What Is A Solenoid Valve?

What is a solenoid valve?

Solenoid valve is an industrial equipment controlled by electromagnetic. It is an automatic basic component used to control fluid. It belongs to actuator and is not limited to hydraulic and pneumatic. It is used to adjust the direction, flow, speed and other parameters of the medium in the electronic control system. Solenoid valves can cooperate with different circuits to achieve the expected control, and the control accuracy and flexibility can be guaranteed.

Working principle of a solenoid valve

There is a closed cavity in the solenoid valve, and there are through holes in different positions. Each hole is connected to a different oil pipe. There is a piston in the middle of the cavity, and two electromagnets on both sides. On the other hand, different oil discharge holes are opened or closed by controlling the movement of the valve body, while the oil inlet hole is normally open, the hydraulic oil will enter different oil discharge pipes, and then the piston of the cylinder is pushed by the pressure of the oil, and the piston again Drive the piston rod, and the piston rod drives the mechanical device. In this way, the mechanical movement is controlled by controlling the electric current on and off of the electromagnet.

Types of solenoid valves

There are three main solenoid valve types. Different solenoid valves play a role in different positions of the control system.

Direct-acting solenoid valves

When the direct-acting solenoid valve is energized, the electromagnetic coil generates electromagnetic force to lift the closing member from the valve seat, and the valve opens; when the power is turned off, the electromagnetic force disappears, and the spring presses the closing member on the valve seat, and the valve closes. It can work normally in vacuum, negative pressure and zero pressure, but the diameter generally does not exceed 25mm.

Pilot solenoid valves

When the pilot solenoid valve is energized, the electromagnetic force opens the pilot hole, the pressure in the upper chamber drops rapidly, and a pressure difference is formed around the closing part, and the fluid pressure pushes the closing part to move upward, and the valve opens; when the power is off, the spring force the pilot hole closed, the inlet pressure passes through the bypass hole and the chamber quickly forms a pressure difference around the valve closing member. The fluid pressure pushes the closing member down to close the valve. The upper limit of the fluid pressure range is relatively high, and it can be installed arbitrarily (customization is required), but the fluid pressure difference condition must be met.

Step-by-step direct-acting solenoid valves

This type is a combination of direct-acting and pilot-operated. It can also operate safely under zero pressure difference or vacuum and high pressure, but the power is relatively large, and it must be installed horizontally.