Metal plastic composite tube with thermoplastic tube end contact flange

Abstract

The invention provides a metal plastic composite tube with a thermoplastic tube end contact flange. A cylindrical metal tube wall which can bear fluid pressure and does not have a hole and a composite tube wall which is at least compounded with the inner wall of the metal tube wall and is formed by at least one plastic layer are arranged in the metal plastic composite tube, wherein the composite tube wall on the end part of the metal plastic composite tube is provided with a plurality of holes; the holes are filled with thermoplastic plastics of the plastic layer of the tube wall with hot melt connecting performance; and the thermoplastic plastics cover the cylindrical metal tube wall through the holes and are in hot melt connection with at least one plastic layer compounded with the inner wall so as to form the thermoplastic tube end contact flange which has connecting function and bears axial tensile force of a pipeline. The tube end contact flange completely and tightly covers a plastic outer layer and a plastic inner layer of a metal framework reinforced plastic composite tube tip, a pipeline end surface and the cylindrical metal tube wall through the holes, firm and reliable in connection, non leakage and high mechanical strength of the connecting position, prevents the fluid from corroding the metal framework, and has long service life.

Description

Technical field: [0001] The invention relates to a metal-plastic composite pipe with a thermoplastic pipe end connecting flange. Background technique: [0002] A large number of technologies and pipes of metal and plastic composite pipes have been applied in engineering. A layer of plastic is compounded on the inner wall and / or outer wall of the metal pipe. A large number of pipes have been used. This structural pipe is different from pure metal pipes. Compared with the pure metal pipe, it retains the strength of the pure metal pipe, and increases the anti-corrosion and thermal insulation performance. Compared with the pure plastic pipe, it increases the application performance of aerial erection, the reliability of open-air use and the strength guarantee of high-temperature use; compared with the steel skeleton with holes Compared with plastic composite pipe, it increases the reliability of high temperature use and outdoor use, as well as fire resistance and flame retardanc...

AI Technical Summary

Problems solved by technology

However, since the linear expansion coefficient of the composite plastic layer and the metal pipe wall differs by an order of magnitude, the composite plastic layer and the metal pipe wall will have different thermal expansion and cold contraction length changes when used in projects with large changes in cold and hot environments. There will be a length difference between the plastic layer and the metal pipe wall. At the pipe end, the metal pipe wall will be exposed due to the shrinkage of the plastic layer, and the fluid medium will directly contact the metal pipe wall, resulting in corrosion of the pipe wall or corrosion at the joint flange, and finally the pipe net failure

Although we have made many technical improvements and implementation plans at the pipe end and the connection between the pipe end and the pipe fittings, it is easy to expose the metal pipe wall in the fluid medium because of the composite section of the metal pipe wall and the plastic layer at the pipe end. It is corroded, and after the plastic layer shrinks, a large amount of bare metal pipe walls are not only accelerated, but also the fluid medium is easily driven by pressure into the space between the inner wall of the metal pipe and the plastic composite layer, which makes the function of the composite pipe invalid and the anti-corrosion function disappears.

Therefore, the application of this type of composite pipe is greatly restricted, especially in projects with hot water pipe networks, strong corrosive fluid medium transportation, large changes in cold and hot fluid media, and large changes in the ambient temperature of the transport medium. The application of this type of composite pipe has become a difficult problem.

Steel skeleton plastic composite pipes include perforated steel belt plastic composite pipes, steel wire winding and welded skeleton plastic composite pipes, etc. Although the problem of linear expansion difference between the metal skeleton and the plastic composite layer is solved, they work when the heat medium is transported above 80°C The pressure discount is 40% to 40% off, and it is not easy to run for a long time above 85°C

This kind of pipe is easy to age because the plastic is not resistant to ultraviolet radiation, and it is not easy to use in the open air. It is inconvenient to use in the open air environment of general chemical industry. If the heat-resistant cross-linked polyethylene material is used, it can be used in the open air and the operating temperature can reach 90 ° C, but it makes the pipe difficult to regenerate. Hot-melt connection is inconvenient for construction and cannot be used as a pipe network. Even if the pipe network is connected to form a pipe network before cross-linking and then hydrolyzed, condensed and cross-linked, it is inconvenient to re-melt the connection and repair after the pipe network fails.

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