Reinforcing and maintaining device for non-stop conveying metal pipeline

Abstract

The utility model discloses a reinforcing and maintaining device for a non-stop conveying metal pipeline, which is used for maintaining a damaged running pipeline and is particularly suitable for reinforcing and maintaining a long-distance conveying pipeline. The device comprises a sleeve surrounding the periphery of a running pipeline, the two ends of the sleeve are connected with concentric and different-diameter plugging rings respectively, the large-diameter ends of the plugging rings are connected with the sleeve, the small-diameter ends of the plugging rings are connected with the running pipeline, and the sleeve is formed by welding two half sleeves with the same radius in pairs. And the plugging ring is formed by welding two same plugging semi-rings in pairs. A sleeve form is adopted for reinforcement and maintenance, an isolation space is formed at a damaged part of an operation pipeline, the damaged part of the metal pipeline is prevented from being continuously damaged or corroded due to external influence, and a welding sequence and a welding direction of a radial welding seam and a longitudinal welding seam of a semi-prefabricated sleeve and a circumferential welding seam of a plugging semi-ring and the operation pipeline are set; welding stress and welding deformation are effectively controlled, and safe operation of the pipeline is guaranteed.

Description

Technical Field

[0001] The utility model relates to the field of metal pipeline operation and maintenance engineering. Specifically, it relates to a device for reinforcing and repairing an operating pipeline when there is a large area of wall thickness thinning or a long-length damage in the pipeline during the operation of a non-stop metal pipeline, and is particularly applicable to the reinforcement and maintenance project of long-distance pipelines. Background Art

[0002] As the metal pipeline operates for a long time, there are phenomena of large-area wall thickness thinning or long-length damage. However, in the case where the pipeline cannot be shut down in the short term, in order to ensure the safe operation of the pipeline, it must be repaired. The existing pressure plugging technologies and the method of using steel plate patch welding in China cannot meet the repair requirements in these situations. Currently, the pressure plugging technology only plugs the leakage point or repairs a small area of damage, and the machining is complex and time-consuming. The commonly used method of covering and welding with a steel plate requires processing the arc of the steel plate and controlling the gap between its arc and the metal pipeline. If the gap is too large, the welding current will be large, which is likely to cause welding edge biting defects, and in severe cases, it will burn through and cause accidents.

[0003] CN117847338A discloses a pressure-on and online non-stop rapid repair and plugging device for pipelines, including a sleeve clamp for plugging the outer wall of the pipeline; the sleeve clamp includes an upper shell and a lower shell; wherein the upper shell and the lower shell are detachably spliced to form a sealing shell for plugging the leakage point of the pipeline; glue injection holes communicating with the sealing shell are respectively opened on the upper shell and the lower shell. However, this patent relies on filling sealant to bond with the pipeline to achieve reinforcement. The bond between the sealant and the metal pipeline will age and debond with the change of time and temperature, and gaps will soon appear, resulting in air leakage. Summary of the Utility Model

[0004] Aiming at the problems existing in the prior art, the utility model provides a reinforcing and repairing device and method for non-stop metal pipelines, which is safe and reliable in on-site operation, has a short repair time, not only meets the pressure-bearing strength of the conveying pipeline but also effectively controls the welding stress and pipeline deformation, ensures the safe operation of the conveying pipeline, avoids leakage and continuous corrosion of the conveying pipeline. The utility model changes the previous repair structure and welding method, reduces the welding stress, and is applicable to the repair of non-stop pipelines with long-length damage or large-area wall thickness thinning of metal pipelines.

[0005] According to an embodiment of the utility model, a reinforcing and repairing device for non-stop metal pipelines is provided, which includes a casing surrounding the periphery of the operating pipeline. Both ends of the casing are respectively connected with concentrically reduced-diameter plugging rings (i.e., truncated cone cylinders). The large-diameter end of the plugging ring is connected with the casing, and the small-diameter end of the plugging ring is connected with the operating pipeline. The casing is formed by butt-welding two half-casings with the same radius, and the plugging ring is formed by butt-welding two identical half-plugging rings. The two plugging rings are respectively arranged on both sides of the damage position of the operating pipeline.

[0006] Further, the casing is welded to the sealing ring, and the sealing ring is welded to the outer surface of the operating pipeline. The wall thickness of the casing is the same as that of the operating pipeline. It is classified according to the pipeline model. The diameter of the casing is two or three levels larger than the diameter of the operating pipeline (for example, for a DN100 pipeline, two levels larger is DN150, and three levels larger is DN175). The materials of the casing and the sealing ring are the same as those of the operating pipeline. The length of the casing is greater than the damaged length of the operating pipeline, such as 400 - 1000 mm larger, preferably 300 - 500 mm larger.

