An insertable electromagnetic ultrasonic guided wave phased array probe and detection system for pipelines

Abstract

The present invention provides an insertable electromagnetic ultrasonic guided wave phased array probe and detection system for pipelines, which are used for long-distance and large-scale detection of defects in small-diameter metal bends. The overall structure of the probe is an elongated cylindrical shape, and is composed of a toroidal transceiver coil array, an annular magnet, an annular magnetic core, an axial fastener, a centering cone block, and a signal connection line; its supporting detection system is composed of a probe, a multi-channel high-voltage pulse excitation module, a multi-channel preamplifier module, a multi-channel timing control module, a multi-channel signal acquisition card, and a control computer. During detection, the probe is inserted from the open end of the bend. The probe does not need to contact the pipe wall. The excitation and reception of ultrasonic guided waves are achieved through electromagnetic induction, and the enhancement of guided wave signals is achieved through delayed triggering and delayed superposition of a multi-channel array. The probe and detection system of the present invention can significantly enhance the strength of ultrasonic guided wave signals, while reducing interference from other modes and frequency dispersion, greatly improving the detection distance and defect detection capability in the bend.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline defect detection, and specifically to an insertable electromagnetic ultrasonic guided wave phased array probe for pipelines, a matching electromagnetic ultrasonic guided wave phased array detection system, and a detection method. The probe can be used for long-distance and large-range defect detection in metal small-diameter curved pipes with complex curved structures and densely arranged structures. Background Art

[0002] Small-diameter curved metal pipes, such as steam generator heat exchange tubes, are core components of nuclear power plants. Operating in harsh environments for extended periods, they are subject to erosion by high-temperature gases and steam, thermal stress, and strong radiation, making them susceptible to cracks and corrosion defects. Due to their dense arrangement, complex piping routes, and the presence of numerous curved and spiral sections, there is currently no efficient and feasible nondestructive testing method for locating volumetric defects. Ultrasonic guided wave testing, an emerging nondestructive testing technology, leverages the ability of ultrasonic guided waves to propagate long distances along the pipeline axis. Single-point testing with a probe allows for full-range inspection of pipelines over long distances. Ultrasonic guided wave technology not only offers the advantages of high detection efficiency and a wide detection range, but also allows for the detection of curved pipes and exhibits strong geometric adaptability.

[0003] Currently, piezoelectric contact probes are commonly used for pipeline guided wave detection. These probes require the application of a coupling agent to the specimen surface, ensuring effective coupling between the probe and the specimen surface. These probes place high demands on the surface of the test object, and their installation and layout are complex. Electromagnetic ultrasonic probes are non-contact, require no coupling agent, have low requirements on the specimen surface, are easy to install, and require less equipment complexity and operational difficulty for automated detection. Ultrasonic guided wave detection methods based on electromagnetic ultrasonic probes have promising application prospects for defect detection in complex pipelines. However, electromagnetic ultrasonic probes suffer from a low signal-to-noise ratio, and the attenuation and dispersion of ultrasonic guided waves in long bends cause severe wave packet diffusion, limiting the effective detection distance of the probe in bends. Therefore, a portable probe with long-distance detection capabilities for bends, as well as a supporting detection system and method, has been proposed. This is of great significance for volumetric defect detection in small-diameter metallic bends, such as steam generator heat exchange tubes. Summary of the Invention

[0004] The present invention aims to provide an insertable electromagnetic ultrasonic guided wave phased array probe and detection system for long-distance detection of small-diameter curved metal pipes, which are non-contact, easy to deploy, have good detection accessibility, long detection distance, high detection signal-to-noise ratio and sensitivity. The probe is inserted into the opening at the end of the curved pipe, and the proposed detection system can be used to realize long-distance ultrasonic guided wave phased array detection of the curved pipe.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] An insertable electromagnetic ultrasonic guided wave phased array probe for a pipeline comprises a toroidal transceiver coil 1, an annular magnet 2, an annular magnetic core 3, an axial fastener 4, a centering tapered block 5, and a signal connecting line 6. The annular magnet 2 and the annular magnetic core 3 are alternately arranged in the axial direction, and a plurality of toroidal transceiver coils 1 are tightly wound around the outside of the annular magnetic core 3 to form an annular transceiver coil array. The axial fastener 4 constrains and reinforces the annular magnet 2 and the annular magnetic core 3. The centering tapered block 5 is arranged at the end of the axial fastener 4. The signal connecting line 6 is led out from the toroidal transceiver coil 1, passes through the central through hole of the axial fastener 4, and converges into a cable.

