Method for detecting plate of plate heat exchanger of nuclear power station

Abstract

The invention provides a nuclear power station plate heat exchanger plate sheet detection method, which is based on a detection device, and comprises the following steps that a to-be-detected workpiece is fixed and sent to a detection station, and a control host controls a laser range finder to carry out scanning detection, the laser rangefinders feed back collected 3D point cloud data to the control host, the control host carries out three-dimensional reconstruction according to the collected 3D point cloud data, meanwhile, the thickness of the workpiece is calculated according to the distances to the workpiece measured by the two laser rangefinders, and the workpiece is detached after detection is completed. According to the method for detecting the plate of the plate heat exchanger of the nuclear power station, the two faces of the plate of the plate heat exchanger are scanned at the same time through the two laser rangefinders, three-dimensional modeling is carried out according to the information collected through scanning, the abrasion condition of the plate is accurately reflected, the abrasion problem of the plate is found in time, and the maintenance efficiency of the heat exchanger is improved.

Description

Technical Field

[0001] The present application relates to the technical field of rapid detection of plate wear and thickness of plate heat exchangers, and in particular to a method for detecting plate heat exchangers in nuclear power plants. Background Art

[0002] Plate heat exchanger is a widely used equipment in industrial production. It has advantages such as energy saving and high efficiency, but there are also some problems. One of the biggest problems is plate wear. Due to the working principle of plate heat exchanger, the plates inside it will be worn over time. When the plates are severely worn, the reliability of the heat exchanger will decrease, and even leakage will occur. Especially when the plate heat exchanger is used in nuclear power plants, its wear will seriously affect the normal operation of the nuclear power plant units.

[0003] Therefore, it is necessary to develop a plate detection method for plate heat exchangers in nuclear power plants. Summary of the invention

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

[0005] The technical solution adopted by the present application to solve its technical problem is: construct a plate detection method for a plate heat exchanger of a nuclear power plant, the detection method is based on a detection device, the detection device includes a detection station and a loading and unloading station, a slide rail is arranged between the detection station and the loading and unloading station, a locking bracket for fixing the workpiece to be detected is arranged on the slide rail, the locking bracket is slidably arranged on the slide rail, the detection station includes a laser rangefinder and a moving module, two laser rangefinders are arranged, the two laser rangefinders are symmetrically arranged on two opposite sides of the workpiece to be detected, the moving module drives the two laser rangefinders to move synchronously, the detection device includes a control host, the control host is connected to the moving module and the laser rangefinder; the detection method includes the following steps:

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

[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, so that the laser rangefinder moves and scans and detects the workpiece from both sides, and the laser rangefinder feeds back the collected 3D point cloud data to the control host;

[0008] S3, the control host realizes three-dimensional reconstruction of the workpiece surface based on the collected 3D point cloud data by using algorithms such as global fitting and Boolean segmentation, and accurately reproduces the appearance and surface details of the plate heat exchanger plate based on the three-dimensional model reconstruction, so as to detect the wear condition;

[0009] S4, according to the distance LA to the workpiece measured by two laser rangefinders 1 , LB 1 , calculate the thickness of the workpiece, the calculation formula is:

[0010] Workpiece thickness P = a-{LA-LA 1}-{LB-LB 1},

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

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

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

[0014] s01, fixing a standard plate with a thickness of a on the locking bracket at the loading and unloading station, and then moving the locking bracket along the slide rail to the inspection station;

[0015] s02, the control host controls the laser rangefinder to start, and at the same time the control host controls the movement of the mobile module, so that the laser rangefinder moves and scans the workpiece from both sides to obtain the distances LA and LB to the surface of the standard plate measured by the two laser rangefinders, and feeds them back to the control host for recording;

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

[0017] In some embodiments of the present application, the moving module includes an X-axis moving module for horizontal movement and a Z-axis moving module for vertical movement.

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

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

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

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

[0022] In some embodiments of the present application, a first sliding block cooperating with the sliding rail is disposed at the lower portion of the locking bracket.

[0023] In some embodiments of the present application, a positioning pin is provided at the lower portion of the locking bracket.

