Method for manufacturing anti-negative pressure plastic-lined steel pipeline

Abstract

The invention discloses a method for manufacturing an anti-negative pressure plastic-lined steel pipeline. Tapered anti-stripping holes are drilled in a steel base body in a uniform distribution mode; when a fusible plastic is melt and then is roller-coated on the inner wall of the steel base body, the anti-stripping holes also are injected with the melt plastic, and anti-stripping columns and a plastic-lined coating layer are fused into a whole; the anti-stripping columns play roles in fixing and strengthening the plastic-lined layer, thermal deformation and tensile deformation of a unit cross-sectional area are shortened, and thus the anti-negative pressure ability of the plastic-lined layer is improved. For preventing the cases that the melt plastic slurry is thrown out of the anti-stripping holes by a centrifugal force, so that dense anti-stripping columns cannot be formed and the tensile strength is affected, a special fixture is quickly mounted on the exterior of the heated and discharged steel base body.

Description

Technical field [0001] The patent belongs to the field of anti-corrosion pipeline manufacturing, and particularly relates to a method for manufacturing a negative pressure resistant steel-lined plastic pipeline. Background technique [0002] Steel-lined plastic pipes are referred to as steel substrates in the industry with steel pipes as substrates. The pipes are coated with fusible plastics with excellent chemical stability to form anti-corrosion layers, which are referred to as plastic-lined layers. Compressive strength and the corrosion resistance of plastics. However, because the plastic lining layer of the steel-lined plastic pipe is melted and roll-coated, the bonding strength between the plastic lining layer and the steel matrix is ​​not high, even due to steel The difference in thermal deformation coefficient between the substrate and the plastic lining layer causes local delamination. When encountering the negative pressure generated in the pipeline, the plastic lining l...

AI Technical Summary

Problems solved by technology

[0002] The steel-lined plastic pipeline is referred to as the steel matrix in the industry with the steel pipe as the matrix, and the meltable plastic with excellent chemical stability is coated inside the pipe to form an anti-corrosion layer, which is called the plastic-lined layer for short, so that the steel-lined plastic pipeline has the support strength and resistance of the steel pipe. However, since the plastic lining layer of steel-lined plastic pipes is melted by meltable plastic and then rolled, the bonding strength between the plastic lining layer and the steel matrix is ​​not high, and it may even be damaged by the steel. The difference in thermal deformation coefficient between the substrate and the plastic lining layer causes local delamination. When encountering the negative pressure generated in the pipeline, the plastic lining layer is easily absorbed and peeled off from the steel substrate, deformed and affects the medium transportation, and may even be caused by the deformation of the plastic lining layer. Cracking, corrosive medium directly corrodes the steel substrate, resulting in leakage accidents

The plastic-lined layer is sucked off, deformed or even broken, and it is difficult to monitor, which brings hidden dangers to the safe application of steel-plastic-lined pipelines and directly affects the expansion of the application field of steel-plastic-lined pipelines.

[0003] Among similar products, the existing technology is to weld the supporting steel mesh in the steel matrix of large-diameter pipes. The prerequisite for implementing this technology is that there must be a welding operation space in the pipe, which cannot be implemented for small-diameter long-section pipes without welding operation space. technology

Moreover, in addition to negative pressure pipelines, small diameter long pipelines and small diameter high drop pipelines in positive pressure pipelines are more likely to generate negative pressure

This is also the main reason why steel-lined plastic pipes are difficult to apply in large quantities

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