RU205203U1 - Metal pipe with multilayer protective coating - Google Patents

Abstract

The utility model relates to the main pipeline transport, intended mainly for gas transportation. The technical result of the utility model is achieved due to the fact that a metal pipe with a multilayer coating contains the lower, middle and outer layers, while the lower (closest to the metal) coating layer is made made of thermoplastic polymer, the middle layer is made of fiberglass based on polyester resin, and the outer layer is made of gelcoat (polyester binder with the addition of a dye). The use of this utility model allows increasing the reliability, safety and service life of trunk pipelines due to high resistance to various external factors.

Description

The utility model relates to the main pipeline transport, designed primarily for the transportation of gas.

A trunk gas pipeline is a pipeline designed to transport gas from an area of production or production to an area of its consumption, or a pipeline that connects individual gas fields.

It is known from the prior art that metal (mainly steel) pipes are used in the construction and operation of oil and gas pipelines. To ensure reliable operation of steel pipelines for a long time, they are protected from corrosion by a multilayer polymer coating.

As external protective polymer coatings of pipes against corrosion, pipe coatings based on extruded polyethylene are most widely used. The quality of factory-made polymer coatings for pipes largely depends on the design of protective coatings and insulating materials used for their application.

There are 4 options for the design of factory-made polymer coatings for pipes:

polyethylene coating applied over the bitumen-mastic sublayer (coating design No. 6 in accordance with GOST R 51164-98);

a polyethylene coating applied over an insulating sublayer based on an adhesive polymer tape (coating design No. 7 in accordance with GOST R 51164-98);

a two-layer polymer coating consisting of an adhesive sublayer based on a hot-melt polymer composition and an outer polyethylene layer (coating design No. 2 in accordance with GOST R 51164-98, coating design No. 4 in accordance with GOST R 52568-2006);

a three-layer polymer coating consisting of an epoxy primer layer, an adhesive polymer sublayer and an outer polyethylene layer (coating design No. 1 in accordance with GOST R 51164-98, coating design No. 1-3 in accordance with GOST R 52568-2006).

Long-term protection from corrosion by polymer coating of pipes is provided only if the coating is not damaged during transportation, laying and operation of the pipeline. To prevent damage to the polymer coating of pipes during transportation and installation, it must be handled with extreme care. Despite the precautions taken, the need for repairs remains high. Mechanical protection, both of the pipeline itself from external loads, and the environment from the mechanical components of the pipeline (for example, when the metal base is destroyed under the influence of unforeseen factors) is practically absent.

Known steel pipe with a multilayer coating, the closest to the claimed utility model and taken as a prototype, containing the lower, middle and outer polymer layers. In this case, the lower layer of the polymer coating is made of an epoxy primer, the middle layer of the polymer coating is made of an adhesive modified composite based on polyolefins. Moreover, the outer layer is made with the possibility of applying a composite based on polyolefins to the middle layer by extrusion and subsequent crosslinking under the action of an electron accelerator (patent for utility model No. 164448 dated August 27, 2016).

The disadvantage of this pipe is the low reliability of the pipe due to insufficient mechanical strength of the protective coating.

The use of this utility model does not provide sufficient strength of the protective coating under external mechanical action, since the prototype patent uses a mechanical mixture of polymers with the addition of a finely dispersed filler with homogeneous properties. The resulting coating material has properties close to those of the original polymer, does not provide mechanical reinforcement of the steel pipe, there is no protection of the surrounding space when the pipe is destroyed, and is susceptible to mechanical damage.

The technical problem of the present utility model is the creation of a multilayer coating for a metal pipe, which has a high efficiency of anti-corrosion protection in the presence of high mechanical strength.

The technical result of this utility model is to increase the reliability, safety and service life of trunk pipelines due to high resistance to various external factors, incl. mechanical stress, as well as protection of the surrounding space in case of destruction of the inner metal pipe.

