Exhaust self-recovery leveling polyethylene composite belt for bent pipe and mounting method of exhaust self-recovery leveling polyethylene composite belt

Abstract

The exhaust self-leveling polyethylene composite belt comprises a base material layer and a hot melt adhesive layer, a plurality of first exhaust grooves are rolled in the surface of one side of the base material layer, the surface of the other side of the base material layer is covered with the hot melt adhesive layer, and a plurality of second exhaust grooves are rolled in the surface of the side, away from the base material layer, of the hot melt adhesive layer; the base material layer and the pipeline are bonded through the hot melt adhesive layer, the multiple parallel second exhaust grooves formed in the hot melt adhesive layer at intervals are rolled in the hot melt adhesive layer, and the multiple parallel first exhaust grooves formed in the base material layer at intervals are rolled in the base material layer. Gas on the surface of a high-temperature pipeline is exhausted along with contraction of the exhaust grooves in the surface of the hot melt adhesive layer, when the composite belts are heated, the rolled exhaust grooves can generate a memory effect and slowly recover to a plane state along with heating temperature rise, and gas between the composite belts is exhausted along with re-flattening extrusion of the exhaust grooves. And finally, a high-strength anti-corrosion structure is formed on the surface of the pipeline.

Description

Technical Field

[0001] The present invention belongs to the technical field of anti-corrosion of oil and gas pipelines, and particularly relates to an exhaust self-restoring polyethylene composite tape for elbows and an installation method thereof. Background Art

[0002] In the oil and gas industry, the 3LPE anti-corrosion technology with high anti-corrosion quality is currently usually used to anti-corrode the straight pipe part in the pipeline main body. The 3LPE anti-corrosion technology is: the 3-layer structure anti-corrosion of spraying an FBE powder layer + an anti-corrosion adhesive layer + a polyethylene pipeline anti-corrosion material layer on the outside of the elbow; however, the elbow part in the pipeline main body accounts for 8-10%. Due to the special structure of the elbow part, only anti-corrosion measures with lower quality can be used to anti-corrode the elbow part at present. For example: only painting anti-corrosion coatings, heat shrinkable wrapping tapes, rubber and plastic anti-corrosion tapes, asphalt cold wrapping tapes and other anti-corrosion measures; the 3LPE anti-corrosion structure with high anti-corrosion quality can reach 45 years for the anti-corrosion life validity period of oil and gas pipelines, while the anti-corrosion technology with lower anti-corrosion quality generally has an anti-corrosion life validity period of 20-35 years for oil and gas pipelines. The two types of anti-corrosion measures make it impossible to uniformly benchmark the anti-corrosion life of the same oil and gas pipeline, and the technical integrity of the entire pipeline system cannot be achieved, resulting in the need to frequently conduct excavation or non-excavation pipeline corrosion assessment on the elbow parts with poor anti-corrosion measures during the actual pipeline transportation operation, enter the underground to detect the corrosion situation and the remaining life situation, and often face complex post-treatment problems such as suspending oil and gas transportation for anti-corrosion layer repair or elbow section node replacement. During the repair or replacement of the elbow after excavation, it is easy to cause relatively major safety accidents.

[0003] The back material and the adhesive layer of the traditional polyethylene composite tape for elbows both belong to the modified polyethylene system, and the material belongs to a relatively hard texture. Due to factors such as differences in working conditions, regional differences, differences in the proficiency of personnel operation, differences in prefabricated equipment manufacturers, and differences in the rigor of factory inspection and evaluation in the downstream prefabricated elbow anti-corrosion factory, after the composite tape is installed and wound and overlapped during production, the air between the layers of the composite tape and at the circumferential inner overlap cannot be completely removed, and air pockets appear under the anti-corrosion layer. It is difficult to completely eliminate. Due to the high air pocket rate of some products, they cannot meet the acceptance standards, resulting in problems such as rework, waste, and low production efficiency of the anti-corroded finished elbows. Especially, the probability of air pockets appearing in the multi-layer winding part of the inner arc of large-angle elbows is higher. This problem has caused many technical discussions at meetings of pipeline experts, industry insiders, and elbow anti-corrosion factories. The traditional polyethylene composite tape for elbows is researched, developed and upgraded to solve the technical problem of air pockets under the anti-corrosion layer of prefabricated elbows, so as to achieve the technical integrity of the entire pipeline system and reduce the safety hazards of excavating and repairing the anti-corrosion layer of oil and gas pipelines.

