Top-mounted metal hard sealing butterfly valve

Abstract

The invention discloses a top-mounted metal hard sealing butterfly valve which comprises a valve body, a valve seat, a butterfly plate, a valve rod and a driving assembly, the valve rod is of a cross-shaped structure, the valve rod and the butterfly plate are of an integrally-formed structure, a sealing piece is arranged on the side, away from the valve rod, of the butterfly plate, and a cross-shaped first channel is formed in the inner side of the valve rod. After the valve rod drives the butterfly plate to rotate by 90 degrees, the control switch controls the first electric control valve to be opened, hydraulic oil is led into the first channel and the second channel, the telescopic rod is smoothly pushed to drive the sealing piece to be matched with the valve seat, and therefore the valve can be closed; the hydraulic oil in the first channel and the second channel flows out, the telescopic rod drives the sealing piece to reset under the action of the first spring, and then the valve rod and the butterfly plate are rotated, so that the relative abrasion of the sealing piece and the valve seat can be reduced, and the service life of the valve seat is prolonged.

Description

Technical Field

[0001] The invention discloses a top-mounted metal hard-sealed butterfly valve, belonging to the technical field of valves. Background Art

[0002] A butterfly valve, also called a flap valve, is a simple regulating valve that can be used for the on-off control of low-pressure pipeline media. A butterfly valve is a valve whose closing member (valve disc or butterfly plate) is a disc that rotates around the valve shaft to achieve opening and closing. The butterfly valve mainly plays a cutting and throttling role in the pipeline. The sealing of existing butterfly valves is basically achieved by the cooperation between the butterfly plate and the valve body. Especially in the hard sealing structure, due to the large wear of the butterfly plate and the valve body during rotation, the butterfly plate is prone to failure in the use environment with high fluid pressure, resulting in the need to frequently replace the butterfly plate, thereby increasing the maintenance frequency and maintenance cost. Summary of the invention

[0003] The purpose of the present invention is to solve the problems in the prior art and to provide a top-mounted metal hard-sealed butterfly valve.

[0004] The present invention achieves the above-mentioned purpose through the following technical scheme: a top-mounted metal hard-sealed butterfly valve, comprising a valve body, a valve seat, a butterfly plate, a valve stem and a drive assembly, the valve stem is a cross-shaped structure, and it and the butterfly plate adopt an integrally formed structure, a sealing member is arranged on the side of the butterfly plate away from the valve stem, a cross-shaped first channel is arranged on the inner side of the valve stem, a plurality of second channels are arranged on the inner sides of the butterfly plate and the valve stem, the first channel and the second channel are connected, and the second channel is perpendicular to the first channel, a telescopic rod is arranged in the second channel, one end of the telescopic rod is slidably arranged in the second channel, and the other end passes through the butterfly plate, the sealing member is fixed to the telescopic rod by bolts, a plug for sealing the second channel is arranged on the valve stem, and the One end of the plug is provided with a limit column for limiting the sliding distance of the telescopic rod, and a first spring is sleeved on the outer side of the telescopic rod, and the first spring applies a force to the telescopic rod to approach the limit column. A valve seat is fixedly installed in the valve body, and the sealing member cooperates with the valve seat through a conical surface. A valve cover is provided on the valve body, and a mounting seat is provided on the valve cover. One end of the valve stem is rotatably connected to the valve body, and the other end extends into the mounting seat after passing through the valve cover. The driving assembly is provided on the mounting seat, and a transmission member is connected between the driving assembly and the valve stem. A liquid inlet pipe is provided at the end of the valve stem away from the transmission member, and the liquid inlet pipe is a T-shaped structure, and the middle part of the liquid inlet pipe is connected to the first channel, and the first electrically controlled valve and the second electrically controlled valve are provided on the liquid inlet pipe.

