Magnetostrictive guided wave transducer and pipe inspection system for pipe inspection

Abstract

The application discloses a magnetostrictive guided wave transducer and a pipeline detection system, and relates to the technical field of pipeline detection. The magnetostrictive guided wave transducer comprises at least one vibrating piece and a transducing assembly capable of generating a first vibration signal and receiving a second vibration signal returned by a pipeline, the transducing assembly is connected with the vibrating piece, and the vibrating piece is in contact with the pipeline; the transducing assembly transmits the generated first vibration signal to the pipeline through the vibrating piece; and the second vibration signal returned by a defect position of the pipeline is transmitted back to the transducing assembly through the vibrating piece. The application solves the technical problem that the existing guided wave transducer and super-magnetostrictive material have poor defect detection effect on the pipeline.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline detection, and in particular to a magnetostrictive guided wave transducer for pipeline detection and a pipeline detection system. Background Art

[0002] Pipeline transportation is the primary mode of natural gas transportation. With the rapid growth in natural gas demand, the construction of corresponding pipeline network facilities has also developed rapidly. Currently, most long pipelines are buried underground, traversing vast areas with complex terrain. The corrosion characteristics of soil vary across different terrains. Coupled with factors such as stray currents and corrosion from the transported medium, pipelines are susceptible to external corrosion, which reduces their lifespan and safety. Accidents involving long pipelines are extremely dangerous. To avoid major safety incidents and eliminate potential safety hazards, the evaluation and management of pipeline safety, as well as the detection and even monitoring of pipeline health, have received widespread attention. To ensure the normal use of pipelines and their safe, reliable, and efficient operation, regular inspections for defects such as cracks, fissures, breakages, corrosion, and rust are essential.

[0003] Magnetostrictive guided wave testing is a nondestructive testing technology capable of long-distance and large-scale testing. It can detect locations difficult to reach with existing non-contact testing methods, and has attracted widespread attention in the field of nondestructive testing of workpieces such as pipelines and railroad tracks. The low attenuation and long propagation distance of ultrasonic guided waves make ultrasonic guided wave testing technology highly efficient, and it has the ability to conduct real-time online testing and monitor the internal conditions of workpieces. The guided wave transducer is used to generate and receive ultrasonic guided waves and is the core component of ultrasonic guided wave testing. Magnetostrictive guided wave transducers are based on the magnetostrictive effect and the inverse magnetostrictive effect to achieve the mutual conversion between electromagnetic energy and mechanical energy. The electromechanical conversion coefficient of the magnetostrictive guided wave transducer determines the excitation power and receiving efficiency of the transducer.

[0004] Currently, the magnetostrictive material commonly used in guided wave detection systems is a thin strip made by rolling nickel or FeCoV. This material has a low magnetostriction coefficient, resulting in low conversion efficiency in the guided wave transducers produced from this material. This leads to high power requirements at the excitation end and low signal strength at the receiving end, limiting the detection range of guided wave detection. Although ultrasonic guided wave transducers and giant magnetostrictive materials have been applied to pipeline inspection, the inherent drawbacks of giant magnetostrictive materials, such as poor processing and mechanical properties, significantly shorten their service life and make them susceptible to wear and failure during use. Furthermore, the low resistivity of giant magnetostrictive materials leads to significant eddy current effects in high-frequency magnetic fields, which can affect detection effectiveness.

[0005] Currently, there is no effective solution to the problem that existing guided wave transducers and giant magnetostrictive materials used in related technologies have poor performance in pipeline defect detection.

[0006] Therefore, the inventors, relying on their many years of experience and practice in related industries, have proposed a magnetostrictive guided wave transducer and a pipeline detection system for pipeline detection to overcome the shortcomings of the prior art. Summary of the Invention

[0007] The purpose of the present invention is to provide a magnetostrictive guided wave transducer and pipeline inspection system for pipeline inspection, which can perform long-distance and large-scale non-contact non-destructive inspection of defects such as cracks, fissures, breakage, corrosion and rust in pipelines, with high detection accuracy and long service life.

[0008] Another object of the present invention is to provide a magnetostrictive guided wave transducer and pipeline inspection system for pipeline inspection. Multiple magnetostrictive guided wave transducers can be arranged in an array along the circumference of the pipeline. They are used for inspecting large-sized pipelines (pipelines with a diameter greater than or equal to 1 meter). Ultrasonic guided waves are excited in large-sized pipelines and echoes are received, thereby achieving the purpose of large-sized pipeline inspection.

