Metal-plastic clutches
In gas pipelines, heating networks, hot and cold water pipelines, couplings are used, as this allows quick repairs of the necessary sections of the network without dismantling the entire system. For structures of any material, compounds of this type can be used. They ensure a reliable connection of the pipe on both sides.
In metal-plastic pipelines, couplings are very rarely used. This is due to the fact that they are produced in the form of bays, the length of the pipes in which is up to 200 m. Therefore, during installation, the required length of material is simply cut off, but if it is necessary to use parts for connecting the ends, press clutches and threaded fittings are used for this purpose.
Threaded couplings
In order to connect the edges of pipelines with a threaded coupling, it is first necessary to prepare the edges of the pipelines - they are cut perpendicular to the axis of the pipe to ensure a tight abutment of the end of the pipe and fitting. Then disassemble the fitting itself, put on the compression nuts and o-rings on the pipes.
The first pipe is put on the union, the connection is crimped with a nut. The second is mounted in the second choke and is also crimped. The part itself is fixed with a swivel wrench and is subsequently tightened by means of a spanner wrench, both crimping nuts.
Press couplings
The installation process for press couplings is much easier and faster than threaded ones. To do this, cut the edges of the pipelines along the normal to the axis, insert them into the fittings of the fitting and press it with a special tool. Such a coupling for connecting pipes is advantageous in that it is suitable for pipes of any diameter corresponding to the assortment.
Couplings made of polymers
Polymer fittings are more common than metal plastic ones, as a lot of plastic pipelines are produced in the form of segments, less than 12 m.length.
Polymer mounts are connected:
- To socket
- On
- adhesive With diffusion welding
- On threaded connection
The socket connections are used for non-pressure pipes. This connection is sealed and reliable due to the rubber seal, but this kind of insulation is unstable to large hydraulic loads. Accordingly, the socket is used for the installation of sewerage and drainage.
As in the previous cases, the pipe edges are cut at a right angle, the sealing rings are first installed, then the first pipe is inserted into the fitting and the second pipe is inserted as far as the stop.
Glued and welded joints are also used, in most cases for installation of water supply and heating pipelines. Adhesive bonding is carried out by applying an adhesive on the outer surface of the pipeline and the inner surface of the fitting with the previous stripping. Then it is fixed for 15-20 seconds.
If it is necessary to speed up the installation time, diffusion welding can be used. The uniqueness of this connection is its very design: inside it there is a layer of special material, which easily melts under the influence of an electric current. The process of installation itself is similar to the bell-type installation, but instead of the fitting itself, the main role is played by an electrode that melts the spiral inside the part. Thus, the joint is sealed and strengthened simultaneously. The possibility of exploitation comes after full hardening of the joints.
Another fitting suitable for polymers is a compression coupling for connecting pipes. Such assemblies are formed due to compression of the pipe in the coupling by a compression ring. A distinctive feature of the installation for this type of fittings is that it does not require any special devices.
Fittings used in metal pipelines
Couplings as fittings are used for metal piping much more often than in systems made from other materials. This is due to the fact that such pipelines are produced purely as short length segments. Most often, threaded fittings are used, since with their help it is possible to dismantle a single section without disturbing the configuration of the entire network.
The fitting used in pipelines of any material and purpose is precisely a coupling for connecting pipes. Their installation is simpler and cheaper than, for example, welding, which makes them an unusually valuable detail necessary for the design and operation of the network.