阅读说明：本技术 管道的补口方法 (Pipeline joint coating method ) 是由 窦宏强 邱劲 刘佳 王丽 苏卫峰 孔维维 张世梅 于 2020-05-14 设计创作，主要内容包括：本公开提供了一种管道的补口方法,属于油气管道领域,所述管道的补口方法包括：对补口位置进行预清理；对所述补口位置进行预热处理；对所述补口位置的金属部位进行喷砂处理；对所述补口位置的防腐层部位进行等离子体处理,对所述补口位置的防腐层部位进行接枝聚合处理；在所述补口位置安装热收缩带；对所述热收缩带进行烘烤。通过对管道防腐层进行等离子体轰击可显著提升热熔胶型热收缩带与防腐层部位之间的粘接强度。(The utility model provides a joint coating method of pipeline, which belongs to the field of oil gas pipeline, and comprises the following steps: pre-cleaning the repaired mouth; preheating the position of the repaired mouth; carrying out sand blasting treatment on the metal part at the repaired mouth position; carrying out plasma treatment on the anticorrosive layer part at the joint coating position, and carrying out graft polymerization treatment on the anticorrosive layer part at the joint coating position; installing a heat shrinkable tape at the repaired mouth position; and baking the heat shrinkable tape. The bonding strength between the hot melt adhesive type heat shrinkable tape and the anticorrosive layer part can be remarkably improved by carrying out plasma bombardment on the pipeline anticorrosive layer.)

1. A method for repairing a pipeline, comprising:

pre-cleaning the repaired mouth;

preheating the position of the repaired mouth;

carrying out sand blasting treatment on a metal part at the joint repairing position, wherein the metal part is a part which is not coated with anticorrosive paint at the joint repairing position;

carrying out plasma treatment on the anticorrosive coating part at the joint coating position, wherein the anticorrosive coating part is a part coated with anticorrosive paint on the joint coating position;

carrying out graft polymerization treatment on the anticorrosive layer part at the joint coating position;

installing a heat shrinkable tape at the repaired mouth position;

and baking the heat shrinkable tape.

2. A method of repairing a pipe according to claim 1, wherein said pre-cleaning of the repair site comprises:

cleaning dirt at the repaired mouth position and cleaning the defects at the repaired mouth position, wherein the defects comprise welding beading, burrs or edges and corners;

and a transition slope surface is arranged on the anticorrosive coating part and is positioned at the edge of the anticorrosive coating part close to the metal part at the joint coating position.

3. A method of repairing a pipe according to claim 1, wherein said preheating of said repairing position comprises:

and preheating the position of the repaired mouth by adopting a medium-frequency induction heater.

4. A method of repairing a pipe according to claim 1, wherein said blasting a metal portion of said repairing site, said metal portion being a portion of said repairing site not coated with an anticorrosive paint, comprises:

and performing sand blasting and rust removal on the metal part at the joint repairing position, so that the rust removal grade of the metal surface of the pipeline reaches Sa2.5 grade, and the dust degree grade at least reaches a second-grade quality grade.

5. A method for repairing a pipe according to claim 1, wherein said plasma treatment of the portion of the anticorrosive coating at the repairing position comprises:

cleaning a lap joint area of the anticorrosive layer, wherein the lap joint area of the anticorrosive layer is an area where the anticorrosive layer is used for installing the heat shrinkable tape;

and bombarding the lap joint area of the anticorrosive coating by adopting a plasma technology, so that a polar functional group is formed on the surface of the lap joint area of the anticorrosive coating.

6. A method of coating a pipe as claimed in claim 5, wherein said bombardment of the lap zone of said corrosion protection layer by means of plasma techniques comprises:

and bombarding the lap joint area of the anticorrosive coating by adopting low-temperature normal-pressure air plasma, wherein the processing voltage of the plasma is 175V, the processing speed is 4m/min, and the processing width is 100-150 mm.

7. A method for repairing a pipe according to claim 5, wherein said graft polymerization of the anticorrosive coating portion at the repairing position comprises:

respectively coating solvent-free epoxy primer on the lap joint area of the anticorrosive coating at the repaired mouth position and the metal part, wherein the thickness of the solvent-free epoxy paint on the lap joint area of the anticorrosive coating is kept between 50 and 150 mu m, and the thickness of the solvent-free epoxy paint on the metal part is kept not less than 150 mu m.

8. A method of jointing a pipe as claimed in claim 1, wherein said installing a heat-shrinkable tape at said jointing position comprises:

wrapping the heat shrinkable tapes at the position of the repaired mouth in an end-to-end way;

the head and tail parts of the heat shrinkable tape are fixed together through fixing sheets.

9. A method of patching a pipe as claimed in claim 1, wherein said baking the heat-shrinkable tape comprises:

baking the heat-shrinkable tape by an infrared heater to shrink and mold the heat-shrinkable tape;

and heating the heat shrinkable tape subjected to shrinkage molding, and keeping the surface temperature of the heat shrinkable tape at 120-180 ℃ for 10-25 min.

