Pneumatic fittings are parts used to connect sections of pipe, tube, and hose in pneumatic (pressurized gas) systems. Compared to hydraulic fittings, pneumatic fittings are typically characterized by tighter seals and lower pressure requirements. They are frequently used in pneumatic logic control systems and instrumentation. Pneumatic tube fittings create connections and filter air in pneumatic systems. Pneumatic inline and tee filters remove unwanted particles from airflow.
It is important to distinguish what type of vessels are being connected in the system to determine what fittings are appropriate.
Pneumatic fittings are attached via a number of different connection methods, each with its own conveniences and advantages.
Ball and sleeve fittings connect an outer sleeve to an inner-ball fitting. The sleeve retracts to connect and disconnect the two ends of the fitting. Some ball and sleeve fittings function as push-to-connect fittings which are convenient for applications requiring frequent disconnection and re-connection of the hose section.
Crimp fittings involve placing hose over a tubular end and crimping against it with a sleeve, ring, or crimp socket. These fittings typically require crimping tools or machines to make the connections.
End fittings provide specific surfaces for connecting vessels in pneumatic systems.
Push-to-connect fittings have ends that are designed to accept tubing by pushing it into the end. These fittings typically disconnect via some type
of collar retraction. These connections are convenient for sections of the system requiring frequent disconnection and re-connection.
Threaded fittings have screw threads (built-in grooves) on their inner (female) or outer (male) surfaces designed to accept connections with matching threads. Threads which provide a simple connection but no guaranteed seal are called straight threads. Tapered threads are designed to provide a tight seal which is important for pneumatic applications. These precise threads create a “dry fit”, meaning they seal without the need for an additional sealant, which is important in applications where sealant addition could cause contamination or corrosion.