[0009] The purpose of the present invention can be achieved by adopting the following technical solutions:

[0010] The present invention provides a magnetostrictive guided wave transducer for pipeline detection, comprising at least one vibrating element and a transducer assembly capable of generating a first vibration signal and receiving a second vibration signal returned by the pipeline, wherein the transducer assembly is connected to the vibrating element, and the vibrating element is in contact with the pipeline;

[0011] The transducer assembly transmits the generated first vibration signal to the pipeline via the vibrating element;

[0012] The second vibration signal returned by the defective position of the pipeline is transmitted back to the energy conversion component through the vibration element.

[0013] In a preferred embodiment of the present invention, the transducer component is connected to a connector that can receive and send electromagnetic signals. The transducer component converts the first electrical signal transmitted by the connector into the first vibration signal and transmits it to the pipeline, and the transducer component converts the received second vibration signal into a second electrical signal for external output.

[0014] In a preferred embodiment of the present invention, the transducer assembly includes a magnetostrictive element, an induction coil group and a permanent magnet, the induction coil group is arranged on the magnetostrictive element, the permanent magnet is arranged on the vibrating member, and the magnetostrictive element is connected to the vibrating member through the permanent magnet.

[0015] In a preferred embodiment of the present invention, the vibrating member includes a first vibrating component and a second vibrating component. The second vibrating component has an interior defining an accommodation space, the permanent magnet being disposed within the accommodation space. The second vibrating component is provided with a mounting hole communicating with the accommodation space. An end portion of the magnetostrictive element extends through the mounting hole into the accommodation space and is connected to the permanent magnet. The second vibrating component is connected to one end face of the first vibrating component, and the other, opposite end face of the first vibrating component is in contact with the surface of the pipe.

[0016] In a preferred embodiment of the present invention, a limiting groove is provided in the accommodating space, and the permanent magnet is fixed in the limiting groove.

[0017] In a preferred embodiment of the present invention, there are two vibrating members, the two vibrating members are arranged at an interval, the magnetostrictive element is a columnar structure, and the two ends of the magnetostrictive element respectively extend into the accommodating spaces corresponding to the two vibrating members.

[0018] In a preferred embodiment of the present invention, the magnetostrictive guided wave transducer for pipeline detection further includes a housing, one side of the housing is open, the two vibrating members and the transducer assembly are both disposed within the housing, and the first vibrating member on the two vibrating members extends from the open position to the outside of the housing and fits against the surface of the pipeline; a reed is sandwiched between at least one of the vibrating members and the inner wall of the housing.

[0019] In a preferred embodiment of the present invention, one of the vibrating elements, the energy conversion assembly, another of the vibrating elements and the reed are sequentially compressed and arranged in the housing from one inner wall to the other opposite inner wall.

[0020] In a preferred embodiment of the present invention, a closed magnetic circuit is formed among the vibrating member, the permanent magnet, the housing and the magnetostrictive element.

[0021] In a preferred embodiment of the present invention, the shell includes a shell body, a side plate and a cover plate, the cover plate is located at a position opposite to the opening, and the two ends of the cover plate are respectively connected to the shell body and the side plate, so as to enclose a space for accommodating the vibrator and the transducer assembly between the shell body, the side plate and the cover plate; the reed is clamped between the vibrator and the side plate.

[0022] In a preferred embodiment of the present invention, a first through hole is formed on the cover plate, and the connector extends to the outside through the first through hole;

[0023] At least two second through holes are provided on the cover plate, and first bolts are provided in the second through holes. The screw ends of the first bolts extend into the housing and are respectively connected to the corresponding vibrating members.

[0024] In a preferred embodiment of the present invention, the induction coil assembly includes multiple induction coil segments of the same length, wherein adjacent induction coil segments are wound in opposite directions on the magnetostrictive element, and the length of each induction coil segment is equal to half the wavelength of the guided wave in the first vibration signal generated by the magnetostrictive element.

[0025] In a preferred embodiment of the present invention, at least three layers of induction coil groups are wound on the magnetostrictive element from the inside, and the number of induction coils in each induction coil group is three.

[0026] In a preferred embodiment of the present invention, the magnetostrictive element has a columnar structure, the resonant frequency of the magnetostrictive element is equal to the frequency at which the magnetostrictive element excites the guided wave, and the length of the magnetostrictive element satisfies the following formula:

[0027]

[0028] Where l is the length of the magnetostrictive element; f is the resonant frequency; E 33 is the Young's modulus of the magnetostrictive element along the vibration direction; ρ is the density along the vibration direction.

