Pneumatic Valve

What is a pneumatic directional control valve?

Pneumatic directional control valves are valves that control the forward and backward movement of cylinders by changing the direction of compressed air. They act as the "brain" of a pneumatic system, determining which cylinder moves and when. The category includes JelPc brand electrically, air-, and mechanically operated 3/2 and 5/2 valves.

What do 3/2 and 5/2 mean?

In valve designations, the first number indicates the number of ports (ways) and the second number indicates the number of positions the valve can take.

• 3/2 valves: Three ports, two positions. Controls single-acting cylinders, air blowing, and vacuum operations.
• 5/2 valves: Five ports, two positions. Controls the forward and backward movement of double-acting cylinders.
• Single-solenoid valves: Return to the initial position by spring when the solenoid is de-energized.
• Double-solenoid valves: Memorize the last signal received; retain their position even when de-energized.
• Air-piloted and mechanical valves: Controlled by an air signal, pedal, lever, or roller instead of electricity.

Selection criteria

Whether the cylinder is single- or double-acting determines the valve type. The control method is selected based on how the system will be managed: solenoid valves are preferred in PLC and sensor-based systems, while air-piloted or mechanical valves are preferred in environments where electricity is undesirable. The connection size (e.g., 1/8 or 1/4 inch) must be large enough to pass the volume of air required by the cylinder. The coil voltage must be selected to match the control circuit.

Installation and maintenance

Fitting silencers to the valve's exhaust ports reduces noise and prevents dirt ingress. Valves have a longer service life when operated with clean, dry air; therefore, a conditioner should be installed at the beginning of the line. In systems with multiple valves, manifold (base plate) mounting organizes wiring and air connections.

Frequently asked questions

Single solenoid or double solenoid?

If the cylinder is required to return to its initial position when power is cut, a single solenoid is preferred; if it is required to hold its last position, a double solenoid is preferred.

The valve is operating but the cylinder is not moving — why?

Air pressure may be insufficient, connections may be incorrectly made, or the cylinder seal may be leaking.

Why is the valve making noise?

Coil vibration or exhaust air can cause noise. Using a silencer reduces exhaust noise.

Where are mechanical valves used?

They are used in applications requiring control by pedal, lever, or roller where electricity is not used.

Is the coil sold separately?

The coil is replaceable on some models. Pay attention to voltage and size compatibility.

Where should I look for cylinder selection?

Browse the pneumatic cylinders category for suitable cylinders.