Apparatus and method for lift-off resitant detection of circumferential weld defects in pipe

Abstract

An apparatus and method for lift-off resitant detection of circumferential weld defects in a pipe. The apparatus sends alternating current sinusoidal signals to a first orthogonal excitation unit (131) and a second orthogonal excitation unit (132) by means of an excitation signal generator (110), so that a first excitation coil (1311) and a second excitation coil (1312) which are arranged orthogonal to one another and are comprised in the first orthogonal excitation unit (131), as well as a third excitation coil (1321) and a fourth excitation coil (1322) which are arranged orthogonal to one another and are comprised in the second orthogonal excitation unit (132), generate a composite alternating magnetic field. When the apparatus passes over a circumferential weld on a pipe, due to the fact that defects at different positions or angles in the circumferential weld on the pipe can vertically cut magnetic lines in the composite alternating magnetic field, rapid and accurate detection of circumferential weld defects in the pipe at different positions or angles can be implemented by means of detecting induced voltage amplitudes generated by vertical cutting, so that detection efficiency is improved and detection costs are reduced.

Description

Device and method for detecting defects in circumferential welds of pipelines that resist lift-off

[0001] This application claims priority to Chinese Patent Application No. 202411215115.2, filed with the Chinese Patent Office on September 2, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of pipeline inspection technology, for example to a device and method for detecting defects in pipeline circumferential welds that resist lift-off. Background Technology

[0003] Due to its advantages of speed, safety, and economy, pipeline transportation of oil and natural gas has become one of the main methods for transporting oil and gas resources. Oil and gas pipelines are crucial foundational equipment in the oil and gas transportation system. However, influenced by factors such as on-site welding construction, operating environment, and technical understanding, circumferential welds have always been weak points in pipelines, and circumferential weld cracking has become one of the main failure modes. Therefore, defect detection of pipeline circumferential welds is particularly important to ensure the rapid and safe transportation of oil and gas resources.

[0004] In related technologies, defect detection methods for pipeline circumferential welds can generally be divided into internal pipeline inspection techniques and external pipeline inspection techniques. On the one hand, internal pipeline inspection techniques are based on magnetic flux leakage (MFL) detection, but MFL can only detect some volumetric defects in circumferential welds and is greatly affected by the defect angle. For example, if the circumferential weld defect does not cut the induced magnetic lines of force, the defect cannot be accurately detected. On the other hand, external pipeline inspection techniques are usually combined with excavation verification, but this involves a large workload, low recognition rate, long inspection cycle, and poor timeliness. Summary of the Invention

[0005] This application provides a device and method for detecting defects in pipe circumferential welds that resist lift-off, which can quickly and accurately detect defects in pipe circumferential welds at different positions and angles, improve detection efficiency, and reduce detection costs.

[0006] In a first aspect, this application provides a device for detecting defects in circumferential welds of pipelines that resist lift-off. The device includes: an excitation signal generator, a time-division multiplexing module, at least one excitation module, a signal acquisition module, and a signal processing module. The excitation signal generator is connected to the time-division multiplexing module, the time-division multiplexing module is connected to the excitation module, the excitation module is connected to the signal acquisition module, and the signal acquisition module is connected to the signal processing module. The excitation module includes a first orthogonal excitation unit, a second orthogonal excitation unit, and a detection unit. Both the first and second orthogonal excitation units are connected to the time-division multiplexing module. The first orthogonal excitation unit includes a first excitation coil and a second excitation coil arranged orthogonally to each other. The second orthogonal excitation unit includes a third excitation coil and a fourth excitation coil arranged orthogonally to each other. The detection unit is connected to the signal acquisition module. The excitation signal generator is configured to output an AC sinusoidal signal to the time-division multiplexing module. The time-division multiplexing module is configured to send a first AC sinusoidal signal to the first excitation coil, a second AC sinusoidal signal to the second excitation coil, and a third AC sinusoidal signal to the third excitation coil, based on the AC sinusoidal signal. A fourth AC sinusoidal signal is sent to the fourth excitation coil to form a composite alternating magnetic field, which includes the magnetic field formed by the first, second, third, and fourth excitation coils. The second AC sinusoidal signal is obtained by shifting the phase of the first AC sinusoidal signal by 90°. The third AC sinusoidal signal is a signal with the opposite direction and the same amplitude as the first AC sinusoidal signal. The fourth AC sinusoidal signal is obtained by shifting the phase of the third AC sinusoidal signal by 90°. The detection unit is configured to acquire the induced voltage amplitude of the pipe circumferential weld to be detected when the excitation module passes the circumferential weld to be detected, and to send the induced voltage amplitude to the signal acquisition module. The signal acquisition module is configured to determine the identification information of the pipe circumferential weld to be detected, and to send the induced voltage amplitude and identification information of the pipe circumferential weld to the signal processing module. The signal processing module is configured to determine the defect detection result of the pipe circumferential weld to be detected based on the induced voltage amplitude and identification information of the pipe circumferential weld to be detected. The defect detection result includes normal and abnormal.

[0007] In some embodiments, the above-described apparatus includes a plurality of excitation modules arranged in a circumferential array along the time-division multiplexing module.