[0005] Preferably, the driving assembly includes a handwheel, a worm gear, a worm, a transmission shaft and a housing, the handwheel is fixedly connected to the worm gear, the worm gear is rotatably connected to the housing, one end of the transmission shaft is fixedly connected to the worm gear, and the other end of the transmission shaft passes through the housing, the transmission member includes a threaded sleeve, a fixing sleeve, a limiting bolt and a limiting sleeve, the fixing sleeve is fixedly connected to the valve stem by a bolt, one end of the transmission shaft is rotatably connected to the fixing sleeve, a plurality of limiting bolts are provided, and one end of the limiting bolt is threadedly connected to the fixing sleeve after passing through the threaded sleeve, the threaded sleeve is threadedly connected to the middle part of the transmission shaft, and the threaded sleeve is provided with two lugs, the limiting sleeve is coaxially arranged with the threaded sleeve, and the limiting sleeve is provided with a first slide groove and a second slide groove for sliding the lug, the first slide groove is a circular arc structure, and the central angle of the circle is 90°, the second slide groove is a vertical slide groove, and the second slide groove is communicated with one end of the first slide groove, the limiting sleeve is provided with a control switch at a position corresponding to the second slide groove, and the limiting sleeve is fixedly connected to the mounting seat by bolts.

[0006] Preferably, the control switch includes a concave seat, a movable rod, a conductive sheet, a first terminal, a second terminal and a second spring. The movable rod is in a T-shaped structure, and its middle portion slides through the concave seat and the limit sleeve. The second spring exerts a force on the movable rod to extend into the second slide groove. The conductive sheet is fixed on the movable rod, and convex columns are provided on both sides of the conductive sheet. Two of the first terminal and the second terminal are provided, and are respectively fixed on the upper and lower sides of the corresponding conductive sheet of the concave seat. The first terminal and the second terminal are respectively coupled to a delay circuit, and the delay circuit is used to control the first electrically controlled valve or the second electrically controlled valve to open, and close after a preset time.

[0007] Preferably, a fixing ring is provided in the valve body, the fixing ring comprises four arc blocks with a central angle of 90°, the outer diameter of the fixing ring is larger than the diameter of the valve body fluid flow, and two symmetrical arc blocks are fixedly connected to the valve seat by bolts.

[0008] Preferably, each of the arc blocks is provided with a toggle groove, and a positioning groove is provided on one of the arc blocks connected to the valve body, the valve body has an extension portion near the butterfly plate, a positioning plane is provided on the extension portion, a positioning block is installed in the positioning plane, one end of the positioning block cooperates with the positioning groove, and a threaded hole is provided on the positioning block, a positioning plane is provided on the extension portion, and a conical platform cooperating with the positioning plane is provided on the valve cover.

[0009] Preferably, a recessed groove is provided on the valve cover at a mounting position corresponding to the valve stem, the recessed groove is filled with sealing filler, and a compression sleeve is provided between the valve cover and the mounting seat to compact the sealing filler.

[0010] Compared with the prior art, the present invention has the following beneficial effects: By arranging a seal, a telescopic rod, a first spring, a first channel, a second channel, a liquid inlet pipe and a control switch, when the valve is closed, the valve stem drives the butterfly plate to rotate 90 degrees first, and then hydraulic oil of a certain pressure is introduced into the first channel and the second channel, so that the telescopic rod drives the seal to cooperate with the valve seat. When the valve is closed, the hydraulic oil in the first channel and the second channel is discharged first, so that the telescopic rod drives the seal to reset under the action of the first spring, and then the valve stem and the butterfly plate are rotated. Such a design can reduce the relative wear of the seal and the valve seat, thereby increasing the service life of the hard-sealed valve and reducing the maintenance frequency and maintenance cost.

[0011] By setting a fixing ring and a positioning block, the fixing ring is composed of four arc blocks, which is embedded in the valve body during installation and fixedly connected to the valve seat by bolts. When the valve is in a closed state, the valve seat will not move. The positioning block cooperates with one of the arc blocks, making the installation of the fixing block and the valve seat easier and more secure.

