Pneumatic fittings are used to connect sections of pipe, tube and hose in pressurized gas systems. Compared to hydraulic fittings, pneumatic fittings are generally characterized by tighter seals and lower pressure requirements. They are often utilized in pneumatic logic control systems and instrumentation.
Pneumatic Pipes, Tubes and Hoses
Hoses are flexible vessels. They are constructed of multiple layers of different materials. Since the hose itself is typically replaced in time due to wear, fittings for hoses are usually not permanent.
Pipes are rigid vessels. They are constructed of one solid material. Typically, pipes are defined by their inner diameter dimension.
Tubes are fairly rigid vessels. They are constructed of one solid material. Tubes are typically defined by their outside diameter dimension.
Types of Pneumatic Fittings
Pneumatic fittings are attached with numerous different connection methods, each with its own conveniences and advantages.
Ball and Sleeve Fittings
The outer sleeve is connected to the inner (ball) fitting via the ball and sleeve fittings. The outer sleeve retracts to connect and disconnect the two ends of the fitting. Some of these fittings function as push-to-connect fittings which are great for applications requiring frequent disconnection and re-connection of the hose section.
All types of fittings which use compressive force to connect the vessel to the fitting are classified as compression fittings.
Standard Compression Fittings
These type of fittings utilize metal baskets, rings or ferrules which form a seal on the vessel through compression. Generally, the compression is made by tightening a nut onto the fitting over the piping and ferrule, compressing and securing the vessel inside. Standard compression fittings do not require tools to assemble, which makes them great for quick field installations.
These are compressive fittings with a sharpened ferrule that “bites” the vessel when compressed and provides the seal. Similar to standard compression fittings, bite-type fittings require no special tools to assemble, but provide a stronger, higher pressure connection.
Mechanical Grip Fittings
Mechanical grip fittings are two-ferrule assemblies. The back ferrule grips the vessel while pressing up against the front ferrule, spring-loading the front ferrule and makes a seal between the piping and fitting body. These fittings can be reassembled multiple times without damaging components or piping. They have great resistance to mechanical vibration.
These type of fittings have a body with a flared or coned end. Special flaring tools are utilized to install the vessel inside the flared end, which provides a deep seal. Compared to standard compression fittings, flared fittings can handle higher pressures and a wider range of operating parameters.
Crimp fittings require placing hose over a tubular end and crimping against it with a sleeve, ring or crimp socket. Generally, these fittings involve crimping tools or machines to make the connections.
Specific surfaces are provided by end fittings for connecting vessels in pneumatic systems.
These type of fittings consist of ends that are designed to accept tubing by pushing it into the end. Generally, these fittings disconnect via some type of collar retraction. These connections are great for sections of the system requiring frequent disconnection and re-connection.
Threaded fittings consist of screw threads (built-in grooves) on their inner (female) or outer (male) surfaces designed to accept connections with matching threads. Straight threads are threads that provide a simple connection but no guaranteed seal. Tapered threads are designed to provide a tight seal which is critical for pneumatic applications. A “dry fit” is created by these precise threads, which means they seal without the need for an additional sealant. This is why it is important in applications where sealant addition could cause contamination or corrosion.
Don’t hesitate to contact Bryan Hose & Gasket with the link below for more information or to purchase your pneumatic fittings today!