A tank bottom plate detection device and a detection method

Abstract

The application provides a kind of storage tank bottom plate detection device and detection method, storage tank bottom plate detection device, comprising: first outer ring magnet, second outer ring magnet, inner ring magnet, annular excitation coil, isolation layer, multi-section annular receiving coil, hall element, the second outer ring magnet is sleeved on the outside of inner ring magnet, the first outer ring magnet is sleeved on the outside of second outer ring magnet, annular excitation coil is wound on the outside of second outer ring magnet and inner ring magnet, multi-section annular receiving coil is wound on the first outer ring magnet along the circumference of first outer ring magnet, isolation layer is installed between first outer ring magnet and second outer ring magnet, hall element is installed in isolation layer. Realize the organic fusion of magnetic flux leakage detection and electromagnetic ultrasonic guided wave detection technology. Single detection range is large, and it is convenient to check the area of large storage tank bottom plate comprehensively and quickly. Improve the detection efficiency of storage tank bottom plate, reduce the consumption of manpower and material resources.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of storage tank detection, and particularly relates to a storage tank bottom plate detection device and a detection method. BACKGROUND

[0002] Large oil storage tanks are major basic key equipment for guaranteeing oil and gas resources, and once corrosion occurs, not only the structural strength of the storage tank is reduced, but also a fire and explosion accident is caused in serious cases, causing huge economic losses. In order to ensure the safe operation of the storage tank, it is necessary to carry out regular shutdown maintenance on the storage tank in the actual operation process. At present, more and more attention is paid to the structural health detection and monitoring of the storage tank, and the storage tank bottom plate is the focus. At present, for the detection of the storage tank bottom plate, traditional detection methods such as magnetic flux leakage, longitudinal wave ultrasonic thickness measurement, eddy current detection and magnetic powder detection are generally used. These detection methods can only detect the plate surface below the sensor, and the single detection range is small and the efficiency is very low.

[0003] In actual work, it is difficult to comprehensively and quickly check the large-area storage tank bottom plate by using the above nondestructive testing methods. SUMMARY

[0004] The present application relates to the technical field of storage tank detection, and particularly relates to a storage tank bottom plate detection device and a detection method.

[0005] The technical scheme for solving the above technical problem is as follows: a storage tank bottom plate detection device, comprising: a first outer ring magnet, a second outer ring magnet, an inner ring magnet, a ring-shaped excitation coil, an isolation layer, a plurality of ring-shaped receiving coils, and a Hall element, the second outer ring magnet is sleeved outside the inner ring magnet, the first outer ring magnet is sleeved outside the second outer ring magnet, the ring-shaped excitation coil is wound outside the second outer ring magnet and the inner ring magnet, a plurality of ring-shaped receiving coils are wound on the first outer ring magnet along the circumference of the first outer ring magnet, the isolation layer is installed between the first outer ring magnet and the second outer ring magnet, and the Hall element is installed in the isolation layer.

[0006] The beneficial effects of the technical scheme are as follows: the corrosion detection of a large range of tank bottom plates can be realized without direct contact and ultrasonic coupling, the structure of the annular permanent magnet is reasonably designed, the annular excitation coil, the annular receiving coil and the Hall element are arranged, and the organic integration of the magnetic flux leakage detection and the electromagnetic ultrasonic guided wave detection technology is realized.The single detection range is large, the area of the tank bottom plate is large, and the tank bottom plate can be comprehensively and quickly inspected, the surface of the test sample does not need to be pretreated and coated with a coupling agent, the surface requirement of the measured structure is low, the corrosion defect composite detection and positioning in a large range and full angle area are realized, and the technical problem that the ultrasonic guided wave and the magnetic flux leakage comprehensive detection of the measured material cannot be realized in the prior art is solved.The detection efficiency of the tank bottom plate is improved, and the consumption of manpower and material resources is reduced.The electromagnetic ultrasonic guided wave transducer can excite omnidirectional horizontal shear guided waves, which interact with corrosion defects to produce echoes, and the corrosion defects of the tank bottom plate in a certain range can be accurately positioned through the collection of the echo signals by the outer ring circumferential receiving coil.

[0007] Further, the first outer ring magnet, the second outer ring magnet and the inner ring magnet are coaxially arranged.

