Double-eccentric butterfly valve

Abstract

The double-eccentric butterfly valve comprises a valve body, a valve rod, a butterfly plate and a valve seat, an upper shaft hole and a lower shaft hole are formed in the upper end and the lower end of the valve body respectively, the valve rod sequentially penetrates through the upper shaft hole and the lower shaft hole, the portion, located in an inner cavity of the valve body, of the valve rod is in linkage connection with the butterfly plate, and the valve seat is made of elastic materials. The valve seat is installed on the inner wall of the valve body and used for abutting against the butterfly plate to form sealing fit when the valve is closed. The butterfly plate comprises a mounting main body, a sealing ring, a first linkage assembly and a second linkage assembly; when the valve is opened, the valve rod drives the sealing ring to move towards the direction close to the installation body through the first linkage assembly so that the sealing ring can be rapidly separated from the valve seat, and when the valve is closed, the valve rod drives the sealing ring to move towards the direction away from the installation body through the second linkage assembly so that the sealing ring can rapidly abut against the valve seat. The butterfly plate can be quickly separated from or abut against the floating valve seat at the moment of opening and closing the valve, so that abrasion of a valve sealing pair is reduced, and the service life of the valve is remarkably prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of valves, in particular to a double eccentric butterfly valve. Background Art

[0002] In order to ensure the pressure resistance and stability of the butterfly valve and avoid excessive extrusion between the valve disc and the valve seat, most existing butterfly valves adopt a double eccentric structure. The double eccentric structure means that the valve stem axis deviates from the center of both the butterfly disc and the valve body. After the valve stem drives the butterfly disc to rotate and open, the butterfly disc can quickly separate from the valve seat, greatly eliminating unnecessary excessive extrusion and scraping between the butterfly disc and the valve seat, reducing the torque when the butterfly valve is opened, reducing wear and extending the life of the valve seat.

[0003] In order to further improve the service life of the butterfly valve, a butterfly valve with a floating valve seat structure has emerged in the existing technology. Its valve seat adopts an elastic structure or a combination structure of a metal valve seat and a spring, so that the valve seat can float and compensate in the axial direction. Therefore, even if the valve seat sealing surface or the butterfly plate sealing surface is worn, the valve seat can always be driven by the elastic force to stick to the butterfly plate sealing surface.

[0004] For example, Chinese utility model patent application number CN202022899893.1 discloses a floating valve seat structure for a bidirectional soft-seal butterfly valve. The structure comprises a floating valve seat, which is sealed and pressed into the valve body by a sealing pressure ring. A flange is provided on the inner side of the valve body, cooperating with the floating valve seat. The flange is located on the side away from the sealing pressure ring, and a gap is left between the floating valve seat and the flange of the valve body. The floating valve seat has a trapezoidal groove on its end near the valve body, which contains a first sealing ring. A second sealing ring is provided on the side of the floating valve seat near the sealing pressure ring. A valve plate is provided within the valve body, cooperating with the floating valve seat. The end surface of the valve plate near the floating valve seat is spherical. This design utilizes a soft floating valve seat and an O-ring to achieve bidirectional sealing of the butterfly valve, offering outstanding characteristics such as wear resistance, stable sealing, and low technical difficulty.

[0005] However, this structure increases the contact time between the disc and seat during opening and closing. While this ensures the valve's sealing performance and extends its service life to a certain extent, if the contact time between the disc and seat during opening and closing is further reduced, the wear of the valve seal can be further reduced, significantly extending the valve's service life. Therefore, structural improvements are essential. Summary of the Invention

[0006] The purpose of the present invention is to provide a double eccentric butterfly valve. At the moment of valve opening and closing, the butterfly plate can quickly separate from or press against the floating valve seat, thereby reducing the wear of the valve sealing pair and significantly improving the service life of the valve.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a double-eccentric butterfly valve, comprising a valve body, a valve stem, a butterfly plate and a valve seat, wherein an upper shaft hole and a lower shaft hole are respectively provided at the upper and lower ends of the valve body, the valve stem is sequentially passed through the upper shaft hole and the lower shaft hole, and the valve stem is located in the inner cavity of the valve body and is linked to the butterfly plate, the valve seat is made of elastic material, the valve seat is installed on the inner wall of the valve body and is used to abut against the butterfly plate to form a sealing fit when the valve is closed; the butterfly plate comprises a mounting body, a sealing ring, a first linkage assembly and a second linkage assembly, and the sealing ring is movably connected to the mounting body through the first linkage assembly and the second linkage assembly; when the valve is opened, the valve stem drives the sealing ring to move toward the mounting body through the first linkage assembly so that it quickly separates from the valve seat, and when the valve is closed, the valve stem drives the sealing ring to move toward the direction away from the mounting body through the second linkage assembly so that it quickly approaches the valve seat.

