Large-bore sodium valve drive

Abstract

The application provides a large-diameter sodium valve driving device, relates to the technical field of nuclear reactor control equipment, and specifically comprises a casing, a driving motor, a transmission worm, a transmission worm wheel and an output shaft. The transmission worm has a driving part and a transmission part, the driving part is in transmission connection with a driving shaft, and the transmission part is arranged at intervals with the driving part in the axial direction of the transmission worm. The transmission worm wheel has an outer edge and an inner edge, the outer edge is in meshing transmission connection with the transmission part. The output shaft is inserted into the worm wheel and in transmission connection with the inner edge, and is used for connecting the sodium valve. The driving shaft and the driving part are made of low-alloy carburizing steel containing chromium, manganese and titanium, the outer edge is made of high-tin nickel bronze, and the transmission part is made of medium-carbon alloy structural steel containing chromium. The application forms a stable transmission structure through the combination of multiple materials, can maintain stability under sodium fire high temperature, avoids transmission failure caused by thermal deformation or material degradation, and meets the emergency action requirements in the sodium leakage accident of a nuclear power plant.

Description

Technical Field

[0001] This invention relates to the field of nuclear reactor control equipment technology, and more specifically, to a large-diameter sodium valve driving device. Background Technology

[0002] A nuclear reactor is a device that controls and sustains a nuclear fission chain reaction. There are many types of nuclear reactors, but their basic components are the same: an active zone, a reflector, an outer pressure vessel, and a shielding layer. The active zone consists of nuclear fuel, a moderator, a coolant, and control rods.

[0003] In key projects of fourth-generation nuclear energy systems, liquid metallic sodium is used as the working fluid in the cooling system. Large-diameter sodium valves are core equipment controlling fluid flow in the secondary main cooling system and the steam generator accident protection system. During normal operation, the large-diameter sodium valves in the secondary main cooling system remain fully open, while those in the steam generator accident protection system remain fully closed. In the event of a sodium leak, the fully open large-diameter sodium valves will rapidly close within 20 seconds, while the fully closed large-diameter sodium valves will rapidly open within 5 seconds. This quickly cuts off the flow of sodium and allows sodium from the piping system to rapidly enter the sodium container, minimizing the hazards of the sodium leak and ensuring system operational safety and personnel safety.

[0004] Currently, the electric actuators used in large-diameter sodium valves in nuclear power plants are imported products. Domestic research and development of electric actuators for these valves is in its infancy, and the country is heavily reliant on imports. Therefore, there is an urgent need for a large-diameter sodium valve drive device that can operate in a sodium fire environment. Summary of the Invention

[0005] The purpose of this invention is to provide a large-diameter sodium valve driving device to alleviate the technical problem that existing technologies have not designed large-diameter sodium valve driving devices that operate in sodium fire environments.

[0006] This invention provides a large-diameter sodium valve driving device for driving sodium valves in nuclear reactors, comprising: a housing, a drive motor, a transmission worm gear, a transmission worm wheel, and an output shaft.

[0007] An installation space is formed inside the casing.

[0008] The drive motor has a drive shaft.

[0009] The transmission worm has a driving part and a transmission part. The driving part is connected to the driving shaft, and the transmission part and the driving part are spaced apart along the axial direction of the transmission worm.

[0010] The transmission worm gear has an outer edge and an inner edge, the outer edge of which meshes with the transmission part for transmission connection.

[0011] The output shaft is inserted into the worm gear and is drivenly connected to the inner edge. The output shaft is used to connect to the sodium valve.

[0012] The drive shaft and the drive unit are made of low-alloy carburized steel containing chromium, manganese and titanium, the outer edge is made of high-tin nickel bronze, the transmission unit is made of medium-carbon alloy structural steel containing chromium, and the transmission worm, the transmission worm wheel and the output shaft are all located in the installation space.

[0013] Furthermore, the transmission worm gear includes: a worm body, a transmission gear, and a transmission sleeve.

[0014] The worm gear body has multiple positioning components along its circumference on its side wall.

[0015] A transmission gear is located at one end of the drive shaft to form the drive unit.

[0016] The transmission sleeve is fitted onto the worm gear body to form the transmission part.

