Combined type electric smelting pipe

Abstract

The invention provides a combined type electric melting pipe. The combined type electric melting pipe comprises an inner pipe and a sleeve, wherein the inner pipe is made of plastic, and the sleeve isarranged in the outer middle portion of the inner pipe in a sleeving mode, an inner layer resistance wire is arranged on the inner surface of the inner pipe, an outer resistance wire is arranged on the inner surface of the sleeve or the outer surface of the inner pipe, and a gap is formed between the inner pipe and the sleeve to allow the inner tube to inflate in the radial direction when the inner layer resistance wire works. When the pipe is used, the inner pipe is welded with a pipe material, the inner pipe generates certain radial deformation when the inner pipe is heated, pressure of themolten plastic is reduced through the gap allowing inflating, and axial flow of the molten plastic is reduced.

Description

technical field [0001] The invention relates to the field of pipelines, in particular to a combined electric fusion pipe fitting. Background technique [0002] In recent years, plastic pipes have been used more and more in the fields of gas, water supply and drainage. With the development of pipeline technology, the requirements for the pressure resistance of pipelines are getting higher and higher. At the same time, higher requirements are put forward for the connecting pipe fittings between pipelines. It is hoped that the connections will have good sealing performance and greater pressure resistance. [0003] Due to its excellent heat resistance, PPR material is widely used in hot water piping systems. The main feature of hot water pipes is that the wall thickness of the pipe is relatively thick. It is generally laborious to use ordinary hot-melt sockets when the diameter is large, and the construction is not easy. Convenience. Therefore, PPR electrofusion pipe fittings ...

AI Technical Summary

Problems solved by technology

[0004] After the design strength of the pipe material increases, the wall thickness of the electrofusion pipe fittings also increases. Due to the poor thermal conductivity, high welding temperature, and large melt flow index of plastics, especially PPR materials, when welding thicker pipes, the internal The temperature of the layer material is high, the expansion is fast, and the deformation of the inner layer material is restricted by the outer material. The melted plastic, especially PPR, will flow axially in the gap between the electrofusion pipe fitting and the pipe, and this flow is easy to make it spiral. If the arrangement of the resistance wires changes, once the middle part of the resistance wire is short-circuited, the heating power of the resistance wire will increase rapidly, which will intensify the melting of the plastic, and the heating power will exceed the tolerance value of the material, causing welding quality accidents such as spraying and smoking.

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