Wedge-shaped blind plate rapid isolation process based on deep prefabrication and incomplete disassembly of valve

Abstract

The invention relates to a wedge-shaped blind plate rapid isolation process based on deep prefabrication and incomplete disassembly of a valve, which comprises the following steps of: deep precise prefabrication of a process pipe network: performing full-size scanning on an existing pipeline flange interface and a pipe gallery supporting structure by adopting a three-dimensional laser scanner to generate a millimeter-level precision reverse point cloud model; bIM collaborative design and collision detection of the newly added pipeline are carried out based on the reverse model; carrying out on-site modular prefabrication on the newly-added pipe section according to a design result, and carrying out cutting, beveling and assembly welding on the newly-added pipe section by using a movable precision machining tool on site; a hoop type rapid plugging blind plate is customized in advance; incompletely disassembling a single-side flange; and inserting and plugging the clamp type quick plugging blind plate. Through process innovation, the construction time is remarkably shortened, the operation risk in the limited space is greatly reduced, and the method is particularly suitable for pipeline reconstruction projects such as oil depots requiring short construction period and high safety.

Description

Technical Field

[0001] This invention relates to the field of pipeline upgrading and renovation engineering technology, and in particular to a rapid isolation process for wedge-shaped blind flanges based on deep prefabrication and incomplete valve disassembly. Background Technology

[0002] Pipeline upgrade and renovation projects in the petrochemical, energy storage and transportation sectors often face the dual challenges of tight deadlines (i.e., extremely short "window periods") and limited working space (such as inside canopies). The core safety prerequisite for such renovation projects is to achieve reliable and rapid isolation between the pipeline section to be renovated and the operating system.

[0003] Currently, the conventional pipeline isolation retrofit construction method in the industry usually follows this process: system shutdown and depressurization, energy isolation, removal of all bolts and corresponding connecting parts at flange connections, thorough cleaning of flange sealing surfaces, complete disassembly of existing valves, installation of isolation blind flanges, and finally installation and connection of new pipe sections. While this method is widely used, it suffers from a series of significant technical defects and implementation bottlenecks, specifically in the following aspects:

[0004] 1. Low construction efficiency and high cost. The entire process is cumbersome, especially the complete disassembly of large and heavy valves, which often requires the erection of large auxiliary facilities such as high-load-bearing gantry cranes, greatly increasing labor, equipment, and time costs. According to statistics, using the traditional "complete disassembly of double blind flange isolation" process, the average construction time for a single isolation point can reach more than 16 hours, which is difficult to meet the needs of emergency or short-cycle renovation projects.

[0005] 2. Significant safety risks. The hoisting, dismantling, and handling of heavy valves and pipe fittings in confined spaces pose a high risk of mechanical injury, such as falling parts, crushing collisions, etc., which seriously threaten the safety of personnel and equipment.

[0006] 3. Insufficient reliability of isolation operations. This is the main technical drawback of traditional methods:

[0007] Risk of seal failure: During installation, damage, corrosion, aging of gaskets (rings), or improper installation of the flange sealing surface can easily lead to poor blind flange sealing and media leakage. Industry data shows that approximately 5% of blind flange isolation operations fail due to installation quality issues.

[0008] Size compatibility issues: The dimensional fit between blind flanges and flanges requires strict adherence to specifications. Especially in high-pressure piping systems, there are higher requirements for the thickness, diameter, and pressure-bearing capacity of blind flanges, often necessitating customization. This not only increases costs but also, if there are processing errors or improper selection, can lead to a decrease in pressure-bearing capacity, creating safety hazards.

[0009] 4. The process itself causes secondary damage to the equipment. The process of completely disassembling the valve can easily cause irreversible damage to its critical sealing surfaces, affecting its reusability or lifespan. Specific reasons include:

[0010] Improper tools and operation: Using mismatched rigid tools (such as metal pry bars) or applying improper external force can easily scratch metal sealing surfaces or cause deformation or tearing of non-metallic seals.

[0011] Stress relief deformation: Valves that have been operating under pressure for a long time develop a microscopic fit on their sealing surfaces under stress. Complete disassembly and stress relief can cause changes in the shape of the sealing surfaces, making it difficult to restore the original sealing effect during reinstallation. On-site grinding or replacement is often necessary.

[0012] Human error: When disassembling precision components such as valve discs and valve seats, incorrect operating sequence or collisions may directly damage the sealing line or sealing components.

[0013] 5. High dependence on site conditions. Traditional methods require sufficient space for hoisting and large equipment operation, which is fundamentally contradictory to "confined space" working environments such as canopies, and is not feasible in many cases.

