Page:Popular Science Monthly Volume 88.djvu/921

 Popular Science Monthly

��893

��usually rises as high as 150 pounds. With sulphur-dioxide as the refrigerant the pressure in the condenser is rarely over 50 pounds, and the heat generated in compression is also much less than when ammonia is used.

In most of the household refrigerating machines, all parts of the machine, in- cluding the electric motor, are arranged on a bed-frame which rests on top of the ordinary household refrigerator, the expansion or refrigerating-coil extending down into the com- partment usually occupied by ice. This coil may be arranged in a tank containing brine to store up reserve cold for times when the machine is stopped, or the coils may be so arranged as to hold small cans for freezing ice.

In one of the recent sulphur- dioxide machines, shown in the accompanying illustration, the use of cooling water is dispensed with and air-cooling is substi- tuted. In this machine the condenser is composed of a great length of small copper pipe coiled around to form an en- closing fence about the com- pressor and motor. The spokes of the fly-wheel of the com- pressor are arranged at an angle so as to circu- late air over the con- denser-coil. The elimi- nation of the cooling water is obviously a very attractive feature of this machine.

Another household machine, using ethyl- chloride as the circulat- ing refrigerant and em- bodying a rotary com- pressor, is shown at the top of page 894. It is very compactly arranged and is constructed on sound engineering prin- ciples.

Still another household machine uses a low-pressure refrigerant known as the "Barsmith liquid," or "Barsmith gas," having many of the characteristics of sulphur-dioxide. In construction this

��machine consists of a refrigerant con- tainer, an expansion-valve, a brine tank, a compressor, a condenser, and a motor, usually an electric motor. The brine tank is located in what is termed the ice compartment of the refrigerator. The other parts of the machine may be lo- cated on top of the refrigerator. The expansion-valve is connected with the brine tank. The liquid refrigerant passes from the container to the expansion

���COPfen PIPE FENCE £NCLOSIHC COMPR£SS0/> 5 MOro» i

���CONOENiEK COIL

��In this sulphur-dioxide machine the use of cooling water is dispensed with. Instead, a condenser com- posed of a great length of small copper pipe coiled around to form an enclos- ing fence for the motor and compressor is used. The air cooling method employed in this appara- tus is, in many ways, an advance over that of other refrigerating machines

��\al\'r, expands to a gas, and bubbles up through the brine and is collected in a dome on top of the brine tank, from which it is drawn off by the compressor, compressed and cooled and passed back to the container ready for another cycle.

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