In-situ forming device of sacrificial anode and anticorrosion protection layer and construction method thereof

Abstract

The present application belongs to the technical field of buried pipeline joint protection, and relates to a sacrificial anode cooperative anticorrosion protection layer in-situ forming device and a construction method thereof. The device comprises a functionalized pipeline joint section, an anode array, a multifunctional filling material and an intelligent control center. The outer wall of the functionalized pipeline joint section is pre-fabricated with an electrically conductive layer having the functions of a cathode and a heating body. The anode array is arranged around and has the functions of electric field construction and long-term sacrificial anode. The method comprises the steps of excavating a trench, butting pipelines, arranging the anode array and filling the material. The electric field and temperature are controlled by the intelligent control center to make the material solidify in-situ to form a high-density protection layer, and finally a sacrificial anode cathodic protection mechanism is constructed. The present application solves the problems of uneven anticorrosion density and process disconnection of traditional pipeline joints, realizes the integration of forming and anticorrosion, is simple and convenient to construct, has low cost, and can be widely applied to buried pipeline joint protection.

Description

Technical Field

[0001] This invention belongs to the field of buried pipeline joint protection technology, and relates to an in-situ forming device for sacrificial anode synergistic anti-corrosion protective layer and its construction method. Background Technology

[0002] Pipelines (such as PCCP pipelines) are critical facilities in water resource transportation, energy transmission, and other fields. Pipe joints are weak points in corrosion prevention, and their long-term operational stability directly affects project safety. Traditional buried pipelines rely on layered compaction of backfill soil for external protection. However, uneven density distribution can easily occur during soil compaction, leading to unbalanced stress on the pipeline and making it prone to deformation or even damage after long-term use.

[0003] Meanwhile, to achieve corrosion protection, traditional processes require applying an additional anti-corrosion coating, such as epoxy asphalt, before the pipeline leaves the factory. This step is performed separately from the backfill compaction process. The coating is easily damaged by mechanical impacts during pipeline transportation, hoisting, and soil compaction. Furthermore, gaps always exist between the coating and the backfill, allowing moisture and corrosive substances to easily seep in, leading to corrosion failure and severely impacting the pipeline's service life.

[0004] Furthermore, traditional anti-corrosion coatings are applied post-construction, resulting in uneven distribution of the anti-corrosion agent and failing to provide uniform protection to all parts of the pipeline. This method not only shortens the service life of the pipeline but also involves a cumbersome and costly construction process, making it difficult to meet the requirements for long-term safe operation of pipelines. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a sacrificial anode synergistic anti-corrosion protective layer in-situ forming device and its construction method.

[0006] To achieve the objectives of this invention, the following technical solutions are adopted.

[0007] An in-situ forming device for sacrificial anode synergistic anti-corrosion protective layer of pipe joints includes a functionalized pipe joint section, an anode array, a multifunctional filling material, and an intelligent control center;

[0008] The outer wall of the functionalized pipe joint section is prefabricated with a conductive layer, which serves as both a cathode and a heating element, and is connected to the intelligent control center via a cable.

[0009] The anode array is distributed around the pipe joint, vertically fixed to the buried trench sand cushion layer, and connected to the intelligent control center via cable, serving both as an electric field construction and long-term sacrificial anode function.

[0010] The multifunctional filler material fills the gap between the functionalized pipe joint section and the anode array;

[0011] The intelligent control center is used to regulate the electric field, temperature, and the entire construction process.

[0012] The multifunctional filler material is composed of the following components by mass ratio: 60-70% aggregate, 20-25% cementitious material, 3-5% thermosensitive curing agent, and 2-4% composite corrosion inhibitor.

[0013] Preferably, the aggregate is quartz sand or river sand with a particle size of 0.1-2.0 mm, and has a mud content of ≤1% and a moisture content of ≤0.5%.

[0014] The cementing material is sulfoaluminate cement or rapid-hardening silicate cement with a strength grade ≥ 42.5.

[0015] The thermosensitive curing agent is polyethylene glycol diacrylate with a molecular weight of 400-600, and is combined with 0.5-1% by mass of azobisisobutyronitrile as an initiator;

[0016] The composite corrosion inhibitor is composed of sodium nitrite and benzotriazole in a mass ratio of 3:1.

