CHAPTER VII HOUSEHOLD REFRIGERATING MACHINES (Part 3)

a self-contained unit. A copper finned cooling coil is used. The compressor is mounted on a special spring suspension to eliminate vibration and afford c^uietness in operation. Fig. 87 shows the cabi-net in which the self-contained unit is used. General Electric. — The General Electric Refrigerator is made by the General Electric Com])any of Schenectady, N. Y. Fig. 88 shows the complete refrigerating unit installed in a refrigerator cabinet. The refrigerant used is sulphur dioxide. All moving parts are hermetically sealed in a drawn steel case containing the refrigerant — sulphur dioxide — and the lul:)ricant. The con- denser and evaporator coils are brazed to the steel casing. Specially developed insulated leads, similar to spark plugs, are used for the electrical connection to the motor. This construction permits complete enclosure and the elimination of the stuffing box through which gas or oil might leak. There is no external piping, cooling fan, belt or other external mov- ing part. The essential operating parts consist of: 1. A %-hp., 110-volt, 60-cycle, split-phase motor mounted ver- tically. This motor is exceedingly simple in design and sturdy in con- struction— without brushes or other moving contacts. 2. A two-cylinder, single-acting compressor having oscilating cylinders. 3. A discharge valve of spring steel so arranged as to eliminate noise. 4. A copper tube condenser coil of circular cross section. 5. A float valve to regulate the amount of refrigerant passing to the evaporator coils. 6. An evaporator coil of copper tubing immersed in the brine tank. 7. An automatic regulating control. The cooling tank, which is suspended within the cabinet itself, is covered inside and out with white, fused-on vitreous 228 HOUSEHOLD REFRIGERATION porcelain— long wearing- and easy to clean. The freezing trays, having a capacity of seven pounds of ice cubes, can be slipped into compartment in the tank. These trays are FIG. S8.— GENERAL ELECTRIC REFRIGERATOR. of heavily tinned copper and are furnished with removable dividers to provide twenty-one cubes for each tray, or a total of sixty-three cubes for the three trays. COMPRESSION REFRIGERATING MACHINES 229 Complete automatic temperature and current control are provided. A control box on the front of the unit contains a manually-operated switch for disconnecting the machine, for defrosting or any other purpose. The control box also contains an automatic thermostatic switch for starting and stopping the machine in response to temperature changes, a relay for transferring motor connec- tions from starting to running position and a thermal, time- limit relay for protecting the motor from overload damage, also a reset button for a resumption of operation. The automatic control is so adjusted that a brine tempera- ture is maintained between 16° and 24° F., thereby maintaining a continuous cal^inet temperature of from 40° to 50° F., which is admittedly the most satisfactory temperature for food preservation. Installation is extremely sim])le as the refrigerator need only be moved to the desired position and attached to the near- est electric outlet. It can be installed wherever it will prove most convenient as there is no special )3lumbing or permanent fixtures to be connected to it. The cooling tank is placed in the cabinet, filled with a solution of salt brine and the re- frigerating unit set into place. It is thoroughly portable and can readily be moved. Fig. 88 shows the Model P-5-2 installed in a 5 cu, ft. refrig- erator. This cabinet is of white porcelain exterior and inte- rior. The exterior has fiat polished metal trim strips. The exterior dimensions are height overall, 65^ inches; width over hardware, 2S^.'i inches ; depth over hardware, 22% inches. (Legs may be removed and the height reduced 11^ inches.) The cooling unit contains one small tray for making ice cubes and one large tray for making cubes or frozen dessert. The total ice-making capacity is 56 cubes or approximately 7 pounds of ice. The food storage capacity is 5.37 cubic feet and the food shelf area is 7.9 square feet. Hall Refrigerating Machine. — Fig. 89 shows the compres- sor of the ammonia machine manufactured by Thomas Hall & Son, Ltd., Rotherham, England. The piston is of the truncated type and contains the sue- 230 HOUSEHOLD REFRIGERATION tion valve. The discharge valve is of a special type. It is not affected by the heat of the compression. The valve is con- tained in a safety head which allows any liquid ammonia or oil to pass without damage. FIG. S9.