HDPE fittings are low-pressure polyethylene fittings designed for the installation of pipelines from this material. Presented with a complete range of products for piping with connecting equipment and network elements at different angles. Provide tightness of joints and ease of installation. They are used for joining pipes of the same type, as well as when installing systems made of different materials (transition from cast iron to HDPE, etc.)
Types of HDPE fittings
Fittings for HDPE pipes are represented by a wide range of products, including products of different diameters and types. The main classification includes:
Compression or crimp is the simplest type of fittings. They are intended for the installation of pipelines of small diameters and are mainly used for the laying of internal networks. Allowed only for water supply, they cannot be used for the installation of heating systems. The maximum diameter is 110 mm. Installation is carried out without the use of heating and other equipment, fixation occurs by tightening the nut. The resulting connections are detachable, can be dismantled without loss of quality and the need to shorten the pipe. This improves usability and lowers operating costs by reusing the elements.
Electrofusion fittings for HDPE pipes are used in electrofusion (electrodiffusion) welding. A heating element is installed in the inner part of the fitting, which, when exposed to current, straightens the joints of the fitting and the pipe, which, after cooling, makes it possible to obtain a high-quality connection equal to the characteristics of a cast pipe. The connection is one-piece, in contrast to the crimp with the use of compression fittings, which creates difficulties when dismantling is necessary. The section has to be cut and then welded again using adapters and pipe cuts. However, it is this method that is permissible for the installation of loaded systems operating under pressure and with elevated temperatures. Under any load, the connection point remains solid, excluding leaks and accidents.
Molded HDPE fittings Malaysia are made by injection molding and are suitable for the installation of gas supply systems and water pressure pipelines. Their installation is carried out by the method of butt welding with heating of the ends of the shaped part and the pipe and subsequent alignment of the elements. Subject to the welding technology, the resulting permanent connection is completely sealed, does not affect the throughput of the pipes, and does not differ in characteristics from the entire system.
Separately, it should be noted segment or welded fittings for HDPE pipes. This is a type of custom fittings made in the factory by butt-welding pipe parts to achieve the required bend. They are in demand for pipes of large diameters, especially those that are not produced in-line. They are used for the installation of sewer pressure networks in the places of turns, branches, connections to existing highways. To ensure stability and prevent accidents after installation, the segment fitting should be monolithic with reinforced concrete supports, the layout of which should take into account the linear expansion of the polyethylene under the influence of temperature. Suitable for water only. For gas, a different installation method is used.
Characteristics and features of HDPE fittings
The characteristics possessed by PND fittings are predetermined by the material of manufacture. Being an ethylene polymer, polyethylene has a stable crystal lattice, which under normal conditions is not exposed to any influences other than temperature and UV radiation. High temperatures lead to deformation of the wall, causing its expansion and contraction, which, when laying the pipeline without a channel, especially in the case of systems with a large diameter, can lead to bending and blocking of the lumen. The same applies to laying in unstable soils and explains the need to use trays. Ultraviolet light, in turn, dries up the wall, causing an increase in fragility. This applies to all piping elements, including fittings. Therefore, manufacturers recommend observing storage conditions, especially if the installation is carried out in several stages.