Synchronous construction method for pipeline under-pressure welding and heat tracing line leakproof laying

Abstract

The invention relates to the technical field of pipeline repair and maintenance, and aims to solve the technical problems of protection window period and cross operation damage risk existing in traditional step-by-step construction. According to the technical scheme, joint inspection is carried out in a limited operation window, and a public operation area is planned; heat tracing wires are fixed on two sides of the area firstly, so that the part spanning the area forms a suspended section; a heat insulation barrier and a temperature monitoring point are arranged on the edge of the area, and controlled welding is conducted with a safety threshold value as the standard; and after welding, the suspended section heat tracing wire is laid and fixed to form a complete loop. According to the method, the problems of the window protection period and the cross damage risk existing in traditional step-by-step construction are solved, pipeline repair and heat tracing system reconstruction are safely, efficiently and synchronously completed in a single parking window, and the reliability and economical efficiency of integrity recovery of the system are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of pipeline repair and maintenance technology. More specifically, this invention relates to a method for simultaneously performing pressurized pipeline welding and leak-proof laying of heat tracing cables. Background Technology

[0002] In continuous production systems in the petrochemical and energy industries, critical pipelines such as flare lines play a vital role in safety venting. These pipelines are typically equipped with electric heat tracing systems to prevent process media from condensing or freezing in winter or low-temperature environments, ensuring unobstructed flow and system safety. However, after long-term operation, these pipelines may encounter two types of problems simultaneously: first, defects in the pipeline itself due to corrosion or other reasons may require repair; second, the external heat tracing wires may need replacement due to aging or damage. These two maintenance needs often coexist and must be addressed to ensure system integrity.

[0003] Currently, the standard procedure for handling such problems in the industry is a step-by-step sequential construction. This typically involves two modes: the first is "weld first, then lay," which means stopping the pipeline, performing pressurized welding repairs on the defects, and then laying new heat tracing cables after the welded area has completely cooled. The second is "lay first, then weld," which means replacing the heat tracing cables first, and then performing pressurized welding on the pipeline where the heat tracing cables have already been laid.

[0004] However, these two traditional models reveal significant inherent flaws when applied to demanding scenarios such as plant-wide flare systems, where shutdown costs are extremely high and operational windows are extremely short: 1) Weld-then-layup model: There is a "protection window" between the completion of welding and the commissioning of the new heat tracing line. During this period, the weld and nearby pipelines are without heat tracing. If the ambient temperature is too low, there is a significant safety hazard of freezing of the medium in the new weld area, which contradicts the original purpose of maintenance. 2) Layup-then-weld model: Exposing the delicate electrical heat tracing line directly to the high-temperature arc, molten spatter, and intense heat radiation generated by pressurized welding can easily lead to burnout of the heat tracing line insulation, short circuits, or even fires. Repairing a pipeline defect can damage the entire heat tracing system, posing a very high risk. 3) Low efficiency and increased costs: Step-by-step construction means that at least two major preparation and finishing processes are required, and the overall shutdown time may be longer or multiple shutdowns may be arranged due to the mutual constraints between the two types of operations. This seriously conflicts with the urgent need to "solve all problems in one limited window of time".

[0005] Therefore, there is an urgent need in this field for an innovative construction method that can safely and efficiently achieve simultaneous pressurized pipeline welding and heat tracing wire replacement, thereby completely eliminating the "protection window period," avoiding the risks of cross-operations, maximizing the use of valuable system downtime windows, and restoring the mechanical integrity and thermal protection functionality of the pipeline in one go. No existing technology has yet provided a systematic solution to this contradiction. Summary of the Invention

[0006] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0007] Another objective of this invention is to provide a method for simultaneous construction of live pipeline welding and leak-proof laying of heat tracing lines. This method enables the safe, efficient, and high-quality simultaneous completion of live pipeline welding repair and heat tracing system reconstruction within a single limited shutdown window, fundamentally solving the comprehensive technical problems of high safety risks, long construction period, high cost, and insufficient system recovery reliability inherent in traditional step-by-step construction methods.

[0008] To achieve these objectives and other advantages according to the present invention, a method for simultaneous construction of live pipeline welding and leak-proof laying of heat tracing lines is provided, comprising: Includes the following steps: S1. Joint Inspection and Planning: During the same operation window of the pipeline, a joint inspection is carried out on the target pipeline section to simultaneously identify the defective parts on the outer wall of the pipeline that need to be welded and repaired, as well as the sections covered by the heat tracing line that need to be re-laid, and to plan a common operation area that includes all the defective parts. S2. Expose common work area: Remove all existing coverings that obstruct welding operations in the common work area to fully expose the pipe surface in the area; S3. Pre-laying of heat tracing wire in sections: On the pipes on both sides of the public work area, complete the formal laying and fixing of the new heat tracing wire; The part of the new heat tracing wire that crosses the entire public work area is temporarily maintained above the outer surface of the pipe and kept in a non-adherent state to form a suspended section. S4. Heat-affected zone isolation and monitoring: A temporary heat insulation barrier is installed on the outer wall of the edge pipe in the public work area; a temperature monitoring point is installed near the barrier on the new heat tracing line that has been fixed outside the public work area, and a safe temperature threshold based on the heat tracing line's temperature resistance characteristics is set. S5. Controlled welding operation: The defective parts in the public work area are sequentially welded under pressure; during the welding process, the temperature of the temperature monitoring point is monitored in real time. When the temperature reaches the safe temperature threshold, the welding is immediately interrupted and resumed after it drops below the safe temperature threshold until all defective parts are welded. S6. System Integration: After the welding operation is completed and the surface temperature of the pipeline in the common work area cools down to a safe operating temperature, the temporary heat insulation barrier is removed; then, the slack heat tracing wire of the suspended section is laid and fixed tightly along the contour of the pipeline surface, including all new welds, so that it is electrically connected with the heat tracing wires fixed on both sides to form a complete heat tracing circuit.

[0009] Preferably, in step S4: temperature monitoring points are set on the fixed new heat tracing line at at least two different locations outside the public work area and around the circumference of the pipeline to form a distributed temperature monitoring network; In step S5: the temperature data of each monitoring point in the distributed temperature monitoring network is collected and compared in real time; when the temperature of any monitoring point reaches the safe temperature threshold, welding is immediately interrupted; after welding is interrupted, the pipeline area corresponding to the location of the monitoring point with the lowest current temperature is selected as the work location for resuming welding.

[0010] Preferably, in step S3, the temporary support is achieved through a temporary support assembly; the temporary support assembly includes a base that can be temporarily fixed to the outer wall of the pipe, and a high-temperature resistant flexible traction wire extending from the base to the upper part of the common work area; the free end of the flexible traction wire is provided with a high-temperature resistant clamp for gently clamping the heat tracing wire; by adjusting the effective length of the flexible traction wire, the clamped heat tracing wire segment is maintained at a preset safe distance above the surface of the pipe in the common work area and kept in a relaxed state.

[0011] Preferably, the execution of the method relies on a digital collaborative management and control platform, and includes predictive operation optimization and real-time functional verification steps implemented by the platform, as follows: Before step S1, there is also step S0, as follows: S0. Modeling: Before the operation, a digital twin model for thermal process simulation is established in the digital collaborative management and control platform based on the pipeline parameters, three-dimensional defect data and environmental parameters of the public operation area. Following step S6, there are also steps S7 and S8, as detailed below: S7. Predictive Optimization: During the welding process in step S5, the platform collects welding process parameters and temperature monitoring data in real time; based on the digital twin model and real-time data, it dynamically simulates the future temperature rise trend of each monitoring point through its built-in heat conduction prediction algorithm; when the simulation predicts that any monitoring point will exceed the safe temperature threshold, the platform issues an early warning before reaching the actual threshold and generates optimization adjustment suggestions for the welding sequence or parameters. S8. Real-time verification: After step S6 is completed and before the system resumes operation, the platform control will power on and debug the newly formed complete heat tracing circuit, and simultaneously execute: (a) Acquire the infrared thermal image of the common working area and compare it with the expected heat distribution benchmark image generated based on the digital twin model and design parameters to evaluate the uniformity and integrity of the heat tracing coverage; (b) Acquire the real-time operating current and insulation resistance parameters of the heat tracing circuit and compare them with the pre-stored normal range. The platform determines that the synchronous construction is qualified if and only if both comparison results (a) and (b) meet the requirements.

[0012] Preferably, after step S3 is completed and before step S5 begins, a handheld or fixed 3D structured light scanner is used to scan the common working area and the suspended section; the 3D point cloud data obtained from the scan is automatically registered and compared with the digital twin model; the comparison generates and outputs two quantifiable verification reports: (c) Overhang Distance and Coverage Compliance Report: Based on the three-dimensional point cloud data, calculate the measured distance from each sampling point on the overhang section to the pipe surface; when the measured distance of all sampling points is not less than the preset minimum safety distance, and the overhang section completely covers the vertical projection area of ​​all defective parts in three-dimensional space, the report is passed; (d) Barrier Location Installation Compliance Report: Based on the three-dimensional point cloud data, identify the actual edge position of the temporary thermal insulation barrier and calculate its deviation from the design position specified in the digital twin model in the circumferential and axial directions of the pipeline; when the deviation values ​​in all directions do not exceed the preset allowable installation tolerance, the report is passed; The welding operation in step S5 can only proceed after both of the above verification reports show that they have passed.

[0013] Preferably, in step S6, the suspended section is formally laid and fixed as follows: a flexible thermally conductive gap-filling adhesive layer is first coated on the pipe surface containing all new welds; while laying the suspended section heat tracing wire, a flexible thin-film sensing strip parallel to the heat tracing wire is placed between the thermally conductive gap-filling adhesive layer and the suspended section heat tracing wire; the flexible thin-film sensing strip integrates a distributed temperature sensor and a micro-strain sensor array; the signal cable of the flexible thin-film sensing strip and the power cable of the heat tracing wire are led out together and connected to the data acquisition module of the digital collaborative management and control platform; The control platform is configured to continuously monitor the temperature distribution uniformity and strain distribution data of the interface area between the adhesive layer and the heat tracing wire during subsequent system operation, and establish a baseline for the health status of the heat tracing system in that area based on this; when the monitoring data deviates abnormally, the platform issues a maintenance warning for that specific area.

[0014] Preferably, in step S6, when the newly formed complete heat tracing circuit is electrically configured and operated, the following steps are performed: A1. Independent zone power supply configuration: The heat tracing line segment corresponding to the public working area is electrically configured as an independently adjustable branch driven by an independent power supply control module; A2. Setting up a multi-stage operation strategy: In the digital collaborative management and control platform, at least two operation stages are preset for the independently adjustable branch: (i) Weld solidification and temperature stabilization stage: During the preset initial period after welding is completed, a constant first target temperature higher than the conventional antifreeze temperature is set, and the branch is controlled to work continuously to reach this temperature; (ii) Long-term antifreeze operation stage: After the initial period ends, the target temperature is switched to the conventional antifreeze temperature, and the branch is switched to an intermittent working mode based on ambient temperature sensing. A3. Strategy Execution and Monitoring: The digital collaborative management and control platform automatically switches the operation phase according to preset time nodes and controls the independent power supply control module to execute the corresponding power supply strategy; at the same time, it continuously monitors the operating current and temperature feedback data of the branch to ensure that it operates according to the strategy.

