A mine scraper magnetic flaw detection device and a flaw detection method thereof

Abstract

This invention discloses a magnetic flaw detection device and method for a mining scraper conveyor. The device includes a scraper conveyor body with a flaw detection assembly mounted on it. The flaw detection assembly includes a fixed plate mounted on the scraper conveyor body. Two fixed blocks are fixedly connected to the lower end of the fixed plate. A rotating shaft is rotatably connected between adjacent sides of the two fixed blocks, passing through the two fixed blocks. Two rectangular blocks are fixedly connected to the rotating shaft, and inclined plates are fixedly connected to the upper and lower sides of each of the two rectangular blocks. This invention utilizes a magnetic flux sensor array for flaw detection of the scraper and chain of a scraper conveyor, enabling real-time, online, non-contact, and non-destructive flaw detection. Furthermore, it incorporates modern industrial internet, cloud storage, cloud computing, and artificial intelligence technologies, enabling not only real-time, online, non-contact, continuous, and passive flaw detection during scraper conveyor operation, but also defect identification, diagnosis, and alarm functions without human intervention.

Description

Technical Field

[0001] This invention relates to the field of non-destructive testing technology, and in particular to a magnetic flaw detection device and method for a mining scraper conveyor. Background Technology

[0002] A scraper conveyor is a conveying device that uses a scraper chain to transport bulk materials within a trough. In coal mining faces, scraper conveyors not only transport coal and materials but also serve as the running track for the coal mining machine, making them an indispensable piece of equipment in modern coal mining processes. Continuous operation of the scraper conveyor is crucial for normal production; otherwise, the entire coal mining face will be shut down, leading to significant economic losses. During continuous operation in a fully mechanized mining face, the scraper conveyor chain is prone to wear, stretching, and even breakage and jamming. The scrapers are also susceptible to wear, misalignment, and even chain drop and detachment from the trough. Failure to promptly identify and address these potential safety hazards, and to replace, repair, and adjust them in a timely manner, can easily lead to work stoppages and require more personnel and time to locate the faulty unit, location, symptoms, and causes.

[0003] Because the objects being tested by scraper conveyors have special shapes, complex operating conditions, and diverse defect types, there are currently no online detection devices during the operation of scraper conveyors, and manual inspection is still relied upon. This is completely incompatible with the current level of coal mining automation and also hinders the future development of unmanned coal mining. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a magnetic flaw detection device and method for mining scraper conveyors. This invention utilizes a magnetic flux sensor array for flaw detection of the scraper and chain of the scraper conveyor, enabling real-time, online, non-contact, and non-destructive flaw detection. Furthermore, it incorporates modern industrial internet, cloud storage, cloud computing, and artificial intelligence technologies, enabling not only real-time, online, non-contact, continuous, and passive flaw detection during scraper conveyor operation, but also defect identification, diagnosis, and alarm functions without human intervention.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A magnetic flaw detection device for a mining scraper conveyor includes a scraper conveyor body. A flaw detection component is installed on the scraper conveyor body. The flaw detection component includes a fixed plate disposed on the scraper conveyor body. Two fixed blocks are fixedly connected to the lower end of the fixed plate. A rotating shaft is rotatably connected between the adjacent sides of the two fixed blocks. The rotating shaft passes through the two fixed blocks. Two rectangular blocks are fixedly connected to the rotating shaft. Inclined plates are fixedly connected to the upper and lower sides of the two rectangular blocks. A connecting rod is fixedly connected to the adjacent sides of the two inclined plates. A linear array of 2-4 magnetic flux sensors is provided at the lower end of the lower inclined plate.

[0007] Preferably, the fixing plate is provided with positioning holes, both fixing blocks are provided with threaded grooves, both threaded grooves are threaded with second bolts, both second bolts are threaded with second nuts, and the left side of the scraper machine body is provided with two threaded holes that cooperate with the second bolts.

[0008] Preferably, the two inclined plates are provided with multiple adjustment ports, and a first bolt is provided in every two cooperating adjustment ports. The lower end of each first bolt is fixedly connected to the upper end of the corresponding magnetic flux sensor linear array. Multiple first nuts are provided between the two inclined plates, and the multiple first nuts are threadedly connected to the outer wall of the corresponding first bolt.