10. The method of claim 1, wherein after said baking of said heat-shrinkable tape, said method of repairing a pipe comprises:

and compacting the bulge between the heat shrinkable tape and the repaired opening position.

Technical Field

The disclosure belongs to the field of oil and gas pipelines, and particularly relates to a method for repairing a pipeline opening.

Background

The long-distance oil and gas pipeline is formed by connecting a plurality of steel pipelines, and an anticorrosive coating is arranged outside the pipeline. In order to facilitate welding in the construction process, a part of the pipeline welding part is not provided with an anticorrosive coating and is directly exposed outside, and the joint coating anticorrosive treatment is required to be carried out on the part of the pipeline welding part. The common method for the joint coating anticorrosion treatment is realized by installing a polyethylene heat-shrinkable tape at the joint coating position.

In the related art, when a polyethylene heat-shrinkable tape is installed, the heat-shrinkable tape is usually connected end to end and wrapped at a joint coating position, and the joint coating anticorrosion treatment of a pipeline circumferential weld is completed by utilizing certain bonding force and sealing capacity generated between hot melt adhesive of the heat-shrinkable tape and a bonded surface. In the process of joint coating anticorrosion treatment, the surface (joint coating position) coated by the hot melt adhesive is not provided with a metal part of an anticorrosion layer, and needs to be overlapped with the anticorrosion layer. In order to increase the effective adhesion and the effective sealing between the thermal contraction band and the anticorrosive layer, the propane gas is generally combusted to heat and oxidize the anticorrosive layer overlapped with the thermal contraction band, and the steel wire brush is used to perform galling treatment on the anticorrosive layer after being heated and softened.

However, when the method is adopted to heat and oxidize the anticorrosive coating, flame can directly contact with the anticorrosive coating, and the surface of the anticorrosive coating can be ablated and burnt by careless operation, so that the effect of increasing the bonding force cannot be achieved, and the anticorrosive coating is damaged. The steel wire brush napping treatment directly damages the structural integrity of the anticorrosive coating, and napping can fragment the anticorrosive coating on the surface layer, so that a plurality of completely stripped and broken particles are generated on the surface of the anticorrosive coating, and even if the hot melt adhesive and the particles form good infiltration and are mutually embedded, the heat shrinkable tape and the anticorrosive coating cannot be effectively bonded.

Disclosure of Invention

The embodiment of the disclosure provides a method for repairing a pipeline, which can enhance the bonding degree between a heat shrinkable tape and the pipeline. The technical scheme is as follows:

the embodiment of the disclosure provides a method for repairing a pipeline, which comprises the following steps:

pre-cleaning the repaired mouth;

preheating the position of the repaired mouth;

carrying out sand blasting treatment on a metal part at the joint repairing position, wherein the metal part is a part which is not coated with anticorrosive paint at the joint repairing position;

carrying out plasma treatment on the anticorrosive coating part at the joint coating position, wherein the anticorrosive coating part is a part coated with anticorrosive paint on the joint coating position;

carrying out graft polymerization treatment on the anticorrosive layer part at the joint coating position;

installing a heat shrinkable tape at the repaired mouth position;

and baking the heat shrinkable tape.

In an implementation manner of the present disclosure, the pre-cleaning of the repaired mouth position includes:

cleaning dirt at the repaired mouth position and cleaning the defects at the repaired mouth position, wherein the defects comprise welding beading, burrs or edges and corners;

and a transition slope surface is arranged on the anticorrosive coating, and the transition slope surface is positioned at the edge of the anticorrosive coating, which is close to the metal part at the joint coating position.

In another implementation manner of the present disclosure, the performing a preheating process on the repaired mouth position includes:

and preheating the position of the repaired mouth by adopting a medium-frequency induction heater.

In another implementation manner of the present disclosure, the sand blasting a metal portion of the repaired site, where the metal portion is not coated with an anticorrosive paint, includes:

and performing sand blasting and rust removal on the metal part at the joint repairing position, so that the rust removal grade of the metal surface of the pipeline reaches Sa2.5 grade, and the dust degree grade at least reaches a second-grade quality grade.

In another implementation manner of the present disclosure, the performing plasma treatment on the anticorrosive coating portion of the repaired site includes:

cleaning a lap joint area of the anticorrosive layer, wherein the lap joint area of the anticorrosive layer is an area on the anticorrosive layer for mounting the heat shrinkable tape;

and bombarding the lap joint area of the anticorrosive coating by adopting a plasma technology, so that a polar functional group is formed on the surface of the lap joint area of the anticorrosive coating.

In another implementation manner of the present disclosure, the bombarding the lap zone of the anti-corrosion layer by using the plasma technology includes:

and bombarding the lap joint area of the anticorrosive coating by adopting low-temperature normal-pressure air plasma, wherein the processing voltage of the plasma is 175V, the processing speed is 4m/min, and the processing width is 100-150 mm.

