Sleeve anti-scouring stop valve with pressure self-tightening sealing function

Abstract

The invention discloses a pressure self-tightening sealing sleeve anti-scouring stop valve. The check valve comprises a valve body and a valve element in the valve body, the outer diameter of the valve element is matched with an inner hole of a throttling sleeve to enable the valve element to move up and down in the axial direction, a throttling channel is formed in the periphery of the throttling sleeve, the throttling sleeve is connected with a valve deck, and a cover plate is fixed to the periphery of the outer side of the upper portion of the valve deck and connected with the valve body. The upper portion of the valve element is connected with the lower portion of the valve rod in a limiting mode, a polished rod portion in the middle of the valve rod penetrates through the valve cover, the upper portion of the valve rod is screwed with the valve rod nut, and the needle bearing is placed on a shaft shoulder portion of the valve rod nut and used for supporting the valve rod nut. The upper end of the stand column penetrates through the lower end of the bearing cover to be fastened, and the lower end of the stand column is fixed to the cover plate. The throttling channel on the circumference of the throttling sleeve bears scouring generated by medium throttling, and the sealing face is effectively protected.

Description

Technical Field

[0001] The invention belongs to the technical field of valves, and in particular relates to a sleeve anti-scour stop valve with pressure self-tight sealing. Background Art

[0002] The cut-off valve used in the drainage system of thermal power units has a large pressure difference before and after the valve. The medium is mostly steam and water with impurities. The pressure change after throttling inside the valve will vaporize the water, resulting in flash evaporation, cavitation and other phenomena. Among them, the flash evaporation phenomenon: liquid water vaporizes part of the water due to a sudden drop in pressure; cavitation phenomenon: in the low-pressure area, the bubble bursts and impacts the inner wall and valve core of the valve, causing serious material damage. The above phenomenon causes serious erosion of the valve core and other internal parts, especially the sealing surface, shortening the service life of the valve.

[0003] Take the drainage system of a 300MW thermal power unit as an example:

[0004] The original system used ordinary stop valves with a working pressure of about 23MPa and a temperature of about 250℃. After the valve was in operation for 6 months, the valve core sealing surface was seriously worn, resulting in a significant increase in valve leakage. The excessive pressure difference caused flash evaporation, accompanied by cavitation, which damaged the valve core and sealing surface; solid impurities further aggravated the erosion. Summary of the invention

[0005] The purpose of the present invention is to solve the deficiencies of the above-mentioned background technology and to provide a sleeve anti-scour stop valve with a pressure self-tight seal.

[0006] The technical solution adopted in the present invention is: a pressure-self-tightening and sealing sleeve anti-scour stop valve, including a valve body and a valve core therein, the outer diameter of the valve core cooperates with the inner hole of the throttling sleeve to form the axial up and down movement of the valve core, a throttling channel is arranged around the throttling sleeve, the throttling sleeve is connected to the valve cover, the cover plate is fixed around the outer periphery of the upper part of the valve cover, the cover plate is connected to the valve body, the upper part of the valve core is limitedly connected to the lower part of the valve stem, the middle part of the valve stem passes through the valve cover, the upper part of the valve stem is screwed with the valve stem nut, a needle bearing is placed on the shoulder of the valve stem nut to support the valve stem nut, the needle bearing is arranged inside the bearing seat, the upper part of the bearing seat cooperates with the bearing cover to limit the axial displacement of the valve stem nut, the upper end of the column passes through the lower end of the bearing cover and is fastened, and the lower end of the column is fixed to the cover plate.

[0007] Preferably, the throttling channel is in the form of a circular hole, a conical window or a combination of the two.

[0008] In the above technical solution, the combined design of circular holes and conical windows can provide a more flexible and precise channel combination to adapt to the flow of media under different conditions; the conical window can be suitable for working conditions with large flow rates and more impurities in the medium, while the circular hole is suitable for working conditions with large pressure differences and the medium is mostly gaseous; the combination of multiple channel forms helps to optimize the fluid flow path, reduce flow resistance and turbulence, throttle and reduce noise, and improve system efficiency.

[0009] More preferably, a packing seat ring is provided between the middle smooth rod portion of the valve stem and the valve cover, and a lower layer of packing, a graphite ring and an upper layer of packing are provided in sequence from bottom to top in the gap between the valve stem and the valve cover above the packing seat ring, and a packing sleeve and a packing pressure plate are provided in sequence above the upper layer of packing.

