PRINCIPLES OF NAVAL ENGINEERING 



TOP SHUTOFF VALVE 



GENERATOR IKKER TUBE 



GENERATOR OUTER TUBE 



COPPER TUBE END 

 AT GENERATOR 



INNER TUBE COOLING 

 FINS 



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Figure 11-37.— Single-element feed water regulator. 



the position of the vane in a nozzle-and-vane 

 assembly located in the transmitter. 



A set point knob is linked in some way to 

 the nozzle of the nozzle-and-vane assembly, so 

 that the setting of the set point knob affects the 

 position of the nozzle. The set point knob is 

 positioned to represent the desired temperature 

 of the hot water output. 



The nozzle-and-vane assembly is the com- 

 paring and computing device in this pneumatic 

 transmitter. Since the position of the Bourdon 

 tube affects the position of the vane and the 



setting of the set point knob affects the position 

 of the nozzle, the distance between the nozzle 

 and the vane at all times represents a compari- 

 son of the actual measured value (Bourdon tube) 

 and the desired value (set point knob). The 

 distance between the tip of the nozzle and the 

 vane is responsible for the computation of the 

 amount and direction of change that must be 

 made in the position of the steam valve, since: 



(1) the rate of air flow from the nozzle de- 

 pends upon the distance between the nozzle and 

 the vane; and 



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