[0008] The beneficial effects of the above further technical scheme are that the material of the measured structure is magnetized, and a magnetic field signal is generated in the interior of the measured structure.

[0009] Further, the annular excitation coil is wound outside the combination of the second outer ring magnet and the inner ring magnet.

[0010] The beneficial effects of the above further technical scheme are that the second outer ring magnet and the inner ring magnet provide a bias static magnetic field in the radial direction opposite to the bottom of the tank, and excite omnidirectional horizontal shear guided waves, that is, the second outer ring magnet, the inner ring magnet and the annular excitation coil wound on the combination of the second outer ring magnet and the inner ring magnet cooperate to generate electromagnetic ultrasonic guided waves.The second outer ring magnet and the inner ring magnet provide a static bias magnetic field perpendicular to the test piece, the annular excitation coil is connected to a high-frequency excitation current and generates a radial distributed induced eddy current on the surface of the measured tank bottom plate, the induced eddy current is subjected to the Lorentz force under the action of the static bias magnetic field, and the high-frequency vibration of the plate surface particles is induced, and then omnidirectional horizontal shear guided waves are excited.

[0011] Further, the isolation layer comprises a pair of silicon steel sheets and an epoxy resin intermediate layer, the pair of silicon steel sheets are connected with the first outer ring magnet and the second outer ring magnet one by one, the epoxy resin intermediate layer is installed between the pair of silicon steel sheets, and the Hall element is located at the bottom of the epoxy resin intermediate layer.

[0012] The beneficial effect of the further technical scheme is that the isolation layer is composed of silicon steel sheets on both sides and an epoxy resin middle layer, wherein the silicon steel sheets surrounding the first outer ring magnet and the second outer ring magnet act as high magnetic permeability materials to shield the magnetic field between the two, preventing mutual signal interference and affecting the accuracy of corrosion detection.

[0013] Further, the N-pole of the first outer ring magnet is above the S-pole, the N-pole of the second outer ring magnet is below the S-pole, and the N-pole of the inner ring magnet is above the S-pole.

[0014] The beneficial effect of the further technical scheme is that large-scale storage tank bottom plate corrosion detection can be achieved without direct contact or ultrasonic coupling, and the structure of the annular permanent magnet is reasonably designed, the annular excitation coil, the annular receiving coil, and the Hall element are arranged to realize the organic integration of magnetic flux leakage detection and electromagnetic ultrasonic guided wave detection technology. The single detection range is large, which facilitates comprehensive and rapid inspection of the large-area storage tank bottom plate, and the surface of the test sample does not need to be pretreated or smeared with a coupling agent, and the surface of the test structure has low requirements, realizing corrosion defect composite detection and positioning in a large-scale full-angle area, solving the technical problem that the existing technology cannot realize ultrasonic guided wave and magnetic flux leakage comprehensive detection of the test material, improving the detection efficiency of the storage tank bottom plate, and reducing the consumption of manpower and resources. The electromagnetic ultrasonic guided wave transducer can excite omnidirectional horizontal shear guided waves, which interact with corrosion defects to produce echoes, and the echoes can be accurately positioned by the circumferential receiving coil.

[0015] Further, the top end and the bottom end of the first outer ring magnet, the second outer ring magnet, and the inner ring magnet are located on the same plane.

[0016] The beneficial effect of the further technical scheme is that the installation and maintenance of the storage tank bottom plate detection device are facilitated, and the storage and transportation of the storage tank bottom plate detection device are facilitated, so that the storage tank bottom plate detection device is compact in structure.

[0017] Further, the first outer ring magnet, the second outer ring magnet, and the inner ring magnet are all annular structures.

[0018] The beneficial effect of the further technical scheme is that the installation and maintenance of the storage tank bottom plate detection device are facilitated, and the storage and transportation of the storage tank bottom plate detection device are facilitated, so that the storage tank bottom plate detection device is compact in structure.

[0019] Further, the application also provides a storage tank bottom plate detection method based on the storage tank bottom plate detection device.

