Compact online repairable ultra-low temperature butterfly valve

Abstract

The present invention belongs to the technical field of ultra-low temperature butterfly valves, and specifically relates to a compact online repairable ultra-low temperature butterfly valve. The butterfly valve provided by the present invention has a compact design, and combines the dual advantages of a wedge-type gate valve and a three-eccentric movable valve seat. After removing the extended valve cover, the internal parts such as the butterfly plate and the valve seat assembly can be directly taken out from the middle cavity. The entire process does not require the valve to be disassembled from the pipeline, and the internal parts can be replaced or repaired.

Description

Technical Field

[0001] The invention belongs to the technical field of ultra-low temperature butterfly valves, and in particular relates to a compact online repairable ultra-low temperature butterfly valve. Background Art

[0002] The butterfly valve is a valve that uses a disc-type opening and closing member to reciprocate about 90° to open, close or adjust the flow of the medium. The butterfly valve is not only simple in structure, small in size, light in weight, low in material consumption, small in installation size, small in driving torque, easy and quick to operate, but also has good flow regulation function and closing and sealing characteristics at the same time. It is one of the fastest-growing valve varieties in the past decade. In the low-temperature medium working conditions of the LNG system, higher requirements are put forward for the low-temperature butterfly valve, and functional requirements such as online repairability, high performance, zero leakage, and long life are put forward. At present, the hard-sealed butterfly valves produced at home and abroad are side-mounted butterfly plates; if a fault occurs during use and needs to be repaired; the medium in the pipeline must be closed and the entire valve must be removed from the pipeline for repair. The maintenance is troublesome and difficult, and it takes a long time to repair, and it affects the normal operation of the pipeline system; the traditional hard-sealed butterfly valve with a maintenance port has the disadvantages of being too large, the weight is mostly concentrated on one side of the maintenance port, it is difficult to install and position, and the maintenance port is equivalent to an additional leakage point. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a compact online repairable ultra-low temperature butterfly valve.

[0004] The technical solution adopted by the present invention is as follows: a compact online repairable ultra-low temperature butterfly valve, comprising a valve body, an extended valve cover, a valve stem, a butterfly plate, and a valve seat assembly, wherein the valve body comprises an inflow pipe connection part, an outflow pipe connection part, an extended valve cover connection part, and a valve body middle cavity part, wherein the inflow pipe connection part, the valve body middle cavity part, and the outflow pipe connection part are sequentially connected, and the inflow pipe connection part and the valve body middle cavity part are symmetrically arranged about the central axis of the valve body middle cavity part, wherein the extended valve cover connection part is formed by the upward protrusion of the valve body middle cavity part, and its center line coincides with the central axis of the valve body middle cavity part, and an installation opening is provided at the upper end of the extended valve cover connection part, and the extended valve cover is arranged above the installation opening and is fastened to the upper end of the extended valve cover connection part by a flange connection;

[0005] The valve stem passes through the extended valve cover and extends into the inner cavity of the middle cavity of the valve body and is connected to the butterfly plate through the first connecting bolt. The center line of the valve stem coincides with the center axis of the middle cavity of the valve body, and the butterfly plate is eccentrically arranged relative to the center axis of the middle cavity of the valve body.

[0006] The end of the inflow pipe connection part close to the valve body cavity part is convex to form a valve seat fixing convex ring, the valve seat assembly and the valve seat fixing convex ring are detachably connected and fixed, the minimum distance from the end of the valve seat fixing convex ring to the central axis of the valve body cavity part is a, and the minimum distance from the valve seat assembly to the central axis of the valve body cavity part is b, a≤b; the minimum distance from the inner wall of the extended valve cover connection part close to the side wall of the outflow pipe connection part and the outflow pipe connection part to the central axis of the valve body cavity part is c; the maximum distance from the sealing side surface of the butterfly plate and the valve seat assembly to the central axis of the valve body cavity part is d, and the maximum distance from the other side of the butterfly plate relative to the sealing side to the central axis of the valve body cavity part is e, d<c and e<a;

[0007] The valve stem can be rotated to have a closed position in which the sealing side of the butterfly plate is aligned with the valve seat and the valve seat is sealed, an open position in which the sealing side of the butterfly plate is offset from the valve seat to allow fluid to flow, and a disassembly position in which the sealing side of the butterfly plate is aligned with the outflow pipe connection part. When the valve stem is in the disassembly position, the butterfly plate can move along the center line of the valve stem to leave or enter the inner cavity of the central cavity part of the valve body.