[0007] Further, the inner diameter of the small-diameter end of the sealing ring is slightly larger than the outer diameter of the operating pipeline, such as 1.6 - 6 mm larger, preferably about 3 mm or 4 mm. The difference between the inner diameter of the small-diameter end of the sealing ring and the outer diameter of the operating pipeline is twice the weld gap. The wall thickness of the sealing ring is 1 - 5 mm larger than the wall thickness of the operating pipeline, preferably about 2 - 4 mm, such as about 3 mm.

[0008] Further, the half casing includes semi-circular transverse surfaces at both ends and a longitudinal surface connecting the two transverse surfaces. The transverse surfaces form a first double-sided groove with a fifth blunt edge, and the longitudinal surface forms a first external groove with a first blunt edge. When the longitudinal surfaces of the two half casings are butt-welded, the two opposite first external grooves form a first V-groove. The angle of the first external groove can be, for example, 30° ± 5°, preferably 30°. The angle of the first double-sided groove can be, for example, 30° ± 5°, preferably about 30°. The angle range of the first V-groove is 50° - 70°, preferably about 60°. The widths of the first blunt edge and the fifth blunt edge can be, for example, 1 - 4 mm, preferably 2 - 3 mm.

[0009] Further, the sealing half-ring includes a small-ring end face provided at the small-diameter end, a large-ring end face provided at the large-diameter end, and a radial surface connecting the small-ring end face and the large-ring end face. The small-ring end face forms a second external groove with a second blunt edge, the large-ring end face forms a second double-sided groove with a third blunt edge, and the radial surface forms a third external groove with a fourth blunt edge. The widths of the second blunt edge, the third blunt edge, and the fourth blunt edge can be, for example, 1 - 4 mm, preferably 2 - 3 mm respectively. The angle of the second external groove can be, for example, 60° ± 5°, preferably about 60°. The angle of the second double-sided groove can be, for example, 30° ± 5°, preferably about 30°. The angle of the third external groove can be, for example, 30° ± 5°, preferably about 30°. When the radial surfaces of the two sealing half-rings are butt-welded, the two opposite third external grooves form a second V-groove. When the second double-sided groove of the sealing half-ring is welded to the first double-sided groove of the half casing, an X-groove is formed.

[0010] According to another embodiment of the present invention, a method for reinforcing and repairing a metal pipeline without shutting down the flow is provided, which includes the following steps:

[0011] (1)Calculate the cutting dimensions of the casing and the sealing ring and prepare the half-casing and the half-sealing ring;

[0012] (2)Machine the weld grooves of the half-casing and the half-sealing ring;

[0013] (3)Assemble and weld the half-casing and the half-sealing ring into a semi-precast casing;

[0014] (4)Weld the two semi-precast casings to the outer side of the damaged operating pipeline.

[0015] Furthermore, in step (1), before preparing the half-casing, select the material: select a metal pipe of the same type as the operating metal pipeline as the casing. The diameter of the casing is two or three levels larger than the diameter of the operating pipeline, and its thickness is the same as the wall thickness of the operating pipeline.

[0016] Before preparing the half-sealing ring, select the material: select a concentric reducer of the same type as the operating pipeline as the sealing ring. Its thickness is 1-5 mm larger than the wall thickness of the operating pipeline, preferably 3-4 mm.

[0017] In step (1), cut the half-casing: The length of the casing is 400-1000 mm larger than the damaged length of the operating pipeline, preferably 300-500 mm for cutting. Then, symmetrically mark the casing along the longitudinal direction and divide it into two halves, and cut it into two identical half-casings.

[0018] In step (1), cut the half-sealing ring: The difference between the inner diameter of the small-diameter end of the sealing ring and the outer diameter of the operating pipeline is twice the weld gap. Among them, the weld gap is preferably 0.8-3 mm, usually 2 mm. The inner diameter of the large-diameter end of the sealing ring is the same as the inner diameter of the casing. The wall thickness of the sealing ring is 1-5 mm larger than the wall thickness of the operating pipeline, preferably 3-4 mm. Then, cut the sealing ring into two half-sealing rings with the same radius.

[0019] Furthermore, in step (2), the longitudinal surfaces of the two half-casings are machined into a single-sided first outer groove. The angle of the first outer groove is 30°±5°, preferably about 30°, and the first root face is 2-3 mm; the transverse surfaces of the two half-casings are machined into a first double-sided groove. The angle of the first double-sided groove is 30°±5°, preferably about 30°, and the width of the fifth root face is 2-3 mm.

[0020] On the large-ring end face of the plugging half-ring, a second double-sided bevel with a third blunt edge is cut and polished. The angle of the second double-sided bevel can be, for example, 30° ± 5°, preferably about 30°. The third blunt edge is 1 - 4 mm, preferably 2 - 3 mm, which is convenient for complete penetration of the root pass in double-sided welding and easy root cleaning. The small-ring end face of the plugging half-ring is machined into a single-sided second external bevel with a second blunt edge. The angle of the second external bevel can be, for example, 60° ± 5°, preferably about 60°. The second blunt edge is 1 - 4 mm, preferably 2 - 3 mm. The radial faces of the two plugging half-rings are machined into a single-sided third external bevel with a fourth blunt edge. The angle of the third external bevel can be, for example, 30° ± 5°, preferably about 30°. The width of the fourth blunt edge is 1 - 4 mm, preferably 2 - 3 mm.