[0020] S1, the storage tank bottom plate detection device is close to the storage tank bottom plate to be detected;

[0021] S2, the annular excitation coil excites the horizontal shear guided wave propagating in the 360° direction to perform corrosion detection on the storage tank bottom plate;

[0022] S3, the annular receiving coil analyzes the reflected guided wave signal to locate the corrosion defects in the detection range;

[0023] S4, the Hall element analyzes the magnetic flux leakage signal of the storage tank bottom plate to be detected to obtain the corrosion information of the storage tank bottom plate to be detected below the storage tank bottom plate detection device.

[0024] The beneficial effects of the technical scheme of the application are that the corrosion detection of the storage tank bottom plate in a large range can be realized without direct contact and ultrasonic coupling, the structure of the annular permanent magnet is reasonably designed, the annular excitation coil, the annular receiving coil and the Hall element are arranged, the organic integration of the magnetic flux leakage detection and the electromagnetic ultrasonic guided wave detection technology is realized, the single detection range is large, the area of the storage tank bottom plate is large, and the storage tank bottom plate can be conveniently and quickly checked comprehensively, the surface of the test sample does not need to be pretreated and coated with a coupling agent, the surface requirement of the measured structure is low, the corrosion defect composite detection and positioning in a large range and full angle area are realized, the technical problem that the ultrasonic guided wave and the magnetic flux leakage comprehensive detection of the measured material cannot be realized in the prior art is solved, the detection efficiency of the storage tank bottom plate is improved, and the consumption of manpower and material resources is reduced.

[0025] Further, the step S3 comprises:

[0026] The storage tank bottom plate detection device is rotated, the reflected guided wave signal is received by the different segmented annular receiving coils, and the corrosion information of the storage tank bottom plate to be detected is comprehensively analyzed.

[0027] The beneficial effects of the above further technical scheme are that the reflected guided wave signal is received by the different segmented annular receiving coils, and the positioning accuracy of the corrosion defects of the storage tank bottom plate can be further improved.

[0028] The advantages of the additional aspects of the application will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a sectional view of the storage tank bottom plate detection device provided by the embodiment of the present application.

[0030] Figure 2 is a structural schematic diagram of the omni-directional electromagnetic ultrasonic guided wave transducer magnetic flux leakage detection sensor provided by the embodiment of the present application.

[0031] Figure 3 is a sectional view of the omni-directional electromagnetic ultrasonic guided wave transducer provided by the embodiment of the present application.

[0032] Figure 4 is a sectional view of the first outer ring magnet and the second outer ring magnet structure provided by the embodiment of the present application.

[0033] Figure 5 is a structural schematic diagram of the storage tank bottom plate detection device provided by the embodiment of the present application.

[0034] Figure 6 is a schematic flow chart of the storage tank bottom plate detection method provided by the embodiment of the present application.

[0035] Explanation of reference numerals: 1, first outer ring magnet; 2, second outer ring magnet; 3, inner ring magnet; 4, annular excitation coil; 5, isolation layer; 6, annular receiving coil; 7, Hall element; 8, silicon steel sheet; 9, epoxy resin intermediate layer. DETAILED DESCRIPTION

[0036] The principles and features of the present application are described below in conjunction with the accompanying drawings, and the examples are only used to explain the present application and are not used to limit the scope of the present application.

[0037] As shown in Figures 1 to 5 , the embodiment of the present application provides a storage tank bottom plate detection device, which comprises: a first outer ring magnet 1, a second outer ring magnet 2, an inner ring magnet 3, an annular excitation coil 4, an isolation layer 5, a plurality of annular receiving coils 6, and a Hall element 7, the second outer ring magnet 2 is sleeved on the outer side of the inner ring magnet 3, the first outer ring magnet 1 is sleeved on the outer side of the second outer ring magnet 2, the annular excitation coil 4 is wound on the outer side of the second outer ring magnet 2 and the inner ring magnet 3, a plurality of annular receiving coils 6 are wound on the first outer ring magnet 1 along the circumference of the first outer ring magnet 1, the isolation layer 5 is installed between the first outer ring magnet 1 and the second outer ring magnet 2, and the Hall element 7 is installed in the isolation layer 5.