[0007] The annular magnet 2 is a permanent magnet or an electromagnet coil, and the magnetic pole directions of adjacent magnets are arranged in pairs, the same or opposite, respectively, to provide an axial or radial magnetic field along the pipeline for the annular transceiver coil 1; a single annular transceiver coil 1 and its adjacent annular magnet 2 constitute a probe array element and are arranged in an axial array. The center spacing d of adjacent annular transceiver coils satisfies the relationship Δt with the relative delay Δt of the trigger delay sequence of adjacent channels and the axial guided wave group velocity c: Δt = d / c.

[0008] A plug-in electromagnetic ultrasonic guided wave phased array detection system for pipelines includes a multi-channel high-voltage train pulse excitation module 7, a multi-channel preamplifier module 8, a multi-channel timing control module 9, a multi-channel signal acquisition card 10, a control computer 11, and the plug-in electromagnetic ultrasonic guided wave phased array probe. The annular transceiver coil array of the plug-in electromagnetic ultrasonic guided wave phased array probe is connected one-to-one with each channel in the multi-channel high-voltage train pulse excitation module 7 and the multi-channel preamplifier module 8. The multi-channel timing control module 9 triggers the connection to the multi-channel high-voltage train pulse excitation module 7. The input end of the multi-channel signal acquisition card 10 is connected one-to-one with each channel of the multi-channel preamplifier module 8. The output end of the multi-channel signal acquisition card 10 is connected to the input end of the control computer 11. The output end of the control computer 11 is connected to the multi-channel high-voltage train pulse excitation module 7, the multi-channel preamplifier module 8, and the multi-channel timing control module 9.

[0009] During the inspection, the insertable electromagnetic ultrasonic guided wave phased array probe is first inserted into the opening at the end of the inspected curved pipe until all the annular transceiver coils 1 of the probe are completely placed in the curved pipe; the multi-channel timing control module 9 triggers the multi-channel high-voltage train pulse excitation module 7 in sequence according to the movement sequence to output high-frequency pulse current to each array element of the annular transceiver coil array, and induces eddy current or dynamic magnetic field 14 in the pipe wall in turn, and interacts with the bias magnetic field 13 generated by the annular magnet 2 to generate electromagnetic force, thereby exciting the ultrasonic guided wave pulse sequence in a certain sequence in the pipe wall below each array element of the annular transceiver coil array, so that the ultrasonic guided wave pulse sequence excited by each array element produces the same phase superposition, thereby forming The enhanced ultrasonic guided wave pulse is generated while suppressing the generation of other guided wave modes with different wave velocities. When the enhanced ultrasonic guided wave propagates in the pipeline and encounters defects, the enhanced pulse echo generated reacts with the bias magnetic field 13 to form an induced electromagnetic field, which is received in sequence by each element of the circular transceiver coil array, amplified by the multi-channel preamplifier module 8 and converted into a digital signal by the multi-channel signal acquisition card 10, and transmitted to the control computer 11 for acquisition. Finally, the obtained multi-channel guided wave detection signal is delayed and superimposed to form an electromagnetic ultrasonic guided wave phased array detection enhancement signal. While enhancing the detection signal, the dispersion effect of the guided wave and the interference of other guided wave mode signals with different wave velocities are further suppressed.

[0010] The multi-channel high-voltage train pulse excitation module 7 outputs a high-voltage kHz frequency square wave or sine wave train pulse; the multi-channel timing control module 9 and the multi-channel high-voltage train pulse excitation module 7 have the same number of channels, and the multi-channel preamplifier module 8 and the multi-channel signal acquisition card 10 have the same number of channels.