[0008] In some embodiments, the signal acquisition module also communicates with the time-division multiplexing module, and the signal acquisition module is further configured to determine the identification information of the target excitation module for acquiring the induced voltage amplitude of the pipe circumferential weld to be detected, wherein the target excitation module is one of a plurality of excitation modules; and is configured to send the identification information of the target excitation module to the signal processing module, wherein the signal processing module is configured to determine the defect location of the pipe circumferential weld to be detected based on the identification information of the target excitation module.

[0009] In some embodiments, the first excitation coil, the second excitation coil, the third excitation coil, and the fourth excitation coil are rectangular coils, and the detection unit includes a circular coil.

[0010] In some embodiments, the excitation signal generator includes a sine wave generator and a phase shifter; the excitation signal generator is configured to output a fifth AC sine wave signal and a sixth AC sine wave signal to the time-division multiplexing module, wherein the fifth AC sine wave signal and the sixth AC sine wave signal have opposite signal directions and the same amplitude; the time-division multiplexing module is configured to: obtain a first AC sine wave signal and a second AC sine wave signal based on the fifth AC sine wave signal, obtain a third AC sine wave signal and a fourth AC sine wave signal based on the sixth AC sine wave signal, send the first AC sine wave signal to the first excitation coil, send the second AC sine wave signal to the second excitation coil, send the third AC sine wave signal to the third excitation coil, and send the fourth AC sine wave signal to the fourth excitation coil.

[0011] In some embodiments, the signal processing module is configured to determine that the defect detection result of the pipe circumferential weld is abnormal when the amplitude of the induced voltage of the pipe circumferential weld to be detected is greater than a preset threshold.

[0012] In some embodiments, the signal processing module is configured to determine that the defect detection result of the pipe circumferential weld is normal when the amplitude of the induced voltage of the weld to be detected is less than or equal to a preset threshold.

[0013] In some embodiments, the device further includes a protective housing, and the excitation signal generator, time-division multiplexing module, excitation module, signal acquisition module, and signal processing module are disposed inside the protective housing.

[0014] In some embodiments, the device further includes an arc-shaped ceramic plate disposed at the bottom of the protective shell.

[0015] Secondly, this application provides a method for detecting defects in circumferential welds of pipelines designed for lifting-off, applied to a device for detecting defects in circumferential welds of pipelines designed for lifting-off. The device includes an excitation signal generator, a time-division multiplexing module, at least one excitation module, a signal acquisition module, and a signal processing module. The excitation signal generator is connected to the time-division multiplexing module, the time-division multiplexing module is connected to the excitation module, the excitation module is connected to the signal acquisition module, and the signal acquisition module is connected to the signal processing module. The excitation module includes a first orthogonal excitation unit, a second orthogonal excitation unit, and a detection unit. Both the first and second orthogonal excitation units are connected to the time-division multiplexing module. The first orthogonal excitation unit includes a first excitation coil and a second excitation coil arranged orthogonally to each other. The second orthogonal excitation unit includes a third excitation coil and a fourth excitation coil arranged orthogonally to each other. The detection unit is connected to the signal acquisition module.

[0016] The above method includes: an excitation signal generator outputting an AC sinusoidal signal to a time-division multiplexing module; the time-division multiplexing module sending a first AC sinusoidal signal to a first excitation coil, a second AC sinusoidal signal to a second excitation coil, a third AC sinusoidal signal to a third excitation coil, and a fourth AC sinusoidal signal to a fourth excitation coil according to the AC sinusoidal signal, to form a composite alternating magnetic field, the composite alternating magnetic field including the magnetic field formed by the first excitation coil, the second excitation coil, the third excitation coil, and the fourth excitation coil; wherein, the second AC sinusoidal signal is the signal obtained after phase-shifting the first AC sinusoidal signal by 90°, and the third AC sinusoidal signal is the signal obtained by phase-shifting the first AC sinusoidal signal. Signals with opposite directions and the same amplitude; the fourth AC sinusoidal signal is obtained by shifting the phase of the third AC sinusoidal signal by 90°; when the excitation module passes the circumferential weld of the pipeline to be inspected, the detection unit acquires the induced voltage amplitude of the circumferential weld of the pipeline to be inspected and sends the induced voltage amplitude to the signal acquisition module; the signal acquisition module determines the identification information of the circumferential weld of the pipeline to be inspected and sends the induced voltage amplitude and identification information of the circumferential weld of the pipeline to be inspected to the signal processing module; the signal processing module determines the defect detection result of the circumferential weld of the pipeline to be inspected based on the induced voltage amplitude and identification information of the circumferential weld of the pipeline to be inspected, and the defect detection result includes normal and abnormal. Attached Figure Description

[0017] Figure 1 is a hardware structure block diagram of a pipe circumferential weld defect detection device provided in an embodiment of this application;

[0018] Figure 2 is a schematic diagram of the hardware structure of a pipe circumferential weld defect detection device provided in an embodiment of this application;

[0019] Figure 3 is a schematic diagram of an AC sinusoidal signal according to an embodiment of this application;

[0020] Figure 4 is a schematic diagram of induced magnetic field lines of a composite alternating magnetic field cut by a defect at different angle positions, as shown in an embodiment of this application.

