An ultrasonic scanning device for bolt holes in a reactor pressure vessel

Abstract

This invention discloses an ultrasonic scanning device for bolt holes in reactor pressure vessels, comprising: a probe mounting plate; a first water-immersed probe tilted on the mounting plate; multiple rows of second water-immersed probes arranged in a staggered diamond shape and perpendicular to the end face of the mounting plate; a monitoring camera mounted on the mounting plate for real-time monitoring of the bolt holes, the first water-immersed probe, and the second water-immersed probes; a radial stepping assembly; and a circumferential rotating assembly. Multiple rows of second water-immersed probes are arranged at the front end of the device. When scanning between holes, only three radial steps are needed, traversing the circumference of the flange surface three times to complete the entire scanning work, significantly saving scanning time. The device uses the characteristic that the structural signal of the first water-immersed probe differs depending on its distance from the bolt hole center to locate the bolt hole center position as a reference point, eliminating the need for manual judgment, reducing human intervention, and improving positioning accuracy.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power testing equipment, and specifically relates to an ultrasonic scanning device for bolt holes in reactor pressure vessels. Background Technology

[0002] The reactor pressure vessel (RPV), also known as the reactor pressure shell, withstands high temperatures, high pressures, and intense neutron radiation in the primary coolant loop system. It houses the reactor core and internal components, supports the control rod drive mechanism, and the reactor top structure. It is one of the most critical pieces of equipment in nuclear power plants and nuclear power systems, classified as a Class 1 safety, Class 1 quality, Class 1 seismic, and Class 1 quality assurance device. The reactor pressure vessel, together with the primary coolant loop piping, forms the pressure boundary of the high-pressure cooling water system, serving as the second crucial line of defense against radiation. Therefore, ensuring the stable and healthy operation of this equipment is of paramount importance in nuclear power plant non-destructive testing.

[0003] The threaded bore band of the reactor pressure vessel is located on the top of the vessel, with evenly distributed bolt holes for securing and sealing the vessel when the top cover is closed. The quality of the threaded bore band and the threaded holes affects the reliability of the tightening of the pressure vessel and the top cover, and thus the overall safety performance of the reactor pressure vessel. Therefore, developing an inspection device for the main bolt holes and the connecting band between the holes of the reactor pressure vessel is of significant practical importance and meets nuclear safety requirements.

[0004] Chinese patent application CN201310752657.9 discloses an automatic ultrasonic inspection device for threaded holes in reactor pressure vessels, including a frame, vertical support wheel assembly, drive wheel assembly, encoder assembly, circumferential support wheel assembly, and circumferential tightening wheel assembly. This device has a compact structure and effectively achieves automatic ultrasonic inspection of the internal threads and inter-hole connecting strips of the main bolt holes in nuclear reactor pressure vessels. However, the radial scanning assembly of this mechanism has too few probes. Due to the coverage limitations of a single probe, multiple steps are required, resulting in excessively long scanning times for the entire threaded hole strip. Furthermore, when calibrating the center of the internal thread of the threaded hole, manual observation of the relationship between the center of the laser beam and the threaded end plug using a laser camera is required, leading to low positioning accuracy and high skill requirements for operators. Summary of the Invention

[0005] The purpose of this invention is to provide an ultrasonic scanning device for bolt holes in reactor pressure vessels, which can complete the entire bolt hole area of ​​the pressure vessel with fewer scans, saving scanning time and providing high positioning accuracy.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a reactor pressure vessel bolt hole ultrasonic scanning device, comprising:

[0007] The vehicle body section, whose driving device moves along the pressure vessel flange connecting belt;

[0008] The scanning unit, which is installed on the vehicle body, includes:

[0009] A probe mount assembly for inspecting the bolt hole band, the probe mount assembly including a probe mounting plate, a first immersion probe tilted on the probe mounting plate, a second immersion probe arranged in multiple rows in a staggered diamond shape and perpendicular to the end face of the mounting plate, and a monitoring camera mounted on the probe mounting plate for real-time monitoring of the pressure vessel bolt holes and the status of the first and second immersion probes.

