This article summarizes some of the different types of connectors designed for use in pneumatic systemss. For background on plastic connectors used in pneumatics, click here.
Stainless-steel pneumatic fittings
NITRA pneumatics products now include a range of stainless-steel fittings that stand up to harsh chemicals and washdown situations. Available in NPT inch and BSPT (metric) sizes, the push-to-connect male fittings are made with 316 stainless-steel bodies and 303 stainless gripping collets with internal Viton O-rings. The rugged fittings withstand pressures to 290 psi and temperatures to 390°F. The fittings can be used with polyurethane, nylon, and PTFE tubing among others. Styles include straight unions, males, and reducers; bulkhead fittings; and elbows and tees that can be rotated after installation to allow for variations in piping direction.
AutomationDirect, (800) 633-0405,
Acetal push-in fittings
MB fittings are made of acetal polymer resins, making the line stiff, corrosion and fatigue resistant, and dimensionally stable — all characteristics necessary to bridge the gap between metal connectors and ordinary plastic fittings. The MB’s push-in design enables quick, manual connection and disconnection with pneumatic lines. A stainless-steel collet grips and holds the tube captive, while an inner O-ring ensures a tight connection. Pressing the release ring frees the tube from the fitting. MB fittings are compatible with PA6, PA11, PA12, and polyurethane tubing. Temperature range is -20 to 70°C and pressure range is 15 bar to 750 mm-Hg vacuum.
C.Matic, +39 0362 805246
eSafe is a new safety coupling said to offer high flow combined with a low pressure drop. eSafe is a one-hand operated, compact coupling that vents before disconnection to eliminate the risk of hose-whip and keep the operator from harm. In addition, it has a low connecting force and easy-to-grip design. The durable coupling resists impact, vibration, and swiveling and has the same dimensions as standard couplings. It complies with ISO 4414 and EN 983 standards.
CEJN Industrial Corp., (847) 263-7200
A twin-ferrule, stainless-steel design and precision manufacturing ensure leak-free connections despite high pressure or extreme vacuum. The back ferrule damps vibrations, while the front ferrule circumferentially seals the surface between the tube and coupling. A deep pipe bore and entry taper guarantee accurate positioning and centering of the tube, and the fitting can be used multiple times. Parts can also be supplied in Hastelloy, titanium, and other high-alloy materials.
Schwer Fittings GmbH, +49 7424 98250,
The NPQP Series of polypropylene pneumatic fittings is now made with FDA approved materials. This makes them a lower-cost alternative to stainless steel in food-zone applications. The metric push-pull fittings offer chemical and media resistance comparable to stainless steel, but are lighter and require less force to insert and remove the tubing. The body includes a threaded portion with releasing sleeve, stainless steel tube gripping teeth, and EPDM sealing rings. There are 15 fitting styles and 99 different types for 4 to 12-mm OD tubing. The fittings connect to flexible plastic tubing for a variety of pneumatic applications, including food and beverage, packaging, bio-pharmaceutical, and process.
Festo Corp., (800) 993-3786
Fittings & tubing
Series QR1 fittings are for inch tubing/NPT threads and metric tubing/IS0-G(BSPP)threads. An oval release ring reportedly lets the push-in fittings release from the tubing quicker and easier than with traditional round release rings. The polymer design is lightweight and corrosion resistant, but a stainless-steel tube locking mechanism and captive O-ring ensure reliable sealing. QR1 fittings come in standard and mini sizes, plus function fittings that include ball valves, check valves, and flow controls. Versions include straights, elbows, tees, Ys, Xs, manifolds, bulkheads, plugs, reducers, unions, and caps.
Bosch Rexroth Pneumatics, (859) 254-8031,
Fittings in five materials
Barbed fittings for use with plastic and rubber tubing and reinforced hose are available in polypropylene, polyethylene, nylon, polyvinylidene fluoride (PVDF), and brass. Each offers different performance properties to meet the demands of diverse applications. For example, users can select materials to meet FDA approvals, resist physical stress and abrasion, handle temperature extremes, or UV exposure. Installation involves pushing the Thermobarb fitting into the tubing and securing it with a clamp. Multiple barbs provide a tight fit with tubing IDs from 1⁄8 through 1 in. Styles include tees, Ys, reducers, and adapters.
NewAge Industries, (800) 506-3924
Rugged compression fittings
Corrosion-resistant stainless steel and brass compression fittings provide reliable air tight connections, even when exposed to aggressive fluids or extreme pressures and temperatures; or the circuit requires metal or stiff plastic tubing. Internal ferrules and an O-ring face seal design provide leak-free assemblies. The compression fittings are for use with 4-mm tubing and 1/4-28 threads. M3, M4, 10-32, M5, 1⁄4-20, and 5⁄16-24 thread sizes and 1⁄16, 1/8, 1⁄4-in. OD tubing options are also available.
Beswick Engineering, (800) 354-5014,
A series of flame-resistant fittings and tubing is made from materials that are equivalent to UL 94 V-0 for a variety of industrial applications. KR Series fittings and KRM Series manifolds have bodies made of flame resistant PBT and are designed for weld-spatter environments. TRTU Series tubing has an outer tube layer of flame-resistant polyolefin, a middle layer of aluminum laminated film, and a polyurethane inner tube. All the components are suitable for air and water service and have temperature ratings up to 140°F.
SMC Corp. of America, (317) 688-0298