[0009] Preferably, the linear array of magnetic flux sensors includes a housing, in which multiple magnetic flux sensors are installed. A power cable gland and a network port gland are installed at the upper end of the housing, and an indicator light is installed at the upper end of the housing.

[0010] Preferably, the outer shell is composed of a bottom shell and a top shell, which are connected by screws. The outer shell is made of copper, and a sealing ring is provided between the bottom shell and the top shell.

[0011] Preferably, it also includes a multi-channel analog signal acquisition component and a speed measurement and positioning component. The multi-channel analog signal acquisition device uses an STM32F743 / 750 chip, which is based on Cortex-M7 and integrates a 16-bit sigma-delta ADC. The speed measurement and positioning component is an axis angle encoder or a comprehensive positioning system.

[0012] To achieve the above-mentioned objectives, the present invention also provides a flaw detection method for a magnetic flaw detection device for a mining scraper conveyor, comprising the following steps:

[0013] S1: Collect measurement data through network port or serial port, and arrange a specified number of measurement data into a two-dimensional array according to the position and magnetic flux sensor arrangement order, collectively referred to as the measurement array;

[0014] S2: Convert the measurement array into a grayscale image. The image width is the length of the measurement array taken along the longitudinal direction of the belt, and the image height is the number of magnetic flux sensors. To improve its resolution, the corresponding measurement data can be linearly interpolated. This image is collectively referred to as the measurement image or the scraper and chain magnetic image.

[0015] S3: Perform wavelet filtering on the measurement image to eliminate the influence caused by the background magnetic field;

[0016] S4: Perform multiple analyses and processing on the measured images to obtain faults and defects in the scraper and chain;

[0017] S5: For fault and defect measurement data, the center point coordinates, maximum value, minimum value, average value, standard deviation, area (number of pixels within the contour) and volume (grayscale integral value of pixels within the contour) are used as feature quantities of suspected defects.

[0018] S6: For defects identified during the suspected defect identification process, image similarity calculation can be performed with a series of defect images in the standard defect template library. Once the similarity reaches the standard limit, the defect type and level of the corresponding standard defect template can be determined.

[0019] S7: The computer system will then run automatically and output the flaw detection results and alarm signals as needed.

[0020] The present invention has the following beneficial effects:

[0021] 1. Compared with the prior art, the present invention, by arranging multiple magnetic flux sensors in a linear pattern and parallel to the scraper conveyor, can more accurately detect the leakage magnetic field and induced magnetic field generated by its faults and defects. It fully meets the flaw detection requirements based on the metal magnetic memory effect and magnetic anomaly detection. Its advantages compared with magnetic flux leakage flaw detection are that it does not require excitation, has better repeatability and stability, higher sensitivity, can detect smaller defects, as well as wear and corrosion, and its overall performance is greatly improved. It can not only detect existing defects, but also predict defects that have not yet occurred by detecting internal stress.

[0022] 2. Compared with existing technologies, it ensures that production safety management is always under control, and can detect the entire process of changes from minor defects to major defects, from changes in internal stress to the occurrence of defects. For the first time in non-destructive testing, it has both sensing and predictive capabilities, laying the foundation for the improvement of maintenance and repair planning, and is expected to significantly reduce accident rates, maintenance costs, and management costs.

[0023] 3. Compared with existing technologies, there is a more complete technical solution for scraper conveyor flaw detection. Its radiation-free, real-time, online, non-contact, and passive flaw detection method, as well as its computerized, intelligent, and unmanned operation mode, are more easily accepted by everyone. This creates the possibility for large-scale promotion and application in the future and the unmanned operation of coal mining, and has huge social and economic benefits.

[0024] 4. For the first time, a magnetic flux sensor was used, applying the principles of metal magnetic memory flaw detection and magnetic anomaly detection to the flaw detection of scraper conveyors, thus promoting technological progress and development in this field. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a magnetic flaw detection device for a mining scraper conveyor proposed in this invention;

[0026] Figure 2 for Figure 1 A side view diagram;

[0027] Figure 3 for Figure 1 Enlarged structural diagram at point A;

[0028] Figure 4 This is a diagram showing the internal structure of a linear array of magnetic flux sensors.

