A grinding and repair device and process for the sealing surface of a high-pressure main steam valve.

Abstract

This invention relates to the field of high-pressure main steam valve technology, particularly to the field of IPC B24B7, and more specifically, to a grinding and repair device and process for the sealing surface of a high-pressure main steam valve. The grinding and repair device includes a grinding frame (1), a grinding tool (2), a pressure-adjusting seat (3), and a fixing component (4). The grinding and repair device is fixed inside the valve body (6) of the high-pressure main steam valve. The fixing component (4) is fixed to the positioning plate (5) by fastening bolts (401) and threaded bottom holes (402). The grinding tool (2) is inserted into the grinding tool (1) and secured by the pressure-adjusting seat (3). The self-adhesive sandpaper has a mesh size of 240, and the compression rate of the compression spring is 40-60%, which can effectively improve the smoothness and uniformity of the sealing surface.

Description

Technical Field

[0001] This invention relates to the field of high-pressure main steam valve technology, particularly to the field of IPC B24B7, and more specifically, to a high-pressure main steam valve sealing surface grinding and repair device and process. Background Technology

[0002] The high-pressure main steam valve is a protective device used by steam turbines to quickly cut off the steam supply and shut down the turbine. Its structure is similar to a stop valve. It is controlled by pressure oil to close and open quickly. However, after long-term use, the end face of the high-pressure main steam valve will wear. When the wear is significant, it needs to be ground and repaired. Since the main valve seat of the high-pressure main steam valve is welded to the valve body, it cannot be removed separately for grinding and repair of the sealing surface. Grinding and repair must be performed on-site inside the valve body.

[0003] The existing end face grinding tools for repairing high-pressure main steam valves typically use a grinding disc to grind and repair the end face of the high-pressure main steam valve. However, due to the varying lengths and heavy weight of high-pressure main steam valves, it is cumbersome for workers to manually adjust the distance between the high-pressure main steam valve and the grinding disc. This makes it difficult to position the valve correctly, and errors are easily generated during grinding, resulting in the end face of the high-pressure main steam valve tilting and rendering it unusable.

[0004] CN202388353U discloses a tool for cleaning oxide scale from the high-pressure main steam valve of a steam turbine unit, including a grinding rod, an extension rod, and a handle. One end of the extension rod is connected to the top of the grinding rod, and the handle is located at the other end of the extension rod. This tool can conveniently clean the oxide scale generated on the high-pressure main steam valve due to high-temperature and high-pressure operation, ensuring the reliable operation of the high-pressure main steam valve. However, this tool has problems with grinding accuracy and uniformity. Summary of the Invention

[0005] The first aspect of the present invention provides a grinding and repair device for the sealing surface of a high-pressure main steam valve. The grinding and repair device includes a grinding frame, a grinding tool, a force-applying seat, and a fixing component. The grinding and repair device is fixed inside the valve body of the high-pressure main steam valve. The fixing component is fixed to the positioning plate by fastening bolts and threaded bottom holes. The grinding tool is inserted into the grinding tool and fastened by the force-applying seat.

[0006] The high-pressure main steam valve also includes a positioning plate, a valve seat, a sealing surface, and a positioning stop.

[0007] The grinding frame includes a bushing, which is fixedly connected to the positioning plate via a positioning stop.

[0008] The abrasive tool includes self-adhesive sandpaper, a spindle, and a copper sleeve. The self-adhesive sandpaper is bonded to the surface of the copper sleeve, and the copper sleeve is welded to one end of the spindle.

[0009] The force-applying seat includes a force-applying nut, and the grinding wheel is inserted into the grinding wheel and tightened by the force-applying nut of the force-applying seat.

[0010] The other end of the spindle of the grinding tool is fixed in the bushing of the grinding tool.

[0011] A second aspect of the present invention provides a grinding and repair process for the sealing surface of a high-pressure main steam valve, comprising the following steps:

[0012] Step 1: Clean the positioning plate of the high-pressure main steam valve to ensure that its surface is smooth, clean and free of burrs;

[0013] Step 2: Insert the spindle of the grinding wheel into the bushing of the grinding frame and fix it with the force-applying seat. Manually tighten the force-applying nut to keep the compression spring from being stressed, and obtain the assembly.

