Under what circumstances does a control valve need to be equipped with a solenoid valve?
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Under what circumstances does a control valve need to be equipped with a solenoid valve? .
Solenoid valves are used in situations where rapid adjustment of control valves is required. For example, when a certain process variable exceeds its limit, it is necessary to cut off the air supply to the valve actuator, so as to cause a rapid loss of air pressure and bring the valve back to a safe state. If there is no solenoid valve, the positioner must be used to adjust the valve slowly, making it impossible to achieve rapid valve operation. Therefore, the target for supplying air is the valve positioner; the solenoid valve merely acts as a switch for supplying air to the positioner. Basically, control valves are standardly equipped with positioners and pressure reducers, while on-off valves come standard with solenoid valves and pressure reducers. Limit switches are mostly used for on-off valves and are available as an optional accessory.
Thank you, OP; I agree with your view