Two way solenoid valve

The solenoid valve has a sealed chamber with through holes at different positions, each connected to a different oil pipe. The middle of the chamber is a piston, and there are two electromagnets on both sides. The magnetic coil on which side is energized will attract the valve body to which side. By controlling the movement of the valve body, different oil discharge holes can be opened or closed. The oil inlet hole is usually open, and hydraulic oil will enter different oil discharge pipes, and then push the piston of the oil cylinder through the pressure of the oil, The piston drives the piston rod, which drives the mechanical device. In this way, mechanical motion is controlled by controlling the current flow of the electromagnet.

(1) Direct acting solenoid valve:

Principle: When energized, the electromagnetic coil generates electromagnetic force to lift the closing part from the valve seat, and the valve opens; When the power is cut off, the electromagnetic force disappears, and the spring presses the closing part against the valve seat, causing the valve to close.

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


(2) Step by step solenoid valve:

Principle: It is a combination of direct action and pilot type principle. When there is no pressure difference between the inlet and outlet, the electromagnetic force directly lifts the pilot small valve and the main valve closure part upwards after being energized, and the valve opens. When the starting pressure difference between the inlet and outlet is reached, after being energized, the electromagnetic force leads the small valve, causing the pressure in the lower chamber of the main valve to increase and the pressure in the upper chamber to decrease, thereby using the pressure difference to push the main valve upwards; When the power is cut off, the pilot valve uses spring force or medium pressure to push the closing element downwards, causing the valve to close.

Features: It can also operate at zero pressure difference, vacuum, and high pressure, but with high power, it is required to be installed horizontally.


(3) Pilot operated solenoid valve:

Principle: When energized, electromagnetic force opens the pilot hole, causing a rapid decrease in pressure in the upper chamber, creating a high and low pressure difference around the closing element. Fluid pressure pushes the closing element upwards, causing the valve to open; When the power is cut off, the spring force closes the pilot hole, and the inlet pressure quickly forms a pressure difference of low to high around the closing valve through the bypass hole. The fluid pressure pushes the closing valve downward to close the valve.

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

2. Electromagnetic valves are divided into six sub categories based on differences in valve structure, 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, and pilot piston structure.

3. Electromagnetic 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 valves, hydraulic solenoid valves, normally open solenoid valves, oil solenoid valves, DC solenoid valves, high-pressure solenoid valves, explosion-proof solenoid valves, etc.

Security:

1. Corrosive media: It is recommended to use plastic king solenoid valves and all stainless steel; For strongly corrosive media, isolation diaphragm type must be selected. Neutral medium, it is also advisable to use copper alloy as the valve housing material for electromagnetic valves. Otherwise, rust debris often falls off in the valve housing, especially in situations where the action is not frequent. Ammonia valves cannot be made of copper.

2. Explosive environment: Corresponding explosion-proof grade products must be selected, and waterproof and dustproof varieties should be selected for outdoor installation or dusty environments.

3. The nominal pressure of the solenoid valve should exceed the maximum working pressure inside the pipe.


Applicability:

1. Medium characteristics

1) Choose different types of electromagnetic valves for gas, liquid or mixed states;

2) The medium temperature of products with different specifications will burn out the coil, aging the sealing element, and seriously affecting the service life;

3) The viscosity of the medium is usually below 50cSt. If this value is exceeded and the diameter is greater than 15mm, use a multifunctional solenoid valve; When the diameter is less than 15mm, use a high viscosity solenoid valve.

4) When the cleanliness of the medium is not high, a backwash filter valve should be installed in front of the solenoid valve. When the pressure is low, a direct acting diaphragm type solenoid valve can be selected;

5) If the medium flows in a directional manner and does not allow backflow, bidirectional flow is required;

6) The medium temperature should be selected within the allowable range of the solenoid valve.