Push in, push to connect, push fit, push and pull or instant fittings all refer to easily removable, quick connect or compression fittings. This type of fitting facilitates the attachment of an air (or water) line, without requiring the use of any additional tools apart from those necessary for pipe cutting. These fittings behave in a similar way to ordinary compression fittings, but employ a resilient O-ring to form the seal, plus a grip ring to keep the tube in place.
Push-in fittings are commonly used where a simple, fast connection is desired for a low-pressure pneumatic application. Hoses can simply be pushed into, or pulled out of the fitting without any major operation being required. They are available in several different styles, including those made of polymer and those made of nickel-plated brass. Polymer push in fittings are generally sturdy and rigid, dimensionally stable and resistant to fatigue and corrosion. The nickel-plated brass variety allow quick and simple manual connections to calibrated plastic hoses, whenever and wherever in the pneumatic circuit the connection is required.
Different connection types include male and female studs or bulkheads, straight, Y, T, cross and elbow configurations, plugs, caps and tubes. Specially designed fittings can include ball valves, flow controllers and adaptors. Some connectors have a grooved grip ring for additional connectivity between metal and plastic connections. Retaining rings secure hoses tightly and reliably and can be released easily by pressing a release ring while pulling the hose out.