[0008] The lower side of the middle cavity of the valve body is convex to form a bottom cover connecting part, and the outer end of the bottom cover connecting part is detachably connected to the bottom cover, and the valve stem is an integrated valve stem structure, the lower end of the valve stem extends into the bottom cover connecting part and the end is detachably connected to a limited disassembly block, and the outer diameter of the limited disassembly block is larger than the outer diameter of the end of the valve stem connected to it;

[0009] The inner cavity part of the bottom cover connecting part is composed of, from top to bottom, a first part which cooperates with the valve stem clearance, a second part which cooperates with the valve stem through the valve stem bearing, and a third part which cooperates with the limit disassembly block. The inner diameter of the second part is smaller than the outer diameter of the limit disassembly block to limit the limit disassembly block.

[0010] The limiting disassembly block is fastened to the lower end of the valve stem via a second connecting bolt.

[0011] The bottom cover and the lower end of the bottom cover connecting part are connected and fastened by a third connecting bolt, and a first sealing gasket is arranged between the bottom cover and the lower end of the bottom cover connecting part.

[0012] The inner circumference of the valve seat fixing convex ring is provided with a valve seat assembly mounting groove, and the valve seat assembly is arranged in the valve seat assembly mounting groove;

[0013] The valve seat assembly includes a hard sealing valve seat, a four-open ring, and a positioning block. The inner wall of the valve seat assembly installation groove is provided with an embedding groove, and the four-open ring is arranged in the embedding groove. The hard sealing valve seat and the positioning block are respectively located on both sides of the four-open ring and are fastened by a fourth connecting bolt. The hard sealing valve seat can cooperate with the butterfly plate seal.

[0014] A sealing groove is provided between the outer periphery of the hard sealing valve seat and the inner wall of the valve seat assembly installation groove. A single sealing energy storage ring is provided in the sealing groove. The sealing end of the single sealing energy storage ring is arranged away from the butterfly plate.

[0015] The single-seal energy storage ring includes an energy storage spring made of a hairspring alloy or INCONEL alloy, a jacket made of modified PTFE wrapped with high-strength alloy wire as the inner ribs, and a T-shaped retaining ring made of modified PTFE wrapped with high-strength alloy wire as the inner ribs. An opening is provided on the side of the jacket away from the butterfly plate, and the energy storage spring is arranged in the opening and wrapped by the jacket to limit the position of the energy storage spring. The T-shaped retaining ring is arranged on the side of the jacket away from the butterfly plate, and one end with a small area supports the energy storage spring.

[0016] A retaining ring and an adjusting bolt are arranged between the single sealing energy storage ring and the four open rings. The adjusting bolt passes through the positioning block, the four open rings and the retaining ring in sequence, and the end of the adjusting bolt is threadedly connected with the retaining ring.

[0017] The butterfly plate includes a butterfly plate body, a butterfly plate sealing ring, and a pressure plate. The butterfly plate body is circumferentially provided with a first positioning groove and a second positioning groove. The first positioning groove is arranged closer to the valve stem than the second positioning groove. The butterfly plate sealing ring is arranged in the first positioning groove, and the pressure plate is arranged in the second positioning groove. The pressure plate and the butterfly plate body are fastened by a fifth connecting bolt and the butterfly plate sealing ring is clamped between the two.

[0018] A second sealing gasket is arranged between the butterfly plate sealing ring and the butterfly plate body.

[0019] The beneficial effects of the present invention are as follows: the compact online repairable ultra-low temperature butterfly valve provided by the present invention is a top-mounted structure. When the valve needs to be repaired, it does not need to be removed from the pipeline, and the installation is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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 description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still belong to the scope of the present invention.