[0008] By adopting the above technical solution, regardless of whether the valve seat is a fixed structure or a floating structure, at the moment of valve opening and closing, the valve stem can drive the sealing ring of the butterfly plate to quickly approach or move away from the valve seat, thereby reducing the wear of the valve sealing pair and significantly improving the service life of the valve.

[0009] The present invention is further configured such that the first linkage component includes a plurality of groups, the first linkage component includes a screw and a return spring, the sealing ring is provided with a guide groove for the side of the installation body to extend into, and a guide plate matching the guide groove is installed on the installation body, the sealing ring is installed with a limit ring at a position corresponding to the outer end of the guide groove, the limit ring is provided with a plurality of screw holes corresponding to the number of the first linkage component, one end of the screw is threadedly connected to the screw hole, the other end of the screw is provided with a smooth rod part, the guide plate is provided with a guide hole matching the smooth rod part, the return spring is sleeved on the outer periphery of the screw, and the two ends of the return spring are respectively abutted against the guide plate and the limit ring.

[0010] By adopting the above technical solution, the first linkage component is used to apply a pre-tightening force to the sealing ring toward the installation body, so that it can quickly detach from the valve seat under specific conditions. In addition, the guide structure design between the screw and the guide plate also makes the sealing ring move more smoothly and reliably.

[0011] The present invention is further configured such that the guide plate is connected to the mounting body via a locking screw, and the mounting body is provided with a recess for the screw head of the locking screw to be embedded in; the sealing ring is provided with a threaded groove at a position corresponding to the outer end of the guide groove, and the limiting ring is threadedly connected to the threaded groove.

[0012] By adopting the above technical solution, the positioning and installation of the guide plate and the limit ring can be realized, with a simple and reliable structure and very convenient disassembly and assembly.

[0013] The present invention is further configured such that the limit ring includes an installation ring and a pressing ring, the pressing ring is in threaded fit with the threaded groove, the screw hole is provided on the installation ring, the installation ring is arranged on the inner circumference of the pressing ring, and a conical annular limiting groove is provided at the inner end of the pressing ring, and a limiting flange that fits with the annular limiting groove is provided on the outer circumference of the installation ring.

[0014] By adopting the above technical solution, the limit ring adopts a combined manner of an installation ring and a pressing ring, which can realize the adjustment of the position of the screw hole on the installation ring, facilitate its alignment with the guide hole, so that the smooth and rapid insertion of the smooth rod part of the screw into the guide hole can be achieved when installing the screw.

[0015] The present invention is further configured such that a circular ring-shaped track groove is arranged along the circumferential direction on the inner end surface of the threaded groove, a plurality of grooves communicating with the track groove are arranged in a circumferential array on the inner end surface of the installation ring, balls are arranged in the grooves in a rolling manner, and part of the balls extends into the track groove and is in rolling fit with the track groove.

[0016] By adopting the above technical solution, a rolling structure is arranged between the installation ring and the pressing ring, which can reduce the rotational friction of the installation ring, make the rotation operation easier, and cause less wear.

[0017] The present invention is further configured such that the number of the second linkage components is two groups, the second linkage component includes a positioning adjustment sleeve, a linkage ball and a linkage ball plunger, the positioning adjustment sleeve is sleeved on the outer circumference of the valve stem, the positioning adjustment sleeves of the two groups of second linkage components are respectively arranged at the upper and lower ends of the butterfly plate, a positioning groove for the outer end of the corresponding positioning adjustment sleeve to be embedded is respectively arranged at the inner ends of the upper shaft hole and the lower shaft hole, a positioning recess is formed on the inner circumferential surface of the positioning groove, a positioning convex part that fits with the positioning recess is arranged on the positioning adjustment sleeve, a circular hole is arranged through the side part of the positioning adjustment sleeve, the linkage ball and the linkage ball plunger are arranged in the circular hole, an arc-shaped groove with a length of one-fourth of the arc is arranged on the outer circumferential surface of the valve stem, the arc-shaped groove includes an inclined groove section with a uniformly changing depth and a flat groove section with an unchanged depth, the flat groove section is arranged at the end with a deeper depth of the inclined groove section, part of the linkage ball extends into the arc-shaped groove and is in rolling fit with the arc-shaped groove, part of the linkage ball plunger extends out of the circular hole and abuts against one end of the sealing ring close to the installation main body, when the linkage ball rolls in the inclined groove section, the linkage ball plunger axially expands and contracts in the circular hole, and the sealing ring moves in the direction of approaching or departing from the installation main body.

