High-sealing-performance eccentric semi-ball valve and method thereof

Abstract

The invention discloses a high-sealing-performance eccentric semi-ball valve and a method thereof, and belongs to the technical field of valves. The high-sealing-performance eccentric semi-ball valve comprises a valve body and a semi-ball valve element; a valve seat is arranged on one side of a liquid outlet of the valve body, and a spherical crown used for abutting against the valve seat to achieve the sealing effect on the valve body is arranged on the outer edge of the valve body. A multi-stage sealing mechanism used for avoiding leakage at the dynamic sealing position of the upper valve rod is arranged between the upper valve rod and the upper flange. A soft and hard double-sealing mechanism is arranged between the spherical crown and the valve seat; the soft and hard double-sealing mechanism comprises a main sealing ring and a self-cleaning type elastic hard sealing assembly, and a low-torque rotating mechanism capable of effectively reducing the torque of the upper valve rod and the torque of the lower valve rod is arranged between the lower valve rod and the lower flange. By means of the mode, an elastic pair sealing structure between the spherical crown and the valve seat is achieved through cooperation of the spring and the floating type anti-falling pin, sealing is more facilitated, the elastic pre-tightening function of the valve seat is achieved through the spring, the valve seat has the load compensation function all the time, and the reliable sealing condition is met.

Description

Technical Field

[0001] The invention relates to the technical field of valves, and in particular to an eccentric hemispherical valve with high sealing performance and a method thereof. Background Art

[0003] Chinese patent CN215293673U discloses a large-caliber soft-sealed eccentric semi-ball valve, comprising a vertically arranged valve body, a ball in the valve body, a ball crown at the upper end of the ball, a sealing ring on the ball crown, and a valve seat in the upper part of the valve body and matched with the sealing ring, wherein the sealing ring is a circular ring; a circular boss is coaxially arranged in the middle of the upper side of the ball crown, the sealing ring is sleeved on the circular boss and fixed to the ball crown by a plurality of bolts, and the plurality of bolts are evenly distributed around the circular boss; the sealing ring comprises an annular metal skeleton and a rubber lining vulcanized on the outer side of the metal skeleton, the rubber lining is a sealing surface, the metal skeleton is coaxially arranged with the circular boss and a plurality of through holes for the bolts to pass through are arranged on the inner side thereof; the valve seat is an annular metal welding ring welded on the valve body, and the semi-ball valve increases the sealing performance of the valve by adjusting the sealing ring and the valve seat, but the eccentric semi-ball valve still has the following problems:

[0004] 1. River water and lake water usually contain a lot of sediment. During long-term use of the equipment, impurities are easily attached between the valve body and the ball crown sealing surface, increasing the risk of valve jamming and sealing failure. In addition, the sealing structure between the valve body and the ball crown is prone to aging, resulting in a decrease in sealing performance.

[0005] 2. During the operation of large-diameter valves, the pressure in the valve cavity is relatively high, and there is a risk of the valve stem exploding and falling out.

[0006] Based on this, the present invention designs a high-sealing eccentric hemispherical valve and a method thereof to solve the above problems. Summary of the invention

[0007] In view of the above-mentioned shortcomings of the prior art, the present invention provides an eccentric hemispherical valve with high sealing performance and a method thereof.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0009] An eccentric hemispherical valve with high sealing performance comprises a valve body and a hemispherical valve core;

[0010] The valve body is provided with a valve cavity, and two sides of the valve body are respectively provided with a liquid inlet and a liquid outlet, and the liquid inlet and the liquid outlet are connected to the valve cavity;

[0011] The upper end and the lower end of the valve body are respectively provided with an upper flange and a lower flange, an upper valve stem is rotatably mounted inside the upper flange, and a lower valve stem is rotatably mounted inside the lower flange;

[0012] A hemispherical valve core is rotatably arranged in the valve cavity, and the upper and lower ends of the hemispherical valve core are fixedly connected to the upper valve stem and the lower valve stem respectively, and the cross section of the hemispherical valve core is an arc;

