An underwater gas storage steel lining weld inspection and repair system and repair method

Abstract

This invention provides an inspection and repair system and method for weld seams in the steel lining of a subsea gas storage facility, belonging to the field of safety monitoring and maintenance technology for large-scale physical energy storage facilities. It includes an inspection and repair robot and control components. The inspection and repair robot resides on the inner wall of the steel lining of the subsea gas storage facility and includes a magnetic wheel chassis, a repair robotic arm, and an acoustic array detection and computing module. The end of the repair robotic arm integrates a high-pressure injection gun for leak repair material. The control components include a control and material supply center deployed outside the subsea gas storage facility, an intelligent servo reel transceiver mechanism, and a composite umbilical cable connecting the control and material supply center and the inspection and repair robot. The composite umbilical cable passes through the steel lining of the subsea gas storage facility and is wound around the intelligent servo reel transceiver mechanism. It enables real-time weld seam inspection without shutdown, precise leak location based on a rigorous mathematical model, and high-pressure in-situ repair.

Description

Technical Field

[0001] This invention relates to the field of safety monitoring and maintenance technology for large-scale physical energy storage facilities, and in particular to an inspection and repair system and method for the welded seams of steel linings in subsea gas storage facilities. Background Technology

[0002] With the transformation of the global energy structure, the grid connection rate of renewable energy sources such as offshore wind power and solar photovoltaic is constantly increasing. Offshore wind power resources are abundant and have high utilization hours, while solar energy is widely distributed and has huge development potential, but their output is subject to significant intermittency and fluctuation. To solve this problem, large-scale long-term energy storage technology has become crucial. Advanced compressed air energy storage has become a highly promising physical energy storage technology due to its advantages such as large capacity, long lifespan, and environmental friendliness. In compressed air energy storage systems, subsea artificial gas storage facilities are often used as high-pressure gas storage facilities, and their near-shore advantage allows for on-site integration with offshore wind farms. To ensure that seawater does not seep in and high-pressure air does not leak out, the inner wall of the gas storage facility is usually lined with a sealing layer, among which steel lining structures are widely used due to their excellent mechanical properties and absolute impermeability.

[0003] The steel lining of subsea gas storage facilities is mainly constructed by welding steel plates. Due to factors such as the welding environment and manual operation, initial defects such as porosity, slag inclusions, or incomplete penetration are unavoidable inside the welds. During operation, under frequent alternating loads, these defects can easily propagate into cracks, seriously threatening the safety of the gas storage facility. Currently, the detection and repair of weld defects mostly involve manual inspection and leak repair using ultrasonic or radiographic testing equipment after the gas storage facility has been completely depressurized and shut down, or the use of miniature robots to carry repair materials.

[0004] Existing inspection and repair methods have many shortcomings. Manual inspection requires depressurization and shutdown, which results in significant economic losses, and the depressurization and cooling process causes severe fatigue impact on the steel lining. Conventional flaw detection equipment is bulky and cannot achieve efficient full-coverage scanning or accurate defect location in confined spaces. Under pressure conditions of 10-20 MPa, repair materials are blown away by the high-pressure airflow before they have cured, and arc welding poses serious safety hazards and can easily lead to secondary thermal damage to the base material. Ordinary micro-robots are limited by the amount of batteries and repair materials they can carry, making it impossible to complete large-area, multi-point repairs, and frequent entry and exit for resupply is difficult to achieve in a closed, high-pressure environment. Summary of the Invention

[0005] This invention provides an inspection and repair system and method for weld seams of steel linings in subsea gas storage facilities. It addresses the pain points of existing subsea gas storage facility steel lining damage and leakage repair, enabling real-time weld seam inspection without shutting down the system, precise leak location based on a rigorous mathematical model, and high-pressure in-situ repair. The technical solution is as follows: In a first aspect, embodiments of the present invention provide an inspection and repair system for welded seams of steel linings in subsea gas storage facilities, comprising: an inspection and repair robot and control components. The inspection and repair robot is stationed on the inner wall of the steel lining of the subsea gas storage facility. It includes a magnetic wheel chassis and a repair robotic arm and an acoustic array detection and calculation module set on the magnetic wheel chassis. The end of the repair robotic arm is integrated with a high-pressure injection gun for leak repair material. The acoustic array detection and calculation module is used to capture broadband sound waves and turbulent high-frequency noise generated by high-pressure gas leakage for sound source localization and monitoring. The control components include a control and material supply center deployed outside the subsea gas storage facility, an intelligent servo reel transceiver mechanism, and a composite umbilical cable connecting the control and material supply center and the inspection and repair robot. The composite umbilical cable is threaded through the steel lining of the subsea gas storage facility and wound around the intelligent servo reel transceiver mechanism. The intelligent servo reel transceiver mechanism is used to release or tighten the composite umbilical cable according to the speed and displacement signals fed back by the inspection and repair robot.

[0006] Optionally, the composite umbilical cable integrates a high-voltage transmission line core, a communication optical fiber, and a material delivery hose. The control and material supply center is electrically connected to the inspection and repair robot through the high-voltage transmission line core, communicates with the acoustic array detection and computing module through the communication optical fiber, and is connected to the high-pressure injection gun for the leak repair material through the material delivery hose.

[0007] Optionally, the control and material supply center stores a leak-sealing material, which is a pressure-sensitive shear-thickening-liquid metal composite material, comprising a shear-thickening fluid, gallium-based liquid metal microdroplets doped and distributed in the shear-thickening fluid, and magnetic nanoparticles and thermosetting resin microcapsules.

[0008] Optionally, the end of the repair robotic arm is also equipped with a high-pressure micro-water jet cleaning nozzle and a targeted electromagnetic induction heating platform, wherein an infrared temperature sensor and electrode contact points are integrated on the targeted electromagnetic induction heating platform.

[0009] Optionally, the conveying hose is a PTFE high-pressure conveying hose reinforced with Kevlar fiber braiding, and the composite umbilical cable is covered with a polyurethane sheath.

[0010] Optionally, the magnetic chuck chassis is a variable curvature magnetic chuck chassis employing a Halbach array permanent magnet wheel system.