[0021] Figure 1 A side view of an embodiment of the present invention;

[0022] Figure 2 A cross-sectional view of an embodiment of the present invention;

[0023] Figure 3 for Figure 2 A magnified schematic diagram of part A;

[0024] Figure 4 A schematic diagram of the structure of the limit disassembly block and the bottom cover connecting part, and a schematic diagram of the structure of the limit disassembly block B;

[0025] Figure 5 is a schematic structural diagram of a first sealing gasket;

[0026] Figure 6 for Figure 3 A magnified schematic diagram of part A;

[0027] Figure 7 for Figure 2 A schematic diagram of the enlarged structure of part B;

[0028] Figure 8 The schematic diagram of the structure of the butterfly plate sealing ring is a soft and hard laminated metal sheet combined sealing structure in a natural state;

[0029] Fig. 9 for Figure 2 A schematic diagram of the enlarged structure of the middle C part;

[0030] Fig.10 for Fig. 9 A schematic diagram of the enlarged structure of part A;

[0031] Fig.11 for Figure 2 A schematic diagram of the enlarged structure of the D part;

[0032] In the figure, valve body 1; inflow pipe connection part 101; outflow pipe connection part 102; lengthened valve cover connection part 103; valve body middle cavity part 104; installation opening 105; bottom cover connection part 106; valve seat fixing convex ring 107; positioning pin shaft 108; lengthened valve cover 2; hemispherical convex ring part 201; upper valve cover 202; valve stem 3; butterfly plate 4; butterfly plate body 401; butterfly plate sealing ring 402; pressure plate 403; valve seat assembly 5; hard sealing valve seat 501; four open rings 502; positioning block 503; first connecting bolt 6; limit disassembly block 7; opening limit slide groove 701; axial channel -702; bottom cover-8; positioning boss-801; lip seal ring limiting convex ring part-802; guiding smooth inclined surface-803; limiting smooth convex surface-804; ball bearing-9; second connecting bolt-10; third connecting bolt-11; first sealing gasket-12; first plane-1201; transition inclined surface-1202; second plane-1203; fourth connecting bolt-13; single sealing energy storage ring-14; retaining ring-15; adjusting bolt-16; fifth connecting bolt-17; second sealing gasket-18; valve stem bearing-19; lip seal ring-20; third sealing gasket-21; annular groove-2101; drip plate-22;. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities with the same name or non-identical parameters. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. The subsequent embodiments will not explain this one by one.

[0035] The directions and positions mentioned in the present invention, such as "upper", "lower", "front", "back", "left", "right", "inside", "outside", "top", "bottom", "side", etc., are only for reference to the directions or positions of the drawings. Therefore, the directions and positions used are for explaining and understanding the present invention, but not for limiting the scope of protection of the present invention.

[0036] like Figure 1 , Figure 2 As shown, a compact online repairable ultra-low temperature butterfly valve comprises a valve body 1, an extended valve cover 2, a valve stem 3, a butterfly plate 4, and a valve seat assembly 5. The valve body 1 comprises an inflow pipe connection part 101, an outflow pipe connection part 102, an extended valve cover connection part 103, and a valve body middle cavity part 104. The inflow pipe connection part 101, the valve body middle cavity part 104, and the outflow pipe connection part 102 are sequentially connected, and the inflow pipe connection part 101 and the valve body middle cavity part 104 are symmetrically arranged about the central axis of the valve body middle cavity part 104. The extended valve cover connection part 103 is formed by the valve body middle cavity part 104 protruding upward, and its center line coincides with the central axis of the valve body middle cavity part 104. The upper end of the extended valve cover connection part 103 is provided with a mounting opening 105, and the extended valve cover 2 is arranged above the mounting opening 105 and is fastened to the upper end of the extended valve cover connection part 103 by flange connection;

[0037] The valve stem 3 passes through the extended valve cover 2 and extends into the inner cavity of the valve body middle cavity part 104 and is connected to the butterfly plate 4 through the first connecting bolt 6. The center line of the valve stem 3 coincides with the center axis of the valve body middle cavity part 104, and the butterfly plate 4 is eccentrically arranged relative to the center axis of the valve body middle cavity part 104.

