Nondestructive testing device suitable for nuclear power plant pressure-bearing expansion joint circular seam

Abstract

The invention provides a nondestructive testing device suitable for a circumferential seam of a pressure-bearing expansion joint of a nuclear power plant. The nondestructive testing device comprises a bracket, a circumferential X-ray instrument, a hidden bag and an image quality indicator, the bracket comprises a mounting seat arranged at the central position of the pressure-bearing expansion joint; the circumferential X-ray instrument is mounted on the mounting seat, the dark bag surrounds the outer side of an annular welding seam of the pressure-bearing expansion joint, an unexposed negative film is arranged in the dark bag, and the image quality indicator is arranged at the annular seam in the pressure-bearing expansion joint; the telescopic supporting legs are evenly distributed in the circumferential direction of the mounting base and can stretch out and draw back synchronously; each telescopic supporting leg comprises a fixed part and a telescopic part, one end of each fixed part is connected with the mounting base, the other end of each fixed part extends out in the radial direction and is in sliding connection with the telescopic part, the multiple telescopic supporting legs stretch out and draw back synchronously, it can be guaranteed that the position, located in the center of the pressure-bearing expansion joint, of the circumferential X-ray instrument is not changed, scales are arranged on the telescopic parts, focal length reading is convenient, and the working efficiency is improved. Workers can conveniently measure the geometric undefinition through the focal length, the use is convenient, and the time is saved.

Description

Technical Field

[0001] This invention relates to the field of non-destructive testing technology for nuclear power units, and in particular to a non-destructive testing device suitable for the circumferential seam of pressure expansion joints in nuclear power plants. Background Technology

[0002] Pressure expansion joints (also known as metal expansion joints, bellows expansion joints, or compensators) are widely used in pressure equipment or piping systems in nuclear power plants. Expansion joints have circumferential welds, and during the manufacturing process, they need to be inspected by a circumferential X-ray machine (radiological inspection) to obtain the geometric unsight parameters of the expansion joint and determine whether there are any defects.

[0003] In the existing technology, the circumferential X-ray instrument must be placed inside the expansion joint to inspect the weld seam around the perimeter. The placement of the circumferential X-ray instrument must be at the center of the expansion joint, which requires measuring the center of the expansion joint. At the same time, the distance from the circumferential X-ray instrument or its radiation source to the inner wall of the expansion joint, i.e., the focal length, must also be measured in order to calculate the geometric blur. This makes the operation of the circumferential X-ray instrument quite cumbersome, time-consuming and labor-intensive. Summary of the Invention

[0004] This invention provides a non-destructive testing device for the circumferential weld of pressure expansion joints in nuclear power plants, thereby alleviating the technical problems of the cumbersome, time-consuming, and labor-intensive operation of using circumferential X-ray instruments.

[0005] This invention provides a non-destructive testing device for the circumferential weld of a pressure expansion joint in a nuclear power plant. The device includes: a support, a circumferential X-ray machine, a dark bag, and an image quality meter. The support is detachably mounted within the pressure expansion joint and includes a mounting base located at the center of the joint. The circumferential X-ray machine is mounted on the mounting base and is used to emit X-rays radially from the center towards the circumferential weld. The dark bag surrounds the outside of the circumferential weld of the pressure expansion joint and allows X-rays to pass through it for holding an unexposed film. The image quality meter is located at the circumferential weld within the pressure expansion joint. The bracket further includes multiple telescopic legs that are evenly distributed around the circumference of the mounting base and can extend and retract synchronously. The multiple telescopic legs are arranged in the same plane parallel to the plane where the circumferential weld is located. Each telescopic leg includes a fixed part and a telescopic part. One end of the fixed part is connected to the mounting base, and the other end of the fixed part extends radially. One end of the telescopic part is slidably mounted on the fixed part and can press and support the other end against the inner wall of the pressure-bearing expansion joint under the action of the driving device. The multiple fixed parts are of equal length, and each of the multiple telescopic parts is provided with a scale for measuring the extension length of the telescopic part.

