108 Milk and Its Products. 
for revolving the bowl. (The more common types of 
separator bowls are shown in Figs. 10-13.) Usually 
the bowl is driven in an upright position, but there 
are separators in which the bowl is driven in a hori- 
zontal position, and in the greater number of ma- 
chines the walls of the bowl are eylindrical. In the 
process of separation the milk flows into the bowl, 
and, partaking of the centrifugal force, is forced to 
the extreme outer edge of the bowl. As the milk 
continues to flow in, the bowl begins to fill from 
the outside toward the center. The centrifugal force 
acting more strongly upon those parts of the milk 
which have the greatest specific gravity, they are 
thrown to the extreme outside, and the hghter por- 
tions, the fat globules, with whatever may adhere 
to them, are forced to the center. Attached to the 
extreme outer edge of the bowl are one or more’ 
tubes, which, bending inward along the side of the 
bowl, find an opening near the center. These are 
the outlets for the skimmed milk. From the ex- 
treme center of the bowl, also leading to the out- 
side, is the cream outlet. When the bowl becomes 
filled with milk, the centrifugal pressure will force 
out through the skimmed milk outlets the milk nearest 
the outside of the bowl. These outlets are made 
of such size in comparison with the size of the bowl, 
the speed of the machine, and the size of the inflow 
tube, that they have a capacity of discharging the 
milk from .4 to .9 as fast as it runs in; the remain- 
ing contents of the bowl are then forced toward 
the center, and find an exit through the cream 
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