the purifiers are either considerably reduced or altogether dispensed with. In Messrs. Walker's arrangement the connections, what few there are, may be in the form of a rectangular box passing beneath the gangways, on the sides of the purifier, or beneath the same, each purifier being worked by means of special disc-valves. These are chiefly advantageous with the luteless type of purifiers, as in such cases advantage is taken of the several purifiers being in juxtaposition with each other. Notes on Lime. Limestone is calcium carbonate found in its natural state, from which the calcium oxide (quick or caustic lime) is produced by the expulsion of the carbon dioxide by means of heat in the lime kiln. Quick or Caustic Lime (calcium oxide) is lime in the solid state before absorbing or being slaked with water. Hydrate of Lime is a chemical compound of lime and. water in the proportion of one part of water to three parts of lime. M ilk of Lime or Cream of Lime is a mixture or solution of hydrate of lime and water. Quicklime nearly doubles in bulk on being slaked. From 90 to 140 Ibs. of quicklime, reduced to the hydrate, are re- quired in the purification of the gas produced from one ton of cannel, and from 55 to 80 Ibs. of that produced from one ton of coal. I bushel of quicklime weighs about 70 Ibs. i cubic foot of - 54 i cubic yard of 1460 i ton of is equal to about 32 bushels. The value of lime as a purifying agent is in inverse proportion to the amount of earthy or foreign matter it contains ; that which leaves the smallest proportion of insoluble sediment on being dissolved in diluted acid is the best CLASSIFICATION Of the best-known Limestones of this Country, in the order of their Purity, and which Order also expresses their Value for the purpose of Purifying Coal Gas. (Hughes.) i. The white chalk limestone of Merstham, Dorking, Charlton, Erith, and other parts of the chalk range surrounding the Metropolis. LIMESTONES 175 2. The grey chalk limestone, from the lower beds of chalk. 3. The blue beds of the upper and middle Oolites. 4. The lower white and grey limestones of the Oolites. 5. The most calcareous and crystalline beds of the carboni- ferous or mountain limestone, colours grey and bluish. 6. The magnesian limestone of Yorkshire and Derbyshire. 7. The white lias limestone. 8. The blue lias limestone. 9. The Silurian limestone of Wenlock, Dudley, etc., and the coralline limestones of Plymouth and the neighbourhood. TABLE Showing the Composition of Different Limestones and their Specific Gravity. (Government Commission.) Quality of Limestone and Locality. Carbonate of Lime. Carbonate of Magnesia. Silica (Flint). Iron Alumina (Clay). Water and Loss. Specific Gravity (Dry). JAncaster, Lincoln- shire 93'59 2-90 0-80 | 2-71 2-182 Bath Box, Wilt- shire . . . 94- 52 2-50 I'20 1-78 1-839 =3 Portland, Dorset- shire . 95-16 I'20 I'2O 0-50 j 1-94 2-145 Ketton, Rutland- shire . 92-17 4-10 0-90 2-83 2-045 /Barnack, Northamp- Jtonshire 93'40 3-80 1-30 ! 1-50 2*090 IChilmark, Wilt- i s'} shire . S Ham Hill, Somerset- 79-00 3-70 10-40 2'00 4'20 2-481 - 1 \ shire . 79' 30 5-20 4-70 8-30 i 2-50 2-260 A trace of bitumen was observed in each of the above. Bolsover, Derby- j shire . . . 51*10 40-20 3-60 1-80 3-30 2-316 |S* Huddlestone, York- 's -S j shire . |S1 Roche Abbey, York- 54-I9 41-37 2'53 0-30 1-61 2-147 g-J shire . 57*50 39'4Q o'8o 0-70 1-60 2'i34 Park Nook, York- " shire . . 55-70 41-60 ~~ 0-40 2-30 ! 2-138 176 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Other Analyses. Quality of Limestone and Locality. Carbonate of Lime. Carbonate of Magnesia. Silica (Flint). Iron Alumina (Clay). Water and Loss. Analyst. .Dp.nton near York . 6ro 3O'O 2"2<\ 0'2S Holme ,Denton, near York . 63*0 30 o 2-25 C MAIN PIPES 241 in inclined moulds. The pipes should be tested by hydrostatic pressure equal to at least 75 Ibs. on the square inch (173 ft. head of water), either at the place of manufacture or on the gas-works ; and whilst under "pressure they should be smartly rapped with a 3-lb. hammer from end to end. This will often reveal faults, such as sandy, porous, and blown places, not otherwise discernible, Rapping the pipes whilst on the ground will also indicate their character. If the sound emitted is clear and bell-like, the pipe may be considered free from defects. On the other hand, if dull TABLE. CAST-IBON GAS PIPES, WITH OPEN JOINTS. The weight of the socket, and bead on spigot, is equal to 9-10tfw jf a lineal foot of the pipe, and this is included in tJie weights given. Internal Diameter ct Pipe. Thickness of Metal in Body of Pipe. Length of Socket, insida measure. Length of Pipe, not including Socket. Weight per Pipe, inclusive of Socket and Bead. Inches. Inches. Inches, Feet. Cwts. qrs. Ibs. 1 5-16ths 24 6 010 i* 5-16ths 2i 6 1 10 2 6-lGths 3 6 1 22 2 8-8ths 3 6 2 17 3 3-8ths 3 9 1 11 4 3-8ths 9 1 1 19 5 7-16tha 9 207 6 7-16ths 9 2 1 21 7 5-10ths 9 3 27 8 5-10ths 9 3 2 19 9 6-10ths 4J 9 4 11 10 9-16tha 4i 9 5 16 11 9-16ths 4* 9 5 2 14 12 6-8ths 4| 12 8 3 16 13 6-8ths 44 12 9 2 12 14 ^ 5-8ths 44 12 10 1 8 15 6-8ths M 12 11 4 16 ll-16ths 4* 12 12 3 24 17 ll-16ths 3 12 13 2 24 18 ll-16ths 4 12 14 2 19 3-4ths 4| 12 16 2 24 20 3-4ths *i 12 17 2 8 21 3-4ths 5 12 18 1 20 22 13-16ths 5 12 20 3 20 23 13-16tha 5 12 21 3 8 24 7-8ths 5 12 24 2 8 30 1 6 12 35 36 IJth 6 12 47 16 42 1A*I 6 12 57 3 16 48 lith 6 12 69 2 242 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS and leaden, it is cracked or otherwise imperfect. All pipes that do not stand the tests should be rejected. The metal of pipes, whilst compact and close, should not be excessively brittle and splintery, but such as may be readily chipped and drilled. Cast-iron pipes below 3 in. diameter are 6 ft. long ; 3 in. to TABLE. CAST-IRON GAS PIPES, WITH TURNED AND BORED JOINTS, HAVING A RECESS IN FRONT FOR LEAD. The iveight of the socket and thickened spigot is equal to Ij 1 ^ lineal foot of the pipe, and this is included in the weights given. Internal Diameter of Pipe. Thickness of Metal in Body of Pipe. Length of Socket, inside measure. Length of I ipe, not including Socket. Weight per Pipe, inclusive of Socket and thickened Spigot. Inches. Inches. Inches. Feet. Cwt. qrs. Ibs. 1 5-16ths 21 6 1 1 li 5-16tbs 21 6 1 12 2 6-16ths 3 6 1 24 21 3-8 th s 3 6 2 19 3 3-8ths 3f 9 1 14 4 8-8ths 4 9 - 1 1 22 5 7-16ths 4 9 2 13 6 7-16ths 4| 9 2 1 27 7 6-10tbe 4$ 9 318 8 6-10ths ii 9 330 9 5-lOths 9 4 23 10 9-16ths 41 9 510 11 9-16ths 4 9 5 3 1 12 5-8fchs 41 12 904 13 6-8ths 41 12 930 14 5-8ths 4 12 *10 1 24 15 5-8ths 5 12 11 24 16 ll-16ths 5 12 13 16 17 ll-ietha 5^ 12 13 3 20 38 ll-16ths 6* 12 14 2 24 19 3-4ths 6* 12 16 3 24 20 3-4ths 5| 12 17 3 12 21 3-4ths 12 18 2 24 22 13-16ths 5 12 21 1 23 13-16tbs 5j 12 22 20 24 7-8ths g| 12 24 3 24 30 1 5^. 12 35 2 4 36 Hth 6 12 47 3 16 42 l^ths 6 12 68 3 4 48 lith 6 12 70 2 8 MAIN PIPES 243 FIG. 136. TABLE. Dimensions of the Sockets of Turned and Bored Cast-iron Gas Pipes, with a recess in front. (Fig. 136.) TABLE. Dimensions of the Sockets of Turned and Bored Cast-iron Gas Pipes, without a Recess in Front. (Fig. 137.) Diameter of Pipe. A B c D E Diam. of Pipe. A B C D Inches. Inches la. In. In. In. Inches. Inches. Inches. Inches. Inches. 2 5-16ths it i 3 I 2 5-16ths I i 3 24 3-8ths A 3* II 2J 3-8ths II A 3i 3 3-8ths if i 3| i 3 3-eths 1 8| 34 3-8ths 1 ! 8| 3J 3-8ths li | S 4 8-8ths IA ii 4 il 4 3-8ths li H 4 5 7-16ths u U 4 il 5 7-16ths 1| i* 4 6 7-16ths ii 44 1 6 7-16ths li 4i 7 5-10ths IA | 44 1 7 6-10ths IA f 4J 8 6-lOths it if 44 IA 8 5-lOtha if It 44 9 5-lOths it 44 IA 9 5-lOths in 4i 10 9-16ths IA | 44 IA 10 9-16ths ii i 4i 11 9-16tha 14 il *i u 11 9-16ths IH i l l 44 12 5-8tha ij if 4J H 12 5-8tha lit if 4| 13 6-8tbs IA i* 44 H 13 5-8ths ii il 44 14 5-8tha IA il 4* H 14 5-8ths ii II 4i 15 5-8ths if l 5 IA 15 6-8ths 2 1 5 16 ll-16tha IH l 5 IA 16 ll-16ths 2 1 5 17 ll-16i h3 if IA 6* li 17 Il-16th8 2J IA 64 18 H-lGth3 in IA 5* 11 18 ll-16ths 2* IA 6J 20 3-4ths IH n 6* IA 20 3-4ths 2i ir 6| FIG. 137, R 2 244 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS ii in. diameter, 9 ft. long ; when 12 in. diameter and upwards they may be either 9 ft. or 12 ft. long. The socket is not included in these lengths. TABLE. OAST-IKON GAS PIPES, WITH FLANGE JOINTS. The weight of the flanges is equal to 1 lineal foot of the pipe, and this is included in the weights given. Flanges. Internal Diameter of Pipe. Thickness oi Metal in Body of Pipe. Dia- meter across Flanges Thick- ness of Metal. Numbei of Bolt Holes. Dia- meter, centre to centre, of Bolt Dia- meter of Bolts. Length of Pipe outside the Flanges. Weight per Pipe inclusive of the Flanges. Holes. \ Inches. Inches. Inches. Inches. icbcs. Inches. Feet. Cwts. qrs. Ibs. 1 5-16ths 4 T 7 * 3 2 T^ 6 1 M 6-16ths 4* A 3 ya 6 1 11 2 5-16ths 6J 4 *i rV 6 1 22 2i 3-8 ohs 7i A 4 5J G 2 18 3 3-8ths 74 Vi? 4 5* | 9 1 11 4 3-Sths 9 T H ,T 4 7 | 9 1 1 22 5 7-16ths 10J 4 8J | 9 2 10 6 7-16ths lli 6 4 9i 9 2 1 24 7 6-10ths 13 I 4 11 I 9 815 8 5-10ths 144 6 12 9 8 2 25 9 5-10ths 16 .3 6 13i | 9 4 17 10 9-16ths 17i | 6 14| | 9 6 22 11 9-16ths 181 | 6 J5| 9 5 2 20 12 5-8ths 19* if 6 16i f 12 8 3 24 13 5-8 ths 204 is 6 174 12 9 2 20 14 5-3ths 214 1 8 isi | 12 10 1 16 15 5-8ths 224 1 8 19i 12 11 12 16 ll-16ths 24 IA 8 21 I 12 13 8 17 ll-16ths 25 ] iV 8 22 12 13 3 8 18 ll-16ths 26 H 1) 23 I 12 14 2 12 19 3-4ths 27 H 10 24 i 12 16 3 12 20 3-4ths 28 14 10 24i | 12 17 2 21 21 3 4ths 29 14 10 25J | 12 18 2 8 22 13-16ths 30 IA 10 26J I 12 21 8 23 13-16ths 31 li 10 * 27i 12 22 24 7-8ths 32 IA 12 234 I 12 24 3 30 1 38 1^ 14 34 1 12 35 1 36 llth 45 li 13 41 A 1 12 47 2 42 lAths 51 ig 20 47A 1 12 58 1 8 48 Ijtfa 57 If 24 63i 1 12 70 4 Cast-iron, in cooling from the molten condition, shrinks j of an inch per foot. MAIN PIPES 245 Formula for calculating the weight of cast-iron pipes W-2-45 (D~ d*). Where D = outside diameter of pipe in inches. d = inside diameter of pipe in inches. W = weight of a lineal foot of pipe in Ibs. It is usual to pay for any overweight in the pipes beyond the weight specified, not exceeding 4 per cent. For the smaller sizes of pipes up to 8 in. diameter, the open jointing space is f in., and for larger diameters J in. wide all round. The following are the usual depths of the socket, inside measure, for the various sizes of open-jointed gas-pipes, plugged with yarn and lead : Diameter. Depth of Socket. Up to 3 inches 3 inches. 4 to 8 4 9 to 20 4J 21 to 30 . 5 32 and upwards . . . ;" . . 6 When the turned and bored joint, on being tested, is found gas- tight, it is not necessary to fill the recess with lead. The usual filling material adopted under such circumstances is Portland or Roman cement. These cements, if kneaded with warm water, set quickly * with cold water, not so soon. Main Pipe Joints. A host of joints for main pipes have been invented from time to time, which, though theoretically good, have not all proved satisfactory in practice. The classes of joint generally in use are the turned and bored, and the open joint. The ball and socket joint is employed under exceptional circum- stances, as when the main has to be laid in the bed of a river or harbour, or across a narrow arm of the sea. A difference of opinion exists among engineers as to which form of joint is best the turned and bored, or the open joint filled with lead, r rust cement, or other substance, metallic or otherwise. We, who have had large experience in both, and under most circum- stances, prefer the turned and bored, alike for ease in adjustment, economy, and efficiency. In districts where the ground is extensively undermined and HableTto subsidence, the vulcanized india-rubber joint (which is virtually fan open joint) is the most suitable (Fig. 141). Special pipes, such as r bends, tees, and junctions, are, for convenience sake, made with open joints (Fig. 144). 246 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS The turned and bored joint is shown in Fig. 138. There is no difficulty in swinging round ordinary curves with a line of mains jointed in this manner ; but when the radius of the curve is short, an occasional yarn and lead joint is required. In specifying for pipes with these joints, care should be taken that the bored and turned surfaces are not made with too much taper ; indeed, the nearer the surfaces approach to parallel lines without being absolutely parallel, the better they will fit. The socket may either be bored flush up to the face, as in Fig. 137, or it may have a recess in front, as in Figs. 136 and 138. The latter is to be preferred, as it can be supplemented with lead or other filling should the turned joint prove defective. Two examples of the open joint are given in Figs. 139 and 140. FIG. 138. FIG. 139. FIG. 140. The india-rubber joint (Fig. 141) is formed by passing a vul- canized ring of that material round the spigot end of the pipe, which is specially cast with a groove and bead to suit this de- scription of joint. When the pipe end is pushed forward into the socket, the ring is compressed or flattened, and butts against the raised bead. No other packing is necessary, so that it is an expeditious method of jointing, whilst the vulcanized india-rubber, unaffected by the presence of gas or moisture, is practically inde- structible. The other advantages of this joint have already been referred to. The ball and socket joint is shown in Fig. 142. This particular form is the invention of Mr. J. Z. Kay, and has been successfully employed for main pipes crossing through rivers and harbours where the ordinary rigid joint is inapplicable. The lead is first run in and caulked ; and the connected pipes, being like a chain, can be paid out of a lighter or other vessel, when they will find their own bed in the river bottom. The expansion joint (Fig. 143) is useful in all cases where a line of main is exposed to varying temperatures, as in pipes MAIN PIPES 247 placed against a wall or alongside a bridge, or in an open trench or channel. Mill-board or engine-board, coated with red or white lead, makes a good and durable joint for flanges not under water. FIG. 141. FIG. 142. FIG. 143. A combination of asbestos and india-rubber woven sheeting makes a superior flange joint, especially for steam purposes, as these substances resist the action of both heat and moisture. To prevent adherence to the iron (in the case of blank-flange and manhole joints that require to be frequently broken), the flange should be rubbed over with powdered black lead before placing the cover. Metallic rings are best for flange joints. These may be made with J in. or f in. lead pipe, with the ends soldered evenly to- gether ; the ring is then covered with flax, and well smeared with red lead or paint. The pipe must not be beaten flat, but left round, with a few gimlet holes bored in it to allow of the exit of the air, so that when the joint is screwed up it may bed into any irregulari- ties in the surfaces. The remaining space between the flanges is rilled with rust or other cement. Flange pipes can be jointed without the interposition of any packing material, by having the flanges faced in a lathe. In such case the surfaces are merely coated with white lead paint, and the joint tightened up. Bolts used for jointing flanges, etc., should have a gummet oi flax or tow, smeared with red or white lead, placed round theii neck and behind the washer at the nut end, to bed under the head and nut when screwed up. Red and white lead should always be mixed with boiled linseed oil. Other oil can be made to answer, but not nearly so well. The bends, tees, junction pipes, and other irregulars required in the distributing department, are shown in Fig. 144. 248 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Gas pipes should be free from excrescences, and moderately smooth on their inner surface. They are better not coated internally with any kind of sub- stance soluble in naphtha or other hydrocarbon liquid. Such coating is soon dissolved by the gas, and drains partially away into the drip wells ; the residue collecting into viscid masses at different points, principally near to. the joints. The coating can only be intended to reduce friction by rendering the surface smooth for the passage of the gas, because as a preservative to the iron, internally, it is not required. Its effect is to impede the flow. The slight deposit which takes place from the gas alone soon gives the metal a smooth coating. These objections do not, of course, apply to the internal coating of water pipes. It is only for appearance sake, as a rule, that a covering of this description can be recommended for the outside of cast-iron pipes. It often serves only to hide defects in the casting. The reddish brown oxide covering which cast-iron pipes acquire in a short time, when laid in ordinary soil, is one of the best pre- servatives of the metal. This covering is impervious to moisture, its effect being to arrest further corrosive action. There are, however, circumstances where it is desirable and necessary to coat pipes externally, as for example, when they are of wrought-iron, and when, though of cast-iron, they are to be laid in soils intermixed with engine ashes, furnace slag, vitrified cinders, clinker, dross, scoria, or chemical refuse of any kind. Wrought=lron and Steel Main Pipes. Of recent years wrought-iron and steel main pipes have been largely adopted. The advantage that wrought-iron and steel possess over cast-iron is due, primarily, to their much higher tensile strength and greater ductility ; hence the tubes may be made thinner. This advantage is also accompanied by economy in the cost of laying and subsequent maintenance ; the former being due to the long lengths obtainable (40 ft.) and the consequent fewness of joints, and the latter to the absence of breakage. A further advantage is that the smaller sizes of these mains can be bent cold in situ ; thus minimizing the use of special bends. Since the advent of the Mannesmann weldless steel tube, first made on the Continent, and now in this country, the use of this type of tubing has made rapid progress, especially in the direction of high-pressure distribution. MAIN PIPES 249 250 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS This tubing is made with a number of different joints ; Fig. 145 shows the ordinary joint, corresponding to the open joint in cast- iron pipes. The rigid joint is used (Fig. 146) where the main is subject to vibration, or the ground liable to subsidence. FIG. 145. FIG. 146. The socket in the rigid joint is expanded in two stages, the inner portion being of diameter sufficient only to take the spigot, and the outer portion, which is of larger diameter, is utilized for the jointing material. The object of this joint is to make the tube a homogeneous length ; the jointing material serving only to prevent leakage, whilst the vibration is transmitted direct from pipe to pipe. An improved form of rigid joint has been devised in which the spigot, so far as it enters the inner sleeve, is slightly expanded so as to form a shoulder, which, pressing on the.packing, prevents drawing. The jointing is effected in the same way as with cast-iron pipes. Wrought-iron and steel mains are also made lap-welded and riveted, and with flanged or screwed and socketed joints. Thickness and Weight of Wrought-iron Main Pipes. Diameter Inside. Thickness. Weight per Foot. j Inches. Inches. Pounds. 3 5 5 2 full. 6 3* ~5V 7 4 A 9 5 A I0| 6 I 3 * 13 7 \ bare. 18 8 20 9 " t 24i 10 28 12 33 14 i 5 s 43 16 ft 50 MAIN PIPES 251 05 I ^ > 00 ON V t --- . % V S i. & ? 10 vO * 2 He^N** ! cr > | -< 10 M CO | ***%& z vav^e'-s Interna Thickne Length Length Diamet Packing 252 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS The smaller sizes, 3 in., 3^ in., and 4 in. diameter, have screwed ends and sockets. The larger diameters may be either screwed, socketed or plain. In the latter case the " Kimberley " collar (Fig. 147) is] employed^ for connecting them ; this ^is 'also made of wrought-iron. Weight of Lead required for Jointing Wrought-iron Main Pipes with the " Kimberley " Collar. Internal Diameter of Pipe. Depth of Lead on each side of Collar. Weight of Lead. Internal Depth of Lead Diameter on each side i of Pipe. ! of Collar. Weight of Lead. Inches. 6 I 9 Inch I; I; I; I; I; es. j Pounds. Inches. Inches. 8| 10 ij 10 II if III 12 If 13* 14 2 15 ;| 16 | Pounds. i|* 18 20 26 30 All wrought-iron and steel mains should be protected on the out- side with some form of impervious covering to prevent corrosion. The connection of branch pipes to these is a matter that has claimed special attention on account of the thinness of the metal. Various connections have been devised chiefly by the use of clamps or clips. An ingenious device is the " expansion nipple," patented by Woodall & Parkinson. This consists of a short length of steel tube of the barrel nipple type, and has an internal annular bead at the lower end about T V in. in thickness. The lower end is screwed into the main, which is drilled and tapped in the usual way. A tapered mandrel is drawn through the nipple and expands the annular bead, thus riveting the nipple on the inside of the main. An expansion nipple and ferrule have also been devised for high-pressure tapping. The Laying of Main Pipes. Special care is needed in the laying of main pipes. As a general rule the covering of soil over them should be at least 21 in. deep, to protect them from FIG. 147. MAIN PIPES 253 breakage by steam rollers, the influences of heavy traffic and low and varying temperatures. The risk of breakage by steam rollers does not apply to steel mains ; hence the excavations need not be quite as deep. The covering, however, excepting under special circumstances, should not be less than 18 in. The excavation to receive the pipes should not be unnecessarily wide, as the less filling up that is required the better, not to mention the saving in cost. The bottom of the trench on which the pipes rest should be even and firm, and if not so, then thoroughly consoli dated by punning. The soil should be scooped out at the various points in the trench bottom where the sockets come, so that the body of the pipe may lie solid throughout its length. In cases where this cannot well be done, resort may be had to underpinning. Each pipe should be laid with the proper inclination or fall, and securely jointed ; all joints being proved either with gas or air under high pressure while the trench is open. In roads or footpaths made with ashes or chemical refuse, the ; pipes should be carefully embedded in good common soil obtained for the purpose, or puddled round with clay especially protecting the upper side with a thick covering. It is worse than useless to place clay only underneath the pipe. When so placed, it serves to receive and retain the water, which, percolating through the material forming the ground, is charged with acid bisulphides and other deleterious compounds. The metal of the pipe thus lying, as it were, in a bath of acidulous liquid, is destroyed sooner than it would be if no clay were present. The protection afforded by the clay should therefore be complete, all round the pipe, and particularly over its upper surface. In refilling the trench, the soil should be shovelled in in layers, and rammed firmly and equally all round and above the pipes. Gas pipes laid through arable land do it no harm, but rather good, inasmuch as they help to drain the land. The joints should be perfect, however, as the escape of any gas is fatal to vegetable life. When laying pipes with bored and turned joints, the spigot and socket ends, after being cleaned with cotton waste, are coated with thick paint composed with one part each white and red 254 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS lead mixed with boiled linseed oil. The end is then inserted and driven home with a mallet, or, should the pipe be large, with a swing block. Or another pipe swung from the shear-legs may be used. In this case a wood shield should be laid against the socket to take the force of the blow. In driving the pipes, they will sometimes be found to spring back at every stroke. This may be due either to the surfaces being made too conical, in which case it is difficult to ensure a good joint ; or there is a slight ridge or roughness on the inner edge of the bored part of the socket. Chip off with a sharp chisel. Red lead sets sooner and harder than white, and the follow- ing reason is given for preferring the white to the red for joints : When any expansion or contraction takes place in the pipes, the red lead is liable to crack, and so cause a leakage ; whereas the white lead is more tractable, and better adapts itself to the varying circumstances. An equal mixture of the two is preferable. In placing pipes with open joints, twined gasket is caulked in all round so as to fill nearly half the length of the open space. A roll of tough plastic clay is then passed round and pressed against the socket face, and through a lip on the upper side molten lead is poured till the remaining space is filled. On the lead being set up with a blunt caulking tool and hammer, the joint is complete. The ladle should contain sufficient molten lead to fill the joint at one pouring, otherwise the adhesion of the metal throughout will not be perfect. Molten lead, when heated to redness, will fly when poured upon a wet or damp surface. Mains in level ground should be laid with a slight inclination, say i ft. in 400 yds., and at each lowest point a syphon or drip-well (Fig. 148), of cast-iron, should be placed underneath, and connected by a tube to the pipe to receive the liquid arising from condensation. Another form of syphon, with sockets to receive the main pipes, is shown in Fig. 149. In all cases where a main dips, a syphon is required at the place where the dip is reversed. The liquor from these receptacles is pumped out periodically into a cask on wheels, and deposited in the tar well on the gas- works. In laying down mains in lieu of others of a smaller size, the MAIN PIPES 255 difference in value between the two sizes of pipes only should be charged to capital account. For pipes i| to 8 in. in diameter the lead is assumed to be about f in. thick ; and in pipes 9 in. in diameter and upwards, J in. thick. In place of molten lead, lead wool, rust cement, and a mixture of beeswax and tallow are used for jointing mains. FIG. 148, FIG. 149. TABLE. Giving the Weight of Lead in Pounds required for Jointing Cast-Iron Mains. I Diameter Depth of Weight of of Pipe in Lead in Lead in Inches. Inches. Pounds. Diameter of Pipe in Inches. Depth of Weight of Lead in Lead in Inches. Pounds. ii u .