SIR WILLIAM SIEMENS, F.R.S. 159 



/// the discussion of the Paper 



"ON THE ALLEN GOVERNOR AND THROTTLE- 

 VALVE FOR STEAM-ENGINES," 



By Mr. FREDERICK "W. KITSON, 



The I'KKSIDKXT (MR. C. W. SIEMENS)* said he considered the 

 ; \vrnor described in the paper was remarkable chiefly for its 

 simplicity, and it appeared to have been found to answer well in 

 jirartice. Reference having- been made to his own liquid governor 

 in (( innection with that now described, it was to be observed that, 

 though both of them dealt with liquid resistance, they did so in a 

 different manner. 



In the governor now described the power to act upon the throttle- 

 val\v was obtained in an indirect way ; the rotating paddle-wheel 

 did not act directly upon the valve, but impelled the oil against the 

 corrugations in the casing containing it, and the impact tended to 

 make the casing rotate in the same direction ; the casing however 

 was held back either by a dead weight, or, as had been suggested, 

 by a spring, or really by a combination of a dead weight and a 

 spring, because a weight alone would overrun itself if acting at a 

 constant leverage. When therefore the velocity of the rotating 

 paddle-wheel was so proportioned to the weight as just to hold 

 the latter suspended, a balance was established ; but as soon as 

 the engine exceeded its normal speed, an additional amount of 

 impact was created in the oil casing, which accumulated until it 

 had sufficient power to overcome the resistance of the throttle- 

 valve and of the stuffing-box on the valve spindle. This power 

 however to move the valve was not large, in comparison with the 

 total force acting to support the governor weight at the normal 

 speed ; if for instance 100 revolutions of the paddle-wheel per 

 minute sufficed to balance a weight of 10 Ibs., then a variation in 

 I of two or three revolutions per minute would affect the weight 

 to the extent of only a small fraction of a pound, which would 



* Excerpt Minutes of Proceedings of the Institution of Mechanical Engineers 

 1873, pp. 60-62. 



