Multi-layer gradient composite polyethylene lining hose and microwave triggering repairing method thereof

Abstract

The invention discloses a multi-layer gradient composite polyethylene lining hose and a microwave triggering repairing method thereof, the multi-layer gradient composite polyethylene lining hose comprises a self-repairing functional layer, a reinforcing framework layer, an interface bonding layer and an outer protective layer which are sequentially compounded from inside to outside, and the invention relates to the technical field of pipeline repairing. According to the multi-layer gradient composite polyethylene lining hose and the microwave triggering repairing method thereof, through combination of a multi-layer gradient composite structure (a self-repairing layer, a reinforcing framework and a gradient interface) and a microwave triggering repairing technology, three major breakthroughs are achieved: 1) the service life of a pipeline is prolonged to 50 years (the self-repairing efficiency is greater than or equal to 85%); (2) the repairing efficiency is improved by 3 times (DN1000 pipe is less than or equal to 8 hours), (3) the energy consumption is reduced by 70% (microwave directional curing), an intelligent monitoring system (optical fiber sensing and AI analysis) ensures the construction precision (the gap is less than or equal to 2 mm), high strength (the ring stiffness is SN12 grade), low emission (the carbon emission is reduced by 65%) and wide applicability (DN300-DN3000) are achieved, and a traditional pipeline repairing mode is thoroughly innovated.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline repair, and particularly to a multi-layer gradient composite polyethylene lining hose and a microwave-triggered repair method therefor. Background Art

[0002] Water supply pipelines are important infrastructure of cities, undertaking heavy responsibilities for the environment, resources, living and industrial needs, and social development. With the rapid development of urbanization and industrialization in China, after 15 to 30 years of operation of the early-built water supply pipe networks, a large number of water supply pipelines have cracks, breakages, pipe joint misalignments, or internal corrosion, posing great potential safety hazards to residents' lives and industrial production.

[0003] After retrieval, the patent number is CN105257947A, specifically a construction method for inverting and lining large-diameter pipelines. It uses a new material for inverting and lining large-diameter pipelines to replace the original reinforced concrete secondary structure. This method involves sending a fiber-reinforced composite hose impregnated with resin into the pipeline by air pressure or water pressure, causing the resin-impregnated lining hose to adhere to the inner wall of the shield segment, and then curing to form an anti-seepage, anti-corrosion, and good mechanical property lining structure. It includes the following construction steps: 1. Pipeline excavation and primary support construction; 2. Pipeline inner wall treatment; 3. Lining hose impregnation treatment; 4. Lining hose inversion operation; 5. Curing and forming; 6. End treatment; 7. Finished product inspection and acceptance. Using this method for lining structure construction not only has high efficiency, long anti-corrosion time, but also greatly increases the water passing section of the pipeline compared with the traditional concrete secondary structure; The patent number CN107956933A was also retrieved, specifically a composite lining hose for trenchless pipeline repair and its sewing method. The composite lining hose is composed of a fabric base layer, a reinforcement layer, and an anti-seepage layer, and is a tubular repair material made by overlapping and sewing up and down, and sealed with a film strip. The reinforcement layer greatly improves the tensile strength of the fabric base layer. The reinforcement layer forms a sandwich structure under the coverage of the fabric base layer and constitutes a composite material with the anti-seepage layer, having the characteristics of good flexibility, high strength, environmental friendliness, excellent load-bearing capacity, and corrosion resistance, and is suitable for trenchless construction to repair damaged pipelines; Retrieve patent number CN105257948A again. Specifically, it is a turnover repair method for a room-temperature curable inner lining and its turnover device, which is completed through the mutual cooperation of a turnover machine, a leveling machine, and an air compressor. The turnover machine is provided with a feed inlet, a discharge outlet, and a guiding cylinder. The repair method includes the following steps: dredging and pre-treating the pipeline to be repaired; preparing a natural curable resin and filling it into a prefabricated hose; using the cooperation of the leveling machine and the turnover machine to wind the inner lining resin hose; using the cooperation of the turnover machine and the air compressor to pressurize and turnover the inner lining resin hose; using the air compressor to pressurize and bond the hose and stabilize the curing of the inner lining hose; end treatment. The turnover repair method for a room-temperature curable inner lining and its turnover device of the present invention use room-temperature resin to be pressurized and cured at room temperature through a sealed guiding cylinder, simplify the on-site construction process flow, improve the construction efficiency of pipeline repair, and can implement the turnover method repair construction in a narrow site without a turnover tower, reduce traffic pressure, and increase the application range of trenchless inner lining technology.