* ii 2i X6* 2 I I J f 12 2f 18* 2^ I 2i 13 2| 21 3" I 2 f 14 2 23* 4 i; 4 15 2 l 26 5 ii 16 2* 28* 6 2 7 17 2* 3l" 7 2 8 8| r ioi 18 19 2| 32* 2 34 9 2 I2 i 20 2ff 35* 10 2; r 14* 24 3 48 Iron or Rust Cements for Flange and Open Socket Joints. (i) i Ib. of clean iron borings, pounded fine in a mortar. 2 oz. sal ammoniac (muriate of ammonia) in powder, i oz. flowers of sulphur. NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Mix the whole together by pounding, and keep dry. For use, mix one part with twenty of iron borings pounded, adding water to the consistency of mortar. (2) 98 parts fine iron borings. i part flowers of sulphur. I part sal ammoniac. Mix, and when required for use, dissolve in boiling water. This cement sets quickly. If required to set slowly, which makes the better joint (3) 197 parts iron borings. 1 part flowers of sulphur. 2 parts sal ammoniac. When required for use, mix with boiling water. The iron borings used for making joints should be perfectly free from grease and oil. The cubical content of the joint in inches, divided by 5, gives the weight in pounds of iron cement required. Lead -Wool. The advantage of this joint depends more on the skill of the workman than on the material used. It is invariably employed in the jointing of steel mains owing to the sockets being able to withstand the caulking strain. In caulking with lead-wool, a 4-lb. hammer is usually employed, the object being to caulk the lead strand by strand as tightly as possible. Appliances used in Mainlaying. In beginning to lay an extensive length of main pipes, considerable delay, and con- sequent loss, is often experienced at first, owing to a want of foresight in providing beforehand the necessary men, tools, and other appliances required. The following is an enumeration of what is necessary to be provided, varying according to the peculiarities of the district and the extent of the work to be done : One or two skilled mainlayers. A number of labourers according to the extent of the work. A pavior and his labourer. A night watchman. A pick and spade (and a tool, if clay) for each labourer. A supply of picks, pick handles, and wedges should be kept in stock, to replace broken ones. A screen for separating stories and soil. Shear-legs or tripod ; or, what is better, if the mains are of MAIN PIPES 25? large diameter, a movable pipe-layer, supported on wheels, running on rails laid alongside of the trench. Blocks, tackle, and ropes or chain. A chain or clip to encircle the pipes. Eight hand-spikes of wood, for moving the pipes about. Two pieces of 2 or 3 in. wrought-iron tube (according to the size of the main), on which to roll the pipe previous to lowering it to its place in the trench. Two or four long iron bars, and two short ones. Two planks for long and strong leverage. Red and white lead, mixed with boiled oil, if turned and bored joints. Some cotton waste and old cards to clean the joints, if turned and bored. A supply of spun yarn and lead or lead-wool. A wooden mallet for driving small bored and turned pipes. Two or four oak blocks, strengthened with bolts or hoops, to lay against the pipe sockets when driving. A 3 or 4 in. cast-iron pipe, to swing with a rope or chain from centre of shear-legs when driving, or a wooden spring block if preferred. Wood plugs for the various sizes of pipes and branches. India-rubber cloth bags for plugging the mains. (Fig. 150.) A lead pot and two ladles. Chisels and caulking tools. Tarred rope for trying the joints and pipes. A coke fire-grate for melting the lead and for use by the night watchman. Three setts, with handles, for cutting any pipes required. Two large hammers, 7 Ibs. weight, and several smaller ones, ij, 2, and 3 Ibs". each. A 4-lb. hammer for lead-wool, arid suitable caulking tools. Screwing tackle. Some fine flax for indifferent joints. A few casks of cement. A bogie or hand-drag, and two or three hand-barrows. Portable bench, with vice attached. Covered hand-cart, under lock and key. A supply of good soil for bedding the pipes, and to prevent the contact of ashes, if such should be present in the cutting. A spirit-level and a straight-edge 10 or 14 ft. long. 258 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS A supply of planking to cover up any part of the trench temporarily. A box for the night watchman. Two red signal lamps to warn passengers of the open trench during the dark hours. Two stand-pipes for the signal lights. Apparatus for proving the mains for leak- age before filling up the trench. Look up beforehand what bends, tees, thimbles, flanges, drip-wells, and other special castings will be required in the course of the work, and have them ready when needed. rIG. 1- T i " In enlarging or replacing pipes, many ser- vices require to be coupled-up and renewed, and in that case service layers and tools should be in readiness. EXPLOSIONS IN MAIN PIPES. In the laying of large main pipes, due care and diligence should be exercised by the skilled and responsible officials 'in charge of such work. Calamitous explosions have occurred owing to neglect in these particulars. Such an explosion took place in London in 1862, and again in 1880 ; and one in Manchester in 1873, when a large cast-iron syphon well was being attached to a main. Coal gas when unmixed with air or oxygen, as is well known, is perfectly inexplosive, and is even incombustible. It is only when the gas comes in contact with the oxygen of the air, as at the burner for example, that it can be ignited ; combustion being in fact the union in the presence of heat of the hydrogen and carbon of the gas with atmospheric oxygen. Explosions of the kii\d referred to are produced by a mixture of gas and air in certain proportions. The explosive force of a com- pound of this character is greatest when gas is mixed with eight times its bulk of air. Under ordinary circumstances it is impossible for air to become mixed with the gas in the street mains. This can only occur when a main is in course of being laid, or when a fresh junction is being made with an existing main. In the case of the London explosions referred to, a new main MAIN PIPES 259 was being laid. In order to allow of this being done, the gas was either wholly or partially shut off at the junction with the live main. Probably the gas was only partially excluded ; and the limited quantity entering would, by the operation of the law of the diffusion of gases, gradually mix with the air existing in the new length of main, till the latter became charged throughout its course with a dangerously explosive compound. On the application of a light, either accidentally or from intention, the mixture was ignited, with disastrous consequences to life and property. It is not necessary that there should be the presence of actual flame to cause ignition. Dr. Frankland and other authorities have demonstrated the fact, well known to most gas engineers, that explosive mixtures of coal gas and air may be inflamed by a spark struck from stone or metal ; that ignition may be caused by a spark produced from the hammer and chisel of a workman, or even from the tramp of a hors.e upon the stone pavement. There is no absolute necessity that the gas should be excluded from such an extent of main pipes in course of being laid as to incur the risk of accident ; because the main for a short space from the point where the junction is being made can readily be closed by the ordinary india-rubber valves. When the main is of such large diameter as to preclude the possibility of a valve of this kind being used, the utmost precaution is necessary to ensure the expulsion of the air before a light is applied to test the soundness of the joints. Under any circumstances, the application of a light is objec- tionable and unnecessary, as the joints can be proved when the main is under pressure by brushing them over with a solution of soap in water. TESTING OF GAS MAINS IN THE GROUND. The reduction of the loss of gas by leakage during recent years is remarkable. It is safe to estimate that thirty years ago, the unaccounted-for gas averaged 16 per cent, of the gas produced. At the present time the average is only 7 per cent. This re- duction is largely due to the closer attention that is given to the pressures by day and night ; to the use of governors in street s 2 *6o NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS lighting ; and to the better supervision that is exercised in the laying of mains and service pipes. It may be stated as a salutary rule that, under modern pre- vailing conditions, f is a reasonable maximum initial pressure during the hours of heaviest consumption. When there is found to be a necessity for more, the trunk mains, or some of the most contracted mains branching therefrom, should be replaced by larger ones, or boosting must be resorted to. Considerable expense must be incurred in any systematic attempt to reduce leakage ; but wherever in a district the unaccounted- for gas exceeds 10 per cent, of the make, the expenditure is not only justifiable on SURFACE ROAD FIG. 151. sanitary and other grounds, but is eventually found to be a good and profitable investment. Various appliances have been devised for testing gas mains in the ground. Brothers' apparatus consists simply of two 3o-light meters, one of which registers the passage of gas in the usual way, and the other is made to act as an exhauster, either by con- tinuing the spindle of the drum through the casing and attaching a handle to it, or by means of a small wheel geared into a larger one on the periphery of the drum the former being actuated by a handle from the outside. The main having been severed, and the two ends carefully plugged, the exhauster inlet is connected to the live main, and the meter outlet to the dead section of main ; the exhauster and meter also being joined. On the exhauster being gently turned, gas is drawn from the live main and forced through the meter into the length of main under test, and thus the MAIN PIPES 261 amount of loss in a certain time, and under a given pressure, is indicated. The great cost is in cutting the pipes, reinstating them, and find- ing the exact locality of the escape. To obviate the necessity of severing the pipes, a suggestion was made at the meeting of the Manchester District Institution of Gas Engineers, in November 1879, that water valves or traps, which would also answer the purpose of drip-wells, might be permanently placed at intervals in the line of mains. These traps, having a diaphragm extending to within a regulated distance of the bottom, on being charged with water would form a hydraulic valve, shutting off the gas from any section of main as desired, and enabling a test to be made without difficulty and at reduced expense. Acting on this suggestion, Mr. J. H. Lyon has introduced an improved syphon box or hydraulic valve, for attaching to mains, and by means of a leakage indicator affixed to stand-pipes on each side of the box or valve, the quantity of gas escaping is readily ascertained. (See Fig. 151.) ELECTROLYSIS OF MAIN AND SERVICE PIPES. Since the introduction of electric lighting and traction, a new danger. to the distributing mains and other pipes of gas under- takings has arisen viz., electrolysis. For the protection of metallic substances buried in the streets, the Board of Trade has issued certain regulations ; but there is a difference of opinion as to whether these regulations are 'sufficiently stringent or not. Experiments show that quite small potential differences between iron surfaces, buried in damp soil especially, if soluble chlorides are present, may bring about considerable electrolytic corrosion in short periods of time, and that there is no absolute security in the limit of ij volts as imposed by the Board of Trade Regulations. It is essential that managers of gas undertakings should make a careful inspection of their mains and services whenever oppor- tunity occurs, and note if any corrosion is taking place. This is especially necessary at points nearest to the electrical generating stations, which are known as " danger areas." 262 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Electrolytic troubles due to electric lighting systems, whilst of importance, are less so than in the case of electric traction. They will be due to leakage from badly insulated cables, and to the fact that in a three or five wire system the middle conductor is earthed. Whenever electric lighting or traction is introduced within the district of any gas undertaking, every endeavour should be made to secure the utmost protection for the mains and service pipes from damage likely to be caused through electrolytic action or direct fusion. The electric cables and the rails should be as far distant as possible from the mains and other pipes ; and, where the former cross the latter, the mains and pipes should be protected by some insulating material. It is well understood that it is not at the point where the electric current enters a pipe that the damage is done, but where it leaves the pipe. The necessity, however, for protecting the pipe at the initial point is evident, in order to obviate or diminish the risk of currents entering. No danger of electrolysis arises through vagabond currents from the return current in electric tramways, provided the gas or water pipes are 3 ft. distant from the rails. This has been proved by investigation and from actual experiment. An effort should be made to obtain the insertion in the Order of any Electric Lighting or Tramway Company, of protective clauses including the following provisions : 1. Where the distance from the upper side of any main or service pipe belonging to the Gas Company (or local gas authority) to the lowest part of the cable or rail of the Electric Cable or Tramway Company is less than 2 ft., such main or pipe shall be lowered by the Gas Company (or local gas authority) at the expense of the Electric Lighting or Tramway Company, so as to leave a distance of not less than 2 ft. between the upper side of such main or pipe and the lowest part of such cable or rail. 2. At any point or points where the cables or rails cross a main or pipe, the Electric Lighting or Tramway Company shall, at their own expense, lay and maintain underneath each cable or rail, and immediately over such main or pipe, a bed of asphalt or other insulating material, not less than MAIN PIPES 263 2 ft. wide by 6 in. thick, and of a length extending 2 ft. beyond such main or pipe on each side thereof. 3. If it is proved that any injury or damage to any main or pipe or apparatus belonging to the Gas Company (or local gas authority), or any loss of gas, shall have resulted from electrolytic action caused by any currents generated or used for the purposes of electric lighting or traction, nothing in the Board of Trade Regulations or this Order shall relieve the Electric Lighting or Tramway Company (or local authority) from any liability to make compensa- tion for such injury, damage, or loss. It is claimed that the jute cloth covering usually employed as a protection from corrosion to steel mains is a non-conductor of electricity, and that as a consequence mains so covered are immune from the danger of electrolysis and fusion. Sufficient data, however, on this point, are not as yet available to prove the accuracy of the contention. [TABLES. 264 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS ^S^s |?1 4||- d ^jOJ CO OOl O OICO rH ret .rJOJ t- OCO O Oitx 3 O1 CM O1JO OJ OICO 3 ^ ^ ^ ^ ||| rH rH OOiH rH OJlO rH rHOl rH 111 3 ^,2 ojOl 00 COt> Ol OJ^ B H d igO * OO O O^ rd _i O CO CD *< CO OCM S q jSOl Ol Ol CO rH Ol CO 3 oSco * ^ co co co u: rrj rrJcO OS rH CO -^ COO rH 1*1 ,^00 rH "tf CO CO COO rj gg O oJrH rH OIUS rH rHOl 3 03 o5OJ CO CO ID Ol d * B w H M 1 rrjt- rH OCO CO t>O i _: co o I-H o * coc 3 dJrH rH O1O rH rHCO o 3 oSCO CO -^00 CO CO"t 1^ r^CO C- OOO rH COl> n3 ^CD O i-HCD * COO 3*5 oJrH rH rHIO O rHOI p aJOl 01 COCO 01 OJCO EH P5 EH ^ 1 rrjOl CO OOOJ O OICO i . " * 1^1 roO Ol -*CO CO OOl rH rH 1*1 c S ,^Ol CO OSOJ O OICO B. o3O rH rHCO O OOl S* o50l 01 OJCO 01 0100 B M R M 4 ^jrH O COOS O rH"tf 1 rrJO 01 001 CO OCO Hn V oJrH -H rHCO rH rHOl 3 n5OJ O COt- Ol CM * 01 1*1 rflOS O rHCO t- OSO * ~+ S-o'S ra rH COrH rH rH 1C | o5O rH rHCO O OOl Gas S o5 nJOl Ol O1CO rH OICO H EH w 1 frjO CO * CO rH OOl *j IQCO O rH OS CO COO rH rH ro I P jJrH rH rH CO O rHOl 3 on 1 Ol CM COCO Ol OICO Turned and Bored. reCO rH 001 CO COO ojO O -H CO O O rH Turned and Bored. rflO Ol OO t- OOJ rH rH rH on rH Ol Ol O rH i 1 CO .15 fl 'T ' T ' ' P ^ * * " ' S ' ffl J * -s Diameter in Inohc Description of Join rd "S ,d -^5 SS-SrsS* . & 8 ^|s^^ |-a 1 HI'S -3s ^iKlJill SoOrt <;8 fl <:S(I>c8 S ar^J a a p.ja ftS, l22lllpl Diameter in Inche Description of Join rrj -^ . 0) ^ 'S OU^ -^ 08 o ^> olo^ ^^ a a a a a a o d a a a a d z. 1 1 rH M I-H M t 1 1 MAIN PIPES 265 t- 00 CO t> tCJS CO 00O O OSO 10 to o ^ to co 4 CO CO 1 * * l>rH t- t-OS o I .3 eo ooo oco t- t-O O t>00 ,^0 CO ,O O i 1 i 1 OSCO Ot- OCO OS Oi-i t> rHOO COCO OJ -*O C t>00 O rHCO CO tOr-j CO C- 1 COO OI> O O t> CO OSCO os os i-i ^fH C- ooC- C- OCO C-CO rHC- CO C-OD O CO ^*1 IO I> rH O CO rH IO tO t- iH CO OCO cn -*o rH OS OSO cs too t> osco -*05 CO C00 cl aJCO C- too cco CO 00 Ol CO COCO 4 CQ C~ O 3D O CQ OS to o o to toco .JU3 rHIO CO U30 afCO CO -4100 O COO 01 tOCO t> OSCO ^CO 00 rHCO O COOS mco co coco co rs * a a a a a o a t>0 OSCO 111 ,^CO OS oaco co OCO O 5 6 5 5 7 2 7 4 7 3 o lo u 6 17 6 4 8 4 9 10 4 9 O 5 7 5 9 6 8 7 5 7 7 7 7 700 4 10 4 11 4 10 5 8 5 10 5 9 7 7 7 9 7 8 726 4 11 5 5 5 9 5 11 5 10 7 8 7 11 7 10 750 5 5 1 5 1 5 11 6 5 11 7 10 8 8 776 5 1 5 2 5 2 6 6 1 6 1 6- 8281 7 10 5 2 5 3 5 3 6 1 6 3 6 2 a i 8 4 8 3 7 12 6 5 3 5 5 5 4 6 2 6 4 6 3 8 3 8 5 8 4 7 15 5 4 5 6 5 5 6 3 6 5 6 4 8 4 8 7 8 6 7 17 6 5 6 5 7 5 6 6 5 6 6 6 6 8 6 8 9 8 8 800 5 6 5 8 5 7 6 6 6 8 6 7 8 8 8 10 8 9 826 5 7 5 9 5 8 6 7 6 9 6 8 8 9 9 8 11 850 5 8 6 10 5 9 6 8 6 10 6 y 8 11 9 2 9 1 876 5 9 5 11 5 10 6 10 6 11 6 10 9 1 9 3 9 2 8 10 5 10 6 5 11 6 11 7 7 9 2 9 5 9 4 8 12 6 5 11 6 1 6 7 7 2 7 1 9 4 9 7 9 6 8 15 6 6 2 6 1 7 1 7 3 7 2 9 5 9 8 9 7 8 17 6 6 1 6 3 6 2 7 3 7 4 7 3 9 7 9 10 9 9 900 6 2 ' 6 4 6 3 7 4 7 6 7 5 9 9 10 9 10 926 63;66 6 4 7 6 7 7 7 6 9 10 10 1 10 950 6 4 6 6 6 5 7 6 7 8 7 7 10 10 3 10 2 976 6 5 6 7 6 6 7 7 7 9 7 8 10 2 10 5 10 4 9 10 6 6 6 8 6 7 7 9 7 10 7 10 10 3 10 6 10 5 9 12 6 6 7 6 9 6 8 7 10 8 7 11 10 5 10 8 !10 7 9 15 6 8 6 10 6 9 7 11 8 1 8 10 6 10 10 10 8 9 17 6 6 9 6 11 6 11 8 8 2 8 1 10 8 10 11 10 10 10 6 11 7 1 7 8 2 8 4 8 3 10 10 a i 11 268 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS TABLE (riving Weight and Cost per Yard of Cast-Iron Main Gas Pipes 8, 9, and 10 inches diameter, at Rates from 4 to 10 per Ton. (Calculated to the nearest Penny.) Diameter in Inches. 8. 9, 10. Class of Joint. Open. T. &B Flnge Open T.&B Flnge Open T. &B Flnge. Weight per Yard in Ibs. 137 140 139 153 167 155 192 196 194 Coat per yard at s. d. s. d. a. d s. d. B. d. 8. d. 8. d. s. d. S. d. 4 per ton. 4 11 6 6 5 6 6 7 6 6 6 10 7 6 11 2 6 5 1 6 2 5 1 5 8 6 9 5 9 7 1 7 3 7 2 60,, 6 2 6 4 6 3 5 10 6 6 11 7 8 7 5 7 4 76 6 4 6 6 5 6 6 6 2 6 1 7 6 7 8 7 7 10 6 6 5 8 5 7 6 2 6 4 6 3 7 9 7 11 7 10 12 6 6 8 6 9 6 9 6 4 6 6 6 6 7 11 8 1 8 4 16 5 10 5 11 5 11 6 6 6 8 6 7 8 2 8 4 8 3 4 17 6 6 6 1 6 1 6 8 6 10 6 9 8 4 8 6 8 5 600 6 1 6 3 6 2 6 10 7 6 13 8 7 8 9 8 8 626 5fi 6 3 6*- 6 6 6rj 6 4 7 7 2 7 1 8 9 9/1 9 9n 8 11 9-1 O \J ,, 576 6 7 ( 6 -9 6 8 7 4 7 6 7 6 u 9 8 9 6 1 9 4 6 10 6 8 6 11 6 10 7 6 7 9 7 7 9 6 9 8 9 6 6 12 6 6 11 7 7 7 8 7 11 7 9 9 8 9 10 9 9 6 16 7 7 2 7 2 7 10 8 1 7 11 9 10 10 1 10 6 17 6 7 2 7 4 7 8 8 8 8 8 2 10 1 10 3 10 2 600 7 4 7 6 7 6 8 2 8 6 8 4 10 3 10 6 10 6 626 7 6 7 8 7 7 8 4 8 7 8 6 10 6 10 9 10 7 660 7 8 7 10 7 9 8 6 8 9 8 8 10 9 1011 10 10 676 7 10 8 7 11 8 8 8 11 8 10 10 11 11 2 11 1 6 10 7 11 8 2 8 1 8 10 9 1 9 11 2 11 6 11 3 6 12 6 8 1 8 3 8 3 9 1 9 3 9 2 11 4 11 7 11 6 6 15 8 3 8 5 8 6 9 3 9 6 9 4 11 7 11 10 11 8 6 17 6 8 6 8 7 8 6 9 5 9 8 9 6 11 9 12 11 11 700 8 7 8 9 8 8 9 7 9 10 9 8 12 12 3 12 1 726 8 9 8 11 8 10 9 9 10 9 10 12 8 12 6 12 4 760 8 10 9 1 9 9 11 10 2 10 12 5 12 8 12 6 776 9 9 3 9 2 10 1 10 4 10 2 12 8 12 11 12 9 7 10 9 2 9 6 9 4 10 3 10 6 10 6 12 10 13 2 13 7 12 6 9 4 9 6 9 6 10 6 10 8 10 7 13 1 13 4 13 2 7 15 9 6 9 8 9 7 10 7 10 10 10 9 13 4 13 7 13 6 7 17 6 9 8 9 10 9 9 9 11 10 11 13 6 13 9 13 7 800 9 9 10 9 11 11 11 3 11 1 13 9 14 13 10 826 9 11 2 1 1 1 11 6 11 8 13 11 14 3 14 860 1 4 3 1 3 11 7 11 5 14 2 14 6 4 3 876 3 6 5 1 6 11 9 11 7 14 4 14 8 14 6 8 10 5 8 7 1 7 11 11 11 9 14 7 14 11 4 8 8 12 6 7 9 8 1 9 12 1 11 11 14 9 5 1 4 11 8 16 8 11 10 1 11 12 8 12 1 6 6 4 5 2 8 17 6 10 1 1 1 2 1 12 5 2 3 6 2 6 6 5 4 900 1 1 3 1 2 2 3 2 7 12 6 5 6 6 9 6 7 926 1 2 1 5 1 4 2 6 2 9 2 8 6 7 6 5 9 960 1 4 1 7 1 6 2 8 3 2 10 5 10 6 2 6 976 1 6 1 9 1 8 2 10 3 2 3 6 6 6 6 2 9 10 1 7 1 11 1 9 d 3 4 3 2 6 3 6 8 6 6 9 12 6 1 9 2 1 11 3 2 3 6 3 4 6 6 6 10 6 8 9 16 I 11 2 2 2 1 3 4 3 8 3 6 6 8 7 1 6 10 9 17 6 2 1 2 4 2 3 3 6 3 10 3 8 6 10 7 8 7 1 10 2 3 2 6 2 5 6 8 4 8 10 7 2 7 6 7 8 MAIN PIPES 269 TABLE Giving Weight and Cost per yard of Cast-Iron Main Gas Pipes, 11, 12, and 13 inches diameter, at Rates from 4 to 10 per Ton. (Calculated to the nearest Penny.} Diameter in Inches. 11. 12. 18. Ciass of Joint. Open. T.&B. Flnge. Open. T.&B. Flnge. Open. T.&B. Flnge, Weight per yard in Ihs. 210 215 212 249 253 251 269 273 271 Cost per yard at 8. d. 1. d. 8. d. 8. d. s. d. 8. d. s. d. 8. d. s. d. 4. per ton 7 6 7 8 7 7 8 11 9 9 9 7 9 9 9 8 426 7 9 7 11 7 10 9 2 9 4 9 3 9 11 10 1 10 450 8 8 2 8 9 6 9 7 9 6 10 3 10 4 10 3 476 8 2 8 5 8 3 9 9 9 11 9 10 10 6 10 8 10 7 4 10 8 5 8 8 8 6 10 10 2 10 1 10 10 11 10 11 412 6 8 8 8 11 8 9 10 3 10 5 10 4 11 1 11 3 11 2 4 15 8 11 9 1 9 10 6 10 9 10 8 11 6 11 7 11 6 4 17 6 9 2 9 4 9 3 10 10 11 10 11 11 9 11 11 11 10 500 9 4 9 7 9 5 11 1 11 4 11 3 12 12 2 12 1 526 9 7 9 10 9 8 11 4 11 7 11 6 12 4 12 6 12 5 650 9 10 10 1 9 11 11 7 11 10 11 9 12 7 12 10 12 8 676 10 1 10 4 10 2 11 11 12 2 12 12 11 13 1 13 5 10 10 4 10 7 10 5 12 2 12 5 12 4 13 3 13 5 13 4 5 12 6 10 7 10 10 10 8 12 5 12 8 12 7 13 6 13 9 13 7 5 15 10 10 11 1 10 10 12 9 13 12 11 13 10 14 13 11 5 17 6 11 11 3 11 1 13 1 13 3 13 2 14 1 14 4 14 3 600 Jl 3 11 6 11 4 13 4 13 7 13 5 14 5 14 8 14 6 626 11 6 11 9 11 7 13 7 13 10 13 9 14 9 14 11 14 10 650 11 9 12 11 10 13 11 14 1 14 15 15 3 15 2 676 11 11 12 3 12 1 14 2 14 5 14 3 15 4 15 6 15 5 6 10 12 3 12 6 12 4 14 5 14 8 14 7 15 7 15 10 15 9 6 12 6 12 5 12 8 12 6 14 9 15 14 10 15 11 16 2 16 6 15 12 8 13 12 9 15 15 3 15 2 16 3 16 5 16 4 6 17 6 12 11 13 2 13 15 3 15 6 15 5 16 6 16 9 16 8 700 13 2 13 5 13 8 15 7 15 10 15 8 16 10 17 1 16 11 726 13 5 13 8 13 6 15 10 16 1 16 17 1 17 4 17 3 750 13 7 13 10 13 9 16 1 16 5 16 3 17 5 17 8 17 7 776 13 10 14 2 14 16 5 16 8 16 6 17 9 18 17 10 7 10 14 2 14 5 14 2 16 8 16 11 16 10 18 18 3 18 2 7 12 6 14 4 14 8 14 5 16 11 17 3 17 1 18 4 18 7 18 5 7 15 14 6 14 11 14 8 17 3 17 6 17 4 18 7 18 11 18 9 7 17 6 14 9 15 1 14 11 17 6 17 9 17 8 13 11 19 2 19 1 800 15 15 4 15 2 17 10 18 1 17 11 19 3 19 6 19 4 826 15 3 15 7 15 4 18 1 18 4 18 2 19 6 19 10 19 8 850 15 6 15 10 15 7 18 4 18 7 18 5 19 10 20 1 20 876 15 8 16 1 15 10 18 8 18 11 18 9 20 1 20 5 20 3 8 10 15 11 16 4 16 1 18 11 19 2 19 20 5 20 9 20 7 8 12 6 16 2 16 7 16 4 19 2 19 6 19 4 20 9 21 20 10 8 15 16 5 16 10 16 7 19 6 19 9 19 7 21 21 4 21 2 8 17 6 16 8 17 16 9 19 9 20 1 19 11 21 4 21 8 21 6 900 16 10 17 3 17 20 20 4 20 2 21 7 21 11 21 9 926 17 1 17 6 17 3 20 4 20 7 20 5 21 11 22 3 22 1 960 17 4 17 9 17 6 20 7 20 11 20 9 22 3 22 7 22 5 976 17 7 18 17 9 20 10 21 2 21 22 6 22 10 22 8 9 10 17 ]0 18 3 18 21 2 21 6 21 4 22 10 23 2 23 9 12 6 18 1 18 6 18 3 21 5 21 9 21 7 23 1 23 6 23 4 915 18 3 18 9 18 6 21 8 22 21 10 23 5 23 9 23 7 9 17 6 18 6 19 18 8 22 22 4 22 2 23 9 24 1 23 11 1U 18 9 19 2 18 11 22 3 22 7 22 5 24 24 24 3 2 7 o NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS TABLE Giving Weight and Cost per Yard of Cast-Iron Main Gas Pipes, 14, 15, and 16 indies diameter, at Rates from 4 to 10 per Ton. (Calculated to the nearest Penny.) Diameter in inches. 