Valve rod lifting device

Abstract

The utility model discloses a valve rod lifting device which comprises a shell, a lifting assembly, a pressing assembly and a transmission assembly. By arranging the lifting assembly, the valve rod is driven by the lifting assembly to move to forcibly open the valve; specifically, the lifting assembly comprises a lifting rod and a connecting component, the connecting component is arranged on the lifting rod and used for being connected with a valve rod of the valve, when the lifting rod moves, the valve rod connected with the connecting component can be driven to move, and the design has the advantages that only the length of the valve rod needs to be increased, and a fixing connector is reserved in the valve rod of the valve; the original structure of the valve or the actuator does not need to be changed, the existing valve in use does not need to be greatly changed, the actuator of the existing valve does not need to be disassembled, interference to existing equipment and potential shutdown risks are reduced to the maximum extent, and the flexibility and efficiency of maintenance and emergency treatment are remarkably improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to valve technical field especially relates to a valve rod lifting device. BACKGROUND

[0002] In the design and application of straight stroke electric valve, such as common electric gate valve and globe valve, its operating mechanism depends on the precise thread interaction between valve rod nut and valve rod to drive the gate or valve disc to complete the opening and closing action. However, as a key transmission component, the valve rod nut is often damaged due to thread wear caused by long-time operation, and once it fails, it will directly cause the idling phenomenon of the actuator, and then the valve loses the control function and cannot open and close the valve.

[0003] Especially in the operation and maintenance practice of photo-thermal power station, the valve rod nut wear of the steam-water side valve can be maintained by replacement and repair to maintain system operation, but for the key valve on the molten salt side, such as the heat absorber valve, once the nut cannot be opened due to wear, it will directly cause the molten salt to freeze and block inside the heat absorber, causing major operation interruption and economic loss. Therefore, it is particularly urgent to develop an efficient and adaptable valve rod emergency lifting solution to ensure that the valve control ability can be quickly restored in an emergency. SUMMARY

[0004] In view of the problems in the background art, the utility model aims to provide a valve rod lifting device, which comprises a shell, a lifting assembly, a pressing assembly and a transmission assembly.

[0005] The first end of the valve rod away from the valve is the first end.

[0006] The lifting assembly is arranged in the shell, and the lifting assembly is configured to be connected to the first end of the valve rod at one end, so that the movement of the lifting assembly drives the valve rod to move along the axial direction of the valve rod.

[0007] The pressing assembly is configured to provide driving force for the movement of the lifting assembly by pressing or pulling.

[0008] The transmission assembly is arranged in the shell, and the transmission assembly is configured to transmit the driving force generated by the pressing assembly to the lifting assembly.

[0009] The power input end of the transmission assembly is connected to the pressing assembly, and the power output end of the transmission assembly is connected to the lifting assembly.

[0010] As a preferred embodiment, the pressing assembly comprises a pressing rod and a first member, and the first member is configured to transmit the driving force of pressing or pulling the pressing rod to the power input end of the transmission assembly.

[0011] The compression rod has an execution end at one axial end for inputting driving force, and has a fulcrum end at the other axial end, and the fulcrum end of the compression rod is arranged on the shell or the fulcrum end of the compression rod is arranged on the power input end of the transmission assembly.

[0012] Preferably, the transmission assembly comprises an input shaft, the first component comprises a ratchet wheel and a driving pawl, the ratchet wheel is arranged on the input shaft, and the driving pawl is arranged on the compression rod.

[0013] When the execution end of the compression rod moves in a preset direction, the driving pawl drives the ratchet wheel to rotate.

[0014] Preferably, the transmission assembly further comprises a locking mechanism arranged on the shell, and the locking mechanism is configured to lock the position of the lifting assembly.

[0015] Preferably, the locking mechanism is a brake pawl matched with the ratchet wheel to limit reverse rotation of the input shaft, so as to prevent the valve rod from moving towards the valve.