[0021] Further, in step (3), the two ends of the half casing are respectively paired and butt-welded with the plugging half-ring to form a semi-precast casing. The plugging half-ring and the half casing are kept coaxial. The large-diameter end of the plugging half-ring faces the end of the half casing. Tungsten inert gas (TIG) welding is used for backing welding, and manual arc welding is used for filling and surfacing. Non-destructive inspection is carried out on the weld between the plugging half-ring and the half casing, and the semi-precast casing is completed.

[0022] Further, in step (4), two semi-precast casings are used to enclose the operating pipeline after being paired. The opposite half casings form a casing surrounding the operating pipeline, and the opposite plugging half-rings form a plugging ring surrounding the operating pipeline. Before the semi-precast casing and the operating pipeline are paired and welded, the damaged operating pipeline is processed. The radial straight weld between the radial faces of the two plugging half-rings is tack-welded, then the two longitudinal welds between the longitudinal faces of the half casings are tack-welded, and finally the circumferential weld between the small-diameter end of the plugging half-ring and the operating pipeline is welded.

[0023] With the reinforcement and repair process of the present utility model, a closed space is formed at the damaged position of the casing and the operating pipeline, isolating external erosion and preventing the pipeline from further corrosion. And the casing structure meets the pressure-bearing strength of the pipeline operation. The reinforcement process of the present utility model clarifies the construction sequence and step methods, effectively controls welding stress and deformation, and ensures the safe operation of the conveying pipeline.

[0024] The above device and method have the following beneficial effects:

[0025] 1. By using the reinforcement and repair device of the present utility model, the problems of large-area wall thickness reduction or long-length damage of metal pipelines during non-stop operation are solved, and the safe operation of the pipeline after non-stop repair can be ensured.

[0026] 2. By adopting the form of casing for reinforcement and repair, an isolation space is formed at the damaged part of the operating pipeline, preventing the damaged part of the metal pipeline from being further damaged or corroded by external influence.

[0027] 3. The reinforcement and repair device of the present utility model is welded to the operating pipeline through the sealing rings arranged at both ends of the sleeve. The connection position between the reinforcement and repair device and the operating pipeline is only the sealing ring parts at both ends, solving the problem of large-area welding with the operating pipeline in the past. The metal properties of the operating pipeline are maintained, the welding amount with the metal pipeline is reduced, and the danger caused by the pressure welding of the pipeline without shutdown is reduced;

[0028] 4. By setting the welding sequence and welding direction of the radial weld, longitudinal weld of the semi-precast sleeve and the circumferential weld of the sealing half-ring and the operating pipeline, the welding stress and welding deformation are effectively controlled, and the safe operation of the pipeline is guaranteed;

[0029] 5. The semi-precast sleeve is obtained by connecting the semi-sleeve and the sealing half-ring. After the two semi-precast sleeves are enclosed, they are connected to the operating pipeline. The whole process is simple and easy to operate, simplifies the welding process, reduces the working difficulty, reduces the workload of welders, and improves the work efficiency;

[0030] 6. A complete set of construction technology for the reinforcement of metal pipelines without shutdown is formed and applied in the operation and detection project of long-distance natural gas pipelines, providing reference and guidance for the repair of metal pipelines with large-area wall thickness reduction or long-length damage without shutdown. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 FIG. is a schematic structural diagram of a reinforcement and repair device for non-stop metal pipelines of the present utility model.

[0032] Figure 2 FIG. is a front view of the semi-sleeve.

[0033] Figure 3 FIG. is a side view of the semi-sleeve.

[0034] Figure 4 FIG. is a perspective view of the semi-sleeve.

[0035] Figure 5 FIG. is Figure 4 a sectional perspective view taken along the A-A direction of

[0036] Figure 6 FIG. is a front view of the sealing half-ring.

[0037] Figure 7 FIG. is Figure 6 a groove schematic diagram at position I in

[0038] Figure 8 FIG. is Figure 6 a groove schematic diagram at position II in

[0039] Figure 9 FIG. is Figure 6 a groove schematic diagram at position III in

[0040] Figure 10 Stereogram of the plugging half-ring.

[0041] Figure 11 is Figure 10 Stereogram of the sectional view in the B-B direction of

[0042] Figure 12 Schematic diagram of the welding of the radial straight weld of the plugging ring.

[0043] Figure 13 Schematic diagram of the welding of the longitudinal weld of the casing.