[0015] Preferably, the digital collaborative management and control platform is further configured to perform data-driven health prediction of the heat tracing system during long-term system operation: the platform continuously records and analyzes the operating data of the independently controllable branch, including its historical power adjustment curve, the percentage of cumulative working time required to maintain the set temperature, and the temperature uniformity and strain data fed back by the flexible thin-film sensing strip; the platform has a built-in heat tracing system health prediction model, which uses the aforementioned operating data as input features; the model analyzes the changing trends of the features, quantitatively evaluates and outputs the current health index and expected remaining reliable life of the heat tracing system in the repair area; when the health index is lower than a preset threshold, or the expected remaining reliable life is shorter than a preset maintenance plan cycle, the platform generates a preventive maintenance warning in advance.

[0016] The present invention has at least the following beneficial effects: First, by conducting joint inspections and planning of pipeline defects and heat tracing line replacement needs within the same work window, the systematization of maintenance tasks and the definition of a one-time work scope have been achieved, solving the problems of repeated preparation and planning coordination difficulties caused by the separation of the two types of work in the traditional model.

[0017] Secondly, by completing the formal laying of the heat tracing wire on both sides of the welding area in advance, and temporarily isolating the part that crosses the welding area in a suspended manner, the heat tracing wire is "pre-positioned" before welding, which solves the risk of the protection gap period in the "weld first, lay later" mode, and avoids the risk of damage to the heat tracing wire directly exposed to the high temperature of welding in the "lay first, weld later" mode.

[0018] Third, by setting up heat insulation barriers at the boundary of the work area and monitoring the temperature of adjacent heat tracing lines, and using this data to control the start and stop of welding in real time, dynamic and quantitative management of the relationship between welding heat impact and the safety of heat tracing lines is achieved, solving the process conflict problem of coexisting high-temperature welding and the safety of precision electric heat tracing elements.

[0019] Fourth, by formally laying and integrating the pre-laid suspended section heat tracing wire after welding cooling, a seamless connection from "protective pre-installation" to "functional integration" was achieved, solving the technical problem of quickly forming a complete and reliable heat tracing circuit after synchronous construction and ensuring the immediate restoration of system function.

[0020] Fifth, it has achieved safe, efficient, and high-quality simultaneous completion of pipeline pressurized welding repair and heat tracing system reconstruction within a single limited parking window, fundamentally solving the comprehensive technical problems of high safety risks, long construction period, high cost, and insufficient system recovery reliability of traditional step-by-step construction methods.

[0021] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0023] This invention discloses a method for simultaneous construction of live pipeline welding and leak-proof laying of heat tracing cables, comprising the following steps: S1. Joint Inspection and Planning: During the same operation window of the pipeline, a joint inspection is carried out on the target pipeline section to simultaneously identify the defective parts on the outer wall of the pipeline that need to be welded and repaired, as well as the sections covered by the heat tracing line that need to be re-laid, and to plan a common operation area that includes all the defective parts. S2. Expose common work area: Remove all existing coverings that obstruct welding operations in the common work area to fully expose the pipe surface in the area; S3. Pre-laying of heat tracing wire in sections: On the pipes on both sides of the public work area, complete the formal laying and fixing of the new heat tracing wire; The part of the new heat tracing wire that crosses the entire public work area is temporarily maintained above the outer surface of the pipe and kept in a non-adherent state to form a suspended section. S4. Heat-affected zone isolation and monitoring: A temporary heat insulation barrier is installed on the outer wall of the edge pipe in the public work area; a temperature monitoring point is installed near the barrier on the new heat tracing line that has been fixed outside the public work area, and a safe temperature threshold based on the heat tracing line's temperature resistance characteristics is set. S5. Controlled welding operation: The defective parts in the public work area are sequentially welded under pressure; during the welding process, the temperature of the temperature monitoring point is monitored in real time. When the temperature reaches the safe temperature threshold, the welding is immediately interrupted and resumed after it drops below the safe temperature threshold until all defective parts are welded. S6. System Integration: After the welding operation is completed and the surface temperature of the pipeline in the common work area cools down to a safe operating temperature, the temporary heat insulation barrier is removed; then, the slack heat tracing wire of the suspended section is laid and fixed tightly along the contour of the pipeline surface, including all new welds, so that it is electrically connected with the heat tracing wires fixed on both sides to form a complete heat tracing circuit.

[0024] In the above technical solution, the first step in implementation is joint inspection and work planning. During a pre-determined shutdown window for the pipeline system, such as a continuous 8-hour shift, personnel are organized to inspect the target pipe section. The inspection can be conducted in steps: First, a visual inspection of the pipeline's appearance is performed, and an ultrasonic thickness gauge is used to conduct grid-like measurements on the outer wall of the pipeline, recording the location and extent of localized thinning areas where the wall thickness is significantly lower than the design value. Second, for areas suspected of having internal defects or corrosion, temporary inspection holes can be opened on the corresponding pipe section, or an industrial video endoscope can be inserted into the existing flange interface for observation. The internal defect features observed by the endoscope (such as pitting and cracks) are compared and correlated with the locations detected by the external ultrasonic thickness gauge, for example, by establishing a unified length coordinate along the pipeline axis for mapping, thereby simultaneously identifying the defect locations that need to be welded and repaired on the outer wall of the pipeline. Simultaneously, sections of the existing electric heat tracing cable that need replacement are inspected and marked; these sections typically exhibit insulation damage, cracking, or abnormal resistance. Based on the distribution of all defects requiring welding, a rectangular common working area should be planned. The length of this area along the axial direction of the pipe should cover all defect edges and extend outwards by at least 200 mm to facilitate operation. Along the circumference of the pipe, it should cover the entire fan-shaped area or the entire circumference that needs to be welded and repaired.

[0025] Next, clean the area and pre-lay the heat tracing cable. Use appropriate tools to remove any coverings from the pipe surfaces in the common work area. For example, rigid polyurethane foam insulation can be cut and removed using a handsaw or electric saw; asphalt-based corrosion protection can be softened by gently heating with a flame torch before scraping it off with a scraper. After cleaning, use an angle grinder with a grinding wheel to polish the pipe's metal surface until a metallic luster is revealed and the cleanliness and roughness required for welding are achieved. Then, formally lay the new constant-power electric heat tracing cable on the intact pipes on both sides of the common work area. The insulation material can be modified polyolefin or fluoroplastic. Securely bind the heat tracing cable to the pipe using stainless steel cable ties spaced no more than 300 mm apart. For heat tracing cable sections that must cross the common work area, use a temporary support scheme to suspend them. The support assembly can include a base, which can be an adsorption block with a strong magnet (suitable for carbon steel pipes) or an adjustable stainless steel chain clamp (suitable for non-magnetic pipes such as stainless steel). A high-temperature resistant flexible component, such as a soft rope braided from stainless steel wire or a fiberglass rope coated with silicone, is connected to the base. Its short-term temperature resistance should not be lower than 300 °C. A high-temperature resistant clamp, such as one made of ceramic or high-temperature engineering plastic, is attached to the free end of this flexible component. The heat tracing wire is gently clamped with this clamp. By adjusting the length of the flexible component, the clamped section of heat tracing wire is allowed to slackly suspend above the pipe surface, maintaining a preset safety distance of 80 mm to 150 mm to ensure it does not contact the pipe surface during welding, thus forming a suspended section.

[0026] Subsequently, thermal insulation is installed and controlled welding is performed. At the edge of the common work area, a temporary thermal barrier is installed tightly against the outer wall of the pipe. This can be one or two layers of ceramic fiber blanket, with a total thickness of not less than 25 mm, ensuring complete circumferential coverage of the pipe. On the outside of the thermal barrier, on the fixedly laid heat tracing cable, at least two temperature monitoring points are selected. For example, a K-type armored thermocouple is installed at the top and side of the pipe cross-section. The measuring end of the thermocouple must be in good contact with the outer surface of the heat tracing cable and secured with high-temperature tape. The thermocouples are connected to a portable temperature recorder with multi-point monitoring and alarm functions. The safe temperature threshold is set based on the short-term maximum withstand temperature of the insulation material specified in the product manual of the selected heat tracing cable. For example, if the manual indicates that the heat tracing cable can withstand a short-term high temperature of 205 ℃, the safe temperature threshold can be conservatively set to 40%-50% of that value, i.e., between 82 ℃ and 102 ℃, specifically 90 ℃. Begin sequentially welding defects within the common work area under pressure, using manual shielded metal arc welding (SMAW). During welding, monitoring personnel observe the temperature readings at each monitoring point in real time. When the temperature at any monitoring point reaches the preset 90°C threshold, immediately instruct the welder to stop welding. During the pause, a portable blower can be used to cool the area with the higher temperature. Welding operations can resume only after all monitoring point temperatures have dropped to at least 15°C below the threshold (e.g., below 75°C). When resuming welding, prioritize welding the defects furthest from the currently highest-temperature monitoring point to even out heat input. Repeat this cycle until all defects in the area have been welded.

[0027] After welding, system integration is performed. Allow the pipe surface temperature in the common work area to cool naturally to below 50°C, which can be verified at multiple points using a handheld infrared thermometer. Then carefully remove the ceramic fiber blanket insulation barrier. Apply a layer of flexible silicone thermally conductive sealant to the pipe surface containing the new weld, spreading it evenly with a scraper to form a continuous thin layer approximately 1-2 mm thick. Loosen the previously suspended heat tracing wire segment, allowing it to smoothly adhere to the sealant-coated pipe surface. Secure this heat tracing wire segment tightly using standardized high-temperature resistant stainless steel clips or new stainless steel cable ties at intervals not exceeding 250 mm. Finally, perform electrical connections: using manufacturer-supplied dedicated connectors (such as crimp sleeves) or waterproof junction boxes conforming to industry standards (such as the relevant requirements in GB 50217 Power Engineering Cable Design Standard), reliably connect the conductors at both ends of this heat tracing wire segment to the already fixed heat tracing wire conductors on both sides, ensuring proper insulation, sealing, and waterproofing to form a complete electrically connected heat tracing circuit. After completion, use a megohmmeter to measure the circuit insulation resistance. The value should not be lower than 20 MΩ. Then, conduct a power-on test run to observe whether the heating is uniform and verify the construction quality.

[0028] This method achieves systematic integration of pipeline repair and heat tracing replacement tasks within the same operational window, and delineates a common operational area, thus avoiding the repetitive planning and coordination difficulties of the traditional step-by-step approach. By first formally laying the heat tracing lines on both sides of the area, and then temporarily isolating the sections crossing the area by suspending them, it ensures that the main body of the heat tracing lines is kept away from the high-temperature zone during welding, and also keeps them in a "near-position" state. This fundamentally eliminates the risk of a window period without heat protection during weld cooling in the traditional "weld first, lay later" approach, and also eliminates the hidden danger of the heat tracing lines being directly damaged by the high temperature of welding in the "lay first, weld later" approach.

[0029] By setting up thermal insulation barriers and installing temperature monitoring points and safety thresholds on nearby fixed heat tracing lines, proactive isolation and quantitative monitoring of the thermal impact of welding are achieved. Real-time temperature data controls the start and stop of welding operations, dynamically managing welding heat input and ensuring that the temperature of critical parts of the heat tracing line remains below safe limits. This resolves the core technological conflict between the high-temperature welding process and the safe coexistence of precision electric heat tracing elements.

