Hydraulic self-driven anti-corrosion layer structure at joint of ring type steel pipe

Abstract

The hydraulic self-driven anti-corrosion layer structure is characterized in that an annular groove is formed in the pipe wall of the joint of the ring type steel pipe, and the anti-corrosion layer structure is arranged at the annular groove; comprising an anode metal layer arranged on the outer side of a steel pipe, a CNF film serving as a positive electrode of the nano friction generator and a PDMS film serving as a negative electrode of the nano friction generator, the CNF film and the PDMS film are sequentially arranged on the inner side of the steel pipe, a wire is arranged on the inner side of the CNF film and connected with a copper foil contact piece in the anode metal layer, and a wire is arranged on the inner side of the PDMS film and connected with a copper foil contact piece in the steel pipe. Double mechanisms of physical corrosion prevention and electrochemical corrosion prevention are fused, and a more comprehensive and efficient solution is provided for pipeline corrosion prevention. The service life of the steel structure pipeline is remarkably prolonged, and the water quality safety of drinking water is continuously guaranteed in the long-term service process of the pipeline. And meanwhile, the design further has a potential steel pipe repairing function, and extra guarantee is provided for long-term stable operation of the pipeline.

Description

Technical Field

[0001] The invention belongs to the technical field of anti-corrosion pipeline lining manufacturing, and specifically relates to a hydraulic self-driven anti-corrosion layer structure at a ring-type steel pipe interface. Background Art

[0002] Pipe scale is a type of iron-containing compounds, organic matter, silicon-aluminum compounds, etc. formed by suspended matter that is not completely removed during drinking water treatment in the pipeline through flocculation, precipitation, resuspension, etc. The content in ductile iron pipes is 0.1-40 g·m -1 , pipe scale is prone to breed bacteria and microorganisms, which may cause odor, discoloration and other problems, and in severe cases may even cause food poisoning symptoms such as diarrhea and vomiting, posing a potential threat to human health. Long-term sedimentation sludge contains heavy metals such as arsenic, cadmium, and mercury. These toxic substances will be absorbed by the human body with the water flow. Long-term drinking may cause developmental delay, frailty and multiple diseases in children, and various chronic diseases and even cancer in the elderly. Compared with the pipeline body, the pipeline joint is more prone to corrosion. Pipeline joints often involve welding or connection of different materials, such as steel pipes and valves, flanges and other connectors. The potential difference between these materials may cause electrochemical corrosion. Data show that the corrosion rate of the joints between different materials is often higher than that of the pipeline body of a single material. In addition, pipeline joints usually have complex geometric shapes and stress distributions, such as welds, threads, etc. These structural differences may cause corrosive media to accumulate at the joints, thereby accelerating the corrosion process. Local corrosion accounts for about 80% of the entire corrosion, and pipeline joints are often high-incidence areas for local corrosion. The corrosion rate of pipeline joints may be several times or even dozens of times higher than that of the pipeline body.

[0003] At present, the anti-corrosion design of pipeline joints mostly adopts physical structure. The principle is to cover the inner surface of the pipeline joint with a layer of material with special properties to form a physical barrier to protect the pipeline. It can be divided into coating anti-corrosion structure, lining anti-corrosion and outer jacket anti-corrosion. Its characteristics are simple construction, low cost, wide application range, etc., but it also has many disadvantages such as relatively poor protection performance, susceptibility to mechanical damage, acid and alkali corrosion and other factors, and low durability. The electrochemical anti-corrosion technology is based on the electrochemical principle. It implements specific measures on metal equipment to transform it into the cathode in the corrosion battery system, thereby achieving the purpose of preventing or reducing metal corrosion. It has the advantages of significant anti-corrosion effect, convenient construction, and can effectively extend the service life of metal workpieces. Due to the special environment of the pipeline joint, the automatic operation of the electrochemical reaction can be realized in combination with the hydraulic self-driving system, thereby realizing the comprehensive management and control of the pipeline anti-corrosion process. As a way of utilizing clean energy, the hydraulic self-driving system is significantly environmentally friendly. It does not require additional energy supply and relies entirely on hydraulic drive, thus avoiding the problems of energy consumption and environmental pollution. This feature makes the hydraulic self-driving system of great value in sustainable development and green energy utilization. Therefore, it is necessary to carry out hydraulic self-driving anti-corrosion design for pipelines to effectively inhibit the generation and transformation of pipe scale, thereby avoiding affecting the quality of drinking water. Summary of the invention

[0004] In view of the above problems, the object of the present invention is to provide a hydraulic self-driven anti-corrosion layer structure at the annular steel pipe interface.

[0005] In order to effectively inhibit pipeline corrosion, the present invention adopts a new idea: the multi-layer anti-corrosion structure arranged inside the pipeline uses the pressure generated by water flow to make the cellulose (CNF) aerogel membrane and the porous polydimethylsiloxane (PDMS) aerogel membrane squeeze and contact each other, forming a nano friction generator (TENG) structure, thereby generating a certain amount of alternating current, and integrating it into direct current through the power management system as a protective current for the metal pipeline. The negative electrode is connected to the protected object, and the positive electrode is connected to the auxiliary anode. A current loop is formed through the electrolyte environment in the pipeline, thereby avoiding pipeline corrosion.

