114 Milk and Its Products. 
rious contrivances have been introduced in the bowl 
to aid in the completeness of the separation or to 
inerease the capacity. These contrivances have been 
of two general types: one to break up the wall of 
milk, and so give the particles of milk and cream 
a better chance to pass by one another in their 
passage from the center to the outside of the bowl; 
the other, a series of interruptions to the passage 
of the milk from 
its entrance 
at the center 
to the outside, 
causing it to 
travel a much 
greater dis- 
tance and be 
subjected to the 
centrifugal force 
for a longer 
time. These 
contrivances, 
while adding to 
the complexity 
of the machine, 
have increased 
the capacity 
Fig. 12. Section of separator bowl of ‘'United and the e ffi- 
States’ type. 
ciency of the 
separation. The best known of these contrivances 
are the so-called “Alpha” discs or plates,—a series 
of cup-shaped plates, nearly filling the bowl of the 
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