'122 Mill' and Its Products. 



ble, also, because the bearings are not perfecth' ad- 

 justed ; and, lastly, the bowl may tremble because 

 the machine is not set level or upon a solid founda- 

 tion. A second cause of inefficient separation is 

 variation in the velocity of the bowl. It is quite as 

 important that the bowl run uniformly as it is that 

 it attain any given rate of velocity. In this re- 

 spect the turbine separators are more likely to be 

 at fault than those run by belt power, and separa- 

 tors turned l\v hand are more subject to variations 

 than those run l)y power. 



An engine of ample power, with a good gover- 

 nor, and the power transmitted through an interme- 

 diate rope belt kept perfectly tightened, with well-oiled 

 bearings all around, are the best safeguards to uni- 

 form speed. 



Efficiency of separation in centrifugal machines. — 

 With the centrifugal separator run under perfect con- 

 ditions, there is still a slight loss of fat in the 

 skimmed milk. This need not be greater than .1 

 of 1 per cent. At the present time it is considered 

 that where more than .1 of 1 per cent of fat is left 

 in skimmed milk, a centrifugal machine is not doing 

 perfect w^ork, and numerous trials have shown that 

 the machines of the leading forms can be made to 

 reach this point of efficiency, as may be seen from 

 the following table, "^ giving the average of a large 

 number of tests made by several agricultural experi- 

 ment stations : 



♦Cornell University Agricultural Experiment Station, Bulletin No. 105. 