[0030] After welding and cooling, the suspended section of the heat tracing cable is laid and fixed, and electrically integrated with the lines on both sides, achieving a seamless transition from construction to functional status. This method is sequential and highly operable, enabling all key operations of pipeline repair and heat tracing system reconstruction to be completed sequentially within a single, limited downtime window. This effectively shortens the overall construction period, reduces safety and quality risks caused by multiple operations or overlapping construction, and facilitates a one-time, reliable restoration of the pipeline's mechanical integrity and active thermal protection function.

[0031] In another technical solution, in step S4: temperature monitoring points are set on the fixed new heat tracing line at at least two different locations outside the public work area and around the circumference of the pipeline to form a distributed temperature monitoring network; In step S5: the temperature data of each monitoring point in the distributed temperature monitoring network is collected and compared in real time; when the temperature of any monitoring point reaches the safe temperature threshold, welding is immediately interrupted; after welding is interrupted, the pipeline area corresponding to the location of the monitoring point with the lowest current temperature is selected as the work location for resuming welding.

[0032] In the above technical solution, the setup of a distributed temperature monitoring network is crucial when setting up heat-affected zone isolation and monitoring in step S4. Temperature sensors can be installed at least four representative circumferential locations around the pipe outside the public work area and on the formally laid heat tracing line. For example, sensors can be placed at the top (0° or 12 o'clock), bottom (180° or 6 o'clock), and sides (e.g., 90° and 270°) of the pipe cross-section. Sensitive T-type or K-type armored thermocouples can be used. Their measuring ends must be tightly fitted to the outer sheath of the heat tracing line and secured with high-temperature resistant metal cable ties or special clips to ensure good heat conduction. The leads of these thermocouples are connected to a multi-channel (at least four channels) portable data acquisition instrument, which has real-time display, data recording, and independent channel alarm functions. The safe temperature threshold is set in accordance with the principle in claim 1, for example, uniformly set to 90°C. This forms a distributed network for real-time monitoring of the circumferential heat distribution of the pipe.

[0033] When performing controlled welding operations in step S5, intelligent decision-making is required using the aforementioned distributed network. During welding, the data acquisition instrument continuously records and displays the real-time temperature of all monitoring points on the same screen. Operators or monitoring systems must simultaneously monitor the readings of each channel. When the temperature of any monitoring point in the network reaches the preset safety threshold of 90℃, the system should immediately trigger an audible and visual alarm and instruct the welder to immediately stop the current welding operation and interrupt the heat input. After welding is interrupted, the system or operator needs to check and compare the current stable temperature readings of each monitoring point. The decision logic for resuming welding is: prioritize the circumferential area of ​​the pipe corresponding to the monitoring point with the lowest current temperature reading for the next welding operation. For example, if the temperature of the top monitoring point is 90℃ (reaching the threshold first), the side point is 85℃, and the bottom point is 78℃ when the interruption occurs, then priority should be given to finding and welding defects (if any) in the bottom area of ​​the pipe (corresponding to the monitoring point with the lowest temperature of 78℃). If there are no defects in this area, then the area corresponding to the next lowest temperature point should be selected. This strategy aims to direct new heat input to the area with the lowest current temperature and least heat accumulation, thereby more evenly controlling the heat load of the heating wires surrounding the entire common work area and avoiding localized overheating. This comparison and decision-making process can be repeated after each welding interruption.

[0034] To ensure the effective implementation of this strategy, the following operational details are added: Before welding, the circumferential area of ​​the pipe corresponding to each temperature monitoring point (such as the top area, bottom area, etc.) should be clearly marked on the pipe surface or the outside of the insulation layer using a heat-resistant marker pen to facilitate quick positioning by the welder. The data acquisition instrument can be set to automatically record the time and value of each channel reaching its peak temperature, providing a basis for subsequent analysis. By implementing the above-mentioned distributed monitoring and welding recovery strategy based on the lowest temperature point, the heat impact of welding can be managed more precisely, the heat input distribution can be optimized spatially, the safety margin of the heat tracing line during synchronous construction can be further improved, and it may help to shorten the waiting time for cooling due to local overheating. The instruments and operations involved in the entire data acquisition, display, alarm, and manual decision-making (or simple logical judgment) process are all conventional technical means in temperature monitoring and process control in this field.

[0035] The beneficial effects of this technical solution are that by establishing a distributed temperature monitoring network and comparing the data in real time, a more comprehensive spatial monitoring of the thermal impact of welding is achieved. At the same time, based on the decision logic of "prioritizing the area corresponding to the monitoring point with the lowest current temperature to resume welding", heat input can be actively guided and heat accumulation in the circumference of the pipeline can be balanced, thereby providing more uniform and reliable protection for the adjacent heat tracing lines as a whole. This not only enhances the safety margin of the entire construction process, but may also improve welding efficiency by optimizing the operation sequence.

[0036] In another technical solution, in step S3, the temporary support is achieved through a temporary support assembly; the temporary support assembly includes a base that can be temporarily fixed to the outer wall of the pipe, and a high-temperature resistant flexible traction wire extending from the base to the upper part of the common work area; the free end of the flexible traction wire is provided with a high-temperature resistant clamp for gently clamping the heat tracing wire; by adjusting the effective length of the flexible traction wire, the clamped heat tracing wire segment is maintained at a preset safe distance above the surface of the pipe in the common work area and kept in a relaxed state.

[0037] In the above technical solution, the base can take two common forms to adapt to different pipe materials: for magnetic pipes such as carbon steel, neodymium iron boron strong magnets can be used as adsorption bases, and their bottom surfaces are usually equipped with anti-slip rubber pads to increase friction; for stainless steel, non-ferrous metal, or non-metallic pipes, slit-in stainless steel clamps with bolt-fastening structures can be used as mechanically fixed bases. During installation, the bases need to be fixed to the cleaned pipe surface outside the public work area, usually symmetrically arranged at both ends of the welding area, about 100mm to 200mm from the edge of the work area.

[0038] The flexible traction conductor can be made of stainless steel braided rope with a diameter of 1mm to 2mm, or a metal core rope wrapped with ceramic fibers, with a continuous operating temperature not lower than 400℃. One end of the conductor is connected to the base via a high-temperature resistant metal connecting ring (e.g., a stainless steel quick-release buckle). The free end of the conductor is equipped with a high-temperature resistant clamp, which can be made of integral high-temperature resistant ceramic (such as alumina ceramic) or injection molded from high-temperature engineering plastic (such as polyetheretherketone, PEEK). The clamp can be a spring-loaded clamping arm or a simple C-type buckle with a locking screw. Before clamping the heat tracing wire, a small, thin, high-temperature resistant silicone pad (approximately 1mm thick) can be attached to the inner surface of the clamp where it contacts the heat tracing wire to prevent damage to the insulation layer of the heat tracing wire.

[0039] The specific working process is as follows: First, attach or secure the two bases to the predetermined positions on the pipes on both sides of the common work area. Then, connect one end of the flexible traction wire to the base. Next, gently lift the heat tracing line segment crossing the common work area and clamp it in an appropriate position (usually near the inner edge of the work area) using a high-temperature resistant clamp. By adjusting the effective length of the traction wire (for example, if the wire is stainless steel wire rope, a self-locking adjusting buckle or spiral buckle can be used for fine-tuning), the clamped heat tracing line segment is raised above the pipe surface, maintaining a preset, uniform safety distance. This safety distance should be set according to the estimated welding heat input, usually selecting a specific value within the range of 80mm to 150mm, such as 100mm. During adjustment, ensure that the entire suspended heat tracing line is in a relaxed, drooping state, not taut, and has no contact with the pipe surface. Throughout the welding operation, this temporary support assembly must remain stable, and its material must be able to withstand the high-temperature radiation generated by adjacent welding and occasional sparks. After welding is completed, the clamps are loosened, and the connection between the wire and the base is severed, allowing for easy removal of the entire temporary support assembly without damaging the fixed heat tracing wire or pipe. This support assembly provides reliable, adjustable, and easily removable physical isolation for the heat tracing wire during welding, and is a key guarantee for achieving simultaneous construction.

[0040] The specific implementation of the temporary support assembly provides a clear and operable technical means for the aforementioned "temporarily maintaining the suspension of the heat tracing cable." By providing two base options (strong magnet blocks or half-clamps) compatible with both magnetic and non-magnetic pipes, the assembly's stable fixation under different field conditions is ensured. The use of high-temperature resistant flexible traction wires (such as stainless steel wire rope or ceramic fiber rope) with adjustable connectors allows the safe distance of the suspended section (e.g., 100mm) to be precisely set and maintained according to the welding heat input. Dedicated high-temperature resistant clamps (made of ceramic or PEEK) with protective rubber pads provide gentle and reliable clamping of the heat tracing cable, preventing damage. The assembly has a simple overall structure, is easy to install and disassemble, and provides stable and adjustable support for the heat tracing cable during welding, effectively isolating it from the high-temperature work area, thus providing the necessary mechanical support and thermal isolation conditions for the smooth execution of synchronous construction methods.

[0041] In another technical solution, the execution of the method relies on a digital collaborative management and control platform, and includes predictive operation optimization and real-time functional verification steps implemented by the platform, as follows: Before step S1, there is also step S0, as follows: S0. Modeling: Before the operation, a digital twin model for thermal process simulation is established in the digital collaborative management and control platform based on the pipeline parameters, three-dimensional defect data and environmental parameters of the public operation area. Following step S6, there are also steps S7 and S8, as detailed below: S7. Predictive Optimization: During the welding process in step S5, the platform collects welding process parameters and temperature monitoring data in real time; based on the digital twin model and real-time data, it dynamically simulates the future temperature rise trend of each monitoring point through its built-in heat conduction prediction algorithm; when the simulation predicts that any monitoring point will exceed the safe temperature threshold, the platform issues an early warning before reaching the actual threshold and generates optimization adjustment suggestions for the welding sequence or parameters. S8. Real-time verification: After step S6 is completed and before the system resumes operation, the platform control will power on and debug the newly formed complete heat tracing circuit, and simultaneously execute: (a) Acquire the infrared thermal image of the common working area and compare it with the expected heat distribution benchmark image generated based on the digital twin model and design parameters to evaluate the uniformity and integrity of the heat tracing coverage; (b) Acquire the real-time operating current and insulation resistance parameters of the heat tracing circuit and compare them with the pre-stored normal range. The platform determines that the synchronous construction is qualified if and only if both comparison results (a) and (b) meet the requirements.

