Steam generator primary side manhole cover plate screw jacking installation trolley

Abstract

The application provides a screw jacking installation trolley for a manhole cover plate on a primary side of a steam generator, comprising: front directional wheels, rear universal wheels, a lower frame, an upper frame for bearing the manhole cover plate, a jacking mechanism for driving the upper frame to lift relative to the lower frame, a turnover mechanism for turning over the manhole cover plate, and a cover plate frame for fixing the manhole cover plate, the front directional wheels are arranged below the front part of the lower frame, and the rear universal wheels are arranged below the rear part of the lower frame; the upper frame is arranged above the lower frame, the jacking mechanism is connected between the lower frame and the upper frame, the turnover mechanism is arranged on the upper frame, and the cover plate frame is connected with the turnover mechanism.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plant maintenance equipment technology, and in particular to a screw-type lifting and installation trolley for the primary side manhole cover of a steam generator. Background Technology

[0002] The steam generator is a key piece of equipment in the primary loop of a nuclear power plant, serving as the "energy exchange hub" between the primary and secondary loops. During operation, the high-temperature, high-pressure cooling water from the primary loop, carrying the enormous heat generated by the nuclear reaction, flows into the inverted U-shaped heat transfer tubes inside the steam generator. The heat is then transferred through the tube walls to the feedwater in the secondary loop, heating it into saturated steam to drive the turbine generator and generate electricity.

[0003] However, the wall thickness of heat transfer tubes is generally only 1-2 mm, and corrosion will occur over time during use. To prevent radioactive leakage from the primary loop to the secondary loop due to heat transfer tube damage, the primary side manhole on the lower head of the steam generator needs to be opened periodically for eddy current inspection of the heat transfer tubes. Preventive maintenance should be carried out when the wall thickness decreases to a certain extent. Therefore, the primary side manhole cover of the steam generator needs to be opened and closed periodically according to the overhaul cycle.

[0004] Opening the manhole cover on the primary side of the steam generator is a high-radiation-risk operation during nuclear power plant overhauls, increasing the difficulty of the work. It involves direct exposure to radioactive corrosion products (CRUD) accumulated inside the equipment, with radiation primarily originating from neutron-activated CRUD. During nuclear power plant operation, CRUD in the primary coolant circuit is irradiated with neutrons and converted into radioactive nuclides, which then deposit on the inner surfaces of the primary side of the steam generator (such as water chambers and U-tubes). Studies have assessed that the radiation dose received by each worker during the entire opening and closing process is approximately 1.00-1.44 mSv.

[0005] The primary side manhole cover of a steam generator typically weighs around 500 kg, making manual disassembly and assembly difficult. Furthermore, the disassembly and assembly process requires lifting, flipping, and precise alignment with the installation position. Existing technology lacks dedicated auxiliary tools, resulting in low disassembly and assembly efficiency, difficulty in ensuring accuracy, and potential safety risks. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a screw-type lifting and installation trolley for the primary side manhole cover of a steam generator, which addresses the shortcomings of the prior art.

[0007] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A screw-type lifting and installation trolley for a primary side manhole cover of a steam generator includes: a front directional wheel, a rear universal wheel, a lower frame, an upper frame for carrying the manhole cover, a lifting mechanism for driving the upper frame to rise and fall relative to the lower frame, a flipping mechanism for flipping the manhole cover, and a cover frame for fixing the manhole cover. The front directional wheel is located below the front part of the lower frame, and the rear universal wheel is located below the rear part of the lower frame. The upper frame is located above the lower frame, the lifting mechanism is connected between the lower frame and the upper frame, the flipping mechanism is located on the upper frame, and the cover frame is connected to the flipping mechanism.

[0008] Furthermore, the lifting mechanism includes: a lead screw, a worm gear mechanism, and a lifting hand crank. The lead screw is disposed between the lower frame and the upper frame; the worm gear mechanism is disposed on the lower frame, and the worm wheel of the worm gear mechanism is drivenly connected to the lead screw; the lifting hand crank is connected to the worm gear mechanism through a transmission component.

