118 Milk and Its Products. 



the milk passes so rapidly through the machine that 

 the separation is not complete, and if we reduce the 

 inflow to such a point that the skimmed milk outlet 

 has a capacity of discharging the milk as fast as it 

 flows in, we shall get a separation until the bowl 

 l)ecomes filled, and then all of the milk will pass 

 out of the skimmed milk outlet in the same condi- 

 tion in which it enters the machine. 



The speed of the machine, also, affects the rela- 

 tive amount of cream and its percentage of fat. The 

 size of the skimmed milk outlet being fixed, the 

 faster the bowl is revolved the greater the capacity 

 of this outlet will be, so that, the rate of inflow 

 remaining uniform, the faster the bowl is revolved 

 the less proportional amount of cream we shall have, 

 and the richer it will be in fat, and vice versa. It 

 must be borne in mind, further, that the speed of 

 the bowl is also an important factor in the complete- 

 ness of separation, and that if the speed is slackened 

 in order to get a greater bulk of cream, there will 

 be danger of incomplete separation. 



Most of the machines have arrangements for reg- 

 ulating the relative amount of skimmed milk and 

 cream without changing the rate of inflov*^ or the 

 speed of the machine. In most of the machines 

 this arrangement is known as a "cream screw," and 

 affects the amount of cream by placing the cream 

 outlet nearer or farther from the center of the bowl; 

 the nearer the center the cream screw is turned, the 

 thicker will be the cream and the smaller the amount. 

 Some of the separators change the proportion of 