14. 15. 16. Class of Joint. Open. T.&B Flnge Open T.&B Flnge Open. T.&B Flnge. Weight per yard in Ibs. 289 298 291 309 814 311 863 868 306 Cost per yard at s. d. 8. d. s. d s. d 8. d s. d 8. d s. d S. d. i'4 per ton. 10 4 10 6 10 5 11 11 3 11 1 13 13 2 13 1 426 10 8 10 9 10 9 11 6 11 7 11 5 13 4 13 7 13 6 450 11 11 1 11 1 11 9 11 11 11 10 13 9 14 13 11 476 11 3 11 5 11 4 12 1 12 3 12 2 14 2 14 5 14 4 4 10 11 7 11 9 11 8 12 5 10 7 12 6 14 7 14 9 14 8 4 12 6 11 11 12 1 12 12 9 16 12 10 15 15 2 15 1 4 15 12 3 12 5 12 4 13 1 13 4 13. 2 15 5 15 7 15 6 4 17 6 12 7 12 9 12 8 13 5 13 8 13 6 15 10 16 15 11 500 12 11 13 1 13 13 10 14 13 11 16 2 16 5 16 4 526 13 3 13 5 13 4 14 2 14 4 14 3 16 7 16 10 16 9 650 13 7 13 9 13 8 14 6 14 9 14 7 17 17 3 17 2 576 13 10 14 1 14 14 10 15 1 14 11 17 6 17 8 17 7 5 10 14 2 14 5 14 3 15 2 15 6 15 3 17 10 18 1 18 6 12 6 14 6 14 9 14 7 15 6 15 9 15 7 18 3 18 6 18 5 5 15 14 10 15 14 11 15 10 16 1 15 11 18 8 18 11 18 9 5 17 6 15 2 15 4 15 3 16 3 16 6 16 4 19 19 4 19 2 600 15 6 15 8 15 7 16 7 16 10 16 8 19 6 19 8 19 7 626 15 10 16 15 11 16 11 17 2 17 19 10 20 2 20 650 16 1 16 4 16 3 17 3 17 6 17 4 20 3 20 6 20 5 676 16 5 16 8 16 7 17 7 17 10 17 8 20 8 20 11 20 10 6 10 16 9 17 16 11 17 11 18 3 18 21 1 21 4 21 3 6 12 6 17 1 17 4 17 3 18 3 18 7 18 5 21 21 9 21 8 6 15 17 5 17 8 17 6 18 7 18 11 18 9 21 10 22 2 22 1 6 17 6 17 9 18 17 10 19 19 3 19 1 22 3 22 7 22 6 700 18 1 18 4 18 2 19 4 19 7 19 5 22 8 23 22 10 726 18 5 18 8 18 6 19 8 20 19 9 23 1 23 5 23 3 750 18 8 18 11 18 10 20 20 4 20 1 23 6 23 10 23 8 776 19 19 4 19 2 20 4 20 8 20 6 23 11 24 3 24 1 7 10 19 4 19 7 19 6 20 8 21 20 10 24 4 24 8 24 6 7 12 6 19 8 19 11 19 10 21 21 5 21 2 24 9 25 1 24 11 7 15 20 20 3 20 2 21 4 21 9 21 6 25 1 25 5 25 4 7 17 6 20 4 20 7 20 6 21 9 22 1 21 10 25 6 25 11 25 9 800 20 8 20 11 20 9 22 1 22 5 22 2 25 11 26 3 26 2 826 21 21 3 21 1 22 5 22 9 22 7 26 4 26 8 26 7 850 21 3 21 7 21 5 22 9 23 2 22 11 26 9 27 3 26 11 876 21 7 21 11 21 9 23 1 23 6 23 3 27 2 27 6 27 4 8 10 21 11 22 3 22 1 23 5 23 10 23 7 27 6 27 11 27 9 8 12 6 22 3 22 7 22 5 23 10 24 2 23 11 27 11 28 4 28 2 8 15 22 7 22 11 22 9 24 2 24 6 24 3 28 4 28 9 28 7 8 17 6 22 11 23 3 23 1 24 6 24 10 24 8 28 9 29 2 29 900 23 3 23 6 23 4 24 10 25 3 25 29 2 29 7 29 5 926 23 7 23 10 23 9 25 2 25 7 25 4 29 7 30 29 10 950 23 10 24 2 24 25 6 25 11 25 8 30 30 5 30 3 976 24 2 24 6 24 4 25 10 26 3 26 30 5 30 10 30 8 9 10 24 6 24 10 24 8 26 2 26 7 26 4 30 9 31 2 31 9 12 6 24 10 25 2 25 26 7 27 26 9 31 2 31 8 31 5 9 15 25 2 25 6 25 4 26 11 27 4 27 1 31 7 32 31 10 9 17 6 25 6 25 10 25 8 27 3 27 8 27 5 32 32 5 32 3 10 25 10 26 2 26 27 7 28 27 9 32 5 ,32 10 32 8 MAIN PIPES 27! TABLE Giving Weight and Cost per Yard of Cast-Iron Main Gas Pipes, 17, 18, and 19 indies diameter, at Rates from 4 to 10 per Ton. (Calculated to the nearest Pennif.) Diameter in Inches. 17. 18. 19. Class of Joint. Open. J?. AB. Flnge Open. T.&B. Flnge. Open. T.&B. Flnge. Weight per yard in Ibs. Ml 890 887 106 412 409 468 475 472 Cost per yard at s. d. 8. d. s. d. s. d. 8. d. S. d. s. d. 8. d. s. d. 400 per ton. 13 8 13 11 13 10 14 6 14 8 14 7 16 8 16 11 16 10 426 14 2 14 4 14 8 14 11 16 2 15 1 17 3 17 6 17 5 450 14 7 14 9 14 8 15 5 15 7 15 6 17 9 18 17 11 476 15 15 3 15 1 15 10 16 1 16 18 3 18 7 18 5 4 10 15 5 15 8 15 6 16 4 16 7 16 5 18 10 19 1 18 11 4 12 6 15 10 16 1 15 11 16 9 17 16 11 19 4 19 7 19 6 4 15 16 3 16 6 16 5 17 2 17 6 17 4 19 10 20 2 20 4 17 6 16 9 17 16 9 17 8 17 11 17 10 20 4 20 8 20 7 500 17 2 17 5 17 3 18 1 18 5 18 3 20 11 21 2 21 1 526 17 7 17 10 17 9 18 7 18 10 18 9 21 5 21 9 21 7 550 18 18 3 18 2 19 19 4 19 2 21 11 22 3 22 1 576 18 6 18 9 18 7 J9 6 19 9 19 8 22 6 22 10 22 8 6 10 18 10 19 2 19 19 11 20 8 20 1 23 23 4 23 2 5 12 6 19 3 19 7 19 5 20 5 20 8 20 6 23 6 23 10 23 8 5 15 19 -8 20 19 10 20 10 21 2 21 24 24 6 24 3 5 17 6 20 2 20 5 20 4 21 4 21 7 21 6 24 7 24 11 24 9 600 20 7 20 11 20 9 21 9 22 1 21 11 25 1 25 5 25 3 626 21 21 4 21 2 22 2 22 6 22 4 25 7 26 25 10 650 21 5 21 9 21 7 22 8 23 22 10 26 1 26 6 26 4 676 21 10 22 2 22 23 1 23 5 23 3 26 8 27 26 10 6 10 22 3 22 7 22 5 23 7 23 11 23 9 27 2 27 7 27 5 6 12 6 22 9 23 1 22 11 24 24 4 24 2 27 8 28 1 27 11 6 15 23 2 23 6 23 4 24 5 24 10 24 8 28 2 28 7 28 5 6 17 6 23 7 23 11 23 9 24 11 25 3 25 1 28 7 29 2 29 700 24 24 4 24 2 25 4 25 9 25 7 29 3 29 8 29 6 726 24 5 24 10 24 7 25 10 26 3 26 29 9 30 3 30 750 24 10 25 3 25 26 3 26 8 26 6 30 3 30 9 30 7 776 25 3 25 8 25 6 26 9 27 2 26 11 30 10 31 3 31 1 7 10 25 8 26 1 25 11 27 2 27 7 27 5 31 4 31 10 31 8 7 12 6 26 2 26 7 26 4 27 8 28 1 27 10 31 10 32 4 32 2 7 15 26 7 27 26 9 28 1 28 6 28 3 32 4 32 10 32 8 7 17 6 27 27 5 27 2 28 7 29 28 9 32 11 33 5 33 2 800 27 5 27 10 27 8 29 29 5 29 2 33 5 33 11 33 8 826 27 10 28 4 28 1 29 5 29 11 29 8 33 11 34 6 34 3 850 28 3 28 9 28 6 29 11 30 4 30 1 34 6 35 34 9 876 28 8 29 2 28 11 30 4 80 10 30 7 35 35 6 35 4 8 10 29 12 29 7 29 4 30 10 31 3 31 35 6 36 35 10 8 12 6 29 7 30 29 10 31 3 31 8 31 6 36 1 36 7 36 4 8 15 30 30 5 30 3 31 8 32 2 31 11 36 7 87 1 36 10 8 17 6 30 5 30 11 30 8 32 2 32 8 32 5 37 1 87 8 37 5 900 30 10 81 4 31 1 32 7 33 1 32 10 37 7 38 2 37 11 t v 2 6 31 3 31 9 31 6 33 1 33 7 33 4 38 2 38 8 38 5 950 " 31 8 32 2 81 11 33 6 34 33 9 33 8 89 3 39 976 32 1 32 8 32 5 34 34 6 84 3 89 2 89 9 39 6 9 10 32 7 33 1 32 10 34 6 34 11 34 8 39 8 40 3 40 9 12 6 33 33 6 33 8 34 11 85 6 35 2 40 3 40 10 40 7 9 15 33 6 33 11 33 8 35 4 35 10 35 7 40 9 41 4 41 1 9 17 6 33 10 34 5 34 ] 35 10 36 4 36 1 41 3 41 11 41 7 10 34 8 34 10 84 7 36 3 36 9 36 6 41 9 42 5 42 2 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS TABLE Giving Weight and Cost per Yard of Cast-Iron Main Gas Pipes, 20, 21, and 22 inches diameter, at Hates from 4 to 10 per Ton. (Calculated to the nearest Penny.} Diameter in Inches. 20. 21. 22. Glaus of Joint. Open. T. &B. Flnge. Open. T. & E.j Flnge. Open. r.&B. Flnge. Weight per yard In Ibs. 492 500 . 496 616 524 520 589 595 590 Cost per yard at s. d. s. d. 8. d. s. d. s. d. s. d. S. d. s. d. 8. d. 4 per ton. 17 7 17 10 17 8 18 5 18 8 18 7 20 11 21 3 21 1 426 18 1 18 5 IS 3 19 19 4 19 2 21 7 21 11 21 9 450 18 8 19 18 10 19 7 19 11 19 9 22 8 22 7 22 6 476 19 3 19 6 19 5 20 2 20 6 20 4 22 11 23 3 23 1 4 10 19 9 SO 19 11 20 9 21 1 20 11 23 6 23 11 23 8 4 12 6 " 20 4 20 8 20 6 21 4 21 8 21 6 24 2 24 7 24 4 4 15 20 10 21 2 21 21 10 22 8 22 1 24 10 25 3 25 4 17 6 21 6 21 9 21 7 22 6 22 10 22 8 25 6 25 11 25 8 600 21 11 22 4 22 2 23 23 6 23 2 26 2 26 7 26 4 526 22 6 22 11 22 8 23 7 24 23 9 26 10 27 3 27 550 23 1 23 5 23 3 24 2 24 7 24 4 27 5 27 11 27 8 576 23 7 24 28 10 24 9 25 2 25 28 1 23 7 28 4 5 10 24 2 24 7 24 4 25 4 25 9 25 6 28 9 29 3 29 5 12 6 24 9 25 1 24 11 25 11 26 4 26 1 29 6 29 11 29 8 6 15 25 3 25 8 25 5 26 6 26 11 26 8 30 1 30 G 30 3 5 17 6 , 25 10 26 3 26 27 1 27 6 27 3 30 9 31 3 30 11 600 26 4 26 9 26 7 27 8 28 1 27 10 31 6 31 10 31 7 626 26 11 27 4 27 2 28 3 28 8 28 5 32 32 6 32 8 650 27 5 27 11 27 8 28 29 3 29 32 8 33 2 32 11 676 28 28 6 28 3 23 4 29 10 29 7 33 4 33 10 33 7 6 10 28 7 29 28 9 29 11 30 6 30 2 34 34 6 34 3 6 12 6 29 1 29 7 29 4 30 6 31 30 9 34 8 35 2 34 11 6 16 29 8 30 1 29 11 31 1 31 7 31 4 35 4 35 10 35 7 6 17 6 30 2 30 8 30 5 31 8 32 2 31 11 36 36 6 36 3 700 30 9 31 3 31 32 3 32 9 32 6 36 7 37 2 36 10 726 31 4 31 10 31 7 32 10 33 4 33 1 37 8 37 10 37 6 750 31 10 32 4 32 1 33 5 33 11 33 8 87 11 88 6 38 2 776 32 6 32 11 32 8 34 34 6 34 3 38 7 39 2 38 10 7 10 32 11 33 6 33 2 34 7 35 1 34 10 39 3 39 10 39 6 7 12 6 33 6 34 33 9 35 2 35 8 35 5 39 11 40 6 40 2 7 15 34 34 7 34 4 35 8 36 3 36 40 6 41 2 40 10 7 17 6 34 7 35 2 34 11 36 3 36 10 36 7 41 2 41 10 41 6 800 35 2 35 8 35 5 36 10 37 5 37 2 41 10 42 6 42 2 826 ^ 35 8 36 3 36 37 6 38 37 9 42 6 43 2 42 10 850 36 3 36 10 36 6 38 38 7 38 4 43 2 43 10 43 5 876 36 9 37 5 37 1 38 7 39 2 38 11 43 10 44 6 44 1 8 10 37 4 37 11 37 8 39 2 39 9 39 5 44 6 45 2 44 9 8 12 6 37 11 38 6 28 2 39 9 40 4 40 45 2 45 10 45 5 8 15 38 6 39 1 38 9 40 4 40 11 40 7 45 9 46 6 46 1 8 17 6 39 39 7 39 4 40 11 41 6 41 2 46 5 47 2 46 9 900 39 6 40 2 39 10 41 6 42 1 41 9 47 1 47 10 47 5 926 40 1 40 9 40 5 42 42 8 42 4 47 9 48 6 48 1 950 40 7 41 3 40 11 42 7 43 3 42 11 48 5 49 2 48 9 976 41 2 41 10 41 6 43 2 43 10 43 6 49 1 49 10 49 5 9 10 41 9 42 5 42 1 43 9 44 5 44 1 49 8 50 5 50 9 12 6 42 3 43 42 8 44 4 45 44 8 50 4 51 1 50 8 9 15 42 10 43 6 43 2 44 11 45 7 45 3 51 51 9 51 4 9 17 6 43 5 44 1 43 9 45 6 46 2 45 10 51 8 52 5 52 10 43 11 44 8 44 3 46 1 46 9 46 5 52 4 53 1 52 8 MAIN PIPES 273 TABLE Giving Weight and Cost per Yard of Cast- Iron Main Gas Pipes y 23, 24, and 30 inches diameter, at Rates from 4 to 10 per Ton. (Calculated to the nearest Penny.) Diameter in Inches. 23. 24. | 80. Class of Joint. Open T.& Flng Ope T. & B.| Flnge.1 Open T.A Flnge. Weight per yard in Ibs. 611 621 616 688 699 693 1 980 995 987 Cost per yard at S. ( 8. C 8. ( 8. ( 8. ( 8. d 1 8. d 8. ( 8. d. '400 per ton. 21 1 22 22 24 24 1 24 9135 35 35 3 426 22 22 1 22 25 25 25 6136 36 36 4 450 23 23 23 26 26 26 3|37 37 37 5 476 23 10 24 24 26 1 27 27 1138 38 10 38 7 4 10 24 6 24 1 24 27 28 27 10139 40 39 8 4 12 6 25 3 25 8 25 28 28 10 28 7|40 6 41 1 40 9 4 15 25 11 26 4 26 29 29 8 29 5|41 7 42 2 41 10 4 17 6 26 7 27 26 10 29 1 30 5 30 2142 8 43 4 43 500 27 3 27 9 27 6 30 8 31 2 30 111 43 9 44 5 44 1 526 ,, 28 28 5 28 2 31 6 32 31 9144 10 45 6 45 2 550 28 8 29 1 28 10 32 3 32 9 32 6|45 11 46 8 46 3 576 29 4 29 10 29 7 33 33 7 33 3147 47 9 47 4 5 10 30 30 6 30 3 33 9 34 4 34 0|48 1 48 10 48 5 5 12 6 30 8 31 2 30 11 34 7 35 1 34 10149 3 50 49 7 5 15 31 4 31 10 31 7 35 4 S5 11 35 7150 4 51 1 50 8 6 17 6 32 1 32 7 32 4 36 1 36 8 36 4|51 5 52 2 51 9 600 2 9 33 3 33 6 10 37 5 37 1|52 6 53 4 52 10 626 3 5 34 33 8 7 8 38 3 37 111 53 7 54 5 54 650 34 1 34 8 34 4 8 5 39 38 8154 8 55 6 65 1 676 4 9 35 4 35 1 9 2 9 9 39 5 155 9 6 8 56 2 6 10 5 5 36 35 9 9 11 40 7 40 2 56 10 7 9 57 3 6 12 6 6 2 6 9 36 5 40 8 1 4 41 0|58 58 10 58 5 6 15 6 10 7 5 7 1 1 5 42 1 1 9159 1 9 11 9 6 6 17 6 7 6 38 1 7 10 2 3 42 11 2 6160 2 1 60 7 700 8 2 38 10 38 6 3 3 8 43 4161 3 2 2 1 8 726 8 10 9 6 9 2 3 9 44 6 44 1 62 4 63 3 2 9 760 9 6 2 9 10 44 6 5 3 44 10 63 5 64 5 3 11 776 40 3 40 11 40 7 5 4 6 45 7|64 6 5 6 65 7 10 11 1 7 1 3 6 1 46 10 6 5165 7 66 7 6 1 7 12 6 71 C f\ 1 7 O Q 2 3 on 1 11 46 10 7 7 7 2|66 9 7 8 8in 7 2 fift q lo U ,| 7 17 6 - o 2 11 Z 11 3 8 3 4 48 5 9 2 48 9|68 11 1U 9 11 3 O 9 5 800 8O U 3 8 4 4 4 9 2 91 -i 9 11 Of\ 9 6170 1 6 55 D H 850 5 45 9 45 4 11 8 y 1 6 1 0172 2 3 3 2 8 876 5 8 6 5 6 1 1 5 2 3 1 101 73 3 4 4 3 10 8 10 46 4 7 1 6 9 2 2 3 2 7174 4 5 6 4 11 8 12 6 7 7 10 7 5 3 3 10 53 4175 6 6 8 6 8 15 n 7 9 48 6 8 2 3 9 4 7 54 2l 76 7 7 9 7 1 8 17 6 8 5 9 3 8 10 4 6 5 5 411177 8 8 10 8 3 900 9 1 9 11 9 6 5 3 6 2 5 8 78 9 9 11 9 4 926 9 9 7 2 6 1 6 11 6 6 79 10 1 1 BO 5 950 5 1 3 10 6 10 7 9 7 3|80 11 2 2 1 6 976 1 2 2 1 7 7 7 8 6 8 0182 3 3 32 7 9 10 1 10 2 8 2 3 58 4 9 3 8 9183 1 4 5 3 8 9 12 6 2 6 3 4 2 11 9 2 1 9 7|84 2 5 6 4 10 9 15 3 2 4 1 3 7 9 11 60 10 50 4185 4 36 7 5 11 9 17 6 3 10 ' 54 9 4 4 8 1 8 1 l|86 5 7 9 37 10 4 7 55 5 5 1 5 2 5 1 10|87 6 38 10 38 1 274 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS TABLE (living Weight and Cost per Yard of Cast-Iron Main Gas Pipes 36, 42, and 48 inches diameter, at Rates from 4 to 10 per Ton. (Calculated to the nearest Penny.) Diameter in Inches. 86. 42. 48. Class of Joint. Open T. &B Flng Open T.&B Flng Open T.&B Flnge. Weight per yard in Ibs. 1820 1841 13SO 1621 1646 1638 1946 1976 1961 Cost per yard at 8. d s. d s. d s. d s. d S. C s. d 8. d s. d. 4 per ton. 47 47 1 47 57 1 58 58 69 70 70 426 48 49 49 59 60 60 71 72 72 3 450 50 50 1 50 61 62 61 1 73 1 75 74 5 476 51 52 51 1 63 64 63 75 1 77 76 7 4 10 53 53 1 53 65 66 65 78 79 78 9 4 12 6 54 55 54 1 66 1 68 67 80 81 81 4 15 56 66 1 56 68 69 1 69 82 83 1 83 2 4 17 6 1 57 58 67 1 70 71 71 84 86 85 4 500 58 1 59 1 59 72 73 72 1 86 1 88 87 6 626 60 61 4 60 1 74 75 74 89 90 89 9 650 61 1 62 1C 62 76 77 76 91 92 91 11 676 63 4 64 4 63 1 77 10 79 78 93 94 1 94 1 6 10 64 10 65 10 65 4 79- 7 80 10 80 95 97 96 8 6 12 6 66 4 67 4 66 10 81 5 82 8 82 97 99 3 98 6 6 15 67 9 68 10 68 3 83 3 84 6 83 10 99 1 101 6 100 8 6 17 6 69 8 70 4 69 9 85 86 4 85 8 102 103 8 102 10 600 70 8 71 10 71 3 86 10 88 2 87 6 104 3 105 10 105 1 626 72 2 73 4 72 9 88 8 90 89 3 106 5 108 107 3 650 73 8 74 10 74 2 90 6 91 10 91 1 108 7 110 3 09 5 676 75 2 76 4 76 8 92 8 93 8 92 11 110 8 112 6 11 7 6 10 76 7 77 10 77 2 94 1 95 6 94 9 112 11 14 8 13 10 6 12 6 78 1 79 8 78 8 95 11 97 4 96 8 115 1 16 11 16 6 15 79 7 80 10 80 2 97 8 99 2 98 6 117 3 19 1 18 2 6 17 6 81 82 4 81 8 99 6 01 00 3 19 6 21 4 20 6 700 82 6 83 10 83 1 01 4 02 10 02 1 21 7 23 6 22 4 726 84 85 4 84 7 03 1 04 9 03 11 23 10 25 8 24 7 750 85 6 86 10 86 1 04 11 06 6 05 8 26 27 11 26 10 776 86 11 88 4 87 7 06 9 08 5 07 6 28 2 30 1 29 1 7 10 88 5 89 9 89 1 08 6 10 3 09 4 30 4 32 4 31 2 7 12 6 89 10 91 4 90 6 10 4 12 1 11 2 82 6 34 6 38 4 7 15 91 4 92 9 92 12 2 13 11 13 34 8 36 9 35 3 7 17 6 92 10 94 8 93 6 14 15 9 14 10 36 10 38 11 37 11 800 94 3 95 9 95 15 9 17 7 16 8 39 41 2 40 1 8 2 6 95 9 97 8 96 6 17 7 19 5 18 6 41 2 43 4 42 8 850 97 8 98 9 97 11 19 5 21 3 20 3 48 4 45 7 44 6 876 98 9 00 3 99 6 21 3 23 1 22 2 45 6 47 9 46 8 8 10 00 2 01 9 0011 23 24 11 23 11 47 8 49 11 48 10 8 12 6 01 8 03 3 02 5 24 10 26 9 25 9 49 10 52 1 51 8 15 03 1 04 9 03 11 26 8 28 7 27 7 52 54 4 53 2 817 6 04 7 06 3 05 5 28 6 30 5 29 5 54 2 56 6 55 5 900 06 1 07 9 06 10 30 3 32 3 31 3 56 4 58 9 57 7 926 07 7 09 8 08 4 32 1 34 1 33 1 58 7 60 11 59 9 950 09 10 9 09 10 33 10 35 11 34 10 60 8 63 2 61 11 976 10 6 12 8 111 4 35 8 37 9 36 8 62 11 6f 4 64 1 9 10 11 11 13 9 L12 10 37 6 39 7 d8 6 65 1 67 7 66 4 9 12 6 13 6 15 8 114 4 39 4 41 6 40 4 67 3 69 9 68 6 9 15 14 11 16 9 L15 9 41 1 43 3 42 2 69 5 72 70 8 9 17 6 16 5 18 8 117 3 42 11 45 1 44 71 7 74 2 72 10 JO 17 10 19 9 118 9 44 9 46 11 45 10 73 9 76 6 76 1! MAIN PIPES 275 O K 8 O . Ml l> t> 00 CO I I N g S 38 8 8 $ S"3 ? S S 3 S C3 f ^ o" t>" ^jT c^" cT cT .-trHi-lr-lr-l CO ^^ O3 1O to oo^op^o^i-^ao^ir^ao^o : ! 3gSS1828$Sg . . .co o < O O f C^ i* 00 C^ .O^i IU3dO'^ CNCSr- cuadOtMOooco^rofMr- i(^ II C5 C5 SO t ^H S^So^^oocicoioo^^ OJ CO * O O O < 3 s * , r-T r-Tof co" IQK^CDO 276 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS TABLES Of the Discharge of Gas, in Cubic Feet per hour, through Pipes of various Diameters and Lengths at different Pressures. By THOMAS G. BARLOW. Extended by THOMAS NEWBIGGING. (The specific gravity of the gas is taken at 0-4, air being i.) The tables are calculated according to the formula given by Dr. Pole in his valuable article 1 "On the Motion of Fluids in Pipes." Q = quantity of gas in cubic feet per hour. I = length of pipe in yards. d = diameter of pipe in inches. h .= pressure in inches of water. s = specific gravity of gas, air being i. si i.e., multiply the pressure in inches of water by the diameter of the pipe, also in inches. Divide the product by the specific gravity of the gas multiplied by the length of the pipe in yards. Extract the square root of the quotient, which root, multiplied by the con- stant quantity 1350, and the square of the diameter of the pipe in inches, gives the number of cubic feet discharged in one hour. EXAMPLE. It is required to find the number of cubic feet of gas of the specific gravity of 0-400, which will be discharged in one hour from a pipe 8 in. in diameter and 1250 yards in length, under a pressure of -f-, or i J in. head of water. Thus (h d) = 8 X i'5 = 12. 12 1 , the square root being=o-i549. (1350 ^ V -) = 1350 X 64 x 0-1549 = 13,383 cub. ft. = Q. Recent research work by Professor Unwin on the discharge of gas in pipes revealed the fact that Dr. Pole's formula is not strictly accurate. 1 See King's Treatise, vol. ii., p. 374 et seq. MAIN" PIPES 277 It is well known that Dr. Pole in computing his formula assumed an average coefficient of friction of 0*006, whereas Professor Unwin has, determined that different diameters of pipes have varying coefficients of friction. The following table gives the coefficient of friction based on the formula, /j, = 0*0044 ( i H ), where d is the diameter of the pipe \ 7 d/ in feet, deduced by Professor Unwin. Diameter Coefficient of Main. of Friction. -2- - 2'5 3 'li 9 10 12 0-0082 0-0074 0-0069 0*0063 0-0059 0-0057 0-0055 0-0053 0^0052 0-0051 0-0050 Diameter of Main. Coefficient of Friction. 14 0-0049 15 . 0-0049 16 0-0049 18 0*0048 20 0-0048 22 0-0047 24 0-0047 26 0-0047 28 0-0047 30 - 0-0047 36 0-0044 The difference in the discharge by adopting the new values of friction is, however, not of sufficient importance to annul the values as determined by Dr. Pole. When it is remembered that no theoretical calculation can be strictly accurate under the varying conditions of gas supply, Dr. Pole's formula may be accepted for all practical purposes. [TABLES. 278 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Diameter of Pipe, 0-5 Inch. Length in yards. 10. 20. 80. 50. 75. 100. ICO. Quantity delivered with 0-1 in. pressure. 37-7 26-7 21-7 16-8 13-8 11-9 9 7 0-2 53-4 37-7 30-6 23-8 19-5 16-8 13-8 0-3 65-2 46-3 37-7 29-1 23-8 20-7 16-8 0-4 75-2 53-3 43-2 33-7 27-5 23-8 19-5 0-5 84-3 59'4 48-6 37'4 30-7 26-7 21-7 0-6 92-1 65-1 53-3 41-1 33-7 29-0 23-8 0-8 106-7 75-4 61-4 47-5 38-8 83-7 27-4 i-o 119-1 84-3 68-8 53-3 43-2 87'7 30-8 1-2 130-6 92-1 75-2 58-3 47-5 41-1 33-7 1-5 146-1 103-2 84-3 65-1 63-3 45-9 37-8 1-8 159-9 113-0 92-1 71-5 68-3 50-6 41-1 2-0 168-7 119-1 97-2 75-2 61-4 53-3 43-5 2-5 188-6 133-3 108-6 84-3 68-8 59-4 48-6 Diameter of Pipe, 0*75 Inch. Length in yards. 10. 20. 80. 50. 75. 100. 150. Quantity delivered .vith O'l in. pressure. 104-3 73-8 60-0 46-6 37-9 32-9 26-9 0-2 147-6 104-3 84-9 65-8 53-7 46-6 37-9 0-3 179-9 126-8 104-3 80-9 65-8 57-0 46-6 0-4 207-3 146-5 119-9 93-2 75-9 65-8 53-8 0-5 232-3 164-0 133-6 103-2 04-2 73-8 60-0 0-6 254-3 179-9 146-5 113-9 92-6 79-7 65-3 0-8 293-8 207-3 169-3 131-3 107-0 92-6 75-9 i-o 328-8 232-3 189-8 146-5 119-9 103-2 84-2, 1'2 359-9 2543 207-3 160-9 131*3 113-9 92-6 1-6 402-4 284-0 232-3 179-9 146-5 126-8 108-2 1-8 441-1 311-3 254-3 192-2 160-9 138-9 113-9 2-0 464-7 328-8 268-0 207-8 169-3 146-5 119-9 2'5 5194 367-5 299-9 232-2 189-8 164-0 133-6 Diameter of Pipe, 1 Inch. Length in yards. 10. 20. 80. 50. 75. 100. 150. Quantity delivered with O'l in. pressure, 214-0 151-0 124-0 95-0 78-0 67-0 55-0 0-2 302-0 214-0 175-0 135-0 110-0 95-0 78-0 0-3 368-5 260-6 214-0 165-0 185-0 117-0 95-0 0-4 426-6 301-0 245-7 190-0 156-0 135-0 110 0-5 476-6 387-6 274-0 213-3 172-8 151-0 123-0 0-6 522-4 368-5 301-0 233-5 190-8 164-7 135-0 0-8 603-4 426-6 348-3 270-0 220-0 190-3 155-2 1-0 675-0 476-5 388-8 301-0 245-7 213-3 172-8 1-2 738-4 522-4 426-6 329-4 270-0 233-5 190-3 1-5 826-2 684-6 476-5 368-5 301-0 260-5 213-3 1-8 904-6 639-9 622-4 405-0 329-4 286-2 233-5 2-0 954-4 675-0 650-8 426-6 348-3 301-0 245-7 2-6 1,066-5 754-6 615-6 476-6 388-8 337-6 274-0 MAIN -PIPES 279 Diameter of Pipe, 1-25 Inches. Length in yards. 25. 60. 75. 100. 150. 200. 800. Quantity delivered with O'l in. pressure. 236-0 167-0 137-0 118-0 96-0 84'0 68-0 0-2 333-0 236-0 192-0 167-0 137-0 118-0 96-0 0'3 407-1 289-0 236-0 205-0 167-0 144-0 118-0 0-4 470-3 333-2 272-1 236-0 192-0 167-0 137-0 0-5 527-3 371-2 303-7 263-6 215-1 187-0 152-0 0-6 575-8 407-1 333-2 286-8 235-8 203-9 166-6 0-8 666-5 470-3 383-9 333-2 272-1 235-8 192-3 1-0 744-6 627-3 430-3 371-2 303-7 263-6 215-1 1-2 816-3 575-8 470-3 407-1 333-2 286-8 235-8 1-5 913-3 645-4 627-3 455-6 371-2 322-7 263-6 1-8 999-8 706-4 676-8 499-9 407-1 352-2 286-8 2-0 1,054-6 744-6 607-5 527-3 430-3 371-2 303-7 2-5 , 1,179-1 833-2 679-2 588-5 480-9 415-5 339-fi Diameter of Pipe, 1-5 Inches. Length in yards. 25. 50. 75. 100. 150. 200. | 800. Quantity delivered with O'l in. pressure. 374-0 264-0 215-0 187-0 152-0 332-0 107-0 0-2 528-0 374-0 304-0 264-0 215-0 187-0 152-0 03 643-9 458-0 374-0 322-0 264-0 229-0 187-0 0-4 741-1 525-4 428-2 374-0 304-0 264-0 215-0 0-5 829-2 586-2 479-9 413-1 339-5 295-0 239-0 0-6 911-2 643-9 525-4 455-6 870-5 321-9 261-2 0-8 1,050-9 741-1 607-5 625-4 428-2 370-5 303-7 i-o 1,175-5 829-2 677-3 686-2 479-9 413-1 339-5 1-2 1,287-9 911-2 741-1 643-9 625-4 455-6 370-5 1-6 1,439-7 1,017-5 829-2 719-8 586-2 607-2 413-1 1-8 1,576-4 1,114-7 911-2 789-1 643-9 555-8 455-6 2-0 1,661-5 1,175-5 959-8 829-2 677-3 586-2 479-9 2-5 1,858-9 1,315-2 1,072-2 929-4 759-3 656-1 634-6 Diameter of Pipe, 2 Inches. Length in yards. 50. 75. 100. 150. 200. 800. 500. Quantity delivered with O'l in. pressure. 640 441 381 811 270 220 170 0-2 763 623 540 441 381 311 241 03 934 763 665 540 468 381 296 0-4 1,080 880 761 623 540 441 341 0-5 1,204 983 853 697 604 492 381 0-6 1,318 1,080 934 761 659 540 416 0-8 1,523 1,242 1,080 880 761 621 481 i-o 1,706 1,393 1,204 983 853 697 540 1-2 1,868 1,523 1,318 1,080- 934 761 589 1-5 2,090 1,706 1,474 1,204 1,042 853 659 1-8 2,290 1,868 1,620 1,318 1,145 934 724 2-0 2,414 1,971 1,706 1,393 1,204 983 761 2-6 2,700 2,203 1,906 1,555 1,350 1,102 853 28o NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Diameter of Pipe, 2 '5 Inches. Length in yards. 60. 75. 14)0. 150. 200. 800. 500. Quantity delivered with 0-1 in. pressure. 943 770 667 545 471 335 298 0-2 1,335 1,090 943 770 667 545 421 0-3 1,628 1,335 1,172 943 819 667 616 0-4 1,882 1,540 1,333 1,090 943 770 696 0-5 2,109 1,721 1,485 1,215 1,056 861 667 0'6 2,803 1,882 1,628 1,333 1,148 943 781 0-8 2,666 2,177 1,882 1,540 1,333 1,088 844 1-0 2,978 2,430 2,109 1,721 1,485 1,215 943 1-2 3,265 2,666 2,303 1,882 1,628 1,333 1,029 1-5 3,653 2,978 2,582 2,109 1,823 1,485 1,148 1-8 3,999 3,265 2,827 2,303 2,000 1,628 1,266 3-0 4,219 8,443 2,978 2,430 2,109 3,721 1,333 *6 4,717 3,848 3.338 2,717 2,354 1,924 1,485 Diameter of Pipe, 3 Inches. Length in yards. 100. 150. 250. 500. 750. 1 1000. 1260. Quantity delivered with O'l in pressure. 1,054 859 666 471 384 333 298 0-2 1,440 1,214 942 666 543 471 375 0-3 1,823 1,487 1,153 815 666 676 529 0'4 2,102 1,713 1,332 942 768 666 696 0-5 2,345 1,920 1,482 1,054 859 744 666 0-6 2,576 2,102 1,628 1,152 942 815 739 0-8 2,965 2,480 1,882 1,324 1,081 942 845 i-o 8,317 2,709 2,102 1,482 1,215 1,052 942 1'2 3,645 2,965 2,296 1,628 1,324 1,152 1,030 1-5 4,070 3,317 2,576 1,823 1,482 1,288 1,152 1-8 4,459 3,645 2,819 1,993 1,628 1,409 1,262 2-0 4,702 3,839 2,965 2,102 1,713 1,482 1,324 2-6 6,261 4,289 3,317 2,345 1,920 1,652 1.482 Diameter of Pipe, 4 Inches. Length in yards. 100. 250. 500. 750. 1000. 1250. 1500. Quantity delivered with O'l in pressure. 2,160 1,366 966 788 683 611 557 0-2 8,054 1,932 1,366 1,114 966 864 788 0-3 3,737 2,366 1,673 1,366 1,183 1,058 966 0-4 4,320 2,722 1,932 1,576 1,366 1,222 1,114 0-5 4,817 3,046 2,160 1,761 1,526 1,366 1,245 0-6 6,270 8,346 2,354 1,932 1,672 1,496 1,366 0-8 6,091 8,845 2,722 2,225 1,932 1,728 1,576 1-0 ;, 6,826 4,320 3,046 2,484 2 V 160 1,932 1,761 1-2 t 7,474 4,730 3,346 2,722 2,354 2,115 1,922 1-5 8,359 6,270 3,737 3,046 2,635 2,354 2,160 1-8 it 9,168 6,789 4,082 3,346 2,894 2,592 2,354 2'0 9,655 6,091 j 4,320 3,521 3,046 2,722 2,484 2-5 10,800 6,826 i 4.817 3,931 8,413 3,046 2,786 MAIN PIPES 281 Diameter of Pipe, 5 Inches. Length in yards. 100. 250. 500. 750. 1000. -125(L. - 1500* . Quantity delivered with O'l in. pressure. 8,540 2,245 1,687 1,296 1,122 1,000 910 0'2 5,005 3,174 2,245 1,832 1,587 1,414 1,296 0-3 6,514 3,888 2,748 2,245 1,943 1,732 1,575 0-4 7,526 4,769 3,174 2,592 2,245 2,000 1,820 0-5 8,438 5,833 3,773 2,888 2,508 2,236 1,934 0-6 9,214 5,839 4,118 3,174 2,748 2,449 2,245 0-8 10,665 6,750 4,759 3,881 3,174 2,828 2,596 1-0 11,914 7,526 5,333 4.354 3,773 3,174 2,877 1-2 13,061 8,235 6,839 4,759 4,118 3,679 3,375 If 14,614 9,214 6,514 5,333 4,590 4,118 3,640 1-8 15,998 10,125 7,166 5,839 6,063 4,523 4,118 2-0 16,875 10,665 7,626 6,143 5,333 4,759 4,354 2-5 18,866 11,914 8,438 6,885 5,940 5,333 4,860 Diameter of Pipe, 6 Inches. Length in yards. 250. 500. 750. 1000. 1250. 1500. 1750. Quantity delivered with 0*1 in. pressure. 