RU2375632C1 - Procedure of pipeline repair - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention refers to methods of repair of accident hazardous sections of pipelines during continuous transporting of product. Cylinder semi-cases in form of pipe courses and end walls are installed on a damaged section of the pipeline. Thickness of the pipe course is 1/5-1/2 of pipeline wall thickness. Two couples of half-rings with hardening sealant preliminary applied at their internal surfaces are arranged on both sides of a damaged section of the pipeline. Further sealant is conditioned. The half-rings are welded to each other. Upon that the semi-cases are installed so, that their end walls are located in the middle of the half-rings. The semi-cases are sealed by welding. Edges of half-rings and semi-cases are lock-type cut for welding. Dimension of a circular gap is chosen from ratio 1/30 - 1/8 from external diametre of the pipeline. Composite hardening material under excessive pressure not over 25% of working pressure in the pipe is supplied into the circular gap between the semi-cases and the pipeline. Composite material is conditioned till hardening.

EFFECT: increased safety factor of repaired section of pipeline not lower of its original level, decreased specific quantity of metal of structure, simplification of repair procedure, and increased operation life of pipeline.

4 cl, 1 dwg

Description

The invention relates to methods for repairing lengthy hazardous sections of a pipeline through which oil, oil products or gas are transported without stopping pumping the product.

A known method of repairing local damage to the pipeline (RF patent No. 2213289 from 10.10.2001, publ. 09.27.2003) transporting steam, steam condensate or hot water by installing on the damaged section of the pipeline two metal cylindrical half-shells repeating the radius of the damaged pipes, pulling them together and filling with quick-hardening sealant the space between the half-shells and the pipe. Two half couplings are installed as half shells, each having annular grooves along the ends of at least 3 × 3 mm in size, an annular central groove with a depth of at least 3 mm and a width of 20 mm greater than the damage size of the pipe and two fittings, one of which is connected to the central groove, and the other, with an annular groove at the end, combine the place of local damage to the pipe with one of the central fittings, withstand the time required to heat the coupling half to the temperature of the pipeline, and fill it with thermoset ring sealant The grooves through the end fittings withstand the time required for the sealant to cure, localizing the damage zone, and then through the central fitting under pressure higher than the pressure of the transported product, the calculated amount of thermosetting sealant is required to completely fill the localized space between the coupling halves and the damaged pipe. A thin layer of sealant is applied to the supporting surfaces of the coupling halves, by which they are in contact with each other, after which the coupling halves are tightened with bolts and can withstand the time required for heating the coupling halves.

When performing the method, it is necessary to carry out an increased number of technological operations using a large number of connecting and sealing elements and pipelines to pump the sealant into the repair zone, which reduces the reliability of the repair and leads to its cost increase. In addition, some details for the implementation of the method have increased metal consumption, which also increases the cost of repair.

A known method of repairing a pipeline (RF patent No. 2191317 from 01/05/2001, published on 10/20/2002), including the installation of two coupling halves on a damaged section of the pipeline with the formation of an annular gap between the coupling halves and the pipeline. There are nozzles on the coupling halves. The coupling halves are joined together by welding, the ends of the coupling halves are sealed, and a composite cured material is fed into the annular gap between the coupling and the pipeline through the inlet pipe until it appears in the outlet pipe. As a composite material, a cold curing polymer composition based on epoxy dianes is used.

The disadvantage of this method is the large metal consumption of the device for implementing the method, which leads to an increase in the cost of repair of the pipeline. The heavier metalwork of repair elements requires the use of hoisting-and-transport devices and mechanisms with increased carrying capacity, which also affects the cost of repairs. The sealant is introduced into the ends of the coupling halves already in the assembled design, which significantly complicates the process, makes it less reliable (due to the possibility of the formation of voids and shells due to the uneven application of the sealant).

The objective of the proposed method of repair is to restore the operability of an extended hazardous pipeline without stopping the pumping of the product, increasing the safety factor of the pipeline in the repaired area not lower than its initial level, reducing repair costs, increasing the life of the pipeline.

The technical result is to increase the safety factor of the pipeline on the repaired section not lower than its initial level, reduce the metal consumption of the structure, simplify the repair method, increase the life of the pipeline, reduce the number of equipment during technological operations, reduce the cost of repairing the pipeline.

The technical result is achieved in that in a method of repairing a pipeline, including installing on a damaged section of a pipeline cylindrical half-shells with nozzles with the formation of an annular gap between the half-shells and the pipeline, connecting the half-shells to each other by welding, sealing the ends of the half-shells and feeding into the annular gap between the half-shells and the pipeline through the inlet pipe of the composite curable material until it appears in the outlet pipe. Cylindrical half-shells are made of cylindrical shells and end walls, while the thickness of the cylindrical shells is 1 / 5-1 / 2 of the wall thickness of the pipeline being repaired, two pairs of half rings with previously cured on their inner surface are installed on the pipe to be repaired with a sealant, withstand until it is cured, after which the half rings are welded together, and then half-shells are installed on them so that their end walls are located in the middle not a half ring. The sealing of the half-shells is carried out by welding the end walls with half rings, after which the half-shells are welded together, the size of the annular gap is selected from the ratio (1 / 30-1 / 8) d, where d is the external diameter of the pipeline.

