Protecting coating for outer side of metallic pipe

FIELD: construction.

SUBSTANCE: protecting coating comprises several layers. One of the layers is made of an elastomer. The elastomeric sealing layer is made of a calendered raw rubber which is protected with the fiber glass fabric from both sides. The fiber glass fabric is impregnated with phenol-formaldehyde resin with subsequent solidifying and vulcanizing the rubber.

EFFECT: enhanced reliability.

1ex

 

The invention relates to the protection of metallic pipelines, in particular, intended for placement in the soil at the bottom of the sea, from corrosion and other destructive influences of the environment, more specifically to a protective coating for the outer surface of the metal pipe.

Metal pipelines to transport oil, gas, water and other environments are laid out in the land and in aquatic environments, including the seabed. Therefore, corrosion protection outer surface of metal pipes and today is the actual problem.

For protection against corrosion of the outer surface of metal pipes use a variety of polymeric materials: paints, bitumen sealants, and others.

They all have one common drawback: cracks, gaps, i.e. violation of corrosion protection of pipelines, formed in the process of transporting, laying, welding and pipeline operations.

From the patent literature known a number of technical solutions containing, for example, a layer of woven fabrics of glass fibre, of a sealing layer of elastomeric material on the basis of filled silicone elastomer (U.S. Pat. RF 2136504, IPC 7 32 In 7/02, publ. 10.09.1999, from the application of the RF 95115772, IPC 7 09 D 109/06 from 27.12.1996) known coating to protect pipes from underground corrosion by applying a soil layer based on bitumen and rubber and protective the layer of extruded polyethylene. Before applying this coverage provide preheating of the pipe to 50-80°and optionally between the soil and the protective layer is applied intermediate layer, the composition of which is butadienestyrene rubber.

From EP 132219, IPC 7 F 16 L 58/10, 23.01.1985, known coating on pipe corrosion-resistant plastic layer with a thickness of 1 mm, This layer consists of glass fiber, filler and a hardening polyester resin. After applying the layer hardens.

From patent GB 2245046, F 16 L 58/10, 29 45/00, 18.12.1991, known cladding coating for pipes, which is carried out by wrapping the mandrel with a thin sheet of rubber with subsequent full or partial vulcanization. Know the use of woven or woven shirts for coating pipes, on which is applied a coating of synthetic resin (FR 2259570, F 16 L 58/10, 16.08.1985).

The closest analogue of the claimed invention is a protective coating for the outer surface of the metal pipe by U.S. Pat. RF 2127396, IPC 7 F 16 L 58/10, 10.03.1999, including impact-resistant outer layer and sensitive to the effects of pressure adhesive inner layer deposited on the outer layer, and a layer containing at least one enhancing the adhesion of the substance deposited on the free surface of the inner layer. Sensitive to pressure the inner layer is based is and any suitable elastomer, i.e. materials with properties similar to rubber. Such materials are, for example, natural rubber, colloquoy, a copolymer of styrene and butadiene, silicone rubber, regenerated rubber, etc. etc. Mentioned layer of elastomer has a thickness of 8-30 μm.

The disadvantages of the above solutions and prototype are the following:

- use as protective coatings of bitumen, polyester and other resins and thermoplastics allows you to apply a protective coating immediately before laying pipe. This complicates and increases the cost and is not possible with high reliability to protect the outer surface of the pipe, since the deposition process is carried out in the field. In the case of the application of these protective coatings in stationary conditions is a violation of surface protection during storage and transport tubes;

- use as high impact polyethylene material with drawing him additives to increase the adhesion of it to hermetico complicates the process of protection of metal piping and does not guarantee high-quality coverage due to the occurrence of microcracks in the difference of the linear expansion coefficients of materials and protection of the pipeline;

- due to the low thermal stability and Flammability protection requires 100-200 mm, leaves from both ends of pipe free from defenses is to perform welding;

when shock loads during storage, transportation, installation and operation of the defense sees the load as a whole, which can lead to cracks in the defense.

