What Is An Electromagnetic Valve?

Electromagnetic valve is an automatic basic element used to control fluid and is an actuator. In the industrial control system, it is mainly used to adjust the direction, flow rate, speed and other parameters of the medium. In addition, the electromagnetic is a kind of tractor parts, which has been widely used in various agricultural machine.

 

 

Working Principle of Electromagnetic Valve

There is a closed cavity in the electromagnetic valve, there are holes in different positions of the cavity, each hole is connected with different tubes. There is a piston in the middle of the cavity and two electromagnets on both sides of the cavity. The electromagnet is used to control the movement of the valve body to open or close different holes, so that the hydraulic oil can enter different drain pipes, and then push the piston of the cylinder through the pressure of the oil, and the piston rod drives the piston rod, which drives the mechanical device.

 

 

Classification and Characteristics of Electromagnetic Valve

1. Direct acting electromagnetic valve: When the electromagnetic valve is energized, the magnetic coil generates electromagnetic force to lift the closure member from the valve seat, so as to open the valve. When the valve is out of power, the electromagnetic force disappears, and the spring presses the closure member on the valve seat, thus closing the valve. This kind of valve can work normally in vacuum, negative pressure and zero pressure environment, but its diameter is generally less than 25 mm.

 

2. Step type direct acting electromagnetic valve: When there is no pressure difference between the inlet and outlet of the valve, after the valve is powered on, the electromagnetic force directly lifts the closure member of the guiding valve and the main valve upward in order to open the valve. When the pressure difference between the inlet and the outlet reaches the starting pressure difference, after the valve is powered on, the pressure in the lower chamber of the main valve rises and the pressure in the upper chamber drops, so the main valve is pushed upward by the pressure difference. After the valve is out of power, the guiding valve uses spring force or pressure to push the closing part down to make the valve close. This valve can also work in zero pressure difference, vacuum, high pressure environment, but at this time the required power is large, and the valve must be installed horizontally.

 

3. Pilot operated electromagnetic valve: After the valve is powered on, the electromagnetic force will open the pilot hole, so that the pressure in the upper chamber will drop rapidly. The pressure difference formed around the closure member will push the closure member upward to move, so as to open the valve. When the valve is out of power, the spring force closes the pilot hole, forming a low pressure difference around the closure member, and the pressure pushes the closure member to move downward, thus closing the valve. The upper limit of the fluid pressure range of this kind of valve is high, which can be installed arbitrarily, but the condition of the fluid pressure difference must be met.