Pipeline internal penetrating type rotating eddy current array detection device and method

Abstract

The invention discloses a pipeline internal penetrating type rotating eddy current array detection device and method. The pipeline internal penetrating type rotating eddy current array detection device comprises a mounting part, an alternating current power supply assembly, a detection coil and two excitation coils, the two excitation coils are wound on the mounting part, the winding axes of the two excitation coils are overlapped, and the two excitation coils are sequentially arranged along the winding axes; the alternating current power supply assembly is electrically connected with the two exciting coils and enables the current flow directions of the two exciting coils to be opposite; the detection coil is arranged on the installation part and located between the two excitation coils. In the scheme, the direction of the radial polarization magnetic field is perpendicular to the surface of the pipe wall all the time, and the optimal excitation condition of the eddy current skin effect is met; and the rotating eddy current field generated by induction has omnidirectional sensitivity, and no matter which angle is formed between the defect trend and the moving direction of the probe, a remarkable eddy current disturbance signal can be generated, so that the universal detection of circumferential, axial and oblique defects is realized, the missing detection is avoided, and the defect detection accuracy is improved.

Description

Technical Field

[0001] This invention relates to the field of eddy current flaw detection equipment technology, specifically to a pipe-penetrating rotating eddy current array detection device and method. Background Technology

[0002] Steel pipes are widely used in chemical, petroleum, construction and nuclear energy fields. Given the wide application of steel pipes and the huge production and demand, the production quality and safety of steel pipes have become of paramount importance. Therefore, it is necessary to use flaw detection equipment to detect whether steel pipes have defects.

[0003] Publication number CN201716296U discloses a steel pipe eddy current flaw detection device. Its principle is to use an excitation coil to generate eddy current in the conductive component to be tested, and use a detection coil to measure the change in eddy current to obtain relevant information about the component defects. When a defect is found in the steel pipe, the marking device receives an instruction from the computer control system to mark the steel pipe.

[0004] However, existing excitation coils are usually directly wound in a ring around the outer periphery of the magnetic yoke. The ring-shaped eddy current field induced by it does not have omnidirectional sensitivity. When the defect direction is perpendicular to the probe movement direction, it cannot generate obvious eddy current disturbance signal, resulting in inaccurate detection. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a pipe-penetrating rotating eddy current array detection device and method. This invention solves the technical problem in the prior art where the excitation coil is usually directly wound in a ring around the outer periphery of the magnetic yoke, and the annular eddy current field induced by it does not have omnidirectional sensitivity. When the defect direction is perpendicular to the probe movement direction, it cannot generate obvious eddy current disturbance signals, resulting in inaccurate detection.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a pipe-penetrating rotating eddy current array detection device, comprising: Installation Department; Two excitation coils are wound around the mounting portion, and the winding axes of the two excitation coils coincide and are arranged sequentially along the winding axes; An AC power supply assembly is electrically connected to the two excitation coils, and the current flows in opposite directions in the two excitation coils; and A detection coil is disposed in the mounting part and located between the two excitation coils. The distance between the detection coil and the winding axis is greater than the distance between the excitation coil and the winding axis. The detection coil is used to generate an induced current under the combined action of the electromagnetic field generated by the excitation coil and the eddy current induced magnetic field generated by the ferromagnetic component to be detected. The induced current generated by the detection coil changes synchronously with the eddy current induced magnetic field generated by the ferromagnetic component to be detected.

[0007] In some embodiments, the pipe-penetrating rotating eddy current array detection device further includes an electrical connector that connects two of the excitation coils; The two excitation coils are wound in opposite directions on the mounting portion. The AC power supply assembly has two terminals, which are electrically connected to the two excitation coils respectively and can form an electrical circuit.

[0008] In some embodiments, the electrical connector includes a connecting wire that is connected to and integrally disposed with the two excitation coils.

[0009] In some embodiments, the AC power supply assembly includes a power supply and a signal generator, the power supply being connected to the power connection terminal of the signal generator, and the signal generator having two signal output terminals, which constitute the wiring terminal.