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

[0025] The implementation of this application has at least the following beneficial effects: This application proposes a method for detecting plates of plate heat exchangers in nuclear power plants, which uses two laser rangefinders to simultaneously scan both sides of the plate heat exchanger plates, and uses the information collected by the scan to perform three-dimensional modeling to accurately reflect its wear condition, thereby timely discovering plate wear problems and improving the maintenance efficiency of the heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0027] Figure 1 It is a structural schematic diagram of a plate detection device for a plate heat exchanger in a nuclear power plant provided in the present application.

[0028] Description of Figure Numbers:

[0029] Detection 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, detection bracket 420, laser rangefinder 430. DETAILED DESCRIPTION

[0030] In order to have a clearer understanding of the technical features, purposes and effects of the present application, the specific implementation methods of the present application are now described in detail with reference to the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0031] In the description of the present application, it should be understood that the terms "longitudinal", "lateral", "up", "down", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings or the orientations or positional relationships in which the products of the present application are usually placed when used. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0033] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0034] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] The main detection technologies currently include the following: (1) Visual technology: The application of visual technology is currently the most commonly used plate heat exchanger plate wear detection technology. By installing a camera in the plate heat exchanger pipeline, the plate is detected in real time so that the wear of the plate can be detected in time. Relevant research shows that visual technology can effectively detect the wear of the plate, but because the detection of visual technology depends on human visual ability, its accuracy depends on the proficiency of the operator. (2) Laser technology: Laser technology is a plate heat exchanger plate wear detection technology that has developed rapidly in recent years. It can accurately detect the plate by installing a laser transmitter and a receiver. Research shows that laser technology can effectively detect the wear of the plate, and has the advantages of simple operation and high accuracy. (3) Acoustic wave technology: Acoustic wave technology is a plate heat exchanger plate wear detection technology developed in recent years. It mainly detects the wear of the plate by installing an acoustic transmitter and a receiver. Research shows that acoustic wave technology can effectively detect the wear of the plate, and can detect wear with a smaller depth, so it has good application prospects. (4) Magnetic resonance technology: Magnetic resonance technology is a relatively mature plate heat exchanger plate wear detection technology developed abroad. It can detect the wear of the plate by installing a magnetic resonance instrument. Studies have shown that magnetic resonance technology can effectively detect the wear of the plate with high accuracy, so it has been widely used abroad. However, none of the above methods provide a method for using a three-dimensional model to conduct in-depth analysis of the collected data, achieve real-time monitoring, and display the thickness changes of the workpiece and the three-dimensional model measurement results in many aspects.

[0036] The present application provides a plate detection method for a plate heat exchanger in a nuclear power plant, and the detection method is based on a detection device. Specifically, Figure 1As shown, the detection device includes a detection station 10 and a loading and unloading station 20. In this embodiment, two loading and unloading stations 20 are provided. The two loading and unloading stations 20 are symmetrically arranged on both sides of the detection station 10. Two loading and unloading stations 20 are provided. The two loading and unloading stations 20 can be used together to realize manual loading when measuring the workpiece, thereby improving the measurement efficiency. A slide rail 300 is provided between the detection station 10 and the loading and unloading station 20. A locking bracket 200 for fixing the workpiece 100 to be detected is provided on the slide rail 300. A first slider 230 matching the slide rail 300 is provided at the lower part of the locking bracket 200. The locking bracket 200 is slidably arranged on the slide rail 300 through the first slider 230; at the same time, a positioning pin is also provided at the lower part of the locking bracket 200. When the locking bracket 200 reaches the detection station 10, the position can be locked by the pin to avoid affecting the detection result due to the sliding of the locking bracket 200 during the detection process. In order 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 detected is a plate of a plate heat exchanger, and a plurality of mounting holes are provided on the plate. A hook guide rail 210 is provided on the upper part of the locking bracket 200, and a second slider 211 is slidably provided on the hook guide rail 210, and a hook 212 is provided on the second slider 211, and the workpiece 100 is hung on the hook 212 through the mounting hole. In this application, since the hook 212 is slidably provided on the hook guide rail 210 through the second slider 211, the position of the hook 212 can be adjusted, and the hook 212 is provided on the second slider 211 in a detachable manner, which is convenient for replacement to adapt to workpieces of different sizes. In this embodiment, at least two hooks 212 are provided on the locking bracket 200 to better fix the workpiece 100, and after the workpiece 100 is hung, the workpiece can be well kept in a stable state under the action of gravity without deformation. Furthermore, the hook 212 is provided with an anti-unhooking structure, such as an inclined surface or a stepped design, which can effectively prevent the workpiece 100 from unhooking. The detection station 10 includes a bracket made of aluminum profiles, on which a moving module 410 is arranged, and an inverted U-shaped detection bracket 420 is connected to the end of the moving module 410. The two branches of the detection bracket 420 are respectively provided with laser rangefinders 430. When the workpiece 100 enters the detection station 10, the two laser rangefinders 430 are symmetrically arranged on two opposite sides of the workpiece 100 to be detected. The mobile module 410 of this embodiment adopts an embedded slide, and its structure is fully enclosed to prevent dust or other foreign matter from entering. It has high positioning accuracy and its repeated positioning accuracy is ±0.01mm. Furthermore, the mobile module 410 includes an X-axis mobile module for horizontal movement and a Z-axis mobile module for vertical movement. The mobile 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 comprehensive 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 provided with a processing CPU and a display screen to perform data processing and display the processing results.

