Vacuum Cleaning Systems A Treatise on the Principles and Practice of Mechanical Cleaning BY M. S. COOLEY, M. E. \\ MECHANICAL ENGINEER IN OFFICE OF THE SUPERVISING ARCHITECT, TREASURY DEPARTMENT, WASHINGTON, D. C. FIRST EDITION New York: HEATING AND VENTILATING MAGAZINE COMPANY, 1123 Broadway \ I* Copyright, 1913, BY HEATING AND VENTILATING MAGAZINE Co. CONTENTS. CHAPTER I. HISTORY OF MECHANICAL CLEANING. PAGE Early Attempts 3 Limitations of the Carpet Sweeper 4 Compressed Air Cleaners 5 Vacuum Produced by Compressed Air 7 Compressed Air Supplemented by Vacuum 7 Piston Pump the First Satisfactory Vacuum Producer. . . 9 Systems Using Vacuum Only 11 Renovator with Inrush Slot 13 Steam Aspirators Used as Vacuum Producers 14 Piston Pump Used Without Separators 15 First Portable Vacuum Cleaner 15 First Use of Stationary Multi-Stage Turbine Blowers 16 Separators Emptying to Sewer by Air Pressure 18 Machines Using Root Blowers as Vacuum Producers 18 CHAPTER II. REQUIREMENTS OF AN IDEAL VACUUM CLEANING SYSTEM. Necessity and Proper Location of Stationary Parts 24 CHAPTER III. THE CARPET RENOVATOR. Four Important Parts of Vacuum Cleaning System- 25 The Straight Vacuum Tool 26 Renovator with Auxiliary Slot Open to Atmosphere 27 Renovator with Two Cleaning Slots 30 Renovator with Inrush Slots on Each Side 30 Tests on Dirty Carpets 30 iii iv CONTENTS PAGE Type A Renovator Most Efficient on Dirty Carpets 36 Tests of Carpets " Artificially" Soiled 36 Effort Necessary to Operate Various Type of Renovators. . 51 Relative Damage to Carpets with Various Type of Reno- vators 52 CHAPTER IV. OTHER RENOVATORS. Different Form of Renovator Necessary to Clean Walls, Ceilings and Similar Flat Surfaces 60 Upholstery Renovators Disastrous to Surfaces Cleaned ... 64 Attempts to Overcome Destructive Tendency of Straight- Slot Upholstery Renovator 64 Upholstery Renovators Most Serviceable Clothing Cleaners. 65 Special Renovators for Cleaning Stairs . . . 66 Renovation of Furs 66 Renovation of Pillows 66 CHAPTER V. STEMS AND HANDLES. Use of Drawn Steel Tubing for Stems of Cleaning Tools. . 70 Drawn Aluminum Tubing for Long Stems 71 Swivel Joints Between Renovator and Stem 72 Wear on Hose Near Stem 74 Methods of Overcoming Wear of Hose 74 Valves to Cut Off Suction 78 CHAPTER VI. HOSE. Early Types Made of Canvas- Wound Rubber Tubing 80 Standard Weight Adopted 80 First Type Produced Especially for Use in Vacuum Clean- ing Work 81 First Attempt to Produce Light- Weight Hose 81 Other Types 82 CONTENTS v PAGE Hose Couplings 82 Hose Friction 84 Effect of Hose Friction 88 Most Economical Hose Size for Carpet and Floor Renovators 93 Conditions for Plant of Small Power 97 Limit of Length for Hose 99 CHAPTER VII. PIPE AND FITTINGS. Hose Inlets . . 100 Pipe Friction , 107 Determination of Proper Size Pipe 107 Determination of Number of Sweepers to be Operated. . . . 113 Determination of Number of Risers to be Installed 115 Size of Risers 115 Illustration of Effect of Long Lines of Piping 120 CHAPTER VIII. SEPARATORS. Classification of Separators 127 Primary Separators 127 Secondary Separators 130 Complete Separators 134 Total Wet Separator 138 CHAPTER IX. VACUUM PRODUCERS. Types of Vacuum Producers 142 Displacement Type 142 Centrifugal Type 142 Power Required to Produce Vacuum 142 Reciprocating Pumps 143 Rotary Pumps 148 Centrifugal Exhausters 156 Steam Aspirators 162 vi CONTENTS CHAPTER X. CONTROL. PAGE First Type of Controller 166 Second Form of Control 168 Appliances for Varying Speed of Motor-Driven Vacuum Pump 171 CHAPTER XI. SCRUBBING SYSTEMS. First Real Mechanical Scrubbing Device 176 Combining Scrubbing with Dry Cleaning 177 Ideal Separator for Use with a Combined Cleaning and Scrubbing System 173 CHAPTER XII. SELECTION OP CLEANING PLANT. Renovators 179 Hose 182 Pipe Lines 182 Separators 182 Vacuum Producers 183 Control 183 Selection of Appliances for Four Classes of Work 184 CLASS 1. Plant for Residence or Small Office or De- partmental Building, to be Not More than One- Sweeper Capacity. CLASS 2. Large Office or Departmental Building Where Carpet Cleaning is Important and Pipe Lines are of Reasonable Length. CLASS 3. Large Building or Group of Buildings Where Carpet Cleaning is Important and Long Lines of Piping are Necessary. CLASS 4. Large or Small Plant Where Carpet Clean- ing is Not an Important Function of the Cleaning System CONTENTS vii CHAPTER XIII. TESTS. Early Methods of Testing 187 Most Rational System of Testing 189 Use of Vacometer 190 Proper Orifice to be Used with Each Class of Plant 191 CHAPTER XIV. SPECIFICATIONS. Award of Contracts on Evaluation Basis 193 Determination Basis of Evaluation 193 Specification for Class 1, Plant for Residence or Small Office Building of One-Sweeper Capacity 194 Specification for Class 2, Plant for Large Office Building Having Pipe Lines of Moderate Length 204 Specification for Class 3, Large Installation, with Unusually Long Pipe Lines 209 Specification for Class 4, Large or Small Plant Where Carpet Cleaning is of Secondary Importance 215 Specification for Class 5, To Give Widest Competition .... 218 CHAPTER XV. PORTABLE VACUUM CLEANERS. Power Required 228 Weight of Efficient Portable Cleaners 228 Limit of Power Consumption When Attached to Lighting System 229 Disadvantage of Having Dust Bag at Outlet of Fan 230 Portables Equipped with Mechanically-Operated Brushes. . 231 Portables Exhausting Air Inside of Building 231 TABLES. PAGE 1. Cleaning Tests of Dirty Carpets 34 2. Cleaning Tests of Carpets Filled with Quicksand 38 3. Cleaning Tests Using 1 oz. of Sand per Square Yard of Carpet 40 4. Comparison of Tests Made by Mr. Reeve and by the Author 48 5. Effort Necessary to Operate Cleaning Tools 51 6. Vacuum Required at Hose Cock to Operate Type A Renovators Attached to Varying Lengths of Different- Sized Hose 89 7. Air Quantities and Vacuum at Renovator with 1-in. Hose and 10 in. Vacuum at Hose Cock 90 8. Air Quantities and Vacuum at Renovator with 1^4-in. Hose and 6 in. Vacuum at Hose Cock 90 9. Vacuum Required at Hose Cock to Operate Type C Renovators with Various Lengths of Three Sizes of Hose 91 10. Air Quantities Through Floor Brush with Various Sizes and Lengths of Hose, Operated on Same System with Type A Renovators 92 11. Horse Power Required at Hose Cock to Operate Bare Floor Brushes on Same System with Type A Reno- vators 93 12. Free Air Passing Brush Type of Bare Floor Reno- vator Operated on Same System with Type C Carpet Renovators 94 13. Horse Power at Hose Cock with Brush Type of Bare Floor Renovator Operated on Same System with Type C Carpet Renovators 94 ix x TABLES 14. Cubic Feet of Free Air Passing the Felt-Covered Floor Renovator Operated on Same System with Type A Renovators 96 15. Horse Power Required at Hose Cock to Operate Felt- Covered Floor Renovators Operated on Same System with Type A Renovators 96 16. Vacuum at Hose Cock with 2 in. Vacuum at Type A Renovator 97 17. Air Quantities when Bristle Bare Floor Renovators are Used in Conjunction with Type A Carpet Renovators at 2 in. Mercury 98 18. Pipe Sizes Required, as Determined by Air Passing Renovators 109 19. Friction Loss in Pipe Lines, with Carpet Renovators in Use Exclusively 109 20. Pressure Losses from Inlet to Separator in System for Cleaning Railroad Cars 121 ILLUSTRATIONS. FIG. PAGE. 1. Early Type of Mechanical Cleaning Nozzle Using Com- pressed Air 6 2. Another Type of Compressed Air Cleaning Nozzle, Supple- mented with Vacuum Pipe 8 3. Separators Used With Combined Compressed Air and Vacuum Machines 9 4. Piston Type of Vacuum Pump, Mounted Tandem With Air Compressor 9 5. Mr. Kenney's First Renovator. Vacuum Alone Being Used as Cleaning Agent 10 6. Air Compressors Arranged for Operation as Vacuum Pumps n 7. Separators Installed by Mr. Kenney in Frick Building 12 8. Vacuum Renovator With Inrush Slot, Introduced by the Sanitary Devices Manufacturing Company 13 9. First Portable Vacuum Cleaner, Constructed by Dr. William Noe, of San Francisco, in 1905 16 10. Late Type of Spencer Vacuum Cleaning Machine, Operated by Multi-Stage Turbine Blowers 17 1 1. Type A, the Straight Vacuum Tool 26 12. Type B, with Wide Slot and Wide Bearing Surface 26 13. Type C, with Auxiliary Slot, Open to Atmosphere 28 14. Type D, with Two Cleaning Slots 28 15. Type E, with Inrush Slot on Each Side of Vacuum Slot. ... 31 16. Type F, an Exaggerated Form of Type B 31 17. Tests of Three Renovators on Dirty Carpets 35 1 8. Cleaning Tests of Carpets Filled with Quicksand 39 19. Cleaning Tests Using I oz. of Sand Per Square Yard of Carpet 41 20. Three Series of Tests with Kenney Type A Renovators 45 21. Tests by Mr. Reeve, Using Type C Renovator 46 22. Tests by Mr. Reeve, Using Type D Renovator 47 23. Tests Showing Efficiency of Different Types of Renovators at Different Degrees of Vacuum 50 24. Early Type of Bare Floor Renovator 55 25. Later Type of Bare Floor Renovator 55 26. Another Type of Bare Floor Renovator 56 27. Bare Floor Renovator with Felt Cleaning Surface 57 28. Bare Floor Renovator with Unusual Form of Slot 58 29. Bare Floor Renovator with Hard Felt or Composition Rub- ber Strips 58 xi xii ILLUSTRATIONS FIG. PAGE. 30. Bare Floor Renovator with Rounded Wearing Surface 59 3oa. The Tuec School Tool 62 31. Round Bristle Brush for Carved or Other Relief Work 62 32. Rubber-Tipped Corner Cleaner for Use on Carved or Other Relief Work 62 33. Early Type of Upholstery Renovator 63 34. Upholstery Renovator with Narrow Slots to Prevent Damage to Furniture 64 35. Another Type of Upholstery Renovator with Short Slots ... 65 36. Hand Brush Type of Renovator 65 37. Form of Swivel Joint Connecting Stem to Renovator 72 38. Swivel Joint Arranged to Prevent Dust Lodging Between the Wearing Surfaces 73 39. Swivel Joint in Use 74 40. Another Use of Swivel Joint, Showing Possibilities of this Form 75 41. Operator Cleaning Trim of Door with Swivel Joint 76 42. Swivel Joint, with Screwed Union 76 43. Swivel Joint Having Ball Bearings 76 44. Action of Bail-Bearing Swivel Joint 77 45. Illustration of Defects of Plug Cocks 78 46. Bayonet Type of Hose Coupling, Introduced by the American Air Cleaning Company 82 47. All Rubber Hose Coupling Used by the Spencer .Turbine Cleaner Company 83 48. Chart for Determining Hose Friction 86 49. Effect of Increase of Velocity on the Friction Loss 88 50. Another Test Showing Friction Loss Due to Velocity 89 51". Inlet Cock to Prevent Air Leakage when Not in Use 101 52. Type of Automatic Self-Closing Inlet Cock 102 53. "Smooth Bore" Pipe Coupling 103 54. Joint Made of Standard Pipe Flanges 104 55. Standard Durham Recessed Drainage Fittings Generally Used in Vacuum Cleaning Installations 105 56. Friction Loss in Pipe Lines 106 57-60. Diagrams Showing Operation of Brush and Carpet Re- novators Under Different Conditions no 61. Typical Floor Plan of Office Building Illustrating Number of Sweepers Required 114 62. Plan of Layout for Office Building Showing Best Loca- tion (at d) for Vacuum Producer 118 63. Vacuum Cleaning Layout for a Passenger Car Storage Yard 122 64. Arrangement of Piping Recommended as Best for Passenger Car Storage Yard 123 65. Good Location for Dust Separator Where Large Areas Are Served by One Cleaning System 125 ILLUSTRATIONS xiii FIG. PAGE. 66. Location of Separators at Centers of Groups of Risers for Large Systems 126 67. Early Type of Primary Separator, Used by Vacuum Cleaner Company 128 68. Primary Separator Used by the Sanitary Devices Manu- facturing Company 128 69. Primary Separator Used by the General Compressed Air and Vacuum Cleaning Company 129 70. Primary Separator Made by the Blaisdell Engineering Co... 129 71. Secondary Separator Used by the Vacuum Cleaner Company 131 72. Secondary Separator Used by the General Compressed Air and Vacuum Cleaning Company 131 73. Secondary Separator Used by the Sanitary Devices Manu- facturing Company 132 74. Type of Dry Separator Used as Secondary Separator 134 75. Form of Complete Separator Used by the Vacuum Cleaner Company '. 135 76. Complete Separator Brought Out by the Electric Renovator Manufacturing Company 136 77. Complete Separator Made by the American Radiator Company 137 773. Interior Construction of Dunn Vacuum Cleaning Machine 140 78. Power Consumption and Efficiency of Air Compressor Used as a Vacuum Pump 143 79. Modification of Reciprocating Pump Made by the Sanitary Devices Manufacturing Company 144 80. Power Consumption and Efficiency of Modified Reciprocating Pump 145 81 and 82. Indicator Cards for Clayton and Modified Pumps. .. . 146 83. One of the Pumps Installed in Connection with the Vacuum Cleaning System in the New York Post Office, the Largest Reciprocating Pump Used for this Purpose up to ^ the Present 148 84. Interior Arrangement of the Garden City Rotary Pump.... 149 85. Power Required to Operate Garden City Type of Rotary Pump 150 86. Arrangement of Double-Impeller Root Type Rotary Pump for Vacuum Cleaning Work I5 1 87. Rotary Pump Arranged with Double-Throw Switch for Re- versing Pump 1 5 2 88. Power Consumption and Efficiency of Root Type of Pump.. 153 89. The Rotrex Vacuum Pump, Used by the Vacuum Engineer- ing Company 153 90. Late Type of Centrifugal Exhauster Made by the Spencer Turbine Cleaner Company 154 91. Power and Efficiency Curves for the Spencer Machine 155 xiv ILLUSTRATIONS FIG. PAGE. 92. Interior Arrangement of Invincible Machine, Manufactured by the Electric Renovator Manufacturing Company.... 156 93. Power Consumption, Vacuum and Efficiency of First Types of Invincible Machine 157 94. Power Consumption, Vacuum and Efficiency of Invincible Machine After Valve Was Fitted to Discharge 158 95. Four-Sweeper Invincible Plant Installed in the United States Post Office at Los Angeles, Cal 159 96. Centrifrugal Pump with Single Impeller, Manufactured by by The United Electric Company 161 963. Test of Centrifugal Pump with Single Impeller 162 97. Steam Aspirator Used by the American Air Cleaning Company 163 98. Steam Consumption of Steam Aspirator 164 99. First Type of Controller Introduced by the Sanitary De- vices Manufacturing Company, known as the "Unload- ing Valve" 167 100. Test of Controller Connected to Suction of 8-Sweeper Piston Pump 168 101. Type of Controller for Use on Pumps Without Valves 169 102. Regulator for Motor-Driven Vacuum Pump, Manufactured by the Cutler-Hammer Manufacturing Company 170 103. Inspirator Type Vacuum Contactor, Used to Control Pilot Motor of Cutler-Hammer Controller 171 104. Vacometer for Use in Testing Vacuum Cleaning Systems... 