[0009] Furthermore, there are three lead screws, which are located at the front two corner points and the rear center position between the lower frame and the upper frame, respectively. The transmission components include a steering box, a first connecting rod, a second connecting rod, and a third connecting rod. The lifting hand crank directly drives the lead screw at the rear center position through the third connecting rod, and synchronously drives the lead screws at the front two sides through the third connecting rod, the steering box, the first connecting rod, and the second connecting rod.

[0010] Furthermore, the flipping mechanism includes: a manual winch, a grooved fixed pulley, and a transmission cable. The manual winch is disposed on the upper frame or the lower frame, the grooved fixed pulley is disposed at the bottom of the upper frame, one end of the transmission cable is connected to the manual winch, and the other end of the transmission cable passes around the grooved fixed pulley and is connected to the cover plate frame. The manual winch is provided with a locking mechanism for controlling the winding and unwinding of the transmission cable to adjust the flipping angle of the manhole cover.

[0011] Furthermore, the front end of the cover plate frame is provided with a hanging ear, and the front part of the upper frame is provided with an upper frame support ear that matches the hanging ear. The hanging ear and the upper frame support ear are hinged through a lower end plate pin, so that the cover plate frame can rotate around the lower end plate pin.

[0012] Furthermore, the cover plate frame is a rectangular frame, and angle steel for supporting the manhole cover is provided at the four corners of the cover plate frame. Temporary fixing bolts for the cover plate are provided on the angle steel. The manhole cover has temporary fixing holes for the temporary fixing bolts to pass through, so as to detachably fix the manhole cover to the cover plate frame.

[0013] Furthermore, the rear omnidirectional wheel is equipped with a locking switch for locking and positioning the trolley after it has traveled to the target position. The rear omnidirectional wheel includes a wheel frame, a wheel, and a bearing. The wheel frame is connected to the pad at the bottom of the lower frame through a central bolt rod, giving the wheel the ability to rotate horizontally 360°. The wheel is rotatably mounted on the wheel frame through the bearing.

[0014] Furthermore, the upper surface of the upper frame is supported by support columns and diagonal support rods, which form a support platform for carrying the cover plate frame and the manhole cover.

[0015] Furthermore, the lower frame is a hexahedral frame welded from square-section aluminum alloy profiles. The lower frame includes four upright columns and eight horizontal columns. The four upright columns are vertically arranged, and the eight horizontal columns are arranged in pairs between two adjacent upright columns. A trolley handrail is installed on the lower frame, and the trolley handrail has a U-shaped frame structure.

[0016] Furthermore, the manhole cover is used to install at the manhole seat of the lower head of the steam generator. A hanging plate is provided at the position of the lower head of the steam generator adjacent to the manhole seat. The hanging plate has a hanging plate pin hole. The hanging lug of the cover frame is detachably connected to the hanging plate pin hole through the hanging plate pin shaft of the lower head.

[0017] The beneficial effects of adopting the technical solution of the present invention are: (1) The present invention has a simple structure and is easy to manufacture. Through the cooperation of the mobile chassis, the lifting mechanism and the flipping mechanism, the lifting, flipping and alignment of the 500kg manhole cover plate can be realized, which improves the efficiency and quality of disassembly and assembly. (2) The present invention adopts the screw lifting mechanism in combination with the hand crank wheel drive, which has good stability and high precision, and can realize the precise adjustment of the height of the upper frame; with the universal wheel movement and locking function, the three-dimensional positioning is accurate. (3) The present invention adopts the manual winch in combination with the locking mechanism to control the flipping angle of the cover plate. The rotation and stopping of the winch can be flexibly controlled as needed to realize the precise control of the cover plate rotation angle. The flipping angle range is large and the application range is wide. (4) The present invention can be applied to the primary side manhole of the third-generation pressurized water reactor steam generator, and can also be extended to other types of steam generators or equipment with similar lower head and manhole structures, with a wide range of applications.

[0018] The advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram illustrating the working principle of the screw-type lifting installation of the primary side manhole cover of the steam generator provided in an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of a screw-type lifting installation trolley for the primary side manhole cover of a steam generator provided in an embodiment of the present invention.