[0012] Since the butterfly plate and the seal are detachable, and the diameter of the butterfly plate is smaller than the open diameter of the valve cover installation, after the seal fails, the valve cover, butterfly plate and seal are taken out as a whole, and then disassembled and replaced with a new seal, so the overall disassembly and maintenance are convenient and simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a partial three-dimensional structural schematic diagram of a top-loading metal hard-sealed butterfly valve of the present invention; Figure 2 This is a schematic diagram of the internal structure of a top-loading metal hard-sealed butterfly valve of the present invention; Figure 3 A half-section view of the valve stem, butterfly plate, and seal in the present invention; Figure 4 An exploded view of the valve seat, butterfly plate, and seal in the present invention; Figure 5 for Figure 2 A partial enlarged view of the middle A; Figure 6 for Figure 4 A partial enlarged view of point B in the middle; Figure 7 Schematic diagram of the internal structure of the valve stem and butterfly plate in the present invention; Figure 8 It is a schematic diagram of the structure of the transmission shaft, transmission member and valve stem in the present invention; Fig. 9 It is a schematic diagram of the structure of the transmission shaft, threaded sleeve, fixed sleeve and valve stem in the present invention; Fig.10 It is a structural schematic diagram of the limiting sleeve in the present invention; Fig.11 It is a structural schematic diagram of the control switch in the present invention; Fig.12 It is a structural schematic diagram of the valve body in the present invention; Figure numerals: 1, valve body; 2, mounting seat; 3, transmission shaft; 4, valve cover; 5, first electric control valve; 6, liquid inlet pipe; 7, second electric control valve; 8, sealing member; 9, valve seat; 10, valve stem; 11, telescopic rod; 12, plug; 13, butterfly plate; 14, first channel; 15, fixing ring; 16, first spring; 17, second channel; 18, arc block; 19, extension; 20, positioning block; 21, threaded hole; 22, positioning groove; 23, toggle slot; 24, limiting column; 25, threaded sleeve; 26, first slide slot; 27, limiting bolt; 28, lug; 29, limiting sleeve; 30, second slide slot; 31, control switch; 32, fixing sleeve; 33, positioning plane; 34, concave seat; 35, second spring; 36, first terminal; 37, convex column; 38, movable rod; 39, second terminal; 40, conductive sheet; 41, pressing sleeve; 42, driving assembly; 43, transmission member; 44, conical table. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0015] like Figure 1-Figure 12As shown, a top-mounted metal hard-sealed butterfly valve includes a valve body 1, a valve seat 9, a butterfly plate 13, a valve stem 10 and a drive assembly 42. The valve stem 10 is a cross-shaped structure, and it and the butterfly plate 13 are integrally formed. A sealing member 8 is provided on the side of the butterfly plate 13 away from the valve stem 10. A cross-shaped first channel 14 is provided on the inner side of the valve stem 10. A plurality of second channels 17 are provided on the inner sides of the butterfly plate 13 and the valve stem 10. The first channel 14 is connected to the second channel 17, and the second channel 17 is perpendicular to the first channel 14. A telescopic rod 11 is provided in the second channel 17. One end of the telescopic rod 11 is slidably provided in the second channel 17, and the other end passes through the butterfly plate 13. The sealing member 8 is fixed to the telescopic rod 11 by bolts. A plug 12 for sealing the second channel 17 is provided on the valve stem 10. The plug 12 One end of the valve stem 10 is provided with a limit column 24 for limiting the sliding distance of the telescopic rod 11, and the outer side of the telescopic rod 11 is sleeved with a first spring 16, and the first spring 16 applies a force on the telescopic rod 11 to approach the limit column 24. A valve seat 9 is fixedly installed in the valve body 1, and the sealing member 8 cooperates with the valve seat 9 through a conical surface. A valve cover 4 is provided on the valve body 1, and a mounting seat 2 is provided on the valve cover 4. One end of the valve stem 10 is rotatably connected to the valve body 1, and the other end extends into the mounting seat 2 after passing through the valve cover 4. The driving component 42 is provided on the mounting seat 2, and a transmission member 43 is connected between the driving component 42 and the valve stem 10. A liquid inlet pipe 6 is provided at one end of the valve stem 10 away from the transmission member 43. The liquid inlet pipe 6 is a T-shaped structure, and the middle part of the liquid inlet pipe 6 is connected to the first channel 14, and the first electric-controlled valve 5 and the second electric-controlled valve 7 are provided on the liquid inlet pipe 6.