[0006] In one embodiment of the present invention, multiple image quality meters are arranged along the annular weld seam.

[0007] In one embodiment of the present invention, the fixing part is a hollow sleeve rod, the telescopic part is a sliding rod, and one end of the sliding rod is slidably inserted into the hollow sleeve rod.

[0008] In one embodiment of the present invention, the driving device has a plurality of driving ends that drive the telescopic part to move synchronously.

[0009] In one embodiment of the present invention, the driving device further has a vertical moving end, the moving direction of the vertical moving end is perpendicular to the plane where the annular weld is located and passes through the center position of the pressure-bearing expansion joint; the driving device is provided with a push-pull connecting rod at the driving end, one end of the push-pull connecting rod is rotatably connected to the vertical moving end, and the other end is rotatably connected to the telescopic part, one end of the push-pull connecting rod is driven to move by the vertical moving end, and pulls the other end of the push-pull connecting rod to drive the telescopic part to move.

[0010] In one embodiment of the present invention, the connection position of the push-pull link and the telescopic part is near the end of the telescopic part that is pressed against and supported on the inner wall of the pressure-bearing expansion joint.

[0011] In one embodiment of the present invention, the driving device is provided with a vertical rod and a collar at the vertical moving end. The collar is slidably sleeved on the vertical rod, and one end of the push-pull connecting rod is rotatably connected to the collar. The collar drives one end of the push-pull connecting rod to move along the moving direction of the vertical moving end by sliding on the vertical rod.

[0012] In one embodiment of the present invention, a support frame is connected below the vertical rod, and the support frame is detachably mounted on the circumferential X-ray instrument.

[0013] In one embodiment of the present invention, the support frame is a ring frame.

[0014] In one embodiment of the present invention, the end of the telescopic part that presses against and supports the inner sidewall of the pressure-bearing expansion joint is further provided with a pad.

[0015] The beneficial effects of this invention: The non-destructive testing device for the circumferential weld of the pressure expansion joint proposed in this invention ensures that the position of the circumferential X-ray instrument at the center of the pressure expansion joint remains unchanged due to the synchronous extension and retraction of the three telescopic legs. This not only facilitates the X-ray inspection of the circumferential weld but also ensures that the focal length of the circumferential X-ray instrument to the surrounding films is the same, making it easier for workers to calculate the geometric blur by measuring the focal length, which is a key parameter for judging the quality of the circumferential weld.

[0016] Because the telescopic part is equipped with a scale for reading the extension length, the extension value can be read directly through the scale after the telescopic part extends to the inner wall of the pressure expansion joint. After measuring the fixed length of other components and the distance to the circumferential X-ray instrument in advance, the focal length can be obtained. It is convenient to use, saves time, and eliminates the need to measure the focal length separately. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0018] In the attached diagram:

[0019] Figure 1 This is a schematic diagram of the non-destructive testing device in use according to an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the extended state of the telescopic part of the non-destructive testing device in one embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the telescopic part of the non-destructive testing device in one embodiment of the present invention retracted to its original state;

[0022] Figure 4 for Figure 2 Diagram of direction A in the middle.

[0023] Figure 5 This is a schematic diagram showing the setup of the driving device for a non-destructive testing apparatus according to an embodiment of the present invention.

[0024] Figure 6 This is a cross-sectional view of the dark bag of a non-destructive testing device according to an embodiment of the present invention.

[0025] The attached figures are labeled as follows:

[0026] 100. Pressure-bearing expansion joint; 200. Bracket; 210. Telescopic outrigger; 211. Fixing part; 212. Telescopic part; 220. Mounting base; 300. Circumferential X-ray machine; 400. Film; 500. Image quality meter; 600. Dark bag; 700. Drive device; 710. Vertical rod; 720. Collar; 730. Push-pull linkage; 740. Support frame. Detailed Implementation

[0027] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0028] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0029] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the invention.

