330 THE HANDBOOK FOE PRACTICAL FAEMERS 



in determining the size of separator that will meet the require- 

 ments of the herd it is well to remember that the herd mil prob- 

 ably increase from year to year, and purchasing a separator 

 Avith a slightly larger capacit}'^ than is actually needed at pres- 

 ent will save the dairyman buying a new and larger machine 

 later on. 



Principle of centrifugal separation. — The centrifugal sep- 

 arator separates the cream from the skim milk by centrifugal 

 force. This is made possible by the fact that the skim milk par- 

 ticles are heavier than the fat particles. The milk on entering 

 the rapidly revolving separator bowl is forced to the outside of 

 the bowl. As the skim milk particles are the heaviest they are 

 thrown against the bowl walls, displacing the lighter fat glob- 

 ules and forcing them back toward the center, where they are 

 drawn off as cream. The skim milk is collected from the outside 

 of the bowl and removed through another channel. 



CARE OF THE CREAM SEPARATOR 



The cream separator is generally placed in the milk house or 

 other room where the milk will not be exposed to odors and bad 

 air while in course of separation. As most separators run at a 

 high speed, they should be firmly secured to a solid floor or foun- 

 dation in order to prevent vibration. If the separator is not so 

 secured the frame will vibrate and cause the bowl to wabble. 

 Under such conditions the separation of cream from the milk is 

 not complete and considerable butter fat is left in the skim milk. 



Foundation for the separator. — The cement floor is the best 

 type of floor for the separator, as it does not vibrate and is easily 

 kept clean and free from odors. If the machine is to be set upon 

 cement, bolts should be embedded in the floor with enough of 

 the threaded end exposed to allow washers and a nut. Space for 

 the washers is jorovided so that they may be added or removed 

 in leveling up the machine. If this method is used, careful meas- 

 urement should be made to get the bolts exactly in the right 

 place, for an error of a small fraction of an inch may necessitate 

 resetting one or more bolts. 



Good results have also been obtained by setting two four-by- 

 four's or other solid timbers in the cement about where the base 

 of the separator is to rest. Lag screws are then used to secure 

 the separator to the timbers. 



"Where the floor is already laid, holes may be drilled, the bolts 

 inserted, and hot lead poured into the holes until even with the 

 surface of the cement. 