[0022] Figure 3 The image shows a bottom view of the screw-type lifting installation trolley for the primary side manhole cover of the steam generator provided in an embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram of the application scenario and the structure of the manhole at the lower end cap of the SG provided in the embodiments of the present invention.

[0024] Reference numerals: 1. Front directional wheel; 2. Rear swivel wheel; 3. Lower frame; 4. Trolley handle; 5. Manual winch; 6. Drive cable; 7. Cover plate frame lug; 8. Lead screw; 9. Grooved fixed pulley; 10. Upper frame base; 11. Lower end cap hanging plate pin; 12. Temporary cover plate fixing bolt; 13. Cover plate frame; 14. Manhole cover; 15. Upper frame; 16. Worm gear mechanism; 17. First connection 18. Connecting rod; 19. Steering box; 20. Second connecting rod; 21. Screw connecting flange seat; 22. Third connecting rod; 23. Lifting hand crank; 24. Manual winch support; 25. Upper frame support lug; 26. Diagonal support rod; 27. Support column; 28. Hanging plate; 29. ​​Hanging plate pin hole; 30. Manhole cover bolt; 31. Cover lifting hole; 32. Temporary fixing hole for cover; 33. Manhole seat; 34. SG lower end cap. Detailed Implementation

[0025] The principles and features of the present invention are described below with reference to the accompanying drawings. The embodiments described are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, they 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, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0030] In the description of the embodiments of the present 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 the present invention according to the specific circumstances.

[0031] like Figures 1 to 4As shown, this embodiment of the invention provides a screw-type lifting and installation trolley for a primary side manhole cover of a steam generator, comprising: a front directional wheel 1, a rear universal wheel 2, a lower frame 3, an upper frame 15 for supporting a manhole cover 14, a lifting mechanism for driving the upper frame 15 to rise and fall relative to the lower frame 3, a flipping mechanism for flipping the manhole cover 14, and a cover frame 13 for fixing the manhole cover 14. The front directional wheel 1 is disposed below the front part of the lower frame 3, and the rear universal wheel 2 is disposed below the rear part of the lower frame 3. The upper frame 15 is disposed above the lower frame 3, the lifting mechanism is connected between the lower frame 3 and the upper frame 15, the flipping mechanism is disposed on the upper frame 15, and the cover frame 13 is connected to the flipping mechanism.

[0032] like Figures 1 to 4 As shown, the lifting mechanism further includes: a lead screw 8, a worm gear mechanism 16, and a lifting hand crank 22. The lead screw 8 is disposed between the lower frame 3 and the upper frame 15; the worm gear mechanism 16 is disposed on the lower frame 3, and the worm wheel of the worm gear mechanism 16 is connected to the lead screw 8 in a transmission manner; the lifting hand crank 22 is connected to the worm gear mechanism 16 through a transmission component.

[0033] like Figures 1 to 4 As shown, further, there are three lead screws 8, which are located at the front two corner points and the rear center position between the lower frame 3 and the upper frame 15, respectively. The transmission components include: a steering box 18, a first connecting rod 17, a second connecting rod 19, and a third connecting rod 21. The lifting hand crank 22 directly drives the lead screw 8 at the rear center position through the third connecting rod 21, and synchronously drives the lead screws 8 at the front two sides through the third connecting rod 21, the steering box 18, the first connecting rod 17, and the second connecting rod 19.

[0034] like Figures 1 to 4 As shown, the flipping mechanism further includes: a manual winch 5, a grooved fixed pulley 9, and a transmission cable 6. The manual winch 5 is disposed on the upper frame 15 or the lower frame 3. The grooved fixed pulley 9 is disposed at the bottom of the upper frame 15. One end of the transmission cable 6 is connected to the manual winch 5, and the other end of the transmission cable 6 passes around the grooved fixed pulley 9 and is connected to the cover plate frame 13. The manual winch 5 is provided with a locking mechanism for controlling the winding and unwinding of the transmission cable 6 to adjust the flipping angle of the manhole cover 14.

[0035] like Figures 1 to 4As shown, the front end of the cover frame 13 is provided with a hanging ear, and the front part of the upper frame 15 is provided with an upper frame support ear 24 that matches the hanging ear. The hanging ear and the upper frame support ear 24 are hinged through the lower end plate pin 11, so that the cover frame 13 can be rotated around the lower end plate pin 11.

