CHAPTER VII HOUSEHOLD REFRIGERATING MACHINES (Part 6)

units made by the Warner Stacold Corporation of Ottawa, Kansas. Air-cooled sulphur dioxide compressors are made in the lie. 1-19. WAK.N'EK STACOLD C OMi'RESSOK VKiV. following sizes: 1-cylinder com|)ressors driven by % and 34 hj). motors; 2-c}"linder compressors driven by _^ and ^3 hp. motors; 3-cylinder compressors driven by Jj, .)4 'ind 1 hp. motors. These compressors are of the slow speed reciprocating type. A special "V" belt is used. The compressors have crank shafts which oi)eratc with less friction tlian eccentrics. FIG. 150.— WAKNKR SlWCOLl) Cd.\l I'R I'SSOK I'Nl'l'. Ground removable cylinder sleeves are used. The commercial compressors have pistons equipped with 4 rings. A series of 8 sizes of cooling tanks are made suitable for the various refrigerators. Flooded t> pe cooling coils are also made. These coils are used in apartment houses and commercial installations where COMPRESSION REFRIGERATING MACHINES 287 it is necessary to have more than one cooling coil connected to one compressor. Metal cabinets are manufactured from 4.6 to 10.5 cubic feet food storage space. These cabinets are insulated with cork. The exterior has a lacquer finish. The interior is of white enamel or porcelain. Welsbach. — This machine, Fig. 151, is manufactured by the Welsbach Company at Gloucester, N. J. The refrigerant used is "Alcozol," which has been de- veloped in the Welsbach chemical laboratories. "Welcolub," FIG. 151.— WELSBACH COMPRESSOR UNIT. another product of the Welsbach laboratories, is used as the lubricant. The compressor is of the horizontal, double acting type. The compressor cylinder has a bore of 3 inches, with a stroke of 1 inch. It operates at low speed — 280 revolutions per min- ute. In normal operation in a 90° F. room the condensing pressure is 20 to 25 lbs., while the suction pressure is a vacuum. General Electric and Century ]/^ hp. motors are used, operating at 1750 revolutions per minute, with an average 288 HOUSEHOLD REFRIGERATION connected load of 210 watts. The motor drives the compres- sor by means of a ruliber-fa'bric "A"' t\i)e belt. FIG. 152.— WF.LSHArir FUKFZiNT, T'XIT. The condenser is made of ^-inch copper tubing. Forced air cooling is obtained by means of a two-blade fan on a motor pulley, and fan blades in the compressor pulley. The con- denser supplies liquid refrigerant to a receiver of sufficient size to hold the entire charge. Fig. 152 shows the freezing unit made of tinned copper, containing a non-freezing solution of glycerine and water. COMPRESSION REFRIGERATING MACHINES 289 The c.\i);iiisi()n <(iils arc made ot ^^-inch copper tul)ing-, pan- cake vvindinj^. A downward pitch in the evaporator permits the draina.^e of circulated luliricant Iiack to the com])ressor. An expansion Aalvc is used and automatically maintains a predetermined \acuum, regardless of the condensing pres- stirc. K;. 153.— WELSr.ACII STEEI. CABINET. The automatic tem[)eraturc control consists of a mercury switch mounted on a bi-metallic coil sealed in a bakelite case. The control is mounted on the u])per right-hand corner of the cooling tank. Fig. 153 shows a ty])ical steel cabinet as manufactured b}- the Welsbach Comi)any. Mg. 15-f shows a typical hardwood cabinet made of S'])\ Inininated wood, using flush i)anel con- 290 HOUSEHOLD REFRIGERATION FIG. 154.— WELSBACH HARDWOOD CABINET. structioii. Both the steel and wood cabinets are supplied in various models. The dimensions, food storage space, number of trays and number of ice cubes vary with different models. Whitehead. — Fig. 155 shows the compressor unit used with the household refrigerating machine manufactured by the Whitehead Refrigeration Company of Detroit, Michigan. The compressor is of the reciprocating type. It is con- nected directly to the motor shaft and operates at motor speed, thus eliminating belts or gears. A flexible coupling is used to connect the motor and compressor shafts. The condenser is made of finned tubing and is cooled by forced air. The fan is mounted on the compressor motor shaft. Methvl chloride is used as the refrigierant. The receiver COMPRESSION REFRIGERATING MACHINES 291 FIG. 15S.-WHITEIIEAD COMPRESSOR UNIT. a i\ iimi FIG. 1S6.-WHITEHEAD COOLING UNIT. 292 HOUSEHOLD REFRIGERATION contains a visililc gauiic slmwing the amount of rcfris^erant contained in the receiver. ^fhe temperature control is of the mercury tube type. Fig. 156 shows a ty])ical coolint^' unit. 'Jliis is made in five sizes as follows : Maximum Cube Tank Ice Box Capacity per Size Width Dcjitli Height Capacity Freezing 1 10 in. 11 in. 10 in. 5-7 cu. ft. 96 2 10 in. 11 in. 13 in. 8-10 en. ft. 96 3 10 in. 11 in. 16 in. 11-15 en. ft. 144 4 11 in. 1 1 in. 19 in. 16-20 cu. ft. 144 5 11 in. 11 in. 23 in. 20-30 cu. ft. 192 Williams Simplex. — An air cooled refrigeratino- machine was develo]>ed tor household use called the \'illiams Simplex. Ethyl chloride is used as the refrigerant. The compressor is of the rotary tyi)e, directly connected to the motor shaft without employment of intermediary gear- ing or belting. The comi)ressor has a xolumetric efficiency ranging from 82 ])er cent to 85 per cent, and a mechanical ef^ciency comparing favorabl) with the best reciprocating types of many times greater cajjacit}-. .