[0011] Optionally, the acoustic array detection and calculation module is located at the front end of the magnetic wheel system chassis and includes a uniform circular array or spherical array composed of multiple high-frequency broadband ultrasonic microphones.

[0012] Secondly, embodiments of the present invention provide a repair method based on the inspection and repair system for the steel lining welds of a subsea gas storage facility described in the first aspect, comprising: Step 1: The inspection and repair robot patrols along the weld seams on the inner wall of the steel lining of the subsea gas storage facility. The control and material supply center supplies repair materials and power through the composite umbilical cable and uses the intelligent servo reel transceiver mechanism to reel in and out the composite umbilical cable. Step 2: Utilize the acoustic array detection and calculation module to continuously monitor and locate the leak point, and instruct the inspection and repair robot to move directly above the leak point; Step 3: Use the high-pressure injection gun to fill and seal the crack at the leak point with the sealant, and use the acoustic array detection and calculation module to monitor in real time until the broadband sound waves and turbulent high-frequency noise generated by the high-pressure gas leak disappear.

[0013] Optionally, the acoustic array detection and calculation module includes a uniform circular array or spherical array composed of multiple high-frequency broadband ultrasonic microphones, and step two includes: Establish a spatial coordinate and signal propagation model; Calculate the time difference of arrival of the sound wave from the leak point to any two of the high-frequency broadband ultrasonic microphones; Based on SRP-PHAT spatial spectrum estimation and extreme value tracking, millimeter-level precise location of cracks at the leakage point is achieved.

[0014] Optionally, the end of the repair robotic arm is equipped with a high-pressure micro-water jet cleaning nozzle and a targeted electromagnetic induction heating platform. The targeted electromagnetic induction heating platform integrates an infrared temperature sensor and electrode contact points. Step three includes: The area where the crack is located is cleaned using the high-pressure micro-water jet cleaning nozzle. The leak-sealing material is injected into the crack at the leak point using a high-pressure injection gun to form a repair area. An alternating magnetic field is applied using the targeted electromagnetic induction heating gimbal, the surface temperature of the repair area is monitored using the infrared temperature sensor, and the resistivity change of the repair material is measured using the electrode contact point. The acoustic array detection and calculation module was used to monitor the repair area to confirm that the broadband sound waves and turbulent high-frequency noise generated by the high-pressure gas leak had disappeared.

[0015] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following: The system of this invention mainly consists of two parts: an inspection and repair robot and a control component. The inspection and repair robot resides permanently on the inner wall of the steel lining of the subsea gas storage facility, acting as a terminal actuator to perform inspection and in-situ repair tasks along the weld seams of the steel lining under operating conditions without shutdown or depressurization. The control component is deployed outside the subsea gas storage facility (e.g., at the wellhead or in an external control room), providing the inspection and repair robot with power, communication links, and repair materials via a composite umbilical cable threaded through the sealed steel lining wall. This completely breaks the physical limitations of the micro-robot's built-in battery and material storage, enabling the inspection and repair robot to perform continuous inspection and repair capabilities around the clock, over large areas, and at multiple points within the massive gas storage facility.

[0016] The embodiments of this invention systematically solve the problems of huge economic losses and steel lining fatigue impact caused by the need to shut down and depressurize during traditional manual inspections. At the same time, it overcomes the shortcomings of conventional flaw detection equipment, which is bulky and difficult to efficiently cover the entire area in a confined space. It realizes continuous, unmanned inspection and precise repair of subsea gas storage facilities under pressurized operation. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the inspection and repair system for the steel lining welds of a subsea gas storage facility provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the inspection and repair robot provided in an embodiment of the present invention; Figure 3 yes Figure 2 A magnified schematic diagram of the local structure at point A; Figure 4 This is a schematic diagram of the structure of the control component provided in an embodiment of the present invention; Figure 5 This is a cross-sectional view of the composite umbilical cable provided in an embodiment of the present invention; Figure 6 This is a flowchart of the repair method provided in the embodiments of the present invention.

[0019] In the diagram: 1-Inspection and repair robot; 11-Magnetic wheel chassis; 12-Repair robotic arm; 121-High-pressure injection gun for leak repair material; 122-High-pressure micro-water jet cleaning nozzle; 123-Targeted electromagnetic induction heating gimbal; 13-Acoustic array detection and calculation module; 2-Control components; 21-Control and material supply center; 22-Intelligent servo coil transceiver mechanism; 23-Composite umbilical cable; 231-High-voltage transmission line core; 232-Communication optical fiber; 233-Material conveying hose; m-Steel lining. Detailed Implementation To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0020] refer to Figures 1 to 5 This invention provides an inspection and repair system for the welded seams of the steel lining of a subsea gas storage facility. This system is applied to advanced compressed air energy storage (ACAES) subsea artificial gas storage facilities, whose internal operating pressure typically reaches 10 MPa to 20 MPa, and which must withstand alternating loads caused by frequent energy storage and release. The system mainly consists of two parts: an inspection and repair robot 1 and a control component 2. Among them, the inspection and repair robot 1 resides on the inner wall of the steel lining m of the subsea gas storage for a long time. As the terminal actuator, it completes inspection and in-situ repair tasks along the weld seam of the steel lining m under the operating conditions of no shutdown and no depressurization. The control component 2 is deployed outside the subsea gas storage (such as the wellhead or external control room). Through the composite umbilical cable 23 that runs through the sealed compartment wall of the steel lining m, it continuously provides the inspection and repair robot 1 with power, communication links and leak repair materials. This completely breaks the physical limitations of the built-in battery and hopper of the micro robot, enabling the inspection and repair robot 1 to have the ability to conduct continuous inspection and repair in the huge gas storage with all-weather, large area and multiple points.