[0042] In the above technical solution, the execution of the method relies on a digital collaborative management and control platform. This platform can be an industrial computer deployed within an explosion-proof enclosure on-site, or a combination of a remote server and on-site terminals connected via a network. Its core lies in achieving digital management and control of the construction process through three steps: modeling, prediction, and verification. Specifically: The specific implementation of step S0 (modeling) is as follows: Before starting the work, initiate the modeling process in the platform software. First, manually input or import the basic pipe parameters for the common work area from the database, including outer diameter (e.g., 219.1 mm), wall thickness (e.g., 8.2 mm), material (e.g., Q345R), and corresponding thermophysical properties (e.g., a data table showing thermal conductivity as a function of temperature). Second, import the 3D point cloud data of the defect area obtained through a 3D laser scanner. The platform software (which can integrate functional modules of open-source point cloud processing libraries such as Point Cloud Library (PCL)) guides the user in a semi-automated model reconstruction: the user first generates a regular cylindrical CAD model based on the pipe parameters as a reference; then, the software spatially registers the defect point cloud with this cylindrical surface; next, the user uses the "defect extraction" tool provided by the software to interactively select each defect area on the point cloud. The software automatically calculates the maximum depression depth and planar range of the point cloud within that area relative to the reference cylindrical surface, and simplifies each defect into a regular pit (e.g., cylindrical or spherical) feature with a specific depth, diameter, and center position. These features are parametrically "sculpted" onto the baseline CAD model, generating a 3D solid model of the pipeline that includes the defect geometry. Finally, the software calls the preprocessing module of its integrated open-source finite element analysis solver (such as CalculiX or CodeAster) to automatically mesh the solid model, generating tetrahedral or hexahedral meshes suitable for heat conduction analysis. Environmental parameters (such as ambient temperature and wind speed estimates) are used as boundary condition inputs. The model generated in this process is a digital twin model used for thermal process simulation.

[0043] The specific implementation of step S7 (predictive optimization) is as follows: This step relies on a specific heat conduction prediction algorithm. The core principle of this algorithm is to simplify the heat input from the welding arc to the pipe as a point heat source or a Gaussian surface heat source moving along the weld seam on the pipe surface. The algorithm utilizes the linear system characteristics of heat conduction in the pipe and is pre-calibrated through experiments or simulations.

[0044] As an example of an implementable heat conduction prediction algorithm, it is based on the "linear superposition principle" and a "pre-stored temperature response library," and the specific steps are as follows: (1) Precalibration and response library establishment Before construction, calibration tests are conducted on the test pipe section or through finite element simulation, taking into account the pipe material, wall thickness, and typical welding process (such as manual arc welding) of the public work area. The calibration method is as follows: thermocouples are placed at a specific distance d from the simulated heat source (the value of d is equivalent to the measured distance from the temperature monitoring point to the welding area in step S4), and the temperature rise at that point versus time under a unit welding heat input Q (e.g., the heat input for welding for 1 second under constant current and voltage) is recorded, i.e., the "unit step temperature rise response curve" Rd(t). A set of response curves is established for different circumferential directions (top, side, bottom) and different distances d of the pipe, and stored in the platform's "temperature response library".

[0045] (2) Real-time prediction calculation During the actual welding process in step S5, the platform performs the following calculations at a 1-second interval: 1) Quantification of heat input: Real-time acquisition of welding current I and voltage U, and calculation of instantaneous heat input power P(t)=η*I(t)*U(t), where η is the welding thermal efficiency coefficient (pre-set according to the process, such as 0.7).

[0046] 2) Future heat source path prediction: Based on the current moving speed v and direction of the welding torch, predict its future path T. p The movement trajectory within a time period (e.g., the next 30 seconds) is discretized into a series of location points.

[0047] 3) Temperature prediction overlay: For each temperature monitoring point j, the predicted temperature T at future time T is... jp (T) is calculated as follows: T jp (T)=T jc +Σ[P(t i )*Δt*R dj (Tt i )]; where T jc It is the current measured temperature at monitoring point j; Σ is the summation of all discrete welding position points i from the current time to the future time T; P(t i ) is time t i The heat input power; Δt is the time step; R dj It is a unit step temperature rise response curve function selected from the response library that matches the orientation and distance of the monitoring point; (Tt) i () is the time difference.

[0048] The calculation essentially involves superimposing the planned heat inputs from the future onto the current temperature state, according to their timing and location.

[0049] (3) Early warning and suggestion generation The platform calculates the predicted temperature sequence for all monitoring points in real time over a period of time (e.g., the next 30 seconds). When the prediction indicates that the temperature at any monitoring point will exceed its safety threshold within the next N seconds (e.g., 15 seconds), the platform issues an early warning. Simultaneously, the platform can perform a simple "what-if analysis": if the future welding segment that contributes the most to a certain over-temperature monitoring point is temporarily removed during the simulation, will the predicted temperature drop? If so, a suggestion is generated: "It is recommended to adjust the welding sequence and postpone welding at position XX."

[0050] The above algorithm only uses pre-calibrated linear response curves and real-time thermal input for convolution calculation, without the need to solve complex differential equations online. It has a low computational load and can run in real time on industrial control computers. It is a specific and feasible technical means to achieve predictive optimization.

[0051] The specific operation of step S7 is as follows: Before welding begins, a short trial weld is performed (or on a test piece made of the same pipe material), while simultaneously recording the welding current I, voltage U, speed v, and temperature response T(t) at a specific distance from the heat source (e.g., a position similar to the monitoring point in step S4). Based on this data, the algorithm uses system identification methods (such as fitting analytical solutions to the heat conduction differential equation, or a simple step response analysis method) to estimate the transfer function or temperature rise response curve per unit heat input from the welding heat input power P (P=ηIU, where η is the efficiency coefficient, which can be taken as an empirical value such as 0.7) to the temperature at each monitoring point.

[0052] During the actual welding process, the platform collects welding current, voltage, and speed in real time and calculates transient heat input power. The prediction algorithm's workflow is as follows: 1) Real-time data input: Welding parameters and temperatures at each monitoring point are collected once per second. 2) Future heat input prediction: Based on the current welding speed and path, the trajectory and power of the heat source on the pipe surface are estimated within the next 30-60 seconds. 3) Temperature prediction calculation: Using a pre-calibrated transfer function or response curve, with the current temperatures at each monitoring point as initial conditions, the predicted temperature rise generated by the planned future heat input is superimposed to dynamically calculate the predicted temperature sequence of each monitoring point within a future period (e.g., the next 30 seconds). This calculation uses the convolution or superposition principle and can be completed in real time on an industrial control computer. 4) Warning and suggestion generation: When the prediction calculation shows that the predicted temperature at any monitoring point will exceed the safety threshold (e.g., 90℃) within the next N seconds (e.g., 15 seconds), the platform triggers a warning. Optimization suggestions are generated based on prediction results. For example, "Monitoring point A is predicted to overheat in 25 seconds, it is recommended to suspend welding in its corresponding location" or "Monitoring point B's temperature is predicted to be safe, and work can continue in its corresponding area first." Welders adjust their operations accordingly.

[0053] The specific implementation of step S8 (instant verification) is as follows: After step S6 is completed, the platform controls the heat tracing circuit to be energized. The platform sends a closing command to the intelligent distribution cabinet via a communication interface (such as Profinet or Modbus TCP). After the power-on is stable (e.g., 5 minutes), the platform synchronously performs verification: (a) Infrared Thermal Imaging Comparison: The platform controls a pre-calibrated and fixed-position infrared thermal imager to capture thermal images of the public work area. The software first performs image registration: automatically identifying the contour features of pipes and welds in the thermal image and aligning them with the corresponding two-dimensional projection images from the digital twin model (using feature point matching algorithms such as SIFT or ORB). After registration, the software extracts the temperature values ​​of a series of sampling points along the laying path of the heat tracing cable in the thermal image. Simultaneously, it generates a baseline map of the expected heat distribution: the software calls the digital twin model to solve the three-dimensional temperature field of the pipe when the heat tracing cable is heating steadily under the same environmental parameters, and projects it onto the viewpoint aligned with the infrared image to generate a theoretical temperature distribution map. Finally, a consistency comparison is performed: the root mean square error (RMSE) and correlation coefficient of the measured temperature sequence and the theoretical temperature sequence at the same sampling point locations are calculated. When the RMSE is less than a set value (e.g., 3℃) and the correlation coefficient is greater than 0.85, it is considered to have passed.

[0054] (b) Electrical Parameter Comparison: The platform reads the circuit operating current through the connected smart meter and the insulation resistance value through the insulation resistance monitoring module. The software compares the current value with the theoretical range calculated according to the heat tracing wire specifications and compares the insulation resistance value with the minimum allowable value specified in the standard (e.g., 20 MΩ).

[0055] The platform is configured to output a "verification qualified" conclusion and generate an electronic report containing all comparison data only when both comparison results (a) and (b) meet their respective preset qualification standards.

[0056] The beneficial effects of this technical solution lie in providing a precise digital benchmark for construction by constructing a digital twin model that integrates defect geometry. The disclosed prediction algorithm enables the platform to dynamically simulate and warn of future thermal risks based on real-time data and a pre-calibrated thermal response model, achieving a leap from passive monitoring to proactive prediction. Automated infrared and electrical joint verification provides objective and quantitative quality acceptance methods. The entire digital process significantly improves the controllability, safety, and traceability of results during synchronous construction.

[0057] In another technical solution, after step S3 is completed and before step S5 begins, a handheld or fixed 3D structured light scanner is used to scan the common working area and the suspended section; the 3D point cloud data obtained from the scan is automatically registered and compared with the digital twin model; the comparison generates and outputs two quantifiable verification reports: (c) Overhang Distance and Coverage Compliance Report: Based on the three-dimensional point cloud data, calculate the measured distance from each sampling point on the overhang section to the pipe surface; when the measured distance of all sampling points is not less than the preset minimum safety distance, and the overhang section completely covers the vertical projection area of ​​all defective parts in three-dimensional space, the report is passed; (d) Barrier Location Installation Compliance Report: Based on the three-dimensional point cloud data, identify the actual edge position of the temporary thermal insulation barrier and calculate its deviation from the design position specified in the digital twin model in the circumferential and axial directions of the pipeline; when the deviation values ​​in all directions do not exceed the preset allowable installation tolerance, the report is passed; The welding operation in step S5 can only proceed after both of the above verification reports show that they have passed.

[0058] In the above technical solution, based on the aforementioned steps, a step of performing a three-dimensional digital verification of the physical construction state is added before the welding operation begins. The specific implementation method is as follows: After completing step S3 (segmented pre-laying of the heat tracing cable) and before officially starting step S5 (controlled welding operation), a 3D scan and compliance verification must be performed. This step requires a 3D structured light scanner, which can be a handheld blue light or white light scanning device (with a single-frame accuracy of up to 0.05 mm) or a fixed multi-view scanning system. To ensure the accuracy and stability of subsequent data registration, at least four highly reflective or specifically geometrically shaped positioning targets can be affixed to the pipe surfaces on both sides of the common work area.

[0059] Operators use the scanner to perform multi-angle scans of the entire public work area (including all defective surfaces and surrounding pipes), the suspended section of the heat tracing cable (requiring a complete scan of its spatial morphology), and the edges of the temporary insulation barrier. The scan data is stitched together in real time in the instrument's software to generate a fused, high-density 3D point cloud model containing color information, and the data is exported in .ply format.

[0060] Subsequently, the on-site 3D point cloud data is imported into the digital collaborative management and control platform. The platform then calls its integrated 3D point cloud processing module to execute an automatic registration and comparison process: 1. Data Registration: The platform first automatically identifies the 3D coordinates of the preset target center in the point cloud and matches them with the predefined target design coordinates in the digital twin model, completing the initial coarse registration. Then, using the point cloud data of the unobstructed regular cylindrical surface area of ​​the pipeline (usually the pipeline surface outside the insulation barrier) and the cylindrical surface of the digital twin model as a reference, an iterative nearest-point algorithm is used for fine registration. The root mean square error between the registered point cloud and the model in the main body of the pipeline should be less than 2mm.