[0036] like Figures 1 to 4 As shown, the cover frame 13 is a rectangular frame, and angle steel is provided at the four corners of the cover frame 13 for supporting the manhole cover 14. Temporary fixing bolts 12 are provided on the angle steel, and the manhole cover 14 has temporary fixing holes 31 for the temporary fixing bolts 12 to pass through, for detachably fixing the manhole cover 14 to the cover frame 13.

[0037] like Figures 1 to 4 As shown, the rear omnidirectional wheel 2 is further provided with a locking switch for locking and positioning the trolley after it has traveled to the target position. The rear omnidirectional wheel 2 includes a wheel frame, a wheel, and a bearing. The wheel frame is connected to the pad at the bottom of the lower frame 3 through a central bolt rod, giving the wheel the ability to rotate horizontally 360°. The wheel is rotatably mounted on the wheel frame through the bearing.

[0038] like Figures 1 to 4 As shown, further, the upper surface of the upper frame 15 is supported by support columns 26 and inclined support rods 25, which support a bearing platform for bearing the cover frame 13 and the manhole cover 14.

[0039] like Figures 1 to 4 As shown, the lower frame 3 is a hexahedral frame welded from square-section aluminum alloy profiles. The lower frame 3 includes four uprights and eight horizontal columns. The four uprights are vertically arranged, and the eight horizontal columns are arranged in pairs between two adjacent uprights. A trolley handrail 4 is installed on the lower frame 3. The trolley handrail 4 has a U-shaped frame structure.

[0040] like Figures 1 to 4 As shown, the manhole cover 14 is further used to install at the manhole seat 32 of the lower end of the steam generator. A hanging plate 27 is provided at the position of the lower end of the steam generator adjacent to the manhole seat 32. The hanging plate 27 has a hanging plate pin hole 28. The hanging lug of the cover frame 13 is detachably connected to the hanging plate pin hole 28 through the lower end hanging plate pin shaft 11.

[0041] The beneficial effects of adopting the technical solution of the present invention are: (1) The present invention has a simple structure and is easy to manufacture. Through the cooperation of the mobile chassis, the lifting mechanism and the flipping mechanism, the lifting, flipping and alignment of the 500kg manhole cover plate can be realized, which improves the efficiency and quality of disassembly and assembly. (2) The present invention adopts the screw lifting mechanism in combination with the hand crank wheel drive, which has good stability and high precision, and can realize the precise adjustment of the height of the upper frame; with the universal wheel movement and locking function, the three-dimensional positioning is accurate. (3) The present invention adopts the manual winch in combination with the locking mechanism to control the flipping angle of the cover plate. The rotation and stopping of the winch can be flexibly controlled as needed to realize the precise control of the cover plate rotation angle. The flipping angle range is large and the application range is wide. (4) The present invention can be applied to the primary side manhole of the third-generation pressurized water reactor steam generator, and can also be extended to other types of steam generators or equipment with similar lower head and manhole structures, with a wide range of applications.

[0042] This invention relates to a heavy-duty manhole cover installation trolley, specifically a screw-type lifting installation trolley for the primary side manhole cover of a steam generator (SG) in a Generation III pressurized water reactor nuclear power plant. This invention provides a screw-type lifting installation trolley for the primary side manhole cover of a steam generator, primarily used in the opening and closing of the primary side manhole cover in a Generation III pressurized water reactor nuclear power plant. It enables the lifting, flipping, and alignment of a 500kg manhole cover, thereby improving the efficiency and quality of manhole cover installation and removal. The steam generator primary side manhole cover installation trolley provided by this invention can be adapted to the specific application, and therefore can be used for various similar SG primary side manholes.

