92 SKIMMING EFFICIENCY OF THE: SEPARATOR 



machine, causing the separator to be run at too low a speed, 

 thereby not getting out of the milk all the available fat. This 

 is particularly true where different persons operate the same 

 machine, but even the same operator, unless he times himself, 

 may soon get in the habit of running the machine too slowly. 



The metronome, which can be set to tick the exact number 

 of turns required per minute is a very useful instrument to keep 

 up the speed of the separator. 



Some separators have a bell attachment striking the re- 

 quired number of revolutions per minute when the separator 

 runs full speed. 



The gyrometer is another separator speed indicator which 

 is extensively used in European machines. It consists of a 

 graduated glass tube, partly filled with glycerin and closed at 

 both ends. It is either directly or indirectly connected with 

 the spindle of the bowl, so that it revolves with the spindle. 

 When revolving, the glycerin, acted upon by the centrifugal force, 

 recedes from the center, rises along the walls of the tube and 

 forms a funnel of air in the center, the length of which bears 

 a definite relation to the speed of the machine. A graduation 

 on the tube extending from top to bottom, shows the number 

 of revolutions of the bowl at different lenghts of the air funnel. 



In more recent years in this country numerous types of 

 speed indicators, attached to the machine and operating on a 

 principle similar to that of the speedometers used on automo- 

 biles, have been devised and are in more or less general use. 

 One of the more recent ideas of speed indicator is a combina- 

 tion of speed governor and controller of the rate of inflow of 

 the milk. Its fundamental idea is to reduce the milk inlet as the 

 speed of the machine drops below normal, and thereby automatic- 

 ally maintain the skimming efficiency at a speed below normal, 

 the decreased skimming efficiency of the lower speed being offset 

 by the increased skimming efficiency of the reduced milk inflow. 



The principle of regulating the rate of inflow by the speed 

 and thus maintaining the skimming efficiency at a reduced 

 speed has been applied in the case of the Sharpies Tubular 

 separator. In the latest models of this machine the rate of 

 inflow is dependent on the suction generated by the revolving 