[0029] In a preferred embodiment of the present invention, the magnetostrictive element is a composite material, which includes a terbium-dysprosium-iron alloy strip, an adhesive, a coupling agent, a curing agent and a defoaming agent, wherein the terbium-dysprosium-iron alloy strip is 30 to 70 parts, the thickness of the terbium-dysprosium-iron alloy strip is 45 μm to 1000 μm, the width of the terbium-dysprosium-iron alloy strip is 1.0 mm to 20.0 mm, the adhesive is 20 to 30 parts, the coupling agent is 0.3 to 0.7 parts, and the curing agent and the defoaming agent are 0.2 to 0.3 parts in total.

[0030] In a preferred embodiment of the present invention, the chemical formula of the terbium-dysprosium-iron alloy strip is Tb x Dy 1-x Fe y ; Among them, 0.27≤x≤0.4, 1.8≤y≤2.

[0031] In a preferred embodiment of the present invention, the chemical formula of the terbium-dysprosium-iron alloy strip is Tb 0.3 Dy 0.7 Fe2, the preparation method of the magnetostrictive element comprises the following steps:

[0032] Step S1: Smelting to form Tb0.3 Dy 0.7 Fe2 alloy ingot;

[0033] Step S2: Tb 0.3 Dy 0.7 The Fe2 alloy ingot is heated until it melts;

[0034] Step S3: melt Tb 0.3 Dy 0.7 Fe2 liquid alloy is sprayed onto a copper roller with a rotating speed to obtain Tb 0.3 Dy 0.7 Fe2 alloy strip;

[0035] Step S4: using an ethanol solution mixed with polydimethylsiloxane to 0.3 Dy 0.7 The surface of the Fe2 alloy strip is treated;

[0036] Step S5: Tb 0.3 Dy 0.7 The Fe2 alloy strip, the adhesive, the coupling agent, the curing agent and the defoaming agent are mixed to form a first premixture;

[0037] Step S6: transferring the first premixture into a mold cavity of a preset shape, and performing a degassing treatment on the first premixture under a vacuum environment;

[0038] Step S7: curing and molding the first premixture in the mold cavity to obtain the magnetostrictive element.

[0039] In a preferred embodiment of the present invention, the chemical formula of the terbium-dysprosium-iron alloy strip is Tb 0.3 Dy 0.7 Fe2, the preparation method of the magnetostrictive element comprises the following steps:

[0040] Step S1': Smelting to form Tb 0.3 Dy 0.7 Fe2 alloy ingot;

[0041] Step S2': Tb 0.3 Dy 0.7 The Fe2 alloy ingots were crushed and sieved to obtain Tb 0.3 Dy 0.7 Fe2 alloy particles;

[0042] Step S3': Tb 0.3 Dy 0.7 Fe2 alloy particles were added into an ethanol solution mixed with polydimethylsiloxane, and the Tb 0.3 Dy 0.7The surface of the Fe2 alloy particles is treated;

[0043] Step S4': Tb 0.3 Dy 0.7 The Fe2 alloy particles, the binder, the coupling agent, the curing agent and the defoaming agent are mixed to form a second premixture;

[0044] Step S5': transferring the second premixture into a mold cavity of a preset shape, and performing a degassing treatment on the second premixture under a vacuum environment;

[0045] Step S6 ′: curing and molding the second premixture in the mold cavity to obtain the magnetostrictive element.

[0046] The present invention provides a pipeline detection system, comprising a plurality of the aforementioned magnetostrictive guided wave transducers for pipeline detection, wherein each of the magnetostrictive guided wave transducers for pipeline detection is arranged on the outer wall of the pipeline along the circumference of the pipeline, and a vibrating element in each of the magnetostrictive guided wave transducers for pipeline detection is in contact with the outer wall of the pipeline.

[0047] In a preferred embodiment of the present invention, the pipeline detection system further includes an ultrasonic guided wave detection device, and the induction coil groups in each magnetostrictive guided wave transducer for pipeline detection are connected in series through corresponding connectors and then connected to the ultrasonic guided wave detection device.

[0048] As described above, the characteristics and advantages of the magnetostrictive guided wave transducer and pipeline inspection system for pipeline inspection of the present invention are: the transducer assembly is connected to the vibrating element, and the vibrating element is in contact with the pipeline to be inspected. The transducer assembly receives the electromagnetic signal and converts it into a first vibration signal. The first vibration signal is transmitted to the pipeline through the vibrating element. The vibration excites the torsional mode guided wave in the pipeline. When the torsional mode guided wave encounters the defect position of the pipeline during the axial propagation along the pipeline, it will generate an echo. The vibration of the echo is the returned second vibration signal. The second vibration signal is transmitted back to the transducer assembly through the vibrating element, thereby enabling long-distance and large-scale non-contact non-destructive inspection of the defect position in the pipeline, with high detection accuracy and long service life.

