Coupling (piping)
Encyclopedia
A coupling (used in piping
or plumbing
) is a very short length of pipe
or tube, with a socket
at one or both ends that allows two pipes or tubes to be joined, welded
(steel
), brazed
or soldered
(copper
, brass
etc.) together.
Alternatively it is a short length of pipe
with two female
National pipe thread
s (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
s.
If the two ends of a coupling are different (e.g. one BSP threaded and one NPT threaded), then it is usually referred to as an adapter. Another variation is one plain socket and one threaded socket. Yet another variation would be 3/4" NPT to 1/2" NPT.
When the two ends use the same connection method but are of a different size, the terms reducing coupling or reducer
are used.
Piping
Within industry, piping is a system of pipes used to convey fluids from one location to another. The engineering discipline of piping design studies the efficient transport of fluid....
or plumbing
Plumbing
Plumbing is the system of pipes and drains installed in a building for the distribution of potable drinking water and the removal of waterborne wastes, and the skilled trade of working with pipes, tubing and plumbing fixtures in such systems. A plumber is someone who installs or repairs piping...
) is a very short length of pipe
Pipe (material)
A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases , slurries, powders, masses of small solids...
or tube, with a socket
Socket
Socket may refer to:In mechanics:* Socket wrench, a type of wrench that uses separate, removable sockets to fit different sizes of nuts and bolts...
at one or both ends that allows two pipes or tubes to be joined, welded
Welding
Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, with pressure sometimes...
(steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
), brazed
Brazing
Brazing is a metal-joining process whereby a filler metal is heated above and distributed between two or more close-fitting parts by capillary action. The filler metal is brought slightly above its melting temperature while protected by a suitable atmosphere, usually a flux...
or soldered
Soldering
Soldering is a process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, the filler metal having a lower melting point than the workpiece...
(copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
, brass
Brass
Brass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...
etc.) together.
Alternatively it is a short length of pipe
Threaded pipe
A threaded pipe is a pipe with screw-threaded ends for assembly.- Tapered threads :The threaded pipes used in some plumbing installations for the delivery of gases or fluids under pressure have a threaded section that is slightly conical . This is called a "tapered thread"...
with two female
Gender of connectors and fasteners
In electrical and mechanical trades and manufacturing, each half of a pair of mating connectors or fasteners is conventionally assigned the designation male or female...
National pipe thread
National pipe thread
National Pipe Thread Tapered Thread is a U.S. standard for tapered threads used on threaded pipes and fittings. The taper rate for all NPT threads is measured by the change of diameter over distance. The angle between the taper and the center axis of the pipe is 1° 47′ 24″...
s (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 thread
The British Standard Pipe thread is a family of standard screw thread types that has been adopted internationally for interconnecting and sealing pipe ends by mating an external with an internal thread.-Types:...
s.
If the two ends of a coupling are different (e.g. one BSP threaded and one NPT threaded), then it is usually referred to as an adapter. Another variation is one plain socket and one threaded socket. Yet another variation would be 3/4" NPT to 1/2" NPT.
When the two ends use the same connection method but are of a different size, the terms reducing coupling or reducer
Reducer
A reducer is the component in a pipeline that reduces the pipe size from a larger to a smaller bore .The length of the reduction is usually equal to the average of the larger and smaller pipe diameters...
are used.
See also
- Closet flangeCloset flangeIn plumbing, a closet flange is a pipe fitting that both mounts a toilet to the floor and connects the toilet drain to a drain pipe. The name comes from the term "water closet", the traditional name for a toilet. A typical closet flange is composed of an ABS or PVC hub with a round steel...
- Nipple (plumbing)Nipple (plumbing)In plumbing and piping, a nipple is a fitting, consisting of a short piece ofpipe, usually provided with a male pipe thread at each end, for connecting two other fittings....
- Piping and plumbing fittingsPiping and plumbing fittingsFittings are used in pipe and plumbing systems to connect straight pipe or tubing sections, to adapt to different sizes or shapes, and for other purposes, such as regulating or measuring fluid flow...
- ReducerReducerA reducer is the component in a pipeline that reduces the pipe size from a larger to a smaller bore .The length of the reduction is usually equal to the average of the larger and smaller pipe diameters...
- Street elbowStreet elbowA street elbow 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 nature of the connections on either end.A regular elbow has a female hub or FIP connection on both ends...
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)