[0004] The polyethylene inner lining hose in the above patent number CN105257947A has problems such as low interfacial bonding strength and poor impact resistance; the repair technology in patent number CN107956933A mostly relies on thermosetting resin, requires complex heating equipment and high energy consumption; the reinforcing layer in patent number CN105257948A uses a single fiber, making it difficult to balance flexibility and strength. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a multi-layer gradient composite polyethylene inner lining hose and its microwave-triggered repair method, which solves the problems of traditional polyethylene inner lining hoses such as low interfacial bonding strength and poor impact resistance, as well as the repair technology mostly relying on thermosetting resin, requiring complex heating equipment and high energy consumption. In addition, the traditional reinforcing layer uses a single fiber, making it difficult to balance flexibility and strength.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: A multi-layer gradient composite polyethylene inner lining hose, including the following layer structures sequentially compounded from the inside to the outside: Self-repairing functional layer, made of a blend of modified ultra-high molecular weight polyethylene (UHMWPE) and thermoplastic polyurethane elastomer (TPU), with a thickness of 0.5 - 1.2 mm. Among them, the modified UHMWPE contains 8% by mass of nano-silica particles (D50 = 35 nm), and the addition amount of silane coupling agent KH550 is 3% of the mass of the nano-particles; Reinforcing skeleton layer, a grid structure formed by three-dimensional orthogonal weaving of polyester filaments and basalt fibers, with a grid density of 10 - 20 meshes, and the fiber surface is coated with epoxy resin prepreg; The interface bonding layer is a gradient transition layer formed by co-extruding high-density polyethylene (HDPE) and polyethylene grafted with maleic anhydride (PE-g-MAH), with a thickness of 0.3 - 0.8 mm; The outer protective layer is made of a fluoropolymer coating with a thickness of 0.1 - 0.5 mm and a micro-nano composite hydrophobic structure on the surface.

[0007] Preferably, the particle size of the nano-silica particles in the self-healing functional layer 1 is 20 - 50 nm, and they are surface-modified with a silane coupling agent.

[0008] Preferably, the diameter of the basalt fiber monofilaments in the reinforcing skeleton layer 2 is 8 - 15 μm, the tensile strength is ≥3000 MPa, and the weaving angle is 45° ± 5°.

[0009] Preferably, the mass ratio of high-density polyethylene (HDPE) to polyethylene grafted with maleic anhydride (PE-g-MAH) in the interface bonding layer 3 is 3:1, and the co-extrusion temperature is 190 - 220 °C.

[0010] The present invention also discloses a manufacturing method of a multi-layer gradient composite polyethylene inner-lined hose, including the following steps: Step S1 (preparation of the self-healing functional layer): Mix KH550-modified nano-silica (addition amount 8%) and UHMWPE powder in a high-speed mixer at 80 °C for 10 min, with a mixing speed of 800 r / min and a mixing mass ratio of 1:9; Add TPU particles and melt-blend and pelletize them through a twin-screw extruder at 210 - 230 °C, with a screw length-diameter ratio of 40:1 and a speed of 200 r / min; Use a casting film machine to prepare a film with a thickness of 0.5 - 1.2 mm at 180 °C, and control the temperature of the cooling roller at 25 ± 2 °C; Step S2 (preparation of the reinforcing skeleton layer): Heat-treat the basalt fibers at 300 °C for 30 min to remove the surface sizing agent; Use a three-dimensional loom for orthogonal weaving, with the warp yarn being basalt fiber and the weft yarn being polyester filament, and the weaving speed being 5 - 8 m / min; Spray the epoxy resin prepreg on the surface of the woven skeleton and pre-cure it in an 80 °C oven for 30 min; Step S3 (composite of the interface bonding layer): Dry the HDPE and PE-g-MAH particles until the moisture content ≤0.02%; Synchronously composite them with the reinforcing skeleton layer through a twin-screw co-extrusion die head at 195 °C, with the die head pressure of 8 - 12 MPa; Step S4 (forming of the outer protective layer): Treat the surface of the interface bonding layer with a plasma cleaner (power 1000W, argon gas flow rate 20L / min) for 30s; Deposit a PVDF / CNTs composite coating through an electrospinning process, with a voltage of 15kV and a receiving distance of 15cm; Use a femtosecond laser (wavelength 1030nm, pulse width 300fs) to machine a micro-pit array on the coating surface; Step S5 (pipe forming): Form the multi-layer composite sheet through a spiral winding machine, with an overlapping width of 10 - 15mm; Weld the overlapping area with a fiber laser welding machine (wavelength 1070nm), with a welding power of 400W, a scanning speed of 15mm / s, and the shielding gas being nitrogen (purity ≥99.99%).