[0018] By adopting the above technical solution, during the process that the valve stem drives the butterfly plate to rotate and close the valve, the linkage ball relatively slides from the flat groove section to the inclined groove section. When the linkage ball rolls in the flat groove section, the distance between the sealing ring and the installation main body remains unchanged. When the butterfly plate is about to be in sealing fit with the valve seat, the linkage ball moves to the inclined groove section. And when the linkage ball rolls in the inclined groove section, the linkage ball pushes the linkage ball plunger, and the linkage ball plunger pushes the sealing ring to move towards the valve seat. When the valve is fully closed, the sealing ring is pressed tightly against the valve seat surface, and at this time, the return spring is compressed to store energy. The opening operation is just the opposite. The linkage ball and the linkage ball plunger gradually move away from the sealing ring. Under the action of the return spring, the sealing ring quickly disengages from the valve seat, thereby greatly reducing the friction generated by the sealing pair during the opening and closing process of the valve.

[0019] The present invention is further configured such that an annular adjustment groove is respectively provided at a position on the outer circumference of the valve stem corresponding to the inner sides of the two positioning adjustment sleeves. A linkage sleeve is embedded in the annular adjustment groove. The linkage sleeve includes a first half-ring and a second half-ring. The ends of the first half-ring and the second half-ring are abutted to form an integral ring shape. A locking protrusion is respectively provided at both ends of the first half-ring, and a locking groove that fits with the corresponding locking protrusion is respectively provided at both ends of the second half-ring. The arc-shaped groove is provided on the outer circular surface of the first half-ring.

[0020] By adopting the above technical solution, the arc-shaped groove is provided on the split-type linkage sleeve instead of on the valve stem. Different linkage sleeves with different arc-shaped groove designs can be replaced according to actual situations to adapt to different valve seats, without replacing the entire valve stem, which can reduce production costs. At the same time, the linkage sleeve is wrapped in the corresponding annular adjustment sleeve, playing a fixing role, making its installation structure more convenient and stable.

[0021] The present invention is further configured such that the valve seat includes a valve seat main body, a connection portion with an L-shaped cross-section provided on the outer circumference of the valve seat main body, an elastic movable portion provided on the inner circumference of the valve seat main body, and a sealing portion provided on the inner side of the elastic movable portion. A pressing ring for pressing the valve seat against the inner wall of the valve body is further installed on the side of the valve body through fasteners, and an activity groove for the sealing portion of the valve seat to extend into is provided on the pressing ring. When the sealing portion is stressed, the elastic movable portion can move in the activity groove.

[0022] By adopting the above technical solution, the flexible lip-shaped valve seat ensures reliable closing, can automatically compensate for wear, and the activity groove allows the deformation of the valve seat and can also limit the excessive deformation of the valve seat.

[0023] The present invention is further configured such that a fireproof graphite gasket is clamped between the valve seat and the inner wall of the valve body, and an annular bending portion for pressing against the outer circular surface of the sealing ring is provided on the fireproof graphite gasket.

[0024] By adopting the above technical solution, it can be ensured that the valve can still maintain effective sealing under high temperature or fire conditions, preventing secondary disasters caused by medium leakage and ensuring the inherent safety of the system.

[0025] The present invention is further configured as follows: the valve stem includes an upper shaft rod, a lower shaft rod and a linkage sleeve, the lower end of the upper shaft rod is provided with a driving cam, the upper end of the lower shaft rod is provided with a driven cam coaxially arranged with the driving cam, a gasket is provided between the driving cam and the driven cam, the linkage sleeve is sleeved on the driving cam, the gasket and the outer periphery of the driven cam, a plurality of arc-shaped recesses are provided along the circumferential direction on the inner circular surface of the linkage sleeve, an elastic convex portion is formed between each two adjacent arc-shaped recesses, and a clearance hole is provided on the linkage sleeve corresponding to the outer periphery of each elastic convex portion, the outer periphery of the driving cam is provided with a plurality of driving protrusions for embedding the arc-shaped recesses, and the outer periphery of the driven cam is provided with a plurality of driven protrusions for embedding the arc-shaped recesses.

[0026] By adopting the above technical solution, firstly, the valve stem adopts a split structure. Since the valve stem passes through the valve body from top to bottom, and the upper end also extends upward to connect with the drive device, the overall structure is long, and the axial concentricity is difficult to ensure, which makes processing more difficult. Therefore, the split structure is conducive to the processing and assembly of the valve stem; secondly, a linkage sleeve is used to transmit the upper shaft rod and the lower shaft rod. It adopts a tooth engagement method for transmission, and the transmission ratio is high. When the butterfly plate is stuck or has been opened or closed in place, the lower shaft rod does not move, and the torque generated by the upper shaft rod will cause the elastic convex part of the linkage sleeve to deform, thereby causing the upper shaft rod to idle, avoiding excessive torque from damaging the butterfly plate or valve seat, and also preventing the drive device (such as a motor) from being damaged due to overload. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a perspective view of the entire embodiment 1; Figure 2 A cross-sectional view of the entire embodiment 1; Figure 3 for Figure 2 A schematic diagram of the enlarged structure of the middle part A; Figure 4 Schematic diagram of the installation structure of the limit ring in Example 1; Figure 5 A three-dimensional diagram of the linkage sleeve in Example 1; Figure 6 This is an exploded view of the linkage sleeve in Example 1; Figure 7 A cross-sectional view of the entire embodiment 2; Figure 8 for Figure 7 A schematic diagram of the enlarged structure of the middle part B; Figure 9Schematic diagram of the mating structure of the upper shaft rod, lower shaft rod and linkage bushing in Embodiment 2.

