Solenoid air pilot operated valves can be classified into two types: Spring Return (Monostable) and Spring Return (Bistable).
Spring Return (Monostable) solenoid air pilot operated valves have a single stable position and are held in place by a solenoid. When the solenoid is de-energized, a spring returns the valve to its default position. This type of valve is often used in applications where the valve needs to return to a specific position in the event of power failure.
Spring Return (Bistable) solenoid air pilot operated valves, on the other hand, have two stable positions and do not require a solenoid to hold the valve in place. When the solenoid is energized, it shifts the valve from one stable position to the other. When the solenoid is de-energized, the valve remains in its new position, until the solenoid is energized again. This type of valve is often used in applications where a specific valve position needs to be maintained even in the absence of power.
In summary, the main difference between Spring Return (Monostable) and Spring Return (Bistable) solenoid air pilot operated valves is the number of stable positions they have and the way in which they maintain their position in the absence of power.