[0004] Therefore, an anti-corrosion material and process that can make the anti-corrosion quality at the elbow meet the standard of 3LPE anti-corrosion are needed, so that the elbows with a proportion of the pipeline main body reaching 8-10% meet the technical requirements of the 3LPE anti-corrosion structure with high anti-corrosion quality, thereby improving the service life of the elbows. Summary of the Invention

[0005] The object of the present invention is to provide an exhaust self-restoring polyethylene composite tape for elbows and its installation method, which can completely remove the air between layers and at the circumferential lap joint after the composite tape is installed and wound, prevent the occurrence of air pockets under the anti-corrosion layer, meet the acceptance standards, and achieve the purpose of improving the anti-corrosion effect on the pipeline.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] An exhaust self-restoring polyethylene composite tape for elbows includes a base material layer and a hot melt adhesive layer covering and connected to the base material layer. First exhaust grooves penetrating the width direction of the base material layer are arranged at intervals on the surface of the base material layer, and second exhaust grooves penetrating the width direction of the hot melt adhesive layer are arranged at intervals on the side of the hot melt adhesive layer away from the base material layer.

[0008] Preferably, the sizes of both the first exhaust groove and the second exhaust groove are 0.2 mm - 3 mm in width and 0.2 mm - 1 mm in depth.

[0009] Preferably, both ends of the side of the base material layer where the first exhaust groove is arranged are provided with inclined thinning edges.

[0010] Preferably, the inclination angle of the thinning edge is 20° to 60°.

[0011] Preferably, the total thickness of the base material layer and the hot melt adhesive layer is 1.5 mm - 3 mm.

[0012] An installation method of an exhaust self-restoring polyethylene composite tape for elbows includes the following steps:

[0013] S1: Perform heating pretreatment on the pipeline;

[0014] S2: Wind the exhaust self-restoring polyethylene composite tape for elbows on the pretreated pipeline;

[0015] S3: Make the composite tape shrink on the pipeline surface;

[0016] S4: Cool down.

[0017] Preferably, the operation method of winding the exhaust self - flattening polyethylene composite tape for bent pipes on the pre - treated pipeline is as follows: After the pipeline is sprayed with powder and reaches 170°C - 190°C, the exhaust self - flattening polyethylene composite tape for bent pipes is wound. When winding the composite tape, it is evenly wound from one end of the pipeline to the other end in a winding manner with an overlap ratio greater than or equal to 55%; during winding, the second exhaust groove of the hot - melt adhesive layer melts and flattens, squeezing the gas between the exhaust self - flattening polyethylene composite tape for bent pipes and the pipeline out from the second exhaust groove.

[0018] Preferably, the operation method of shrinking the exhaust self - flattening polyethylene composite tape for bent pipes on the pipeline surface is as follows: The pipeline wound with the exhaust self - flattening polyethylene composite tape for bent pipes is heated from the outside by a far - infrared heating ring to make the exhaust self - flattening polyethylene composite tape for bent pipes shrink. The first exhaust groove of the base material layer shrinks when heated, squeezing the gas between the exhaust self - flattening polyethylene composite tape for bent pipes and the exhaust self - flattening polyethylene composite tape out from the first exhaust groove, and finally the first exhaust groove is flattened by heat.

[0019] The present invention has achieved the following technical effects compared with the prior art:

[0020] 1) In the present invention, the base material layer is bonded to the pipeline through the hot - melt adhesive layer. Multiple parallel and spaced - apart second exhaust grooves are rolled on the hot - melt adhesive layer, and multiple parallel and spaced - apart first exhaust grooves are rolled on the base material layer. When the composite tape is wound on the pipeline surface, the gas on the surface of the high - temperature pipeline is discharged as the second exhaust groove on the surface of the hot - melt adhesive layer shrinks. When the composite tape is heated, the rolled second exhaust groove will produce a memory effect and slowly return to a flat state as the heating temperature rises. The gas between the composite tapes is squeezed out as the first exhaust groove flattens, and finally a high - strength anti - corrosion structure is formed on the pipeline surface.