190 PREFACE. The contents of this work are compiled from the observations of the author through the seven years during which he has been engaged in the preparation of specifications for, and the testing of, complete plants installed in the buildings under the control of the Treasury Department. During this time it has become necessary to alter no less than five times the stock form of specifications for stationary vacuum cleaning plants which were adopted by the Government, with the intent of obtaining the widest competition possible with efficient and economical operation, in order to keep pace with the variation and improvement in the apparatus manufactured. As each new type of system has come on the market a personal investigation at the factory, together with tests, has been made. An exhaustive test of carpet renovators was also conducted, using one of the Government plants. In addition the vaco- meters recommended for use in capacity tests were carefully calibrated, using the machine at the Department of Agriculture. The writer wishes to acknowledge the aid received from the various manufacturers in furnishing illustrations and data on their machines, to Messrs. Ewing & Ewing and Prof. Sidney A. Reeve for data on tests made by Prof. Reeve and used in de- fending the Kenney basic patent. In analyzing the results of his tests and observations, the writer has endeavored to put his own conclusions into concrete form for the use of the consulting engineer and has not entered into the problems to be encountered in the design and manu- facture of the various forms of apparatus. CHAPTER I. HISTORY OF MECHANICAL CLEANING. Early Attempts. Whenever machinery has been introduced to assist or replace manual labor, the earlier attempts have been in imitating the tools formerly used by man. As the earliest mechanically-propelled carriages were mechanical walking ma- chines, the earliest steamboats mechanical rowing machines, and the earliest flying machines mechanical birds, so were the earliest mechanical cleaners in the form of mechanical brooms. These mechanical brooms were introduced about 1880 and took the form of the well-known street sweeper, with a large circular brush mounted on a four-wheeled cart and rotated by means of gearing driven from the wheels, the propelling power being the horses which drew the machine. This machine at once made itself unpopular with the resi- dents of the streets cleaned on account of its great activity in stirring up dust, because the streets were swept dry. This trouble was later overcome to a considerable extent by sprink- ling the streets before sweeping, but only at a sacrifice in efficiency of cleaning, especially where such uneven surfaces as cobble or medina stone blocks formed the surface of the roadway. Various attachments were added to reduce this dust nuisance, but none has apparently been successful, as we see these machines in their original form in use today. Almost simultaneously with the introduction of the street sweeper came its counterpart, the carpet sweeper, with a similar but smaller brush, enclosed in a wood and metal case, the brush being driven by friction from the wheels supporting the box and the power for operation being derived from the person who pushed the machine along the floor. This machine has not been modified to any great extent dur- ing the thirty odd years of its existence. It is today in prac- 3 4 VACUUM CLEANING SYSTEMS tically its original form, and is doing no better work than when first introduced. This form of mechanical cleaner occupied the field of household cleaning for nearly twenty years without a rival, during which time it won its way into the hearts and hands of many housekeepers in this and other countries. Limitations of the Carpet Sweeper. This device, with its light brush and equally light pressure on the surface cleaned and its limited capacity for carrying the material picked up, has never been a thorough cleaner in any sense of the word, and has been and is now used only to take up that portion of the usual litter and light dust which is located directly on the surface, and is, therefore, most annoying to the housekeeper, owing to its being visible to the eye. Because of its generous proportions, made necessary to accommodate the material picked up, and its centrally-pivoted handle, made necessary by its mechanical construction, it is impossible to operate it under low furniture. Like the lawn mower, it must be in motion in order to operate its revolving brush, on which its cleaning action is dependent. It is impossible to make use of same in corners, along walls, or close to heavy furniture, its use being limited to a literal slicking up of those portions of the carpet in the most conspicuous portions of the apartment. In spite of these serious defects it came into, and is still in, nearly universal use, even in households equipped with the latest approved types of mechanical cleaners. Its use on bare floors has never been even a moderate success and in no case has it superseded the broom and dust pan of our grandmothers Compressed Air Cleaners. Compressed air has been in use for many years in foundries and machine shops, for cleaning castings and producing certain finishes on metal. With the introduction of modern electrical machinery it was rapidly adapted to the cleaning of windings and other inaccessible parts of this machinery. Its first use in cleaning buildings was un- doubtedly in the form of an open jet for dislodging dust from carvings and relief work, for which purpose it is very efficient as a remover of the dust from the parts to be cleaned and also as a distributor of this same dust over the widest possible area for subsequent removal by other means. It has a draw-back in that the expansion of air both cools the same and reduces HISTORY OF MECHANICAL CLEANING 5 its ability to retain moisture, resulting in the deposit of mois- ture on the surfaces cleaned. About 1898, attempts to overcome the objections to the open air jet and to produce a commercially successful compressed air carpet cleaner were undertaken almost simultaneously by two companies, the American Air Cleaning Company, of Mil- waukee, operating under the Christensen patents, and the General Compressed Air Cleaning Company, of St. Louis, oper- ating under the Thurman patents. The renovator used by the American Air Cleaning Com- pany consisted of a heavy metal frame, about 18 in. long and 12 in. wide, having mounted on its longer axis a wedge-like nozzle extending the entire length of the frame, with a very narrow slit, 1/64 in. wide, extending the entire length of its lower edge. This nozzle was pivoted and so connected to the operating handle, by which the renovator was moved over the floor, that when the renovator was alternately pushed and pulled over the surface to be cleaned, the slot was always inclined in the direction in which the renovator was being- moved. The top of the renovator was closed by a canvas bag, smaller at the neck than in its center, which was supported by a wire hook. Air was introduced into the nozzle, at a pressure of from 45 to 55 Ibs. per square inch, and issued from the slot in a thin sheet which impinged on the carpet at an angle. The frame was held close to the carpet by its weight, preventing the escape of the air under its lower edge. The air striking the carpet at an angle was deflected up into the bag, inflating same like a miniature balloon. The dust loosened from the carpet by the impact of the air was carried up into the bag where it lodged, the air escaping through the fabric of the canvas into the apartment. The renovator used by the General Compressed Air Clean- ing Company differed from the above-described renovator in that it contained two nozzles, with slots inclined at fixed angles to the carpet. A pair of hand-operated valves were provided in the handle to introduce air into the nozzle which was inclined in the direction in which the renovator was moving; other- 6 VACUUM CLEANING SYSTEMS wise the renovator was identical with that used by the Mil- waukee company. These renovators were generally supplied with air from a portable unit, consisting of an air compressor, driven by a gaso- line engine mounted with the necessary gasoline and air storage tanks on a small truck. One of these machines was in use in Washington last year, but its use at that time was very limited and it is not to be seen this year. These trucks were drawn up in front of the building to be cleaned and a large-size hose, usually 1^4 in. in diameter, was carried into the house and attached to an auxiliary tank from which y 2 -in. diameter hose lines were carried to two or more renovators. A few buildings were equipped with air compressors and pipe lines, with outlets throughout the building for use with this type of renovator, among which was the Hotel Astor in New York City. These renovators, the construction of which is shown diagram- matically in Fig. 1, required approximately 35 cu. ft. of free FIG. I. EARLY TYPE OF MECHANICAL CLEANING NOZZLE USING COMPRESSED AIR. air per minute at a pressure of from 45 to 53 Ibs. per square inch and were usually driven by a 15 H. P. engine. The renovators were very heavy to carry about, although their operation with the air pressure under them was not difficult. However, their operation was complicated, requiring HISTORY OF MECHANICAL CLEANING 7 skilled operators. Owing to their generous proportions it was impossible to clean around furniture, making its removal from the apartment necessary, and limiting their use to the cleaning of carpetts at the time of general house cleaning. The cooling effect of the expansion of the air in the nozzle often caused condensation of moisture on the carpets when the relative humidity was high. They were also at a disadvantage in that all the heavy dust collected in the canvas bag had to be carried from the apartment by hand. Owing to the constant agitation of the dust in the bag by the entering air currents, much of the finer particles of dust and all the disease germs liberated by the renovator were blown through the bag back into the apartment. They were not, therefore, by any means sanitary devices. Vacuum Produced by Compressed Air. The General Com- pressed Air Cleaning Company also introduced another form of renovator for use with their compressed air plants. This was composed of an ejector operated by compressed air, with a short hose attached to a carpet renovator of the straight nar- row-slot type, such as was used later in vacuum cleaning sys- tems. The outlet from this ejector was connected by another short hose to a metal box containing a canvas bag, woven back- wards and forwards over metal frames to give a large surface for the passage of air. The dust picked up by the suction of the ejector was carried with the air into the box and there separated from the air, which escaped through the canvas into the apartment. This form of renovator overcame some of the objections to the former type in that there was no condensation of moisture on the carpets, and it was possible to operate the renovator under and around furniture, and even on portieres and other hangings. However, the apparatus was rendered inefficient by the resistance of the bag, causing a back pressure on the injector which greatly reduced its air-drawing capacity. Compressed Air Supplemented by Vacuum. Shortly after these two companies began operation, the Sanitary Devices Manufacturing Company, of San Francisco, introduced a new system of mechanical cleaning under the Lotz patents. This 8 VACUUM CLEANING SYSTEMS system used a renovator having a compressed air nozzle ter- minating in a narrow slot, similar to the nozzles of the Amer- ican and Thurman systems, but differing from them in that the slot was fixed vertically, pointing downward. This nozzle was surrounded by an annular chamber having an opening at the bottom of considerable width. The whole formed a reno- vator about 14 in. long and not over 2 in. wide at its base. In addition to the compressed air connection to its nozzle, a second hose, 1 in. in diameter, was connected to the annular space surrounding the nozzle and led to a vacuum pump by which the air liberated through the nozzle, together with the dust which "was liberated from the carpet, was carried from the apartment. The construction of this renovator is shown dia- grammatically in Fig. 2. Vacuum- ~ ~/^ Air, FIG. 2. ANOTHER TYPE OF COMPRESSED AIR CLEANING NOZZLE, SUPPLEMENTED WITH VACUUM PIPE. As dust-laden air was not suitable to be carried through the pump used as a vacuum producer, separators had to be pro- vided to remove the dust from this air before it reached the pump. The separators used consisted of two cylindrical tanks. The air was introduced into the first tank in such a way that a whirling motion was imparted to it, thus separating the heavier particles of dust by centrifugal force. The second tank contained water which was brought into intimate contact with the air by means of an atomizer located in the pipe con- nection between the two tanks, thus washing the air in a man- ner somewhat similar to the familiar air washers used in con- nection with mechanical ventilating systems. The air and spray then entered the second tank, above the water line, where HISTORY OF MECHANICAL CLEANING 9 the entrained water separated on the reduction of velocity and fell back into the water below, to be recirculated through the FIG. 3. SEPARATORS USED WITH COMBINED COMPRESSED AIR AND VACUUM MACHINES. atomizer. The air passed on out of the top of the tank to the pump. An illustration of these separators is shown in Fig. 3, Piston Pump the First Satisfactory Vacuum Producer. Various types of apparatus were tried as vacuum producers, including an air ejector, such as was used with the Thurman Vacuum Discharge--' Compressor In take- 1 FIG 4 PISTON TYPE OF VACUUM PUMP, MOUNTED TANDEM WITH AIR COMPRESSOR. 10 VACUUM CLEANING SYSTEMS renovator, and found to be ineffective due to its inability to overcome the back-pressure necessary to discharge the air through the hose, which was placed on its outlet. A rotary pump was next tried, but, owing to the selection of an in- efficient type, this was abandoned and, finally, a piston-type vacuum pump, with very light poppet valves and mounted tan- dem with the air compressor, was adapted and remained in use with this system until straight vacuum was adopted, when the air compression cylinder was omitted. This pump is illus- trated in Fig. 4. FIG. 5. MR. KENNEY'S FIRST RENOVATOR, VACUUM ALONE BEING USED AS CLEANING AGENT. In this system we see the first sanitary device to be intro- duced into the field of mechanical cleaning, as the dust and germ-laden air were removed entirely from the apartment and purified before being discharged into the outside atmosphere. The foulness of the water in the separators clearly showed the amount of impurities removed from the air. HISTORY OF MECHANICAL CLEANING 11 These machines were mounted on wagons, similar to their forerunners, and were also installed in many buildings as stationary plants, among which were the old Palace Hotel and the branch Mint, in San Francisco, and the old Fifth Avenue Hotel, in New York City. Systems Using Vacuum Only. In 1902 David T. Kenney, of New York, installed the first mechanical cleaning system in which vacuum alone was used as the cleaning agent. Mr. Kenney used a renovator with a slot about 12 in. long and 3/16 in. wide, attached to a metal tube which served as a handle, I FIG. AIR COMPRESSORS ARRANGED FOR OPERATION AS VACUUM PUMPS. and to a ^-m. diameter hose and larger pipe line leading to separators and vacuum pump. Mr. Kenney 's first renovator is illustrated in Fig. 5. Mr. Kenney used as vacuum pumps commercial air com- pressors, the first of which was installed in the Frick Building in 1902 and is illustrated in Fig. 6. Later he adapted the Clay- 12 VACUUM CLEANING SYSTEMS ton air compressor, with mechanically-operated induction and poppet eduction valves on larger sizes, and single mechanically- operated induction and eduction valves on the smaller sizes. The separators used by Mr. Kenney differed from those used by the Sanitary Devices Manufacturing Company in that they contained several interior partitions, screens, and baffles, and FIG. 7. SEPARATORS INSTALLED BY MR. KENNEY IN FRICK BUILDING. the air was drawn directly through the body of water in the wet separator. The relative merits of these types of separators will be discussed in a later chapter. The separators installed by Mr. Kenney in the Frick Build- ing, and which are practically the same as were used by him HISTORY OF MECHANICAL CLEANING 13 as long as he manufactured vacuum cleaning apparatus, are illustrated in Fig. 7. After his application had been in the patent office for about six years he was granted a fundamental patent on a vacuum cleaning system. Renovator with Inrush Slot. The Sanitary Devices Manu- facturing Company then produced a carpet renovator using vacuum only as . a cleaning agent. This cleaner has a wider cleaning slot that the cleaners usually furnished by Mr. Kenney, about 5/16 in. wide, with a supplemental slot or vacuum breaker opening out of the top of the renovator and separated from the cleaning slot by a narrow partition extending nearly to the -25 -Pile of Carpet ^Back of 'Carpet Floor FIG. 8. VACUUM RENOVATOR WITH INRUSH SLOT, INTRODUCED BY THE SANITARY DEVICES MANUFACTURING CO. carpet, as illustrated in Fig. 8. The relative merits of these types of renovators will be discussed in a later chapter. Shortly after the introduction of vacuum cleaning by Mr. Kenney and the Sanitary Devices Manufacturing Company, the American Air Cleaning Company published an interesting little booklet entitled, "Compressed Air Versus Vacuum," which set forth in great detail the so-called advantages of compressed air over vacuum as a medium of mechanical carpet cleaning, and, apparently, proved that vacuum cleaners