[0021] Specifically, the inspection and repair robot 1 includes a magnetic wheel chassis 11, a repair robotic arm 12 mounted on the magnetic wheel chassis 11, and an acoustic array detection and calculation module 13. The magnetic wheel chassis 11 serves as the basis for the movement and adhesion of the inspection and repair robot 1. It overcomes its own gravity and the drag force generated by the composite umbilical cable 23 through magnetic adhesion, stably attaching to the inner wall of the steel lining and achieving omnidirectional movement along the weld direction. The repair robotic arm 12 is mounted above the magnetic wheel chassis 11 and has multiple degrees of freedom. It can precisely adjust the attitude and position of the end effector in three-dimensional space to adapt to the weld defect repair needs in different spatial orientations. The end of the repair robotic arm 12 integrates a high-pressure injection gun 121 for leak repair material. The high-pressure injection gun 121 injects leak repair material supplied externally by the control component 2 into the crack at the leak point at an injection pressure higher than the internal gas pressure of the gas storage tank, thereby overcoming the reverse impact of the high-pressure airflow and achieving in-situ sealing under pressure. The acoustic array detection and calculation module 13 is used to capture broadband sound waves and turbulent high-frequency noise generated during high-pressure gas leakage in real time, and to locate the sound source of the leak point based on the collected acoustic signals, and to continuously monitor the sound field changes during the material injection and curing stages to achieve dynamic monitoring of the repair effect.

[0022] Control component 2 includes a control and material supply center 21 deployed outside the subsea gas storage facility, an intelligent servo reel transceiver mechanism 22, and a composite umbilical cable 23 connecting the control and material supply center 21 and the inspection and repair robot 1. The control and material supply center 21 serves as the system's energy, material, and control hub, integrating units such as a high-pressure pump station, high-pressure power supply, leak repair material storage tanks, and a main control computer. It is responsible for uniformly managing the system's operational status, deciding on repair strategies, and providing a continuous supply of energy and materials. The composite umbilical cable 23 is threaded through a pre-drilled sealed cable passage on the steel lining of the subsea gas storage facility and wound around the intelligent servo reel transceiver mechanism 22. The intelligent servo reel transceiver mechanism 22 is driven by a high-precision servo motor and equipped with a tension sensor. It releases or tightens the composite umbilical cable 23 synchronously based on the speed and displacement signals fed back by the inspection and repair robot 1 in real time. When the inspection and repair robot 1 moves forward along the weld seam, the intelligent servo reel transceiver mechanism 22 actively releases the cable. When the inspection and repair robot 1 moves backward or turns, the intelligent servo reel transceiver mechanism 22 automatically winds up the excess cable. The tension control system always keeps the composite umbilical cable 23 in a slightly tensioned state, which not only prevents the cable from being dragged and worn or tangled on the inner wall of the steel lining, but also avoids generating excessive drag resistance to the movement of the inspection and repair robot 1.

[0023] Through the above structure, the embodiments of the present invention systematically solve the problems of huge economic losses and steel lining fatigue impact caused by the need to shut down and depressurize during traditional manual inspections. At the same time, it overcomes the shortcomings of conventional flaw detection equipment, which is bulky and difficult to efficiently cover the entire area in a confined space, and realizes continuous, unmanned inspection and precise repair of the subsea gas storage facility under pressurized operation.

[0024] In an optional embodiment, the composite umbilical cable 23 serves as a multifunctional composite transmission medium connecting the control and material supply center 21 and the inspection and repair robot 1. It integrates a high-voltage transmission line core 231, a communication optical fiber 232, and a material conveying hose 233. The control and material supply center 21 is electrically connected to the inspection and repair robot 1 via the high-voltage transmission line core 231 to continuously supply power to the drive motor of the magnetic chuck chassis 11, the actuator of the repair robotic arm 12, and the electronic unit of the acoustic array detection and calculation module 13, thus avoiding the problem of limited built-in battery capacity. The control and material supply center 21 is communicatively connected to the acoustic array detection and calculation module 13 via the communication optical fiber 232, enabling bidirectional data transmission with gigabit bandwidth. This allows the transmission of raw sound waves collected by the acoustic array detection and calculation module 13. Signals, positioning results, and robot pose information are transmitted back to the control and material supply center 21 in real time. It can also send control commands and repair strategies from the host computer to the inspection and repair robot 1, ensuring the real-time performance and reliability of the system's control response under long-distance transmission conditions. The control and material supply center 21 is connected to the high-pressure injection gun 121 for leak repair materials through the material delivery hose 233. The leak repair materials stored in the control and material supply center 21 are transported to the nozzle of the high-pressure injection gun 121 for injection into the cracks at the leak point by means of a high-pressure pump.

[0025] By integrating power supply, communication, and material conveying functions into the same composite umbilical cable 23, this embodiment not only simplifies the sealing structure of the cable passage and reduces the impact of steel lining openings on the structural strength of the gas storage tank, but also avoids the problem of multiple cables tangling and interfering with each other, thus improving the operational reliability of the system in the high-pressure sealed chamber on the seabed.

[0026] In an optional embodiment, the control and material supply center 21 stores a leak-sealing material, which is a pressure-sensitive shear-thickening-liquid metal composite material, comprising a shear-thickening fluid, gallium-based liquid metal microdroplets doped and distributed in the shear-thickening fluid, and magnetic nanoparticles and thermosetting resin microcapsules. The shear-thickening fluid (STF) serves as the matrix layer of the composite material, formed by uniformly dispersing nano-silica particles in polyethylene glycol. It exhibits significant shear rate-dependent rheological properties: at low shear rates (e.g., when pumped in a long-distance composite umbilical cable 23), it presents a low-viscosity liquid state with minimal flow resistance, facilitating long-distance transport; however, when the leak-sealing material is injected into the crack at the leak point by the high-pressure injection gun 121 and encounters a strong impact from a high-pressure leak gas flow of 10 MPa to 20 MPa (i.e., under extremely high shear rate conditions), the shear-thickening fluid undergoes an instantaneous phase change, its viscosity increasing tens of thousands of times, exhibiting a rigid state similar to a solid, thereby forming an initial "mechanical wedge" to seal the leak channel.

