Solenoid valve is an industrial equipment controlled by electromagnetism. It is an automatic basic component used to control fluid and belongs to actuator.
Pneumatic solenoid valve is one of them. It blocks or leaks different oil discharge holes 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 pass through the pneumatic solenoid valve. The pressure of the oil in the valve pushes the piston of the oil cylinder, so that the mechanical movement of the entire solenoid valve is controlled by controlling the current of the electromagnet of the pneumatic solenoid valve.
There is a closed cavity in the pneumatic solenoid valve, and there are through holes in different positions. Each hole of the pneumatic solenoid valve leads to a different air pipe. There is a valve in the middle of the cavity, and two electromagnets on both sides. Which side of the magnet coil is powered The valve body will be attracted to whichever side. When we talk about the working position of the pneumatic solenoid valve (the solenoid valve is open or closed), it actually refers to the position of the spool of the pneumatic solenoid valve. When the spool of the pneumatic solenoid valve is in different positions, it plays a role of turning on or closing each interface on the valve body. The electrical conversion component converts the electrical signal into a pneumatic signal, and then the electrical signal input controls the pneumatic output. The solenoid valve performs this release, change or stop of the air flow on command.
Classification of pneumatic solenoid valves
(1) Direct acting solenoid valve
When 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. The characteristic is that it can work normally under vacuum, negative pressure and zero pressure, but the diameter generally does not exceed 25mm.
(2) Distributed direct-acting solenoid valve
It is a combination of direct-acting and pilot-operated principles. When there is no pressure difference between the inlet and outlet, after power is applied, the electromagnetic force directly lifts up the pilot small valve and the main valve closing member in sequence, and the valve opens. When the inlet and outlet reach the starting pressure difference, after the power is turned on, the electromagnetic force pilots the small valve, the pressure in the lower cavity of the main valve rises, and the pressure in the upper cavity drops, so that the main valve is pushed upward by the pressure difference; when the power is off, the pilot valve uses a spring Force or medium pressure pushes the closing member, which moves down and closes the valve.
(3) Pilot solenoid valve
When the power is turned on, the electromagnetic force opens the pilot hole, the pressure in the upper chamber drops rapidly, and a pressure difference is formed around the closing member, and the fluid pressure pushes the closing member to move upward, and the valve opens; when the power is turned off, the spring force closes the pilot hole , the inlet pressure passes through the bypass hole and quickly forms a pressure difference around the valve closing part, and the fluid pressure pushes the closing part down to close the valve.
The role of pneumatic solenoid valve
There are two main functions of the pneumatic solenoid valve: one is to silence the noise, otherwise the sound is too loud when the solenoid valve is exhausted, especially when there are many solenoid valves; the other is to prevent dust and other fine particles in the environment Particles enter the solenoid valve, which may cause the movement of the solenoid valve spool to be blocked, thereby reducing the service life of the solenoid valve.