[0013] A valve seat is arranged on one side of the liquid outlet of the valve body, and a ball crown is arranged on the outer edge of the hemispherical valve core for abutting against the valve seat to achieve a sealing effect on the valve body;

[0014] A multi-stage sealing mechanism is provided between the upper valve stem and the upper flange to prevent leakage at the dynamic seal of the upper valve stem;

[0015] A soft and hard double sealing mechanism is arranged between the ball crown and the valve seat; the soft and hard double sealing mechanism comprises a main sealing ring and a self-cleaning elastic hard sealing assembly, the sealing surface of the valve seat is fixedly mounted with a main sealing ring for contacting with the sealing surface of the ball crown, and the self-cleaning elastic hard sealing assembly is arranged on the valve seat to ensure the sealing performance of the valve body in the event of failure of the main sealing ring;

[0016] A low-torque rotating mechanism for reducing the torque of the upper valve stem and the lower valve stem is provided between the lower valve stem and the lower flange;

[0017] The self-cleaning elastic hard sealing assembly comprises a first dustproof ring, a second dustproof ring, a valve seat O-ring and an elastic sealing assembly. The first dustproof ring and the second dustproof ring are respectively fixedly installed at both ends of the valve seat. The first dustproof ring and the second dustproof ring are used to prevent external impurities from entering the gap between the valve seat and the valve body; at least two valve seat O-rings are fixedly installed at one end of the valve seat close to the ball crown; the elastic sealing assembly is installed between the valve seat and the valve body;

[0018] The elastic sealing assembly includes a spring and a floating anti-dropout pin. A plurality of springs are fixedly installed between the valve seat and the valve body at equal intervals along the radial direction of the liquid outlet of the valve body. The valve seat is fixedly connected to the valve body through a plurality of floating anti-dropout pins. The floating anti-dropout pins are also distributed at equal intervals along the radial direction of the liquid outlet of the valve body.

[0019] Furthermore, a gap is provided between the floating anti-drop pin and the valve seat to allow the valve seat to move horizontally by 3.75 millimeters, and the matching gap between the stand of the valve seat and the valve body is set to 3 millimeters.

[0020] Furthermore, the self-cleaning elastic hard sealing component also includes a scraper, and the sealing surface of the valve seat is fixedly mounted with a scraper whose cutting edge extends along the arc of the spherical cap, and the scraper fits tightly against the sealing surface of the spherical cap.

[0021] Furthermore, the multi-stage sealing mechanism includes a packing gland, a high-performance combined packing, a sealing ring, a valve stem O-ring and four open rings. The upper valve stem adopts a "T"-shaped structure, and the "T"-shaped step of the upper valve stem is rotatably connected to the upper flange through a bearing; a packing gland, a sealing ring and four open rings are arranged in sequence from top to bottom between the side surface of the upper valve stem and the inner wall of the upper flange and located on the upper side of the "T"-shaped step of the upper valve stem.

[0022] Furthermore, the packing gland is fixedly connected to the upper flange by bolts;

[0023] A plurality of valve stem O-rings are arranged between the sealing ring and the upper valve stem;

[0024] High-performance combined packing is filled between the packing gland and the sealing ring;

[0025] The four open rings are in close contact with the bearings installed on the outside of the upper valve stem.

[0026] Furthermore, the low-torque rotating mechanism includes a lubricated composite bearing and a thrust bearing. The lubricated composite bearing is arranged between the hemispherical valve core and the lower flange, and the lubricated composite bearing serves as the main rotating structure between the hemispherical valve core and the lower flange; the thrust bearing is arranged between the hemispherical valve core and the lubricated composite bearing, and is used to bear and transmit axial loads.

[0027] Furthermore, the sealing surfaces of the ball crown and the valve seat are sprayed with hard alloy for increasing the wear resistance of the sealing surfaces.