[0043] Example like Figures 1 to 4 As shown in the embodiment of the present invention, the screw-type lifting and installation trolley for the primary side manhole cover of the steam generator mainly consists of a front directional wheel 1, a rear universal wheel 2, a lower frame 3, a trolley handle 4, a manual winch 5, a transmission cable 6, a cover frame support lug 7, a lead screw 8, a grooved fixed pulley 9, an upper frame base 10, a lower end plate hanging pin 11, a temporary fixing bolt for the cover 12, a cover frame 13, a manhole cover 14, an upper frame 15, a worm gear mechanism 16, connecting rods (first connecting rod 17, second connecting rod 19, and third connecting rod 21), a steering box 18, a lead screw connecting flange seat 20, a lifting hand crank 22, and a manual winch support 23.

[0044] The lower frame 3 is the main load-bearing component of the screw-type lifting installation trolley for the primary side manhole cover of the steam generator. It is a hexahedral frame welded from 12 square-section aluminum alloy profiles, of which 4 are uprights and the other 8 are transverse columns located on the upper and lower surfaces. The lower frame 3 is the chassis skeleton of the installation trolley and is crucial to the overall rigidity and load-bearing capacity of the entire trolley.

[0045] Square pads are welded to the bottom of the four columns of the lower frame 3. Two front directional wheels 1 are fixed to the bottom of the two front columns through the pads, and two rear swivel wheels 2 are fixed to the bottom of the two rear columns through the pads. The front directional wheels 1 and rear swivel wheels 2 at the front and rear cooperate with each other to realize the steering and movement of the trolley.

[0046] The rear swivel wheel 2 is equipped with a locking switch, which can lock the trolley after it has traveled to the target position. At the same time, the front fixed wheel 1 and the rear swivel wheel 2 together provide support for the entire trolley.

[0047] The rear swivel wheel 2 consists of a wheel frame, wheels, and bearings. The upper part of the wheel frame is connected to the bottom of the lower load-bearing frame (the square pad at the bottom of the lower frame 3) via a central bolt rod serving as the "main pivot." The wheel frame is rotatably mounted on the central bolt rod, giving the wheels 360° horizontal rotation capability; this structure forms the basis of the "swivel" design. Ball bearings are installed inside the wheels to ensure smooth rolling. Thrust bearings and wear-resistant nylon bushings are installed at the main pivot to reduce rotational resistance and improve load-bearing capacity and wear resistance. The wheel shell is made of high-strength nylon, combining toughness, lightweight, and low noise, allowing it to flexibly handle multi-directional movement and minor impacts.

[0048] The car's armrest 4 employs a composite structure of a U-shaped frame and a covering layer. The core frame is formed by bending high-strength aluminum alloy tubing, with the main body being a U-shaped push rod. The base is welded to the lower frame 3 of the vehicle body, ensuring a secure connection between the armrest and the vehicle body. The exterior is covered with a soft, non-slip TPU rubber layer, with a textured surface to enhance grip and comfort. The overall structure maintains lightweight construction while offering excellent durability.

[0049] The upper frame 15 is a rectangular frame assembled from four square steel bars. Threaded rod connecting flange seats 20 are installed at the two corner points on the front of the upper frame 15, and also at the center point of the rear crossbar of the upper frame 15. Threaded rod connecting flange seats 20 are also installed at corresponding positions on the upper surface of the lower frame 3.

[0050] The upper surface of the upper frame 15 is supported by two inclined columns (inclined support rods 25) and four upright columns (support columns 26) to support a small platform. This small platform is used to support the cover frame 13 and the manhole cover 14.

[0051] The upper frame 15 and the lower frame 3 are connected by a worm gear mechanism 16, wherein the worm is a lead screw structure, the base of the worm gear (upper frame base 10) is fixed on the lower frame 3, and the top of the lead screw 8 is fixed to the lead screw connecting flange seat 20 at the bottom of the upper frame 15 by a square flange.

[0052] The lifting hand crank (lifting hand crank 22) is an operating component that achieves mechanical transmission through manual rotation. Its structure includes a wheel, hub, handle, and output shaft. The handle is evenly distributed along the edge of the wheel for easy gripping and force application; the hub is connected to the output shaft at its center, transmitting rotational torque to the equipment. An internal ratchet self-locking mechanism ensures precise and controllable rotation.