[0011] The connection mode between each probe array element and the multi-channel high-voltage train pulse excitation module 7 and the multi-channel preamplifier module 8 adopts a mode in which some array elements are connected to excitation and other array elements are connected to reception, or each array element is simultaneously excited and received. The latter mode requires the addition of a multi-channel duplexer in the detection system to realize the connection and merging of excitation and reception. When the detection system is connected to the continuous loop-shaped transceiver coil 1 array element, the final superposition signal Sig(t) and the i-th channel received signal s i The delayed superposition processing of (t) satisfies the relationship:

[0012]

[0013] This invention proposes a novel electromagnetic ultrasonic guided wave phased array probe, its supporting detection system, and its detection method for long-distance defect detection in small-diameter curved metal pipes. The probe only needs to be inserted through the opening at the end of the curved pipe to detect defects over long distances. This invention combines the advantages of ultrasonic guided waves, electromagnetic ultrasonic probes, and ultrasonic phased array testing. The probe offers the advantages of non-contact, easy deployment within the pipe, and excellent detection accessibility. The detection method, through focusing of the ultrasonic phased array, significantly increases the amplitude of the guided wave detection signal, thereby improving the detection range, signal-to-noise ratio, and detection sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is an axial cross-sectional view of the structure of an insertable electromagnetic ultrasonic guided wave phased array probe for a pipeline of the present invention and a schematic diagram of the phased array detection system connected thereto.

[0015] Figure 2 Schematic diagram of the phased array principle of the probe waveguide excitation and detection echo signal of the present invention.

[0016] Figure 3 This is a schematic diagram of the arrangement of the probe of the present invention in a pipeline. DETAILED DESCRIPTION

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1As shown, the present invention proposes an insertable electromagnetic ultrasonic guided wave phased array probe for long-distance inspection of small-diameter curved metallic pipes. The probe comprises a circular transceiver coil 1, a circular magnet 2, a circular magnetic core 3, an axial fastener 4, a centering cone 5, and a signal connection line 6. The circular magnet 2 and the circular magnetic core 3 are arranged alternately in the axial direction. Multiple circular transceiver coils 1 are tightly wound around the outer sides of the circular magnetic core 3 to form a circular transceiver coil array. The axial fastener 4 constrains and reinforces the circular magnet 2 and the circular magnetic core 3. The centering cone 5 is positioned at the end of the axial fastener 4. The signal connection line 6 extends from the circular transceiver coil 1 and passes through the center hole of the axial fastener 4. The probe's circular magnet 2 is magnetized along its axial direction, with the poles of adjacent magnets either aligned or opposite. The Lorentz force mechanism employs the opposite polarity of adjacent magnets to generate a radial bias magnetic field, while the magnetostrictive mechanism employs the same polarity to generate an axial bias magnetic field. The probe's detection principle is as follows: When powered on, the annular transceiver coils 1 in each unit of the array induce axisymmetrically distributed eddy current fields 14 and dynamic magnetic fields 15 near the inner surface of the pipe. These interact with the bias magnetic field 13 provided by the annular magnet 2. Based on the Lorentz force or magnetostrictive mechanism, these forces are generated near the inner surface of the pipe, which excite ultrasonic waves. The echoes are then received by the coils through the reverse effect. The annular transceiver coil array is evenly spaced along the probe's axis. The center-to-center spacing d between adjacent coils, the relative delay Δt between adjacent channels, and the axial ultrasonic guided wave group velocity c satisfy the relationship: Δt = d / c.

[0019] Insert the insertable electromagnetic ultrasonic guided wave phased array probe through the opening at the end of the inspected curved pipe until all the probe's annular transceiver coils 1 are completely placed inside the curved pipe. Each array element of the annular transceiver coil array is simultaneously connected to each channel of the multi-channel high-voltage train pulse excitation module 7 and the multi-channel preamplifier module 8. During operation, the multi-channel timing control module 9 sequentially triggers the multi-channel high-voltage train pulse excitation module 7 to output high-frequency pulse current to each array element of the annular transceiver coil array according to the movement timing, inducing an axisymmetrically distributed eddy current field 14 or dynamic magnetic field 14 on the pipe wall. These interact with the bias magnetic field 13 generated by the annular magnet 2 to generate electromagnetic force, thereby exciting an ultrasonic guided wave pulse sequence in a certain timing sequence in the pipe wall below each array element of the annular transceiver coil array. This causes the ultrasonic guided wave pulse sequence excited by each array element to produce an in-phase superposition, thereby forming an enhanced ultrasonic guided wave pulse, while suppressing the generation of other guided wave modes with different wave speeds. When the enhanced ultrasonic guided wave propagates in the pipeline and encounters defects, the enhanced pulse echo generated interacts with the bias magnetic field 13 to form an induced electromagnetic field, which is received in sequence by each array element of the circular transceiver coil array 1, amplified by the multi-channel preamplifier module 8 and converted into a digital signal by the multi-channel signal acquisition card 10, and transmitted to the control computer 11 for acquisition. Finally, the obtained multi-channel guided wave detection signal is delayed and superimposed to form an electromagnetic ultrasonic guided wave phased array detection enhancement signal. While enhancing the detection signal, the dispersion effect of the guided wave and the interference of other guided wave mode signals with different wave speeds are further suppressed.

