What are Directional Control Pneumatic Valves

The best way to change airflow directions in pneumatic control systems is with a directional control valve. These valves have a moving part that disconnects and connects internal flow passages (in the pneumatic valve body). The result of this action is complete control of the direction of airflow.

Typically, directional pneumatic control valves are built with four separate internal passages within a single sliding spool and valve body.

By shifting spools alternately, the cylinder connects to a cylinder port that supplies pressure and functions as an exhaust port. When a spool is set up to provide pressure by being connected to port A and B (connected to the exhaust port), cylinders will extend. As the spool moves to the other extreme, the cylinder begins to retract.

By looking at the flow paths set up in various operating conditions, you can classify the type of directional control valves needed. It would help if you account for the exact number of individual ports, the number of internal connection ports, and the number of flow paths.

Pneumatic Valves

Standard directional valve options include:

Two-Way Directional Valve: consists of two ports that relate to passages, and they have an on/off function.

Three-Way Directional Valve: consists of three ports that are connected through passages in the valve body. Their primary function is to exhaust and pressurize a single actuator port.

Four-Way Directional Valve: consists of four separate flow paths in the valve body. They are commonly used to create reversible motion.

Pneumatic Controls

• Understanding the Three Types of Pneumatic Control Valves
  Control valves are used to control the flow of air strictly. The most common examples of these tools at work include flow control valves, non-return valves, and shuttle valves.
• Top Safety Protocols for Using Pneumatic Control Systems
• A Guide to Control Pneumatic Energy