Polyethylene pipe and pipe, pipe and pipe fittings, pipe and accessories, as well as polyethylene pipe and metal pipe between the way there are many, different connection methods have their own advantages and limitations, users can be based on pipe diameter, working pressure, use of places and other environments, choose the appropriate connection mode. However, it is strictly forbidden to make pipe threads directly in polyethylene pipe and pipe fittings in any form, using threaded connection; it is strictly forbidden to use open fire baking polyethylene pipe, pipe fittings, direct connection.
The most commonly used connection modes of urban water supply polyethylene pipeline are: hot-melt connection, fused connection, socket flexible connection, flange connection, steel-plastic transition joint connection, etc. 1 Hot-melt connection hot-melt connection is the use of special heating tools, under pressure heating polyethylene pipe or pipe fittings to the connecting part, so that it melts, remove the heating tool, pressure to connect two molten surfaces together, under stable pressure to maintain for a period of time, until the joint cooling.
The hot-melt connection includes a hot-melt docking connection, a hot-melt socket connection, and a hot-melt saddle connection. 2 Electric Melt Connection Electric Melt connection is the use of embedded resistance wire special fused pipe fittings and pipe or pipe fittings in close contact with the power, through the buried resistance wire heating the connection site, so that its melting into one, until the joint cooling. The fused connection can be used to connect with polyethylene tubing or socket fittings of different types and different melt flow rates.
The electric melt connection is divided into electric melt socket connection and electric melt saddle type connection. 3 Socket Flexible Connection Polyethylene pipe Socket Flexible connection is a new connection method developed by reference to the principle of socket flexible connection of cast iron pipe and polyvinyl chloride pipe (PVC U), which is to weld a reinforced polyethylene bearing at one end of polyethylene pipe.
The socket flexible connection is to insert one end of the polyethylene pipe directly into the pipe or pipe fittings of the special mouth, through the locking ring in the bearing mouth compression anti-drawing, rubber seal ring Compression seal, to achieve the purpose of connecting pipe and pipe fittings. 4 Flange Connection Flange connection is mainly used for the connection of polyethylene pipe with metal pipe or valve, flowmeter, pressure gauge and other ancillary equipment. Flange connection is mainly composed of polyethylene flange connectors, steel or aluminum back pressure sleeve flanges, steel or aluminum flange slices, gaskets or seals, bolts, nuts and so on.
Flange connection is through fastening bolts, nuts, so that the flange connectors and flanges in close contact, to achieve the purpose of connection. 5 steel-Plastic transition joints connecting steel-plastic transition joints are connected to polyethylene pipes and metal pipes using steel-plastic transition connectors that are prefabricated by cold pressure or other means. Steel-plastic transition joints have anti-pulling locking rings and seals, which usually require good sealing performance and tensile and compressive properties greater than the polyethylene piping in the system.