A method for processing a sealing surface of a superhigh-pressure system connecting piece and an installation process method

Abstract

The application discloses a kind of ultra-high pressure system connecting piece sealing surface processing method, installation process method, the method includes: using grinding repair contrast card and pipeline connecting piece sealing surface are contrasted, if pipeline connecting piece sealing surface scratch depth is 12.5 μm~25 μm, using 80~200 mesh sandpaper along the circumferential direction of sealing surface is manually ground, and the roughness of sealing surface is not greater than Ra0.4 after grinding is polished using 1200 mesh sandpaper;If the scratch depth of the sealing surface of pipeline connecting piece is 25 μm~50 μm, using grinding mould is manually ground, and the roughness of sealing surface is not greater than Ra0.4 after using 200 mesh grinding paste grinding is polished using 1200 mesh sandpaper;If the scratch depth of the sealing surface of pipeline connecting piece is 50 μm~100 μm, using handheld electric grinding mould is electrically ground, and the roughness of sealing surface is not greater than Ra0.4 after grinding is polished using 1200 mesh sandpaper.The method is clear and definite to the sealing surface processing procedure standard and on-site installation procedure of connecting piece, with operability and guidance.

Description

Technical Field

[0001] This invention relates to the field of installation technology for ultra-high pressure systems in chemical plants, and in particular to a method for treating the sealing surface of connectors in ultra-high pressure systems and an installation process. Background Technology

[0002] The construction of existing chemical plants, especially polyolefin plants using high-pressure technology, falls within the new materials market sector, with broad development prospects. The construction of high-pressure systems is the core of the plant, and also the most technically demanding, specialized, and challenging part. Facing pressures ranging from 100MPa to 300MPa, the installation of all pipelines and connections presents a challenge. High precision in component sealing and installation demands meticulous attention to detail throughout the entire installation process. Summary of the Invention

[0003] The inventors discovered that during the installation process, if construction workers follow conventional installation methods, existing high-pressure methods and other device construction techniques are difficult to meet the quality requirements of project construction. At the same time, there is no systematic procedure in the industry for construction. In view of the above problems, this invention is proposed to provide a method for treating the sealing surface of ultra-high-pressure system connectors and an installation process to overcome or at least partially solve the above problems.

[0004] In a first aspect, embodiments of the present invention provide a method for treating the sealing surface of a connector in an ultra-high voltage system, which may include:

[0005] The sealing surface of the pipe connector is compared with the polishing and repair comparison card. If the scratch depth of the sealing surface of the pipe connector is less than 100μm, it is determined that the sealing surface of the pipe connector has local pitting corrosion or radial scratches; if the scratch depth of the sealing surface of the pipe connector is greater than 100μm, it is determined that the sealing surface of the pipe connector has deep scratches.

[0006] If the scratch depth on the sealing surface of the pipe connector is 12.5μm to 25μm, then use 80 to 200 grit sandpaper to manually grind along the circumference of the sealing surface until the roughness of the sealing surface is no greater than Ra0.4, and then use 1200 grit sandpaper to polish it.

[0007] If the depth of the scratch on the sealing surface of the pipe connector is 25μm to 50μm, then use a grinding jig for manual grinding, use 200-grit grinding paste to grind until the roughness of the sealing surface is no greater than Ra0.4, and then use 1200-grit sandpaper for polishing.

[0008] If the depth of the scratch on the sealing surface of the pipe connector is 50μm to 100μm, then use a handheld electric grinding jig to perform electric grinding until the roughness of the sealing surface is no greater than Ra0.4, and then polish it with 1200-grit sandpaper.

[0009] Optionally, before manual grinding using a grinding fixture, the following may also be included:

[0010] The grinding operation is carried out after comparing the grinding fixture with the sealing surface by means of light transmission or coloring to ensure that the contact area between the grinding fixture and the sealing surface is less than 75%.

[0011] Optionally, the roughness of the grinding fixture is not greater than Ra1.6.

