Double-seal valve rod

Abstract

The invention discloses a double-seal valve rod which comprises a valve rod body, an executing mechanism is arranged at the upper end of the valve rod body, an upper valve body is arranged at the bottom of the executing mechanism, the bottom of the upper valve body is connected with a lower valve body through a connecting mechanism, an upper valve seat is arranged at the bottom of the lower valve body, the upper valve seat is arranged at the top of a ball valve shell, and a valve plate is arranged in the ball valve shell. Sealing gaskets are arranged between the top and the bottom of the valve plate and the inner wall of the ball valve shell, a lower valve seat is arranged at the bottom of the ball valve shell, the valve rod body penetrates through the upper valve body, the lower valve body, the upper valve seat and the ball valve shell to be connected with the valve plate, a sealing valve sleeve is arranged in the upper valve seat at the top of the ball valve shell, and the upper end of the sealing valve sleeve extends into the upper valve body. And the sealing valve sleeve is sleeved on the valve rod body. By arranging a series of structures, bidirectional and double-layer sealing of the valve rod body is achieved, the sealing performance of the valve rod is better, execution driving of the valve rod body is achieved, and the execution reliability of the valve rod body and the execution accuracy of the valve rod are guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of valve stems, in particular to a double-sealed valve stem. Background Art

[0002] The valve stem is an important part of the valve, used for transmission, connected to the actuator or handle, and directly drives the valve core to move or rotate to achieve the opening and closing or regulating function of the valve. The main function of the valve stem is to achieve the opening and closing or regulating function of the valve. It connects the actuator or handle with the valve core, so that the operator can control the opening and closing of the valve disc and flow regulation by rotating or moving the valve stem up and down. The valve stem is usually made of copper alloy, carbon steel, stainless steel and other materials. These materials need to have sufficient strength and good impact toughness to ensure stable operation under high pressure and frequent operation. The design and manufacture of the valve stem are crucial to the performance and life of the valve.

[0003] At present, the valve stem is usually sealed by a sealing ring. The sealing performance of the sealing ring is gradually reduced due to the wear of the valve stem during rotation. The reliability of the single unidirectional sealing of the valve stem is poor. In addition, the valve stem is driven by a worm gear and a worm meshing drive. The wear of the worm and the worm gear increases the meshing distance, which affects the precise execution of the valve stem. Summary of the invention

[0004] The object of the present invention is to provide a double-sealed valve stem to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a double-sealed valve stem, comprising a valve stem body, an actuator is provided at the upper end of the valve stem body, an upper valve body is provided at the bottom of the actuator, the bottom of the upper valve body is connected to the lower valve body through a connecting mechanism, an upper valve seat is provided at the bottom of the lower valve body, the upper valve seat is arranged at the top of a ball valve housing, a valve plate is provided inside the ball valve housing, sealing gaskets are provided between the top and bottom of the valve plate and the inner wall of the ball valve housing, a lower valve seat is provided at the bottom of the ball valve housing, the valve stem body passes through the upper valve body, the lower valve body, the upper valve seat and the ball valve housing and is connected to the valve plate, a sealing valve sleeve is provided inside the upper valve seat at the top of the ball valve housing, the upper end of the sealing valve sleeve extends to the interior of the upper valve body, the sealing valve sleeve is sleeved on the valve stem body, and a sealing mechanism is provided between the valve stem body and the upper valve body above the sealing valve sleeve.

[0006] Preferably, the connecting mechanism includes a No. 1 flange, a No. 2 flange, assembly bolts, an upper groove, a lower groove, a sealing block and a sealing packing. The bottom of the upper valve body is provided with a No. 1 flange, the top of the lower valve body is provided with a No. 2 flange, the No. 1 flange and the No. 2 flange are fixed by assembly bolts, the bottom of the No. 1 flange is provided with an upper groove, the top of the No. 2 flange is provided with a lower groove, the bottom of the lower groove extends to the interior of the upper end of the upper valve body, a sealing block is provided between the lower groove and the upper groove, the sealing block is sleeved on the valve stem body, the interior of the upper valve body at the bottom of the lower groove is provided with a sealing packing, and the sealing block is pressed down on the top of the sealing packing.