[0010] In some embodiments, a plurality of detection coils are provided, and the plurality of detection coils are located outside the excitation coil and arranged sequentially along the circumference of the excitation coil.

[0011] In some embodiments, the two excitation coils are spaced apart along the winding axis and have a gap between them; The orthographic projection of the detection coil on the mounting portion falls within the gap.

[0012] In some embodiments, the two excitation coils are arranged symmetrically along the center of the gap.

[0013] In some embodiments, the mounting portion includes a magnetic yoke and a connecting structure. The sidewall of the magnetic yoke is provided with a mounting groove along the circumferential direction. The connecting structure is connected to the magnetic yoke and has a connecting end located outside the mounting groove. The orthographic projection of the connecting end on the magnetic yoke falls within the mounting groove. The two excitation coils are located on the bottom wall of the mounting groove, and the detection coil is located at the connection end.

[0014] In some embodiments, the detection coil is connected to an amplification and detection circuit unit, and the amplification and detection circuit unit is electrically connected to an industrial control computer.

[0015] Secondly, this solution also provides a method for detecting pipe-penetrating rotating eddy current arrays, applied to the pipe-penetrating rotating eddy current array detection device described in any of the above claims, comprising: The current supplied to the two excitation coils is gradually increased from zero, and the induced current signal of the detection coil is acquired until the induced current signal first increases and then decreases with the current supplied to the two excitation coils. Obtain the current values ​​sent to the two excitation coils at the turning point of the induced current signal to obtain the preset current value; When the pipe-through rotating eddy current array detection device detects the ferromagnetic component to be tested, the current value supplied to the two excitation coils is controlled to be the preset current value.

[0016] Compared with the prior art, the pipe-penetrating rotating eddy current array detection device provided by the present invention delivers currents to the two excitation coils in opposite directions, causing the two excitation coils to form axial magnetic field components with opposite directions and radial components with the same phase. Specifically, in the central region of the mounting part, the axial components of the magnetic fields formed by the two excitation coils cancel each other out due to their opposite phases, while the radial components are superimposed and enhanced due to their same phases, ultimately forming a radially polarized main magnetic field in the central region of the probe. This magnetic field is always perpendicular to the pipe wall and can excite a rotating eddy current field distributed along the circumference of the pipe on the inner surface of the pipe.

[0017] Radial polarized magnetic fields have two key advantages: First, the direction of the main magnetic field is always perpendicular to the pipe wall surface, which meets the optimal excitation conditions for the eddy current skin effect. Second, the rotating eddy current field it induces has omnidirectional sensitivity; regardless of the angle between the defect orientation and the probe movement direction, it can generate significant eddy current disturbance signals, thereby achieving universal detection of circumferential, axial, and oblique defects, avoiding missed detections, and improving the accuracy of defect detection. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the pipe-penetrating rotating eddy current array detection device provided in an embodiment of the present invention; Figure 2 yes Figure 1 Another schematic diagram of the rotating eddy array detection device inside the pipeline.

[0019] Explanation of reference numerals in the attached figures: 1. Mounting section; 11. Magnetic yoke; 11a. Mounting slot; 2. Excitation coil; 2a. Gap; 21. Winding axis; 3. Detection coil; 4. Ferromagnetic component to be tested. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0021] To address the technical problem that existing technologies typically involve excitation coils directly wound in a ring around the outer periphery of a magnetic yoke, resulting in an induced ring-shaped eddy current field that lacks omnidirectional sensitivity and fails to generate significant eddy current disturbance signals when the defect path is perpendicular to the probe's movement direction, leading to inaccurate detection, this invention provides a pipe-penetrating rotating eddy current array detection device. This device enables universal detection of circumferential, axial, and oblique defects in ferromagnetic pipes, avoiding missed detections and improving defect detection accuracy.

