RU2788782C1 - Method for fire-free repair of defective sections of pipelines without changing pumping modes - Google Patents

Abstract

FIELD: pipelines construction and repair.

SUBSTANCE: invention relates to the field of construction and repair of pipelines of any method for laying, as well as other cylindrical structures, such as pressure vessels. A method for repairing non-through external defects in linear sections of pipelines is proposed. According to the method, the surface of the repaired section of the pipeline 1 is prepared, dust removal, moisture removal, degreasing with acetone, treatment with a rust converter acting as a primer, filling the cavity of the defect 2 with a fast-hardening composite paste, applying a thin uniform layer of polymer adhesive composition to the prepared area. At the same time, the inner composite bushing 3 is first glued, then on top of the inner composite bushing 3, overlapping the horizontal joint 8 of the inner bushing, the outer composite bushing 4 is glued onto a thin uniform layer of adhesive composition, on top of which composite screed couplings 5 are mounted, consisting of two coupling halves connected to each other on one side by hinges 7, and on the other side by coupling screws 6.

EFFECT: proposed method allows, without the use of welding and other fire processes, as well as without reducing the working pressure in the pipeline, to repair non-through mechanical and corrosion defects of any length along the axis of the pipeline section being repaired, to stop defect formation, to strengthen the walls of the pipeline and restore the bearing capacity to defect-free level.

11 cl, 4 dwg,1 tbl

Description

The invention relates to the field of construction and repair of main, field, technological and other pipelines of any method of laying, as well as other cylindrical structures, such as pressure vessels [F16L37/00, F16L 55/17, F16L 55/18].

During the construction and operation of the above facilities, as a result of corrosion, mechanical, electrochemical and other processes, various defects appear (ulcers, shells, cavities, pittings, cracks, fistulas, dents, corrugations, patches, chopsticks, etc.), including unacceptable for the safe operation of the pipeline. Pipeline damage can be both local and group in nature, sometimes affecting sections with a length of tens and even hundreds of meters. Pipeline owners are now placing increased demands on their repair. Repair must be fast, reliable, fully restore the bearing capacity of pipes damaged by defects for the entire remaining service life of the pipeline, that is, be a permanent repair method, and be carried out without changing the pumping modes.

Keep pumping modes unchanged using the widely used method of repairing pipelines using composite-coupling technology - KMT (GB 2210134 A, 06/01/1989, RU 2191317 C2, 10/20/2002, RU 113811 U1, 02/27/2012, RU 129593 U1, 06/27/2012. 2013), as well as the method using spiral composite couplings of the “Clock Spring” type (RU 2108514 C1, 04/10/1993), is not possible, since both of these methods have one common drawback: their technologies involve the installation of repair structures on defective sections of pipelines , at a reduced relative to the working pressure, that is, when the repaired pipeline has an outer diameter smaller than at working pressure.

Such designs for repairing pipelines as "Composite pipe coupling" (RU 73331 U1, 05/20/2008), "Universal cone coupling" (RU 148064 U1, 11/27/2014) and "Composite cone coupling" (RU 174392 U1, 10/11/2017). But they, like KMT and Clock Spring couplings, have another drawback that prevents their even wider use - this is that, when repairing extended defects, that is, defects with a length along the pipe axis that exceeds the maximum length of the repair structure, it is required their sequential installation end-to-end, or at the closest possible distance from each other, which in most cases is difficult to do, both for technical and financial reasons.

As a prototype, a method for repairing defects in the concreting of a section of an underwater pipeline and a device for its implementation (RU 2619954, 22.05.2015) was chosen.

The method selected for the prototype is used to repair damage to the concrete lining of underwater pipelines without changing the pumping modes, but it does not provide for the repair of defects in the pipe wall. Unlike the prototype, the objective of the present invention is to provide the possibility of fire-free repair of non-through defects in the wall of metal pipelines, regardless of the method of laying them, without reducing the pressure and flow rate of the pumped product, that is, without changing the pumping modes. Repaired according to the proposed method, the defects can be single, locally grouped, not extended and extended, both along the perimeter of the pipe and along the axis of the pipeline. In addition, using this method, it is possible to repair defects protruding above the pipeline surface (patches, welded-in bolt heads, chopsticks, etc.), as well as defects at welded joints of pipeline sections and in their near-weld zones. It is also possible to use the proposed method for repairing non-through defects on the inner surface of the repaired pipeline.

The task of the claimed group of inventions is to eliminate the disadvantages of analogues of the prior art.