[0028] In order to better achieve the purpose of the present invention, the present invention also provides a method for using a high-sealing eccentric hemispherical valve, comprising the following steps:

[0029] S1: When using the valve assembly, connect the valve body to the pipeline;

[0030] S2: By controlling the rotation of the upper valve stem, the hemispherical valve core is driven to rotate in the valve cavity in cooperation with the lower valve stem to close the valve;

[0031] S3: When the hemispherical valve core and the valve body are fully opened and closed, the scraper fits tightly against the sealing surface of the ball crown to scrape away the granular medium and impurities adhering to the surface of the ball core;

[0032] S4: When the valve is fully closed, the elastic secondary sealing structure between the ball crown and the valve seat is realized by the cooperation of the spring and the floating anti-drop pin, and the elastic pre-tightening function of the valve seat is realized by the spring.

[0033] Compared with the prior art, the present invention has the following beneficial effects: 1. In the present invention, an elastic secondary sealing structure between the ball crown and the valve seat is realized by the cooperation of a spring and a floating anti-drop pin, which is more conducive to sealing, and the elastic pre-tightening function of the valve seat is realized by the spring, so that the valve seat always has the function of compensating the load, so that in the event of failure of the main seal, the elastic secondary seal can still ensure the sealing performance of the valve and meet the reliable sealing conditions.

[0034] 2. By adopting a sealing ring equipped with multiple EPDM valve stem O-rings and the coordinated effect of high-performance combined packing, a multi-pass sealing structure is realized to achieve an effective and long-term sealing effect. The four-open ring clamps the "T"-shaped step of the main upper valve stem. The upper valve stem can only be removed after the four-open ring is removed, thereby avoiding the safety hazard of explosion of the upper valve stem.

[0035] 3. The lubricated composite bearing serves as the main rotating structure between the hemispherical valve core and the lower flange; the thrust bearing is arranged between the hemispherical valve core and the lubricated composite bearing to bear and transmit the axial load; the friction coefficient of the lubricated composite bearing is ≥., and the friction coefficient of the thrust bearing is. The weight of the hemispherical valve core of the super-large diameter valve body is in the tonnage level. The combination of the lubricated composite bearing and the thrust bearing greatly reduces the valve operating torque. The valve can adopt a low-torque operating actuator to save costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 A three-dimensional eccentric hemispherical valve with high sealing performance according to the present invention Figure 1 ;

[0038] Figure 2 A three-dimensional eccentric hemispherical valve with high sealing performance according to the present invention Figure 2 ;

[0039] Figure 3 A three-dimensional diagram of a hidden valve body of the present invention;

[0040] Figure 4 is a three-dimensional diagram of the valve seat of the present invention;

[0041] Figure 5 It is a right view of a high sealing eccentric hemispherical valve of the present invention;

[0042] Figure 6 For along Figure 5AA direction cross-sectional view;

[0043] Figure 7 for Figure 6 The enlarged view of point B in the middle;

[0044] Figure 8 for Figure 6 Enlarged view of point C in the middle;

[0045] Fig. 9 for Figure 6 Enlarged view of point D in the middle.

[0046] The numbers in the figure represent:

[0047] 10. Valve body; 101. Valve cavity; 102. Liquid inlet; 103. Liquid outlet; 11. Hemispherical valve core; 12. Upper valve stem; 13. Lower valve stem; 14. Upper flange; 15. Lower flange; 16. Ball crown; 17. Valve seat; 2. Multi-stage sealing mechanism; 21. Packing gland; 22. High-performance combined packing; 23. Sealing ring; 24. Stem O-ring; 25. Four open rings; 3. Soft and hard double sealing mechanism; 31. Main sealing ring; 32. Scraper; 33. First dust ring; 34. Second dust ring; 35. Valve seat O-ring; 36. Spring; 37. Floating anti-drop pin; 4. Low-torque rotating mechanism; 41. Lubricated composite bearing; 42. Thrust bearing. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] The terms “left”, “right”, “front”, “back”, “up” and “down” mentioned in the following description are oriented in the viewing direction of the front view.

