Working principle of pilot solenoid valve
The pilot solenoid valve is generally used for large diameter and high pressure. When the valve of this structure is opened, the minimum pressure of the solenoid valve must not be lower than 0.05 MPa, and there must be pilot pressure, otherwise it cannot be opened. In addition, the pilot solenoid valve has a larger flow capacity than the direct-acting solenoid valve, and generally has a CV of up to three or more. For the purity of compressed air is higher, the direct motion is not so strict.
Principle: When energized, the electromagnetic force opens the pilot hole, the pressure in the upper chamber drops rapidly, and a pressure difference between the lower part and the lower part is formed around the closing member. The fluid pressure pushes the closing member upward to move the valve to open; when the power is off, the spring force leads the pilot. The hole is closed, and the inlet pressure passes through the bypass hole. The rapid chamber forms a lower low and high pressure difference around the valve member, and the fluid pressure pushes the closing member downward to close the valve.