[0016] The driving assembly 42 includes a handwheel, a worm gear, a worm, a transmission shaft 3 and a housing. The handwheel is fixedly connected to the worm gear, the worm gear is rotatably connected to the housing, one end of the transmission shaft 3 is fixedly connected to the worm gear, and the other end of the transmission shaft 3 passes through the housing. The transmission member 43 includes a threaded sleeve 25, a fixed sleeve 32, a limit bolt 27 and a limit sleeve 29. The fixed sleeve 32 is fixedly connected to the valve stem 10 by bolts. One end of the transmission shaft 3 is rotatably connected to the fixed sleeve 32. There are multiple limit bolts 27, and one end of the limit bolt 27 is threadedly connected to the fixed sleeve 32 after passing through the threaded sleeve 25. The threaded sleeve 25 is threadedly connected to the middle part of the transmission shaft 3, and two lugs 28 are provided on the threaded sleeve 25. The limit sleeve 29 is coaxially arranged with the threaded sleeve 25, and the limit sleeve 29 is provided with a first slide groove 26 and a second slide groove 30 for sliding the lug 28. The first slide groove 26 is a circular arc structure with a central angle of 90°, and the second slide groove 30 is a vertical slide. When the transmission shaft 3 is rotated, the threaded sleeve 25 can drive the threaded sleeve 25 to rotate synchronously in one direction until the lug 28 is blocked by the limit sleeve 29 and cannot continue to rotate. At this time, the lug 28 is located above the second slide groove 30. In this process, the threaded sleeve 25 can rely on a plurality of limit bolts 27 to drive the fixed sleeve 32 and the valve stem 10 to rotate synchronously, so that the butterfly plate 13 and the sealing member 8 rotate 90°. When the transmission shaft 3 continues to rotate, since the threaded sleeve 25 cannot continue to rotate, the threaded sleeve 25 can only rely on the cooperation of the lug 28 and the second slide groove 30 to slide vertically, so that preparations can be made for controlling the operation of the first electric control valve 5 or the second electric control valve 7.

[0017] The control switch 31 includes a concave seat 34, a movable rod 38, a conductive sheet 40, a first terminal 36, a second terminal 39 and a second spring 35. The movable rod 38 is a T-shaped structure, and the middle part thereof slides through the concave seat 34 and the limit sleeve 29. The second spring 35 exerts a force on the movable rod 38 to extend into the second slide groove 30. The conductive sheet 40 is fixed on the movable rod 38, and bosses 37 are provided on both sides of the conductive sheet 40. There are two first terminals 36 and two second terminals 39, which are respectively fixed on the upper and lower sides of the concave seat 34 corresponding to the conductive sheet 40. The first terminal 36 and the second terminal 39 are respectively coupled to a delay circuit, which is used to control the first electric control valve 5 or the second electric control valve 7 to open and close after a preset time. One end of the movable rod 38 is located in the second slide groove 30. When the lug 28 on the threaded sleeve 25 slides in the second slide groove 30, the lug 28 exerts downward pressure on the movable rod 38, and the conductive sheet 40 can allow the two first terminals 3 6 is connected so that one of the delay circuits is energized, and the first electric control valve 5 is opened, so that hydraulic oil is passed into the first channel 14 and the second channel 17. When the lug 28 slides upward in the second slide groove 30, the movable rod 38, under the action of the second spring 35, makes the conductive sheet 40 communicate with the two second terminals 39, and energizes another delay circuit, so that the second electric control valve 7 is opened, so that the hydraulic oil in the first channel 14 and the second channel 17 is discharged, and the limit column 24 is located on the plug 12. When the telescopic rod 11 is out of contact with the limit column 24, the area of ​​the hydraulic oil acting on the telescopic rod 11 increases, so that the hydraulic oil in the first channel 14 and the second channel 17 can maintain the sealing of the sealing member 8 and the valve seat 9 with a smaller pressure when the valve is closed. In order to better control the passing pressure, a pressure sensor can be provided to detect the fluid pressure at the inflow end in real time, so as to control the pressure of the hydraulic oil passing into the first channel 14 and the second channel 17.

