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

Abstract

The utility model 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 portion of the bearing seat is matched with the bearing cover to limit axial displacement of the valve rod nut, the upper end of the stand column penetrates through the lower end of the bearing seat 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 a sealing face is effectively protected.

Description

TECHNICAL FIELD

[0001] The utility model belongs to valve technical field, and specifically relates to a sleeve anti-erosion stop valve of pressure self-tight sealing. BACKGROUND

[0002] The stop valve for the drain system of a thermal power unit has a large pressure difference before and after the valve, the medium is mainly two-phase steam and water and has impurities, and the pressure change after throttling in the valve can make the water vaporize to cause flash evaporation, cavitation and other phenomena. Among them, the flash evaporation phenomenon: part of the water vaporizes due to the sudden pressure drop; the cavitation phenomenon: in the low-pressure area, the bubble explosion impacts the inner wall of the valve and the valve core, causing serious material damage. The above phenomena cause serious erosion to the valve core and other internal parts, especially the sealing surface, and shorten the service life of the valve.

[0003] Taking the drain system of a certain 300MW thermal power unit as an example:

[0004] The original system uses a common stop valve, the working pressure is about 23MPa, and the temperature is about 250℃. After the valve runs for 6 months, the valve core sealing surface is seriously worn, which causes a large increase in the valve leakage. The large pressure difference causes flash evaporation, accompanied by cavitation, which damages the valve core and the sealing surface; the solid impurities further aggravate the erosion. SUMMARY

[0005] The utility model discloses a sleeve anti-erosion stop valve of pressure self-tight sealing to solve the above-mentioned technical background.

[0006] The utility model discloses the technical scheme is: a sleeve anti-erosion stop valve of pressure self-tight sealing, including the valve body and its inside valve core, the valve core outer diameter and throttling sleeve inner hole cooperation form the up and down movement of valve core along the axial direction, throttling sleeve circle is equipped with throttling passage, throttling sleeve connects the valve cover, the upper outer circle of valve cover is fixed cover plate, the cover plate is connected with the valve body, the upper portion of valve core is connected with the lower portion of valve rod limit, the middle portion of valve rod light pole part passes through the valve cover, the upper portion of valve rod is combined with valve rod nut, the shaft shoulder part of valve rod nut places the needle bearing for supporting valve rod nut, the needle bearing is arranged in the inside of bearing seat, the upper portion of bearing seat is combined with bearing cover and is limited the axial displacement of valve rod nut, the upper end of stand column passes through the lower end of bearing seat and is fastened, the lower end of stand column is fixed with cover plate.

[0007] More preferably, the throttling passage is in the form of a circular hole, a tapered window or a combination of the two.

[0008] In the technical solution, the combination of the circular hole and the tapered window can provide more flexible and accurate channel combination to adapt to the medium flow in different states; the tapered window can be applied to the working condition with large flow and many impurities in the medium, and the circular hole is suitable for the working condition with large pressure difference and gaseous medium; the combination of various channel forms can help to optimize the fluid flow path, reduce flow resistance and turbulence, throttle and reduce noise, and improve system efficiency.

[0009] Preferably, a packing seat ring is arranged between the middle light rod part of the valve stem and the valve cover, and a lower layer of packing, a graphite ring and an upper layer of packing are sequentially arranged in the gap between the valve stem and the valve cover from bottom to top above the packing seat ring.

[0010] In the technical solution, the multi-layer sealing structure (packing, graphite ring, etc.) effectively prevents medium leakage and ensures the safe operation of the valve under high pressure or corrosive medium; the graphite ring has good wear resistance and self-lubricating performance, reducing the friction between the valve stem and the sealing element and prolonging the service life of the sealing element and the valve stem; the multi-layer sealing design makes the replacement and maintenance of the sealing element more convenient, improving the maintenance efficiency.

[0011] Preferably, a plurality of light holes are machined on the outer circle of the cover plate, the lower end of the second double-headed stud passes through two symmetrical light holes and is screwed with the threaded hole at the upper end of the valve body, the upper end of the second double-headed stud passes through the packing compression plate to compress the packing compression plate, thereby compressing the packing and the graphite ring to ensure the sealing of the valve stem, and the other light holes are connected with the valve body and the cover plate by the first double-headed stud.