[0011] Preferably, in step S5, the accuracy of the tension control system of the spiral winding machine is ±0.5N, the winding angle is 55° - 65°, and the roundness error of the pipe is ≤0.5%.

[0012] The present invention also discloses a microwave-triggered repair method for a water supply pipeline with a multi-layer gradient composite polyethylene inner lining hose, including the following steps: Step A (pipe pretreatment): Excavate working wells at both ends of the pipeline to be repaired, with the well spacing ≤50m; Clean the inner wall of the pipeline with a high-pressure water jet system (pressure ≥250MPa) until the surface roughness Ra ≤6.3μm; Conduct CCTV inspection through a pipeline robot, mark the damaged positions, and generate a three-dimensional point cloud model; Step B (hose impregnation): Place the inner lining hose in a vacuum impregnation tank, evacuate to -0.095MPa and hold for 20min; Inject a repair liquid containing microcapsule-type epoxy resin, with the microcapsule wall thickness of 2 - 5μm and the capsule core containing bisphenol F epoxy resin and methyltetrahydrophthalic anhydride curing agent, with a mass ratio of 100:85; Apply a gas pressure of 0.3 - 0.5MPa to force the repair liquid to penetrate into the pores of the hose, with an impregnation time of 30 - 60min; Step C (inversion construction) Fix one end of the impregnated hose on the flange of the inversion device, and connect the other end to a diameter compensator; Introduce compressed air to gradually invert the hose, control the air pressure at 0.15 - 0.25MPa, and the inversion speed at 0.8 - 1.2m / min; Real-time monitor the hose fitting degree through a distributed optical fiber sensor to ensure that the gap with the old pipe wall is ≤2mm; Step D (Microwave-triggered Repair and Curing): Use a microwave emission array (frequency 2.45 GHz, power density 5 - 10 W / cm²) to scan along the axial direction of the pipeline; Control the microwave radiation to raise the temperature of the repair area to 80 - 100 °C, trigger the rupture of the microcapsules and release the resin; Maintain the temperature for 1 - 2 h to complete curing, and finally introduce cooling water to lower the temperature below 40 °C.

[0013] Preferably, in step D, the microwave emission array is composed of 16 magnetron units, and the phase controller focuses the microwave energy on the area where the gap between the pipe walls > 1 mm, with a focusing accuracy of ±5 cm.

[0014] Preferably, 0.1% - 0.5% of carbon nanotubes are added to the repair fluid as a microwave absorption enhancer, and the storage stability of the microcapsules at 25 °C ≥ 6 months The present invention provides a multi-layer gradient composite polyethylene lined hose and its microwave-triggered repair method. Compared with the prior art, it has the following beneficial effects: (1) This multi-layer gradient composite polyethylene lined hose and its microwave-triggered repair method, through the combination of a multi-layer gradient composite structure (self-repair layer + reinforcement skeleton + gradient interface) and microwave-triggered microwave-triggered repair technology, achieve three major breakthroughs: 1) The pipeline life is extended to 50 years (self-repair efficiency ≥ 85%); 2) The repair efficiency is increased by 3 times (for DN1000 pipe ≤ 8 hours); 3) The energy consumption is reduced by 70% (microwave directional curing). Its intelligent monitoring system (optical fiber sensing + AI analysis) ensures the construction accuracy (gap ≤ 2 mm), and has both high strength (ring stiffness SN12 level), low emissions (carbon emissions reduced by 65%) and wide applicability (DN300 - DN3000), completely revolutionizing the traditional pipeline repair mode. Brief Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram of the polyethylene lined hose of the present invention; Figure 2 It is a schematic diagram of the composition structure of the polyethylene lined hose of the present invention; Figure 3 It is a flowchart of the method for repairing a water supply pipeline of the present invention; Figure 4 It is a schematic structural diagram of the polyethylene lined hose of the present invention entering the water supply pipeline; Figure 5 It is a schematic cross-sectional structural diagram of the repaired water supply pipeline of the present invention.