[0018] A fixing ring 15 is arranged in the valve body 1, and the fixing ring 15 includes four arc blocks 18 with a central angle of 90°. The outer diameter of the fixing ring 15 is larger than the diameter of the fluid flowing in the valve body 1, and two symmetrical arc blocks 18 are fixedly connected to the valve seat 9 by bolts, and each arc block 18 is provided with a toggle groove 23, and one of the arc blocks 18 connected to the valve body 1 is provided with a positioning groove 22. The valve body 1 has an extension portion 19 at a position close to the butterfly plate 13, and a positioning plane 33 is provided on the extension portion 19. A positioning block 20 is installed in the positioning plane 33, and one end of the positioning block 20 cooperates with the positioning groove 22, and a threaded hole 21 is provided on the positioning block 20, and a positioning plane 33 is provided on the extension portion 19. A conical platform 44 cooperating with the positioning plane 33 is provided on the valve cover 4. When installing the valve seat 9, first place the four arc blocks 18 according to the positioning plane 33. First install it in the valve body 1, and then adjust the position of the fixing ring 15 by toggling the groove 23, so that two of the arc blocks 18 are aligned with the bolt mounting holes on the valve seat 9, then insert the positioning block 20 into the valve body 1, and let one end of the positioning block 20 be embedded in the positioning groove 22 of one of the arc blocks 18, so that the fixing ring 15 cannot continue to rotate, thereby achieving the positioning effect, and then connect the valve seat 9 to the fixing ring 15 by bolts, so that the fixing ring 15 and the valve seat 9 will not fall off when subjected to the force of the fluid, and the installation is quite firm. When the valve cover 4 and the valve body 1 are fixed by bolts, the conical platform 44 will press the positioning block 20, so that the positioning block 20 cannot be removed from the valve body 1, and the threaded hole 21 can rely on the bolts to more conveniently pull the positioning block 20 out of the valve body 1.

[0019] A recessed groove is provided on the valve cover 4 at the installation position corresponding to the valve stem 10, and the recessed groove is filled with sealing filler. A pressing sleeve 41 is provided between the valve cover 4 and the mounting seat 2 to compact the sealing filler. During assembly, the mounting seat 2 and the valve cover 4 are fixed by bolts, so that the pressing sleeve 41 is subjected to the pressure of the mounting seat 2 to compact the sealing filler, thereby ensuring that no fluid leakage occurs between the valve stem 10 and the valve cover 4.

[0020] Working principle: When the valve is open, the pressure of the hydraulic oil in the first channel 14 and the second channel 17 is very small. The telescopic rod 11 drives the seal 8 to contact the butterfly plate 13 under the action of the first spring 16, and the lug 28 on the threaded sleeve 25 is located in the first slide groove 26. When the valve needs to be closed, the transmission shaft 3 is rotated by turning the hand wheel. Since the threaded sleeve 25 is located in the first slide groove 26, its rotation is not blocked, so that the threaded sleeve 25 keeps rotating synchronously with the transmission shaft 3. At this time, the threaded sleeve 25 relies on the limit bolt 27 to drive the fixed sleeve 32 and the valve stem 10 to rotate synchronously, so that after the butterfly plate 13 drives the seal 8 to rotate 90°, the seal 8 and the valve seat 9 are kept. When the lug 28 is pressed onto the movable rod 38, the movable rod 38 compresses the second spring 35 downward, and the boss 37 on the conductive sheet 40 is in conflict with the first terminal 36, so that one of the delay circuits is energized and the first electrically controlled valve 5 is controlled to be open for a certain period of time, so that the first channel 14 and the second channel 17 are closed after a certain pressure of hydraulic oil is introduced, so that the telescopic rod 11 drives the sealing member 8 to contact and cooperate with the valve seat 9 to close the valve.