[0027] Gallium-based liquid metal droplets, doped and distributed in a shear-thickening fluid, serve as the metallurgical bonding layer of the composite material. Specifically, gallium indium tin (GaInT) liquid metal can be used. After the composite material is squeezed into the crack and fixed due to the shear-thickening effect, the gallium-based liquid metal droplets demulsify and precipitate due to changes in the internal stress of the system. They then wet and alloy with the iron-based surface of the steel lining crack, forming a dense, atomically-level metallurgical sealing interface, fundamentally ensuring the long-term stability and airtightness of the seal.

[0028] Similarly, magnetic nanoparticles and thermosetting resin microcapsules, also doped into shear-thickening fluids, serve as the curing and reinforcing layer of a composite material. The magnetic nanoparticles are preferably Fe3O4 magnetic nanoparticles, and the thermosetting resin microcapsules are preferably microcapsules containing epoxy resin. Under external triggering conditions (such as alternating magnetic field-guided heating or crack pressure), the microcapsules rupture, releasing the epoxy resin. The resin then cross-links and cures under heating to form a three-dimensional cross-linked network, which synergistically enhances the mechanical integrity and durability of the sealing structure with the magnetic nanoparticles.

[0029] In this embodiment, the pressure-sensitive shear-thickening-liquid metal composite material cleverly utilizes the destructive force (high shear force) of the leaking gas flow itself as the trigger condition for material hardening. It maintains low viscosity for easy transport during long-distance pumping within the composite umbilical cable 23, and instantly hardens to prevent splashing when it encounters the impact of the gas flow after being ejected. This completely solves the industry problem of traditional repair agents being "blown away" and failing under pressurized conditions.

[0030] In an optional embodiment, the end of the repair robotic arm 12, in addition to integrating a high-pressure injection gun 121 for the repair material, is also equipped with a high-pressure micro-water jet cleaning nozzle 122 and a targeted electromagnetic induction heating gimbal 123. The high-pressure micro-water jet cleaning nozzle 122 is used to perform non-contact cleaning of the crack and its surrounding surface by spraying high-pressure micro-water jets before the repair material is injected, removing rust, oil, and oxide layers from the weld surface to ensure a good metallurgical bonding interface between the repair material and the steel lining base material after injection. The targeted electromagnetic induction heating gimbal 123 is used to apply a controllable high-frequency alternating magnetic field above the repair area after the repair material is injected. Through electromagnetic induction, the Fe3O4 magnetic nanoparticles dispersed within the repair material generate a magnetic hysteresis effect, thereby performing non-contact, directional, and rapid heating and curing of the repair material without affecting the temperature field of the surrounding base material. This avoids the significant safety hazards and secondary thermal damage to the base material caused by traditional arc welding under pressure.

[0031] Furthermore, the targeted electromagnetic induction heating gimbal 123 integrates an infrared temperature sensor and electrode contact points. The infrared temperature sensor is used to monitor the surface temperature of the repair area in real time and non-contact during the heating process to ensure that the curing temperature is maintained within the set process range (preferably 120°C to 150°C). The electrode contact points establish an electrical connection with the outer surface of the repair material to measure the resistivity change of the repair material in real time during the cross-linking curing process. Since the resistivity of the shear thickening fluid / liquid metal / resin microcapsule composite material will show a specific change curve as the curing cross-linking reaction proceeds, the control and material supply center 21 can compare the real-time measured resistivity with the preset fully cured reference value. When the temperature rises to 120°C to 150°C and the slope of the resistivity change approaches zero, it can be determined that the resin matrix has completed cross-linking and reached permanent repair strength. At this time, the targeted electromagnetic induction heating gimbal 123 automatically reduces power and enters the furnace cooling stage to avoid the steel lining base material from generating a heat-affected zone or residual stress due to overheating.

[0032] This embodiment utilizes the resistivity of the repair material as an intrinsic sensing parameter of the curing process, replacing the traditional timed heating open-loop process. This ensures the consistency of crosslinking quality and process reliability for each in-situ repair, and significantly improves the unmanned autonomous operation level of the system in complex, closed, high-pressure underwater environments.

[0033] In an optional embodiment, the delivery hose 233 is a PTFE (polytetrafluoroethylene) high-pressure delivery hose reinforced with Kevlar fiber braiding. The PTFE material possesses excellent chemical inertness, a low coefficient of friction, and a wide temperature adaptability range, ensuring that the nano-silica particles, gallium-based liquid metal droplets, and thermosetting resin microcapsules in the leak-sealing material do not adhere to the pipe wall, undergo chemical reactions, or agglomerate during long-distance transport. The Kevlar fiber braiding layer endows the delivery hose 233 with extremely high tensile strength and resistance to internal pressure bursts, enabling it to withstand long-distance pumping of the leak-sealing material at injection pressures higher than the internal gas pressure of the gas storage tank (i.e., higher than 10 MPa to 20 MPa).

[0034] Furthermore, the composite umbilical cable 23 is externally covered with a polyurethane sheath. The polyurethane sheath has excellent wear resistance, high pressure resistance, and flexibility. It can protect the high-voltage transmission wire core 231, communication optical fiber 232, and material conveying hose 233 inside the composite umbilical cable 23 from wear, twisting, and external impact during repeated winding and unwinding. It can also ensure that the composite umbilical cable 23 as a whole has sufficient flexibility to adapt to the winding and unwinding of the intelligent servo reel transceiver mechanism 22, thereby providing physical protection for the long-term stable operation of the entire system in the subsea high-pressure gas storage facility.

[0035] In an optional embodiment, the magnetic wheel system chassis 11 is a variable curvature magnetic wheel system using a Halbach array permanent magnet wheel system. The Halbach array, through a special arrangement of the magnetization directions of the permanent magnets, can highly concentrate the magnetic flux on one side of the working surface of the wheel system (i.e., the side facing the inner wall of the steel liner), while almost canceling each other out on the other side. This significantly enhances the attraction force to the inner wall of the steel liner without increasing the total mass of the magnets, effectively overcoming the weight of the inspection and repair robot 1 itself and the dragging force exerted by the composite umbilical cable 23. The wheel system structure of the variable curvature magnetic wheel system can adapt to the curvature changes of the steel liner surface, enabling stable movement on large-scale flat steel plate areas and smooth passage through steel liner dome areas with a certain radius of curvature. This achieves strong attraction and omnidirectional movement on all directions and in all postures (including horizontal, vertical, and inverted surfaces) of the gas storage tank's inner wall, ensuring that the inspection and repair robot 1 can cover all welded areas of the gas storage tank's inner wall.