[0016] In the figure: 1, self-repair functional layer; 2, reinforcement skeleton layer; 3, interface adhesion layer; 4, outer protection layer. Detailed Embodiments

[0017] The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0018] Please refer to Figure 1-2 , the embodiments of the present invention provide a technical solution: a multi-layer gradient composite polyethylene inner liner hose, including the following layer structures sequentially compounded from the inside to the outside: Self-healing functional layer 1; made of a blend of modified ultra-high molecular weight polyethylene (UHMWPE) and thermoplastic polyurethane elastomer (TPU) in a mass ratio of 7:3, with a thickness of 0.5-1.2 mm, wherein the modified UHMWPE contains 5%-10% by mass of nano-silica particles, and the nano-silica particles are surface-modified by γ-aminopropyltriethoxysilane (KH550); Reinforcing skeleton layer 2: a grid structure formed by three-dimensional orthogonal weaving of polyester filaments and basalt fibers, with a grid density of 10-20 meshes, wherein the single filament diameter of basalt fibers is 8-15 μm, the tensile strength ≥ 3000 MPa, the single filament linear density of polyester filaments is 500-800 D, the weaving angle is 45° ± 5°, and the fiber surface is coated with bisphenol A epoxy resin prepreg, and the cured prepreg accounts for 15%-25% of the total mass of the reinforcing layer Interface adhesion layer 3: a gradient transition layer formed by co-extrusion of high-density polyethylene (HDPE) and maleic anhydride grafted polyethylene (PE-g-MAH) by a twin-screw extruder, with a co-extrusion temperature of 190-220 °C, a mass ratio of HDPE to PE-g-MAH of 3:1, a thickness of 0.3-0.8 mm, and a melt index (190 °C / 2.16 kg) of 0.5-1.2 g / 10 min; Outer protective layer 4: a composite coating of polyvinylidene fluoride (PVDF) and carbon nanotubes (CNTs), wherein the mass fraction of CNTs is 0.5%-2%, the thickness is 0.1-0.5 mm, the surface is laser-etched to form a micro-pit array with a period of 20-50 μm, and the contact angle ≥ 150°.

[0019] Furthermore, in the modified UHMWPE of the self-healing functional layer 1, the particle size distribution of the nano-silica particles is D50 = 35 ± 5 nm, the specific surface area ≥ 200 m² / g, and a continuous network structure is formed in the TPU phase.

[0020] Furthermore, the epoxy resin prepreg of the reinforcing skeleton layer 2 includes the following components: Bisphenol A epoxy resin (E-51): 60-75 wt%; Methyl hexahydrophthalic anhydride curing agent: 20 - 30 wt%; 2 - Ethyl - 4 - methylimidazole accelerator: 1 - 5 wt%; Silane coupling agent (KH560): 0.5 - 2 wt%.

[0021] Further, the HDPE of the interfacial adhesion layer 3 is metallocene - catalyzed polyethylene (mPE) with a density of 0.945 - 0.955 g / cm³ and a crystallinity of ≥70%; the grafting rate of the PE - g - MAH is 1.2% - 1.8%.

[0022] Further, the PVDF and CNTs composite coating of the outer protective layer 4 is prepared by the following method: Dissolve PVDF powder in N,N - dimethylacetamide (DMAc) to form a solution with a solid content of 10% - 15%; Add carboxylated CNTs, after ultrasonic dispersion for 30 - 60 min, deposit it on the surface of the interfacial adhesion layer 3 through the electrospinning process; Heat - treat at 120 - 150 °C for 1 - 2 h to form a micro - nano composite hydrophobic structure. Please refer to Figures 3-5 , the present invention also discloses a manufacturing method of a multi - layer gradient composite polyethylene - lined hose, including the following steps: Step S1 (preparation of the self - healing functional layer 1): Raw material ratio (parts by mass): Modified UHMWPE: 70 parts (containing 8% KH550 - modified nano - SiO2 with a particle size D50 = 35 nm) TPU: 30 parts Preparation steps: Ultrasonically disperse nano - SiO2 and KH550 in ethanol at a mass ratio of 100:3 for 30 min, and obtain modified nano - particles after drying at 80 °C; Mix the modified nano - particles and UHMWPE powder in a high - speed mixer at 80 °C for 10 min; Add TPU particles and melt - blend them through a twin - screw extruder (model SHJ - 36, length - diameter ratio 40:1), temperature setting: zone 1 195 °C, zone 2 210 °C, zone 3 225 °C, zone 4 230 °C, screw speed 200 r / min; Cast into a film, die head temperature 180 °C, cooling roll 25 °C, to obtain a film with a thickness of 0.8 mm.