were much less effi- cient than cleaners operated by compressed air. A year or two later the American Air Cleaning Company evidently had a change of heart and began to manufacture these same "in- 14 VACUUM CLEANING SYSTEMS efficient" vacuum cleaners. Their previous treatise on vacuum cleaning, which apparently was not copyrighted, was repub- lished by both the Sanitary Devices Manufacturing Company and by the Vacuum Cleaner Company, which had acquired Mr. Kenney's patents, and freely distributed. Thus this little work of the Milwaukee company, instead of injuring their competitors, was turned into good advertising for them and required a lot of explanation from the Milwaukee company. Steam Aspirators Used as Vacuum Producers. The Amer- ican Air Cleaning Company used a steam aspirator as its vacuum producer and, unlike its predecessor, the air-operated ejector, it made good and has also been used to a limited extent by the Sanitary Devices Manufacturing Company. It is now marketed by the Richmond Radiator Company, and its merits will be discussed in a later chapter. The American Air Cleaner Company also used as a vacuum producer the single-impeller type of rota.ry pump, made by the Garden City Engineering Company, which was also later adopted, to a limited extent, by the Vacuum Cleaner Company. This will be discussed further on. The renovator used by this company was a single-slot type, with %-in. by 10-in. cleaning slot. These systems at once be- came notable on account of the small size of the vacuum pro- ducers used, the low degree of vacuum carried, and the vigorous campaign of advertising which was conducted. Several firms soon began to market vacuum cleaning systems almost identical with that of Mr. Kenney, among which were the Blaisdell Machinery Company, The Baldwin Engineering Company, and The General Compressed Air and Vacuum Machinery Company, the latter being the original Thurman company. The Vacuum Cleaner Company then began a series of in- fringment suits against nearly every manufacturer of vacuum cleaning systems. In nearly every case the suit has resulted in the offending company paying license fees to the Vacuum Cleaner Company, and this concern has now abandoned the manufacture of vacuum cleaners and has become a licensing company. At this writing nearly twenty firms are paying HISTORY OF MECHANICAL CLEANING 15 license fees to the Vacuum Cleaner Company and there is one suit now in the courts. Piston Pump Used Without Separators. A vacuum clean- ing system of somewhat different design was produced by two former employees of the Vacuum Cleaner Company, Mr. Dunn, the once well-known " Farmer Dunn" of the weather bureau, afterward salesman for the Vacuum Cleaner Company, and Mr. Locke, at one time this firm's engineer. This company was first known as the Vacuum Cleaning Company, and, shortly afterward, as the Dunn-Locke Vacuum Cleaning Company. No separators were used with this system, but the dust-laden air was led from the pipe lines directly into a chamber on the pump, known as the ''saturation chamber," and there mingled with a stream of water converting the dust into a thin mud. The air, water and mud then passed through the pump, the muddy water was discharged into the sewer, and the air into the atmosphere. The vacuum producer used was a piston pump without suction valves. With this system it was possible to handle water in almost unlimited quantities and with this fea- ture a system of mechanical scrubbing was attempted for which great claims were made, none of which, however, were realized in a commercial way. These gentlemen sold their patents to the E. H. Wheeler Company, which attempted to market the system in its original form. It was found, however, that the piston pump was not adapted to the handling of grit which was picked up by the renovators, and a rotary pump, with single impeller and a fol- lower was substituted. This system is now marketed by the Vacuum Engineering Company, of New York, and is known as the Eotrex system. Mr. Dunn again entered the field of vacuum cleaning and began marketing his machine a short time ago with a new form of 'automatic separator discharging to sewer. First Portable Vacuum Cleaner. About 1905, Dr. William Noe ? of San Francisco, constructed the first portable vacuum cleaner. This machine contained a mechanically-driven rotary brush, similar to the brushes used in the familiar carpet sweeper, for loosening the dust from the carpet. This dust was sucked up by a two-stage turbine fan and discharged into a dust bag, 16 VACUUM CLEANING SYSTEMS mounted on the handle, similar to the bags on the compressed air cleaners. The whole machine was mounted on wheels and provided with a small direct-connected motor. This machine is illustrated in Fig. 9 and is the original form of the well-known Invincible renovator manufactured by the Electric Renovator Company, of Pittsburgh. This company now produces a com- plete line of stationary and portable vacuum cleaners, all of which use multi-stage turbines. The sale of the product of this company, until recently, was controlled by the United States Radiator Corporation. FIG. 9. FIRST PORTABLE VACUUM CLEANER, CONSTRUCTED BY DR. WILLIAM NOE, OF SAN FRANCISCO, IN 1905. First Use of Stationary Multi-Stage Turbine Blowers. About 1905 Mr. Ira Spencer, president and engineer of the Organ Power Company, which manufactured a multi-stage tur- bine blower for organs, known as the "Orgoblow," organized the Spencer Turbine Cleaner Company and marketed a vacuum cleaning system, using a modification of the "Orgoblow" as a vacuum producer. These machines were first constructed with/ HISTORY OF MECHANICAL CLEANING 17 sheet metal casings and had sheet steel fans, with wings riveted on and mounted on horizontal shafts. The separators were sheet metal receptacles with screens for catching litter. Light-weight hose, 2 in. in diameter, was used to connect the renovators to 4-in. sheet metal pipe lines. A variety of renovators was pro- duced for use with this system. Carpet renovators having - J/ "Square FIG. 10. LATE TYPE OP SPENCER VACUUM CLEANING MACHINE, OPERATED BY MULTI-STAGE TURBINE BLOWER. cleaning slots varying from 10 in. by ^4 in. to 20 in. by l /^ in. were used, and a very complete line of swivel joints for con- necting the renovators and the hose to the handles was de- veloped. This system was operated at 5 in. vacuum, which was much lower than that used by any other system, 15 in. being standard at that time, and a much larger volume of air was 18 VACUUM CLEANING SYSTEMS exhausted under certain conditions than was possible with any of the then existing systems. Owing to the large volume of air exhausted and to the large size of the renovators, hose and pipe lines, larger articles could be picked up than was possible with any of the existing systems. A great deal of weight was attached to this condition by the manufacturers, a favorite stunt being to pick up nails, washers, waste, small pieces of paper and even pea coal from a floor and finally to pick up a quantity of flour which had first been carefully arranged for the demonstration. This invasion of the vacuum cleaning field was considered by the established manufacturers as a freak and the apparatus was christened "the tin machine." Whenever it was in- stalled in competition with other forms of cleaning systems, the daily question asked by its competitors was, "Has the tin machine fallen apart?" However, the tin machine did not fall apart, but held its own with the other systems, even in its crude and inefficient state. Finding that the construction he had adopted was too flimsy and subject to abnormal leakage, Mr. Spencer developed a new form of machine, using cast-iron casing and welded fan wheels and adopted standard pipe and fittings. He also brought out a line of sheet metal tools and on the whole perfected a satisfactory cleaning system. One of his machines of a later type is illustrated in Fig. 10. Separators Emptying to Sewer by Air Pressure. A new form of vacuum cleaning system was introduced by Mr. Moor- head, of San Francisco, who used an inrush type of renovator having an inlet for air on each side of the cleaning slot. The separator used with this system was a wet separator and contained a screen cleaned by a rotary brush into which all the dust contained in the air lodged. The pump used with this system was generally of the piston type, fitted with a single rotary valve, so connected to the valve stem that it could be rotated thereon and the machine changed from a vacuum pump to an air compressor in order that the contents of the separators might be discharged into the sewer by air pressure when it was desired to empty same. This system was marketed by the Sanitary Dust Removal Company, of San Francisco, and, later, was taken over by the American Rotary Valve Company, of Chicago, which is now HISTORY OF MECHANICAL CLEANING 19 marketing same. It eliminates the manual handling of the dust at any stage of its removal, a feature which is made much of by its manufacturers, but one which is likely to cause some trouble for the sewerage system if care is not exercised. Machines Using Root Blowers as Vacuum Producers. The use of a Root type of rotary pump as a vacuum producer was first undertaken by the Foster and Glidden Engineering Company, of Buffalo, which marketed the Acme system about 1907, the same company having previously built a simliar sys- tem for the removal of grain from steam barges. The other features of this system did not differ materially from those already on the market. Being familiar with the various uses to which this type of vacuum pump had been adapted, the principal one being the operation of pneumatic tube systems, the author suggested the use of this type of vacuum producer about two years previous to its introduction and was advised by one manufacturer that such a type of pump was not suitable for vacuum cleaning. The fallacy of this statement will be brought out in detail in a later chapter. The type of vacuum producer just described has been adopted in many makes of vacuum cleaners, including the Hope, Con- nellsville, Arco, and, lately, in the American Rotary Valve Company's smaller systems. During the past four years a score or more of new stationary vacuum cleaning systems have been introduced, among which are the Palm, a modification of the Dunn-Locke system; the Tuec, a turbine cleaner; the Water Witch, which uses a water- operated turbine as a vacuum producer, and the Hydraulic, with water-operated ejector. At the same time a hundred or more portable vacuum cleaners have been marketed. These are of almost every conceivable type and form and are operated by hand, electricity, and water power. Among them will be found machines which are good, bad and indifferent, the effi- ciency and economy of which will be discussed in a later chapter. This nearly universal invasion of the vacuum cleaner field by anybody and everybody looking for a good selling article, establishes the fact that the vacuum cleaner is not a fad or fancy, but has become almost a household necessity and has led 20 VACUUM CLEANING SYSTEMS large corporations to take it up as a branch of their business. First, the Sanitary Devices Manufacturing Company and the Vacuum Cleaner Company, the pioneers in the field, after a legal battle of years, consolidated with a view of driving their competitors from the field as infringers of the patents con- trolled by the two organizations. The result of this was the licensing of other companies. In an attempt to control the sale of their type of apparatus notice was served on all users of other types of vacuum cleaners that they were liable to prose- cution for using infringing apparatus. Later, the McCrum-Howell Company, a manufacturer of heating boilers and radiators, secured control of the products of the American Air Cleaning Company and the Vacuum Clean- er Company and sold these machines to the trade for installa- tion by the plumbers and steam fitters. The McCrum-Howell Company has been succeeded by the Richmond Radiator Com- pany, which is handling these vacuum cleaning machines. Shortly afterwards, the United States Radiator Corporation secured control of the Invincible and the Connellsville systems, and, lastly, the American Radiator Company secured the Wand system. Thus we see that vacuum cleaning seems to be virtually in the control of the manufacturers of heating apparatus, who are also among the largest corporations in this country and well able to control the future of this business to their liking. As to the future of vacuum cleaning the author considers that it is at present, like the automobile, at the height of its career, and also, like the automobile, that it is a useful appliance to mankind and that it has its proper place as a part of the mechanical equipment of our modern buildings. As to the type of vacuum cleaner of the future, the author believes that these appliances will become standardized, just as all other useful appliances have been, and that the form that it will then take will be a survival of the fittest. What that form may resemble the reader may more readily judge when he has completed the reading of this book. CHAPTER II. REQUIREMENTS OF AN IDEAL VACUUM CLEANING SYSTEM. Before a comparison of the relative merits of any line of appliances, used for any one purpose, can be intelligently made, one must have either some form of that apparatus which we consider as a standard for comparison that we may rate all others as inferior or superior thereto, or else an ideal of a perfect system must be assumed, and the measures with which each of the various appliances approaches the requirements of the ideal will establish their relative merits. The author has elected to use the latter method in comparing the various systems of vacuum cleaning, and it is necessary, therefore, to first determine what are the requirements we shall impose on the ideal system. An ideal vacuum cleaning system would be one which, when installed in any building, will displace all appliances used for dry cleaning in the semi-annual renovating or house cleaning, the weekly cleaning or Friday sweeping and the daily supple- mental cleaning. If our system be truly an ideal one, the premises should never become so dirty as to require any semi- annual cleaning at all, and, if the daily cleaning be anyway thorough, there need be no weekly cleaning. This latter con- dition may be governed by the will of the housekeeper or janitor. The compressed air cleaners first introduced were intended for use only at the semi-annual cleaning and they were in reality carpet renovators, which were assumed as imparting to the carpets all the beneficial results that could be obtained by taking them up and sending them to a carpet-cleaning estab- lishment, with the advantage over this latter method, that the labor of removal and replacement of the carpets was rendered unnecessary, but with the disadvantage that all the germ-laden 21 22 VACUUM CLEANING SYSTEMS air, used as a means of cleaning the carpets, was blown back into the apartment, leaving the germs in their former abode. This disadvantage, however, is partly offset by the fact that while the majority of the grms in one's own carpet are blown out at the carpet cleaners, a mixed company of germs from your neighbors' and others' carpets, which may be in the tumbling barrel at the same time with your own, are returned to you with your carpet. Neither of these conditions is ideal and we will expect our ideal cleaner to completely remove from the premises, not only the dust and dirt, but also the germ-laden air which is used as a means of conveying this dirt. For replacing the weekly and the daily cleaning, these earlier renovators were not suitable, as in order to use same the fur- niture must all be removed from the apartment. To accomplish this daily and weekly cleaning, the ideal vacuum cleaner must replace the broom and dust pan, and their inseparable companion, the duster, and must also super- sede that time-honored mechanical cleaner, the carpet sweeper. The reader will doubtless consider that in making this state- ment the author is asking the vacuum cleaner to perform much