[0017] The transmission gear and the transmission sleeve are both connected to the positioning element on the worm gear body, so that the transmission gear and the transmission sleeve rotate with the worm gear body.

[0018] Furthermore, the worm gear body is a splined shaft.

[0019] Both the transmission gear and the transmission sleeve are adapted to the spline shaft.

[0020] Furthermore, both the worm gear body and the transmission part are made of 40Cr material.

[0021] Furthermore, the large-diameter sodium valve drive device also includes a handwheel and a hand-electric switch.

[0022] The handwheel is located at the end of the transmission worm gear away from the drive motor and is opposite to the transmission worm gear.

[0023] A flashlight switching device is located on one side of the transmission worm gear and is connected to the transmission worm wheel. The flashlight switching device drives the transmission worm wheel to move along its own axis to be connected to the drive motor or the handwheel.

[0024] Furthermore, the large-diameter sodium valve drive device also includes: an electrical box, a stroke controller, and a torque controller.

[0025] The electrical box is located on one side of the drive motor.

[0026] The travel controller is located inside the electrical box and is electrically connected to the drive motor.

[0027] The torque controller is located inside the electrical box and is electrically connected to the drive motor.

[0028] Furthermore, both the housing and the electrical box are provided with a fire-retardant coating.

[0029] The fire-retardant coating includes water-based intumescent fire-retardant coatings.

[0030] Furthermore, the drive shaft and the drive unit are engaged by a helical gear.

[0031] Furthermore, the drive shaft and the drive unit are made of 20CrMnTi material.

[0032] Furthermore, the outer edge is ZCuSn 12 Ni2 material.

[0033] Beneficial effects: In this invention, the drive shaft and worm gear drive unit are made of low-alloy carburized steel containing chromium, manganese, and titanium, thereby improving the tooth surface contact strength and tooth root bending fatigue strength, ensuring the reliability of the gear pair under high-speed operation and high torque output conditions, and reducing the noise of the gear pair during high-speed rotation. The transmission part of the transmission worm gear is made of chromium-containing medium-carbon alloy structural steel to enhance surface hardness and wear resistance, and the outer edge of the worm wheel is made of high-tin nickel bronze, forming a highly wear-resistant friction pair with the worm gear, effectively resisting the mechanical wear of frequent opening and closing of the sodium valve. In addition, this invention forms a stable transmission structure through the combination of multiple materials, which can maintain stability under the high temperature of sodium fire, avoiding transmission failure caused by thermal deformation or material degradation, and meeting the emergency action requirements in sodium leakage accidents in nuclear power plants. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the main structure of a large-diameter sodium valve driving device provided in an embodiment of this application; Figure 2 This is a top view of the structure of the large-diameter sodium valve driving device provided in the embodiments of this application.

[0036] icon: 100-Housing; 200-Drive motor; 210-Drive shaft; 300-Transmission worm gear; 301-Drive unit; 302-Transmission unit; 303-Transmission worm wheel; 310-Worm body; 400-Handwheel; 410-Hand-electric switch; 500-Electrical box; 510-Stroke controller; 520-Torque controller. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0040] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0041] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," not that the structure must be completely horizontal, but can be slightly tilted.

[0042] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] To facilitate understanding of this embodiment, the application scenarios and design concepts of this application embodiment will be briefly introduced below.

[0044] A nuclear reactor is a device that controls and sustains a nuclear fission chain reaction. There are many types of nuclear reactors, but their basic components are the same: an active zone, a reflector, an outer pressure vessel, and a shielding layer. The active zone consists of nuclear fuel, a moderator, a coolant, and control rods.

[0045] The 600MW demonstration fast reactor, a key project of the fourth-generation nuclear energy system, uses liquid metallic sodium as its working fluid in its cooling system. Large-diameter sodium valves are core equipment controlling fluid flow in the secondary main cooling system and the steam generator accident protection system. During normal operation, the large-diameter sodium valves in the secondary main cooling system remain fully open, while those in the steam generator accident protection system remain fully closed. The gate of the fully open large-diameter sodium valve is fully raised to the top of the valve chamber, forming a full-bore flow channel, reducing sodium flow resistance and preventing impurity deposition caused by localized eddies. The gate of the fully closed large-diameter sodium valve is tightly fitted to the valve seat, achieving zero leakage through a hard metal seal and cutting off sodium flow. In the event of a sodium leak, the fully open large-diameter sodium valve will close rapidly within 20 seconds, while the fully closed large-diameter sodium valve will open rapidly within 5 seconds, quickly cutting off the sodium medium flow and allowing the sodium medium in the pipeline system to rapidly enter the sodium container. This minimizes the hazards of sodium leakage and ensures system operational safety and personnel safety.

