Stop Fittings
What Is a Stop Fitting?
A stop fitting is a functional type of one-touch fitting used in pneumatic piping where airflow needs to be automatically blocked when the tube is released.
When the tube is inserted and securely connected, compressed air can flow through the fitting.
Once the tube is released, the internal structure automatically blocks the airflow, helping reduce sudden air discharge from the piping.
Stop fittings are commonly used in piping locations that require partial maintenance, module replacement, or frequent tube removal.
They can reduce the need to shut off the entire main air line for each operation.
Stop Fitting Specifications and Type Selection
Stop fittings are selected according to tube size, thread specification, connection type, fitting shape, operating function, and compatible tubing.
The tube connection end should be confirmed according to the metric tube outside diameter.
If the fitting has a threaded end, the thread specification of the equipment, valve, or pneumatic component port should also be confirmed.
| Selection Criteria | Details |
|---|---|
| Tube Size (mm) | Ø4, Ø6, Ø8, Ø10, and Ø12 |
| Thread |
For fittings with threaded ends, select according to the equipment port, valve port, or pneumatic component port. Available in M and PT thread types. |
| Connection Type | Select according to the connection requirement, such as tube-to-tube or tube-to-thread. |
| Fitting Shape | Straight and elbow |
| Operating Function | Air flows when the tube is connected; airflow is automatically blocked when the tube is released |
| Compatible Tubing | Compatible with PU tubing, nylon tubing, and other pneumatic tubing with compatible metric O.D. |
Selection Differences Between Stop Fittings and Regular One-Touch Fittings
Stop fittings and regular one-touch fittings can both be used for pneumatic piping connections, but they differ in airflow status after tube release and in suitable application conditions.
If the piping location requires frequent tube removal, partial disassembly, or module replacement, and air discharge during tube removal needs to be reduced, a stop fitting can be considered.
| Comparison Item | Stop Fitting | Regular One-Touch Fitting |
|---|---|---|
| Airflow status when the tube is released | Automatically blocks airflow at the fitting side | Air in the piping is usually discharged from the fitting side |
| Air shut-off requirement during maintenance | Can reduce the need to shut off the main air line | Usually requires shutting off the corresponding air line |
| Suitable position | Piping points requiring tube removal, module replacement, or frequent disconnection | General pneumatic piping connection points |
Further Reading
→ One-Touch Fittings Overview｜Classification and Selection Criteria
→ Metric One-Touch Fittings｜Metric Tube Size Specification Overview