[0038] The beneficial effects of the technical scheme of the present application are: without direct contact and ultrasonic coupling, large-range corrosion detection of the tank bottom plate can be realized, the structure of the annular permanent magnet is reasonably designed, the annular excitation coil, the annular receiving coil and the Hall element are arranged, and the organic integration of the magnetic flux leakage detection and the electromagnetic ultrasonic guided wave detection technology is realized. The single detection range is large, which is convenient for comprehensive and rapid inspection of the large-area tank bottom plate, the surface of the tested sample does not need to be pretreated and smeared with a coupling agent, the surface requirement of the measured structure is low, the corrosion defect composite detection and positioning in a large-range full-angle area are realized, and the technical problem that the existing technology cannot realize the ultrasonic guided wave and magnetic flux leakage comprehensive detection of the measured material is solved. The detection efficiency of the tank bottom plate is improved, and the consumption of manpower and material resources is reduced. The omnidirectional horizontal shear guided wave can be excited by using the electromagnetic ultrasonic guided wave transducer, and echoes are generated after the interaction with the corrosion defect. The corrosion defect of the tank bottom plate in a certain range can be accurately positioned by collecting the echo signals through the outer ring circumferential receiving coil.

[0039] The structure of the annular permanent magnet is reasonably designed, the annular excitation coil, the receiving coil (annular receiving coil) and the Hall element are arranged, and the organic integration of the magnetic flux leakage detection and the electromagnetic ultrasonic guided wave detection technology is realized. Without coupling contact with the surface of the test piece (tank bottom plate), the omnidirectional horizontal shear guided wave can be excited by using the electromagnetic ultrasonic guided wave transducer, and echoes are generated after the interaction with the corrosion defect. The corrosion defect of the tank bottom plate in a certain range can be accurately positioned by collecting the echo signals through the outer ring circumferential receiving coil (annular receiving coil). The second outer ring magnet and the inner ring magnet provide a bias static magnetic field in the radial direction opposite to the tank bottom (tank bottom plate), and excite the omnidirectional propagation of the horizontal shear guided wave. Without pretreatment and smearing of the coupling agent on the surface of the test sample (tank bottom plate), the surface requirement of the measured structure (tank bottom plate) is low, and the corrosion defect composite detection and positioning in a large-range full-angle area are realized.

[0040] Figure 1 In the figure, the spiral arrow pointing to the left represents the direction of the excited guided wave signal, and the spiral arrow pointing to the right represents the direction of the reflected guided wave signal. Figure 2 The arrow in the figure represents the transmission direction and trajectory of the signal. Figure 3 The spiral arrow in the figure represents the direction of the SH0 guided wave. Figure 5 The bidirectional arrow in the figure represents the position of the annular receiving coil.

[0041] As shown in Figures 1 to 5 Further, the first outer ring magnet 1, the second outer ring magnet 2 and the inner ring magnet 3 are coaxially arranged.

[0042] The beneficial effects of the above further technical scheme are: the material of the measured structure is magnetized, and a magnetic field signal is generated in the interior of the measured structure.

[0043] As shown in Figures 1 to 5 Further, the annular excitation coil 4 is wound outside the combination of the second outer ring magnet 2 and the inner ring magnet 3.

[0044] The beneficial effect of the above further technical solution is that the second outer ring magnet and the inner ring magnet provide a bias static magnetic field in the opposite radial direction at the bottom of the tank, exciting a horizontally shearing guided wave propagating in all directions. That is, the second outer ring magnet, the inner ring magnet, and the annular excitation coil wound on the combination of the second outer ring magnet and the inner ring magnet cooperate to generate an electromagnetic ultrasonic guided wave. The second outer ring magnet and the inner ring magnet provide a static bias magnetic field perpendicular to the test piece, and the annular excitation coil is connected to a high-frequency excitation current and generates a radial distribution of induced eddy current on the surface of the bottom plate of the measured tank. Under the action of the static bias magnetic field, the induced eddy current is subjected to the Lorentz force to induce high-frequency vibration of the plate surface particles, and further excite a horizontally shearing guided wave propagating in all directions.

[0045] As shown in Figures 1 to 5 Further, the isolation layer 5 includes a pair of silicon steel sheets 8 and an epoxy resin intermediate layer 9, and the pair of silicon steel sheets 8 are connected to the first outer ring magnet 1 and the second outer ring magnet 2 one by one. The epoxy resin intermediate layer 9 is installed between the pair of silicon steel sheets 8, and the Hall element 7 is located at the bottom of the epoxy resin intermediate layer 9.

