RU2631473C1 - Method of repairing pipeline in flooded area and caisson for its implementation - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: at least four caissons are delivered to the site of a selective repair and are sequentially mounted on a pipe upside down by means of support rollers, fixed to the pipe by a belt, then the caissons are set in the working position by turning them by 180°. From the caisson sluices and the working space of the chambers, water is pumped by a pump. In the first caisson, the pipe section is cleaned of the old insulation. In the second caisson, corrosion foci are removed from the area cleaned of the old insulation, small repairs of the pipe surface are made, and flaw detection is performed. In the third caisson, the pipeline section is blown and dried, and a protective coating is applied to it. In the fourth caisson, the output quality control of the coating is carried out, double blowing and drying of the treated pipe section are carried out. The column of caissons is moved along the pipe, and the described cycle of works is repeated on the next section of the pipe in the first, second, third, and fourth caissons until defects are eliminated throughout the pipeline, after which the caissons are dismantled. Wherein, at the initial stage, the works are performed only in the first caisson, and the column is moved, then the works are performed in the first and the second caisson, then in the first, the second and the third caisson, and then in each caisson. The design of the caisson is also proposed.

EFFECT: high-quality and eco-friendly repair without lifting the pipe above the water mirror due to the consistent performance of works in several caissons.

5 cl, 3 dwg

Description

The invention relates to the repair of the linear part of the main pipelines running in swamps or in significantly watered terrain.

In practice, repairing a pipeline in a swamp or heavily watered terrain is accompanied by a number of works to ensure the patency of heavy lifting equipment: the construction of a pit, the addition of imported soil, the construction of wooden platforms and porches. The drainage and restructuring of the ecosystem of water bodies also has negative consequences for the environment.

The prior art method of mounting a detachable working chamber for repair of underwater pipelines on rivers (RF patent No. 2224170, IPC F16L 55/18, publ. 02.20.2004), in which the pipeline is freed from the ground, a foundation pit is formed under the pipe for installing the camera to the ground, immerse and start the lower part of the chamber under the site of damage, match the bottom of the chamber with the pipe and fix the camera. Immerse the upper part of the chamber and pair it with the bottom, hermetically connect the upper and lower parts of the chamber, seal the interface between the pipeline and the chamber, extinguish the buoyancy of the chamber and pump out water from it. Additionally, excavation is carried out for laying the folding platforms fixed on the sides of the lower part of the detachable chamber, and buoyancy is extinguished by pouring the soil onto the folding platforms. The stability of the chamber in the water stream, in the open water surface, is carried out by stretch marks with anchors, and in winter conditions - by means of longitudinal beams frozen in the ice layer, while stretch marks or beams are attached to the upper part of the chamber beyond the water level.

The disadvantage of this method is the high complexity, because to carry out repair work it is necessary to carry out the operation to repay buoyancy, which is carried out by filling the soil on folding platforms, and the stability of the device for performing repair work is provided by extensions with anchors.

A known method of repair of underwater pipelines (RF patent №2325578, IPC F16L 1/26, publ. 05/27/2008), in which defects of the pipeline are detected by non-destructive testing. A caisson is installed on the defective section of the pipeline, water is displaced from its chamber by filling it with protective gas, the working pressure of the pipeline is reduced to a pressure equal to the protective gas pressure in the caisson, the surface of the defective section is cleaned and non-destructive, and defects are eliminated by welding in the protective gas environment. The caisson is dismantled and a sleeve is installed around the repaired section of the pipeline with the formation of a cavity between its inner surface and the outer surface of the pipeline. The coupling is sealed along the longitudinal and end flanges, and water is displaced from its cavity. The cavity is filled with expanding cement, followed by its compaction.

The disadvantage of this method is the difficulty of creating working conditions, since the pipeline is repaired in a closed caisson and under water (it is necessary to create pressure inside the caisson, which leads to additional costs, as well as filling the space between the coupling and the pipe requires spending on the coupling itself and the filler, in this case expanding cement), in addition, the limited volume of the caisson for repair work complicates the implementation of the method.

A known method of repair of an underwater pipeline (RF patent No. 2516996, IPC F16L 1/26, published on 05.27.2014), in which the insulation layer is removed from the damaged section of the pipeline, the size of the defect in the pipeline wall is determined by visual-measuring and / or ultrasonic ACFM control and / or control. Then, underwater grinding of the pipe surface is carried out by means of a hydraulic grinding machine until the defect is removed and the residual wall thickness of the pipeline at the grinding point is determined by means of an ultrasonic thickness gauge. Moreover, with a residual thickness of less than 80% of the nominal wall thickness, a repair sleeve is installed and a protective insulating layer is applied to its surface, and with a residual thickness of more than 80%, a protective insulating layer in the form of a mastic reinforced tape is applied to the polished surface of the pipeline.