[0007] Preferably, the lower end of the sealing block is arranged in a circular ring structure, the upper end of the sealing block is arranged in an inclined surface structure corresponding to the lower groove, and the middle part of the sealing block is arranged in an inclined surface structure corresponding to the upper groove.

[0008] Preferably, the sealing mechanism includes a sealing ring, an airbag and an inflation tube, a No. 1 sealing groove is provided on the valve stem body above the sealing valve sleeve, a No. 2 sealing groove is provided on the lower valve body outside the No. 1 sealing groove, a sealing ring is provided in the No. 1 sealing groove, the sealing ring is sleeved on the valve stem body, an airbag is provided inside the No. 2 sealing groove, an inflation tube is provided on one side of the airbag, the inflation tube passes through the lower valve body and is provided at the inflation port, a cap is provided on the inflation port, and the airbag is connected to the sealing ring.

[0009] Preferably, the airbag is arranged in an annular structure, a pressure sensor is arranged inside the airbag, an output end of the pressure sensor is electrically connected to a control panel, and the control panel is arranged on one side of the upper valve body.

[0010] Preferably, the actuator includes an actuator box No. 1, an actuator box No. 2, an assembly mechanism, a worm gear, a worm and a servo motor, an actuator box No. 1 is provided on the top of the upper valve body, an actuator box No. 2 is provided on one side of the actuator box No. 1, the actuator box No. 1 and the actuator box No. 2 are connected by an assembly mechanism, the sides of the actuator box No. 1 and the actuator box No. 2 that are close to each other are both opened, one end of the actuator box No. 1 close to the actuator box No. 2 is arranged inside the actuator box No. 2 through an opening, a worm gear is coaxially provided on the valve stem body inside the actuator box No. 1, a worm is provided inside the actuator box No. 2, the worm and the worm gear are meshingly arranged, a servo motor is provided on one side of the actuator box No. 2, and the output end of the servo motor is connected to one end of the worm through a coupling.

[0011] Preferably, the assembly mechanism includes an assembly plate No. 1, an assembly plate No. 2 and an assembly screw. The top and bottom of the No. 1 execution box close to one end of the No. 2 execution box are provided with an assembly plate No. 1, and the top and bottom of the No. 2 execution box away from one end of the No. 1 execution box are provided with an assembly plate No. 2. An assembly screw is threadedly provided between the No. 1 assembly plate and the No. 2 assembly plate, and a nut is provided on the assembly screw.

[0012] Preferably, the lower valve body and the upper valve seat are integrally formed, and the sealing valve sleeve is arranged in an L-shaped structure.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The double-sealed valve stem realizes double-layer sealing of the valve stem body through the sealing valve sleeve arranged inside the upper valve seat and the lower valve body, and the sealing mechanism arranged between the valve stem body and the lower valve body. The airbag and the sealing ring cooperate, and the sealing ring can reliably seal the valve stem body through the inflation of the airbag.

[0015] 2. The double-sealed valve stem realizes bidirectional sealing of the valve stem body through the No. 1 flange on the upper valve body and the No. 2 flange on the lower valve body, the upper and lower grooves cooperate with the sealing block, and the sealing packing arranged inside the lower valve body, combined with the double-layer sealing of the valve stem body. The bidirectional and double-layer sealing makes the valve stem more sealed.

[0016] 3. The double-sealed valve stem is assembled by an actuator box No. 1 and an actuator box No. 2 through an assembly mechanism through an actuator mechanism arranged on the valve stem body. The worm wheel on the valve stem body in the No. 1 actuator box cooperates with the worm in the No. 2 actuator box to realize the execution drive of the valve stem body. The position of the No. 2 actuator box on the No. 1 actuator box is adjusted by the assembly screw, that is, the spacing between the worm and the worm wheel on the valve stem body is adjusted to ensure the reliability of the execution of the valve stem body and the accuracy of the valve stem execution. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0018] Figure 2 It is a schematic diagram of the structure of the sealing valve sleeve in the present invention;

[0019] Figure 3 It is a structural schematic diagram of flange No. 1 in the present invention;

[0020] Figure 4 It is a structural schematic diagram of the No. 2 flange in the present invention;

[0021] Figure 5 It is a schematic diagram of the structure of the sealing block in the present invention;

[0022] Figure 6 It is a schematic diagram of the structure of the worm gear in the present invention.

