Pipe (fluid conveyance)

A tube is an elongated hollow body, the length is typically much greater than its diameter. As opposed to a tube, a tube of a relatively inflexible material has been manufactured.

Use

Tubes generally have a circular cross -section, which is the optimum design for the most common applications. For use as a static element with increased stiffness they are manufactured with rectangular, oval and other cross-sections.

Tubes can be used for the following functions:

  • As a transport route of a pipeline for liquids, gases, or free flowing solids
  • As a constructive element in engineering, for example, as axes or shafts
  • As a static element, for example in the form of a lattice frame
  • Semi-manufactured for various applications, such as shock absorber
  • As a transport route of a pneumatic tube system

Bends to a straight pipe using a pipe bender, then a pipe bend.

The areas where a tube is determined by its properties, such as cross section, material, surface finish, diameter (DN) and pressure rating (PN).

Materials and Preparation

Pipes are made ​​of various materials ( eg, steel, ceramics, light metal, plastic) and are not usually flexible ( as opposed to the tube).

Metal pipes are manufactured today with either a welded seam or seamless. The winding a sheet metal strip into a tube ( spiral duct ) is particularly widespread in the ventilation area.

Welded tubes

Tubes with thin walls in proportion to their outer diameter are usually manufactured as welded tubes. For the welding of pipes, a hollow body is first prepared by bending or rolling of sheet, which is then welded at the joints. Tubes up to about a meter in diameter can be welded longitudinally, spirally welded, larger pipes and large pipes bent from heavy plate and welded in pieces.

  • Tubes up to a diameter of about 200 mm in thick walls are normally produced seamlessly. The hitherto most used ( for non-ferrous metals) method is based on that a red-hot output piece - block or bolt called - made ​​of brass, copper, steel, etc. by means of a hydraulic press by an annular tool - called die - is pressed ( extrusion). Copper tubes and steel must be cooled immediately thereafter rapidly in water. The length of the extruded tubes is generally less than 50 m. The tube here is wavy and soft, easily bendable, its dimensions are inaccurate.
  • Newer methods of production of seamless tubes aim to continuously produce pipes as long as possible. The procedures for making are already been used in similar form in the wire manufacturing, initially by means of a continuous casting non-ferrous pipe is formed, which is then reduced directly by rolling in diameter.
  • Because it is rotationally symmetrical components in tubes, they may also be produced by centrifugal casting.
  • The production and processing of seamless tubes can also be performed by plastic deformation, eg by extrusion (plastic ), forward rolls, stopper rollers, stretch-reduction, push bench process or, particularly in back-step process.
  • In further process steps, the tubes are often further processed by drawing, to achieve certain diameter, wall thickness, material strength and surface qualities. The finished tubes with larger diameters in standard lengths ( widely used eg 6 m ) were cut. Tubes with small diameters usually arrive at so-called ' coils ' wrapped in the trade.
  • The patent on the first process for the production of seamless steel tubes received in 1885 the Mannesmann brothers.

The following materials are used:

  • Steel
  • Stainless steel
  • Cast iron (in this case, the production by casting ).
  • Copper
  • Brass
  • Nickel alloys, titanium alloys, aluminum alloys,
  • Combination of plastic and metal ( composite pipe )
  • Combination of glass and metal (email)
  • And in rare cases - in historic buildings or in old buildings - Lead
  • Plastic
  • Concrete and reinforced concrete
  • Resin concrete
  • Fiber cement
  • Ceramics
  • Wood ( Teuchel or Deichel )
  • Basalt
  • Sound
  • Stoneware

Plastic pipes ( eg, polyethylene pipe ) are important in areas such as sanitation, drinking water and gas supply, cable protection, agriculture and industry. They have advantages over other materials such as aluminum, concrete, cast iron, copper and steel. Due to their light weight, resistance to corrosion and chemicals, as well as the easy handling their importance is increasing in all areas of application. Market researchers expect global sales of over 80 billion U.S. $ in 2019. On the European market, sales will amount in 2020 to about 12.7 billion euros.

Steel Pipes

Plastic pipes

, Folded lead pipes of a Roman bath seams

Compounds

The connections are screwed, soft or hard soldered, welded, glued, pushed by sealing each other, clamped by the clamping ring, only inserted or pressed. There are also compression fittings.

Connection options are welded and brazed joints, flanges, couplings, pipe fasteners, rolled in, clamping rings, molded parts, fittings and pre-bent pipe sections. Typical fittings are tees, bends 45 °, 90 ° and 180 °, as well as concentric and eccentric reducers.

To connect pipes of different materials is often difficult, as the two metals form a galvanic element and often corrode at the junction.

Processing

In addition to simply cutting by sawing or pipe cutter tubes are processed in increasingly complete on tube laser machines.

Dimensions

In conjunction with a standard nominal diameter are (DN = Nominal Diameter ) information about the dimensions of the pipe (inner diameter (ID = Inside Diameter), outer diameter ( OD = Outside Diameter ), wall thickness). These are different depending on the standard.

There are a number of pipe standards for a variety of applications. The following tables give an example information about the dimensions (in mm) of pipes according to DIN, ISO and ASME:

Axle Space frame Aluminium Stoneware#History and notable examples Rabbet Gasket Sleeve (construction) Galvanic cell Pipecutter
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