[0006] The specific technical solutions are as follows: A hydraulic self-driven anti-corrosion layer structure at an annular steel pipe interface, wherein an annular groove is provided in the pipe wall at the annular steel pipe interface, and the anti-corrosion layer structure is provided at the annular groove, comprising an anode metal layer provided on the outer surface of the steel pipe, a CNF film as the positive electrode of a nano-friction generator and a PDMS film as the negative electrode of the nano-friction generator, which are sequentially provided on the inner surface of the steel pipe, a wire is provided on the inner side of the CNF film to be connected to a copper foil contact piece in the anode metal layer, and a wire is provided on the inner side of the PDMS film to be connected to a copper foil contact piece in the steel pipe.

[0007] Furthermore, a chemical medium filling layer is provided between the anode metal layer and the steel pipe, and the composition of the chemical medium filling layer is 80% calcium sulfate, 15% bentonite and 5% sodium sulfate in terms of mass fraction.

[0008] Furthermore, the length of the anti-corrosion layer structure at each annular steel pipe interface is not less than 50 mm, the middle of the anti-corrosion layer structure is embedded in the annular groove, and the lengths of the annular grooves extending from both ends are equal.

[0009] Furthermore, the outer surface area of ​​the chemical medium filling layer is slightly larger than the inner surface area of ​​the anode metal layer.

[0010] Furthermore, the material of the anode metal layer is AZ31B high-efficiency aluminum alloy.

[0011] Furthermore, the thickness of the PDMS film is 0.4-0.60 mm, the thickness of the CNF film is 0.3-0.50 mm, and the thickness of the anode metal layer is 25-35 mm.

[0012] Furthermore, the adhesive material between the CNF membrane and the anode metal layer is low-whitening metal glue.

[0013] The beneficial effects of the present invention are: 1) The present invention can utilize the pressure generated by water flow to squeeze and contact the CNF membrane and the PDMS membrane to form a nano friction generator (TENG) structure, converting the kinetic energy of water into electrical energy, thereby generating a certain amount of alternating current, which can be integrated into direct current and used as a protective current for metals. The negative electrode is connected to the protected pipe section, and the positive electrode is connected to the auxiliary anode. A current loop is formed through the electrolyte environment in the pipeline, thereby avoiding pipeline corrosion. 2) The cellulose membrane used in the TENG structure usually has good biocompatibility and degradability, which makes it safer and more environmentally friendly in the field of drinking water. Cellulose membranes usually use natural cellulose and starch as the main raw materials, and the cost is relatively low, which helps to reduce the overall manufacturing cost of TENG. In addition, PDMS membranes have excellent performance in elasticity, thermal stability, chemical inertness and triboelectric charging ability, and are suitable for drinking water transportation, which may need to withstand mechanical deformation. 3) The preparation method of the present invention is simple and convenient, low-cost, and no harmful substances are produced during the production process, complying with the principle of green environmental protection; and can show better anti-corrosion effect than conventional means under the action of protective current. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional schematic diagram of the anti-corrosion layer structure of the present invention; Figure 2 It is a structural schematic diagram of the annular steel pipe interface of the present invention; Figure 3The short-circuit current of the PDMS membrane changes with time; Figure 4 The open circuit voltage of the PDMS membrane changes with time; In the figure: 1. annular groove; 2. steel pipe; 3. anode metal layer; 4. CNF membrane; 5. PDMS membrane; 6. copper foil contact sheet. DETAILED DESCRIPTION

[0015] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but the protection scope of the present invention is not limited thereto.

[0016] like Figure 1 and Figure 2 As shown, a hydraulic self-driven anti-corrosion layer structure at an annular steel pipe interface, an annular groove 1 is provided in the pipe wall at the annular steel pipe interface, the anti-corrosion layer structure is provided at the annular groove 1, the length of the anti-corrosion layer structure at each annular steel pipe interface is not less than 50 mm, the middle of the anti-corrosion layer structure is embedded in the annular groove 1, and the lengths of the annular grooves 1 extending from both ends are equal, the anti-corrosion layer structure includes an anode metal layer 3 provided on the outer surface of the steel pipe 2, a CNF film 4 as the positive electrode of the nano-friction generator and a PDMS film 5 as the negative electrode of the nano-friction generator, which are sequentially provided on the inner surface of the steel pipe 2, and a CNF film 4 is provided inside The wire is connected to the copper foil contact sheet 6 in the anode metal layer 3, and a wire is arranged on the inner side of the PDMS membrane 5 to connect to the copper foil contact sheet 6 in the steel pipe 2. A chemical medium filling layer is also arranged between the anode metal layer 3 and the steel pipe 2. The composition of the chemical medium filling layer is 80% calcium sulfate, 15% bentonite and 5% sodium sulfate by mass fraction. The outer surface area of ​​the chemical medium filling layer is slightly larger than the inner surface area of ​​the anode metal layer 3. The material of the anode metal layer 3 is AZ31B high-efficiency aluminum alloy, the thickness of the PDMS membrane 5 is 0.4-0.60 mm, the thickness of the CNF membrane 4 is 0.3-0.50 mm, the thickness of the anode metal layer 3 is 25-35 mm, and the adhesive material between the CNF membrane 4 and the anode metal layer 3 is low-whitening metal glue.