[0010] In the above technical solution, the multi-layer sealing structure (filler, graphite ring, etc.) effectively prevents medium leakage and ensures the safe operation of the valve under high pressure or corrosive media; the graphite ring has good wear resistance and self-lubricating properties, reduces the friction between the valve stem and the seal, and extends the service life of the seal and the valve stem; the multi-layer sealing design makes the replacement and maintenance of the seal more convenient and improves maintenance efficiency.

[0011] Preferably, a plurality of light holes are processed on the outer ring of the cover plate, the lower end of the second stud passes through two symmetrical light holes and is screwed into the threaded holes on the upper end of the valve body, the upper end of the second stud passes through the packing pressure plate to tighten the packing pressure plate, thereby pressing the packing and the graphite ring to ensure the sealing of the valve stem, and the other light holes are passed through by the first stud to connect the valve body and the cover plate.

[0012] In the above technical solution, the packing and the graphite ring are compressed by double-headed studs to enhance the sealing effect and prevent medium leakage; the symmetrically installed studs distribute the force evenly to avoid local stress concentration and improve the stability and reliability of the overall structure.

[0013] Preferably, the lower portion of the external thread of the valve stem is milled into a flat square for installing a clamping plate to prevent the valve stem from rotating.

[0014] In the above technical solution, the installation of the clamp effectively prevents the valve stem from accidentally rotating due to vibration or external force during operation, ensuring the stability of the valve position; preventing the valve stem from rotating reduces the risk of misoperation and improves the safety and reliability of valve operation.

[0015] Preferably, the middle portion of the column cooperates with a splint sleeve to prevent rotation.

[0016] In the above technical solution, the sleeve design of the column and the clamp provides additional fixing force, further preventing the rotation of the valve stem and ensuring the stability of the valve during long-term operation; the sleeve structure increases the strength of the connecting part and improves the durability and impact resistance of the overall structure.

[0017] Preferably, the splints include two pieces, the two splints surround the valve stem, the two splints are fixedly connected by hexagonal bolts, a quarter notch is provided on both sides of the splints respectively, and the quarter notches of the two splints form a half-moon notch for cooperating with the middle part of the column.

[0018] In the above technical solution, the cooperation between the half-moon notch and the column ensures the precise alignment of the splint and the column, improving the consistency and reliability of the anti-rotation effect; the two splints disperse the stress points, reduce stress concentration on a single component, and extend the service life of the splint and the column.

[0019] More preferably, the bearing cover and the handwheel are fixed to the outer ring of the valve stem nut, the bearing cover is located below the handwheel, and a locking nut is provided on the external thread of the valve stem above the handwheel.

[0020] In the above technical solution, the fixing of the bearing cover and the handwheel ensures the stability of the transmission structure and reduces the shaking or displacement of the valve stem during operation.

[0021] The external thread of the valve stem is used for transmission, which converts the torque generated by the rotation of the handwheel into an axial force on the valve stem to lift or lower the valve stem, and finally realize the opening and closing of the valve.

[0022] More preferably, the valve body is provided with a valve body sealing surface, and the valve core is provided with a valve core sealing surface matching the valve body sealing surface. Both the valve body sealing surface and the valve core sealing surface are welded with hard alloy and formed through processing. The two sealing surfaces are combined to form a sealing pair, which becomes the key to the valve sealing.

[0023] In the above technical solution, the cemented carbide material has extremely high hardness and wear resistance, which prolongs the service life of the sealing surface and reduces wear; the high strength and good processing performance of the cemented carbide ensure that the sealing surface is flat and smooth, providing a reliable sealing effect and preventing medium leakage; the cemented carbide material has good corrosion resistance to a variety of media and is suitable for applications in harsh working conditions.

[0024] Preferably, the pressure cover is located on the outer circumference of the valve cover, the throttling sleeve is tightly fitted with the lower end of the valve cover, and the gap between the inner cavity of the valve body and the valve cover is provided with a pressure self-tightening sealing ring, a pressure cover, and a cover plate from bottom to top. The valve body is screwed into the first stud, and after the corresponding nut is tightened, the pressure self-tightening sealing ring realizes the sealing of the middle cavity of the valve body to prevent leakage of the medium.

