Pipeline connection

from Wikipedia, the free encyclopedia

Pipeline connections or pipe connections are available for connecting pipe and hose lines of pipe sections, pipe fittings and fittings .

Pipe connections are selected according to operational requirements (detachability of the connection), operating conditions ( pressure and temperature ), medium and material of pipe sections and fittings ( weldability ).

Types of pipe connections

Welded joints

Welded connections of metallic pipe materials are possible for all pressures and temperatures; Welded joints of plastics within the framework of the respective material properties. The connection of semi-crystalline thermoplastics occurs through:

Solder connection

Soldered connections with fittings made of copper are common in heating construction, but have been replaced by press connections made of copper or (externally) galvanized steel since the turn of the millennium . Steel pipes are also ( hard ) soldered less frequently.

Press connections

Press connections are becoming increasingly popular in building services , but also in industrial applications. Fittings and pipes usually consist of stainless steel , galvanized steel (called "C-steel" or carbon steel), copper or composite pipe. With purely metallic systems and the use of temperature-resistant sealing rings, applications in higher temperature ranges ( solar installation ) are also possible.

Flange connections

Flange connections are particularly limited for larger pipe dimensions and high pressures and temperatures.

Flared connection

Flare for smaller pipe diameters can be at the end of the tube around a face plate (flange) are flanged to the outside, which is then pressed by means of a union nut on a cone or a flat sealing surface for copper and steel tubes with thin walls with a special tool. Flare connections are often used to connect thin, chrome-plated copper pipes to the body of mixer taps , provided they are not firmly soldered in (the opposite pipe end is usually connected with a compression fitting ).

Screw connections

Screw connections for medium pressures and temperatures. Traditionally, Whitworth threads are cut onto the pipe ends in heating and sanitary engineering . Pipes and fittings are screwed together until the conical external thread with the parallel internal thread lie against one another in a metal- tight manner. To improve the sealing effect, the external thread is either wrapped with a Teflon-containing sealing tape, glued with sealing compound or traditionally covered with sealing hemp and coated with an oily sealing paste.

Right-angled smooth pipe ends or gunmetal and brass fittings with external thread can also be connected with union nuts into which a sealing ring is inserted. Independent screw connections as well as screw connections of fittings connections and nozzles can either have a flat seal with a sealing ring or a conical seal with a metallic sealing effect. Connections to radiators and associated fittings such as thermostatic valves are now predominantly equipped with the standardized Euro cone , which is compatible with correspondingly shaped connection pieces from various manufacturers.

Flanged connections are more likely to be used for pipe sizes over 1½ "(DN 40) .

Also Schmiegungsdichtungen are metallically sealed and do not require elastic sealing rings.

Screw couplings are coupling pieces that are screwed together. They do not necessarily have to be mounted on threaded pipes.

Dairy pipe fittings

Dairy pipe fittings , as well as TRI-Clamp connections, are used for media from the food, chemical and pharmaceutical sectors.

Cutting ring and compression fittings

Cutting ring and compression fittings for copper, steel, plastic and composite pipes . The clamping is usually achieved by screwing on a union nut with an internal thread, which compresses a clamping ring, which is usually either slotted or consists of soft, deformable copper connections. With purely metallic systems, applications in higher temperature ranges ( solar installation ) and under high pressure ( hydraulics ) are also possible. Plastic and composite pipes that are not made of rigid PVC generally require a support body inside the pipe, which stabilizes the pipe but restricts the free pipe cross-section.

Compression fittings

Crimp screw connections are similar to compression ring or cutting ring screw connections , but here the connection (and at the same time a seal) is made by squeezing a ring or sleeve made of a compressible material (usually an elastic plastic ) around the pipe with a union nut.

Compression sleeve connections

Compression sleeve connections are used on pipes made of cross-linked polyethylene ("PEX"). The pipe ends are widened, a support body is inserted and the sliding sleeve is pushed on with special pliers. The inner diameter is reduced by the support body, but not as significantly as with many compression fittings with support body due to the previous expansion.

Socket connections

All pipe connections in which the ( pointed ) end of the pipe is pushed (possibly also screwed) into the expanded end of a further pipe or a shaped piece or fitting can be referred to as socket connections in the broader sense .

In a narrower sense, a socket connection consists of a widened pipe end into which the end of another pipe with normal dimensions is pushed. Depending on the material, the widening can be done by hand with the help of an expanding device or pliers, a calibration tool ( expander ) or a socket or cup pliers . If necessary, the material must be warmed up or, in the case of (semi) hard copper, softened beforehand by annealing .

Copper and some plastic pipes can also be bent easily and in relatively small radii. With a special collar tool , bores in the pipe can be flared evenly so that branches in the pipe run as socket connections can also be made. With the help of these techniques, fittings and fittings can be dispensed with almost entirely.

At low pressures and temperatures, socket connections can be made purely as plug connections . Specially shaped clamping or sealing rings ensure moderate tensile strength and tightness of the connection. At higher pressures and temperatures, adhesive and soldered connections are used. Plastic pipes made of polypropylene (PP), polyethylene (PE) and PVC-U can also be connected by heating element butt , electrofusion or ultrasonic welding , pipes made of PVC-U can also be connected by gluing .

Cuff connections

Since low pressures and temperatures prevail in sewer pipes, these can also be connected with flexible sleeves, which are known as sleeve seals (e.g. Flex Seal). With the so-called Canada cuff , pipes with different diameters and / or materials can also be connected.

Plug connections

Plug connections are traditionally used in the assembly of sewer pipes. A more recent development are plug-in systems for pressurized pipe systems made of plastic, copper and steel, which are assembled without tools. Metallic retaining claws prevent the connections from slipping apart.