3,770 2,660 2,170 1380 1,680 1,530 1,420 0-2 ^ 5,320 3,770 3,130 2,660 2,370 2,170 2,010 0-3 6,530 4,620 3,770 3,270 2,920 2,660 2,460 0-4 7,640 5,320 4,340 3,770 3,360 3,060 2,840 0-5 8,408 5,970 4,860 4,210 3,770 3,430 3,180 0-6 9,185 6,512 5,320 4,620 4,130 3,770 3,460 0-8 10,643 7,528 6,124 5,320 4,740 4,340 4,020 i-o 11,858 8,408 6,853 5,929 6,320 4,860 4,500 1-2 13,025 9,185 7,528 6,512 5,832 5,297 4,929 1-5 14,580 10,303 8,408 7,290 6,512 5,970 6,500 1-8 15,941 11,275 9,185 7,970 7,139 6,512 6,026 2-0 16,816 11,858 9,720 8,408 7,528 6,853 6,360 2'5 18,808 13,268 10,838 9,380 8,408 7,679 7,096 Diameter of Pipe, 7 Inches. Length in yards. 250. 500. 750. 1000. 1250. 1500. 1750. Quantity delivered with O'l in. pressure. 5,560 3,920 3,200 2,780 2,470 2,270 2,100 0-2 7,840 5,560 4,510 3,920 3,500 3,200 2,960 0-3 9,600 6,800 6,560 4,800 4,300 3,920 3,640 0'4 11,120 7,840 6,400 5,560 4,940 4,540 4,200 0'5 12,370 8,750 7,180 6,200 5,560 5,060 4,680 0-6 13,554 9,585 7,840 6,800 6,080 5,560 5,130 0-8 15,611 11,047 8,996 7,840 7,020 6,400 5,930 1-0 17,463 12,370 10,054 8,732 7,840 7,180 6,610 1-2 19,170 13,554 31,047 9,585 8,533 7,805 7,210 1-5 21,433 15,148 12,370 10,716 9,585 8,750 8,120 3-8 23,477 16,597 13,554 11,709 10,452 9,855 8,864 2-0 24,740 17.463 14,288 j 12,370 11,047 j 10,054 9,360 2-5 27,651 19,567 15,942 13,825 12,370 I 11,292 10,452 1 1 282 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Diameter of Pipe, 8 Inches. Length in yards. 250. 500. 750. 1000. 1250. 1500. 1750. Quantity delivered with O'l in. pressure. 7,760 5,470 4,470 3,880 3,460 3,160 2,920 0-2 10,940 7,760 6,310 5,470 4,880 4,470 4,180 0-3 13,400 9,450 7,760 6,700 5,980 5,470 5,050 0-4 15,520 10,940 8,940 7,760 6,920 6,320 5,840 0-5 17,280 12,200 9,900 8,640 7,760 7,020 6,520 0-6 18,922 13,383 10,940 9,450 8,480 7,760 7,150 0-8 21 ,851 15,379 12,614 10,940 9,780 8,940 8,260 1-0 24,365 17,280 14,083 12,182 10,940 9,900 9,237 1-2 26,767 18,922 15,379 13,883 11,923 10,886 10,109 1-5 29,894 21,082 17,280 14,947 13,883 12,200 11,300 1'8 32,746 23,155 18,922 16,330 14,602 13,383 12,355 2-0 34,560 24,365 19,872 17,280 15,379 14,083 13,040 2-5 38,621 27,302 22,291 19,267 17,280 15,725 14,602 Diameter of Pipe, 9 Inches. Length in yards. | 250. 500. 750. 1000. 1250. 1500. 1750. Quantity delivered with O'l in. pressure. 10,400 7,380 6,350 5,200 4,650 4,250 3,950 0-2 14,760 10,400 8,500 7,380 6,480 6,000 5,620 0-3 18,000 12,780 10,400 9,000 8,300 7,380 6,800 0-4 20,800 14,760 12,700 10,400 9,300 8,500 7,900 0-5 23,182 16,500 13,420 11,900 10,400 9,680 8,800 06 25,369 17,933 14,760 12,780 11,400 10,400 9,650 0-8 29,306 20,667 16,938 14,760 13,100 12,000 11,050 1-0 32,805 23,182 18,918 16,403 14,760 13,420 12,380 1-2 85,867 25,369 20,667 17,933 16,064 14,653 13,559 1-6 40,131 28,409 23,182 20,011 17,933 16,500 15,200 1-8 43,959 31,055 25,369 21,979 19,683 17,933 16,621 2-0 46,364 32,805 26,681 23,182 20,667 18,918 17,600 2-5 51,332 36,632 29,853 25,916 23,182 21,105 19,574 Diameter of Pipe, 10 Inches. Length in yards. 500. 750. 1000. 1250. 1500. 1750. 2000. Quantity delivered with O'l in. pressure. 9,560 7,800 6,750 6,050 6,520 5,100 4,780 0'2 13,500 11,040 9,560 8,520 7,800 7,300 6,750 0-3 16,500 13,500 11,700 10,520 9,560 8,850 8,259 0-4 19,120 15,600 13,500 12,100 11,040 10,200 9,560 0'5 21,300 17,400 15,050 13,500 12,380 11,400 10,650 0-6 23,355 19,120 16,500 14,800 13,500 12,500 11,650 0-8 27,000 22,005 19,120 17,050 15,600 14,400 13,500 1-0 30,105 24,570 21,330 19,120 17,400 16,150 15,050 1-2 32,940 27,000 23,355 20,911 19,035 17,550 16,578 1-5 36,855 30,105 26,055 23,355 21,300 19,600 18,500 1-8 - 40,500 32,940 28,620 25,515 23,365 21,600 20,250 20 42,660 34,830 30,105 27,000 24,570 22,800 21,300 2-5 47,655 38,880 33,750 30,105 27,540 25,501 23,760 MAIN PIPES 283 Diameter of Pipe, 12 IncJies. Length in yards. 500. 750. 1000. 1250. 1500. 1750. 9000. Quantity delivered with O'l in. pressure. 15,100 12,300 10,700 9,550 8,700 8,050 7,550 0-2 21,400 17,400 15,100 13,450 12,300 11,350 10,700 0-8 26,100 21,400 19,500 16,500 15,100 13,880 13,050 0-4 30,200 24,600 21,400 19,100 17,400 16,100 15,100 or, 33,600 27,500 23,800 21,400 19,440 18,050 16,800 00 86,741 30,200 26,100 23,300 21,400 19,800 19,500 09 42,573 34,603 30,200 26,900 24,600 22,700 21,400 i-o 47,433 38,880 33,631 30,200 27,500 25,450 23,800 1'2 52,099 42,573 36,741 32,853 30,112 27,799 26,049 I'fi 58,320 47,433 41,212 36,741 33,600 31,250 29,250 1-8 63,763 52,099 45,100 40,396 36,741 34,020 31,881 2-0 67,262 54.820 47,433 42,573 38,880 36,100 33,600 2'6 75,232 61,430 53,071 47,433 43,351 40,240 37,519 Diameter of Pipe, 14 Inches. Length in yards. 600. 750. 1000. 1250. 1500. 1750. 2000. Quantity delivered. with 01 in. pressure. 22,100 18,100 15,600 13,950 12,750 11,800 11,050 0-2 31,200 25,500 22,100 19,800 18,100 16,700 15,600 0-3 38,400 31,200 27,100 24,250 22,100 20,500 19,200 0-4 44,200 36,200 31,200 27,900 25,500 23,600 22,100 0-5 49,400 40,400 35,000 31,200 28,500 26,460 24,700 06 54,216 44,200 38,400 34,300 31,200 28,900 27,100 08 62,445 51,067 44,200 39,600 36,200 33,400 31.200 1-0 69,854 57,153 49,480 44,200 40,400 37,300 85;000 1-2 76,681 62,445 54,216 48,421 44,188 40,986 38,340 1-5 85,730 69,854 60,593 54.216 49,400 45,700 42,600 18 93,906 76,681 66,414 59,270 54,216 50,009 46.834 2-0 98,960 80,703 69,854 62,445 57,153 52,920 49;400 2-5 110,602 90,228 78,268 69,854 63,768 59,005 55,301 Diameter of Pipe r 15 Inches. Length in yards. 600. 750, 1000. 1250. 1500. 1750. 2000. Quantity delivered. with O'l in. pressure. 26,300 21,400 18,600 16,600 15,200 14,000 13,150 0-2 37,200 30,400 26,300 23,500 21,400 19,900 18,600 03 45,500 37,200 32,250 28,750 26.30C 24,300 22,750 0-4 52,600 42,800 37,200 33,200 30,400 28,000 26,300 0-5 58,700 48,000 41,600 37,200 34,000 31,400 29,350 06 64,395 52,600 45,500 40,700 37,200 34,450 32,250 0-8 74,115 60,750 52,600 47,000 42,800 39,800 37;200 i-o 82,923 67,736 58,623 52,600 48,000 44,400 41,600 1-2 91,125 74,115 64,395 57,408 52,548 48,600 45,562 1-5 101,756 82,923 71,983 64,395 58,700 54,300 60,800 1-8 111,476 91,125 78,914 70,470 64,395 59,535 65,586 2-0 117,551 95,985 82,923 74,115 67,736 62,800 68,700 2-5 131,523 1 107,223 92,947 82,923 75,937 70,166 65,610 284 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Diameter of Pipe, 16 Inches. Length in yards. 600. 750. 1000. 1250. 1500. 1750. 2000. Quantity delivered. with O'l in. pressure. 31,000 25,250 21,850 19,550 17,850 16,550 15,500 02 43,700 35,700 31,000 27,700 25,250 23,400 21,850 0-3 53,600 43,700 38,100 34.000 31,000 28,700 26,800 0-4 62,000 50,500 43,700 39,100 35,700 33,100 31,000 0-5 69,120 56,600 49,000 43,700 39,900 37,150 34,560 06 75,686 62,000 53,600 47,900 43,700 38,100 40,700 0-8 87,402 71,193 62,000 55,400 50,500 46,800 43,700 i-o 97,459 79,488 69,120 62,000 56,600 52,400 49,000 T2 107,066 87,402 75,686 67,703 61,516 57,024 53,533 1-5 119,577 97,459 84,326 75,686 69,120 63,900 60,100 1-8 130,982 107,066 92,620 82,944 75,686 70,087 65,318 20 138,240 112,665 97,459 87,402 79,488 74,300 69,120 2-5 154,483 126,144 109,209 97,459 89,164 82,598 77,068 Diameter of Pipe, 18 Inches. Length in yards. 500. 750. 1000. 1500. 2000. 2500. 3000. Quantity delivered with O'l in. pressure. 41,400 33,800 29,400 23,900 20,700 18,400 16,900 0-2 58,800 47,800 41,400 33,800 29,400 26,200 23,900 0-3 71,800 58,800 50,800 41,400 35,900 32,100 29,400 0-4 82,800 67,600 58,800 47,800 41,400 38,800 33,800 0-5 92,600 75,700 65,600 53,500 46,300 41,400 37,850 0-6 101,476 82,800 71,800 58,800 50,800 45,400 41,400 0-8 117,223 95,790 82,800 67,600 58,800 52,300 47,800 ro 131,220 106,725 92,728 75,700 65,600 58,800 53,500 1-2 143,467 117,223 101,476 82,668 71,733 64,254 58,611 1-5 161,400 131,220 113,636 92,728 80,000 71,800 65,600 1-8 175,834 143,467 124,221 101,476 87,917 78,732 71,733 2-0 185,457 151,340 131,220 106,725 92,728 82,800 75,700 2-5 207,327 169,273 146,529 119,410 103,663 92,728 84,500 Diameter of Pipe, 20 Inches. Length in yards. 500. 750. 1000. 1500. 2000. 2500. 3000. Quantity delivered with 0-1 in. pressure. 54,000 44,000 38,250 ! 31,200 27,000 24,200 22,000 1 0-2 76,600 62,400 64,000 44,000 38,250 34,200 31,200 0-3 93,500 76,500 66,100 54,000 46,750 41,800 38,250 0-4 108,000 88,000 76,500 62,400 54,000 48,400 44,000 0-5 120,600 98,800 85,300 69,800 62,250 54,000 49,400 0-6 131,760 108,000 93,500 76,500 66,100 59,100 54,000 - 0-8 152,280 124,200 108,000 88,000 ! 76,500 68,400 62,400 1-0 170,640 139,320 120,420 98,800 85,300 76,500 69,800 1-2 186,840 152,280 131,760 108,000 93,420 83,646 76,140 1-5 208,980 170,640 147,420 120,420 102,300 93,500 85,300 1-8 228,960 186,840 162,000 131,760 114,480 102,060 93,420 2-0 241,380 197,100 170,640 139,320 120,420 108,000 98,800 2-5 1 270,000 220,320 190,620 155,520 135,000 120,420 110,200 MAIN PIPES 285 Diameter of Pipe, 22 Indies. Length in yards. 500. 750. 1000. 1500. 2000. 2500. 3000. Quantity delivered with O'l in. pressure. 68,600 56,000 48,400 39,600 84,300 80,700 28,000 0-2 96,800 79,200 68,600 56,000 48,000 43,400 39,600 81 118.800 96,800 84,000 68,600 59,400 53,300 48,400 n* 137,200 112,000 96,800 79,200 68,600 61,400 56,000 153,500 122,500 108,200 88,600 76,800 68,400 61,200 n 06 ., 168,577 137,200 118,800 96,800 84,000 75,000 68,600 ?n 193,406 158,122 137,200 112,000 96,800 86,500 79,200 \1 216,275 176,418 152,895 122,500 108,200 96,800 88,600 1-2 237,184 193,406 168,577 136,560 118,265 105,850 96,703 T 265,280 216,275 187,525 152,895 132,000 118,800 108,200 in 290,697 237,184 203.860 168,577 145,054 130,026 118,265 o'2 306,444 249,598 216,275 176,418 152,895 137,200 122,500 2-5 342,381 279,655 242,280 197,326 171,190 152,895 140,000 Diameter of Pipe, 24 Inches. Length in yards. 500. 750. 1000. 1500. 2000. 2500. SOOO. Quantity delivered with O'l in. pressure. 84,000 68,600 59,500 48,500 42,000 37,500 34,300 0-2 119,000 97,000 84,000 68,600 59,500 53,400 48,500 0-3 145,500 119,000 103,000 84000 72,700 65,200 59,500 0-4 ; 168,000 137,200 119,000 97,000 84,000 75,000 68,600 0-5 187,500 155.000 135,600 108,600 93,800 84,000 77,500 0-6 208,396 168,000 145,000 119,000 103,000 92,000 84,000 0-8 240,900 196,655 168,000 137,200 119,000 106,000 97,000 1-0 269,049 219,283 189,734 155,000 135,600 119,000 108,600 1-2 294,710 240,900 208,396 170,294 146,966 131,414 120,450 1-5 329,702 269,049 233,280 189,734 163,000 145,500 135,600 1-8 360,806 294,710 255,052 208,396 180,403 161,585 146,966 2-0 380,946 311,040 269,049 219,283 189,734 168,000 155,000 2-5 425,347 347,587 300,931 245,721 212,284 189,734 172,000 Diameter of Pipe, 26 Inches. Length in yards. 750. 1000. 1500. 2000. 2500. 3000. 4000. Quantity delivered with O'l in. pressure. 85,000 73,500 60,000 52,000 46,500 42,500 36,750 0-2 120,000 104,000 85,000 73,500 65,800 60,000 52,000 08 147,000 127,000 ! 104,000 90,000 80,600 73,500 63,500 0-4 170,000 147,000 120,000 104,000 93,000 85,000 73,500 0-5 189,000 165,000 134,000 116,000 104,000 94,500 82,500 0-6 208,000 180,000 147,000 127,000 114,000 104,000 90,000 0-8 240,013 208,000 170,000 147,000 132,000 120,000 104,000 i-o 268,304 232,621 189,000 165,000 147,000 134,000 116,000 1-2 293,857 I 254,615 208,072 179,782 160,617 146,928 126,851 1-6 328,536 284,731 232,621 201,000 180,000 165,000 142,000 1-8 360,385 312,109 254,615 220,666 197,121 179,782 156,054 2-0 379,641 328,536 268,304 232,621 208,000 189,000 165,000 2'5 424,359 367,777 300,245 260,091 232,621 213,000 184,000 3-0 465,334 402,456 328,536 284,731 254,615 232,621 201,000 286 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Diameter of Pipe, 28 Inches, Length iu yards. 1000. 1500. 2000. 2500. 8000. 4000. 5000. Quantity delivered with 05 in. pressure. 198,000 161,000 140,000 125,000 114,500 99,000 88,600 06 ' 216,866 176,752 153,362 136,533 124,891 107,956 96,314 08 249,782 204,271 176,752 157,701 143,942 124,891 111,978 10 280,000 229,000 198,000 177,000 161,000 140,000 125,000 1-3 306,724 249,782 216,866 193,687 176,752 153,362 136,533 16 342,921 280,000 241,000 216,000 198,000 171,000 153,500 13 375,626 306,724 265,658 237,081 216,866 187,336 167,227 20 395,841 322,812 280,000 250,000 229,000 198,000 177,200 25 442,411 360,914 313,074 280,000 255,000 222,000 198,000 30 484,747 395,841 342,921 306,724 280,000 241,000 216,000 Diameter of Pipe, 80 Inches. Length in yards. 1000. 2000. 8000. 4000. 5000. 7500. 10000. Quantity delivered with 0*5 in. pressure. 234,000 166,000 135,000 117,000 105,000 86,000 74,500 0-6 257,580 182,250 148,230 128,790 115,182 94,041 81,405 0-8 296,460 210,195 171,315 148,230 132,435 108,135 94,041 i-o 332,000 234,000 192,000 166,000 149,000 121,500 105,000 1-2 364,500 257,580 210,195 182,250 162,810 132,435 115,182 1-5 407,025 287,000 234,000 203,000 182,000 149,000 128,500 1-8 445,905 315,657 257,580 222,345 199,260 162,810 140,940 20 470,205 331,695 270,000 234,000 210,000 172,000 149,000 25 526,095 371,790 303,750 263,000 234,000 192,000 166,000 30 575,910 407,025 331,695 287,955 257,000 210,000 182,000 40 664,605 470,205 383,940 331,695 298,000 243,000 21(3,000 Diameter of Pipe, 36 Inches. Length in yards. 1000. 2000. 3000. 4000. 5000. 7500. 10000. Quantity delivered with 0'5 in, pressure. 370,915 262,440 213,451 185,457 165,862 135,419 117,223 06 405,907 286,934 234,446 202,953 181,783 148,366 127,720 0-8 468,892 330,674 271,013 234,446 209,952 171,285 148,366 10 530,000 370,000 303,000 265,000 234,000 192,000 166,000 1-2 573,868 405,907 330,674 286 t 934 257,016 209,952 181,783 1-5 642,103 456,000 372,000 322,000 288,000 234,900 204,000 1-8 703,339 496,886 405,907 351,669 314,928 257,016 222,199 20 741,830 524,880 428,000 372,000 332,000 271,000 234,000 2-5 829,310 586,116 477,640 416,000 372,000 303,000 265,000 3-0 908,042 642,103 524,880 454,546 407,000 332.000 288,000 40 1,049,760 742,180 605,361 524,880 468,892 384;000 332,000 The foregoing tables are calculated upon the basis of the specific gravity of the gas being 0*400. The quantity of gas of any other specific gravity discharged may be ascertained by multiplying the quantity indicated in the table by 0*6325 (the square root of 0*400), and dividing by the square root of the specific gravity of the other gas. MAIN PIPES 287 EXAMPLE. If a 12-in. pipe, 1000 yds. long, discharges 23,800 cub. ft. of gas per hour, specific gravity 0*400 at 0*5 in. pressure, how much gas will the same pipe discharge, at the same pressure, when the specific gravity is 0*560 ? 33.800x0-6325 I6cub>ft 07483 The quantity of gas discharged at any other pressure may be ascertained by multiplying the quantity indicated in the table by the square root of the new pressure, and dividing by the square root of the original pressure. EXAMPLE. If a quantity of gas equal to 23,355 cub. ft. is discharged in one hour at a pressure of i'2 in., what quantity will be discharged through the same pipe at 2 '2 in. pressure ? 2 3.355 X 1-4832 6 ft 1*0954 To facilitate these calculations tables are annexed of the square roots of specific gravities from 0*350 to 0700, rising 0*005 at a time ; and of the square roots of pressures from yo of an inch to 4 in., rising y 1 ^ at a time. TABLE. Square Root of the Specific Gravity of Gas from 850 to 700. Specific Gravity. Square Root. Specific Gravity. Square Boot. Specific Gravity Square Hoot. Specific Gravity. Square Root. Specific Gradty Square Root. 350 5916 425 6519 495 7035 565 7517 635 7969 355 5958 430 6557 500 7071 570 7549 640 8000 360 6000 435 6595 505 7106 575 7583 645 8031 365 6041 440 6633 510 7141 580 7616 650 8062 370 6083 445 6671 515 7176 585 7648 655 8093 375 6124 450 6708 620 7212 590 7681 660 8124 380 6164 455 6745 525 7246 595 7713 665 8156 385 6205 460 6782 530 7280 600 7746 670 8185 390 6245 465 6819 535 7314 605 7778 675 8216 395 6285 470 6856 540 7348 610 7810 680 8246 400 6325 475 6892 545 7382 615 7842 685 8276 405 6364 480 6928 550 7416 620 7874 690 8306 410 6403 485 6964 555 7449 625 7905 695 8337 415 6442 490 '7000 560 7483 630 7937 700 8367 420 6481 288 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS TABLE. Square Root of Pressures, rising by Tenths of an Inch, from One-tenth to Four Inches. H Inches and Tenths. Square Root. Inches and Tenths. Square Root. Inches and Tenths. Square Root. 0*1 0-3162 1-5 1-2251 ,8 1-6733 0-2 0-4472 1*6 1*2649 i 2*9 1*7029 o'3 0-5477 i - 7 1*3038 3-0 1-7320 0*4 0-6324 r8 1-3416 3*1 1-7606 0-5 0-7071 1*9 3*2 1-7888 0*6 0-7745 2-0 1*4142 3-3 1-8165 0*7 0*8366 2*1 1-4491 3-4 I-8439 o'8 0-8944 ; 2*2 1*4832 1*8708 0*9 0-9487 2'3 1-5165 3*6 I-8973 I*O I'OOOO 2-4 i-349i 3'7 1-9235 1*1 1-0488 2*5 1*5811 3"8 1*9493 1*2 1*0954 2*6 1*6123 3'9 1-9748 I"3 1*1401 2*7 1*6431 4*0 2"OOOO 1*4 1*1832 j Should it be required to find the pressure in inches of water to discharge a certain quantity of gas of given specific gravity in an hour, through a pipe the dimensions of which are known, the formula is (1350)2 & i.e., multiply the square of the number of cubic feet of gas to be discharged in one hour by the specific gravity of the gas, and by the length of the pipe in yards ; divide the product by the square of the constant number 1350, multiplied by the diameter in inches raised to the fifth power, and the quotient is the pressure. EXAMPLE. It is required to find the pressure in inches of water to discharge in an hour 12,000 cub. ft. of gas, specific gravity 0-5, through a pipe 8 in. in diameter and 1900 yards long. Then Q 2 X s x I _i44,ooo,ooo x 0-5 x 1900 136,800,000,000 (2 -3 in., i35o 2 X d 5 ~ 1,822,500 X 32,768 X 59,719,680,000 (nearly. If the diameter of a pipe is required which will discharge a given quantity of gas under a given pressure, we have the formula -A/"'Q a ^ v /_ _ . A v o MAIN PIPES 289 This can be easily calculated by a table of logarithms thus : log. d = i (2 log. Q + log. s + log. / 2 log. 1350 log. h.) EXAMPLE. It is required to find the diameter of a pipe 1240 yds. long, to discharge 48,000 cub. ft. of gas, of the specific gravity 0*4, in one hour, with a pressure of 2 in. Then 2 log. Q = 2 log. 48,000 . . = 9-3624824 log. s == log. 0-4 ... .. ' . . = T-6o2o6oo log./ = log. 1240 . . . = 3'<>9342i7 12-0579641 2 log. I35O = 6*2606676 ") log. h = log. 2 P* 0-30I0300 5 6-5616976 5 ) 5*4962665 log. d .; . . . . = 1-0992533 Therefore d 13 in. The following axioms are worth remembering : 1. The discharge of gas will be doubled when the length of the pipe is only J of any of the lengths given in the tables. 2. The discharge of gas will be only J when the length of the pipe is four times greater than the lengths given in the tables. 3. The discharge of gas will be doubled by the application of four times the pressure. Handy Rule for finding (approximately) the Content of a Pipe in Gallons and Cubic Feet. RULE. Multiply the square of the diameter of the pipe in inches by the length in yards, and divide by 10 for gallons and by 60 for cubic feet. EXAMPLE A pipe is 6 in. diameter and 400 yds. long, what is the content ? then 62 x 400 "^ I0 ^ I44 als ' ~ 60 = 240 cub. ft. u NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS SERVICE PIPES AND FITTINGS. In the term service pipes are included all pipes branching out of the mains to consumers' meters, and for the supply of public and private lamps. Leakage or unaccounted-for gas is due more to defects in service pipes than to all the other causes combined. The leaks are chiefly caused in the pipe by corrosion, or at its junction with the main. Such being the case, it is clear that the utmost care should be devoted to the habilitation and maintenance of this portion of the distributory plant. Service pipes are of cast-iron, wrought-iron, steel and lead. The use of cast-iron pipes for this purpose is, as a general rule, con- fined to the supply of gas to large establishments, where the diameter of the pipe required exceeds 2 in. The smaller sizes of cast-iron are too fragile to bear the overhead traffic, and the number of joints is objectionable. Such services as are of less bore than 3 in. are usually of wrought-iron or lead. Wrought-iron pipes or tubes are chiefly employed for services. They can be obtained of any convenient length, and are easily and expeditiously fixed. Wrought-iron tubes and fittings, such as tees, bends, elbows, ferrules, sockets, etc., should be perfectly cylindrical, with no ribs or flat places, and internally as smooth as possible. The welding should be scarcely discernible from the other parts, and the screw should be equally deep throughout the thread. In laying wrought-iron pipes, the coupling or socket at the end, and which is supplied along with the pipe, should always be removed, the thread painted with red or white lead paint, and then replaced. Lead pipes have their advantages, though they require more care in laying ; and to prevent their sagging in the ground, wood lags have to be placed underneath them throughout their length. On the other hand, they can be laid with fewer joints ; the only jointing places being the connections with the main and the meter, unless the premises to be supplied is beyond the ordinary distance from the main. When taken up, also, to be renewed the old metal is of more value than old iron. All service pipes, whether of wrought-iron or lead, when laid SERVICE PIPES AND FITTINGS 291 in the ground, should be protected from the oxidizing influences of the soil, moisture, and air, by being encased in a LJ -shaped or V-shaped channel of wood or other material, filled, after the pipe has been laid therein, with a mixture of hot pitch and tar. This prolongs their life indefinitely, and prevents leakage, and con- sequently is well worth the trifling extra cost and trouble entailed. It is not possible always to see whether a wrought-iron service pipe is worn out or not, unless it is taken up out of the ground. The under part of the pipe will often be found completely oxidized when the upper surface is sound and good. The rust forms a shell which crumbles on being disturbed, but when untouched is sufficient to prevent the immediate escape of gas. The tinning or galvanizing of the surface of wrought-iron pipes adds greatly to their durability in sandy soil impregnated with saline matter. Various processes have been devised for covering iron with a thin layer of oxide to protect it from corrosion either in the soil or when exposed to the atmosphere, and they are peculiarly valuable when applied to wrought-iron tubes and fittings. Mains should be drilled, not cut with a chisel, for the insertion of service pipes. The full sectional thickness of the metal is thus preserved, and the hole is a true circle in form. Several makers supply drilling apparatus which secures im- munity from leakage in attaching the service pipe to the main, and it is easily applied and used. All service pipes should, if possible, be laid with a slight fall to the main to admit of the condensed moisture draining away thereto. When the pipe is of great length, and a continuous inclination to the main is impracticable, a small drip- well, com- monly called a bottle-syphon (Fig. 30, on p. 295), should be attached at the lowest point. The service cleansers of D. Hulett & Co. (Fig. 152), of W. & B. Cowan (Fig. 153;, and of Hutchinson Bros. (Fig. 154), are exceedingly useful for removing water and other obstructions from service pipes. u 2 292 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS All abrupt angles, such as square elbows, whether in mains, services, or internal fittings, owing to the resistance they offer to the regular and even flow of the gas, act as condensers, and diminish the available pressure. Their use should, therefore, be discarded wherever practicable ; bends or round elbows being much more preferable. For the same reason the internal surface of pipes should be as smooth as possible. No pipe should be put FIG. 153. FIG. 154. in use without careful examination and the removal of all existing roughnesses. 