In another implementation manner of the present disclosure, the performing a graft polymerization treatment on the anticorrosive coating portion at the joint repair position includes:

respectively coating solvent-free epoxy primer on the lap joint area of the anticorrosive coating at the repaired mouth position and the metal part, wherein the thickness of the solvent-free epoxy paint on the lap joint area of the anticorrosive coating is kept between 50 and 150 mu m, and the thickness of the solvent-free epoxy paint on the metal part is kept not less than 150 mu m.

In yet another implementation of the present disclosure, the installing a heat-shrinkable tape at the repaired site includes:

wrapping the heat shrinkable tapes at the position of the repaired mouth in an end-to-end way;

the head and tail parts of the heat shrinkable tape are fixed together through fixing sheets.

In yet another implementation of the present disclosure, the baking the heat shrinkable tape includes:

baking the heat-shrinkable tape by an infrared heater to shrink and mold the heat-shrinkable tape;

and heating the heat shrinkable tape subjected to shrinkage molding, and keeping the surface temperature of the heat shrinkable tape at 120-180 ℃ for 10-25 min.

In yet another implementation of the present disclosure, after the baking the heat-shrinkable tape, the method of patching a pipe includes:

and compacting the bulge between the heat shrinkable tape and the repaired opening position.

The technical scheme provided by the embodiment of the disclosure has the following beneficial effects:

when the pipeline joint coating method provided by the embodiment of the disclosure is used for joint coating operation on a pipeline, the surface of the joint coating position is firstly pre-cleaned, so that the cleanliness of the joint coating position can be improved, and the influence on the bonding strength between the pipeline and a heat shrinkable tape due to the existence of dirt and defects is avoided. And then, preheating the position of the repaired mouth, so that the surface of the pipeline is dry, and the bonding effect is prevented from being influenced by the existence of moisture. And then, carrying out sand blasting treatment on the metal part at the joint coating position, and effectively removing rust impurities of the pipeline through the sand blasting treatment so as to further improve the cleanliness of the pipeline. And then, carrying out plasma treatment on the anticorrosive layer at the joint coating position, treating the surface of the anticorrosive layer by using a plasma technology, on one hand, not generating substantial damage to the anticorrosive layer, on the other hand, generating active polar groups on the surface of the anticorrosive layer of the pipeline under the bombardment of high-energy ions, then carrying out graft polymerization treatment on the polar groups generated on the surface of the anticorrosive layer of the pipeline at the joint coating position, thus not only eliminating the timeliness defect of the plasma treatment, but also forming chemical bonding with higher bonding strength and better bonding effect between the anticorrosive layer of the joint coating and the surface of the pipeline after the graft polymerization treatment, finally installing a heat-shrinkable tape, and baking the heat-shrinkable tape, thus easily completing the joint coating operation.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

FIG. 1 is a schematic view of a piping structure provided by an embodiment of the present disclosure;

FIG. 2 is a flow chart of a method for patching a pipeline provided by an embodiment of the present disclosure;

fig. 3 is a flowchart of another method for repairing a pipe joint according to an embodiment of the present disclosure.

Detailed Description

To make the objects, technical solutions and advantages of the present disclosure more apparent, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

The embodiment of the disclosure provides a method for repairing a pipeline, which is suitable for performing joint repairing and corrosion prevention operation on the pipeline. The position of the repaired mouth of the pipeline is firstly described with reference to fig. 1:

as shown in fig. 1, the joint repairing position of the pipeline has a metal part 1 and an anticorrosive coating part 2, and the metal part 1 is a bare steel joint position reserved at two ends of the pipeline when the pipeline is manufactured, that is, a part which is not coated with anticorrosive paint at the joint repairing position. Anticorrosive coating position 2 is the position that coats on the repaired mouth position and has been scribbled anticorrosive paint, and anticorrosive coating position 2 and metal part 1 are close to be arranged, and the anticorrosive coating is used for preventing that the pipeline from taking place the corruption destruction.

Fig. 2 is a flow chart of the corrosion prevention method, and in combination with fig. 2, the method for repairing the opening of the pipeline comprises the following steps:

s201: and pre-cleaning the repaired mouth position.

In the implementation mode, the surface of the repaired mouth position is pre-cleaned, so that dirt and defects can be effectively removed, and the bonding strength between the repaired mouth position and the thermal contraction belt is stronger in the subsequent steps.

S202: and carrying out preheating treatment on the repaired mouth position.

In the above implementation mode, the position of the repaired mouth is preheated, the moisture on the surface of the pipeline can be removed, and the repaired mouth effect is prevented from being influenced by the moisture.

S203: and carrying out sand blasting treatment on the metal part at the joint coating position, wherein the metal part is a part which is not coated with the anticorrosive paint at the joint coating position.

In the implementation mode, the metal part at the joint coating position is subjected to sand blasting treatment, so that impurities such as rust at the joint coating position can be effectively removed, and the cleanliness of the joint coating position is further ensured.

