190 Milk and Its Products 



bowl run uniformly as it is that it attain any given 

 rate of velocity. In this respect the turbine separators 

 are more likely to be at fault than those run by belt 

 power, and separators turned by hand are more subject 

 to variations than those run by power. 



An engine of ample power, with a good governor, 

 and the power transmitted through an intermediate rope 

 belt kept perfectly tightened, with well-oiled bearings 

 all around, are the best safeguards to uniform 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 should not be greater than .1 

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

 that where as much as .1 of 1 per cent of fat is left 

 in the skimmed milk a centrifugal machine is doing 

 such poor work that its use in a commercial plant would 

 be unwarranted. The following tables* taken from the 

 average of a large number of tests made by several agri- 

 cultural experiment stations may be taken as repre- 

 senting the degree of efficiency that had been attained 

 by the leading manufacturers at the time when separa- 

 tors first came into general use (1890-95) and the first 

 table is compiled wholly from American sources. At 

 the present time no separator should be kept in use 

 that will leave more than two or three hundredths of 

 one per cent of fat in the skimmed milk in a series of 

 tests running day after day under ordinary factory 

 conditions. 



*Cornell University Agricultural Experiment Station, Bi;lletin No. 105. 