2-in. cast-iron pipes as mains, J-in. wrought-iron pipes as services, and J-in. lead or composition pipes for internal supply, should be utterly abandoned. The first are a grievous source of direct leakage, owing to breakages at their junction with the service pipes ; the whole three, if used to any great extent, entail high initial pressure, which is synonymous with a heavy leakage account. If the distance from the main to the meter does not exceed SERVICE PIPES AND FITTINGS 293 30 yds., the following sizes of service pipes will supply the number of lights named : i to 9 lights (consuming, say, 4 cub. ft. per hour each) J in. 10 16 M 15 2O 30 60 ,, 50 80 90 ,, 120 130 H 150 200 300 400 500 60O 7OO 1000 3 >' 4 " " 5 6 ,, 6 ,, 7 tt O ,, The above sizes allow for partial contraction of the area of the pipe by corrosion or deposition. TABLE. Weight per Foot of Wrought-Iron Tubing For Gas, Water, and Steam. GAB. WATEK. STEAM. Internal Diameter. Weight per Foot. Internal Diameter. Weight per Foot. Internal Diameter. Weight per Foot. Inches. Lbs. Ozs. Inches. Lbs. Ozs. Inches. Lba. Ozs. i 14J i 15 i 15i i 1 5ft i 1 7J i 1 8 i 1 15 1 2 1 1 2 3| U 2 10 li 2 14 11 3 4* li 3 2J li 3 9 14 4 2 4 6J 2 4 14 2 5 8 2* 5 10i 2* 6 4 2i 7 Uniformity in the screws or threads of service pipes and fittings is greatly to be desired, a large proportion of the leakage being due to the want of this. The screwed joint may be too slack, in 294 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS TABLE. Weight of Wronght-Iron Gas Titles and Fittings. Tubes. Fittings. Internal Diameter Inches. Weight per 100 feet. Weight per 1000 feet. Weight of 10 Elbows. Weight of 10 Tees. Weight of 10 Crosses. Cwts. Qrs. Lbs. Tons. Cwts. Qrs. Lbs. Lbs. Ozs. Lbs. Ozs. Lbs. Ozs. i 010 0220 1 1 1 1 8 i 1 14 0330 1 7 1 8 1 14 i 026 524 1 13 2 4 2 3 8 6J 8 9J 2 15 3 3 4 i 1 22J 12 1 4 6 6 4 6 11 i 1 2 26 17 1 8 6 4 7 10 9 2 ii 2 1 11 1 3 1 26 10 10 12 15 14 11 Ii 287 1 8 14 15 8 16 7 18 10 if 8 12 1 11 8 15 12 20 21 4 2 8 3 21 1 19 1 14 22 6 27 31 4 2i 4 26 2218 30 2 32 8 41 4 2i 606 2 10 1 22 46 2 50 16 51 4 2J 6 1 19 2 14 22 55 10 68 8 80 10 8 6 20 3134 73 8 85 5 88 12 Si 7 1 14 8 13 3 101 121 129 4 820 4600 126 L44 158 TABLE. Pitch of the Whitworth Taps and Dies Jor Gas Tubing. Internal External Number of Internal External < Number of Diameter of Diameter of Threads per Diameter of Diameter of Threads per Pipe. Pipe. Inch. Pipe. Pipe. Inch. 0-385 28 2 2'347 ii 0-520 19 2l 2-467 ii 0-665 19 2i 2-587 II 0-882 14 2f 2-794 ii 034 14 2\ 3-001 ii i 302 II 2f 3-124 ii i- 492 II 2f 3'247 ii I; '650 II 2& 3-367 IT I; '745 ii 3 3'485 ii I 882 ii si 3-698 ii Ij 021 II 3^ 3-912 ii I; 2-047 II 3f 4'i25 ii I] 2-245 II 4 4'339 ii SERVICE PIPES AND FITTINGS 295 which case leakage often follows ; on the other hand, when a socket is too small to receive the screwed end of a pipe, instead of running the tap into the one, or the dies over the other, careless workmen are often content to let the joint pass, provided they can succeed in getting a single thread to bite. The natural settlement 296 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS of the ground, the traffic over the surface, or the first keen frost, disjoints the connection, and an escape follows. PRICE LIST OF WROUGHT- No. 1 2 3 4 5 G INTERNAL DIAMETER. INCHES. Tubes, 2 to 14 feet long, per foot Pieces, 12 to 23i inches long, each Do. 3 to Hi Longscrews, 12 to 23 J ,, 3 to Hi 13ends i s. d. 2 4 2 5 4 5i i s. d. 2i 5 3 7 5 6i I s. d. 3 7 4 9 6 7 i s. d. 41 9 6 11 8 8 f s. d. 6 1 8 1 2 10 11 1 s. d. 8& 1 4 11 1 6 1 1 3 789 Springs, not Socketed . . 4 5 6 7 9 11 10 11 12 18 14 15 Socket Union (10), Pipe Do. (11) Elbows, Wrought-Iron . . . Tees ... Crosses ... Plain Sockets o"e 6 10 H 2 6} 6i 1 I 1 2 6 7 7 1 2 3 8 9 1 5 3 U o 4 10 1 1 9 3 5 6 1 2 1 3 2 3 4 1.6 17 Diminished Sockets .... Flanges . ... o'*8 3 9 4 10 5 1 6 1 2 6 7 1 4 18 19 20 21 22 Caps (18), Plugs (19) .... Baoknuts (20), Nipples (21) . . Union Bends . 2 1 3 2 2 6 3 2 3 4 3 3 9 5 3i 5 6 4 6 3 23 Hound Elbows, Wrought-Iron . 7 7 8 9 1 1 4 24 2 3 2 3 2 9 3 6 4 6 6 6 25 26 27 28 29 Do. with Brass Plugs Bound Way Iron Cocks . . . Do. with Brass Plugs Cock Spanners, Wrought-Iron . Do. Malleable Cast-iron 4 6 3 6 5 1 7 5 6 4 6 6 1 4 8 7 6 5 6 9 1 8 10 10 6 7 6 13 2 1 2 30 31 32 33 34 Syphon Boxes, 1 Quart . . . Do. 2 ... Do. 3 ... Do. 4 ... Malleable Cast Round Elbows . o"e O"6i 0*7 11 "S 12 16 20 21 10 13 17 22 23 i ,1 (35) Tongs or Nippers, (36) Stocks, Dies, and Taps, at prices as quoted by the manufacturer. If tubes are required to be of longer length than 14 ft., they are charged at the next higher rate. Tubes of intermediate diameters charged at the price of the next larger size. SERVICE PIPES AND FITTINGS 297 IRON TUBING AND FITTINGS, ETC. li j i* If 2 *i 21 2| 3 i 4 s. d. s. d. a. d. s. d. s. d. s. d. s. d. a. d. s. d. s. d. 11 1 2 1 6 1 9 2 7 3 3 4 4 6 5 6 7 1 8 2 2 6 3 4 6 6 3 7 G 9 11 6 14 6 1 1 1 4 2 2 3 4 4 9 6 7 8 9 2 2 G 3 3 4 5 6 7 8 6 10 12 6 15 6 1 3 2 2 6 3 4 6 5 6 6 6 7 6 8 6 10 1 9 2 3 3 3 4 3 6 6 10 12 16 25 32 6 1 4 1 8 2 6 3 3 5 6 7 6 10 12 19 26 6 9 8 9 10 12 14 JO 18 22 28 1 9 2 3 3 3 6 5 6 8 6 11 14 22 28 1 9 2 6 3 3 9 6 9 6 12 6 16 6 24 30 3 3 6 4 6 5 3 10 6 16 21 30 42 50 6 7 9 1 1 6 2 6 3 3 6 5 6 9 11 1 1 1 3 2 3 4 5 7 9 1 6 1 9 2 2 6 3 9 5 6 9 8 6 10 11 6 8 10 1 1 3 2 2 6 3 6 4 9 7 10 6 8 10 1 1 9 2 3 3 3 6 4 6 5 6 8 6 10 11 6 13 6 16 19 22 25 30 36 1 11 2 6 3 4 3 10 6 6 10 13 16 25 32 8 6 11 1* 18 27 36 44 50 75 90 15 19 6 2-5 32 47 GO 90 110 140 190 10 13 17 6 22 38 54 62 70 100 160 19 28 36 42 GO 85 105 120 180 280 2 4 3 3 6 4 4 9 6 7 6 9 12 14 1 8 2 2 2 9 3 3 4 9 6 7 6 9 12 14 14 15 15 6 16 18 18 19 21 23 25 30**0 35"0 40"0 . . . . 24 25 26 6 28 32 35 40 45 50 56 25 27 29 31 34 38 42 47 54 60 1 9 2 3 3 3 6 5 6 9 12 15 30 40 Springs ; if socketed, sockets added at list prices. Gas tubes and fittings, per cent. Discount n Galvanized Steam and water Galvanized Iron Cocks over 2 in. at special discounts. 298 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS HIGH PRESSURE DISTRIBUTION. The distribution of gas at a higher pressure than was formerly required has become essential. The necessity for higher pressures, due chiefly to the general adoption of the incandescent burner, has led to the boosting up of the pressure beyond what is usually given by the gasholders. An increase in the consumption of gas, inadequate delivering capacities of existing mains, and the centralization of manufacturing works, are also amongst the factors that have brought into prominence the question of the best means of economically dis- tributing gas under the new conditions. Generally speaking, a shortage of pressure is found in outlying districts, due to the restricted size of the mains, and also to the trunk mains from which the smaller mains take their supply, being over- taxed by the consumption en route. High pressure distribution offers a solution, other than increasing the size of the mains generally, for many of the difficulties connected with inadequate pressure, but at the same time it is not a system that should be adopted indiscriminately. A special study of the prevailing conditions of supply is necessary, and whether the existing mains could be utilized, or whether new mains would have to be laid. The ideal conditions for high pressure distribution may be summarized as follows : (i) The supply of gas to a district where the pressure in the existing mains is inadequate ; (2) supplying gas from the works to outlying gasholders, and (3) reinforcing the pressure in trunk mains. But in order to obtain the full advantage of the system, without any attendant disadvantages, care must be taken to see that the jointing of the old mains, and the attachment of the service pipes thereto, are in perfect condition, and if they are not so, to put them in such condition. Any neglect in these respects will inevitably result in an increase in the loss by leakage. In all cases, excepting where gas is supplied to gasholders, it is necessary to employ district governors to regulate the supply from the high to the low pressure main ; or a service pipe may be taken direct from the high pressure main, and a service governor applied to reduce the pressure to suit requirements of consumers on the route of the high pressure main. HIGH PRESSURE DISTRIBUTION 299 Compression of the gas is best obtained by means of blowers, reciprocating compressors, or rotary exhausters of modified design. Various firms make a speciality of compressors of these types. The Bryan Donkin Co. , Ltd., have introduced a rotary compressor (Fig. 156) which retains the advantages of the exhauster, though specially designed for high pressure work. The compressor is made both in the single and double stage according to the pressure required, and may be driven by steam, gas engine, or electric motor. The main difference in design from their ordinary exhauster is that the central block, which ordinarily serves to guide the FIG. 156. motion of the slide, is mounted on a revolving steel shaft, which acts as the driving member of the machine. The cast-iron drum, which in the exhauster drives the slides round, in the case of the compressor is driven round by the slides which constitute the pistons of the machine. A simple arrangement of plant (Fig. 157), where only a moderate increase of pressure is required, is made by the same firm. It consists of a small pressure blower driven by a gas or steam engine, which raises the pressure in the distributing mains that are directly connected to the outlet of the compressor. A district governor is fixed on the outlet main which regulates 300 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS the pressure maintained on the district. The arrangement can be controlled from the works. A compressor of the same type can be utilized for fixing at some point in the district to meet the conditions of an over-taxed trunk main that is supplying mains of a smaller diameter. The compressor draws the gas from the trunk main and raises the pressure before dis- tributing the gas to the smaller mains. This type of pressure-raising plant is suitable for pressures up to 36 in. George Waller & Son are makers of three types of pres- sure-raising plant namely, (i) high speed high pressure boost- ing fans for raising the pressure throughout a district, and for dealing with large volumes at comparatively light pressures ; (2) rotary compressor, three or four blade types, built on the lines of their exhausters (Figs. 70 and 71) and modified to work against pressures up to 7 Ibs. per square inch ; (3) FIG. 157. reciprocating double-acting compressors for high pressure trans- mission from 7 Ibs. up to 50 Ibs. per square inch. The reciprocating compressor may be belt-driven from gas engine, steam engine, or electric motor, or arranged tandem with steam cylinder direct acting, as may be most convenient. The rotary compressor of James Milne & Son (Fig. 158) is designed for pressures up to 3^ Ibs. per square inch ; the usual driving power being by means of a gas engine, though any other means of drive may be adopted. A steam driven reciprocating compressor, with automatic speed regulation controlled by the gas delivery pressure, is also made by them for delivery pressures of 5 Ibs. and upwards. The centrifugal type of booster made by the Sturtevant Engineering Co., and driven by their gearless steam turbine, is PUBLIC LIGHTING 301 also an efficient apparatus where only moderate pressures have to be dealt with. The machines are built in sizes having outputs ranging from 20,000 to 500,000 cub. ft. per hour, and are capable of raising the pressure from the normal up to 20 in. FIG. 158. A rotary type of machine is also made by them for pressures up to 2 or 3 Ibs. per square inch. PUBLIC LIGHTING. There are at present three systems applicable to the illumina- tion of public thoroughfares namely : (i) low pressure, (2) self- intensifying high power, and (3) high pressure. The height of a lamp pillar for low pressure lamps should not be less than 10 feet from the surface of the ground. For high pressure lighting the height of the pillar ranges from 14 feet upwards according to local circumstances. 302 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS A f-in. or even a J-in. lead pipe is not suitable for placing in the interior of a lamp column. In cold districts, in winter, the m FIG. 160. FIG. 161. condensed moisture in a pipe of this small bore becomes frozen, filling up the entire length with solid ice in a very short time. This PUBLIC LIGHTING 303 is probably due to the wavy irregularities in the pipe preventing the water from draining rapidly away. Galvanized wrought-iron pipe is best for lamp columns and for placing against a wall for the supply of a bracket lamp, and J in. is the smallest size that should be used. In situations exposed to cutting winds, and where the frost is keen, f-in. wrought-iron pipes are best. If the service pipe at the entrance of the base of a lamp column has not very ample fall to the main, the water of condensation, unable to drain quickly away, will inevitably be frozen at that point during frost, and, by accretion, will eventually interrupt the passage of the gas. It is not unusual to find one half the public lights in some districts extinguished at night when a severe frost prevails. This is simply due to mismanagement, as it would not occur if atten- tion were paid to the matters indicated above. The supply of gas to public lamps is usually fixed at 4 cub. ft. per hour. A regulator to each lamp secures the necessary supply FlG l6 of gas to which the burner is regulated. Borradaile's, Peebles', Wright's " Precision," and Simmance-Abady lamp governors are well known and efficient types of governors for this purpose. Various service and lamp clearers are to be had for the purpose of clearing out obstructions from services and fittings. Hutchinson Brothers' service cleanser (Fig. 162) is a handy instrument for this purpose. Satisfactory public lighting, as between gas companies and local authorities, is best secured by the adoption of a good average meter system, and the application of a governor to every lamp. FIG. 162. 304 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS The incandescent burner may be said to have revolutionized street lighting. Since Welsbach introduced his burner, continuous progress has been made, not only by the Welsbach Co., but by numerous other makers. The burners of the Welsbach Co., Wm. Sugg & Co., the Anti- vibration Incandescent Lighting Co., and Geo. Bray & Co., are typical of the low pressure class, both upright and inverted. Fig. 163 is an illustration of the Bray " 1907" S.L. burner. It is constructed of a tube having a series of fine slits instead of the usual wire gauze, through which the mixture of gas and air passes. The burners are made in shapes and sizes to suit all conditions. The upright incandescent bur- ner is being gradually superseded by the inverted form. The efficiency of the latter, due to the facilities for superheating the gas and air supply, is often as much as 40 candles per cub. ft. A further advantage is that a shadowless light is obtained, as there is no framework or gallery below the burner. Typical of the high power system are the lamps of the Welsbach Light Company, Wm. Sugg & Co., the " Graetzin," Moffat's, A. E. Podmore, the Bland Light Syndicate, and the New Inverted Incandescent Gas Lamp Co. The Welsbach lamp (Fig. 164) is made with steel or copper casing, and built in four sizes namely : 1500, 1000, 600, and 300 candle power. The first is of the four-burner, and the second and third of the three-burner class, whilst the last is constructed with one burner. The " 1912 " lamp (Fig. 160) of William Sugg & Co. is a good example of modern low pressure lighting. The burners are of the horizontal type, so arranged to superheat the mixture of gas and air. All the adjustments are outside the lamp and away FIG. 164. PUBLIC LIGHTING 305 from the heated products of combustion. An atmospheric flash- light burner is attached which lights the mantles ; its consumption is I cub. ft. of gas in 12 hours. The Bland lamp (Fig. 165) is constructed of copper and fitted with a Bland inverted burner. The gas supply is taken up one of the astragals to the top of the reflector, where the gas and air supplies are adjusted. A 3-light Bland street lamp is also made. FIG. 165. FIG. 166. Fig. 166 illustrates the one light circular lamp of the New Inverted Incandescent Gas Lamp Co. Two, three, and four- light lamps with burners to pass 3! to 4 cub. ft. per hour are also made. High Pressure Lighting. There can be no doubt that the present systems of high pressure lighting are a great advance on the low pressure. Whether the efficiency of 60 candles per cubic foot can be still further improved upon will depend on research. We believe it will. Amongst the systems in use in this country are the James Keith and Blackman Co., the Welsbach Light Co., Wm. Sugg & Co., the " Pintsch," " Graetzin," and the " Selas " of Bever and Wolff. All these necessitate some form of compressing plant to increase the pressure of the gas from the normal of say, 3 in. to a pressure of 54 ins., or higher if necessary, and also special mains, preferably of steel. 306 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS ^ i .r M *t ^3 o SS 5 3 til * OQ I. " 5? S I r i o j 'S I 6 a 3 l-s-g s5 1|| Sal a ! O o3 fig 3 O '-> Og, s -' O U to 1! ft^ I! of jo BJHOH jo jaqransj Suitung jo sjnojj jo UOI^.UIQ ifeaj^ pasting jo eunj; eSBjaAy ^ ^ O O O5 . .SSiS; .OOOS-<*G "^ CO O 00 CO t^ O Ol "^ CO o o to (MOorc (MOo ?O ^ r*i i UiCTi ( rHrHr-l j PUBLIC LIGHTING 307 O5 CC CO GO CO t^ o 35 OD H rH rH rH CM Michaelmas Quarter. Midsummer Quarter. Day ter. ady Q S3 % t-COlOTti^ i I CM CO ^* O <* SO CSJ CO C^ CO CO i 1 CM CO t O<-(C3 CO rH - 12 CONSUMERS' GAS METERS. Gas meters are either " wet " (Figs. 173 and 174) or " dry " -(Figs. 175 and 176). The wet meter has a measuring wheel or drum enclosed in an iron case charged with water up to a certain level, called the " water- line." The drum is divided into compartments similar to the FIG. 173. FIG. 174. station meter, and the measurement and indication, or registration, of the gas passing through it are performed in the same manner. The dry meter has usually a case of tinned-iron. This is divided into compartments by a central partition and two or more 3i6 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS movable diaphragms with prepared flexible leather sides. The gas enters and leaves these compartments alternately through valves whose passages are made to open and close at the proper moment. The alternate expansion and contraction of the inner FIG. 175. FIG. 176. and outer spaces (after the manner of the ordinary bellows), by the pressure of the gas exerted on the surfaces of the diaphragms, are communicated by levers and cranks to the wheelwork of the indicators, which are alike in both classes of meter. Meters as tested under the pro- visions of the " Sales of Gas Act, 1859," are stamped as correct by the inspector when their registration does not vary from the true standard measure of gas more than 2 per cent, in favour of the seller and 3 per cent, in favour of the consumer. Added together, the range is 5 per cent. " Compensating "meters were in- troduced to overcome the difficulty caused by the limitation in the range of the water-level of wet meters. Most of these have a reservoir of water within the case distinct from the water in which the measuring wheel revolves ; and various automatic expedients are adopted for transferring this water as long as it lasts, to the body of the meter, to compensate for the diminution of water therein by evaporation or otherwise. CONSUMERS' GAS METERS 317 The action of the Warner & Cowan measuring wheel (Fig. 177) is independent of the water-line ; the compensation in this instance being effected by a second and smaller wheel contained within, and revolving with, the larger one, but having its partitions arranged in the opposite direction. When a depression occurs in the water- line of a meter from any cause, a volume of gas in excess of the true quantity is passed ; but in this instance the excess in volume of the gas is returned by the small wheel to the meter inlet to be remeasured. The Sanders & Donovan meter (Fig. 178) is provided with a FIG. 178. compensating hollow float of metal plate, accurately balanced on pivots within the front portion of the case, and independent of the meter's action. As the water is added to or withdrawn, the float rises or sinks in proportion, and thus the correct level is maintained. When the drum or measuring wheel of a meter is driven at a speed exceeding 120 revolutions per hour (except two and three lights, when it may have a speed of 144), it absorbs an undue amount of the available gas pressure, and its registration is falsified. It is important, therefore, to see that all meters fixed are adequate to the supply of the greatest number of lights in use at one time on the premises of the consumer. Mr. Urquhart's " Reliance " meter and Mr. Hunt's meter, both of which are on the compensating principle, though different in character, are exceptions to the rule above stated, as they measure correctly even when the measuring wheel is caused to revolve at speeds in excess of the normal rate. This result is obtained by a reverse action, by which the gas enters through 3i8 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS passages in the valve chamber in the body of the meter, and thence into the drum, from which it makes its escape through the bent tube to the outlet. The inlet pressure thus bears upon nearly the whole surface of the contained water, and the measuring chambers are practically unaltered in capacity. It need scarcely be pointed out, however, that anything like a general resort to the practice of allowing the use of meters too small for the consumption except at extraordinary pressures, is a serious evil in various ways loss by leakage is increased ; the illuminating power of the gas is practically reduced ; and con- sumers whose meters and fittings are adequate, suffer by the prevailing high pressure. One-light meters, which formerly were extensively employed, are now altogether inadmissible ; and even two-light meters should only be sparingly used. The low price at which gas is sold encourages its extended consumption ; and the houses are becoming fewer in number every day where this small size is sufficient to afford an adequate supply, at reasonable pressures, to the number of lights in regular use. The regular periodical inspection of meters is a point of the utmost importance, and ought never to be neglected. The indices of wet meters in dwelling houses, etc., should be noted, and water supplied to the proper level wherever deficient, at least once every six weeks. The meters in mills, manufactories, and large estab- lishments of every kind where the consumption of gas is heavy, should be inspected for the like purpose once every fourteen days. The inspector should always be provided with a supply of leather washers for the different screws and plugs, to replace any that are worn out. Meters in cold and exposed positions should be protected by a suitable covering during frost, to prevent interruption to the supply of gas by the water becoming frozen. Woollen rags or wrappings of any kind will answer the purpose. Greenall.& Heaton's "Positive" meter (Fig. 179) differs in construction from those above described. The meter has two measuring cylinders, each divided into two separate chambers by a hollow cylindrical piston, sealed with glycerine within the annular space between the inner and outer parts of the cylinders. The chambers are connected by the gas-ways to the respective valve ports. The length of the stroke of the pistons is fixed and CONSUMERS' GAS METERS 319 definite, so that the displacement of gas at each stroke is the same and does not vary. One piston is set half a stroke in advance of the other, and thus each carries the other over the centre. The glycerine seal is not affected by the initial pressure, but only by the slight differential pressures above and below the pistons ; in other words, only the slight pressure which is required to actuate the meter. The motive power meter is but rarely required, but it is FIG. 179. FIG. 180. exceedingly useful in certain positions, where the pressure, from some unavoidable cause, is insufficient to afford an adequate supply of gas. In construction it is like an ordinary meter, but instead of the gas pressure being the motive power, the gas is exhausted from the main by the measuring wheel. This is set in motion by a descending weight, attached to which is a cord wound on a drum revolving in bearings on the top of the meter case, the drum being geared to the shaft of the measuring wheel, which projects through the back of the case. The speed of the meter, and consequently the pressure of gas obtained, are regulated by the weight aforementioned. Parkinson's motive power meter is shown in Fig. 1 80. The " prepayment " or " slot " meter, of which there are various forms, is an ingenious device for extending the sale of gas amongst small consumers. By the addition of a simple mechanism contained in a box attached to the ordinary wet or dry meter, and 320 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS on dropping a penny through a slot therein, a quantity of gas of the value of the penny is allowed to pass to the burner. When the gas thus paid for is consumed, the supply ceases until another prepayment is made. By another arrangement, on prepayment of a given sum say 4^. for i-oo cub. ft. an extra dial on the meter is set to pass the quantity of gas ; and when this is consumed a valve shuts off the supply, unless, in the meantime, a further payment has been made, and the dial is reset. For the sizes of meters and their measuring capacity, see under Internal Fittings. Board of Trade : Standards Department. Actual Sizes in Inches and Parts of an Inch of Standard Gas Meter Union Gauges,, igoi. Denomination. No. qf Lights. ; Inches. 