[0023] In the figure: 1. valve stem body; 2. actuator; 21. actuator box No. 1; 22. actuator box No. 2; 23. assembly mechanism; 231. assembly plate No. 1; 232. assembly plate No. 2; 233. assembly screw; 24. worm gear; 25. worm; 26. servo motor; 3. upper valve body; 4. lower valve body; 5. upper valve seat; 6. sealing mechanism; 61. sealing ring; 62. air bag; 63. inflation tube; 7. sealing valve sleeve; 8. valve plate; 81. sealing gasket; 9. ball valve housing; 10. lower valve seat; 11. flange No. 1; 12. flange No. 2; 13. assembly bolts; 14. upper groove; 15. lower groove; 16. sealing block; 17. sealing packing. DETAILED DESCRIPTION

[0024] 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.

[0025] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0026] like Figures 1 to 6As shown, the double-sealed valve stem of this embodiment includes a valve stem body 1, an actuator 2 is provided at the upper end of the valve stem body 1, an upper valve body 3 is provided at the bottom of the actuator 2, the bottom of the upper valve body 3 is connected to the lower valve body 4 through a connecting mechanism, an upper valve seat 5 is provided at the bottom of the lower valve body 4, the upper valve seat 5 is provided at the top of the ball valve housing 9, a valve plate 8 is provided inside the ball valve housing 9, sealing gaskets 81 are provided between the top and bottom of the valve plate 8 and the inner wall of the ball valve housing 9, a lower valve seat 10 is provided at the bottom of the ball valve housing 9, and the valve stem body 1 passes through the upper valve body 3 and the lower valve body 4. The upper valve seat 5 and the ball valve housing 9 are connected to the valve plate 8. A sealing valve sleeve 7 is provided inside the upper valve seat 5 on the top of the ball valve housing 9. The sealing valve sleeve 7 adopts a high-strength rubber ring. The upper end of the sealing valve sleeve 7 extends to the interior of the upper valve body 3. The sealing valve sleeve 7 is sleeved on the valve stem body 1. A sealing mechanism 6 is provided between the valve stem body 1 and the upper valve body 3 above the sealing valve sleeve 7 to achieve two-way and double-layer sealing of the valve stem body 1, so that the valve stem has better sealing performance, realizes the execution drive of the valve stem body 1, ensures the reliability of the execution of the valve stem body 1, and the precise execution of the valve stem.

[0027] Specifically, the connection mechanism includes a No. 1 flange 11, a No. 2 flange 12, assembly bolts 13, an upper groove 14, a lower groove 15, a sealing block 16 and a sealing packing 17. The bottom of the upper valve body 3 is provided with a No. 1 flange 11, the top of the lower valve body 4 is provided with a No. 2 flange 12, the No. 1 flange 11 and the No. 2 flange 12 are fixed by assembly bolts 13, the bottom of the No. 1 flange 11 is provided with an upper groove 14, the top of the No. 2 flange 12 is provided with a lower groove 15, the bottom of the lower groove 15 extends inside the upper end of the upper valve body 3, and a sealing block 16 is provided between the lower groove 15 and the upper groove 14. The sealing block 16 adopts a high-strength sealing rubber ring. The sealing block 16 is sleeved on the valve stem body 1. A sealing packing 17 is provided inside the upper valve body 3 at the bottom of the lower groove 15. The sealing block 16 is pressed down on the top of the sealing packing 17. The sealing block 16 is clamped between the lower groove 15 and the upper groove 14. The No. 1 flange 11 and the No. 2 flange 12 are fixed by assembling bolts 13. The sealing block 16 is pressed down on the sealing packing 17 to fix the upper valve body 3 and the lower valve body 4. The sealing block 16 and the sealing packing 17 seal the valve stem body 1 at the assembly point of the upper valve body 3 and the lower valve body 4.