The technical result achieved from the implementation of the proposed technical solution is:

- ensuring the possibility of fire-free repair of non-through defects in the wall of metal pipelines, regardless of the method of their laying and regardless of their location, without reducing the pressure and flow rate of the pumped product, that is, without changing the pumping modes;

- increasing the operational reliability of the repaired pipeline, by restoring the bearing capacity of the repaired sections to the state of a defect-free pipe and ensuring their safe operation during the entire service life of the repaired pipeline;

- in a significant reduction in the terms of repair work and optimization of their cost, including due to the reduction in the cost of organizational and technical measures for their implementation, in view of the absence of the need to use welding equipment, lifting mechanisms, pressure pumps and other technical devices in the repair process. The optimal number of team members for the repair of defects in pipelines with diameters from 89 mm to 1420 mm using this method is three people.

The claimed technical result is achieved by the proposed method of fireless repair without changing the modes of pumping non-through external and internal mechanical and corrosion defects of linear sections of pipelines with a structurally even outer surface, which consists in preparing the surface of the repaired area, dedusting, removing moisture, degreasing with acetone, processing with a rust converter that performs the role of a primer, filling the defect cavity with a fast-hardening composite paste, applying a thin uniform layer of polymer adhesive to the prepared area and mounting a full-encompassing composite repair structure on it, while first gluing the internal composite sleeve, then over the internal composite sleeve, overlapping the horizontal joint of the internal sleeve, an outer composite sleeve having a smooth inner and outer surface is glued onto a thin uniform layer of adhesive composition, on top of which they are mounted tie-down composite couplings, consisting of two half-couplings, connected to each other on one side pivotally, and on the other hand, one per coupling with coupling screws.

According to one of the options, the inner composite bushing has a thickness commensurate with the nominal thickness of the pipe wall along the axis LRC, which is determined by the formula LRC = LD + 2LВ, where LВ is the defect overlap length along the pipe axis, satisfying the condition LВ ≥ 0.5√Dt ≥ 0.05 m, where D is the outer diameter, and t is the wall thickness of the repaired pipeline, and rounding up to the values LRK = 0.333 m, LRK = 0.667 m, or LRK = 1 m, then over the internal composite sleeve, overlapping the horizontal joint of the inner sleeve, on a thin uniform layer of adhesive composition, an outer composite sleeve having a smooth inner and outer surface is glued with a thickness commensurate with the nominal wall thickness of the repaired pipeline, on top of which they are mounted with a thickness commensurate with the wall thickness of the repaired pipeline and a length LM calculated from the expression LM = 0.167LB, where LB is the length of the base repair structure, at a distance from the outer boundaries of the repair structure, p equal to 0.5LM, with an interval equal to LM, in the amount of k pieces, calculated from the expression k = 3n, where n = LRK / LB, composite couplings, consisting of two half-couplings connected to each other on one side by hinges, and on the other sides, one per coupling with coupling screws, twisted with a calibrated force.

According to one of the options, to repair non-through external defects at the welded joints of pipeline sections and in their near-weld zones, internal composite bushings with a thickness commensurate with the nominal wall thickness of the repaired pipeline are used with a selection for reinforcing the welded joint on their inner surface with a section size a*b, where a is the width +5 mm and b is the height +2 mm of the reinforcement of the welded joint according to the regulatory documentation for the repaired pipeline.

According to one of the options, to repair a pipeline section with an installation protruding above the pipe surface with a thickness no greater than the thickness of the internal composite sleeve, an internal composite sleeve is used with a selection for the installation protruding above the pipe surface, followed by filling the gaps between the installation and the boundaries of the sample under it in the internal composite sleeve and leveling the thickness of the installation with the thickness of the inner sleeve with quick-hardening composite paste flush +0.5 mm to the level of the outer surface of the inner sleeve without sampling.

According to one of the options, for the repair of non-through external defects with a length along the axis of the pipeline LD > 0.9 m, from the base repair structures with a length LB, a repair structure with a length LRC is made up, calculated by the formula LRC = nLB, where n is the number of basic repair structures, with internal composite bushings for repairing defects in sections with a structurally even surface, for repairing defects at welded joints of pipeline sections, as well as in their near-weld zones, and / or for repairing sections with installations protruding above the surface of the pipeline, which are installed so that the outer composite bushings overlap , both horizontal and vertical joints of internal composite bushings of length LM, determined from the expression LM = 0.167LB, and the number of composite couplings, calculated by the formula k = 3n - 1, where n is the number of basic repair structures in the composite repair structure, obtained after rounding up to an integer number value calculated by the formula n = (2LВ + LD)/LБ, where LВ is the defect overlap length along the pipe axis, satisfying the condition LВ ≥ 0.5√Dt ≥ 0.05 m, where D is the outer diameter, and t is the thickness the walls of the repaired pipeline were installed, overlapping the vertical joints of the external composite bushings, with an interval of LP in meters, equal to LP = 1.25LM, at a distance from the outer edges of the repair structure, equal to 0.5LP.