[0030] Please see Figures 1 to 6 This invention provides a non-destructive testing device for the circumferential weld of a pressure expansion joint 100 in a nuclear power plant. The device includes a support 200, a circumferential X-ray machine 300, a dark bag 600, and an image quality meter 500. The device facilitates X-ray inspection of the circumferential weld and ensures that the focal length of the circumferential X-ray machine 300 and the surrounding films 400 are uniform. This allows operators to easily calculate the geometric blur using the focal length, a key parameter for judging the quality of the circumferential weld. The device is easy to operate, saving time and labor costs.

[0031] Please see Figure 1 and Figure 6 The circumferential X-ray machine 300 emits X-rays in all directions, which penetrate the dark bag 600 through the annular weld and reach the film 400. The film 400 is then removed from the dark bag 600 in a dark chamber. After a series of operations such as film processing, the film is developed on the film 400, and the defect of the annular weld can be seen in the displayed image. The film 400 is designed according to the circumference of the annular weld to be inspected on the pressure expansion joint 100. The film 400 can be a single piece or multiple pieces, as long as it completely surrounds the annular weld. Please refer to [link / reference]. Figure 1 In this embodiment, four are set. To ensure complete coverage of the circumferential weld, adjacent substrates 400 can overlap.

[0032] Please see Figure 1The image quality meter 500 is used to quantitatively evaluate the image quality of the radiographic film 400 to verify whether the detection sensitivity meets the relevant standard requirements. After X-ray irradiation, the image quality meter 500 forms unique image features on the film 400, which are clearly distinguishable from the circumferential weld image, facilitating accurate identification by staff. By judging the clarity and completeness of the image from the image quality meter 500, an objective assessment of the quality of the film 400 can be made: if the image from the image quality meter 500 is unclear or cannot be completely identified, it indicates that the overall quality of the film 400 is unqualified and should be discarded and retaken; only when the image from the image quality meter 500 is clear, complete, and distinguishable can it be proven that the imaging quality of the film 400 meets the requirements, and only then can the image of the circumferential weld be used for defect assessment.

[0033] Ideally, the number of image quality meters 500 should be equal to the number of films 400, or each film 400 should display an image of the image quality meter 500. However, in one embodiment, even if a single film 400 can completely cover the circumferential weld, since it is a circumferential weld, the X-rays from the circumferential X-ray machine 300 also emit a ring of rays in all directions, resulting in a large detection range. To avoid errors, at least 3 to 4 image quality meters 500 should be evenly arranged circumferentially to ensure that images of the film 400 at different positions can be compared using the image quality meters 500. Please refer to [link to relevant documentation]. Figure 1 In this embodiment, four image quality meters 500 are provided.

[0034] Please see Figures 1 to 4 The circumferential X-ray unit 300 is a cylindrical structure, which is fixed to the bracket 200 via a mounting base 220. The mounting base 220 can be a circular frame, frustum, square platform, ring frame, or any structure that can be fixed to the circumferential X-ray unit 300 and accommodate the telescopic legs 210. For larger circumferential X-ray units 300, it is not necessary to mount them on the bracket 200; as long as the bracket 200 is fixed to them, it is sufficient. When the circumferential X-ray unit 300 needs to move with the bracket 200, a sliding structure, such as a sliding seat, can be provided below it. This embodiment uses a ring frame to facilitate the installation of the telescopic legs 210. Multiple telescopic legs 210 are evenly distributed on the mounting base 220 along the circumference of the circumferential X-ray unit 300. The telescopic legs 210 are structures that can achieve telescopic functionality; there are no limitations on their specific features.