[0014] Step 3: Apply red lead powder oil solution to the valve seat of the main steam valve to be ground;

[0015] Step 4: Attach self-adhesive sandpaper to the copper sleeve;

[0016] Step 5: Insert the assembly into the valve body and adjust the position of the positioning plate to ensure it is fully inserted;

[0017] Step 6: Install the four fastening bolts of the fasteners into the threaded bottom holes respectively;

[0018] Step 7: Tighten the tension nut to compress the spring;

[0019] Step 8: Control the rotation speed. Use a torque wrench to rotate the spindle of the mold clockwise 2-4 times to obtain the desired result.

[0020] The four fasteners are arranged in an orthogonal, opposite-side configuration.

[0021] Preferably, the four fasteners are arranged horizontally orthogonally at 45°.

[0022] The applicant's research found that a mesh size of 80-300 mesh for the self-adhesive abrasive can improve its bonding performance and prevent it from slipping off during use. In particular, when the mesh size of the self-adhesive abrasive is 240 mesh and the compression rate of the spring is 40-60%, it can effectively improve the smoothness and uniformity of the sealing surface. This is likely because the specific compression rate maintains appropriate pressure between the self-adhesive abrasive and the sealing surface, allowing the abrasive particles of the self-adhesive abrasive to better repair the sealing surface. However, as friction continues, the thickness of the sealing surface decreases, and the compression rate of the spring gradually increases, which can easily lead to the phenomenon of broken lines on the sealing surface. Further research found that controlling the rotation speed of the first rotation to 10 seconds / revolution, the second rotation to 12 seconds / revolution, and the third rotation to 15 seconds / revolution can effectively solve the problem of broken lines on the sealing surface and improve the smoothness of grinding. This is likely because by continuously increasing the rotation speed, the torque can be stably maintained at 200-400 N·m.

[0023] The mesh size of the self-adhesive sandpaper is 80-300 mesh.

[0024] Preferably, the mesh size of the self-adhesive sandpaper is 80-240 mesh.

[0025] More preferably, the self-adhesive sandpaper has a mesh size of 240.

[0026] The compression rate of the compression spring is 40-60%.

[0027] Preferably, the compression rate of the compression spring is 40-50%.

[0028] More preferably, the compression rate of the compression spring is 45%.

[0029] Preferably, the spindle of the grinding tool is rotated clockwise by 3 revolutions using a torque wrench.

[0030] The rotation speed is 10-15 seconds per revolution.

[0031] Preferably, the rotation speed of the first rotation is 10 seconds per rotation, the rotation speed of the second rotation is 12 seconds per rotation, and the rotation speed of the third rotation is 15 seconds per rotation.

[0032] Beneficial effects

[0033] 1. The mesh size of the self-adhesive sandpaper is 80-300 mesh, which can improve the adhesion performance of the self-adhesive sandpaper and prevent it from slipping off during use.

[0034] 2. The self-adhesive sandpaper has a mesh size of 240 and the compression rate of the compression spring is 40-60%, which can effectively improve the smoothness and uniformity of the sealing surface.

[0035] 3. Controlling the rotation speed to 10 seconds / revolution for the first revolution, 12 seconds / revolution for the second revolution, and 15 seconds / revolution for the third revolution can effectively solve the problem of broken lines on the sealing surface and improve the smoothness of grinding. Attached Figure Description

[0036] Figure 1 The front view of the structure of the grinding and repair device in Example 1 is fixed in the high-pressure main steam valve.

[0037] Figure 2 This is a three-dimensional view of the grinding frame structure in Example 1.

[0038] Figure 3 This is a three-dimensional structural view of the mold in Example 1.

[0039] Figure 4 This is a front view of the structure before the force-applying seat and grinding frame are combined in Example 1.

[0040] Figure 5 This is a perspective view of the structure of the force-applying seat and grinding frame before the composite structure of Example 1.

[0041] Figure 6 This is a perspective view of the composite structure of the force-applying seat, grinding frame, and grinding tool in Example 1.

[0042] Figure 7 This is a perspective view of the fastener structure in Example 1.