— HALL REFRIGERATING MACHINE. The crank case gland screws u) like a nut, wliich prevents the gland from being pulled on one side and thus scoring the shaft. Metallic packing is used. The connecting rod is of forged steel. The dirt separator is fitted on the suction pipe, thus preventing any scale which may become loosened in the room coils from entering the machine and interfering with the working of the valves. An oil sight glass is fitted in the end cover, wdiich enables the level of the oil to be seen at a glance. COMPRESSION REFRIGERATING MACHINES 231 The stop valves are double seating^, allowing the valves to be packed while the machine is running. The machine is fitted with a purge valve on the cylinder head to enable air and foul gases to be purged out of the system. An oil trap is fitted on the discharge and is equipped with an oil return valve which enables the oil carried over through the valve, to be returned to the crank case, thus preventing it from going into the system. A liquid ammonia receiver is fitted underneath the con- denser making a compact unit. The method of cooling usually adopted is by means of di- rect expansion coils immersed in a brine accumulator tank, w^hich acts as a reservoir of cold and keeps the room down in temperature after the plant has been stopped. For some requirements air circulation is added. For frozen meat, direct- expansion coils are placed on the ceiling or on the walls. This small size machine is capable of cooling a properly insulated cold room of 400 to 500 cubic feet to a temperature of 35° to 38° F. Ice Maid. — The household refrigerating unit, Fig. 90, is made by the Lamson Company, Inc., at Syracuse, New York. FIG. 90.— ICE MAID HOUSEHOLD REFRIGERATING UNIT. The compressor is a direct connected rotary type running at motor speed and using ethyl chloride as a refrigerant. The compressor has a 2-bladed rotor mounted eccentric to the bore and is carried on annular ball bearings. The stuffing 232 HOUSEHOLD REFRIGERATION box is of the sylphon bellows type, the bellows revolving with the shaft thereby carrying away any heat that may be generated by the seal. The discharge valve is of the flapper valve type and con- sists of two flat steel discs riveted to the seat on one side. An efficient oil separator is an integral part of the oil reservoir, it is located in the dome of the pump and oil is fed by the ]>ressure of the gas through holes drilled in the pump casting to the bearings and the rotor. This gives the effect of a full pressure system and is fully automatic, as the load on the pump increases the quantity of oil fed to the bearing also is increased. Oil is used as a lubricant increasing the efficiency of the i)ump considerably. Suction and discharge shut-off valves are of the double- seated type permitting removal of pump without losing the charge of refrigerant. A check valve of the flat disc tyi)e is located on the suction side of the pump to obxiate the possibility of oil running back into the suction line. The compressor is driven through a flexible coupling of the fabric disc type which is self-aligning. Coupling and fan hub are integral. The motor is of the induction repulsion type, both Vs and 14 liP- being used. For remote control the motors run at 1750 r.p.m. and for self-contained installation they run at 1165 r.i).ni. The motor is directly connected to the C()m])ressor by means of the fan and coupling assembly. The condenser is of the Honeycoml) Radiator type and has a cooling capacity equal to about 120 feet of 3^ -inch cop- per tubing. This is mounted between the pump and the fan. The fan running at motor speed throws a current of air directly through the radiator and thence around the pump. This direct positive cooling system is so effective that the machine usually operates under several pounds less head pres- sure than ordinary ethyl chloride systems using a copper tube condenser. The compressor, radiator and motor are mounted as a unit on a rigid cast iron base. The base is drilled in such a manner that any standard motor that may be used can be mounted upon it readily. The base rides on sponge rubber balls which effectively absorb any slight noise or vibration. COMPRESSION REFRIGERATING MACHINES 233 "" Attached to the side of the base is a receiving tank of a capacity sufificient to hold the entire charge of refrigerant, thus making the entire condenser available for condensing purposes. The dimensions of the entire unit are 24 inches long, 18 inches high and 12 inches wide. Due to this extreme com- pactness, the standard unit may be mounted in much less space than that occupied by the average machine and this can be installed in the base of a comparatively small refrigerator, FIG. 91.