[0012] Optionally, before performing electric grinding using a handheld electric grinding fixture, the process may further include: preparing a nylon fixture such that the contact area between the nylon fixture and the sealing surface is less than 75% before performing the grinding operation.

[0013] Optionally, if the scratch depth on the sealing surface of the pipe connector is greater than 100 μm, after determining that there is a deep scratch on the sealing surface of the pipe connector, the following may be further included:

[0014] The grinding fixture is made of ductile iron, and the roughness of the grinding fixture is not greater than Ra1.6;

[0015] The maximum clearance between the guide shaft and the tube is 0.2mm, the coaxiality between the guide shaft and the spherical surface is no more than 0.02mm, and a 1mm relief groove is left between the guide shaft and the spherical surface;

[0016] The spherical curvature is the same as that of the pipe connector. The contact surface is inspected using the light transmission method or the coloring method. After the contact surface is not less than 75%, the grinding operation is performed.

[0017] After grinding, measure the angular deviation with an angle gauge. If it is not up to standard, continue grinding. Once it is up to standard, polish with 1200-grit sandpaper.

[0018] Optionally, grinding paste may be applied to the sealing surface of the pipe fitting before the grinding operation.

[0019] Secondly, embodiments of the present invention provide an installation process method for an ultra-high voltage system, which may include:

[0020] The sealing surface of the pipe connector is treated using the ultra-high pressure system connector sealing surface treatment method described in the first aspect; wherein, the pipe connector includes: a flange and a metal lens gasket;

[0021] Seal the threads of flanges, pipelines, and bolts separately, and apply anti-seize agent to the threaded parts before installation;

[0022] Use hydraulic tightening tools to tighten the bolts that are hydraulically fastened.

[0023] Inspection of flange installation dimensions and sealing surface of metal lens gasket;

[0024] After all pipeline components are tightened, measure the distance between the ends of each installed pipeline to determine the length of the adjustment section and make corresponding adjustments.

[0025] Optionally, the method may also include: inspecting the threaded portion before installation; if the thread is scratched or the cross-section is incomplete, the cumulative length shall not exceed 3 / 4 turn, and the reduction in thread height shall not exceed 5%; otherwise, the defect shall be repaired into a smooth transition.

[0026] Optionally, the method may also include: performing magnetic particle inspection on the removed bolts, and replacing them if cracks are found;

[0027] And / or, perform a necking inspection on the removed bolts; replace them if the diameter is reduced by more than 1%.

[0028] Optionally, the inspection of the flange mounting dimensions and the sealing surface of the metal lens gasket may include:

[0029] Apply red lead powder to the sealing surfaces of the metal lens gasket and flange, rotate the metal lens gasket, and observe whether the contact line marks are uniform.

[0030] Use a vernier caliper to check the spacing between the corresponding flanges to ensure that the maximum deviation does not exceed 0.6mm; use a ruler in conjunction with the vernier caliper to check the concentricity of the two corresponding flanges to ensure that the deviation does not exceed 0.5mm.

[0031] The beneficial effects of the above-mentioned technical solutions provided in the embodiments of the present invention include at least the following:

[0032] This invention provides a method for treating the sealing surface of connectors in ultra-high pressure systems and an installation process. This method clearly defines the cleanliness standards and on-site installation procedures for pipelines and components, making it more operable and instructive. At the same time, the method for adjusting pipe sections is advanced and accurate.

[0033] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0034] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0035] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0036] Figure 1 This is a flowchart of the sealing surface treatment method for ultra-high voltage system connectors provided in this embodiment of the invention;

[0037] Figure 2 This is a comparison card of localized shallow point defects provided in an embodiment of the present invention;

[0038] Figure 3 This is a circumferential scratch comparison card provided in an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of the spherical ruler for detecting the metal lens pad provided in an embodiment of the present invention;

[0040] Figure 5 This is a schematic diagram of the parameters of the grinding fixture provided in an embodiment of the present invention;

[0041] Figure 6 This is a flowchart illustrating the installation process of an ultra-high voltage system provided in an embodiment of the present invention.