more than it is usually called on to do. However, we are now discussing an ideal system, and the above requirements are not absolutely beyond what can be accomplished by some of the cleaning systems now on the market. To accomplish this requirement the ideal cleaner must pick up everything likely to be found on the floor which cannot be readily picked up by hand. The character of this material will vary greatly according to the uses of 'the apartment cleaned. In residences and offices, where carpets or rugs are in use, cigar stumps and matches are usually deposited in cuspidors and small pieces of paper in waste baskets, consequently there should be nothing but dust to be removed from a residence and, perhaps, mud and sand from the shoes of the many visitors, in addition to the dust in an office. However, there are special conditions likely to be met in many cases ; sewing rooms will be littered with basting threads and scraps of cloth; department stores, with a great quantity of pins; banking rooms with bands and large-sized bank pins; all REQUIREMENTS OF AN IDEAL SYSTEM 23 of which increase the requirements of the ideal system. A cleaner which is perfectly adapted to one sort of apartment will be entirely unsuited for another, and the ideal cleaner will be one which can be readily adapted to all conditions likely to be met in the building in which it is installed. The ideal cleaner must be able to accomplish the above stated requirements without the necessity of moving heavy pieces of furniture out of or about the apartment; that is, it must be capable of being efficiently operated under beds, tables and chairs, around the legs of other heavy furniture, behind book- cases, pianos, cabinets, etc., over curtains, draperies and hang- ings, over walls, behind pictures and over mouldings and carved ornaments, all without injury to any of the furniture or fittings of the apartment, and with the least expenditure of energy by the operator. These conditions should be met with the fewest possible num- ber of cleaning appliances, none of which should be provided with small attachments liable to be lost or misplaced, and all parts of the system, which must necessarily be moved about, either before, after or during the cleaning operation, should be of minimum weight and bulk, but of rugged and lasting con- struction. The ideal vacuum cleaner should be of such proportions and provided with ample motive power to clean rapidly and effectively. For use in an office building the cleaner should be able to thoroughly clean an average-sized office, including floor, walls, furniture and fittings in from 10 to 15 minutes, and for resi- dence work, should be of sufficient capacity to clean an apart- ment, including floor, walls, curtains, draperies, pictures and furniture in not exceeding 30 minutes. The ideal system should be so arranged that any apart- ment in the building can be cleaned with the least possible disturbance and without affecting the use of any other apart^ ment, excepting perhaps, the corridors or hallways. In large offices, drafting rooms and similar apartments, it may become necessary to clean same while they are occupied; therefore, our ideal system must be practically' noiseless in operation and must offer the least possible obstruction to the proper use of the room by its regular occupants. 24 'VACUUM CLEANING SYSTEMS Necessity and Proper Location of Stationary Parts. To be of sufficient power to do rapid cleaning and in order to remove from the building all dust and germ-laden air, the cleaning system must necessarily contain some stationary parts. The motive power can generally be confined to these stationary parts, and must, in such cases, be located within the building to be cleaned. Therefore, it should operate with the minimum of noise and vibration. Machines located in office or other large buildings, containing elevators or other complicated apparatus requiring skilled at- tendance, which are provided with complicated control and with other attachments, are not objectionable, and in such cases simplicity should give way to efficiency, but unnecessary complications should be avoided. In residences and other small buildings, where the vacuum cleaner is likely to be the only machinery installed, the sys- tem must be one which requires the minimum attention and must be capable of being started and stopped by any person of average ability, without the necessity of going to the point where the machine is located. The power consumption of the ideal system should be a minimum to accomplish satisfactory results and should be, as nearly as possible, directly proportioned to the amount of clean- ing being done. This requirement is most important in hotels, where some cleaning is likely to be done at all hours, day and night. In other words, vacuum must be "on tap" and as readily attainable at any point in the building as your water or electric light. In office buildings, where a schedule of clean- ing hours is fixed, and in residences where cleaning hours are few and the capacity of the plant is rarely more than could be attended to by one operator, this requirement is not of as great importance. Lastly, our ideal system, from the standpoint of the pur- chaser, must be of such rugged construction, as will enable it to operate efficiently for, at least, ten years and its mechanical details such that it will operate continuously, without expert attention, and that the annual expense for repairs during the life of the machine will not exceed 5% of the first cost of the system. CHAPTER III. THE CARPET RENOVATOR. In undertaking the comparison of a number of different makes of any appliance, in order to determine the good and bad points in each, where the apparatus is composed of a number of separate and distinct parts, each having its proper function, which they must perform in order to make the whole apparatus effective, as in a vacuum cleaning system, it becomes necessary to isolate temporarily each part and consider its action, first, as a unit working under the most favorable con- ditions, and, second, as a component part of the whole ap- paratus in order to determine where the weak points in any system occur and what modifications are necessary in the vari- ous parts of the apparatus to make some vital part of the whole more effective. It is further necessary to determine what are the vital parts of the system in order that the other parts may be accommodated to the effective action of that part. Four Important Parts of Vacuum Cleaning System. In analyzing a vacuum cleaning system it naturally divides itself into four parts, viz. : the cleaning tool or renovator, the air- conveying system or hose and pipe lines, the separators or other means of disposal of the material picked up, and the vacuum producer. The author considers that the renovator is the most impor- tant part of the system and that the other parts should be made of such proportions and with such physical characteristics as will produce the proper conditions at the renovator to permit it to perform its functions in the most effective manner. As the vacuum cleaning system must be capable of cleaning surfaces of a widely variable character many forms of reno- vators are necessary. Of the various surfaces cleaned the author considers that carpets and rugs comprise the most im- 25 26 VACUUM CLEANING SYSTEMS portant, as well as the most difficult to clean effectively, so that the carpet renovator will be considered first. The Straight Vacuum Tool. Various forms of carpet ren- ovators have been and are in use by manufacturers of vacuum cleaning systems. The first type of renovator to be considered is that having a cleaning slot not over 12 in. long, with its edges parellel throughout its length, and not over ^ in. wide, with a face in contact with the carpet not over ^ in. wide on each side of the slot. This form of renovator is illustrated in Fig. 11 and is designated by the writer as Type A. The first FIG. 12. TYPE B, WITH WIDE FIG. 11. TYPE A, THE STRAIGHT SLOT AND WIDE BEARING VACUUM TOOL. SURFACE. of these renovators was introduced by Mr. Kenney and, as finally adopted by him, was 12^ in. long, with %-in. face and with a cleaning slot 11^2 in. long and 5/32 in. wide. This form of cleaner was termed the "straight vacuum tool" and is used today by many manufacturers. Slight modifications in its form and dimensions were made in some cases, as in the one manu- factured by the American Air Cleaning Company. In the one used in all tests by the writer on type A renovators, the slot was reduced to 10 in. long and % in. wide and the face of the renovator was slightly rounded at the outer edges, leaving very little surface in contact with the carpet. . : A renovator of this type is easily operated over any carpet even when a considerable degree of vacuum exists within the renovator itself. It has met with favor when used with the piston type of vacuum pump without vacuum control, as was the case with the earlier systems. However, when a very high THE CARPET RENOVATOR* 27 degree of vacuum occurs within the renovator it has a tendency to pull the nap from the pile of the carpet. Soon after the introduction of this form of renovator, some users of same, particularly in San Francisco, complained that while the renovator effectively removed the dust from carpets it failed to pick up matches and other small articles and pre- liminary or subsequent cleaning was necessary in order to remove such litter. To overcome this difficulty Mr. Kenney increased the width of the cleaning slot to nearly y^ in., with the result that when a high degree of vacuum existed within the renovator, which often occurred where no vacuum control was used, it stuck to the carpet, rendering its operation difficult and, at the same time, doing great damage to the carpet. Hence, its use with the piston type of vacuum pumps was abandoned. Mr. Kenney then modified this wide slot renovator by making the face of same much wider, thus having more surface in contact with the carpet on each side of the slot, preventing the renovator from sinking into the nap of the carpet. This type of renovator is illustrated in Fig. 12 and has been designated as Type B. While not as destructive to the carpets, when a high degree of vacuum existed under the same, it still pushed hard and was not as rapid a cleaner as the narrow-lipped Type A renovator. Renovator with Auxiliary Slot Open to Atmosphere. The renovator introduced by the Sanitary Devices Manufac- turing Company differed widely from the former types in that it was provided with an auxiliary slot, open to the atmos- phere through the top of the renovator, which communicated with the slot open to the vacuum by a space of 1/32-in. under the partition separating the slots. The cleaning slot was made 5/16-in. wide and the face of the renovator was made 2-in. wide, which gave a contact of 13/32-in. in front of the inrush slot and 21/32-in. in the rear of the cleaning slot. This form of renovator is illustrated in Fig. 13 and is designated as Type C. The auxiliary slot or vacuum breaker permitted air to enter the cleaning slot even when the renovator was placed on a surface plate, and, owing to this feature, a high degree of vacuum never existed within the renovator. It was always 28 VACUUM CLEANING SYSTEMS easy to operate and did not damage the carpet. Owing to the wide slot, articles of considerable size could be picked up, and there was always an abundance of air passing through the renovator to produce a velocity in the hose and pipe lines sufficient to carry any heavy articles picked up. The vacuum producer, control apparatus and the proportions of the hose and piping used at that time made the degree of vacuum in the renovator a function of the quantity of air passing, with wide limits of variation under existing conditions, and this form of renovator is practically the only one which will do effective cleaning, including the picking up of litter, without undue wear on carpets, when used with a system having the above-stated characteristics. This renovator, how- ever is not without its faults. Owing to the wide surface in contact with the carpet, a considerable degree of vacuum is necessary in order that any air shall enter the renovator under FIG. 13. TYPE C, WITH AUX- ILIARY SLOT, OPEN TO ATMOSPHERE. FIG. 14. TYPE D, WITH TWO CLEANING SLOTS. the faces of same and, as the air entering the inrush slot pre- vents the formation of such vacuum within the renovator, very little air enters the renovator between itsi face and the carpet. When the renovator is operated on a carpet having a glue-sized back, no air enters through the carpet, therefore all air entering the renovator must come through the inrush slot and under the partition separating same from the cleaning slot. Under these conditions only one side of the vacuum slot is effective and this effective side is raised above the surface of the carpet. When operated on an ingrain or other loose-fabric carpet, much air enters through the fabric of the carpet, due to the THE CARPET RENOVATOR 29 wide cleaning and inrush slots, in addition to the quantity of air entering through the inrush slot, making this renovator, when operating under these conditions, use an unnecessary amount of air. Apparently, this renovator has been designed to prevent the formation of any great degree of vacuum under same and such a design has resulted in a greater volume of air at a lower vacuum passing through than through renovators of other types. . This property of the renovator raises the question whether the quantity of air or the degree of vacuum in the renovator is most essential for the removal of dirt from carpets. Tests made by Mr. S. A. Reeve, consulting engineer for the Vacuum Cleaner Company, with this type of renovator, with the in- rush open and repeated with the inrush closed, disclose the fact that it does more effective cleaning with its inrush closed, while the volume of 2 in. x 5/32 in. THE CARPET RENOVATOR 45 Curve A was made with the angle of the handle such as would give as near as possible a perfect contact of the sweeper with the carpet. Curve B was made with the sweeper handle canted 5 below the proper angle. Curve C was made with the sweeper handle raised approximately 15 above the proper angle. The ordinates represented the amount of dust in the carpet in 40ths of a pound, also reduced by the author to ounces, and the abscissae the number of strokes made by the sweeper. 5 10 FIG. 20. ZO 30 40 50 60 Number of Strokes o-f Sweeper THREE SERIES OF TESTS WITH KENNEY TYPE A RENOVATORS. Curves B and C show the loss in efficiency which occurs when the renovator is canted from its proper position on the carpet. This falling off in efficiency will necessarily be greater the wider the face of the renovator, as is shown in further tests by Mr. Reeve, using a Type C renovator, which tests also show that this renovator gives a slightly higher efficiency when operated with the inrush slot stopped, as is shown in Fig. 21. 46 VACUUM CLEANING SYSTEMS In this curve the ordinates represent the per cent, of normal dirt, i. e., the amount likely to be found in a dirty carpet, re- maining in the carpet at any stage of the cleaning, and the abscissae the number of strokes that have been made by the sweeper. Heavy solid lines represent the results with the inrush open and dotted lines the results with the inrush stopped. The figures on the curve represent the degree to which the handle has been varied from the position giving the best results in cleaning. is 20 n Number of JrtroKes of Sweeper PIG. 21. TESTS BY MR. REEVE, USING TYPE C RENOVATOR. Fig. 22 shows the results of tests by Mr. Reeve using a reno- vator of Type D, -having a double cleaning slot, and indicate that this type of cleaner is not as efficient as Type A and is affected more by the canting of the handle from the best angle for cleaning. The above mentioned tests are published through the courtesy of Messrs. Ewing and Ewing, attorneys for the Vacuum Clean- er Company. Since the method of making these tests is entirely different from that used by the author, a comparison of the results, with any assurance that the same conditions existed in both cases, is impossible. It occurred to the author that a comparison of the results of the tests by Mr. Reeve, using a carpet artificially filled with actual dirt taken from carpets, with the tests made by the author on carpets naturally soiled, would tend to show if equal results could be obtained by a vacuum cleaner by artificially soiling a carpet with dirt taken from another car- pet, and in cleaning a carpet naturally soiled. THE CARPET RENOVATOR 47 The author has reduced these results to the same units of time per square yard of carpet cleaned as in the test on the Philadelphia carpet with the small-sized Type A renovator (11-in. x 5/2 -in. face and 10-in. x 3/16-in. cleaning slot). The carpet used by the author contained 6 sq. yds. and was held in cleaning by a weight at each corner, while the carpet used by Mr. Reeve was y<\ yd. wide and cleaned for approximately one yard of its length, the relative size being 1 to 8. The time of cleaning was 6 min. in the author's test which would corre- Orictinal Weight ofGarpef B 10 FIG. 22. 