[0044] Reference numerals:

[0045] 1 - Operating pipeline,

[0046] 2 - Casing, 20 - Half casing, 201 - Longitudinal surface, 2011 - First blunt edge, 2012 - First external groove, 202 - Transverse surface, 2021 - Fifth blunt edge, 2022 - First double-sided groove,

[0047] 3 - Plugging ring, 30 - Plugging half-ring, 301 - Large-diameter end, 302 - Small-diameter end, 303 - Small-ring end face, 3031 - Second blunt edge, 3032 - Second external groove, 304 - Large-ring end face, 3041 - Third blunt edge, 3042 - Second double-sided groove, 305 - Radial surface, 3051 - Fourth blunt edge, 3052 - Third external groove. Detailed implementation manner

[0048] The present invention will be further described below in conjunction with the drawings and embodiments.

[0049] As Figure 1-11 shown, the present invention provides a reinforcement and repair device for non-stop metal pipelines, which includes a casing 2 surrounding the periphery of the operating pipeline 1, and plugging rings 3 with concentric different diameters are respectively connected to both ends of the casing 2. The large-diameter end 301 of the plugging ring 3 is connected to the casing 2, and the small-diameter end 302 of the plugging ring 3 is connected to the operating pipeline 1. The casing 2 is formed by butt-welding two half casings 20 with the same radius, and the plugging ring 3 is formed by butt-welding two identical plugging half-rings 30. The two plugging rings 3 are respectively arranged on both sides of the damaged position of the operating pipeline 1. In specific applications, since the casing 2 surrounds the periphery of the operating pipeline 1 and the plugging rings 3 are connected to both sides of the damaged position of the operating pipeline 1, the casing 2 forms an isolation space for the damaged position, preventing the continuous damage of the damaged position of the operating pipeline 1.

[0050] The casing 2 is welded to the sealing ring 3, and the sealing ring 3 is welded to the outer surface of the operating pipeline 1. The wall thickness of the casing 2 is the same as that of the operating pipeline 1. It is classified according to the pipeline model. The diameter of the casing 2 is two or three levels larger than that of the operating pipeline 1. The materials of the casing 2 and the sealing ring 3 are the same as those of the operating pipeline 1. The length of the casing 2 is greater than the damaged length of the operating pipeline 1, for example, 400 - 1000 mm larger, preferably 300 - 500 mm larger.

[0051] The inner diameter of the small-diameter end 302 of the sealing ring 3 is slightly larger than the outer diameter of the operating pipeline 1, for example, 1.6 - 6 mm larger, further 2.0 - 4.0 mm, preferably about 4 mm. The difference between the inner diameter of the small-diameter end 302 of the sealing ring 3 and the outer diameter of the operating pipeline 1 is twice the weld gap. The wall thickness of the sealing ring 3 is 1 - 5 mm larger than the wall thickness of the operating pipeline 1, preferably 3 - 4 mm. In specific applications, the inner diameter of the small-diameter end 302 of the sealing ring 3 is larger than the outer diameter of the operating pipeline 1 to retain the weld gap between the small-diameter end 302 of the sealing ring 3 and the operating pipeline 1 and ensure the welding quality.

[0052] The half-casing 20 includes semi-circular transverse surfaces 202 at both ends and a longitudinal surface 201 connecting the two transverse surfaces 202. The transverse surface 202 forms a first double-sided groove 2022 with a fifth blunt edge 2021, and the longitudinal surface 201 forms a first outer groove 2012 with a first blunt edge 2011. When the longitudinal surfaces 201 of the two half-casings 20 are assembled and welded, the two opposite first outer grooves 2012 form a first V-groove. The angle of the first outer groove 2012 can be, for example, 30° ± 5°, preferably about 30°. The angle of the first double-sided groove 2022 can be, for example, 30° ± 5°, preferably about 30°. The angle range of the first V-groove is 50° - 70°, preferably about 60°. The widths of the first blunt edge 2011 and the fifth blunt edge 2021 can be, for example, 1 - 4 mm, preferably 2 - 3 mm, for example, 2 ± 0.5 mm. In specific applications, the longitudinal surface 201 forms a first outer groove 2012 with a first blunt edge 2011, and the width of the first blunt edge 2011 can be, for example, 1 - 4 mm, preferably 2 - 3 mm. When the longitudinal surfaces 201 of the two half-casings 20 are assembled and welded, the two opposite first outer grooves 2012 form a first V-groove, and the angle range of the first V-groove is 50° - 70°, preferably about 60°, to improve the filling and forming properties of the weld.