[0029] Figure 5 This is a diagram showing the external structure of a linear array of magnetic flux sensors.

[0030] Figure 6 This invention presents a data analysis and processing flowchart for amplified magnetic flaw detection in a mining scraper conveyor.

[0031] Figure 7 This is a block diagram of a multi-channel analog signal acquisition device based on STM32F743 / 750.

[0032] In the diagram: 1. Scraper conveyor body; 2. Magnetic flux sensor linear array; 3. Fixing plate; 4. Positioning hole; 5. Inclined plate; 6. Adjustment port; 7. First bolt; 8. Fixing block; 9. Second bolt; 10. Second nut; 11. Outer shell; 12. Mesh port gland; 13. Power cord gland; 14. Indicator light; 15. Connecting block; 16. First nut. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0034] Reference Figures 1-7A magnetic flaw detection device for a mining scraper conveyor includes a scraper conveyor body 1. A flaw detection component is installed on the scraper conveyor body 1. The flaw detection component includes a fixed plate 3 set on the scraper conveyor body 1. Two fixed blocks 8 are fixedly connected to the lower end of the fixed plate 3. A rotating shaft is rotatably connected between the adjacent sides of the two fixed blocks 8. The rotating shaft passes through the two fixed blocks 8. Two rectangular blocks are fixedly connected to the rotating shaft. Inclined plates 5 are fixedly connected to the upper and lower sides of the two rectangular blocks. A connecting rod is fixedly connected to the adjacent sides of the two inclined plates 5. A linear array of 2-4 magnetic flux sensors 2 is provided at the lower end of the lower inclined plate 5. In practical use, the two linear arrays of magnetic flux sensors 2 are installed above the scraper and the chain. The number of magnetic flux sensors is determined according to the length of the scraper and the width of the chain.

[0035] The fixed plate 3 is provided with positioning holes 4, and both fixed blocks 8 are provided with threaded grooves. The two threaded grooves are threaded with second bolts 9, and the two second bolts 9 are threaded with second nuts 10. The left side of the scraper machine body 1 is provided with two threaded holes that cooperate with the second bolts 9.

[0036] Among them, the two inclined plates 5 are provided with multiple adjustment ports 6, and each pair of matching adjustment ports 6 is provided with a first bolt 7. The lower end of each first bolt 7 is fixedly connected to the upper end of the corresponding magnetic flux sensor linear array 2. Multiple first nuts 16 are provided between the two inclined plates 5, and the multiple first nuts 16 are threadedly connected to the outer wall of the corresponding first bolt 7.

[0037] The magnetic flux sensor linear array 2 includes a housing 11, in which multiple magnetic flux sensors are installed. A power cable gland 13 and a network port gland 12 are installed at the top of the housing 11. An indicator light 14 is also installed at the top of the housing 11. The housing 11 is composed of a bottom shell and a top shell, which are connected by screws. The housing 11 is made of copper. A sealing ring is provided between the bottom shell and the top shell to form a waterproof sealed box.

[0038] This includes a multi-channel analog signal acquisition component and a speed measurement and positioning component. The multi-channel analog signal acquisition device uses an STM32F743 / 750 chip, which is based on Cortex-M7 and integrates a 16-bit sigma-delta ADC. The speed measurement and positioning component is an axis angle encoder or integrated positioning. The input shaft of the axis angle encoder is synchronously rotated with the drive wheel of the scraper conveyor through gear or belt drive to measure the current measurement position of the scraper and chain. Under the special operating environment requirements of underground, a driven shaft that can be mechanically synchronously rotated with the main drive motor shaft can be installed on the head of the scraper conveyor body 1. One end of the shaft is exposed outside the protective cover, and a circular magnetic sheet is attached to it. Then, a magnetic sensor can be used to realize speed measurement and positioning. The main function of the speed measurement and positioning component is to determine the sampling interval of the measurement data, ensure that the measurement data is collected at the specified distance to adapt to the linear speed of the wire rope, and at the same time, it is used to determine the location of defects.