[0037] The plate detection method of the nuclear power plant plate heat exchanger of the present 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 mobile module 410 to move, so that the laser rangefinder 430 moves and scans and detects the workpiece 100 from both sides, and the laser rangefinder 430 feeds back the collected 3D point cloud data to the control host;

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

[0041] S4, the distance LA to the workpiece 100 measured by the two laser range finders 430 1 , LB 1 , calculate the thickness of the workpiece 100, the calculation formula is:

[0042] The thickness of the workpiece 100 P = a-{LA-LA 1}-{LB-LB 1},

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

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

[0045] The loading and unloading operations in the above steps S1 and S5 can be performed manually, or corresponding automatic loading and unloading devices can be provided to automatically load and unload materials by machines instead of manual work.

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

[0047] s01, fix the standard plate with a thickness of a 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;

[0048] s02, the control host controls the laser rangefinder 430 to start, and at the same time controls the mobile module 410 to move, so that the laser rangefinder 430 moves and scans the workpiece 100 from both sides, obtains the distances LA and LB to the surface of the standard plate measured by the two laser rangefinders 430, and feeds them back to the control host for recording;

[0049] s03. 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 standard plate is unloaded at the loading and unloading station 20.

[0050] Furthermore, in the present application, the principle of detecting the thickness of the workpiece 100 is as follows: using a double-headed shooting measurement method, two laser rangefinders 430 are symmetrically installed to measure the standard sheet or workpiece 100 in the middle, and a standard sheet with a thickness of a is used for measurement in advance to obtain the distances LA and LB from the two laser rangefinders 430 to the standard sheet, and then the workpiece 100 is measured to obtain the distances LA from the two laser rangefinders 430 to the workpiece 100. 1 , LB 1 , then the thickness of the workpiece 100 P = a-{LA-LA 1}-{LB-LB 1 At the same time, a comparison ratio is also provided for the detection of the standard film, which is convenient for comparative observation.

[0051] In order to ensure the accuracy of the distance measurement from the two laser rangefinders 430 to the workpiece 100, the control host uses a feature point matching algorithm and a global fitting algorithm to achieve accurate measurement, including but not limited to a Fourier series fitting algorithm and a sin sum function fitting algorithm: determine 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 the parameters A, ω, φ, and B so that the sum of the square errors between the fitting function and the original data is minimized.