[0017] Preferably, the conductive layer is a conductive coating or a conductive fabric;

[0018] The conductive coating has a volume resistivity ≤10. -3 A graphene-modified epoxy resin conductive coating or a carbon nanotube-modified polyurethane conductive coating with an Ω·m, a thickness of 0.5-1.0 mm, and an adhesion of ≥5 MPa; the conductive coating can closely adhere to the arc-shaped outer wall of the pipe joint to form a continuous conductive path, while also having good corrosion resistance and adhesion to prevent it from falling off in the buried environment.

[0019] The conductive fabric has a surface resistivity of ≤10. -2 The conductive fabric is made of carbon fiber woven fabric or nickel-plated polyester fabric impregnated with conductive silver paste, with a strength of Ω / m², a thickness of 1-2 mm, and a tensile strength ≥300 N / 5 cm. The conductive fabric can be bent and adapted to irregularly shaped connectors, and is fixed by adhesive bonding. The seams are sealed with conductive silver paste to ensure continuity of conductivity.

[0020] Preferably, the anode array is made of zinc alloy, aluminum alloy, or magnesium alloy and processed into long strip-shaped electrode plates. The electrode plates are arranged uniformly in a ring around the functionalized pipe joint section, with a spacing of 30-50 cm, and are vertically inserted into the sand pad layer for fixation 5-8 cm. The anode array not only satisfies the anode function during the molding stage but also provides cathodic protection for the subsequent formation of sacrificial anodes.

[0021] Core electric field and protection logic

[0022] During the molding stage, a DC electric field is formed between the conductive layer and the anode array. The intelligent control module outputs DC voltage and current, forming a closed loop in the conductive layer → multifunctional filler material → anode array, driving the directional movement of ions, ensuring uniform material distribution and corrosion inhibitor aggregation.

[0023] Long-term corrosion protection mechanism: After the protective layer is formed, the intelligent control module is removed, and the anode array is directly connected to the conductive layer by cable. Because the electrode potential of the anode array material is lower than that of the conductive layer, it will preferentially undergo oxidation and sacrifice itself to provide protective current for the conductive layer, delaying the corrosion of the cathode and forming a long-term stable protective mechanism of sacrificing the anode to protect the cathode.

[0024] During the molding stage, the conductive layer acts as a cathode to participate in the formation of the electric field. In addition to its cathode function, it also acts as a heat source to generate heat and trigger the material to solidify. During long-term use, the conductive layer acts as a cathode to receive the protective current generated by the sacrificial anode, thus achieving the anti-corrosion function.

[0025] A construction method based on an in-situ forming device for sacrificial anode synergistic anti-corrosion protective layer of pipe joints includes the following steps:

[0026] S51. Excavate a trench at the pre-set location of the buried pipe joint, level the bottom of the trench and lay a sand cushion layer.

[0027] S52. Hoist the two sections of pipe with the outer pre-conductive layer onto the sand pad layer in the trench to complete the connection of the functional pipe joint section, adjust the pipe position and check that the conductive layer is undamaged.

[0028] S53. Fill the area around the pipe with a multi-functional filling material to initially fix the pipe.

[0029] S54. Distribute the anode array evenly around the pipe joint installation path, and insert it vertically into the sand pad layer for fixation, ensuring that the distance between the electrode plate and the outer wall of the pipe is uniform.

[0030] S55. Fill the gap between the functionalized pipe joint section and the anode array with multifunctional filler material until the filling height is flush with the top of the joint. During the filling process, ensure that the material is dense and without gaps.

[0031] S56. Connect the intelligent control center to the conductive layer and the anode array respectively via cables to complete the system debugging;

[0032] S57. Start the intelligent control center to establish a DC electric field between the conductive layer and the anode array. The electric field acts for 30-60 minutes, driving the directional movement of moisture, cementitious ions and preservative ions in the multifunctional filler material.

[0033] S58. The intelligent control center regulates the current and uses the conductive layer to generate heat, controlling the joint interface temperature at 40-60℃, so that the multifunctional filler material is cured and forms a solidified layer with gradually decreasing density from the inside to the outside.