50 40 50 60 70 N u m be r of St ro ke s of Sweeper TESTS BY MR. REE~VE, USING TYPE D RENOVATOR. spond to 24-min. cleaning in Mr. Reeve's test, or 30 strokes of the sweeper. The total dust in the carpet in Mr. Reeve's test was 5/40 Ibs., or 2.66 oz. per square yard, and his test is compared with the author's test with the carpet containing 2 oz. per square yard. Calculation of the per cent, of total 48 VACUUM CLEANING SYSTEMS dirt removed in each 5 strokes of the sweeper in Mr. Reeve's test, and a comparison of the per cent, of dirt removed in each one minute's test by the author are given below: TABLE 4. COMPARISON OF TESTS MADE BY MR. REEVE AND BY THE AUTHOR. MR. REEVE'S TEST. AUTHOR'S TEST. Strokes. Material per cent removed, . of total. Minutes. Material removed, per cent, of total. S 10 15 20 25 30 62 80 89 94 97 99 1 2 3 4 5 6 60 81 90 95 98 100 The above comparison was made using curve A, Fig. 20, with the sweeper at its best angle with the floor. The close agreement of the two tests indicates that a carpet artificially soiled with dirt actually removed from another carpet by a vacuum cleaner is as difficult to remove as dirt which has been worked into a carpet by ordinary daily use. This condition does not result when any other substance is used to artificially soil the carpet, as will readily be seen by reference to the tests of carpets filled with sand and other substances which have been described in this chapter. A comparative test of three different renovators was recently made by the author. Renovator No. 1 had a cleaning slot 14 in. long by ^4 in. wide, the edges of the slot being a seg- ment of a circle having a >6-in. radius. This form of cleaning surface allows very small area of contact with the surface cleaned and permits the admission of large air volumes, about 56 cu. ft., with 2-in. vacuum. It is practically a Type F reno- vator, similar to that used in the tests at Hartford. Renovator No. 2 had a cleaning slot 9y 2 in. long and l / in. wide, the face of the renovator being approximately % in. wide and practically a plain surface, a typical Type B reno- vator. Renovator No. 3 had a cleaning slot 7% in. long and l /% in. THE CARPET RENOVATOR 49 wide, the face of the renovator being % in. wide and the edges slightly rounded, a typical Type A renovator. The carpet used was a Colonial velvet rug with %-iu. nap, closely woven, containing 6 sq. yds. This rug was filled with 12 oz. of dirt taken from separators of cleaning machines, from which the lint and litter had been screened. This was rubbed into the carpet until no dirt was visible on the surface, the surface being then lightly swept with a brush and weighed. In cleaning this carpet the renovator was passed once over the entire surface at the rate of about 70 ft. per minute. This required six strokes and 50 seconds for No. 1 cleaner, nine strokes and 77 seconds for No. 2 cleaner, and 12 strokes and 100 seconds for No. 3 cleaner. The carpet was then weighed, spread down and gone over three times, weighed, spread down and gone over four times. This operation was repeated until the carpet came within y 2 oz. of its weight when received. Each of the three renovators was operated with a vacuum of 2 in. at the renovator. The results of these tests are illustrated by curves 1A, 2A and 3A in Fig. 23. This shows that to remove 95% of the dirt the renovator had to be passed over the carpet 20 times for No. 1 renovator, 15 times for No. 2 renovator aijd 8 times for No. 3 renovator. Similar tests were then made with each of the renovators, with a vacuum of 4.5 in. of mercury at the renovator. The results are shown by curves IB, 2B and 3B (Fig. 23) These show that to remove 95% of the dirt the renovator had to be passed over the carpet 11 times with No. 1 renovator, 6^2 times with No. 2> and 4^ times with No. 3. These tests are all on the same carpet, with the same quan- tity of the same dirt and with the renovators moved at the same speed in each case. The comparison of the results should give a fair indication of the efficiency of the different types of renovators at different degrees of vacuum within the reno- vator and, therefore, form the most conclusive proof of the statements relative to the efficiency of renovators as given in this chapter. All cleaning tests that the author has observed indicate that 50 VACUUM CLEANING SYSTEMS the higher the vacuum within the renovator the more rapid and effective the cleaning, and that the efficiency of the reno- vator is fully as high with a small as with a large volume of air passing through the renovator and with the same degree of vacuum within same. Therefore, the most effective and eco- 2 4 and adds to its first cost, and as cleaning of this char- acter is required only at rare intervals, these renovators may also be considered as special and need not be included in the average equipment. The author considers that the renovator equipment for a sys- tem in which from 20 to 30 cu. ft. of air per minute is ex- hausted for each renovator in operation, and which the author classes as a " small volume" system, should contain the follow- ing renovators in each "set" furnished: One carpet renovator with cleaning slot y^ in. by 12 in. long. One bare floor renovator 12 in. long, with curved felt- covered face. One wall renovator 12 in. long, with cotton flannel and curved face. One upholstery renovator with slot ^4 i n - by 4 in. One corner cleaner. One radiator cleaner. In addition, one or more hat brushes should be included with each installation. The renovator equipment for a system in which 70 cu. ft. of air per minute is exhausted for each renovator in operation, which the author classes as a "large volume" system, should contain the following renovators in each "set" furnished: One carpet renovator, with slot ^4 i n - by 15 in. One bare floor renovator 15 in. long, with curved felt-cov- ered face. One wall brush, with skirted bristles 12 in. long and 2 in. wide. One hand brush, with hose connection at end, 8 in. long and 2 in. wide. One 4-in. round brush for relief work. One upholstery renovator. One corner cleaner. One radiator tool. At least one hat brush with each system. The number of sets of renovators to be furnished should naturally be at least equal to the number of sweepers which 68 VACUUM CLEANING SYSTEMS the plant will handle, and in all buildings, except residences, there should be one set of renovators for each floor of the building. This will be ample, except in exceedingly large buildings. The wearing face of any renovator should never be made of soft metal, such as brass or aluminum, as the action of the dust passing the face of the renovator, where the velocity is always the highest in the system, will roughen these parts and cause undue wear on the surfaces cleaned. Stamped steel is undoubtedly the best material for wearing surface and cast- iron ranks next. These are the only materials which should be permitted. CHAPTER V. STEMS AND HANDLES. Having discussed the various forms of renovators in detail, the next appliance to be taken up is the connection between the renovator and the cleaning hose, this being the next por- tion of the apparatus forming a conduit for the dust-laden air on its way from the renovator to the atmosphere on the exhaust side of the vacuum producer. In order that the renovator may be moved about on the surfaces to be cleaned, a rigid handle must be provided and, in order -that these various surfaces may be reached while the operator remains in a standing position, it is necessary that this handle be of considerable, as well as variable, length. Also, a passage for the dust-laden air must be provided in connection with this handle. These conditions are best met by a metal , tube, which the author terms the stem. These stems have been made of various metals, that first used being draw^i brass, probably because it is best suited to be nickel plated. On the earlier systems they were almost in- variably made of No. 16-gauge tubing, %-in. outside diameter, and were bent at their upper end through an angle of nearly 135 in order that the hose would hang from the stem vertically downward, when the stem was held at an angle with the floor of 45. The lower ends of these stems were rigidly attached to the renovator in such a manner as to assume the above-mentioned angle with the floor when the renovator was in the proper position for cleaning. In order to bring the curved portion of the stem hand high, the stem was made approximately 5 ft, long. When operated with Type A carpet renovators, these curved stems were apparently satisfactory. However, when they were used in department stores, and other places where much bare 69 70 VACUUM CLEANING SYSTEMS floor cleaning was necessary, the stems were cut through at the curved portion by the sand blast action of the dust. The cutting of these stems in bare floor work, while they were satis- factory in carpet cleaning, indicates that the velocity in the stem, due to the large volume of air passing the bare floor renovator, was too great for this soft metal to withstand the impact of the dust on the curved surface. With the systems in use at that time no means were provided to control the vacuum at the vacuum producer and the hose and pipe lines were small, both of which tended to cause a wide variation in the volume of air exhausted under various conditions, in the character of surface cleaned, and in the number of reno- vators in use. Therefore, the value of this destructive velocity is not readily obtainable. However, the author considers that, in extreme cases, the quantity of air passing through these stems may have been as high as 55 cu. ft. per minute. As the inside diameter of the stems was 24 i n - the area was 0.44 sq. in., or 0.00328 sq. ft., and the velocity through the stem was nearly 17,000 ft. per minute. With an average air passage of 40 cu. ft. per minute the velocity was 12,200 ft. per minute. Referring to tests of carpet renovators, Chapter III, it will be noted that the maximum volume of air passing through carpet renovators of Type A was 33 cu. ft. per minute, which gives a velocity of 10,000 ft. per minute. Apparently, at this velocity, the cutting action, due to the impact of the dust on the curved surfaces, was not severe. However, the author con- siders that the maximum velocity that should be permitted through these stems is 9,000 ft. per minute. As the dirt picked up must be lifted almost vertically, the velocity in the stem must not become too low or dirt will lodge in the stem. Experiments made by the author indicate that the minimum velocity should be at least 4,000 ft. per minute, in order to insure a clean stem at all times. Shortly after the introduction of vacuum cleaning, the use of drawn-steel tubing for the manufacture of stems for clean- ing tools was standard with one manufacturer and, lately, its use has become almost universal, except in cases where very long stems are necessary, as on wall brushes when cleaning STEMS AND HANDLES 71 very high ceilings. For such work, aluminum stems have been adopted. This harder metal will better withstand the cutting action of the dust and can also be made much thinner and lighter in weight than brass tubing of equal strength. These stems were made from 1 in. outside diameter, No. 21 gauge tubing, having an internal area of 0.68 sq. in., and the author does not know of any cases where these stems have been cut by the impact of the dust. Stems of this metal are recommended by the author for use with all floor renovators and with wall brushes, except in cases where exceedingly long stems are required, when those of drawn aluminum tubing are recommended. For use with Type A renovators, where the minimum air quantity is approximately 22 cu. ft. per minute, the greatest area permissible is :dnro 0.0055 sq. ft., or 0.79 sq. in., equiva- lent to 1-in. diameter. With a maximum air quantity, under proper control, of 39 cu. ft. per minute, the minimum area will be -s-fl-o- = 0.00433 sq. ft, or 0.625 sq. in., equivalent to 0.89 in. diameter, so that a 1-in. outside diameter stem of No. 21 gauge metal, having an inside diameter of 0.932 in., is recommended. For use with a Type F renovator, with a minimum air quan- tity of 44 cu. ft. per minute, the maximum area of the stem will be 4000 = 0.011 sq. ft., or 1.58 sq. in., equivalent to 1.4 in. diameter, while, with a maximum air quantity of 70 cu. ft. per minute, the minimum area will be -^h =0.0077 sq. ft., or 1.11 sq. in., equivalent to 1.18 in. diameter, and a 1^4-in. diameter stem of No. 21 gauge metal, having an inside diam- eter of 1.18 in. is recommended. Tests of Mr. S. A. Reeve, which are discussed in Chapter III, indicate that both edges of the cleaning slot on any reno- vator must be in contact with the surface cleaned in order to do effective cleaning. A renovator which is rigidly connected to its stem can be effectively operated with the stem at but one angle with the surface cleaned, which makes the cleaning under furniture, or on wall at various heights above the floor, impossible. In order to do effective cleaning with any degree 72 VACUUM CLEANING SYSTEMS of speed and comfort to the operator, some form of swivel joint between the renovator and its stem is necessary. These swivels have been made in many forms, one of which consists of two hemispheres connected by a bolt on their axis, as shown in Fig. 37. This form of swivel is unsuited for use under these conditions, as lint, thread and any other small articles picked up will catch on the bolt which lies directly in the path of the dust-laden air current, and its use should be prohibited in all cases. Another form of swivel, which is must better than the last mentioned, is shown in the illustration of the bare floor brush, Fig. 26, Chapter IV, there being no obstruction in the air passage. However, these swivels are composed of moving parts FIG. 37. FORM OF SWIVEL JOINT CONNECTING STEM TO RENOVATOR. which are in contact with the dust-laden air and great care must be taken in their design so that in action dust does not lodge between the wearing surfaces and shortly ruin the swivel. This can be guarded against by making any opening between the parts of the swivel point away from the dust current, as indicated in Fig. 38, in which the direction of the air current is indicated by the arrow. A slightly loose fit between the wearing surfaces will permit a small leakage of air through the joint which will tend to remove any dust which may find its way into the joint. However, it is not considered advisable either to allow very much leakage through the joint, as it re- duces the net efficiency of the system, or to depend much on STEMS AND HANDLES 73 the air current through the joint keeping the wearing sur- faces clean. The swivel indicated in the illustration of the floor brush does not entirely prevent the dust entering same and it permits the movement of the stem in a vertical plane only. On the other hand, a swivel consisting of a 45 elbow, rigidly attached to the stem and turning freely on a horizontal spud, and fastened to the renovator, as shown in Fig. 38, allows a motion of the stem either in a vertical plane, which will cause the renovator to rotate, and enable the operator to pass same around or back of legs of furniture, or a semi-rotary motion may be imparted to the stem, which will permit the renovator FIG. 38. SWIVEL JOINT ARRANGED TO PREVENT DUST LODGING BETWEEN THE WEARING SURFACES. to move forward in a straight line while the angle which the stem makes with the floor will constantly decrease. After a little practice the operator can place a renovator equipped with one of these swivels in almost any position without incon- venience. Illustrations of the possibilities of this form of swivel are presented in Figs. 39 and 40, in which an operator is shown cleaning the treads and risers of a stairway without changing her position, and in Fig. 41, where the operator is cleaning the trim of a door with apparent ease. The author considers that this form of swivel is the only satisfactory joint between the renovator and its stem. It is being rapidly adopted by nearly every manufacturer of vacuum cleaners. 