[0012] In the technical solution, the double-headed stud is used to compress the packing and the graphite ring, enhancing the sealing effect and preventing medium leakage; the symmetrical installation of the studs distributes the stress evenly, avoiding local stress concentration and improving the stability and reliability of the overall structure.

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

[0014] In the technical solution, the installation of the clamping plate 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 part of the stand is sleeved with the clamping plate to prevent rotation.

[0016] In the technical solution, the sleeving design of the stand and the clamping plate provides additional fixing force, further preventing the rotation of the valve stem and ensuring the stability of the valve during long-term operation; the sleeving structure increases the strength of the connection part, improving the durability and impact resistance of the overall structure.

[0017] More preferably, the clamping plate comprises two pieces, the two clamping plates surround the valve stem, and the two clamping plates are fixedly connected by a hexagonal head bolt, a quarter gap is formed on each side of the clamping plate, and the quarter gaps of the two clamping plates form a half-moon gap for cooperation with the middle part of the stand.

[0018] In the above technical solution, the cooperation of the half-moon gap and the stand ensures the precise positioning of the clamping plate and the stand, and improves the consistency and reliability of the anti-rotation effect; the two clamping plates disperse the stress points, reduce the stress concentration of a single component, and prolong the service life of the clamping plate and the stand.

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

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

[0021] The outer thread of the valve stem is used for transmission, and the torque generated by rotating the hand wheel is converted into an axial force on the valve stem to lift or lower the valve stem, thereby achieving the opening and closing of the valve.

[0022] More preferably, the valve body is provided with a valve body sealing surface, the valve core is provided with a valve core sealing surface cooperating with the valve body sealing surface, and the valve body sealing surface and the valve core sealing surface are both welded with hard alloy and processed to form a sealing pair, which is the key to the sealing of the valve.

[0023] In the above technical solution, the hard alloy material has extremely high hardness and wear resistance, prolonging the service life of the sealing surface and reducing wear; the high strength and good processability of the hard alloy ensure that the sealing surface is smooth and flat, providing reliable sealing effect and preventing medium leakage; the hard alloy material has good corrosion resistance to various media and is suitable for application in harsh working conditions.

[0024] More preferably, the gland is located on the outer side of the valve cover, the throttling sleeve is tightly attached to the lower end of the valve cover, and the gap between the inner cavity of the valve body and the valve cover has, from bottom to top, a pressure self-tight sealing ring, a gland, and a cover plate. After the valve body is screwed into the first double-headed stud and the corresponding nut is tightened, the pressure self-tight sealing ring seals the inner cavity of the valve body, preventing the leakage of the medium.

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

[0026] More preferably, the lower end of the valve cover is provided with a through hole to balance the internal pressure of the valve and avoid difficulty in opening caused by back pressure.

[0027] The utility model discloses relative to prior art's beneficial effect: the utility model has considered the function of resisting scouring protection sealing surface simultaneously, also can adapt to the high temperature and high pressure working condition of thermal power generating unit, and the throttling passage of throttling sleeve circumference has borne the scouring of medium throttling, effectively protected the sealing surface, and the pressure self-tightening valve cover can effectively cope with the high temperature and high pressure working condition of thermal power generating unit. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is the whole structure schematic diagram of the utility model;

[0029] Figure 2 It is Figure 1 the section view of A-A in middle;

[0030] Figure 3 It is Figure 1 the section view of valve body in middle;

[0031] Figure 4 It is Figure 1 the overhead view of valve body in middle;

[0032] Figure 5 It is Figure 1 the side view of valve body in middle;

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

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

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

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

[0037] Figure 10 It is the structure schematic diagram of throttling sleeve (combination throttling);

[0038] Figure 11 It is the structure schematic diagram of clamping plate;

[0039] Wherein, 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-gland; 8-cover plate; 9-first double-ended stud; 10-nut; 11-clamp plate (11.1-quarter notch); 12-hexagonal head bolt; 13-nut; 14-bearing seat; 15-needle roller bearing; 16-valve stem nut; 17-bearing cover; 18-handwheel; 19-locking nut; 20-nut; 21-column; 22-packing pressure plate; 23-packing pressure sleeve; 24-internal hexagonal head screw; 25-graphite ring; 26-packing; 27-packing seat ring; 28-second double-ended stud; 29-nut; 30-washer. Detailed Implementation

