Multi-mode eddy current internal detection probe and method for rapid detection of pipeline defects

Abstract

The invention belongs to the technical field of pipeline defect detection, and particularly relates to a multi-mode eddy current internal detection probe and method for rapid detection of pipeline defects. The invention relates to a multi-mode eddy current internal detection probe for rapid detection of pipeline defects. The multi-mode eddy current internal detection probe comprises a probe shell, a shell cover, a PVC (Polyvinyl Chloride) framework, a detection coil, an excitation coil and a strong magnetic permanent magnet, the excitation coil is wound on the outer side of the PVC framework, the detection coil is wound on the outer side of the excitation coil, and the strong magnetic permanent magnet is located on the inner side of the PVC framework; the excitation coil is used for exciting induced eddy current, the strong magnetic permanent magnet is used for generating motional eddy current, and the detection coil is used for receiving two eddy current signals. According to the eddy current probe, the strong magnetic permanent magnet which is perpendicular to the section of the coil is added in the framework of the eddy current probe, and the dynamic eddy current generated by the high-speed movement of the strong magnetic permanent magnet relative to the pipeline is superposed into the induction eddy current of eddy current detection, so that the eddy current detection efficiency is improved, and the signal strength and sensitivity of eddy current detection can be ensured; and accurate, efficient and rapid detection of a long-distance pipeline is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of pipeline defect detection, and in particular relates to a multi-modal eddy current internal detection probe and method for rapid pipeline defect detection. Background Art

[0002] Pipelines are one of the main technical equipment in heavy industrial fields such as energy and chemical industry, and are the lifeline of the national economy. Taking long-distance oil and gas pipelines and urban gas pipelines as examples, various defects will inevitably occur during the production and service process, such as welding defects, stress corrosion cracks, fluid medium corrosion / erosion thinning, etc., so it is very important to conduct regular and irregular non-destructive testing and evaluation on them. However, for buried pipelines, it is often difficult to detect defects from the outer wall of the pipeline, and the development of advanced pipeline internal detection systems is of great importance. In addition, for long-distance pipelines such as long-distance oil and gas pipelines and urban gas pipelines, the current operating speed of internal detectors is generally controlled within 5m / s, which is inefficient. In order to improve the detection efficiency, it is often necessary to use a rapid scanning method to detect defects in the pipeline.

[0003] Eddy current testing is an electromagnetic nondestructive testing method for defect detection based on the principle of electromagnetic induction. It has the advantages of high surface / near-surface defect detection capability, non-contact, and rapid scanning. Therefore, using eddy current testing methods to detect pipeline defects is an efficient method. As mentioned above, due to the long distance and buried nature of long-distance pipelines, eddy current detection equipment and probes need to be loaded on the pipeline internal detector for rapid detection. At this time, the operating speed of the internal detector is greater than 10m / s. At such a high operating speed, the detection signal of the existing eddy current detection probe will be greatly affected, the signal strength will be weakened, and it will even be annihilated by the noise signal, which cannot meet the sensitivity requirements for rapid detection of long-distance pipelines. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a multi-modal eddy current internal detection probe and method for rapid detection of pipeline defects. By adding a strong magnetic permanent magnet placed perpendicular to the coil cross section in the skeleton of the eddy current probe, the motional eddy currents generated by the high-speed movement of the magnet relative to the pipeline are superimposed on the induced eddy currents of the eddy current detection. While improving the eddy current detection efficiency, the signal strength and sensitivity of the eddy current detection can be guaranteed, thereby achieving accurate, efficient and rapid detection of long-distance pipelines.

[0005] The technical solution of the present invention is: a multi-modal eddy current internal detection probe for rapid detection of pipeline defects, comprising a probe shell, a shell cover, a PVC frame, a detection coil, an excitation coil and a strong magnetic permanent magnet; the probe shell and the shell cover are connected in a snap-fit ​​form, and a shell cover lead-in port is provided at the center of the shell cover; the excitation coil is wound around the outside of the PVC frame, the detection coil is wound around the outside of the excitation coil, and the strong magnetic permanent magnet is located on the inside of the PVC frame; the excitation coil is used to excite induced eddy currents, the strong magnetic permanent magnet is used to generate motional eddy currents, and the detection coil is used to receive two eddy current signals.

[0006] The center of the PVC skeleton is provided with a central through hole, a strong permanent magnet is arranged in the central through hole, a PVC skeleton lead-in port is arranged on the top of the PVC skeleton, a skeleton groove is arranged on the side of the PVC skeleton, and an excitation coil and a detection coil are arranged in the skeleton groove.