The disadvantage of this method is the limited applicability and narrow localization, since such a repair under water does not provide easy access to the entire surface of the pipe, and this method does not allow the application of protective insulating roll materials by spiral winding, as in the case of work on hard ground.

A caisson for repair of underwater pipelines is known from the prior art (RF patent No. 101187, IPC E02D 25/00, published on 08/10/2011) containing a chamber from the upper and two lower parts, a means for sealing the chamber on the pipeline, arched cutouts in the form of a semicircle made in the end walls of the upper part of the chamber, the diameter of which corresponds to the diameter of the pipeline, the upper part is made with an opening for connecting the shaft, while each of the lower parts of the chamber is pivotally connected on the sides to the upper part of the chamber, and in opposite end walls of each of the lower parts of the chamber are cut out in the shape of a quarter of a circle for an airtight installation on the pipeline when they are closed, the camera is equipped with rotation mechanisms of the lower parts of the camera, an installation frame rigidly fixed to the upper part of the camera, with means for installing the camera on the pipeline placed on it, as well as devices for fixing the camera on the ground, mounted on the end walls of the camera.

The disadvantage of this caisson is its complex structural implementation.

A well-known caisson for repair of underwater pipelines (RF patent No. 2291936, IPC E02D 23/02, published on January 20, 2007), including a chamber with stiffeners, consisting of two detachable parts, upper and lower, a shaft, interchangeable rings, interchangeable detachable clamps, while stiffeners are located inside the chamber; interchangeable rings are made of shells interconnected by annular ribs; a sealing gasket between the pipeline and interchangeable rings with crimp gland bushings is made of soft rubber sheet; detachable clamps are installed on the bottom of the camera with the possibility of radial displacement of them relative to interchangeable rings; flanges with hinged bolts and nuts are installed on the upper and lower parts of the chamber along the perimeter of the connector, and the gaskets in the flange connections of the upper and lower parts of the chamber, the shaft sections between each other and with the coaming of the upper part of the chamber are made of high-wear sheet vacuum rubber and recessed into one from flanges.

The disadvantage of this caisson is its complex structural design and the narrowing of functionality due to insufficient chamber volume for repair work.

A device is known for repairing pipelines laid in swamps (RF patent No. 2111406, IPC F16L 55/18, publ. 05/20/1998), comprising a housing, the end walls of which have interchangeable half flanges and aprons for sealing the interface between the housing and the pipeline. The housing is made of separate working and intermediate blocks, while the working blocks are installed in the places of repair work and are made so that they form a free space between the blocks and the pipeline, and the intermediate blocks are made according to the diameter of the pipeline.

The disadvantage of this device is limited functionality, since the design of the block system of the housing does not provide free access to the entire repaired section of the pipeline.

The problem solved by the invention is to ensure high-quality and environmentally friendly repair of the pipeline in a significantly flooded area, without lifting the pipe above the water mirror.

The technical result of the invention is to increase the efficiency and reliability of pipeline repair work, as well as simplifying the design of the caisson for performing repair work.

The problem is solved and the technical result is achieved by a method of repairing a pipeline in a flooded area, in which a repair string of at least four caissons is placed along the pipeline thread, the caissons are delivered to the spot of selective repair, the first, second, third and fourth caissons are mounted sequentially on the pipe upside down support rollers and fix them on the pipe with a belt, then set the caissons in working position by turning them through a winch through 180 °, pump water out of the locks with a pump the caissons and the working space of the caisson chambers, after that, in the first caisson, the pipe section is cleaned from the old insulation using a local repair machine, the column of caissons is moved along the pipe to ensure that the pipe section processed in the first caisson overlaps, the cleaning of the next pipe section from the old insulation in the first the caisson and at the same time in the second caisson remove the foci of corrosion, make a minor repair of the pipe surface and perform a flaw detection of the pipe section, move the column of caissons further length of pipe, repeat the cleaning of the next pipe section from the old insulation in the first caisson and at the same time in the second caisson remove the centers of corrosion, make a minor repair of the pipe surface and make a flaw inspection of the next cleaned pipe section, move the casing string further along the pipe, repeat the cleaning of the next pipe section from the old insulation in the first caisson, at the same time in the second caisson, remove the foci of corrosion, make minor repairs to the surface of the pipe and perform a defectoscopy of the next section of the pipe, also e at the same time in the third caisson blow and dry the first section of the pipe and apply a protective coating on it, move the column of caissons along the pipe and sequentially repeat the work on the pipe sections in the first, second and third caissons, while simultaneously performing quality control in the fourth caisson coatings, double blow and dry the treated pipe section, then move the casing string and repeat the described cycle of work on the next pipe section in the first, second, third and fourth m caissons to eliminate defects throughout the pipeline, whereupon the dismantling of the caissons.