[0025] In the above technical solution, the pressure self-tightening seal ring can automatically adjust the sealing tightness according to the medium pressure to ensure that a reliable seal can be maintained when the pressure changes. It effectively prevents the medium from leaking from the connection between the valve cover and the gland, and improves the overall sealing performance and safety of the valve. The self-tightening design reduces the leakage problem caused by aging of the seal or pressure fluctuations, and reduces the maintenance frequency and cost.

[0026] Preferably, a through hole is provided at the lower end of the valve cover to balance the internal pressure of the valve and avoid difficulty in opening due to back pressure.

[0027] The beneficial effects of the present invention compared to the prior art are as follows: the present invention not only takes into account the function of resisting scour and protecting the sealing surface, but can also adapt to the high temperature and high pressure working conditions of thermal power units. The throttling channel on the circumference of the throttling sleeve withstands the scour caused by the throttling of the medium, effectively protecting the sealing surface. At the same time, the pressure self-tightening sealing valve cover can effectively cope with the high temperature and high pressure working conditions of the thermal power unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0029] Figure 2 for Figure 1 Sectional view at AA;

[0030] Figure 3 for Figure 1 Sectional view of the valve body;

[0031] Figure 4 for Figure 1 Top view of the middle valve body;

[0032] Figure 5 for Figure 1 Side view of the middle valve body;

[0033] Figure 6 It is a schematic diagram of the valve core structure;

[0034] Figure 7 is a schematic diagram of the cover plate structure;

[0035] Figure 8 It is a schematic diagram of the structure of a throttling sleeve (circular hole throttling);

[0036] Fig. 9 It is a schematic diagram of the structure of the throttling sleeve (conical window throttling);

[0037] Fig.10 It is a schematic diagram of the structure of a throttling sleeve (combined throttling);

[0038] Fig.11 is a schematic diagram of the splint structure;

[0039] Among them, 1-valve body (1.1-valve body sealing surface); 2-valve core (2.1-valve core sealing surface); 3-throttling sleeve (3.1-installation step; 3.2-round hole; 3.3-conical window); 4-valve stem; 5-valve cover; 6-pressure self-tightening sealing ring; 7-pressure cover; 8-cover plate; 9-first stud; 10-nut; 11-clamp plate (11.1-quarter notch); 12-hexagonal head bolt; 13-nut; 14-bearing seat; 15-needle bearing; 16-valve stem nut; 17-bearing cover; 18-handwheel; 19-locking nut; 20-nut; 21-column; 22-packing pressure plate; 23-packing sleeve; 24-hexagon socket head screw; 25-graphite ring; 26-packing; 27-packing seat ring; 28-second stud; 29-nut; 30-washer. DETAILED DESCRIPTION

[0040] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments to facilitate a clear understanding of the present invention, but they do not constitute a limitation on the present invention.

[0041] like Figure 1-5 As shown, the present invention includes a valve body 1 and a valve core 2 inside the valve body 1. The outer diameter of the valve core 2 cooperates with the inner hole of the throttling sleeve 3 to form the valve core 2 to move up and down along the axial direction. The throttling sleeve 3 is provided with a throttling channel around the throttling sleeve 3. The throttling sleeve 3 is connected to the valve cover 5. The outer circumference of the upper part of the valve cover 5 is fixed with a cover plate 8. The cover plate 8 is provided with a light hole and is connected to the valve body 1 through a thread. The upper part of the valve core 2 is limitedly connected with the lower part of the valve stem 4. The middle part of the light rod of the valve stem 4 passes through the valve cover 5. The upper part of the valve stem 4 is provided with an external thread (trapezoidal thread) and an internal thread (trapezoidal thread) of the valve stem nut 16. ) is screwed together, a needle bearing 15 is placed on the shoulder of the valve stem nut 16 to support the valve stem nut 16, reduce the friction coefficient, and reduce the operating torque. The needle bearing 15 is arranged inside the bearing seat 14. The upper part of the bearing seat 14 is processed with an internal thread and the external thread of the bearing cover 17 cooperates to limit the axial displacement of the valve stem nut 16. The lower end of the bearing seat 14 is processed with a light hole. The upper end of the column 21 passes through the light hole at the lower end of the bearing cover 14 and is fastened with a nut 20. The lower end of the column 21 cooperates with the stepped hole on the cover plate 8 and is fixed by a hexagon socket head screw 24.

[0042] In some optional embodiments, such as Figure 8-10 As shown, a mounting step 3.1 is provided on one side of the throttling sleeve 3, and the throttling channel is in the form of a circular hole 3.2, a conical window 3.3 or a combination of the two.

