Question 265General Subjects - Assistant Engineer70% to pass
Referring to the illustrated pneumatically operated diaphragm actuated control valve, what statement is true? Illustration GS-0051
AI Explanation
The correct answer is A) The control valve is direct-acting and normally open (NO).
In a direct-acting pneumatic diaphragm control valve, the valve opens when the pneumatic signal increases, allowing flow through the valve. This is the normal operating condition, so the valve is normally open (NO). The other options are incorrect because an indirect-acting valve would close when the pneumatic signal increases, and a normally closed (NC) valve would be closed in its normal state without an actuating signal.
Related Questions
#263 Assuming that the flow is from left to right on the illustrated pneumatically operated diaphragm actuated control valve, what statement is true? Illustration GS-0051 #264 In the illustrated pneumatically operated, diaphragm actuated control valve, what statement is true concerning the opening and closing forces acting upon the control diaphragm? Illustration GS-0051 #266 Suppose the illustrated pneumatically operated diaphragm actuated control valve is used to control the fuel oil outlet temperature of a steam-heated heavy fuel oil heater by controlling the steam flow. What would be the result if there was a complete loss of pilot air being delivered to the valve actuator? Illustration GS-0051 #267 Suppose the pilot pressure is from 3 to 15 psig for the illustrated pneumatically operated, diaphragm actuated control valve. Assuming the control valve is trimmed for a linear response and the travel position indicator is calibrated in percentage, what would be the approximate pilot pressure if the position indicator showed the valve to be 75% open? Illustration GS-0051 #268 What statement representing the primary purpose of a steam trap is true?