CENTRIFUGAL SEPARATION 81 



not over about 2,000 pounds of milk per hour, the belt from the 

 shaft usually connects direct with the separator. The lower 

 end of the spindle of the separator is geared to a short horizontal 

 shaft which carries a tight and a loose pulley. In order to start 

 the separator slowly and to avoid sudden jars when changing the 

 speed of the engine, the belt is shifted from the loose to the 

 tight pulley very gradually. This type of power transmission 

 is suitable also for large dairy farms where a gasoline engine or 

 similar power is available. It has the advantage of facilitating 

 the maintenance of uniform speed, provided that the belt does 

 not slip, and of utilizing steam or other power and space 

 economically. 



For machines of larger capacity, such as are used in the 

 average commercial creamery and which may range as high as 

 10,000 pounds of milk per hour or higher, indirect transmission 

 of the belt power is used. For this purpose a double trans- 

 mission in the form of an intermediate, or jack, is installed. The 

 intermediate consists of a tight and loose pulley to which the 

 pulley on the main shaft is belted and a large wheel which trans- 

 mits the power from the intermediate to the separator by means 

 of an endless separator cord or strap. In order to take up the 

 slack in the cord the intermediate is equipped with a weighted 

 lever which presses against the cord while in operation, tighten- 

 ing the latter and preventing excessive slipping. The inter- 

 mediate rests on an independent standard, permanently erected 

 and usually at a distance of about 12 feet from the separator. 

 The chief disadvantage of the use of the intermediate is that it 

 takes up considerable space which might be utilized for other 

 purposes. In the latest of models of power separators the inter- 

 mediate has been dispensed with, removing the above objection. 



In the steam turbine-driven separators, in most cases, the 

 lower end of the spindle carries a turbine wheel, which revolves 

 in an inclosed turbine chamber of the separator frame and which 

 contains a reduced steam inlet and a steam exhaust. In separa- 

 tors with pending bowls the turbine is located above the separa- 

 tor bowl. The steam supply pipe is equipped with a valve to 

 regulate the steam inlet and for safety's sake it should carry, 