[0022] Please see Figure 1 , Figure 1 This is a schematic diagram of a pipe-inserting rotating eddy current array detection device according to an embodiment of the present invention. The pipe-inserting rotating eddy current array detection device includes a mounting part 1, an AC power supply assembly, a detection coil 3, and two excitation coils 2. Both excitation coils 2 are wound around the mounting part 1, and the winding axes 21 of the two excitation coils 2 coincide and are arranged sequentially along the winding axes 21. The AC power supply assembly (not shown) is electrically connected to the two excitation coils 2, and the current flows in opposite directions in the two excitation coils 2. The detection coil 3 is located in the mounting part 1, between the two excitation coils 2, and its distance from the winding axis 21 is greater than the distance between the excitation coil 2 and the winding axis 21. It is used to generate an induced current under the combined action of the electromagnetic field generated by the excitation coil 2 and the eddy current induced magnetic field generated by the ferromagnetic component 4 to be detected, and the generated induced current changes synchronously with the eddy current induced magnetic field generated by the ferromagnetic component 4 to be detected. Specifically, the detection coil 3 is located outside the excitation coil 2.

[0023] In the pipe-penetrating rotating eddy current array detection device provided by the present invention, the current supplied to the two excitation coils 2 is in opposite directions, causing the two excitation coils 2 to form axial magnetic field components with opposite directions and radial components with the same phase. Specifically, in the central region of the mounting part 1, the axial components of the magnetic fields formed by the two excitation coils 2 cancel each other out due to their opposite phases, while the radial components are superimposed and enhanced due to their same phases, ultimately forming a radially polarized main magnetic field in the central region of the probe. The direction of this magnetic field is always perpendicular to the pipe wall, which can excite a rotating eddy current field distributed along the circumference of the pipe on the inner surface of the pipe.

[0024] Radial polarized magnetic fields have two key advantages: First, the direction of the main magnetic field is always perpendicular to the pipe wall surface, meeting the optimal excitation conditions for the eddy current skin effect. Second, the rotating eddy current field it induces has omnidirectional sensitivity; regardless of the angle between the defect orientation and the probe movement direction, it can generate significant eddy current disturbance signals, thereby achieving universal detection of circumferential, axial, and oblique defects, avoiding missed detections, and improving defect detection accuracy. It should be noted that the winding axis 21 is the central axis when the excitation coil 2 is wound.

[0025] Furthermore, it should be noted that in one embodiment, the two excitation coils 2 are set independently, and the AC power supply components are set as two independent power supplies to supply power to the two excitation coils 2 respectively, and the current flowing to the two excitation coils 2 is controlled to flow in opposite directions. In another embodiment, the current flowing to the two excitation coils 2 can be reversed by using a single AC power supply component and controlling the wiring direction.

[0026] In another embodiment, the pipe-penetrating rotating eddy current array detection device further includes an electrical connector that connects two excitation coils 2. The two excitation coils 2 are wound in opposite directions on the mounting part 1. The AC power supply assembly has two terminals that are electrically connected to the two excitation coils 2 respectively and can form an electrical circuit.

[0027] In this embodiment, the two excitation coils 2 are connected as a whole by electrical connectors, and the two terminals of the AC power supply assembly are respectively connected to the two excitation coils 2. Thus, when the circuit is turned on, the current in the two excitation coils 2 can flow in opposite directions, and the structure is simple and reliable.

[0028] It should be noted that, in one embodiment, the electrical connector is set as a portion of the conductive area on the mounting part 1. In another embodiment, the electrical connector is set as an electrical connecting piece, through which two excitation coils are connected (2 turns).

[0029] In another embodiment, the electrical connector includes connecting wires that are connected to the two excitation coils 2 and are integrally formed with the two excitation coils 2.

[0030] In this embodiment, the connecting wire is integrally set with the two excitation coils 2, so that two excitation coils 2 with opposite winding directions can be formed by winding a single wire on the mounting part 1, and the connecting wire is located between the two excitation coils 2, thereby improving production convenience.