[0023] Twin - screw extruder processing parameters Zone 1 temperature 195 °C, zone 2 210 °C, zone 3 225 °C, zone 4 230 °C; screw speed 200 r / min, torque ratio 65%.

[0024] As follows; 1) Stepwise temperature increase strategy: Gradually increase the temperature from 195°C to 230°C, which not only ensures the disentanglement of molecular chains but also avoids thermal degradation (TGA data shows that the weight loss rate is <0.5% at 240°C); 2) Barrier screw design: Set barrier ridges in the compression section to separate the unmelted solid from the melt and improve the plasticization efficiency (the production capacity is increased by 40% compared with the traditional screw); 3) Reverse thread element: Set reverse threads at L / D = 28 to form melt reflux and eliminate pressure fluctuations (the pressure fluctuation is reduced from ±15% to ±3%).

[0025] Step S2 (Preparation of the enhanced skeleton layer 2): Raw material ratio: Warp: Basalt fiber (monofilament diameter 12μm); Weft: Polyester filament (linear density 600D); Epoxy prepreg: Bisphenol A epoxy resin E-51 (70wt%), methylhexahydrophthalic anhydride (25wt%), 2-ethyl-4-methylimidazole (4wt%), KH560 (1wt%).

[0026] Preparation steps: (1) Heat-treat the basalt fiber at 300°C for 30 min to remove the sizing agent; (2) Three-dimensional orthogonal weaving (weaving density 16 meshes, weaving angle 45°); (3) After spraying the prepreg, pre-cure at 80°C for 30 min, and the resin content accounts for 20% of the mass of the enhanced layer.

[0027] Step S3 (Lamination of the interface bonding layer 3): Raw material ratio: HDPE (metallocene mPE, density 0.95 g / cm³): 75%; PE-g-MAH (grafting rate 1.5%): 25%; Preparation steps: (1) Co-extrude with a twin-screw extruder (die temperature 195°C, pressure 10 MPa) to form a gradient transition layer with a thickness of 0.5 mm.

[0028] Step S4 (Molding of the outer protective layer 4): Raw material ratio: PVDF: 98%; Carboxylated CNTs (diameter 20 nm, length 50 μm): 2%; Preparation steps: Dissolve PVDF in DMAC to form a 12% solution, add CNTs and ultrasonically disperse for 40 min; Electrospinning (voltage 15 kV, receiving distance 15 cm) to form a 0.3 mm thick coating; (3) Femtosecond laser machining of micro-pits (period 30 μm, depth 15 μm).

[0029] Step S5 (pipe forming): Form the multi-layer composite sheet by a spiral winding machine, with an overlapping width of 10 - 15 mm; Use a fiber laser welding machine (wavelength 1070 nm) to weld the overlapping area, with a welding power of 400 W, a scanning speed of 15 mm / s, and the shielding gas being nitrogen (purity ≥ 99.99%).

[0030] Preferably, in the step S5, the accuracy of the tension control system of the spiral winding machine is ±0.5 N, the winding angle is 55° - 65°, and the roundness error of the pipe is ≤0.5%.

[0031] The present invention also discloses a microwave-triggered repair method for a water supply pipeline of a multi-layer gradient composite polyethylene-lined hose, which specifically includes the following steps: Step A, pipeline pretreatment: First, excavate and support the working well to provide an equipment access passage and an operation space to ensure construction safety. Adjust the well size according to the pipe diameter (for a DN800 pipe: well length × width = 3 m × 2 m), use a backhoe excavator for excavation, synchronously install steel sheet piles (thickness 8 mm) and steel supports (spacing 1.5 m), and arrange inclination sensors and earth pressure cells to monitor the stability of the support structure in real time. Set the displacement alarm threshold to 20 mm.

[0032] High-pressure water jet cleaning: After extending the high-pressure water jet through the working well, use the kinetic energy of the ultra-high-pressure water flow (250 - 300 MPa) to peel off the attachments (rust, biofilm, etc.) on the inner wall of the pipeline.

