Main Classification of Solenoid Valves

1. Solenoid valves can be divided into three categories in principle:

Direct-acting solenoid valve

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

Characteristic: It can work normally in vacuum, negative pressure and zero pressure, but its diameter generally does not exceed 25 mm.

Step-by-step direct-acting solenoid valve

Principle: It is a combination of direct and pilot principle. When there is no pressure difference between the inlet and the outlet, the electromagnetic force directly lifts the pilot valve and the main valve closing parts upward, and the valve opens. When the inlet and outlet reach the start-up pressure difference, after electrification, the electromagnetic force leads the small valve, the lower chamber pressure of the main valve rises, and the upper chamber pressure decreases, so that the main valve is pushed upward by the pressure difference; when power is cut off, the pilot valve uses spring force or medium pressure to push the closing parts downward, so that the valve closes.

Characteristic: It can also operate at zero pressure difference or vacuum or high voltage, but the power is large, which requires horizontal installation.

Pilot solenoid valve

Principle: When electrified, the electromagnetic force opens the pilot hole, and the pressure of the upper chamber drops rapidly, forming a high differential pressure around the closure. The fluid pressure pushes the closure upward and the valve opens. When the power is cut off, the spring force closes the pilot hole, and the inlet pressure quickly forms a low differential pressure around the closure through the bypass hole, and the fluid pressure pushes the closure downward. Move and close the valve.

Features: The upper limit of fluid pressure range is high. It can be installed arbitrarily (customized), but it meets the condition of fluid pressure difference.

2. Solenoid valves are divided into six sub-categories: direct diaphragm structure, step-by-step direct diaphragm structure, pilot diaphragm structure, direct piston structure, step-by-step direct piston structure and pilot piston structure.

3. Solenoid valves are classified according to their functions: water solenoid valve, steam solenoid valve, refrigeration solenoid valve, low temperature solenoid valve, gas solenoid valve, fire-fighting solenoid valve, ammonia solenoid valve, gas solenoid valve, liquid solenoid valve, micro solenoid valve, pulse solenoid valve, hydraulic solenoid valve, oil solenoid valve, direct current solenoid valve, high-pressure solenoid valve, explosion-proof solenoid valve, etc.