According to the invention, when large defects are detected in the second caisson, two caissons are additionally mounted on both sides of the pipe’s defective pipe section, then using the special cutting equipment the defective pipe section is cut out, and plugs are installed at the ends of the cut section and the pipe, the cut pipe section is delivered by water using floating equipment on hard ground, where a new identical pipe section is prepared, which is delivered to the place of repair of the pipeline, where installation and repair are carried out on the cut section Ku with prior removal of the plugs, then a recovered pipe section protective coating is applied manually or using a local repair of the machine.

According to the invention, the caissons are delivered to a spot repair site located in a flooded area, by water on special floating equipment.

According to the invention, each caisson from the column is pre-mounted on the pipe in a place where solid soil is present, then a transportation winch is attached to it, and cords are transported along the pipeline to the spot for selective repair.

According to the invention, the task is achieved by a caisson for repairing a pipeline, including an all-metal rectangular chamber with a bottom, two side and two end walls, which are made through arcuate openings with an arc radius corresponding to the radius of the pipe, allowing the camera to fit to the outer surface of the pipe, and inside chambers on the side of both end walls have locks for collecting and pumping water and water locks, which are located along the edge of the arcuate openings, and on the walls at least three support rollers are installed for the locks to center the caisson on the pipe, and at least two straps are attached to the side walls of the chamber to fix the caisson on the pipe, and fasteners are installed on the end walls of the chamber to interface with the transport winch.

The technical result of the invention is achieved by creating local zones of the drained pipe, where it becomes possible to carry out all the steps for repair, to provide easy access to the lower surface of the pipe, which allows workers to control the quality of the coating throughout the body of the pipe. The all-metal construction eliminates the possibility of water entering the workspace, which qualitatively affects the properties of protective coatings. Due to its own positive buoyancy of the pipe and rigid fixation with a belt, the caisson remains afloat, which also prevents water from entering.

The use of this caisson allows eliminating the costs of the construction of the pit and reducing the time of work without violating the integrity of the natural zone.

The invention is illustrated by drawings, where in FIG. 1 is a perspective view of a caisson; FIG. 2 is a cross-section of a caisson, in FIG. 3 - top view of the caisson.

The caisson (Fig. 1, 2, 3) includes an all-metal rectangular chamber 1 with a bottom 2, two side 3 and two end walls 4. On the end walls 4 of the chamber, through arcuate openings 5 are made with an arc radius corresponding to the radius of the pipe 6, making it possible for the chamber 1 to adhere to the outer surface of the pipe. Inside the chamber 1, from the side of both end walls 4 there are locks 7 for collecting and pumping water and hydraulic locks 8, which are located along the edge of the arcuate openings 5. The device for centering the caisson on the pipe is made in the form of support rollers 9, mounted on the walls 10 of the locks 7. K a belt 11 is attached to the side walls 3 of the camera for fixing the caisson on the pipe 6, and a fastening device 12 is mounted on the end wall 4 of the camera with the possibility of interfacing with a transport winch (not shown).

The method is implemented as follows.

The repair casing of caissons is placed along the string of a large-diameter pipeline (1420 mm), the caissons are delivered to the spot of selective repair, the first, second, third and fourth caissons are mounted sequentially on the pipe 6 upside down 4 by means of the support rollers 9 and they are fixed on the pipe by a belt 11, then the caissons are installed in the working position by turning them through a winch through 180 °, the pump is pumped out water from the locks of the 8 caissons and the working space of the chambers 1 caissons, then in the first caisson the pipe section is cleaned of old Using a local repair machine, move the column of caissons along the pipe to ensure that the pipe section processed in the first caisson overlaps, repeat the cleaning of the next pipe section from the old insulation in the first caisson and at the same time remove the corrosion centers in the second caisson, make a minor repair of the pipe surface and perform a flaw detection pipe section, then move the column of caissons along the pipe, repeat the cleaning of the next pipe section from the old insulation in the first caisson and simultaneously in the second caisson remove the foci of corrosion, make minor repairs to the pipe surface and perform a flaw detection of the next cleaned pipe section, move the column of caissons along the pipe, repeat the cleaning of the next pipe section from the old insulation in the first caisson, simultaneously remove the corrosion centers in the second caisson, and make minor repairs to the pipe surface and perform a flaw detection of the next pipe section, also simultaneously in the third caisson blow and dry the first pipe section and apply a protective coating to it, change then they press the column of caissons along the pipe and sequentially repeat the work on the pipe sections in the first, second and third caissons, while simultaneously in the fourth caisson output quality control of the coating is carried out, double blowing and drying of the treated pipe section is carried out, then the column of caissons is moved and the described cycle is repeated works on the next pipe section in the first, second, third and fourth caissons until the defects are eliminated throughout the pipeline, after which the caissons are dismantled.