[0010] A radial stepping assembly, suspended on the rear end of the traveling vehicle body, is used to drive the probe frame assembly to move radially along the pressure vessel;

[0011] A circumferential rotating assembly, which is mounted on the radial stepping assembly, is used to drive the probe holder assembly to rotate.

[0012] The optimized circumferential rotation assembly includes a large gear located above the probe mounting plate, a connecting column connecting the large gear and the probe mounting plate, a mounting cover located above the large gear, a circumferential bearing connecting the mounting cover and the large gear to allow the mounting cover and the large gear to rotate relative to each other, a circumferential drive motor mounted on the outside of the mounting cover for driving the large gear to rotate, a drive gear fixed on the output shaft of the circumferential drive motor and meshing with the large gear, and a circumferential limiting member for limiting the rotation range of the large gear.

[0013] The optimized circumferential bearing includes an upper bearing ring and a lower bearing ring arranged coaxially and vertically, a connecting pipe passing through the lower bearing ring and fixedly connected to the upper bearing ring, the lower end of the connecting pipe being fixedly connected to a large gear, and the lower bearing ring being fixedly connected to a mounting cover.

[0014] The optimized circumferential limiting component includes a limiting piece mounted on the inner wall of the mounting cover and capable of swinging left and right, a limiting trigger mounted on the inner wall of the mounting cover and corresponding to the two extreme positions of the left and right swing of the limiting piece, and a stop block fixedly mounted on the large gear. The limiting piece is located on the path of the stop block rotating with the large gear. When the stop block presses one end of the limiting piece from one side, the other end of the limiting piece is driven to move in the opposite direction to below one of the limiting triggers, triggering the limiting trigger to control the circumferential drive motor to stop operating. At this time, the limiting piece is pressed to one extreme position by the stop block. When the stop block rotates in the opposite direction with the large gear and presses one end of the limiting piece from the other side, the other end of the limiting piece is driven to move in the opposite direction to below another limiting trigger, triggering that limiting trigger to control the circumferential drive motor to stop operating. At this time, the limiting piece is pressed to the other extreme position by the stop block.

[0015] The optimized circumferential limiting member also includes a reset spring for resetting the limiting plate. When the impact block leaves the limiting plate, the limiting plate resets and swings to a position between the two limit triggers, moving away from the range where it can trigger the limit triggers.

[0016] In an optimized configuration, the reset springs are symmetrically positioned on both sides of the limiting plate.

[0017] In the optimized configuration, the circumferential bearing includes an inner bearing disc and an outer bearing ring that are rotatably connected. The inner bearing disc is fixedly connected to the mounting cover, and the outer bearing ring is fixedly connected to the large gear.

[0018] The optimized circumferential limiting member includes a spiral guide groove formed on the lower end face of the inner bearing disk and a limiting post movably disposed on the upper end face of the large gear. The limiting post moves between the projections of the two ends of the guide groove on the upper end face of the large gear.

[0019] The optimized design includes a circumferential reference point detection switch on the upper surface of the large gear and outside the mounting cover.

[0020] In an optimized configuration, a fixed bracket is provided at the rear end of the vehicle body. The radial stepping assembly includes a radial mounting seat fixed to the fixed bracket, a radial first mounting plate mounted above the radial mounting seat and extending upward, a radial drive motor fixedly mounted on the radial first mounting plate, a radial lead screw rotatably connected to the first mounting plate and drivingly connected to the radial drive motor, a radial drive nut threadedly connected to the radial lead screw, a radial guide rail mounted on the first mounting plate and parallel to the radial lead screw, and a radial slider slidably connected to the radial guide rail and fixedly connected to the radial drive nut.

[0021] In the optimized configuration, the radial slider is fixedly connected to the mounting cover, and the radial drive motor drives the radial lead screw to rotate, thereby driving the radial slider and the mounting cover to move radially.

[0022] The optimized radial mounting base is equipped with a radial limit detection switch.