[0016] Preferably, the lifting assembly comprises a lifting rod and a connecting component.

[0017] The connecting component is detachably arranged at one axial end of the lifting rod, or the connecting component is fixedly arranged at one axial end of the lifting rod.

[0018] The connecting component is configured to be connected with the first end of the valve rod.

[0019] Preferably, a connecting threaded hole is arranged on the side of the connecting component facing the valve rod, and the connecting component is threadedly connected with the first end of the valve rod.

[0020] Preferably, the transmission assembly comprises the input shaft, an input gear and a rack structure.

[0021] The input shaft is rotatably arranged in the shell, and the input gear is arranged on the input shaft.

[0022] The rack structure is detachably arranged on one side of the lifting assembly, or the rack structure is fixedly arranged on one side of the lifting assembly.

[0023] The input gear is engaged with the rack structure.

[0024] Preferably, the transmission assembly further comprises an output shaft, a transmission gear and an output gear.

[0025] The output shaft is rotatably arranged in the shell, the transmission gear is arranged on the output shaft, and the output gear is arranged on the output shaft.

[0026] The output gear is engaged with the rack structure, and the transmission gear is engaged with the input gear.

[0027] As preferred, a lengthening structure is further included;

[0028] The lengthening structure is detachably arranged on the first end of the valve rod, or the lengthening structure is fixedly arranged on the first end of the valve rod.

[0029] The lengthening structure is configured to be connected with the lifting assembly.

[0030] The utility model discloses a valve rod lifting device, which has the following advantages and positive effects compared with the prior art:

[0031] 1. The valve rod lifting device in the utility model has a lifting assembly arranged to move the valve rod to forcibly open the valve. Specifically, the lifting assembly includes a lifting rod and a connecting member arranged on the lifting rod. The connecting member is used to connect the valve rod. When the lifting rod moves, the valve rod connected with the connecting member also moves. This design has the advantage that only the length of the valve rod needs to be increased, and a fixed interface is left on the valve rod. Therefore, the original structure of the valve or the actuator does not need to be changed, and the existing valve does not need to be greatly modified. Moreover, the actuator of the existing valve does not need to be removed, which minimizes the interference with the existing equipment and the potential risk of shutdown, and significantly improves the flexibility and efficiency of maintenance and emergency treatment.

[0032] 2. The valve rod lifting device in the utility model has a pressure rod. The driving force input by the execution end is amplified by the lever principle and then transmitted to the transmission assembly. According to the lever principle, the longer the force arm, the more obvious the effect of force. Through the above arrangement, the large-diameter valve rod can be easily lifted and the valve can be easily opened.

[0033] 3. The valve rod lifting device in the utility model does not use hydraulic driving members and electric driving members, thereby realizing compact and lightweight structure. It is not only convenient to carry and move, but also greatly widens the application scenarios. Especially when facing special valve positions with limited installation space, the traditional valve rod lifting device driven by a hydraulic pump or a motor is often difficult to use due to its large size. However, the design overcomes this limitation and can be easily implemented in a small space, ensuring efficient application and operational flexibility in various complex conditions, and significantly improving the practicality and emergency handling capacity.

[0034] 4. The valve rod lifting device in the utility model divides the connecting member into the moving part and the detachable connecting member, and the connecting member is used for connecting the valve rod, so that the device can adapt to various specifications of valves, and only the adaptive connecting member needs to be replaced when facing different specifications of valves. BRIEF DESCRIPTION OF DRAWINGS

[0035] The specific embodiments of the utility model will be further described in detail below in combination with the drawings, wherein:

[0036] Fig. 1 The utility model discloses a valve installation schematic diagram;

[0037] Fig. 2 The utility model discloses a front view cross section;

[0038] Fig. 3 The utility model discloses a side view cross section;

[0039] Fig. 4 The utility model discloses a top view.

