Quick connect fitting explained

For hoses and piping, a quick connect fitting, also called a push fitting, is a coupling used to provide a fast, make-or-break connection of gas or liquid transfer lines. Operated by hand, quick connect fittings replace threaded or flanged connections, which require wrenches. When equipped with self-sealing valves, quick connect fittings will, upon disconnection, automatically contain any fluid in the line.

Uses

There is a large variety of quick connect fittings. They are used underwater, in drilling operations, in outer space, and for pneumatic-power, plumbing, heating, electrical, and fire-suppression applications. Quick connect fittings are intended to be applied more easily than traditional fittings, requiring only that that pipes be pushed together firmly to lock the teeth of the fitting firmly. The teeth are forced deeper into the tubing when opposing force is applied to them, preventing their separation from the tubing. An o-ring provides a water-tight and airtight seal.^{[1] [2] [3]}

Types

Fittings come in a variety of generic and proprietary types, with market dominance highly dependent on global region.^[4]

North America:

• Industrial-type interconnect/interchange, based on military specification MIL-C-4109F.^[5]
• ARO-type interconnect/interchange, compact and lightweight fittings developed by ARO (now part of Ingersoll-Rand), mainly for precise pneumatic applications.^[6]
• Automotive-type interconnect/interchange, based on a standard set forth by the pneumatic machinery firm Tru-Flate for automotive shops, including tire inflation and pneumatic tools.^[7]

Europe:

• European standard, also known as the Highflow European standard.
• British standard

Japan:

• Nitto standard

Cost

Unit cost varies from a few dollars for mass-produced compressed air couplings to $1 million for large-bore couplings used in the ship-to-shore transfer of liquified natural gas.

See also

• Air-line fitting
• Hose coupling
• Fitting

Notes and References

1. Web site: Patent Database Search Results: "push to connect" in US Patents Text Collection. patft.uspto.gov. 2018-09-18. 2021-10-01. https://web.archive.org/web/20211001040040/https://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.htm&r=0&f=S&l=50&d=PTXT&RS=%22push+fit%22&Refine=Refine+Search&Query=%22push+to+connect%22. live.
2. Quick connect technology inventor, David B. Crompton - USPTO.GOV
3. Original U.S. quick connect invention
4. Web site: Deciphering air fittings and coupler standards Helping you work smarter not harder. admin. en-US. 2019-07-13. 2019-07-05. https://web.archive.org/web/20190705165724/http://rtstools.com/deciphering-air-fittings-and-coupler-standards/. live.
5. MIL-C-4109F (AMENDMENT 1), MILITARY SPECIFICATION, COUPLING HALVES, LOW PRESSURE, AIR HOSE, QUICK-DISCONNECT (29 JUN 1992) http://everyspec.com/MIL-SPECS/MIL-SPECS-MIL-C/MIL-C-4109F_AMENDMENT-1_11048/
6. Web site: Air Couplers: An In-Depth Guide . Myers . David . 16 October 2023 . Movieweb . 9 August 2024.
7. Kostelnicek, Dick. "Quick-Connect Pneumatic Couplers". Home Metal Shop Club, Volume 8 Number 8 http://www.homemetalshopclub.org/news/aug03/aug03.html