Nuclear Power Plant Plate Heat Exchanger Plate Testing Method

Abstract

This application proposes a method for inspecting plates in a nuclear power plant plate heat exchanger. The method, based on an inspection device, includes the following steps: fixing the workpiece to be inspected and placing it at the inspection station; controlling a laser rangefinder to perform scanning inspection; the laser rangefinder feeding back the collected 3D point cloud data to the control host; the control host performing 3D reconstruction based on the collected 3D point cloud data; and simultaneously calculating the workpiece thickness based on the distances measured by the two laser rangefinders; and finally, unloading the workpiece after inspection. This application proposes a method for inspecting plates in a nuclear power plant plate heat exchanger by simultaneously scanning both sides of the plate heat exchanger using two laser rangefinders, and using the information collected from these scans to create a 3D model, accurately reflecting the wear condition, thereby timely detection of plate wear problems and improving the maintenance efficiency of the heat exchanger.

Description

Technical Field

[0001] This application relates to the technical field of rapid detection of wear and thickness of plate heat exchanger plates, specifically to a method for detecting plate heat exchanger plates in nuclear power plants. Background Technology

[0002] Plate heat exchangers are widely used in industrial production, offering advantages such as energy saving and high efficiency. However, they also present some problems, the most significant being plate wear. Due to the working principle of plate heat exchangers, the internal plates wear down over time. When plate wear becomes severe, it can lead to decreased reliability and even leaks. This is particularly problematic when plate heat exchangers are used in nuclear power plants, where wear can seriously affect the normal operation of the nuclear power plant units.

[0003] Therefore, it is necessary to develop a method for testing the plates of nuclear power plant plate heat exchangers. Summary of the Invention

[0004] In view of the problems existing in the prior art, this application provides a method for detecting the plates of a nuclear power plant plate heat exchanger, so as to accurately reflect the wear condition of the plates of the nuclear power plant plate heat exchanger.

[0005] The technical solution adopted by this application to solve its technical problem is as follows: A method for inspecting plates in a nuclear power plant plate heat exchanger is constructed. The method is based on an inspection device, which includes an inspection station and a loading / unloading station. A slide rail is provided between the inspection station and the loading / unloading station. A locking bracket for fixing the workpiece to be inspected is provided on the slide rail. The locking bracket is slidably mounted on the slide rail. The inspection station includes a laser rangefinder and a moving module. Two laser rangefinders are provided, symmetrically arranged on two opposite sides of the workpiece to be inspected. The moving module drives the two laser rangefinders to move synchronously. The inspection device includes a control host connected to the moving module and the laser rangefinders. The inspection method includes the following steps:

[0006] S1. Fix the workpiece to be inspected on the locking bracket at the loading and unloading station, and then move the locking bracket to the inspection station along the slide rail;

[0007] S2. The control host controls the laser rangefinder to start, and at the same time, the control host controls the movement of the mobile module to move the laser rangefinder and scan and detect the workpiece from both sides. The laser rangefinder feeds back the collected 3D point cloud data to the control host.

[0008] S3. The control host uses algorithms such as global fitting and Boolean segmentation to realize the three-dimensional reconstruction of the workpiece surface based on the collected 3D point cloud data. Based on the three-dimensional model reconstruction, the appearance and surface details of the plate heat exchanger plates are accurately reproduced so as to detect wear.

[0009] S4. Calculate the thickness of the workpiece based on the distances LA1 and LB1 measured by the two laser rangefinders. The calculation formula is as follows:

[0010] Workpiece thickness P = a - {LA - LA1} - {LB - LB1}

[0011] Where 'a' is the thickness of the standard plate, and LA and LB are the distances to the standard plate measured by the two laser rangefinders;

[0012] S5. After the inspection is completed, move the locking bracket along the slide rail to the loading and unloading station, and unload the workpiece at the loading and unloading station.

[0013] In some embodiments of this application, the detection method further includes a pre-step to obtain LA and LB parameters, which includes the following sub-steps:

[0014] s01. At the loading and unloading station, a standard plate of thickness a is fixed on the locking bracket, and then the locking bracket is moved to the detection station along the slide rail;

[0015] s02. The control host controls the laser rangefinder to start, and at the same time, the control host controls the movement of the moving module to move the laser rangefinder and scan and detect the workpiece from both sides, obtain the distances LA and LB to the surface of the standard plate measured by the two laser rangefinders, and feed them back to the control host for recording.