Grooves can be made on the inner surface of the periphery of the half rings, which are filled with a curing sealant, which increases the degree of sealing of the annular gap and the strength of the sealing elements. The edges of the half rings and half shells for welding are performed by cutting of the castle type, which increases the safety of work in the case of using flammable sealants.

After feeding the composite cured material into the annular gap through the inlet pipe, an overpressure of no higher than 25% of the working pressure in the pipe is applied and is kept during the curing time of the composite material, thereby achieving a reduction in stresses in the pipe, which directly contributes to the durability of the pipeline. The implementation of the half-shells of cylindrical shells with a thickness of 1 / 5-1 / 2 of the wall thickness of the repaired pipeline gives a gain in metal consumption, is a necessary and sufficient value to ensure the strength and rigidity of the structure, does not require the use of lifting and transport devices and mechanisms with increased carrying capacity . All this significantly reduces the cost of pipeline repair.

Installation on the repaired pipe on both sides of the defect of two pairs of half rings with hardening sealant previously applied on their inner surface compensates for irregularities in the pipeline, thereby reducing distortions when installing the end walls of the half-shells.

The installation of half rings and half-shells with the claimed features provides an increased degree of sealing of the annular gap. This is facilitated by the fact that the end walls of the half-shells are installed in the middle of the half rings, thereby providing the possibility, when filling the annular gap with composite material, to create pressure on that part of the half-ring that is located inside the half-shells. Eliminating the effect of welding on the repaired pipeline (since the walls of the half-shells are welded to the half-ring), they achieve safe repair work. All this improves the quality of repairs and extends the life of the repaired pipeline.

The choice of the annular gap size depending on the external diameter of the pipeline in the claimed range provides such structural strength that, with a minimum consumption of composite material, the pipeline cannot be deformed under the unregulated impact of third-party equipment (for example, an excavator) during earthwork.

The implementation of the method is illustrated in the drawing, which shows a longitudinal section of a repair device installed on the repaired pipeline, where it is indicated:

1 - inlet pipe;

2 - cylindrical shell;

3 - annular gap with composite cured material;

4 - end wall;

5 - a half ring;

6 - groove filled with curing sealant;

7 - pipeline;

8 - output pipe;

9 - weld.

An example of a specific implementation of the method is the following.

On the pipe 7 with an outer diameter of 560 mm and a wall thickness of 10 mm, having a defect, for example, in the form of corrosion of the outer wall of the pipe, two pairs of half rings 5 are pre-installed on both sides of the defect with cured sealant previously applied to their inner surface (including grooves). As a curable sealant, a composition based on ED-20 epoxy resin, L-20 polyamide resin and Portland-500 cement filler was manufactured and tested. After the sealant has hardened, the half rings are welded together, then the half shells are installed so that their end walls 4 are located in the middle of the half rings 5. The half shells are welded to the half rings, after which the half shells are welded together. The edges of the half rings and half shells for welding are made by cutting of the castle type. Moreover, to reduce the metal consumption of the structure, the thickness of the cylindrical shell 2 is made of a steel sheet with a thickness of 2-2.5 mm with an inner diameter of 680 mm. The annular gap between the wall of the pipe 7 and the cylindrical shell 2 in this case will be 60 mm. After all the necessary elements for repair have been installed on the pipeline, a curing composite material, for example, cement mortar, is supplied through the inlet pipe 1. The supply of composite material is stopped at the moment when it appears in the outlet pipe 8. Then, an overpressure of no higher than 25% of the pressure in the pipeline is supplied through the inlet pipe and held for the curing time of the composite material.

The calculations and experimental testing of all the necessary elements for repair confirm the new technical result.

Claims (4)

1. A method of repairing a pipeline, including installing cylindrical half-shells with nozzles on a damaged section of the pipeline with the formation of an annular gap between the half-shells and the pipeline, welding the half-shells to each other, sealing the ends of the half-shells and supplying a composite solid material to the annular gap between the half-shells and the pipe through the inlet pipe material before it appears in the outlet pipe, characterized in that the cylindrical half-bodies are made of cylindrical both gulls and end walls, while the thickness of the cylindrical shells is selected based on 1 / 5-1 / 2 of the wall thickness of the pipeline being repaired, two pairs of half rings with curing sealant previously applied on their inner surface are installed on the pipeline being repaired, withstand until it curing, after which the half rings are welded together, and then half-shells are mounted on them so that their end walls are located in the middle of the half rings, the ends of the half-shells are sealed vlyayut by welding end walls with the half-rings, then the half-shells are welded together, the size of the annular gap is selected from (1 / 30-1 / 8) d, where d - diameter of the external pipe. 2. The pipeline repair method according to claim 1, characterized in that grooves are made on the inner surface of the periphery of the half rings, which are filled with a curing sealant. 3. The method of repairing a pipeline according to claim 1, characterized in that the edges of the half rings and half shells for welding are performed by cutting a lock type. 4. The method of repairing the pipeline according to claim 1, characterized in that after feeding into the annular gap between the half-shells and the pipe a composite cured material through the inlet pipe, an overpressure of not higher than 25% of the working pressure in the pipe is applied and can withstand the curing time of the composite material.

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