[0046] Therefore, nuclear power plants have very high requirements for large-diameter sodium valves. The valves must be able to open or close quickly while ensuring a sufficiently large valve stem thrust. One way to address this challenge is to use advanced valve electric actuators to ensure that the valves meet the operating requirements of nuclear power plants.

[0047] Currently, the electric actuators used in large-diameter sodium valves at nuclear power plants are imported products, and domestic research and development of such valve electric actuators is still in its infancy. Over time, the reliability of the equipment has gradually declined due to factors such as wear and tear and aging of the electric actuator components. At the same time, the number of spare parts is extremely limited, making subsequent replacement difficult. In addition, the highly unstable international situation poses a severe challenge to the safe operation and operating costs of nuclear power plants.

[0048] Therefore, this application provides a large-diameter sodium valve driving device, which, through testing and verification, can ensure the safe and reliable operation of nuclear power plants. It can reduce the construction and maintenance costs of domestic nuclear power units, improve the operational support capabilities of domestic nuclear power units, enhance the competitiveness of my country's independently developed nuclear power units in exports, promote the localization of supporting equipment technology for fourth-generation nuclear power plants, enhance China's competitiveness in the international nuclear power market, and accelerate the localization of electric actuators.

[0049] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0050] See Figure 1 , Figure 2 The large-diameter sodium valve driving device provided in this embodiment includes a housing 100, a drive motor 200, a transmission worm gear 300, a transmission worm wheel 303, and an output shaft.

[0051] In this embodiment, an installation space is formed within the housing 100. The drive motor 200 has a drive shaft 210. The transmission worm 300 has a drive portion 301 and a transmission portion 302. The drive portion 301 is driveably connected to the drive shaft 210, and the transmission portion 302 and the drive portion 301 are spaced apart along the axial direction of the transmission worm 300. The transmission worm wheel 303 has an outer edge and an inner edge. The outer edge meshes with the transmission portion 302 for drive connection. An output shaft is inserted into the worm wheel and drively connected to the inner edge. The output shaft is used to connect to a sodium valve.

[0052] Furthermore, the drive shaft 210 and drive unit 301 are made of low-alloy carburized steel containing chromium, manganese and titanium, with the outer edge made of high-tin nickel bronze. The transmission unit 302 is made of medium-carbon alloy structural steel containing chromium. The transmission worm 300, transmission worm wheel 303 and output shaft are all located within the installation space.

[0053] Specifically, in this embodiment, the drive shaft 210 and the worm drive unit 301 are made of low-alloy carburized steel containing chromium, manganese and titanium, which can significantly improve the tooth surface contact strength and tooth root bending fatigue strength, thereby ensuring the reliability of the gear pair under high-speed operation and high torque output conditions. At the same time, it can also reduce the noise generated under high-speed rotation.

[0054] In this embodiment, the transmission part 302 of the transmission worm 300 is made of chromium-containing medium carbon alloy structural steel, which can further enhance the surface hardness and wear resistance. At the same time, the outer edge of the worm wheel is made of high tin nickel bronze, which forms a high wear-resistant friction pair with the worm, effectively resisting the mechanical wear of the sodium valve due to frequent opening and closing.

[0055] Furthermore, this embodiment uses a combination of multiple materials to form a stable transmission structure, which can maintain stability under the high temperature of sodium fire, avoid transmission failure caused by thermal deformation or material degradation, and meet the emergency action requirements in sodium leakage accidents at nuclear power plants.

[0056] In this embodiment, the transmission worm 300 includes a worm body 310, a transmission gear, and a transmission sleeve.

[0057] The worm gear body 310 has multiple positioning elements on its side wall along its circumference. A transmission gear is located at one end of the drive shaft 210 to form a drive unit 301. A transmission sleeve is fitted onto the worm gear body 310 to form a transmission unit 302.

