The Basic Working Principle of Pneumatic Directional Valve

The basic working principle of pneumatic directional valve:

Control signal: Pneumatic directional valves are usually driven by a pneumatic control signal, which can be manually controlled or part of an automatic control system (such as PLC).

Valve core and seat: The directional valve has one or more valve cores inside, which can move within the valve body to control the flow of compressed air. The valve seat is a fixed part that cooperates with the valve core when it moves, and together they determine the on/off of the airflow.

Reversing action: When the control signal (compressed air) is applied to the control chamber of the reversing valve, the valve core will move according to the pressure and direction of the control signal, thereby changing the path of the airflow. This movement causes the intake and exhaust ports of the pneumatic actuator to be interchanged, achieving a change in the direction of movement of the actuator.

Neutral function: In some directional valve designs, the valve core can simultaneously cut off or connect two working chambers when in neutral position, depending on the neutral function of the directional valve. The difference in median function will affect the state of the pneumatic system when it stops.

Spring reset: In the absence of a control signal, the valve core is usually reset to its initial position by spring force, which ensures that the system can safely return to the preset state when the control signal is lost.

Electromagnetic pilot control: In some advanced pneumatic directional valves, electromagnetic pilot control may be used to achieve more precise and rapid control. Electromagnetic pilot control controls the movement of the main valve core through a small solenoid valve.

Pressure and flow control: In addition to directional control, some pneumatic directional valves also integrate pressure and flow control functions, which can adjust the speed and force of pneumatic actuators while reversing.