According to one of the options, when repairing non-through defects on the inner surface of flat sections of the repaired pipeline LD ≤ 0.9 m, as well as internal defects at welded joints and in their near-weld zones, the position of the defects is transferred to the outer surface of the repaired pipeline, the operation of filling defects with a fast-hardening composite paste is excluded and used to fix the location of the repaired internal defect at a distance of the pipeline for monitoring, using in-line diagnostics, its development beyond the repair structure, magnetic markers that are installed in front of the repair structure along the product with an orientation of 12 hours at a distance of no more 0.5 meters from her.

According to one of the options, when repairing non-through defects on the inner surface of structurally flat sections of the repaired pipeline LD > 0.9 m, as well as internal defects at welded joints and in their near-weld zones, the position of the defects is transferred to the outer surface of the repaired pipeline, the operation of filling defects with a fast-hardening composite paste is excluded and used to fix the location of the repaired internal defect at a pipeline distance for monitoring, with the help of in-line diagnostics, its development beyond the repair structure, magnetic markers that are installed in front of the repair structure along the product with an orientation of 12 hours at a distance not more than 0.5 meters from it.

According to one of the options, the composite bushings are made elastically deformed to the diameter of the pipeline being repaired and they are installed when the filling composite paste is in an uncured, deformable state to ensure tight and continuous contact between the defective section of the pipeline and the composite bushings in order to transfer the load from it to the reinforcing the repair structure took place without loss.

According to one of the options, the composite bushings are made elastically deformed to the diameter of the pipeline being repaired and they are installed when the filling composite paste is in an uncured, deformable state to ensure tight and continuous contact between the defective section of the pipeline and the composite bushings in order to transfer the load from it to the reinforcing the repair structure took place without loss.

According to one option, the same composite paste is used as a filling fast-hardening composite paste and a polymer adhesive composition.

According to one option, the same composite paste is used as a filling fast-hardening composite paste and a polymer adhesive composition.

The essence of the proposed method is as follows.

The main, field, technological and other pipelines of underground, surface, above-ground and underwater laying for the transfer of hydrocarbons, water and other liquid and gaseous products during operation may be subjected to mechanical, electrochemical and / or other effects, resulting in the formation of such pipeline defects as corrosion ulcers, pittings, dents, scratches, etc.

The presence of defects in pipelines, as well as its bends, sags, or changes in its length due to seasonal temperature fluctuations, as well as the performance of installation and welding work, contributes to the formation of sections that are in a stress-strain state, which leads to a decrease in the bearing capacity of the pipeline, reducing its resource life and the creation of emergency situations. In this regard, in these sections of pipelines, it is necessary to carry out repair work to strengthen them in order to restore the bearing capacity.

The proposed method allows repairing non-through external and internal mechanical and corrosion defects of any length along the axis of the pipeline section being repaired, removing ring and axial loads from it, thereby removing it from the stress-strain state, stopping defect formation, strengthening its walls and restoring the bearing capacity to defect-free level, by mounting on defective areas of repair structures without the use of welding and other fire processes, as well as without reducing the working pressure in the pipeline, that is, directly during its normal operation. The installation of repair structures includes the sequential execution of such operations as cleaning the repaired section of the pipeline from earth residues, insulation and other contaminants, preparing the surface of the repaired section to the first degree of cleaning in accordance with GOST 9.402-2004 (or St 3 according to ISO 8501), dedusting, for example , with a damp rag, removing moisture and degreasing the cleaned surface with acetone, treating with a rust converter, which also acts as a primer, filling the defect cavity with a fast-hardening paste, applying a thin uniform layer of adhesive to the area being repaired within the length of a single repair structure, installing an internal composite on the pipeline bushings for repairing external defects in linear sections with a structurally even outer surface - according to the first version of the proposed method, with a factory selection for a vertical welded joint - according to the second option, and with a special selection, when repairing protruding above the surface installation pipes - according to the third option, so that according to any of the options, the horizontal joint of the inner sleeve is located on the opposite side of the defect, applying a thin uniform layer of adhesive composition to the surface of the mounted inner sleeve, mounting an external composite sleeve over the inner sleeve with even outer and inner surface so that its horizontal joint is on the opposite side from the horizontal joint of the inner sleeve, installation on top of the outer sleeve of one, or several with an interval between each other not less than their length, single-bolt compression couplings, consisting of two half-couplings connected to each other in the grip of the pipe on one side is hinged, and on the other hand, with the help of tightening screws twisted with a calibrated force (one on each coupling), due to which each coupling is tightly pressed through two bushings to the surface of the pipeline, compressing it from the outside and creating a uniform pressure on the pipe the entire surface of the installed section external contact impact of a magnitude commensurate with the impact on the pipeline wall from the inside, created by the product pumped through the pipeline under operating pressure, which reduces to zero the total impact on the pipeline wall in the area of \u200b\u200binstallation of the repair structure, thereby removing from it, as ring, and longitudinal stresses, which leads to the prevention of further development of already existing defects and the formation of new ones, which, coupled with strengthening the wall of the defective section of the pipeline by thickening it by gluing composite bushings in two layers, returns it to the state of a defect-free pipe and restores the original structural strength pipeline. Repair of sections extended along the axis of the pipeline with single and group defects according to the first variant simultaneously with defects according to the second and third variant of the proposed method - this is the fourth variant of the proposed method, which consists in successively repeating the above technological operations so that the composite bushings are glued in a run-up, and so that the first and last shrink sleeves were installed at a calculated distance from the edge of the respective composite sleeves glued to the pipeline, and the shrink sleeves between them were located at equal intervals between them with the obligatory overlap of the vertical joints of the outer composite sleeves. At the same time, the thickness of each element of the repair structure is made commensurate with the wall thickness of the repaired pipeline.