80-100 3-018 60 2-448 50 2-250 30 2-052 20 1-820 10 i '451 5 ri5,3 3 0-986 ; Depth of Thread. Pitch. r Inch. " 0-057 ii 0-057 ii 0-057 ii 0-058 ii 0-057 ii 0-057 ii 0-055 12 0-036 18 The pitch varies 0*002 and 0*003 inch. Dimensions of Inside of Screw-Plug. No. of Lights. Inches. No. of Lights. Inches. 80-100 2-31 20 1-41 60 2"OI 10 i -06 50 1-76 5 0-82 30 1-56 3 0-67 o'ooi inch. NOTE. The above sizes are the actual, measurements of the minimum diameter of " boss " opening to admit " short shank of lining." CONSUMERS' GAS METERS 321 Variations in the dimensions of unions for equal-sized meters are a source of expense in the case of changing from one make to another. The Board of Trade in 1901 suggested that the unions of gas meters throughout the trade should be made of uniform size, and the preceding table gives the dimensions * and other particulars proposed. Testing Meters. For the verification of gas meters by a public inspector under the " Sales of Gas Act," a somewhat elaborate set of apparatus is required. For ordinary use in testing meters in a gas-works, the following may be provided (Fig. 181) : A standard gasholder of 10 cub. ft. capacity ; a proving bench ; an overhead water cistern ; a float of lights ; and thermometers for taking the temperature of the air and water. FIG. 181. In testing, it is important to secure uniformity in the temperature of the air or gas in the test holder, the water in the tank, and the air in the room, viz. 60 Fahr. ; otherwise corrections for varying temperatures have to be made. y ri 322 NEWBIGGING'S HANDBOOK. FOR GAS ENGINEERS Place the meter to be tested on the proving bench, charge it with water to the proper water-line (if a wet meter) , and connect it with the holder and to the float of lights (if gas is being used). See that the pointer of the small metal drum above the index in the wet meter, or of the small circle on the index plate of the dry meter, coincides with one of the figures marked thereon. If it does not, pass a small quantity of gas through till the necessary adjust- ment is effected. Next, fill up the test holder till the zero line of the scale upon it is exactly opposite its pointer. This being done, turn the gas or air on to the meter, and allow the meter to work till the small metal drum has made one or more revolutions, taking care to close the stop-cock when the pointer of the drum is exactly over the figure from which the start was made. The meter registration is then compared with that of the holder scale. If they correspond, the meter is exactly correct ; but if the scale on the holder indicates less or more than the small drum on the meter, the percentage of error is calculated ; or it can be ascertained on reference to the tables on the following pages. [TABLES. CONSUMERS' GAS METERS 323 TABLES. Showing the Percentage of Error in Meters according as their Registration differs from the Indications of the Test Gasholder. The sign + is used to indicate fast, and to indicate slow. Meters not exceeding 2 per cent, fast, or 3 per cent, slow, are correct within the meaning of the " Sales of Gas Act." Meter Eegistering 1 Foot. Meter Eegistering 2 Feet. Meter Eegistering 3 Feet. Meter Eegistering 3 Feet. Beading of Scale of Gas- holder. Amount of Error. Reading of Scale of Gas- holder. Amount of Error. Beading of Scale of Gas- holder. Amount of Error. Beading of Scale of Gas- holder. Amount of Error. Foot. Per Cent. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. 0-90 + 11-11 1-80 + 11-11 2-70 -f 11-11 3-10 - 3-22 91 + 9-89 81 + 10-50 71 + 10-70 11 - 3-54 92 + 8-70 82 + 9-89 72 + 10-30 12 - 3'85 93 + 7-25 83 + 9-29 73 + 9-89 13 - 4-16 94 + 6-36 84 + 8-70 74 + 9-49 14 - 4-46 95 + 5-26 85 + 8-11 75 + 9-09 15 - 4-76 96 + 4-17 86 + 7-63 76 + 8-70 16 - 5-06 97 + 3-09 87 + 6-95 77 + 8-31 17 - 5-36 98 + 2-04 88 + 6-38 78 + 7-92 18 - 5-66 99 + 1-01 89 + 5-82 79 + 7-53 19 - 5-85 1-00 Nil. 1-90 H- 5-26 2'80 + 7-14 3-20 - 6-25 01 - i-oo 91 + 4-71 81 + 6-76 21 - 6'64 02 - 1-97 92 + 4-17 82 + 6-38 22 - 6-82 03 - 2-82 93 + 3-63 83 + 6-01 23 - 7-12 04 - 3-85 94 -f- 3-09 84 + 6-63 24 - 7-41 05 - 4-74 95 + 2-56 85 + 5-26 25 - 7-70 06 - 5-66 96 + 2-04 86 + 4-89 26 - 7-98 07 - 6-54 97 + 1-52 87 + 4-53 27 - 8-26 98 - 7-40 98 + I'Ol 88 + 4-17 28 - 8-54 09 - 8-26 99 + 0-50 89 + 3-81 29 - 8-82 1-10 - 9-10 2-00 Nil. 2'90 + 3-45 3-30 - 9-09 11 - 9-91 01 - 0-50 91 + 3-09 31 - 9-36 12 - 10-07 02 - 0-99 92 -f 2-74 32 - 9-64 03 - 1-48 93 + 2-39 33 - 9-91 04 - 1-96 94 + 2-04 34 - 10-18 05 - 2-44 95 + 1-69 06 - 2-91 96 + 1*35 07 - 3-38 97 + 1-01 08 - 3-85 98 + 0-67 09 - 4-31 99 + 0-33 2-10 - 4-76 3-00 Nil. 11 - 5-21 01 - 0-33 12 - 5-66 02 - 0-66 13 - 6-10 03 - 0-99 14 - 6-54 04 - 1-32 15 - 6-98 05 - 1'64 16 - 7-41 06 - 1-96 17 - 7-83 07 - 2-28 18 - 8-26 08 - 2-60 19 - 8-68 09 - 2-91 Y 2 324 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Meter Eegistering 5 Feet. Meter Registering 5 Feet. Meter Registering 5 Feet. Meter Eegistering 10 Feet. Beading of Scale of Gas- holder. Amount of Error. Reading of Scale of Gas- holder. Amount of Error. Reading of Scale of Gas- holder. Amount of Error. Reading of Scale of Gas- holder. Amount of Error. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. 4-50 + ll'll 5-02 - 0-40 5-54 - 9-75 9-00 + ll'll 51 + 10-86 03 - 0-60 55 - 9-91 01 + 10-99 52 + 10-62 04 - 0-79 56 - 10-07 02 + 10-86 53 + 10-38 05 - 0-99 57 - 10-23 03 + 10-74 54 + 10-13 06 - 1-19 58 - 10-39 04 + 10*62 55 + 9-89 07 - 1-38 59 - 10-55 05 + 10-50 56 + 9-65 08 - 1-57 5-60 - 10-71 06 + 10-38 57 + 9-41 09 - 1-77 61 - 10-87 07 + 10-25 68 + 9-17 5-10 - 1-96 62 - 11-03 08 + 10-13 59 + 8-93 11 - 2-15 63 - 11-19 09 + 10-01 4-60 + 8-70 12 - 2-34 9-10 + 9-89 61 + 8-46 13 - 2-53 11 + 9-77 62 + 8-23 14 - 2-72 12 + 9'65 63 + 7-99 15 - 2-91 13 + 9-53 64 + 7-76 16 - 3-10 14 + 9'41 65 + 7-53 17 - 3-29 15 + 9-29 66 + 7-30 18 - 3-47 16 + 9-17 67 + 7-07 19 - 3-66 17 + 9-05 68 -f 6-84 5-20 - 3-85 18 + 8-93 69 + 6-61 21 - 4-03 19 + 8-81 4-70 + 6-38 22 - 4-21 9-20 + 8-70 71 + 6-16 23 - 4-40 21 + 8-58 72 + 5-93 24 - 4-58 22 4- 8-46 73 + 5-71 25 - 4-76 23 + 8-34 74 + 5-49 26 - 4-94 24 + 8-23 75 + 5-26 27 - 5-12 25 + 8-11 76 + 5-04 28 - 5-30 i 26 + 7'99 77 + 4-82 29 - 5-48 27 + 7-87 78 + 4-60 5-30 - 5-66 28 + 7-76 79 + 4-38 31 - 5'84 29 -f 7-64 4-80 + 4-17 32 - 6-02 9-30 + 7-53 81 + 3-95 33 - 6-19 31 + 7-41 82 + 3-73 34 - 6-37 32 + 7'30 83 + 3-52 35 - 6'54 33 + 7-18 84 + 3-31 36 - 6-72 34 + 7-07 85 + 3-09 37 - 6-89 35 -j- 6-95 86 + 2-88 38 - 7-06 36 + 6-84 87 + 2-67 39 - 7-24 37 + 6-72 88 + 2-46 5'40 - 7-41 38 + 6'61 89 + 2-25 41 - 7-58 39 + 6-50 4-90 + 2-04 42 - 7-75 9-40 + 6-38 91 + 1-83 43 - 7-92 41 + 6-27 92 + 1-63 44 - 8-09 42 -|- 6'16 93 +- 1-42 45 - 8-26 43 + 6-04 94 + 1-21 46 - 8-42 44 + 5-93 95 f- 1-01 47 - 8-59 45 + 5-82 96 + 0'8l 48 - 8-76 46 + 5-71 97 + 0-60 49 - 8-93 ^ -47 + 5-60 98 + 0-40 5-50 - 9-09 48 -f 5-49 99 + 0-20 51 - 9-26 49 -f 5-37 5-00 Nil. 52 - 9-42 9-50 4- 5-26 01 - 0-20 53 - 9-59 51 i 4- 5-15 CONSUMERS' GAS METERS 325 Meter Registering 10 tfeet. Meter Registering 10 Feet. Meter Registering 10 Feet. Meter Registering 10 Feet. Reading of Scale of Gas- holder. Amount of Error. Reading of Scale of Gas- holder. Amount of Error. Reading of Scale of Gas- holder. Amount of Error. Reading of Scale of Gas- holder. Amount of Error. Feet. Per Cent.. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. 9-52 + 5-04 10-04 - 0-40 10-56 - 5'30 11-03 - 9'75 53 + 4-93 I 05 - 0-50 57 - 5-39 09 - 9-83 54 + 4-82 06 - 0'60 58 - 5-48 11-10 - 9-91 55 + 4-71 07 - 0-70 59 - 5-57 11 - 9-99 56 + 4-60 08 - 0-79 10-60 - 5-66 12 - 10-07 57 + 4-49 09 - 0-89 61 - 5-75 13 - 10-15 58 + 4-38 10-10 - 0-99 62 - 5-84 14 - 10-23 59 + 4-28 11 - 1-09 63 - 5-93 15 - 10-31 9-60 + 4-17 -12 - 1-19 64 - 6-02 16 - 10-39 61 + 4-06 13 - 1-28 65 - 6-10 17 - 10-47 62 + 3-95 14 - 1-38 66 - 6-19 18 - 10-55 63 + 3-84 15 - 1-48 67 - 6-28 19 - 10-63 64 + 3-73 16 - 1-57 68 - 6-37 11-20 - 10-71 65 + 3-63 17 - 1-67 69 - 6-45 21 - 10-79 66 + 3-52 18 - 1-77 10-70 - 6-54 22 - 10-87 67 + 3-41 19 - 1-86 71 - 6'63 23 - 10-95 68 + 3-31 10-20 - 1-96 72 - 6-72 24 - 11-03 69 -|- 3-20 21 - 2-06 73 - 6-80 25 - 11-11 9-70 + 3-09 22 - 2-15 74 - 6-89 71 + 2-99 23 - 2-25 75 - 6-98 72 + 2-88 24 - 2-34 76 - 7-06 73 + 2-77 25 - 2-44 77 - 7-15 74 + 2-67 26 - 2-53 78 - 7-24 75 + 2-56 27 - 2-63 79 - 7-32 76 + 2-46 28 - 2-72 10-80 - 7-41 77 + 2-35 29 - 2'82 81 - 7-49 78 + 2-25 10-30 - 2-91 82 - 7-58 79 + 2-15 31 - 3-01 83 - 7-66 9-80 + 2-04 32 - 3-10 84 - 7-75 81 + 1-94 33 - 3-19 85 - 7-83 82 + -83 34 - 3-29 86 - 7-92 83 + '73 35 - 3-38 87 - 8-00 84 + -63 36 - 3-47 88 - 8-09 85 + -52 37 - 3-57 89 - 8-17 86 + -42 38 - 3-66 10-90 - 8-26 87 + -32 39 - 3-75 91 - 8-34 88 + -21 10-40 - 3'85 92 - 8-42 89 + -11 41 - 3-94 -93 - 8-51 9-90 + -01 42 - 4-03 94 - 8-59 91 + 0-91 43 - 4-12 95 - 8-68 92 + 0-81 44 - 4-21 96 - 8-76 93 + 0-70 45 - 4-31 97 - 8-84 94 + 0'60 46 - 4-40 98 - 8-93 95 + 0-50 47 - 4-49 99 - 9-01 96 + 0-40 48 - 4-58 11-00 - 9-09 97 + 0-30 49 - 4-67 01 - 9-18 98 + 0-20 10-50 - 4-76 02 - 9-26 99 + o-io 51 - 4-85 03 - 9-34 10-00 Nil. 52 - 4-94 04 - 9-42 01 - o-io 53 - 5-03 05 - 9-51 02 - 0-20 54 - 5-12 06 - 9-59 03 - 0-30 55 - 5-21 07 - 9-67 326 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Meter Begistering 20 Feet. Meter Begistering 20 Feet. Meter Begistering 20 Feet. Meter Begistering 20 Feet. Reading of Scale Amount _f Beading of Scale Amount f\f Reading of Scale Amount _ t Reading of Scale Amount of Gas- holder. OI Error. of Gas- holder. OI Error. of Gas- holder. Of Error. of Gas- holder. of Error. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. 18-00 + 11-11 18-52 4- 7-99 19-04 + 5-04 19-56 + 2-25 01 + 11-05 63 + 7-93 05 4- 4-98 67 + 2-20 02 + 10-99 64 + 7-87 06 + 4-93 68 + 2-15 03 + 10-92 65 + 7-82 07 + 4-87 59 4- 2-09 04 + 10-86 66 + 7-76 08 + 4-82 19-60 + 2-04 05 + 10-80 67 4- 7-70 09 + 4-76 61 + 1-99 06 + 10-74 58 4- 7-64 19-10 + 4-71 62 + 1-94 07 + 10-68 69 + 7-59 11 + 4-65 63 4- 1-88 08 + 10-62 18-60 4- 7-53 12 + 4-60 64 + 1-83 09 + 10-66 61 + 7'47 13 + 4-'54 65 4- 1-78 18-10 + 10-50 62 + 7-41 14 + 4-49 66 4- 1-73 11 + 10-44 63 + 7-36 15 + 4-43 67 4- 1-68 12 + 10-38 64 4- 7-30 16 + 4-38 68 + 1-63 13 + 10-31 65 + 7-24 17 + 4-33 69 + 1-57 14 + 10-25 66 + 7-18 18 4- 4-28 19-70 + 1-52 15 + 10-19 67 + 7-13 19 + 4-22 71 + 1-47 16 + 10-13 68 + 7-07 19-20 + 4-17 72 4- 1-42 17 + 10-07 69 + 7-01 21 + 4-11 73 + 1'37 18 + 10-01 18'70 + 6-95 22 + 4-06 74 + 1-32 19 + 9-95 71 + 6-90 23 + 4-00 75 + 1'26 18-20 + 9-89 72 + 6-84 24 + 3-95 76 4- 1-21 21 + 9-83 73 + 6-78 25 + 3-89 77 4- 1'16 22 + 9-77 74 + 6-72 26 4- 3-84 78 4- 1-11 23 + 9-71 76 + 6-66 27 4- 3-78 79 + 1-06 24 + 9-65 76 + 6-61 28 + 3-73 19-80 4- 1-01 25 + 9-69 77 + 6-55 29 4- 3-68 81 + 0-96 26 + 9-58 78 + 6-50 19-30 + 3-63 82 + 0-91 27 + 9-47 79 4- G-44 31 + 3-57 83 + 0-86 28 + 9'41 18-80 4- 6-38 32 + 3-52 84 + 0-81 29 + 9-35 81 4- 6-82 33 4- 3-46 85 4- 0-75 18-80 + 9-29 82 + 6-27 84 + 3-41 86 + 0-70 81 4- 9-23 83 + 6-21 35 + 3-36 87 + 0'65 32 + 9-17 84 + 6-16 36 + 8-31 88 + 0-60 33 4- 9-11 85 + 6-10 37 + 8-25 89 -1- 0-55 34 + 9-05 86 4- 6-04 38 + 3-20 19'90 + 0-50 35 + 8-99 87 4- 5-98 89 4- 3-14 91 + 0-45 36 + 8-93 88 4- 5-93 19-40 + 3-09 92 + 0-40 37 + 8'87 89 + 6-87 41 + 8-04 93 + 0-35 38 -f 8-81 18-90 + 6-82 42 + 2-99 94 + 0-30 89 + 8-76 91 + 6'76 43 + 2-93 95 + 0-25 18-40 + 8-70 92 + 6-71 44 4- 2-88 96 + 0-20 41 + 8-64 93 + 6'65 45 + 2-82 97 + 0-15 42 + 8'68 94 + 5-60 46 + 2-77 98 + o-io 43 4- 8-62 95 + 6-54 47 + 2-72 99 + O'Oo 44 4- 8-46 96 + C-49 48 + 2-67 20-00 Nil. 45 + 8-40 97 + 6-43 49 4- 2-61 02 - o-io 46 + 8-34 98 + 5-37 19-50 + 2-56 04 - 0-20 47 + 8-29 99 + 5-31 51 + 2-51 06 - 0-30 48 4- 8-23 19-00 + 5'26 52 + 2-46 08 - 0-40 49 + 8-17 01 + 5-20 53 + 2-40 20-10 - 0-50 18-60 + 8-11 02 4- 5-15 64 4- 2-35 12 - 0-60 61 + 8-06 03 4- 6-09 66 + 2-30 14 - 0-70 CONSUMERS' GAS METERS 327 Meter Registering 20 Feet. Meter Eegistering 20 Feet. Meter Registering 20 Feet. Meter Registering 30 Feet. Reading of Scale of Gas- holder. Amount of Error. heading of Scale of Gas- holder. Amount of Error. Reading of Scale of Gas- holder. Amount of Error. leading of Scale of Gas- holder. Amount of Error. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. 20-16 - 0-79 21-20 - 5-66 22-24 - 10-07 27-00 + 11-11 18 - 0-89 22 - 5-75 26 - 10-15 02 + 11-03 20-20 - 0-99 24 - 5-84 28 - 10-23 04 + 10-95 22 - 1-09 26 - 6-93 22-30 - 10-31 06 + 10-86 .24 - 1-19 28 - 6-02 32 - 10-39 08 + 10-78 26 - 1-28 21-30 - 6-10 34 - 10-47 27'10 + 10-70 28 - 1-38 32 - 6-19 36 : - 10-55 12 + 10-62 20-30 - 1-48 34 - 6-28 38 ! - 10-63 14 + 10-54 32 - 1-57 36 - 6'37 22-40 ; - 10-71 16 + 10-46 34 - 1-67 38 - 6-46 42 - 10-79 18 + 10-38 36 - 1-77 21-40 - 6-54 44 - 10-87 27-20 + 10-30 38 - 1-86 42 - 6-63 46 - 10-95 22 + 10-21 20-40 - 1-96 44 - 6'72 48 - 11-03 24 + 10-13 42 - 2-06 46 - 6'80 22-50 - ll'll 26 + 10-05 44 - 2-15 48 - 6-89 28 + 9-97 46 - 2-25 21-50 _ 6-98 27-30 + 9-89 48 - 2-34 52 - 7-06 32 + 9-81 20-50 - 2-44 54 - 7-15 34 + 9-73 52 - 2-53 56 - 7-24 36 + 9-65 54 - 2-63 58 - 7-32 38 + 9-57 56 - 2'73 21-60 - 7-41 27-40 + 9-49 58 - 2-82 62 - 7'49 42 + 9-41 20-60 - 2-91 64 - 7-58 44 + 9-33 62 - 3-01 66 - 7-66 46 + 9-25 64 - 3-10 68 - 7-75 48 + 9-17 66 - 3-19 21-70 - 7-83 27-50 + 9-09 68 - 3-29 72 - 7-92 52 + 9-01 20-70 - 3-38 74 - 8-00 54 + 3-93 72 - 3-47 76 - 8-09 56 + 8-85 74 - 3-57 78 - 8-17 58 + 8-78 76 - 3-66 21-80 - 8-26 27-60 + 8-70 78 - 3-75 82 - 8-34 62 -f- 8-62 20-80 - 3-85 84 - 8'42 64 + 8-54 82 - 3-94 86 - 8'51 66 + 8-46 84 - 4-03 88 - 8-59 68 + 8-38 86 - 4-12 21-90 - 8-68 27-70 + 8-31 88 - 4-21 92 - 8-76 72 + 8-23 20-90 - 4-31 94 - 8-84 74 + 8-15 92 - 4-40 96 - 8-93 76 + 8-07 94 - 4-49 98 - 9-01 78 + 7-99 96 - 4-58 22-00 - 9-09 27-80 + 7-92 98 - 4-67 02 - 9-18 82 + 7-84 21-00 - 4-76 04 - 9-26 84 + 7-76 02 - 4-85 06 - 9-34 86 + 7-68 04 - 4-94 08 - 9-42 88 + 7'61 06 - 5-03 22-10 - 9-51 27-90 + 7'53 08 - 5-12 12 - 9-59 92 + 7-45 21-10 - 5-21 14 - 9-67 94 + 7-38 12 - 5-30 16 - 9-75 96 + 7-30 14 - 5-39 18 - 9-83 98 + 7-22 16 - 5-48 22-20 - 9-91 28-00 + 7'14 18 - 6-57 22 - 9-99 02 + 7-07 328 . NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Meter Eegistering 80 Feet. Meter Eegistering 80 Feet. Meter Eegistering 30 Feet, Meter Eegistering 80 Feet. Beading of Scale of Gas- holder. Amount of Error. Reading of Scale of Gas- holder. Amount of Error. Beading of Scale of Gas- holder. Amount of Error. Beading of Scale of Gas- holder. Amount of Error. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. 28-04 + 6-99 29-08 + 3-16 30-12 - 0-40 31-16 - 8-72 06 + 6-92 29-10 + 3-09 14 - 0-47 18 - 8-79 08 + 6-84 12 + 3-02 16 - 0-53 31-20 - 3-85 28-10 + 6-76 14 + 2-95 18 - 0-60 22 - 3-91 12 + 6-69 16 + 2-88 30-20 - 0-66 24 - 3-97 14 + 6-61 18 4- 2-81 -.22 - 0-73 26 - 4-03 16 + 6-53 29-20 + 2-74 24 - 0-79 28 - 4-09 18 + 6-46 22 + 2-67 26 - 0-86 31-30 - 4-16 28-20 + 6-38 24 + 2-60 28 - 0-92 32 - 4-22 22 + 6-31 66 + 2-53 30-30 - 0-99 34 - 4-28 24 + 6-23 28 + 2-46 32 - 1-06 36 - 4-34 26 + 6-16 29-30 + 2-39 34 - 1-12 38 - 4-40 28 + 6-08 32 + 2-32 36 - 1-19 31-40 - 4-46 28-30 + 6-01 84 + 2-25 38 - 1-26 42 - 4-52 32 + 5-93 36 + 2-18 80-40 - 1-32 44 - 4-58 34 + 5-86 38 + . 2-11 42 - 1-38 46 - 4-64 36 + 5-78 29-40 + 2-04 44 - 1-44 48 - 4-70 38 + 6-71 42 + 1-97 46 - 1-51 31-50 - 4-76 28-40 + 5-63 44 + 1-90 48 - 1-67 52 - 4-82 42 + 6-56 46 + 1-83 30-50 - 1-64 54 - 4-88 44 + 6-49 48 + 1-76 52 - 1-71 56 - 4-94 46 + 5-41 29-50 + 1-69 54 - 1-77 58 - 5-00 48 + 5-34 62 + 1-63 66 - 1-83 81-60 - 5-06 28*50 -I- 6-26 64 + 1-56 58 - 1-89 62 - 5'12 52 + 5-19 66 + 1-49 30-60 - 1-96 64 - 6-18 54 + 5-11 68 + 1-42 62 - 2-02 66 - 6-24 56 + 5-04 29-60 + 1-35 64 - 2-09 68 - 6-30 68 + 4-96 62 + 1-28 66 - 2-15 31-70 - 6-36 28-60 + 4-89 64 + 1-21 68 - 2-22 72 - 5-42 62 + 4-82 66 + 1-14 30-70 - 2-28 74 - 6-48 64 + 4-75 68 + 1-08 72 - 2-34 76 - 6-54 66 + 4-67 29-70 + 1-01 74 - 2-40 78 - 5-60 68 + 4-60 72 + 0-94 76 - 2-47 31-80 - 5-66 28-70 + 4-63 74 + 0-88 78 - 2-53 82 - 5-72 72 + 4-45 76 + 0-81 30-80 - 2-60 84 - 5-78 74 + 4-38 78 + 0-74 82 - 2-66 86 - 5-84 76 + 4-31 29-80 + 0-67 84 - 2-72 88 - 5-90 78 + 4-24 82 + 0-60 86 - 2-78 31-90 - 5-96 28-80 + 4-17 84 + 0-53 88 - 2-85 92 - 6-02 82 + 4-10 86 + 0-47 30-90 - 2-91 94 - 6-08 84 + 4-02 88 + 0-40 92 - 2-97 96 - 6-13 86 + 3-95 29-90 + 0-33 94 - 3-04 98 - 6-19 88 + 3-88 92 + 0-26 96 - 3-10 32-00 - 6-26 28-90 + 3-81 94 + 0-20 98 - 3-16 02 - 6-31 92 + 3-73 96 + 0-13 31-00 - 3-22 04 - 6-37 94 + 3-66 98 + 0-07 02 - 3-29 06 - 6-42 96 f 3-69 30-00 Nil. 04 - 3-35 08 - 6-48 98 + 3-52 02 - 0-07 06 - 3-42 32-10 - 6-54 29-00 + 3-45 04 - 0-13 08 - 3'48 12 - 6-60 02 + 3-38 06 - 0-20 31-10 - 8-54 14 - 8-66 04 + 3-31 08 - 0-27 12 - 2-60 16 - 6-72 06 + 3-24 80-10 - 0-33 u - 8-66 18 - 6-77 CONSUMERS' GAS METERS 329 Meter Registering 30 Feet. Meter Registering 30 Feet. Meter Registering 40 Feet. Meter Registering 40 Feet. Reading of Scale Amount nf Beading of Scale Amount nf Reading of Scale Amount nf Reading of Scale Amount _r of Gas- holder. OI Error. of Gas- holder. OI Error. of Gas- holder. OI Error. of Gas- holder. OI Error. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. 32-20 - 6-83 33-24 - 9-75 36-00 + 11-11 37-04 4- 7-99 22 - 6-89 28 - 9-81 02 4- 11-05 06 4- 7'93 24 - 6-95 28 - 9-86 04 + 10-99 08 4- 7-87 26 - 7-01 33-30 - 9-91 06 + 10-92 37-10 + 7-82 28 - 7-07 32 - 9-96 08 + 10-86 12 4- 7-76 32-30 - 7-12 34 - 10-01 36-10 + 10-80 14 4- 7-70 32 - 7-18 36 - 10-07 12 + 10-74 16 4- 7-64 34 - 7-24 38 - 10-12 14 4- 10-68 18 4- 7-59 36 - 7-30 33-40 - 10-18 16 + 10-62 37-20 4- 7-53 38 - 7-36 42 - 10-23 18 + 10-56 22 4- 7-47 32-40 - 7-41 44 - 10-28 36-20 + 10-0 24 4- 7-41 42 - 7-47 46 - 10-34 22 + 10-44 26 4- 7-36 44 - 7-53 48 - 10-39 24 + 10-38 28 4- 7-30 46 - 7-59 33-50 - 10-45 26 + 10-31 37-30 + 7-24 48 - 7-64 52 - 10-50 28 4- 10-25 32 4- 7-18 32-50 - 7-70 54 - 10-55 36-30 + 10-19 34 4- 7-13 62 - 7-76 66 - 10-61 32 + 10-13 36 4- 7-07 54 - 7-82 68 - 10-66 34 + 10-07 38 4- 7-01 56 - 7-87 33-60 - 10-71 36 4- 10-01 37-40 4- 6-95 58 - 7-93 62 - 10-76 38 4- 9-95 42 4- 6-90 32-60 - 7-98 64 - 10-82 36-40 + 9-89 44 4- 6-84 62 - 8-04 66 - 10-87 42 4- 9-83 46 4- 6-78 64 - 8-10 68 - 10-93 44 + 9-77 48 4- 6-72 66 - 8-15 33-70 - 10-98 46 4- 9-71 37-60 4- 6-66 68 - 8-21 72 - 11-03 .48 + 9-65 52 4- 6-61 32-70 - 8-26 74 - 11-09 36-50 + 9-59 54 4- 6-55 72 - 8-32 76 - 11-14 52 4- 9-53 56 4- 6-50 74 - 8-37 78 - 11-19 64 4- 9-47 58 4- 6-44 76 - 8-43 56 4- 9-41 37-60 4- 6-38 78 - 8-49 58 4- 9-35 62 + 6-32 32-80 - 8-54 36-60 + 9-29 64 4- 6-27 82 - 8-60 62 4- 9-23 66 4- 6-21 84 - 8-66 64 4- 9-17 68 4- 6-16 86 - 8-71 66 4- 9-11 37-70 4- 6-10 88 - 8-77 68 4- 9-05 72 4- 6-04 32-90 - 8-82 36-70 + 8-99 74 4- 5-98 92 - 8-87 72 4- 8-93 76 4- 5-93 94 - 8-93 74 4- 8-87 78 4- 5-87 96 - 8-99 76 + 8-81 37-30 4- 5-82 98 - 9-04 78 4- 8-76 82 4- 5-76 33-00 - 9-09 36-80 4- 8-70 84 4- 5-71 02 - 9-15 82 + 8-64 86 4- 6-66 04 - 9-20 84 4- 8-58 88 4- 5-60 06 - 9-26 86 + 8-52 37-90 4- 5-54 08 - 9-31 . ,. I 88 4- 8-46 92 + 5'49 33-10 - 9-36 36-90 + 8-40 94 4- 5-43 12 - 9-42 92 4- 8-34 96 4- 5-37 14 - 9-47 94 4- 8-29 98 4- 5-31 16 - 9'53 96 4- 8-23 38*00 4- 5-26 18 - 9-59 98 4- 8-17 1 02 + 6-20 33-20 - 9-64 37-00 + 8-11 1 04 4- 6-16 22 - 9-70 02 + 8-05 06 + 5-09 330 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Meter Eegistering 40 Feet. Meter Registering 40 Feet. Meter Eegistering 40 Feet. Meter Eegistering 40 Feet. Reading of Scale of Gas- holder. Amount of Error. Reading of Scale of Gas- holder. Amount of Error. Reading of Scale of Gas- holder. Amount of Error. Reading of Scale of Gas- holder. Amount of Error. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. 38-08 + 5-04 39-12 + 2-25 40-16 - 0-40 41-20 - 2-91 38-10 + 4-98 14 + 2-20 ]8 - 0-45 22 - 2-96 12 + 4-93 16 + 2-15 40-20 - 0-50 24 - 3-01 14 + 4-87 18 + 2-09 22 - 0-55 26 - 3-06 16 + 4-83 39-20 + 2-04 24 - 0-60 28 - 3-10 18 + 4-76 22 + 1-99 26 - 0-65 41-30 - 3-15 38-20 + 4-71 24 + 1-94 28 - 0-70 32 - 3-19 22 + 4-65 26 + 1-88 40-30 - 0-75 34 - 3-24 24 + 4-60 28 + 1-83 32 - 0-79 36 - 3-29 26 + 4-64 39-30 + 1-78 34 - 0-84 38 - 3-34 23 + 4-49 32 + 1-73 36 - 0-89 41-40 - 3-38 88-30 + 4-44 34 + 1-68 38 - 0-94 42 - 3-43 32 + 4-38 36 + 1-63 40-40 - 0-99 44 - 3-47 34 + 4.33 38 + 1-57 42 - 1-04 46 - 3-52 36 + 4-28 39-40 + 1-52 44 - 1-09 48 - 3-57 38 + 4-22 42 + 1-47 46 - 1-14 41-50 - 3-61 88-40 + 4-17 41 + 1-42 48 - 1-19 52 - 3-66 42 + 4-11 46 + 1-37 40-50 - 1-24 54 - 8-71 44 + 4-06 48 + 1-32 52 - 1-28 56 - 3-75 46 + 4-00 39-50 + 1-26 54 - 1-33 58 - 3-80 48 + 3-95 52 + 1-21 56 - 1-38 41-60 - 3-85 38-50 + 3-90 54 + 1-16 58 - 1-43 62 - 3-90 62 + 8-84 56 + 1-11 40-60 - 1-48 64 - 3-94 64 + 3-78 58 + 1-06 62 - 1-53 66 - 8-99 66 + 3-73 39-60 -f- 1-01 64 - 1-57 68 - 4-03 68 + 3-68 62 + 0-96 66 - 1-62 41-70 - 4-08 38-60 + 3-63 64 + 0-91 68 - 1-67 72 - 4-12 62 + 3-57 66 + 0-86 40-70 - 1-72 74 - 4-17 64 + 8-52 68 + 0-81 72 - 1-77 76 - 4-21 66 f 3-46 39-70 + 0-75 74 - 1-82 78 - 4-26 68 + 3-41 72 + 0-70 76 - 1-86 41-80 -- 4-31 38-70 + 3-36 74 + 0-65 78 - 1-91 82 - 4-36 72 + 3-31 76 + 0-60 40-80 - 1-96 84 - 4-40 74 + 3-25 78 + 0-55 82 - 2-01 86 - 4-45 76 + 3-20 39-80 + 0-50 84 - 2-06 88 - 4-49 78 + 3-14 82 + 0-45 86 - 2-10 41-90 - 4-54 38-80 + 3-09 84 + 0-40 88 - 2-15 92 - 4-58 82 + 3-04 86 + 0-35 40-90 - 2-20 94 - 4-63 84 + 2-99 88 + 0-30 92 - 2-25 96 - 4-67 86 + 2-93 39-90 + 0-25 94 - 2-30 98 - 4-72 88 + 2-88 92 + 0-20 96 - 2-34 42-00 - 4-76 38-90 + 2-82 94 + 0-15 98 - 2-39 02 - 4-81 92 + 2-77 96 + 0.10 41-00 - 2-44 04 - 4-85 94 + 2-72 98 + 0-05 02 - 2-49 . '06 - 4-90 96 + 2-67 40-00 Nil. 04 - 2-63 08 - 4-94 98 + 2-61 02 - 0-05 06 - 2-58 42-10 - 4-99 39-00 + 2-56 04 - o-io 08 - 2-63 12 - 5-03 02 + 2-51 06 - 0-15 41-10 - 2-68 14 - 5-08 04 + 2-46 08 - 0-20 12 - 2-72 16 - 6-12 06 + 2-40 40-10 - 0-25 14 - 2-78 18 - 5-17 08 + 2-35 12 - 0-30 16 - 2-82 42-20 - 6-21 39-10 + 2-30 14 - 0-35 18 - 2-87 22 - 5-26 CONSUMERS' GAS METERS 33i Meter Registering 40 Feet. Meter Eegistering 40 Feet. Meter Registering 40 Feet. Meter Registering 60 Feet. Reading of Scale of Gas- holder. Amount of Error. Beading of Scale of Gas- holder. Amount of Error. Beading of Scale of Gas- holder. Amount of Error. Beading of Scale of Gas- holder. Amount of Error. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. 42-24 - 6-30 43-28 - 7-58 44-32 - 9-75 45-00 + 11-11 26 - 5-35 43-30 - 7-62 34 - 9-79 02 + 11-06 28 - 5-39 32 - 7-66 36 - 9-83 04 + 11-01 42-30 - 5-44 34 - 7'71 38 - 9-87 06 + 10-96 32 - 5-48 36 - 7-75 44-40 - 9'91 08 + 10-91 34 - 5-53 38 - 7-79 42 - 9-95 45-10 + 10-86 36 - 5-57 43-40 - 7-83 44 - 9'99 12 + 10-81 38 - 6-62 42 - 7-88 46 - 10-03 14 + 10-76 42-40 - 5-66 44 - 7-92 48 - 10-07 16 + 10-72 42 - 5-71 46 - 7-96 44-50 - lO'll 18 + 10-67 44 - 6-75 48 - 8-00 52 - 10-15 45-20 + 10-62 46 - 5-80 43-50 - 8-05 64 - 10-19 22 + 10-67 48 - 5-84 62 - 8-09 56 - 10-23 24 + 10-52 42-50 - 5-88 54 - 8-13 68 - 10-27 26 + 10-48 52 - 5-93 66 - 8-17 44-60 - 10 31 28 + 10-43 54 - 5-98 58 - 8'22 62 - 10-35 45-30 + 10-38 56 - 6-02 43-60 - 8-26 64 - 10-39 32 + 10-33 58 - 6-06 62 - 8-30 66 - 10-43 34 + 10-28 42-60 - 6-10 64 - 8-34 68 - 10-47 36 + 10-23 62 - 6-15 66 - 8-38 44-70 - 10-51 38 + 10-18 64 - 6-19 68 - 8-42 72 - 10-55 45-40 + 10-13 66 - 6-24 43-70 - 8'47 74 - 10-59 42 + 10-08 68 - 6-28 72 - 8'51 76 - 10-63 44 + 10-03 42-70 - 6-33 74 - 8-65 78 - 10-67 46 + 9-99 72 - 6-37 76 - 8'69 44-80 - 10-71 48 + 9-94 74 - 6-41 78 - 8-64 82 - 10-75 45-50 + 9-89 76 - 6-45 43-80 - 8-68 84 - 10-79 62 + 9-84 78 - 6-50 82 - 8-72 86 - 10*84 54 + 9-79 42-80 - 6-54 84 - 8-76 88 - 10-87 56 + 9-75 82 - 6-59 86 - 8-80 44-90 - 10-91 58 f 9-70 84 - 6-63 88 - 8-84 92 - 10*95 45-60 + 9-65 86 - 6-68 43-90 - 8-89 94 - 10-99 62 + 9-60 88 - 6-72 92 - 8-93 96 - 11-03 64 + 9-55 42-90 - 6-76 94 - 8-97 98 - 11-07 66 + 9.60 92 - 6-80 96 - 9-01 46-00 - 11-11 68 + 9-46 94 - 6-85 98 - 9-05 45-70 + 9-41 96 - 6-89 44-00 - 9-09 72 + 9-36 98 - 6-94 02 - 9-14 74 + 9-31 43-00 - 6-98 04 - 9-18 76 + 9-27 02 - 7-02 06 - 9'22 78 + 9-22 04 - 7-06 08 - 9'26 45-80 + 9-17 06 - 7-11 44-10 - 9-30 82 + 9-12 08 - 7-15 12 - 9-34 84 + 9-07 43-10 - 7-20 14 - 9-38 86 + 9-03 12 - 7'24 16 - 9'42 88 + 8-98 14 - 7-28 18 - 9-47 45-90 + 8-93 16 - 7-32 44-20 - 9-51 92 + 8-88 18 - 7-37 22 - 9'55 94 + 8-84 43-20 - 7'41 24 - 9'59 96 + 8-79 22 - 7-45 26 - 9'63 98 f 8-75 24 - 7 : 49 28 - 9-67 46-00 1 + 8'70 26 - 7-54 44-30 - 9-71 02 r 3-66 332 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Meter Registering 50 Feet. Meter Registering 50 Feet. Meter Registering 50 Feet. Meter Registering 50 Feet. Reading of Scale Amount nf Reading of Scale Amount nf Reading of Scale Amount f\f Reading of Scale Amount * of Gas- holder. OI Error. of Gas- holder. OI Error. of Gas- holder. OI Error. of Gas- holder. OI Error. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. 