[0021] Figure 5 is a schematic diagram showing the connection between multiple excitation modules and a time-division multiplexing module according to an embodiment of this application;

[0022] Figure 6 is a pulse sequence diagram of a time-division multiplexing module according to an embodiment of this application;

[0023] Figure 7 is a flowchart illustrating a method for detecting defects in the circumferential weld of a pipeline under lifting-off conditions, according to an embodiment of this application. 110, Excitation signal generator; 120, Time-division multiplexing module; 130, Excitation module; 131, First orthogonal excitation unit; 1311, First excitation coil; 1312, Second excitation coil; 132, Second orthogonal excitation unit; 1321, Third excitation coil; 1322, Fourth excitation coil; 133, Detection unit; 140, Signal acquisition module; 150, Signal processing module; 160, Protective shell; 170, Arc-shaped ceramic plate. Detailed Implementation

[0024] The embodiments of this application will now be described with reference to the accompanying drawings. In this description, unless otherwise stated, " / " indicates that the objects before and after it are in an "or" relationship; for example, A / B can represent A or B. "And / or" in this application describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone, where A and B can be singular or plural. Furthermore, unless otherwise stated, "multiple" in this description refers to two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0025] In the embodiments of this application, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" do not necessarily imply that they are different.

[0026] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as having a greater advantage than other embodiments or designs. Rather, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner to facilitate understanding.

[0027] This application provides a device for detecting defects in circumferential welds of pipelines that resist lift-off. The device includes: an excitation signal generator, a time-division multiplexing module, at least one excitation module, a signal acquisition module, and a signal processing module. The excitation signal generator is connected to the time-division multiplexing module, the time-division multiplexing module is connected to the excitation module, the excitation module is connected to the signal acquisition module, and the signal acquisition module is connected to the signal processing module. The excitation module includes a first orthogonal excitation unit, a second orthogonal excitation unit, and a detection unit. The first and second orthogonal excitation units are connected to the time-division multiplexing module. The first orthogonal excitation unit includes a first excitation coil and a second excitation coil arranged orthogonally to each other. The second orthogonal excitation unit includes a third excitation coil and a fourth excitation coil arranged orthogonally to each other. The detection unit is connected to the signal acquisition module. The excitation signal generator is configured to output an AC sinusoidal signal to the time-division multiplexing module. The time-division multiplexing module is configured to send a first AC sinusoidal signal to the first excitation coil, a second AC sinusoidal signal to the second excitation coil, a third AC sinusoidal signal to the third excitation coil, and a fourth AC sinusoidal signal to the third excitation coil, based on the AC sinusoidal signal. Four excitation coils transmit a fourth AC sinusoidal signal to form a composite alternating magnetic field, which includes the magnetic field formed by the first, second, third, and fourth excitation coils. The second AC sinusoidal signal is obtained by shifting the phase of the first AC sinusoidal signal by 90°. The third AC sinusoidal signal is a signal with the opposite direction and the same amplitude as the first AC sinusoidal signal. The fourth AC sinusoidal signal is obtained by shifting the phase of the third AC sinusoidal signal by 90°. The detection unit is configured to acquire the induced voltage amplitude of the pipe circumferential weld to be detected when the excitation module passes through it, and to send the induced voltage amplitude to the signal acquisition module. The signal acquisition module is configured to determine the identification information of the pipe circumferential weld to be detected, and to send the induced voltage amplitude and identification information of the pipe circumferential weld to the signal processing module. The signal processing module is configured to determine the defect detection result of the pipe circumferential weld to be detected based on the induced voltage amplitude and identification information. The defect detection result includes normal and abnormal results.

[0028] The device provided in this application sends an AC sinusoidal signal to the first orthogonal excitation unit and the second orthogonal excitation unit via an excitation signal generator. This causes the first excitation coil and the second excitation coil, which are orthogonally arranged in the first orthogonal excitation unit, and the third excitation coil and the fourth excitation coil, which are orthogonally arranged in the second orthogonal excitation unit, to generate a composite alternating magnetic field. When the device passes through the pipe circumferential weld, defects located at different positions and angles of the pipe circumferential weld can vertically cut the induced magnetic lines of force in the composite alternating magnetic field. By detecting the amplitude of the induced voltage generated by the vertical cutting, rapid and accurate detection of defects in the pipe circumferential weld at different positions and angles can be achieved, thereby improving detection efficiency and reducing detection costs.

[0029] In summary, the device provided in this application detects the amplitude of the induced voltage generated by multiple excitation coils, uses a circumferentially symmetrical differential configuration to set up multiple excitation units, and sends different AC sinusoidal signals to each excitation unit. This achieves physical filtering of the detection signal at large lift-off points and full coverage detection of the rotating excitation magnetic field, solving the problem of detecting defects in circumferential welds at different angles. This application can effectively improve the sensitivity and reliability of defect detection and greatly reduce the missed detection rate of pipeline circumferential weld defects.

[0030] In this application, "lift-off" refers to the change or instantaneous separation of the non-contact distance between the defect detection device and the surface of the pipe circumferential weld, which can lead to attenuation or distortion of the detection signal. "Anti-lift-off" refers to reducing the impact of this phenomenon on the detection results.

[0031] The following description, in conjunction with the accompanying drawings, illustrates the anti-lift-off pipeline circumferential weld defect detection device provided in the embodiments of this application.

