A question about control valves
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Control valve FOL: valve opening at 50; it remains at 50 when air supply is stopped. What is the state during a power outage when there is no wind, and what is the state during a power outage when wind is present?
Flo — the position of the control valve remains unchanged in the event of a supply air interruption (position holding); the valve opens when power is lost (when the control signal becomes low).
FOL, O, and L all refer to the condition when there is a loss of wind, and have nothing to do with electric current. First, lock position L; once the locking valve starts to leak, it gradually opens. Wind is the fundamental source of energy for valve operation, while electric current is used to transmit signals.
Flo — the position of the control valve remains unchanged in the event of a supply air interruption (position holding); the valve opens when power is lost (when the control signal becomes low).
Pneumatic control valves are driven by compressed air. The faulty state of such valves refers to the condition when there is no air pressure signal. Whether it is the air supply that causes the loss of this signal, or a current signal, or the fact that the solenoid valve loses power (or gains power), it makes no difference; in any case, the loss of the air pressure signal is what causes the control valve to fail and end up in an open, closed, unlocked, or locked position.
They are all in the on state; turn it on in case of a fault