a mouth filling method

Abstract

The invention discloses a joint coating method. The method comprises the steps that: firstly, surface treatment is carried out; secondly, preheating is carried out on a steel pipe; thirdly, the surface is coated with a joint coating piece; fourthly, the joint coating piece is coated with a metal interior lining panel; fifthly, coating and tightly locking are carried out on a steel hoop and an electric heating device; sixthly, warming is carried out by a program; seventhly, equipment is disassembled. The metal interior lining panel is high in rust-proof capacity, and is tightly connected with the joint coating piece as a whole in an adhesive mode, so that the barrier property to visible light, ultraviolet light, water, oxygen, and vapour of a joint coating layer is greatly improved, the mechanical damage resistance to a pointed object is enhanced, and the service life of the joint coating layer is greatly prolonged. By means of the steel hoop to carry out tightly locking and pressuring, enormous pressure is exerted on the joint coating piece during the softening and bonding process, the bonding strength on the steel pipe is greatly improved, the peeling strength under 23 DEG C can reach above 250 N / cm, the peeling strength under 50 DEG C can reach above 100 N / cm, and the peeling strength under 23 DEG C and the peeling strength under 50 DEG C are twice and five times stronger than the heat shrinking sleeve (belt) joint coating respectively.

Description

technical field [0001] The invention belongs to the technical field of construction of gas transmission and oil pipelines, and in particular relates to a joint filling method. Background technique [0002] The steel pipelines used in the construction of oil and gas pipelines must undergo anti-corrosion treatment in advance. 3LPE and 3LPP anti-corrosion layers are commonly used anti-corrosion structures for external anti-corrosion of pipelines. During the pipeline anticorrosion process, welding joints are often reserved, generally with a width of 100-150mm. The butt steel pipes are welded to each other at the reserved welding joints, and the prefabricated anti-corrosion layers at both ends are wrapped on the butt steel pipes. The anticorrosion of welded joints of steel pipelines is completed at the construction site, and the pipeline filling technology used has a significant impact on the overall anticorrosion effect of the pipeline, because it is related to the final anticor...

AI Technical Summary

Problems solved by technology

[0004] 1. The heat-shrinkable sleeve (belt) is generally baked by a manual hand-held grill with a flame, and the temperature accuracy and uniformity are difficult to accurately control

Low temperature can not guarantee the bonding effect, local overheating will easily cause carbonization of the heat shrinkable sleeve (tape), uneven heating will cause air bubbles and wrinkles due to uneven shrinkage, and the quality of the joint is difficult to guarantee

[0005] 2. The hot-melt adhesive used in the heat-shrinkable sleeve (belt) has strong polarity and low molecular weight, and is not compatible with PE or PP on the surface of the anti-corrosion layer of the straight pipe. In addition, the elastic shrinkage force of the cross-linked polyethylene substrate is not large when heated , the pressure applied to the hot melt adhesive is limited, the hot melt adhesive and the straight pipe anti-corrosion layer cannot form a reliable bond, and debonding and cracking are prone to occur after burial, resulting in failure of the joint

[0006] 3. Radiation cross-linked polyethylene heat-shrinkable tape (sleeve) must be produced through multiple processes such as extrusion molding, radiation cross-linking, diameter expansion, cooling, and glue coating. cause some damage

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