[0032] Figure 1 is a hardware structure block diagram of a pipe circumferential weld defect detection device according to an embodiment of this application. The pipe circumferential weld defect detection device 100 (hereinafter referred to as defect detection device 100) includes: an excitation signal generator 110, a time-division multiplexing module 120, at least one excitation module 130, a signal acquisition module 140, and a signal processing module 150; the excitation signal generator 110 is connected to the time-division multiplexing module 120, the time-division multiplexing module 120 is connected to the excitation module 130, the excitation module 130 is connected to the signal acquisition module 140, and the signal acquisition module 140 is connected to the signal processing module 150.

[0033] Referring to Figure 2, which is a schematic diagram of a defect detection device according to an embodiment of this application, the excitation module 130 includes a first orthogonal excitation unit 131, a second orthogonal excitation unit 132, and a detection unit 133. The first orthogonal excitation unit 131 and the second orthogonal excitation unit 132 are connected to the time-division multiplexing module 120. The first orthogonal excitation unit 131 includes a first excitation coil 1311 and a second excitation coil 1312 arranged orthogonally to each other. The second orthogonal excitation unit 132 includes a third excitation coil 1321 and a fourth excitation coil 1322 arranged orthogonally to each other. The detection unit 133 is connected to the signal acquisition module 140.

[0034] Optionally, referring to Figure 2, the defect detection device 100 also includes a protective shell 160, and the excitation signal generator 110, time-division multiplexing module 120, excitation module 130, signal acquisition module 140 and signal processing module 150 are all disposed inside the protective shell 160.

[0035] In some embodiments, the signal acquisition module 140, signal processing module 150, excitation signal generator 110, and time-division multiplexing module 120 may also be disposed outside the protective housing 160.

[0036] This application embodiment provides a protective shell 160 to carry and protect the various components included in the defect detection device 100, thereby achieving the encapsulation of the internal modules of the defect detection device 100.

[0037] In some embodiments, referring to FIG2, the defect detection device 100 further includes an arc-shaped ceramic plate 170 disposed at the bottom of the protective shell 160.

[0038] For example, the arc-shaped ceramic plate 170 is configured to form a buffer between the defect detection device 100 and the circumferential weld of the pipe to be inspected, reducing the impact force between the defect detection device 100 and the circumferential weld, thereby protecting the defect detection device 100. The arc-shaped ceramic plate 170, through a contoured design of the weld toe portion of the circumferential weld, reduces the vibration of the defect detection device 100 as it passes through the circumferential weld, achieving a smooth transition. The contoured structure of the arc-shaped ceramic plate 170 ensures the fit between the defect detection device 100 and the circumferential weld and its weld toe portion. Furthermore, the ceramic material of the arc-shaped ceramic plate 170 enhances the wear resistance and stability of the defect detection device 100 during long-distance operation. It can also be understood that the arc-shaped ceramic sheet 170 is used as the base of the defect detection device 100. Through the contouring method, the defect detection device 100 can transition more smoothly when passing through the circumferential weld reinforcement, reducing the lift-off value of the defect detection device 100 and reducing vibration. It also has better fit and wear resistance for the weld toe area, which can effectively extend the product service life of the defect detection device 100.

[0039] In some embodiments, referring to FIG2, the first excitation coil 1311, the second excitation coil 1312, the third excitation coil 1321 and the fourth excitation coil 1322 are rectangular coils, wherein each rectangular coil includes two long sides and two short sides. The two short sides of the first excitation coil 1311 and the second excitation coil 1312 are perpendicular to each other and intersect, and the two short sides of the third excitation coil 1321 and the fourth excitation coil 1322 are perpendicular to each other and intersect.

[0040] The excitation signal generator 110 is configured to output an AC sinusoidal signal to the time-division multiplexing module 120; the time-division multiplexing module 120 is configured to send a first AC sinusoidal signal to the first excitation coil 1311, a second AC sinusoidal signal to the second excitation coil 1312, a third AC sinusoidal signal to the third excitation coil 1321, and a fourth AC sinusoidal signal to the fourth excitation coil 1322 according to the AC sinusoidal signal, so as to form a composite alternating magnetic field, which includes the magnetic field formed by the first excitation coil 1311, the second excitation coil 1312, the third excitation coil 1321, and the fourth excitation coil 1322;

[0041] The second AC sinusoidal signal is obtained by shifting the phase of the first AC sinusoidal signal by 90°. The third AC sinusoidal signal is a signal with the opposite direction and the same amplitude as the first AC sinusoidal signal. The fourth AC sinusoidal signal is obtained by shifting the phase of the third AC sinusoidal signal by 90°.

[0042] In one example, the expression for the first AC sinusoidal signal is: In the case of the second AC sinusoidal signal, the expression is: The expression for the third AC sinusoidal signal is: The expression for the fourth AC sinusoidal signal is:

[0043] For example, referring to Figure 3, which is a schematic diagram of an AC sinusoidal signal according to an embodiment of this application, including a first AC sinusoidal signal sin(x), a second AC sinusoidal signal cos(x), a third AC sinusoidal signal -sin(x) and a fourth AC sinusoidal signal -cos(x).

