THE PASTEURIZATION OF MILK 



pipe from the heater enters the tank at the centre 

 of the bottom, and the milk is forced upward till 

 the tank is filled, the color tests made have indi- 

 cated that their efficiency percentage was small. 

 Especially was this true when the outlet pipe was 

 at one side and near the top of the tank. It can 

 be seen that the force which is necessary to impel 

 the milk in at the bottom against the weight of 

 the superimposed milk in the tanks must of neces- 

 sity create currents. This will be more noticeable 

 if the milk is forced through the heater by means 

 of a pump. The impulses will create a somewhat 

 uneven flow and the resulting currents will be 

 greater. The discharge of the milk from one side 

 of the top also tends to cause currents and an 

 uneven overflow. 



One manufacturer has so constructed his tanks 

 that the inlet pipe enters at the top through the 

 cover, is carried down through the body of the 

 milk in the tank to the bottom, and then dis- 

 charges the milk into the tank by means of an 

 enlarged perforated foot somewhat resembling a 

 sprinkler head on a watering can. In the plants 

 where this apparatus is used the milk flows by grav- 

 ity and there are thus no pump impulses. The 

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