[0036] In an optional embodiment, the acoustic array detection and calculation module 13 is disposed at the front end of the magnetic wheel chassis 11, and includes a uniform circular array (UCA) or spherical array composed of multiple high-frequency broadband ultrasonic microphones. Arranging the acoustic array detection and calculation module 13 at the front end of the magnetic wheel chassis 11 facilitates its priority acquisition of the sound field in front of the inspection and repair robot 1 along its travel direction, while avoiding interference from mechanical vibrations and motor noise of the repair robotic arm 12 during operation. The multi-microphone arrangement of the uniform circular array or spherical array has advantages such as consistent phase center, uniform azimuth resolution, and good directivity to three-dimensional sound sources. It can accurately capture broadband sound waves and turbulent high-frequency noise generated by micro-leakage of high-pressure gas in complex environments with strong reverberation and high background noise inside the steel lining, providing high-quality raw signal input for subsequent precise sound source localization based on the Time Difference of Arrival (TDOA) algorithm and Steered Response Power (SRP) beamforming technology.

[0037] Furthermore, the acoustic array detection and calculation module 13 has a built-in edge computing microprocessor, which is responsible for performing real-time fast Fourier transform, cross-correlation calculation, spatial spectrum estimation and gradient extremum tracking on the acquired multi-channel acoustic signals. This avoids the time delay problem of transmitting the original signal back to the control and material supply center 21 via the communication optical fiber 232 for centralized processing, and significantly improves the system's response speed to dynamic leakage events.

[0038] refer to Figure 6 ,based on Figures 1 to 5 The aforementioned inspection and repair system for the steel lining welds of a subsea gas storage facility, as shown in this embodiment, also provides a method for repairing the steel lining welds of a subsea gas storage facility. The repair method includes the following steps: S1. The inspection and repair robot 1 patrols along the weld seam on the inner wall of the steel lining of the subsea gas storage facility. The control and material supply center 21 supplies leak repair materials and power through the composite umbilical cable 23, and the intelligent servo reel transceiver mechanism 22 retrieves and deploys the composite umbilical cable 23.

[0039] Specifically, during the execution of S1, the inspection and repair robot 1, relying on its magnetic wheel chassis 11, continuously inspects the weld path along the inner wall of the steel lining at a certain speed (e.g., 0.5 m / s). The inspection path can be automatically planned according to a preset weld path map. As the inspection and repair robot 1 moves forward, the intelligent servo reel transceiver mechanism 22 synchronously releases the composite umbilical cable 23 based on the real-time displacement and speed signals fed back by the robot, keeping it in a slightly tensioned state. Simultaneously, the control and material supply center 21 provides uninterrupted power to the robot 1 through the high-voltage transmission line core 231, and maintains the stored repair material at a preset standby pressure through the material delivery hose 233, enabling injection operations to be initiated within milliseconds after a leak is detected. This step enables the inspection and repair robot 1 to perform long-endurance, unreplenished stay, and collaborative inspection within the high-pressure gas storage tank, overcoming the technical bottleneck of traditional micro-robots being limited by battery capacity and the amount of repair material they can carry, thus preventing them from completing large-area, multi-point repairs.

[0040] S2. The acoustic array detection and calculation module 13 is used to continuously monitor and locate the leak point, and the inspection and repair robot 1 is instructed to move directly above the leak point.

[0041] Specifically, during the inspection process, multiple high-frequency broadband ultrasonic microphones in the acoustic array detection and calculation module 13 continuously collect sound field signals near the inner wall of the steel lining. When an abnormal high-frequency acoustic emission signal (i.e., broadband sound waves and turbulent high-frequency noise exceeding a preset threshold) is detected, the edge computing microprocessor immediately activates the positioning algorithm to process the collected multi-channel sound wave signals, calculate the three-dimensional coordinates of the leak source, and transmit the positioning results back to the control and material supply center 21 via the communication fiber optic cable 232. Based on this, the control and material supply center 21 issues a movement command to the inspection and repair robot 1, guiding it to move along the gradient direction of increasing sound pressure level (SPL), and finally accurately locates itself directly above the leak point, providing accurate pose reference for subsequent injection repair operations.

[0042] S3. Use the high-pressure injection gun 121 to fill and seal the cracks at the leak point with the sealing material, and use the acoustic array detection and calculation module 13 to monitor in real time until the broadband sound waves and turbulent high-frequency noise generated by the high-pressure gas leak disappear.

[0043] Specifically, after the inspection and repair robot 1 arrives directly above the leak point, the high-pressure pump station inside the control and material supply center 21 is activated. At an injection pressure higher than the internal pressure of the gas storage tank, the sealant material is delivered via the delivery hose 233 to the high-pressure injection gun 121. The high-pressure injection gun 121 injects the sealant material into the crack at the leak point in a spray manner. Upon encountering the high shear force of the high-pressure leaking airflow, the sealant material instantly undergoes shear thickening, forming an initial mechanical wedge within the crack to seal the leak channel. During the injection process, the acoustic array detection and calculation module 13 continuously monitors the sound pressure level changes near the leak point. Once the acoustic signal drops to the ambient background noise level, the crack sealing operation is considered complete. This step, by coupling the injection operation with a closed-loop acoustic feedback, achieves visualization and controllability of the pressurized in-situ repair process, fundamentally ensuring the reliability of the repair results.

[0044] Furthermore, the acoustic array detection and calculation module 13 includes a uniform circular array or spherical array composed of multiple high-frequency broadband ultrasonic microphones. The process of locating the leakage point in S2 specifically includes the following sub-steps: S21. Establish a spatial coordinate and signal propagation model.