[0049] In addition, for large-sized pipelines, multiple magnetostrictive guided wave transducers can be arranged in an array along the circumference of the pipeline to excite ultrasonic guided waves in the large-sized pipeline and receive echoes, thereby achieving the purpose of detecting large-sized pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The following drawings are only intended to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0051] in:

[0052] Figure 1 : It is a front view of the magnetostrictive guided wave transducer for pipeline detection of the present invention.

[0053] Figure 2 : It is a front cross-sectional view of the magnetostrictive guided wave transducer for pipeline detection of the present invention.

[0054] Figure 3 : A top view of the magnetostrictive guided wave transducer for pipeline detection according to the present invention.

[0055] Figure 4 : It is a front view of the vibrating element in the magnetostrictive guided wave transducer for pipeline detection of the present invention.

[0056] Figure 5 : It is the right view of the vibrating element in the magnetostrictive guided wave transducer for pipeline detection of the present invention.

[0057] Figure 6 : A schematic diagram of the internal structure of the vibrating element in the magnetostrictive guided wave transducer for pipeline detection according to the present invention, viewed from above.

[0058] Figure 7 : is a structural diagram of the pipeline detection system of the present invention.

[0059] The accompanying drawings in the present invention are:

[0060] 1. Vibrating element; 101. Accommodating space;

[0061] 102. Mounting hole; 103. Second vibration component;

[0062] 104. First vibrating component; 105. Limiting groove;

[0063] 2. Magnetostrictive element; 3. Induction coil assembly;

[0064] 4. Permanent magnet; 5. Housing;

[0065] 501, housing body 502, side panels;

[0066] 503, cover; 6, connector;

[0067] 7. Reed; 8. First bolt;

[0068] 9. Second bolt; 10. Magnetostrictive guided wave transducer for pipeline inspection;

[0069] 20. Pipeline. DETAILED DESCRIPTION

[0070] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0071] Implementation Method 1

[0072] like Figures 1 to 6 As shown, the present invention provides a magnetostrictive guided wave transducer for pipeline detection. The magnetostrictive guided wave transducer for pipeline detection includes at least one vibrating member 1 and a transducer assembly. The transducer assembly can generate a first vibration signal and receive a second vibration signal returned by the pipeline 20. The transducer assembly is connected to the vibrating member 1, and the vibrating member 1 is in contact with the pipeline 20. The transducer assembly transmits the generated first vibration signal to the pipeline 20 through the vibrating member 1. The second vibration signal returned by the defect position of the pipeline 20 is transmitted back to the transducer assembly through the vibrating member 1.

[0073] The present invention connects the transducer assembly to the vibrator 1, and the vibrator 1 contacts the pipeline 20 to be inspected. The transducer assembly receives the electromagnetic signal and converts it into a first vibration signal. The first vibration signal is transmitted to the pipeline 20 through the vibrator 1, and the vibration excites the torsional mode guided wave in the pipeline 20. When the torsional mode guided wave encounters the defect position of the pipeline 20 during the axial propagation along the pipeline 20, an echo is generated. The vibration of the echo is the returned second vibration signal. The second vibration signal is transmitted back to the transducer assembly through the vibrator 1, thereby enabling long-distance and large-scale non-contact non-destructive detection of the defect position in the pipeline 20. The detection accuracy is high and the service life is long. It is suitable for pipeline detection and long-term online monitoring.

[0074] In an optional embodiment of the present invention, Figures 1 to 3 As shown, the transducer component is connected to the connector 6 that can receive and send electromagnetic signals. The transducer component converts the first electrical signal transmitted by the connector 6 into a first vibration signal and transmits it to the pipeline 20, and the transducer component converts the received second vibration signal into a second electrical signal and outputs it externally.

[0075] Furthermore, the connector 6 may be, but is not limited to, an SMA connector (microwave connector) with an SMA connector. The transducer assembly receives the first electromagnetic signal through the SMA connector and converts it into a mechanical signal (i.e., a first vibration signal), which is then output to the pipeline 20 under test in the form of an ultrasonic guided wave. Simultaneously, the transducer assembly converts the received mechanical signal of the defect echo (i.e., a second vibration signal) into a second electromagnetic signal, which is then output as an echo signal through the SMA connector.