[0035] Please see Figure 1 and Figure 2In this embodiment, three telescopic outriggers 210 are provided. Each telescopic outrigger 210 includes a fixed part 211 and a telescopic part 212. One end of the fixed part 211 is connected to the mounting base 220, and the other end of the fixed part 211 extends radially. One end of the telescopic part 212 is slidably mounted on the fixed part 211. The three telescopic outriggers 210 extend synchronously. Specifically, under the action of the driving device 700, the telescopic part 212 slides out from the fixed part 211 and extends outward synchronously. The extended end presses against the inner wall of the pressure-bearing expansion joint 100, achieving a supporting effect and thus stabilizing the circumferential X-ray instrument 300 on the bracket 200. On the other hand, since the telescopic outriggers 210 extend and retract synchronously, they also have the following effects:

[0036] Please see Figure 2 and Figure 3 The length of the telescopic outrigger 210 when it is extended (i.e., the length of the telescopic part 212 extending outward) is denoted as L1; the original length of the telescopic outrigger 210 (i.e., the state where the telescopic part 212 is not extended and is fully retracted) is denoted as L2; ​​and the distance from the end of the telescopic outrigger 210 whose fixing part 211 is connected to the bracket 200 to the circumferential X-ray instrument 300 is denoted as L3.

[0037] Because the three telescopic legs 210 extend and retract synchronously, their respective extension lengths L1 are equal. Furthermore, since the distances L3 from the ends of the three telescopic legs 210 connected to the bracket 200 to the circumferential X-ray instrument 300 are equal, and their original lengths L2 are all the same, and the three telescopic legs 210 are positioned in the same plane parallel to the plane of the circumferential weld, when the extended ends of the three synchronously extending and retracting telescopic legs 210 abut against the inner wall of the pressure-bearing expansion joint 100, it also means that the distances from the circumferential X-ray instrument 300 along the extension directions of the three telescopic legs 210 to the inner wall of the pressure-bearing expansion joint 100 are all equal. This avoids the situation where, during the adjustment of the extension of the telescopic legs 210, if each leg 210 is adjusted individually, inconsistent coordination or operator error could cause the central mounting base 220 to move, thus affecting the position of the circumferential X-ray instrument 300 and causing it to no longer be centered, thus affecting its circumferential X-ray detection effect.

[0038] Therefore, due to the synchronous extension and retraction of the three telescopic outriggers 210, it can be ensured that the circumferential X-ray instrument 300 remains in the center position of the pressure expansion joint 100. This is not only beneficial for the X-ray inspection of the circumferential weld, but also ensures that the focal length of the circumferential X-ray instrument 300 to the surrounding films 400 is the same, which makes it easier for the staff to calculate the geometric blur by measuring the focal length, as a key parameter for judging the quality of the circumferential weld.

[0039] Meanwhile, the value obtained by L1+L2+L3 is the focal length. Since the values ​​of L2 and L3 are constant and will not change with the extension and retraction of the telescopic outrigger 210, only L1 needs to be measured. Preferably, the telescopic part 212 is provided with a scale for reading the extension length. After the telescopic outrigger 210 extends to the inner wall of the pressure expansion joint 100, the value can be directly read by the scale as L1. This setting is convenient to operate, saves time and labor costs, and eliminates the need to measure the focal length separately.

[0040] The fixing part 211 is a hollow sleeve rod, and the telescopic part 212 is a sliding rod. One end of the sliding rod slides through the hollow sleeve rod. The sliding rod and sleeve rod are simple to manufacture and easy for personnel to use. The shape of the sliding rod and sleeve rod can be a square rod, a round rod, or even an elliptical rod. In this embodiment, it is a round rod. When the sliding rod slides out of the sleeve rod, the force is evenly distributed around the round rod, making it easier to slide.

[0041] Please see Figure 5 In this embodiment, the driving device 700 has multiple driving ends that drive the telescopic parts 212 to move synchronously, thereby ensuring that the circumferential X-ray instrument 300 remains in the central position. In this embodiment, the number of driving ends is the same as the number of telescopic parts 212; there are three telescopic parts 212 and three driving ends. The number of driving ends may also differ from the number of telescopic parts 212, but at least each telescopic part 212 must be driven by a driving end.