[0021] When the valve needs to be opened, the hand wheel is rotated in the opposite direction. Since the lug 28 is located in the second slide groove 30 at this time, when the transmission shaft 3 rotates in the opposite direction, the threaded sleeve 25 can only slide upward, so that the second spring 35 drives the movable rod 38 to move upward and allows the conductive sheet 40 to disengage from the first terminal 36. Until the conductive sheet 40 conflicts with the second terminal 39, another delay circuit is energized and controls the second electric control valve 7 to open for a certain period of time, so that the hydraulic oil in the first channel 14 and the second channel 17 is discharged, and the telescopic rod 11 retracts into the second channel 17 under the action of the second spring 35, so that the sealing member 8 is separated from the valve seat 9. Subsequently, when the lug 28 slides out of the second slide groove 30, since the freedom of the threaded sleeve 25 to rotate in the opposite direction is no longer restricted, it can rotate synchronously with the transmission shaft 3, so that the threaded sleeve 25 relies on the limit bolt 27 to drive the fixed sleeve 32 and the valve stem 10 to rotate 90° in the opposite direction, so that the butterfly plate 13 and the sealing member 8 rotate synchronously and the valve is fully opened.

[0022] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0023] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A top-entry metal hard-sealed butterfly valve, comprising a valve body (1), a valve seat (9), a butterfly plate (13), a valve stem (10) and a drive assembly (42), characterized in that: The valve stem (10) is a cross-shaped structure, and it and the butterfly plate (13) adopt an integrally formed structure. A sealing member (8) is provided on the side of the butterfly plate (13) away from the valve stem (10). A cross-shaped first channel (14) is provided on the inner side of the valve stem (10). A plurality of second channels (17) are provided on the inner sides of the butterfly plate (13) and the valve stem (10). The first channel (14) and the second channel (17) are communicated with each other, and the second channel (17) is perpendicular to the first channel (14). A telescopic rod (11) is provided in the second channel (17). One end of the telescopic rod (11) is slidably arranged in the second channel (17), and the other end is arranged through the butterfly plate (13). The sealing member (8) is fixed to the telescopic rod (11) by bolts. A plug (12) for sealing the second channel (17) is provided on the valve stem (10). One end of the plug (12) has a limit column (24) for limiting the sliding distance of the telescopic rod (11). A first spring (16) is sleeved on the outer side of the telescopic rod (11), and the first spring (16) applies a force to the telescopic rod (11) to approach the limit column (24). A valve seat (9) is fixedly installed in the valve body (1), and the sealing member (8) cooperates with the valve seat (9) through a conical surface. A valve cover (4) is arranged on the valve body (1), and a mounting seat (2) is arranged on the valve cover (4). One end of the valve stem (10) is rotatably connected to the valve body (1), and the other end passes through the valve cover ( 4) and then extends into the mounting seat (2), the driving assembly (42) being arranged on the mounting seat (2), and a transmission member (43) being connected between the driving assembly (42) and the valve stem (10), and a liquid inlet pipe (6) being arranged at one end of the valve stem (10) away from the transmission member (43), the liquid inlet pipe (6) being of a T-shaped structure, and the middle portion of the liquid inlet pipe (6) being in communication with the first channel (14), and a first electrically controlled valve (5) and a second electrically controlled valve (7) being arranged on the liquid inlet pipe (6).