[0028] Furthermore, the lower end of the sealing block 16 is arranged in a circular ring structure, the upper end of the sealing block 16 is arranged in an inclined surface structure corresponding to the lower groove 14, and the middle part of the sealing block 16 is arranged in an inclined surface structure corresponding to the upper groove 15. The sealing block 16 is compactly and firmly clamped between the lower groove 15 and the upper groove 14, and the inclined surface increases the sealing contact area.

[0029] Furthermore, the sealing mechanism 6 includes a sealing ring 61, an airbag 62 and an inflation tube 63. A sealing groove No. 1 is provided on the valve stem body 1 above the sealing valve sleeve 7, a sealing groove No. 2 is provided on the lower valve body 4 outside the sealing groove No. 1, a sealing ring 61 is provided in the sealing groove No. 1, and the sealing ring 61 is made of a highly wear-resistant sealing rubber ring. The sealing ring 61 is sleeved on the valve stem body 1, an airbag 62 is provided inside the sealing groove No. 2, an inflation tube 63 is provided on one side of the airbag 62, the inflation tube 63 passes through the lower valve body 4 and is arranged at the inflation port, a cap is provided on the inflation port, the airbag 62 is connected to the sealing ring 61, the cap is removed, the existing inflation device is connected to the inflation port, and air is inflated into the airbag 62 through the inflation port. The inflation of the airbag 62 can compensate for the wear of the sealing ring 61, so that the sealing ring 61 can reliably seal the valve stem body 1.

[0030] Furthermore, the airbag 62 is arranged in an annular structure, and a pressure sensor is arranged inside the airbag 62. The output end of the pressure sensor is electrically connected to the control panel. The control panel is arranged on one side of the upper valve body 3. The pressure sensor detects the sealing performance of the sealing ring 61 to the valve stem body 1. After the sealing ring 61 is worn, the expansion space of the airbag 62 increases, and the pressure sensor detects the pressure change and inflates the airbag 62 according to the pressure data.

[0031] Furthermore, the actuator 2 includes an actuator box No. 1 21, an actuator box No. 2 22, an assembly mechanism 23, a worm gear 24, a worm 25 and a servo motor 26. The top of the upper valve body 3 is provided with an actuator box No. 1 21, and one side of the actuator box No. 1 21 is provided with an actuator box No. 2 22. The actuator box No. 1 21 and the actuator box No. 2 22 are connected by the assembly mechanism 23. The sides of the actuator box No. 1 21 and the actuator box No. 2 22 that are close to each other are both opened. The end of the actuator box No. 1 21 close to the actuator box No. 2 22 is provided inside the actuator box No. 2 22 through an opening. The valve stem body 1 inside the actuator box No. 1 21 is coaxially provided with a worm gear 24. A worm 25 is provided inside the No. 2 actuator box 22, and the worm 25 and the worm wheel 24 are meshed. A servo motor 26 is provided on one side of the No. 2 actuator box 22, and the output end of the servo motor 26 is connected to one end of the worm 25 through a coupling. The servo motor 26 on the No. 2 actuator box 22 drives the worm 25 to rotate, and the rotation of the worm 25 drives the worm wheel 24 meshed with it to rotate in the No. 1 actuator box 21. The rotation of the worm wheel 24 drives the valve stem body 1 to rotate in the No. 1 actuator box 21, the upper valve body 3, the lower valve body 4 and the upper valve seat 5, and drives the valve plate 8 to rotate inside the ball valve housing 9, thereby realizing the execution drive of the valve stem body 1.

[0032] Furthermore, the assembly mechanism 23 includes an assembly plate No. 1 231, an assembly plate No. 2 232 and an assembly screw 233. The top and bottom of the No. 1 execution box 21 close to one end of the No. 2 execution box 22 are both provided with an assembly plate No. 1 231, and the top and bottom of the No. 2 execution box 22 away from one end of the No. 1 execution box 21 are both provided with an assembly plate No. 2 232. An assembly screw 233 is threadedly arranged between the No. 1 assembly plate 231 and the No. 2 assembly plate 232, and a nut is arranged on the assembly screw 233. By turning the assembly screw 233 threadedly arranged on the No. 1 assembly plate 231 and the No. 2 assembly plate 232, the position of the No. 2 execution box 22 on the No. 1 execution box 21 is adjusted by the assembly screw 233, that is, the spacing of the meshing of the worm 25 and the worm wheel 24 on the valve stem body 1 is adjusted by the assembly mechanism 23.