[0021] 2) In the present invention, both ends of the base material layer of the composite tape on the side with the first exhaust groove are set as thinning edges. When the composite tape is wound on the pipeline surface in a winding manner with an overlap ratio greater than or equal to 55%, the thinning edges can reduce the gap between the composite tapes, so that the composite tape is more tightly bonded to the pipeline surface, further improving the anti - corrosion performance of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the following - described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 It is a schematic side - view structure diagram of the composite tape in the present invention.

[0024] Figure 2 Schematic diagram of the exhaust groove structure on the substrate layer of the composite tape in the present invention.

[0025] Figure 3 Schematic diagram of the exhaust groove structure on the hot melt adhesive layer of the composite tape in the present invention.

[0026] Wherein, 1. Substrate layer; 11. First exhaust groove; 12. Thinned edge; 2. Hot melt adhesive layer; 21. Second exhaust groove. Specific embodiments

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] The object of the present invention is to provide an exhaust self - restoring polyethylene composite tape for bent pipes and its installation method to achieve the purpose of improving the anti - corrosion effect on pipes.

[0029] To make the above - mentioned objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Embodiment 1:

[0031] The exhaust self - restoring polyethylene composite tape for bent pipes, such as Figure 1 , Figure 2 and Figure 3As shown, it includes a substrate layer 1 and a hot melt adhesive layer 2. The substrate layer 1 is preferably made of cross-linked polyethylene material; the hot melt adhesive layer 2 covers one side surface of the substrate layer 1. On the other side surface of the substrate layer 1, a number of parallel and spaced first exhaust grooves 11 are rolled. The first exhaust grooves 11 are of a linear structure. The first exhaust grooves 11 penetrate the width direction of the substrate layer 1. The upper and lower ends of the first exhaust grooves 11 extend to the two side edges of the substrate layer 1. At the upper and lower ends of the side of the substrate layer 1 where the first exhaust grooves 11 are provided, inclined thinning edges 12 are provided. The thickness of the thinning edges 12 on the substrate layer 1 is less than the thickness of the middle part thereof. The inclination angle of the thinning edges 12 on the substrate layer 1 relative to its surface is 40°; the cross-section of the first exhaust grooves 11 is a U-shaped groove structure. The width of the first exhaust grooves 11 is 1 mm, the depth of the first exhaust grooves 11 is 0.6 mm, and the spacing between the first exhaust grooves 11 is 10 mm; on the hot melt adhesive layer 2, second exhaust grooves 21 that are parallel and spaced are also rolled. The width of the second exhaust grooves 21 is also 1 mm, the depth of the second exhaust grooves 21 is 0.6 mm, and the spacing between the second exhaust grooves 21 is 10 mm. The second exhaust grooves 21 penetrate the width direction of the hot melt adhesive layer 2; the thickness of the exhaust self-restoring polyethylene composite tape for bent pipes is 2.15 mm, wherein the thickness of the substrate layer 1 is 1.5 mm and the thickness of the hot melt adhesive layer 2 is 0.65 mm. The width of the composite tape body is 120 mm, which is relatively narrow, enabling it to adapt to the bending points of the pipes. If the width of the exhaust self-restoring polyethylene composite tape for bent pipes is relatively wide, serious deformation will occur at the bending points of the pipes, affecting its winding effect and anti-corrosion effect.

[0032] When manufacturing the composite tape, a finished strip-shaped cross-linked polyethylene is fully coated with hot melt adhesive on one surface to make the composite tape body. After the hot melt adhesive solidifies, the first exhaust grooves 11 and the second exhaust grooves 21 are simultaneously rolled on both sides of the composite tape body through a rolling device. During rolling, a hot pressing method is used. The first exhaust grooves 11 with the same interval are rolled on one side of the base material layer 1, and the second exhaust grooves 21 with the same interval and the same size are rolled on one side of the hot melt adhesive layer 2; the cross-sections of the first exhaust grooves 11 and the second exhaust grooves 21 are both U-shaped groove structures. The U-shaped groove structure can make the bottoms of the first exhaust grooves 11 and the second exhaust grooves 21 have tension, prevent the composite tape from breaking at the bottom position of the first exhaust grooves 11 when winding the composite tape, and is conducive to the later flattening of the first exhaust grooves 11 and the second exhaust grooves 21; in addition, the hot rolling process enables the cross-linked polyethylene to generate a memory effect during heating, thereby producing a self-flattening effect during heating; if the first exhaust grooves 11 are processed by a traumatic grooving method, the self-flattening effect cannot be achieved, and there is no tension at the bottom of the first exhaust grooves 11, which easily causes the composite tape to break during the winding process of the composite tape; then, a grinding device is used to grind and thin the upper and lower edges on one side of the cross-linked polyethylene where the first exhaust grooves 11 are provided. The thinned edge 12 formed by grinding and thinning can effectively reduce the gap between the composite tapes when winding the pipeline later. When grinding and thinning the thinned edge 12, the thickness of the outermost side of the thinned edge 12 is less than the thickness between the bottom of the first exhaust grooves 11 and the other surface of the base material layer 1. Therefore, the two ends of the first exhaust grooves 11 gradually disappear at the position of the thinned edge 12.