[0023] The optimized circumferential rotation assembly includes a large gear located above the probe mounting plate, a connecting column connecting the large gear and the probe mounting plate, a mounting cover located above the large gear, a circumferential bearing connecting the mounting cover and the large gear to allow the mounting cover and the large gear to rotate relative to each other, a circumferential drive motor mounted on the outside of the mounting cover for driving the large gear to rotate, a drive gear fixed on the output shaft of the circumferential drive motor and meshing with the large gear, and a circumferential limiting member for limiting the rotation range of the large gear. A circumferential reference point detection switch is provided on the upper end surface of the large gear and on the outside of the mounting cover. A radial limit detection switch is provided on the radial mounting seat. A bidirectional limit sensor is installed on the side wall of the mounting cover. The bidirectional limit sensor can simultaneously serve as a limit sensor for the radial stepping assembly and a limit sensor for the circumferential reference point detection switch.

[0024] In the optimized configuration, the projection of the bidirectional limit sensor on the large gear is on the path of the circumferential reference point detection switch as it rotates with the large gear, and the projection of the radial limit detection switch on the surface of the radial mounting base is on the path of the radial limit detection switch as it moves radially.

[0025] The beneficial effects of this invention are as follows: Multiple rows of second water-immersed probes are arranged at the front end of the equipment. When scanning between holes, only three radial steps are needed, and the entire scanning work can be completed by walking three circles around the flange surface, greatly saving scanning time. The bolt hole center position is located as a reference point by utilizing the characteristic that the structural signal differs depending on the distance between the first water-immersed probe and the bolt hole center. No manual judgment is required, resulting in low human intervention and improved positioning accuracy. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the reactor pressure vessel bolt holes equipped with an ultrasonic scanning device in Embodiment 1;

[0027] Figure 2 This is a structural schematic diagram of the vehicle body in Embodiment 1;

[0028] Figure 3 This is a schematic diagram of the inner clamping wheel assembly in Embodiment 1;

[0029] Figure 4This is a perspective view of the encoder assembly in Embodiment 1;

[0030] Figure 5 This is a cross-sectional view of the encoder assembly in Embodiment 1;

[0031] Figure 6 This is a schematic diagram of the probe holder assembly in Embodiment 1;

[0032] Figure 7 This is a three-dimensional view of the scanning unit in Embodiment 1;

[0033] Figure 8 This is a perspective view of the scanning unit from another angle in Embodiment 1;

[0034] Figure 9 This is a schematic diagram of the circumferential bearing and circumferential limiting component in Embodiment 1;

[0035] Figure 10 This is a schematic diagram of the inner bearing disc in Embodiment 1;

[0036] Figure 11 A cross-sectional view of the scanning section in Embodiment 2;

[0037] Figure 12 Top view of the circumferential limiting component when the impact block and the limiting piece are not in contact in Embodiment 2;

[0038] Figure 13 A top view of the circumferential limiting member when the limiting piece is in one of the extreme positions in Embodiment 2;

[0039] Figure 14 Top view of the circumferential limiting member when the limiting piece is in another extreme position in Embodiment 2.

[0040] Figure 15 A perspective view of the circumferential limiting component in Embodiment 2. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings:

[0042] Example 1

[0043] like Figure 1 As shown, the ultrasonic scanning device for the bolt holes of the reactor pressure vessel includes: a vehicle body and a scanning unit; the vehicle body includes a traveling vehicle body 1, a traveling drive motor, an outer positioning wheel assembly 2, an inner clamping wheel assembly 3, and an encoder assembly 4; the scanning unit includes a probe frame assembly 5, a radial stepping assembly 6, and a circumferential rotation assembly 7.

