290 CREAMERY BUTTER MAKING 



so set on the valve stem that its edges will pass each 

 steam port an equal amount during a full revolution of 

 the engine. If not so set, the valve should be moved, by 

 loosening the nuts on the valve stem, until the correct 

 position is reached. 



The next thing to do is to place the engine on its true 

 center with the outward stroke. Now turn the eccentric 

 upon the shaft in the direction in which the engine is to 

 run until the valve has uncovered the port sufficiently for 

 the required lead, which should be about one-sixteenth 

 of an inch. 



Governor. This device governs or regulates the speed 

 of the engine by controlling the inlet of steam in to the 

 cylinder. 



There are two kinds of governors : one is known as the 

 automatic cut-off which consists of centrifugal weights 

 placed in the fly wheel, which vary the point of cut-off 

 by revolving the governor eccentric upon the shaft. With 

 governors of this kind the steam is entirely cut off when 

 the speed gets too high, while with the other form of gov- 

 ernor the steam is throttled. The "throttle" or "ball" 

 governor is more common on creamery engines than the 

 automatic cut-off. Fig. 83 illustrates the working of the 

 ball governor. The important parts are : i , governor 

 balls ; 2, pulley ; 3, stem ; 4, valve discs ; 5, stuffing box ; 

 and 6, valve seats. As the speed of the engine increases 

 the balls are thrown farther out and the valve discs come 

 nearer the valve seats, thus throttling or reducing the 

 amount of steam that enters the cylinder. 



The automatic cut-off is considered the more economi- 

 cal of the two governors though it is somewhat more 

 difficult to regulate. Most engines now made are of the 

 automatic cut-off type. 