[0042] Figure 7 This is a schematic diagram of the centering quality inspection tool provided in an embodiment of the present invention;

[0043] Figure 8 This is a schematic diagram of the preparation of the closed segment provided in an embodiment of the present invention. Detailed Implementation

[0044] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0045] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "far," "near," "front," and "rear," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are 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, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] This invention provides a method for treating the sealing surface of connectors in ultra-high pressure systems. This method requires standardized sealing surface treatment of the connectors in a clean room to ensure that the connectors can meet the design pressure requirements of 10.0–360 MPa. (Refer to...) Figure 1 As shown, the method may include:

[0048] Step S10: Compare the grinding repair comparison card with the sealing surface of the pipe connector. If the scratch depth on the sealing surface of the pipe connector is less than 100μm, proceed to step S11; otherwise, proceed to step S12.

[0049] The pipe connectors in this embodiment of the invention include flanges and metal lens gaskets. During pipe installation in ultra-high pressure systems, no pits or radial scratches are allowed near the sealing surfaces of the flanges and lens gaskets. After grinding, the surface roughness of the sealing surfaces should not exceed Ra0.4. (Refer to...) Figure 2 and Figure 3 As shown, a comparison is made based on a local point-like shallow defect comparison card and a circumferential scratch comparison card to determine the scratch depth and perform corresponding grinding treatment.

[0050] The scrapping standards for the above-mentioned metal lens pads in this embodiment of the invention are as follows: After the lens pad surface has been ground multiple times, it must maintain a spherical state. If the overall thickness is reduced by more than 1 mm, it shall be scrapped; if the total thickness reduction of all lens pads in a pipeline is greater than 5 mm, the lens pads shall be replaced or the piping system shall be adjusted; if cracks are found when the surface of the lens pad is inspected by magnetic particle inspection, it shall be replaced.

[0051] In this embodiment, the metal lens pad is fabricated as follows: Figure 4 The spherical ruler shown can be inspected using either the light transmission method or the coloring method.

[0052] Step S11: Determine if there are localized pitting corrosion or radial scratches on the sealing surface of the pipe connection.

[0053] Step S12: Determine if there are deep scratches on the sealing surface of the pipe connection. For deep scratches, a grinding jig needs to be processed, and grinding paste is applied to the surface to grind the flange sealing surface until the surface scratches are eliminated. Then, polish with 1200-grit sandpaper, as described in detail in steps S16 to S19.

[0054] Step S13: If the scratch depth of the sealing surface of the pipe connector is 12.5μm~25μm, use 80~200 grit sandpaper to manually grind along the circumference of the sealing surface until the roughness of the sealing surface is no greater than Ra0.4, and then use 1200 grit sandpaper to polish it.

[0055] In this step, depending on the depth of the defect, continuously grind along the circumference of the sealing surface with 80-200 grit sandpaper until the surface is free of defects, and then polish with 1200 grit sandpaper. When grinding the lens pad, continuously grind the entire spherical surface in the same direction with 200 grit sandpaper. After the defect is eliminated, polish the spherical surface in the same way with 1200 grit sandpaper.

[0056] Step S14: If the scratch depth on the sealing surface of the pipe fitting is 25μm to 50μm, manually grind it using a grinding jig. Grind with 200-grit polishing compound until the roughness of the sealing surface is no greater than Ra0.4, then polish with 1200-grit sandpaper. Use the light transmission method or coloring method for comparison to ensure that the contact area between the grinding jig and the sealing surface is less than 75% before proceeding with the grinding operation. The roughness of the grinding jig should not exceed Ra1.6.

[0057] Before using the fixture in this step, it is essential to check that the angle of the fixture matches the angle of the surface being ground. This can be done using methods such as coloring or light transmission. The contact area should not exceed 75%, and the surface roughness should not exceed Ra1.6. After passing the inspection, grind the surface with 200-grit polishing paste until there are no defects, and then polish with 1200-grit sandpaper.

