Pipe (fluid conveyance)
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 (fluids), slurries, powders and masses of small solids.
In common usage the words pipe and tube are usually interchangeable, but in industry and engineering, the terms are uniquely defined.
Pipe assemblies are almost always constructed with the use of fittings such as elbows, tees, and so on, while tube may be formed or bent into custom configurations.
[3] One of them, Henry Osborne, developed a relatively effective process in 1817 with which he started to make iron gas tubes ca.
Advances since the 1970s, in materials, process control, and non-destructive testing, allow correctly specified welded pipe to replace seamless in many applications.
LSAW are made by bending and welding wide steel plates and most commonly used in oil and gas industry applications.
Due to their high cost, LSAW pipes are seldom used in lower value non-energy applications such as water pipelines.
Pipe is made out of many types of material including ceramic, glass, fiberglass, many metals, concrete and plastic.
Inconel, chrome moly, and titanium steel alloys are used in high temperature and pressure piping in process and power facilities.
In the US it is estimated that 6.5 million lead service lines (pipes that connect water mains to home plumbing) installed before the 1930s are still in use.
[9] Plastic tubing is widely used for its light weight, chemical resistance, non-corrosive properties, and ease of making connections.
Plastic materials include polyvinyl chloride (PVC),[10] chlorinated polyvinyl chloride (CPVC), fibre reinforced plastic (FRP),[11] reinforced polymer mortar (RPMP),[11] polypropylene (PP), polyethylene (PE), cross-linked high-density polyethylene (PEX), polybutylene (PB), and acrylonitrile butadiene styrene (ABS), for example.
The wall thickness on modern copper is usually thinner than 1⁄16-inch (1.6 mm), so the internal diameter is only "nominal" rather than a controlling dimension.
The pipe size designation generally includes two numbers; one that indicates the outside (OD) or nominal diameter, and the other that indicates the wall thickness.
Pipe installation is often more expensive than the material and a variety of specialized tools, techniques, and parts have been developed to assist this.
The undesired motions may be process derived (such as in a fluidized bed reactor) or from a natural phenomenon such as an earthquake (design basis event or DBE).
If frequent disconnection will be required, gasketed pipe flanges or union fittings provide better reliability than threads.
Developed in the 1920s, these mechanical grooved couplings can operate up to 120 pounds per square inch (830 kPa) working pressures and available in materials to match the pipe grade.
When pipes join in chambers where other components are needed for the management of the network (such as valves or gauges), dismantling joints are generally used, in order to make mounting/dismounting easier.
A broad variety of standardized pipe fittings are available; they are generally broken down into either a tee, an elbow, a branch, a reducer/enlarger, or a wye.
In some cases, where care has been taken in the manufacture, storage, and installation of pipe and tubing, the lines are blown clean with compressed air or nitrogen.
Steel pipe is still used in many homes and businesses to convey natural gas or propane fuel, and is a popular choice in fire sprinkler systems due to its high heat resistance.
Soft copper is the most popular choice for refrigerant lines in split-system air conditioners and heat pumps.
Solder-connected rigid copper is the most popular choice for water supply lines in modern buildings.
In situations where many connections must be made at once (such as plumbing of a new building), solder offers much quicker and much less expensive joinery than compression or flare fittings.
A disadvantage in compression connections is that they take longer to make than sweat, and sometimes require retightening over time to stop leaks.
Thousands of pounds-force per square inch of pressure are used to deform the fitting and compress the sealant against the inner copper tubing, creating a watertight seal.
Advantages of this method are: Disadvantages are: Aluminium is sometimes used due to its low cost, resistance to corrosion and solvents, and its ductility.
Aluminium tubing can be connected by flare or compression fittings, or it can be welded by the TIG or heliarc processes.
Tempered glass pipes are used for specialized applications, such as corrosive liquids, medical or laboratory wastes, or pharmaceutical manufacturing.