[0050] Embodiment 1: In some embodiments, please refer to the drawings of the specification Figure 1-Figure 9 , a high sealing eccentric hemispherical valve, comprising a valve body 10 and a hemispherical valve core 11;

[0051] The valve body 10 is provided with a valve cavity 101, and the two sides of the valve body 10 are respectively provided with a liquid inlet 102 and a liquid outlet 103, and the liquid inlet 102 and the liquid outlet 103 are connected to the valve cavity 101;

[0052] The upper end and the lower end of the valve body 10 are respectively provided with an upper flange 14 and a lower flange 15, wherein the upper valve stem 12 is rotatably mounted inside the upper flange 14, and the lower valve stem 13 is rotatably mounted inside the lower flange 15;

[0053] A hemispherical valve core 11 is rotatably disposed in the valve cavity 101. The upper and lower ends of the hemispherical valve core 11 are fixedly connected to the upper valve stem 12 and the lower valve stem 13 respectively. The cross section of the hemispherical valve core 11 is arc-shaped.

[0054] A valve seat 17 is disposed on one side of the liquid outlet 103 of the valve body 10, and a ball crown 16 is disposed on the outer edge of the hemispherical valve core 11 for abutting against the valve seat 17 to achieve a sealing effect on the valve body 10;

[0055] A multi-stage sealing mechanism 2 is provided between the upper valve stem 12 and the upper flange 14 to prevent leakage at the dynamic seal of the upper valve stem 12;

[0056] A soft and hard double sealing mechanism 3 is arranged between the ball crown 16 and the valve seat 17; the soft and hard double sealing mechanism 3 includes a main sealing ring 31 and a self-cleaning elastic hard sealing component. The sealing surface of the valve seat 17 is fixedly installed with a main sealing ring 31 for abutting against the sealing surface of the ball crown 16. The main sealing ring 31 is made of EPDM material and realizes a soft seal on the valve body 10 when the ball crown 16 and the valve seat 17 are closed; the self-cleaning elastic hard sealing component is arranged on the valve seat 17 to ensure the sealing performance of the valve body 10 when the main sealing ring 31 fails.

[0057] A low-torque rotating mechanism 4 for reducing the torque of the upper valve stem 12 and the lower valve stem 13 is provided between the lower valve stem 13 and the lower flange 15 .

[0058] Embodiment 2: In some embodiments, Figure 7 As shown in the figure, as a preferred embodiment of the present invention, the self-cleaning elastic hard sealing assembly includes a scraper 32, a first dust ring 33, a second dust ring 34, a valve seat O-ring 35, a spring 36 and a floating anti-drop pin 37. The sealing surface of the valve seat 17 is fixedly mounted with a scraper 32 whose cutting edge extends along the arc of the ball crown 16. The scraper 32 fits tightly with the sealing surface of the ball crown 16. In the process of fully opening and fully closing the hemispherical valve core 11 and the valve body 10, the scraper 32 fits tightly with the sealing surface of the ball crown 16 to scrape off the granular medium and impurities bonded to the surface of the ball core.

[0059] The first dustproof ring 33 and the second dustproof ring 34 are respectively fixedly installed at both ends of the valve seat 17, and the first dustproof ring 33 and the second dustproof ring 34 are used to prevent external impurities from entering the gap between the valve seat 17 and the valve body 10; at least two valve seat O-rings 35 are fixedly installed at one end of the valve seat 17 close to the ball crown 16, and the valve seat O-rings 35 are made of EPDM material;

[0060] A plurality of springs 36 are fixedly installed between the valve seat 17 and the valve body 10 at equal intervals along the radial direction of the liquid outlet 103 of the valve body 10, and the valve seat 17 is fixedly connected to the valve body 10 through a plurality of floating anti-dropout pins 37, and the floating anti-dropout pins 37 are also distributed at equal intervals along the radial direction of the liquid outlet 103 of the valve body 10; a gap is provided between the floating anti-dropout pins 37 and the valve seat 17 so that the valve seat 17 has a horizontal movement of 3.75 mm, and at the same time, the matching gap between the stand of the valve seat 17 and the valve body 10 is set to 3 mm;

[0061] In the present invention, an elastic secondary sealing structure between the ball crown 16 and the valve seat 17 is realized by the cooperation of the spring 36 and the floating anti-drop pin 37, which is more conducive to sealing. The spring 36 realizes the elastic pre-tightening function of the valve seat 17, so that the valve seat 17 always has the function of compensating the load, so that in the event of failure of the main seal, the elastic secondary seal can still ensure the sealing performance of the valve.