[0058] Step S15: If the scratch depth on the sealing surface of the pipe connector is 50μm to 100μm, perform electric grinding using a handheld electric grinding fixture. Grind until the roughness of the sealing surface is no greater than Ra0.4, then polish with 1200-grit sandpaper. In this step, a nylon fixture must first be made (with the angle consistent with the angle of the surface being ground) so that the contact area between the nylon fixture and the sealing surface is less than 75% before grinding. In practice, a lathe must be used for grinding, and a spherical turning tool must be used for finish turning. Grind with 200-grit sandpaper until the surface is free of defects. After removing indentations and defects, the final roughness of the sealing surface must not exceed Ra0.4, and then polish with 1200-grit sandpaper.

[0059] Step S16: Use ductile iron to make a grinding fixture. The surface roughness of the grinding fixture should not exceed Ra1.6. The grinding fixture material is usually ductile iron with a surface roughness not exceeding Ra1.6.

[0060] Step S17: The maximum clearance between the guide shaft and the tube is 0.2mm, the coaxiality between the guide shaft and the spherical surface is no greater than 0.02mm, and a 1mm relief groove is left between the guide shaft and the spherical surface. (Refer to...) Figure 5 As shown, the maximum gap between the guide shaft and the tube is 0.2mm, the coaxiality between the guide shaft and the spherical surface is no more than 0.02mm, and a 1mm relief groove is left between the guide shaft and the spherical surface.

[0061] Step S18: The spherical curvature is the same as that of the pipe fitting. Use the light transmission method or coloring method to inspect the contact surface. After ensuring that the contact surface is not less than 75%, proceed with the grinding operation. Before performing the grinding operation, apply grinding paste to the sealing surface of the pipe fitting.

[0062] Step S19: After grinding, measure the angle deviation with an angle ruler. If it is not up to standard, continue grinding. If it is up to standard, polish with 1200 grit sandpaper.

[0063] Based on the same inventive concept, this invention also provides an installation process method for an ultra-high voltage system, referring to... Figure 6 As shown, the method may include the following steps:

[0064] Step S20: Apply the above-described method for treating the sealing surface of the pipe connector to the sealing surface of the pipe connector; wherein the pipe connector includes: flange and metal lens gasket;

[0065] Step S21: Clean the threads of the flange, pipeline and bolt respectively, and apply anti-seize agent to the threaded parts before installation.

[0066] Step S22: Before installation, inspect the threaded part. If the thread is scratched or the cross-section is incomplete, the cumulative length shall not exceed 3 / 4 turn and the reduction in thread height shall not exceed 5%. Otherwise, the defect shall be repaired into a smooth transition.

[0067] It should be noted that when screwing the threaded flange into the pipe end of an ultra-high pressure pipeline, care should be taken to prevent jamming. If slight resistance is encountered, the flange should be stopped immediately and the pipe removed. The area should then be cleaned again; forced assembly is prohibited. When installing the flange onto the pipeline, the pipe end must protrude from the flange plane by at least one turn.

[0068] Step S23: Perform magnetic particle inspection on the removed bolts. If cracks are found, replace them.

[0069] Step S24: Perform a necking inspection on the removed bolts. Replace them if the diameter is reduced by more than 1%.

[0070] Step S25: Install bolts with hydraulic tightening by using hydraulic tightening tools. It should be noted that bolts without hydraulic tightening should be tightened using a torque wrench.

[0071] Step S26: Inspection of flange installation dimensions and sealing surface of the metal lens gasket. Specifically, first, apply red lead powder to the sealing surfaces of the metal lens gasket and the flange. Rotate the metal lens gasket at a small angle (15°) and observe whether the contact line marks are uniform. Then, use a vernier caliper to check the corresponding flange spacing (select four points spaced 90° apart) to ensure that the maximum deviation does not exceed 0.6mm. Use a ruler in conjunction with the vernier caliper to check the concentricity of the two corresponding flanges to ensure that the deviation does not exceed 0.5mm.

