What are the common connection methods for PE pipes?

1. Hot Melt: A Process that Precisely Controls Temperature and Pressure

Hot melt welding is one of the most commonly used methods for joining PE pipes, suitable for pipes with diameters less than 160mm. The process involves using a hot melt welder to heat the pipe and fitting at the joint until they are molten. Then, they are quickly butted together and pressure is applied to fuse the two together. Before operation, the pipe must be cut flat with a dedicated pipe cutter, ensuring the cross-section is perpendicular to the axis. When using a hot melt welder, the heating temperature (generally 210°C - 230°C) and heating time (e.g., approximately 5 seconds for a 20mm diameter pipe) must be set strictly according to the pipe specifications. The pipe and fitting are simultaneously inserted into the heating mold, rotating the pipe at a constant speed during heating to ensure uniform heating. After heating is complete, the pipe and fitting are quickly removed and inserted into the socket joint, ensuring the specified insertion depth and maintaining pressure until they cool and solidify. The entire process must be completed within 20-30 seconds to ensure a high-quality connection. The construction manager of a municipal water supply project stated, "If hot-melt connection is performed properly, the joint strength can even exceed the pipe itself. We've used this method in multiple projects and have never experienced joint leakage."

2. Electric Fusion: The Perfect Combination of Intelligence and Efficiency

Electrofusion connection is suitable for applications with large pipe diameters or demanding connection requirements. It is particularly widely used in projects with stringent sealing requirements, such as gas transmission. It uses a resistance wire inside the electric fusion fitting to heat the pipe, melting the contact surfaces of the pipe and fitting. To operate, first insert the pipe into the electric fusion fitting to the marked depth, ensuring a tight fit. Then, connect the output end of the electric fusion welder to the electrode on the fitting. Set the welding voltage and time according to the pipe fitting specifications (for example, for a DN110 pipe, the welding voltage is typically 39.5V and the welding time is approximately 120 seconds). After starting the welder, the resistance wire heats the pipe, melting the inner and outer walls of the fitting. After cooling, a secure connection is formed. The electric fusion process is highly automated, less susceptible to human influence, and provides consistent weld quality. A gas company employed electric fusion connection in a gas pipeline renovation project in an older residential complex, significantly shortening the construction period while ensuring safe gas delivery and earning widespread praise from residents.

3. Flange Connection: A Stable Solution for Special Environments

Flange connections are an ideal choice for connecting PE pipes to metal pipes, valves, or other applications, or in situations requiring frequent disassembly and maintenance. First, connect the PE flange to the PE pipe using heat or electric fusion. Then, bolt the metal flange to the PE flange, inserting a rubber gasket in between to ensure a tight seal. During installation, ensure the flanges are parallel and tighten the bolts evenly to avoid uneven force and leaks. In industrial wastewater treatment projects, where piping systems require frequent maintenance, flange connections facilitate equipment maintenance and replacement, improving overall system efficiency.

Mastering the key operating techniques of these three common connection methods can effectively ensure the reliability and stability of PE pipe connections. Whether it is a small home improvement project or a large-scale construction project, choosing the right connection method and standardizing the operation can make the PE pipe perform at its best in various scenarios.