RU2729581C1 - Method of local repair of operating pipeline - Google Patents

Abstract

FIELD: pipelines.SUBSTANCE: invention relates to pipelines of networks of engineering and technical support and main pipelines of oil and oil products. Method of local repair of operating pipeline includes technology of preparation of defective section of pipeline to installation on it of repair structure from insert with pad, ties, upper and lower halves of repair case, installation of insert in pre-made process hole and its fixation, installation of reinforcing mesh and lower half of repair case using sling connected to traverse, filling of previously prepared cement-sand mortar space between lower half of repair case and pipeline, with application of cement-sand solution on pipeline surface in place of subsequent installation of upper half of repair case, rigid connection to each other on welding of upper and lower halves of repair case, holding defective section of pipeline until final solidification of cement-sand mortar and bringing pipeline ready for pumping.EFFECT: invention can be used in repair works in places of local damages.1 cl, 6 dwg

Description

The invention relates to the field of pipelines of utility networks and main pipelines of oil and oil products and can be used when performing work on their repair in places of local damage.

As practice shows, the most frequent causes of emergencies on pipelines are local damage caused by corrosion, cracks in welded joints and external mechanical influences. At the same time, the most common way to eliminate such damage is to replace defective sections of pipelines, which requires the use of labor-intensive technologies and a lot of time for the preparation and production of repair work.

When reviewing the technical literature, a number of technical solutions related to the specified problems were identified.

A known method of repairing a pipeline (options), consisting in the fact that the winding on the pipeline of several layers of an elastic-flexible tape spiral with a phased layer-by-layer gluing of the spiral turns, followed by layer-by-layer compression of the turns on the pipeline and additional heating to obtain a band, winding a tape spiral with certain speeds movements of the woven filler, tension and heating temperature of the bonding material made of epoxy resin and phenolic-formaldehyde varnish, curing the workpiece or introducing a heat-shrinkable filler between the tape layers or on one of its surfaces followed by its removal, introducing non-impregnated (dry) filler layers to increase the memory effect tape form (patent for invention RU 2156397, class F16L 55/17, F16L 58/16, publ. 09/20/2000, bull. No. 26).

The disadvantages of this method are:

the difficulty of achieving uniformity of the repair structure on the pipe body and the associated difficulty of ensuring its tightness, especially when it is installed on pipelines with high pressure of the pumped medium;

the need to use special mechanisms and equipment to perform work on winding a tape spiral with specified modes of its tension and heating, which complicates the use of this method in conditions of low ambient temperatures;

the inability to provide a flat surface in the inner cavity of the pipe in the place of the defect being repaired, which leads to an increase in local resistances during the movement of the pumped medium in the pipeline in its defective section and deterioration of the hydraulic pumping modes.

A device and a method for repairing a pipeline are known, including the manufacture of a device from a flexible sheet material containing two layers of a composite-impregnated hybrid fabric made of carbon and kevlar threads with a polyethylene layer applied to it on one side and a layer of an epoxy resin-based compound on the other hand, loops and tensioners , holding the device in the open air for the time required to impregnate the layers of the hybrid fabric and partially cure the compound, install the device on the pipe section to be repaired, firmly press the side with the compound against the pipe, fix the device with a bolted joint and tension (patent for invention RU 2525103, class F16L 55/175, F16L 55/172, F16L 55/18, publ. 08/10/2014, bul. No. 22).

The disadvantages of this technical solution are:

complexity of application in conditions of low ambient temperatures;

the inability to provide a flat surface in the inner cavity of the pipe in the place of the defect being repaired, which leads to an increase in local resistances during the movement of the pumped medium in the pipeline in its defective section and deterioration of the hydraulic pumping modes.

The closest to the claimed invention is a system and method for repairing pipes, consisting in the imposition of a fibrous structure on the section of the pipe to be strengthened, installing a seal and an external retaining component on the pipe, consisting of two halves connected by clamps through sealing elements, injecting resin of a certain viscosity and surface tension through the fibrous structure to the pipe section through a filler pipe attached to the holding element for impregnating the fibrous structure with resin, resin curing (patent for invention RU 2277201, class F17D 3/03, publ. 05/27/2006, bull. No. 15 ).

