(1) 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 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.

(2) Step-by-step direct-acting solenoid valve:

Principle: It is a combination of direct action and pilot type. When there is no pressure difference between the inlet and the outlet, after the power is turned on, the electromagnetic force directly lifts the pilot valve and the main valve closing member upwards in turn, 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 chamber of the main valve rises, and the pressure in the upper chamber drops, so that the main valve is pushed up by the pressure difference; when the power is off, the pilot valve uses a spring The force or medium pressure pushes the closing member, moving downward, causing the valve to close.

Features: It can also act safely under zero pressure difference or vacuum and high pressure, but the power is large and must be installed horizontally.

(3) Pilot solenoid valve:

Principle: When the power is turned on, the electromagnetic force opens the pilot hole, the pressure in the upper chamber drops rapidly, and a pressure difference between upper and lower sides is formed around the closing member, and the fluid pressure pushes the closing member to move upward, and the valve opens; When the hole is closed, the inlet pressure passes through the bypass hole to quickly form a pressure difference between the lower and upper parts around the valve closing member, and the fluid pressure pushes the closing member to move down to close the valve.

Features: The upper limit of the fluid pressure range is high, which can be installed arbitrarily (need to be customized) but must meet the fluid pressure differential conditions.

2. The solenoid valve is divided into six sub-categories from the difference in valve structure and material and the difference in 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 and pilot piston structure.

3. Solenoid valves are classified by function: water solenoid valve, steam solenoid valve, refrigeration solenoid valve, low temperature 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.

2. According to the material, it can be divided into three categories

1) Stainless steel solenoid valve: It is the most common solenoid valve product. Stainless steel is the most popular among users because of its good quality and stable operation. The electromagnetic valve

*This series of products are widely used in textile, printing, chemical, plastic, rubber, pharmaceutical, food, building materials, machinery, electrical appliances, surface treatment and other production and scientific research departments, as well as bathrooms, canteens, air conditioners and other people's daily life facilities

2) Brass solenoid valve: Some users with low requirements will choose brass solenoid valve products. The price of such solenoid valve products is relatively low and suitable for ordinary working environments.

* This series of products are generally suitable for liquid, water, gas, hot water, oil, gas and other media.

3) Plastic solenoid valve: In some special workplaces, and solenoid valves used in special media, such as working environments with acid and alkaline media, solenoid valve products made of brass and stainless steel are easily corroded, so special materials are used. (Engineering plastics PVC, CPVC, UPVC, ABS or PTFE, etc.) plastic solenoid valves are particularly excellent in corrosion resistance.

* This series of products are suitable for drinking water, all kinds of untreated sewage, rainwater, seawater and various acid-base salt solutions, organic solvents, etc.

2. Solenoid valves can be divided into on-off solenoid valves and proportional solenoid valves according to their functions

1) The on-off solenoid valve acts as a switch. When there is current flowing, the solenoid valve controls the circuit or the oil circuit to be on and off.

2) Proportional solenoid valve, that is, according to the input current, the output pressure is different. When the input current is changed, the output pressure of the solenoid valve can be changed, which is mostly used in hydraulic systems.

Source of this article: 360 Encyclopedia