[0061] 2. Overhang Distance and Coverage Compliance Analysis (Generate Report c): Definition and Sampling: Here, "vertical projection" refers to the projection along the normal direction of the theoretical surface of the pipe. The software extracts the outer contour lines of all defect locations in the digital twin model. Simultaneously, a sampling point is extracted every 15mm along the centerline from the point cloud of the suspended section of the heating wire.

[0062] Distance Calculation and Coverage Judgment: For each point on the defect profile, the software performs the following geometric judgment: Calculates the shortest distance from that point along the normal direction of the pipe's outer surface to the point cloud of the suspended section's heating wire. If this distance is negative (indicating that the heating wire point cloud is located between the pipe surface and the point) or less than a small positive tolerance value (e.g., +3mm, used to tolerate point cloud noise), then the defect point is considered to be "covered". For sampling points in the suspended section, the shortest Euclidean distance to the theoretical pipe surface is calculated as the measured suspended distance.

[0063] Compliance Logic and Report Generation: The software presets a minimum safe distance value, such as 100mm. Compliance judgment must simultaneously meet two conditions: (a) the measured distance of all suspended segment sampling points is not less than 100mm; (b) all points on the defect outline are judged as "covered". Only when both (a) and (b) are met will the software generate a "Suspended Distance and Coverage Compliance Report" with a conclusion of "Pass", including the minimum measured suspended distance, the maximum measured suspended distance, and the pass rate of the coverage judgment (which should be 100%). Otherwise, the report will be "Fail", and a list will be provided indicating which sampling points have insufficient distance or which defect areas are not covered.

[0064] 3. Barrier installation compliance analysis (generate report d): Edge Enhancement and Recognition: To improve the robustness of edge recognition, a 1-2cm wide matte black heat-resistant tape is applied around the design boundary line when laying the temporary heat insulation barrier. This creates a sharp contrast in color or brightness information between the tape and the gray ceramic fiber blanket and metal pipes in the point cloud. The software first extracts the point set of the black tape area from the point cloud based on a color threshold segmentation algorithm (e.g., setting lower limits for brightness and saturation in the HSV color space).

[0065] Feature extraction and deviation calculation: The extracted tape dot set is projected onto the theoretical cylindrical surface of the pipe, and the upper and lower (axial) and left and right (circumferential) boundary lines are fitted using a random sampling consensus algorithm. These fitted actual boundary lines are compared with the predefined thermal insulation barrier design boundary lines in the digital twin model. The deviation calculation method is as follows: points are taken at equal intervals along the design boundary line, the vertical distance from each point to its corresponding actual boundary line (axial or circumferential) is calculated, and then the average and maximum values ​​of these distances are statistically analyzed.

[0066] Compliance Assessment and Report Generation: The software pre-sets allowable installation tolerances, such as an average axial deviation of no more than ±10 mm (maximum ±15 mm) and an average circumferential angular deviation of no more than ±5° (maximum ±8°). When both the calculated average and maximum deviations are within the above tolerance ranges, the software generates a "Barrier Location Installation Compliance Report" with a conclusion of "Pass" and lists the deviation values. Otherwise, the report is "Fail" and indicates the direction and amount of the deviation.

[0067] The platform is configured with mandatory logic: the "Allow Welding" indicator light on the platform interface will only illuminate and the welding equipment's enable signal will be unlocked (or an electronic license will be generated) when both verification reports (c) and (d) above show "Pass". If either report fails, the platform will maintain the welding locked state and guide the operator to view the highlighted non-conformities in the 3D visualization interface, make physical adjustments, and then rescan and verify until it passes.

[0068] It should be noted that the requirement in step S3 to "keep the suspended section in a relaxed state" is to avoid excessive thermal stress on the heat tracing wire due to tension under welding heat radiation, and to facilitate subsequent laying. The aforementioned verification requirement of "completely covering the defect projection" is to ensure that the suspended section provides sufficient shielding and a safe distance to all defect areas below during welding operations. These two requirements can be met simultaneously through a reasonable arrangement of temporary supports. Specifically, the "temporary method" is not limited to setting support points only at both ends of the common work area. For large-diameter pipes or when defects are distributed at the top of the pipe, one or more intermediate temporary support points can be added to the top or side of the pipe. By adjusting the length of the flexible traction wire at each support point, the entire heat tracing wire can form a multi-segment suspended curve that is approximately parallel to the outer contour of the pipe in a relaxed state, thereby ensuring that its vertical projection can cover all defect locations. Alternatively, a manually shaped metal flexible tube can be temporarily fitted over the outside of the suspended section of the heat tracing wire. The shape retention of the flexible tube helps to form the required suspended shape, and the flexible tube is removed after welding. Those skilled in the art can flexibly adopt one or more of the above methods to achieve coordination between "relaxation" and "full coverage" based on the pipe diameter, defect distribution and site conditions.

[0069] The beneficial effect of this technical solution lies in the introduction of a digital pre-inspection process based on high-precision 3D scanning, and the use of specific and robust algorithms to achieve automated compliance judgment. This transforms the key quality requirements for construction preparation (safe distance, coverage integrity, installation accuracy) into objective, quantitative, and tamper-proof data decisions. This fundamentally avoids the subjective errors and oversights of human visual inspection, ensuring that all preconditions before welding operations begin fully meet the design requirements, thus building a reliable technical safety barrier for subsequent high-risk operations.

[0070] In another technical solution, in step S6, the suspended section is formally laid and fixed as follows: a flexible thermally conductive gap-filling adhesive layer is first coated on the surface of the pipe containing all new welds; while laying the suspended section heat tracing wire, a flexible thin-film sensing strip parallel to the heat tracing wire is placed between the thermally conductive gap-filling adhesive layer and the suspended section heat tracing wire; the flexible thin-film sensing strip integrates a distributed temperature sensor and a micro-strain sensor array; the signal cable of the flexible thin-film sensing strip and the power cable of the heat tracing wire are led out together and connected to the data acquisition module of the digital collaborative management and control platform; The control platform is configured to continuously monitor the temperature distribution uniformity and strain distribution data of the interface area between the adhesive layer and the heat tracing wire during subsequent system operation, and establish a baseline for the health status of the heat tracing system in that area based on this; when the monitoring data deviates abnormally, the platform issues a maintenance warning for that specific area.

[0071] In the above technical solution, the specific operation of formally laying and fixing the suspended section of the heat tracing wire in step S6 is as follows: 1. Surface Preparation and Adhesive Coating: On the pipe surface, including all new welds and cleaned (to Sa2.5 grade), apply a layer of flexible, one-component, room-temperature curing silicone thermally conductive adhesive using a toothed scraper. The thermal conductivity of this adhesive layer should be no less than 1.2 W / (m·K), and the coating thickness should be controlled at 1.5 mm. The toothed scraper ensures uniform adhesive layer thickness.

[0072] 2. Specifications and Laying of Flexible Thin-Film Sensing Strip: After the adhesive layer has initially dried (rested for approximately 5 minutes to reach a thixotropic state), a flexible thin-film sensing strip is immediately laid. This sensing strip is a custom-designed flexible circuit with a three-layer structure: the upper layer is a 25-micrometer-thick polyimide protective film, the lower layer is a 50-micrometer-thick polyimide substrate, and the middle layer is an 18-micrometer-thick copper foil etched with circuit patterns. Two types of sensor arrays are integrated along the length of the sensing strip: Distributed temperature sensor array: A digital temperature sensor chip (such as TMP117) is integrated every 300 mm and connected in series using an I2C bus.

[0073] Micro-strain sensor array: A metal foil strain gauge (resistance value 350Ω, grid wire length 3mm) is integrated between adjacent temperature sensors to form a Wheatstone bridge half-bridge circuit.

[0074] A complete copper layer serves as electromagnetic shielding on the back of the circuit layer (closest to the pipe). The signal cable for the sensor strip is a shielded, flexible, flat cable. During installation, the sensor strip must be pre-cut to the appropriate width according to the pipe's curvature and laid flat on the adhesive layer, ensuring no wrinkles. Immediately use a roller with a silicone pad to roll the sensor strip axially along the pipe to remove air bubbles and ensure complete adhesion to the adhesive layer.

[0075] 3. Heat Tracing Cable Laying and Integration: Next, lay the suspended section of the heat tracing cable along the centerline of the sensing belt. Use high-temperature resistant clips (300 mm intervals) to secure the heat tracing cable and sensing belt together to the conduit. The power cord of the heat tracing cable and the signal cable of the sensing belt are threaded together through a metal flexible conduit for protection and connected to a nearby IP66-rated junction box. The data acquisition module inside the box includes: a DC-DC isolated power supply for the I2C bus, a 24-bit analog-to-digital converter for reading the strain gauge bridge, and a microprocessor with edge computing capabilities (such as an ARM Cortex-M series). This module connects to the digital collaborative management platform via an RS-485 bus or an industrial Ethernet interface.

[0076] The specific implementation of data processing, baseline establishment, and anomaly early warning is as follows: The digital collaborative management and control platform is configured to perform the following tasks: 1. Data Acquisition and Preprocessing: The platform acquires data from all sensors once per hour. A moving average filter (window size of 5 sampling points) is applied to the raw data to eliminate transient noise.

[0077] 2. Establishment of dynamic health baseline: Data collected by the platform during at least one full year after the heat tracing system is put into normal operation is regarded as learning period data and used to establish a dynamic baseline model.

[0078] Temperature baseline model: The platform is based on the ambient temperature (T) E Using data obtained from the factory's weather station as the independent variable and the readings of each temperature sensor as the dependent variable, linear regression analysis was employed to establish an independent regression model for each sensor. For any sensor labeled S... x The temperature sensor, model T x =a x ×T E +b x Among them, T x It is sensor S x The predicted temperature value, a x and b x These are coefficients specific to this sensor, obtained through fitting. The sensor's dynamic normal temperature range is T. x ±3σ x , where σx This represents the standard deviation of the residuals in the regression model of this sensor.

[0079] Strain baseline model: for any given G y The strain sensor's readings are primarily affected by local temperature. The platform uses the readings of two adjacent temperature sensors (T...) m ,T n The average value T L (T) L =(T m +T n () / 2) is the independent variable, and the strain reading ε is the value of the strain. y Using ε as the dependent variable, establish a quadratic polynomial regression model: y =p y ×T L 2 +q y ×T L +r y Among them, p y q y r y The fitting coefficients are given. The normal dynamic fluctuation range of this strain sensor is equal to the model predicted value ε. y ±3σ y , where σ y This represents the standard deviation of the model residuals.

[0080] Temperature difference baseline: for any pair of adjacent temperature sensors S j With S k Calculate its historical temperature difference ΔT {jk} (ΔT) {jk} =T j -T k The 30-day moving average μ{ΔT) jk} and moving standard deviation σ{ΔT jk}

[0081] 3. Real-time Monitoring and Anomaly Detection Algorithm: After the baseline is established, the platform enters real-time monitoring mode. Anomaly detection is based on the following specific rules; triggering any one of these rules is considered an anomaly: Rule 1 (Temperature Anomaly): Any temperature sensor S x The real-time readings, continuously for two acquisition cycles (2 hours), exceeded its value based on the current ambient temperature T. E Calculated dynamic normal range (T) x ±3σ x ).

