54 DAIRYING 



If a separator has a capacity of 600 pounds per hour and 

 leaves .1% fat in the skim milk, a reduction of 10% in the capac- 

 ity or to 540 pounds, may cause a 10% drop in the test of the 

 skim milk or from .1% to .09% fat, but an increase ' of 10% in 

 capacity, or to 660 pounds, makes more than a 10% increase in 

 the test of the skim milk. It will probably test .15% instead of 

 .11% fat, and a further increase to 720 pounds will raise the test 

 of the skim milk more than 20%, probably to .2% rather than to 

 .12% fat. 



321. The amount of milk running 1 into the separator is usu- 

 ally regulated by a float under the faucet in the milk supply pan, 

 and this should always be used, as it feeds the milk into the sepa- 

 rator at the rate designed by the manufacturers for giving the 

 best results. 



The effect of a variation in the capacity of a separator is 

 shown by the following figures* taken from six skimming trials 

 in each case : 



Per Cent. Fat in Skim Milk 



Normal amount of milk 02 to .035, average .028 



Above normal 13 to .165, average .145 



Below normal 02 to .035, average .027 



322. The capacity of a separator bowl may be changed by 

 the accumulation of dirt and slime as the skimming progresses.! 

 This fills the bowl and naturally reduces the amount of milk the 

 bowl will hold. If there is .05% of dirt and slime in milk and a 

 separator bowl when filled holds three pounds, and further if milk 

 is passing through the bowl at the rate of 600 pounds per hour, 

 there will be accumulated .05%' of 600 pounds or .3 pound dirt 

 and slime per hour, and this is 10% of the three pounds, or the 

 capacity of the bowl is reduced 10% per hour while skimming 

 such milk. 



323. When the bowl is clean, milk passes through it at 

 the rate of 10 pounds per minute (600 pounds per hour), and if 

 the bowl holds three pounds then the milk remains in the bowl 



*Indiana Experiment Station Bui. 116. 

 IKirchner Milchwirtschaft. 