[0040] Mark explanation:

[0041] 1, valve rod lifting device;11, shell;111, base;112, first shaft sleeve;113, second shaft sleeve;12, lifting rod;121, rack structure;122, limiting flange;123, connecting member;131, pressing rod;132, ratchet wheel;133, drive pawl;134, brake pawl;141, input shaft;142, input gear;143, transmission gear;144, output shaft;145, output gear;2, actuator;3, valve;31, valve rod. DETAILED DESCRIPTION

[0042] The utility model will be further described in detail below in combination with the drawings and specific embodiments. According to the following description, the advantages and characteristics of the utility model will be more clear. It should be noted that the drawings are all very simplified and all use non-precise ratios, only to facilitate, clear and assist the purpose of explaining the embodiment of the utility model.

[0043] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the utility model are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), if the certain posture changes, the directional indication also changes accordingly.

[0044] EMBODIMENT

[0045] Referring to the drawings Figs. 1 to 4The utility model discloses a valve rod lifting device for the forced lifting of valve rod 31 after the failure of valve rod 31 nut, and is suitable for the opening and closing of valve 3 after the failure of valve rod 31 nut of straight stroke valve 3 such as stop valve and gate valve.

[0046] The valve rod lifting device 1 comprises a shell 11, a lifting assembly, a pressing assembly and a transmission assembly.

[0047] During work, the shell 11 is arranged on the fixed part of the valve 3, and the fixed part is the actuator 2 in the embodiment. The actuator 2 is used for controlling the movement of the valve rod 31. The shell 11 comprises a base 111 close to one end of the valve 3. The shell 11 is arranged on the actuator 2 through the base 111. Of course, in other cases, the actuator 2 can be removed to make the valve rod lifting device more convenient to connect with the valve rod 31. This can be flexibly adapted according to the specific situation.

[0048] The lifting assembly and the transmission assembly are both arranged in the shell 11. One end of the valve rod 31 away from the valve 3 is the first end. The lifting assembly is configured to be connected with the first end of the valve rod 31, so as to drive the valve rod 31 to move along the axial direction of the valve rod 31 through the movement of the lifting assembly. The transmission assembly is configured to transmit the driving force generated by the pressing assembly to the lifting assembly, that is, the lifting assembly is connected with the pressing assembly through the transmission assembly. The pressing assembly is configured to provide the driving force for the movement of the lifting assembly through pressing or pulling.

[0049] Specifically, in the embodiment, referring to the accompanying drawings, Figs. 1-3The shell 11 is in the shape of a cuboid as a whole, and the interior of the shell 11 is provided with a cavity for mounting a transmission assembly and a lifting assembly, while a pressing assembly is mounted on the exterior of the shell 11. The pressing assembly provides driving for the transmission assembly in a pressing or pulling manner, and the transmission assembly transmits the driving force generated by the pressing assembly to the lifting assembly, so as to ensure that the lifting assembly can move the valve rod 31 (generally, one end of the valve rod 31 is provided with a valve flap, and the other end of the valve rod 31 is provided with a thread) in the axial direction of the valve rod 31, thereby completing the opening or closing of the valve 3. In a specific embodiment, the lifting assembly includes a lifting rod 12 and a connecting member 123, which is detachably arranged at one end of the lifting rod 12 in the axial direction, or is fixedly arranged at one end of the lifting rod 12 in the axial direction. The connecting member 123 is provided with a connecting threaded hole on the side facing the valve rod 31. The end of the valve rod 31 away from the valve 3 is the first end (i.e., the end of the valve rod 31 provided with a thread), and the first end of the valve rod 31 is provided with an external thread. The connecting member 123 is screwed with the first end of the valve rod 31 to realize the connection between the connecting member 123 and the first end of the valve rod 31. Of course, in other embodiments, the valve rod 31 and the lifting connecting member 123 can be connected without screwing, such as through clamping or friction connection, and the specific design can be made according to the actual working condition, as long as the movement of the lifting assembly can drive the valve rod 31 to move in the axial direction of the valve rod 31. The structure of the shell 11 can also be designed according to the specific condition.