[0033] Furthermore, the lower valve body 4 and the upper valve seat 5 are integrally formed, and the sealing valve sleeve 7 is arranged in an L-shaped structure, which is convenient for manufacturing.

[0034] The method of using the present embodiment is as follows: the sealing pressing block 16 is clamped between the lower clamping groove 15 and the upper clamping groove 14, the No. 1 flange 11 and the No. 2 flange 12 are fixed by the assembly bolts 13, the sealing pressing block 16 is pressed down on the sealing packing 17, the upper valve body 3 and the lower valve body 4 are fixed, the sealing pressing block 16 and the sealing packing 17 seal the valve stem body 1 at the assembly of the upper valve body 3 and the lower valve body 4, and the air is inflated into the airbag 62 through the inflation port through the inflation tube 63, and the airbag 62 expands and squeezes the sealing ring 6 1. The sealing ring 61 seals the valve stem body 1. The sealing valve sleeve 7 arranged inside the upper valve seat 5 and the lower valve body 4 cooperates with the sealing ring 61 to achieve double-layer sealing of the valve stem body 1. The airbag 62 cooperates with the sealing ring 61. The airbag 62 is inflated to compensate for the wear of the sealing ring 61, so that the sealing ring 61 can reliably seal the valve stem body 1. Therefore, the bidirectional and double-layer sealing of the valve stem body 1 is achieved by the provided sealing valve sleeve 7, the sealing ring 61, the sealing packing 17 and the sealing pressing block 16. , so that the valve stem has better sealing performance, the servo motor 26 on the second execution box 22 drives the worm 25 to rotate, and the rotation of the worm 25 drives the worm wheel 24 meshing with it to rotate in the first execution box 21, and the rotation of the worm wheel 24 drives the valve stem body 1 to rotate in the first execution box 21, the upper valve body 3, the lower valve body 4 and the upper valve seat 5, and drives the valve plate 8 to rotate inside the ball valve housing 9, so as to realize the execution drive of the valve stem body 1. Since the end of the first execution box 21 close to the second execution box 22 passes through The opening is arranged inside the No. 2 execution box 22. The assembly screw 233 threadedly arranged on the No. 1 assembly plate 231 and the No. 2 assembly plate 232 is turned. The position of the No. 2 execution box 22 on the No. 1 execution box 21 is adjusted by the assembly screw 233. That is, the meshing distance between the worm 25 and the worm wheel 24 on the valve stem body 1 is adjusted by the assembly mechanism 23 to avoid excessive meshing wear distance between the worm wheel 24 and the worm 25 due to long-term use of the valve stem body 1, thereby ensuring the reliability of the execution of the valve stem body 1 and the precise execution of the valve stem.

[0035] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A double-sealed valve stem, comprising a valve stem body (1), characterized in that: The upper end of the valve stem body (1) is provided with an actuator (2), the bottom of the actuator (2) is provided with an upper valve body (3), the bottom of the upper valve body (3) is connected to the lower valve body (4) via a connecting mechanism, the bottom of the lower valve body (4) is provided with an upper valve seat (5), the upper valve seat (5) is arranged on the top of the ball valve housing (9), the inside of the ball valve housing (9) is provided with a valve plate (8), the top and bottom of the valve plate (8) and the inner wall of the ball valve housing (9) are both provided with sealing gaskets (81), the ball valve housing (9) ) is provided with a lower valve seat (10) at the bottom, the valve stem body (1) passes through the upper valve body (3), the lower valve body (4), the upper valve seat (5) and the ball valve housing (9) and is connected to the valve plate (8), a sealing valve sleeve (7) is provided inside the upper valve seat (5) at the top of the ball valve housing (9), the upper end of the sealing valve sleeve (7) extends to the interior of the upper valve body (3), the sealing valve sleeve (7) is sleeved on the valve stem body (1), and a sealing mechanism (6) is provided between the valve stem body (1) and the upper valve body (3) above the sealing valve sleeve (7).