[0072] It should be noted that flange sealing parts should be documented according to the pipeline single-line diagram numbering, and equipment sealing parts should be documented with a simplified equipment structural diagram and numbered. After repairing the sealing surface, apply Vaseline for protection. When disassembling and assembling bends, first record the coaxiality and parallelism deviations of the sealing surfaces on both sides, and align and initially tighten them simultaneously during installation. During the tightening of bolts using a hydraulic tensioner, check the hydraulic system and accessories for leaks and ensure the accessories are intact. From the time the tightening pressure reaches the predetermined pressure until the operator completes tightening the nuts, there should be no system leakage or oil pressure drop (confirmed via pressure gauge). Pressure release can only begin after the acceptance or monitoring personnel confirm that each nut is properly tightened, and inspection and recording should be performed. For each sealing surface, data such as tightening pressure (torque), bolt elongation, parallelism between the flange and lens gasket, and coaxiality between pipes must be recorded.

[0073] Refer to Tables 1 and 2 below. Figure 7 As shown, there is a quality process control table and an installation tolerance table.

[0074] Table 1. Quality Process Control Table for Alignment

[0075]

[0076] Table 2 Installation Allowable Error Table

[0077]

[0078]

[0079] Step S27: After all pipeline components are tightened, measure the distance between the ends of each installed pipeline to determine the length of the adjustment section and make corresponding adjustments.

[0080] It should be noted that reserved sections are generally provided in both the horizontal and vertical sections of the pipeline route, and the dimensions of these sections are determined on-site. When calculating the length of the adjustment section, it is important to ensure that the pipe spacing is smaller than the thickness of the lens gasket. The pipe section cutting marks measured on-site must be clear and distinct, with a 5mm machining allowance. Then, mark the pipe number and material, and make two confirmation test marks at 180 degrees at 250mm from the pipe end. For pipes less than 1 meter in length, make a confirmation test mark in the middle of the pipe section. Then transport the pipe and machine the threads under the guidance of the external party. Before installation, the dimensions must be confirmed according to the confirmation test marks.

[0081] Compared with the prior art, the method provided in this invention has the following advantages: first, the standard and on-site installation procedures for grinding the sealing surfaces of pipes and components are clear and easy to follow, making it more operable and instructive; second, the method for adjusting pipe sections is advanced and accurate; and third, the self-developed and assembled complete set of testing tools improves efficiency and accuracy.

[0082] The processing and assembly testing toolkits used in the ultra-high voltage system installation process of this invention are shown in Table 3:

[0083] Table 3. Processing and Assembly Complete Testing Tool Kit

[0084]

[0085]

[0086] In a specific example, the implementation and application of XXX Company's 200,000-ton / year EVA project.

[0087] 1. Perform sealing treatment and on-site installation of pipes and components within the cleanroom.

[0088] 1. Treatment of pipe section sealing surfaces

[0089] (1) Before installation, remove the fixed supports set up for transportation at the storage point and immediately carry out the sealing surface treatment of the pipe section; all pipe sections that arrive have their threads, flanges, lens gaskets, bolts and other sealing surfaces treated with anti-rust grease, and the sealing surface treatment is carried out on a clean workbench covered with rubber.

[0090] (2) Remove the protective caps at both ends of the pipe section and treat the sealing surfaces. Use acetone, kerosene, etc. to remove the rust-preventive liquid from the pipe. When treating the sealing surfaces, use a clean silk cloth to wipe back and forth to ensure that the pipe is unobstructed and free of foreign objects.

[0091] (3) After the sealing surface is treated, the removed protective cap should be reinstalled on the pipe to prevent it from getting dirty or damaged during transportation to the site.

[0092] (4) After cleaning, thread-specific lubricant should be applied to the pipe ends and flange threads.