[0028] In the figure: 1, valve body; 2, valve stem; 3, butterfly plate; 4, valve seat; 5, upper shaft hole; 6, lower shaft hole; 7, mounting body; 8, sealing ring; 9, first linkage assembly; 10, second linkage assembly; 11, screw; 12, return spring; 13, guide groove; 14, guide plate; 15, limit ring; 16, screw hole; 17, smooth rod part; 18, guide hole; 19, locking screw; 20, relief groove; 21, thread groove; 22, mounting ring; 23, retaining ring; 24, annular limit groove; 25, limit flange; 26, track groove; 27, groove; 28, ball; 29, positioning and adjusting sleeve; 30, linkage ball; 31, linkage ball plunger; 32, positioning groove; 33, positioning recess; 34, positioning protrusion; 35, round hole; 36, arc groove; 37, inclined groove section; 38, flat groove section; 39, annular adjustment groove; 40, linkage sleeve; 41, first half ring; 42, second half ring; 43, locking protrusion; 44, locking groove; 45, valve seat body; 46, connecting part; 47, elastic movable part; 48, sealing part; 49, retaining ring; 50, movable groove; 51, fireproof graphite gasket; 52, annular bending part; 53, upper shaft rod; 54, lower shaft rod; 55, linkage bushing; 56, driving convex shaft; 57, driven convex shaft; 58, washer; 59, arc recess; 60, elastic protrusion; 61, relief hole; 62, driving protrusion; 63, driven protrusion. Detailed implementation manners

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] Embodiment 1: As shown in the appendix Figures 1 - 6The double eccentric butterfly valve shown includes a valve body 1, a valve stem 2, a butterfly plate 3 and a valve seat 4. Upper and lower shaft holes 5 and 6 are respectively formed at the upper and lower ends of the valve body 1. The valve stem 2 passes through the upper shaft hole 5 and the lower shaft hole 6 in sequence. An upper shaft sleeve can be arranged in the upper shaft hole 5 to cooperate with the valve stem 2, and a lower shaft sleeve can be arranged in the lower shaft hole 6 to cooperate with the valve stem 2. A packing seal assembly is arranged at the upper end of the upper shaft hole 5 for sealing, and a combination of an end cover and a gasket is arranged at the lower end of the lower shaft hole 6 for sealing; the part of the valve stem 2 located in the inner cavity of the valve body 1 is linked with the butterfly plate 3. Specifically, after the valve stem 2 and the butterfly plate 3 are inserted and matched, the pin is welded and fixed after passing through the inserted pin. The valve seat 4 is made of an elastic material. The valve seat 4 is installed on the inner wall of the valve body 1 and is used to abut against the butterfly plate 3 to form a sealing fit when the valve is closed; the butterfly plate 3 includes a mounting body 7, a sealing ring 8, a first linkage assembly 9 and a second linkage assembly 10. The sealing ring 8 is movably connected to the mounting body 7 through the first linkage assembly 9 and the second linkage assembly 10; when the valve is opened instantaneously, the valve stem 2 drives the sealing ring 8 to move towards the direction close to the mounting body 7 through the first linkage assembly 9 so that it quickly disengages from the valve seat 4. When the valve is closed instantaneously, the valve stem 2 drives the sealing ring 8 to move away from the mounting body 7 through the second linkage assembly 10 so that it quickly approaches the valve seat 4. Whether the valve seat 4 is a fixed structure or a floating structure, at the moment when the valve is opened and closed, the valve stem 2 can drive the sealing ring 8 of the butterfly plate 3 to quickly approach or move away from the valve seat 4, thereby reducing the wear of the valve sealing pair and significantly improving the service life of the valve.