[0046] The beneficial effect of the above further technical solution is that the isolation layer is provided between the first outer ring magnet and the second outer ring magnet, and the lower part is a uniform magnetic field area. A magnetic field measurement sensor such as a Hall element is arranged in the middle of the uniform magnetic field area, which is used to detect whether there is a magnetic field signal outside the test structure, and can realize the magnetic flux leakage detection of corrosion defects. The isolation layer is composed of two silicon steel sheets and an epoxy resin intermediate layer. The silicon steel sheets surrounding the first outer ring magnet and the second outer ring magnet act as high magnetic permeability materials to shield the magnetic field between the two, prevent mutual signal interference, and affect the accuracy of corrosion detection.

[0047] As shown in Figures 1 to 5 Further, the N-pole of the first outer ring magnet 1 is located above the S-pole, the N-pole of the second outer ring magnet 2 is located below the S-pole, and the N-pole of the inner ring magnet 3 is located above the S-pole.

[0048] The beneficial effect of the further technical scheme is that the corrosion detection of the large range of the storage tank bottom plate can be realized without direct contact and ultrasonic coupling, the structure of the annular permanent magnet is reasonably designed, the annular excitation coil, the annular receiving coil and the Hall element are arranged, the organic fusion of the magnetic flux leakage detection and the electromagnetic ultrasonic guided wave detection technology is realized, the single detection range is large, the area of the storage tank bottom plate is large, and the comprehensive and rapid inspection is facilitated, the surface of the tested sample does not need to be pretreated and smeared with a coupling agent, the surface requirement of the measured structure is low, the corrosion defect composite detection and positioning in the large range and full angle area are realized, the technical problem that the existing technology cannot realize the ultrasonic guided wave and magnetic flux leakage comprehensive detection of the measured material is solved, the detection efficiency of the storage tank bottom plate is improved, and the consumption of manpower and material resources is reduced. The electromagnetic ultrasonic guided wave transducer can excite omnidirectional horizontal shear guided waves, which interact with the corrosion defects to generate echoes, and the corrosion defects of the storage tank bottom plate in a certain range can be accurately positioned through the collection of the echo signals by the outer ring circumferential receiving coil.

[0049] As shown in Figures 1 to 5 , further, the top end and the bottom end of the first outer ring magnet 1, the second outer ring magnet 2 and the inner ring magnet 3 are located on the same plane.

[0050] The beneficial effect of the further technical scheme is that the installation and maintenance of the storage tank bottom plate detection device are facilitated, the storage and transportation of the storage tank bottom plate detection device are facilitated, and the structure of the storage tank bottom plate detection device is compact.

[0051] As shown in Figure 6 , further, the first outer ring magnet 1, the second outer ring magnet 2 and the inner ring magnet 3 are annular structures.

[0052] The beneficial effect of the further technical scheme is that the installation and maintenance of the storage tank bottom plate detection device are facilitated, the storage and transportation of the storage tank bottom plate detection device are facilitated, and the structure of the storage tank bottom plate detection device is compact.

[0053] 1. The detection sensor device (storage tank bottom plate detection device) and the metal structure (storage tank bottom plate) surface are implemented at a certain distance, without direct contact and ultrasonic coupling, to realize large range corrosion detection of the storage tank bottom plate, the structure distribution of the permanent magnet (first outer ring magnet, second outer ring magnet and inner ring magnet) is reasonably designed, the fusion of the electromagnetic guided wave detection and the magnetic flux leakage detection method is formed, and the technical problem that the existing technology cannot realize the ultrasonic guided wave and magnetic flux leakage comprehensive detection of the measured material (storage tank bottom plate) is solved.

[0054] 2. By rationally designing the structure of the annular permanent magnet (first outer ring magnet, second outer ring magnet, and inner ring magnet), and arranging the annular excitation coil, receiving coil (circular receiving coil), and Hall element, the organic integration of magnetic flux leakage detection and electromagnetic ultrasonic guided wave detection technologies can be achieved. Without coupling contact with the surface of the test piece (tank bottom plate), the electromagnetic ultrasonic guided wave transducer can excite omnidirectional horizontal shear guided waves. These waves interact with corrosion defects to generate echoes. By acquiring the echo signals through the outer circumferential receiving coil (circular receiving coil), corrosion defects on the tank bottom plate within a certain range can be accurately located.