[0033] Example 2:

[0034] The construction method of the exhaust self-flattening polyethylene composite tape for bent pipes includes the following steps:

[0035] S1: Perform heat pretreatment on the pipeline;

[0036] S2: Wind the composite tape on the pretreated pipeline;

[0037] S3: Make the composite tape shrink on the pipeline surface;

[0038] S4: Cool down.

[0039] When performing heat pretreatment on the pipeline, the pipeline is heated to 220°C - 230°C and then epoxy powder is sprayed, so that the epoxy powder melts and evenly covers on the pipeline surface. The epoxy powder can provide preliminary protection for the pipeline, and in addition, it can make the hot melt adhesive bond more firmly to the pipeline surface;

[0040] The specific operation method of winding the composite tape on the pre-treated pipeline is as follows: The winding operation of the composite tape is carried out after powder spraying when the temperature reaches 170°C - 190°C. During construction in summer, the surface temperature of the pipeline is controlled between 170°C - 175°C for winding the composite tape; during construction in winter, due to the low external temperature, to avoid the rapid cooling of the pipeline causing the hot melt adhesive to not melt, the surface temperature of the pipeline is controlled within the range of 185°C - 190°C for winding the composite tape during winter construction. When winding the composite tape, it is evenly wound from one end of the pipeline to the other end in a winding method with an overlap ratio greater than or equal to 55%, that is: the second layer of the composite tape presses part of the first layer of the composite tape, and the third layer of the composite tape presses part of the second layer of the composite tape while being able to tightly press the edge of the first layer of the composite tape under the second layer of the composite tape. At this time, the inclined structure of the thinning edge 12 plays an important role, which can greatly reduce the gap between the composite tapes. And because the thinning edges 12 are provided on both the upper and lower sides of the composite tape, the composite tape can be wound forward or backward, which is convenient for construction; in addition, setting the thinning edge 12 can make the protective layer on the surface of the pipeline smooth, so as to reduce the resistance generated when the pipeline creeps in the underground soil; when the composite tape contacts the high-temperature surface of the pipeline, the hot melt adhesive layer 2 melts and bonds the base material layer 1 on the surface of the pipeline. At the same time, as the hot melt adhesive layer 2 melts, the gas in the second exhaust groove 21 can be squeezed out as the exhaust groove 21 disappears, and the gas between the two composite tapes during the lap winding of the composite tapes will be squeezed into the first exhaust groove 11 of the base material layer 1. As the subsequent heating of the surface of the base material layer 1 causes it to shrink, the gas in the first exhaust groove 11 is squeezed out.

[0041] The specific operation method of shrinking the composite tape on the surface of the pipeline is as follows: The pipeline wound with the composite tape is heated from the outside by a far-infrared heating ring. The set temperature of the far-infrared heating ring is 220°C. The surface of the composite tape is evenly heated at a high temperature of 220°C to make the composite tape shrink. During the shrinkage process of the composite tape, the first exhaust groove 11 gradually flattens, and the gas between the composite tapes can be squeezed out from the first exhaust groove 11; due to the memory effect of the cross-linked polyethylene material, when it is heated, the memory effect appears, and the regular rolled exhaust groove 11 gradually returns to a flat state with heating. The existing composite tape surface does not have the first exhaust groove 11. During the winding process of the existing composite tape and the pipeline, the gas between the composite tapes cannot be discharged, resulting in bulging and deformation after the composite tape is wound, and the gas cannot be discharged, making the composite tape unable to fit with the pipeline or the lower composite tape, seriously affecting the anti-corrosion effect.