[0058] Furthermore, both the transmission gear and the transmission sleeve are connected to the positioning element on the worm body 310 so that the transmission gear and the transmission sleeve rotate with the worm body 310.

[0059] Specifically, in this embodiment, the transmission worm 300 adopts a combined structure of worm body 310, transmission gear, and transmission sleeve, and achieves rigid synchronous transmission of the three through positioning components. In this embodiment, the transmission gear (i.e., the drive part 301) is made of high-strength carburized steel with excellent fatigue resistance on the tooth surface, and the transmission sleeve (i.e., the transmission part 302) is made of wear-resistant medium carbon alloy steel to ensure the hardness of the worm transmission area. Under this structure, precise zonal reinforcement for wear resistance and impact resistance is achieved.

[0060] Furthermore, the transmission worm 300 is a separate structure consisting of the worm body 310, the transmission gear, and the transmission sleeve. When a component is damaged, the vulnerable parts can be replaced individually, resulting in lower maintenance costs. The positioning component eliminates the risk of relative displacement between the transmission gear and the transmission sleeve or the worm body 310, ensuring that power transmission does not slip under high-speed, high-torque conditions.

[0061] In this embodiment, the worm gear body 310 is a splined shaft. The transmission gear and transmission sleeve are both adapted to the splined shaft.

[0062] In this embodiment, the worm gear body 310 specifically adopts a splined shaft structure, and both the transmission gear and the transmission sleeve can achieve transmission through spline engagement. The multi-tooth meshing structure of the splined shaft doubles the torque-bearing area, thereby eliminating the risk of transmission slippage. At the same time, the circumferentially distributed tooth grooves ensure the coaxiality of the transmission gear and the transmission sleeve, thereby avoiding wear due to off-center loading.

[0063] Furthermore, the splined fit allows the transmission sleeve to freely expand and contract axially under high-temperature conditions, compensating for the thermal deformation stress generated by the high-temperature environment of sodium flammation and preventing jamming. In addition, the splined interface is a standardized interface, allowing for quick assembly and disassembly of both the transmission gear and the transmission sleeve.

[0064] Specifically, in this embodiment, both the worm gear body 310 and the transmission part 302 are made of 40Cr.

[0065] In this embodiment, both the worm gear body 310 and the transmission part 302 are made of 40Cr alloy structural steel. After quenching and tempering, the hardness of 40Cr material reaches 28-32HRC and the tensile strength is ≥980MPa. When subjected to an emergency torque of 2000N·m, the deformation is reduced by 40% (compared to ordinary carbon steel), which greatly avoids the risk of transmission shaft breakage.

[0066] Furthermore, the strength decay rate of 40Cr alloy steel in a sodium fire environment at 300℃ is less than 15% (the decay rate of ordinary 45 steel is greater than 30%), which can ensure that the worm gear does not deform or jam during rapid opening and closing in 5 seconds.

[0067] In addition, after high-frequency quenching, the 40Cr material forms a tooth surface hardness of 50-55HRC, which forms an optimal hardness ratio of 2.5:1 with the ZCuSn12Ni2 worm gear (hardness 90HB), increasing the wear life of the transmission pair to more than 2200 cycles, making it very suitable for driving large-diameter sodium valves.

[0068] In this embodiment, the large-diameter sodium valve drive device also includes a handwheel 400 and a hand-electric switch 410.

[0069] The handwheel 400 is located at the end of the transmission worm gear 300 away from the drive motor 200 and is opposite to the transmission worm gear 300. The hand-light switch 410 is located on one side of the transmission worm gear 300 and is connected to the transmission worm wheel 303. The hand-light switch 410 drives the transmission worm wheel 303 to move along its own axis to be connected to the drive motor 200 or to the handwheel 400.

[0070] Specifically, in this embodiment, after the flashlight switching component 410 is connected to the transmission worm gear 300, it can drive the transmission worm gear 300 to move along its own axial direction. In the normal state, the transmission worm gear 300 and the drive motor 200 are driven by the drive part 301 meshing with the drive shaft 210. The flashlight switching component 410 can drive the transmission worm gear 300 to move, causing the drive part 301 to move relative to the drive shaft 210. The drive part 301 disengages from the drive shaft 210, and the transmission worm gear 300 disengages from the drive motor 200.

