Question 250General Subjects - Assistant Engineer70% to pass
Suppose the illustrated self-contained, internal-pilot, piston-operated temperature control valve is part of the temperature control system for a steam-heated heavy fuel oil service heater for a steam boiler. If there was a decrease in demand for fuel by the boiler, what statement correctly represents how the valve would initially respond? Illustration GS-0045
AI Explanation
The correct answer is D.
If there is a decrease in demand for fuel by the boiler, the fuel oil heater fuel outlet temperature would increase. This increase in temperature would cause the remote bulb pressure to increase, and the control diaphragm would flex downward. Through lever action, this would further close the pilot valve, reducing the flow of fuel to the heater and maintaining the desired temperature.
The other options are incorrect because they do not correctly describe the response of the valve to a decrease in fuel demand. Specifically, options A and B describe the valve opening further, which would be the opposite of the correct response, and option C describes the diaphragm flexing downward, which is also incorrect.
Related Questions
#248 How would the illustrated valve respond to a complete loss of charge from the remote bulb-to-control diaphragm power element if the valve is used as a temperature control valve for a steam-heated heavy fuel oil service heater? Illustration GS-0045 #249 In the illustrated self-contained, internal-pilot, piston-operated steam pressure- reducing valve, what statement is true concerning the pilot and main valves? Illustration GS-0044 #251 Suppose the illustrated self-contained, internal-pilot, piston-operated temperature control valve is part of the temperature control system for a steam-heated heavy fuel oil service heater for a steam boiler. If there was an increase in demand for fuel by the boiler, what statement correctly represents how the valve would initially respond? Illustration GS-0045 #252 As it pertains to safety valves, what is the definition of blow down? #253 Referring to the illustrated huddling-chamber safety valve, what statement concerning the blow down adjusting ring