[0044] like Figure 2As shown, the vehicle body 1 has a front end and a rear end, which extend in an arc shape from the front end to the rear end. Its inner side is an arc-shaped concave side, and its outer side is an arc-shaped outward convex side. A drive wheel 8 is provided on its outer side, and a free wheel 9 is provided on its inner side. A drive motor is sealed inside the vehicle body 1 and is used to drive the drive wheel 8 to rotate. (The drive motor 1 is sealed inside the vehicle body.) Figure 1 (Not shown in the text, the connection method between the motor and the drive wheel is existing technology and is not the focus of this invention, so it will not be described in detail here). The drive wheel 8 provides the driving power for the vehicle body 1, and the free wheel 9 rolls as the vehicle body 1 moves.

[0045] The outer positioning wheel assembly 2 is mounted on the outer surface, with its axis extending downward and its height being lower than that of the drive wheel 8. The outer positioning wheel assembly 2 includes a positioning mounting block 21 fixedly mounted on the outer surface of the vehicle body 1 and a positioning wheel 22 rotatably connected to the outer positioning mounting block 21 via a bearing. The height of the positioning wheel 22 is lower than that of the drive wheel 8.

[0046] like Figure 3 As shown, the inner clamping wheel assembly 38 is mounted on the inner side, with its axis extending downwards and its height lower than that of the drive wheel 8. The inner clamping wheel assembly 38 includes a clamping housing 31 fixedly mounted on the inner side of the vehicle body 1, a first cylinder 32 mounted inside the housing, a first guide shaft 33 penetrating the clamping housing 31, a clamping base plate 34 mounted on the first guide shaft 33 via a linear bearing 39 and located outside the clamping housing 31, a clamping mounting block 35 mounted on the clamping base plate 34, and a clamping device fixedly mounted on the clamping mounting block 35. The clamping shaft 36, the clamping wheel 38 rotatably connected to the clamping shaft 36 via the copper sleeve 37, and the buffer block 39 mounted on the clamping base plate 34 and located between the clamping base plate 34 and the clamping housing 31 are all included. The copper sleeve 37 acts as a bearing, fixed to the clamping shaft 36 and rotatably connected to the clamping wheel 38. The lower end of the copper sleeve 37 has an outwardly extending first boss 371 for supporting the clamping wheel 38, and the lower end of the clamping shaft 36 has an outwardly extending second boss 361 for supporting the copper sleeve 37. The piston rod of the first cylinder 32 is fixedly connected to the first guide shaft 33.

[0047] like Figure 4-5As shown, encoder assembly 4 is mounted on the outer surface and is used to record the travel distance of the vehicle body 1. Encoder assembly 4 includes an encoder mounting base 41 fixedly connected to the outer surface of the vehicle body 1, a second cylinder 42 mounted in the encoder mounting base 41 and extending radially along the pressure vessel, an encoder mounting cylinder 43 mounted in the encoder mounting base 41 and fixedly connected to the piston rod of the second cylinder 42, an encoder 44 mounted in the encoder mounting cylinder 43, a ball bearing 45, a transfer drive shaft 46 rotatably connected to the encoder mounting cylinder 43 via the ball bearing 45, and a connection between the encoder 44 and the transfer drive shaft 46. The coupling 47 between the two components, the coding roller 48 fixed on the adapter drive shaft 46 and located outside the coding mounting cylinder 43, the shaft seal 49 installed between the adapter drive shaft 46 and the coding mounting cylinder 43, the second guide shaft 40 slidably passing through the coding fixing seat 41 and fixedly connected to the coding mounting cylinder 43, the coding limiting block 410 installed on the second guide shaft 40 at the outer end of the coding fixing seat 41, the compression spring 411 sleeved on the second guide shaft 40 and located between the outer wall of the coding fixing seat 41 and the coding limiting block 410, and the second cylinder 42 presses the coding mounting cylinder 43 against the outer wall of the pressure vessel.