[0042] The specific cooling operation method is as follows: First, use a compressed air air-cooling device to air-cool the pipeline, so that the surface temperature of the pipeline wrapped with the composite tape is reduced to below 110 °C. Then, perform spray water-cooling. When performing spray water-cooling, it is first necessary to ensure that the surface temperature of the pipeline drops to below 110 °C before starting the water-cooling, so as to avoid the appearance of spot-like water traces on the surface of the composite tape; when performing spray water-cooling, form a water film around the pipeline to ensure synchronous circumferential cooling of the pipeline, reduce the circumferential distortion caused by local shrinkage of the composite tape, and then affect the appearance of the product. When the temperature is further reduced to 60 °C - 65 °C by spray water-cooling, hoist it offline.

[0043] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0044] In addition, in the description of the present invention, if terms such as "horizontal" and "vertical" appear, it does not mean that the components are required to be absolutely horizontal or hanging vertically, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0045] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, if the terms "set", "installed", "connected", "connected" are used, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0046] The above is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Any simple modification and equivalent change made to the above embodiments based on the technical essence of the present invention all fall within the protection scope of the present invention.

Claims

1. An exhaust self-restoring flat polyethylene composite tape for bent pipes, characterized in that, It includes a base material layer and a hot melt adhesive layer covering and connected to the base material layer. On the surface of the base material layer, first exhaust grooves penetrating the width direction of the base material layer are arranged at intervals. On the side of the hot melt adhesive layer away from the base material layer, second exhaust grooves penetrating the width direction of the hot melt adhesive layer are arranged at intervals.

2. The exhaust self-restoring flat polyethylene composite tape for bent pipes according to claim 1, wherein The sizes of both the first exhaust grooves and the second exhaust grooves are 0.2 mm - 3 mm in width and 0.2 mm - 1 mm in depth.

3. The exhaust self-restoring polyethylene composite tape for bent pipes according to claim 1, characterized in that, At both ends of the surface of the base material layer where the first exhaust grooves are arranged, inclined thinning edges are provided.

4. The exhaust self-restoring polyethylene composite tape for bent pipes according to claim 3, wherein, The inclination angle of the thinning edge is 20° to 60°.

5. The exhaust self-restoring polyethylene composite tape for bent pipes according to claim 3, wherein, The total thickness of the base material layer and the hot melt adhesive layer is 1.5 mm - 3 mm.

6. An installation method of an exhaust self - restoring flat polyethylene composite tape for bent pipes, characterized in that, When applied to the exhaust self - flattening polyethylene composite tape for bent pipes according to any one of claims 1 to 5, the following steps are included: S1: Conduct heat pretreatment on the pipe. S2: Wind the exhaust self - flattening polyethylene composite tape for bent pipes on the pretreated pipe. S3: Make the composite tape shrink on the pipe surface. S4: Cool down.

7. The installation method of the exhaust self-restoring polyethylene composite tape for bent pipes according to claim 6, characterized in that, The operation method of winding the exhaust self - flattening polyethylene composite tape for bent pipes on the pretreated pipe is as follows: When the pipe is sprayed with powder and reaches 170°C - 190°C, the winding operation of the exhaust self - flattening polyethylene composite tape for bent pipes is carried out. When winding the composite tape, it is evenly wound from one end of the pipe to the other end in a winding manner with a lap ratio greater than or equal to 55%; during winding, the second exhaust grooves of the hot melt adhesive layer melt and flatten, and the gas between the exhaust self - flattening polyethylene composite tape for bent pipes and the pipe is extruded from the second exhaust grooves.

8. The installation method of the exhaust self - restoring polyethylene composite tape for bent pipes according to claim 6, characterized in that, The operation method of making the exhaust self - flattening polyethylene composite tape for bent pipes shrink on the pipe surface is as follows: The pipe wound with the exhaust self - flattening polyethylene composite tape for bent pipes is heated from the outside by a far - infrared heating ring to make the exhaust self - flattening polyethylene composite tape for bent pipes shrink. The first exhaust grooves of the base material layer are heated and shrunk, and the gas between the exhaust self - flattening polyethylene composite tape for bent pipes and the exhaust self - flattening polyethylene composite tape for bent pipes is extruded from the first exhaust grooves, and finally the first exhaust grooves are heated and flattened.

Images