The air flows to actuator when solenoid valve is energized, and the air is vented from actuator when solenoid valve is deenergized(reverse case available).
How Solenoid Valve Works?
1-way or 4-way valve is applied in case of emergency isolation of control valve, however 2-way valve is applied to block the air signal by electric signal, and 3-way valve is applied to emergency isolation or emergency opening of diaphragm actuator or single acting actuator. 4-way valve is applied to dual acting actuator.
The valve has a double acting piston actuator and I want the valve to be fail last. But as per the above configuration I don’t think we can achieve fail last position. can you help me with the same?
I think when the IA pressure goes down the lock up valve will shut trapping the pressure at it’s outlet! This will keep the air operated solenoids always open allowing the air from the actuator to escape.
Do you think the above configuration is correct to achieve fail last position in case of IA failure?