[0048] like Figure 6-8 As shown, the probe mount assembly 5 is used to inspect bolt hole bands; it includes a probe mounting plate 50, a first immersion probe 51 tilted on the probe mounting plate 50, multiple rows of second immersion probes 52 arranged in a staggered diamond shape and perpendicular to the end face of the mounting plate, and a monitoring camera 53 mounted on the probe mounting plate 50 for real-time monitoring of the bolt holes of the pressure vessel and the status of the first and second immersion probes 51 and 52. Multiple rows of second immersion probes 52 are arranged at the front end of the equipment. When scanning between holes, only three radial steps are needed, and the entire scanning work can be completed by walking three circles around the flange surface, greatly saving scanning time. The first immersion probe 51 uses the characteristic of different structural signals when its distance from the center of the bolt hole is different to find the center position of the bolt hole as a reference point, eliminating the need for manual judgment, reducing the requirements for humans, and improving positioning accuracy.

[0049] A circumferential rotating assembly 7, mounted on the radial stepping assembly 6, is used to drive the probe holder assembly 5 to rotate. The circumferential rotating assembly 7 includes a large gear 71 located above the probe mounting plate 50, a connecting column 72 connecting the large gear 71 and the probe mounting plate 50, a mounting cover 73 located above the large gear 71, a circumferential bearing 74 connecting the mounting cover 73 and the large gear 71 to allow relative rotation between them, a circumferential drive motor 75 mounted on the outside of the mounting cover 73 and used to drive the large gear 71 to rotate, a drive gear 76 fixed on the output shaft of the circumferential drive motor 75 and meshing with the large gear 71, and a circumferential limiting member 77 for limiting the rotation range of the large gear 71. Figure 9As shown, the circumferential bearing 74 includes an inner bearing disc 741 and an outer bearing ring 742 that are rotatably connected. The inner bearing disc 741 and the outer bearing ring 742 are inclined and fitted together, with the distance between their mating surfaces increasing from top to bottom. An inwardly tapering limiting ring 7421 is formed at the upper end of the outer bearing ring 742 to prevent the outer bearing ring 742 from tilting relative to the inner bearing disc 741 during rotation. The inner bearing disc 741 is fixedly connected to the mounting cover 73 via a fixed connecting post 731, and the outer bearing ring 742 is fixedly connected to the large gear 71. Figure 10 As shown, the circumferential limiting member 77 includes a spiral guide groove 771 formed on the lower end face of the inner bearing disk 741, which is not continuous in the vertical direction, and a limiting post 772 movably disposed on the upper end face of the large gear 71. The large gear 71 is provided with a limiting sliding cover 773, which is wider at the bottom and narrower at the top. The limiting post 772 is thicker at the bottom and thinner at the top. Its lower end is slidably disposed within the limiting sliding cover 773 and cannot fall off the limiting sliding cover 773. Its upper end extends out of the limiting sliding cover 773 and is inserted into the guide groove 771. The limiting post 772 moves between the projections of its two endpoints on the upper end face of the large gear 71 in the guide groove 771. The travel range of the limiting post 772 within the guide groove 771 is greater than 360°, and in this embodiment, it is -190° to 190°.

[0050] A radial stepping assembly 6 is suspended on the rear end of the traveling vehicle body 1 and is used to drive the probe frame assembly 5 to move radially along the pressure vessel. A fixed bracket 61 is provided on the rear end of the traveling vehicle body 1. The radial stepping assembly 6 includes a radial mounting seat 62 fixed on the fixed bracket 61, a radial first mounting plate 63 mounted above the radial mounting seat 62 and extending upward, a radial drive motor 64 fixedly mounted on the radial first mounting plate 63, a radial lead screw 65 rotatably connected to the first mounting plate 63 and drivingly connected to the radial drive motor 64, a radial drive nut 610 threadedly connected to the radial lead screw 65, a radial guide rail 67 mounted on the first mounting plate 63 and arranged parallel to the radial lead screw 65, and a radial slider 68 slidably connected to the radial guide rail 67 and fixedly connected to the radial drive nut. The radial slider 68 is fixedly connected to the mounting cover 73. The radial drive motor 64 drives the radial lead screw 65 to rotate through the pulley assembly 60, thereby driving the radial slider 68 and the mounting cover 73 to move radially. A circumferential reference point detection switch 78 is provided on the upper end surface of the large gear 71 and on the outside of the mounting cover 73. A radial limit detection switch 69 is provided on the radial mounting base 62. A bidirectional limit sensor 607 is installed on the side wall of the mounting cover 73. The projection of the bidirectional limit sensor 607 on the large gear 71 is on the path of the circumferential reference point detection switch 78 as the large gear 71 rotates, and the projection of the bidirectional limit sensor 607 on the surface of the radial mounting base 62 where the radial limit detection switch 69 is installed is on the path of the radial limit detection switch 69 moving radially. The bidirectional limit sensor 607 can simultaneously serve as the limit sensor for the radial stepping component and the limit sensor for the circumferential reference point detection switch, making the overall structure of the device more compact.

