APPLICATION OF REFRIGERATION TO HANDLING OF MILK. 45 



in the piping will be 1 .5 X 52 X 16 = 1,248 B. T. U. Consequently the 



1 248 X 16 

 hold-over period due to the brine in the piping is ' .»„ =0.58 



hour. If there are 2,000 pounds of butter stored in the room, it will 



also assist in increasing the time of shut down for a 3-degree rise in 



room and contents. The rise in temperature of the butter for a 



34 400 

 16-hour shut down will be „ ' fl , . . = 31 .3 degrees, or 3 



degrees in 1.53 hours. Therefore, the total time the plant can be 

 shut down for a 3-degree rise in temperature of room and contents 

 is 0.58 + 1.53=2.1 hours. Consequently it becomes necessary with 

 this system to circulate the brine continuously. If, however, a 

 sufficient volume of low-temperature brine is available for circulating 

 through the coils, the refrigerating machine may be shut down for 



Fig. 21. — Elementary diagram of brine storage system. 



a time, depending on the volume and temperature of the brine, by 

 continuing the action of the pump. 



BRINE-STORAGE SYSTEM. 



In place of the continuous brine coils employed in the brine-circu- 

 lating system there is a modified brine system designed to give 

 practically the same results (fig. 21). This is known as the brine- 

 storage system and consists in replacing the main tank by several 

 smaller ones located in the various compartments of the cold-storage 

 plant. With an equipment of this kind the initial cost of the brine 

 pump, the main brine tank, the necessary piping for brine circulation, 

 and the brine-tank insulation are ehminated, as well as the power 

 to operate the brine pump and the radiation losses through the 

 brine tank and pipe insulation. 



The heat-absorbing surfaces of the various small tanks entirely 

 replace those of the brine coils. In practice, however, from one third 

 to two-thirds of the direct expansion coils are placed outside of the 

 brine, in direct contact with the air in the cold-storage room, in 



