THE PASTEURIZATION OF MILK 



Another point to be observed when partitions 

 separate the tanks is to make sure that no tank 

 becomes filled to overflowing. In such case, the 

 milk will flow into a tank from which milk is be- 

 ing discharged, and thus the holding time becomes 

 a matter of great uncertainty. 



In this form of holder considerable foam de- 

 velops, due to the dropping of the milk for a con- 

 siderable distance from the discharge pipe into 

 the body of milk in the tanks. The foamy milk 

 does not retain the heat as well as is desirable, 

 and as a consequence the destruction of the bac- 

 teria is not always sufficiently complete. 



In Fig. 21 the eight compartments or wells are 

 themselves immersed in a tank of water, the tem- 

 perature of which is kept somewhat above that to 

 which the milk is heated. In this form of appa- 

 ratus the tendency to foam is largely overcome 

 from the arrangement which allows the milk to 

 enter the well from the bottom. Both the inlet 

 pipe and the outlet pipe are operated by means of 

 mechanism, which is above the tanks. There are 

 sixteen valves, each of which is made tight by a 

 ground seat, upon which the valve sets. These 

 valves are at the lower end of the plug shanks, 

 98 