2. A top entry metal hard seal butterfly valve according to claim 1, characterized in that: The driving assembly (42) comprises a hand wheel, a worm gear, a worm, a transmission shaft (3) and a housing; the hand wheel is fixedly connected to the worm gear, the worm gear is rotatably connected to the housing, one end of the transmission shaft (3) is fixedly connected to the worm gear, and the other end of the transmission shaft (3) is arranged to pass through the housing; the transmission member (43) comprises a threaded sleeve (25), a fixed sleeve (32), a limiting bolt (27) and a limiting sleeve (29); the fixed sleeve (32) is fixedly connected to the valve stem (10) by means of bolts; one end of the transmission shaft (3) is rotatably connected to the fixed sleeve (32); a plurality of limiting bolts (27) are provided, and one end of the limiting bolt (27) passes through the threaded sleeve (25) and is threadably connected to the fixed sleeve (32). The threaded sleeve (25) is threadedly connected to the middle part of the transmission shaft (3), and two lugs (28) are arranged on the threaded sleeve (25). The limiting sleeve (29) is coaxially arranged with the threaded sleeve (25), and a first slide groove (26) and a second slide groove (30) are arranged on the limiting sleeve (29) for the lugs (28) to slide. The first slide groove (26) is an arc-shaped structure with a central angle of 90°. The second slide groove (30) is a vertical slide groove, and the second slide groove (30) is connected to one end of the first slide groove (26). The limiting sleeve (29) is provided with a control switch (31) at a position corresponding to the second slide groove (30), and the limiting sleeve (29) is fixedly connected to the mounting seat (2) by bolts.

3. A top entry metal hard seal butterfly valve according to claim 2, characterized in that: The control switch (31) comprises a concave seat (34), a movable rod (38), a conductive sheet (40), a first terminal (36), a second terminal (39) and a second spring (35). The movable rod (38) is in a T-shaped structure, and its middle portion slides through the concave seat (34) and the limit sleeve (29). The second spring (35) exerts a force on the movable rod (38) to extend into the second slide groove (30). The conductive sheet (40) is fixed on the movable rod (38), and both sides of the conductive sheet (40) are provided with convex columns (37). Two first terminals (36) and two second terminals (39) are provided, and are respectively fixed on the upper and lower sides of the concave seat (34) corresponding to the conductive sheet (40). The first terminals (36) and the second terminals (39) are respectively coupled to a delay circuit, and the delay circuit is used to control the first electrically controlled valve (5) or the second electrically controlled valve (7) to open and close after a preset time.

4. A top entry metal hard seal butterfly valve according to claim 1, characterized in that: A fixing ring (15) is arranged inside the valve body (1), and the fixing ring (15) comprises four arc-shaped blocks (18) with a central angle of 90°. The outer diameter of the fixing ring (15) is larger than the diameter of the fluid flowing through the valve body (1), and two symmetrical arc-shaped blocks (18) are fixedly connected to the valve seat (9) by bolts.

5. A top entry metal hard seal butterfly valve according to claim 4, characterized in that: Each of the arc blocks (18) is provided with a toggle groove (23), and one of the arc blocks (18) connected to the valve body (1) is provided with a positioning groove (22); the valve body (1) has an extension portion (19) at a position close to the butterfly plate (13); a positioning plane (33) is provided on the extension portion (19); a positioning block (20) is installed in the positioning plane (33); one end of the positioning block (20) cooperates with the positioning groove (22), and a threaded hole (21) is provided on the positioning block (20); a positioning plane (33) is provided on the extension portion (19), and a conical platform (44) cooperating with the positioning plane (33) is provided on the valve cover (4).

6. A top entry metal hard seal butterfly valve according to claim 3, characterized in that: A recessed groove is provided on the valve cover (4) at a mounting position corresponding to the valve stem (10), the recessed groove is filled with sealing filler, and a compression sleeve (41) is provided between the valve cover (4) and the mounting seat (2) for compacting the sealing filler.

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