[0017] Example 1 In this embodiment, the specific steps for testing the short-circuit current of the PDMS membrane material are as follows: (1) A polymethyl methacrylate substrate was used as the supporting layer, a copper foil with a thickness of 0.1 mm (bottom copper electrode) was pasted on the polymethyl methacrylate substrate, and a PDMS film was pasted on the copper foil.

[0018] (2) Attach another 3 mm wide and 0.1 mm thick copper foil (top copper electrode) to the membrane surface. Use a peristaltic pump to drip liquid onto the membrane at a certain flow rate.

[0019] (3) An electrometer (Keithley 6514) was used to measure the short-circuit current by connecting two electrodes separately.

[0020] Example 2 In this embodiment, the specific steps for testing the open circuit voltage of the PDMS membrane material are as follows: (1) A polymethyl methacrylate substrate was used as the supporting layer, a copper foil with a thickness of 0.1 mm (bottom copper electrode) was pasted on the polymethyl methacrylate substrate, and a PDMS film was pasted on the copper foil.

[0021] (2) Attach another 3 mm wide and 0.1 mm thick copper foil (top copper electrode) to the membrane surface. Use a peristaltic pump to drip liquid onto the membrane at a certain flow rate.

[0022] (3) Use an electrometer (Keithley 6514) to connect the two electrodes to measure the open circuit voltage.

[0023] The short-circuit current and open-circuit voltage measurement tests were performed according to Example 1 and Example 2. The test results are shown in Figure 3 and Figure 4 As shown. By observing Example 1, it can be found that as time changes, the short-circuit current of the PDMS membrane fluctuates slightly within the experimental time of 200 s, and stabilizes at 0.8-0.9 A. By observing Example 2, it can be found that as time changes, the open-circuit voltage of the PDMS membrane fluctuates slightly within 200 s, and stabilizes at 17.0-17.2 A.

[0024] It can be seen that the current and voltage generated by this PDMS membrane are relatively stable, and its current size is sufficient to serve as a protective current. It can effectively prevent pipeline corrosion and inhibit scale formation by combining an external power cathodic protection with a hydraulic self-driving system.

Claims

1. A hydraulic self-driven anti-corrosion layer structure at an annular steel pipe interface, wherein an annular groove (1) is provided in the pipe wall at the annular steel pipe interface, characterized in that: The anti-corrosion layer structure is arranged at the annular groove (1), comprising an anode metal layer (3) arranged on the outer surface of the steel pipe (2), a CNF film (4) as the positive electrode of the nano friction generator and a PDMS film (5) as the negative electrode of the nano friction generator, which are arranged in sequence on the inner surface of the steel pipe (2); a wire is arranged on the inner side of the CNF film (4) to be connected to a copper foil contact sheet (6) in the anode metal layer (3); and a wire is arranged on the inner side of the PDMS film (5) to be connected to a copper foil contact sheet (6) in the steel pipe (2).

2. A hydraulic self-driven anti-corrosion layer structure at the annular steel pipe interface as claimed in claim 1, characterized in that: A chemical medium filling layer is also provided between the anode metal layer (3) and the steel pipe (2), wherein the composition of the chemical medium filling layer is 80% calcium sulfate, 15% bentonite and 5% sodium sulfate in terms of mass fraction.

3. A hydraulic self-driven anti-corrosion layer structure at the annular steel pipe interface as claimed in claim 1, characterized in that: The length of the anti-corrosion layer structure at each annular steel pipe interface is not less than 50 mm, the middle of the anti-corrosion layer structure is embedded in the annular groove (1), and the lengths of the two ends extending out of the annular groove (1) are equal.

4. A hydraulic self-driven anti-corrosion layer structure at the annular steel pipe interface as claimed in claim 2, characterized in that: The outer surface area of ​​the chemical medium filling layer is slightly larger than the inner surface area of ​​the anode metal layer (3).

5. The hydraulic self-driven anti-corrosion layer structure at the annular steel pipe interface as claimed in claim 1 is characterized in that: The material of the anode metal layer (3) is AZ31B high-efficiency aluminum alloy.

6. The hydraulic self-driven anti-corrosion layer structure at the annular steel pipe interface as claimed in claim 1, characterized in that: The thickness of the PDMS film (5) is 0.4-0.60 mm, the thickness of the CNF film (4) is 0.3-0.50 mm, and the thickness of the anode metal layer (3) is 25-35 mm.

7. The hydraulic self-driven anti-corrosion layer structure at the annular steel pipe interface as claimed in claim 1, characterized in that: The adhesive material between the CNF membrane (4) and the anode metal layer (3) is low-whitening metal glue.

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