[0034] S59. Under the continuous action of the electric field, the composite corrosion inhibitor in the multifunctional filler material is directionally aggregated on the outer surface of the pipe joint and is formed synchronously with the solidified dense layer to form an internal anti-corrosion layer.

[0035] S510. After the material has cured, the mechanical properties and anti-corrosion effect of the protective layer are evaluated through visual inspection and sampling inspection.

[0036] S511. After confirming that the protective layer meets the design requirements, remove the intelligent control center, connect the anode array and the conductive layer directly with a cable, and wrap the cable joint with insulating and anti-corrosion tape to form a cathodic protection mechanism for the sacrificial anode, and then backfill the trench.

[0037] Preferably, when filling with multifunctional filler material, a layered vibration method is adopted, with each layer not exceeding 30cm in thickness.

[0038] Preferably, the inner layer density of the solidified dense layer is ≥1.8g / cm³, and the outer layer density is ≥1.5g / cm³.

[0039] Preferably, the thickness of the anti-corrosion layer is 5-10 cm.

[0040] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0041] 1. Dual protection of structure and corrosion: The high-density protective layer not only provides mechanical support and physical isolation, but also sacrifices the anodic cathodic protection mechanism to achieve electrochemical corrosion protection. The two work together to greatly extend the service life of the joint.

[0042] 2. Long-lasting and stable anti-corrosion effect: It avoids the problems of traditional anti-corrosion layers peeling off and failing. The sacrificial anode continuously provides protective current, making it suitable for pipelines buried underground for a long time.

[0043] 3. Significantly reduced costs: Construction is only carried out on pipe joints, reducing material usage and construction scope. Furthermore, the anode array provides protection not only during the forming stage but also in the later stages, eliminating the need for additional sacrificial anodes, resulting in lower overall costs.

[0044] 4. Innovative and efficient process: The construction process strictly follows the logic of "positioning-fixing-filling-intelligent molding-long-term protection," and is easy to operate. Multiple processes are completed in one go, which can improve construction efficiency;

[0045] 5. Avoid construction damage: There is no mechanical impact during construction. The pipeline is fixed before subsequent operations are carried out. This operation can effectively prevent damage to joints and protective structures, and ensure construction quality.

[0046] The essence of this invention is to transform pipeline protection from the high-cost "full pipe coverage" model and the traditional model of "separation of molding and corrosion prevention" to an economical and efficient model of "joint protection + molding-corrosion prevention integration". Through electrochemical in-situ construction technology and sacrificial anode synergy mechanism, a structure-function integrated intelligent protective layer is formed at the joint, which is a key technological breakthrough to ensure the long-term safe operation of underground pressure pipelines. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the overall structure of the intelligent in-situ forming device of the present invention;

[0048] Figure 2 This is a partial structural schematic diagram of the functionalized pipe of the present invention;

[0049] Figure 3 This is a schematic diagram of the sacrificial anode cathode protection connection of the present invention;

[0050] In the diagram, 1 is a functionalized pipe, 2 is an anode array, 3 is a multifunctional filling material, 4 is an intelligent control module, and 5 is a conductive layer. Detailed Implementation

[0051] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0052] As an embodiment 1 of the present invention, such as Figure 1-3 As shown, an in-situ forming device for a sacrificial anode synergistic anti-corrosion protective layer for pipe joints includes a functionalized pipe joint section 1, an anode array 2, a multifunctional filling material 3, an intelligent control module 4, and a conductive layer 5.

[0053] Functional pipe joint section 1 is formed by connecting two conventional PPCP pipe sections. The outer wall of the pipe has a pre-fabricated conductive layer 5. If a conductive coating is selected, graphene-modified epoxy resin conductive coating is used. It is applied by high-pressure airless spraying in 2-3 coats, with each coat being 0.2-0.3 mm thick and the total thickness controlled between 0.5-1.0 mm. After spraying, it needs to be cured at room temperature for 24 hours to ensure that the coating is free of pinholes and drips, and has an adhesion of ≥5 MPa. If a conductive fabric is selected, carbon fiber woven fabric impregnated with conductive silver paste is cut to fit the pipe size. Conductive adhesive is evenly applied to the outer wall of the pipe, and the fabric is flatly pasted. The fabric overlaps by 5-10 cm at the joint and is then coated with conductive silver paste. After compaction, it is cured for 12 hours to ensure that there are no gaps between the fabric and the outer wall of the pipe, and that the conductivity is continuous.