[0051] The working principle of this invention is as follows:

[0052] (1) Before the scanning device is hoisted into the surface of the object to be inspected, pressure-holding gas is introduced in advance to maintain pressure.

[0053] (2) The scanning device is suspended on the surface of the flange connecting belt of the reactor pressure vessel by a gantry crane. Personnel on shore use a long rod to press the outer positioning wheel assembly against the outer side wall of the pressure vessel. Then the gantry crane continues to lower the scanning device to stabilize it.

[0054] (3) The inner clamping wheel assembly retracts to bring the clamping wheel close to the inner surface of the pressure vessel flange connecting strip, and the second cylinder of the encoder assembly retracts to bring the encoder roller close to the outer side of the pressure vessel flange connecting strip.

[0055] (4) When scanning the threaded hole band, rotate the circumferential rotating component to trigger the reference point detection switch on the circumferential rotating component. At this time, one side of the diamond-shaped scanning band formed by the second water immersion probe rotates to the radial direction of the pressure vessel, and then the scanning device begins scanning. The scanning mode adopted by the scanning device is a cyclic mode in which the scanning device travels around the flange connecting band threaded hole band once, the radial stepping component steps by one step value, and then the scanning device continues to travel around once more. The radial stepping component only needs to take three radial steps, and the scanning device can check all the inter-hole connecting bands after traveling around the threaded hole band three times.

[0056] (5) When inspecting the internal threads of the threaded holes on the flange connecting strip, first step the radial stepping assembly to a fixed position, then the scanning device moves automatically. When the probe frame assembly moves above the threaded hole, the circumferential rotation assembly rotates circumferentially. The first water-immersed probe, which is tilted on the probe frame assembly, emits a signal and receives the reflected signal. Based on the principle that different structural signals are generated due to different distances between the first water-immersed probe and the center of the bolt hole, the positional relationship between the center of the probe frame assembly and the center of the threaded hole is determined. The vehicle body is manually controlled to move back and forth until the center of the probe frame assembly coincides with the center of the threaded hole. At this point, the position is the reference point for inspecting the threaded hole. Since the scanning device has high walking accuracy, it is not necessary to find the reference point for each threaded hole. The reference point is calibrated once every ten threaded holes. Within these ten holes, the scanning device only needs to travel a fixed distance each time to meet the requirements of ultrasonic testing. This improves the positional accuracy of the scanning device and saves the total testing time.