[0039] The present invention also provides a flaw detection method for a magnetic flaw detection device for a mining scraper conveyor, comprising the following steps:

[0040] S1: Collect measurement data through network port or serial port, and arrange a specified number of measurement data into a two-dimensional array according to the position and magnetic flux sensor arrangement order, collectively referred to as the measurement array;

[0041] S2: Convert the measurement array into a grayscale image. The image width is the length of the measurement array taken along the longitudinal direction of the belt, and the image height is the number of magnetic flux sensors. To improve its resolution, the corresponding measurement data can be linearly interpolated. This image is collectively referred to as the measurement image or the magnetic image of the scraper and chain. It includes both the induced magnetic field of the scraper and chain and the leakage magnetic field generated by the defect.

[0042] S3: Perform wavelet filtering on the measurement image to eliminate the influence of the background magnetic field (e.g., external interference caused by the rotation or translation of motors, ferromagnetic metal parts, power cables, etc.).

[0043] S4: Perform multiple analyses and processing on the measured images to identify faults and defects in the scraper and chain. These processing steps include:

[0044] A) Extract the position information of the leading edge (rising edge or falling edge) of the scraper signal, and calculate whether the scraper has deflected on the horizontal plane;

[0045] B) Extract the maximum value of the scraper signal and its position information. If the maximum value changes at the same position in the horizontal direction, it can be determined whether the scraper has changed in the vertical direction, and thus determine whether it has been removed from the groove.

[0046] C) Extract the magnetic field signal at each position of the scraper and chain, and compare it with the no-fault and defect signals to determine whether the scraper and chain are worn, broken and deformed;

[0047] S5: For fault and defect measurement data, the center point coordinates, maximum value, minimum value, average value, standard deviation, area (number of pixels within the contour) and volume (grayscale integral value of pixels within the contour) are used as feature quantities of suspected defects. This processing process is called the suspected defect identification process.

[0048] S6: For defects identified during the suspected defect identification process, image similarity calculation can be performed with a series of defect images in the standard defect template library. Once the similarity reaches the standard limit, the defect type and level of the corresponding standard defect template can be determined. This is called the defect diagnosis process. The standard defect template library is obtained by combining simulation calculation, simulation experiment and field test results.

[0049] S7: The computer system will then run automatically and output the flaw detection results and alarm signals as needed.

[0050] The functional principle of this invention can be explained by the following operation: First, install the device on the scraper body 1, align the positioning hole 4 with the positioning block on the scraper body 1 so that the positioning block passes through the positioning hole 4, then rotate the two second bolts 9 so that the second bolts 9 enter the corresponding threaded holes. At this time, the installation of the flaw detection device is completed. Then rotate the second nut 10 so that the device is installed and tightened.

[0051] Then the positions of multiple (usually 2-4) linear arrays of magnetic flux sensors 2 can be adjusted. Rotate the first nut 16 so that the first nut 16 does not contact the inclined plate 5 below. At this time, the position of the linear array of magnetic flux sensors 2 can be adjusted by sliding the two first bolts 7 in the adjustment port 6. After the position is adjusted, rotate the first nut 16 again so that the lower end of the first nut 16 is tightly pressed together with the inclined plate 5 below. Then rotate the inclined plate 5 to a suitable angle (because the shaft is equipped with a damping bearing, the inclined plate 5 will not rotate when there is no external force).

[0052] A synchronous gear is installed on the drive wheel or driven wheel of the scraper conveyor, and a shaft angle encoder is installed on the gear shaft to achieve mechanical synchronous transmission with the scraper conveyor and control equidistant sampling, that is, the measurement data is collected once every 1mm movement of the scraper conveyor;

[0053] Using an STM32F743 or STM32F750 microcontroller chip, configuring its power supply, and providing an interface for the shaft angle encoder and an SDADC analog-to-digital converter (using its serial port directly, or converting the serial port to an Ethernet or Wi-Fi port as needed), a complete multi-channel analog signal acquisition device is constructed. This device can be directly installed inside housing 11 or a separate control box can be constructed. Connect the analog voltage output signal of the linear array 2 of the flux sensor in housing 11 to the SDADC interface of the multi-channel analog signal acquisition device, connect the shaft angle encoder / integrated positioning voltage pulse signal to the shaft angle encoder interface of the multi-channel analog signal acquisition device, and connect the digital output of the multi-channel analog signal acquisition device to a computer. This allows for flaw detection of the scraper and chain.