[0054] The anode array 2 uses sacrificial anode materials such as zinc alloy, aluminum alloy, or magnesium alloy, which are processed into long strip-shaped electrode plates. The length of these plates matches the length of the pipe joint section, typically 1-2m, with a width of 10-15cm and a thickness of 2-3mm. The electrode plates are arranged uniformly in a ring around the functionalized pipe joint section 1, with a spacing of 30-50cm. They are vertically inserted 5-8cm into the buried trench sand pad for fixation, ensuring full contact between the anode array and the multifunctional filler material 3. This not only fulfills the anode function during the molding stage but also provides a continuous protective current for the subsequent sacrificial anode reaction.

[0055] Multifunctional filler material 3 is formulated according to the following mass ratio: Quartz sand with a particle size of 0.1-2.0mm is selected as aggregate, accounting for 60-70%, with a mud content of ≤1% and a moisture content of ≤0.5% to ensure the cleanliness and stability of the skeleton; 42.5 grade sulfoaluminate cement is selected as cementing material, accounting for 20-25%, with moderate heat of hydration and rapid early strength development, which can meet the requirements of in-situ rapid curing; Polyethylene glycol diacrylate (PEGDA) with a molecular weight of 400-600 is selected as thermosensitive curing agent, accounting for 3-5%, and 0.5-1% of azobisisobutyronitrile (AIBN) by mass of PEGDA is added as initiator to ensure that it can polymerize rapidly at 40-60℃; Sodium nitrite and benzotriazole are compounded at a mass ratio of 3:1 as composite corrosion inhibitor, accounting for 2-4% of the total, which has both anodic passivation and surface adsorption functions and is suitable for electric field directional aggregation characteristics. After mixing the above materials with water, they can be used for initial pipe fixing and subsequent filling. The filling height should be flush with the top of the joint. When filling, use a vibrator to gently tamp the mixture to ensure there are no gaps and to create a good electrolyte environment to ensure electric field conduction and ion movement.

[0056] The intelligent control module 4 is an integrated control cabinet, housing an electric field generation module and a temperature control module. The electric field generation module can output 0-50V DC voltage and 0-10A current, which can be continuously adjusted; the temperature control module has a temperature control accuracy of ±1℃. The electric field generation module is electrically connected to the conductive layer 5 and the anode array 2 via copper cables, respectively. The temperature control module achieves closed-loop control of current regulation by real-time acquisition of the conductive layer temperature data.

[0057] As an embodiment of the present invention, such as Figures 1 to 3 As shown, the specific construction steps of this device are as follows:

[0058] 1. Excavate a trench at the pre-set location of the buried pipe joint. The trench length is 0.5m on each side of the joint section length, and the width is 80-100cm greater than the outer diameter of the pipe. Level the bottom of the trench and lay a 5-10cm sand cushion layer, and compact it to ensure that the bottom is flat.

[0059] 2. Use a crane to lift the two sections of prefabricated conductive layer pipes onto the sand cushion layer in the trench, and precisely connect them according to the design to form functional pipe joint section 1. Adjust the position of the pipes to make the axis horizontal, seal the joint, and then check that the conductive layer 5 is undamaged.

[0060] 3. Fill the area around the pipe with the well-mixed multi-functional filler material 3, and gently compact it to achieve the purpose of initial fixation of the pipe and prevent the pipe from shifting during subsequent operations;

[0061] 4. Arrange the electrode plates of anode array 2 evenly around the pipe joint at a design spacing of 30-50cm, and fix them vertically into the sand pad layer for 5-8cm. Ensure that the electrode plates are perpendicular to the bottom of the trench and maintain a distance of 10-15cm from the outer wall of the pipe.

[0062] 5. Continue to fill the gap between the functionalized pipe joint section 1 and the anode array 2 with multifunctional filler material 3. It is necessary to fill in layers and vibrate, with each layer not exceeding 30cm in thickness, until the filling height is flush with the top of the joint, so as to ensure that the material is dense without gaps or honeycomb defects.