[0007] A method for rapid detection of pipeline defects, using the multi-modal eddy current internal detection probe for rapid detection of pipeline defects as described above, comprises the following steps: S1: The multi-modal eddy current internal detection probe for rapid pipeline defect detection is rapidly run and scanned in the pipeline test piece 7 along with the eddy current detection system, and the running speed v>10m / s; S2: A steady-state sinusoidal excitation current is passed through the excitation coil, which generates an alternating magnetic field around the excitation coil. The alternating magnetic field will induce alternating eddy currents in the pipe specimen 7, namely, induced eddy currents. , the induced eddy current generates induced electromotive force ; S3: Alternating magnetic field around the exciting coil The generated magnetic flux lines will be cut by the relatively moving pipeline test piece 7, that is, the conductor cuts the magnetic flux lines of the alternating magnetic field, thus forming motional eddy currents in the pipeline test piece 7, which generate motional electromotive force in the detection coil. ; S4: Constant magnetic field generated by strong permanent magnets The magnetic flux lines will also be cut by the relatively moving pipeline test piece 7, that is, the conductor cuts the magnetic flux lines of the constant magnetic field, thus forming motional eddy currents in the pipeline test piece 7, which will generate enhanced motional electromotive force in the detection coil. ; S5: By measuring the induced electromotive force in steps S2~S4 , Motional EMF and enhanced motional electromotive force Voltage signal after superposition of three electromotive forces U , According to the change of the voltage signal after the potential superposition, the long-distance pipeline can be quickly detected to determine the size and position of the pipeline inner wall defect 8 in the pipeline test piece 7.

[0008] In step S2, the alternating magnetic field of the excitation coil Induced eddy currents are formed in the pipe specimen 7 , the induced electromotive force generated The specific calculation formula is: (1) In the formula, is the alternating magnetic field generated by the sinusoidal excitation current in the excitation coil, t is the time, and S is the area of ​​the detection coil.

[0009] In step S3, the alternating magnetic field of the excitation coil The relative motion with the pipeline specimen 7 generates the motional electromotive force The specific calculation formula is: (2) In the formula, is the alternating magnetic field generated by the sinusoidal excitation current in the excitation coil, t is the time, C is the circumference of the detection coil, l It is the length unit of the detection coil.

[0010] In step S4, the constant magnetic field of the strong permanent magnet The relative motion with the pipeline specimen 7 generates an enhanced motional electromotive force The specific calculation formula is: (3) In the formula, is the constant magnetic field generated by the permanent magnet, t is the time, C is the circumference of the detection coil, l It is the length unit of the detection coil.

[0011] The technical effects of the present invention are as follows: 1. The present invention adds a permanent magnet placed perpendicular to the coil cross section in the PVC frame of the eddy current probe, utilizes the motional eddy current generated by the high-speed movement of the probe in the pipeline, and superimposes it on the induced eddy current of the eddy current detection for signal compensation, thereby ensuring the signal strength and sensitivity of the eddy current detection; 2. The multi-modal eddy current internal detection probe for rapid detection of pipeline defects of the present invention is loaded on the pipeline internal detector to perform high-speed detection of the pipeline, has high detection efficiency and can achieve long-distance detection.

[0012] The following is a further description with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The present invention is a schematic diagram of the structure of a multi-modal eddy current internal testing probe for rapid detection of pipeline defects according to an embodiment of the present invention.

[0014] Figure 2 It is a schematic top view of the structure of the PVC skeleton according to an embodiment of the present invention.

[0015] Figure 3 It is a schematic diagram of the front view of the structure of the PVC skeleton according to an embodiment of the present invention.

[0016] Figure 4 Schematic diagram of rapid detection of probe according to an embodiment of the present invention.

[0017] Figure 5 This is a system diagram of a rapid probe detection method according to an embodiment of the present invention.

[0018] Figure 6 This is a diagram of the rapid detection results of an embodiment of the present invention.

[0019] Figure numerals: 1-probe housing, 2-housing cover, 21-housing cover lead-in port, 3-PVC skeleton, 31-PVC skeleton lead-in port, 32-skeleton groove, 33-center through hole, 4-detection coil, 5-excitation coil, 6-strong permanent magnet, 7-pipeline specimen, 8-defects on the inner wall of the pipeline. DETAILED DESCRIPTION Example 1

[0020] like Figure 1 As shown, a multi-modal eddy current internal detection probe for rapid detection of pipeline defects includes a probe housing 1, a housing cover 2, a PVC frame 3, a detection coil 4, an excitation coil 5 and a strong magnetic permanent magnet 6; the probe housing 1 and the housing cover 2 are connected in a snap-fit ​​form, and a housing cover lead-in port 21 is provided at the center of the housing cover 2; the excitation coil 5 is wound around the outside of the PVC frame 3, the detection coil 4 is wound around the outside of the excitation coil 5, and the strong magnetic permanent magnet 6 is located on the inside of the PVC frame 3; the excitation coil 5 is used to excite induced eddy currents, the strong magnetic permanent magnet 6 is used to generate motional eddy currents, and the detection coil 4 is used to receive two eddy current signals.