[0053] The output shaft of the lifting hand crank (lifting hand crank 22) first directly drives the lead screw 8 at the center point of the rear crossbar of the upper frame 15 through the worm gear mechanism 16. The worm gear of the worm gear mechanism 16 can be threaded onto the lead screw 8, and the worm of the worm gear mechanism 16 can be connected to the third connecting rod 21. At the same time, the force of the driving rod is transmitted to the steering box 18 through the third connecting rod 21. The steering box 18 redirects the power from the third connecting rod 21 to a vertical output, which is output to the first connecting rod 17 and the second connecting rod 19. The first connecting rod 17 and the second connecting rod 19 drive the lead screw 8 at the front corners of the upper frame 15 through the worm gear mechanism 16 at the corresponding positions. It can be seen that driven by the lifting hand crank 22, the lead screw 8 at the three positions will rise simultaneously, thereby lifting the upper frame 15. In this configuration, the worm of the worm gear mechanism 16 is coaxially and fixedly connected to the connecting rod, and the worm wheel meshes with the worm. The worm gear mechanism 16 is mounted on the lower frame 3. The worm wheel of the worm gear mechanism 16 can be threaded to the lead screw 8. The worm wheel has a thread in its middle and is threaded onto the lead screw 8. The lead screw 8 is fixedly connected to the upper frame 15 (the lead screw 8 is not connected to the lower frame 3). Alternatively, the worm of the worm gear mechanism 16 is connected to the connecting rod, and the worm wheel meshes with the worm. The worm gear mechanism 16 is mounted on the upper frame 15, and the worm wheel of the worm gear mechanism 16 can be threaded to the lead screw 8. The lead screw 8 is fixedly connected to the lower frame 3 (the lead screw 8 is threaded onto the lead screw 8). (The upper frame 15 is not connected), or, the worm of the worm gear mechanism 16 is connected to the connecting rod, the worm wheel meshes with the worm, the worm wheel is fixedly sleeved on the lead screw 8, and the lead screw 8 is connected to the upper frame 15 and the lower frame 3 by threads (double-sided threads), or, the worm of the worm gear mechanism 16 is connected to the connecting rod, the worm wheel meshes with the worm, the worm wheel is fixedly sleeved on the lead screw 8, the lead screw 8 is rotatably connected to the lower frame 3, and the lead screw 8 is threadedly connected to the upper frame 15, or, the worm of the worm gear mechanism 16 is connected to the connecting rod, the worm wheel meshes with the worm, the worm wheel is fixedly sleeved on the lead screw 8, the lead screw 8 is threadedly connected to the lower frame 3, and the lead screw 8 is rotatably connected to the upper frame 15.

[0054] The steering gearbox 18 is used to change the direction of power transmission. Inside the steering gearbox 18 is a pair of meshing bevel gears. Power is transmitted from the horizontal input shaft, through the driving bevel gear to the driven bevel gear, thus changing the rotation direction to vertical output. The steering gearbox 18 has a compact structure, the gears are heat-treated for high wear resistance, and the sealing design prevents oil leakage.

[0055] The connecting rods (first connecting rod 17, second connecting rod 19, and screw connecting flange seat 21) are force-transmitting components connecting the output shaft of the steering box 18 to the actuator, and also connecting the drive shaft of the steering box 18 to the lifting hand crank 22. They are rigid metal rods, with one end rigidly connected via a spline to ensure lossless torque transmission; the other end is connected to the working mechanism via a universal joint to compensate for installation errors and accommodate oscillations. A positioning shoulder is provided in the middle of the rod body for fixing the bearing seat, thereby supporting the rod body on the frame and forming a stable center of rotation. Its core function is to transmit torque and withstand radial force.

[0056] The cover frame 13 is a rectangular frame assembled and welded from channel steel, with one angled angle steel at each of the four corners. One straight edge of each angle steel is used to hold the manhole cover 14 and support its weight; the center of the straight edge of the other angle steel has an opening, through which the manhole cover 14 is temporarily fixed to the cover frame 13 by inserting temporary fixing bolts 12 into the temporary fixing holes 31. The connection between the cover frame 13 and the flange cover (manhole cover 14) is a temporary, detachable connection. A short lug, at a certain angle to the plane of the cover frame 13, is provided at the end of the rectangular frame (cover frame 13), with a circular pin hole at its center.

