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 |
A) The valve would fail in the fully closed position, most likely resulting in a low fuel oil temperature alarm condition. |
B) The valve would fail in the exact position just before the loss of pilot air. The fuel temperature will fluctuate with changes in fuel demand. |
C) The valve would fail in the fully open position, most likely resulting in a high fuel oil temperature alarm condition. |
D) It is not possible to predict how the valve would respond to a loss of pilot air. |