[0062] In the present invention, the calculated value of the spring preload force at the valve seat is FMY=nP'S (n is the number of springs, P' is the stiffness of a single spring, and S is the compression of a single spring), and the resulting value is 19072N.

[0063] The force of the medium pressing on the ball through the valve seat is calculated as FZJQ=πP(DJH2-DM2) / 4 (where P is the calculated pressure, DJH is the outer diameter of the valve seat piston cylinder, and DM is the sealing surface diameter). The resulting value is 164314N.

[0064] The friction force calculation of the O-ring is FMM=πDJHbm'Zqof0 (where DJH is the outer diameter of the valve seat piston cylinder, bm' is the contact width between the O-ring and the valve seat support ring, Z is the number of O-rings, qo is the O-ring sealing pressure ratio, Z is the number of O-rings, and f0 is the friction coefficient of the O-ring). The result value is 6958N.

[0065] Calculation of the total force on the sealing surface: FMZ = FZJQ + FMY - FMM

[0066] The working specific pressure calculation on the valve seat sealing surface is q=FMZ / (2πRhcosα) (where R is the radius of the sphere, h is the projection width of the sealing surface, and α is the angle between the sealing surface and the flow channel direction), and the resulting value is q=4.64.

[0067] The required specific pressure of the sealing surface is qMF (where C is the sealing surface material coefficient, K is the specific pressure coefficient, P is the calculated pressure, and bM is the sealing surface width), the result value is 0.87

[0068] The allowable specific pressure of the sealing surface [qMF] is 5.0.

[0069] Therefore: qMF<q≤[qMF], which meets the reliable sealing condition.

[0070] The sealing surfaces of the ball crown 16 and the valve seat 17 are sprayed with hard alloy to increase the wear resistance of the sealing surfaces of the ball crown 16 and the valve seat 17 .

[0071] Embodiment 3: In some embodiments, Figure 8 As shown, as a preferred embodiment of the present invention, the multi-stage sealing mechanism 2 includes a packing gland 21, a high-performance combined packing 22, a sealing ring 23, a valve stem O-ring 24 and a four-open ring 25. The upper valve stem 12 adopts a "T"-shaped structure, and the "T"-shaped step of the upper valve stem 12 is rotatably connected to the upper flange 14 through a bearing; the packing gland 21, the sealing ring 23 and the four-open ring 25 are arranged in sequence from top to bottom between the side of the upper valve stem 12 and the inner wall of the upper flange 14 and located on the upper side of the "T"-shaped step of the upper valve stem 12;

[0072] The packing gland 21 is fixedly connected to the upper flange 14 by bolts;

[0073] A plurality of valve stem O-rings 24 are arranged between the sealing ring 23 and the upper valve stem 12, and the valve stem O-rings 24 are made of EPDM material;

[0074] A high-performance combined packing 22 is filled between the packing gland 21 and the sealing ring 23. The high-performance combined packing 22 is composed of flexible graphite packing, stainless steel wire flexible graphite packing, and flexible graphite packing from top to bottom, and a gasket is provided between each layer.

[0075] The four open rings 25 are in close contact with the bearings installed on the outer side of the upper valve stem 12 .

[0076] In the present invention, a multi-pass sealing structure is realized by adopting a sealing ring 23 equipped with multiple EPDM valve stem O-rings 24 and a high-performance combined packing 22, thereby achieving an effective and long-term sealing effect. In addition, the four open rings 25 clamp the "T"-shaped step of the upper valve stem 12. The upper valve stem 12 can only be removed after the four open rings 25 are removed, thereby avoiding the safety hazard of explosion of the upper valve stem 12.

