Polyethylene coated steel pipe, online production and equipment thereof

Abstract

The invention relates to a polyethylene coated steel pipe and on-line method and apparatus for preparing same. Steel pipe is employed as base material for polyethylene coated steel pipe, and the outer surface of the steel pipe is coated with jointless annular polyethylene gummed tape. Production facilities of the pipe includes steel pipe shot-blast rust cleaning machine comprised of a rotating cylinder bracket, a rotating cylinder, a feeding wheel, a support wheel, a feeding worm wheel speed reducer, a feeding direct current dynamo, a high-frequency induction heating coil, a driving worm wheel speed reducer, a driving AC motor and a electrical control cabinet, and a steel pipe outer anticorrosion coating machine comprised of a induction heating transformer, a walking frame, a swing frame, a rotating frame, a winding device, a supporting frame, a low-voltage electrical casing and a controller. In pipeline installation locale, the steel pipes are welded into pipelines after derusted by the steel pipe shot-blast rust cleaning machine, the steel pipe outer anticorrosion coating machine is nested on the pipeline and carries out helical motion, after high-frequency induction heating on the steel pipe, the spray head injects the epoxy powder on outer surface of the steel pipe, after high-frequency induction heating of the belt-winding cylinder, adhesive tape and polyethylene gummed tape pulled out from the winding device become hot tapes, by helical motion of the steel pipe outer anticorrosion coating machine along pipeline centre-line, the adhesive tape and polyethylene gummed tape are coated on the outer surface of the steel pipes.

Description

Technical field [0001] The invention relates to a polyethylene coated steel pipe and its online production method and equipment. In water conservancy, electric power, petrochemical and other enterprises, steel pipes erected in space are oxidized and rusted due to contact with air. The buried steel pipeline corrodes due to electrochemical reaction due to contact with active materials underground. This kind of rust or corrosion will shorten the life cycle of steel pipes. Therefore, before the steel pipe is installed, it is generally necessary to coat the outer surface of the steel pipe with anti-corrosion and anti-corrosion materials. technical background [0002] The piping systems of water conservancy, electric power, petrochemical companies, and the anti-corrosion coating of steel pipes with anti-corrosion and anti-corrosion materials have evolved from painting and asphalt on the outer surface of steel pipes to coating the outer surface of steel pip...

AI Technical Summary

Problems solved by technology

Due to the uneven heating of the artificial blowtorch, the bonding between the polyethylene cold tape and the steel pipe is not firm, which reduces the anti-corrosion quality of the polyethylene cold tape

[0008] The above-mentioned reasons limit the use of the extruded polyethylene hot tape coating method of the prior art to produce polyethylene coated steel pipes on-line at the field pipeline installation site

Extruded polyethylene hot-coated steel pipe production method needs to purchase medium-sized medium-frequency induction heating power supply, adhesive tape extruder, and polyethylene tape extruder, which not only increases the purchase cost of anti-corrosion equipment, but also consumes a lot of electricity, which increases anti-corrosion. Coating auxiliary costs increase the cost of steel pipe anti-corrosion coating

Since the elbow cannot be painted by mechanization, it can only be manually coated with polyethylene cold tape in the pipeline anticorrosion factory; the weld joints produced by the pipeline system can only be filled by manual coating of polyethylene cold tape at the pipeline welding site

Polyethylene-coated steel pipes have been transported many times from the pipeline anti-corrosion factory. During the transportation, the polyethylene-coated anti-corrosion layer is damaged due to collisions, and the polyethylene coating can only be manually painted on the pipeline installation site to repair the damage.

Manufacture of polyethylene coated elbows, welded joints, and wound repairs is not only slow in coating speed, but also the coating of anti-corrosion materials is not uniform, and the bonding between layers is not firm. The same material is anti-rust and anti-corrosion The ability is poor, and the use of mechanized polyethylene-coated straight pipes will cause many quality hazards in the entire pipeline system; and manual coating, anti-rust, anti-corrosion treatment The operating environment is poor, and the labor intensity of production workers is high , which is not conducive to safe production, and increases the auxiliary construction time and pipeline installation period

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