[0093] 2. Pre-installation treatment of pipe fittings and seals

[0094] (1) Before pipe installation, unscrew the protective caps at both ends and check whether the inside of the pipe is clean and free of foreign objects. Keep the inside of the pipe clean and unobstructed. Each pipe section is treated as an independent unit during installation. High-pressure sealing components (such as lens gaskets, double-ended bolts and nuts) are taken out of the warehouse by the construction personnel and strictly cleaned before installation.

[0095] (2) After cleaning the pipe threads, seal them with plastic film before assembling the flange. For standard pipe threads, use plastic caps. Wipe the sealing surface clean with a cleaning cloth (degreased yarn or silk cloth), and check to ensure the surface is rust-free and smooth. No small scratches are allowed when viewed in direct or tangential light. For lens gasket sealing surface treatment, apply protective grease to the sealing surface before installation. Do not clean before installation. After sealing surface treatment, the lens gasket should be coated with white grease for protection. When placing the lens gasket, use a white cloth as a pad to prevent damage to its sealing surface.

[0096] (3) Before installing the threaded flange, carefully check whether the materials match the drawings to ensure that the materials are accurate. Apply MoS2 lubricant to the threaded end of the pipe after cleaning.

[0097] (4) During installation, remove the protective cap or cover from the threaded end of the component, remove the grease or anti-corrosion (coating) coating from the threads and sealing surfaces, leaving only a thin protective film. Then, wipe the sealing surface around the circumference with a clean silk cloth until the bright metal is exposed. Check the surface for smoothness, rust, and scratches. Even minor scratches in the radial or tangential direction are not allowed. Minor scratches can be removed by grinding with fine diamond grit (120#) sandpaper stretched on a plastic cone at a 140° angle. The cone should be clamped in the chuck of a manual drill.

[0098] (5) Before installing pipelines / fittings, the installers shall check and confirm that the ends of the pipelines are marked with the correct identification marks and that the imprinted marks are complete. No unmarked parts shall be installed.

[0099] 3. On-site installation of flange connections

[0100] The installation sequence for the flange connection is as follows:

[0101] (1) Protect the ends of the pipes delivered to the site properly, hoist them smoothly, and prevent them from being bumped or knocked.

[0102] (2) After removing the protective pipe fittings, flanges and lens gaskets, the connection pairs to be installed shall be numbered and confirmed and recorded on the connection pair confirmation form (appendix). Use an appropriate solvent to remove dirt from the surface again, leaving only a thin layer of grease film to prevent corrosion of the exposed metal sealing surface, especially the pipe end threads. Use a new, clean, lint-free silk cloth to wipe them. After the sealing surface is cleaned, confirm and record it on the connection pair confirmation form (appendix).

[0103] (3) Apply a thin layer of MoS2-containing grease to the threaded portion of the flange and each threaded end of the pipe, and install the threaded flange to each end of the pipe. The threads at the pipe end are fine threads. When screwing the flange to the pipe end, be especially careful and never force it to assemble, to prevent the threads from jamming and causing the material to be scrapped. Ensure that the sealing surface and threads of the pipe are kept absolutely clean.

[0104] (4) Loosely install the lens gasket on the sealing surface of the pipeline to be connected, move the gasket back and forth slightly to determine that the gasket is properly installed, then install the bolts, tighten the nuts, and initially align the flange connection.

[0105] (5) Tighten the bolts gently to create frictional contact between the lens gasket and the sealing surface of the pipe end. Ensure that the lens gasket is centered and that the two flanges are concentric and parallel. Be especially careful when aligning, as alignment is closely related to sealing performance.