[0045] Specifically, let the coordinate vector of the microcrack leakage point (sound source) on the steel lining of the gas storage tank in three-dimensional space be... The acoustic array detection and calculation module 13 onboard the robot contains M microphones, and the spatial coordinate vector of the i-th microphone is... Where i = 1, 2, M.

[0046] The actual spatial distance from the sound source to the i-th microphone This can be expressed by the Euclidean distance formula: Let the original sound wave signal generated by the high-pressure gas leak be s(t), and the speed of sound in the high-pressure environment of the gas storage facility be c (which needs to be corrected according to the real-time pressure and temperature inside the gas storage facility). Then the... The signal received by the microphone It can be modeled as: in, The signal attenuation coefficient is... Let be the absolute propagation time of the sound wave from the leak point to the i-th microphone. This refers to ambient background noise.

[0047] S22. Calculate the time difference of sound wave arrival from the leak point to any two high-frequency broadband ultrasonic microphones.

[0048] Since the absolute transmission time is unknown, the system eliminates the absolute time by calculating the time difference of arrival (TDOA) between any two microphones i and j. The theoretical time difference... for: Where j refers to the j-th microphone, and like i, it is a constant. s is the coordinate vector. The subscript in the text has no specific meaning.

[0049] To accurately estimate the time difference of the actual received signal in the strong reverberation environment inside the steel lining of a gas storage facility, this invention employs a phase-transform weighted generalized cross-correlation algorithm. First, the received signal... and Perform a Fast Fourier Transform (FFT) to obtain the frequency domain signal. and Where t represents time, which is the time-domain independent variable of the signal. The physical meaning of is the angular frequency corresponding to each frequency component in the acoustic emission signal.

[0050] The cross power spectral density function is defined as ,in Indicates complex conjugation.

[0051] Introducing the PHAT weighting function This is used to whiten the signal and suppress reverberation. Generalized cross-correlation function. Obtained through inverse Fourier transform: In cross-correlation function In the diagram, the horizontal axis corresponding to the peak value is the estimated time difference as actually measured. : S23. Based on SRP-PHAT spatial spectrum estimation and extreme value tracking, millimeter-level precise location of cracks at leakage points is achieved.

[0052] Traditional methods for solving hyperboloid equations based on TDOA are prone to divergence in the near field or under high noise conditions. This invention further introduces controllable response power beamforming technology. The gas storage tank wall is divided into a three-dimensional search grid, and for any assumed coordinate point p in space, its corresponding theoretical time difference is calculated. .in: and The calculation formula is the same. This represents any candidate point in the 3D search grid, calculated point by point during the localization process. This represents the leak point, which is also the actual source of acoustic emission.

[0053] Define the spatial acoustic energy spectrum function (i.e., the SRP objective function) at point p. It is the sum of the energy of the cross-correlation functions between all microphone pairs at the theoretical time difference: When the assumed point p is closer to the actual leak point At that time, the more aligned the cross-correlation peaks of each microphone pair are, the higher the spatial spectral energy. The larger the value, the greater the final three-dimensional coordinate estimate of the leak point. This is transformed into a problem of finding the global maximum of the spatial spectral function: During the inspection and repair robot 1's inspection process, the main control system performs real-time gradient calculation on E(p) to obtain the spatial spectral gradient in front of the current position. E(p). The magnetic wheel system chassis 11 automatically adjusts its direction of travel according to the gradient ascent method, and continuously approaches along the signal strength gradient (i.e., the direction in which the sound pressure level SPL gradually increases) until it reaches the extreme point of E(p), thereby achieving millimeter-level precise positioning of the cracked part of the steel lining.

[0054] Furthermore, the end of the repair robotic arm 12 is equipped with a high-pressure micro-water jet cleaning nozzle 122 and a targeted electromagnetic induction heating gimbal 123. The targeted electromagnetic induction heating gimbal 123 integrates an infrared temperature sensor and electrode contact points. The aforementioned S3 specifically includes the following sub-steps: S31. Clean the area where the crack is located using the high-pressure micro-water jet cleaning nozzle 122. Specifically, after the inspection and repair robot 1 arrives directly above the leak point, the repair robotic arm 12 first positions the high-pressure micro-water jet cleaning nozzle 122 directly above the crack at the leak point, and performs surface pretreatment on the crack and its surrounding area with a preset jet pressure and spraying time, removing rust, oxide layer, oil stains and welding slag residues attached to the surface of the steel lining weld, so that the crack surface reaches a clean state with a metallic luster, providing the necessary surface conditions for the subsequent leak repair material to form a good wetting and metallurgical bond with the steel lining base material.

[0055] S32. The high-pressure injection gun 121 is used to inject the sealant into the crack at the leak point to form a repair area. Specifically, after the surface pretreatment is completed, the repair robot arm 12 switches to the high-pressure injection gun 121, and the high-pressure pump station in the control and material supply center 21 is started. The stored pressure-sensitive shear thickening-liquid metal composite material is transported to the high-pressure injection gun 121 through the delivery hose 233, and the sealant is injected into the crack at the leak point at an injection pressure higher than the internal gas pressure of the gas storage tank (for example, for a working condition of 15.5 MPa, the injection pressure can be set to 17 MPa to 20 MPa). When the sealant encounters the high-pressure leaking gas at the crack, it undergoes a shear thickening phase transition, causing its viscosity to surge tens of thousands of times, forming an initial mechanical wedge. Simultaneously, gallium-based liquid metal droplets in the sealant break down and precipitate, wetting and alloying with the steel-lined iron base surface to form a dense atomic-level metallurgical sealing interface. The dispersed Fe3O4 magnetic nanoparticles and thermosetting resin microcapsules in the material uniformly fill the interior and surface of the crack, forming a repair area to be cured.

[0056] Furthermore, during the injection of the sealing material, this embodiment preferably employs an adaptive adjustment strategy for injection pressure based primarily on acoustic signals to enhance the intelligence level of the injection process. Specifically, the acoustic array detection and calculation module 13 continuously collects the sound pressure level (SPL) at the leak point and defines a sealing degree index. ,in To repair the initial leak sound pressure level detected before the process began, The current leak sound pressure level detected in real time. This refers to the ambient background noise sound pressure level.