[0031] As shown in the attached Figure 2 and attached Figure 3 figures, the number of the first linkage assemblies 9 is multiple groups. The first linkage assembly 9 includes a screw 11 and a return spring 12. A guide groove 13 for the side part of the mounting body 7 to extend into is arranged on one side of the sealing ring 8 close to the mounting body 7. And a guide plate 14 matched with the guide groove 13 is installed on the mounting body 7. A limit ring 15 is installed at the position of the sealing ring 8 corresponding to the outer end of the guide groove 13. A plurality of screw holes 16 equal in number to the first linkage assembly 9 are arranged on the limit ring 15. One end of the screw 11 is threadedly connected to the screw hole 16, and an internal hexagonal groove is arranged at the end of the screw 11 to facilitate the insertion of a hexagonal wrench for rotating the screw 11. The other end of the screw 11 is provided with a smooth rod part 17, that is, the outer cylindrical surface is smooth. A guide hole 18 matched with the smooth rod part 17 is formed on the guide plate 14. The return spring 12 is sleeved on the outer periphery of the screw 11, and the two ends of the return spring 12 respectively abut against the guide plate 14 and the limit ring 15. The first linkage assembly 9 is used to apply a pre-tightening force to the sealing ring 8 towards the direction of the mounting body 7 so that it can quickly disengage from the valve seat 4 under specific conditions. On this basis, the guiding structure design between the screw 11 and the guide plate 14 also makes the movement of the sealing ring 8 more stable and reliable.

[0032] As shown in the appendix Figure 3 As shown, the guide plate 14 is connected to the mounting body 7 by a locking screw 19, and a relief groove 20 for the screw head of the locking screw 19 to be embedded is provided on the mounting body 7; a thread groove 21 is provided at the position corresponding to the outer end of the guide groove 13 of the sealing ring 8, and the limiting ring 15 is threadedly connected to the thread groove 21. A protrusion or recess for the user's hand to serve as a force application point can be provided on the limiting ring 15 to facilitate the rotation operation of the limiting ring 15. This design can achieve the positioning installation of the guide plate 14 and the limiting ring 15, with a simple and reliable structure and very convenient disassembly and assembly.

[0033] As shown in the appendix Figure 4 As shown, the limiting ring 15 includes a mounting ring 22 and a pressing ring 23. The pressing ring 23 is in threaded cooperation with the thread groove 21. The screw hole 16 is provided on the mounting ring 22. The mounting ring 22 is arranged on the inner circumference of the pressing ring 23, and a conical annular limiting groove 24 is provided at the inner end of the pressing ring 23. A limiting flange 25 that fits with the annular limiting groove 24 is provided on the outer circumference of the mounting ring 22. The limiting ring 15 adopts the combination of the mounting ring 22 and the pressing ring 23, which can realize the adjustment of the position of the screw hole 16 on the mounting ring 22, facilitate its alignment with the guide hole 18, so that the smooth rod portion 17 of the screw 11 can be smoothly and quickly inserted into the guide hole 18 when the screw 11 is installed.

[0034] As shown in the appendix Figure 4 As shown, a circular ring-shaped track groove 26 is provided along the circumferential direction on the inner end surface of the thread groove 21. A plurality of grooves 27 communicating with the track groove 26 are arranged in a circumferential array on the inner end surface of the mounting ring 22. A ball 28 is arranged to roll in the groove 27, and a part of the ball 28 extends into the track groove 26 to rollingly cooperate with the track groove 26. A rolling structure is provided between the mounting ring 22 and the pressing ring 23, which can reduce the rotational friction of the mounting ring 22, make the rotation operation easier, and cause less wear.

[0035] As shown in the appendix Figure 2 and the appendix Figure 3As shown, the number of the second linkage components 10 is two groups. The second linkage component 10 includes a positioning and adjusting sleeve 29, a linkage ball 30 and a linkage ball plunger 31. The positioning and adjusting sleeve 29 is sleeved on the outer periphery of the valve stem 2. The positioning and adjusting sleeves 29 of the two groups of second linkage components 10 are respectively arranged at the upper and lower ends of the butterfly plate 3. A positioning groove 32 for the outer end of the corresponding positioning and adjusting sleeve 29 to be embedded is respectively arranged at the inner ends of the upper shaft hole 5 and the lower shaft hole 6. A positioning recess 33 is arranged on the inner circumferential surface of the positioning groove 32. A positioning protrusion 34 that fits with the positioning recess 33 is arranged on the positioning and adjusting sleeve 29. A round hole 35 is arranged through the side part of the positioning and adjusting sleeve 29. The linkage ball 30 and the linkage ball plunger 31 are arranged in the round hole 35. An arc-shaped groove 36 with a length of one-fourth arc is arranged on the outer circumferential surface of the valve stem 2. The arc-shaped groove 36 includes an inclined groove section 37 with a uniformly changing depth and a flat groove section 38 with a constant depth. The flat groove section 38 is arranged at the end where the depth of the inclined groove section 37 is deeper. A part of the linkage ball 30 extends into the arc-shaped groove 36 and is in rolling fit with the arc-shaped groove 36. A part of the linkage ball plunger 31 extends out of the round hole 35 and abuts against one end of the sealing ring 8 close to the mounting body 7. When the linkage ball 30 rolls in the inclined groove section 37, the linkage ball plunger 31 axially expands and contracts in the round hole 35, and the sealing ring 8 moves in the direction close to or away from the mounting body 7. During the process that the valve stem 2 drives the butterfly plate 3 to rotate to close the valve, the linkage ball 30 relatively slides from the flat groove section 38 to the inclined groove section 37. When the linkage ball 30 rolls in the flat groove section 38, the distance between the sealing ring 8 and the mounting body 7 remains unchanged. When the butterfly plate 3 is about to be in sealing fit with the valve seat 4, the linkage ball 30 moves to the inclined groove section 37. When rolling in the inclined groove section 37, the linkage ball 30 pushes the linkage ball plunger 31, and the linkage ball plunger 31 pushes the sealing ring 8 to move in the direction close to the valve seat 4. When the valve is completely closed, the sealing ring 8 is pressed tightly on the surface of the valve seat 4, and at this time, the return spring 12 is compressed to store energy; the opening operation is the opposite. The linkage ball 30 and the linkage ball plunger 31 gradually move away from the sealing ring 8. Under the action of the return spring 12, the sealing ring 8 quickly disengages from the valve seat 4, thereby greatly reducing the friction generated by the sealing pair during the opening and closing process of the valve.