[0043] In some optional embodiments, a packing seat ring 27 is provided between the middle smooth rod portion of the valve stem 4 and the valve cover 5, and in the gap between the valve stem 4 and the valve cover 5 above the packing seat ring 27, a lower layer of packing 26, a graphite ring 25 and an upper layer of packing 26 are provided in sequence from bottom to top, and a packing sleeve 23 and a packing pressure plate 22 are provided in sequence above the upper layer of packing 26.

[0044] In some optional embodiments, combined with Figure 7 As shown, a plurality of light holes and stepped holes are processed on the outer ring of the cover plate 8, the lower end of the second stud 28 passes through two symmetrical light holes and is screwed into the threaded holes on the upper end of the valve body 1, the upper end of the second stud 28 passes through the packing pressure plate 22, and the packing pressure plate 22 is tightened by tightening the nut 29 and the gasket 30, so that the packing 26 and the graphite ring 25 are pressed to ensure the sealing of the valve stem 4, and the other light holes are screwed into the threaded holes uniformly distributed at 45 degrees to the upper end of the valve body 1 by the first stud 9, and the valve body 1 is connected to the cover plate 8 together with the nut 10.

[0045] In some optional embodiments, the lower portion of the external thread of the valve stem 4 is milled to form a flat square for mounting a clamping plate 11 to prevent the valve stem 4 from rotating. The middle portion of the column 21 is sleeved with the clamping plate 11 to prevent rotation.

[0046] In some optional embodiments, such as Fig.11 As shown, the clamping plate 11 includes two pieces, and the two clamping plates 11 surround the valve stem 4. The two clamping plates 11 are fixedly connected by hexagonal bolts 12 and nuts 13. A quarter notch 11.1 is respectively opened on both sides of the clamping plate 11. The quarter notch 11.1 of the two clamping plates 11 forms a half-moon notch for matching with the middle part of the column 21.

[0047] In some optional embodiments, the bearing cover 17 and the handwheel 18 are fixed to the outer ring of the valve stem nut 16, the bearing cover 17 is located below the handwheel 18, and the external thread of the valve stem 4 is used for transmission, which converts the torque generated by the rotation of the handwheel 18 into an axial force on the valve stem 4 so as to lift or lower the valve stem 4, and finally realize the opening and closing of the valve. A locking nut 19 is provided on the external thread of the valve stem 4 above the handwheel 18 for fixing the handwheel.

[0048] In some optional embodiments, the valve body 1 is welded with hard alloy to form the valve body sealing surface 1.1 ( Figure 3 As shown), the valve core 2 is welded with hard alloy to form the valve core sealing surface 2.1 ( Figure 6 As shown in the figure, the two sealing surfaces combine to form a sealing pair, which becomes the key to valve sealing.

[0049] In some optional embodiments, the pressure cap 7 is located on the outer circumference of the valve cover 5, the throttling sleeve 3 is tightly fitted with the lower end of the valve cover 5, and the gap between the inner cavity of the valve body 1 and the valve cover 5 is provided with a pressure self-tightening sealing ring 6, a pressure cap 7, and a cover plate 8 from bottom to top. The valve body 1 is screwed into the first stud 9. After tightening the corresponding nut, the pressure self-tightening sealing ring 6 realizes the sealing of the middle cavity of the valve body 1 to prevent leakage of the medium.

[0050] Working principle of the present invention:

[0051] 1. Initial state: valve closed

[0052] Valve body 1 and valve core 2: Valve core 2 is in the lower position of the inner hole of throttling sleeve 3, blocking the flow of fluid. The outer diameter of valve core 2 is matched with the clearance of the inner hole of throttling sleeve 3. Valve stem 4 and hand wheel 18: Hand wheel 18 is in the initial position, valve stem 4 applies axial force to seal through the rotation of hand wheel 18, and valve core 2 remains in the closed position.