[0106] (6) Connect each pipe segment or straight section so that the centerline of the pipe segment forms a straight line extending to the next bend / joint, traversing the entire length of the pipeline without any bends. The lateral and radial deviations of the entire system shall meet the following requirements. Figure 2 Requirements in Table 2:

[0107] (7) Special installation requirements

[0108] If any part of the ultra-high pressure pipeline is temporarily unattended on site and under construction, the threaded parts or components of the ultra-high pressure pipeline section should be protected with thread protection devices. Ensure that all sealing surfaces and ultra-high pressure pipeline components are free of impurities. If these components are temporarily unattended, use measures such as plastic caps for protection.

[0109] (8) Tighten the bolts

[0110] All bolts on the ultra-high pressure interface flange are bolted using a special hydraulic wrench as shown in the figure below. The specified hydraulic pressure is provided to the lens gasket and the pipe surface to form the required load for sealing. The torque value (Table 4 below) should be preset on the pressure gauge of the hydraulic pump.

[0111] Table 4 Maximum torque required for bolt tightening

[0112]

[0113] During the bolt tightening process, the alignment and leveling of the flanges on both sides of the interface should be checked frequently. Vernier calipers should be used at four points on the flange during the check. The final dimensions and tolerances of the tightened bolts should be checked at each of the four quarter turns, and the results should be recorded. Within the allowable tolerance range, ensure that all surfaces of the flange are installed parallel. This process must be confirmed and signed and recorded on the Connection Confirmation Form (Appendix).

[0114] (9) Flange alignment and tightening

[0115] Step 1: When installing the lens gasket, first use two pins spaced apart on the bottom to insert the sleeve to position the lens gasket. Then, use three bolts to secure the lens gasket (do not tighten too much, just enough to prevent it from falling off). Use a lens installation aid or a suitable lens clamp to place the lens gasket in the exact center. Then, remove the two pins, insert the bolts, and gently tighten them to create friction contact between the lens gasket and the sealing surface of the pipe end. Use a ruler or internal sensor to carefully observe whether the center position of the lens gasket is concentric and parallel to the two flanges. Ensure that the lens gasket is centered and the two flanges are concentric and parallel. Extra care must be taken during alignment, as it is closely related to sealing performance.

[0116] The second step is to accurately center the device and then tighten the wrench by 1 / 4 turn. The error of measuring 4 points in 4 different directions, radial and lateral, should not exceed 1 mm. The measured values ​​should be recorded on the confirmation sheet.

[0117] The third step is to tighten the bolts using a special hydraulic tensioning system, performing the tightening simultaneously. After tightening, check the alignment again.

[0118] (10) Final determination

[0119] After the final tightening is completed using a torque device, each completed interface is checked by wrapping a strip of paper around the two flanges at the calibrated gap. At high-pressure pipe connections, any identical flanges are checked using this method. The construction worker keeps a record of each completed connection interface. All interfaces and individual checks are recorded and filed.

[0120] II. Handling of On-site Pipeline Adjustment Sections

[0121] (1) After the final tightening of the pipe components is completed, the measurement of the required length of the adjustment section on site will begin.

[0122] (2) The field adjustment section is also indicated in the pipe detail drawing. The distance between the ends of each installed pipe (i.e., the gap between each field adjustment section) should be carefully measured. This length should represent the actual fabrication length of the field adjustment section.

[0123] (3) The length of the adjustment section should be measured, referring to... Figure 8 The diagram shown illustrates the preparation of the closed section, clearly indicating the detailed drawing number and identification name of the closed section. After completion, it is reviewed and signed by the on-site construction technician.

[0124] (4) Before the on-site adjustment section arrives at the site, install thread protection facilities on the ends of the pre-installed pipes that match the on-site adjustment section, and remove them when the on-site adjustment section is installed.