[0055] Magnetic leakage signals are low-frequency signals (below 5kHz), while electromagnetic ultrasonic guided wave detection uses a frequency range of 5–300kHz. Although their signal characteristics differ, both require a magnetizer to magnetize the component (tank bottom plate) or the synergistic effect of dynamic and static magnetic fields for signal excitation and reception. Therefore, this invention, through the rational arrangement of toroidal permanent magnets and different frequency domain signal excitation and reception methods, organically integrates electromagnetic ultrasonic guided wave technology and magnetic leakage detection technology, leveraging their respective characteristics to achieve complementary advantages and significantly improve detection efficiency. During the detection process, the characteristics of electromagnetic ultrasonic guided wave—point-to-point excitation and long-distance detection—are first utilized to rapidly detect large areas of the tank bottom plate, initially locating severely corroded areas. Then, a sensor (Hall element) is moved to this area, and the magnetic leakage method is used to accurately detect the location and size of defects. Furthermore, electromagnetic ultrasonic guided wave technology can perform long-distance coverage detection in areas difficult for ordinary sensors to reach.

[0056] A tank bottom plate detection device is a non-contact composite detection device for tank bottom plates, comprising a ring permanent magnet (a first outer ring magnet, a second outer ring magnet, and an inner ring magnet), a ring excitation coil 4, an isolation layer 5, N circumferentially distributed ring receiving coils 6, and a Hall element 7. The ring permanent magnet includes a first outer ring magnet 1, a second outer ring magnet 2, and an inner ring magnet 3 coaxially connected in sequence; it is used to magnetize the material of the structure under test (tank bottom plate) and generate a magnetic field signal inside the structure under test (tank bottom plate).

[0057] A ring-shaped excitation coil 4 is wound around the combination of the second outer ring magnet 2 and the inner ring magnet 3.

[0058] Among them, the second outer ring magnet 2, the inner ring magnet 3, and the annular excitation coil 4 wound on the combination of the second outer ring magnet and the inner ring magnet work together to generate electromagnetic ultrasonic guided waves.

[0059] Specifically, the second outer ring magnet 2 and the inner ring magnet 3 provide a static bias magnetic field perpendicular to the test piece (tank bottom plate). The ring excitation coil is connected to a high-frequency excitation current and generates radially distributed induced eddy currents on the upper surface of the tank bottom plate. Under the action of the static bias magnetic field, the induced eddy currents are subjected to Lorentz force, which induces high-frequency vibration of the particles on the plate (tank bottom plate) surface, thereby exciting omnidirectional propagating horizontal shear waves.

[0060] The main factor affecting the coverage of the horizontal shear waveguide is the circumferential spacing of the annular excitation coils 4. If the circumferential spacing of the annular excitation coils 4 is very small, the Lorentz force generated by the electromagnetic ultrasonic waveguide exciter can be guaranteed to be uniform, thereby emitting a horizontal shear wave that covers the entire 360° area. The smaller the circumferential spacing of the annular excitation coils 4, the larger the coverage of the horizontal shear waveguide.

[0061] Furthermore, the first outer ring magnet 1 is wound with N segments of annular receiving coil 6 circumferentially. By analyzing the propagation time of the echo signal and the direction of the receiving coil, corrosion defects on the bottom plate of the storage tank can be located. If the annular receiving coil 6 has enough segments, the location of corrosion defects will be more accurate.

[0062] Specifically, an isolation layer 5 is provided between the first outer ring magnet 1 and the second outer ring magnet 2, and the lower part is a uniform magnetic field region. A magnetic field measurement sensor, such as a Hall element 7, is arranged in the middle of the uniform magnetic field region to detect whether there is a magnetic field signal outside the structure under test, which can realize the leakage magnetic field detection of corrosion defects.

[0063] Furthermore, the isolation layer 5 consists of silicon steel sheets 8 on both sides and an epoxy resin intermediate layer 9. The silicon steel sheets surrounding the first outer ring magnet and the second outer ring magnet are high permeability materials that can shield the magnetic field between them, prevent mutual signal interference, and avoid affecting the accuracy of corrosion detection.