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

[0041] like Figures 1-5 As shown, this utility model includes a valve body 1 and a valve core 2 inside it. The outer diameter of the valve core 2 cooperates with the inner hole of the throttling sleeve 3 to form an axial up-and-down movement of the valve core 2. A throttling channel is opened around the circumference of the throttling sleeve 3. The throttling sleeve 3 is connected to the valve cover 5. A cover plate 8 is fixed around the upper outer circumference of the valve cover 5. The cover plate 8 is provided with a smooth hole and is connected to the valve body 1 by threads. The upper part of the valve core 2 is limited to the lower part of the valve stem 4. The smooth rod part in the middle 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. (Thread) The valve stem nut 16 is screwed together, and a needle roller bearing 15 is placed on the shoulder of the valve stem nut 16 to support the valve stem nut 16, reduce the coefficient of friction, and reduce the operating torque. The needle roller bearing 15 is set inside the bearing housing 14. The upper part of the bearing housing 14 is machined with internal threads and the external threads of the bearing cover 17 to restrict the axial displacement of the valve stem nut 16. The lower end of the bearing housing 14 is machined with a smooth hole. The upper end of the column 21 passes through the smooth hole at the lower end of the bearing housing 14 and is fastened with a nut 20. The lower end of the column 21 mates with the stepped hole on the cover plate 8 and is fixed by an internal hexagonal head screw 24.

[0042] In some alternative embodiments, such as Figures 8-10 As shown, the throttling sleeve 3 has an installation step 3.1 on one side, and the throttling channel is in the form of a round hole 3.2, a conical window 3.3, or a combination of both.

[0043] In some optional embodiments, a packing seat ring 27 is provided between the middle smooth part of the valve stem 4 and the valve cover 5. A lower packing 26, a graphite ring 25 and an upper packing 26 are arranged 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 arranged in sequence above the upper packing 26.

[0044] In some alternative embodiments, combined with Figure 7 As shown, the outer ring of the cover plate 8 is machined with multiple smooth holes and stepped holes. The lower end of the second double-ended stud 28 passes through two of the symmetrical smooth holes and screws into the threaded hole at the upper end of the valve body 1. The upper end of the second double-ended stud 28 passes through the packing pressure plate 22. By tightening the nut 29 and the washer 30, the packing pressure plate 22 is tightened, thereby pressing the packing 26 and the graphite ring 25 to ensure the sealing of the valve stem 4. The other smooth holes are screwed into the threaded holes evenly distributed at a 45-degree angle to the upper end of the valve body 1 by the first double-ended stud 9. Together with the nut 10, they connect the valve body 1 and the cover plate 8.

[0045] In some alternative embodiments, the lower part of the external thread of the valve stem 4 is milled into a flat square for mounting the clamping plate 11 to prevent the valve stem 4 from rotating. The middle part of the column 21 fits into the clamping plate 11 to prevent rotation.

[0046] In some alternative embodiments, such as Figure 11 As shown, the clamping plate 11 includes two pieces, which surround the valve stem 4. The two clamping plates 11 are fixedly connected by hexagonal head bolts 12 and nuts 13. A quarter notch 11.1 is opened on both sides of the clamping plate 11. The quarter notches 11.1 of the two clamping plates 11 form a crescent 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. The external thread of the valve stem 4 is used for transmission, converting the torque generated by the rotation of the handwheel 18 into an axial force on the valve stem 4 to raise or lower the valve stem 4, thereby realizing 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 to fix the handwheel.

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

[0049] In some alternative embodiments, the gland 7 is located outside the valve cover 5, the throttling sleeve 3 is tightly attached to 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 has, from bottom to top, the pressure self-tight sealing ring 6, the gland 7, and the cover plate 8 in sequence, the valve body 1 is screwed into the first double-headed stud 9, and after the corresponding nut is tightened, the pressure self-tight sealing ring 6 realizes the sealing of the inner cavity of the valve body 1, thereby avoiding the external leakage of the medium.