The specified technical result is achieved due to the fact that the metal pipe with a multilayer coating contains the lower, middle and outer layers, while the lower (closest to the metal) coating layer is made of a thermoplastic polymer, the middle layer is made of fiberglass based on polyester resin, and the outer layer - from gelcoat (polyester binder with the addition of a dye).

In a metal pipe with a multilayer polymer protective coating, the lower layer of thermoplastic polymer can be reinforced with glass cloth.

The use of a layer of thermoplastic polymer provides a hermetic protection of the pipe metal from external influences. Also, due to the relatively low modulus of elasticity, thermoplastic polymers in the pipeline structure act as a damper between the metal and fiberglass and ensure their strong bond.

A fiberglass layer based on fiber filler provides:

protection of the sealing (damper) layer from external influences during transportation, storage and installation of the pipe.

increases the safety margin of a metal pipe by at least 20%;

a significant increase in fracture toughness, which protects the surrounding space when the inner metal pipe is destroyed (withstands the operating pressure of the pipeline and prevents the scattering of metal fragments);

ensures the operability of the gas pipeline in the event of damage to the metal pipe (gradual pressure drop), which avoids the consequences of an accident of the prototype structure.

The outer layer of gelcoat is an indispensable element of fiberglass, which works under atmospheric influences, it provides moisture resistance and protection from ultraviolet radiation, significantly extending the service life of the pipeline.

The essence of the utility model is illustrated by a drawing. FIG. 1 shows a pipe with a multilayer protective coating, where 1 is a metal pipe, 2 is a layer of thermoplastic polymer, 3 is fiberglass, 4 is a gelcoat.

The manufacture of a pipe with a multilayer protective coating is carried out in the following sequence:

Example 1

1) A new metal pipe or a used metal pipe is used as the original pipe (item 1, Fig. 1).

If a new metal pipe is taken for the original pipe 1, the protective grease is removed first. If a used metal pipe is taken for the original pipe 1, but meets the permissible chemical and physical criteria of deterioration, it is subjected to routine maintenance, while the products of corrosion, hydrocarbon deposits are removed from the inner surface of the original metal pipe along its entire length by known methods. A mandatory stage in the preparation of a metal pipe is shot blasting.

2) A damper layer made of a thermoplastic polymer (for example, Sevilen - position 2, Fig. 1) is applied to the surface of a metal pipe by winding a tape from it and further heat treatment of the pipe (for example, using IR lamps). It is allowed to apply a damper layer by spraying a polymer melt, without the need for further heat treatment.

3) The surface of the damper layer is degreased with gasoline, and a fiberglass layer is applied (position 3, Fig. 1) by wet winding of glass rod impregnated with a polyester binder (for example, T30 roving made of Advantex glass TU 5952-084-05763895-2017, impregnated with a resin-based binder Kamfest 0103 TU 20.16.40-006-48427630-2017).

4) A decorative protective coating (for example, polyester gelcoat TU 2257-004-48427630-09 - position 4, Fig. 1) is applied to the surface of uncured fiberglass from glass yarn by spraying.

5) Multilayer metal-polymer pipe is heat-treated at a temperature of 80 ° C. Curing under the influence of IR lamps is possible.

Example 2

The technology for manufacturing a metal pipe with a multilayer polymeric protective coating according to example 1, in which, in addition, a fiberglass cloth impregnated with a material of a damping layer (item 5, Fig. 2) is wound on the lower damper layer of a thermoplastic binder (after it is applied to a metal pipe) to increase adhesion at the border of the damper layer - fiberglass.

The use of the utility model makes it possible to increase the reliability, safety and service life of trunk pipelines.

Claims (2)

1. Metal pipe with a multilayer protective coating containing the lower, middle and outer layers, while the lower coating layer is made of thermoplastic polymer, the middle layer is made of fiberglass based on polyester resin, and the outer layer is made of gelcoat. 2. A metal pipe with a multilayer protective coating according to claim 1, characterized in that the lower layer of thermoplastic polymer is reinforced with fiberglass.

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