Page:The story of milk.djvu/73

 few minutes when exposed to centrifugal force. From this early crude attempt the continuous bowl-separator was developed and still later a number of divisions in the bowl were designed which increased the capacity and efficiency of the machine wonderfully. The most successful separator was designed by Dr. Gustaf De Laval of Sweden and the machines bearing his name are used all over the world where butter is made. But there are many other excellent separators on the market.

Dr. Gustav De Laval of Sweden, inventor of the separator bearing his name

In the machine the milk is separated instantaneously by centrifugal force and runs out through two tubes, one for cream and the other for skim milk. A small modern hand machine will take care of from 200 to 1,000 lbs. of milk an hour, and power machines are built to separate 6,000 lbs. or more. By regulating the cream-outlet a heavier or lighter cream can be produced.

Hand separator

Suppose we are separating some milk containing 4% butter-fat. If 1/8 of this milk is separated out as cream and contains all the butter-fat, the cream will be eight times as rich in butter-fat as the original milk; 32% of the cream will be butter-fat. Such cream is called "32% cream." If we take 1/4 as cream, we get a