Luer Fittings & Connectors – In General

Luer fittings are used extensively in medical and life sciences applications.  But there is a tremendous amount of confusion about what these fittings really are.  The” Luer Taper” is named after Hermann Wülfing Luer who was a German instrument maker working in France on the development of tapered glass bottle stoppers, and glass syringes.   The result of his research and development was a conical 6% taper that produces a quick tight sealing connection between male and female mating surfaces.  Mostly relegated today to the antique stores and museums are the glass stopper apothecary bottles of old, but his design is still as useful and relevant today as it was in the late 1800s.  At its most basic level, a Luer fitting is defined as a small-bore, friction based, leak-proof connector.   Its prominent use is to connect tubing and equipment for the transfer of fluids and gases.

Currently there are two categories or types of Luer fittings in use.  The slip Luer based on the original design, and the Luer lock based on a design improvement made by  Fairleigh S. Dickinson in the early 1900s.  Mr. Dickinson working on what would become the “Becton-Dickinson Yale Luer-Lok Glass Syringe” added a twist­-lock mechanism to hold the hypodermic needle safely in place. It was a simple way to attach and to remove a needle from a glass syringe, minimizing the danger of the needle slipping off the tip while in use, as well as reducing the breakage of the syringe tip.  The male and female slip Luer fittings, as the name implies, simply slip together to form a seal.   Luer lock fittings have the addition of interlocking threads to hold the connection together.   The male Luer lock has an external housing with internal threads, while the female Luer lock has the addition of an external thread added at the base of the taper.  These threads draw the two fittings together, tightening the seal, while providing a mechanical attachment for the two elements of the connection.  The result is a secure leak-proof connection that can be easily taken apart by untwisting the two fittings to disengage the threads.

Luer fittings form the nucleus of an extremely versatile family of connectors.  They are widely used in laboratories, medical devices and intervention therapies.  Some examples are gas chromatography, cell research, intravenous catheters, feeding tubes, ventilators, and the common hypodermic syringe.  Luer fitting are available in a variety of materials and configurations.   Materials such as nylon, polycarbonate, polypropylene, PEEK and stainless steel are readily available.  Both male and female Luer taper fittings can readily configured to work with threaded connections, fractional barb fittings, and ultra small tubing such as Tygon®Microbore tubing.

In summary, the term Luer represents a type of connection rather than a brand or manufacturer.  The fitting consists of a 6% conical taper that precisely mates to its male and female counterpart forming a tight, leak-proof, connection that can easily be disconnected when desired. They are available in a variety of materials and configurations making them extremely versatile for use in a myriad of applications.  While primarily used in the life sciences, they may be the perfect fitting for your next project.

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