VARIATION OF FAT IN CREAM 



87 



curate testing when the separator float is a conspicuous part of 

 the scrap pile on the farm. 



4. Effect of Speed of Machine on Richness of Cream. The 

 speed of the revolving bowl produces the force centrifugal force 

 which drives the skim-milk out of the bowl. The greater the 

 speed, the greater the centrifugal force and the more rapidly 

 the skim-milk leaves the bowl. An increase in the speed, there- 

 fore, forces more skim-milk through the skim-milk outlet. 

 This means less milk for the cream outlet and consequently 



EFFECT OF SPEED UPON THE RICHNESS OF CREAM 



NORMAL SPEED 



1OO LBS. OF 4.4$ MILK 

 DREAM CONTAINS 4.4 LBS. FAT 



90 LBS. 



SKIM-MILK 



10 LBS. CREAM CONTAINS 

 4.4 LBS. FAT 



TEST OF CREAM 



LOW SPEED 



OO LBS. OF 4.4$ MILK 

 CREAM CONTAINS 2.-1 LBS.FAT 



81 LBS. 

 SKIM-MILK 



19 LBS. CREAM CONTAINS 

 1 LBS. FAT 



TEST OF CREAM =11$ 



100.11* 



HIGH SPEED 



1OO LBS. OF 4.4# MILK 

 CREAM CONTAINS 4.4 LBS.FAT 



7 CBS. CREAM 



93 LBS. 

 SKIM-MILK 



TEST OF CREAM =63 # 

 ^1 x 100 =63$ 



FIG. 16. 



richer cream. A decrease in the speed forces less skim-milk 

 through the skim-milk outlet, more milk has to be discharged 

 through the cream outlet and the cream, therefore, is thinner. 



These facts were established experimentally. A separator 

 was so adjusted that, when run at normal speed (60 turns of 

 crank per minute), it delivered 90 pounds of skim-milk and 10 

 pounds of cream. When the speed was lowered to 25 turns of the 

 crank per minute, the skim-milk outlet discharged only 81 pounds 

 of skim-milk, increasing the amount of cream delivered to 19 

 pounds. When the speed was raised to 75 revolutions per 

 minute, the skim-milk discharge increased to 93 pounds, reducing 