[0014] In summary, existing pipeline isolation and retrofit technologies suffer from inherent drawbacks such as long development cycles, high risks, poor reliability, and limited applicability. Therefore, there is an urgent need for a new, efficient, rapid, and reliable pipeline isolation process suitable for confined spaces to address the severe challenges of current oil depot and similar facility retrofit projects. Summary of the Invention

[0015] This invention aims to address the shortcomings of existing technologies by providing a rapid isolation process for wedge-shaped blind flanges based on deep prefabrication and incomplete valve disassembly.

[0016] To achieve the above objectives, the present invention adopts the following technical solution:

[0017] The rapid isolation process of wedge blind flanges based on deeply prefabricated and partially disassembled valves includes the following steps:

[0018] S1. Precise prefabrication of process piping network:

[0019] A handheld 3D laser scanner was used to perform a full-size scan of existing pipe flange interfaces and pipe gallery support structures, generating a reverse point cloud model with millimeter-level precision.

[0020] BIM collaborative design and clash detection of new pipelines based on reverse model;

[0021] Based on the design results, the new pipe sections are prefabricated on-site in a modular manner, with a prefabrication completion rate of no less than 90%. Only the hot work joints are retained. The prefabricated sections are treated with factory-level anti-corrosion and flange sealing surface protection.

[0022] Mobile precision machining tools were used on site to cut, bevele, and assemble the new pipe sections.

[0023] Custom-made clamp-type quick-sealing blind flanges are pre-designed, and their load-bearing capacity is calculated to meet sealing and emergency needs, achieving physical isolation between new and old pipelines and eliminating the risk of fire and explosion caused by oil residue;

[0024] S2. Incomplete disassembly of a single-sided flange: At the existing pipe flange connection that needs to be isolated, use a hydraulic torque wrench to loosen the bolts in stages, leaving only four diagonally positioned bolts. The bolt disassembly sequence is determined by a genetic algorithm optimization to ensure that residual stress is released evenly, retain the bolts to form a spatial constraint, and control the flange deflection angle to <0.5°.

[0025] S3. Insertion and sealing of clamp-type quick-sealing blind flange: Insert the clamp-type quick-sealing blind flange into the flange interface after step S2, and achieve quick centering and mechanical locking through the clamp structure, thereby completing the physical isolation of the pipeline.

[0026] Specifically, in step S1, the accuracy control indicators for the data acquired by the three-dimensional laser scanning include: the deviation of the existing flange end face spacing ≤ ±2mm, the error of the bolt hole center distance ≤ 0.3mm, and the three-dimensional accuracy of the spatial coordinates of the pipe gallery support point is ±1mm.

[0027] Specifically, mobile precision machining fixtures include magnetic track cutting machines, fully automatic beveling machines, and laser alignment instruments.

[0028] Specifically, the factory-grade anti-corrosion treatment includes sandblasting to Sa2.5 level and spraying a two-component epoxy primer with a dry film thickness of ≥250μm; the flange sealing surface is protected by a custom nylon end cap.

[0029] Specifically, the clamp-type quick-sealing blind flange in step S1 includes a blind flange body. The blind flange body has four slots evenly distributed around its circumference. A clamp is rotatably connected to the slot via a pin. The side of the blind flange body that inserts into the flange interface has a boss that matches the inner wall of the flange interface, and this side also has a sealing layer. The clamp has a mounting hole. The boss of the blind flange body is inserted into the flange interface, and the clamp is clamped onto the flange of the flange interface and fixed by the retained bolts.

[0030] The beneficial effects of this invention are:

[0031] 1. This invention revolutionizes the traditional cumbersome process of complete disassembly by combining the core technologies of "precise prefabrication of process piping" and "incomplete disassembly of single-sided flanges." The prefabrication section achieves a completion rate of over 90%, minimizing on-site workload; removing only some bolts while retaining positioning constraints significantly reduces flange separation and preparation time. By comprehensively applying these technologies, the construction time for a single isolation point can be significantly shortened from an average of over 16 hours using traditional methods, effectively meeting the stringent requirements of "short downtime" in projects such as oil depot renovations.

[0032] 2. This invention avoids the overall disassembly and heavy lifting of large valves, fundamentally eliminating the risk of serious mechanical injuries such as falling or crushing components. The use of a "clamp-type quick-sealing blind flange" achieves rapid isolation, supplemented by environmental monitoring and safety control measures, effectively controlling the risk of combustion and explosion during hot work connections. The "single-sided bolt retention" strategy provides stable spatial constraints for the flange during disassembly, preventing accidental slippage or instability and improving the safety of the operation.

[0033] 3. Based on 3D laser scanning reverse modeling and BIM collaborative design, millimeter-level precise matching of newly added prefabricated pipe sections and blind flanges with existing pipe flanges is ensured, eliminating problems such as insufficient pressure bearing capacity or installation difficulties caused by dimensional errors from the source. The specially designed clamp-type quick-sealing blind flange structure can generate optimized contact stress distribution under clamp tightening force, resulting in more reliable sealing performance. The optimized bolt disassembly sequence ensures uniform release of residual stress, protecting the integrity of the flange surface. Factory-grade corrosion protection, customized nylon end caps to protect the flange sealing surface, and avoidance of violent disassembly of valve sealing surfaces comprehensively protect the integrity of critical sealing pairs, reducing the probability of seal failure due to improper operation to an extremely low level.

