FRUIT STORAGE 1Q5 



Mechanical Refrigeration. Space and time will not 

 permit going into this subject in detail, but it seems best 

 to give a general idea of how cold storages are oper- 

 ated under the mechanical systems. Of these there are 

 two general types: the first and older one is known as 

 the air compression system. This was originally installed 

 on ocean steamships where large quantities of stored 

 food products had to be carried. It consisted simply of 

 compressing the air under pressure until the heat was re- 

 moved and then discharging it direct into the storage 

 room. As the air expands, heat is taken up from the 

 room, thereby keeping the temperature lowered. 



This method is still in use in some places but has 

 largely been discarded because of the high cost of oper- 

 ation. The other method, and the one now in most 

 common use, is the ammonia compression system. In 

 this an ammonia solution is used because it will liquify 

 under much lower pressure than air. Large costly ma- 

 chinery of special make is required to operate such a 

 system. 



Ammonia Compression System 1 . "The production 

 of cold by this system is accomplished by the expansion 

 or evaporation of liquid anhydrous ammonia. The sys- 

 tem consists of three essential parts, the compressor, 

 the condenser, and the expansion coils. 



The Compressor. "The compressor is a pumping 

 engine especially designed to compress the ammonia gas 

 and force it through the pipes of the condenser, under a 

 pressure, varying according to the temperature of the 

 condensing water from 150 to 185 pounds per square 

 inch. 



1 Remington Machine Company, Wilmington, Del. 