[0050] The working principle of the utility model is as follows:

[0051] 1. Initial state: valve is closed

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

[0053] 2. Open the valve

[0054] Operation of hand wheel 18: the operator rotates the hand wheel. The hand wheel is connected with the valve stem 4 through the valve stem nut 16 and the outer thread, and the rotation of the hand wheel converts the rotation torque into the axial force of the valve stem 4 through the thread transmission structure. Axial movement of 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 passes through the sealing structures such as the packing seat ring 27, the packing 26 and the graphite ring 25 to ensure that the medium does not leak during the movement. Movement of valve core 2: the upper part of the valve stem 4 is connected with the lower part of the valve core 2, and with the upward movement of the valve stem 4, the valve core moves axially along the inner hole of the throttling sleeve 3, and gradually opens the throttling passage (circular hole, tapered window or combination of the two). The opening of the throttling passage allows the fluid to pass through the valve, adjusts the pressure change and reduces the noise. The circular hole is suitable for the working condition with large pressure difference, and the medium is mostly gaseous. The tapered window is suitable for the medium with more impurities. Sealing and supporting: at the upper part of the valve stem, the valve stem nut is supported in the bearing seat through the needle bearing 15, so as to ensure that the valve stem is stable and smooth during the axial movement. The bearing cover 17 is matched with the bearing seat 14 to limit the axial displacement of the valve stem nut and prevent excessive movement.

[0055] 3. Maintain the open state

[0056] Sealing structure: the packing and the graphite ring are pressed tightly by the second double-headed stud 28, so as to ensure the sealing between the valve stem and the valve cover and prevent the leakage of the medium. Anti-rotation structure: the milling part of the lower part of the outer thread of the valve stem is installed with the clamping plate 11 to prevent the valve stem from rotating accidentally during the operation. The sleeve design of the stand column 21 and the clamping plate 11 further enhances the anti-rotation effect, so as to ensure that the position of the valve stem is stable in the open state and is not disturbed by external force.

[0057] 4. Close the valve

[0058] Operation hand wheel reverse rotation: The operator reverses the rotation of the hand wheel, which 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 passage and blocking fluid flow. As the valve core 2 moves downward, the inner hole of the throttling sleeve 3 cooperates with the outer diameter of the valve core 2, and by rotating the hand wheel, an axial force is applied to seal it, and the packing gland and packing plate continue to compress the packing and graphite ring, ensuring that the seal between the valve stem and the valve cover is not affected.

[0059] Seal pair: The sealing surface of the valve body 1 and the valve core 2 is welded with hard alloy to provide high wear resistance and reliable sealing performance, ensuring that the seal pair is tightly combined during opening and closing to prevent medium leakage. Pressure self-tightening seal ring: The pressure self-tightening seal ring 6 between the valve cover 5 and the gland 7 automatically adjusts the sealing tightness according to the medium pressure, further preventing leakage of the medium at the connection between the valve cover and the gland, ensuring overall sealing.

[0060] Bearing and hand wheel fixation: The bearing cover is fixed to the outer ring of the valve stem nut, and the hand wheel is fixed above the bearing cover, ensuring stable transmission structure and reducing valve stem shaking or displacement during operation. Locking nut:

[0061] The locking nut above the hand wheel prevents the hand wheel from loosening during operation, ensuring stable transmission of the axial force of the valve stem and improving the reliability and safety of the operation.

[0062] Convenient maintenance: The multi-layer sealing structure (packing, graphite ring, etc.) and double-headed stud design make it easier to replace and maintain the seal. The clamping plate 11 is fixed by hexagonal head bolts 12, making it easy to quickly disassemble and install when needed, reducing maintenance time and cost.

[0063] Integrated workflow:

[0064] Opening: Operate the hand wheel, which pushes the valve stem upward through threaded transmission, and the valve core moves along the throttling sleeve to open the throttling passage and allow fluid to pass.

[0065] Maintain open: The sealing structure and anti-rotation design ensure stable valve stem position, reliable sealing, and prevent medium leakage.

[0066] Closing: Reverse operation of the hand wheel, pushing the valve stem downward, the valve core moves to the closed position, blocking fluid flow and restoring the sealing state.

[0067] Sealing and stability: Hard alloy sealing surface and pressure self-tightening seal ring ensure sealing effect, and bearings and locking devices provide operational stability and safety.

[0068] Through the cooperation of the above-mentioned components, the valve realizes accurate flow control, reliable sealing performance and stable operation process, and ensures efficient and safe operation under various working conditions.