[0050] The detachable design of the connecting member 123 makes it more adaptable, and different models of connecting members 123 can be used to adapt to different models of valve rods 31, so that it can adapt to various specifications of valves 3. When facing different specifications of valves 3, only the appropriate connecting member 123 needs to be replaced.

[0051] Referring to the accompanying drawings Figs. 1 to 4 In the embodiment, the end of the shell 11 facing the valve rod 31 is provided with an insertion hole, and the valve rod 31 enters the interior of the shell 11 through the insertion hole and is connected with the connecting member 123. Further, the insertion hole is provided with a first shaft sleeve 112, and the valve rod 31 is arranged in and slidably connected to the first shaft sleeve 112, and the first shaft sleeve 112 is used to limit the movement direction of the valve rod 31. The end of the shell 11 away from the valve rod 31 is provided with a through hole, and the through hole is provided with a second shaft sleeve 113. The end of the lifting rod 12 away from the valve rod 31 is arranged in and slidably connected to the second shaft sleeve 113, and the second shaft sleeve 113 is used to limit the movement direction of the lifting rod 12. The lifting rod 12 extends out of the shell 11 away from the valve rod 31, and the part of the lifting rod 12 extending out of the shell 11 is provided with a limiting portion, which is used to limit the lifting rod 12 and prevent the lifting rod 12 from moving excessively towards the valve 3. In the embodiment, the limiting portion is a limiting flange 122.

[0052] In the embodiment, the pressing assembly comprises a pressing rod 131 and a first component, the first component is configured to transmit the driving force of pressing the pressing rod 131 or pulling the pressing rod 131 to the power input end of the transmission assembly;

[0053] The axial one end of the pressing rod 131 is an execution end for driving force input, and the axial other end of the pressing rod 131 is a fulcrum end, the fulcrum end of the pressing rod 131 is arranged on the shell 11, or the fulcrum end of the pressing rod 131 is arranged on the power input end of the transmission assembly.

[0054] Specifically, referring to the accompanying drawings Fig. 2 The pressing assembly comprises a pressing rod 131 and a first component, the first component is arranged between the execution end and the fulcrum end of the pressing rod 131 and close to the fulcrum end, so that when the pressing rod 131 swings relative to the fulcrum end, the driving force is transmitted to the transmission assembly through the first component. In the embodiment, the transmission assembly comprises an input shaft 141, the input end of the transmission assembly is the input shaft 141, and the first component comprises a ratchet wheel 132 and a driving pawl 133, the input shaft 141 is rotatably installed in the shell 11, one end of the input shaft 141 extends to the outside of the shell 11 through the inner wall of the shell 11, the ratchet wheel 132 is arranged outside the shell 11 and installed on the section of the input shaft 141 extending out of the shell 11, and the driving pawl 133 is installed between the execution end and the fulcrum end of the pressing rod 131 and close to the fulcrum end to form a cooperation with the ratchet wheel 132, so that the driving pawl 133 can drive the ratchet wheel 132 to rotate by pressing the execution end of the pressing rod 131, and then drive the input shaft 141 to rotate. Generally, the driving pawl 133 is rotatably installed on the pressing rod 131, and such design makes the driving pawl 133 push the ratchet wheel 132 to rotate when pressing the execution end of the pressing rod 131, and the ratchet wheel 132 will not rotate when pulling the execution end of the pressing rod 131, so that the input shaft 141 can be driven to rotate in a predetermined direction by reciprocating pressing the execution end of the pressing rod 131. Generally, the pressing rod 131 is also rotatably installed on the outside of the shell 11, and in another embodiment, the pressing rod 131 can also be rotatably installed on the input shaft 141. The pressing rod 131 specifically transmits the driving force input by the execution end to the transmission assembly after amplification by the lever principle. As known from the lever principle, the longer the force arm, the more obvious the effect of force. By designing the pressing rod 131 to a suitable length and cooperating with the foregoing arrangement, the effect of manually lifting the large-diameter valve rod 31 and opening the valve 3 can be achieved.