S204: and carrying out plasma treatment on the anticorrosive coating part at the joint coating position, wherein the anticorrosive coating part is coated with anticorrosive paint at the joint coating position.

In the implementation mode, the surface of the pipeline anticorrosive layer is subjected to plasma treatment, so that polar functional groups can be formed on the surface of the pipeline anticorrosive layer, and the adhesion between the pipeline anticorrosive layer and the heat shrinkable tape is further increased.

S205: and carrying out graft polymerization treatment on the anticorrosive layer part at the repaired mouth position.

In the implementation mode, after the position of the to-be-repaired opening is subjected to polarization treatment on the pipeline anticorrosive coating part by adopting a plasma technology, the graft polymerization treatment is carried out, so that the polar functional group generated in the pipeline anticorrosive coating part can be stably and permanently fixed on the surface of the pipeline anticorrosive coating part, and the surface of the pipeline anticorrosive coating part is always kept in a stable polarization state.

S206: and installing a heat shrinkable tape at the repaired mouth position.

In the implementation mode, the thermal contraction belt is installed to perform joint coating on the to-be-repaired opening of the pipeline, so that the pipeline is prevented from being corroded and damaged.

S207: and baking the heat shrinkable tape.

When the pipeline joint coating method provided by the embodiment of the disclosure is used for joint coating operation on a pipeline, the surface of the joint coating position is firstly pre-cleaned, so that the cleanliness of the joint coating position can be improved, and the influence on the bonding strength between the pipeline and a heat shrinkable tape due to the existence of dirt and defects is avoided. And then, preheating the position of the repaired mouth, so that the surface of the pipeline is dry, and the bonding effect is prevented from being influenced by the existence of moisture. And then, carrying out sand blasting treatment on the metal part at the joint coating position, and effectively removing rust impurities of the pipeline through the sand blasting treatment so as to further improve the cleanliness of the pipeline. And then, carrying out plasma treatment on the anticorrosive layer at the joint coating position, treating the surface of the anticorrosive layer by using a plasma technology, on one hand, not generating substantial damage to the anticorrosive layer, on the other hand, generating active polar groups on the surface of the anticorrosive layer of the pipeline under the bombardment of high-energy ions, then carrying out graft polymerization treatment on the polar groups generated on the surface of the anticorrosive layer of the pipeline at the joint coating position, thus not only eliminating the timeliness defect of the plasma treatment, but also forming chemical bonding with higher bonding strength and better bonding effect between the anticorrosive layer of the joint coating and the surface of the pipeline after the graft polymerization treatment, finally installing a heat-shrinkable tape, and baking the heat-shrinkable tape, thus easily completing the joint coating operation.

Fig. 3 is another pipeline opening repairing method provided in this embodiment, and as shown in fig. 3, the pipeline opening repairing method includes:

s301: and pre-cleaning the repaired mouth position.

Step 301 is implemented by:

firstly, cleaning dirt at the position of the repaired mouth and cleaning the defects at the position of the repaired mouth, wherein the defects comprise welding beading, burrs or edges and corners.

In the implementation mode, the dirt at the position of the repaired mouth is cleaned in a wiping or blowing mode. The dirt can be oil, grease, dust and other pollutants attached to the surfaces of the metal part and the anticorrosive layer part. Meanwhile, the defects at the position of the repaired mouth are cleaned in a scraping and polishing mode. The defects can be welding beading, burrs, edges and corners and the like on the surface of the metal part, and raised edges, cracks and the like on the anticorrosive coating part.

Through the cleaning, the surfaces of the metal part of the pipeline and the surface of the anticorrosive coating part can be finally ensured to be clean, and preparation is made for subsequent joint coating anticorrosive treatment.

And then, arranging a transition slope surface on the anticorrosive coating part, wherein the transition slope surface is positioned at the edge of the anticorrosive coating part close to the metal part at the joint coating position.

In the above implementation manner, by setting the anticorrosive layer portion to be in the transition slope shape, it can be ensured that the liquid applied to the anticorrosive layer portion is effectively and uniformly arranged between the anticorrosive layer portion and the metal portion when the subsequent graft polymerization is performed (step S305), and furthermore, a gap between the anticorrosive layer and the heat shrinkable tape can be avoided when the heat shrinkable tape is mounted subsequently, so as to improve the bonding strength between the anticorrosive layer and the heat shrinkable tape.

Exemplarily, the angle of inclination a of the transition ramp is not larger than 30 ° (see fig. 1).

In the implementation mode, the inclination angle of the transition slope surface is limited, so that smooth transition between the anticorrosive layer part and the metal part can be ensured, and the follow-up smooth transition can be ensured when liquid is coated or a thermal contraction belt is wrapped.

S302: and carrying out preheating treatment on the repaired mouth position.

Step 302 may be implemented by:

and preheating the position of the repaired mouth by adopting a medium-frequency induction heater.