[0038] The end of the inflow pipe connection part 101 close to the valve body cavity part 104 is raised to form a valve seat fixing convex ring 107, the valve seat assembly 5 is detachably connected and fixed to the valve seat fixing convex ring 107, the minimum distance from the end of the valve seat fixing convex ring 107 to the central axis of the valve body cavity part 104 is a, and the minimum distance from the valve seat assembly 5 to the central axis of the valve body cavity part 104 is b, a≤b; the minimum distance between the inner wall of the extended valve cover connection part 103 close to one side wall of the outflow pipe connection part 102 and the outflow pipe connection part 102 to the central axis of the valve body cavity part 104 is c; the maximum distance from the sealing side surface of the butterfly plate 4 and the valve seat assembly 5 to the central axis of the valve body cavity part 104 is d, and the maximum distance from the other side of the sealing side to the central axis of the valve body cavity part 104 is e, d<c and e<a;

[0039] The valve stem 3 can rotate to have a closed position where the sealing side of the butterfly plate 4 is aligned with the valve seat assembly 5 and the valve seat assembly 5 is sealed, an open position where the sealing side of the butterfly plate 4 is staggered with the valve seat assembly 5 to allow fluid to flow, and a disassembly position where the sealing side of the butterfly plate 4 is aligned with the outflow pipe connection part 102. When the valve stem 3 is in the disassembly position, the butterfly plate 4 can move along the center line of the valve stem 3 to leave or enter the inner cavity of the valve body middle cavity part 104. Through the above arrangement, when the valve stem 3 rotates to the disassembly position, the extended valve cover 2 can be opened, and the valve stem 3 and the butterfly plate 4 fixed on the valve stem 3 can be moved out from between the end of the valve seat fixing convex ring 107 and the inner wall of the extended valve cover connection part 103 close to the side wall of the outflow pipe connection part 102, and then the valve seat assembly 5 is removed and moved out from the installation opening 105.

[0040] The inner cavity of the valve body has a large bearing surface, small flow resistance, and a large fluid bearing surface; it has high pressure resistance. At the same time, this embodiment adopts a three-dimensional eccentric sealing structure. When closing the valve, the sealing surface of the butterfly plate moves along the three-dimensional eccentric displacement and only approaches the sealing surface of the valve body at the last moment. Under the action of eccentricity, the sealing surface of the butterfly plate and the sealing surface of the valve body are closer and closer, so the sealing surface of the butterfly plate and the sealing surface of the valve body are in very good and close contact, achieving a very good sealing effect and reliable sealing performance; when opening the valve, under the action of eccentricity, the butterfly plate only needs to turn a very small angle (2°~3°), and the sealing surface of the butterfly plate and the sealing surface of the valve body are completely separated, and there is no friction between the sealing surface of the butterfly plate and the sealing surface of the valve body, and the service life of the valve is long.

[0041] like Figure 3 As shown, the lower side of the middle cavity portion 104 of the valve body is convex to form a bottom cover connecting portion 106, and the outer end of the bottom cover connecting portion 106 is detachably connected to the bottom cover 8, and the valve stem 3 is an integrated valve stem structure, the lower end of the valve stem 3 extends into the bottom cover connecting portion 106 and the end is detachably connected to a limited disassembly block 7, and the outer diameter of the limited disassembly block 7 is larger than the outer diameter of the end of the valve stem 3 connected thereto;

[0042] The inner cavity part of the bottom cover connecting part 106 is composed of, from top to bottom, a first part which is clearance-matched with the valve stem 3, a second part which is matched with the valve stem 3 through the valve stem bearing 19, and a third part which is matched with the limit disassembly block 7. The inner diameter of the second part is smaller than the outer diameter of the limit disassembly block 7 to limit the limit disassembly block 7.

[0043] Specifically, the limiting disassembly block 7 is fastened to the lower end of the valve stem 3 via a second connecting bolt 10 .

[0044] like Figure 4 As shown, the middle of the outer peripheral wall of the limit disassembly block 7 is provided with an opening limit slide groove 701, and the inner wall of the bottom cover connecting part 106 is raised to form a positioning pin shaft 108. When the valve stem 3 switches between the closed position and the open position, the positioning pin shaft 108 is limited to slide in the opening limit slide groove 701. When the valve stem 3 is respectively in the closed position and the open position to the full opening, the positioning pin shaft 108 abuts against the two ends of the opening limit slide groove 701. The outer peripheral wall of the limit disassembly block 7 is provided with an axial channel 702, and the axial channel 702 is set corresponding to the position of the valve stem 3 when it is in the open position to the full opening. When the valve stem 3 is in the open position to the full opening, the positioning pin shaft 108 is located at the inner end of the axial channel 702 and can be moved out of the limit disassembly block 7 in the axial direction. The positioning pin shaft 108 is fixed to the inner wall of the bottom cover connecting part 106 by threaded connection. Through the above arrangement, it is ensured that when the valve stem 3 is in the open position to the full open degree, the limit disassembly block 7 can be removed. Therefore, the upstream pipeline is cut off, and then the valve is opened to drain the fluid, and then the limit disassembly block 7 is moved and the valve stem 3 is rotated to the disassembly position to complete the disassembly.