[0052] The present application also realizes the rapid identification of surface defects of plate heat exchanger plates based on 3D model reconstruction. Specifically, the 3D point cloud data collected by the laser rangefinder 430 is converted into a 2D image using a projection transformation algorithm, so that defect detection can be convenient and intuitive. The projection transformation is a transformation in 3D space. Therefore, 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 nuclear power plant plate heat exchanger plate detection method of the present application has the functions of automated scanning, three-dimensional reconstruction, thickness identification, and precise measurement, realizing the spatial three-dimensional detection technology of the plate heat exchanger plate, and adding a panoramic image display function to increase the visibility and observation convenience of the plate, and at the same time has a 3D comparison display function for easy comparative observation. The detection method of the present application can accurately measure the thickness dimension information of plates of different specifications, and automatically calculate and count the thinning area of ​​the plate, to realize a panoramic image display of the plate.

[0054] The above embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present application. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the present application, the above-mentioned technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the present application. Therefore, all equivalent changes and modifications made to the scope of the claims of the present application should belong to the scope covered by the claims of the present application.

Claims

1. A plate detection method for a plate heat exchanger in a nuclear power plant, characterized in that: The detection method is based on a detection device, the detection device comprising a detection station (10) and a loading and unloading station (20), a slide rail (300) being arranged between the detection station (10) and the loading and unloading station (20), a locking bracket (200) being arranged on the slide rail (300) for fixing a workpiece (100) to be detected, the locking bracket (200) being slidably arranged on the slide rail (300), the detection station (10) comprising a laser rangefinder (430) and a moving module (410), two laser rangefinders (430) being arranged, the two laser rangefinders (430) being symmetrically arranged on two opposite sides of the workpiece (100) to be detected, the moving module (410) driving the two laser rangefinders (430) to move synchronously, the detection device comprising a control host, the control host being connected to the moving module (410) and the laser rangefinder (430); the detection method comprises the following steps: S1, fixing the workpiece (100) to be inspected on the locking bracket (200) at the loading and unloading station (20), and then moving the locking bracket (200) along the slide rail (300) to the inspection station (10); S2, 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 the laser rangefinder (430) feeds back the collected 3D point cloud data to the control host; S3, the control host realizes three-dimensional reconstruction of the surface of the workpiece (100) based on the collected 3D point cloud data by using algorithms such as global fitting and Boolean segmentation, and accurately reproduces the appearance and surface details of the plate of the plate heat exchanger based on the three-dimensional model reconstruction, so as to detect the wear condition; S4. Calculate the thickness of the workpiece (100) according to the distances LA1 and LB1 to the workpiece (100) measured by the two laser rangefinders (430). The calculation formula is: The thickness of the workpiece (100) P = a-{LA-LA1}-{LB-LB1}, Wherein a is the thickness of the standard plate, LA and LB are the distances 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 plate detection method for a plate heat exchanger in a nuclear power plant according to claim 1, characterized in that: The detection method further includes a pre-step of obtaining LA and LB parameters, and the pre-step includes the following sub-steps: s01, fixing a standard plate with a thickness of a on the locking bracket (200) at the loading and unloading station (20), and then moving the locking bracket (200) along the slide rail (300) to the inspection station (10); s02, the control host controls the laser rangefinder (430) to start, and at the same time the control host controls the moving module (410) to move, so that the laser rangefinder (430) moves and scans the workpiece (100) from both sides, obtains the distances LA and LB to the surface of the standard plate measured by the two laser rangefinders (430), and feeds them back to the control host for recording; s03. 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 standard plate is unloaded at the loading and unloading station (20).

3. The plate detection method for a plate heat exchanger in a nuclear power plant according to claim 2, characterized in that: The moving module (410) includes an X-axis moving module for horizontal movement and a Z-axis moving module for vertical movement.

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

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

6. The plate detection method for a plate heat exchanger in a nuclear power plant according to claim 5, characterized in that: A hook guide rail (210) is arranged on the upper part of the locking bracket (200), a second sliding block (211) is slidably arranged on the hook guide rail (210), and the hook (212) is arranged on the second sliding block (211).

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

8. The plate detection method for a plate heat exchanger in a nuclear power plant according to claim 2 or 5, characterized in that: The lower part of the locking bracket (200) is provided with a first sliding block (230) which matches with the sliding rail (300).

9. The plate detection method for a plate heat exchanger in a nuclear power plant according to claim 8, characterized in that: The lower part of the locking bracket (200) is provided with a latch for positioning.

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

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