Direct acting solenoid valve
Principle: 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, the spring presses the closing member on the valve seat, and the valve closes.
Features: It can work normally in vacuum, negative pressure and zero pressure, but the diameter generally does not exceed 25mm.
Step-by-step direct acting solenoid valve
Principle: 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 closing member of the main valve 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.
Pilot solenoid valve
Principle: When energized, the electromagnetic force opens the pilot hole, and the pressure in the upper chamber drops rapidly, forming a pressure difference 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 opens the pilot hole. The hole is closed, and the inlet pressure quickly passes through the bypass hole to form a pressure difference around the valve closing member, and the fluid pressure pushes the closing member to move down and close the valve.
Features: The upper limit of the fluid pressure range is relatively high, and it can be installed arbitrarily (customization is required) but must meet the fluid pressure differential condition.
2. Solenoid valves are divided into six sub-categories from the difference in valve structure and material and principle: direct-acting diaphragm structure, step-by-step direct-acting diaphragm structure, pilot diaphragm structure, direct-acting piston structure, Step-by-step direct-acting piston structure, pilot piston structure.
3. Solenoid valves are classified according to their functions: water solenoid valves, steam solenoid valves, refrigeration solenoid valves, low temperature solenoid valves, gas solenoid valves, fire solenoid valves, ammonia solenoid valves, gas solenoid valves, liquid solenoid valves, micro solenoid valves, Pulse solenoid valve, hydraulic solenoid valve normally open solenoid valve, oil solenoid valve, DC solenoid valve, high pressure solenoid valve, explosion-proof solenoid valve, etc.