On FIG. 1-4 show repair structures according to the first, second, third and fourth variants of the proposed method.

Fig. 1 illustrates the first option - this is a method for fire-free repair of external non-through defects with a length along the pipe axis of not more than 0.9 m in linear sections of pipelines with a structurally even surface without changing the pumping modes, using one repair structure.

Fig. 2 illustrates the second option - this is a method of fireless repair of external non-through defects at welded joints of pipeline sections and in their near-weld zones without changing the pumping modes, using one repair structure.

Fig. 3 illustrates the third option - this is a method for fire-free repair of pipeline sections with installations protruding above the pipe surface with a thickness not exceeding the nominal wall thickness and a length along the axis of not more than 0.9 m, without changing the pumping modes, using one repair structure.

Fig. 4 illustrates the fourth option - this is a method of fireless repair of external non-through defects with a length along the pipeline axis of more than 0.9 m without changing the pumping modes, using several repair structures.

The figures indicate: 1 - pipeline section being repaired, 2 - pipeline defect, the cavity of which is filled with fast-hardening polymer paste, 3 - internal composite sleeve, 4 - external composite sleeve, 5 - composite coupling, 6 - coupling screw, 7 - hinge, 8 - horizontal joint of the inner composite bushing filled with quick-hardening polymer paste, 9 - horizontal joint of the outer composite bushing filled with quick-hardening polymer paste, 10 - welded joint of pipeline sections, 11 - selection for the welded joint filled with quick-hardening polymer paste, 12 - installation protruding above the pipe surface, 13 - cavities, slots and gaps filled with fast-hardening polymer paste, 14 - vertical joint of external composite bushings, 15 - vertical joint of internal composite bushings.

The first version of the proposed method - fireless repair of external non-through defects with a length along the pipe axis of not more than 0.9 m on linear sections of pipelines with a structurally even surface without changing the pumping modes, using one repair structure - is carried out as follows.

On the pipeline with an outer diameter D with a wall thickness t (see Fig. 1), a repaired section with a length Lru (m) is marked, based on condition (1).

• where LRK is the total length of the repair structure that satisfies the condition (2)

• where LD is the length in meters of the defect to be repaired along the pipe axis;

LВ is the length in meters of the defect overlap by the repair structure along the pipe axis on each side of the defect.

The value of LV in meters must satisfy condition (3).

Table 1 (see Appendix 1) shows the values of LV according to this method for the most common pipeline diameters.