— ICE MAID FREEZING UNIT. without any changes whatsoever. The weight of the entire mechanical unit is approximately 100 pounds. The freezing unit. Fig. 91, is of the brine tank type having a copper expansion coil of ell-shaped form and is equipped with compartment for ice trays. The tanks are nickel plated and are furnished in a variety of sizes sufficient to accommo- date all standard refrigerators. The ice trays have a capacity of 24 cubes of ice. The tray compartment is equipped with a cover which is so designed that it will not freeze to the tank and thus make it difficult to remove the ice tray. 234 HOUSEHOLD REFRIGERATION The expansion valve is of the bahmced type having only one spring- which is the adjusting spring. It is constructed with a sylphon bellows and is fully automatic in its action. It is readily adjustable from the outside and is provided with an efficient means preventing moisture freezing and inter- fering with the operation of the bellows. FIG. 92.— ONE OF THE TWKLN'E ICE MAID MODELS. Control of the machine is effected by means of a mercoid switch located outside the refrigerator. It is connected to the refrigerator by means of a capillary tube which is attached to a bulb immersed in the brine, the other end of the tube being connected to a sylphon bellows actuating a tilting glass COMPRESSION REFRIGERATING MACHINES 235 tube containing" mercury, which makes or breaks the circuit as the bulb is tilted l)ack and forth. A brine temperature of 16° or 20° is maintained. This method of control gives uniform brine temperature regardless of outside temperature. Only one size compressor is furnished, but by substitution of butane for ethyl chloride comparatively large restaurant, butcher boxes and other com- mercial applications can be handled. A complete line of refrigerators with self-contained units are furnished in both wood and all metal comprising twelve different models from 5 to 20 cu. ft. food storage capacity. Fig. 92 shows one of these models. Installation is simple as there are no electric wires enter- ing the refrigerator and the standard mechanical unit is read- ily installed either as a remote or self-contained unit. Iroquois. — Fig. 9i show^s the compressor-condenser unit, made by the Iroquois Refrigeration Company, associate of the FIG. 93.— FRONT VIEW. IROQUOIS COMPRESSOR-CONDENSER UNIT. Barber Asphalt Company of Philadelphia, Pennsylvania. Ethyl chloride is used as the refrigerant. Fig. 94 shows the rotary type compressor used with this' 236 HOUSEHOLD REFRIGERATION unit. The condenser, Fig. 96, is of the double header type consisting of a series of copper tubes arranged so as to form a guard for the compressor. The condenser is cooled by two FIG. 94.— IROQUOIS ROTARY TYPE COMPRESSOR. FIG. 95.— IROQUOIS PRESSURE CONTROLLED SWITCH. FIG. 96.— REAR VIEW, IROQUOIS COMPRESSOR-CONDENSER. COMPRESSION REFRIGERATING MACHINES 237 FIG. 97.— IROQUOIS COOLIXG UNITS. APARTMENT HOUSE UNIT AT LEFT. FIG 98— IROQUOIS SYPHON ALL-METAL CABINET EQUIPPED WITH COMPLETE SELF-CONTAINED REFRIGERATING UNIT. 238 HOUSEHOLD REFRIGERATION fans, one on the motor shaft and the other on the compressor flywheel. The automatic pressure controlled switch is shown in Fig. 95. This device consists of the pow^erful snap, switch actuated FIG 99.- -IROQUOIS ELECTRICAL REFRIGERATOR, APARTMENT HOUSE TYPE. by a diaphragm subjected to a pre-determined pressure in the cooling unit. The cooling units, as Fig. 97, are constructed of heavy tinned copper and brass material. A float valve is used to control the flow of liquid refrigerant to the cooling unit. Figs. 98 and 99 show a typical cabinet equipped with the refrigerating unit forming a complete self-contained model. COMPRESSIOiM REFRIGERATING MACHINES 239 Isko — First Model. — The first model Isko machine is de- scribed as follows : The motor operates the compressor and is controlled through the thermostat and the circuit breaker. When the refrigerator gets warm the themostat starts the motor, which runs until a predetermined low temperature is attained and then stops. The thermostat is located in the cooling coil where the greatest variation of temperature is, there being nearly 32° of