CHAPTER V 



REFRIGERATION 



One of the chief requirements in any creamery is adequate 

 means for keeping the products it handles properly cooled. Re- 

 frigeration may be brought about either by a natural or by a 

 mechanical system. In either case, however, it is essential that 

 cooling rooms and cooling tanks are properly insulated. 



INSULATION 



A thermic insulator is anything which prevents or retards 

 the transmission of heat. As applied to a creamery, insulation 

 means the separation of its storage rooms from outside tempera- 

 tures by non-heat-conducting walls, ceilings, floors, windows and 

 doors. The insulator conserves refrigeration which has been 

 created through natural or artificial means; hence, the slower 

 its powers of heat transmission, the better the insulator will be. 

 Any rules of guidance for effective insulation must, therefore, 

 be based on the principles of heat transmission. 



Transmission of Heat. — Heat may be transmitted in three 

 ways: 



1. By Radiation. — Heat is transferred from one body to an- 

 other where the temperature of the intervening medium remains 

 unaltered. This form of transmission is of less importance in 

 considering the subject of insulation. 



2. By Convection. — Heat is transferred by convection when 

 it is carried from one point or object to another by means of 

 some outside agent as air, water, or any gas or fluid; thus heat 

 may be removed from a cold-storage room by the brine method 

 of refrigeration. In the case of a refrigerator wall with large 

 air space, the face next to the outer air is warmer than the face 

 next to the cold room. In the air space, the air against the 



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