[0053] The plugging half-ring 30 includes a small-ring end face 303 disposed at the small-diameter end 302, a large-ring end face 304 disposed at the large-diameter end 301, and a radial face 305 connecting the small-ring end face 303 and the large-ring end face 304. The small-ring end face 303 forms a second external groove 3032 with a second blunt edge 3031. The large-ring end face 304 forms a second double-sided groove 3042 with a third blunt edge 3041. The radial face 305 forms a third external groove 3052 with a fourth blunt edge 3051. The widths of the second blunt edge 3031, the third blunt edge 3041, and the fourth blunt edge 3051 can be, for example, 1 - 4 mm respectively, preferably 2 - 3 mm. The width of the fifth blunt edge 2021 and the third blunt edge 3041 are preferably equal. The angle of the second external groove 3032 can be, for example, 60° ± 5°, preferably about 60°. The angle of the second double-sided groove 3042 can be, for example, 30° ± 5°, preferably about 30°. The angle of the third external groove 3052 can be, for example, 30° ± 5°, preferably about 30°. When the radial faces 305 of the two plugging half-rings 30 are butt-welded, the two opposite third external grooves 3052 form a second V-groove, and the angle range of the second V-groove is 50° - 70°, preferably about 60°. When the second double-sided groove 3042 of the plugging half-ring 30 is welded to the first double-sided groove 2022 of the half casing 20, an X-groove is formed, and the angle range of the X-groove is 50° - 70°, preferably about 60°. In specific applications, the widths of the second blunt edge 3031, the third blunt edge 3041, and the fourth blunt edge 3051 can be, for example, 1 - 4 mm respectively, preferably 2 - 3 mm, reducing stress concentration during the welding process and reducing the risk of crack generation in the weld. The angle of the second external groove 3032 can be, for example, 60° ± 5°, preferably about 60°. The angle of the second double-sided groove 3042 can be, for example, 30° ± 5°, preferably about 30°. The angle of the third external groove 3052 can be, for example, 30° ± 5°, preferably about 30°. The angle settings of the first double-sided groove 2022, the first external groove 2012, the second external groove 3032, the second double-sided groove 3042, and the third external groove 3052 enable welders to easily control the welding current, avoid incomplete penetration and porosity. On the other hand, it reduces the metal filling amount, reduces the welding line energy, and avoids large welding stress or deformation.

[0054] The present utility model further provides a reinforcement repair method for a metal pipeline without shutting down the flow, which includes the following steps:

[0055] (1) Calculate the blanking dimensions of the casing and the plugging ring and prepare the half casing and the plugging half-ring;

[0056] (2) Machine the weld grooves of the half casing and the plugging half-ring;

[0057] (3) Assemble and weld the half casing and the plugging half-ring into a semi-precast casing;

[0058] (4) Weld two semi-precast sleeves to the outside of the damaged operating pipeline.

[0059] In step (1), material selection before preparing the semi-sleeve: Select a metal pipe material of the same type as the operating metal pipe as the sleeve. The diameter of the sleeve is two or three levels larger than the diameter of the operating pipeline, and its thickness is the same as the wall thickness of the operating pipeline.

[0060] Material selection before preparing the plugging half-ring: Select a concentric reducing pipe of the same type as the operating pipeline as the plugging ring. Its thickness is 1 - 5 mm larger than the wall thickness of the operating pipeline, preferably 3 - 4 mm.

[0061] In step (1), cutting the semi-sleeve: Cut the sleeve with a length greater than the damaged length of the operating pipeline by 400 - 1000 mm, preferably 300 - 500 mm. Then, symmetrically mark the sleeve along the longitudinal direction and divide it into two halves, cutting it into two identical semi-sleeves. Since the sleeve materials are different, different cutting methods and tools are used. For example, carbon steel materials are cut by gas cutting, and stainless steel materials are cut by plasma cutting.

[0062] In step (1), cutting the plugging half-ring: The difference between the inner diameter of the small-diameter end of the plugging ring and the outer diameter of the operating pipeline is twice the weld gap. The weld gap is preferably 0.8 - 3 mm, usually 2 mm. The inner diameter of the large-diameter end of the plugging ring is the same as the inner diameter of the sleeve. The wall thickness of the plugging ring is 1 - 5 mm larger than the wall thickness of the operating pipeline, preferably 3 - 4 mm. Then, cut the plugging ring into two plugging half-rings with the same radius. Since the metal pipe materials are different, different cutting methods and tools are used. For example, carbon steel materials are cut by gas cutting, and stainless steel materials are cut by plasma cutting.

[0063] In step (2), process the longitudinal surfaces of the two semi-sleeves into a single-sided first external groove. The angle of the first external groove is 30° ± 5°, preferably about 30°, and the first root face is 2 - 3 mm; process the transverse surfaces of the two semi-sleeves into a first double-sided groove. The angle of the first double-sided groove is 30° ± 5°, preferably about 30°, and the width of the fifth root face is 2 - 3 mm.