[0036] As shown in the appendix Figure 3 、 5As shown in FIGS. 6, an annular adjustment groove 39 is respectively formed on the outer periphery of the valve stem 2 at positions corresponding to the inner sides of two positioning and adjustment sleeves 29. A linkage sleeve 40 is embedded in the annular adjustment groove 39. The linkage sleeve 40 includes a first half-ring 41 and a second half-ring 42. The ends of the first half-ring 41 and the second half-ring 42 are abutted to form an integral ring shape. A locking projection 43 is respectively provided at both ends of the first half-ring 41, and a locking groove 44 that fits with the corresponding locking projection 43 is respectively provided at both ends of the second half-ring 42. The arc-shaped groove 36 is formed on the outer circular surface of the first half-ring 41. By arranging the arc-shaped groove 36 on the split linkage sleeve 40 instead of on the valve stem 2, the linkage sleeve 40 with different arc-shaped groove 36 designs can be replaced according to actual situations to adapt to different valve seats 4 without replacing the entire valve stem 2, which can reduce production costs. At the same time, the linkage sleeve 40 is wrapped in the corresponding annular adjustment sleeve, playing a fixing role and making its installation structure more convenient and stable.

[0037] As shown in the attached Figure 3 figures, the valve seat 4 includes a valve seat body 45, a connecting portion 46 with an L-shaped cross-section arranged on the outer circle of the valve seat body 45, an elastic movable portion 47 arranged on the inner circle of the valve seat body 45, and a sealing portion 48 arranged on the inner side of the elastic movable portion 47. A pressure ring 49 for pressing the valve seat 4 against the inner wall of the valve body 1 is further installed on the side portion of the valve body 1 through fasteners. The fasteners can be screws, and an activity groove 50 for the sealing portion 48 of the valve seat 4 to extend into is provided on the pressure ring 49. When the sealing portion 48 is stressed, the elastic movable portion 47 can move in the activity groove 50. The flexible lip-shaped valve seat 4 ensures reliable closing, can automatically compensate for wear, and the activity groove 50 not only allows the deformation of the valve seat 4 but also restricts the excessive deformation of the valve seat 4.

[0038] As shown in the attached Figure 3 figures, a fireproof graphite gasket 51 is clamped between the valve seat 4 and the inner wall of the valve body 1. An annular bending portion 52 for pressing against the outer circular surface of the sealing ring 8 is provided on the fireproof graphite gasket 51. This design can ensure that the valve can still maintain effective sealing under high-temperature or fire conditions, prevent the leakage of the medium from causing secondary disasters, and ensure the inherent safety of the system.

[0039] Embodiment 2: Different from the structure in which the valve stem 2 in Embodiment 1 is integrally processed, in this embodiment, the valve stem 2 adopts a split structure.