[0057] Two symmetrical lugs 24 are provided on the front crossbeam of the upper frame 15 for matching with the lugs of the cover plate frame 13 and connected by a pin 11 to allow the cover plate 14 to rotate around the axis 11.

[0058] A relatively long lug 7 is provided on the lower surface of the middle position of the front crossbeam of the cover frame 15. A small hole is located at the distal end of the lug 7, and a steel cable 6 is fixed to the hole. The steel cable 6 extends through a grooved pulley 9 at the bottom of the upper frame 15 to the manual winch 5. When the manual winch 5 tightens the steel cable 6, the cover frame 13 can rotate around the pin 11 to the target installation position. The lug 7 can be a Z-shaped structure, with its middle portion rotatably mounted on the cover frame 15, and the lug 7 is hinged to the cover frame 13.

[0059] Two hanging plates 27 are provided at the lower end of the manhole position of the lower end cap 33 of the application object SG (near the manhole seat 32). The end of the hanging plate 27 also has a hanging plate pin hole 28 that matches the hanging lug on the cover plate frame 13. Manhole cover 14 is fixed on cover frame 13. Driven by lifting hand crank 22, manhole cover 14 and its cover frame 13 are lifted to a suitable height. The position is finely adjusted and calibrated by moving the front fixed pulley 1 and rear universal wheel 2 at the bottom of the trolley. The pin hole of the lug at the end of cover frame 13 is aligned with the pin hole 28 of the hanging plate on SG, and a pin shaft 11 is inserted. The cover frame 13 and manhole cover 14 are rotated together by rotating the manual winch 5 (or by using the cover lifting hole 30 on the top of manhole cover 4) to the target position. The manhole cover 14 is rotated to the target position, the manhole cover bolt 29 is installed, and the temporary cover fixing bolt 12 on the cover frame 13 is removed to complete the installation of manhole cover 14.

[0060] (1) The screw-type lifting installation trolley for the primary side manhole cover of the nuclear power plant steam generator of the present invention has a simple structure and is easy to manufacture. It is mainly used for the primary side manhole of the third-generation pressurized water reactor steam generator. At the same time, the top cover has a large range of flipping angles and can be used for other types of steam generators or equipment with similar lower head and manhole structures, with a wide range of applications.

[0061] (2) The screw-type lifting installation trolley for the primary side manhole cover of the steam generator of the present invention, under the premise of having universal wheels that can move freely, also has a lifting hand crank wheel that adjusts the height of the upper frame through the screw. The screw adjustment of the lifting of the heavy object has better stability and higher precision; the two functions work closely together and the positioning is accurate in all three dimensions. (3) The screw-type lifting installation trolley for the primary side manhole cover of the steam generator of the present invention uses a manual winch to control the rotation angle of the manhole cover. The winch is equipped with a locking mechanism, which can flexibly control the rotation and stop of the winch as needed, and accurately control the rotation angle of the cover.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not 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; and these 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 screw-type lifting installation trolley for the primary side manhole cover of a steam generator, characterized in that, include: The system comprises a front directional wheel (1), a rear universal wheel (2), a lower frame (3), an upper frame (15) for supporting the manhole cover (14), a lifting mechanism for driving the upper frame (15) to rise and fall relative to the lower frame (3), a flipping mechanism for flipping the manhole cover (14), and a cover frame (13) for fixing the manhole cover (14). The front directional wheel (1) is located below the front of the lower frame (3), and the rear universal wheel (2) is located below the rear of the lower frame (3). The upper frame (15) is located above the lower frame (3). The lifting mechanism is connected between the lower frame (3) and the upper frame (15). The flipping mechanism is located on the upper frame (15), and the cover frame (13) is connected to the flipping mechanism.

2. The screw-type lifting installation trolley for the primary side manhole cover of a steam generator according to claim 1, characterized in that, The lifting mechanism includes: a lead screw (8), a worm gear mechanism (16), and a lifting hand crank (22). The lead screw (8) is disposed between the lower frame (3) and the upper frame (15). The worm gear mechanism (16) is disposed on the lower frame (3), and the worm wheel of the worm gear mechanism (16) is connected to the lead screw (8) in a transmission connection. The lifting hand crank (22) is connected to the worm gear mechanism (16) through a transmission component.