[0033] Equipment configuration: Nozzle design: Rotating multi-hole nozzle (aperture 1.5 mm, 6 holes evenly distributed), water jet coverage angle 120°, ensuring no cleaning dead angle.

[0034] Flow control: Adjust the flow rate (80 - 100 L / min) through a variable-frequency pump to match the cleaning efficiency of different pipe diameters (the cleaning speed of a DN500 pipe ≥ 2 m / min).

[0035] Cleanliness verification: And use an endoscope for detection: A pipeline robot equipped with a 4K camera scans the inner wall, and an image analysis software (based on OpenCV) calculates the residue coverage rate (required ≤ 3%).

[0036] Surface roughness detection: Then, it is detected by a stylus roughness meter (qualified when the Ra value ≤ 6.3μm).

[0037] 3D modeling and defect location: Laser scanning: A pipeline robot equipped with LiDAR (accuracy ±1mm) is used to collect the point cloud data of the inner wall of the pipeline at a frequency of 10Hz.

[0038] Data processing: A BIM model is generated through a point cloud registration algorithm, and AI algorithms (based on YOLOv5) automatically identify defects such as cracks and corrosion pits.

[0039] Repair planning: A microwave radiation heat map is generated according to the defect distribution, and high-damage areas (such as crack-dense areas) are preferentially cured.

[0040] Step B, Hose impregnation: Vacuum impregnation system, equipment composition: Vacuum tank: Volume 5m³ (fitted for DN1200 pipe), ultimate vacuum degree -0.1MPa; Microcapsule repair fluid circulation system: Centrifugal pump (flow rate 200L / min) and filtration device (accuracy 10μm), and the hose is placed into the impregnation equipment and impregnated with the microcapsule repair fluid.

[0041] Impregnation mechanism: Vacuum pumping stage: The vacuum pump evacuates the air in the pores of the hose to form a negative pressure environment (-0.095MPa), enhancing the permeability of the repair fluid.

[0042] Pressurized penetration stage: Under a pressure of 0.4MPa, the repair fluid penetrates into the pores of the hose reinforcement layer through the dual driving forces of capillary action and pressure difference (penetration depth ≥ 2mm).

[0043] Microcapsule repair fluid design: Capsule structure: Capsule wall: Polyurethane formaldehyde resin (thickness 2 - 5μm), glass transition temperature (Tg) 120℃, microwave absorption rate 0.8dB / cm; Capsule core: Bisphenol F epoxy resin (viscosity 500cP) and methyltetrahydrophthalic anhydride curing agent (molar ratio 1:0.85).

[0044] Microcapsule preparation method: 1. Mix bisphenol F epoxy resin and curing agent in a mass ratio of 100:85, and add 0.3% carbon nanotubes; 2. Prepare the capsule wall by the interfacial polymerization method: The oil phase is isophorone diisocyanate (IPDI), and the water phase contains polyethyleneimine (PEI); 3. Form a W / O emulsion in a high-speed emulsifier (12000r / min), and react at 50℃ for 4h to generate a polyurethane formaldehyde capsule wall; 4. Obtain microcapsules by spray drying, with a particle size distribution of 20 - 50μm.

[0045] Trigger mechanism: Microwave response: Fe3O4 nanoparticles (mass fraction 2%) are doped in the capsule wall, generating eddy current thermal effect (temperature rise rate 10°C / s) under 2.45 GHz microwaves, resulting in the rupture of the capsule wall.

[0046] Chemical curing: The released epoxy resin and curing agent undergo ring-opening polymerization reaction at 80°C to form a cross-linked network (gel time 15 min).

[0047] Quality control: Glue content detection: The mass difference of the hose before and after impregnation is the absorption amount of the repair fluid (required to increase by 15% - 20%); Microcapsule distribution uniformity: The capsule density (200 - 300 capsules / mm²) is observed by scanning electron microscopy (SEM), and the CV value ≤ 15%.

[0048] Step C: Inversion construction Inversion device design: Pneumatic drive system: Air compressor: Double-stage screw type (exhaust volume 10 m³ / min, maximum pressure 0.6 MPa).

[0049] Pressure control: PID closed-loop regulation (accuracy ±0.02 MPa), dynamically adjusting the air pressure according to the feedback of the fiber optic sensor.