In above-mentioned implementation, when heating the repaired mouth position through intermediate frequency induction heater, not only can make things convenient for operation control, can guarantee the effect of getting rid of pipeline surface moisture again simultaneously to prepare for follow-up sand blasting. When the environmental temperature is low or the humidity of air is high, even if a sand blasting rust removal mode is adopted, products after rust removal are easy to adhere to the surface of the pipeline, and the cleanliness of the surface of the pipeline is affected.

For example, when the gap repairing position is preheated by adopting the medium-frequency induction heater, the temperature of the gap repairing position can be controlled to be 50-80 ℃.

In above-mentioned implementation, through reasonable control heating range, can improve heating efficiency on the one hand, guarantee the degree of drying on pipeline surface, can not cause the damage to the anticorrosive coating at repaired mouth position because of the high temperature again simultaneously.

S303: and carrying out sand blasting treatment on the metal part at the repaired mouth position.

Step 303 may be implemented by:

the metal surface of the pipeline reaches Sa2.5 grade of rust removal grade and the dust degree grade at least reaches second grade quality grade by carrying out sand blasting rust removal on the metal part at the joint coating position.

In the implementation mode, the joint coating position is subjected to sand blasting for rust removal, so that the cleanliness of the surface of the pipeline can be obviously improved, the contact area between the solvent-free epoxy primer coated in the subsequent step and the pipeline can be increased by improving the cleanliness of the surface of the pipeline, the bonding force between the solvent-free epoxy primer and the pipeline is further improved, and the bonding strength between the heat shrinkable tape and the pipeline is finally improved.

In the derusting process, the surface anchor line depth of the pipeline after sand blasting is 40-90 mu m.

It should be noted that the pipeline surface rust removal grade reaching the level of Sa2.5 or above is a requirement for the treatment depth of the metal base material of the pipeline, and the pipeline dust degree reaching the quality grade of two or above is a requirement for whether dust and impurities adhere to the pipeline surface, and how much dust and impurities adhere to the pipeline surface.

S304: and carrying out plasma treatment on the anticorrosive coating part at the repaired mouth position.

Step 304 is implemented by:

firstly, cleaning the lap joint area of the anticorrosive coating, wherein the lap joint area of the anticorrosive coating is an area for installing a heat shrinkable tape at the anticorrosive coating part.

In the implementation mode, the lap joint area of the anticorrosive coating at the position of the to-be-repaired opening is cleaned, so that pollutants such as steel sand grains and dust generated in the sand blasting and rust removing process of the step 303 on the surface of the anticorrosive coating can be effectively removed.

And then, bombarding the lap joint area of the anticorrosive coating by adopting a plasma technology, so that a polar functional group is formed on the surface of the lap joint area of the anticorrosive coating.

In the above embodiment, the surface of the anticorrosive layer is bombarded by high-energy plasma, and the plasma can open the polymerized C-H bond, C-C bond, C ═ C bond, or the like on the surface of the anticorrosive layer portion during high-speed movement, and further form polar-C ═ O-, C-OH, -COOH, -COOR, -NH3, and-NO with the ionized plasma gas₂And an isocolar functional group. In addition, the plasma gas can etch the surface of the anticorrosive coating part, so that the surface roughness of the anticorrosive coating and the bonding surface area between the anticorrosive coating and the heat shrinkable tape can be effectively increased.

Optionally, bombarding the lap joint area of the anticorrosive coating by using low-temperature normal-pressure air plasma, wherein the processing voltage of the plasma is 175V, the processing speed is 4m/min, and the processing width is 100-150 mm.

In the above implementation mode, the plasma gas can obtain higher energy, typically several to tens of electron volts, by using the low-temperature normal-pressure air plasma technology, such as the energy of electrons is 0-20 eV, the ion is 0-2 eV, the metastable state particle is 0-20 eV, and the ultraviolet/visible light is 3-40 eV, so that the plasma can effectively open the crystallized and polymerized C-H bond, C-C bond or C ═ C bond (the bond energy of C-H is 4.3eV, the bond energy of C-C is 3.4eV, and the bond energy of C ═ C is 6.1eV) when bombarding the surface of the anticorrosive layer, and make these open bonds and the ionized N have been ionized₂、O₂、CO₂High energetic gas forming polarity-C ═ O-, C-OH, -COOH, -COOR, -NH₃and-NO₂And an isocolar functional group.

S305: and carrying out graft polymerization treatment on the anticorrosive layer part at the repaired mouth position.

Step 305 is implemented by:

respectively brushing solvent-free epoxy primer on the lap joint area and the metal part of the anticorrosive coating at the repaired mouth position, wherein the thickness of the solvent-free epoxy paint on the lap joint area of the anticorrosive coating is kept between 50 and 150 mu m, and the thickness of the solvent-free epoxy paint on the metal part is kept not less than 150 mu m.