[0045] Specifically, Figure 5 As shown, the bottom cover 8 and the lower end of the bottom cover connecting portion 106 are connected and fastened by a third connecting bolt 11 , and a first sealing gasket 12 is provided between the bottom cover 8 and the lower end of the bottom cover connecting portion 106 .

[0046] The bottom cover 8 protrudes toward the inner cavity of the third part to form a positioning convex column 801, and an annular sealing groove is provided on the outer circumference of the positioning convex column 801. The first sealing gasket 12 is limited in the annular sealing groove. The cross-section of the first sealing gasket 12 is as follows: Figure 5As shown, its lower end is divided into a rectangular structure adapted to the annular sealing groove, and its upper surface from the inside to the outside are respectively a first plane 1201, a transition slope 1202, and a second plane 1203. The height of the first plane 1201 relative to the bottom surface is higher than the second plane 1203. When installing, the first sealing gasket 12 is first embedded in the annular sealing groove, and then the bottom cover 8 is connected to the bottom cover connecting part 106, and they are fastened by the third connecting bolt 11. In the process of rotating the third connecting bolt 11, the end face of the bottom cover connecting part 106 first abuts against the first plane 1201 and forms a gap with the transition slope 1202 and the second plane 1203, and then the third connecting bolt 11 is continued to be rotated to tighten, and the end face of the bottom cover connecting part 106 squeezes the first sealing gasket 12 to deform the first sealing gasket 12.

[0047] like Figure 6 As shown, a sealing groove is provided between the outer periphery of the upper end of the positioning convex column 801 and the inner wall of the third part, and a lip seal 20 is provided in the sealing groove. A lip seal limiting convex ring portion 802 is provided on the outer periphery of the upper end of the positioning convex column 801, and the lip seal limiting convex ring portion 802 forms a limit for the lip seal 20. One side of the lip seal limiting convex ring portion 802 is a guiding smooth inclined surface 803 for facilitating the insertion of the lip seal 20, and the other side is a limiting smooth convex surface 804 to prevent the lip seal 20 from sliding out. Under the action of a certain external force, the lip seal 20 can be removed without damage by slowly moving along the limiting smooth convex surface 804.

[0048] The upper end surface of the limit disassembly block 7 is connected and matched with the upper end surface of the third part through a ball bearing 9, the lower end surface of the limit disassembly block 7 is connected and matched with the upper end surface of the bottom cover 8 through a ball bearing 9, and there is a clearance fit between the limit disassembly block 7 and the inner wall of the third part. Through the above arrangement, the torque of the valve stem rotation is reduced.

[0049] like Figure 7 As shown, the inner circumference of the valve seat fixing convex ring 107 is provided with a valve seat assembly mounting groove, and the valve seat assembly 5 is arranged in the valve seat assembly mounting groove;

[0050] The valve seat assembly 5 includes a hard-sealed valve seat 501, a four-open ring 502, and a positioning block 503. The inner wall of the valve seat assembly installation groove is provided with an embedding groove, and the four-open ring 502 is arranged in the embedding groove. The hard-sealed valve seat 501 and the positioning block 503 are respectively located on both sides of the four-open ring 502 and are connected and fastened by the fourth connecting bolt 13. The hard-sealed valve seat 501 can be sealed with the butterfly plate 4. The valve seat assembly 5 is detachable through the above arrangement. The sealing surface of the hard-sealed valve seat 501 is made of surfacing stainless steel and cobalt-based hard alloy, and the sealing surface is wear-resistant, high-temperature-resistant and has a long service life.

[0051] A sealing groove is provided between the outer periphery of the hard sealing valve seat 501 and the inner wall of the valve seat assembly installation groove, and a single sealing energy storage ring 14 is provided in the sealing groove, and the sealing end of the single sealing energy storage ring 14 is arranged away from the butterfly plate 4, which effectively prevents leakage.