[0042] The drive unit 700 also has a vertical moving end; please refer to [link / reference]. Figure 2 and Figure 3 Based on the arrangement of the telescopic parts 212, the movement directions of the multiple telescopic parts 212 are radial. To achieve synchronous movement, the drive end must also move in the same direction. Please refer to [link / reference needed]. Figure 5 In this embodiment, a push-pull link 730 is specifically provided at the drive end. One end of the push-pull link 730 is rotatably connected to the vertical moving end, and the other end is rotatably connected to the telescopic part 212. When the vertical moving end moves along the moving direction, it drives the push-pull link 730 and its connected end to move in the vertical direction. The other end of the push-pull link 730 can then synchronously drive the telescopic part 212 to move, realizing the radial movement of multiple telescopic parts 212. Furthermore, since the moving direction of the vertical moving end is along the vertical direction of the plane where the annular weld is located and passes through the center position of the pressure-bearing expansion joint 100, and each push-pull link 730 should be circumferentially symmetrically designed or can ensure that after one end is subjected to force, the other end moves synchronously. For example, the length of each push-pull link 730 should be set to be consistent, and the connection positions on the vertical moving end and the telescopic part 212 should be circumferentially symmetrical. Therefore, multiple telescopic parts 212 can achieve synchronous movement.

[0043] Please see Figure 5In this embodiment, a vertical rod 710 and a collar 720 are specifically provided at the vertical moving end. The shape of the vertical rod 710 and the collar 720 is not limited and can be circular or square, as long as the collar 720 slides on the vertical rod 710. The vertical rod 710 serves as a guide, enabling the collar 720 to move along the moving direction of the vertical moving end. One end of the push-pull connecting rod 730 is rotatably connected to the collar 720. By sliding the collar 720 on the vertical rod 710, one end of the push-pull connecting rod 730 can be moved along the moving direction of the vertical moving end, thereby enabling the movement of the telescopic part 212 at the other end of the push-pull connecting rod 730. For multiple telescopic parts 212, synchronous movement can be achieved. The design structure of the vertical rod 710 and the collar 720 is simple and convenient for personnel to operate.

[0044] Please see Figure 5 The connection point between the push-pull linkage 730 and the telescopic part 212 is located at one end near the telescopic part 212, which is pressed against and supported on the inner wall of the pressure-bearing expansion joint 100.

[0045] A support frame 740 is connected below the vertical rod 710 to support the vertical rod 710. The support frame 740 is detachably mounted on the circumferential X-ray instrument 300 and can be removed for convenient storage when not in use. The support frame 740 is a ring frame, which provides stable support. The frame structure design reduces the amount of material used while facilitating observation of the upper part of the circumferential X-ray instrument 300 and enabling necessary operations.

[0046] The telescopic section 212, which presses against the inner wall of the pressure-bearing expansion joint 100, also has a padding layer at one end. The padding layer is made of a material that is not easily scratched by the inner wall of the pressure-bearing expansion joint 100, but it cannot be elastic. This is because the thickness of the padding layer needs to be taken into account when measuring the focal length. If the padding layer has a certain degree of elasticity, its thickness will change due to pressure when the telescopic section 212 presses against the inner wall of the pressure-bearing expansion joint 100, requiring a re-measurement of its thickness to ensure an accurate focal length value, thus complicating the focal length measurement. The padding layer can be either a block located at one end of the telescopic section 212 or a ring wrapped around the inner wall of the pressure-bearing expansion joint 100, as long as it prevents scratches between the telescopic section 212 and the inner wall of the pressure-bearing expansion joint 100.