The disadvantages of this technical solution are:

the complexity of ensuring the required tightness and durability of the repair structure when it is installed on pipelines with high pressure of the pumped medium;

the inability to provide a flat surface in the inner cavity of the pipe in the place of the defect being repaired, which leads to an increase in local resistances during the movement of the pumped medium in the pipeline in its defective section and deterioration of the hydraulic pumping modes.

The problem to be solved in the invention is to eliminate these disadvantages by applying a method that ensures the tightness and durability of the repair structure, including on pipelines with a high pressure of the pumped medium, and reducing local resistances in defective sections of pipelines.

The technical result of the invention is to improve the efficiency and reliability of the local repair of the existing pipeline.

The task is being solved, and the technical result is achieved as a result of the fact that the method of local repair of an existing pipeline is that:

- at the first stage of pipeline repair, pumping through the pipeline is stopped, at the place of the repaired defect, insulation is removed, its edges are leveled, a rectangular technological hole is formed, the outer surface of the pipeline is cleaned from corrosion along the perimeter of the technological hole, an insert is prepared according to the size of the technological hole and rigidly connected to lining, prepare the upper and lower halves of the repair case;

- at the second stage of pipeline repair, an insert is installed in the technological hole, a patch is connected to the adhesive composition with the outer surface of the pipeline cleaned from corrosion and the patch is pressed against the pipeline with two ties installed along its vertical edges;

- at the third stage of pipeline repair, a reinforcing mesh is installed around the circumference of the defective section of the pipeline, the lower half of the repair case is brought under the lower part of the defective section of the pipeline and suspended on slings attached to the traverse;

- at the fourth stage of pipeline repair, the space between the lower half of the repair case and the pipeline is filled with a previously prepared cement-sand mortar, a cement-sand mortar is applied to the surface of the pipeline in the place of subsequent installation of the upper half of the repair case;

- at the fifth stage of pipeline repair, the upper half of the repair case is lowered, it is rigidly welded to the lower half of the repair case, the slings are removed, the defective section of the pipeline is maintained until the final hardening of the cement-sand mortar and the pipeline is ready for pumping.

The invention is illustrated in FIG. 1-6.

FIG. 1 shows a schematic diagram of the stage of sealing a defect in a pipeline, side view.

FIG. 2 shows a schematic diagram of the stage of sealing a defect in a pipeline, an end section view.

FIG. 3 shows a schematic diagram of the movable connection of the lower and upper halves of the repair case, side view.

FIG. 4 shows a schematic diagram of the stage of installation of the repair case, sectional view.

FIG. 5 shows a schematic diagram of the stage of rigid connection between the lower and upper halves of the repair case, sectional view.

FIG. 6 shows a schematic diagram of the stage of rigid connection between the lower and upper halves of the repair case, side view.

FIG. 1-6, the following designations are used:

1 - pipeline;

2 - a defect being repaired;

3 - technological hole;

4 - pad;

5 - screed;

6 - insert;

7 - upper half of the repair case;

8 - lower half of the repair case;

9 - loop;

10 - reinforcing mesh;

11 - sling;

12 - traverse;

13 - cement-sand mortar.

The method of local repair of an existing pipeline is implemented as follows.

Determine the location of the defective section of pipeline 1 and stop pumping. In the case of underground execution of pipeline 1, a pit is torn off and the surface of the defective section of pipeline 1 is cleaned to a width sufficient to install the upper 7 and lower 8 halves of the repair case. In the area of the repaired defect 2, the insulation is removed from the outer surface of the pipeline 1 and its edges are leveled, forming a rectangular technological hole 3. The outer surface of the pipeline 1 is cleaned from corrosion along the perimeter of the technological hole 3 to a width of about 100 mm from each of its edges. According to the size of the technological hole 3, the inner radius and the thickness of the pipe wall (excluding its insulating coating) in this section of the pipeline 1, a workpiece is selected from the repair fund and an insert 6 is cut out of it. By the size of the cleaned surface around the technological hole 3 and the outer radius of the pipe (without taking into account its insulating coating) in this section of the pipeline 1, a pad 4 is prepared. Insert 6 and pad 4 are rigidly connected to each other by welding. Prepare from the repair fund the upper 7 and lower 8 halves of the repair case with radii at least 100 mm higher than the radius of the outer surface of the pipe (taking into account its insulating coating) in this section of pipeline 1, and the width at which their edges should be at a distance not less than 1000 mm from the vertical edges of the technological hole 3. The vertical edges of the upper 7 and lower 8 halves of the repair case are made with sides with a height approximately equal to the difference between the inner radius of each of them and the outer radius of the pipe (taking into account its insulating coating) in this section of the pipeline 1 The upper 7 and lower 8 halves of the repair case on one of the adjacent sides are movably connected to each other on hinges 9.