[0082] Rule 2 (Temperature Difference Abnormality): Any pair of adjacent temperature sensors S j With S k The absolute value of the real-time temperature difference |ΔT {jk}|, exceeding 2.5×μ{ΔT} for three consecutive periods jk}, and simultaneously exceed 2×σ{ΔT jk}

[0083] Rule 3 (Strain Anomaly): Any strain sensor G y The real-time readings, after removing the predicted thermal strain ε calculated based on the current local temperature TL. y After that, the remaining "mechanical strain" component exceeded 150 microstrain for three consecutive cycles.

[0084] 4. Warning Generation and Output: When the platform determines that an anomaly has occurred, it automatically generates a warning message. The warning includes: the anomaly sensor ID, the anomaly type (corresponding to the rules above), the anomaly value, and the duration, and is highlighted and flashed in three dimensions at the corresponding position in the digital twin model.

[0085] The beneficial effect of this technical solution lies in transforming long-term health monitoring from a conceptual idea into an implementable and verifiable technical solution by disclosing the specific structure of the flexible thin-film sensing strip, the clearly defined installation process, and the baseline establishment and anomaly detection algorithm based on a dynamic statistical model. This solution can sensitively and reliably identify early signs of degradation in the repaired area, providing a quantitative basis for predictive maintenance, thereby ensuring the long-term operational safety and reliability of the pipeline repair section's heat tracing system.

[0086] In another technical solution, during step S6, the newly formed complete heat tracing circuit is electrically configured and operated by performing the following steps: A1. Independent zone power supply configuration: The heat tracing line segment corresponding to the public working area is electrically configured as an independently adjustable branch driven by an independent power supply control module; A2. Setting up a multi-stage operation strategy: In the digital collaborative management and control platform, at least two operation stages are preset for the independently adjustable branch: (i) Weld solidification and temperature stabilization stage: During the preset initial period after welding is completed, a constant first target temperature higher than the conventional antifreeze temperature is set, and the branch is controlled to work continuously to reach this temperature; (ii) Long-term antifreeze operation stage: After the initial period ends, the target temperature is switched to the conventional antifreeze temperature, and the branch is switched to an intermittent working mode based on ambient temperature sensing. A3. Strategy Execution and Monitoring: The digital collaborative management and control platform automatically switches the operation phase according to preset time nodes and controls the independent power supply control module to execute the corresponding power supply strategy; at the same time, it continuously monitors the operating current and temperature feedback data of the branch to ensure that it operates according to the strategy.

[0087] In the above technical solution, after system integration is completed in step S6, the electrical configuration and operation strategy of the newly formed complete heat tracing circuit are specifically defined. The specific implementation method is as follows: A1. Specific implementation of independent zone power supply configuration: After completing step S6 and forming a complete heat tracing circuit, an independent power supply control is configured for the heat tracing line segment covering the public work area within an explosion-proof distribution box that meets the requirements for hazardous area zoning. Specifically, the operation is as follows: First, under the condition of ensuring the safety of the main circuit being de-energized, an independent power supply control module is added to the distribution box. This module should be an intelligent electric heat tracing control unit that meets the explosion-proof rating of the pipeline area (e.g., explosion-proof Ex d IIC T4 or increased safety Ex e suitable for Zone 1), possessing continuous power regulation (e.g., via PWM or phase angle control) and current monitoring functions. The power lines at both ends of this heat tracing line are disconnected from the main circuit terminals and connected to the load output terminal of this independent module. Simultaneously, a controlled power supply is connected from the main power switch to the input terminal of this module. Thus, this heat tracing line segment is electrically configured as an independently controllable branch driven by the independent power supply control module. This control module connects to the digital collaborative management platform via its standard communication interface (e.g., RS-485 Modbus RTU).

[0088] A2. Specific implementation of setting up a multi-stage operation strategy: In the software of the digital collaborative management and control platform, two core operating stages are preset for the aforementioned independently controllable branches, and the parameter settings and logical basis are as follows: (i) Weld Curing and Temperature Stabilization Stage: This stage aims to provide a mild and stable thermal environment for the weld repair area. The first target temperature is set at 60℃±5℃. This temperature value is set based on the fact that it is significantly higher than the conventional antifreeze requirements, providing a certain amount of heat input to the weld area to facilitate hydrogen diffusion and escape, while being much lower than the conventional lower limit of post-weld heat treatment (PWHT) for common carbon steels (such as Q345R) (approximately >200℃), to avoid unnecessary thermal impact on the base material and the heating system itself. The preset initial period is set to 120 to 168 hours (5 to 7 days). This duration is based on engineering experience, providing a sufficient and continuous time window for initial stress relaxation and microstructure adjustment. During this stage, the platform controls an independent power supply control module to maintain the pipe surface temperature (based on the average readings of multiple temperature sensors near the weld, fed back by the aforementioned flexible thin-film sensor strip) stable at the first target temperature (e.g., 60℃), using closed-loop proportional-integral (PI) control to dynamically adjust the output power.

[0089] (ii) Long-term anti-freeze operation phase: Automatically switches to this phase after the initial phase. The standard anti-freeze temperature is set according to process safety requirements, for example, 5°C. This phase adopts an intermittent closed-loop operating mode based on both ambient temperature and pipeline temperature as dual criteria. The specific control logic is as follows: the platform collects the ambient temperature T in real time. env (From a certified explosion-proof ambient temperature sensor) and pipe surface temperature T pipe (From the sensor band). When T env Below 3℃ or T pipe When the temperature drops below 5°C, the platform activates this branch and maintains T. pipe PI control is performed with a target temperature of 5℃. When T env Temperatures consistently above 6°C and T pipe When the temperature remains above 8°C, the platform shuts down this branch. This hysteresis control logic prevents frequent operation near the critical temperature.

[0090] A3. Specific implementation of strategy execution and monitoring: The digital collaborative management and control platform automatically executes full-process control and monitoring according to preset strategies: 1. Automatic switching and execution: The platform starts timing when the branch is powered on for the first time after step S6 is completed. After the timing reaches the preset initial period (e.g., 168 hours), the platform automatically switches the control mode, target temperature and control logic to the "long-term anti-freeze operation stage" setting, and records the switching event in the operation log.

[0091] 2. Dual monitoring and security protection: Electrical safety monitoring: The platform reads the branch operating current I from the independent power supply control module in real time. act Compare it with the module's rated current I rated and the nominal current I of the heating wire heater Compare. If I act >1.5×I rated (Suspected short circuit) or I act <0.1×I heater (If there is an open circuit or severe poor contact), the platform will immediately issue the highest level alarm and instruct the module to be powered off.

[0092] Functional effectiveness monitoring: The platform analyzes the T-phase during power supply. pipe The rate of increase and steady-state value of T. If, after a period of continuous power supply (e.g., 30 minutes), T... pipe If the target temperature is still far from being reached, it is determined that the heating efficiency is too low, and a maintenance warning is issued.

[0093] 3. Data Recording, Traceability, and Maintenance Interface: The platform fully records all operational data for this branch, generating trend curves. Simultaneously, the platform provides a maintenance interface, allowing authorized personnel to make temporary, audited adjustments to parameters (such as target temperature and duration) for both phases under special circumstances (e.g., extreme cold weather forecasts).

[0094] The beneficial effects of this technical solution lie in achieving precise, goal-oriented thermal control by isolating the heat tracing branches in the repair area and implementing phased intelligent operation management. Clear parameter setting criteria and a closed-loop control logic with dual judgments ensure that both the goals of "weld curing and temperature stabilization" and "long-term freeze protection" can be achieved reliably and energy-efficiently. Full-process automated execution and multiple safety monitoring enhance the long-term reliability of the repaired joint while also ensuring the safety and efficiency of the heat tracing system itself.

[0095] In another technical solution, the digital collaborative management and control platform is further configured to perform data-driven health prediction of the heat tracing system during long-term system operation: the platform continuously records and analyzes the operating data of the independently controllable branch, including its historical power adjustment curve, the percentage of cumulative working time required to maintain the set temperature, and the temperature uniformity and strain data fed back by the flexible thin-film sensing strip; the platform has a built-in heat tracing system health prediction model, which uses the aforementioned operating data as input features; the model analyzes the changing trends of the features, quantitatively evaluates and outputs the current health index and expected remaining reliable life of the heat tracing system in the repair area; when the health index is lower than a preset threshold, or the expected remaining reliable life is shorter than a preset maintenance plan cycle, the platform generates a preventive maintenance warning in advance.

[0096] In the above technical solution, the digital collaborative management and control platform is further configured to perform data-driven health prediction of the heat tracing system during long-term system operation. Specifically: 1. Construction principles and framework of health prediction model This health prediction model aims to quantitatively assess the performance degradation of heat tracing systems in repair areas and predict their remaining reliable lifetime (RUL). The model is built upon the following core observations: performance degradation of heat tracing systems manifests in several measurable characteristics, including decreased operating efficiency (requiring more energy to maintain temperature), deterioration of heat distribution (worse uniformity), and abnormal mechanical conditions (interfacial strain). The model continuously monitors these characteristics and compares them to a baseline state when the system is healthy, thereby calculating a comprehensive health index (HI), and further mapping this to the remaining lifetime using an exponential decay law.

[0097] The specific mathematical framework of the health prediction model is as follows: Feature vector extraction: The platform periodically (e.g., daily) calculates and extracts a set of quantitative features characterizing the system state from the operating data of the independently adjustable branches and the data of the flexible thin-film sensing strip, denoted as feature vector F=[F1,F2,F3,F4], where: F1: Power demand trend, reflecting the rate of change in the energy required to maintain the set temperature.

[0098] F2: Workload stability, reflecting the volatility of the system's operating mode.

[0099] F3: Temperature field uniformity index, reflecting the degree of uniformity of heating in the repaired area.

[0100] F4: Interface strain level, reflecting the mechanical state of the bonding layer between the heat tracing wire and the pipe.

[0101] Health Index (HI) Calculation Model: The Health Index is a score between 0 and 100, obtained by calculating the weighted normalized offset of the current feature value relative to the system's health benchmark value. The formula is: HI = 100 - 100 × [w1 × ΔF1 + w2 × ΔF2 + w3 × ΔF3 + w4 × ΔF4], where w1, w2, w3, and w4 are the weight coefficients (w1 + w2 + w3 + w4 = 1) corresponding to the four features (F1, F2, F3, F4), and their magnitudes represent the degree of influence of each feature on the overall health score; ΔF1, ΔF2, ΔF3, and ΔF4 are the normalized offsets of the corresponding features.

[0102] Remaining reliable life (RUL) prediction model: Remaining life is predicted based on the decline of the health index using an exponential decline model. The calculation formula is: RUL (days) = T base ×365×exp(-k×(100-HI)), where T base is the statistical average expected lifespan (in years) of the heat tracing system under ideal health conditions, taken from the product design lifespan; k is a dimensionless decay constant used to quantify the severity of the impact of a decline in the health index on the remaining lifespan.

[0103] 2. The three specific stages of model implementation Based on the above model framework, the implementation of this function is divided into the following three stages: initial model deployment, online monitoring and feature calculation, and model evaluation and early warning. Details are as follows: (1) Initial model deployment and parameter setting Before the system is put into operation for the first time, a health prediction model needs to be deployed on the platform and its parameters need to be initially set.