74 VACUUM CLEANING SYSTEMS In operating any renovator it is nearly always drawn back- wards and forwards in front of the operator, across the surface to be cleaned. When the hose is rigidly attached to the upper end of the stem, it becomes necessary to drag at least a por- tion of the cleaning hose along with the renovator when it is moved forward, and to crowd the same back on itself when the renovator is moved backward. This action has a tendency FIG. 39. SWIVEL JOINT IN USE. to kink or snarl the hose about itself and makes the operation of the renovator very awkward, often causing the operator's feet to become entangled in the hose. This action also brings an undue amount of wear on the hose near the end which is attached to the stem, as may be readily noted by inspection of hose used with rigidly-attached stems. This will show that the end of the hose is entirely worn through, while the remainder of the hose is still in serviceable condition. The trouble above stated can be overcome by providing a swivel joint at the point of connection between the hose and STEMS AND HANDLES 75 the stern. A few attempts to use a joint similar to that first described in connection with the renovator and its stem, as illustrated in Fig. 37, have been made, but without much suc- cess, as the bolt through the air passage catches dirt and there is not sufficient freedom of movement between the portions of the swivel. Variations of this form of joint have been made, one of which is provided with a screwed union to join the two FIG. 40. ANOTHER USE OF SWIVEL JOINT, SHOWING POSSI- BILITIES OF THIS FORM. portions, as shown in Fig. 42. This is a much better form than that first described and has been successfully used in connec- tion with heavy 1-in. diameter hose. Care must be exercised that the direction of the flow of air is always in the direction indicated by the arrows in the sketches, as a reversal, if only for a short time, will ruin the joint, due to lodgment of dust in the moving parts. Still another variation in this form of swivel has the two main parts made to fit one within the other and a snap ring is 76 VACUUM CLEANING SYSTEMS placed in a groove in the male portion of the joint, this groove being deep enough to take the entire thickness of the ring. The two parts are then fitted together and the ring snaps out into a corresponding groove in the female portion of the joint, uniting the two parts. This joint gives a fairly free movement FIG. 41. OPERATOR CLEANING TRIM OF DOOR WITH SWIVEL JOINT. to the parts thereof, but has the disadvantage that it cannot be taken apart without breaking one of its parts. A modification of this form of swivel has been made by the manufacturers of the last-described swivel, in which semi- circular grooves have been cut, one on the inside of the female FIG. 42. SWIVEL JOINT, WITH SCREWED UNION. FIG. 43. SWIVEL JOINT HAVING BALL BEARINGS. STEMS AND HANDLES 77 portion and one on the outside of the male portion. Steel balls are forced into this groove, after the parts are assembled, through an opening provided in the edges of the parts. This opening is closed, after the balls are in place, by a small pin, as shown in Fig. 43. The swivel then becomes a ball-bearing FIG. 44. ACTON OF BALL-BEARING SWIVEL JOINT. joint, with a freedom of motion characteristic of such bearings. This joint readily responds to every movement of the stem and keeps the hose hanging vertically downward and always free from kinks. Its action is illustrated in Fig. 44, in which it is being used in connection with a carpet renovator. This joint is considered to be the most efficient on the market. It is protected by a patent controlled by a manufacturer of vacuum cleaners. 78 VACUUM CLEANING SYSTEMS Valves are placed at the upper end of the stems by many manufacturers, to cut off the suction when carrying the reno- vators from room to room, and when it is necessary to stop sweeping to move furniture. These valves have nearly always taken the form of a plug cock with tee or knurled handle. They are useful on large installations, where vacuum control is either inherent in the exhauster or where some means of vacuum con- trol is provided, as a considerable saving of power may be obtained by closing same, as will be explained in a later chap- ter, and to overcome the unpleasant hissing noise caused by the inrush of air into the renovator when same is held off the floor. When the exhauster has a capacity of but one sweeper and when the cleaning is done at times when the building is unoc- cupied, there seems to be little need for this refinement, which has two defects: first, the operators will not close the valves: second, when they have been closed they are only partly opened, as indicated in Fig. 45. When this occurs, the portions of the FIG. 45. ILLUSTRATION OF DEFECTS OF PLUG COCKS. plug, which are shown stippled, are quickly cut away by the sand-blast action of the dust, making it necessary to open the valve a still smaller amount the next time it is operated, cutting off still more of the plug until a new plug is necessary in order to make the valve again operative. A few attempts have been made to overcome these defects by making the valves self-closing and having them so con- structed that when the operator grasps the handle the valve will be forced wide open, on the principle of the pistol grip. These valves will, of course, close whenever the handle is re- leased, and it is impossible to grasp the handle in any degree S^TEMS AND HANDLES 79 of comfort without throwing the valve wide open. However, since the valve is closed by a spring, considerable pressure must be applied to the handle in order to keep it open and it acts similar to the Sandow dumb bell in producing fatigue of the fingers in a short time; they have not come into general use. The use of valves in the renovator handle is considered by the author to be an expense not justified by the gain in economy and they are no longer included in specifications prepared by him. CHAPTER VI. HOSE. The more important steps in the evolution of the modern vacuum cleaning system can each be attributed to a change in the design or construction of some one of its component parts, which, in their former standard design, have acted as a limiting factor governing the form and size of other and more im- portant parts of the system. That part of the early systems which played the most im- portant role as a limiting factor was one for whose production the builder of the system had to look to other manufacturers: namely, the flexible hose connecting the renovator stem to the rigid pipe lines and vacuum producer. The early builders of vacuum cleaning systems naturally adopted a standard article for use as a flexible conduit; that is, the vacuum hose which had been used as suction lines for pumps of various characters. For such use it was not necessary that the hose be moved about to any great extent and, there- fore, its weight was not an important factor and had been sacrificed to strength to withstand collapse and the rough hand- ling to which suction hose is subject. This standard hose was built up of many layers of canvas wound around a rubber tube or lining. A spiral wire was im- bedded between the layers of canvas to prevent collapse and the whole was provided with an outer covering of rubber. Generally five to seven layers of canvas were used and the resulting hose was not highly flexible. When used as a flexible conduit in connection with a vacuum cleaning system it became necessary to constantly move the hose back and forth and around the room to be cleaned. It was also necessary to limit the weight of the hose to that which could be easily handled by one person. This led to the adop- tion of small sizes of the then standard hose, 24-in. diameter being first used, but soon this was abandoned in favor of 1-in. diameter hose weighing nearly 1 Ib. per foot of length, which is the maximum weight that can be conveniently handled by 80 HOSE 81 one person. This size hose has become the standard for all systems maintaining a vacuum at the separators of 10. in of mercury or more. Owing to its lack of flexibility this type of hose is easily kinked and is damaged by the pulling out of such kinks, caus- ing the tubing or lining to become separated from the canvas and to collapse, rendering the hose useless. There is also con- siderable wear at the point of connection to the stems of renovators, where rigid connections are used. The outside of this hose, being rubber, is always liberally covered with soap-stone when it leaves the manufacturer, and when new hose is dragged about over carpets, it frequently soils same to a greater degree than they are cleaned by the reno- vator. W'hen this hose has been in use about twice as long as is necessary to wear off the soap-stone, its appearance becomes far from handsome 'and is not considered to be in keeping with the nickel-plated appliances which are furnished with the cleaning tools. To overcome this objection, an outer braid has been applied generally over the rubber coating, thus adding further to its already great weight. What was perhaps the first type of hose to be produced especially for use with vacuum cleaning systems was that in which the fabric was woven in layers, instead of being wrapped spirally around the central tube or lining. Steam was intro- duced into the lining, vulcanizing the lining and firmly uniting the whole mass. This hose was made 1 in. in diameter, without any metal re-inforcement, and was covered with the usual rub- ber coating and with braid, when ordered. This hose weighed 12 oz. per lineal foot and 1-in. diameter was still the largest that could be easily handled. The first attempt to produce a light-weight hose for use with vacuum cleaning systems was by covering a spiral steel tape with canvas. The air leakage through this hose was found to be so high that its use resulted in loss of efficiency of ,the cleaning plant and it was found necessary to line the hose with rubber. This rubber-lined hose is made in larger sizes than formerly used and 2-in. diameter hose weighs approximately 14 oz. per lineal foot. It is also much more flexible than the 1-in. hose formerly used. The introduction of this type made it possible to use larger 82 VACUUM CLEANING SYSTEMS hose in connection with vacuum cleaning systems and permitted the use of a lower vacuum at the separators, with the same results at the carpet renovator, and a larger quantity of air when using the brushes and other renovators. Without this type of hose the low-vacuum, large-volume systems would be impractical. Another type of hose has been recently introduced in which a wire is woven into the fabric of the hose and the rubber lining vulcanized into place as already described. No outer coating of rubber is used and, therefore, no braid is necessary. This gives a light-weight hose of great flexibility and neat ap- pearance and is undoubtedly the best hose for residence work. It is more costly than the steel tape hose which is recommended for office building and factory use, where appearance is not important. Hose Couplings. The earlier systems used couplings having screw-threaded ground joints, similar to those which were then in use on hose intended to withstand pressure. These couplings FIG. 46. BAYONET TYPE OF HOSE COUPLING, INTRODUCED BY THE AMERICAN AIR CLEANING COMPANY. require considerable time to connect and disconnect and the threads are easily damaged by dragging the hose about. The exposed metal parts of the couplings are liable to scratch fur- niture. To overcome the time required to connect and disconnect the screw-coupling, the American Air Cleaning Company intro- duced the bayonet type of coupling, as illustrated in Fig. 46. This coupling is not readily damaged by rough handling, but it has metal surfaces exposed which will scratch furniture. HOSE 83 Both of these couplings have the disadvantage that the air current in the hose must always be in the same direction and the same end of the hose must always be next to the renovator handle. Both of these features tend to increase the wear on the hose, and the reversal of the air current to re- move stoppages is not possible. The coupling produced by the Sanitary Devices Manufactur- ing Company has a piece of steel tubing fitted into each end of the hose and secured by means of a brass slip-coupler fitting over the tubing. All ends being alike, the reversal of the hose is possible with this form of coupling. However, the metal coupler is liable to mar furniture and sometimes there is trouble with the couplings pulling apart. Much of the hose in use today is provided with "pure gum" ends are vulcanized in place, it is necessary to take the hose of metal tubing is slipped inside of these ends to make a coup- ling. With this arrangement there is no metal exposed to mar flG. 47. ALL RUBBER HOSE COUPLING USED BY THE SPENCER TURBINE CLEANER COMPANY. furniture and the hose lengths are reversible. However, there is some trouble from the couplings pulling apart. Since these ends >are vulcanized in place, it is necessary to take the hose to a rubber repair shop whenever the hose breaks back of the coupling, which occurs frequently when rigidly attached to the 84 VACUUM CLEANING SYSTEMS stem of the renovator. These repair shops are much more numerous than a few years ago and this drawback is not a serious one. Another form of coupling used by the Spencer Turbine Cleaner Company is the all-rubber male and female end, as illustrated in Fig. 47. This has the advantage over the metal- slip couplings and the coupling with pure gum ends in that when it is properly locked it cannot be pulled apart. It is absolutely air tight, which is true of no other coupling. But it does not permit the reversal of the hose and is, therefore, recommended for use only with hose of 1)4 -in. diameter or larger, where there is less liability of stoppage, and where the ball-bearing swivel is used at the connection to the stem, pre- venting excessive wear at this point. The pure gum ends, with the internal-slip coupler, is considered to be the most satisfactory for use in all cases, except as above stated. Hose Friction. Hose friction plays an important part in the action of any vacuum cleaning system. In fact, where 1-in. hose is used, it beeomes a limiting factor in the capacity of the system to perform some kinds of cleaning. There are several tables of hose friction published by the manufacturers of vacuum cleaning systems, all of which appear to have been based on a constant velocity within the hose equal to that which would be obtained if the air were at atmospheric pressure throughout the entire length of the hose. But in practice the air is admitted to the hose from the renovator at a considerably lower absolute pressure of from 25 in. to 27 in. of mercury, and is, therefore, moving at a higher velocity. As the pressure is decreased by the friction loss in the hose, the velocity constantly increases with the expansion of the air. The results of many tests made by the author during the past seven years, with hose ranging from 1-in. to 2-in. diameter and with an entering vacuum ranging from to 7 in. of mer- cury and a friction loss of from 1 in. to 25 in. of mer- cury, indicate a close agreement with the formula given in Prof. William Kent's "Mechanical Engineer's Pocketbook, ' ' which is based on the formula; wL HOSE 85 Q = free air in cubic feet per minute. c = a constant which was determined by D 'Arcy as approxi- mately 60. p=the loss of pressure in pounds per square inch. d = the diameter of pipe in inches. L = the length of pipe in feet. w = the density of the entering air in pounds per cubic foot. Reducing the pressure loss to inches of mercury and using in lieu of w, r which is the ratio of the average absolute pres- sure in the pipe to atmospheric pressure, this formula becomes : 0=3,03 t/^f" . , tj To permit the rapid calculation of the air quantity which can be passed through a hose, the author has prepared the diagram shown in Fig. 48. To use this table, look up the fric- tion loss in the hose in the right hand margin, pass along the horizontal line to the left until it intersects the line inclined at an angle of 45 toward the left, indicating the length of the hose. From this intersection pass vertically to the line in- clined at approximately 30 toward the left, representing the diameter of the hose. The quantity in the left-hand margin, opposite the horizontal passing through this intersection, repre- sents the quantity of air which would pass through this hose in cubic feet at the average density in the hose. To correct this quantity to free air, step off the distance on the vertical line from the bottom of the table, representing the average degree of vacuum in the hose, to its intersection with the curved line near the bottom of table. Transfer this distance vertically downward on the left hand margin from the quantity first read on this margin. The quantity opposite the lower end of this distance will be the cubic feet of free air per minute pass- ing through the hose under these conditions. The line inclined towards the right, which passes through the intersection of lines representing hose diameter, and the hori- zontal line representing the cubic feet of air passing through the hose at actual density in same, shows the actual velocity in the hose in feet per second. For friction loss over 10 in. of mercury, use the figures at the right hand of the lower margin, instead of those in the right hand margin, and pass vertically to the hose diameter. 