After marking, the repaired section of the pipeline 1, including the surface of the defect 2, is cleaned of earth, insulation, corrosion residues and other contaminants with a margin of about 100 mm on each side of the boundaries of the repair structure proposed for installation with a length LRK. Further, the surface of the repaired area is prepared to the first degree of cleaning according to GOST 9.402-2004 (or St 3 according to ISO 8501). Then the cleaned surface of the pipe is dedusted, for example, with a damp rag, dried and degreased with acetone, after which it is treated with a rust converter, which also acts as a primer. After complete drying of the treated surface, the cavity of defect 2 is filled with a fast-hardening polymer paste to a level of +0.5 mm to the level of the surface of a defect-free pipe. After that, without waiting for the complete hardening of the filling paste, within the limits of the length of the repair structure LRK, a polymeric adhesive composition is applied to the prepared section of the pipeline with a thin uniform layer and the internal composite sleeve 3 is mounted so that its horizontal joint 8 is located on the opposite side of the defect. Then, a polymer adhesive composition is applied on the surface of the mounted inner sleeve 3 in a thin even layer, and the outer composite sleeve 4 is mounted so that its horizontal joint 9 is located on the opposite side of the horizontal joint of the inner composite sleeve 8. Immediately after mounting the outer composite sleeve 4, on top of a composite coupling 5 is mounted on it, consisting of two half-couplings connected to each other in the circumference of the pipe on one side with the help of a hinge 7, and on the other - with a coupling screw 6. As a result of tightening the coupling screw 6 with a calibrated tightening force, carried out by a torque wrench, the coupling 5 tightly presses the composite bushings 3 and 4 to the surface of the repaired section of the pipeline 1, compressing it from the outside, creating a uniform external contact effect on the pipe with a value commensurate with the impact on the pipeline wall from the inside, created by the product pumped through the pipeline, which is under operating pressure ion. In this case, the resulting annular impact on the wall of the defective pipeline in the area of installation of the repair structure will be reduced to zero. In addition, a repair structure with a length LRK mounted on a defective section of the pipeline also removes longitudinal stresses from it. Thus, the repaired section is removed from the stress-strain state, which leads to the prevention of further development of the existing defect 2 and the formation of new defects. Reinforcing the wall of the repaired section of the pipeline by thickening its wall by gluing on it first the inner composite sleeve 3, and then on top of it the outer composite sleeve 4 with their compression due to the installation of composite couplings 5 returns the repaired section of the pipeline 1 to the state of a defect-free pipe and restores the original structural strength of the pipeline by the fireless method and without changing the pumping modes.

The second variant of the proposed method - the repair of external non-through defects at welded joints of pipeline sections and in their near-weld zones - is carried out as follows.

The boundaries of the repaired section of the pipeline are marked (see Fig. 2), LRU, based on condition (1) so that the welded joint is its axis of symmetry.

The surface of the repaired section of the pipeline 1, including the surface of the defect located on the reinforcement of the welded joint 10, or in its near-weld zone, is cleaned of earth, insulation, corrosion residues and other contaminants with a margin of about 100 mm on each side of the boundaries of the repair structure prepared for installation in length LRK. Then the surface of the repaired area is prepared to the first degree of cleaning according to GOST 9.402-2004 (or St 3 according to ISO 8501). Further, the cleaned surface of the pipe is dedusted, for example, with a damp rag, dried and degreased with acetone, after which it is treated with a rust converter, which also acts as a primer. After complete drying of the treated surface, the cavity of the defect of the welded joint is filled, as well as the selection for the welded joint 11 on the inner surface of the inner composite sleeve 3 with a section size a*b, where a is the width +5 mm and b is the height +2 mm of the reinforcement of the weld joint according to the regulatory documentation for the repaired pipeline, with quick-hardening polymer paste flush + 0.5 mm to the surface level without sampling. After that, without waiting for the filling paste to harden, within the limits of the length of the repair structure LRK, a polymeric adhesive composition is applied to the prepared section of the pipeline with a thin uniform layer, and the internal composite sleeve 3 is mounted with a sample filled with paste under the joint 2a on the welded joint 2. Then, on the surface of the mounted internal bushing 3, an external composite bushing 4 and a shrinkable composite sleeve 5 are mounted according to the technology indicated in the first method.

Also, as in the first method, a repair structure with a length LRK, mounted on a pipeline section with a defect in a welded joint, relieves both circumferential and longitudinal stresses from it, which leads to the prevention of further development of an existing defect in a welded joint and prevents the formation of new ones, which in turn compartment with reinforcement of the wall of the defective section of the pipeline by thickening it by gluing composite bushings 3 and 4 in two layers, restores the structural strength of the repaired section of the pipeline by a fireless method and without changing the pumping modes.

The third version of the proposed method is a fireless repair of pipeline sections with installations protruding above the pipe surface with a thickness not exceeding the nominal wall thickness and a length along the axis of not more than 0.9 m, without changing the pumping modes, using one repair structure - is carried out as follows.

The boundaries of the repaired section of the pipeline are marked (see Fig. 3), LRU, based on condition (1) so that the protruding installation 12 falls in the middle of the internal composite sleeve 3. Then, the boundaries of the protruding installation 12 are transferred to the outer surface of the composite sleeve 3 and a sample is made the area of the sleeve, repeating the shape of the installation, with a margin for the width of the welds with which it is welded to the pipe.

