Working principle of solenoid valve

There is a closed cavity in the solenoid valve. There are through holes in different positions. Each hole leads to different oil pipes. There is a valve in the middle of the cavity and two electromagnets on both sides. The valve body will be attracted to which side when the magnet coil is electrified. The movement of the valve body will be controlled to block or leak different oil drain holes. The oil inlet hole is normally open, and the hydraulic oil will enter different oil drain pipes, Then the oil pressure pushes the oil rigid piston, the piston drives the piston rod, and the piston rod drives the mechanical device. In this way, the mechanical movement is controlled by controlling the current of the electromagnet.

Tracing the development history of solenoid valve:

Up to now, the solenoid valves at home and abroad are divided into three categories in principle (direct acting, step-by-step pilot), and six sub categories in principle (direct acting diaphragm structure, step-by-step heavy plate structure, pilot membrane structure, step-by-step direct acting piston structure, step-by-step direct acting piston structure).

Direct acting solenoid valve:

Principle: when electrified, the electromagnetic coil generates electromagnetic force to lift the closing part from the valve seat and open the valve; When the power is cut off, the electromagnetic force disappears, the spring presses the closing part on the valve seat, and the valve closes.

Features: in vacuum, negative pressure, zero pressure can work normally, but the diameter is generally not more than 25 mm.

Distributed direct acting solenoid valve:

Principle: it is a combination of direct acting and pilot type. When there is no pressure difference between the inlet and outlet, the electromagnetic force will lift the small pilot valve and the main valve closing parts up one by one and open the valve. When the pressure difference between the inlet and outlet reaches the starting pressure, the electromagnetic force will pilot the small valve, the pressure in the lower chamber of the main valve will rise, and the pressure in the upper chamber will drop, so as to use the pressure difference to push the main valve upward; When the power is cut off, the pilot valve uses spring force or medium pressure to push the closing part and move downward to close the valve.