[0064] Cut and grind the large-ring end face of the plugging half-ring to form a second double-sided groove with a third root face. The angle of the second double-sided groove can be, for example, 30° ± 5°, preferably about 30°, and the third root face is 1 - 4 mm, preferably 2 - 3 mm, which is convenient for complete penetration of the root pass in double-sided welding and easy root cleaning; process the small-ring end face of the plugging half-ring into a single-sided second external groove with a second root face. The angle of the second external groove can be, for example, 60° ± 5°, preferably about 60°, and the second root face is 1 - 4 mm, preferably 2 - 3 mm; process the radial surfaces of the two plugging half-rings into a single-sided third external groove with a fourth root face. The angle of the third external groove can be, for example, 30° ± 5°, preferably about 30°, and the width of the fourth root face is 1 - 4 mm, preferably 2 - 3 mm. The purpose is to ensure single-sided welding with double-sided formation.

[0065] In step (3), both ends of the half casing are fixedly connected to the butting joints of the plugging half rings to form a semi-precast casing. The plugging half rings are coaxial with the half casing. The large-diameter end of the plugging half ring faces the end of the half casing. The second double-sided groove of the plugging half ring and the first double-sided groove of the half casing form an X-shaped groove. Both sides of the weld are cleaned; the welding is carried out in layers. When welding, TIG welding is used for backing (that is, TIG welding is the first layer of welding. TIG welding for backing ensures the quality of the root weld, and the weld is uniform without pores), and manual arc welding is used for filling and surfacing (manual arc welding is the second layer and subsequent weld layers, ensuring a uniform weld height and improving the mechanical properties of the welded joint). The specific operation is as follows: First, weld the inner side weld of the plugging half ring and the half casing once, and then weld the outer side weld once. Weld alternately in sequence until the weld height is reached. After the weld cools naturally, measure the dimensions of the semi-precast casing, and conduct non-destructive inspection on the weld between the plugging half ring and the half casing. If it meets the specifications, it is qualified, and the semi-precast casing is completed.

[0066] In step (4), use two semi-precast casings to surround and butt the operating pipeline after being grouped. The opposite half casings form a casing surrounding the operating pipeline, and the opposite plugging half rings form a plugging ring surrounding the operating pipeline. Before the semi-precast casing and the operating pipeline are grouped and welded, deal with the damaged operating pipeline: Treat the anticorrosive layers at both ends of the damaged position of the operating pipeline according to the length of the semi-precast casing, measure and mark the welding position of the small-diameter end of the plugging half ring and the operating pipeline, and grind it to a metallic luster to ensure that the weld position is cleaned.

[0067] In step (4), the gap between the small-diameter end of the plugging half ring and the operating pipeline is maintained at 0.8 - 3 mm, preferably 2 mm. The third outer groove on the radial surface of the two opposite plugging half rings forms a second V-shaped groove. The longitudinal weld between the two half casings is placed in the horizontal direction. The first outer groove on the longitudinal surface of the two half casings forms a first V-shaped groove, and its gap is maintained at 2 - 3 mm. After the measurement is qualified, first tack weld the radial straight weld between the radial surfaces of the two plugging half rings, and then tack weld the two longitudinal welds between the longitudinal surfaces of the half casings. The fillet weld between the plugging ring and the operating pipeline is not tack welded temporarily.

[0068] In step (4), for all welds, TIG welding is used for backing, and manual arc welding is used for filling and surfacing, as Figure 12 shown. Specifically: First, weld the two radial straight welds of the plugging half ring. Two welders weld simultaneously from the inside to the outside to ensure that the plugging ring does not deform and the welding stress is small; after the appearance inspection of the radial straight weld of the plugging half ring is qualified, as Figure 13 shown, weld the longitudinal welds of the half casings. The two longitudinal welds are welded in the opposite direction simultaneously. Each layer of weld is welded in a segmented backstep manner to reduce the welding stress. The number of welding layers preferably meets the weld height; non-destructive testing is carried out on both the straight weld of the plugging ring and the longitudinal weld of the casing. If it meets the specification requirements, it is qualified.

[0069] In step (4), finally, the small-diameter end of the half-ring for welding and plugging is welded to the circumferential weld (i.e., fillet weld) of the operating pipeline. The argon arc welding is used for backing welding, and the manual arc welding is used for filling and surfacing. Specifically, two welders weld symmetrically at the same time, and multi-layer reverse welding is adopted, that is, the backing welding direction is from bottom to top, and the filling and surfacing are from top to bottom, so as to reduce the welding stress and deformation. After the weld cools down (usually 24 hours), non-destructive testing is carried out. If there are defects, repair treatment is carried out, and the same position cannot exceed twice. Example 1

[0070] For a certain high-pressure long-distance natural gas pipeline, the design pressure is 1.6 MPa and the operating pressure is 1.2 MPa. The steel pipe material of the operating pipeline is L245, and the specification is D406.4×8 mm (the outer diameter of the pipeline is 406.4 mm and the wall thickness is 8 mm). During the owner's inspection, it was found that the 3PE anti-corrosion layer of about 5 meters of a section of the pipeline at a certain ditch was severely damaged, and the metal surface layer had been corroded. Using a thickness gauge to detect, it was found that the wall thickness of this section of the pipeline was thinned to varying degrees, and it was necessary to carry out non-stop reinforcement and repair, and repair this section of the pipeline.