[0044] In one possible implementation, the excitation signal generator 110 includes a sine wave generator and a phase shifter; the excitation signal generator 110 is configured to output a fifth AC sine wave signal and a sixth AC sine wave signal to the time-division multiplexing module 120, wherein the fifth AC sine wave signal and the sixth AC sine wave signal have opposite signal directions and the same amplitude. The time-division multiplexing module 120 is configured to: obtain a first AC sine wave signal and a second AC sine wave signal based on the fifth AC sine wave signal, obtain a third AC sine wave signal and a fourth AC sine wave signal based on the sixth AC sine wave signal, send the first AC sine wave signal to the first excitation coil 1311, send the second AC sine wave signal to the second excitation coil 1312, send the third AC sine wave signal to the third excitation coil 1321, and send the fourth AC sine wave signal to the fourth excitation coil 1322.

[0045] In some embodiments, the sine wave generator is configured to output a stable basic sine wave signal, and the phase shifter is configured to achieve a 90° or 180° phase shift. The sine wave generator and the phase shifter work together to generate a fifth AC sine wave signal and a sixth AC sine wave signal, and output them to the time-division multiplexing module 120 to provide a key signal source for the formation of a composite alternating magnetic field and support full-angle defect detection.

[0046] For example, in this embodiment of the application, by sending different AC sinusoidal signals to the first excitation coil 1311, the second excitation coil 1312, the third excitation coil 1321, and the fourth excitation coil 1322, the magnetic fields generated by the first excitation coil 1311, the second excitation coil 1312, the third excitation coil 1321, and the fourth excitation coil 1322 can be made into a composite alternating magnetic field. The composite alternating magnetic field can also be understood as including two sets of real-time rotating vectors and magnetic fields with opposite directions and the same magnitude. During the normal operation of the defect detection device 100, when the defect detection device 100 passes through the pipe wall of the oil and gas pipeline or a circumferential weld without defects, the difference between the rotating magnetic field signals formed by the first orthogonal excitation unit 131 and the second orthogonal excitation unit 132 at the detection unit 133 is zero; when the defect detection device 100 passes through a circumferential weld with defects, the defect has different effects on the disturbance of the rotating magnetic field of the first orthogonal excitation unit 131 and the second orthogonal excitation unit 132. At this time, the two magnetic field signals obtained by the detection unit 133 show a difference in magnitude, and the amplitude of the induced voltage at the defect can be obtained.

[0047] For example, see Figure 4, which is a schematic diagram of the induced magnetic field lines cut by defects at different angles in a composite alternating magnetic field. Figure 4 includes the cutting process of induced magnetic field lines by circumferential weld defects at four different positions and angles. Since the first orthogonal excitation unit 131 and the second orthogonal excitation unit 132 have induced rotating combined magnetic fields, there will be cases where the defects perpendicularly cut the induced magnetic field lines for circumferential weld defects at different directions and angles, so that the detection unit 133 can obtain the amplitude of the induced voltage. That is, there is a high detection sensitivity for circumferential weld defects at different angles.

[0048] The detection unit 133 is configured to acquire the induced voltage amplitude of the circumferential weld of the pipe to be detected when the excitation module 130 passes through the circumferential weld of the pipe to be detected, and is configured to send the induced voltage amplitude to the signal acquisition module 140.

[0049] In some embodiments, the detection unit 133 includes a circular coil. This circular coil may also be referred to as a detection coil.

[0050] For example, during the operation of the defect detection device 100, the defect detection device 100 moves at a constant speed in the oil and gas pipeline, and the central axis X of the circular coil... iParallel to the radial direction of the pipe, and perpendicular to the axial and circumferential directions of the pipe.

[0051] The signal acquisition module 140 is configured to determine the identification information of the pipe circumferential weld to be detected, and to send the induced voltage amplitude and identification information of the pipe circumferential weld to be detected to the signal processing module 150.

[0052] The signal processing module 150 is configured to determine the defect detection result of the circumferential weld of the pipeline to be inspected based on the induced voltage amplitude and identification information of the circumferential weld. The defect detection result includes normal and abnormal.

[0053] For example, the signal processing module 150 is configured to: determine that the defect detection result of the pipe circumferential weld is abnormal when the induced voltage amplitude of the pipe circumferential weld to be detected is greater than a preset threshold; and determine that the defect detection result of the pipe circumferential weld to be detected is normal when the induced voltage amplitude of the pipe circumferential weld to be detected is less than or equal to the preset threshold.

[0054] The preset threshold can be set according to the actual detection scenario to adapt to the defect detection needs in different scenarios.

[0055] In some embodiments, the defect detection device 100 includes a plurality of excitation modules 130, which are arranged in a circumferential array along the time-division multiplexing module 120.

[0056] Referring to Figure 5, which is a schematic diagram illustrating the connection between multiple excitation modules and a time-division multiplexing module according to an embodiment of this application, the defect detection device 100 includes eight excitation modules 130 arranged in a circumferential array along the time-division multiplexing module 120. When the defect detection device 100 is operating normally, it advances at a constant speed in the oil pipeline. Each pipeline circumferential weld is pre-divided into eight segments, and each excitation module 130 is configured to detect one segment of each of the eight segments. That is, for each 360° circumferential direction of the circumferential weld, each excitation module 130 is configured to detect 45° of each pipeline circumferential weld. In this way, the location of the defect in the pipeline circumferential weld can be determined based on the excitation module 130 that acquires the induced voltage amplitude.

