Check Valves
What Is a Check Valve?
A check valve is a functional type of one-touch fitting designed to allow compressed air to flow in one direction while preventing reverse flow.
When compressed air flows in the designated direction, the internal valve opens automatically and allows the air to pass through.
If the airflow reverses, the valve closes automatically to prevent compressed air from flowing backward.
Check valves are commonly used in pneumatic lines where airflow must be limited to one direction or reverse flow must be prevented.
Check Valve Specifications and Type Selection
Check valves should be selected based on tube size, thread, connection type, flow direction, and compatible tubing.
The tube connection should be selected according to the outside diameter of the pneumatic tubing used.
For models with a threaded connection, the thread must also match the equipment port, valve port, or pneumatic component port.
Install the check valve according to the arrow marked on the product to ensure airflow in the designated direction.
| Selection Criteria | Details |
|---|---|
| Tube Size (mm) | Common sizes include Ø4, Ø6, Ø8, Ø10, and Ø12 |
| Thread |
For fittings with threaded ends, select according to the equipment, valve, or pneumatic component port. Available in M and PT thread types. |
| Connection Type | Select according to the piping connection requirements |
| Flow Direction | Install according to the arrow marked on the product to ensure airflow in the designated direction |
| Compatible Tubing | Compatible with PU tubing, nylon tubing, and other pneumatic tubing with compatible metric O.D. |
Selection Differences Between Check Valves and Regular One-Touch Fittings
Check valves and regular one-touch fittings can both be used for pneumatic piping connections, but they differ in airflow control and application requirements.
A regular one-touch fitting is suitable when the primary requirement is to connect tubing and equipment.
A check valve should be considered when the pneumatic line needs to limit airflow to one direction or prevent compressed air from flowing backward.
| Comparison Item | Check Valve | Regular One-Touch Fitting |
|---|---|---|
| Airflow Direction | Allows airflow only in the designated direction | Allows airflow in both directions |
| Backflow Prevention | Prevents compressed air from flowing backward | Does not provide backflow prevention |
Further Reading
→ One-Touch Fittings Overview｜Classification and Selection Criteria
→ Metric One-Touch Fittings｜Metric Tube Size Specification Overview