[0034] 4. Modular prefabrication and rapid installation processes reduce reliance on on-site work space, making them particularly suitable for "restricted space" scenarios such as inside canopies. This breaks through the site limitations of traditional processes and provides an efficient, safe, and economical standardized solution for similar renovation projects. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the clamp-type quick-sealing blind flange structure of the present invention;

[0036] In the diagram: 1-Blind flange body; 2-Slot; 3-Clamp; 4-Boss; 5-Sealing layer; 6-Mounting hole;

[0037] The following will describe in detail, with reference to the accompanying drawings, embodiments of the present invention. Detailed Implementation

[0038] The present invention will be further described below with reference to embodiments:

[0039] like Figure 1 As shown, a rapid isolation process for wedge-shaped blind flanges based on deep prefabrication and incomplete valve disassembly includes the following steps:

[0040] S1. Precision Prefabrication of Process Piping Network: This stage aims to minimize on-site work and time through high-precision prefabrication.

[0041] A handheld 3D laser scanner was used to perform a full-size scan of the existing pipe flange interfaces and pipe gallery support structures, generating a reverse point cloud model with millimeter-level precision. The data accuracy control indicators obtained by the 3D laser scan include: the deviation of the existing flange end face spacing ≤ ±2mm, the error of the bolt hole center distance ≤ 0.3mm, and the three-dimensional accuracy of the spatial coordinates of the pipe gallery support points is ±1mm.

[0042] BIM collaborative design and collision detection for new pipelines based on reverse model; specifically, a 3D model of the new pipeline can be built in Autodesk Inventor, and the path can be optimized through collision detection to avoid spatial interference between the canopy steel structure and the existing pipeline.

[0043] Based on the design results, the newly added pipe sections are prefabricated on-site in a modular manner (the prefabricated sections include components such as elbows, tees, and flanges). The prefabrication completion rate is no less than 90%, with only the hot work connections remaining. The prefabricated sections undergo factory-level anti-corrosion treatment and flange sealing surface protection. Specifically, the factory-level anti-corrosion treatment includes sandblasting to Sa2.5 grade and spraying a two-component epoxy primer with a dry film thickness of ≥250μm, which reduces the risk of coating damage by 75% compared to traditional on-site coating. The flange sealing surface is protected by using customized nylon end caps to prevent scratches and contamination during transportation and hoisting.

[0044] On-site, mobile precision machining fixtures were used to cut, bevele, and assemble the new pipe sections. Specifically, the mobile precision machining fixtures included a magnetic track cutter (cutting accuracy ±0.3mm), a fully automatic beveling machine (beveling angle deviation <1°, blunt edge thickness error ±0.2mm), and a laser alignment instrument (flange surface parallelism deviation ≤0.1mm / m, bolt hole misalignment <0.3mm). During welding, an all-position automatic welding process and a closed-loop dimensional calibration system were adopted (establishing a "three-stage calibration" mechanism: factory calibration, simulated pre-assembly, and on-site fine-tuning).

[0045] Custom-made clamp-type quick-sealing blind flanges are pre-designed, and their load-bearing capacity is calculated to meet sealing and emergency needs, achieving physical isolation between new and old pipelines and eliminating the risk of fire and explosion caused by oil residue;

[0046] The clamp-type quick-sealing blind flange includes a blind flange body 1 (304L stainless steel base). Four slots 2 are evenly distributed around the circumference of the blind flange body 1. Clamps 3 are rotatably connected to the slots 2 via pins. On the side of the blind flange body 1 that inserts into the flange interface, there is a boss 4 (304L stainless steel base) that matches the inner wall of the flange interface. This side also has a sealing layer 5 (PTFE). The clamps 3 have mounting holes 6. The boss 4 of the blind flange body 1 is inserted into the flange interface, and the clamps 3 are secured to the flange of the flange interface and fixed by retained bolts. The clamp-type quick-sealing blind flange adopts a composite structure of 304L stainless steel base + PTFE sealing layer, achieving a contact stress gradient distribution under 0.5MPa pressure. Using a four-way clamp structure, it can achieve rapid centering and sealing, and rapid locking.

