In principle, solenoid valves are divided into three categories:

　　Direct Acting Solenoid Valve

　　Principle: When the solenoid coil is energized, electromagnetic force is generated 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.

　　Features: It can work normally under vacuum, negative pressure, and zero pressure, but the diameter generally does not exceed 25mm.

　　Stepping Direct Acting Solenoid Valve

　　Principle: Combination of direct-acting and pilot-acting. When there is no pressure difference between the inlet and outlet, the electromagnetic force directly lifts the pilot small valve and the closed part of the main valve in turn, and the valve opens. When the inlet and outlet reach the starting pressure difference, after energizing, the electromagnetic force pilots the small valve, the pressure in the lower chamber of the main valve rises, and the pressure in the upper chamber drops, thereby using the pressure difference to push the main valve upward; when the power is off, the pilot valve uses a spring Force or medium pressure pushes the closing member to move down to close the valve.

　　Features: It can work under zero pressure difference or vacuum high pressure, but with high power, it must be installed horizontally.

　　Pilot solenoid valve

　　Principle: When energized, the pilot hole is opened by electromagnetic force, and the pressure in the upper cavity drops rapidly, forming a high and low-pressure difference around the closing part. The fluid pressure pushes the closing part upwards, and the valve opens; when the power is cut off, the spring force closes the pilot valve port, and the inlet pressure rapidly forms a low, high, and high-pressure difference around the valve closing part through the bypass hole, and the fluid pressure pushes the closing part downwards. Close the valve.

　　Features: The upper limit of the fluid pressure range is high, and it can be installed arbitrarily (customization required) but must meet the fluid pressure difference condition.

　　Solenoid valves are divided into six categories in terms of valve structure, materials, and principles: direct-acting diaphragm structure, step-type direct-acting diaphragm structure, pilot-type diaphragm structure, direct-acting piston structure, step-type direct-acting piston structure, and Pilot piston structure.

　　Solenoid valves are classified by function: water solenoid valve, Steam Solenoid Valve, refrigeration solenoid valve, cryogenic solenoid valve, gas solenoid valve, fire solenoid valve, ammonia solenoid valve, gas solenoid valve, liquid solenoid valve, micro solenoid valve, 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.

　　Water Rotameter is also our product, welcome to consult and purchase.