[0057] Control and Material Supply Center 21 uses the degree of blockage η as the process variable and the output pressure of the high-pressure pump station as the control and material supply center. As the manipulated variable, an adaptive fuzzy PID control law is established. The control logic is as follows: In the initial stage of injection (η<0.3), the cross-sectional area of ​​the leak is large and the airflow impact force is extremely strong. The system maintains a high injection pressure to counteract the airflow, prompting the shear-thickening fluid matrix to rapidly shear and thicken to form an initial wedge. When the sealing degree η increases to the range of 0.3≤η≤0.9, the leak channel narrows. The system dynamically reduces the injection pressure according to the SPL decrease rate to prevent overpressure injection from causing excessive material penetration into the gas storage tank or destroying the existing physical plug. When η>0.9, the acoustic signal tends to the level of ambient background noise. The system switches the injection pressure to a low-pressure holding mode to provide a stable material filling environment for subsequent metallurgical bonding and solidification.

[0058] S33. An alternating magnetic field is applied using a targeted electromagnetic induction heating gimbal 123, and the surface temperature of the repair area is monitored using an infrared temperature sensor. The resistivity change of the repair material is measured using electrode contact points. Specifically, after the repair material is injected, the repair robotic arm 12 positions the targeted electromagnetic induction heating gimbal 123 above the repair area and applies a high-frequency alternating magnetic field. The Fe3O4 magnetic nanoparticles inside the repair material generate a magnetic hysteresis heating effect under the action of the alternating magnetic field, causing the temperature of the repair area to rise rapidly to 120°C to 150°C. This causes the thermosetting resin microcapsules to rupture and release epoxy resin. The epoxy resin cross-links and cures at high temperature to form a three-dimensional network structure, thereby forming a permanent repair layer. During this heating and curing process, an infrared temperature sensor monitors the surface temperature of the repair area in real time to avoid damage to the heat-affected zone of the steel lining base material due to excessive temperature. The electrode contact point measures the resistivity change of the repair material in real time during the curing process and compares the measured value with the preset reference value for complete curing. When the temperature reaches 120°C to 150°C and the slope of the resistivity change approaches zero, it is determined that the curing reaction has been completed. Based on this, the control and material supply center 21 controls the targeted electromagnetic induction heating gimbal 123 to automatically reduce the power and switch to the furnace cooling stage.

[0059] S34. The acoustic array detection and calculation module 13 is used to monitor the repair area to confirm that the broadband sound waves and turbulent high-frequency noise generated by the high-pressure gas leak have disappeared. Specifically, after curing is completed and the area has cooled to a safe temperature, the acoustic array detection and calculation module 13 performs acoustic monitoring and verification on the repair area again. If the collected acoustic signal has stabilized and decreased to the level of the ambient background noise and no longer exhibits abnormal broadband sound waves and turbulent high-frequency noise, the in-situ repair operation is confirmed to be successfully completed; otherwise, the system will restart the repair process from sub-steps 3.1 to 3.3 until the acoustic verification is passed. This closed-loop verification mechanism ensures the integrity and reliability of each repair task and significantly reduces the probability of repeated out-of-cabin or shutdown inspections.

[0060] As a specific application case, the inspection and repair system for the steel lining welds of the subsea gas storage facility, as described in this embodiment of the invention, was deployed in the subsea artificial chamber gas storage facility of a 100MW advanced compressed air energy storage power station. The current operating pressure of the gas storage facility is 15.5MPa. The inspection and repair robot 1, relying on the magnetic wheel chassis 11, performs routine inspections on the dome steel lining at a speed of 0.5m / s. When the inspection and repair robot 1 moves near a certain circumferential weld, the acoustic array detection and calculation module 13 captures an abnormal high-frequency acoustic emission signal. The built-in edge computing microprocessor immediately starts, performs a fast Fourier transform on the received multi-channel signals, calculates the generalized cross-correlation function Rij(τ), and constructs the spatial spectrum function E(p). Through the gradient tracking algorithm, the spatial spectrum extremum point is locked in about 0.2 seconds, guiding the inspection and repair robot 1 to move to the circumferential weld 3.2 meters ahead, where a microcrack with a length of 12mm and a width of 0.15mm is found.

[0061] Subsequently, the repair robotic arm 12 activates the high-pressure micro-water jet cleaning nozzle 122 to pre-treat the surface of the crack area. After cleaning, it switches to the high-pressure injection gun 121 for the repair material. The high-pressure pump station in the control and material supply center 21 is activated, and the pressure-sensitive shear thickening-liquid metal composite material is rapidly delivered to the high-pressure injection gun 121 through a 100-meter-long delivery hose 233. The material encounters a high shear force of 15.5 MPa airflow the moment it is injected into the crack. The shear thickening fluid matrix undergoes a phase change in about 0.1 seconds, and the viscosity surges to form a solid plug that blocks the airflow. The acoustic array detection and calculation module 13 monitors in real time that the sound pressure level drops rapidly from the initial 85 dB. The control and material supply center 21 dynamically adjusts the injection pressure according to the rising curve of the sealing degree η to prevent material splashing. Next, the repair robotic arm 12 switches the targeted electromagnetic induction heating gimbal 123 above the repair area and applies a high-frequency alternating magnetic field for about 60 seconds. During this time, the cross-linking endpoint is confirmed by resistivity monitoring, which promotes the complete cross-linking and curing of the resin matrix. After the repair was completed, the acoustic array detection and calculation module 13 confirmed that the leakage noise had disappeared, and the system successfully completed the live in-situ emergency repair operation under full load conditions without stopping the machine.

[0062] This application case demonstrates that the system of this invention can achieve millimeter-level precise positioning, in-situ pressurized repair, and closed-loop effect verification under the actual operating conditions of a subsea high-pressure gas storage facility. It completely solves the various pain points in the background technology and has significant economic benefits and engineering application value.