[0047] This invention proposes a non-destructive testing device for the circumferential weld of a pressure expansion joint in a nuclear power plant. By synchronously extending and retracting all three telescopic legs, the circumferential X-ray machine's position at the center of the pressure expansion joint remains constant. This not only facilitates X-ray inspection of the circumferential weld but also ensures that the focal length from the circumferential X-ray machine to the surrounding films is uniform. This allows operators to easily calculate geometric blur using the focal length, a key parameter for judging the quality of the circumferential weld. Since the telescopic section has graduations for reading the extension length, the extension value can be directly read from the graduations after the telescopic section extends to the inner wall of the pressure expansion joint. By pre-measuring the fixed lengths of other components and their distances to the circumferential X-ray machine, the focal length can be obtained. This device is convenient to use, saves time and manpower, and eliminates the need for separate focal length measurement.

[0048] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A non-destructive testing device for the circumferential weld of a pressure expansion joint in a nuclear power plant, characterized in that, include: The bracket is detachably installed inside the pressure-bearing expansion joint and includes a mounting base located at the center of the pressure-bearing expansion joint; A circumferential X-ray machine is mounted on the mounting base and is used to emit X-rays radially toward the annular weld from the center position; A dark bag, surrounding the outside of the annular weld of the pressure expansion joint, and allowing X-rays to pass through the dark bag for holding unexposed film; The image quality meter is located at the annular slot within the pressure-bearing expansion joint ring; The bracket further includes multiple telescopic legs that are evenly distributed around the circumference of the mounting base and can extend and retract synchronously. The multiple telescopic legs are arranged in the same plane parallel to the plane where the circumferential weld is located. Each telescopic leg includes a fixed part and a telescopic part. One end of the fixed part is connected to the mounting base, and the other end of the fixed part extends radially. One end of the telescopic part is slidably mounted on the fixed part and can press and support the other end against the inner wall of the pressure-bearing expansion joint under the action of the driving device. The multiple fixed parts are of equal length, and each of the multiple telescopic parts is provided with a scale for measuring the extension length of the telescopic part.

2. The non-destructive testing device according to claim 1, characterized in that, Multiple image quality meters are arranged along the annular weld seam.

3. The non-destructive testing device according to claim 1, characterized in that, The fixed part is a hollow sleeve rod, and the telescopic part is a sliding rod, with one end of the sliding rod slidingly inserted into the hollow sleeve rod.

4. The non-destructive testing device according to claim 1, characterized in that, The drive device has multiple drive ends that drive the telescopic part to move synchronously.

5. The non-destructive testing device according to claim 4, characterized in that, The driving device also has a vertical moving end, the moving direction of which is perpendicular to the plane where the annular weld is located and passes through the center position of the pressure-bearing expansion joint; The driving device is provided with a push-pull linkage at the driving end. One end of the push-pull linkage is rotatably connected to the vertical moving end, and the other end is rotatably connected to the telescopic part. One end of the push-pull linkage is driven to move by the vertical moving end, and pulls the other end of the push-pull linkage to drive the telescopic part to move.

6. The non-destructive testing device according to claim 5, characterized in that, The connection point between the push-pull linkage and the telescopic part is near the end of the telescopic part that presses against and supports the inner wall of the pressure-bearing expansion joint.

7. The non-destructive testing device according to claim 5, characterized in that, The driving device has a vertical rod and a collar at the vertical moving end. The collar is slidably sleeved on the vertical rod, and one end of the push-pull connecting rod is rotatably connected to the collar. The collar drives one end of the push-pull connecting rod to move along the moving direction of the vertical moving end by sliding on the vertical rod.

8. The non-destructive testing device according to claim 7, characterized in that, A support frame is connected to the bottom of the vertical rod, and the support frame can be detachably installed on the circumferential X-ray instrument.

9. The non-destructive testing device according to claim 8, characterized in that, The support frame is a ring frame.

10. The non-destructive testing device according to claim 1, characterized in that, The telescopic part, which is supported by the inner wall of the pressure-bearing expansion joint, is also provided with a padding layer at one end.

Images