[0057] The following example illustrates the operation of the time-division multiplexing module 120. The time-division multiplexing module 120 selects the path for the multi-channel excitation coils so that the two AC sinusoidal signals (i.e., the fifth and sixth AC sinusoidal signals) generated by the excitation signal generator 110 can be used by multiple excitation modules 130. The output interface of the AC sinusoidal signal generated by the excitation signal generator 110 that meets the excitation intensity requirements and the detection signal output interface are respectively connected to the common signal input / output pin Z of the time-division multiplexing module 120. One end of the coil wires of all excitation modules 130 is connected to GND. In the case where the defect detection device 100 includes eight excitation modules 130, the other end of the wire of the first quadrature excitation unit 131 of each excitation module 130 is connected to an independent input / output interface X. 1a ,X 2a ,…,X 8a The other end of the wire of the second orthogonal excitation unit 132 of each excitation module 130 is connected to an independent input / output interface X. 1b ,X 2b ,…,X 8b Each excitation module 130's detection unit 133 (including the detection coil) is connected to an independent input / output interface Y1, Y2, ..., Y8 at one end. The control channel's common terminal Z is controlled via high / low level combinations of address pins A0, A1, A2, etc. 1A Z 1B Z2 and channel X 1a ,X 2a ,…,X 8a X 1b ,X 2b ,…,X 8b The conduction of Y1, Y2, ..., Y8 enables time-division eight-channel multiplexing of two AC sinusoidal signals, meaning that the two AC sinusoidal signals can be reused by eight excitation modules in a 130-fold time division. The pulse sequence is shown in Figure 6, and the channel selection logic combination is shown in Table 1.

[0058] Table 1

[0059] By using the logic combination shown in Table 1, the two AC sinusoidal signals can be reused by eight excitation modules 130 in a time-division manner through the time-division multiplexing module 120. It should be noted that the above working process of the time-division multiplexing module 120 is only an example.

[0060] In some embodiments, the signal acquisition module 140 also communicates with the time-division multiplexing module 120, and the signal acquisition module 140 is further configured to determine the identification information of the target excitation module for acquiring the induced voltage amplitude of the pipe circumferential weld to be detected, wherein the target excitation module is one of a plurality of excitation modules 130; and is configured to send the identification information of the target excitation module to the signal processing module 150, wherein the signal processing module 150 is configured to determine the defect location of the pipe circumferential weld to be detected based on the identification information of the target excitation module.

[0061] For example, the signal acquisition module 140 determines the detection time of the induced voltage amplitude of the pipe circumferential weld to be detected based on the pulse width modulation (PWM) wave input to the time-division multiplexing module 120, then determines the target excitation module for acquiring the induced voltage amplitude of the pipe circumferential weld to be detected based on the detection time, and then determines the defect location of the pipe circumferential weld to be detected based on the position of the target excitation module in the pipe.

[0062] In this embodiment, the AC sinusoidal signal input of multiple excitation modules 130 is realized through the time-division multiplexing module 120, which can reduce the power consumption of the excitation signal generator 110. Furthermore, by determining the target excitation module that detects the amplitude of the induced voltage, the defect location of the pipe circumferential weld to be detected can be determined, thereby improving the confidence of the defect detection result, reducing the defect detection time, and improving the defect detection efficiency.

[0063] The above examples of eight excitation modules 130 are for illustrative purposes only. The embodiments of this application may set more or fewer excitation modules 130 according to actual defect detection needs.

[0064] As described above, the device provided in this application sends an AC sinusoidal signal to the first orthogonal excitation unit 131 and the second orthogonal excitation unit 132 via the excitation signal generator 110. This causes the first excitation coil 1311 and the second excitation coil 1312, which are orthogonally arranged in the first orthogonal excitation unit 131, and the third excitation coil 1321 and the fourth excitation coil 132, which are orthogonally arranged in the second orthogonal excitation unit 132, to generate a composite alternating magnetic field. When the defect detection device 100 passes through the pipe circumferential weld, defects located at different positions and angles of the pipe circumferential weld can vertically cut the induced magnetic lines of force in the composite alternating magnetic field. By detecting the amplitude of the induced voltage generated by the vertical cutting, rapid and accurate detection of defects in the pipe circumferential weld at different positions and angles can be achieved, thereby improving detection efficiency and reducing detection costs.

[0065] In summary, the device provided in this application solves the problem of detecting defects in circumferential welds at different angles by detecting the amplitude of the induced voltage generated by multiple excitation coils, using a circumferentially symmetrical differential configuration of multiple excitation units, and sending different AC sinusoidal signals to each excitation unit. This achieves physical filtering of the detection signal at large lift-off points and full coverage detection of the rotating excitation magnetic field. This application effectively improves the sensitivity and reliability of defect detection, significantly reducing the false negative rate of pipeline circumferential weld defects. Specifically, by setting up a first orthogonal excitation unit 131 and a second orthogonal excitation unit 132, and performing inspection based on the composite alternating magnetic field generated by the first orthogonal excitation unit 131 and the second orthogonal excitation unit 132, the device can reduce the influence of lift-off signal noise on the detection signal. This improves the detection rate of multi-angle pipeline circumferential weld defects and enhances the ability to assess the failure risk of pipeline circumferential welds.