The surface of the repaired section of the pipeline 1, including the surface of the installation 12 protruding above it and the welds with which it is welded to the pipe, is cleaned of earth, insulation, corrosion residues and other contaminants with a margin of about 100 mm on each side of the boundaries of the repair structure prepared for installation in length LRK and then cleaned to the first degree of cleaning in accordance with GOST 9.402-2004 (or St 3 according to ISO 8501) by any available method. Further, the cleaned surface of the pipe is dedusted, dried, degreased with acetone and treated with a rust converter, as in the first and second methods. After complete drying of the treated surface, within the limits of the length of the repair structure LRK, a polymeric adhesive composition is applied to the prepared section of the pipeline with a thin uniform layer, and the internal composite sleeve 3 is installed with a pre-prepared sample under the installation 12 protruding above the pipeline surface. After that, the gaps between the installation are filled 12 and the borders of the sample under it in the inner composite sleeve 3, and also the thickness of the installation 12 is aligned with the thickness of the inner sleeve 3, with a quick-hardening polymer paste flush +0.5 mm to the surface level of the sleeve without sampling. Further, without waiting for the complete hardening of the leveling paste, a polymer adhesive composition is applied to the entire outer surface of the inner composite sleeve 2 in a thin uniform layer, and the external composite sleeve 4 and the composite screed sleeve 5 are mounted according to the technology indicated in the first method.

Also, as in the first and second methods, a repair structure with a length LRK mounted on a pipeline section with an installation protruding above its surface relieves both circumferential and longitudinal stresses from it, which leads to the prevention of defect formation in the repaired section, which, coupled with strengthening the walls of the defective section of the pipeline by thickening it by gluing composite bushings 3 and 4, restores the structural strength of the repaired section of the pipeline by a fireless method and without changing the pumping modes.

The fourth version of the proposed method - the repair of external non-through defects with a length along the pipeline axis of more than 0.9 m without changing the pumping modes, using several repair structures - is carried out as follows.

According to the proposed method, for the repair of defects in pipelines with a length of more than 0.9 m along the axis of the pipeline, several successively installed basic repair structures are required, therefore, the marking of the boundaries of the repaired section of the pipeline (see Fig. 4) LRU is carried out based on condition (1) so that the total length of the repair structure was not less than the value of LRK, calculated from expression (4):

LB is the length of the base repair structure in meters;

n is the number of basic repair structures required to repair a pipeline section with defects with a total length in meters LD, which is the distance along the pipe axis from the outer boundaries of the extreme defects in the repaired section determined from (5) (see Fig. 4), i.e. :

where LВ is the length, measured in meters, of covering the defect with the repair structure along the axis of the pipe on each side of the defect, which must satisfy condition (3).

The number of basic repair structures n required to repair a defective section of a pipeline with a length LD is obtained after rounding up to an integer value calculated by formula (6)

So, for example, for a pipeline from a pipe 325x8 mm (0.325x0.008 m), the overhang length, taking into account condition (3), is LV = 0.05 m (see Table 1). If we assume that the length of the base repair structure LB is 1 m, then to repair a defect with a length of LD = 2.3 m, you will need basic repair structures in the amount of n pieces, which is calculated according to (6) n = (2 * 0.05 + 2 ,3) / 1 = 2.4. After rounding up to an integer n ≈ 3 (pcs.).

According to the proposed method, the repair structure with a length of LRC, in addition to the inner and outer composite bushings, includes composite turnbuckles with a length of LM = 0.167 m in the amount of k pieces, installed over the outer composite bushings with an interval of Lp at a distance from the edges of the repair structure equal to Lp / 2 (see Fig. 4):

- when repairing defects with length LD ≤ 0.9 (m), LP = LM = 0.167 (m), LP/2=LM /2=0.167/2=0.084 (m); k=3n (pcs.); (7)

- when repairing defects with a length of LD > 0.9 (m), LP = 1.25LM = 0.208 (m), LP / 2 = 0.208 / 2 = 0.104 (m); k = 3n - 1 (pcs.). (8)

With the interval between the sleeves and the distance to the edges of the repair structure according to provision (8), the vertical joints of the base repair structures will always fall under the composite sleeves, which is a prerequisite for their structural relative position (see Fig. 4).

For all options, except for the third, the proposed method is applicable for repairing internal non-through defects in pipelines, provided that their technical condition is controlled by means of in-line diagnostics. If an internal defect is located on the pipe body outside the heat-affected zone of the welded joint of pipeline sections, its position is transferred to the outer surface of the pipeline and the first variant of the proposed method is applied. The operation of filling the defect with composite paste is excluded in this case. In the event that an internal defect is located at a vertical welded joint, or in its heat-affected zone, its position is also transferred to the outer surface of the pipeline and the second variant of the proposed method is applied. If there are internal defects in the section of the pipeline that is supposed to be repaired using the fourth variant of the proposed method, then their position is transferred to the outer surface of the pipeline and repairs are carried out in the same manner as for external defects, excluding the operation of filling defects with a fast-hardening composite paste. .