variation under a\erage conditions. The thermostat alternates on from 2° to 4° of variation. Isko cools the refrigerator by abstracting the heat through the tinned copper ice-making coils in which liquid sulphur dioxide is being l^oiled by the heat extracted from the re- frigerator. This sulphur dioxide steam, unlike the steam with which we are most familiar, is cold (14° F.). This is sucked into the compressor at atmospheric pressure and elevated in both temperature and pressure to the corresponding temperature of the room. In the condenser (which is a coil of pipe surrounding the apparatus as a guard), this warm sulphur dioxide steam loses its heat by radiation to the surrounding atmosphere, causing it to liquefy becase it is under pressure. The liquid coming out of the bottom of the condenser is fed automatically into the tinned coil inside the refrigerator by means of an expansion valve, which works intermittently to step down these condenser pressures to a pressure above atmospheric pressure. Moisture abstracted from the refrigerator is deposited on the coil, and freezes because the coil is at 14° F. The machine operates intermittently so that this frost does not accumu- late. On the stand-still period the frost will melt and run off through the drain pipe of the refrigerator. In the ice-making compartment it is possible in warm weather to make 32 cubes of ice in a day of twenty-four hours, automatically. Ice can be made in winter only when the refrigerator is in a well-heated room ; otherwise the ma- chine will run too small a percentage of the time. The complete machine is supplied as a unit readv to run when connected to an electric light socket. The number 1 240 HOUSEHOLD REFRIGERATION size will take care of an ordinary refrigerator not to exceed fifty-five square feet of internal exposed area when set over a hole thirteen inches 1)- thirteen inches in the top of the refrigerator. The actual weight of the apparatus is 175 pounds. Isko — Present Model. — The present model of the Isko ma- 1 ff Oi&gr&m of ISKO Refrigerating Machine ig course o' --cfrigerant FIG. 100.— ISKO REFR]GER.\TrXG M.\CHIXE. chine is shown in Fig. 100. This machine was formerly man- ufactured in large quantities b' the Isko Company at Chicago. The compressor was of the herringbone gear type, operat- ing at motor speed submerged in a sealed chamber of oil. COMPRESSION REFRIGERATING MACHINES 241 The gears were supplied with a small amount of oil to seal them so that they would compress the sulphur dioxide gas, this being the refrigerant used. The cylinder and motor were mounted on a single base to be placed on the top of the refrigerator or in the basement, if desired. The motor was directly connected to the gear shaft through a flexible coupling. Brine tanks were made in various sizes. An expansion \alve was used, expanding into a copper tube immersed in the brine. A small header was used on the suction line between the evaporating coil and the compressor to prevent frosting back to the machine. The condenser was water-cooled by means of a copper coil inside the condenser cylinder. Part of the cooling water circulated through a coil in the compressor cylinder, in order to cool the oil in which the gears operate. Full automatic controls were used to maintain a uniform temperature inside the refrigerator. Kelvinator. — Fig. 101 shows the Model Senior (2 cylinder) refrigerating machine made by the Kelvinator Corporation, Detroit, Michigan. This is a motor-driven refrigerating ma- chine designed for installation with any refrigerator of stand- ard construction of not over 70 cubic feet contents. The condensing unit consists of the motor, compressor, and condensing coil mounted on a single base and is installed in the basement or other out-of-the-way place. The compressor is of the reciprocating, single-acting type. Piston valves and discharge valves are of the disc type. The pistons slide in steel sleeves. Instead of a stuffing box a sylphon gas seal of self-aligning, self-lubricating, anti-friction metal is used. It is driven through a combined flywheel and fan by a "V" belt. The motor is of the repulsion induction type, y^ hp. The condenser is a continuous coil of ^ inch seamless copper tubing wound spirally and charged with sulphur diox- ide. It is air-cooled and therefore is not dependant on any water supply for its proper operation. 242 HOUSEHOLD REFRIGERATION Fig. 102 shows the Model Junior (1 cylinder) refrigerating machine. This is similar to the Model Senior