46-04 + 8-60 47-08 + 6-20 48-12 + 3-91 49-16 + 1-71 06 + 8-56 47-10 + 6-16 14 + 3-86 18 + 1-67 08 + 8-51 12 + 6-11 16 + 3-82 49-20 + 1-63 46-10 + 8-46 14 + 6-07 18 + 3-77 22 + 1-59 12 + 8-41 16 + 6-02 48-20 + 3-73 24 + 1-55 14 + 8-37 18 + 5-98 22 + 3-69 26 + 1-50 16 + 8-32 47-20 + 5-93 24 + 3-65 28 + 1-46 18 + 8-28 22 + 5-89 26 + 3-60 49-30 + 1-42 46-20 + 8-23 24 + 5-84 28 + 3-56 32 + 1-38 22 + 8-18 26 + 5-80 48-30 + 3-52 34 4- 1-34 24 + 8-13 28 + 5-75 32 -f 3-48 36 + 1-29 26 + 8-09 47-30 + 5-71 34 + 3-44 38 + 1-25 28 + 8-0-1 32 + 5-67 36 + 3-39 49-40 + 1-21 46-30 + 7-99 34 + 5-62 38 + 3-35 42 + 1-17 32 + 7-94 36 + 5-58 48-40 + 3-31 44 + 1-13 34 + 7-90 33 + 5-53 42 + 8-27 46 + 1-09 36 + 7-85 47-40 + 5-49 44 + 3-22 48 + 1-05 38 + 7-8L- 42 + 5-44 46 -f 3-18 49-50 + 1-01 46-40 + 7-76 44 + 5-40 48 + 3-13 52 + 0-97 42 + 7-71 46 + 5-35 48-50 -4- 3-09 54 + 0-93 44 + 7-67 48 + 5-31 52 -f- 3-05 56 + 0-89 46 + 7-62 47-50 + 5-26 54 + 3-01 58 + 0-85 48 + 7-58 52 + 5-22 56 + 2-96 49-60 + 0-81 46-50 + 7-53 54 + 5'17 58 + 2-92 62 -f 0-77 52 + 7-48 56 + 5-33 48-60 + 2-88 64 + 0-73 54 + 7-44 58 + 5-08 62 + 2-84 66 + 0-68 56 + 7-39 47-60 + 5-04 64 + 2-80 68 + 0-64 58 + 7-35 62 + 6-00 66 + 2-75 49-70 + 0-60 40-60 + 7-30 64 + 4-95 63 + 2-71 72 + 0-56 62 + 7-25 66 + 4-91 48-70 + 2-67 74 + 0-52 64 + 7-21 68 + 4-80 72 + 2-63 76 + 0-48 66 + 7-16 47-70 + 4-82 74 + 2-59 78 + 0-44 68 + 7-12 72 + 4-78 76 + 2-54 49-80 + 0-40 46-70 + 7-07 74 + 4-73 78 + 2-50 82 + 0-36 72 + 7-02 76 + 4-69 48-80 + 2-46 84 + 0-32 74 + 6-98 78 + 4-64 82 + 2-42 86 + 0-28 76 + 6-93 47-80 + 4-60 84 + 2-38 88 + 0-24 78 f 6-89 82 + 4-56 86 + 2-33 49-90 + 0-20 46-80 + 6-84 84 + 4-51 88 + 2-29 92 + 0-16 82 + 6-79 86 + 4-47 48-90 + 2-25 94 + 0-12 84 + 6-75 88 + 4-42 . -92 + 2-21 96 + 0-08 86 + 6-70 47-90 + 4-38 94 + 2-17 98 + 0-04 88 + 6-66 92 + 4-34 96 -f 2-12 50-00 Nil. 46-90 + 6-61 94 + 4-30 98 + 2-08 02 - 0'04 92 + 6-56 96 + 4-25 49-00 + 2-04 04 - 0-08 94 + 6-52 98 + 4-21 02 + 2-00 06 - 0-12 96 + 6-47 48-00 + 4-17 04 + 1-96 08 - 0-16 98 + 6-43 02 + 4-13 06 + 1-91 50-10 - 0'20 47-00 + 6-38 04 k + 4-08 08 + 1-87 12 - 0-24 02 + 6-34 06 ,+ 4-04 49*10 + 1-83 . -14 - 0-28 04 + 6-29 08 + 3-99 12 + 1-79 16 - 0-32 06 + 6-25 48-10 + 3-95 14 + 1-75 ! 18 - 0-36 CONSUMERS' GAS METERS 333 Meter Registering 50 Feet. Meter Registering 50 Feet. Meter Registering 50 Feet. Meter Registering 50 Feet. Reading of Scale of Gas- holder. Amount of Error. Reading of Scale of Gas- bolder. Amount of Error. Reading of Scale of Gas- holder. Amount of Error. Reading of Scale of Gas- holder. Amount of Error. Feet Per Cent. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. 50-20 - 0-40 51-24 - 2-42 52-70 - 5-12 55-30 - 9-59 22 - 0-44 26 - 2-45 75 - 5-21 35 - 9-67 24 - 0-48 28 - 2-49 80 - 5-30 40 - 9-75 26 - 0-52 51-30 - 2-53 85 - 5-39 45 - 9-83 28 - 0-56 32 - 2-57 90 - 5-48 55-50 - 9-91 60-30 - 0-60 34 - 2-61 95 - 5-57 55 - 9-99 32 - 0-64 36 - 2-65 53-00 - 5-66 60 - 10-07 34 - 0-68 38 - 2-69 05 - 5-75 65 - 10-15 36 - 0'7l 51-40 - 2-72 10 - 5-84 70 - 10-23 38 - 0-75 42 - 2-76 15 - 5-93 75 - 10'31 60-40 - 0-79 44 - 2-80 20 - 6-02 60 - 10-39 42 - 0-83 46 - 2-83 25 - 6-10 85 - 10-47 44 - 0-87 48 - 2-87 30 - 6-19 90 - 10-55 46 - 0-91 51-50 - 2-91 35 - 6-28 95 - 10-63 48 - 0-95 52 - 2-95 40 - 6-37 5G - 00 - 10-71 60-50 - 0-99 54 - 2-99 45 - 6-45 05 - 10-79 52 - 1-03 56 - 3-02 63-50 - 6-54 10 - 10-87 54 - 1-07 58 - 3-06 55 - 6-63 15 - 10-95 56 - I'll 51-60 - 3-10 60 - 6-72 20 - 11-03 58 - 1-15 62 - 3-14 65 - 6-80 25 - ll'll 60-60 - 1-19 61 - 3-18 70 - 6'89 62 - 1-23 86 - 3-21 75 - 6-98 64 - 1-27 68 - 3-25 80 - 7-06 66 - 1-30 51-70 - 3-29 85 - 7-15 68 - 1-34 72 - 3-33 90 - 7-24 50-70 - 1-38 74 - 3-36 95 - 7-32 72 - 1-42 76 - 3-40 54-00 - 7-41 74 - 1-46 78 - 3-43 05 - 7-49 76 - 1-49 51-80 - 3-47 10 - 7-58 78 - 1-53 82 - 3-51 15 - 7-66 60-80 - 1-57 84 - 3-55 20 - 7-75 82 - 1-61 86 - 3-58 25 - 7-83 84 - 1-65 88 - 3-62 30 - 7-92 86 - 1-69 51-90 - 3-66 35 - 8-00 88 - 1-73 92 - 3-70 40 - 8-09 60-90 - 1-77 94 - 3-74 45 - 8-17 92 - 1-81 96 - 3-77 54-50 - 8-26 94 - 1-85 98 - 3-81 55 - 8-34 96 - 1-88 52-00 - 3-85 60 - 8-42 98 - 1-92 05 - 3-94 65 - 8-51 61-00 - 1-96 10 - 4-03 70 - 8-59 02 - 2-00 15 - 4-12 75 - 8-68 04 - 2-04 20 - 4-21 80 - 8-76 06 - 2-07 25 - 4-31 85 - 8-84 08 - 2-11 30 - 4-40 90 - 8'93 61-10. - 2-15 35 - 4-49 95 - 9-ei 12 - 2-19 40 - 4-58 55-00 - 9-09 14 - 2-23 45 - 4-67 05 - 9-18 16 - 2-26 62-50 - 4-76 10 - 9-26 18 - 2-30 55 - 4'S5 15 - 9-34 61-20 - 2-34 60 - 4-94 20 - 9-42 22 - 2-38 65 - 5-03 25 - 9-51 334 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Meter Eegistering 100 Feet, Meter ^Registering 100 Feet. Meter Eegistering 100 Feet. Meter Kegistering 100 Feet, Beading of Scale Amount f\f Reading of Scale Amount f\t Reading of Scale Amount $ Reading of Scale Amounk f\f of Gas- holder. ot Error. of Gas- holder. ot Error. of Gas- holder. 01 Error. of Gas- holder. 01 Error. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. Feet, Per Cent. 90'00 + ll'll 92-65 + 7' 1 J3 95-30 + 4-93 97-95 + 2-09 05 + 11-05 70 + 7-87 35 -f 4-87 98-00 + 2-04 10 + 10-99 75 + 7-82 40 + 4-82 05 + 1-99 16 + 10-92 80 + 7-76 45 + 4-76 10 + 1-94 20 + 10-86 85 + 7-70 95-50 + 4-71 15 + 1-88 25 + 10-80 90 + 7-64 55 + 4-65 20 + 1-83 30 + 10-74 95 + 7-59 60 + 4-60 25 + 1'78 35 + 10-68 93-00 + 7-53 65 + 4-54 30 + 1-73 40 + 10-62 05 + 7'47 70 + 4-49 35 + 1-68 46 + 10-56 10 + 7'41 76 + 4-43 40 + 1-63 90-50 + 10-50 15 + 7-36 80 + 4-38 45 + 1'57 56 + 10-44 20 + 7-30 85 + 4-33 98-50 + 1-52 60 + 10-38 25 + 7-24 90 + 4-28 55 + 1-47 65 + 10-31 30 + 7-18 95 + 4-22 60 + 1'42 70 + 10-25 35 + 7-13 96-00 + 4-17 65 + 1-37 75 + 10-19 40 + 7-07 05 + 4-11 70 + 1-32 80 + 10-13 45 + 7-01 10 + 4-06 76 -f 1-26 85 + 10-07 93-50 + 6-95 16 + 4-00 80 + 1-21 90 + 10-01 55 + 6-90 20 + 3-95 85 + 1-16 95 + 9-95 60 + 6-84 25 + 3-89 90 + I'll 91-00 + 9'89 65 + 6-78 30 + 3-84 95 + 1-06 05 + 9-83 70 + 6-72 35 + 3-78 99 '00 + 1-01 10 + 9-77 75 + 6-66 40 + 3-73 05 + 0-96 16 + 9-71 80 + 6-61 45 + 3-68 10 + 0-91 20 + 9-65 85 + 6-55 96-50 + 3-63 15 + 0-86 25 + 9-59 90 + 6-50 55 + 3-57 20 + 0-81 30 + 9-53 95 + 6-44 60 + 3-52 25 + 0-75 35 + 9-47 94-00 + 6-38 65 + 3-46 30. + 0-70 40 + 9-41 05 + 6-32 70 + 3-41 35 + 0-65 45 + 9-35 10 + 6-27 76 + 3-36 40 + 0-60 91-50 + 9-29 15 + 6-21 80 + 3-31 45 + 0-55 66 + 9-23 20 + 6-16 85 + 3-25 99-50 + 0-50 60 + 9-17 25 + 6-10 90 + 3-20 55 + 0-45 66 + 9-11 30 + 6-04 95 + 3-14 60 + 0-40 70 + 9'05 35 + 5-98 97-00 + 3-09 65 + 0-35 75 + 8-99 40 + 5-93 05 + 3-04 70 + 0-30 80 + 8-93 45 + 5-87 10 + 2-99 75 + 0-25 85 + 8-87 94-60 + 6-82 16 + 2-93 80 + 0-20 90 + 8-81 55 + 5-76 20 + 2-88 85 + 0-15 95 + 8-76 60 + 5-71 25 + 2-82 90 I 0-10 92-00 + 8-70 66 + 5-65 30 -f 2-77 95 + 0-05 06 + 8-64 70 -f 5-60 35 + 2'72 100-00 Nil. 10 + 8-68 75 + 5-54 40 + 2-67 05 - 0-05 15 + 8-62 80 + 5-49 45 + 2-61 10 - o-io 20 + 8-46 85 + 6-43 97-50 + 2-56 15 - 0-15 25 + 8-40 90 + 6'37 65 + 2-51 20 - 0-20 30 + 8-34 95 + 6-31 60 + 2-46 25 - 0-25 35 + 8-29 95-00 + 6-26 65 + 2-40 30 - 0-30 40 -f 8-23 05 + 5-20 70 + 2-35 35 - 0-35 46 + 8-17 10 + 6-15 75 + 2-30 40 - 0-40 92-50 + 8-11 15 + 6-09 80 + 2'25 45 - 0-45 66 + 8-05 20 + 6-04 '85 -f 2-20 100-50 - 0-50 60 + 7-09 25 4- 4-9H 90 4- 2-15 fifl - 0-65 CONSUMERS' GAS METERS 335 Meter Registering 100 Feet. Meter Registering 100 Feet. Meter Registering 100 Feet. Meter Registering 100 Feet. Beading of Scale of Gas- holder. Amount of Error. Beading of Scale of Gas- holder. Amount of Error. Beading of Scale of Gas- holder. Amount of Error. Beading of Scale of Gas- holder. Amount of Error. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. Feet. Per Cent. 100-60 - 0-60 103-25- - 3-15 105-90 - 5-57 108-55 - 7'88 65 - 0-65 30 - 3'19 95 - 5-62 60 - 7-92 70 - 0-70 35 - 3-24 106-00 - 5-66 65 - 7-96 75 - 0-75 40 - 3-29 05 - 5-71 70 - 8-00 80 - 0-79 45 - 3'34 10 - 5-75 76 - 8-05 85 - 0-84 103-50 - 3-38 15 - 5-80 80 - 8-09 90 - 0-89 65 - 3-43 20 - 5-84 85 - 8-13 95 - 0-94 60 - 3-47 25 - 5-88 90 - 8-17 101-00 - 0-99 65 - 3-52 30 - 5-93 95 - 8-22 05 - 1-04 70 - 3-57 35 - 5-98 109-00 - 8-26 10 - 1-09 75 - 3-61 40 - 6-02 05 - 8-30 15 - 1-14 80 - 3-66 45 - 6-06 10 - 8-34 20 - 1-19 85 - 3-71 106-50 - 6-10 15 - 8-38 25 - 1-24 90 - 3-75 55 - 6-15 20 - 8-42 30 - 1-28 95 - 3-80 60 - 6-19 25 - 8-47 35 - 1-33 104-00 - 3-85 65 - 6-24 30 - 8-51 40 - 1-38 05 - 3-90 70 - 6-28 35 - 8-55 45 - 1-43 10 - 8-94 75 - 6-33 40 - 8-59 101-50 - 1-48 15 - 3-99 80 - 6-37 45 - 8-64 55 - 1-53 20 - 4-03 85 - 6'41 109-50 - 8-68 60 - 1-57 25 _ 4-08 90 - 6-45 55 - 8-72 65 - 1-62 30 _ 4-12 95 - 6-50 60 - 8-76 70 - 1-67 35 _ 4-17 107-00 - 6-54 65 - 8-80 75 - 1-72 40 - 4-21 05 - 6-59 70 - 8-84 80 - 1-77 45 - 4-26 10 - 6-63 75 - 8-89 85 - 1-82 104-50 - 4-31 15 - 6-68 80 - 8-93 90 - 1-87 55 - 4-36 20 - 6-72 85 - 8-97 95 - 1-91 60 - 4-40 25 - 6-76 90 - 9-01 102-00 - 1-96 65 - 4-45 30 - 6-80 95 - 9-05 05 - 2-01 70 - 4-49 . -35 - 6-85 110-00 - 9-09 10 - 2-06 75 - 4-54 40 - 6-89 10 - 9-18 16 - 2-10 80 - 4-58 45 - 6-94 20 - 9-26 20 - 2-15 85 - 4-63 107-50 - 6-98 30 - 9-34 25 - 2-20 90 - 4-67 55 - 7-02 40 - 9-42 30 - 2-25 95 - 4-72 60 - 7-06 50 - 9-51 35 - 2-30 105-00 - 4-76 65 - 7-11 60 - 9-59 40 - 2-34 05 - 4-81 70 - 7-15 70 - 9-67 45 - 2-39 10 - 4-85 75 - 7-20 80 - 9-75 102-50 -. 2-44 16 - 4-90 80 - 7-24 90 - 9-83 55 - 2-49 20 - 4-94 85 - 7-28 111-00 - 9-91 60 - 2-53 25 - 4-99 90 - 7-32 10 - 9-99 65 - 2-58 30 - 5-03 95 - 7-37 20 - 10-07 70 - 2-63 35 - 5-08 108-00 - 7-41 30 - 10-15 75 - 2-68 40 - 5-12 05 - 7'45 40 - 10-23 80 - 2-72 46 - 5-17 10 - 7-49 60 - 10-31 85 - 2-78 105-50 - 5-21 15 - 7-54 60 - 10-39 90 - 2-82 55 - 5-26 20 - 7-58 70 - 10-47 95 - 2-87 60 - 5-30 25 - 7-62 80 - 10-55 103-00 - 2-91 65 - 5-35 30 - 7-66 90 - 10-63 05 - 2-96 70 - 5-39 35 - 7-71 112-00 1 - 10-71 10 - 3-01 75 - 5-44 40 - 7-75 10 1 - 10-79 15 - 3-06 80 - 5-48 45 - 7-79 20 - 10-87 20 - 3-10 85 - 5'53 108-50 - 7-83 30 -- 10 -9* 336 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS NOTE. Any other quantity may be calculated by the rule of proportion, thus : Meter registering loo'oo feet Reading of scale of test gasholder . . 89*95 ,, Difference 10-05 89-95 : 100 : : 10*05 : 11-17 fast. And meter registering 100*00 feet Reading of scale of test gasholder . . 112-55 ,, Difference 12-55 ii2'55 : ioo : : 12-55 : H'i5 slow. TABLE Showing the Dilatation of Gas in Contact with Water and Saturated with Aqueous Vapour, for Given Temperature. (Professor Airey.) (Used in making Corrections for Temperature in the Testing of Gas Meters.) Temperature in Fahrenheit's Percentage of Temperature in Fahrenheit's Percentage of Temperature in Fahrenheit's Percentage of Scale. Dilatation. Scale. Dilatation. Scale. Dilatation. 31-40 54-33 5* 74-30 11 33-54 1 56-24 6 75-94 ia 35-70 1 58-12 6| 77-23 12 37-84 11 60-02 7 78-81 Mi 39-91 2 62-00 71 80-40 13 42-05 2i 63-77 8 81-94 18* 44-17 3 65-63 8i 83-44 14 46-22 3i 67-43 9 84-88 M4 48-25 4 69-18 91 86-39 15 50-32 70-90 10 87-83 161 52-36 5 72-60 10J 89-20 16 NOTE. The table shows the percentage of increase of the volume of gas above its volume at the temperature of 31 -4 Fahr. INTERNAL FITTINGS. The advantages of an ample supply of good and pure gas are frequently neutralised by the defective manner in which premises are fitted internally. Bad gas-fittings are generally the result of cupidity or ignorance. They are a common cause of complaint from consumers who are often ready to attribute the inefficient light which they afford to a want of pressure or purity, or a low illuminating power in the gas. INTERNAL FITTINGS 337 In the matter of internal fittings, the gas manager, by judgment and tact, can exercise a useful supervision even without the aid of statutory powers ; and his advice in regard to the sizes of pipes, and the kind of burners and lamps to be used in different situations, will generally be accepted and acted upon. The following regulations (with such additions and modifica- tions as may be found necessary) may be adopted with advantage by gas authorities. Regulations as to Internal Fittings. 1. The Company's (or Local Authority's) servants will in all cases lay on the service pipe, conveying the same through the outer wall of the premises to be supplied with gas. 2. The main-cock must be attached to the end of the service pipe within the building and close to the outer wall. 3. The gas meter must be placed perfectly level, either on the floor or on a substantial support, and within 2 ft. 6 in. of the main -cock. 4. The piping attached to the meter, whether inlet or outlet, must not be smaller in internal diameter than that of the meter unions. 5. The following are the sizes of meters and their measur- ing capacity, from which the number of lights which they supply can be readily calculated : Wet Meters. Size of Meters. Size of Inlet and Outlet. < Measuring Capacity pe Revolution. r. i Measuring Capacity per Hour. Inches. Cub. Ft. Cub. Ft. 2-light | A 12 3 | 18 5 10 i g 15 i 90 20 ij i 120 30 H i 180 if 3 300 360 80 j 3. 4 480 100 , 2 5 600 150 , 3 7i 900 200 , 3 10 I20O 250 4 12^ 1500 300 , 4 15 1800 400 , 4 20 24OO 500 , 5 25 3000 600 , 5 30 3600 v 338 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS Dry Meters. Size of Inlet and Outlet. Inches. Size of Meters. 2-light 3 5 10 20 30 50 60 80 IOO 1 20 150 20O 250 300 4OO 500 600 8oc- IOOO To ascertain the number of lights which any size of meter will supply, divide the measuring capacity per hour by the quantity of gas per hour which each jet is estimated to consume. Example : What number of lights, consuming 4 cub. ft. of gas per hour, will a 20-light meter supply ? Then, - =30 lights. 4 6. The following are the sizes and lengths of iron, lead, or composition tubes to be used according to the number of ordinary lights : Greatest No. of Burners allowed. 3 6 12 20 Measuring Measuring Capacity per Capacity per Revolution. Hour. Cub. Ft. Cub. Ft. 0*083 12 0'125 18 0'200 30 Q'333 60 0-500 120 0-833 180 I-428 300 1-666 360 2*500 480 2-857 600 3*333 720 S'ooo 900 6-666 1200 7-333 1500 S'333 1800 14*250 2400 2O'OOO 3000 22'222 3600 25-000 4800 33*333 6000 Internal Diameter Greatest Length of Tubing. allowed. Inches. Feet. 1 20 I 30 1 40 & 50 i 70 jl IOO ii 150 2 200 2 i 300 3 450 IOO 200 300 450 Tubing of J-inch bore is not allowed to be used. 7. The tubes or pipes must be laid with proper fall, and in such a manner that they are easily accessible, and protected from liability to damage. Attention is to be given to leaving a space INTERNAL FITTINGS 339 round them at such places as wall crossings, etc., where fracture or crushing of the pipes might be caused by the subsidence of the building. The joining of the tubes and pipes is to be made in the most solid and substantial manner, and carefully rounded bends (not elbows) are to be used wherever the direction of a pipe is changed. 8. Floor boards covering pipes must be secured with screws, so that they may be easily removed to afford access to the pipes, especially at the points of connection. 9. On the completion of the work of fitting, and before the piping is covered up, notice thereof must be given in writing to the gas manager (the requisite form for that purpose being obtained at the gas office), who will cause an inspection to be made of the work, and if found in accordance with the regulations herein con- tained, it will be passed by the Company (or Local Authority), and the gas turned on. 10. If the regulations are not conformed to in every respect, the Company (or Local Authority) reserve the right to refuse a , supply of gas until the necessary alterations are made. 11. Gas-fitters complying with these regulations have their names registered on the Company's (or Local Authority's) list of approved fitters, and they are at liberty to designate themselves " Authorized Gas-Fitters." Repeated negligence will cause the licence to be withdrawn. A handy and useful apparatus for testing the soundness of gas-fittings, has been devised by Harrison & Sheard. It con- sists of a small force pump and a King's pressure gauge, in which mercury is employed instead of water ; the two being connected together on one base board, and provided with a coupling for ready attachment to the fittings to be tested. To use the apparatus, air is forced, by means of the pump, into the fittings, until the pressure therein is equivalent to, say, 12 in. of water, as indicated on the dial of the gauge. The pump is then shut off by means of a stopcock, and it is noted whether the pressure is maintained or falls away. If the pointer remains stationary, the fittings are sound ; while if it goes back there is leakage. To facilitate the discovery of leakages, gas may be forced into Z 2 340 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS the fittings by connecting an inlet pipe on the pump, by means of india-rubber tubing, with any convenient gas supply, when the gas escaping through the defective fittings at a high pressure enables the locality of the leakages to be readily discovered. Another device for the same purpose is the " Reliable " leak testing machine of James Milne & Son. Ordinary dining and sitting-rooms are best lighted by means of a central pendant. When the room is of large dimensions, wall brackets may be added. A bracket at each side of the mantlepiece has a tasteful appearance, and lights are handy in that position. The burners of the pendants should be not less than 36 in. from the ceiling. In the case of the old water-slide pendants, many of which are still in use, a teaspoonful of salad oil added on the top of the water in the tube tends, in a great measure, to prevent or retard evaporation of the water. The system of incandescent gas-lighting is a notable advance in artificial illumination, and is now in all but general use. The designs of the burners, upright and inverted, and the variety of fittings, plain and ornamental, are innumerable. All the specialists in street lighting cater for private lighting. The Welsbach lamp consists of a Bunsen burner, on which is suspended a mantle composed of a textile filament coated with thorium and cerium oxides. On lighting the burner, the textile portion is consumed, leaving the refractory portion in position, and this becomes incandescent, giving out a strong steady light. The fragility of the mantle was a hindrance to its early adoption, but this has proved to be less of a drawback than was at first anticipated, as is shown by the fact of the universal application of the system. The saving of gas that is effected by its use, the increase in illuminating effect, and the comparative coolness of the light, with the subsequent improvements in construction, have earned for it a deserved reputation. Various improvements have been made in the mantle as originally devised by Welsbach. Ramie fibre is being largely used in substitution of cotton fibre, the former being less friable. The Welsbach-Plaissetty is a cotton fibre mantle, but before being impregnated with the thorium and cerium oxides, is heated by a special process, which prevents shrinkage. INTERNAL FITTINGS 341 Copper-cellulose has also been introduced as a base for the mantle, with a view to increasing its durability. After the burning-off process all mantles are dipped in a collodion or silica solution to facilitate handling and export. A novelty in domestic lighting is the " Telephos " apparatus for lighting and extinguishing. It consists of a dry cell, controller, spitfire igniter, a length of twin wire, and a push. The controller is fitted in the supply pipe above the lamp, and from this the gas and electric current pass to form the by-pass. On pressing the push, which may be arranged at a convenient place on the wall, the gas supply is turned on and the by-pass is ignited by the electric spitfire. On relieving the push the by-pass is extinguished. Another pressing of the button turns the light out. This arrangement is also fitted to lamps with a number of burners, and is specially designed for use in shop windows and other places where a permanent by-pass may be objectionable. Ventilating Lights The question of the efficient ventilation of rooms where gas is being consumed is of importance both to the gas producer and the user. Ventilating globe and other lights of various designs have been introduced by Sugg, Cowan, Bray, Strode, Wenham (whose lamp is also regenerative), and other makers, with highly satisfactory results. Fig. 182 shows one of Cowan's ventilating lights, and Fig. 183 the ventilating sunlight as made by Strode ; either flat- flame or incandescent burners may be adopted. An interesting and novel arrangement is the " Nonpareil " Ventilating Gas Sun burner of James Mime & Son (Figs. 184 and The burner is fitted with by-pass ignition and special lowering and raising facilities ; and is exceptionally well suited for places of public assembly. The burner may be constructed with 9, 16, or 28 inverted lights with an illuminating power ranging from 675 to 2100 candles. The shaft above the burner is connected with a duct leading to the outside of the building, and is suitable for any type of roof. Flat flame burners are still in considerable use in bedrooms, cellars and as flare-lights. The burners of this class made by Sugg and Bray are so well known as to need no recommendation. Shades, moons, or globes, as they are variously named, have 342 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS kept pace with the improvements in burners ; being constructed not only of better and purer materials than formerly, but accord- ing to scientific principles. At one time they were invariably made with the bottom openings about 2 in. in diameter ; the effect being to direct the current FIG. 183. of air upon the flame, lowering the temperature, impairing the illuminating effect, and causing an unpleasant flickering. These have given place to globes with openings at least 4 in. in diameter, whereby the foregoing defects are entirely obviated, whilst the concave sides also act as reflectors of the light in the downward direction, especially below 45 from the horizontal. As Professor Lewes points out : "In order to gain any true idea of illuminating INTERNAL FITTINGS 343 effect, it is necessary to take the light emitted over all the working angles, and not on the horizontal plane." FIG. 184. FIG. i84A. Globes made of good and suitable materials, and untinted, 344 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS diffuse the light without seriously obstructing it, even when the test is applied on the horizontal plane. This is particularly noticeable with the "holophane " globe and with the pure white opal globes. To obtain the maximum of light from a burner, the pressure, when that is in excess in the mains, as it must necessarily be, should be controlled and regulated in the passage of the gas to the point of ignition. This cannot be accomplished satisfactorily by checking either the taps on the fittings or the stopcock at the meter, because there is a continual variation of pressure according to the consumption that is in progress. The house governor or regulator was invented to achieve that -end. It may be fixed on the pipe leading from the meter outlet, or, what is better, on the principal pipe supplying each floor-level of the premises. Peebles's and Stott's governors are of this class and are extensively used. The regulator is automatic in its action ; and when weighted to afford the required pressure for all the burners in use, it will continue to give a practically uniform supply, however much the pressure in the mains may vary, or whether the whole or only a portion of the burners being supplied through it may be alight at one time. Sugg's regulator gas-burner, Peebles's " Needle " governor burner, and the " Acme " regulating burner of Wright, are examples of regulation applied close to the point of consumption. Dr. Letheby found that a vulcanized india-rubber tube of about 30 ft. in length reduced the power of a weak gas to the extent of nearly 25 per cent., by absorbing the illuminating hydro- carbons. Varnish to Prevent the Escape of Gas through India-Rubber Tubing. i J parts treacle. 2 ,, gum arabic. 7 ,, white wine. 3j ,, strong alcohol. First dissolve the treacle and gum in the white wine, and afterwards add the alcohol very slowly, constantly stirring the mixture to prevent the gum from being thrown down. INTERNAL FITTINGS 345 LEAD AND COMPOSITION PIPES FOR GAS. Weights per Yard, and Lengths usually Manufactured. LIGHT. HEAVY. Weight Lengths of iameter per Bundles Weight Lengths of Diameter per Bundles Inside. Yard. usually Inside. Yard. usually Lbs. Oz. Manufactured. Lbs. Oz. Manufactured. : m. o n 80 yards. Jin. o 15 67 yards. 12 60 1 i 6J 46 20 32 f 2 10 l6 24 25 1 30 20 33 23 3 12 19 48 26 i 60 20 j 80 16 J i IO 12 \ 12 10 z i 14 o 9 18 o 5 2 . 21 5 BRASS TUBE PLAIN WEIGHT PER FOOT. Weight. ; Diameter. Weight. Lbs. Oz. In. Lbs. Oz. 0-08 or i'28 J 0*50 or 8'oo 0-15 2-40 [i 0'59 9'44 o'ig li o'8i 12*96 0'2I 3-36 i I '00 i6'oo 0-25 4'oo if I'I2 17-92 0-31 4-96 2 I'25 2O'OO o'37 5'92 2* 1-50 24'00 6'88 3 r8 7 29-92 Diameter In. & ' The size of brass and copper tubes is measured by the outside diameter. BRASS TUBE, SPIRAL AND FLUTED WEIGHT PER FOOT. Diameter. In. I 13 Spiral. Fluted. Spiral. Fluted. Weight . Weight. Diameter. Weight. Weight. Oz. Oz. In. Oz. Oz. 3 2f J 6 6 : : 3 al 3i 1 . S , 7i 7 i ... 