Principle of Solenoid Directional Valve

Mar 24, 2020

The electromagnetic directional valve uses an electromagnet to push the valve core to control the flow direction. The use of electromagnetic reversing valve can make the operation light and easy to realize automatic operation, so it is widely used.

The electromagnetic directional valve only uses an electromagnet to control the movement of the spool. The structure and type of the spool can be various. There are many types such as three-way, four-way and three-way five-way. Generally, one solenoid is used for two-position valve, and two solenoids are used for three-position valve.

There are two types of electromagnets for controlling solenoid valves: AC and DC. The voltage of AC electromagnets is generally 220 volts. Its characteristics are large starting force, short commutation time and low price. However, when the valve core is stuck or the suction force is insufficient to make the iron core unable to attract, the electromagnet is easy to burn out due to excessive current, so the working reliability is poor, there is impact during operation, and the life is low. The DC electromagnet voltage is generally 24 volts. It has the advantages of reliable operation, no burnout due to stuck valve core, long life and small size, but the starting force is smaller than that of AC electromagnets, and rectifier equipment is required when there is no DC power supply. In order to improve the working reliability and life of electromagnetic directional valves, in recent years, wet electromagnets are increasingly widely used at home and abroad. There is no need to seal between this electromagnet and the slide valve push rod, eliminating the friction at the O-ring seal. The outside of its electromagnetic coil is directly sealed with engineering plastics, and it is not used as a metal shell. This not only ensures insulation but also facilitates heat dissipation, so it has reliable work, low impact and long life.

Directional valve

Role: Change the relative working position of the valve core in the valve body, so that the oil ports of the valve body are connected or disconnected, so as to control the reversing or start-stop of the actuator.

1 Classification of directional valves

Seat valve directional valve

Divided by structure <slide valve directional valve

Rotary valve directional valve

2 Spool valve directional valve

(1) Structure and working principle of directional valve

Body: Cylindrical hole with multi-level undercut

Structure <

Spool: Cylinder with multiple circular grooves

Category:

Two

According to the number of working positions <three digits: the number of working positions of the valve core relative to the valve body.