96 



SKIMMING EFFICIENCY OF THE SEPARATOR 



ness of the cream. Undue crowding of the machine and of 

 sacrificing skimming efficiency due to the pressure of the milk 

 above the bowl frequently occurs however, when the separator 

 is fed direct from a vat or tank, through a faucet, as is often 

 the case in the factory, when the supply vat may be located 

 at a considerable elevation above the separator, or possibly on 

 the second floor. 



Effect of Temperature of Milk on Skimming Efficiency. 

 Exhaustive skimming requires the temperature of the milk to 

 be near that of the animal body. There is not much difference 

 in the skimming efficiency between 80 and 100 degrees F. but 

 when the temperature drops to 70 degrees F. or lower, there 

 is a decided, excessive loss of butter fat in the skim milk. 



This phenomenon is probably largely due to the increase 

 in the viscosity of the milk as the temperature drops. The 

 warmer the milk the more fluid it is and the greater the free- 

 dom with which the fat globules can move about. The more 

 fluid the milk the more complete is the separation. With a 

 lowering of the temperature the milk becomes less fluid, its 

 viscosity becomjes greater, the fat globules find more resistance 

 and do not respond to the centrifugal force as readily. 



Table 8. Effect of Different Temperatures on the Per Cent 

 of Fat in Skim Milk. 