[0016] s03. After the inspection is completed, move the locking bracket along the slide rail to the loading and unloading station, and unload the standard plate at the loading and unloading station.

[0017] In some embodiments of this application, the moving module includes a horizontally moving X-axis moving module and a vertically moving Z-axis moving module.

[0018] In some embodiments of this application, the testing station includes an inverted U-shaped testing bracket, the testing bracket is connected to the mobile module, and the laser rangefinder is symmetrically arranged on two branches of the testing bracket.

[0019] In some embodiments of this application, the locking bracket includes at least two hooks on which the workpiece is hung.

[0020] In some embodiments of this application, the upper part of the locking bracket is provided with a hook guide rail, a second slider is slidably disposed on the hook guide rail, and the hook is disposed on the second slider.

[0021] In some embodiments of this application, the vertical side of the locking bracket is provided with a push handle.

[0022] In some embodiments of this application, the lower part of the locking bracket is provided with a first slider that cooperates with the slide rail.

[0023] In some embodiments of this application, the lower part of the locking bracket is provided with a positioning pin.

[0024] In some embodiments of this application, the detection device includes two loading and unloading stations, which are symmetrically arranged on both sides of the detection station.

[0025] Implementing this application has at least the following beneficial effects: This application proposes a plate inspection method for plate heat exchangers in nuclear power plants. The method involves simultaneously scanning both sides of the plate heat exchanger plates using two laser rangefinders, and using the information collected from the scans to create a three-dimensional model that accurately reflects the wear condition of the plates, thereby enabling timely detection of plate wear problems and improving the maintenance efficiency of the heat exchanger. Attached Figure Description

[0026] The present application will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0027] Figure 1 This is a schematic diagram of the plate detection device for nuclear power plant plate heat exchangers provided in this application.

[0028] Explanation of icon numbers:

[0029] Inspection station 10, loading and unloading station 20, workpiece 100, locking bracket 200, hook guide rail 210, second slider 211, hook 212, push handle 220, first slider 230, slide rail 300, moving module 410, inspection bracket 420, laser rangefinder 430. Detailed Implementation

[0030] To provide a clearer understanding of the technical features, objectives, and effects of this application, the specific embodiments of this application are now described in detail with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0031] In the description of this application, it should be understood that the terms "longitudinal", "lateral", "up", "down", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application 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. Therefore, they should not be construed as limitations on this application.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0035] The main detection techniques currently include the following: (1) Visual technology: Visual technology is currently the most commonly used technology for detecting the wear of plate heat exchanger plates. By installing a camera inside the plate heat exchanger pipes, the plates are detected in real time to promptly detect the wear of the plates. Studies have shown that visual technology can effectively detect the wear of the plates, but since the detection of visual technology depends on human visual ability, its accuracy depends on the operator's proficiency. (2) Laser technology: Laser technology is a rapidly developing technology for detecting the wear of plate heat exchanger plates in recent years. It can accurately detect the plates by installing a laser emitter and receiver. Studies have shown that laser technology can effectively detect the wear of the plates and has the advantages of simple operation and high accuracy. (3) Acoustic technology: Acoustic technology is a plate heat exchanger plate wear detection technology that has been developed in recent years. It mainly detects the wear of the plates by installing an acoustic emitter and receiver. Studies have shown that acoustic technology can effectively detect the wear of the plates and can detect wear with a small depth, so it has good application prospects. (4) Magnetic Resonance Technology: Magnetic resonance technology is a relatively mature technology for detecting the wear of plate heat exchanger plates, developed abroad. It can detect the wear of the plates by installing a magnetic resonance instrument. Studies have shown that magnetic resonance technology can effectively detect the wear of plates with high accuracy, and therefore it has been widely used abroad. However, none of the above methods provide a way to use a three-dimensional model to perform in-depth analysis of the collected data, achieve real-time monitoring, and comprehensively display the thickness changes of the workpiece and the measurement results of the three-dimensional model.