In the above implementation manner, on one hand, the polar functional groups participate in the curing reaction of the liquid solvent-free epoxy coating through the induced graft polymerization technology, so that the polar groups can be stably and permanently fixed on the surface of the anticorrosive layer, the surface of the anticorrosive layer is always kept in a stable polarization state, and the adverse effect that the number of the polar functional groups on the surface of the anticorrosive layer after plasma treatment is rapidly reduced along with the time extension is solved (since all substances can spontaneously reduce energy to increase the stability of the polar groups, the high-energy polar groups introduced through plasma treatment can gradually turn over into the interior of the anticorrosive layer along with the time extension, and meanwhile, part of internal atoms can also be transferred to the surface of the anticorrosive layer until the surface of the anticorrosive layer and the internal atoms, groups and the like reach dynamic balance); on the other hand, polar functional groups such as-OH, -COOH, -NH3 and-N02 generated on the surface of the anti-corrosion layer by plasma treatment participate in the polymerization reaction of the solvent-free epoxy, so that the solvent-free epoxy coating and the anti-corrosion layer in the overlapping region are bonded together through chemical bonds, the bonding strength is higher, and the bonding effect is better.

S306: and installing a heat shrinkable tape at the repaired mouth position.

Step 306 is implemented by:

wrapping the heat shrinkable tape at the position of the repaired mouth in an end-to-end connection manner;

the head and tail parts of the heat shrinkable belt are fixed together by the fixing pieces.

In the above implementation, the heat shrinkable tape is immediately wrapped until the solventless epoxy coated surface is tacky to the touch. The heat shrinkable belt is overlapped at the position of a to-be-repaired opening of the pipeline, the head and the tail are connected and wrapped well, and the head and the tail connecting positions are fixed by adopting special heat shrinkable belt fixing pieces. Therefore, the heat shrinkable belt can wrap the position of the pipeline joint coating in the circumferential direction to realize joint coating operation.

Illustratively, when the fixing piece is installed, the circumferential overlapping width of the heat-shrinkable tape and the fixing piece is not less than 80mm, and the overlapping width of the heat-shrinkable tape and the two ends of the anticorrosive layer is not less than 100 mm. Therefore, the heat shrinkable tape can be tightly attached to the pipeline, and the joint coating effect is ensured.

S307: and baking the heat shrinkable tape.

Step 307 is implemented by:

baking the heat-shrinkable tape by an infrared heater to shrink and mold the heat-shrinkable tape;

in the implementation mode, the infrared heating machine is applied to bake the thermal contraction belt backing material and temper and melt the hot melt adhesive, so that the defect that flame is directly contacted with a heated object is overcome, the whole hot melt adhesive is uniformly heated and melted, and the hot melt adhesive is fully diffused, moistened and infiltrated on the surface of an adhered object; and ensuring continuous high-temperature tempering for enough time to ensure that the maleic anhydride in the hot melt adhesive in the lap joint area also participates in the curing reaction of the solvent-free epoxy coating. Finally, the hot melt adhesive, the solvent-free epoxy layer and the anticorrosive layer are bonded by Van der Waals force (simultaneously having orientation force, induction force and dispersion force), and chemical bonding is formed by chemical reaction. The bonding strength of the lap joint area of the hot melt adhesive type polyethylene heat shrinkable tape and the outer anticorrosive layer of the polyethylene three-layer structure (3LPE) is improved.

And heating the heat shrinkable tape subjected to shrinkage molding, and keeping the surface temperature of the heat shrinkable tape at 120-180 ℃ for 10-25 min.

In the implementation mode, the hot melt adhesive and the solvent-free epoxy anticorrosive layer which is in curing reaction are mutually diffused, wetted and permeated by the wrapping force generated after the thermal contraction belt is contracted, so that complete van der waals force can be formed between the hot melt adhesive and the solvent-free epoxy anticorrosive layer, on the other hand, maleic anhydride in the hot melt adhesive participates in the curing of the solvent-free epoxy coating, so that the hot melt adhesive and the liquid solvent-free epoxy coating generate chemical reaction, chemical bonding with higher bonding strength and better bonding effect is formed, and finally, the hot melt adhesive, the solvent-free epoxy layer and the anticorrosive layer are bonded by van der waals force (simultaneously having orientation force, induction force and dispersion force), and chemical bonding is formed due to the generation of chemical bonds, so that the bonding strength of the hot melt adhesive is greatly improved.

S308: and compacting the bulge between the heat shrinkable tape and the joint coating position.

In the above embodiment, the bubble removing operation is performed on the position where the bubbles exist in the heat shrinkable tape until the position meets the requirement, and the adhesive strength between the heat shrinkable tape and the pipe can be further improved.

