Working principle and function of solenoid valve
Solenoid valve is a kind of industrial equipment controlled by electromagnetism, which is particularly common in industrial machine control and industrial valve. It can control the direction, flow, speed and other parameters of the medium, so as to control the valve switch.
1、Direct acting solenoid valve
Principle: When the normally closed type is energized, the solenoid coil generates electromagnetic force to lift the open part from the valve seat, and the valve opens; When the power is cut off, the electromagnetic force disappears, the spring presses the open part on the valve seat, and the valve opens.
Features: It can work normally under vacuum, negative pressure and zero pressure, and the diameter generally does not exceed 25mm.
2、Step-by-step direct-acting solenoid valve
Principle: when the inlet and outlet reach the starting pressure difference, the electromagnetic force pilot small valve, the lower chamber pressure of the main valve rises, the upper chamber pressure drops, and the main valve is pushed upward by the pressure difference; 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.
Features: It can also operate at zero differential pressure, vacuum and high pressure, but the power is large and must be installed horizontally.
3、Indirect pilot solenoid valve
Principle: when energized, the electromagnetic force opens the pilot hole, and the pressure in the upper chamber drops rapidly, forming a high and low pressure difference around the open part. The fluid pressure pushes the open part upward, and the valve opens; When the power is cut off, the spring force opens the pilot hole, and the inlet pressure rapidly forms a pressure difference of lower and higher around the valve closing parts through the bypass hole. The fluid pressure pushes the open parts downward to open the valve.
Features: small volume, low power, high upper limit of fluid pressure range, can be installed at will, but must meet the conditions of fluid pressure difference.