The objective of the invention is to provide corrosion protection of metal piping with a high degree of reliability in operation at different operating conditions with simultaneous simplification of the application until the application protection by the manufacturer of the pipe, and a stacker tubes only protect a small width to 20-40 mm weld pipes.

This object is achieved in that the protective coating to the outer surface of the metal pipe, including layers, one of which is made of elastomer, according to the invention as a last used raw Karandawala rubber, protected on two sides of the deformation and welding pipe fiberglass pre-impregnated with a liquid phenol-formaldehyde resin, followed by curing and vulcanization of rubber.

The proposed protective coating helps to protect the sealing layer from external damage (shock) and internal deformation of the pipes that occur during transportation, installation and operation of pipelines. This is achieved in that the sealing layer (rubber) works independently, but not together in a the protective layer. Then the problem is solved due to the strong mechanical connection sealant with two layers - the outer and inner fiberglass, formed after curing fiberglass and phenol-formaldehyde resin. Strong mechanical bond is formed as a result of penetration of the sealant into the micropores on the surface of the fiberglass. Thus the mechanical load perceive adhesive sealant layers with fiberglass.

The proposed protective coating of pipes allows to reach higher shock loads than protection, which includes films from thermoplastic materials - polyethylene, polypropylene, polyvinyl chloride.

Manufacturer offer the protective coating of the outer surface of the piping is possible in any steady-state conditions by the manufacturer of the pipes. The shelf life of the pipes with the proposed protective coating is not limited, and storage can be carried out at a temperature of from -60 to + 60°C.

High temperature resistance (up to 250° (C) and trudnogoryuchee the claimed protective coatings can be applied on almost the entire outer surface of the pipe, leaving only the edges of a width of 10-20 mm from both ends of the pipe. And the simplicity of the coating on the welded seam of tubes at their connection and with a small surface allows you to get high-quality and uniform protection throughout the outer surface of the RUB

An example of carrying out the invention

The outer surface of the metal pipe mechanically cleaned (without solvent) from the remnants of rust and other foreign objects.

Departing 10-20 mm from the edges of the pipe reel 1-2 layers of glass fabric brand scientific-210 (TC 6-48-00202956-30-94), pre-impregnated with phenol-formaldehyde resin grade SPI-304(GOST 20907). 3 Quiroga fits sealant raw Karandawala rubber based on the best choice of rubber (THE 38-105-1082-86). In the operation of pipelines, requiring high corrosion resistance protection, use raw Karandawala rubber-based SKEPT or ftorkauchukov.

After applying the foam on it is wound 2-5 layers ( depending on the diameter metal pipes) fiberglass scientific brand-210, impregnated with phenol-formaldehyde resin grade SPI-304. 3 Quiroga is a curing resin and vulcanizing the rubber at a temperature of 140-160°C.

In a similar way to protect the weld pipes.

Protective coating for the outer surface of the metal pipe, including layers, one of which is made of elastomer, characterized in that the elastomeric sealing layer used raw Karandawala rubber, protected on both sides from deformation and welding when joining pipes with fiberglass, has preliminarily is impregnated with a liquid phenol-formaldehyde resin, followed by curing and vulcanization of rubber.



 

Same patents:

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2 cl, 9 ex

FIELD: construction.

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SUBSTANCE: device comprises the assembling-arresting unit which locks the bushing against self-unscrewing. The bushing is provided with a heat insulating material and sealing composition and is made of the self-unscrewing spring, which accumulates mechanical energy. The inner end of the spiral belt is provided with a blade, which is mounted in the vicinity of the face edge of the inner end of the belt and the ends of which are provided with guiding projections. The method comprises setting the assembling-locking unit with the bushing on the pipe end to be welded, assembling the pipe butt by moving the end of the pipe to be welded onto the projections of the bushing and heat insulating material to provide a gap between the pipe faces, unlocking the bushing, and removing the assembling-locking unit. The spiral belt is unwound with sliding with respect to the inner end. The gap size depends on the thickness of the assembling-locking unit. The projections of the blade cooperate with the side edges of the belt turns and cause the sealing composition to move thus providing a protecting roll.

EFFECT: enhanced reliability of the pipeline.

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1ex

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EFFECT: enhanced reliability.

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