[0043] The components are as follows: 1. Grinding frame; 2. Grinding tool; 3. Force-applying seat; 4. Fixing component; 5. Positioning plate; 6. Valve body; 7. Valve seat; 8. Sealing surface; 9. Positioning stop; 101. Bushing; 201. Self-adhesive sandpaper; 202. Spindle; 203. Copper sleeve; 301. Force-applying nut; 302. Compression spring; 303. Pressure seat; 401. Fastening bolt; 402. Threaded bottom hole. Detailed Implementation

[0044] Example 1

[0045] A high-pressure main steam valve sealing surface grinding and repair device, such as Figure 1 As shown, the grinding and repair device consists of a grinding frame 1, a grinding tool 2, a force-applying seat 3, and a fixing component 4; the grinding and repair device is fixed inside the valve body 6 of the high-pressure main steam valve; the grinding tool 2 is inserted into the grinding tool 1 and is fastened by the force-applying seat 3; the high-pressure main steam valve also consists of a positioning plate 5, a valve seat 7, a sealing surface 8, and a positioning stop 9.

[0046] like Figure 7 As shown, the fixing member 4 is fixed to the positioning plate 5 by fastening bolts 401 and threaded bottom holes 402;

[0047] like Figure 2As shown, the grinding frame 1 includes a bushing 101, which is fixedly connected to the positioning plate 5 through a positioning stop 9.

[0048] like Figure 3 As shown, the abrasive 2 includes a self-adhesive sandpaper 201, a spindle 202, and a copper sleeve 203. The self-adhesive sandpaper 201 is bonded to the surface of the copper sleeve 203, and the copper sleeve 203 is welded to one end of the spindle 202.

[0049] like Figure 4 and Figure 5 As shown, the force-applying seat 3 is a force-applying nut 301, and the grinding mold 2 is inserted into the grinding mold 1 and is tightened by the force-applying nut 301 of the force-applying seat 3.

[0050] The other end of the spindle 202 of the abrasive 2 is fixed in the bushing 102 of the abrasive 1.

[0051] A grinding and repair process for the sealing surface of a high-pressure main steam valve includes the following steps:

[0052] Step 1: Clean the positioning plate 5 of the high-pressure main steam valve to ensure that its surface is smooth, clean and free of burrs;

[0053] Step 2: Insert the spindle 202 of the grinding wheel 2 into the bushing 101 of the grinding frame 1 and fix it with the force-adjusting seat 3. Manually tighten the force-adjusting nut 301 to keep the compression spring 302 (16*60TF16mm) under no force (compression rate 0%). Figure 6 As shown, the assembled parts are obtained;

[0054] Step 3: Apply a 4mm section of red lead powder oil solution (Shaanxi Huamao Chemical Raw Materials Co., Ltd.) to each of the valve lines 3, 6, 9, and 12 on the valve seat 7 of the main steam valve to be ground;

[0055] Step 4: Attach self-adhesive sandpaper 201 to the copper sleeve 203;

[0056] Step 5: Insert the assembly into the valve housing 6 and adjust the position of the positioning plate 5 so that it is fully inserted;

[0057] Step 6: Install the four fastening bolts 401 of the four fasteners 4 into the threaded bottom holes 402 respectively, with a torque of 200 N·m;

[0058] Step 7: Tighten the tension nut 301 to compress the spring 302;

[0059] Step 8: Control the rotation speed. Use a torque wrench to rotate the spindle 203 of the mold 2 clockwise 3 times to obtain the desired result.

[0060] The four fasteners 4 are arranged horizontally orthogonally at 45°.

[0061] The self-adhesive sandpaper 201 has a mesh count of 240, brand: Norton, model P240.

[0062] The compression rate of the compression spring 302 is 45%.

[0063] The rotation speed for the first revolution is 10 seconds per revolution, the rotation speed for the second revolution is 12 seconds per revolution, and the rotation speed for the third revolution is 15 seconds per revolution.

[0064] Comparative Example 1

[0065] The specific implementation method is the same as in Example 1; the difference is that in Comparative Example 1, the self-adhesive sandpaper 201 has a mesh count of 360, brand: Norton, model P360.

