Know ---- solenoid valve

 

This entry by the "popular science" Encyclopedia of science entry preparation and application of the project review.

Electromagnetic valve (electromagnetic valve) is the use of electromagnetic control of industrial equipment, is used to control fluid automation basic components, is the actuator, not limited to hydraulic, pneumatic. Used in industrial control system to adjust the media direction, flow, speed and other parameters. Solenoid valve can cooperate with different circuits to achieve the desired control, and control accuracy and flexibility can be guaranteed. Solenoid valve there are many, different solenoid valve in the control system to play a role in different locations, the most commonly used is the one-way valve, safety valve, directional control valve, speed control valve.

 

Solenoid valve under the industrial control, the main industrial features Safe, convenient, model number, use Widely used types of check valves, safety valves, direction control valves and other selection principles Applicability, reliability, safety, economy

 

working principle

Solenoid valve has a closed cavity, opened in different locations through-hole, each hole connected to different tubing, the middle of the cavity is a piston, on both sides of the two electromagnets, which side of the magnet coil body will be attracted to the valve Edge, by controlling the movement of the valve body to open or close different drain hole, and the inlet hole is normally open, the hydraulic oil will enter the different drain pipe, and then through the oil pressure to promote the cylinder piston, piston and Driven piston rod, piston rod drive mechanism. This controls the mechanical movement by controlling the current flow through the electromagnet.

 

The main classification

 

1, the solenoid valve from the principle is divided into three categories:

 

Direct-acting solenoid valve

Principle: When power is on, the electromagnetic coil generates electromagnetic force to lift the closing piece from the valve seat and the valve opens. When the electric power is off, the electromagnetic force disappears. The spring presses the closing piece on the valve seat and the valve closes.

Features: In vacuum, negative pressure, zero pressure can work normally, but the path generally does not exceed 25mm.

 

Step by step direct-acting solenoid valve

Principle: It is a combination of direct acting and pilot principle. When there is no pressure difference between inlet and outlet, the electromagnetic force directly lifts the pilot valve and main valve closing element upwards and the valve opens. When the inlet and outlet to achieve the start of the pressure difference, the electricity, the solenoid pilot small valve, the main valve lower chamber pressure rises, the pressure on the chamber down, so that the use of pressure to push the main valve open; power, the pilot valve spring Force or media pressure to push the closure, move down, the valve closed.

Features: At zero pressure or vacuum, high pressure can also be * action, but the power is larger, the requirement must be horizontal installation.

 

Pilot solenoid valve

Principle: When power is on, the electromagnetic force opens the pilot hole and the pressure in the upper chamber decreases rapidly. A low pressure drop 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 hole closes and the inlet pressure rapidly passes through the bypass hole to quickly create a low pressure differential across the closing valve. The fluid pressure forces the closing member to move downward and close the valve.

Features: High fluid pressure range high, can be installed (to be customized), but must meet the fluid pressure conditions.

2, the solenoid valve from the valve structure and material on the difference between the principle and the difference is divided into six sub-categories: direct acting diaphragm structure, step-by-step diaphragm structure, the leading diaphragm structure, direct acting piston structure, Step-by-step dynamic piston structure, the pilot piston structure.

3, the solenoid valve in accordance with the functional classification: 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, Pulse solenoid valve, solenoid valve normally open solenoid valve, solenoid valve with oil, DC solenoid valve, high pressure solenoid valve, explosion-proof solenoid valve.