72 



CENTRIFUGAL SEPARATION 



being left in the center. The vertical wall of milk in the bowl 

 increases until the discharge from the skim milk outlet and that 

 from the cream outlet equal the rate of inflow of milk to the bowl. 



The intensity of the centrifugal force is controlled by three 

 fundamental factors ; namely the speed and diameter of the bowl 

 and the weight of the contents. It increases in proportion as the 

 weight of the contents of the bowl and the diameter of the bowl 

 increases, and also with the square of the number of revolutions 

 per minute. Lamson 1 calculated the centrifugal force factor for 

 numerous farm separators as shown in the succeeding table. 

 His calculations are based on the following formula: 



Fc=WD (R. P. M.) 2 .000014208 in which 



Fc= Centrifugal force 



W= Weight expressed in pounds 



D=Inside diameter of bowl expressed in inches 



R. P. M.=Revolutions per minute. 



In all of the computations, the weight was figured as one 

 pound, since a comparison only of the centrifugal force factors 

 was desired. 



Table 4. Centrifugal Force Factor when Revolutions per Minute 

 and Diameter of Separator Bowl in Inches are known. 



1 Lamson. A Study of Farm Separators. M. S. A. Thesis, Purdue Uni- 

 versity, 1918. 