[0077] Embodiment 4: In some embodiments, Fig. 9As shown, as a preferred embodiment of the present invention, the low-torque rotating mechanism 4 includes a lubricated composite bearing 41 and a thrust bearing 42. The lubricated composite bearing 41 is arranged between the hemispherical valve core 11 and the lower flange 15, and the lubricated composite bearing 41 serves as the main rotating structure between the hemispherical valve core 11 and the lower flange 15; the thrust bearing 42 is arranged between the hemispherical valve core 11 and the lubricated composite bearing 41, and is used to bear and transmit axial loads; the friction coefficient of the lubricated composite bearing 41 is ≥0.05, and the friction coefficient of the thrust bearing 42 is 0.002. The weight of the hemispherical valve core 11 of the super-large-caliber valve body 10 is in the tonnage level. The cooperation of the lubricated composite bearing 41 and the thrust bearing 42 greatly reduces the valve operating torque, and the valve can adopt a low-torque operating actuator to save costs.

[0078] Embodiment 5: In some embodiments, Figure 1-Figure 9 As shown, as a preferred embodiment of the present invention, a method for using a high-sealing eccentric hemispherical valve comprises the following steps:

[0079] S1: When using the valve assembly, connect the valve body 10 to the pipeline;

[0080] S2: By controlling the upper valve stem 12 to rotate, the hemispherical valve core 11 is driven to rotate in the valve cavity 101 in cooperation with the lower valve stem 13 to close the valve;

[0081] S3: During the process of fully opening and fully closing the hemispherical valve core 11 and the valve body 10, the scraper 32 is in close contact with the sealing surface of the ball crown 16 to scrape away the granular medium and impurities adhering to the surface of the ball core;

[0082] S4: When the valve is fully closed, the elastic secondary sealing structure between the ball crown 16 and the valve seat 17 is realized by the cooperation of the spring 36 and the floating anti-drop pin 37, and the elastic pre-tightening function of the valve seat 17 is realized by the spring 36.

[0083] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An eccentric hemispherical valve with high sealing performance, comprising a valve body (10) and a hemispherical valve core (11), characterized in that: A valve cavity (101) is provided in the valve body (10), and a liquid inlet (102) and a liquid outlet (103) are respectively provided on two sides of the valve body (10), and the liquid inlet (102) and the liquid outlet (103) are communicated with the valve cavity (101); The upper end and the lower end of the valve body (10) are respectively provided with an upper flange (14) and a lower flange (15); an upper valve stem (12) is rotatably mounted inside the upper flange (14), and a lower valve stem (13) is rotatably mounted inside the lower flange (15); A hemispherical valve core (11) is rotatably arranged in the valve cavity (101), and the upper and lower ends of the hemispherical valve core (11) are respectively fixedly connected to the upper valve stem (12) and the lower valve stem (13), and the cross section of the hemispherical valve core (11) is arc-shaped; A valve seat (17) is provided on one side of the liquid outlet (103) of the valve body (10), and a spherical crown (16) is provided on the outer edge of the hemispherical valve core (11) for abutting against the valve seat (17) to achieve a sealing effect on the valve body (10); A multi-stage sealing mechanism (2) is provided between the upper valve stem (12) and the upper flange (14) for preventing leakage at the dynamic seal of the upper valve stem (12); A soft and hard double sealing mechanism (3) is arranged between the ball crown (16) and the valve seat (17); the soft and hard double sealing mechanism (3) comprises a main sealing ring (31) and a self-cleaning elastic hard sealing component; the sealing surface of the valve seat (17) is fixedly mounted with the main sealing ring (31) for abutting against the sealing surface of the ball crown (16); the self-cleaning elastic hard sealing component is arranged on the valve seat (17) for ensuring the sealing performance of the valve body (10) in the event of failure of the main sealing ring (31); A low-torque rotating mechanism (4) for reducing the torque of the upper valve stem (12) and the lower valve stem (13) is provided between the lower valve stem (13) and the lower flange (15); The self-cleaning elastic hard sealing assembly comprises a first dustproof ring (33), a second dustproof ring (34), a valve seat O-ring (35) and an elastic sealing assembly. The first dustproof ring (33) and the second dustproof ring (34) are respectively fixedly mounted on both ends of the valve seat (17). The first dustproof ring (33) and the second dustproof ring (34) are used to prevent external impurities from entering the gap between the valve seat (17) and the valve body (10). At least two valve seat O-rings (35) are fixedly mounted on one end of the valve seat (17) close to the ball crown (16). The elastic sealing assembly is mounted between the valve seat (17) and the valve body (10). The elastic sealing component includes a spring (36) and a floating anti-dropout pin (37). A plurality of springs (36) are fixedly installed between the valve seat (17) and the valve body (10) at equal intervals along the radial direction of the liquid outlet (103) of the valve body (10). The valve seat (17) is fixedly connected to the valve body (10) via a plurality of floating anti-dropout pins (37). The floating anti-dropout pins (37) are also distributed at equal intervals along the radial direction of the liquid outlet (103) of the valve body (10).