[0063] 6. Place the intelligent control module 4 in a flat and dry area of ​​the construction site. Connect the cathode terminal of the electric field generating module to the conductive layer 5 and the anode terminal to the anode array 2 via a cable. Wrap the wiring with insulating tape for protection. Complete the power-on test and system debugging.

[0064] 7. Start the electric field generation module of the intelligent control module 4, set the initial voltage to 20V, establish a DC electric field between the conductive layer and the anode array, and the electric field lasts for 30-60 minutes, which drives the moisture, cementing ions and composite corrosion inhibitor ions in the multifunctional filling material 3 to move in a directional manner, gather and be evenly distributed on the outer wall of the joint;

[0065] 8. Set the target temperature of the intelligent control module 4 to 40-60℃. The system automatically adjusts the magnitude of the electric field current and uses the heat generated by the conductive layer 5 to heat the filling material, ensuring that the temperature is stable within the set target range. This triggers the reaction of the temperature-sensitive curing agent, allowing the filling material to cure quickly and form a solidified layer with gradually decreasing density from the inside to the outside, i.e., the inner layer density ≥1.8g / cm³ and the outer layer density ≥1.5g / cm³.

[0066] 9. During the curing process, the electric field will continue to act, during which the composite corrosion inhibitor will be directionally accumulated on the outer surface of the joint and will be formed synchronously with the cured dense layer, forming an internal anti-corrosion layer with a thickness of 5-10cm;

[0067] 10. After the filler material has fully cured (approximately 24-48 hours), visually inspect for cracks and peeling, and conduct sampling checks to ensure it meets the requirements of compressive strength ≥15MPa and impermeability coefficient ≤1×10⁻⁶. -7cm / s, thereby evaluating the mechanical properties and corrosion resistance of the protective layer;

[0068] 11. After ensuring that the protective layer meets the requirements, remove the intelligent control module 4, select copper cables, connect all the anode arrays 2 in series, and connect them to the conductive layer 5. Wrap and seal the joints with insulating and anti-corrosion tape to prevent corrosion and failure when buried. Then backfill the trench in layers, compact the soil, and complete the overall construction.

[0069] The construction method of this device is based on the principle of electrochemical in-situ construction, and its core consists of three parts. The specific construction steps are as follows:

[0070] 1. Basic positioning stage: Prioritize the excavation of the trench and the hoisting and connection of the pipeline. Fix the position of the pipeline by filling in some filling material to ensure the accurate placement of the electrodes in the future.

[0071] 2. Electrode and material filling stage: The anode array is arranged and fixed around the pipeline. The filling material is completely completed to ensure full contact between the electrodes and the material, providing an electrolyte environment for the formation of the power plant;

[0072] 3. Intelligent molding and long-term protection stage: Connect the intelligent control module, use an electric field to make the material evenly distributed, and heat to trigger the material to solidify and form a protective layer; then remove the intelligent control module and connect the anode array with the conductive layer to achieve the function of sacrificing the anode to protect the cathode, realizing the integration of short-term molding and long-term corrosion protection.

[0073] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. An in-situ forming device for a sacrificial anode synergistic anti-corrosion protective layer for pipe joints, characterized in that: This includes functionalized pipe joint sections, anode arrays, multifunctional filling materials, and an intelligent control center; The outer wall of the functionalized pipe joint section is prefabricated with a conductive layer, which serves as both a cathode and a heating element, and is connected to the intelligent control center via a cable. The anode array is distributed around the pipe joint, vertically fixed to the buried trench sand cushion layer, and connected to the intelligent control center via cable, serving both as an electric field construction and long-term sacrificial anode function. The multifunctional filler material fills the gap between the functionalized pipe joint section and the anode array; The intelligent control center is used to regulate the electric field, temperature, and the entire construction process. The multifunctional filler material is composed of the following components by mass ratio: 60-70% aggregate, 20-25% cementitious material, 3-5% thermosensitive curing agent, and 2-4% composite corrosion inhibitor.