[0055] Of course, in other embodiments, the first component can also be a fixed part of the pressure rod 131, capable of fixing the pressure rod 131 on the end of the input shaft 141 extending out of the shell 11, or the first component is a hydraulic component or a pneumatic component, and the actuating end of the pressure rod 131 can press the hydraulic oil or gas to drive the movement of the lifting assembly. Here, no limitation is made; the specific first component can be designed according to different use environments, as long as the driving force is input to the input shaft 141 when the actuating end of the pressure rod 131 is pressed or pulled. Of course, in a specific embodiment, the input end of the transmission assembly can also not be the input shaft 141, and the specific design can be made according to the working condition.

[0056] Further, the pressure assembly further comprises a locking mechanism, which is arranged on the shell 11 and is configured to lock the position of the lifting assembly.

[0057] Specifically, referring to the accompanying drawings Fig. 2 In the embodiment, the locking mechanism is a brake pawl 134, which cooperates with the ratchet wheel 132 to limit the reverse rotation of the input shaft 141, so as to prevent the valve rod 31 from moving towards the valve 3. The brake pawl 134 is rotationally connected to the shell 11, and a spring is arranged between the brake pawl 134 and the shell 11, which gives the brake pawl 134 an elastic force to rotate towards the ratchet wheel 132. When it is needed to reset the lifting rod 12, the brake pawl 134 is simply pried away from the ratchet wheel 132. Of course, in other embodiments, the locking mechanism can also be a lock disc and a fixed pin. Specifically, a locking hole is formed in the shell 11, and the lock disc is a disc installed on the input shaft 141. A plurality of insertion holes are arranged on the lock disc along the circumferential direction of the input shaft 141. The locking method is to insert the fixed pin between the locking hole and the insertion hole corresponding to the locking hole at this time, so as to lock the input shaft 141 through the fixed pin, thereby locking the position of the lifting assembly at this time. This locking method is only one of many locking methods; and the specific locking method can be designed according to the actual working condition, as long as the locking mechanism can lock the position of the lifting assembly at this time after the pressure rod 131 is loosened. Preferably, the locking mechanism is the brake pawl 134 and the ratchet wheel 132 in the embodiment.

[0058] In the embodiment, the transmission assembly comprises an input shaft 141, an input gear 142 and a rack structure 121. The input shaft 141 is rotationally arranged in the shell 11, and the input gear 142 is arranged on the input shaft 141. The rack structure 121 is detachably arranged on one side of the lifting rod 12, or the rack structure 121 is fixedly arranged on one side of the lifting rod 12. The input gear 142 is engaged with the rack structure 121. When the input shaft 141 rotates, the lifting rod 12 is driven to move through the transmission of the input gear 142 and the rack structure 121.

[0059] Further, the transmission assembly further comprises an output shaft 144, a transmission gear 143 and an output gear 145, the output shaft 144 is rotatably arranged in the housing 11, the transmission gear 143 is arranged on the output shaft 144, and the output gear 145 is arranged on the output shaft 144; the output gear 145 is engaged with the rack structure 121, and the transmission gear 143 is engaged with the input gear 142. When the input shaft 141 rotates, the transmission is sequentially driven through the input gear 142, the transmission gear 143, the output gear 145 and the rack structure 121 to move the lifting rod 12.

[0060] Preferably, the lifting assembly as a whole presents a prismatic structure, which can prevent the lifting rod 12 of the lifting assembly from rotating and disengaging from the output gear 145 during movement.