9 8 . 4i 4 ii .... 12 ii 5 5 if . - -' 15 14 346 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS SOLDERS. Fine Solder is an alloy of 2 parts of block tin and i of lead (melts at 360 Fahr.). This is used for fine work such as soldering the drums of meters, for pewter, etc. Glazing Solder. Equal parts of block tin and lead. Used for lead. Plumbing Solder. I part -block tin, 2 lead. For all kinds of plumbers' joints and for tin and zinc. Solder for Copper. Hard : 3 parts brass, i zinc. Soft : 8 parts brass, i zinc. Brazing Solder or Spelter. Hard : i part copper, i zinc. Soft : 4 parts copper, 3 zinc, i block tin. For fine brass work : i part silver, 8 copper, 8 zinc. Solder for Steel. 19 parts silver, 3 copper, i zinc. Pewterers' Soft Solder. 2 parts bismuth, 4 lead, 3 tin. Common : i part bismuth, i lead, 2 tin. FLUXES FOR SOLDERING. Iron and steel . . . Borax or sal ammoniac. Tinned-iron . . Resin or zinc chloride. Copper and brass . . Sal ammoniac or zinc chloride. Lead and composition pipes . Resin and sweet oil. Zinc ..... Zinc chloride. FOR TINNING BRASS OR IRON. | oz. muriatic acid. J oz. mercury. J oz. ground block tin. Mix together, and dilute the whole with a small quantity of cold water. Apply with the finger or a cork. BRAZING. The edges of the articles, either iron or brass, to be brazed are scraped thoroughly clean, covered with the brazing solder or spelter in the form of borings or turnings sprinkled over with powdered borax, and exposed to the heat of a clear fire till the solder flows. A smokeless coke or gas fire is best for the purpose. In brazing iron, a covering of loam is sometimes placed over the solder, to exclude the air, till it melts. INTERNAL FITTINGS 347 BRONZE. 1 quart common vinegar. 2 oz. sal ammoniac. i oz. blue stone (copper sulphate). The sal ammoniac and blue stone are well pounded, and then allowed to dissolve in the vinegar. The solution, when ready, is laid on with a common brush, black-leaded whilst damp, and then polished. Lacquer is then applied as described hereafter. Green Bronze. To imitate the antique. 1 quart of common vinegar. 2 oz. verdigris. i oz. sal ammoniac. Boil for a quarter of an hour, filter through paper, and dilute with water. Immerse the article to be bronzed until it acquires- the green tinge desired ; then wash carefully, and dry in sawdust. Bronze Powders. These can be purchased from any dealer in artists' material- They are prepared as follows : Copper Bronze Powder. Strips of copper are dissolved in nitric acid in a glass vessel, and then strips of iron are added, when the dissolved copper is precipitated in the form of a very fine powder. This powder is washed with water and dried, and is then ready for use. Gold Bronze Powder, or Aurum Mosaicum, Is the basis of many bronze powders. Any desired colour can be produced by mixing it with the common dry pigments. Thus a red bronze powder is obtained by grinding red lead with it ; and a green by the use of verdigris. It is prepared in the following manner : One pound of tin is melted in a crucible, and then poured cautiously into an iron dish containing half a pound of mercury. When cold it is reduced to powder, mixed with - seven ounces of flowers of sulphur, and eight ounces of 348 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS sal ammoniac, and triturated in a mortar. The mixture is then calcined in a flask, which expels the sulphur, mercury, and ammonia, and leaves a residuum in the form and colour of. a bright flaky gold powder. Size for Bronze Powders. The size is made by boiling four ounces of gum animi to every pound of pure linseed oil in a flask, until the mixture is of the consistency of cream, after which it is diluted with turpentine as required. The article to be bronzed is coated, by means of a soft brush, with this size ; and when nearly dry, a piece of soft leather is wrapped round the finger, dipped into the powder, and rubbed gently over it. Or it may be laid on with a camel's-hair pencil, and then left to dry thoroughly, after which all the loose powder is brushed off. The bronze may also be mixed with a strong solution of isinglass, and applied in the moist state, like varnish, with a brush. This latter mode, however, is not suitable for articles exposed to the weather. For Silvering Metals. Silver nitrate, 10 parts. Common salt, 10 Cream of tartar, 30 ,, Moisten with water when ready to apply, and lay the mixture on with a soft brush. LACQUER AND VARNISH. The solution of spirits of wine and shellac, known as " simple pale " lacquer, is the basis of most other lacquers. The two ingredients in their proper proportions, as stated overleaf, are put into a jar or bottle, and allowed to remain for forty-eight hours, being briskly shaken three or four times during the interval. At the expiration of the time named, most of the shellac will be dissolved. The mixture is then carefully strained through filtering paper, to free it from grit and other foreign substances, and to remove any particles of un dissolved shellac that may remain. INTERNAL FITTINGS 349 Different tints or shades, producing red, green, yellow, etc., are obtained by mixing with the pale lacquer various colouring ingredients, such as dragon's blood, arnotto, gamboge, turmeric, saffron, etc. The proper way of adding these is to stir them in a cup with a small quantity of the pale lacquer, afterwards strain- ing the whole through a piece of thin cloth or gauze, and filtering if necessary. The article to be lacquered is heated slightly by means of a steam kettle or stove ; or it may be held over a hot iron plate till just as hot as to allow of its being touched by the finger .without burning. The heat must not be greater than this. The lacquer is then applied with a soft camel's-hair brush. Simple Pale Lacquer. i pint of spirits of wine. 4 oz. of shellac. Fine Pale Lacquer. i pint of spirits of wine, i oz. of pure white shellac. 1 dr. of gamboge. 2 drs. of Cape alces. Fine Pale Lacquer, for Silvered or Tinned Work. i pint of spirits of wine, i oz. of pure white shellac. Gold Lacquer. 1 pint of spirits of wine. 3 oz. of shellac. J oz. of turmeric. 2 drs. of arnotto. 2 drs. of saffron. Deep Gold Lacquer. i pint of spirits of wine. 3 oz. of shellac. J oz. of turmeric. 4 drs. of dragon's blood. Red Lacquer. i pint of spirits of wine. 4 oz. of shellac. 4 drs. of dragon's blood, i dr. of gamboge. Yellow Lacquer. 1 pint of spirits of wine. 2 oz. of shellac. 2 drs. of gamboge. 4 drs. of Cape aloes. Green Lacquer for Bronze. i pint of spirits of wine. 4 oz. of shellac. 4 drs. of turmeric. \ dr. of gamboge. Iron Lacquer. 1 quart of turpentine. | Ib. of pitch. 2 oz. of shellac. 350 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS To Clean Old Brass Work for Lacquering. Boil a strong lye of wood ashes, and strengthen with soap lees ; put in the brass work, and the old lacquer will come off. Next dip it in a solution of nitric acid and water strong enough to remove the dirt ; wash it immediately in clean water ; dry well, and lacquer. Varnish for Iron Work. Boil a quantity of gas tar for four or five hours, till it runs as thin as water ; add one quart of turpentine to a gallon of the tar, and boil another half-hour. Apply the varnish whilst hot. Golden Varnish. Pulverize I drachm of saffron and J a drachm of dragon's blood, and put them into one pint of spirits of wine. Add 2 ounces of gum shellac and 2 drachms of Soccotrine aloes. Dissolve the whole by gentle heat. Yellow painted work, varnished with this mixture, will appear almost equal to gold. Glue Cement to Resist Moisture. i part glue, i part black resin. J part red ochre. Mix with a very small quantity of water. COAL GAS TESTING APPLIANCES AND METHODS. A gas may have a high illuminating power, and yet contain impurities that ought to be removed. Purity is not always in the ratio of illuminating power. TESTS FOR IMPURITIES. The tests for the detection of impurities in coal gas, after it has undergone the different processes of purification, are the following : Test for Ammonia. Expose yellow turmeric paper slightly moistened with water, or litmus paper first reddened by any weak TESTS FOR IMPURITIES 351 acid, to a jet of unlighted gas for about a minute. If the yellow colour of the turmeric be turned to brown, or if the blue of the litmus be restored, ammonia is present. Turmeric and litmus papers may be purchased at the chemist's, or they can be prepared as follows : Turmeric Paper. Six parts by weight of spirits of wine are added to one of turmeric powder in a stoppered bottle, and well shaken up occasionally for three days. A portion of the clear fluid is then poured on a plate, and pieces of unsized white filtering paper well soaked therein. These are then dried in air, cut into strips J in. wide and 2 in. long, and kept for use in a bottle away from the light. Litmus Paper. Six parts by weight of water to one of powdered litmus, shaken well together, allowed to stand for several days, and then filtered. Pieces of white filtering paper are then thoroughly soaked in the solution, dried, and cut into strips, which should be kept in a close stoppered bottle, excluded as much as possible from the air and light. Should it be desired to redden the solution, add (after filtra- tion) a small quantity of very dilute sulphuric acid, gradually, drop by drop, until the pink or neutral tinge is obtained. Test for Carbon Dioxide Make a solution of pure barytes, and pass the gas through it. If carbon dioxide is present, barium carbonate will be precipitated ; or pass the gas through clear lime water, and calcium carbonate will be precipitated. It may also be detected by adding to water impregnated with the gas a few drops of sulphuric acid, when minute bubbles of carbon dioxide will be rapidly disengaged. Lime Water is prepared by agitating slaked lime with dis- tilled water in a bottle or other vessel. It is then allowed to stand until the excess of lime has been deposited, when the clear- liquid is poured off, and filtered through filtering paper. Test for Sulphuretted Hydrogen. Moisten a piece of writing-paper with a solution of lead acetate in distilled water, and expose it for not less than a minute to a jet of unlighted gas. If sulphuretted hydrogen be present, the paper will be browned or blackened. A solution of silver nitrate is a more delicate test than the above. This requires to be kept in a bottle coated outside with 352 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS tinfoil, and placed in a drawer or other dark place to protect it from the influence of the light. Lead .paper may be made of white filtering paper soaked in the lead acetate solution, then dried, cut into slips, and kept in a well-corked bottle for use. But the solution applied to the paper at the time of making the test is preferable. The Gas- Works Clauses Act, 1871, Schedule A, contains the following regulations in respect of the apparatus and mode of testing for this impurity : Apparatus. " A glass vessel (Fig. 185) con- taining a strip of bibulous paper moistened with a solution of lead acetate, containing 60 grs. of crystallized lead acetate dissolved in one fluid ounce of water. Mode of Testing " The gas shall be passed through the glass vessel containing the strip FIG 185 ^ brt> u l us paper moistened with the solution of the lead acetate for a period of three minutes, or such longer period as may be prescribed ; and if any discoloration of the test paper is found to have taken place, this is to be held conclusive as to the presence of sulphuretted hydrogen in the gas." Test for Sulphur. The sulphur present in gas, due to compounds other than sulphuretted hydrogen, notably carbon bisulphide, is estimated by burning a jet of the gas at the rate of i cub. ft., or J cub. ft. per hour, for twenty-four hours, from a Leslie or other burner arranged within the wide end of a trumpet tube whose upper and smaller end is inserted in a condenser, from the opposite end of which a tube carries off the uncondensed vapour, and creates a current through the apparatus. (See Fig. 186.) Through the lower and wide end, where the burner is fixed, a supply of air, to support combustion, enters, carrying with it the vapour of ammonia from liquid ammonia or pieces of the carbonate contained in a suitable receptacle surrounding the burner. The ammonia combining with the sulphurous acid from the gas flame is deposited within the condenser as sulphite and sulphate of ammonia, from which the quantity of sulphur per 100 cub. ft. of gas is calculated. Mr. J. T. Sheard's method of estimating carbon dioxide in coal COAL GAS TESTING 353 FIG. 186. gas consists in passing a definite volume of gas through a solution of barium hydrate of known strength, which absorbs the carbon dioxide out of the gas ; the amount of free hydrate remaining after the operation being determined by 'titration with deci-normal hydrochloric acid. Either the volume or the weight of impurity that has been absorbed can thence be calculated. The gas absorption tube is of the form shown in Fig. 187 ; the straight part above the bulbs being filled with glass beads. To make a test, two absorption tubes are charged with 20 or 30 c.c. each, of a barium hydrate solution, the strength of which has been accurately determined by titration with deci-normal acid, and which should be approximately of equal strength with the acid. The apparatus being con- nected up as shown (Fig. 187 A), 500 c.c. of gas are drawn by means of the aspkator slowly through the liquid, and followed immediately, without stopping the cur- rent, by an equal quantity of air, which is done by slipping off the india-rubber tube at the inlet of the apparatus, as the water running from the aspirator passes the mark of a 500 c.c. flask, and then running out a further quantity of 500 c.c. into another flask held in readiness. The bulbs are then washed down with water free from carbon dioxide, a few drops of phenol-phthalein (suffi- cient to impart a distinct purple red colour to the liquid) added, and the whole titrated with deci-normal hydrochloric acid the acid being added a few drops at a time, with frequent agitation of the liquid until the colour is destroyed. The amount of barium hydrate that has been neutralized is equivalent to the amount of carbon dioxide absorbed from 500 c.c. of gas ; from which the percentage of the impurity present, or its weight per cubic foot of gas, can be determined. EXAMPLE. Two gas absorption tubes charged, respectively, with 30 c.c. and 20 c.c. of barium hydrate solution. One cubic centimetre of the barium hydrate having previously been found by N experiment as equivalent to 1*09 of acid. 10 2 A 354 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS ist Tube. 2nd Tube. Equivalent of barium hydrate employed . . 327 c.c. 21*8 c.c. - acid required to neutralize resultant liquid 21 '6 c.c. 21 '4 c.c. ii'i c.c. o'4 c.c. Then = 2*77 per cent, by volume of COo 0-914 grm. 11*5 c - c - X 0*0022 grm. X 15*432 grs. X 28,315 c.c. __ 500 c.c. grains of CO 3 per cubic foot of gas. 1 FIG. 187. FIG. These calculations may be shortened by employing the factor 0*241 for percentage by volume, and 1*92 for grains per cubic foot. Thus 11*5 X 0*241 = 2*77 per cent, by volume of C0 3 11*5 X 1*92 =22*1 grs. of CO 3 per cubic foot of gas. 1 It may be explained that o - oo22 grm. is the weight of CO.. to which i c.c. of acid is equivalent. t IO 0-914 grm. is the weight of 500 c.c. of CO-? saturated with moisture. 15-432 grs. is the value of i grm. 28,315 c.c. is the value of i cubic, foot. COAL GAS TESTING 355 A complete test can be made in fifteen minutes, and perfectly accurate results obtained. The apparatus is equally applicable to the estimation of ammonia and sulphuretted hydrogen in the gas, the former being absorbed by sulphuric acid of deci-normal strength, and the latter by a 10 per cent, solution of copper sulphate. When sulphu- retted hydrogen is passed into an aqueous solution of cupric sulphate, a precipitate of cupric sulphide is deposited, and free sulphuric acid is formed in the solution, previously neutral. After filtering out the precipitate, the acidity of the solution can be determined by titration with deci-normal ammonia, using N methyl ' orange as indicator. Each cubic centimetre of ammonia required to neutralize the solution represents 1*48 grs. of sulphuretted hydrogen per cubic foot of gas. Likewise each N cubic centimetre of - - acid neutralized by the ammonia in the 10 gas represents 1*48 grs. of ammonia per cubic foot of gas. The manipulation of the apparatus is the same as above described for carbon dioxide, and all three impurities may be deter- mined in the same sample of gas. For this purpose one absorp- tion tube is charged with acid for absorbing ammonia, followed by one containing cupric sulphate for sulphuretted hydrogen, and this by the tubes containing barium hydrate for carbon dioxide. Then 500 c.c. of gas are drawn through the whole series, followed by 1000 c.c. of air to clear the apparatus. The subsequent treat- ment will be understood from what has gone before. Harcourt's Colour Tests. This is one of the most useful apparatus in the gas manager's laboratory for determining with ease and celerity the amount of carbon bisulphide, sulphuretted hydrogen, and carbon dioxide in coal gas. The following is a description of the test, and directions for its use : Testing for Carbon Bisulphide. The arrangement of the colour test is shown in Fig. 188 ; the fire-clay cylinder being represented by dotted lines. The bulb, which is filled with platinized pumice, is to be so adjusted that it may be about an inch above the burner, and in the middle of the cylinder. To use the apparatus, turn on first the upper stopcock, send- ing gas through the bulb at the rate of about half a cubic foot an hour, as may be judged by lighting the gas for a moment at the 2 A 2 356 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS end of the horizontal arm, when a flame about an inch in length should be produced. Raise the cylinder, which will be supported by the pressure of the wires, light the burner, and turn down the flame till it forms a blue non-luminous ring. Lower the cylinder, and place the small clay pieces upon it round the neck of the bulb. FIG. 188. A testing may be made five minutes after the burner is lighted, except when the apparatus is first used, when the gas should be allowed to flow through the bulb for a quarter of an hour, or a little longer, and any number of testings, one after another, as long as the heat is continued. The mode of testing is as follows : Lay a piece of white paper on the table by the side of the burner, and fix a piece of cardboard upright in the brass clip ; the cardboard serves as a background against which to observe the colour of the contents of the glasses, and should receive a side light, and be as clear as possible from shadows. Fill one glass (once for all) up to the mark with standard coloured liquid, and cork it tightly. Dilute some of the lead syrup with twenty times its volume of distilled water, and fill the other glass up to the mark with a portion of 'the liquid thus COAL GAS TESTING 357 prepared. Insert the caoutchouc plug with capillary tube and elbow tube, and connect, as shown in the figure, with the bulb and aspirator, placing the two glasses side by side. The aspirator should be full of water at starting, and the measuring cylinder empty. Turn the tap of the aspirator gradually ; a stream of bubbles will arise through the solution of lead. Turn off the tap for a minute, and observe the liquid at the bottom of the capillary tube. If it gradually rises, the india- rubber connections are not air-tight, and must be made so before proceeding. Avoid pressing the plugs into the glass or the aspirator while they are connected, which would drive up the lead solution into the inlet tube. When the connections are air-tight, let the water run into the measuring cylinder in a slender stream until the lead solution has become as dark as the standard. As the ascending bubbles interfere somewhat with the observation of the tint, it is best to turn off the tap when the colour seems almost deep enough ; compare the two ; turn on the tap, if necessary, for a few moments, then compare again ; and so on, till the colour of the two liquids is the same. The volume of water which the measuring cylinder now con- tains is equal to the volume of gas which has passed through the lead solution. This volume of gas contained a quantity of sulphur as carbon bisulphide which, as lead sulphide, has coloured the liquid in the test glass up to the standard tint. The standard has been made such that, to impart this tint to the volume of liquid, 0*0187 gr. of lead sulphide must be present, containing 0*0025 gr. of sul- phur. Hence, supposing the measuring cylinder, each division of which corresponds to 7 fiW cu ^- ^-> to nave ^ een filled to the 3oth division, yjJSiT cub. ft. of gas contained 0*0025 r - of sulphur. From this ratio the number of grains of sulphur existing as bisulphide in 100 cub. ft. of the sample of gas tested can easily be calculated. The following table gives the relation between (V) the divisions of the measuring cylinder filled with water and (S) the grains of sulphur existing as bisulphide in 100 cub. ft. of gas. Since gas contains, besides carbon bisulphide, some other sulphur com- pounds which are not transformed into sulphuretted hydrogen by the action of heat, and which contain sulphur amounting ordi- narily to 7 or 8 grs. in 100 cub. ft., this quantity must be added 358 NEWBIGGING'S HANDBOOK FOR GAS ENGINEERS to that found by the test, if it is wished to know approximately the total amount of sulphur. S = 5 V V S V S V S V S 10 50-o 33 I5'i 56 8-9 79 6'3 ii 45'4 34 I4'7 57 - 8-8 80 6-2 12 417 35 I4'3 58 8-6 81 6-2 13 SB'S 36 I3'9 59 8'5 82 6-1 14 35'7 37 I3'5 60 8-3 83 6-0 15 33'3 38 13-2 61 8'2 84 6-0 16 3i'3 39 I2'8 62 8'i 85 5'9 17 29-4 40 12-5 63 7'9 86 5'8 18 27-8 41 I2'2 64 7'8 87 5'7 19 26-3 42 II'9 65 7'7 88 5'7 20 25'o 43 ire 66 7'6 89 5'6 21 23-8 44 1 1-4 67 T5 90 5'6 22 .22-7 45 in 68 7'4 9i 5"3 23 217 46 io'9 69 7'2 92 5'4 24 20-8 47 io'6 70 7'i 93 5*4 25 2O'0 48 10-4 71 TO 94 5'3 26 19-2 49 I0'2 72 6'9 95 5'3 27 18-5 50 10-0 73 6-9 96 5'2 28 I7'9 5i 9-8 74 6-8 97 5'2 29 I7'2 52 9'6 75 6-7 98 5'i 30 i6'7 53 9'4 76 6'6 99 5'i 31 16-1 54 9-2 77 6*5 100 5'o 32 I5'6 55 9'i 78 6'4 150 3'3 For the next testing the test glass is to be disconnected and recharged. The water in the measuring cylinders is poured back into the aspirator. The colour of the standard is unaffected by exposure to light, but deepens if the liquid is warmed, returning to its original shade as the liquid cools. If, therefore, the glass containing the standard has been in a warm place, it must be let cool before testing. The liquid which has been used becomes colourless after being exposed to the light for a few hours, and may thus be used over and over again for twenty times or more, if it is not allowed to absorb carbon dioxide from the air. The best mode of working is to have two well-corked flasks, into one of which the coloured liquid is emptied while the glass is recharged from the other. Testing for Sulphuretted Hydrogen and Carbon Dioxide. The apparatus may also be used without the bulb tube and stand to test the amount of sulphuretted hydrogen or carbon dioxide in gas at any stage in its purification. COAL GAS TESTING 359 The gas is led in this case directly into the test glass, which is charged with lead solution for sulphuretted hydrogen, and with a saturated solution of barium hydrate (baryta water) for carbon dioxide. When the gas contains more than 50 grs. of sulphur as sul- phuretted hydrogen in 100 cub. ft. a smaller cylinder, containing 2^ cub. ft., is used to measure the volume of liquid run from the aspirator. The divisions on the smaller cylinder are tenths of the corresponding divisions on the larger cylinder ; therefore when it is used the numbers under S in Table I. must be read as whole numbers by omitting the decimal points. TABLE II. V C V C V C V C 10 0-72 33 0'22 56 0-13 79 0*09 ii 0-65 34 0-21 57 O'i3 80 0*09 12 o'6o 35 0-21 58 0'12 8l o'og 13 0-55 36 0*20 59 0'12 82 0*09 14 0-51 37 0'20 60 0'12 83 0*09 15 0-48 38 0*19 61 0'12 84 o'og 16 o*45 39 0-18 62 O'll 85 0-08 17 0-42 40 0-18 63 o'li 86 o - o8 18 0-40 41 0-17 64 O'll 87 o'o8 19 0-38 42 O'i7 65 o-ii 88 0-08 20 0-36 43 0-17 66 CTII 89 0-08 21 0'34 44 0-16 67 o-ii 90 0-08 22 0-33 45 0-16 68 o'li 91 o'o8 23 0-31 46 O'i6 69 o'io 92 o'o8 24 0-30 47 0-15 7o o'io 93 o'o8 25 0*29 48 0-15 71 o'io 94 0-08 26 0*28 49 0-15 72 o'io 95 0-08 27 0-27 50 0-14 73 O'lO 96 0-07 28 0-26 51 0-14 74 o'io 97 0*07 2