
In
piping and
plumbing
Plumbing is any system that conveys fluids for a wide range of applications. Plumbing uses pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids. Heating and cooling (HVAC), waste removal, and potable water delivery ...
, a coupling (or coupler) is a very short length of
pipe or
tube
Tube or tubes may refer to:
* ''Tube'' (2003 film), a 2003 Korean film
* ''The Tube'' (TV series), a music related TV series by Channel 4 in the United Kingdom
* "Tubes" (Peter Dale), performer on the Soccer AM television show
* Tube (band), a ...
, with a socket at one or both ends that allows two pipes or tubes to be joined,
welded (
steel
Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...
),
brazed
Brazing is a metal-joining process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, with the filler metal having a lower melting point than the adjoining metal.
Brazing differs from we ...
or
soldered (
copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
,
brass
Brass is an alloy of copper (Cu) and zinc (Zn), in proportions which can be varied to achieve different mechanical, electrical, and chemical properties. It is a substitutional alloy: atoms of the two constituents may replace each other with ...
etc.) together.
Alternatively it is a short length of
pipe with two
female
Female (Venus symbol, symbol: ♀) is the sex of an organism that produces the large non-motile ovum, ova (egg cells), the type of gamete (sex cell) that fuses with the Sperm, male gamete during sexual reproduction.
A female has larger gamet ...
National pipe threads (NPT) (in North American terms, a coupler is a double female while a nipple is double male) or two male or female
British standard pipe thread
British Standard Pipe (BSP) is a set of technical standards for screw threads that has been adopted internationally for interconnecting and sealing pipes and fittings by mating an external (male) thread with an internal (female) thread. It has b ...
s.
If the two ends of a coupling are of different standards or joining methods, the coupling is called an adapter. Examples of adapters include one end BSP threaded with the other NPT threaded, and one end threaded with the other a plain socket for brazing.
A coupling whose ends use the same connection method but are of different sizes is called a reducing coupling or
reducer
A fitting or adapter is used in pipe systems to connect straight sections of pipe or tube, adapt to different sizes or shapes, and for other purposes such as regulating (or measuring) fluid flow. These fittings are used in plumbing to manipulate ...
. An example is a 3/4" NPT to 1/2" NPT coupling.
See also
*
Closet flange {{Unreferenced section, date=May 2021
In plumbing, a closet flange (also known as a toilet flange) is a pipe fitting (specifically, a type of flange) that both mounts a toilet to the floor and connects the closet bend to a drain pipe. The name ...
*
Eccentric reducer An eccentric reducer is a fitting used in piping systems between two pipes of different diameters. The same fitting can be used in reverse as an eccentric increaser or expander. They are used where the diameter of the pipe on the upstream side of t ...
*
Nipple (plumbing)
In plumbing and piping, a nipple is a fitting, consisting of a short piece of pipe, usually provided with a male pipe thread at each end, for connecting two other fittings.
The length of the nipple is usually specified by the overall length with ...
*
Piping and plumbing fittings
A fitting or adapter is used in pipe systems to connect straight sections of pipe or tube, adapt to different sizes or shapes, and for other purposes such as regulating (or measuring) fluid flow. These fittings are used in plumbing to manipulate ...
*
Reducer
A fitting or adapter is used in pipe systems to connect straight sections of pipe or tube, adapt to different sizes or shapes, and for other purposes such as regulating (or measuring) fluid flow. These fittings are used in plumbing to manipulate ...
*
Street elbow
A street elbow (sometimes called a street ell or service ell) is a type of plumbing or piping fitting intended to join a piece of pipe and another fitting at an angle. The difference between a street elbow and a regular elbow is the gender of its ...
Further reading
*ASME B1.20.7 Hose Coupling Screw Threads, Inch. (Quote: ''The normal sequence of connections, in relation to the direction of flow, is from an externally threaded nipple into an internally threaded coupling'')
External resources
PDF illustrating assorted adapters
Piping
Plumbing
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