Fusão elétrica de tubos e fusão a quente: a diferença e a aplicação

Pipes are essential for industrial piping installations. PE (polyethylene) is widely used in water pipe manufacturing due to its high strength, corrosion resistance, and non-toxic properties. PE pipes are rust-resistant, making them an ideal alternative to ordinary iron water pipes.

The most common PE pipe connection methods used in pipeline installation are hot melt, electric fusion, socket joints, and flanges. Today, we’ll explore the usage of two of the most widely used connection methods: electric fusion and hot melt.

Electric fusion uses heat generated by electricity to melt the connecting pipes. The connecting material is placed between electrodes. Current is passed through a resistance wire in the pipe, generating heat. This heat raises the internal temperature of the material to its melting point, fusing the pipe and fitting together, completing the electric fusion connection.

Hot-melt connections are categorized into socket-and-spigot hot-melt and butt-melt hot-melt. Both utilize heaters to heat heating elements mounted on both ends (generally, the heating elements are designed to match the diameter of the pipe or pipe being hot-melted). Once the heating elements are heated, the pipe or pipe is brought close to the heating elements and melted. After a period of melting, the pipe or pipe is removed. The pipe or pipe is then butted together, and after cooling naturally under applied pressure, the hot-melt connection is complete.

Hot-melt socket connections are commonly used on DN63 small-diameter pipes, and the maximum diameter is generally DN110. Because external force is required to pressurize the pipes during pipe docking, the diameter of the pipes that can be connected is limited. Similarly, because external force is required during the pipe docking installation process, it is difficult to ensure the overall flatness of the pipes after connection. In addition, during the pressure test, it is easy for molten material to leak out of the hot-melt pipe fittings from the gaps in the pipes, affecting the appearance of the finished pipes. At the same time, the molten material may stick to the inside of the pipe, causing the internal diameter of the pipe to become smaller, affecting the water flow. However, due to its simple construction and a wide range of usage scenarios, it has been widely used in the installation of small-diameter pipes.

Butt fusion is primarily used for larger-diameter PE pipes. Conventional pipe diameters are typically DN75 and above. Hot-fusion pipes typically have thicker walls, making fittings virtually unnecessary. During the butt fusion process, a welding machine is used to fuse the pipes, which are mounted on a frame. After melting, the frame is pressurized, and the butt fusion is completed with natural cooling. Because the hot-fusion process must be performed on a frame, and due to various factors such as the larger size, thicker walls, and heavier weight of the pipes being melted, hot-fusion butt fusion is more complex. Preliminary cleaning and tightening of the pipes require significant time, making the entire process laborious and time-consuming. However, due to its advantages of reduced material consumption (no fittings required), secure connections, and high stability, it has also gained widespread application for joining large-diameter pipes.

Electrofusion connections are primarily used for pipes larger than DN50. Specialized equipment is required to connect these fittings. The site requires a basic power supply, and because electrofusion fittings contain internal heating wires, installation costs are relatively high. However, due to their minimal installation requirements, high connection strength, and excellent sealing properties, they are also widely used in pipeline installations with limited space and in some underground pipe repairs.

Both electric fusion and hot-melt PE pipe joining methods are currently well-established. Each method, along with its associated costs and labor, has its own advantages and disadvantages. A specific joining solution must be evaluated and implemented based on actual application. This approach can help reduce costs while ensuring project quality.