\ ground steel collar is used to seal the drixe shaft. This collar is self-aligning and automaticall} takes up \ear. as it is attached to the com])ressor b\ means of a corrugated metallic tube. A spring, assisted 1)\ the condensing pressure, holds these mend)ers in firm contact. This forms a tight joint, which will run indefinitely without a tendenc}' to wear or break down. The compressor is mounted integrally with and supported by the mentor. Positive ])ressure feed of lubricant is main- tained to all moving elements of the compressor while in operation. The compressor and condenser are cooled entirely by main- taining a current of air over their surfaces. The air is circu- lated by means of a Sirocco type of blower mounted between the motor and the compressor, the blower casing forming the supporting bracket for the compressor. The air is first drawn through the condenser chamber which cr)ntain-; a continuous coil of cop])er tubing into which COMPRESSION REFRIGERATING MACHINES 293 the refrigerant \ap<»r is compressed, taking u) the hitent heat of vaporization ; it then passes over the heat radiating lins of the compressor, from which it discharges through a flue ex- tending through the top of the machine cover. Air is also simultaneously drawn from the opposite direction through and around the motor and discharged from the fan as above described. The so-called flooded system is employed, in which the expansion or cooling coils are filled with liquid refrigerant. These coils connect into a vertical header from the toj) of which the \ aporized refrigerant is drawn. This \aiJor, after being licjuetied in the condenser, is discharged into a small chamber fitted with a float \alve, whicJT ])ermits it to feed back into the expansion coils at the same rate at which it is Deing condensed. These features are important, in that the radiating surfaces of the cooling coil have a much higher heat transmitting capacity when full of lic^uid. The ratio to the usual method of gas expansion at constant ])ressure is about 1.56 to 1. A still more important advantage is that the expansion pressure is automatically varied to maintain constant balance between the compressor capacity and the radiating surfaces as the temi)erature changes. This provides maximum efiiciency operating conditions throughout any range of temperature, while in the usual gas expansion method the pressure is neces- sarily set and held for the lowest temperature required, which is alwa\s the condition of lowest efficiency. The machine is controlled by means of a thermostat, ar- ranged to operate responsive to the temperature of the brine surrounding the coils in the brine tank. The switching appa- ratus and its actuating motor are located on the machine base, while the bulb of the instrument only is located in the tank. The advantage of placing the thermostat bulb in the brine tank is due to the fact that the maximum temperature change occurs in the brine. A safety pressure switch is also used, which is operated directly responsive to the refrigerant condensing pressure. The machine has a capacity when operating at 15° F. of about 150 lbs. ice equi-alent per 24 liours. The power con- 294 HOUSEHOLD REFRIGERATION sumption, including motor losses, is from 190 to 200 watts with direct current, and from 260 to 300 watts with alternating current, the difference being due to the larger losses in the alternating current motor. Zerozone. — The Zerozone Household Electrical Refrigerat- ing Unit is manufactured by the Iron Mountain Company of Chicago, Illinois. This is an air-cooled compressor type unit using a cooling unit of the indirect type. The refrigerant used is sulphur dioxide. FIG. 157.— ZEROZONE ELECTRICAL REFRIGERATING UNIT. The compressor unit consists of a one-cylinder reciprocat- ing type compressor which is used on all well insulated re- frigerators up to 20 cu. ft. and is shown in Fig. 157. The bore and stroke is 1^ inch and the compressor operates at 330 r.p.m. The compressor is driven by a 34 hp. repulsion induc- tion electric motor by means of a "V" type belt. A two cylinder type compressor is used on all refrigera- tors from 20 to 50 cu. ft. and is shown in Fig. 158. The bore and stroke is 1^ inch and the compressor operates at 265 r.p.m. driven by a 5^ hp. repulsion induction electric motor by means of a "V" type belt. COMPRESSION REFRIGERATING MACHINES 295 a j^ FIG. 158.— ZEROZONE TWO-CYLINDER TYPE COMPRESSOR. FIG. 159.— ZEROZONE AUTOMATIC CONTROL. 296 HOUSEHOLD REFRIGERATION The condenser in each case is a double copper coil cooled by forced air by means of a fan attached to pulley end of the motor shaft. The control used on the individual installation is an auto- matic thermostat, Uxg. 159. and is responsive to the tempera- I'lG. 160.— ZEROZONE COOLING UMT. ture in the cooling unit. The thermostat tube in the cooling unit connects to a sylphon which operates a mercury tube switch, by means of a suitable lever mechanism. The control used on the Multiple installation is of the low pressure type, and is responsive to the pressures in the low- side of the refrigerant system. This lo\- pressure control. COMPRESSION REFRIGERATING MACHINES 297 controls the oijcration of the conii^ression unit itself, the tem- perature of each cooling unit in the multiple installation being controlled indixidually l)y a Idw side, thermostatic actuated valve. commi)iil' referred to as a teni))erature g•o^■ern(Jr. FIG. 161.— ZEROZONE SELF-COXTAIXED METAL CABINET. A diaphram type expansion valve is used to automatically meter the correct supply of liquid refrigerant to the expansion coils. The cooling units are made of 20 ounce sheet copper, made in -arious sizes, one of which i> shown in Fi^. 160. and con- 298 HOUSEHOLD REFRIGERATION tains ^-inch copper tubing for the expansion coil. The non- freeze solution is calcium chloride. Fig. 161 shows a typical self-contained cabinet, the ex- terior of which is metal, finished with white lacquer. Cork- board is used to insulate the walls and doors. The lining is of the one piece porcelain on steel type. The cabinets are made in A^arious stvlcs and sizes.