2. The high sealing eccentric hemispherical valve according to claim 1, characterized in that: A gap of 3.75 millimeters is provided between the floating anti-drop pin (37) and the valve seat (17) to allow the valve seat (17) to move horizontally, and a matching gap of 3 millimeters is provided between the stand of the valve seat (17) and the valve body (10).

3. The high sealing eccentric hemispherical valve according to claim 2, characterized in that: The self-cleaning elastic hard sealing component also includes a scraper (32). The sealing surface of the valve seat (17) is fixedly mounted with the scraper (32) whose cutting edge extends along the arc of the spherical cap (16). The scraper (32) is tightly fitted to the sealing surface of the spherical cap (16).

4. The high sealing eccentric hemispherical valve according to claim 1, characterized in that: The multi-stage sealing mechanism (2) comprises a packing gland (21), a high-performance combined packing (22), a sealing ring (23), a valve stem O-ring (24) and a four-open ring (25); the upper valve stem (12) adopts a "T"-shaped structure; the "T"-shaped step of the upper valve stem (12) is rotatably connected to the upper flange (14) via a bearing; the packing gland (21), the sealing ring (23) and the four-open ring (25) are arranged in sequence from top to bottom between the side surface of the upper valve stem (12) and the inner wall of the upper flange (14) and located on the upper side of the "T"-shaped step of the upper valve stem (12).

5. The high sealing eccentric hemispherical valve according to claim 4, characterized in that: The packing gland (21) is fixedly connected to the upper flange (14) by bolts; A plurality of valve stem O-rings (24) are arranged between the sealing ring (23) and the upper valve stem (12); A high-performance combined packing (22) is filled between the packing gland (21) and the sealing ring (23); The four open rings (25) are in close contact with the bearings installed on the outer side of the upper valve stem (12).

6. The high sealing eccentric hemispherical valve according to claim 1, characterized in that: The low-torque rotating mechanism (4) comprises a lubricated composite bearing (41) and a thrust bearing (42); the lubricated composite bearing (41) is arranged between the hemispherical valve core (11) and the lower flange (15); the lubricated composite bearing (41) serves as the main rotating structure between the hemispherical valve core (11) and the lower flange (15); and the thrust bearing (42) is arranged between the hemispherical valve core (11) and the lubricated composite bearing (41) to bear and transmit axial loads.

7. The high sealing eccentric hemispherical valve according to claim 1, characterized in that: The sealing surfaces of the spherical crown (16) and the valve seat (17) are sprayed with hard alloy for increasing the wear resistance of the sealing surfaces.

8. A method for using a high-sealing eccentric hemispherical valve, using the high-sealing eccentric hemispherical valve according to claim 3, characterized in that: The following steps are involved: S1: When using the valve assembly, connect the valve body (10) to the pipeline; S2: By controlling the upper valve stem (12) to rotate, the hemispherical valve core (11) is driven to rotate in the valve cavity (101) in cooperation with the lower valve stem (13), thereby closing the valve; S3: During the process of fully opening and fully closing the hemispherical valve core (11) and the valve body (10), the scraper (32) is in close contact with the sealing surface of the ball crown (16) to scrape away the granular medium and impurities adhering to the surface of the ball core; S4: When the valve is fully closed, the elastic secondary sealing structure between the ball crown (16) and the valve seat (17) is realized by the cooperation of the spring (36) and the floating anti-drop pin (37), and the elastic pre-tightening function of the valve seat (17) is realized by the spring (36).

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