[0071] (1) Calculate the cutting dimensions of the casing and the plugging ring, and prepare the half-casing and the plugging half-ring for plugging the operating pipeline:

[0072] Selection of materials for the half-casing and the plugging half-ring: The same material L245 as the operating pipeline is selected for the casing. The casing pipe specification D508×8 mm is used as the cutting material for the half-casing; the concentric reducer specification DN500×DN400×9 mm is selected as the cutting material for the plugging half-ring.

[0073] Cutting of the half-casing and the plugging half-ring: The length of the casing is cut according to a length greater than the damaged length of the operating metal pipeline by 500 mm, and then the metal casing is divided into two halves by symmetrically scribing longitudinally, and it is cut into two identical half-casings.

[0074] According to the difference between the inner diameter of the small-diameter end of the plugging ring and the outer diameter of the operating pipeline being twice the weld gap, and the weld gap being 2 mm, the inner diameter of the small-diameter end of the plugging ring is obtained as D410.4 mm, and the outer diameter of the large-diameter end of the plugging ring is D508 mm, and then it is cut into two identical plugging half-rings.

[0075] (2) Process the weld grooves of the half-casing and the plugging half-ring

[0076] As Figure 2-11 shown, the longitudinal surfaces of the two half-casings are processed into a single-sided first outer groove, the first outer groove angle is 30°, the first root face is 2 mm, the transverse surfaces of the two half-casings are processed into a first double-sided groove, the angle of the first double-sided groove is 30°, and the width of the fifth root face is 2 mm.

[0077] The large-ring end face of the plugging half-ring is cut and polished to form a second double-sided bevel with a third blunt edge. The angle of the second double-sided bevel is 30°, and the third blunt edge is 2 mm, which is convenient for complete penetration of the root pass in double-sided welding and easy root cleaning; the small-ring end face of the plugging half-ring is machined into a single-sided second external bevel with a second blunt edge. The angle of the second external bevel is 60°, and the second blunt edge is 2 mm; the radial faces of the two plugging half-rings are machined into a single-sided third external bevel with a fourth blunt edge. The angle of the third external bevel is 30°, and the width of the fourth blunt edge is 2 mm. The purpose is to ensure single-sided welding with double-sided formation.

[0078] (3)The half casing and the plugging half-ring are welded into a semi-preformed casing;

[0079] The two ends of the half casing are respectively paired with the plugging half-ring at the butt joint points and fixed to form a semi-preformed casing. The plugging half-ring and the half casing are kept coaxial. The large-diameter end of the plugging half-ring faces the end of the half casing. The second double-sided bevel of the plugging half-ring and the first double-sided bevel of the half casing form an X-shaped bevel, and both sides of the weld are cleaned; during welding, argon arc welding is used for backing, and manual arc welding is used for filling and capping. The specific operation is as follows: First, weld the inner side weld of the plugging half-ring and the half casing once, and then weld the outer side weld once, and alternately weld in sequence to reach the weld height. After the weld cools naturally, the dimensions of the semi-preformed casing are inspected and measured, and the weld between the plugging half-ring and the half casing is inspected nondestructively. If it meets the specifications, it is qualified, and the semi-preformed casing is completed.

[0080] (4)The semi-preformed casing is paired and welded with the damaged operating pipeline.

[0081] Two semi-preformed casings are used to surround the operating pipeline after pairing. The opposite half casings form a casing surrounding the operating pipeline, and the opposite plugging half-rings form a plugging ring surrounding the operating pipeline. The anti-corrosion layers at both ends of the damaged position of the operating pipeline are processed according to the length of the semi-preformed casing. The small-diameter end of the plugging half-ring is measured, marked at the welding position with the operating pipeline, and polished to a metallic luster to ensure that the weld position is cleaned. The two semi-preformed casings are assembled with the operating pipeline. The gap between the small-diameter end of the plugging half-ring and the operating pipeline is kept at 2 mm. The third external bevels on the radial faces of the two opposite plugging half-rings form a second V-shaped bevel. The longitudinal weld between the two half casings is placed horizontally. The first external bevels on the longitudinal faces of the two half casings form a first V-shaped bevel, and the gap is kept at 2 mm. After the measurement is qualified, the radial straight weld between the two plugging half-rings and the two longitudinal welds between the half casings are tack-welded.

