80 CENTRIFUGAL SEPARATION 



Separators with bowls which discharge both, their milk and 

 cream at the top of the bowl, are equipped with a cream and a 

 skim milk catch pan with discharge spouts. These pans lie on 

 the separator bowl frame. The top pan discharges the cream, 

 the bottom pan the skim milk. In the case of separators which 

 discharge their skim milk from the bottom of the bowl, no skim 

 milk discharge pan is needed, the skim milk escaping through a 

 tube in the frame at the bottom of the bowl. 



The Driving Mechanism. The parts of the separator which 

 control the transmission of the motive power, differ with the 

 type of motive power used. The earlier machines were all 

 factory separators which were driven either by belt, or steam 

 turbine and later by electricity. 



The mechanism for the transmission of the power which 

 revolves the bowl differs fundamentally between power or 

 factory separators and hand separators and to some extent as to 

 the type of power used. Differences in the details of the arrange- 

 ment of the transmission further occur between separators of 

 the same type but of different makes. 



Power or Factory Separators. The first centrifugal separa- 

 tors were those used in the factories and which are operated by 

 power. The factory machines, as far as the type and mechanism 

 for the transmission of the motive power is concerned, may be 

 divided into belt machines, turbine machines and electric-driven 

 machines. 



In the belt-driven machines the power is generated by a 

 separate engine or motor which is entirely independent of "the 

 separator and, as far as the operation of the separator is con- 

 cerned, is connected with the separator only when the latter is 

 to be operated. In this case the motive power may be generated 

 by a steam engine, a gasoline engine, electric or water motor. 

 In the creamery where the steam engine, or possibly the elec- 

 tric motor, is a necessary part of the equipment for the operation 

 of various lines of power machines, such as churns, pasteurizer, 

 etc., the separator is usually connected by belt with the main 

 shaft or line shaft. In the case of separators of small capacity, 