[0040] As shown in the attached Figures 7 - 9As shown, the valve stem 2 includes an upper shaft rod 53, a lower shaft rod 54 and a linkage sleeve 55. A driving convex shaft 56 is provided at the lower end of the upper shaft rod 53. A driven convex shaft 57 coaxial with the driving convex shaft 56 is provided at the upper end of the lower shaft rod 54. A washer 58 is arranged between the driving convex shaft 56 and the driven convex shaft 57. The linkage sleeve 55 is sleeved on the outer peripheries of the driving convex shaft 56, the washer 58 and the driven convex shaft 57. The linkage sleeve 55 can be made of plastic or silicone material. A plurality of arc-shaped concave portions 59 are arranged on the inner circular surface of the linkage sleeve 55 along the circumferential direction. An elastic convex portion 60 is formed between every two adjacent arc-shaped concave portions 59. And a relief hole 61 is provided at a position corresponding to the periphery of each elastic convex portion 60 on the linkage sleeve 55. A plurality of driving protrusions 62 for being embedded in the arc-shaped concave portions 59 are provided on the outer periphery of the driving convex shaft 56. A plurality of driven protrusions 63 for being embedded in the arc-shaped concave portions 59 are provided on the outer periphery of the driven convex shaft 57. First, the valve stem 2 is adopted with a split structure. Since the valve stem 2 penetrates through the valve body 1 from top to bottom and the upper end also needs to extend upward for connection with the driving device, it is relatively long and it is difficult to ensure the axial concentricity, resulting in difficult processing. Therefore, the split structure is beneficial to the processing and assembly of the valve stem 2. Secondly, the linkage sleeve 55 is adopted to drive and connect the upper shaft rod 53 and the lower shaft rod 54. It is driven in a gear meshing manner with a high transmission ratio. And when the butterfly plate 3 is jammed or has been opened or closed in place, the lower shaft rod 54 does not move, and the torque generated by the upper shaft rod 53 will cause the elastic convex portion 60 of the linkage sleeve 55 to deform, so that the upper shaft rod 53 idles, avoiding damage to the butterfly plate 3 or the valve seat 4 due to excessive torque and also preventing damage to the driving device (such as a motor) due to overload.

Claims

1. A double eccentric butterfly valve, comprising a valve body (1), a valve stem (2), a butterfly plate (3) and a valve seat (4), wherein the valve body (1) is provided with an upper shaft hole (5) and a lower shaft hole (6) at the upper and lower ends thereof, the valve stem (2) is sequentially passed through the upper shaft hole (5) and the lower shaft hole (6), and the valve stem (2) is located in the inner cavity of the valve body (1) and is linked to the butterfly plate (3), the valve seat (4) is made of an elastic material, and the valve seat (4) is mounted on the inner wall of the valve body (1) and is used to abut against the butterfly plate (3) to form a sealing fit when the valve is closed; the characteristics are: The butterfly plate (3) includes a mounting body (7), a sealing ring (8), a first linkage assembly (9), and a second linkage assembly (10). The sealing ring (8) is movably connected to the mounting body (7) through the first linkage assembly (9) and the second linkage assembly (10). At the moment when the valve is opened instantaneously, the valve stem (2) drives the sealing ring (8) to move towards the direction close to the mounting body (7) through the first linkage assembly (9) so that it quickly disengages from the valve seat (4). At the moment when the valve is closed instantaneously, the valve stem (2) drives the sealing ring (8) to move towards the direction away from the mounting body (7) through the second linkage assembly (10) so that it quickly approaches the valve seat (4).

2. The double-eccentric butterfly valve according to claim 1, wherein: The number of the first linkage assemblies (9) is multiple groups. The first linkage assembly (9) includes a screw rod (11) and a return spring (12). On one side of the sealing ring (8) close to the mounting body (7), there is a guide groove (13) for the side part of the mounting body (7) to extend into. And on the mounting body (7), there is a guide plate (14) matched with the guide groove (13). At the position of the sealing ring (8) corresponding to the outer end of the guide groove (13), a limit ring (15) is installed. The limit ring (15) is provided with a plurality of screw holes (16) equivalent to the number of the first linkage assemblies (9). One end of the screw rod (11) is threadedly connected to the screw hole (16). The other end of the screw rod (11) is provided with a smooth rod part (17). The guide plate (14) is provided with a guide hole (18) matched with the smooth rod part (17). The return spring (12) is sleeved on the outer periphery of the screw rod (11), and both ends of the return spring (12) are respectively abutted against the guide plate (14) and the limit ring (15).

3. The double-eccentric butterfly valve according to claim 2, wherein: The guide plate (14) is connected to the mounting body (7) through a locking screw (19). And on the mounting body (7), there is a relief groove (20) for the screw head of the locking screw (19) to be embedded. At the position of the sealing ring (8) corresponding to the outer end of the guide groove (13), there is a thread groove (21). The limit ring (15) is threadedly connected to the thread groove (21).

4. The double eccentric butterfly valve according to claim 3, characterized in that: The limit ring (15) includes a mounting ring (22) and a pressing ring (23). The pressing ring (23) is in threaded fit with the thread groove (21). The screw hole (16) is arranged on the mounting ring (22). The mounting ring (22) is arranged on the inner circumference of the pressing ring (23). And the inner end of the pressing ring (23) is provided with a conical annular limit groove (24). The outer circumference of the mounting ring (22) is provided with a limit flange (25) fitted with the annular limit groove (24).

5. The double eccentric butterfly valve according to claim 4, wherein: On the inner end face of the thread groove (21), a circular ring-shaped track groove (26) is arranged along the circumferential direction. On the inner end face of the mounting ring (22), a plurality of grooves (27) communicating with the track groove (26) are arranged in a circumferential array. A ball (28) is arranged to roll in the groove (27), and a part of the ball (28) extends into the track groove (26) to roll and cooperate with the track groove (26).