2. The double-sealed valve stem according to claim 1, characterized in that: The connection mechanism comprises a No. 1 flange (11), a No. 2 flange (12), assembly bolts (13), an upper groove (14), a lower groove (15), a sealing block (16) and a sealing packing (17). The bottom of the upper valve body (3) is provided with a No. 1 flange (11), the top of the lower valve body (4) is provided with a No. 2 flange (12), the No. 1 flange (11) and the No. 2 flange (12) are fixed by assembly bolts (13), and the bottom of the No. 1 flange (11) is provided with an upper groove. (14), a lower groove (15) is provided at the top of the No. 2 flange (12), the bottom of the lower groove (15) is extended and arranged inside the upper end of the upper valve body (3), a sealing block (16) is provided between the lower groove (15) and the upper groove (14), the sealing block (16) is sleeved on the valve stem body (1), a sealing packing (17) is provided inside the upper valve body (3) at the bottom of the lower groove (15), and the sealing block (16) is pressed down on the top of the sealing packing (17).

3. The double-sealed valve stem according to claim 2, characterized in that: The lower end of the sealing pressure block (16) is arranged in a circular ring structure, the upper end of the sealing pressure block (16) is arranged in an inclined surface structure corresponding to the lower clamping groove (14), and the middle part of the sealing pressure block (16) is arranged in an inclined surface structure corresponding to the upper clamping groove (15).

4. The double-sealed valve stem according to claim 1, characterized in that: The sealing mechanism (6) comprises a sealing ring (61), an air bag (62) and an inflation tube (63); a No. 1 sealing groove is provided on the valve stem body (1) above the sealing valve sleeve (7); a No. 2 sealing groove is provided on the lower valve body (4) outside the No. 1 sealing groove; a sealing ring (61) is provided in the No. 1 sealing groove; the sealing ring (61) is sleeved on the valve stem body (1); an air bag (62) is provided inside the No. 2 sealing groove; an inflation tube (63) is provided on one side of the air bag (62); the inflation tube (63) passes through the lower valve body (4) and is provided at the inflation port; a cover cap is provided on the inflation port; the air bag (62) and the sealing ring (61) are connected.

5. The double-sealed valve stem according to claim 4, characterized in that: The airbag (62) is arranged in a ring-shaped structure. A pressure sensor is arranged inside the airbag (62). The output end of the pressure sensor is electrically connected to a control panel. The control panel is arranged on one side of the upper valve body (3).

6. The double-sealed valve stem according to claim 1, characterized in that: The actuator (2) comprises a first actuator box (21), a second actuator box (22), an assembly mechanism (23), a worm wheel (24), a worm (25) and a servo motor (26); the top of the upper valve body (3) is provided with a first actuator box (21); one side of the first actuator box (21) is provided with a second actuator box (22); the first actuator box (21) and the second actuator box (22) are connected via the assembly mechanism (23); the first actuator box (21) and the second actuator box (22) are both open on the sides close to each other. The first actuator box (21) is arranged such that one end of the first actuator box (21) close to the second actuator box (22) is arranged inside the second actuator box (22) through an opening, a worm gear (24) is coaxially arranged on the valve stem body (1) inside the first actuator box (21), a worm (25) is arranged inside the second actuator box (22), and the worm (25) and the worm gear (24) are meshed with each other, a servo motor (26) is arranged on one side of the second actuator box (22), and the output end of the servo motor (26) is connected to one end of the worm gear (25) through a coupling.

7. The double-sealed valve stem according to claim 6, characterized in that: The assembly mechanism (23) comprises an assembly plate No. 1 (231), an assembly plate No. 2 (232) and an assembly screw (233); the top and bottom of the No. 1 execution box (21) close to the No. 2 execution box (22) are both provided with an assembly plate No. 1 (231); the top and bottom of the No. 2 execution box (22) away from the No. 1 execution box (21) are both provided with an assembly plate No. 2 (232); an assembly screw (233) is threadedly provided between the No. 1 assembly plate (231) and the No. 2 assembly plate (232); and a nut is provided on the assembly screw (233).

8. The double-sealed valve stem according to claim 1, characterized in that: The lower valve body (4) and the upper valve seat (5) are integrally formed, and the sealing valve sleeve (7) is arranged in an L-shaped structure.

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