Excavator accessories 323-7898 rotary priority pilot valve

Working principle of solenoid valve

     Tracing the history of solenoid valve, so far, the solenoid valve at home and abroad is divided into three categories in principle (namely: direct-acting, step-by-step direct-acting, pilot-operated), According to the difference of valve disc structure, material and principle, it is divided into six sub-categories (direct acting diaphragm structure, step diaphragm structure, pilot diaphragm structure, direct acting piston structure, step piston structure, pilot piston structure).

(1) Direct acting solenoid valve
Principle: When energized, the electromagnetic force generated by the electromagnetic coil lifts the closing part from the seat, and the valve opens; When the power is off, the electromagnetic force disappears, the spring force presses the closing part on the seat, and the valve is closed.
Features: It can work normally under vacuum, negative pressure and zero pressure, but generally the diameter does not exceed 25mm.

(2) step by step direct acting solenoid valve
Principle: It is a combination of direct action and pilot principle, when the inlet and outlet pressure difference ≤0.05Mpa, power, the electromagnetic force directly to the pilot small valve and the main valve closing parts lift up in turn, the valve opens. When the inlet and outlet pressure difference > 0.05Mpa, when the power is on, the electromagnetic force first opens the pilot small valve, the pressure in the lower chamber of the main valve rises, and the pressure in the upper chamber drops, so that the pressure difference is used to push the main valve upward; When the power is off, the pilot valve and the main valve use spring force or medium pressure to push the closing part and move down to close the valve.
Features: At zero pressure difference or vacuum, high pressure can also work reliably, but the power is large, requiring vertical installation