[0052] The single-seal energy storage ring 14 includes an energy storage spring made of a hairspring alloy or INCONEL alloy, a jacket made of modified PTFE wrapped with high-strength alloy wire as the inner ribs, and a T-shaped retaining ring made of modified PTFE wrapped with high-strength alloy wire as the inner ribs. An opening is provided on the side of the jacket away from the butterfly plate 4, and the energy storage spring is arranged in the opening and wrapped by the jacket to limit the position of the energy storage spring. The T-shaped retaining ring is arranged on the side of the jacket away from the butterfly plate 4, and one end with a small area supports the energy storage spring.

[0053] A retaining ring 15 is provided between the single seal energy storage ring 14 and the four open rings 502, and an adjusting bolt 16 is provided. The adjusting bolt 16 passes through the positioning block 503, the four open rings 502, and the retaining ring 15 in sequence, and its end is threadedly connected with the retaining ring 15. By rotating the adjusting bolt 16, the compression amount of the single seal energy storage ring 14 can be effectively adjusted, thereby adjusting the sealing performance.

[0054] The butterfly plate 4 includes a butterfly plate body 401, a butterfly plate sealing ring 402, and a pressure plate 403. The butterfly plate body 401 is circumferentially provided with a first positioning groove and a second positioning groove. The first positioning groove is arranged closer to the valve stem 3 than the second positioning groove. The butterfly plate sealing ring 402 is arranged in the first positioning groove, and the pressure plate 403 is arranged in the second positioning groove. The pressure plate 403 and the butterfly plate body 401 are connected and fastened by the fifth connecting bolt 17, and the butterfly plate sealing ring 402 is clamped between the two. A second sealing gasket 18 is arranged between the butterfly plate sealing ring 402 and the butterfly plate body 401. Among them, the surface of the butterfly plate body 401 is streamlined, so that the fluid resistance loss is small.

[0055] The butterfly plate sealing ring 402 can be as follows Figure 7 The pure metal sealing ring shown in FIG. Figure 8 The soft and hard laminated metal sheet combined seal shown, i.e., multiple layers of hard metal sealing sheets and multiple layers of soft sealing gaskets sandwiched between the hard metal sealing sheets, is squeezed and deformed under the pressure of the pressure plate 403. The outer periphery of the soft sealing gasket is a convex curved surface, and a part of the side of the soft sealing gasket close to the valve seat assembly 5 is convex relative to the hard metal sealing sheet and part is concave relative to the soft sealing gasket, providing a space for sealing deformation, having the dual advantages of metal hard sealing and elastic sealing, bidirectional pressure, reliable sealing, long service life, and very good sealing performance regardless of low temperature or high temperature conditions.

[0056] like Fig. 9As shown, a third sealing gasket 21 is provided between the extended valve cover 2 and the extended valve cover connecting portion 103, and a plurality of annular sealing member limiting grooves adapted to the third sealing gasket 21 are provided on the extended valve cover connecting portion 103. The third sealing gasket 21 is limited in the annular sealing member limiting groove and the upper end surface is convexly arranged relative to the annular sealing member limiting groove. The upper end surface of the third sealing gasket 21 is provided with a plurality of annular grooves 2101, as shown in FIG. Fig.10 As shown, the cross-section of the surface of the annular groove 2101 is an arc line with a radius of r1 and a depth of d in a natural state, and the lower end surface of the extended valve cover connecting part 103 is provided with a plurality of hemispherical convex ring portions 201 relative to the plurality of annular grooves 2101. The cross-section of the hemispherical convex ring portion 201 is a semicircle with a radius of r2, d<r2<r1. With this arrangement, under the tightening action of the bolts, the third sealing gasket 21 is deformed, and the inner wall of the annular groove 2101 fits the hemispherical convex ring portion 201, thereby increasing the sealing surface and improving the sealing effect.

[0057] like Figure 2 As shown, the extended valve cover 2 is provided with a drip plate 22 to increase the heat dissipation efficiency. The plate is made of plate, which is first flattened and connected to the valve cover by friction welding to ensure its flatness and performance. The heat dissipation of the valve is ensured.

[0058] like Fig.11 As shown, the upper valve cover 202 is welded on the extended valve cover 2. The upper valve cover 202 is integrally formed with the bracket and sealed with the valve stem 3 by packing. Through this setting, the overall bracket length can be freely controlled, and the length of the valve cover mold can remain unchanged, thereby saving costs; butt welding connection ensures concentricity and verticality. Ensure that the packing of the low-temperature valve will not freeze, avoid unsmooth switching, and scratch the packing and valve stem. Improve the performance of the butterfly valve.

