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. 