[0057] Example 2

[0058] like Figure 11 As shown, the difference between this embodiment and Embodiment 1 lies in the circumferential bearing 74 and the circumferential limiting member 77. In this embodiment, the circumferential bearing 74 includes an upper bearing ring 743 and a lower bearing ring 744 that are coaxially arranged and positioned vertically, and a connecting pipe 745 that passes through the lower bearing ring 744 and is fixedly connected to the upper bearing ring 743. The lower end of the connecting pipe 745 is fixedly connected to the large gear 71, and the lower bearing ring 744 is fixedly connected to the mounting cover 73. Figure 12-15As shown, the circumferential limiting component 77 includes a limiting mounting block 778 mounted on the inner wall of the mounting cover 73, a limiting piece 774 mounted on the lower end surface of the limiting mounting block 778 and capable of swinging left and right, a limiting trigger 775 mounted on the limiting mounting block 778 and corresponding to the two extreme positions of the left and right swing of the limiting piece, and a stop block 776 fixedly mounted on the large gear 73. The limiting piece 774 is on the path of the stop block 776 as the large gear 73 rotates. When the stop block 776 presses one end of the limiting piece 774 from one side, the other end of the limiting piece 774 is driven to move in the opposite direction to below one of the limiting triggers 775, triggering the limiting trigger 775 to control the circumferential drive motor 75 to stop running. At this time, the limiting piece 774 is pressed by the stop block 776 to its... At one extreme position, when the impact block 776 rotates in the opposite direction with the large gear 73 and presses one end of the limiting plate 774 from the other side, the other end of the limiting plate 774 is driven to move in the opposite direction to below another limiting trigger 775, and triggers the limiting trigger 775 to control the circumferential drive motor 75 to stop running. At this time, the limiting plate 774 is pressed to another extreme position by the impact block, that is, the circumferential stroke can exceed 360°. The circumferential limiting member 77 also includes a return spring 777 to reset the limiting plate 774. When the impact block 773 leaves the limiting plate 774, the limiting plate 774 resets and swings to the position between the two limiting triggers 775, leaving the range where it can trigger the limiting trigger 775. The return spring 777 is symmetrically arranged on both sides of the limiting plate 774.

[0059] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A reactor pressure vessel bolt hole equipped with an ultrasonic scanning device, characterized in that, It includes: The vehicle body section, whose driving device moves along the pressure vessel flange connecting belt, includes a traveling vehicle body; The scanning unit, which is installed on the vehicle body, includes: A probe mount assembly for inspecting the bolt hole band, the probe mount assembly including a probe mounting plate, a first immersion probe inclinedly disposed on the probe mounting plate, multiple rows of staggered second immersion probes arranged in a rhombus shape and disposed perpendicular to the end face of the mounting plate, and a monitoring camera mounted on the probe mounting plate for real-time monitoring of the pressure vessel bolt holes and the status of the first and second immersion probes. A radial stepping assembly, suspended on the rear end of the traveling vehicle body, is used to drive the probe frame assembly to move radially along the pressure vessel; A circumferential rotating assembly, mounted on the radial stepping assembly, is used to drive the probe holder assembly to rotate. The circumferential rotating assembly includes a large gear located above the probe mounting plate, a connecting column connecting the large gear and the probe mounting plate, a mounting cover located above the large gear, a circumferential bearing connecting the mounting cover and the large gear to allow the mounting cover and the large gear to rotate relative to each other, a circumferential drive motor mounted on the outside of the mounting cover and used to drive the large gear to rotate, a drive gear fixed on the output shaft of the circumferential drive motor and meshing with the large gear, and a circumferential limiting member used to limit the rotation range of the large gear.

2. The reactor pressure vessel bolt hole ultrasonic scanning device according to claim 1, characterized in that: The circumferential bearing includes an upper bearing ring and a lower bearing ring arranged coaxially and vertically, and a connecting pipe passing through the lower bearing ring and fixedly connected to the upper bearing ring; the lower end of the connecting pipe is fixedly connected to the large gear, and the lower bearing ring is fixedly connected to the mounting cover.

3. The reactor pressure vessel bolt hole ultrasonic scanning device according to claim 1, characterized in that: The circumferential limiting component includes a limiting plate mounted on the inner sidewall of the mounting cover and capable of swinging left and right, a limiting trigger mounted on the inner sidewall of the mounting cover and corresponding to the two extreme positions of the left and right swing of the limiting plate, and a stop block fixedly mounted on the large gear. The limiting plate is located on the path of the stop block as it rotates with the large gear. When the stop block presses against one end of the limiting plate from one side, the other end of the limiting plate is driven to move in the opposite direction below one of the limiting triggers, triggering the limiting trigger to control the circumferential drive motor to stop operating. At this time, the limiting plate is pressed to one extreme position by the stop block. When the stop block rotates in the opposite direction with the large gear and presses against one end of the limiting plate from the other side, the other end of the limiting plate is driven to move in the opposite direction below another limiting trigger, triggering that limiting trigger to control the circumferential drive motor to stop operating. At this time, the limiting plate is pressed to the other extreme position by the stop block.