[0059] A valve stem bearing 19 is provided between the lower end of the extended valve cover 2 and the valve stem 3. The valve stem bearing 19 used in this embodiment is made of self-lubricating tin bronze, with a small friction coefficient, specifically <0.16, which reduces torque and is flexible to open and close.

[0060] The present embodiment is provided with an end stem limiting and disassembling device, which can freely limit the stem and disassemble the stem. The movable valve seat structure can freely disassemble the single sealing energy storage ring, and the butterfly plate sealing ring structure can replace the sealing ring. The improvement of these several designs makes it possible to quickly disassemble the butterfly valve online. When the valve is repaired, it is only necessary to open the valve cover to lift out the butterfly plate and other accessories such as the elastic movable compensation valve seat, and repair or replace the accessories outside the on-site pipeline. Specifically, after removing the valve cover, the butterfly plate, the movable valve seat, and the valve seat pull plate and other internal parts can be directly taken out from the middle cavity. The whole process does not require the valve to be disassembled from the pipeline, and the internal parts can be replaced or repaired, achieving true non-destructive disassembly and assembly. Theoretically, the sealing ring can be replaced in every maintenance cycle, which greatly extends the service life of the valve and improves the overall performance of the ball valve. As long as the valve body is not damaged, the valve internal parts can be replaced an unlimited number of times, which greatly saves costs. The overall structure is compact and light in weight, the standard structure length does not need to be extended, it is easy to install and disassemble, the valve cover and valve body are easy to seal without leakage, and the valve seat and sealing ring are zero leakage.

[0061] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A compact online repairable ultra-low temperature butterfly valve, comprising a valve body (1), an extended valve cover (2), a valve stem (3), a butterfly plate (4), and a valve seat assembly (5), characterized in that: The valve body (1) comprises an inflow pipe connection part (101), an outflow pipe connection part (102), an extended valve cover connection part (103) and a valve body middle cavity part (104); the inflow pipe connection part (101), the valve body middle cavity part (104) and the outflow pipe connection part (102) are connected in sequence, and the inflow pipe connection part (101) and the valve body middle cavity part (104) are symmetrically arranged about the center axis of the valve body middle cavity part (104); the extended valve cover connection part (103) is formed by protruding upward from the valve body middle cavity part (104) and its center line coincides with the center axis of the valve body middle cavity part (104); the upper end of the extended valve cover connection part (103) is provided with a mounting opening (105); the extended valve cover (2) is arranged above the mounting opening (105) and is fastened to the upper end of the extended valve cover connection part (103) by a flange connection; The valve stem (3) passes through the extended valve cover (2) and extends into the inner cavity of the valve body middle cavity portion (104) and is connected to the butterfly plate (4) via a first connecting bolt (6); the center line of the valve stem (3) coincides with the center axis of the valve body middle cavity portion (104), and the butterfly plate (4) is eccentrically arranged relative to the center axis of the valve body middle cavity portion (104); One end of the inflow pipe connection part (101) close to the valve body cavity part (104) is raised to form a valve seat fixing convex ring (107), and the valve seat assembly (5) is detachably connected and fixed to the valve seat fixing convex ring (107). The minimum distance from the end of the valve seat fixing convex ring (107) to the center axis of the valve body cavity part (104) is a, and the minimum distance from the valve seat assembly (5) to the center axis of the valve body cavity part (104) is b, a≤b; the minimum distance between the side wall of the inner wall of the extended valve cover connection part (103) close to the outflow pipe connection part (102) and the center axis of the valve body cavity part (104) is c; the maximum distance from the sealing side surface of the butterfly plate (4) and the valve seat assembly (5) to the center axis of the valve body cavity part (104) is d, and the maximum distance from the other side opposite to the sealing side to the center axis of the valve body cavity part (104) is e, d<c and e<a; The valve stem (3) is rotatable to have a closed position in which the sealing side of the butterfly plate (4) is aligned with the valve seat assembly (5) and the valve seat assembly (5) is sealed, an open position in which the sealing side of the butterfly plate (4) is offset from the valve seat assembly (5) to allow fluid to flow, and a disassembly position in which the sealing side of the butterfly plate (4) is aligned with the outflow pipe connection part (102). When the valve stem (3) is in the disassembly position, the butterfly plate (4) can move along the center line of the valve stem (3) to leave or enter the inner cavity of the valve body middle cavity part (104); A valve seat assembly mounting groove is provided on the inner periphery of the valve seat fixing convex ring (107), and the valve seat assembly (5) is arranged in the valve seat assembly mounting groove; The valve seat assembly (5) comprises a hard-sealed valve seat (501), a four-open ring (502), and a positioning block (503); an inner wall of the valve seat assembly installation groove is provided with an embedding groove, the four-open ring (502) is arranged in the embedding groove, the hard-sealed valve seat (501) and the positioning block (503) are respectively located on both sides of the four-open ring (502) and are connected and fastened by a fourth connecting bolt (13); the hard-sealed valve seat (501) can be sealed and matched with the butterfly plate (4); A sealing groove is provided between the outer periphery of the hard sealing valve seat (501) and the inner wall of the valve seat assembly installation groove, a single sealing energy storage ring (14) is provided in the sealing groove, and a sealing end of the single sealing energy storage ring (14) is arranged away from the butterfly plate (4); The single sealed energy storage ring (14) comprises an energy storage spring made of a hairspring alloy or an INCONEL alloy, a jacket made of a high-strength alloy wire as a rib and a modified PTFE as an outer jacket, and a T-shaped retaining ring made of a high-strength alloy wire as a rib and a modified PTFE as an outer jacket, wherein an opening is provided on a side of the jacket away from the butterfly plate (4), the energy storage spring is arranged in the opening and is wrapped by the jacket to limit the position of the energy storage spring, and the T-shaped retaining ring is arranged on a side of the jacket away from the butterfly plate (4), and a small-area end thereof supports the energy storage spring; A retaining ring (15) is provided between the single sealing energy storage ring (14) and the four open rings (502), and an adjusting bolt (16) is provided, the adjusting bolt (16) sequentially passing through the positioning block (503), the four open rings (502), and the retaining ring (15), and an end portion thereof is threadedly connected to the retaining ring (15); The butterfly plate (4) comprises a butterfly plate body (401), a butterfly plate sealing ring (402), and a pressure plate (403); the butterfly plate body (401) is circumferentially provided with a first positioning groove and a second positioning groove; the first positioning groove is arranged closer to the valve stem (3) than the second positioning groove; the butterfly plate sealing ring (402) is arranged in the first positioning groove; the pressure plate (403) is arranged in the second positioning groove; the pressure plate (403) and the butterfly plate body (401) are connected and fastened by a fifth connecting bolt (17) and the butterfly plate sealing ring (402) is clamped between the two.