[0064] Furthermore, the tank bottom plate detection device provided in this embodiment of the invention can be a non-contact composite detection device for tank bottom plates. Its principle for detecting corrosion of tank bottom plates is as follows:

[0065] Magnetic flux leakage detection principle: When a defective ferromagnetic workpiece (such as the bottom plate of a storage tank) is subjected to a magnetic field, the magnetic flux is distorted at the defect due to the difference in magnetic permeability between the ferromagnetic material and the defect. A portion of the magnetic flux escapes from the surface of the workpiece (bottom plate of the storage tank), passes through the air, and returns to the S pole. This part is called magnetic flux leakage. The strength of the magnetic flux leakage field is proportional to the size and depth of the defect. The magnitude of this part of the magnetic flux is detected by a Hall element, and the size and depth of the defect can be determined by calculation.

[0066] Electromagnetic guided wave detection principle: A ring excitation coil is arranged in a static bias magnetic field with a spatial periodic distribution. The straight part of the ring excitation coil is located in the periodic magnetic field. The eddy current induced in the test piece (tank bottom plate) is parallel to the surface of the test piece (tank bottom plate). Under the action of Lorentz force, the direction of particle vibration is perpendicular to the direction of eddy current and parallel to the surface of the test piece (tank bottom plate). The vibration propagates in the horizontal direction, exciting a horizontal shear guided wave.

[0067] Signal processing: When using electromagnetic ultrasonic guided waves to detect corrosion defects on the bottom plate of a storage tank, the received reflected signals need to be analyzed and processed. A circumferentially segmented ring-shaped receiving coil can detect corrosion defects on the bottom plate (storage tank bottom plate) from all 360° around the device (storage tank bottom plate detection device). The orientation of the segmented coil (ring-shaped receiving coil) receiving the reflected signal represents the location of the corrosion defect. The product of half the time from excitation to signal reception and the horizontal shear wave group velocity represents the distance between the corrosion defect and the receiving coil (ring-shaped receiving coil), as shown in the equation: Where T is the time interval from the excitation of the guided wave to the receipt of the signal, and C... g Let L be the group velocity of the SH0 guided wave, and L be the distance between the corrosion defect and the receiving coil (ring receiving coil).

[0068] like ​ As shown, in addition, the present invention also provides a method for detecting the bottom plate of a storage tank, based on the storage tank bottom plate detection device described in any one of the above claims. The method for detecting the bottom plate of a storage tank includes:

[0069] S1. The tank bottom plate detection device is placed near the bottom plate of the tank to be inspected;

[0070] S2. A ring excitation coil excites a horizontal shear wave propagating in a 360° direction to detect corrosion on the bottom plate of the storage tank.

[0071] S3. The loop receiving coil analyzes the reflected guided wave signal to locate corrosion defects within the detection range;

[0072] S4. The Hall element analyzes the magnetic leakage signal of the bottom plate of the tank to be tested, and obtains the corrosion information of the bottom plate of the tank to be tested below the tank bottom plate detection device.

[0073] The beneficial effects of adopting the technical solution of this invention are as follows: It enables large-scale corrosion detection of tank bottom plates without direct contact or ultrasonic coupling. The rationally designed structure of the annular permanent magnet, along with the arrangement of annular excitation coils, annular receiving coils, and Hall elements, organically integrates magnetic flux leakage detection and electromagnetic ultrasonic guided wave detection technologies. It offers a large single-detection range, facilitating comprehensive and rapid inspection of large tank bottom plates. It eliminates the need for pretreatment and coupling agent application to the test sample surface, reducing surface requirements on the tested structure. It achieves composite detection and localization of corrosion defects over a wide, all-angle area, solving the technical problem of incomplete detection caused by the inability of existing technologies to perform comprehensive ultrasonic guided wave and magnetic flux leakage detection on the tested material. It improves the detection efficiency of tank bottom plates and reduces manpower and material consumption. The electromagnetic ultrasonic guided wave transducer can excite omnidirectional horizontal shear guided waves, which, after interacting with corrosion defects, generate echoes. By acquiring the echo signals through the outer circumferential receiving coil, corrosion defects on the tank bottom plate within a certain range can be accurately located.