[0069] What is not described in detail in the specification is the prior art known to those skilled in the art.

Claims

1. A pressure self-tightening sleeve erosion check valve comprising a valve body (1) and a valve core (2) inside it, characterized in that: The outer diameter of the valve core (2) is matched with the inner hole of the throttling sleeve (3) to form the up and down movement of the valve core (2) along the axial direction, the throttling sleeve (3) is connected with the valve cover (5), the outer side of the upper part of the valve cover (5) is fixed with the cover plate (8), the cover plate (8) is connected with the valve body (1), the upper part of the valve core (2) is limitedly connected with the lower part of the valve stem (4), the middle light rod part of the valve stem (4) passes through the valve cover (5), the upper part of the valve stem (4) is screwed with the valve stem nut (16), the shaft shoulder part of the valve stem nut (16) is placed with the needle bearing (15) for supporting the valve stem nut (16), the needle bearing (15) is arranged in the bearing seat (14), the upper part of the bearing seat (14) is matched 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 seat (14) and is fastened, and the lower end of the column (21) is fixed with the cover plate (8).

2. A pressure self-sealing sleeve scouring check valve according to claim 1, characterized in that: The throttling passage is in the form of a circular hole (3.2), a tapered window (3.3) or a combination of the two.

3. A pressure self-sealing sleeve scouring check valve according to claim 1, wherein: The middle light rod part of the valve stem (4) is provided with a packing seat ring (27) between the valve cover (5), the gap between the valve stem (4) above the packing seat ring (27) and the valve cover (5) is sequentially provided from bottom to top with a lower layer of packing (26), a graphite ring (25) and an upper layer of packing (26), and the upper layer of packing (26) is sequentially provided with a packing pressing sleeve (23) and a packing pressing plate (22).

4. A pressure self-sealing sleeve scouring check valve according to claim 3, wherein: A plurality of light holes are machined on the outer circle of the cover plate (8), the lower end of the second double-headed stud (28) is screwed with the threaded hole of the upper end of the valve body (1) through two symmetrical light holes, the upper end of the second double-headed stud (28) passes through the packing pressing plate (22) to tension the packing pressing plate (22), and the other light holes are connected with the valve body (1) and the cover plate (8) by the first double-headed stud (9).

5. A pressure self-sealing sleeve scouring check valve according to claim 1, wherein: The outer thread lower part of the valve stem (4) is milled into a flat square for installing the clamping plate (11) to prevent the valve stem (4) from rotating.

6. A pressure self-sealing sleeve scouring check valve according to claim 5, wherein: The middle part of the column (21) is sleeved with the clamping plate (11) for anti-rotation.

7. A pressure self-sealing sleeve scouring check valve according to claim 6, wherein: The clamping plate (11) includes two pieces, the valve stem (4) is surrounded by the two clamping plates (11), the two clamping plates (11) are fixedly connected by the hexagonal head bolt (12), a quarter notch (11.1) is formed on each side of the clamping plate (11), and the quarter notches (11.1) of the two clamping plates (11) constitute a half-moon notch for matching with the middle part of the column (21).

8. A pressure self-sealing sleeve scouring check valve according to claim 1, wherein: The bearing cover (17) and the hand wheel (18) are fixed to the outer circle of the valve stem nut (16), the bearing cover (17) is located below the hand wheel (18), and the outer thread of the valve stem (4) above the hand wheel (18) is provided with a locking nut (19).

9. A pressure self-sealing sleeve scouring check valve according to claim 1, wherein: The valve body (1) is provided with a valve body sealing surface (1.1), the valve core (2) is provided with a valve core sealing surface (2.1) matched with the valve body sealing surface (1.1), and the valve body sealing surface (1.1) and the valve core sealing surface (2.1) are both welded with hard alloy.

10. A pressure self-sealing sleeve scouring check valve according to claim 4, wherein: The gland (7) is located outside the valve cover (5) periphery, the throttle sleeve (3) and the valve cover (5) lower end closely, the gap between the valve body (1) inner cavity and the valve cover (5) has pressure self-tight sealing ring (6), gland (7), cover plate (8) from bottom to top in turn, the valve body (1) is screwed into the first double head stud (9), after screwing the corresponding nut, the pressure self-tight sealing ring (6) realizes the cavity sealing of the valve body (1).

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