3. The screw-type lifting installation trolley for the primary side manhole cover of a steam generator according to claim 2, characterized in that, The number of lead screws (8) is three. The three lead screws (8) are located at the front two corner points and the rear center position between the lower frame (3) and the upper frame (15). The transmission components include: steering box (18), first connecting rod (17), second connecting rod (19) and third connecting rod (21). The lifting hand crank (22) directly drives the lead screw (8) at the rear center position through the third connecting rod (21), and synchronously drives the lead screws (8) at the front two sides through the third connecting rod (21), the steering box (18), the first connecting rod (17) and the second connecting rod (19).

4. The screw-type lifting installation trolley for the primary side manhole cover of a steam generator according to claim 1, characterized in that, The flipping mechanism includes a manual winch (5), a grooved fixed pulley (9), and a transmission cable (6). The manual winch (5) is located on the upper frame (15) or the lower frame (3). The grooved fixed pulley (9) is located at the bottom of the upper frame (15). One end of the transmission cable (6) is connected to the manual winch (5), and the other end of the transmission cable (6) passes around the grooved fixed pulley (9) and is connected to the cover plate frame (13). The manual winch (5) is provided with a locking mechanism for controlling the winding and unwinding of the transmission cable (6) to adjust the flipping angle of the manhole cover (14).

5. The screw-type lifting installation trolley for the primary side manhole cover of a steam generator according to claim 1, characterized in that, The front end of the cover frame (13) is provided with a hanging ear, and the front part of the upper frame (15) is provided with an upper frame support ear (24) that matches the hanging ear. The hanging ear and the upper frame support ear (24) are hinged by the lower end plate pin (11), so that the cover frame (13) can be rotated around the lower end plate pin (11).

6. The screw-type lifting installation trolley for the primary side manhole cover of a steam generator according to claim 5, characterized in that, The cover frame (13) is a rectangular frame. Angle steel is provided at the four corners of the cover frame (13) for supporting the manhole cover (14). Temporary fixing bolts (12) are provided on the angle steel. The manhole cover (14) has temporary fixing holes (31) for the temporary fixing bolts (12) to pass through, so as to detachably fix the manhole cover (14) to the cover frame (13).

7. The screw-type lifting installation trolley for the primary side manhole cover of a steam generator according to claim 1, characterized in that, The rear universal wheel (2) is equipped with a locking switch for locking and positioning the trolley after it has traveled to the target position. The rear universal wheel (2) includes a wheel frame, a wheel and a bearing. The wheel frame is connected to the pad at the bottom of the lower frame (3) by a central bolt rod. The wheel is rotatably mounted on the wheel frame by the bearing.

8. The screw-type lifting installation trolley for the primary side manhole cover of a steam generator according to claim 1, characterized in that, The upper surface of the upper frame (15) is supported by a support column (26) and an inclined support rod (25) for a support platform for carrying the cover frame (13) and the manhole cover (14).

9. The screw-type lifting installation trolley for the primary side manhole cover of a steam generator according to claim 1, characterized in that, The lower frame (3) is a hexahedral frame welded from square cross-section aluminum alloy profiles. The lower frame (3) includes: four upright columns and eight horizontal columns. The four upright columns are set vertically, and the eight horizontal columns are located in pairs between two adjacent upright columns. A trolley handrail (4) is installed on the lower frame (3). The trolley handrail (4) is a U-shaped skeleton structure.

10. A screw-type lifting installation trolley for a primary side manhole cover of a steam generator according to any one of claims 1-9, characterized in that, The manhole cover (14) is used to install at the manhole seat (32) of the lower end of the steam generator. A hanging plate (27) is provided at the position of the lower end of the steam generator near the manhole seat (32). A hanging plate pin hole (28) is provided on the hanging plate (27). The lug of the cover frame (13) is detachably connected to the hanging plate pin hole (28) through the lower end hanging plate pin shaft (11).

Images