[0050] Diameter compensator: Structure: Elastic silicone rubber sleeve (thickness 5 mm, Shore hardness 50A), with a built-in nylon cord reinforcement layer; Function: Compensate for the pipe diameter deviation through radial deformation (±10%) during hose inversion to prevent wrinkles.

[0051] Distributed fiber optic monitoring: Sensor layout: Embed FBG optical fibers along the axial direction of the hose (spacing 1 m), and each sensor monitors the axial strain (accuracy ±5 με) and temperature (±0.5°C).

[0052] Data analysis: Strain mapping: Calculate the gap between the hose and the old pipe wall through the wavelength offset (formula: Δλ = Kε·ε + K_T·ΔT).

[0053] Explanation of the strain mapping formula Δλ: Wavelength offset of the fiber Bragg grating (pm); Kε: Strain sensitivity coefficient (1.2 pm / με); ε: Axial strain value (με); KT: Temperature sensitivity coefficient (10 pm / °C); ΔT: Temperature change amount (°C).

[0054] Adhesion evaluation: Alarm is triggered when the gap > 2 mm, and the system automatically marks the defect location.

[0055] Intelligent control strategy: Speed-pressure coupling control.

[0056] Flipping speed: Set according to the pipe diameter (for DN800 pipe: 1.0 m / min), and adjust the winch speed through the frequency converter.

[0057] Dynamic pressure regulation: When the local gap exceeds the standard, turn on the auxiliary air pump (pressure increment 0.05 MPa) for pressure compensation.

[0058] Emergency braking: If 3 sensors alarm continuously, the system will automatically stop and start reverse air extraction (to prevent over-stretching of the hose).

[0059] Fix one end of the impregnated hose on the flange of the flipping device, connect the other end to the diameter compensator, introduce compressed air to gradually flip the hose, and make the hose flip into the water supply pipe through the flipping device, and make the hose expand and fit with the inner wall of the water supply pipe through air pressure.

[0060] Step D: Microwave-triggered repair and curing Microwave radiation system: Emission array: Layout: 16 magnetrons are evenly distributed in a ring (power adjustable range 0 - 1 kW), and the phase controller adjusts the beam focusing position.

[0061] Focusing algorithm: Based on the pipeline BIM model, use beamforming technology to concentrate the energy to the area where the gap > 1 mm (focusing accuracy ±5 cm).

[0062] Temperature field regulation: Infrared thermal imaging monitoring: Real-time collect the temperature distribution on the pipeline surface and feedback it to the microwave power controller (PID regulation).

[0063] Use a microwave emission array (frequency 2.45 GHz, power density 5 - 10 W / cm²) to scan along the axial direction of the pipeline, control the microwave radiation to raise the temperature of the repair area to 80 - 100 °C, trigger the microcapsules to rupture and release the resin, maintain the temperature for 1 - 2 h to complete curing, complete the repair of the hose and the inner wall of the pipeline, and finally introduce cooling water to lower the temperature below 40 °C.

[0064] Resin curing kinetics: Reaction equation:

[0065] Curing degree monitoring: Dielectric analysis: Judge the curing stage through the change of the dielectric loss factor (tanδ) (the peak value of tanδ corresponds to the gel point); DSC test: Sampling and detecting the glass transition temperature (Tg≥90 °C means complete curing).

[0066] Through the combination of a multi-layer gradient composite structure (self-healing layer + reinforcing skeleton + gradient interface) and microwave-triggered repair technology, this invention achieves three major breakthroughs: 1) The pipeline lifespan is extended to 50 years (self-healing efficiency ≥ 85%); 2) The repair efficiency is tripled (for a DN1000 pipe, ≤ 8 hours); 3) The energy consumption is reduced by 70% (microwave directional curing). Its intelligent monitoring system (fiber optic sensing + AI analysis) ensures construction accuracy (gap ≤ 2mm), and has both high strength (ring stiffness SN12 level), low emissions (carbon emissions reduced by 65%), and wide applicability, completely revolutionizing the traditional pipeline repair mode.

[0067] The performance test data is as follows in the table; Performance Test and Verification 1. Interface Bonding Strength Test Standard basis: ASTM D3164 "Test Method for Tensile Lap Shear Strength of Adhesives"; Specimen preparation: Bond the inner lining hose and steel plate (Q235) through the interface bonding layer, with a lap area of 25×12.5mm; Test conditions: Universal testing machine (Instron 5967), tensile rate 1.5mm / min; Result: The average shear strength is 12.3MPa (the traditional HDPE layer in the control group is 5.8MPa).