[0071] After the transmission worm 300 moves axially and disengages from the drive motor 200, the end of the transmission worm 300 is inserted into the axle of the handwheel 400, so that the transmission worm 300 and the axle of the handwheel 400 are connected by insertion, and the large-diameter sodium valve drive device is switched to manual mode. The transmission worm 300 can be rotated by turning the handwheel 400.

[0072] In this embodiment, the large-diameter sodium valve drive device also includes an electrical box 500, a stroke controller 510, and a torque controller 520.

[0073] The electrical box 500 is located on one side of the drive motor 200. The stroke controller 510 is located inside the electrical box 500 and is electrically connected to the drive motor 200. The torque controller 520 is located inside the electrical box 500 and is electrically connected to the drive motor 200.

[0074] Specifically, in this embodiment, the stroke controller 510 and the torque controller 520 are integrated in the electrical box 500. The torque controller 520 is controlled by the timing of bypass closing or opening to avoid malfunctions caused by torque overshoot during opening and closing.

[0075] Furthermore, the travel controller 510 in this embodiment adopts a trigger structure with a wide copper strip, which enables specific switches to act in advance and generate differential signals more quickly, thereby meeting timing requirements.

[0076] In this embodiment, both the housing 100 and the electrical box 500 are provided with a fire-retardant coating. The fire-retardant coating includes a water-based intumescent fire-retardant coating.

[0077] When exposed to fire, the coating expands to form a carbonized heat insulation layer of ≥30mm (measured at 300℃), controlling the internal temperature rise of the casing to <80℃. This ensures the stable operation of electronic components (torque controller 520, stroke controller 510, etc.) and 302 transmission parts within the electrical box 500. Furthermore, the expansion layer formed by the water-based intumescent fire-retardant coating can isolate oxygen, thereby improving the efficiency of terminating the sodium combustion chain reaction.

[0078] Furthermore, in this embodiment, the housing 100 and the electrical box 500 are both made of QT400-18 ductile iron, which has good machinability, high impact toughness at room temperature, high plasticity, low brittle transition temperature, and good low-temperature toughness.

[0079] In this embodiment, the drive shaft 210 and the drive unit 301 are engaged by a helical gear.

[0080] In helical gear meshing transmission, the tooth surface contact area is higher, the single-tooth meshing overlap is higher, and the noise is lower. In this embodiment, a progressive meshing is specifically used, which can eliminate the follow-through impact force of spur gears and reduce vibration acceleration.

[0081] In this embodiment, the drive shaft 210 and the drive unit 301 are made of 20CrMnTi material.

[0082] Cr element can improve hardenability, making the hardness gradient in the root transition zone of the gear gentler and avoiding the risk of tooth breakage caused by stress concentration. After carburizing and quenching, the tooth surface hardness of 20CrMnTi carburizing steel can reach 58-62HRC, and the bending fatigue limit is ≥850MPa, which can meet the impact load brought by 2200 emergency clamping cycles.

[0083] Furthermore, 20CrMnTi carburized steel is a perfect match for the tooth profile of helical gears, which can further alleviate the contact stress on the tooth surface.

[0084] Among them, the 20CrMnTi has a 100% domestic production rate, and its material cost is 60% lower than that of imported special steels of the same type. Moreover, the energy consumption of the carburizing process is lower than that of traditional forged steel heat treatment. This can further improve the lightweight effect.

[0085] In this embodiment, the outer edge is made of ZCuSn12Ni2 material.

[0086] The ZCuSn12Ni2 high-tin nickel bronze material exhibits a stable coefficient of friction of 0.08-0.12 under sodium-fired high-temperature (300℃) conditions, with a wear rate of <0.05mg / (N·m), further improving the challenge of extending mechanical wear life. Simultaneously, it can form a golden ratio of hardness gradient with the 40Cr worm gear (50 HRC : 90 HB = 2.5:1), ensuring the worm gear pair life lock reaches 2200 emergency actions with zero failures.

[0087] It should be noted that in this embodiment, the load switch life of the drive motor 200 is at least 2200 cycles to ensure that the large-diameter sodium valve drive device provided in this embodiment can withstand various valve operating conditions.

