90 SKIMMING EFFICIENCY OF THE: SEPARATOR . 



The formation of a wall of separator slime on the bowl wall 

 reduces the diameter and thereby diminishes the centrifugal 

 force, which, in turn, decreases the rapidity with which the milk 

 passes through and out of the machine. The accumulation of 

 foreign matter and clots also tend to diminish the size of the 

 outlets and partly block the passage of skim milk and cream. * 



CONDITIONS AFFECTING THE SKIMMING EFFI- 

 CIENCY OF THE SEPARATOR. 



The exclusive purpose for which the cream separator has 

 been devised is to skim milk. In its construction, efficiency to 

 skim close was the dominant aim. This skimming efficiency 

 has been accomplished to a very marked degree, removing from 

 96 to 98 per cent of the fat of the milk and leaving in the skim 

 milk less than .1 per cent fat under normal conditions. Experi- 

 ments with the farm separator have "shown even greater skim- 

 ming efficiency when operated under proper conditions. 



In order to accomplish high skimming efficiency and to 

 leave the minimum amount of fat in the skim milk, the machine 

 must be operated properly and in accordance with the directions 

 furnished by the manufacturer. The chief factors which con- 

 trol the skimming efficiency of the cream separator are : Speed 

 of machine, rate of milk inflow and temperature of milk. In 

 addition to these fundamental factors, other conditions such as 

 adjustment of cream screw, smoothness of running, cleanliness 

 of separator bowl and condition of milk, may influence to some 

 extent the per cent fat lost in the skim milk. 



Effect of Speed of Separator on Skimming Efficiency. The 



speed of the revolving bowl generates the centrifugal force 

 which causes the separation of the liquids of different specific 

 gravities, it separates the fat from the skim milk, causing the 

 separator to discharge cream and skim milk. 



The higher the speed, the greater is the centrifugal force 

 and, other conditions remaining the same, the more corpplete 

 is the separation. Every cream separator has a given, rated 

 speed at which it will do its most efficient work. If the speed 

 is reduced below that required, the skimming efficiency will 



