58 CREAMERY BUTTER MAKING 



of the country this practice is actually growing. Cream 

 thus gathered is, however, largely the product of the 

 cream separator, only a small portion being still creamed 

 by the gravity process. The discussion on creaming will 

 therefore be confined to the centrifugal process. 



CREAM SEPARATORS. 



History. The cream separator had its beginning in 

 1864 when Prandtl, of Munich, creamed milk by means 

 of two cylindrical buckets revolving upon a spindle. In 

 1874 Lefeldt constructed a separator with a revolving 

 drum similar to the later hollow bowl separators. This 

 drum had a speed of 800 revolutions per minute. But 

 it lacked an arrangement permitting a continuous 

 discharge of cream and skim-milk, so that the separator 

 had to be stopped at regular intervals when the cream 

 was skimmed off, the skim-milk removed, and the bowl 

 refilled for the next separation. 



It was not until 1879 that real separators appeared 

 upon the market. During this year two machines were 

 perfected which permitted continuous cream and skim- 

 milk discharges. One was known as the Danish Weston, 

 invented in Denmark, the other the De Laval, invented in 

 Sweden. Both of these separators were hollow bowl 

 machines. 



Other separators soon followed but no decided improve- 

 ment was made until 1891, when the De Laval separator, 

 shown in Fig. 18, appeared with a series of discs inside 

 the bowl which had the effect of separating the milk in 

 thin layers, thus increasing both the efficiency and the 

 capacity of the separator. Since then various bowl devices 

 have been invented by numerous separator manufacturers. 