4. The reactor pressure vessel bolt hole ultrasonic scanning device according to claim 3, characterized in that: The circumferential limiting member also includes a reset spring for resetting the limiting plate. When the impact block leaves the limiting plate, the limiting plate resets and swings to a position between the two limit triggers, moving away from the range where it can trigger the limit triggers.

5. The reactor pressure vessel bolt hole ultrasonic scanning device according to claim 4, characterized in that: The reset springs are symmetrically arranged on both sides of the limiting plate.

6. The reactor pressure vessel bolt hole ultrasonic scanning device according to claim 1, characterized in that: The circumferential bearing includes an inner bearing disc and an outer bearing ring that are rotatably connected. The inner bearing disc is fixedly connected to the mounting cover, and the outer bearing ring is fixedly connected to the large gear.

7. The reactor pressure vessel bolt hole ultrasonic scanning device according to claim 6, characterized in that: The circumferential limiting member includes a spiral guide groove formed on the lower end face of the inner bearing disk and a limiting post movably disposed on the upper end face of the large gear; the limiting post moves between the projections of the two endpoints of the guide groove on the upper end face of the large gear.

8. The reactor pressure vessel bolt hole ultrasonic scanning device according to claim 1, characterized in that: A circumferential reference point detection switch is provided on the upper end surface of the large gear and on the outside of the mounting cover.

9. The reactor pressure vessel bolt hole ultrasonic scanning device according to claim 1, characterized in that: The rear end of the vehicle body is provided with a fixed bracket. The radial stepping assembly includes a radial mounting seat fixed on the fixed bracket, a first mounting plate mounted above the radial mounting seat and extending upward, a radial drive motor fixedly mounted on the first mounting plate, a radial lead screw rotatably connected to the first mounting plate and drivingly connected to the radial drive motor, a radial drive nut threadedly connected to the radial lead screw, a radial guide rail mounted on the first mounting plate and arranged parallel to the radial lead screw, and a radial slider slidably connected to the radial guide rail and fixedly connected to the radial drive nut.

10. The reactor pressure vessel bolt hole ultrasonic scanning device according to claim 9, characterized in that: The radial slider is fixedly connected to the mounting cover, and the radial drive motor drives the radial lead screw to rotate, thereby driving the radial slider and the mounting cover to move radially.

11. The reactor pressure vessel bolt hole ultrasonic scanning device according to claim 9, characterized in that: The radial mounting base is equipped with a radial limit detection switch.

12. The reactor pressure vessel bolt hole ultrasonic scanning device according to claim 9, characterized in that: The circumferential rotation assembly includes a large gear located above the probe mounting plate, a connecting column connecting the large gear and the probe mounting plate, a mounting cover located above the large gear, a circumferential bearing connecting the mounting cover and the large gear to allow the mounting cover and the large gear to rotate relative to each other, a circumferential drive motor mounted on the outside of the mounting cover for driving the large gear to rotate, a drive gear fixed on the output shaft of the circumferential drive motor and meshing with the large gear, and a circumferential limiting member for limiting the rotation range of the large gear; a circumferential reference point detection switch is provided on the upper end surface of the large gear and on the outside of the mounting cover, a radial limit detection switch is provided on the radial mounting seat, and a bidirectional limit sensor is installed on the side wall of the mounting cover. The bidirectional limit sensor can simultaneously serve as a limit sensor for the radial stepping assembly and a limit sensor for the circumferential reference point detection switch.

13. The reactor pressure vessel bolt hole ultrasonic scanning device according to claim 12, characterized in that: The projection of the bidirectional limit sensor on the large gear is on the path of the circumferential reference point detection switch as it rotates with the large gear, and the projection of the radial limit detection switch on the surface of the radial mounting base is on the path of the radial limit detection switch as it moves radially.

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