6. The double eccentric butterfly valve according to claim 2, characterized in that: The number of the second linkage components (10) is two. The second linkage components (10) include a positioning and adjusting sleeve (29), a linkage ball (30) and a linkage ball plunger (31). The positioning and adjusting sleeve (29) is sleeved on the outer periphery of the valve stem (2). The positioning and adjusting sleeves (29) of the two second linkage components (10) are respectively arranged at the upper and lower ends of the butterfly plate (3). A positioning groove (32) for the outer end of the corresponding positioning and adjusting sleeve (29) to be embedded is respectively arranged at the inner ends of the upper shaft hole (5) and the lower shaft hole (6). A positioning recess (33) is formed on the inner circumferential surface of the positioning groove (32). A positioning protrusion (34) that fits with the positioning recess (33) is arranged on the positioning and adjusting sleeve (29). A round hole (35) is formed through the side of the positioning and adjusting sleeve (29). The linkage ball (30) and the linkage ball plunger (31) are arranged in the round hole (35). An arc-shaped groove (36) with a length of one-fourth of a circle is arranged on the outer circumferential surface of the valve stem (2). The arc-shaped groove (36) includes an inclined groove section (37) with a uniformly changing depth and a flat groove section (38) with an unchanged depth. The flat groove section (38) is arranged at the end where the depth of the inclined groove section (37) is deeper. Part of the linkage ball (30) extends into the arc-shaped groove (36) and rolls with the arc-shaped groove (36). Part of the linkage ball plunger (31) extends out of the round hole (35) and abuts against one end of the sealing ring (8) close to the mounting body (7). When the linkage ball (30) rolls in the inclined groove section (37), the linkage ball plunger (31) axially expands and contracts in the round hole (35), and the sealing ring (8) moves in the direction close to or away from the mounting body (7).

7. The double eccentric butterfly valve according to claim 6, wherein: An annular adjusting groove (39) is respectively formed at the positions corresponding to the inner sides of the two positioning and adjusting sleeves (29) on the outer periphery of the valve stem (2). A linkage sleeve (40) is embedded in the annular adjusting groove (39). The linkage sleeve (40) includes a first half-ring (41) and a second half-ring (42). The ends of the first half-ring (41) and the second half-ring (42) abut against each other to form an integral ring shape. A locking protrusion (43) is respectively arranged at both ends of the first half-ring (41). A locking groove (44) that fits with the corresponding locking protrusion (43) is respectively arranged at both ends of the second half-ring (42). The arc-shaped groove (36) is formed on the outer circumferential surface of the first half-ring (41).

8. The double-eccentric butterfly valve according to claim 1, characterized in that: The valve seat (4) includes a valve seat body (45), an L-shaped connecting part (46) arranged at the outer circumference of the valve seat body (45), an elastic movable part (47) arranged at the inner circumference of the valve seat body (45), and a sealing part (48) arranged at the inner side of the elastic movable part (47). A pressing ring (49) for pressing the valve seat (4) against the inner wall of the valve body (1) is also installed on the side of the valve body (1) through fasteners. An activity groove (50) for the sealing part (48) of the valve seat (4) to extend into is arranged on the pressing ring (49). When the sealing part (48) is stressed, the elastic movable part (47) can move in the activity groove (50).

9. The double eccentric butterfly valve according to claim 8, wherein: A fireproof graphite gasket (51) is clamped between the valve seat (4) and the inner wall of the valve body (1), and an annular bending portion (52) for pressing against the outer circumferential surface of the sealing ring (8) is provided on the fireproof graphite gasket (51).

10. The double eccentric butterfly valve according to claim 1, characterized in that: The valve stem (2) includes an upper shaft rod (53), a lower shaft rod (54) and a linkage shaft sleeve (55). A driving convex shaft (56) is provided at the lower end of the upper shaft rod (53). A driven convex shaft (57) coaxial with the driving convex shaft (56) is provided at the upper end of the lower shaft rod (54). A washer (58) is arranged between the driving convex shaft (56) and the driven convex shaft (57). The linkage shaft sleeve (55) is sleeved on the outer circumferences of the driving convex shaft (56), the washer (58) and the driven convex shaft (57). A plurality of arc-shaped recesses (59) are arranged on the inner circumferential surface of the linkage shaft sleeve (55) in the circumferential direction. An elastic convex portion (60) is formed between every two adjacent arc-shaped recesses (59). A relief hole (61) is provided at a position corresponding to the periphery of each elastic convex portion (60) on the linkage shaft sleeve (55). A plurality of driving protrusions (62) for being embedded in the arc-shaped recesses (59) are provided on the outer circumference of the driving convex shaft (56). A plurality of driven protrusions (63) for being embedded in the arc-shaped recesses (59) are provided on the outer circumference of the driven convex shaft (57).

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