[0053] 2. Open the valve

[0054] Operating hand wheel 18: The operator rotates the hand wheel. The hand wheel is connected to the external thread of the valve stem 4 through the valve stem nut 16. The rotation of the hand wheel converts the rotational torque into an axial force on the valve stem 4 through the threaded transmission structure. Axial movement of the valve stem 4: The axial force pushes the valve stem 4 to move upward. The middle light rod part of the valve stem 4 passes through the valve cover 5, and the sealing structure such as the packing seat ring 27, the packing 26, and the graphite ring 25 ensures that the medium does not leak during the movement. Movement of the valve core 2: The upper part of the valve stem 4 is limitedly connected to the lower part of the valve core 2. As the valve stem 4 moves upward, the valve core moves axially along the inner hole of the throttling sleeve 3, and gradually opens the throttling channel (circular hole, conical window or a combination of the two). The opening of the throttling channel allows the fluid to pass through the valve, adjust the pressure change, and reduce noise. The circular hole is suitable for working conditions with large pressure difference and the medium is mostly gaseous, and the conical window is suitable for media with more impurities. Sealing and support: On the upper part of the valve stem, the valve stem nut is supported in the bearing seat by a needle bearing 15, ensuring that the valve stem is stable and smooth when moving axially. The bearing cap 17 cooperates with the bearing seat 14 to limit the axial displacement of the valve stem nut and prevent excessive movement.

[0055] 3. Keep it open

[0056] Sealing structure: The packing gland and packing plate compress the packing and graphite ring through the second stud 28 to ensure the seal between the valve stem and the valve cover to prevent medium leakage. Anti-rotation structure: The milling part of the lower part of the external thread of the valve stem is installed with a clamping plate 11 to prevent the valve stem from accidentally rotating during operation. The sleeve design of the column 21 and the clamping plate 11 further enhances the anti-rotation effect, ensuring that the valve stem is stable in position when open and is not disturbed by external forces.

[0057] 4. Close the valve

[0058] Reverse rotation of the operating handwheel: The operator rotates the handwheel in the opposite direction, and the handwheel converts the rotational torque into an axial force in the opposite direction through the threaded transmission structure, pushing the valve stem downward. Axial movement of the valve stem 4: The valve stem 4 moves downward, driving the valve core 2 to move axially downward along the inner hole of the throttling sleeve, gradually closing the throttling channel and blocking the flow of fluid. As the valve core 2 moves downward, the inner hole of the throttling sleeve 3 and the outer diameter clearance of the valve core 2 are matched. By turning the handwheel, an axial force is applied to seal, and the packing sleeve and the packing pressure plate continue to keep the packing and the graphite ring pressed tightly to ensure that the seal between the valve stem and the valve cover is not affected.

[0059] Sealing pair: The sealing surface of the valve body 1 and the valve core 2 is formed by welding with hard alloy, which provides high wear resistance and reliable sealing performance, ensuring that the sealing pair is tightly combined during the opening and closing process to prevent medium leakage. Pressure self-tightening sealing ring: The pressure self-tightening sealing ring 6 between the bonnet 5 and the gland 7 axially automatically adjusts the sealing tightness according to the medium pressure, further preventing the medium from leaking at the connection between the bonnet and the gland, and ensuring the overall sealing.

[0060] Bearing and handwheel fixation: The bearing cover is fixed to the outer ring of the valve stem nut, and the handwheel is fixed above the bearing cover to ensure the stability of the transmission structure and reduce the shaking or displacement of the valve stem during operation. Locking nut: The locking nut above the handwheel prevents the handwheel from loosening during operation, ensuring the stable transmission of the axial force of the valve stem and improving the reliability and safety of operation.

[0061] Easy maintenance: The multi-layer sealing structure (filler, graphite ring, etc.) and stud design make seal replacement and maintenance more convenient. The clamping plate 11 is fixed by hexagonal bolts 12, which is convenient for quick disassembly and installation when needed, reducing maintenance time and cost.

[0062] Comprehensive workflow:

[0063] Open: Operate the handwheel, the handwheel pushes the valve stem upward through thread transmission, the valve core moves along the throttling sleeve, opens the throttling channel, and allows the fluid to pass.

[0064] Maintain open: The sealing structure and anti-rotation design ensure the valve stem position is stable, the seal is reliable, and the medium leakage is prevented.

[0065] Close: Reverse the operation of the hand wheel to push the valve stem downward, and the valve core moves to the closed position, blocking the fluid flow and restoring the sealing state.

[0066] Sealing and stability: Carbide sealing surface and pressure self-tightening sealing ring ensure the sealing effect, and the bearing and locking device provide operational stability and safety.

[0067] Through the coordinated work of the above components, the valve achieves precise flow control, reliable sealing performance and stable operation process, ensuring efficient and safe operation under various working conditions.

