Solenoid valve is an industrial equipment controlled by electromagnetic. It is an automation basic component used to control fluid. It belongs to actuator and is not limited to hydraulic and pneumatic. Used in industrial control systems to adjust the direction, flow, speed and other parameters of the medium. The solenoid valve can cooperate with different circuits to achieve the desired control, and the accuracy and flexibility of the control can be guaranteed. There are many kinds of solenoid valves. Different solenoid valves play a role in different positions of the control system. The most commonly used ones are check valves, safety valves, directional control valves, speed control valves, etc.

 

 

working principle

There is a closed cavity in the solenoid valve with through holes at different positions. Each hole is connected to a different oil pipe. In the middle of the cavity is a piston. There are two electromagnets on both sides. Which side of the magnet coil will be attracted to the valve body when it is energized. On the other hand, by controlling the movement of the valve body to open or close the different oil discharge holes, and the oil inlet is normally open, the hydraulic oil will enter the different oil discharge pipes, and then the piston of the cylinder is pushed by the oil pressure. Drive the piston rod, and the piston rod drives the mechanical device. In this way, the mechanical movement is controlled by controlling the current on and off of the electromagnet.

Step-by-step direct-acting solenoid valve

Principle: It is a principle that combines direct action and pilot type. When there is no pressure difference between the inlet and the outlet, the electromagnetic force directly lifts the pilot small 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 power 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 pressure difference pushes the main valve upward; when the power is off, the pilot valve uses a spring The force or medium pressure pushes the closing piece and moves downward to close the valve.

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

Pilot solenoid valve

Principle: When energized, electromagnetic force opens the pilot hole, the pressure in the upper chamber drops rapidly, and a high pressure difference is formed around the closing member. The fluid pressure pushes the closing member to move upward and the valve opens; when the power is off, the spring force controls the pilot The hole is closed, and the inlet pressure passes through the bypass hole to quickly form a lower and upper pressure difference around the valve closing member. The fluid pressure pushes the closing member to move downward and close the valve.

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

2. The solenoid valve is 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, cryogenic solenoid valves, gas solenoid valves, fire solenoid valves, ammonia solenoid valves, gas solenoid valves, liquid solenoid valves, miniature 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.

Common malfunctions

The solenoid valve is composed of a solenoid coil and a magnetic core, and is a valve body containing one or more holes. When the coil is energized or de-energized, the operation of the magnetic core will cause the fluid to pass through the valve body or be cut off to achieve the purpose of changing the direction of the fluid. The electromagnetic part of the solenoid valve is composed of fixed iron core, moving iron core, coil and other parts; the valve body part is composed of spool valve core, spool valve sleeve, spring base and so on. The solenoid coil is directly installed on the valve body, and the valve body is enclosed in a sealed tube, forming a simple and compact combination. The solenoid valves commonly used in our production include two-position three-way, two-position four-way, two-position five-way, etc. Let me first talk about the meaning of the two positions: for the solenoid valve, it is electrified and de-energized, and for the controlled valve, it is open and closed.