[0104] Initial definitions of model input features (F1-F4): 1) F1 (Power Demand Trend): Defined as the long-term trend slope of the daily equivalent power percentage sequence for this branch. 2) F2 (Workload Stability): Defined as the long-term trend of the 4-week moving average of the weekly working time percentage for this branch. 3) F3 (Temperature Field Uniformity): Defined as the daily standard deviation of all effective temperature sensor readings in the corresponding area of ​​this branch. 4) F4 (Interfacial Strain Level): Defined as the 95th percentile of the daily residual mechanical strain of all strain sensors in the corresponding area of ​​this branch.

[0105] Model parameter initialization method: 1) Baseline value determination: Calculate the monthly average of each feature (F1-F4) based on the data from the month following the completion of welding repair and stable operation of the system for one month. This average is used as the initial health baseline value (B1, B2, B3, B4) for this specific system. For F3, since its baseline value B3 is usually small, to ensure the numerical stability of subsequent calculations, ΔF3 = F3 / C is used when calculating the offset, where C is an empirical "good uniformity threshold" (e.g., 2℃). 2) Initial weight allocation: In the absence of historical degradation data, the initial influence weights of the four features are set equally, i.e., w1=w2=w3=w4=0.25. 3) Initial lifetime parameter setting: Base lifetime T base The "design lifespan" (e.g., 10 years) specified by the manufacturer of the replaced heating cable product in their specifications should be directly adopted. The initial value of the attenuation constant k is set based on engineering experience, for example, k=0.015. This value means that when the Health Index (HI) drops from 100 to 70, the remaining lifespan is approximately 64% of the initial baseline lifespan (exp(-0.015×30) ≈ 0.64). 4) Warning threshold setting: The warning threshold for the Health Index (HI) is set to 70, and the warning threshold for the Remaining Life (RUL) is set to 180 days, providing advance notice for routine maintenance planning cycles.

[0106] (2) Online monitoring, feature calculation and model evaluation After the system enters long-term operation, the platform executes the following cyclical tasks: a. Daily Feature Calculation: Every morning, the platform automatically calculates the previous day's data. Specifically: 1) Trend Calculation: The trend slopes of F1 and F2 are calculated using the Theil-Sen robust regression algorithm on the past 90 days' sequence to resist outlier interference. 2) Valid Data Screening: Only sensor data (temperature: -50℃ to 200℃; strain: -2000 to 2000 microstrain) that have been in normal communication within the past 24 hours are used to calculate F3 and F4. 3) Feature Value Output: The daily F1 (power trend slope value), F2 (latest 4-week moving average trend value), F3 (daily standard deviation of temperature), and F4 (95th percentile of residual mechanical strain) are calculated.

[0107] b. Weekly Health Assessment: Every Monday, the platform summarizes the daily characteristic values ​​of the past 7 days and takes their arithmetic mean as the characteristic value (F1, F2, F3, F4) for the week. More specifically: 1) Calculate the normalized offset: ΔF1=|F1-B1| / B1; ΔF2=|F2-B2| / B2; ΔF3=F3 / C (C is a set empirical constant, such as 2℃); ΔF4=|F4-B4| / B4; 2) Calculate the current health index (HI): HI=100-100×(w1×ΔF1+w2×ΔF2+w3×ΔF3+w4×ΔF4); 3) Calculate the expected remaining reliable life (RUL): RUL (days)=T base ×365×exp(-k×(100-HI)).

[0108] c. Rolling Calibration of Model Parameters (Quarterly): The platform initiates a parameter calibration process every quarter. Specifically: 1) Weight Calibration: Based on historical data from the past quarter, the platform calculates the Spearman rank correlation coefficients between each feature sequence (F1-F4) and a surrogate health indicator sequence (such as "percentage of daily average power required to maintain the target temperature"), denoted as ρ1, ρ2, ρ3, ρ4. The weights of each feature are then updated according to the formula: wi new =|ρi| / (|ρ1|+|ρ2|+|ρ3|+|ρ4|), i=1,2,3,4. This method gives higher weights to features that are more correlated with the proxy index. 2) Attenuation constant calibration (optional): After the system has run for a full year, the attenuation constant k can be recalibrated by fitting the HI attenuation data of the first year with the actual running time, so that the lifetime prediction is more in line with reality.

[0109] (3) Early warning generation and output After completing the weekly health assessment, the platform immediately issues an early warning: if HI < 70, the platform generates a "Health Status Warning," which includes the current HI value, RUL value, and lists the most contributing abnormal characteristics (such as "significantly increasing power demand trend"). If RUL < 180 days, regardless of the HI value, the platform generates a "Remaining Life Warning," recommending preventative maintenance or inspection of the heating system in the area during the next planned shutdown window.

[0110] All warnings are prominently displayed on the platform's human-machine interface and automatically generate detailed reports including timestamps, data snapshots, analysis conclusions, and recommendations for operations and maintenance personnel to make decisions.

[0111] The beneficial effect of this technical solution lies in the fact that by disclosing a complete technical process, from initial parameter setting to specific feature calculation methods and online model calibration, the health prediction function of the heat tracing system can be achieved without relying on a large amount of historical failure data. This method establishes a personalized baseline using data from the initial stage of system commissioning and gradually improves the predictive accuracy by dynamically calibrating the model through running data. This provides those skilled in the art with a clear and operable path to build and implement data-driven predictive maintenance functions, thereby achieving proactive management of the long-term reliability of the heat tracing system in the pipeline repair area.

[0112] The technical effects of the present invention will be illustrated below through specific embodiments.

[0113] <Example 1> This embodiment simulates a synchronous maintenance operation on a refinery flare line to verify the safety and feasibility of the basic method and process.

[0114] 1. Task Object and Parameter Settings Pipeline: A section of venting pipeline made of 20# steel with a specification of Φ219.1mm×8.2mm has two localized corrosion defects.

[0115] Defects: Defect A (axial length 40mm, circumferential width 30mm, maximum depth 2.5mm); Defect B (axial length 25mm, circumferential width 20mm, maximum depth 2.0mm). The axial distance between the two defects is 350mm.

[0116] Objective: To simultaneously complete the pressurized welding repair of the two defects mentioned above and replace the heat tracing wire of the pipe section (approximately 2 meters in length).

[0117] 2. Specific implementation steps and data recording S1 / S2: After joint inspection, the planned common work area is a pipe section covering the two defects and the margin on both sides, with a total length of 1.2 meters. Remove the old insulation and anti-corrosion layer in this area.

[0118] S3: Lay new constant power heat tracing cables (temperature resistance rating 205℃) on both sides of the public work area. Use temporary support components (magnetic base + high temperature resistant ceramic fiber rope + ceramic clamps) to suspend and support the heat tracing cables crossing the area. The measured distance between the suspended section and the pipe surface is (105±10) mm.

[0119] S4: Wrap a 25mm thick ceramic fiber blanket around the edge of the public work area as a heat insulation barrier. On the heat tracing line fixed outside the barrier, install four K-type thermocouple monitoring points at the top (0°), sides (90°, 270°), and bottom (180°) of the pipe. The safe temperature threshold is set at 90℃.

[0120] S5: Defects A and B were welded sequentially using manual arc welding. During the welding process, the highest temperatures recorded at each monitoring point were as follows: 1) When welding defect A: the highest temperature at the top monitoring point was 87℃, and the highest temperature at the bottom monitoring point was 76℃. 2) When welding defect B: the highest temperature at the side (90°) monitoring point reached 91℃, triggering the threshold alarm, and welding was immediately interrupted. After the interruption, the temperature at the bottom monitoring point was the lowest (71℃), so a short section of tack welding was performed in the bottom area of ​​the pipe (where there were no defects). Welding of defect B was resumed and completed after the temperature at the side monitoring point dropped to 82℃.

[0121] S6: After welding, wait for the pipe surface temperature to drop below 45℃ before removing the heat insulation barrier. Apply silicone thermally conductive adhesive (approximately 1.5mm thick) to the weld area and secure the suspended section of the heating wire. The final measured insulation resistance of the heating circuit is 85MΩ, and the heating is uniform during power-on testing.

[0122] 3. Effect Verification This embodiment successfully completed welding and heat tracing installation in a single operation. Key verification points include: successfully interrupting welding before actual damage to the heat tracing wire (reaching the threshold at 91℃) through temperature monitoring; and achieving thermal management by changing the welding position, thus avoiding heat tracing wire damage in the "lay before welding" mode. Heat tracing was immediately restored after welding, eliminating the protection gap in the "weld before laying" mode. The entire operation took approximately 6 hours, meeting the requirements for limited shutdown windows.

[0123] <Example 2> This embodiment, based on embodiment 1, introduces a digital collaborative management and control platform to demonstrate predictive optimization and installation compliance verification functions.

[0124] 1. Platform and Model Construction Before the operation, a 3D scanner was used to obtain the defect point cloud, and a digital twin pipeline model containing two simplified pit defects was built in the platform.

[0125] The welding parameters (current 150A, voltage 23V, speed 0.12m / min) and environmental parameters (20℃) were set, and the platform performed a pre-simulation of the welding thermal process.

[0126] 2. Predictive optimization process When welding defect A occurs, the platform collects data in real time. When the prediction algorithm simulation calculation finds that, based on the current progress, the top monitoring point may exceed the 90℃ threshold in the next 18 seconds (at which time the actual temperature of the point is 85℃), the platform issues an audible and visual warning in advance: "Warning: The top monitoring point is predicted to exceed the temperature. It is recommended to pause or adjust the parameters."

[0127] Based on this warning, the operator paused welding for approximately 30 seconds before the actual temperature reached the threshold, resuming only after the predicted temperature curve had subsided. The actual peak temperature at this monitoring point ultimately only reached 88℃, failing to trigger the actual threshold alarm.

[0128] 3. Three-dimensional installation compliance verification After S3 is completed and before S5 begins, a 3D scanner is used to scan the site. The platform automatically compares the scanned point cloud with the digital twin model and generates a report. Report c (Suspension Distance and Coverage): The measured minimum suspension distance is 98mm (> the preset safety value of 95mm). The projection of the suspended section completely covers the two defect areas. Conclusion: Pass.

[0129] Report d (Barrier Location): Identified the actual edge of the insulation barrier, with deviations from the design position of: axial +3mm / -2mm, circumferential +1°. All within the allowable tolerances (axial ±10mm, circumferential ±5°). Conclusion: Passed.

[0130] The platform only unlocks the welding equipment and allows S5 to be executed after both reports are marked as "passed".

[0131] 4. Real-time Functionality Verification After construction is completed, the platform controls the power supply to the heat tracing circuit and executes the following simultaneously: (a) Infrared thermal imaging comparison: The correlation coefficient between the actual thermal distribution map and the expected baseline map is 0.94, and there are no abnormal hot or cold spots exceeding ±4℃. Conclusion: Good uniformity.

[0132] (b) Electrical parameter comparison: Operating current 12.1A (normal range 11.5-13.5A), insulation resistance 85MΩ (>20MΩ). Conclusion: Normal.

[0133] The platform's overall assessment: This synchronous construction is qualified.

[0134] <Example 3> This embodiment simulates the health monitoring and predictive maintenance functions of the system during long-term operation after the completion of the construction of Embodiment 1.