[0021] During actual use, the present invention adds a permanent magnet placed perpendicular to the coil cross section in the PVC frame of the eddy current probe, utilizes the motional eddy current generated by the high-speed movement of the probe in the pipeline, and superimposes it on the induced eddy current of the eddy current detection for signal compensation, thereby ensuring the signal strength and sensitivity of the eddy current detection; the multi-modal eddy current internal detection probe for rapid detection of pipeline defects of the present invention is loaded on the pipeline internal detector to perform high-speed detection of the pipeline, has high detection efficiency and can achieve long-distance detection. Example 2

[0022] Preferably, on the basis of Example 1, in this embodiment, Figure 2 , Figure 3 As shown, a central through hole 33 is provided in the center of the PVC skeleton 3, a strong permanent magnet 6 is provided in the central through hole 33, a PVC skeleton lead opening 31 is provided on the top of the PVC skeleton 3, a skeleton groove 32 is provided on the side of the PVC skeleton 3, and an excitation coil 5 and a detection coil 4 are provided in the skeleton groove 32.

[0023] During actual use, a strong permanent magnet 6 is provided in the central through hole 33, a PVC skeleton lead-in port 31 is provided on the top of the PVC skeleton 3, a skeleton groove 32 is provided on the side of the PVC skeleton 3, and an excitation coil 5 and a detection coil 4 are provided in the skeleton groove 32, so as to ensure that the overall installation structure of the eddy current probe is compact and flat. Example 3

[0024] A method for rapid detection of pipeline defects, such as Figure 4 , Figure 5 As shown, using the multi-modal eddy current internal detection probe for rapid pipeline defect detection as described above includes the following steps: S1: The multi-modal eddy current internal detection probe for rapid pipeline defect detection is rapidly run and scanned in the pipeline test piece 7 along with the eddy current detection system, and the running speed v>10m / s; S2: A steady-state sinusoidal excitation current is passed through the excitation coil 5, which generates an alternating magnetic field around the excitation coil 5. The alternating magnetic field will induce alternating eddy currents in the pipe specimen 7, namely, induced eddy currents. , the induced eddy current generates induced electromotive force ; S3: Alternating magnetic field around the exciting coil 5 The generated magnetic flux lines will be cut by the relatively moving pipeline test piece 7, that is, the conductor cuts the magnetic flux lines of the alternating magnetic field, thus forming motional eddy currents in the pipeline test piece 7, which generate motional electromotive force in the detection coil 4. ; S4: Constant magnetic field generated by strong permanent magnet 6 The magnetic flux lines will also be cut by the relatively moving pipeline test piece 7, that is, the conductor cuts the magnetic flux lines of the constant magnetic field, thus forming motional eddy currents in the pipeline test piece 7, which will generate enhanced motional electromotive force in the detection coil 4. ; S5: By measuring the induced electromotive force in steps S2~S4 , Motional EMF and enhanced motional electromotive force Voltage signal after superposition of three electromotive forces U , According to the change of the voltage signal after the potential superposition, the long-distance pipeline can be quickly detected to determine the size and position of the pipeline inner wall defect 8 in the pipeline test piece 7.

[0025] In step S2, the alternating magnetic field of the excitation coil 5 Induced eddy currents are formed in the pipe specimen 7 , the induced electromotive force generated The specific calculation formula is: (1) In the formula, is the alternating magnetic field generated by the sinusoidal excitation current in the excitation coil 5, t is the time, and S is the area of ​​the detection coil 4.

[0026] In step S3, the alternating magnetic field of the excitation coil 5 The relative motion with the pipeline specimen 7 generates the motional electromotive force The specific calculation formula is: (2) In the formula, is the alternating magnetic field generated by the sinusoidal excitation current in the excitation coil 5, t is the time, C is the circumference of the detection coil 4, l It is the length unit of the detection coil 4.

[0027] In step S4, the constant magnetic field of the strong permanent magnet 6 The relative motion with the pipeline specimen 7 generates an enhanced motional electromotive force The specific calculation formula is: (3) In the formula, is the constant magnetic field generated by the permanent magnet, t is the time, C is the circumference of the detection coil 4, l It is the length unit of the detection coil 4. Example 4

[0028] Using a multi-modal eddy current internal detection probe for rapid detection of pipeline defects as described in Example 1, and a pipeline defect rapid detection method as described in Example 3, a pipeline sample with pipeline defects was rapidly detected at detection speeds of 10 m / s and 15 m / s, respectively. The detection results are as follows: Figure 6 As shown. Figure 6It can be seen that at the pipeline defect (position 0 in the figure), the detection signal has an obvious concave feature, which proves that the multi-modal eddy current internal detection probe for rapid detection of pipeline defects of the present invention can accurately identify pipeline defects at high speed (detection speed ≥ 10m / s), while the detection signal of the existing eddy current detection probe cannot extract effective features and cannot identify pipeline defects during high-speed detection (detection speed ≥ 10m / s).