[0074] Further, step S3 includes:

[0075] The rotating tank bottom plate detection device uses ring receiving coils of different segments to receive the reflected guided wave signals and comprehensively analyzes the corrosion information of the tank bottom plate to be detected.

[0076] The beneficial effect of adopting the above-mentioned further technical solution is that by using circumferential receiving coils of different segments to receive the reflected guided wave signals, the positioning accuracy of corrosion defects in the tank bottom plate can be further improved.

[0077] This invention provides a method for detecting the bottom plate of a storage tank, which can be described as a method for operating a non-contact composite detection device for the bottom plate of a storage tank, including:

[0078] Step 1: Place the composite detection device (tank bottom plate detection device) close to the tank bottom plate, and use a ring excitation coil to excite horizontal shear waves propagating in a 360° direction to detect corrosion on the tank bottom plate;

[0079] Step 2: Analyze the reflected guided wave signal to locate corrosion defects within the detection range;

[0080] Step 3: Analyze the leakage magnetic signal of the tank bottom plate using Hall elements to obtain corrosion information of the tank bottom plate below the composite detection device (tank bottom plate detection device);

[0081] Step 4: The rotating composite detection device (tank bottom plate detection device) uses circumferential receiving coils (ring receiving coils) of different segments to receive the reflected guided wave signals and comprehensively analyze the corrosion information of the tank bottom plate.

[0082] By using circumferential receiving coils (ring receiving coils) of different segments to receive the reflected guided wave signals, the positioning accuracy of corrosion defects in the tank bottom plate can be further improved.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tank bottom plate detection device, characterized in that, include: The system comprises a first outer ring magnet, a second outer ring magnet, an inner ring magnet, a ring excitation coil, an isolation layer, multiple ring receiving coils, and a Hall element. The second outer ring magnet is sleeved outside the inner ring magnet, and the first outer ring magnet is sleeved outside the second outer ring magnet. The ring excitation coil is wound around the outer sides of both the second outer ring magnet and the inner ring magnet. Multiple ring receiving coils are wound around the first outer ring magnet circumferentially. The isolation layer is installed between the first outer ring magnet and the second outer ring magnet, and the Hall element is installed within the isolation layer. The second outer ring magnet and the inner ring magnet are coaxially arranged; the annular excitation coil is wound around the outside of the assembly formed by the second outer ring magnet and the inner ring magnet; the isolation layer includes: a pair of silicon steel sheets and an epoxy resin intermediate layer, the pair of silicon steel sheets are connected to the first outer ring magnet and the second outer ring magnet respectively, the epoxy resin intermediate layer is installed between the pair of silicon steel sheets, and the Hall element is located at the bottom of the epoxy resin intermediate layer; the N pole of the first outer ring magnet is located above the S pole, the N pole of the second outer ring magnet is located below the S pole, and the N pole of the inner ring magnet is located above the S pole.

2. The tank bottom plate detection device according to claim 1, characterized in that, The top and bottom ends of the first outer ring magnet, the second outer ring magnet, and the inner ring magnet are located on the same plane.

3. The tank bottom plate detection device according to claim 1, characterized in that, The first outer ring magnet, the second outer ring magnet, and the inner ring magnet are all ring structures.

4. A method for detecting the bottom plate of a storage tank, characterized in that, Based on the tank bottom plate detection device according to any one of claims 1 to 3, a tank bottom plate detection method includes: S1. The tank bottom plate detection device is placed near the bottom plate of the tank to be inspected; S2. A ring excitation coil excites a horizontal shear wave propagating in a 360° direction to detect corrosion on the bottom plate of the storage tank. S3. The loop receiving coil analyzes the reflected guided wave signal to locate corrosion defects within the detection range; S4. The Hall element analyzes the magnetic leakage signal of the bottom plate of the tank to be tested, and obtains the corrosion information of the bottom plate of the tank to be tested below the tank bottom plate detection device. Step S3 includes: The rotating tank bottom plate detection device uses ring receiving coils of different segments to receive the reflected guided wave signals and comprehensively analyzes the corrosion information of the tank bottom plate to be detected.

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