86 VACUUM CLEANING SYSTEMS Free Air,. Cu. Ff. per. Minute ro ' *9.45 ' ^ f 4" Track *4 STTT" 1 " Ak 4" Track *5 Track *6 3' Track '7 Track "6 c c IL65 with Ij'Hose 14.50 w//? /"Hose FIG. 64. ARRANGEMENT OF PIPING RECOMMENDED AS BEST FOR PASSENGER CAR STORAGE YARD. Such a layout must be at once dismissed as impractical, and some other arrangement must be adapted. The arrangement of piping shown in Fig 64 is considered by the author to be the best that can be devised for this case. With this arrangement the vacuum at the separator must be maintained at 11.50 in. mercury to insure a vacuum of 6 in. mercury at the outlet "x" under the most unfavorable con- ditions, and the maximum variation in vacuum at the inlets will be 3.45 in. mercury when 1^4 -in. hose is used. This will give a maximum vacuum under a carpet renovator of l l / 2 in. mer- 124 VACUUM CLEANING SYSTEMS cury with 37 cu. ft. of air passing and will permit 70 cu. ft. of free air per minute to pass a brush renovator when operating with 100 ft. of hose attached to the inlet at which the highest vacuum is maintained. Both of these conditions will permit satisfactory operation and the increased air quantities will not seriously affect the calculations already made. The maximum horse power required at the separator will now be 20.5 as against over 50 in the case of the piping arrangement shown in Fig. 63, and will require an exhauster having a displacement of 950 cu. ft. instead of 1,800 cu. ft. required with the former layout. If 1-in. hose is used and 10 in. mercury maintained at the outlet "x" under the same conditions as before, the vacuum at the separator will be 14.50 in. and the maximum variation in the vacuum at the inlets will be 3 in., which will give a maximum vacuum under a carpet renovator of 6 in. mercury with 32 cu. ft. of air passing and will permit the passage of 45 cu. ft. of free air through a brush renovator when operated at the end of 100 ft. of hose attached to the outlet at which the highest vacuum is maintained. This is a more uniform re- sult, than was noted when 1)4 -in. hose was used. The maximum horse power which will be required at the separator will now be 18.6 and the maximum displacement in the exhauster will be 740 cu. ft. It is, therefore, evident that, where very long runs of piping are necessary and where 100 ft. of hose will always be necessary, the use of 1-in. hose will require less power and a smaller dis- placement exhauster than would be required with 1)4 -in. hose, without affecting the efficiency of the cleaning operations, and at the same time rendering the operation of the renovators on extreme ends of the system more uniform. The example cited in Figs. 63 and 64 is not by any means an extreme case to be met in cleaning systems for car yards, and the larger the system the greater will be the economy obtained with 1-in. hose. Such conditions, however, are confined almost entirely to lay- outs of this character and will seldom be met in layouts within any single building. This is fortunate, as the train cleaning is PIPE AND FITTINGS 125 practically the only place where the use of 100 ft. of hose can be assured at all times. Very tall buildings offer a similar condition although the laterals are now vertical and can be kept large enough to suf- ficiently reduce the friction without danger of deposit of dirt in them, and the horizontal branches will be short and also large enough to keep the friction within reasonable limits with- out danger of deposit of dust. Where large areas within one or a group of buildings must be served by one cleaning system, better results can often be obtained by installing the dust separator at or near the center of the system of risers instead of close to the vacuum producer, as indicated in Fig. 65. When this is done, the pipe leading c < i Separator ) r ) J Vacuum Producer ( < "\| J^ c 1 C Clean Air Line FIG. 65. GOOD LOCATION FOR DUST SEPARATOR WHERE LARGE AREAS ARE SERVED BY ONE CLEANING SYSTEM. from the separator to the vacuum producer carries only clean air and can be made as large as desired and the friction loss re- duced, resulting in a considerable reduction in the power re- quired to operate the system. Where the system becomes still larger, two or more separators located at centers of groups of risers can be used and clean .air pipes of any desired size run to the vacuum producer (Fig. 66). When more than one separator is used care should be exercised in proportioning the pipe lines from the separators to the vacuum producer so as to have the friction loss from the vacuum producer to each separator the same in order to .give uniform results at all inlets. This loss should also be 126 VACUUM CLEANING SYSTEMS kept as low as possible in order to prevent a higfti vacuum in a separator serving a portion of the system on which few sweepers are in operation. If low friction losses in the clean air pipe will require larger pipes than it is practical or economical to install, pressure reducing valves might be located in the clean air pipes near the separators to so regulate the vacuum at the separators and insure uniform results. A system of this kind might serve several premises and the air used by each be metered and the service sold much the same as heat and elec- tricity. However, the power required to operate the system would be greater than that needed to operate a similar num- IO Clean Air Line CD FIG. 66. LOCATION OF SEPARATORS AT CENTERS OF GROUPS OF RISERS FOR LARGE SYSTEMS. ber of sweepers by individual plants owing to the higher vac- uum required to overcome the friction in the trunk mains. This would be offset by the use of larger units and the possi- bility of operating them at full load at nearly all times. A system of this kind was contemplated in Milwaukee some seven years ago, but was never installed. The question of pipe friction in connection with the design of vacuum cleaning systems requires careful consideration, much more than it ever received in the early days of the art and a great deal more than it sometimes receives at the present time. CHAPTER VIII. SEPARATORS. The appliances which remove the dust from the air current which has carried it through the hose and pipe lines, in order to prevent damage to the vacuum producer, play an important part in the make-up of a vacuum cleaning system. Classification of Separators. Separators may be divided in- to two classes according to their use: 1. Partial separators, which must be used in conjunction with another separator in order to effect a complete removal of the dust from the air. These separators are again divided into two sub-classes, i. e., primary, or those removing the heavy particles of dust and dirt only, and secondary, or those re- moving the finer particles of dirt which have passed through the primary separator. 2. Complete separators, or those in which the removal of both the heavy and the finer particles of dust is effected in a single separator. Separators may also be classified, according to the method employed in effecting the separation, into dry separators in which all operations are effected without the use of liquid, and wet separators in which water is employed in the removal of the dust. Primary Separators. Primary separators are nearly always operated as dry separators and depend largely on centrifugal force to effect the separation. The first type of primary sepa- rator used by the Vacuum Cleaner Company is illustrated in Fig. 67. This consists of a cylindrical tank, with hopper bottom, containing an inner cylinder fixed to the top head. The dust- laden air enters the outer cylinder near the top on a tangent to the cylinder. The centrifugal action set up by the air strik- ing the curved surface of the outer cylinder tends to keep the 127 128 VACUUM CLEANING SYSTEMS heavy dirt near the outside of same, and as it falls towards the bottom the velocity is reduced and its ability to carry the dust is lost. When the air passes below the inner cylinder the veloc- ity is almost entirely destroyed and all but the very lightest of the dust particles fall to the bottom, while the air and the light dust particles find their way out of the separator through the opening in the center at the top. rf? PIG. 67. EARLY TYPE OF PRI- MARY SEPARATOR, USED BY VACUUM CLEANER COMPANY. FIG. 68. PRIMARY SEPARATOR USED BY THE SANITARY DE- VICES MANUFACTURING COM- PANY. The primary separator used by the Sanitary Devices Manu- facturing Company is illustrated in Fig 68. The inner cen- trifugal cylinder is omitted and the air enters through an elbow in the top of the separator, near its outer extremity, which is turned at such an angle that the air is given a whirling motion SEPARATORS 129 resulting in the dust being separated much the same as in the case of the Vacuum Cleaner Company's apparatus. Either of these separators will remove from 95% to 98% of the dirt that ordinarily comes to them through the pipe lines and are about equally efficient. The separator illustrated in Fig. 69 was used by the General Compressed Air and Vacuum Cleaning Company. The enter- ing air is led to the center near the bottom and is then released through two branches curved to give the air a whirling motion. The clean air is removed from the center of the separator near ft FIG. 69. PRIMARY SEPARATOR USED BY THE GENERAL COM- PRESSED AIR AND VACUUM CLEANING COMPANY. FIG. 70. PRIMARY SEPARATOR MADE BY THE BLAISDELL ENGINEERING COMPANY. the top. This separator is not as effective in its removal of dirt as either of the former types, owing are not exposed to dust, and the air currents when deflected to impinge only upon surfaces which are of heavy metal and where such wear as occurs will not affect the operation and handling of the tool. 59. All renovators -and stems are to be as light as is consis- tent with strength and ability to withstand cutting action of dust. 60. The lips of carpet renovators and upholstery cleaner to be of such proportions and form as will prevent injury to the fabric, and such widths as will reduce to a minimum the stick- ing of renovator face to the material being cleaned. 61. Stems to be not less than 1 in. outside diameter. Air passages in swivels to be same diameter as inside of stem. Stem for use with floor renovators shall be curved near upper end to form handle and provided with swivel to permit hose hanging vertical. 62. Stems to be drawn-steel or brass tubing, not less than No. 21 United States standard gauge thick if steel and not less than No. 16 Brown & Sharpe gauge thick if brass. 63. Carpet renovators to be made preferably of pressed steel, as light as possible, or may be made of oast iron, brass or aluminum with iron wearing face. 64. Bare floor renovators shall have renewable elastic wear- ing face curved in direction of motion when cleaning. 65. All renovators and brushes must be provided with proper rubber or other approved buffers to prevent marring the wood- work. 66. Upholstery cleaners are to have inlet slots or openings of such size and form as to absolutely prevent drawing in loose covering of furniture. 67. Upholstery and corner cleaners are not to be arranged for use with stems, but are to have their own handles perma- nently attached and be provided with hose couplings. 68. All metal parts of renovators and stems are to be fin- ished, and all except aluminum parts nickel plated. 69. Hose. Furnish 75 ft. cleaning hose in three 25-ft. lengths. 70. The hose to be 1^ i n - inside diameter best quality rubber 202 VACUUM CLEANING SYSTEMS hose, reinforced in best manner to absolutely prevent collapse at highest vacuum obtainable with the exhauster furnished and to prevent collapse if stepped on. Weight of hose to be not over 12 oz. per linear foot. 71. Couplings for hose to be either slip, bayonet-lock or all- rubber type, with smooth bore of practically same diameter as inside of hose. The couplings to have least possible projection outside of hose dimensions and be well rounded, so as not to injure floors, doors, furniture, etc. 72. Bayonet joints may have packing washer, and slip joints to have permanent steel pieces on ends of hose and brass slip coupler. All ends of hose at couplings to have outside ferrules securely fastened in place, or pure gum ends glued to coupling. Simple conical slip joints slipped into ends of hose without fer- rules will not be acceptable. All joints must fit together so that they will not be readily pulled apart. 73. Tests. All piping to be tested w r ith air pressure equal to 5 in. mercury before being concealed in walls and other spaces. Mercury must not fall more than y\ in. in one-half hour. 74. On completion of plant the pump will be operated with all outlets closed and, under these conditions, there must be an interval of not less than 10 min. between the stopping and starting of the motor by the automatic control, if pump system is used. And if fan system be used, the power required to operate the exhauster must not be more than 65% of that re- quired in capacity test. 75. To test the capacity of the separator, a mixture contain- ing 6 Ibs. of sand, passed through a 50-mesh screen, 3 Ibs. of common wheat flour and 16 Ibs. of Portland cement shall be spread over 50 sq. ft. of floor and picked up with a renovator attached to the end of 50 ft. of 1*4 -in. hose. The machine shall be stopped and the material removed from the separator spread on floor and picked up. This procedure shall be repeated until the material has been handled four times. If the separator contains a bag, the same must not be disturbed until after com- pletion of the capacity test, which will be made with the material in place in separator, after being picked up the fourth time. SPECIFICATIONS 203 After completion of capacity test, the contents of separator shall be weighed and if same be a partial separator it must contain 95% of the material picked up. If a displacement machine is used as a vacuum producer, the separator must pre- vent the passage of any dust through separator, which will be determined by holding a dampened cloth over pump outlet during test of apparatus. Said cloth must not show any dust lodged thereon at end of /test. 76. To test the capacity of the plant a standard vacometer, attached to the end of 75 ft. of cleaning hose shall show a vacuum of 2 in. mercury with ^-in. diameter orifice open. 77. Test of Cleaning Tools. The plant shall be operated by the Contractor in the presence of the Architect's representative, and a test made of each kind of cleaning tool furnished. The tool shall be attached to a 50-ft. length of hose attached to an outlet selected by the Architect's representative, and under normal working conditions each tool must satisfactorily perform the work for which it was designed. Dust and surfaces to be cleaned shall be furnished by the contractor. 