[0036] This application provides a method for inspecting the plates of a plate heat exchanger in a nuclear power plant. This method is based on a testing device. Specifically, as shown... Figure 1As shown, the testing device includes a testing station 10 and a loading / unloading station 20. In this embodiment, two loading / unloading stations 20 are provided, symmetrically arranged on both sides of the testing station 10. These two stations can be used in conjunction to enable manual loading during workpiece measurement, improving measurement efficiency. A slide rail 300 is provided between the testing station 10 and the loading / unloading station 20. A locking bracket 200 for fixing the workpiece 100 to be tested is provided on the slide rail 300. A first slider 230 cooperating with the slide rail 300 is provided at the lower part of the locking bracket 200. The locking bracket 200 is slidably mounted on the slide rail 300 via the first slider 230. Simultaneously, a positioning pin is also provided at the lower part of the locking bracket 200. When the locking bracket 200 reaches the testing station 10, its position can be locked by the pin, preventing slippage of the locking bracket 200 during testing and thus avoiding affecting the testing results. To facilitate pushing the locking bracket 200, a push handle 220 is provided on the vertical side of the locking bracket 200 in this embodiment. It should be noted that the workpiece 100 to be tested is a plate heat exchanger plate, and the plate has multiple mounting holes. A hook guide rail 210 is provided on the upper part of the locking bracket 200, and a second slider 211 is slidably mounted on the hook guide rail 210. A hook 212 is provided on the second slider 211, and the workpiece 100 is hung on the hook 212 through the mounting holes. In this application, since the hook 212 is slidably mounted on the hook guide rail 210 via the second slider 211, the position of the hook 212 can be adjusted. Furthermore, the hook 212 is detachably mounted on the second slider 211 for easy replacement to accommodate workpieces of different sizes. In this embodiment, the locking bracket 200 is provided with at least two hooks 212 to better fix the workpiece 100. After the workpiece 100 is hung, it can maintain a stable state under the action of gravity and will not deform. Furthermore, the hook 212 has an anti-disengagement structure, such as an inclined surface or a stepped design, which can effectively prevent the workpiece 100 from disengaging. The inspection station 10 includes a bracket made of aluminum profile, on which a moving module 410 is installed. The end of the moving module 410 is connected to an inverted U-shaped inspection bracket 420. Laser rangefinders 430 are respectively installed on the two branches of the inspection bracket 420. When the workpiece 100 enters the inspection station 10, the two laser rangefinders 430 are symmetrically arranged on the two opposite sides of the workpiece 100 to be inspected. The moving module 410 in this embodiment adopts an embedded slide table with a fully enclosed structure to prevent dust or other foreign objects from entering. It has high positioning accuracy, with a repeatability of ±0.01mm. Furthermore, the moving module 410 includes a horizontally moving X-axis moving module and a vertically moving Z-axis moving module. The moving module 410 can drive the detection bracket 420 to move along the X-axis and Z-axis directions, and the laser rangefinder 430 performs a full scan of the workpiece 100.The detection device also includes a control host, which is connected to the mobile module 410 and the laser rangefinder 430. The control host is equipped with a processing CPU and a display screen to process data and display the processing results.

[0037] The method for testing the plates of a nuclear power plant plate heat exchanger according to this application specifically includes the following steps:

[0038] S1. Fix the workpiece 100 to be inspected on the locking bracket 200 at the loading and unloading station 20, and then move the locking bracket 200 to the inspection station 10 along the slide rail 300.

[0039] S2. The control host controls the laser rangefinder 430 to start, and at the same time controls the movement of the moving module 410 to move the laser rangefinder 430 and scan and detect the workpiece 100 from both sides. The laser rangefinder 430 feeds back the collected 3D point cloud data to the control host.

[0040] S3. The control host uses algorithms such as global fitting and Boolean segmentation to realize the three-dimensional reconstruction of the surface of the workpiece 100 based on the collected 3D point cloud data. Based on the three-dimensional model reconstruction, the appearance and surface details of the plate heat exchanger plates are accurately reproduced so as to detect wear.

[0041] S4. Based on the distances LA1 and LB1 to the workpiece 100 measured by the two laser rangefinders 430, calculate the thickness of the workpiece 100 using the following formula:

[0042] The thickness P of the workpiece is 100 mm.