An adhesive composition of polymeric materials resistant to the effects of the medium pumped through the pipeline, as well as to temperature and vibration influences is applied to the outer surface of the pipeline 1 that is cleaned from corrosion, and insert 6 is installed in the technological hole 3, ensuring tight pressing of the cover 4 to the external cleaned from corrosion the surface of the pipeline 1 by installing screeds 5 along its vertical edges. At the same time, in order to prevent the weakening of the strength properties of the metal of the steel pipes of the pipeline 1, the use of the connection with it pad 4 is not allowed for welding.

Around the circumference of the defective section of pipeline 1, a reinforcing mesh 10 is installed with a width approximately equal to the width of the upper 7 and lower 8 halves of the repair case, and with a radius approximately 50 mm greater than the radius of the outer surface of the pipe (taking into account its insulating coating) in this section of pipeline 1. Under the lower part of the defective section of the pipeline 1, the lower half of the repair case 8 is brought in and its sides are connected to the pipeline 1; it is suspended on slings 11, the ends of which are attached to the traverse 12. As a result, the position of the lower half of the repair case 8 is fixed relative to the defective section of the pipeline 1, when In this case, the upper half of the repair case 7 is fixed in the open position by temporary attachment to the slings 11 closest to it.

The space between the lower half of the repair case 8 and the pipeline 1 is evenly filled with a previously prepared cement-sand mortar 13, preventing the formation of voids in it. In the upper part of the pipeline 1, at the place of the subsequent installation of the upper half of the repair case 7, a cement-sand mortar 13 is applied in an amount not less than the volume of the space between the upper half of the repair case 7 and the upper part of the defective section of the pipeline 1.

The upper half of the repair case 7 is disconnected from the slings 11, lowered with the necessary force onto the previously applied layer of cement-sand mortar 13 and rigidly welded to the lower half of the repair case 8 from the side opposite to the side with the loops attached to it 9. Cut off the loops 9 and on this side, the upper 7 and lower 8 halves of the repair case are also welded together. After holding the cement-sand mortar 13 for the time required for its final hardening, the pipeline 1 is made ready to resume pumping.

Thus, as a result of the implementation of the proposed technical solution, tightness and durability of the repair structure, including on pipelines with a high pressure of the pumped medium, as well as a decrease in local resistances in defective sections of pipelines, is ensured, which makes it possible to achieve an increase in the efficiency and reliability of local repair of an existing pipeline.

Claims (6)

A method of local repair of an existing pipeline, which consists in the fact that: - at the first stage of pipeline repair, pumping through the pipeline is stopped, at the place of the repaired defect, insulation is removed, its edges are leveled, a rectangular technological hole is formed, the outer surface of the pipeline is cleaned from corrosion along the perimeter of the technological hole, an insert is prepared according to the size of the technological hole and rigidly connected to lining, prepare the upper and lower halves of the repair case; - at the second stage of pipeline repair, an insert is installed in the technological hole, a patch is connected to the adhesive composition with the outer surface of the pipeline cleaned from corrosion and the patch is pressed against the pipeline with two ties installed along its vertical edges; - at the third stage of pipeline repair, a reinforcing mesh is installed around the circumference of the defective section of the pipeline, the lower half of the repair case is brought under the lower part of the defective section of the pipeline and suspended on slings attached to the traverse; - at the fourth stage of pipeline repair, the space between the lower half of the repair case and the pipeline is filled with a previously prepared cement-sand mortar, a cement-sand mortar is applied to the surface of the pipeline in the place of subsequent installation of the upper half of the repair case; - at the fifth stage of pipeline repair, the upper half of the repair case is lowered, it is rigidly welded to the lower half of the repair case, the slings are removed, the defective section of the pipeline is maintained until the final hardening of the cement-sand mortar and the pipeline is ready for pumping.

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