78 BULLETIN 98, U. S. DEPARTMENT OF AGRICULTURE. 



receiving tank through some form of cooler to the bottler, where it 



arrives at about 45° F., after which it goes to the storage room. The 



refrigeration in the storage room is obviously the same as in the 



pasteurizing plants. 



The refrigeration necessary to reduce the temperature of the milk 



from 60° to 32° F. is 1,000X8.6X0.95 (60-32) =228,760 B. T. U. 



The heat coming through the floors, walls, and ceiling is the same as 



before. Therefore the total amount of refrigeration required in 24 



hours, allowing 50 per cent for opening doors, presence of workman, 



532 644 

 poor workmanship, etc., is " ; =1.85 tons, or to do the work in 



.£oo,000 



eight hours the size of the machine required is 1.85x3 = 5.55 tons. 



The volume of brine required to cool the 1,000 gallons of milk with 



u- ■ ■ 228,760-133,200 1QO _ ,. ... -- , . 

 machine running is — =^-r = 122.5 cubic feet. The heat 



/oU 

 that will come through the walls, floor, and ceiling is ■ ~ ' . = 



84,224 B. T. U. The rise in temperature of brine and milk will be 



84,224 

 254.5X56.7 " 



In figure 35 (p. 79) are shown curves of the approximate size and cost 

 of belt-driven refrigerating equipment for various sized milk plants. 



REFRIGERATION IN CREAMERIES. 



GENERAL. 



In the application of mechanical refrigeration to creameries the 

 first method employed for cooling cream was to allow it to run over 

 a cream cooler on the way from the separator to the cream vat. 

 This method allowed the cream to be exposed to the air and its con- 

 taminating influences; besides, there was no way provided for hold- 

 ing the cream at a constant temperature after it had reached the vat. 



The next step was to place the brine piping in an open cream vat. 

 This caused unequal temperatures in the cream and prevented the 

 ripening process from going on at a uniform rate, as that portion of 

 the cream in close proximity to the cooling pipes was chilled down 

 considerably below that at some distance from the pipes. The 

 cream was still exposed to the atmosphere, however. Consequently 

 this method was finally discarded. 



Then followed the method of locating the brine or ammonia piping 

 in the water space surrounding the vat, but with this arrangement, 

 as in the foregoing, it was necessary to stir the cream occasionally 

 in order to equalize the temperature of the mass. This method was 

 an improvement, however, as the piping submerged in the jacket 

 water became coated with ice and after the circulation of brine or 

 ammonia had been discontinued the ice would melt and maintain a 