In addition, after the joint coating operation is carried out on the pipeline by the method, after the installation of the hot melt adhesive type heat shrinkable tape is finished for 24 hours, the peel strength of the lap joint area of the heat shrinkable tape and the anticorrosive layer is tested:

the test equipment was a portable peel strength measuring device, the surface temperature of the heat shrinkable tape was 23.2 ℃, the stretching speed was 10mm/min, the stretching angle was 90 °, and the peel strength was measured to be 175.3N/cm (cohesive failure). The long-term peel strength test was continued: after being soaked in hot water at 80 ℃ for 28 days, the peel strength is 168.5N/cm (cohesive failure); after being soaked in hot water at 80 ℃ for 120 days, the peel strength is 157.8N/cm (cohesive failure); after heat aging at 100 ℃ for 100 days, the peel strength was 165.7N/cm (cohesive failure). Tests show that the method can remarkably improve the bonding strength between the hot melt adhesive type heat shrinkable tape and the anticorrosive layer.

The above method of repairing the pipe is explained in detail by the following examples:

example 1:

in the embodiment, the joint coating method of the pipeline is adopted to perform joint coating operation on the pipeline, wherein the adopted heat-shrinkable tape is in a hot melt adhesive type, and the pipeline is a polyethylene three-layer structure (3LPE) outer anti-corrosion layer buried steel pipeline.

The operation steps include:

1. removing pollutants such as oil, grease, dust and the like on the surface of the steel pipe and the surface of the anticorrosive layer; removing the defects of welding beading, burrs, edges and corners and the like on the surface of the steel pipe; repairing the defects of corrosion resistant layers such as edge warping and cracking at two ends of the steel pipe; and trimming the anticorrosive layers on the two sides of the welded junction into a transition slope with an angle not greater than 30 degrees.

2. The medium frequency inductor heats the pipeline to ensure that the surface temperature of the pipeline is between 50 and 60 ℃.

3. The surface of the sand blasting derusting steel pipe reaches Sa2.5 grade, the depth of the anchor lines is between 40 and 90 mu m, and the dust degree reaches 2 grade.

4. Cleaning the lap joint area on the surface of the anticorrosive layer, and treating the surface of the lap joint area of the anticorrosive layer by adopting low-temperature normal-pressure air plasma. The plasma processing voltage is 50V, the processing speed is 2m/min, and the processing width is 100-150 mm.

5. Immediately brushing matched liquid solvent-free epoxy paint at the position of the pipeline joint; the thickness of the wet film of the solvent-free epoxy coating in the lap joint area of the anticorrosive layer is 50-150 mu m; the wet film thickness of the solvent-free epoxy coating at the metal part of the bare steel is more than or equal to 150 mu m.

6. When the surface of the solvent-free epoxy coating is sticky by touch, the heat shrinkable tape is immediately coated.

And applying an infrared heating machine to bake the heat shrinkable tape. And after the shrinkage is finished, continuously keeping the heating state, and keeping the temperature of the back material of the heat shrinkable tape at 120-140 ℃ for 25 min. And removing the infrared heating machine tool, and removing the bubbles in the heat shrinkable tape.

And (3) after the hot melt adhesive type heat shrinkable tape is installed for 24 hours, testing the peel strength of the lap joint area of the heat shrinkable tape and the anticorrosive layer:

the test equipment was a portable peel strength measuring device, the surface temperature of the heat shrinkable tape was 22.4 ℃, the stretching speed was 10mm/min, the stretching angle was 90 °, and the peel strength was 172.7N/cm (cohesive failure) was measured.

The long-term peel strength test was continued: after being soaked in hot water at 80 ℃ for 28 days, the peel strength is 166.2N/cm (cohesive failure); after being soaked in hot water at 80 ℃ for 120 days, the peel strength is 158.7N/cm (cohesive failure); after heat aging at 100 ℃ for 100 days, the peel strength was 162.4N/cm (cohesive failure).

The above data illustrate that the method provided by the embodiment can significantly improve the bonding strength between the hot melt adhesive type heat shrinkable tape and the anticorrosive layer.

Example 2:

in the embodiment, the joint coating method of the pipeline is adopted to perform joint coating operation on the pipeline, wherein the adopted heat-shrinkable tape is in a hot melt adhesive type, and the pipeline is a polyethylene three-layer structure (3LPE) outer anti-corrosion layer buried steel pipeline.

The operation steps include:

1. removing pollutants such as oil, grease, dust and the like on the surface of the steel pipe and the surface of the anticorrosive layer; removing the defects of welding beading, burrs, edges and corners and the like on the surface of the steel pipe; repairing the defects of corrosion resistant layers such as edge warping and cracking at two ends of the steel pipe; and trimming the anticorrosive layers on the two sides of the welded junction into a transition slope with an angle not greater than 30 degrees.

2. And (3) heating the steel pipe by medium-frequency induction to enable the surface temperature of the steel pipe to be 60-70 ℃.

3. The surface of the sand blasting derusting steel pipe reaches Sa2.5 grade, the depth of the anchor lines is between 40 and 90 mu m, and the dust degree reaches 2 grade.

4. Cleaning the lap joint area on the surface of the anticorrosive layer, and treating the surface of the lap joint area of the anticorrosive layer by adopting low-temperature normal-pressure air plasma. The plasma processing voltage is 175V, the processing speed is 4m/min, and the processing width is 100-150 mm.