[0068] 2. Self-healing Efficiency Test Method: Pre-make a 10mm long through crack in the self-healing layer with a blade; Microwave irradiation (2.45GHz, 800W) for 120 seconds; (3) Measure the change in crack width with a metallurgical microscope and calculate the closure rate.

[0069] Calculation formula: ; where W0 = initial crack width (200μm), W1 = width after repair; Result: The average repair efficiency is 87.6% (data from three experiments: 86.2%, 88.5%, 88.1%).

[0070] 3. Pipeline Lifespan Assessment Accelerated aging test: Based on ISO 9080 "Test Method for Chemical Resistance of Plastic Pipe Systems"; Conditions: Immersed in 10% H2SO4 solution at 80°C for 1000 hours; (3) Result: The ring stiffness retention rate is 92.3%, and there is no delamination phenomenon (the retention rate of the ordinary PE pipe in the control group is 68.5%); Basis for calculation: extrapolate the Arrhenius equation to the operating environment at 25°C, and the predicted lifespan > 50 years.

[0071] 4. Energy consumption comparison Test conditions: repair 100 meters of DN800 pipeline; Traditional thermal curing method: gas heating (calorific value 35 MJ / m³), energy consumption record is 3250 MJ; Microwave curing of this technology: power consumption (conversion efficiency 85%), measured energy consumption 892 MJ.

[0072] Energy-saving calculation: .

[0073] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0074] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-layer gradient composite polyethylene lined hose, characterized in that, It includes the following layer structures that are compounded successively from the inside to the outside: Self-healing functional layer (1), which is made by blending modified ultra-high molecular weight polyethylene (UHMWPE) and thermoplastic polyurethane elastomer (TPU), with a thickness of 0.5 - 1.2 mm. The modified UHMWPE contains 5% - 10% by mass of nano-silica particles; Reinforcing skeleton layer (2), which is a grid structure formed by three-dimensional orthogonal weaving of polyester filaments and basalt fibers, with a grid density of 10 - 20 meshes, and the fiber surface is coated with epoxy resin prepreg; Interface bonding layer (3), which is a gradient transition layer formed by co-extruding high-density polyethylene (HDPE) and maleic anhydride grafted polyethylene (PE-g-MAH), with a thickness of 0.3 - 0.8 mm; Outer protective layer (4), which uses a fluoropolymer coating, with a thickness of 0.1 - 0.5 mm, and has a micro-nano composite hydrophobic structure on the surface.

2. The multi-layer gradient composite polyethylene-lined hose according to claim 1, wherein: In the self-healing functional layer (1), the nano-silica particles have a particle size of 20 - 50 nm and are surface-modified with a silane coupling agent.

3. The multi-layer gradient composite polyethylene lined hose according to claim 1, wherein: The single filament diameter of the basalt fibers in the reinforcing skeleton layer (2) is 8 - 15 μm, the tensile strength is ≥3000 MPa, and the weaving angle is 45° ± 5°.

4. A multi-layer gradient composite polyethylene-lined hose according to claim 1, characterized in that: The mass ratio of high-density polyethylene (HDPE) to maleic anhydride grafted polyethylene (PE-g-MAH) in the interface bonding layer (3) is 3:1, and the co-extrusion temperature is 190 - 220 °C.

5. A microwave-triggered repair method for the multi-layer gradient composite polyethylene-lined hose according to any one of claims 1-4, characterized in that, It includes the following steps: Step A: Open working wells at both ends of the pipeline to be repaired, and use high-pressure water jet to clean the inner wall of the pipeline; Step B: Immerse the lining hose in a repair liquid containing microcapsule-type epoxy resin. The microcapsules have a particle size of 50 - 200 μm, the capsule wall is polyurea formaldehyde resin, and the capsule core is a two-component epoxy resin and a curing agent; Step C: Use a pneumatic inversion device to send the impregnated hose into the pipeline, control the pressure to be 0.1 - 0.3 MPa, and make the hose expand and fit the old pipe wall; Step D: Trigger the rupture of the microcapsules by microwave radiation with a frequency of 2.45 GHz and a power of 500 - 1000 W, release the resin and cure it to form a microwave-triggered repair interface.

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