[0061] Of course, in other embodiments, the transmission assembly can not use gear rotation, and the specific design can be made according to the actual working condition; and the overall structure of the lifting assembly can not present a prismatic structure, for example, it can present a cylindrical, regular column or irregular column shape, etc., as long as it can meet the driving force output by the transmission assembly to drive the valve rod 31 to move.

[0062] In the present embodiment, a lengthening structure is further included, which is detachably arranged on the first end of the valve rod 31, or is fixedly arranged on the first end of the valve rod 31; the lengthening structure is configured to be connectable with the connecting member 123.

[0063] Specifically, generally, the lengthening structure is integrated with the valve rod 31, that is, in actual situation, the valve rod 31 is designed to be lengthened when the valve 3 is manufactured (the lengthened valve rod is referred to as a lengthening structure valve rod, which is used to distinguish the aforementioned valve rod 31), and the side of the lengthening structure valve rod away from the valve 3 is still connected with the connecting member 123 through threads (the thread connection between the lengthening structure valve rod and the connecting member 123 is that the thread hole is arranged on the lengthening structure valve rod, and the external thread is arranged on the connecting member 123, or the thread hole is arranged on the connecting member 123, and the external thread is arranged on the lengthening structure valve rod), which has the advantage of not needing to change the original structure of the valve 3 or the actuator 2, without the need to make large changes to the existing valve 3 in use, without the need to remove the actuator 2 of the existing valve 3 in use, which maximally reduces the interference to the existing equipment and the potential risk of shutdown, and significantly improves the flexibility and efficiency of maintenance and emergency treatment; of course, in other embodiments, for the existing valve 3, a detachable lengthening structure can be added, one end of which is connectable with the first end of the valve rod, and the other end is connectable with the connecting member 123, and the specific arrangement of the lengthening structure can be designed according to the actual working condition.

[0064] Of course, the lengthening structure and the connection mode between the connecting member 123 or the valve rod 31 are not limited to the threaded connection mode, but can also be connected in a clamping mode or a friction connection mode, etc.

[0065] The working process of the utility model will be further described below:

[0066] After the maintenance personnel find that the valve rod 31 nut is invalid, the device is sleeved on the valve rod 31 extending from the actuator 2, the outer thread at the top of the valve rod 31 is connected with the inner thread at the bottom of the connecting member 123 of the device, the base 111 at the bottom of the shell 11 is placed on the shell 11 of the actuator 2, and then the pressing rod 131 is pressed downward, the driving pawl 133 on the pressing rod 131 cooperates with the ratchet wheel 132 to drive the input shaft 141 to rotate counterclockwise, thereby driving the input gear 142 to rotate, the input gear 142 drives the transmission gear 143, the output shaft 144, and the output gear 145 to rotate, and the output gear 145 drives the lifting rod 12 to move upward through the rack structure 121 to lift the valve rod 31, and the valve 3 is opened.

[0067] The utility model discloses a valve rod 31 connected with the valve 3 through the lifting assembly, which can drive the valve rod 31 to move to forcibly open the valve 3, only needs to leave a fixed interface on the valve rod 31 of the valve 3, does not need to change the original structure of the valve 3 or the actuator 2, does not need to make great changes to the existing valve 3 in use, only needs to increase the length of the valve rod 31, and does not need to remove the actuator 2 of the existing valve 3 when using the utility model. And because the pressing rod 131, the two-stage gear meshing and the gear rack meshing transmission assembly are arranged in the device, the length of the pressing rod 131 and the gear meshing ratio can be changed to achieve the purpose of saving labor, according to the lever principle, the longer the force arm is, the more obvious the effect of force is, and the above-mentioned device can achieve the effect of easily lifting the valve rod of a large-diameter valve and opening the valve by manpower.

[0068] The utility model discloses abandoning the use of hydraulic first component and electric first component, thereby realizing the compactness and light weight of the structure, not only convenient for carrying and moving, but also greatly widening the applicable scenarios. Especially when facing special valve positions with limited installation space, the traditional valve rod lifting device with hydraulic or electric drive is often difficult to use due to its large size, but the design overcomes this limitation and can be easily implemented in a small space, ensuring efficient application and flexible operation in various complex working conditions, significantly improving the practicality and emergency handling capacity.