Adhesive connection

Adhesive joints are often used for gas and (cold) water installations as well as for acids and other liquids that would attack metallic materials. Secure adhesive connections are possible with plastic pipes made of PVC , CPVC and ABS . Since the turn of the millennium, applications within building technology have predominantly been replaced by press and sliding sleeve systems.

Groove connections

Connection of grooved pipe ends and similar connecting pieces via suitable couplings (e.g. Victaulic ).

Detachability of the connections

Non-detachable connection types

  • Threaded connections for pipes according to DIN 2440 (steel pipes, medium-weight threaded pipes), DIN 2441 (steel pipes, heavy threaded pipes), DIN 2442 (threaded pipes with quality specification; nominal pressure 1 to 100)
  • Connections according to DIN 2391 (seamless precision steel tubes with special dimensional accuracy) part 1 (dimensions) and part 2 (technical delivery conditions), DIN 2393 (welded precision steel tubes with special dimensional accuracy) part 1 (dimensions) and part 2 (technical delivery conditions), DIN 2394 (welds rolled precision steel pipes) Part 1 (dimensions) and part 2 (technical delivery conditions), DIN 2448 (seamless steel pipes; dimensions, length-related masses), DIN 2458 (welded steel pipes; dimensions, length-related masses), DIN 2470 (gas lines made of steel pipes with operating pressures up to 16 bar; requirements for the pipeline components)
  • Welded connections according to DIN 8564 Part 1 (welding in pipeline construction; pipelines made of steel, production, weld seam testing)
  • Brazed and welded connections on copper pipes according to DIN 1786 (installation pipes made of copper, seamlessly drawn), DVGW worksheet GW 2 (connection of copper pipes for gas and water installation inside buildings)
  • Welded connections made of plastic pipes according to DVGW worksheet G 472 (laying of pipes made of hard PVC with an operating pressure of up to 1 bar and of hard PE with an operating pressure of up to 4 bar for gas lines) and DVGW worksheet G 477 (production, quality assurance and testing of PVC pipes hard and HDPE for gas pipes and requirements for pipe connections and pipe parts)
  • Clamp connections with DVGW approval mark for plastic pipes.

Detachable connections

  • Connection pieces according to DIN 3387 for metal pipes (with smooth ends)
  • Screw connections according to DIN 2950 (malleable cast iron fittings), according to DIN 2991 (steel fittings with thread; pipe screw connections), according to DIN 3378 part 1 (gas meter screw connections; two-nozzle connection), according to DIN 3376 part 2 (gas meter screw connections; single-nozzle connection)
  • Seals for screw connections according to DIN 3535 (seals for gas supply) Part 1 (seals in gas fittings for house installation), part 3 (sealing materials made of elastomers for gas supply and gas pipelines; requirements and testing), part 4 (seals made from IT panels in gas fittings , Gas appliances and gas pipes), Part 5 (sealing materials made of rubber, cork and rubber, cork asbestos for gas fittings and gas appliances; safety requirements, testing), part 6 (flat gasket material based on synthetic fibers or graphite for gas fittings; gas appliances and gas lines ). Only seals according to Part 3, 4 and 6 are used for underground external lines.
  • Long thread made of steel or of malleable cast iron prefabricated components according to DIN 2981 - steel fittings with thread; Long thread (not for underground lines)
  • Flange connections according to DIN 2566 (threaded flange with neck, nominal pressure 10 and 16), DIN 2631 (welding neck flange, nominal pressure 6), DIN 2641 (loose flanges; welding neck, smooth collars, nominal pressure 6), DIN 2673 (loose flanges with welding neck; nominal pressure 10), DIN 16963 (pipe connections and pipeline parts for pressure pipelines made of high-density polyethylene ( HDPE )

See also

Individual evidence

  1. ↑ DIN EN 1092: Flanges and their connections
  2. ↑ DIN EN 10226: Pipe thread for connections that seal in the thread
  3. ↑ DIN EN ISO 228: Pipe thread for connections not sealing in the thread
  4. ↑ DIN 32676: Clamp connections for pipes made of stainless steel
  5. ↑ DIN 11851: Pipe fittings for rolling in and butt welding
  6. ↑ DIN EN 545: Pipes, fittings, accessories made of ductile cast iron and their connections for water pipes
  7. ↑ DIN EN 598: Pipes, fittings, accessories made of ductile cast iron and their connections for waste water disposal
  8. ↑ DIN EN 969: Pipes, fittings, accessories made of ductile cast iron and their connections for gas pipes
  9. ↑ a b Knut Håkansson: Lexicon of Gas Installation : (Gas installation from A - Z) , p. 284ff, Vulkan-Verlag, 1996
  10. ↑ DIN 16963 (pipe connections and pipeline parts for pressure pipelines made of high-density polyethylene ( HDPE ): Part 1 (types 1 and 2; pipe bends produced in segment construction for butt welding, dimensions), Part 2 (types 1 and 2; T produced in segment construction and by necking - Pieces for butt welding, dimensions), part 3 (type 1 and 2; pipe bends for butt welding, dimensions), part 4 (collars for heating element butt welding, flanges, seals; dimensions (draft)), part 5 (type 1 ; general quality requirements, tests), part 8 (types 1 and 2; angle made of injection molding for socket welding, dimensions), part 9 (types 1 and 2; T-pieces made of injection nozzle for socket welding, dimensions) and part 10 (types 1 and 2 , Sleeves and caps made of injection molding for socket welding, dimensions), part 11 (collars, flanges, seals for socket welding, dimensions), part 13 (types 1 and 2 - turned and pressed reducers for butt welding, dimensions), part 14 (types 1 and 2 - Injection molded reducers and nipples for sockets welding, dimensions), part 15 (pipe fittings, dimensions)