[0066] In some embodiments, the defect detection device 100 of this application can be used for in-pipe inspection. It enters the pipe with a carrier and performs a 360° scan of the circumferential weld seam using the circumferential array excitation module 130, identifying multi-angle defects using a composite alternating magnetic field. In other embodiments, the defect detection device 100 of this application can be used for out-of-pipe inspection. It fits against the outside of the pipe's circumferential weld seam, reduces lifting jitter with the help of an arc-shaped ceramic plate 170, and, in conjunction with a time-division multiplexing module 120, controls the excitation coil path to quickly locate defects.

[0067] In some embodiments, referring to FIG7, this application embodiment also provides a method for detecting defects in anti-lift-off pipe circumferential welds, applied to the above-mentioned defect detection device 100, the method comprising the following steps:

[0068] S1. The excitation signal generator outputs an AC sine wave signal to the time-division multiplexing module.

[0069] For example, the AC sinusoidal signal includes a fifth AC sinusoidal signal and a sixth AC sinusoidal signal, wherein the fifth AC sinusoidal signal and the sixth AC sinusoidal signal have opposite signal directions and the same amplitude; the amplitude A and angular frequency ω of the fifth AC sinusoidal signal and the sixth AC sinusoidal signal are determined according to the pipe material where the circumferential weld of the pipe to be detected is located.

[0070] S2. The time-division multiplexing module sends a first AC sinusoidal signal to the first excitation coil, a second AC sinusoidal signal to the second excitation coil, a third AC sinusoidal signal to the third excitation coil, and a fourth AC sinusoidal signal to the fourth excitation coil, in order to form a composite alternating magnetic field.

[0071] The composite alternating magnetic field includes a magnetic field formed by a first excitation coil, a second excitation coil, a third excitation coil, and a fourth excitation coil; wherein, the second AC sinusoidal signal is a signal obtained by shifting the phase of the first AC sinusoidal signal by 90°, the third AC sinusoidal signal is a signal with the opposite direction and the same amplitude as the first AC sinusoidal signal, and the fourth AC sinusoidal signal is a signal obtained by shifting the phase of the third AC sinusoidal signal by 90°.

[0072] S3. When the excitation module passes the circumferential weld of the pipe to be detected, the detection unit acquires the induced voltage amplitude of the circumferential weld of the pipe to be detected and sends the induced voltage amplitude to the signal acquisition module.

[0073] S4. The signal acquisition module determines the identification information of the circumferential weld of the pipeline to be inspected, and sends the induced voltage amplitude and identification information of the circumferential weld of the pipeline to be inspected to the signal processing module.

[0074] S5. The signal processing module determines the defect detection result of the circumferential weld of the pipeline to be detected based on the induced voltage amplitude and identification information. The defect detection result includes normal and abnormal.

[0075] For a description of the above method embodiments, please refer to the foregoing apparatus embodiments. Furthermore, explanations and descriptions of the beneficial effects of any of the above-provided methods for detecting defects in pipe circumferential welds can be found in the corresponding apparatus embodiments described above.

Claims

1. A device for detecting defects in circumferential welds of pipelines that resist lifting, comprising: The system includes an excitation signal generator, a time-division multiplexing module, at least one excitation module, a signal acquisition module, and a signal processing module. The excitation signal generator is connected to the time-division multiplexing module, the time-division multiplexing module is connected to the excitation module, the excitation module is connected to the signal acquisition module, and the signal acquisition module is connected to the signal processing module. The excitation module includes a first orthogonal excitation unit, a second orthogonal excitation unit, and a detection unit. The first orthogonal excitation unit and the second orthogonal excitation unit are both connected to the time-division multiplexing module. The first orthogonal excitation unit includes a first excitation coil and a second excitation coil arranged orthogonally to each other. The second orthogonal excitation unit includes a third excitation coil and a fourth excitation coil arranged orthogonally to each other. The detection unit is connected to the signal acquisition module. The excitation signal generator is configured to output an AC sinusoidal signal to the time-division multiplexing module; The time-division multiplexing module is configured to send a first AC sinusoidal signal to the first excitation coil, a second AC sinusoidal signal to the second excitation coil, a third AC sinusoidal signal to the third excitation coil, and a fourth AC sinusoidal signal to the fourth excitation coil, based on the AC sinusoidal signal, to form a composite alternating magnetic field. The composite alternating magnetic field includes the magnetic field formed by the first excitation coil, the second excitation coil, the third excitation coil, and the fourth excitation coil. The second AC sinusoidal signal is obtained by shifting the phase of the first AC sinusoidal signal by 90°. The third AC sinusoidal signal is a signal with the opposite direction and the same amplitude as the first AC sinusoidal signal. The fourth AC sinusoidal signal is obtained by shifting the phase of the third AC sinusoidal signal by 90°. The detection unit is configured to acquire the induced voltage amplitude of the circumferential weld of the pipe to be detected when the excitation module passes the circumferential weld of the pipe to be detected, and to send the induced voltage amplitude to the signal acquisition module. The signal acquisition module is configured to determine the identification information of the circumferential weld of the pipeline to be inspected, and to send the induced voltage amplitude and identification information of the circumferential weld of the pipeline to be inspected to the signal processing module. The signal processing module is configured to determine the defect detection result of the circumferential weld of the pipeline to be detected based on the induced voltage amplitude and identification information of the circumferential weld. The defect detection result includes normal and abnormal.