[0069] The embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the above embodiments. Even if various changes are made to the present application, provided that the changes fall within the scope of the present application claims and equivalent technologies thereof, they still fall within the scope of the present application.

Claims

1. A valve stem lifting device characterized by, The valve device comprises a housing, a lifting assembly, a pressing assembly and a transmission assembly; The valve rod has a first end away from the valve; The lifting assembly is arranged in the housing, and is configured to be connected to the first end of the valve rod, so that the valve rod is moved along the axial direction of the valve rod by the movement of the lifting assembly; The pressing assembly is configured to provide driving force for the movement of the lifting assembly by pressing or pulling; The transmission assembly is arranged in the housing, and is configured to transmit the driving force generated by the pressing assembly to the lifting assembly; The power input end of the transmission assembly is connected to the pressing assembly, and the power output end of the transmission assembly is connected to the lifting assembly.

2. The valve stem lifting device of claim 1, wherein, The pressing assembly comprises a pressing rod and a first member, and the first member is configured to transmit the driving force for pressing or pulling the pressing rod to the power input end of the transmission assembly; The axial one end of the pressing rod is an execution end for inputting driving force, and the axial other end of the pressing rod is a fulcrum end, which is arranged on the housing or the power input end of the transmission assembly.

3. The valve stem lifting device of claim 2, wherein, The transmission assembly comprises an input shaft, the first member comprises a ratchet wheel and a driving pawl, the ratchet wheel is arranged on the input shaft, and the driving pawl is arranged on the pressing rod; When the execution end of the pressing rod moves in a predetermined direction, the driving pawl drives the ratchet wheel to rotate.

4. The valve stem lifting device of claim 3, wherein, The pressing assembly further comprises a locking mechanism arranged on the housing, and the locking mechanism is configured to lock the position of the lifting assembly.

5. The valve stem lifting device of claim 4, wherein, The locking mechanism is a brake pawl, which cooperates with the ratchet wheel to limit the reverse rotation of the input shaft, so as to prevent the valve rod from moving towards the valve.

6. The valve stem lifting device of claim 1, wherein, The lifting assembly comprises a lifting rod and a connecting member; The connecting member is detachably arranged at the axial one end of the lifting rod, or the connecting member is fixedly arranged at the axial one end of the lifting rod; The connecting member is configured to be connected to the first end of the valve rod.

7. A valve stem lifting device according to claim 6, characterised in that The side of the connecting member facing the valve rod is provided with a connecting threaded hole, and the connecting member is threadedly connected to the first end of the valve rod.

8. The valve stem lifting device of claim 2, wherein, The transmission assembly comprises an input shaft, an input gear and a rack structure; The input shaft is rotatably arranged in the housing, and the input gear is arranged on the input shaft; The rack structure is detachably arranged on one side of the lifting assembly, or the rack structure is fixedly arranged on one side of the lifting assembly; The input gear is engaged with the rack structure.

9. The valve stem lifting device of claim 8, wherein, The transmission assembly further comprises an output shaft, a transmission gear and an output gear; The output shaft is rotatably arranged in the housing, the transmission gear is arranged on the output shaft, and the output gear is arranged on the output shaft; The lifting assembly has a prismatic structure, the output gear is engaged with the rack structure, and the transmission gear is engaged with the input gear.

10. A valve stem lifting device according to any one of claims 1 to 9, wherein The valve device further comprises an elongated structure; The elongated structure is detachably arranged on the first end of the valve rod, or the elongated structure is fixedly arranged on the first end of the valve rod. The lengthened structure is configured to be connectable with the lifting assembly. The lengthened structure is configured to be connectable with the lifting assembly.

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