[0066] Comparative Example 2

[0067] The specific implementation method is the same as in Example 1; the difference is that in Comparative Example 2, the compression rate of the compression spring 302 is 30%.

[0068] Comparative Example 3

[0069] The specific implementation method is the same as in Example 1; the difference is that in Comparative Example 3, the rotation speed is 12 seconds / revolution.

[0070] Comparative Example 4

[0071] The specific implementation method is the same as in Example 1; the difference is that in Comparative Example 4, the compression rate of the compression spring 302 is 55%, the rotation speed of the first rotation is 16 seconds / rotation, the rotation speed of the second rotation is 13 seconds / rotation, and the rotation speed of the third rotation is 12 seconds / rotation.

[0072] Performance testing methods

[0073] The performance of the main steam valve sealing surfaces obtained after grinding in the examples and comparative examples was tested, and the test results are listed in Table 1.

[0074] 1. Grinding smoothness: Observe whether the self-adhesive abrasive will slip off during the grinding process. If it does not slip off, it is qualified; otherwise, it is unqualified.

[0075] 2. Sealing performance: Refer to DL / T748.3-2001 standard, the maintenance guide for boiler units of thermal power plants, Part 3: valve and steam-water system maintenance section. "-" means that grinding could not be completed normally and the sealing line test was not performed.

[0076] Performance test data

[0077] Table 1

[0078]

[0079]

Claims

1. A grinding and repair device for the sealing surface of a high-pressure main steam valve, characterized in that, The grinding and repair device includes a grinding frame (1), a grinding tool (2), a force-applying seat (3), and a fixing component (4); the grinding and repair device is fixed inside the valve body (6) of the high-pressure main steam valve; the fixing component (4) is fixed to the positioning plate (5) by fastening bolts (401) and threaded bottom holes (402); the grinding tool (2) is inserted into the grinding frame (1) and fastened by the force-applying seat (3); the high-pressure main steam valve also includes a positioning plate (5), a valve seat (7), a sealing surface (8), and a positioning stop (9); the grinding frame (1) includes a bushing (101). The grinding wheel (2) is fixedly connected to the positioning plate (5) through the positioning stop (9); the grinding wheel (2) includes self-adhesive sandpaper (201), spindle (202), and copper sleeve (203). The self-adhesive sandpaper (201) is bonded to the surface of the copper sleeve (203), and the copper sleeve (203) is welded to one end of the spindle (202); the force-applying seat (3) includes a force-applying nut (301), which is used for fastening; the other end of the spindle (202) of the grinding wheel (2) is fixed in the bushing (102) of the grinding frame (1); The process of grinding and repairing the sealing surface of the high-pressure main steam valve using the aforementioned device includes the following steps: Step 1: Clean the positioning plate (5) of the high-pressure main steam valve to ensure that its surface is smooth, clean and free of burrs; Step 2: Insert the spindle (202) of the grinding tool (2) into the bushing (101) of the grinding frame (1) and fix it with the force-adjusting seat (3). Manually tighten the force-adjusting nut (301) to keep the compression spring (302) from being stressed, and obtain the assembly. Step 3: Apply red lead powder oil solution to the valve seat (7) of the main steam valve to be ground; Step 4: Attach self-adhesive sandpaper (201) to the copper sleeve (203); Step 5: Insert the assembly into the valve housing (6) and adjust the position of the positioning plate (5) so that it is fully inserted; Step 6: Install the fastening bolts (401) of the four fasteners (4) into the threaded bottom holes (402) respectively; Step 7: Tighten the force-applying nut (301) to compress the spring (302); Step 8: Control the rotation speed. Use a torque wrench to rotate the spindle (203) of the mold (2) clockwise 2-4 times to obtain the desired result. The four fasteners are arranged horizontally orthogonally at 45°. The self-adhesive sandpaper (201) has a mesh size of 80-300. The compression rate of the compression spring (302) is 40-60%; The rotation speed is 10-15 seconds per revolution; the first revolution is 10 seconds per revolution, the second revolution is 12 seconds per revolution, and the third revolution is 15 seconds per revolution.

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