The connection methods of polyethylene pipe mainly include hot melt connection, electric fusion connection, socket flexible connection, flange connection, and steel-plastic transition joint connection. This article mainly introduces How to connect poly pipes. and connection precautions.
How to connect poly pipe?
Hot melt connection
A hot melt connection is when a special heating tool is used to heat the connection part of the polyethylene pipe or pipe fitting under pressure, melt it, remove the heating tool, and pressurize the two molten surfaces together until the joint cools down. Hot melt connection includes hot melt butt connection, hot melt socket connection, and hot melt saddle connection.
How to connect poly pipe? – Electric fusion connection
An electric fusion connection uses a special electric fusion pipe fitting with embedded resistance wire to contact the connection part of the pipe or pipe fitting closely and energize it. The embedded resistance wire heats the connection part to melt it into one until the joint cools down. Electric fusion connection is divided into electric fusion socket connection and electric fusion saddle connection.
Socket-and-spigot flexible connection
The socket-and-spigot flexible connection is to weld a reinforced polyethylene socket on one end of the polyethylene pipe, and directly insert the other end into the special socket. The locking ring in the socket is pressed to resist pulling, and the rubber sealing ring is pressed to seal, so as to achieve the purpose of connecting pipes and fittings.
Flange connection
Flange connection is mainly used for the connection between polyethylene pipes and metal pipes or valves, flow meters, pressure gauges, and other ancillary equipment. It consists of polyethylene flange connectors, steel or aluminum back pressure slip-on flanges, steel or aluminum flanges, gaskets or sealing rings, bolts, nuts, etc. The flange connectors are closely connected with the flanges by tightening the bolts and nuts to achieve the connection purpose.
Steel-plastic transition joint connection
Steel-plastic transition joint connection is to connect polyethylene pipes and metal pipes using steel-plastic transition joints prefabricated by cold pressing or other methods. The steel-plastic transition joint has a pull-out locking ring and a seal ring, which are usually required to have good sealing performance and pull-out resistance and pressure resistance greater than the polyethylene pipes in the system.
These methods have their own characteristics. The choice of connection method depends on the specific construction conditions, the use environment, and the requirements of the pipeline. For example, the advantages of HDPE Electrofusion Fittings are reliable quality and high construction efficiency, but the cost is relatively high; while HDPE Fusion Fitting is widely used because of its relatively simple process and equipment.
Precautions for polyethylene pipe connection
1. Before connecting the pipeline, the appearance of the pipes and fittings should be inspected to ensure that their pressure resistance level, outer surface quality, matching quality, etc. meet the design requirements.
2. Special heating tools should be used for heating, and open-flame heating should be avoided.
3. For pipes connected by welding, it is recommended to use pipes and fittings of the same grade of material or to use pipes and fittings with similar performance after passing the test.
4. When connecting in cold climates or windy environments, protective measures should be taken or the connection process should be adjusted.
5. After the pipeline is connected, an appearance inspection should be carried out, and those that fail to meet the requirements should be reworked immediately.