[0068] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A pressure-tightening sleeve anti-scour stop valve, comprising a valve body (1) and a valve core (2) therein, characterized in that: The outer diameter of the valve core (2) cooperates with the inner hole of the throttling sleeve (3) to form the valve core (2) to move up and down along the axial direction. The throttling sleeve (3) is provided with a throttling channel around its periphery. The throttling sleeve (3) is connected to the valve cover (5). The upper outer periphery of the valve cover (5) is fixed with a cover plate (8). The cover plate (8) is connected to the valve body (1). The upper part of the valve core (2) is limitedly connected to the lower part of the valve stem (4). The middle part of the light rod of the valve stem (4) passes through the valve cover (5). (4) The upper part is screwed with the valve stem nut (16), and a needle bearing (15) is placed on the shoulder of the valve stem nut (16) to support the valve stem nut (16). The needle bearing (15) is arranged inside the bearing seat (14). The upper part of the bearing seat (14) cooperates with the bearing cover (17) to limit the axial displacement of the valve stem nut (16). The upper end of the column (21) passes through the lower end of the bearing cover (14) and is fastened, and the lower end of the column (21) is fixed to the cover plate (8).

2. A pressure-tightening sleeve anti-scour stop valve according to claim 1, characterized in that: The throttling channel is in the form of a circular hole (3.2), a conical window (3.3) or a combination of the two.

3. The pressure-tightening sleeve anti-scour stop valve according to claim 1, characterized in that: A packing seat ring (27) is provided between the middle smooth rod portion of the valve stem (4) and the valve cover (5); a lower packing (26), a graphite ring (25) and an upper packing (26) are provided in sequence from bottom to top in the gap between the valve stem (4) and the valve cover (5) above the packing seat ring (27); a packing sleeve (23) and a packing pressure plate (22) are provided in sequence above the upper packing (26).

4. A sleeve anti-scour stop valve with pressure self-tightening seal according to claim 3, characterized in that: The outer ring of the cover plate (8) is processed with a plurality of light holes, the lower end of the second stud (28) passes through two symmetrical light holes and is screwed into the threaded holes at the upper end of the valve body (1), the upper end of the second stud (28) passes through the packing pressure plate (22) to tighten the packing pressure plate (22), and the other light holes are passed through by the first stud (9) to connect the valve body (1) and the cover plate (8).

5. The pressure-tightening sleeve anti-scour stop valve according to claim 1, characterized in that: The flat square formed by milling the lower portion of the external thread of the valve stem (4) is used for installing a clamping plate (11) to prevent the valve stem (4) from rotating.

6. A sleeve anti-scour stop valve with pressure self-tightening seal according to claim 5, characterized in that: The middle part of the upright post (21) is sleeved with the clamping plate (11) to prevent rotation.

7. A pressure-tightening sleeve anti-scour stop valve according to claim 6, characterized in that: The clamping plate (11) includes two pieces, the two clamping plates (11) surround the valve stem (4), and the two clamping plates (11) are fixedly connected by a hexagonal bolt (12). A quarter notch (11.1) is respectively provided on both sides of the clamping plate (11), and the quarter notches (11.1) of the two clamping plates (11) form a half-moon notch for matching with the middle part of the column (21).

8. The pressure-tightening sleeve anti-scour stop valve according to claim 1, characterized in that: The bearing cover (17) and the hand wheel (18) are fixed to the outer ring of the valve stem nut (16), the bearing cover (17) is located below the hand wheel (18), and a locking nut (19) is provided on the external thread of the valve stem (4) above the hand wheel (18).

9. The pressure-tightening sleeve anti-scour stop valve according to claim 1, characterized in that: The valve body (1) is provided with a valve body sealing surface (1.1), and the valve core (2) is provided with a valve core sealing surface (2.1) matching the valve body sealing surface (1.1), and both the valve body sealing surface (1.1) and the valve core sealing surface (2.1) are welded with hard alloy.

10. A sleeve anti-scour stop valve with pressure self-tight seal according to claim 4, characterized in that: The pressure cover (7) is located on the outer circumference of the valve cover (5), the throttling sleeve (3) is tightly fitted with the lower end of the valve cover (5), and the gap between the inner cavity of the valve body (1) and the valve cover (5) is provided with a pressure self-tightening sealing ring (6), a pressure cover (7), and a cover plate (8) from bottom to top. The valve body (1) is screwed into the first stud (9), and after the corresponding nut is tightened, the pressure self-tightening sealing ring (6) realizes the sealing of the middle cavity of the valve body (1).

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