[0029] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A multi-modal eddy current internal detection probe for rapid detection of pipeline defects, characterized in that: The probe housing (1), the housing cover (2), the PVC frame (3), the detection coil (4), the excitation coil (5) and the strong permanent magnet (6); the probe housing (1) and the housing cover (2) are connected in a snap-fit ​​manner, and the center of the housing cover (2) is provided with a housing cover lead-in opening (21); the excitation coil (5) is wound around the outside of the PVC frame (3), the detection coil (4) is wound around the outside of the excitation coil (5), and the strong permanent magnet (6) is located on the inside of the PVC frame (3); the excitation coil (5) is used to excite induced eddy currents, the strong permanent magnet (6) is used to generate motional eddy currents, and the detection coil (4) is used to receive two eddy current signals.

2. According to claim 1, a multi-modal eddy current internal inspection probe for rapid detection of pipeline defects is characterized by: The PVC skeleton (3) is provided with a central through hole (33) at its center, a strong permanent magnet (6) is provided in the central through hole (33), a PVC skeleton lead-in port (31) is provided at the top of the PVC skeleton (3), a skeleton groove (32) is provided on the side of the PVC skeleton (3), and an excitation coil (5) and a detection coil (4) are provided in the skeleton groove (32).

3. A method for rapid detection of pipeline defects, using a multi-modal eddy current internal detection probe for rapid detection of pipeline defects as claimed in claim 1, characterized in that: The following steps are involved: S1: The multi-modal eddy current internal detection probe for rapid pipeline defect detection is rapidly run and scanned in the pipeline test piece (7) along with the eddy current detection system, with the running speed v>10m / s; S2: A steady-state sinusoidal excitation current is passed through the excitation coil (5), which generates an alternating magnetic field around the excitation coil (5). The alternating magnetic field will induce alternating eddy currents in the pipe specimen (7), namely, induced eddy currents. , the induced eddy current generates induced electromotive force ; S3: Alternating magnetic field around the excitation coil (5) The generated magnetic flux lines will be cut by the relatively moving pipeline test piece (7), that is, the conductor cuts the magnetic flux lines of the alternating magnetic field, thereby forming motional eddy currents in the pipeline test piece (7), and the motional eddy currents generate motional electromotive force in the detection coil (4). ; S4: Constant magnetic field generated by strong permanent magnet (6) The magnetic flux lines will also be cut by the relatively moving pipeline test piece (7), that is, the conductor cuts the magnetic flux lines of the constant magnetic field, thus also forming motional eddy currents in the pipeline test piece (7), and the motional eddy currents will generate enhanced motional electromotive force in the detection coil (4). ; S5: By measuring the induced electromotive force in steps S2~S4 , Motional EMF and enhanced motional electromotive force Voltage signal after superposition of three electromotive forces U , According to the change of the voltage signal after the potential superposition, the long-distance pipeline can be quickly detected to determine the size and position of the pipeline inner wall defect (8) in the pipeline test piece (7).

4. A pipeline defect rapid detection method according to claim 3, characterized in that: In step S2, the alternating magnetic field of the excitation coil (5) Induced eddy currents are generated in the pipe specimen (7) , the induced electromotive force generated The specific calculation formula is: (1) In the formula, is the alternating magnetic field generated by the sinusoidal excitation current in the excitation coil (5), t is the time, and S is the area of ​​the detection coil (4).

5. A pipeline defect rapid detection method according to claim 3, characterized in that: In step S3, the alternating magnetic field of the excitation coil (5) The relative motion with the pipe specimen (7) generates a motional electromotive force The specific calculation formula is: (2) In the formula, is the alternating magnetic field generated by the sinusoidal excitation current in the excitation coil (5), t is the time, C is the circumference of the detection coil (4), l is the length unit of the detection coil (4).

6. A pipeline defect rapid detection method according to claim 3, characterized in that: In step S4, the constant magnetic field of the strong permanent magnet (6) The relative motion with the pipe specimen (7) generates an enhanced motional electromotive force The specific calculation formula is: (3) In the formula, is the constant magnetic field generated by the permanent magnet, t is the time, C is the circumference of the detection coil (4), l is the length unit of the detection coil (4).

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