[0125] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. This disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A method for treating the sealing surface of a connector in an ultra-high voltage system, characterized in that, The ultra-high pressure system is designed for pressures of 10.0 MPa to 360 MPa, and the method includes: The sealing surface of the pipe connector is compared with the polishing and repair comparison card. If the scratch depth of the sealing surface of the pipe connector is less than 100μm, it is determined that the sealing surface of the pipe connector has local pitting corrosion or radial scratches; if the scratch depth of the sealing surface of the pipe connector is greater than 100μm, it is determined that the sealing surface of the pipe connector has deep scratches; wherein, the pipe connector includes a flange and a metal lens gasket. If the depth of the scratch on the sealing surface of the pipe connector is 12.5μm~25μm, then use 80~200 grit sandpaper to manually grind along the circumference of the sealing surface until the roughness of the sealing surface is no greater than Ra0.4, and then use 1200 grit sandpaper to polish it. If the depth of the scratch on the sealing surface of the pipe connector is 25μm~50μm, first use the light transmission method or the coloring method for comparison, so that the contact area between the grinding jig and the sealing surface is less than 75%, then use the grinding jig for manual grinding, and then use 200-grit grinding paste to grind until the roughness of the sealing surface is no greater than Ra0.4, and then use 1200-grit sandpaper for polishing. If the depth of the scratch on the sealing surface of the pipe connector is 50μm~100μm, a nylon jig is first made so that the contact area between the nylon jig and the sealing surface is less than 75%, and then a hand-held electric grinding jig is used for electric grinding. After grinding until the roughness of the sealing surface is no greater than Ra0.4, it is polished with 1200-grit sandpaper. If the depth of the scratch on the sealing surface of the pipe connector is greater than 100μm, a grinding fixture shall be made of ductile iron, and the roughness of the grinding fixture shall not be greater than Ra1.

6. The maximum clearance between the guide shaft and the tube is 0.2mm, the coaxiality between the guide shaft and the spherical surface is no more than 0.02mm, and a 1mm relief groove is left between the guide shaft and the spherical surface; The spherical curvature is the same as that of the pipe connector. The contact surface is inspected using the light transmission method or the coloring method. After the contact surface is not less than 75%, the grinding operation is performed. After grinding, measure the angular deviation with an angle gauge. If it is not up to standard, continue grinding. Once it is up to standard, polish with 1200-grit sandpaper.

2. The method according to claim 1, characterized in that, The roughness of the grinding fixture is no greater than Ra1.

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3. The method according to claim 1, characterized in that, Before performing the grinding operation, apply grinding paste to the sealing surface of the pipe connection.

4. A method for installing an ultra-high voltage system, characterized in that, include: The sealing surface of the pipeline connector is treated using the sealing surface treatment method for ultra-high pressure system connectors as described in any one of claims 1 to 3; wherein the pipeline connector includes: a flange and a metal lens gasket; Seal the threads of flanges, pipelines, and bolts separately, and apply anti-seize agent to the threaded parts before installation; Use hydraulic tightening tools to tighten the bolts that are hydraulically fastened. Inspection of flange installation dimensions and sealing surface of metal lens gasket; After all pipeline components are tightened, measure the distance between the ends of each installed pipeline to determine the length of the adjustment section and make corresponding adjustments.

5. The method according to claim 4, characterized in that, Also includes: Before installation, inspect the threaded part. If the thread is scratched or the cross-section is incomplete, the cumulative length shall not exceed 3 / 4 turn and the reduction in thread height shall not exceed 5%. Otherwise, the defect shall be repaired into a smooth transition.

6. The method according to claim 4, characterized in that, Also includes: Perform magnetic particle inspection on the removed bolts; replace them if cracks are found. And / or, perform a necking inspection on the removed bolts; replace them if the diameter decreases by more than 1%.

7. The method according to claim 4, characterized in that, The inspection of the flange installation dimensions and the sealing surface of the metal lens gasket includes: Apply red lead powder to the sealing surfaces of the metal lens gasket and flange, rotate the metal lens gasket, and observe whether the contact line marks are uniform. Use a vernier caliper to check the spacing between the corresponding flanges to ensure that the maximum deviation does not exceed 0.6mm; use a ruler in conjunction with the vernier caliper to check the concentricity of the two corresponding flanges to ensure that the deviation does not exceed 0.5mm.

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