284 F. E Nipher — Non-condensing Steam Engine. 



value of b is changed in order to change mean effective pres- 

 sure. In a governor which varies the cut-off, both E and b are 

 changed by the action of the governor. 



The action of any governor changes the inclination of the 

 line VB, in fig. 1. For a constant boiler pressure P\ if the 



Fig. i. 



cut-off comes earlier, or, if the steam is throttled, the line VB' 

 becomes less steep, and the points p' and p" sink to represent 

 a smaller output.* In fig. 2, the action of the governor 

 changes the position of the line w — o, and in fact the entire 

 surface of HP as function of P '. 



Making the indicated substitutions in (6) 



^ + ^o+ 



P' = -h- 



R'l 



(A_|-Po+£-H&-fc)n) 



h+P« 



Solving this equation for w. 



Multiplying (9) by 



i+P o + £I+(b+c)i 



27tnr 

 33000 



(8) 



(9) 



* In an experimental engine the head of the screw which controls the steam 

 should be provided with a divided scale like a micrometer. 