[0082] All welds are welded by using argon arc welding for backing and manual arc welding for filling and capping. The specific operation process is as follows: First, weld the two radial straight welds between the plugging half-rings (as Figure 12 shown), and the welding direction is from the inside to the outside. The two straight welds of each plugging half-ring are symmetrically welded by two welders at the same time. After the radial straight weld of the plugging half-ring is inspected and qualified, weld the longitudinal welds on both sides of the half casing, as shownFigure 13 For the two longitudinal welds, they must be welded simultaneously in opposite directions. For the longer weld, the segmental backstep welding method is adopted. The number of welding layers should meet the weld height requirement, and the appearance inspection should be qualified.

[0083] Finally, weld the circumferential fillet weld between the inner ring of the small-diameter end of the plugging half-ring and the operating pipeline. The argon arc welding is used for backing welding and the manual arc welding is used for filling and surfacing. Each plugging half-ring is welded symmetrically by two welders simultaneously. The first pass of welding (backing welding) is carried out from bottom to top, and the filling and surfacing welding is carried out from top to bottom to reduce the welding stress and deformation. After the weld cools down (usually 24 hours), the butt straight weld is inspected by flaw detection, and the fillet weld is inspected by coloring or ultrasonic inspection. If there are defects, repair them. The same position should not be repaired more than twice.

[0084] In summary, the on-site construction process steps are as follows: construction preparation → on-site investigation and measurement → material selection → calculation and cutting → cutting into pieces → bevel making → welding the plugging half-ring and the half casing to form a semi-precast casing → spot welding the radial straight-edge weld of the plugging half-ring → symmetrically and reversely welding the butt welds on both sides of the half casing → non-destructive testing of the welds → inspection and repair → symmetrically welding the inner ring of the plugging half-ring and the circumferential weld of the operating pipeline → ultrasonic testing of the fillet weld → surface anti-corrosion after passing the inspection → overall acceptance.

[0085] The preferred embodiments of the present invention have been described above. However, the above description is not for the purpose of limitation. Those of ordinary skill in the art can make targeted changes or modifications to the present invention without departing from the gist and scope of the present invention. The said changes or modifications should be included within the scope of the appended claims.

Claims

1. A reinforcement and maintenance device for non-stop metal pipelines, characterized in that: It includes a casing surrounding the periphery of a running pipeline, with concentric and different-diameter sealing rings connected to both ends of the casing respectively, the large-diameter end of the sealing ring is connected to the casing, and the small-diameter end of the sealing ring is connected to the running pipeline. The casing is formed by welding two half-casing groups with the same radius, and the sealing ring is formed by welding two identical sealing half-ring groups. The two sealing rings are respectively arranged on both sides of the damaged position of the running pipeline.

2. The reinforcement and repair device according to claim 1, characterized in that: The casing is connected to the plugging ring by welding, and the plugging ring is connected to the outer surface of the running pipeline by welding. The wall thickness of the casing is consistent with the wall thickness of the running pipeline. The diameter of the casing is two or three levels larger than the diameter of the running pipeline. The materials of the casing and the plugging ring are the same as that of the running pipeline. The length of the casing is greater than the damaged length of the running pipeline.

3. The reinforcement and repair device according to claim 2, characterized in that: The inner diameter of the small diameter end of the plugging ring is larger than the outer diameter of the running pipe. The difference between the inner diameter of the small diameter end of the plugging ring and the outer diameter of the running pipe is twice the weld gap. The wall thickness of the plugging ring is 1-5mm larger than the wall thickness of the running pipe.

4. The reinforcement and repair device according to claim 3, characterized in that: The wall thickness of the plugging ring is 3-4mm greater than the wall thickness of the running pipe.

5. The reinforcement and repair device according to any one of claims 1 to 4, characterized in that: The half sleeve includes a semi-annular transverse surface located at both ends and a longitudinal surface connecting the two transverse surfaces. The transverse surface forms a first two-sided groove with a fifth blunt edge, and the longitudinal surface forms a first outer groove with a first blunt edge. When the longitudinal surfaces of the two half sleeves are butt-welded, the two opposite first outer grooves form a first V-shaped groove. The angles of the first outer groove and the first two-sided groove are 30°±5° respectively, and the widths of the first blunt edge and the fifth blunt edge are 1-4mm.

6. The reinforcement and repair device according to claim 5, characterized in that: The plugging half ring includes a small ring end face arranged at the small diameter end, a large ring end face arranged at the large diameter end and a radial face connecting the small ring end face and the large ring end face, the small ring end face forms a second outer groove with a second blunt edge, the large ring end face forms a second two-sided groove with a third blunt edge, the radial face forms a third outer groove with a fourth blunt edge, the widths of the second blunt edge, the third blunt edge and the fourth blunt edge are 1-4mm respectively, the angle of the second outer groove is 60°±5°, the angle of the second two-sided groove is 30°±5°, and the angle of the third outer groove is 30°±5°. When the radial faces of the two plugging half rings are butt welded, the two opposite third outer grooves form a second V-shaped groove, and the second two-sided groove of the plugging half ring is welded to the first two-sided groove of the half casing to form an X-shaped groove.

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