[0031] In one embodiment, the AC power supply assembly includes a power supply and a signal generator. The power supply is connected to the power connection terminal of the signal generator, and the signal generator has two signal output terminals that constitute wiring terminals.

[0032] In this embodiment, the signal generator is powered by a power supply, and the signal generator outputs a sinusoidal current signal, which is applied to two excitation coils 2. The detection coil 3 receives the electromagnetic field generated by the excitation coil 2 and induces eddy currents in the ferromagnetic component 4 to be tested. The electromagnetic field generated by the eddy current field below the detection coil 3 and the electromagnetic field generated by the excitation coil 2 together determine the induced voltage of the detection coil 3. The defect is detected by obtaining the change of the eddy current induced magnetic field through the detection coil 3.

[0033] It should be noted that the specific structure and working principle of the signal generator are existing technologies and will not be elaborated here.

[0034] In one embodiment, please refer to Figure 2 Multiple detection coils 3 are provided, and the multiple detection coils 3 are located outside the excitation coil 2 and are arranged sequentially along the circumference of the excitation coil 2.

[0035] In this embodiment, multiple detection coils 3 are arranged circumferentially along the mounting part 1 to further improve detection accuracy.

[0036] In one embodiment, two excitation coils 2 are spaced apart along the winding axis 21 and form a gap 2a; the orthographic projection of the detection coil 3 on the mounting part 1 falls into the gap 2a.

[0037] In this embodiment, the detection coil 3 is positioned directly opposite the gap 2a between the two excitation coils 2, so that the radial component of the magnetic field formed by the two excitation coils 2 can effectively point to the detection coil 3, thereby improving the detection accuracy.

[0038] In one embodiment, the two excitation coils 2 are arranged symmetrically along the center of the gap 2a.

[0039] In this embodiment, the two excitation coils 2 are symmetrically arranged, and the number of turns and size of the two excitation coils 2 are controlled to be the same, so that the axial components of the magnetic field formed by the two excitation coils 2 can stably cancel each other out.

[0040] It should be noted that the mounting part 1 can be configured as a mounting base, mounting arm or other forms.

[0041] In one embodiment, the mounting part 1 includes a magnetic yoke 11 and a connecting structure (not shown). The side wall of the magnetic yoke 11 is provided with a mounting groove 11a along the circumferential direction. The connecting structure is connected to the magnetic yoke 11 and has a connecting end located outside the mounting groove 11a. The orthographic projection of the connecting end on the magnetic yoke 11 falls within the mounting groove 11a. Two excitation coils 2 are provided on the bottom wall of the mounting groove 11a, and a detection coil 3 is provided at the connecting end.

[0042] In this embodiment, the mounting part 1 is configured in the form of a magnetic yoke 11, and two excitation coils 2 are wound in the mounting groove 11a of the magnetic yoke 11 to increase the strength of the magnetic field formed by the excitation coils 2. It should be noted that the connecting structure can be configured as a connecting arm, a connecting frame, or a connecting seat. In one embodiment, the connecting structure is configured as an inner frame, a connecting arm, and an outer frame. The inner frame is wound around the bottom wall of the mounting groove 11a and located within the gap 2a. The connecting arm extends radially along the magnetic yoke 11 and extends out of the mounting groove 11a, connecting the inner frame and the outer frame. The outer frame forms the connecting end.

[0043] It should be noted that in this scheme, the distance between the inner wall of the magnetic yoke 11 and the ferromagnetic part 4 to be tested is fixed at 0-3mm.

[0044] In one embodiment, the detection coil 3 is connected to an amplification and detection circuit unit, which is electrically connected to an industrial control computer.

[0045] In this embodiment, the excitation coil 2 and the detection coil 3 move horizontally along the ferromagnetic component 4 to be detected. When passing through the defect area, the detection coil 3 acquires the change in the eddy current induced magnetic field. The eddy current signal is demodulated by the amplification and detection circuit unit and displayed on the industrial control computer, thereby locating the defect area. It should be noted that the specific structure and working principle of the amplification and detection circuit unit and the industrial control computer are existing technologies and will not be described in detail here.