5. Immediately brushing matched liquid solvent-free epoxy paint; the thickness of the wet film of the solvent-free epoxy coating in the lap joint area of the anticorrosive layer is 50-150 mu m; the wet film thickness of the solvent-free epoxy coating on the surface of the bare steel is more than or equal to 150 mu m.

6. When the surface of the solvent-free epoxy coating is sticky by touch, the heat shrinkable tape is immediately coated. And applying an infrared heating machine to bake the heat shrinkable tape. And after the shrinkage is finished, continuously keeping the heating state, and keeping the temperature of the thermal shrinkage tape back material at 140-160 ℃ for 17.5 min. And removing the infrared heating machine tool to carry out bubble removing operation.

And (3) after the hot melt adhesive type heat shrinkable tape is installed for 24 hours, testing the peel strength of the lap joint area of the heat shrinkable tape and the anticorrosive layer:

the test equipment was a portable peel strength measuring device, the surface temperature of the heat shrinkable tape was 22.8 ℃, the stretching speed was 10mm/min, the stretching angle was 90 °, and the peel strength was 185.6N/cm (cohesive failure) was measured. The long-term peel strength test was continued: after being soaked in hot water at 80 ℃ for 28 days, the peel strength is 176.1N/cm (cohesive failure); after being soaked in hot water at 80 ℃ for 120 days, the peel strength is 168.5N/cm (cohesive failure); after heat aging at 100 ℃ for 100 days, the peel strength was 180.2N/cm (cohesive failure).

The above data illustrate that the method provided by the embodiment can significantly improve the bonding strength between the hot melt adhesive type heat shrinkable tape and the anticorrosive layer.

Example 3:

in the embodiment, the joint coating method of the pipeline is adopted to perform joint coating operation on the pipeline, wherein the adopted heat-shrinkable tape is in a hot melt adhesive type, and the pipeline is a polyethylene three-layer structure (3LPE) outer anti-corrosion layer buried steel pipeline.

The operation steps include:

1. removing pollutants such as oil, grease, dust and the like on the surface of the steel pipe and the surface of the anticorrosive layer; removing the defects of welding beading, burrs, edges and corners and the like on the surface of the steel pipe; repairing the defects of corrosion resistant layers such as edge warping and cracking at two ends of the steel pipe; and trimming the anticorrosive layers on the two sides of the welded junction into a transition slope with an angle not greater than 30 degrees.

2. And (3) heating the steel pipe by medium-frequency induction to enable the surface temperature of the steel pipe to be 70-80 ℃.

3. The surface of the sand blasting derusting steel pipe reaches Sa2.5 grade, the depth of the anchor lines is between 40 and 90 mu m, and the dust degree reaches 2 grade.

4. Cleaning the lap joint area on the surface of the anticorrosive layer, and treating the surface of the lap joint area of the anticorrosive layer by adopting low-temperature normal-pressure air plasma. The plasma processing voltage is 300V, the processing speed is 6m/min, and the processing width is 100-150 mm.

5. Immediately brushing matched liquid solvent-free epoxy paint; the thickness of the wet film of the solvent-free epoxy coating in the lap joint area of the anticorrosive layer is 50-150 mu m; the wet film thickness of the solvent-free epoxy coating on the surface of the bare steel is more than or equal to 150 mu m.

6. When the surface of the solvent-free epoxy coating is sticky by touch, the heat shrinkable tape is immediately coated. And applying an infrared heating machine to bake the heat shrinkable tape. And after the shrinkage is finished, continuously keeping the heating state, and keeping the temperature of the thermal shrinkage tape back material between 160 and 180 ℃ for 10 min. And removing the infrared heating machine tool to carry out bubble removing operation.

And (3) after the hot melt adhesive type heat shrinkable tape is installed for 24 hours, testing the peel strength of the lap joint area of the heat shrinkable tape and the anticorrosive layer:

the test equipment was a portable peel strength measuring device, the surface temperature of the heat shrinkable tape was 23.2 ℃, the stretching speed was 10mm/min, the stretching angle was 90 °, and the peel strength was measured to be 166.6N/cm (cohesive failure). The long-term peel strength test was continued: peel strength of 159.7N/cm (cohesive failure) after soaking in hot water at 80 ℃ for 28 d; after being soaked in hot water at 80 ℃ for 120 days, the peel strength is 151.5N/cm (cohesive failure); after heat aging at 100 ℃ for 100 days, the peel strength was 155.2N/cm (cohesive failure).

The above data illustrate that the method provided by the embodiment can significantly improve the bonding strength between the hot melt adhesive type heat shrinkable tape and the anticorrosive layer.

The above description is meant to be illustrative of the principles of the present disclosure and not to be taken in a limiting sense, and any modifications, equivalents, improvements and the like that are within the spirit and scope of the present disclosure are intended to be included therein.