[0043] Where 'a' is the thickness of the standard plate, and LA and LB are the distances to the standard plate measured by the two laser rangefinders 430;

[0044] S5. After the inspection is completed, move the locking bracket 200 along the slide rail 300 to the loading and unloading station 20. Unload the workpiece 100 at the loading and unloading station 20. At the same time, according to the inspection results, divide the unloaded workpiece 100 into qualified products and unqualified products, and place them in categories.

[0045] The loading and unloading operations in steps S1 and S5 above can be performed manually, or an automatic loading and unloading device can be set up to replace manual loading and unloading.

[0046] In addition, in order to calculate the thickness of workpiece 100, the detection method of this application also includes a preliminary step of obtaining LA and LB parameters, which includes the following sub-steps:

[0047] s01. At the loading and unloading station 20, fix the standard plate with thickness a on the locking bracket 200, and then move the locking bracket 200 to the inspection station 10 along the slide rail 300.

[0048] s02. The host controller starts the laser rangefinder 430 and simultaneously controls the movement of the moving module 410, so that the laser rangefinder 430 moves and scans the workpiece 100 from both sides to obtain the distances LA and LB to the standard plate surface measured by the two laser rangefinders 430, and feeds them back to the host controller for recording.

[0049] s03. After the inspection is completed, move the locking bracket 200 along the slide rail 300 to the loading and unloading station 20, and unload the standard plate at the loading and unloading station 20.

[0050] Furthermore, in this application, the principle for detecting the thickness of workpiece 100 is as follows: A dual-head, through-beam measurement method is used, with two laser rangefinders 430 symmetrically installed to measure the intermediate standard piece or workpiece 100. A standard piece of thickness 'a' is used beforehand to measure the distances LA and LB from the two laser rangefinders 430 to the standard piece. Then, the workpiece 100 is measured to obtain the distances LA1 and LB1 from the two laser rangefinders 430 to the workpiece 100. Therefore, the thickness P of workpiece 100 is calculated as P = a - {LA - LA1} - {LB - LB1}. Simultaneously, the measurement of the standard piece provides a comparative example for easy observation.

[0051] To ensure the accuracy of distance measurement between the two laser rangefinders 430 and the workpiece 100, the control host utilizes feature point matching algorithms and global fitting algorithms to achieve accurate measurement. These include, but are not limited to, Fourier series fitting algorithms and sin function fitting algorithms: determining the form of the sin function, i.e., y = Asin(ωx + φ) + B, where A is the amplitude, ω is the angular frequency, φ is the phase difference, and B is the y-axis offset. The least squares method is used to determine the values ​​of parameters A, ω, φ, and B, minimizing the sum of squared errors between the fitted function and the original data.

[0052] This application also enables rapid identification of surface defects in plate heat exchanger plates based on 3D model reconstruction. Specifically, a projection transformation algorithm is used to convert the 3D point cloud data collected by the laser rangefinder 430 into a 2D image, which facilitates convenient and intuitive defect detection. Since projection transformation is a 3D transformation, for a 2D image, the last original coordinate z is always 1, and the last parameter of the transformation matrix is ​​also always 1.

[0053] The plate inspection method for nuclear power plant plate heat exchangers disclosed in this application features automated scanning, 3D reconstruction, thickness identification, and precise measurement functions. It realizes 3D spatial inspection technology for plate heat exchanger plates and adds a panoramic image display function to enhance the visibility and ease of observation of the plates. It also has a 3D comparison display function for easy comparison and observation. The inspection method of this application can accurately measure the thickness dimensions of plates of different specifications and automatically calculate and statistically analyze the thinned area of ​​the plates, thereby realizing a panoramic image display of the plates.

[0054] The above embodiments merely illustrate specific implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this application's patent. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of this application, and can also make several modifications and improvements, all of which fall within the protection scope of this application. Therefore, any equivalent transformations and modifications made within the scope of the claims of this application should be covered by the claims of this application.