At the same time, in any of the options for repairing internal defects, magnetic markers are used, which are installed in front of the repair structure along the product with an orientation of 12 hours at a distance of no more than 0.5 meters from it. Magnetic markers are used to fix the location of the repaired internal defect at a distance of the pipeline for monitoring, using in-line diagnostics, its development beyond the limits of the repair structure.

According to all variants of the proposed method, internal composite bushings are installed when the filling composite paste is still in an uncured, deformable state, to ensure tight and continuous contact between the filled defect and the composite bushing, so that the load transfer from the defective section of the pipeline to the repair structure strengthening it occurs without losses.

Also, for all variants of the proposed method, after the completion of the installation work, all sinuses, gaps, etc. on the repair structure, as well as the places of its transition to the pipe body, for the purpose of sealing, are carefully covered with filling paste, after which the external insulation of the repaired area is restored over the installed repair structure with an overlap on both sides of it on the existing insulation, observing the standard technology of its application.

When repairing pipelines by the proposed method, cutting and/or alignment with the surface of the pipe of longitudinal welds is not required, as is required, using methods from the technical level.

The proposed method is applicable for the repair of external and internal defects of any length of pipelines from spiral-seam and shell pipes, which are difficult or impossible to repair using methods from the technical level.

For the manufacture of composite bushings, turnbuckles and rod-like parts, such reinforced polymers are used as: fiberglass; basalt plastic; carbon fiber; a mixture of basalt, glass, carbon fiber based on epoxy, polyester, organosilicon resins, polyethylene, polypropylene, polystyrene, polychloride, polyamide, polycarbonate, polytetrafluoroethylene, textolite, etc. The specified parts of the repair structures are made by pressing, vacuuming, winding the bundle, impregnation under pressure. At the same time, composite bushings are made elastically deformed: internal - under the outer diameter of the repaired pipeline; external - under the outer diameter of the repaired pipeline, taking into account the internal composite bushing glued to it. Elastic deformation of composite bushings under the specified diameters allows them to self-fix, after removing the stretching force from them, when mounted in the circumference of the pipe.

Composite polymerizing paste is used as a quick-hardening filler and adhesive composition.

All variants of the proposed method for fire-free repair of defective sections of pipelines without changing the pumping regimes have been repeatedly tested, have shown their industrial applicability and high efficiency by optimizing the cost of repair structures, expanding the seasonal framework for repairs, reducing its time and cost of organizational and technical measures for its implementation.

Appendix 1.

Claims (11)