2. The compact online repairable ultra-low temperature butterfly valve according to claim 1 is characterized in that: The lower side of the central cavity portion (104) of the valve body is convex to form a bottom cover connecting portion (106), the outer end of the bottom cover connecting portion (106) is detachably connected to the bottom cover (8), the valve stem (3) is an integrated valve stem structure, the lower end of the valve stem (3) extends into the bottom cover connecting portion (106) and the end is detachably connected to a limited position disassembly block (7), the outer diameter of the limited position disassembly block (7) being larger than the outer diameter of the end of the valve stem (3) connected thereto; The inner cavity portion of the bottom cover connecting portion (106) is composed of, from top to bottom, a first portion which is clearance-matched with the valve stem (3), a second portion which is matched with the valve stem (3) via the valve stem bearing (19), and a third portion which is matched with the limit disassembly block (7); the inner diameter of the second portion is smaller than the outer diameter of the limit disassembly block (7), thereby limiting the limit disassembly block (7).

3. The compact online repairable ultra-low temperature butterfly valve according to claim 2 is characterized in that: The limiting disassembly block (7) is fastened to the lower end of the valve stem (3) via a second connecting bolt (10).

4. The compact online repairable ultra-low temperature butterfly valve according to claim 3 is characterized by: The bottom cover (8) and the lower end of the bottom cover connecting portion (106) are connected and fastened by a third connecting bolt (11), and a first sealing gasket (12) is provided between the bottom cover (8) and the lower end of the bottom cover connecting portion (106).

5. The compact online repairable cryogenic butterfly valve according to claim 1 is characterized by: A second sealing gasket (18) is provided between the butterfly plate sealing ring (402) and the butterfly plate body (401).

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