2. The in-situ forming device for sacrificial anode synergistic anti-corrosion protective layer of pipe joints according to claim 1, characterized in that: The aggregate is quartz sand or river sand with a particle size of 0.1-2.0 mm, and has a mud content of ≤1% and a moisture content of ≤0.5%. The cementing material is sulfoaluminate cement or rapid-hardening silicate cement with a strength grade ≥ 42.

5. The thermosensitive curing agent is polyethylene glycol diacrylate with a molecular weight of 400-600, and is combined with 0.5-1% by mass of azobisisobutyronitrile as an initiator; The composite corrosion inhibitor is composed of sodium nitrite and benzotriazole in a mass ratio of 3:

1.

3. The in-situ forming device for sacrificial anode synergistic anti-corrosion protective layer of pipe joints according to claim 1, characterized in that: The conductive layer is a conductive coating or a conductive fabric; The conductive coating has a volume resistivity ≤10. -3 Graphene-modified epoxy resin conductive coatings or carbon nanotube-modified polyurethane conductive coatings with an Ω·m thickness of 0.5-1.0 mm and an adhesion strength of ≥5 MPa. The conductive fabric has a surface resistivity of ≤10. -2 Carbon fiber woven fabric or nickel-plated polyester fabric impregnated with conductive silver paste, with a strength of Ω / m², a thickness of 1-2mm, and a tensile strength of ≥300N / 5cm.

4. The in-situ forming device for sacrificial anode synergistic anti-corrosion protective layer of pipe joints according to claim 1, characterized in that: The anode array is made of zinc alloy, aluminum alloy or magnesium alloy and processed into long strip electrode plates. The electrode plates are arranged in a ring around the functionalized pipe joint section with a spacing of 30-50cm and are vertically inserted into the sand pad layer for fixation 5-8cm.

5. A construction method based on the device described in any one of claims 1-4, characterized in that: Includes the following steps: S51. Excavate a trench at the pre-set location of the buried pipe joint, level the bottom of the trench and lay a sand cushion layer. S52. Hoist the two sections of pipe with the outer pre-conductive layer onto the sand pad layer in the trench to complete the connection of the functional pipe joint section, adjust the pipe position and check that the conductive layer is undamaged. S53. Fill the area around the pipe with a multi-functional filling material to initially fix the pipe. S54. Distribute the anode array evenly around the pipe joint installation path, and insert it vertically into the sand pad layer for fixation, ensuring that the distance between the electrode plate and the outer wall of the pipe is uniform. S55. Fill the gap between the functionalized pipe joint section and the anode array with multifunctional filler material until the filling height is flush with the top of the joint. During the filling process, ensure that the material is dense and without gaps. S56. Connect the intelligent control center to the conductive layer and the anode array respectively via cables to complete the system debugging; S57. Start the intelligent control center to establish a DC electric field between the conductive layer and the anode array. The electric field acts for 30-60 minutes, driving the directional movement of moisture, cementitious ions and preservative ions in the multifunctional filler material. S58. The intelligent control center regulates the current and uses the conductive layer to generate heat, controlling the joint interface temperature at 40-60℃, so that the multifunctional filler material is cured and forms a solidified layer with gradually decreasing density from the inside to the outside. S59. Under the continuous action of the electric field, the composite corrosion inhibitor in the multifunctional filler material is directionally aggregated on the outer surface of the pipe joint and is formed synchronously with the solidified dense layer to form an internal anti-corrosion layer. S510. After the material has cured, the mechanical properties and anti-corrosion effect of the protective layer are evaluated through visual inspection and sampling inspection. S511. After confirming that the protective layer meets the design requirements, remove the intelligent control center, connect the anode array and the conductive layer directly with a cable, and wrap the cable joint with insulating and anti-corrosion tape to form a cathodic protection mechanism for the sacrificial anode, and then backfill the trench.

6. The construction method according to claim 5, characterized in that: When filling with multifunctional filler material, a layered vibration method should be adopted, with each layer not exceeding 30cm in thickness.

7. The construction method according to claim 5, characterized in that: The inner layer density of the solidified dense layer is ≥1.8g / cm³, and the outer layer density is ≥1.5g / cm³.

8. The construction method according to claim 5, characterized in that: The thickness of the anti-corrosion layer is 5-10cm.

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