Directional valve working principle


The function of the directional valve is to use the movement of the valve core relative to the valve body, control the direction of liquid flow through the change of position, and turn on or off the oil circuit of the directional valve, so as to change the direction of movement, start or stop the actuator. Generally, according to the different control directions, it can be divided into manual directional valves, motorized directional valves, electromagnetic directional valves, electro-hydraulic directional valves and other types.

Manual directional valve is a common hydraulic component, its main role is to control the flow direction of hydraulic oil in the hydraulic system. The working principle of the manual directional valve is to change the flow channel inside the valve by manually operating the valve, so as to realize the flow direction control of the hydraulic oil. The manual directional valve is usually composed of valve body, valve, spring, sealing ring and other parts, the valve is the core component of the manual directional valve, its position determines the flow direction of the hydraulic oil, when the valve is in a position, the hydraulic oil can flow smoothly through the valve, and when the valve is manually operated to change the position, the flow direction of the hydraulic oil will also change. When the manual directional valve is in the neutral position, the hydraulic oil can flow freely through the valve without being obstructed or changing the flow direction, and the hydraulic oil in the hydraulic system can flow freely to each hydraulic component to achieve the normal operation of the hydraulic system.

Motorized directional valve, also known as ironmaking equipment stroke valve, uses a stop or cam installed on the moving parts, and the roller at the end of the pressure valve spool moves the valve core, so that the oil circuit is turned, this kind of valve is usually a two-position valve, and is returned with a spring. The valve port is gradually closed or opened when the directional valve of the simple reversing mechanism is reversed, so the reversing is stable and reliable, and the position accuracy is high, and it is often used to control the formation of moving parts or the conversion of fast and slow speeds, and its disadvantage is that it must be installed near the moving parts, and the general tubing is longer.

The solenoid directional valve is an important part in the hydraulic station, which is composed of an electromagnet, a valve core, a spring and a valve body. When the solenoid directional valve is not energized, the spring presses the spool downwards to connect the spool to the outlet of the body, which is isolated from the inlet of the body. When the electromagnetic directional valve is energized, the electromagnet generates a magnetic field, and the action of the magnetic field causes the valve core to be attracted, so as to overcome the pressure of the spring, and the valve core moves upward. When the spool moves up, the spool is disconnected from the outlet on the valve body, and the spool is connected to the inlet on the valve body, so that the liquid can enter the valve body from the inlet and flow out from the outlet, when the electromagnetic directional valve is de-energized, the pressure of the electromagnet no longer produces the magnetic field spring to regain dominance, pressing the spool back into place. Through continuous power-on and power-off operations, the solenoid directional valve can realize the reversing control of the liquid, so as to realize the normal operation of the hydraulic system.

The electro-hydraulic directional valve is a hydraulic reversing valve integrated with the pilot valve of electromagnetic control, which is used to control the pressure oil in the oil circuit to push the valve core, and the electro-hydraulic reversing valve and the hydraulic reversing valve are mainly used in the hydraulic system where the flow exceeds the allowable range of the normal operation of the electromagnetic reversing valve, to control the action of the actuator, or to control the flow direction of the oil. When the two solenoid valve coils are energized, the balance hole circuit is closed, the flow limiting hole circuit is opened, the piston upper cavity is pressurized, the piston goes up, and the valve is opened. Otherwise, the piston goes down and the valve closes. In the process of valve opening and closing, the flow rate and flow signal and the valve plug position signal can be transmitted to the computer, and the corresponding instructions are issued after computer processing, and the energizing and power-off states of the two electromagnetic pilot valves are controlled, so that the hydraulic difference between the upper and lower chambers of the piston changes, so that the piston is controlled at the required opening height and the flow rate of the pipeline medium is controlled.

The above is an introduction to the working principle of several common directional valves, if you are interested in directional valves or have needs, welcome to contact us, we will be happy to answer your questions.


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