The working principle of solenoid valve

Author:     Published time:2016-10-10 16:16     Reading times:850    

Solenoid valve is used to control the basic automation of fluid components, are actuators; not limited to hydraulic, pneumatic. Solenoid valves are used to control the direction of hydraulic flow. The mechanical devices in the plant are normally controlled by hydraulic steel, so solenoid valves are used.

    The working principle of the solenoid valve, solenoid valve in a closed cavity, in different positions open through the hole, each hole leads to a different tubing, the middle of the valve chamber, two are two electromagnets, which side of the magnet coil The valve body will be attracted to which side, by controlling the movement of the valve body to stall or leak out the different oil discharge hole, and the oil hole is always open, the hydraulic oil will enter a different drain pipe, and then through Oil pressure to promote the piston cylinder, piston and drive the piston rod, piston rod driven mechanical device. This control of the electromagnet current to control the mechanical movement.

So far, the solenoid valve at home and abroad from the principle is divided into three categories (ie: direct-acting, step-by-step direct, pilot-type), and from the valve structure and materials (Direct-acting diaphragm structure, step-by-step re-plate structure, pilot membrane structure, direct-acting piston structure, step-by-step direct piston structure, pilot piston structure) are differentiated from the principle.

Direct-acting solenoid valve:

     Principle: When energized, the electromagnetic coil generates electromagnetic force to lift the closure from the seat, the valve opens; power, the electromagnetic force disappears, the spring to close the pieces in the valve seat, the valve closed.

    Features: in vacuum, negative pressure, zero pressure when the normal work, but generally not more than 25mm diameter.

    Distribution Direct-acting solenoid valve:

     Principle: It is a direct-acting and pilot-type combination of principles, when there is no pressure difference between the inlet and outlet, power, the electromagnetic force directly to the pilot valve and the main valve closing parts in order to lift up the valve open. When the inlet and outlet pressure to start, the electromagnetism after the pilot small valve, the main valve under the chamber pressure increases, the upper chamber pressure drop, thus using the pressure to push up the main valve; power, the pilot valve using spring The force or medium pressure pushes the closure piece downward to move the valve closed.

    Features: In the zero-pressure or vacuum, high pressure can also be action, but the power is greater, the requirements must be installed horizontally.

     Pilot solenoid valve:

    Principle: When energized, the electromagnetic force to open the pilot hole, the pressure on the rapid decline in the chamber around the formation of a high pressure on the lower part of the pressure, the fluid pressure to promote the closure of moving up, the valve open; power, the spring force to the pilot The orifice closes and the inlet pressure passes through the bypass hole. The rapid chamber forms a low differential pressure around the valve member. The fluid pressure urges the closure member down to close the valve.

     Features: Fluid pressure range of the upper limit, can be any installation (to be customized), but must meet the fluid pressure conditions.