[0135] 1. Sensing system and initial baseline A flexible sensing strip integrating temperature and strain sensors (sensor spacing 200mm) was laid. After the system had been running stably for a month, the platform automatically calculated the initial health baseline values ​​(B1, B2, B3, B4) based on the aforementioned initial model deployment and parameter setting steps. For example, the temperature uniformity index baseline value B3 was calculated to be 0.8℃.

[0136] 2. Simulation of Health Monitoring and Prediction Process Year 1 (Health Status): The system is operating stably. The weekly Health Index (HI) is consistently above 92. The predicted Remaining Reliable Life (RUL) is consistently greater than 9 years.

[0137] Simulated anomaly introduction: On day 400, a slight aging of the local heating wires was simulated, leading to a decrease in thermal efficiency, and a slight delamination of the adhesive layer was simulated in one area.

[0138] Eigenvalue changes: F1 (Power Demand Trend): The slope of the daily equivalent power percentage trend changes from close to 0 to a slow positive growth.

[0139] F3 (Temperature Uniformity Index): Its weekly average value F3 gradually increases from the baseline value of 0.8℃ to 1.5℃. According to the model formula ΔF3=F3 / C (assuming C=2℃), the corresponding normalized offset ΔF3 increases from 0.4 to 0.75.

[0140] F4 (interfacial strain level): The 95th percentile of residual mechanical strain, F4, jumps and remains at a high level (approximately 120 microstrains).

[0141] Model output and early warning: Day 430: The platform calculated that the HI value dropped to 72, and the RUL was estimated to be 2.1 years. Because the HI was close to but had not yet fallen below the threshold of 70, the platform recorded the trend but did not issue a high-level warning.

[0142] Day 450: The HI value further decreased to 68 (<70), and the estimated RUL is 1.8 years. The platform immediately generated a "health status warning", pointing out: "The health index dropped to 68, mainly due to decreased temperature uniformity (F3) and abnormal interface strain (F4). It is recommended to check the heat tracing contact status and adhesive layer of the repair area."

[0143] Day 480: RUL is estimated at 1.2 years (approximately 438 days, still above the 180-day warning line). The platform continues to monitor.

[0144] Day 550: The estimated Remaining Life (RUL) is 165 days (<180 days). The platform generates a "Remaining Life Warning" and recommends scheduling preventative maintenance or replacement of the heating system in this area during the next planned parking window.

[0145] 3. Summary of Results This embodiment demonstrates how the monitoring system captures early performance degradation through quantitative features. The model can indicate maintenance needs months in advance (from day 450 to day 550 lifetime warning), validating data-driven predictive maintenance capabilities and realizing a shift from "post-failure repair" to "preventive maintenance."

[0146] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A method for simultaneous construction of live pipeline welding and leak-proof laying of heat tracing lines, characterized in that, Includes the following steps: S1. Joint Inspection and Planning: During the same operation window of the pipeline, a joint inspection is carried out on the target pipeline section to simultaneously identify the defective parts on the outer wall of the pipeline that need to be welded and repaired, as well as the sections covered by the heat tracing line that need to be re-laid, and to plan a common operation area that includes all the defective parts. S2. Expose common work area: Remove all existing coverings that obstruct welding operations in the common work area to fully expose the pipe surface in the area; S3. Pre-laying of heat tracing wire in sections: On the pipes on both sides of the public work area, complete the formal laying and fixing of the new heat tracing wire; The part of the new heat tracing wire that crosses the entire public work area is temporarily maintained above the outer surface of the pipe and kept in a non-adherent state to form a suspended section. S4. Heat-affected zone isolation and monitoring: A temporary heat insulation barrier is installed on the outer wall of the edge pipe in the public work area; a temperature monitoring point is installed near the barrier on the new heat tracing line that has been fixed outside the public work area, and a safe temperature threshold based on the heat tracing line's temperature resistance characteristics is set. S5. Controlled welding operation: The defective parts in the public work area are sequentially welded under pressure; during the welding process, the temperature of the temperature monitoring point is monitored in real time. When the temperature reaches the safe temperature threshold, the welding is immediately interrupted and resumed after it drops below the safe temperature threshold until all defective parts are welded. S6. System Integration: After the welding operation is completed and the surface temperature of the pipeline in the common work area cools down to a safe operating temperature, the temporary heat insulation barrier is removed; then, the slack heat tracing wire of the suspended section is laid and fixed tightly along the contour of the pipeline surface, including all new welds, so that it is electrically connected with the heat tracing wires fixed on both sides to form a complete heat tracing circuit.

2. The method for simultaneous construction of live pipeline welding and leak-proof laying of heat tracing lines as described in claim 1, characterized in that, In step S4: Temperature monitoring points are set on the fixed new heat tracing line at at least two different locations outside the public work area and around the pipeline to form a distributed temperature monitoring network; In step S5: the temperature data of each monitoring point in the distributed temperature monitoring network is collected and compared in real time; when the temperature of any monitoring point reaches the safe temperature threshold, welding is immediately interrupted; after welding is interrupted, the pipeline area corresponding to the location of the monitoring point with the lowest current temperature is selected as the work location for resuming welding.

3. The method for simultaneous construction of live pipeline welding and leak-proof laying of heat tracing lines as described in claim 1, characterized in that, In step S3, the temporary support is achieved through a temporary support assembly; the temporary support assembly includes a base that can be temporarily fixed to the outer wall of the pipe, and a high-temperature resistant flexible traction wire extending from the base to the upper part of the common work area; the free end of the flexible traction wire is provided with a high-temperature resistant clamp for gently clamping the heat tracing wire; by adjusting the effective length of the flexible traction wire, the clamped heat tracing wire segment is maintained at a preset safe distance above the surface of the pipe in the common work area and kept in a relaxed state.

4. The method for simultaneous construction of live pipeline welding and leak-proof laying of heat tracing lines as described in claim 3, characterized in that, The method relies on a digital collaborative management platform and includes predictive operation optimization and real-time functional verification steps implemented by the platform, as detailed below: Before step S1, there is also step S0, as follows: S0. Modeling: Before the operation, a digital twin model for thermal process simulation is established in the digital collaborative management and control platform based on the pipeline parameters, three-dimensional defect data and environmental parameters of the public operation area. Following step S6, there are also steps S7 and S8, as detailed below: S7. Predictive Optimization: During the welding process in step S5, the platform collects welding process parameters and temperature monitoring data in real time; based on the digital twin model and real-time data, it dynamically simulates the future temperature rise trend of each monitoring point through its built-in heat conduction prediction algorithm; when the simulation predicts that any monitoring point will exceed the safe temperature threshold, the platform issues an early warning before reaching the actual threshold and generates optimization adjustment suggestions for the welding sequence or parameters. S8. Real-time verification: After step S6 is completed and before the system resumes operation, the platform control will power on and debug the newly formed complete heat tracing circuit, and simultaneously execute: (a) Acquire the infrared thermal image of the common working area and compare it with the expected heat distribution benchmark image generated based on the digital twin model and design parameters to evaluate the uniformity and integrity of the heat tracing coverage; (b) Acquire the real-time operating current and insulation resistance parameters of the heat tracing circuit and compare them with the pre-stored normal range. The platform determines that the synchronous construction is qualified if and only if both comparison results (a) and (b) meet the requirements.

5. The method for simultaneous construction of live pipeline welding and leak-proof laying of heat tracing lines as described in claim 4, characterized in that, After step S3 is completed and before step S5 begins, a handheld or fixed 3D structured light scanner is used to scan the common working area and the suspended section; the 3D point cloud data obtained from the scan is automatically registered and compared with the digital twin model; the comparison generates and outputs two quantifiable verification reports: (c) Overhang Distance and Coverage Compliance Report: Based on the three-dimensional point cloud data, calculate the measured distance from each sampling point on the overhang section to the pipe surface; when the measured distance of all sampling points is not less than the preset minimum safety distance, and the overhang section completely covers the vertical projection area of ​​all defective parts in three-dimensional space, the report is passed; (d) Barrier Location Installation Compliance Report: Based on the three-dimensional point cloud data, identify the actual edge position of the temporary thermal insulation barrier and calculate its deviation from the design position specified in the digital twin model in the circumferential and axial directions of the pipeline; when the deviation values ​​in all directions do not exceed the preset allowable installation tolerance, the report is passed; The welding operation in step S5 can only proceed after both of the above verification reports show that they have passed.

6. The method for simultaneous construction of live pipeline welding and leak-proof laying of heat tracing lines as described in claim 5, characterized in that, In step S6, the suspended section is formally laid and fixed as follows: a flexible thermally conductive gap-filling adhesive layer is first coated on the surface of the pipe containing all new welds; while laying the suspended section heat tracing wire, a flexible thin-film sensing strip parallel to the heat tracing wire is placed between the thermally conductive gap-filling adhesive layer and the suspended section heat tracing wire; the flexible thin-film sensing strip integrates a distributed temperature sensor and a micro-strain sensor array; The signal cable and power cable of the flexible thin-film sensing strip are led out together and connected to the data acquisition module of the digital collaborative management and control platform. The control platform is configured to continuously monitor the temperature distribution uniformity and strain distribution data of the interface area between the adhesive layer and the heat tracing wire in the public working area during subsequent system operation, and establish a baseline of the health status of the heat tracing system in the area based on this. When monitoring data shows abnormal deviations, the platform issues a maintenance warning for that specific area.

7. The method for simultaneous construction of live pipeline welding and leak-proof laying of heat tracing lines as described in claim 6, characterized in that, In step S6, the newly formed complete heat tracing circuit is electrically configured and operated by performing the following steps: A1. Independent zone power supply configuration: The heat tracing line segment corresponding to the public working area is electrically configured as an independently adjustable branch driven by an independent power supply control module; A2. Setting up a multi-stage operation strategy: In the digital collaborative management and control platform, at least two operation stages are preset for the independently adjustable branch: (i) Weld solidification and temperature stabilization stage: During the preset initial period after welding is completed, a constant first target temperature higher than the conventional antifreeze temperature is set, and the branch is controlled to work continuously to reach this temperature; (ii) Long-term antifreeze operation stage: After the initial period ends, the target temperature is switched to the conventional antifreeze temperature, and the branch is switched to an intermittent working mode based on ambient temperature sensing. A3. Strategy Execution and Monitoring: The digital collaborative management and control platform automatically switches the operation phase according to preset time nodes and controls the independent power supply control module to execute the corresponding power supply strategy; at the same time, it continuously monitors the operating current and temperature feedback data of the branch to ensure that it operates according to the strategy.

8. The method for simultaneous construction of live pipeline welding and leak-proof laying of heat tracing lines as described in claim 7, characterized in that, The digital collaborative management and control platform is also configured to perform data-driven health prediction of the heat tracing system during long-term system operation: the platform continuously records and analyzes the operating data of the independently controllable branch, including its historical power adjustment curve, the percentage of cumulative working time required to maintain the set temperature, and the temperature uniformity and strain data fed back by the flexible thin-film sensing strip; the platform has a built-in heat tracing system health prediction model, which uses the aforementioned operating data as input features; the model analyzes the changing trends of the features, quantitatively evaluates and outputs the current health index and expected remaining reliable life of the heat tracing system in the repair area; when the health index is lower than a preset threshold, or the expected remaining reliable life is shorter than a preset maintenance plan cycle, the platform generates a preventive maintenance warning in advance.