Claims

1. A method for testing plates in a nuclear power plant plate heat exchanger, characterized in that, The detection method is based on a detection device, which includes a detection station (10) and a loading / unloading station (20). A slide rail (300) is provided between the detection station (10) and the loading / unloading station (20). A locking bracket (200) for fixing the workpiece (100) to be detected is provided on the slide rail (300). The locking bracket (200) is slidably disposed on the slide rail (300). The detection station (10) includes a laser rangefinder (430) and a moving module (410). There are two laser rangefinders (430), which are symmetrically disposed on two opposite sides of the workpiece (100) to be detected. The moving module (410) drives the two laser rangefinders (430) to move synchronously. The detection device includes a control host, which is connected to the moving module (410) and the laser rangefinders (430). The detection method includes the following steps: S1. Fix the workpiece (100) to be inspected on the locking bracket (200) at the loading and unloading station (20), and then move the locking bracket (200) to the inspection station (10) along the slide rail (300). S2. The control host controls the laser rangefinder (430) to start, and at the same time the control host controls the movement of the mobile module (410) to move the laser rangefinder (430) and scan the workpiece (100) from both sides. The laser rangefinder (430) feeds back the collected 3D point cloud data to the control host. S3. The control host uses global fitting algorithm and Boolean segmentation algorithm to realize the three-dimensional reconstruction of the surface of the workpiece (100) based on the collected 3D point cloud data. Based on the three-dimensional model reconstruction, the appearance and surface details of the plate heat exchanger plates are accurately reproduced so as to detect wear. S4. The distance to the workpiece (100) measured by the two laser rangefinders (430) , The thickness of the workpiece (100) is calculated using the following formula: Workpiece (100) thickness P , Where 'a' is the standard plate thickness. The distance to the standard plate measured by two laser rangefinders (430); S5. After the inspection is completed, the locking bracket (200) is moved along the slide rail (300) to the loading and unloading station (20), and the workpiece (100) is unloaded at the loading and unloading station (20).

2. The method for detecting plates in a nuclear power plant plate heat exchanger according to claim 1, characterized in that, The detection method also includes obtaining The parameter pre-processing steps include the following sub-steps: s01. At the loading and unloading station (20), a standard plate with a thickness of a is fixed on the locking bracket (200), and then the locking bracket (200) is moved to the inspection station (10) along the slide rail (300). s02. The control host controls the laser rangefinder (430) to start, and at the same time, the control host controls the movement module (410) to move, so that the laser rangefinder (430) moves and scans and detects the workpiece (100) from both sides, and obtains the distance to the surface of the standard plate measured by the two laser rangefinders (430). And the data is fed back to the control host and recorded. s03. After the inspection is completed, move the locking bracket (200) along the slide rail (300) to the loading and unloading station (20) and unload the standard plate at the loading and unloading station (20).

3. The method for detecting plates in a nuclear power plant plate heat exchanger according to claim 2, characterized in that, The moving module (410) includes a horizontally moving X-axis moving module and a vertically moving Z-axis moving module.

4. The method for detecting plates in a nuclear power plant plate heat exchanger according to claim 2 or 3, characterized in that, The testing station (10) includes an inverted U-shaped testing bracket (420), which is connected to the mobile module (410). The laser rangefinder (430) is symmetrically arranged on two branches of the testing bracket (420).

5. The method for detecting plates in a nuclear power plant plate heat exchanger according to claim 2, characterized in that, The locking bracket (200) includes at least two hooks (212), on which the workpiece (100) is hung.

6. The method for detecting plates in a nuclear power plant plate heat exchanger according to claim 5, characterized in that, The upper part of the locking bracket (200) is provided with a hook guide rail (210), and a second slider (211) is slidably provided on the hook guide rail (210). The hook (212) is provided on the second slider (211).

7. The method for testing plates in a nuclear power plant plate heat exchanger according to claim 2 or 5, characterized in that, The vertical side of the locking bracket (200) is provided with a push handle (220).

8. The method for testing plates in a nuclear power plant plate heat exchanger according to claim 2 or 5, characterized in that, The lower part of the locking bracket (200) is provided with a first slider (230) that cooperates with the slide rail (300).

9. The method for detecting plates in a nuclear power plant plate heat exchanger according to claim 8, characterized in that, The locking bracket (200) is provided with a positioning pin at its lower part.

10. The method for detecting plates in a nuclear power plant plate heat exchanger according to claim 2, characterized in that, The detection device includes two loading and unloading stations (20), which are symmetrically arranged on both sides of the detection station (10).

Images