[0046] Furthermore, the present invention also provides a method for detecting pipe-penetrating rotating eddy current arrays, applied to the pipe-penetrating rotating eddy current array detection device described above, comprising: The current supplied to the two excitation coils 2 is gradually increased from zero, and the induced current signal of the detection coil 3 is acquired until the induced current signal first increases and then decreases with the current supplied to the two excitation coils 2. Obtain the current values ​​sent to the two excitation coils 2 at the turning point of the induced current signal to get the preset current value; When the pipe-inserted rotary induction current array detection device detects the ferromagnetic component 4 to be detected, the current value supplied to the two excitation coils 2 is controlled to be the preset current value.

[0047] In this embodiment, the output current of the signal generator is linearly increased starting from 0A, while the eddy current signal displayed on the industrial control computer is recorded simultaneously. When the intensity of the eddy current signal first increases and then decreases with the increase of the adjustable current source current, the excitation intensity corresponding to the inflection point of the voltage amplitude is the optimal eddy current excitation intensity. At this point, the eddy current detection accuracy and detection depth are the highest. It should be understood that the ferromagnetic component 4 to be detected is the steel pipe to be detected.

[0048] To better understand this invention, the following is combined with... Figure 1 and Figure 2 The technical solution of the present invention will be described in detail below: The detection process of the pipe-penetrating rotating eddy array detection device in this solution is as follows: S1: A sine wave is output by the signal generator and loaded onto two excitation coils 2. The detection coil 3 receives the electromagnetic field generated by the excitation coil 2 and induces the eddy current in the ferromagnetic part 4 to be detected. The electromagnetic field generated by the eddy current field below the detection coil 3 and the electromagnetic field generated by the excitation coil 2 together determine the induced voltage of the detection coil 3. S2: Move the excitation coil 2 and the detection coil 3 horizontally along the ferromagnetic part 4 to be tested. When passing through the defect area, the detection coil 3 obtains the change of the eddy current induced magnetic field. The eddy current signal is demodulated by the amplification and detection circuit unit and displayed on the industrial control computer, thereby finding the defect area. S3: Starting from 0A, linearly increase the output current of the signal generator and synchronously record the induced current signal displayed on the industrial control computer. When the intensity of the induced current signal first increases and then decreases with the increase of the adjustable current source current, the excitation intensity corresponding to the inflection point of the voltage amplitude is the optimal eddy current excitation intensity. At this time, the eddy current detection accuracy and detection depth are the highest.

[0049] S4: Move the excitation coil 2 and the detection coil 3 along the horizontal straight line of the ferromagnetic part 4 to be tested, and detect the ferromagnetic part 4 with the best eddy current excitation intensity. Obtain the change of the eddy current induced magnetic field through the detection coil 3 to detect the defect.

[0050] The working principle of this invention is as follows: Eddy current nondestructive testing technology achieves nondestructive detection of defects in conductive materials through the principle of electromagnetic induction. When the detection probe sweeps across a defect-free area of ​​the pipe wall, the detection system maintains a stable electromagnetic response; however, when a defect exists, the abrupt change in the conductivity of the pipe wall leads to distortion of the eddy current field. This distortion is precisely captured by the impedance phase change of the detection coil 3, thereby achieving quantitative detection of the defect.

[0051] This scheme employs a dual-coil differential excitation mode: the AC signal output from the signal generator is input to the spatially symmetrically distributed excitation coils 2, which, guided by a magnetic core, form axial magnetic field components with opposite directions. In the central region of the probe, the axial components of the two magnetic fields cancel each other out due to their opposite phases, while the radial components are superimposed and enhanced due to their identical phases, ultimately forming a radially polarized main magnetic field in the central region of the probe. This magnetic field is always perpendicular to the pipe wall, and can excite a rotating eddy current field distributed circumferentially along the inner surface of the pipe. This specially designed radially polarized magnetic field has two key advantages: first, its direction is always perpendicular to the pipe wall surface, meeting the optimal excitation conditions for the eddy current skin effect; second, the rotating eddy current field it induces has omnidirectional sensitivity, generating significant eddy current disturbance signals regardless of the angle between the defect orientation and the probe movement direction, thus achieving universal detection of circumferential, axial, and oblique defects.