Necessary equipment for repair: a winch for installing caissons in a working position, a pump with a diesel station for pumping water, a local repair machine, a container for collecting remote insulation, a drying and insulation machine, a thermal container for storing insulation mastic, a flaw detector, cutting, welding and others The equipment necessary for repair is placed on a special barge or pontoon, which, when operating, are docked with a caisson.

If large defects are detected in the second caisson, the main casing string continues to move along the pipe, and two caissons are additionally mounted on both sides of the pipe to the defective pipe section, then the defective pipe section is cut out using special cutting equipment, and plugs are installed at the ends of the cut section and pipeline, the cut section of the pipe is delivered by water using floating means to solid soil, where a new identical pipe section is prepared, which is delivered to the pipeline repair site, where cut portions produce assembling and welding with prior removal of the plugs, then a recovered pipe section protective coating is applied manually or using a local repair of the machine.

Caissons are delivered to the spot for repair in two possible ways.

In the first case, the caissons are delivered by water on special watercraft.

In the second case, each caisson from the column is pre-mounted on a pipe in a place where solid soil is present, then a transportation winch is attached to it, and cords are transported along the pipeline to the spot for selective repair.

Thus, the proposed method for repairing large-diameter pipelines located in flooded areas, and the caisson for its implementation provide high-quality and environmentally friendly repairs without lifting the pipe above the water mirror due to the consistent performance of work in several caissons with a simple and reliable design.

Claims (5)

1. A method of repairing a pipeline in a flooded area, in which a repair string of at least four caissons is placed along the pipeline thread, the caissons are delivered to the spot of selective repair, the first, second, third and fourth caissons are mounted sequentially on the pipe upside down by means of support rollers and fix them on the pipe with a belt, then the caissons are installed in the working position by turning them through the winch through 180 °, pumping water out of the caisson locks and the working space of the caisson chambers with a pump, then in the first ohm caisson, the pipe section is cleaned from the old insulation by means of a local repair machine, the column of caissons is moved along the pipe to ensure that the pipe section processed in the first caisson is overlapped, the cleaning of the next pipe section from the old insulation in the first caisson is repeated, and the foci of corrosion are removed at the same time, make a minor repair of the pipe surface and make a defectoscopy of the pipe section, then move the column of caissons along the pipe, repeat the cleaning of the next pipe section from the old and olations in the first caisson and at the same time in the second caisson remove the foci of corrosion, make a minor repair of the pipe surface and make a defectoscopy of the next cleaned pipe section, move the casing string further along the pipe, repeat the cleaning of the next pipe section from the old insulation in the first caisson, and simultaneously remove the second caisson foci of corrosion, make minor repairs to the surface of the pipe and make a flaw detection of the next section of the pipe, also simultaneously blowing and drying the first section of the pipe and apply a protective coating on it, move the column of caissons along the pipe and sequentially repeat the work on the pipe sections in the first, second and third caissons, while simultaneously in the fourth caisson output quality control of the coating is carried out, double blowing and drying of the treated pipe section are carried out , then the column of caissons is moved and the described cycle of work is repeated on the next pipe section in the first, second, third and fourth caissons until the defects are eliminated throughout the pipeline, after which dismantle caissons. 2. The pipeline repair method according to claim 1, characterized in that when large defects are detected in the second caisson, two caissons are additionally mounted on both sides of the defective pipe section, then the defective pipe section is cut out using special cutting equipment, and at the ends of the cut section plugs are installed in the pipeline, the cut section of the pipe is delivered by water using floating means to solid soil, where a new identical pipe segment is prepared, which is delivered to the pipeline repair site, where the cut-out In this section, installation and welding is performed with preliminary removal of plugs, then a protective coating is applied to the restored pipe section manually or using a local repair machine. 3. A method of repairing a pipeline according to claim 1, characterized in that the caissons are delivered to a spot repair site located in a flooded area, by water on special floating equipment. 4. A method of repairing a pipeline according to claim 1, characterized in that each casing from the column is pre-mounted on the pipe in a place where solid soil is present, then a transportation winch is attached to it and dragging along the pipeline delivers coffers to the spot of selective repair. 5. A caisson for repairing a pipeline, including an all-metal rectangular chamber with a bottom, two side and two end walls, on which through arcuate openings are made with an arc radius corresponding to the radius of the pipe, allowing the camera to fit to the outer surface of the pipe, and inside the camera from the side both end walls have locks for collecting and pumping water and water locks, which are located along the edge of the arcuate openings, and at least three support rollers for Centering the caisson on the pipe, and at least two straps are attached to the side walls of the chamber to fix the caisson on the pipe, and fasteners are installed on the end walls of the chamber to pair with the transport winch.

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