188 AGRICULTURE. 



ous stream, while the cream flows from one 

 opening and the skim-milk from another. 



As the milk flows into the revolving bowl, it 

 is acted upon by centrifugal force, and flies to 

 the outside wall of the bowl. The skim-milk, 

 being heavier than the cream, is forced outward 

 with greater force, and seeks the outside of the 

 bowl, forcing the lighter cream toward the cen- 

 ter. Near the outer edge of the bowl are open- 

 ings of small tubes, into which the skim-milk 

 flows and through them passes out of the bowl. 

 Near the center of the bowl is the opening of a 

 small tube, which carries out a constant stream 

 of cream. 



A number of conditions affect the thorough- 

 ness of separation with a centrifugal separator, 

 especially the speed of machine, the tempera- 

 ture of milk, and the rate of inflow of milk. 

 The most favorable temperature for separating 

 milk is from 85 to 100 F. When the temper- 

 ature falls much below 80, the loss of butter 

 fat with the skim-milk begins to increase. Some 

 types of separators are much more sensitive to 

 low temperature than are others. 



The proportion of the milk taken out as 

 cream can be changed in most separators with- 

 out changing the thoroughness of separation 

 by slightly turning what is called the cream 

 screw. By this means most separators may be 

 adjusted to separate from 10 to 50 per cent, of 