[0088] In addition, in this embodiment, each seam of the housing 100 is provided with a seal, which is made of fluororubber, and the grease used in the transmission structure is a high-temperature resistant grease.

[0089] Under this structure, the large-diameter sodium valve driving device provided in this embodiment can meet the seismic requirements of nuclear power plants and has good high-temperature resistance characteristics, thereby ensuring that the fire generated by sodium leakage can be effectively contained in the event of a sodium leakage accident, and that the large-diameter sodium valve can be driven to operate in the event of a sodium fire accident.

[0090] Furthermore, under this structure, the output torque of the large-diameter sodium valve drive device provided in this embodiment can reach up to 2000 N·m, the output speed can reach up to 110 r / min, and the noise during operation does not exceed 80 decibels.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A large-diameter sodium valve driving device, characterized in that, The actuation of sodium valves used in nuclear reactors includes: The casing (100) has an internal installation space; A drive motor (200) has a drive shaft (210); The transmission worm (300) has a drive part (301) and a transmission part (302), the drive part (301) is connected to the drive shaft (210) for transmission, and the transmission part (302) and the drive part (301) are spaced apart along the axial direction of the transmission worm (300); The transmission worm gear (303) has an outer edge and an inner edge, the outer edge meshing with the transmission part (302) for transmission connection; An output shaft is inserted into the worm gear and drivenly connected to the inner edge; the output shaft is used to connect to the sodium valve. The drive shaft (210) and the drive unit (301) are made of low-alloy carburized steel containing chromium, manganese and titanium, the outer edge is made of high-tin nickel bronze, the transmission unit (302) is made of medium-carbon alloy structural steel containing chromium, and the transmission worm (300), the transmission worm wheel (303) and the output shaft are all located in the installation space.

2. The large-diameter sodium valve driving device according to claim 1, characterized in that, The transmission worm (300) includes: The worm gear body (310) has multiple positioning elements on its sidewalls along its circumference; A transmission gear is provided at one end of the drive shaft (210) to form the drive unit (301); A transmission sleeve is fitted onto the worm gear body (310) to form the transmission part (302); The transmission gear and the transmission sleeve are both connected to the positioning element on the worm body (310) so that the transmission gear and the transmission sleeve rotate with the worm body (310).

3. The large-diameter sodium valve driving device according to claim 2, characterized in that, The worm gear body (310) is a splined shaft; Both the transmission gear and the transmission sleeve are adapted to the spline shaft.

4. The large-diameter sodium valve driving device according to claim 2, characterized in that, The worm gear body (310) and the transmission part (302) are both made of 40Cr.

5. The large-diameter sodium valve driving device according to claim 1, characterized in that, The large-diameter sodium valve driving device also includes: A handwheel (400) is located at the end of the transmission worm (300) away from the drive motor (200) and opposite to the transmission worm (300); A flashlight switch (410) is disposed on one side of the transmission worm (300) and is connected to the transmission worm wheel (303). The flashlight switch (410) drives the transmission worm wheel (303) to move along its own axis to be connected to the drive motor (200) or to the handwheel (400).

6. The large-diameter sodium valve driving device according to claim 1, characterized in that, The large-diameter sodium valve driving device also includes: An electrical box (500) is located on one side of the drive motor (200); A stroke controller (510) is located inside the electrical box (500) and electrically connected to the drive motor (200); A torque controller (520) is located inside the electrical box (500) and electrically connected to the drive motor (200).

7. The large-diameter sodium valve driving device according to claim 6, characterized in that, Both the housing (100) and the electrical box (500) are provided with fire-retardant coatings; The fire-retardant coating includes water-based intumescent fire-retardant coatings.

8. The large-diameter sodium valve driving device according to claim 1, characterized in that, The drive shaft (210) and the drive unit (301) are engaged by a helical gear.

9. The large-diameter sodium valve driving device according to any one of claims 1-8, characterized in that, The drive shaft (210) and the drive unit (301) are made of 20CrMnTi material.

10. The large-diameter sodium valve driving device according to any one of claims 1-8, characterized in that, The outer edge is made of ZCuSn12Ni2 material.

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