[0063] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the elements or objects preceding “comprising” or “including” encompass the elements or objects listed following “comprising” or “including” and their equivalents, and do not exclude other elements or objects. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0064] The above description is merely an optional embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A system for inspecting and repairing welded seams of steel linings in a subsea gas storage facility, characterized in that, include: Inspection and repair robot (1) and control components (2). The inspection and repair robot (1) resides on the inner wall of the steel lining of the subsea gas storage tank. It includes a magnetic wheel chassis (11) and a repair robotic arm (12) and an acoustic array detection and calculation module (13) set on the magnetic wheel chassis (11). The end of the repair robotic arm (12) is integrated with a high-pressure injection gun (121) for leak repair material. The acoustic array detection and calculation module (13) is used to capture broadband sound waves and turbulent high-frequency noise generated by high-pressure gas leakage for sound source localization and monitoring. The acoustic array detection and calculation module (13) includes a uniform circular array or spherical array composed of multiple high-frequency broadband ultrasonic microphones. The control component (2) includes a control and material supply center (21) deployed outside the subsea gas storage, an intelligent servo reel transceiver mechanism (22), and a composite umbilical cable (23) connecting the control and material supply center (21) and the inspection and repair robot (1). The composite umbilical cable (23) is threaded through the steel lining of the subsea gas storage and wound around the intelligent servo reel transceiver mechanism (22). The intelligent servo reel transceiver mechanism (22) is used to release or tighten the composite umbilical cable (23) according to the speed and displacement signals fed back by the inspection and repair robot (1). The composite umbilical cable (23) integrates a high-voltage transmission line core (231), a communication optical fiber (232), and a material delivery hose (233). The control and material supply center (21) is electrically connected to the inspection and repair robot (1) through the high-voltage transmission line core (231), communicates with the acoustic array detection and calculation module (13) through the communication optical fiber (232), and is connected to the high-pressure injection gun (121) for the leak repair material through the material delivery hose (233). The control and material supply center (21) stores a leak repair material, which is a pressure-sensitive shear thickening-liquid metal composite material, including a shear thickening fluid, gallium-based liquid metal microdroplets doped and distributed in the shear thickening fluid, and magnetic nanoparticles and thermosetting resin microcapsules. The shear-thickening fluid is formed by uniformly dispersing nano-silica particles in polyethylene glycol; the gallium-based liquid metal microdroplets are gallium indium tin liquid metal; the magnetic nanoparticles are Fe3O4 magnetic nanoparticles; and the thermosetting resin microcapsules are microcapsules containing epoxy resin. The end of the repair robotic arm (12) is also provided with a high-pressure micro water jet cleaning nozzle (122) and a targeted electromagnetic induction heating gimbal (123), and the targeted electromagnetic induction heating gimbal (123) is integrated with an infrared temperature sensor and electrode contact points. The targeted electromagnetic induction heating gimbal (123) is used to apply a controllable high-frequency alternating magnetic field above the repair area after the repair material is injected. The Fe3O4 magnetic nanoparticles dispersed inside the repair material are induced to generate a magnetic hysteresis effect through electromagnetic induction. The infrared temperature sensor is used to monitor the surface temperature of the repair area, and the electrode contact point is used to measure the resistivity change of the repair material.

2. The inspection and repair system for steel lining welds in a subsea gas storage facility according to claim 1, characterized in that, The material conveying hose (233) is a PTFE high-pressure material conveying hose reinforced with Kevlar fiber braiding, and the composite umbilical cable (23) is covered with a polyurethane sheath.

3. The inspection and repair system for steel lining welds in a subsea gas storage facility according to claim 1, characterized in that, The magnetic chuck chassis (11) is a variable curvature magnetic chuck chassis using a Halbach array permanent magnet wheel system.

4. The inspection and repair system for steel lining welds in a subsea gas storage facility according to claim 1, characterized in that, The acoustic array detection and calculation module (13) is located at the front end of the magnetic wheel system chassis (11).

5. A repair method based on the inspection and repair system for the steel lining welds of a subsea gas storage facility according to any one of claims 1 to 4, characterized in that, include: Step 1: The inspection and repair robot (1) patrols along the weld seam on the inner wall of the steel lining of the subsea gas storage facility. The control and material supply center (21) supplies the leak repair material and power through the composite umbilical cable (23) and retracts and extends the composite umbilical cable (23) through the intelligent servo reel transceiver mechanism (22). Step 2: Use the acoustic array detection and calculation module (13) to continuously monitor and locate the leak point, and instruct the inspection and repair robot (1) to move directly above the leak point; Step 3: Use the high-pressure injection gun (121) to fill the crack at the leak point with the leak-sealing material, and use the acoustic array detection and calculation module (13) to monitor it in real time until the broadband sound waves and turbulent high-frequency noise generated by the high-pressure gas leak disappear.

6. The repair method according to claim 5, characterized in that, The acoustic array detection and calculation module (13) includes a uniform circular array or spherical array composed of multiple high-frequency broadband ultrasonic microphones, and step two includes: Establish a spatial coordinate and signal propagation model; Calculate the time difference of arrival of the sound wave from the leak point to any two of the high-frequency broadband ultrasonic microphones; Based on SRP-PHAT spatial spectrum estimation and extreme value tracking, millimeter-level precise location of cracks at the leakage point is achieved.

7. The repair method according to claim 5, characterized in that, The end of the repair robotic arm (12) is equipped with a high-pressure micro-water jet cleaning nozzle (122) and a targeted electromagnetic induction heating gimbal (123). The targeted electromagnetic induction heating gimbal (123) integrates an infrared temperature sensor and electrode contact points. Step three includes: The area where the crack is located is cleaned using the high-pressure micro water jet cleaning nozzle (122); The repair material is injected into the crack at the leak point using a high-pressure injection gun (121) to form a repair area; An alternating magnetic field is applied using the targeted electromagnetic induction heating gimbal (123), the surface temperature of the repair area is monitored using the infrared temperature sensor, and the resistivity change of the repair material is measured using the electrode contact point. The acoustic array detection and calculation module (13) is used to monitor the repair area to confirm that the broadband sound waves and turbulent high-frequency noise generated by the high-pressure gas leak have disappeared.

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