180 ■ ILLINOIS STATE DAIRTMEiN'iS ASSOCIATION. 



enougli then yonr rings are leaking or your cylinder needs bor- 

 ing out. 



To find out tlie horse power of any engine, find out the 

 area of the piston head face, then multiply this answer by the 

 average pound pressure per square inch, then multiply this an- 

 sw^er by the number 'of feet traveled in one minute and divide 

 by 33,000, as 33,000 pounds to a square foot is one horse power. 



THE VALUE OF ARTIFICIAL REFRIGERATION. 



H. H. HOPKINS, HINCKLEY. 



Mr. President, Ladies and Gentlemen : 



I have been assigned the subject of "Artificial Refrigera- 

 tion." The production of cold by the Compression System 

 is accomplished by the compression, condensation and expan- 

 sion of ammonia gas in continuous operation. 



The compressor is a pumping engine especially designed 

 to compress ammonia gas and force it through the pipes of 

 the condenser, under a pressure, varying according to the 

 temperature of the water. 



The condenser is a system of pipes submerged in cold 

 water, the heat produced by the compression of the ammonia 

 gas is absorbed by the cold water surrounding the pipes, when 

 the gas becomes liquified and is then in proper condition to 

 do the work of refrigeration. 



Continuous coils of pipes are placed in the room to be 

 cooled and also a brine tank varying in size according to the 

 size of room. The pipes on the side of the room is what is 

 known as the direct expansion system, while the coils placed 

 in the brine tank is a part of what is known as the brine storage 

 system. 



I think a combination of the two systems is better for the 

 creamery business, than to use only one system, because the 

 direct expansion system can be used to cool water, milk or 

 cream by passing over coils in which the liquified ammonia 

 gas is fed and a coil placed in room to be cooled will help 

 the temperature of the room, while a coil in a brine tank will 