[0020] The following combination Figure 2 、 Figure 3 The probe and detection system are further described in detail in the following specific embodiments.

[0021] An insertable electromagnetic ultrasonic guided wave phased array probe, detection system, and method for pipelines, specifically comprising the following steps:

[0022] Step 1: If Figure 3 As shown, an insertable electromagnetic ultrasonic guided wave phased array probe 19 is placed into the pipe end opening until all of the probe's circumferential transceiver coils 1 are completely positioned within the curved pipe. When the excited ultrasonic guided wave 12 encounters a defect 18, it generates a defect echo 17, which is received by each array element 16 in the probe. By detecting these defect echoes, defects in the pipeline can be located and quantitatively detected.

[0023] Step 2: The control computer 11 instructs the multi-channel timing control module 9 to output a trigger signal with a set relative delay, triggering the multi-channel high-voltage pulse train excitation module 7 to output a high-frequency, high-intensity pulse train current that flows into the annular transceiver coil array. The annular transceiver coils 1 in each unit of the array excite ultrasonic guided waves 12 propagating along the pipeline's axial direction based on the Lorentz force or magnetostriction mechanism. The reflected defect echo 17 is received by the probe based on the inverse effects of the Lorentz force and magnetostriction mechanism.

[0024] Step 3: If Figure 2 As shown, the ultrasonic guided wave 12 excited by the inner wall of the pipe propagates axially. While ensuring that the delay satisfies Δt = d / c, the ultrasonic guided waves 12 excited by each array element 16 can be superimposed at the same axial position, thereby enhancing the ultrasonic guided wave signal to form an enhanced ultrasonic guided wave pulse. The time interval between the echo 17 reaching each array element 16 also satisfies Δt = d / c. The defect echo 17 is converted into an induced voltage signal by the probe, amplified by the multi-channel preamplifier module 8, and then passed to the multi-channel signal acquisition card 10 for conversion into a digital signal. This signal is then transmitted to the control computer 11 for delay superposition processing, resulting in the superposition signal Sig(t) and the i-th channel received signal s. i The delayed superposition processing of (t) satisfies the relationship:

[0025]