1. The method of fireless repair without changing the modes of pumping non-through external mechanical and corrosion defects of linear sections with a structurally even outer surface of pipelines, which consists in preparing the surface of the repaired section, dedusting, removing moisture, degreasing with acetone, treating with a rust converter acting as a primer, filling the defect cavity fast-hardening composite paste, applying a thin uniform layer of polymer adhesive to the prepared area and mounting a full-encompassing composite repair structure on it, characterized in that the inner composite sleeve having a smooth inner and outer surface is first glued, then over the inner composite sleeve, overlapping the horizontal or vertical joint of the inner sleeve, an outer composite sleeve having a smooth inner and outer surface is glued onto a thin uniform layer of adhesive composition, on top of which a st hard composite couplings, consisting of two half-couplings, connected to each other on one side by hinges, and on the other hand, one per coupling by coupling screws. 2. The method according to claim 1, characterized in that the inner composite bushing has a thickness commensurate with the nominal thickness of the pipe wall along the axis LRK, which is determined by the formula LRK = LD + 2LВ, where LВ is the defect overlap length along the pipe axis, satisfying condition LВ ≥ 0.5√Dt ≥ 0.05 m, where D is the outer diameter, and t is the wall thickness of the repaired pipeline, and rounding up to the values LRK = 0.333 m, LRK = 0.667 m, or LRK = 1 m, then on top of the inner composite sleeve, overlapping the horizontal joint of the inner sleeve, on a thin uniform layer of adhesive composition, an outer composite sleeve having a smooth inner and outer surface is glued with a thickness commensurate with the nominal thickness of the wall of the pipeline under repair, on top of which they are mounted with a thickness commensurate with the wall thickness of the pipeline under repair and the length LM, calculated from the expression LM = 0.167LB, where LB is the length of the base repair structure, at a distance from the outer boundaries of the repair instructions equal to 0.5LM, with an interval equal to LM, in the amount of k pieces, calculated from the expression k = 3n, where n = LRK / LB, composite couplings, consisting of two half-couplings connected to each other on one side by hinges, and on the other hand, one per coupling with coupling screws, twisted with a calibrated force. 3. The method according to claim 1, characterized in that, for the repair of non-through external defects at the welded joints of pipeline sections and in their near-weld zones, internal composite bushings are used with a thickness commensurate with the nominal wall thickness of the pipeline being repaired with a sample for strengthening the welded joint on them internal surface with a sectional size a*b, where a is the width +5 mm and b is the height +2 mm of the reinforcement of the welded joint according to the regulatory documentation for the repaired pipeline. 4. The method according to claim 1, characterized in that, for repairing a pipeline section with an installation protruding above the pipe surface with a thickness not exceeding the thickness of the internal composite sleeve, an internal composite sleeve is used with a sample under the installation protruding above the pipe surface, followed by filling the gaps between the installation and the boundaries of the sample under it in the inner composite sleeve and the alignment of the thickness of the installation with the thickness of the inner sleeve with quick-hardening composite paste flush + 0.5 mm to the level of the outer surface of the inner sleeve without a sample. 5. The method according to claim 1, characterized in that, for the repair of non-through external defects with a length along the axis of the pipeline LD > 0.9 m, from the base repair structures with a length LB, a repair structure with a length LRK is made, calculated by the formula LRK = nLB, where n - the number of basic repair structures, with internal composite bushings for repairing defects in sections with a structurally even surface, for repairing defects at welded joints of pipeline sections, as well as in their near-weld zones, and / or for repairing sections with installations protruding above the surface of the pipeline, which installed in such a way that the outer composite bushings cover both horizontal and vertical joints of the inner composite bushings with the length LM, determined from the expression LM = 0.167LB, and the shrinkable composite sleeves in the amount of k, calculated by the formula k = 3n – 1, where n is the number base repair structures in the repair structure composed of them, obtained after rounding up to an integer th number of the value calculated by the formula n = (2LВ + LD)/LБ, where LВ is the defect overlap length along the pipe axis, satisfying the condition LВ ≥ 0.58√Dt ≥ 0.05 m, where D is the outer diameter, and t - the wall thickness of the repaired pipeline, were installed, overlapping the vertical joints of the external composite bushings, with an interval of LP in meters, equal to LP = 1.25LM, at a distance from the outer edges of the repair structure, equal to 0.5LP. 6. The method according to p. 1, characterized in that, when repairing non-through defects on the inner surface of flat sections of the repaired pipeline LD ≤ 0.9 m, as well as internal defects at welded joints and in their near-weld zones, the position of defects is transferred to the outer surface of the repaired pipeline, the operation of filling defects with a fast-hardening composite paste is excluded and employees are used to fix the location of the repaired internal defect at a distance of the pipeline for monitoring, using in-line diagnostics, its development beyond the repair structure, magnetic markers that are installed in front of the repair structure along the product flow with orientation at 12 o'clock at a distance of no more than 0.5 meters from it. 7. The method according to claim 5, characterized in that, when repairing non-through defects on the inner surface of structurally flat sections of the repaired pipeline LD > 0.9 m, as well as internal defects at welded joints and in their near-weld zones, the position of defects is transferred to the outer the surface of the pipeline being repaired, the operation of filling defects with a fast-hardening composite paste is excluded and employees are used to fix the location of the repaired internal defect at a distance of the pipeline for monitoring, using in-line diagnostics, its development beyond the repair structure, magnetic markers that are installed in front of the repair structure along the product flow with an orientation at 12 o'clock at a distance of no more than 0.5 meters from it. 8. The method according to claim 1, characterized in that the composite bushings are made elastically deformed to the diameter of the pipeline being repaired and they are installed when the filling composite paste is in an uncured, deformable state, to ensure tight and continuous contact between the defective section of the pipeline and the composite bushings, so that the transfer of the load from it to the reinforcing repair structure occurs without loss. 9. The method according to claim 5, characterized in that the composite bushings are made elastically deformed to the diameter of the repaired pipeline and they are installed when the filling composite paste is in an uncured, deformable state, to ensure tight and continuous contact between the defective section of the pipeline and the composite bushings, so that the transfer of the load from it to the reinforcing repair structure occurs without loss. 10. The method according to claim 1, characterized in that the same composite paste is used as a filling fast-hardening composite paste and a polymer adhesive composition. 11. The method according to p. 5, characterized in that the same composite paste is used as a filling fast-hardening composite paste and a polymer adhesive composition.

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