[0054] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A magnetic flaw detection device for a mining scraper conveyor, comprising a scraper conveyor body (1), characterized in that: The scraper machine body (1) is equipped with a flaw detection component. The flaw detection component includes a fixed plate (3) set on the scraper machine body (1). The lower end of the fixed plate (3) is fixedly connected to two fixed blocks (8). The adjacent sides of the two fixed blocks (8) are rotatably connected to a rotating shaft. The rotating shaft passes through the two fixed blocks (8). The rotating shaft is fixedly connected to two rectangular blocks. The upper and lower sides of the two rectangular blocks are fixedly connected to inclined plates (5). The adjacent sides of the two inclined plates (5) are fixedly connected to a connecting rod. The lower end of the lower inclined plate (5) is provided with a linear array (2) of 2-4 magnetic flux sensors.

2. The magnetic flaw detection device for a mining scraper conveyor according to claim 1, characterized in that: The fixing plate (3) is provided with positioning holes (4), and the two fixing blocks (8) are provided with threaded grooves. The two threaded grooves are threaded with second bolts (9), and the two second bolts (9) are threaded with second nuts (10). The left side of the scraper machine body (1) is provided with two threaded holes that cooperate with the second bolts (9).

3. The magnetic flaw detection device for a mining scraper conveyor according to claim 1, characterized in that: The two inclined plates (5) are provided with multiple adjustment ports (6), and a first bolt (7) is provided in each pair of matching adjustment ports (6). The lower end of each first bolt (7) is fixedly connected to the upper end of the corresponding magnetic flux sensor linear array (2). Multiple first nuts (16) are provided between the two inclined plates (5), and the multiple first nuts (16) are threadedly connected to the outer wall of the corresponding first bolt (7).

4. The magnetic flaw detection device for a mining scraper conveyor according to claim 1, characterized in that: The linear array of magnetic flux sensors (2) includes a housing (11), in which multiple magnetic flux sensors are installed. A power cable gland (13) and a network port gland (12) are installed at the upper end of the housing (11), and an indicator light (14) is installed at the upper end of the housing (11).

5. A magnetic flaw detection device for a mining scraper conveyor according to claim 4, characterized in that: The outer shell (11) is composed of a bottom shell and a top shell, which are connected by screws. The outer shell (11) is made of copper material, and a sealing ring is provided between the bottom shell and the top shell.

6. The magnetic flaw detection device for a mining scraper conveyor according to claim 1, characterized in that: It also includes a multi-channel analog signal acquisition component and a speed measurement and positioning component. The multi-channel analog signal acquisition device uses an STM32F743 / 750 chip, which is based on Cortex-M7 and integrates a 16-bit sigma-delta ADC. The speed measurement and positioning component is an axis angle encoder or a comprehensive positioning system.

7. A flaw detection method for a magnetic flaw detection device for a mining scraper conveyor, characterized in that, Includes the following steps: S1: Collect measurement data through network port or serial port, and arrange a specified number of measurement data into a two-dimensional array according to the position and magnetic flux sensor arrangement order, collectively referred to as the measurement array; S2: Convert the measurement array into a grayscale image. The image width is the length of the measurement array taken along the longitudinal direction of the belt, and the image height is the number of magnetic flux sensors. To improve its resolution, the corresponding measurement data can be linearly interpolated. This image is collectively referred to as the measurement image or the scraper and chain magnetic image. S3: Perform wavelet filtering on the measurement image to eliminate the influence caused by the background magnetic field; S4: Perform multiple analyses and processing on the measured images to obtain faults and defects in the scraper and chain; S5: For fault and defect measurement data, the center point coordinates, maximum value, minimum value, average value, standard deviation, area (number of pixels within the contour) and volume (grayscale integral value of pixels within the contour) are used as feature quantities of suspected defects. S6: For defects identified during the suspected defect identification process, image similarity calculation can be performed with a series of defect images in the standard defect template library. Once the similarity reaches the standard limit, the defect type and level of the corresponding standard defect template can be determined. S7: The computer system will then run automatically and output the flaw detection results and alarm signals as needed.

Images