Claims

1. An insertable electromagnetic ultrasonic guided wave phased array inspection system for pipelines, characterized by: The invention comprises a multi-channel high-voltage pulse train excitation module (7), a multi-channel preamplifier module (8), a multi-channel timing control module (9), a multi-channel signal acquisition card (10), a control computer (11) and an insertable electromagnetic ultrasonic guided wave phased array probe for a pipeline; the insertable electromagnetic ultrasonic guided wave phased array probe for a pipeline comprises a circumferential transceiver coil (1), a circumferential magnet (2), a circumferential magnetic core (3), an axial fastener (4), a centering conical block (5) and a signal connecting line (6); the circumferential magnet (2) and the circumferential magnetic core (3) are alternately arranged in the axial direction, a plurality of circumferential transceiver coils (1) are tightly wound around the outer side of the circumferential magnetic core (3) to form a circumferential transceiver coil array, the axial fastener (4) constrains and reinforces the circumferential magnet (2) and the circumferential magnetic core (3), and the centering conical block (5) is arranged in the axial direction. At the end of the fastener (4), a signal connection line (6) is led out from the annular transceiver coil (1) and passes through the central through hole of the axial fastener (4) and is gathered into a cable; the annular transceiver coil array of the plug-in electromagnetic ultrasonic guided wave phased array probe is connected one-to-one with each channel in the multi-channel high-voltage string pulse excitation module (7) and the multi-channel preamplifier module (8); the multi-channel timing control module (9) triggers the connection to the multi-channel high-voltage string pulse excitation module (7); the input end of the multi-channel signal acquisition card (10) is connected one-to-one with each channel of the multi-channel preamplifier module (8); the output end of the multi-channel signal acquisition card (10) is connected to the input end of the control computer (11); the output end of the control computer (11) is connected to the multi-channel high-voltage string pulse excitation module (7), the multi-channel preamplifier module (8) and the multi-channel timing control module (9); During the inspection, the insertion type electromagnetic ultrasonic guided wave phased array probe is first inserted into the opening at the end of the inspected curved pipe until all the annular transceiver coils (1) of the probe are completely placed in the curved pipe; the multi-channel timing control module (9) triggers the multi-channel high-voltage train pulse excitation module (7) to output high-frequency pulse current to each array element of the annular transceiver coil array in sequence according to the moving timing, and sequentially induces eddy current or dynamic magnetic field (14) on the pipe wall, and interacts with the bias magnetic field (13) generated by the annular magnet (2) to generate electromagnetic force, thereby exciting an ultrasonic guided wave pulse sequence in each array element of the annular transceiver coil array according to a certain timing, and the ultrasonic guided wave pulse sequence excited by each array element generates the same phase. The enhanced ultrasonic guided wave pulse is superimposed to form an enhanced ultrasonic guided wave pulse, while suppressing the generation of other guided wave modes with different wave speeds; when the enhanced ultrasonic guided wave propagates in the pipeline and encounters defects, the enhanced pulse echo generated interacts with the bias magnetic field (13) to form an induced electromagnetic field, which is received in sequence by each element of the circular transceiver coil array, amplified by a multi-channel preamplifier module (8), and converted into a digital signal by a multi-channel signal acquisition card (10), and transmitted to a control computer (11) for acquisition. Finally, the obtained multi-channel guided wave detection signal is delayed and superimposed to form an electromagnetic ultrasonic guided wave phased array detection enhanced signal, thereby suppressing the dispersion effect of the guided wave and the interference of other guided wave mode signals with different wave speeds.

2. The insertable electromagnetic ultrasonic guided wave phased array detection system for pipelines according to claim 1 is characterized in that: The annular magnet (2) is a permanent magnet or an electromagnet coil, and the magnetic pole directions of adjacent magnets are arranged in pairs, the same or opposite to each other, respectively, to provide an axial or radial magnetic field along the pipeline for the annular transceiver coil (1); a single annular transceiver coil (1) and its adjacent annular magnet (2) form a probe array element and are arranged into an axial array, and the center spacing d of adjacent annular transceiver coils and the relative delay Δt of the adjacent channel trigger delay sequence and the axial guided wave group velocity c satisfy the relationship: Δt=d / c.

3. The insertable electromagnetic ultrasonic guided wave phased array detection system for pipelines according to claim 1 is characterized by: The multi-channel high-voltage train pulse excitation module (7) outputs high-voltage square wave or sine wave train pulses at a kHz frequency; the multi-channel timing control module (9) and the multi-channel high-voltage train pulse excitation module (7) have the same number of channels, and the multi-channel preamplifier module (8) and the multi-channel signal acquisition card (10) have the same number of channels.

4. The insertable electromagnetic ultrasonic guided wave phased array detection system for pipelines according to claim 1, characterized in that: The connection mode of each array element of the probe with the multi-channel high-voltage pulse train excitation module (7) and the multi-channel preamplifier module (8) adopts a mode in which a part of the array elements are connected to the excitation and the other part of the array elements are connected to the reception, or a mode in which each array element is simultaneously excited and received. The latter mode requires a multi-channel duplexer to be added to the detection system to realize the connection and merging of the excitation and reception. When the detection system is connected to the array element of the continuous circular transceiver coil (1), the final superposition signal Sig(t) and the i-th channel reception signal s i The delayed superposition processing of (t) satisfies the relationship:

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