Plastic pipe network connected by pipe jointers made of refractory non-cross-linked poly ethylene

Abstract

A composite plastic pipeline is composed of the pipe jointer made of non-cross-linked refractory polyethylene and the composite plastic pipe consisting of internal cross-linked polyethylene layer and external layer of refractory non-cross-linked polyethylene. The plastic pipes and the pipe jointer are connected by thermal fusion or electrothermal fusion. Its advantages are high thermal strength, good electric insulation, high resistance to ageing and cracking, and low cost.

Description

Technical field: [0001] The present invention relates to a pipe network, in particular to a pipe network that can be connected by non-crosslinked high temperature resistant polyethylene (Polye thylene with Raised Temperature resistance abbreviated as PE-RT) pipe connectors connected by hot melt. Background technique: [0002] Comparing cross-linked polyethylene with non-cross-linked polyethylene, especially after it is made into plastic pipes, because polyethylene is cross-linked and transformed from linear to three-dimensional network structure, which significantly improves its performance and makes cross-linked polyethylene pipes more effective. Very excellent performance, after cross-linking polyethylene pipes, heat resistance and thermal strength, heat aging resistance, environmental stress cracking resistance, electrical insulation, barrier properties, resistance to gasoline and aromatics, creep resistance, etc. are all improved Big improvement. Polyethylene can be cro...

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Problems solved by technology

However, the price of this material is high, 2 to 3 times that of ordinary thermoplastic materials, and 1.5 to 2 times that of cross-linked polyethylene, which has caused difficulties in the wider application of pipelines made of this material

[0010] In the existing technical schemes of pipe fittings and pipes, in order to increase the strength, some reinforced metal skeletons formed by steel wire or perforated steel plates are added to the pipe wall continuum to improve the pressure bearing capacity of the pipe network system and enable higher temperature The reduction factor of the pressure bearing capacity under the pipe network is smaller than that of the pure plastic pipe network, which actually increases the allowable pressure of the pipe network. The linear expansion coefficient of the composite plastic pipe is reduced to a coefficient close to that of steel, and a good useful performance is obtained, but because of the introduction of the steel skeleton, internal stress is also introduced into the pipe wall to varying degrees, especially the resistance High-temperature composite pipes (generally using isotactic or random block polypropylene materials), make it easy for the pipe wall of the composite pipe network produced by polypropylene materials that are not very good at low temperature cracking resistance and environmental stress cracking resistance. Cracking, can not be used in low temperature environment

Use cross-linked polyethylene with better resistance to environmental stress cracking to produce composite pipe networks, but it is inconvenient to weld, especially the connecting parts of pipe fittings are not easy to weld with plastic pipes or composite pipes with thermoplastic plastic on the outer wall

In order for the pipe network to have better resistance to environmental stress cracking, especially to overcome the internal stress generated by the introduction of the metal skeleton into the pipe wall, it is necessary to have a plastic material that is more resistant to environmental stress cracking and overcomes internal stress and is not easy to crack. High-temperature polyethylene material is the most suitable material. So far, only reports on the application of pure plastic pipes and aluminum-plastic composite pipes have been seen. There have been no reports of using this material and metal skeletons with holes to make composite pipes. Report on pipe network composed of pipe fittings and pipes with high pressure bearing capacity and good heat resistance to overcome the above internal stress and environmental stress

In order to increase the pressure bearing capacity of the pipe network, we must add a metal skeleton to the pipe wall, and a new plan should be adopted to make the metal skeleton have an adhesive layer and be better combined with the plastic continuum to become a real composite material. Overcome the problems of insufficient temperature and pressure resistance and stress cracking resistance of the existing pipe network

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