78. Painting. After the completion of the specified tests, all exposed iron work except galvanized iron or tinned work in connection with this apparatus, not specified to be otherwise finished, shall be primed with paint suitable for surfaces covered, and then given two additional coats. Machinery shall be painted as already specified, and all other work shall be given finishing tints as selected or approved by the architect. Black iron pipe, etc., shall be given two coats lead and oil of tint directed. Modifications of Specifications when Alternating Current is Available. When alternating current is available, instead of direct, modify specifications as follows : 23. Motor to be wound for .... volts, . . . .cycle, . . . .phase alternating current. 24. Motor to have rotor of the squirrel cage type. Omit 25, 26 and 27. 28. To remain as for direct current. 29. There must be an insulation between the starter or pri- mary windings and the frame of not less than one megohm. 30. 31, and 32. Same as for direct current. 204 VACUUM CLEANING SYSTEMS 33. Tablet. Furnish and mount where directed a polished slate tablet having mounted thereon a 30 ampere, 250 volt, .... pole knife switch with enclosed indicating fuses and; if displacement type exhauster is furnished, an automatic starter of the ''across the line" type, operated by vacuum in the separator which will stop motor when the vacuum in the sepa- rator rises 2 in. above that required to meet test conditions, and start exhauster when vacuum reaches working range. CLASS 2 PLANT FOR LARGE OFFICE BUILDING HAVING PIPE LINES OF MODERATE LENGTH. 1. Same as for Class 1. 2. Omit centrifugal fan. 3 to 9. Same as for Class 1. Omit 10 to 13. 14 and 16. Same as for Class 1. 15. Omit centrifugal fan. Omit 17 and 18. 18a. Base Plate, Foundation, etc. Provide suitable base plate to rigidly support the exhauster and its motor as a unit, which shall be large enough to catch all drip of water or oil. Provide a raised margin and pads for feet of exhauster frame, motor, and anchor bolts, high enough to prevent any drip from getting into the foundation or on the floor. 18b. Provide suitable foundation of brick or concrete, to which the base plate shall be firmly anchored. The foundation shall be built on top of the cement floor of the basement, which shall be picked to afford proper bond for the foundation. 18c. Construct the foundation of such a height as to bring the working parts of the machine -at the most convenient level for operating purposes. Exposed parts of the foundation to be faced with best grade white enameled brick. If the base plate does not cover the foundation, the exposed top surface is to be finished with enameled brick, using bull-nose brick on all edges and corners. 19 to 23. Same as for Class 1. 23a. The guaranteed efficiency of motor shall not be less than 78% at half load and not less than 84% at full load. 24 to 32. Same as for Class 1. SPECIFICATIONS 205 32a. Motor shall be subject to shop test to determine effi- ciency, heating, insulation, etc. Manufacturer's certified test sheets of motor giving all readings taken during shop tests, together with calculated results, must be submitted to the Archi- tect for approval before motor is shipped from factory. 33. Rheostat. Furnish and install where shown, upon a slate panel hereinafter specified, a starting rheostat of proper size and approved made, designed for the particular duty it has to perform. It must have an automatic no-voltage and over- load release. All resistance for rheostat is to be placed on the back of the tablet. Contacts must project through board to front side. All moving parts must be on front of board. 33a. Tablet. Furnish and place where shown, a slate tab- let not less than y$ in. thick, supported by a substantial angle iron frame, so placed that there will be a space of not less than 4 in. between the wall and back of resistance. Mount on this tablet one double-pole, 250-volt knife switch, with two 250-volt inclosed fuses and one starting rheostat, as specified hereinbe- fore. The connections shall be on the back of the tablet. The space between the column and the tablet shall be inclosed with a removable diamond-mesh grill of No. 10 iron wire in channel frame. 34, 35, 36. Same as for Class 1. 36a. Automatic Control. Suitable means shall be provided in connection with the rotary exhausters that will maintain the vacuum in the separators within the limit of the machine at point found to be most desirable, irrespective of the number of sweepers in operation. 36b. Controller shall consist of a suitable means provided in the exhauster, or as an attachment thereto, which will auto- matically throw the exfhauster out of action by admitting atmos- pheric pressure to the exhauster only, but not to the system whenever the vacuum in the separators rises above the point considered desirable, and throw the exhauster into action when the vacuum falls below the established lower limit. 36c. Vacuum Breaker. In addition to the controlling devices above specified there shall be placed in the suction pipe to the exhauster an approved positive-acting vacuum breaker having 206 VACUUM CLEANING SYSTEMS opening equivalent to the area of 1-in. diameter pipe and set to open at 10 inches vacuum. (If plant is to be run for long periods without much load, as in a hotel, omit 36a, b, c, and substitute) : 36d. Automatic Control. An approved type of controller for maintaining practically a constant vacuum by varying the speed of the motor driving exhauster arranged to permit the operation of the motor continuously at any speed between full speed and stop, so long as there be no change in vacuum and which will increase speed whenever vacuum falls and reduce speed whenever vacuum rises, must be provided. 37. Dust Separator. There shall be one dry separator located where shown on plans, having a volume of not less than 3 cu. ft, for each sweeper of plant capacity. 38. The interior arrangement of the separator shall be such that no part of same will receive the direct impact of the dust. Cloth bags or metal screens, if used in this separator, shall be so placed that nothing but the very lightest of the dust can lodge thereon, and that same may be easily cleaned without dismantling the separator. It must be so constructed that it will intercept all of the dust entering same. 38a to 56. Same as for Class 1. 56a. Tool Cases. Furnish approved hardwood cabinet-fin- ished cases for cleaning tools. Each case to be made as light as possible and of convenient form for carrying by hand and provided with a complete set of cleaning tools, each securely held in its proper place, and fitted with lock and key, clamps, and conveniently arranged handles. 57. Each case shall contain the following: One carpet renovator, with slot ^4 i n - D 7 15 in. One bare floor renovator, 15 in. long, with curved felt-cov- ered face. One wall brush, with skirted bristles, 12 in. long and l / 2 in. wide. One hand brush, with hose connections at end, 8 in. long, 2 in. wide. One 4-in. round brush for relief work. SPECIFICATIONS 207 One upholstery renovator. One corner cleaner. One radiator tool. One curved stem about 5 ft. long. One extension tube 5 ft. long. At least one hat brush with the system. 58 to 64. Same as for Class 1. 64a. All brushes to be of substantial construction, with best quality bristles set in close rows and as thick as possible, skirted with rubber, leather, or chamois skin, so that all air entering renovator will pass over surface being cleaned. 65 to 68. Same as for Class 1. 69. Hose Racks. Furnish and properly secure in place, where directed, .... hose racks in basement, .... each in first and second stories ( . . . . racks in all). The racks to be constructed of cast iron, galvanized or enamel finish, and each rack to be suitable for holding 75 ft. of hose of required size. 69a. Hose. There must be furnished with each hose rack 75 ft. of noncollapsible hose in three 25-ft. lengths. 70 to 73. Same as for Class 1. 74. On completion of the plant the pump will be operated with all outlets closed, and, under this condition, the power consumption must not be more than 50% of that required under test conditions. 75. Test of Separators. At each of points, near out- lets on different risers selected by the architect's representa- tive, the contractor shall furnish and spread on the floor, evenly covering an -area of approximately 50 sq. ft. for each outlet, a mixture of 6 Ibs. of dry sharp sand that will pass a 50-mesh screen, 3 Ibs. of fine wheat flour and 6 Ibs. of Portland cement. 75b. Fifty feet of hose shall be attached to each of the outlets, and the surfaces prepared for cleaning shall be cleaned simultaneously by operators provided by the contractor until all of the sand, flour and Portland cement has been taken up, when the exhauster shall be stopped and the dirt removed from the separator and spread on the floor again, and the operation 208 VACUUM CLEANING SYSTEMS of cleaning repeated until the mixture has been handled by the apparatus four times. The bag contained in the separator must not be disturbed until after completion of the capacity test, which will be made with material in place in the separator after being picked up the fourth time. After completion of the capacity test the contents of separator will be removed. During test of sepa- rators a dampened cloth will be held over the exhaust from pump. If such cloth indicates dirt passing through the sepa- rator, same will be rejected. 76. To test the capacity of the plant, one hose line 100 ft. long shall be attached to inlet farthest from the separator with standard vacometer, with ^2 -in. opening in end of hose hose lines shall be attached to other outlets, each with 50 ft. hose and vacometers in end of hose, .... vacometers having ^2 -in. opening 'and .... vacometers having %-in opening. Under these conditions 4 in. mercury must be maintained in vacometer at end of 100 ft. of hose. 77 and 78. Same as for Class 1. Modifications of Specifications when Alternating Current is Available. When alternating current is available, instead of direct, modify specifications as follows: 23. Motor to be wound for .... volts, .... cycle, .... phase alternating current. 23a. Bidders must name efficiency and power factor of motor at one j half and full load. 24. Motor to have phase-wound rotor with collector rings for insertion of starting resistance. Omit 25, 26 and 27. 28. Same as for direct current. 29. There must be an insulation between the starter or pri- mary windings and the frame of not less than one megohm. 30. 31, 32, 32a. Same as for direct current. 33. Rheostat. Furnish and install an approved hand-starting rheostat for inserting resistance in rotor circuit in starting, of proper size to insure the starting of motor in not exceeding 15 seconds without overheating. SPECIFICATIONS 209 33a. Same as for direct current, except that switch must be either three- or four-pole, according to current available. Omit 36d with alternating current machine. CLASS 3 LARGE INSTALLATION WITH UNUSUALLY LONG PIPE LINES. 1. Same as for Class 1. 2. Exhauster shall be of the reciprocating piston type. 3. The piston type of exhauster shall be double acting and so designed that the cylinder clearance shall be reduced to a minimum, or suitable device shall be employed to minimize the effect of large clearance. 4. The induction and eduction valves may be either poppet, rotary, or semi-rotary, and shall operate smoothly and noise- lessly. 5. The piston packing shall be of such character as to be practically air tight under working conditions and constructed so that it will be set out with its own elasticity without the use of springs of any sort. If metallic rings are used, they must fill the grooves in which they are fitted, both in width and depth, and must be concentric; that is, of the same thickness throughout. The joint in the ring or rings to be lapped in width but not in thickness, and if more than one ring is used they are to be placed and doweled in such position in their respective grooves so that the joints will be at least one-fourth of the circumference apart. 6. The piston shall have no chamber or space into which air may leak from either side of the piston. All openings into the body of the piston must be tightly plugged with cast-iron plugs. 7. The piston rod stuffing box to be of such size and depth that if soft packing is used it can be kept tight without undue pressure from the gland. If metallic packing is used, it must be vacuum tight without undue pressure on the rod. Proper means shall be provided for the continuous lubrication of the piston rod. 8. The exhauster of the piston type shall be fitted with an approved cross-head suitably attached to the piston rod ; ma- 210 VACUUM CLEANING SYSTEMS chines having an extended piston rod for guide purposes will not be acceptable. Omit 9 to 13. 14. Same as for Class 1. 15. Reciprocating piston exhauster shall be provided with the necessary devices for the removal of the heat generated by friction and compression, that shall prevent the temperature of cylinders or eduction chambers rising more than 100 F. above the surrounding atmosphere after two hours' continuous oper- ation under full-load conditions. 16. Speed. Reciprocating exhauster with poppet valves shall operate at an average piston speed not exceeding 200 ft. per minute, with rotary valves not exceeding 300 ft. per minute. Omit 17 and 18. 18a. Ease Plate, Foundation, etc. Provide suitable base plate to rigidly support the exhauster and its motor as a unit, which shall be large enough to catch all drip of water or oil. Provide a raised margin and pads for feet of exhauster frame, motor, and anchor bolts, high enough to prevent any drip from get- ting into the foundation or on the floor. 18b. Provide suitable foundation of brick or concrete, to which base plate shall be firmly anchored. The foundation shall be built on top of the cement floor of the basement, which shall be picked to afford proper bond for the foundation. 18c. Construct the foundation of such a height as to bring the working parts of the machine at the most convenient level for operating purposes. Exposed parts of the foundation to be faced with best grade white enameled brick. If the base plate does not cover the foundation, the exposed top surface is to be finished with enameled brick, using bull-nose brick on all edges and corners. 19 to 23. Same as for Class 1. 23a. The guaranteed efficiency of motor shall not be less than 80% at half load and not less than 85% at full load. 24 to 32. Same as for Class 1. 32a. Motor shall be subject to shop test to determine effi- ciency, heating, insulation, etc. Manufacturers' certified test sheets of motor, giving all readings taken during shop test, to- SPECIFICATIONS 211 gether with calculated results, must be submitted to the Archi- tect for approval before motor is shipped from factory. 33. Rheostat. Furnish and install where shown, upon a slate panel hereinafter specified, a starting rheostat of proper size and approved make, designed for the particular duty it has to perform. It must liave an automatic no-voltage and over- load release. All resistance for rheostat is to be placed on the ba