[0052] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A pipe-penetrating rotating eddy current array detection device, characterized in that, include: Installation Department; Two excitation coils are wound around the mounting portion, and the winding axes of the two excitation coils coincide and are arranged sequentially along the winding axes; An AC power supply assembly is electrically connected to the two excitation coils, and the current flows in opposite directions in the two excitation coils; and A detection coil is disposed in the mounting part and located between the two excitation coils. The distance between the detection coil and the winding axis is greater than the distance between the excitation coil and the winding axis. The detection coil is used to generate an induced current under the combined action of the electromagnetic field generated by the excitation coil and the eddy current induced magnetic field generated by the ferromagnetic component to be detected. The induced current generated by the detection coil changes synchronously with the eddy current induced magnetic field generated by the ferromagnetic component to be detected.

2. The pipe-penetrating rotating eddy current array detection device according to claim 1, characterized in that, The pipe-penetrating rotating eddy current array detection device also includes an electrical connector, which connects the two excitation coils. The two excitation coils are wound in opposite directions on the mounting portion. The AC power supply assembly has two terminals, which are electrically connected to the two excitation coils respectively and can form an electrical circuit.

3. The pipe-penetrating rotating eddy current array detection device according to claim 2, characterized in that, The electrical connector includes a connecting wire that is connected to the two excitation coils and is integrally formed with the two excitation coils.

4. The pipe-penetrating rotating eddy current array detection device according to claim 2, characterized in that, The AC power supply assembly includes a power supply and a signal generator. The power supply is connected to the power connection terminal of the signal generator. The signal generator has two signal output terminals, which constitute the wiring terminal.

5. The pipe-penetrating rotating eddy current array detection device according to claim 1, characterized in that, The detection coil is provided in multiple ways, and the multiple detection coils are located outside the excitation coil and are arranged sequentially along the circumference of the excitation coil.

6. The pipe-penetrating rotating eddy current array detection device according to claim 1, characterized in that, The two excitation coils are spaced apart along the winding axis and form a gap; The orthographic projection of the detection coil on the mounting portion falls within the gap.

7. The pipe-penetrating rotating eddy current array detection device according to claim 6, characterized in that, The two excitation coils are arranged symmetrically along the center of the gap.

8. The pipe-penetrating rotating eddy current array detection device according to claim 1, characterized in that, The mounting part includes a magnetic yoke and a connecting structure. The sidewall of the magnetic yoke is provided with a mounting groove along the circumference. The connecting structure is connected to the magnetic yoke and has a connecting end located outside the mounting groove. The orthographic projection of the connecting end on the magnetic yoke falls within the mounting groove. The two excitation coils are located on the bottom wall of the mounting groove, and the detection coil is located at the connection end.

9. The pipe-penetrating rotating eddy current array detection device according to claim 1, characterized in that, The detection coil is connected to an amplification and detection circuit unit, which is electrically connected to an industrial control computer.

10. A method for detecting pipe-penetrating rotating eddy current arrays, applied to the pipe-penetrating rotating eddy current array detection device as described in any one of claims 1-9, characterized in that, include: The current supplied to the two excitation coils is gradually increased from zero, and the induced current signal of the detection coil is acquired until the induced current signal first increases and then decreases with the current supplied to the two excitation coils. Obtain the current values ​​sent to the two excitation coils at the turning point of the induced current signal to obtain the preset current value; When the pipe-through rotating eddy current array detection device detects the ferromagnetic component to be tested, the current value supplied to the two excitation coils is controlled to be the preset current value.

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