[0047] S2. Incomplete Disassembly of a Single-Sided Flange: At the flange connection of an existing pipeline requiring isolation, a hydraulic torque wrench is used to loosen the bolts in stages, leaving only four diagonally opposite positioning bolts. The bolt disassembly sequence is determined by a genetic algorithm to ensure uniform release of residual stress, maintain spatial constraints by retaining the bolts, and control the flange deflection angle to <0.5°. Specifically, a hydraulic torque wrench is used to disassemble the bolts of a single-sided flange of the existing pipeline, shortening the flange separation time. Using a hydraulic torque wrench, the operator can precisely control the torque value at each step, strictly following the sequence and staged torque calculated by the genetic algorithm to ensure uniform release of residual stress, effectively achieving the core objective of controlling the flange deflection angle to <0.5°.

[0048] S3. Insertion and sealing of clamp-type quick-sealing blind flange: Insert the clamp-type quick-sealing blind flange into the flange interface after step S2, and achieve quick centering and mechanical locking through the clamp structure, thereby completing the physical isolation of the pipeline.

[0049] The system adopts a "four-shift, three-rotation" system, with ≤6 workers per shift and emergency escape routes provided. Before hot work, an infrared combustible gas detector is used to continuously monitor for 30 minutes to ensure that the combustible gas concentration is <10%LEL.

[0050] Through the implementation of the above steps, this invention successfully reduces the construction time of a single isolation point from more than 16 hours in traditional methods, effectively reduces the risks of heavy hoisting operations and damage to the sealing surface, and significantly improves the reliability of isolation and sealing. It is particularly suitable for renovation scenarios with tight schedules and limited space.

[0051] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0052] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0053] The present invention has been described above by way of example. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present invention, or direct application to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A rapid isolation process for wedge-shaped blind flanges based on deeply prefabricated and partially disassembled valves, characterized in that, Includes the following steps: S1. Precise prefabrication of process piping network: A handheld 3D laser scanner was used to perform a full-size scan of existing pipe flange interfaces and pipe gallery support structures, generating a reverse point cloud model with millimeter-level precision. BIM collaborative design and clash detection of new pipelines based on reverse model; Based on the design results, the new pipe sections are prefabricated on-site in a modular manner, with a prefabrication completion rate of no less than 90%. Only the hot work joints are retained. The prefabricated sections are treated with factory-level anti-corrosion and flange sealing surface protection. Mobile precision machining tools were used on site to cut, bevele, and assemble the new pipe sections. Custom-made clamp-type quick-sealing blind flanges are pre-designed, and their load-bearing capacity is calculated to meet sealing and emergency needs, achieving physical isolation between new and old pipelines and eliminating the risk of fire and explosion caused by oil residue; S2. Incomplete disassembly of a single-sided flange: At the existing pipe flange connection that needs to be isolated, use a hydraulic torque wrench to loosen the bolts in stages, leaving only four diagonally positioned bolts. The bolt disassembly sequence is determined by a genetic algorithm optimization to ensure that residual stress is released evenly, retain the bolts to form a spatial constraint, and control the flange deflection angle to <0.5°. S3. Insertion and sealing of clamp-type quick-sealing blind flange: Insert the clamp-type quick-sealing blind flange into the flange interface after step S2, and achieve quick centering and mechanical locking through the clamp structure, thereby completing the physical isolation of the pipeline.

2. The rapid isolation process of wedge-shaped blind flanges based on deep prefabrication and incomplete valve disassembly as described in claim 1, characterized in that, In step S1, the accuracy control indicators for the data obtained by the three-dimensional laser scanning include: the deviation of the existing flange end face spacing ≤ ±2mm, the error of the bolt hole center distance ≤ 0.3mm, and the three-dimensional accuracy of the spatial coordinates of the pipe gallery support point is ±1mm.

3. The rapid isolation process of wedge-shaped blind flanges based on deep prefabrication and incomplete valve disassembly as described in claim 1, characterized in that, Mobile precision machining fixtures include magnetic track cutting machines, fully automatic beveling machines, and laser alignment instruments.

4. The rapid isolation process of wedge-shaped blind flanges based on deep prefabrication and incomplete valve disassembly as described in claim 1, characterized in that, Factory-grade corrosion protection includes sandblasting to Sa2.5 level and spraying a two-component epoxy primer with a dry film thickness ≥250μm; flange sealing surface protection is achieved by encapsulating with custom nylon end caps.

5. The rapid isolation process of wedge-shaped blind flanges based on deep prefabrication and incomplete valve disassembly as described in claim 1, characterized in that, The clamp-type quick-sealing blind flange in step S1 includes a blind flange body (1). The blind flange body (1) has four slots (2) evenly distributed around its circumference. A clamp (3) is rotatably connected to the slot (2) via a pin. The side of the blind flange body (1) that is inserted into the flange interface has a boss (4) that matches the inner wall of the flange interface. A sealing layer (5) is also provided on this side. The clamp (3) has an installation hole (6). The boss (4) of the blind flange body (1) is inserted into the flange interface, and the clamp (3) is clamped on the flange of the flange interface and fixed by the retained bolts.

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