2. The apparatus according to claim 1, wherein, The device includes multiple excitation modules, which are arranged in a circumferential array along the time-division multiplexing module.

3. The apparatus according to claim 2, wherein, The signal acquisition module also communicates with the time-division multiplexing module. The signal acquisition module is further configured to determine the identification information of the target excitation module for acquiring the induced voltage amplitude of the circumferential weld of the pipeline to be inspected, wherein the target excitation module is one of the plurality of excitation modules; and is configured to send the identification information of the target excitation module to the signal processing module. The signal processing module is configured to determine the defect location of the circumferential weld of the pipeline to be inspected based on the identification information of the target excitation module.

4. The apparatus according to claim 1, wherein, The first excitation coil, the second excitation coil, the third excitation coil, and the fourth excitation coil are rectangular coils, and the detection unit includes a circular coil.

5. The apparatus according to claim 1, wherein, The excitation signal generator includes a sine wave generator and a phase shifter; the excitation signal generator is configured to output a fifth AC sine wave signal and a sixth AC sine wave signal to the time-division multiplexing module, wherein the fifth AC sine wave signal and the sixth AC sine wave signal have opposite signal directions and the same amplitude; The time-division multiplexing module is configured to: obtain the first AC sine wave signal and the second AC sine wave signal based on the fifth AC sine wave signal, obtain the third AC sine wave signal and the fourth AC sine wave signal based on the sixth AC sine wave signal, send the first AC sine wave signal to the first excitation coil, send the second AC sine wave signal to the second excitation coil, send the third AC sine wave signal to the third excitation coil, and send the fourth AC sine wave signal to the fourth excitation coil.

6. The apparatus according to claim 1, wherein, The signal processing module is configured to determine that the defect detection result of the pipe circumferential weld is abnormal when the amplitude of the induced voltage of the weld to be detected is greater than a preset threshold.

7. The apparatus according to claim 1, wherein, The signal processing module is configured to determine that the defect detection result of the pipe circumferential weld is normal when the amplitude of the induced voltage of the weld to be detected is less than or equal to a preset threshold.

8. The device according to claim 1 further includes a protective housing, wherein the excitation signal generator, the time-division multiplexing module, the excitation module, the signal acquisition module, and the signal processing module are all disposed inside the protective housing.

9. The device according to claim 8 further includes an arc-shaped ceramic sheet disposed at the bottom of the protective shell.

10. A method for detecting defects in circumferential welds of pipelines resistant to lift-off, applied to a device for detecting defects in circumferential welds of pipelines resistant to lift-off, the device comprising an excitation signal generator, a time-division multiplexing module, at least one excitation module, a signal acquisition module, and a signal processing module; the excitation signal generator is connected to the time-division multiplexing module, the time-division multiplexing module is connected to the excitation module, the excitation module is connected to the signal acquisition module, and the signal acquisition module is connected to the signal processing module; The excitation module includes a first orthogonal excitation unit, a second orthogonal excitation unit, and a detection unit. The first orthogonal excitation unit and the second orthogonal excitation unit are both connected to the time-division multiplexing module. The first orthogonal excitation unit includes a first excitation coil and a second excitation coil arranged orthogonally to each other. The second orthogonal excitation unit includes a third excitation coil and a fourth excitation coil arranged orthogonally to each other. The detection unit is connected to the signal acquisition module. The method includes: The excitation signal generator outputs an AC sinusoidal signal to the time-division multiplexing module; The time-division multiplexing module sends a first AC sinusoidal signal to the first excitation coil, a second AC sinusoidal signal to the second excitation coil, a third AC sinusoidal signal to the third excitation coil, and a fourth AC sinusoidal signal to the fourth excitation coil, based on the AC sinusoidal signal, to form a composite alternating magnetic field. The composite alternating magnetic field includes the magnetic field formed by the first excitation coil, the second excitation coil, the third excitation coil, and the fourth excitation coil. The second AC sinusoidal signal is obtained by shifting the phase of the first AC sinusoidal signal by 90°. The third AC sinusoidal signal is a signal with the opposite direction and the same amplitude as the first AC sinusoidal signal. The fourth AC sinusoidal signal is obtained by shifting the phase of the third AC sinusoidal signal by 90°. When the excitation module passes the circumferential weld of the pipe to be detected, the detection unit acquires the induced voltage amplitude of the circumferential weld of the pipe to be detected, and sends the induced voltage amplitude to the signal acquisition module. The signal acquisition module determines the identification information of the circumferential weld of the pipeline to be detected, and sends the induced voltage amplitude and identification information of the circumferential weld of the pipeline to be detected to the signal processing module; The signal processing module determines the defect detection result of the circumferential weld of the pipeline to be detected based on the induced voltage amplitude and identification information of the circumferential weld. The defect detection result includes normal and abnormal.

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