[0076] In an optional embodiment of the present invention, Figure 2As shown, the transducer assembly includes a magnetostrictive element 2, an induction coil assembly 3, and a permanent magnet 4. The induction coil assembly 3 is arranged around the outer surface of the magnetostrictive element 2. The magnetostrictive element 2 is connected to a vibrating member 1. The permanent magnet 4 is disposed on the vibrating member 1, and the magnetostrictive element 2 is connected to the vibrating member 1 via the permanent magnet 4. During operation, an electromagnetic signal (i.e., an excitation signal) is input through the SMA connector. The excitation signal generates an alternating magnetic field through the induction coil assembly 3. Under the influence of the alternating magnetic field and the bias magnetic field generated by the permanent magnet 4, the magnetostrictive effect causes the magnetostrictive element 2 to generate periodic vibrations at the same frequency as the electromagnetic signal. This, in turn, drives the vibrating member 1 to vibrate, generating torsional mode ultrasonic guided waves in the pipe 20 through the vibrating member 1.

[0077] Furthermore, the permanent magnet 4 can be made of, but not limited to, a neodymium iron boron magnet.

[0078] In an optional embodiment of the present invention, Figure 2 、 Figures 4 to 6 As shown, the vibrating member 1 includes a second vibrating component 103 and a first vibrating component 104. An accommodating space 101 is formed inside the second vibrating component 103. The permanent magnet 4 is disposed in the accommodating space 101. The second vibrating component 103 is provided with a mounting hole 102 that communicates with the accommodating space 101. The end of the magnetostrictive element 2 extends through the mounting hole 102 into the accommodating space 101 and is connected to the permanent magnet 4. The second vibrating component 103 is connected to one end surface of the first vibrating component 104, and the other opposite end surface of the first vibrating component 104 is in contact with the surface of the pipe 20.

[0079] Among them, the second vibration component 103 is a vertically arranged rectangular block structure, and the first vibration component 104 is a horizontally arranged plate structure. The second vibration component 103 and the first vibration component 104 can be integrally formed. The second vibration component 103 and the first vibration component 104 cooperate to make the vibration element 1 have a "T" shape structure as a whole.

[0080] Furthermore, the vibration member 1 can be made of, but not limited to, 45 steel, silicon steel, or iron-nickel alloy.

[0081] Further, such as Figure 2 、 Figure 6 As shown, a limiting groove 105 is provided in the accommodating space 101 , and the permanent magnet 4 is fixed in the limiting groove 105 .

[0082] Furthermore, the coupling between the vibrator 1 and the pipe 20 can be achieved by, but is not limited to, pressure or magnetism. Ultrasonic coupling agent is applied to the coupling position between the vibrator 1 and the pipe 20 to bond the vibrator 1 and the pipe 20. Of course, other connection methods (such as a clamping connection) can also be used to secure the vibrator 1 to the pipe 20.

[0083] In an optional embodiment of the present invention, Figure 1 、 Figure 2 As shown, there are two vibrating members 1 , which are spaced apart from each other. The magnetostrictive element 2 is a columnar structure, and both ends of the magnetostrictive element 2 extend into the corresponding accommodation spaces 101 of the two vibrating members 1 and are connected to the permanent magnet 4 .

[0084] Furthermore, the two vibrating members 1 and the two permanent magnets 4 are symmetrically arranged.

[0085] Furthermore, the magnetostrictive element 2 and the permanent magnet 4 may be connected by bonding, using but not limited to epoxy resin glue as the adhesive.

[0086] In an optional embodiment of the present invention, Figures 1 to 3 As shown, the magnetostrictive guided wave transducer for pipeline detection also includes a housing 5, one side of the housing 5 (the side close to the pipeline 20 during operation) is open. The two vibrating elements 1 and the transducer assembly are both disposed within the housing 5, and the first vibrating components 104 on the two vibrating elements 1 extend from the open position to the outside of the housing 5 and contact the surface of the pipeline 20. A reed 7 is sandwiched between at least one vibrating element 1 and the inner wall of the housing 5. The reed 7 serves as an elastic member and can ensure a tight fit between the housing 5, the vibrating element 1, and the transducer assembly in the vibration direction, effectively improving the operating performance of the magnetostrictive element 2.

[0087] Furthermore, the housing 5 is made of a magnetic conductive material, wherein the magnetic conductive material may be, but is not limited to, duralumin, industrial pure iron, silicon steel or ferrite.

[0088] Further, such as Figure 2 As shown, a vibrator 1, a transducer assembly, another vibrator 1, and a reed 7 are sequentially compressed within the housing 5, from one inner wall to the opposite inner wall. This arrangement provides prestress along the vibration direction to the magnetostrictive element 2, effectively improving its performance and extending its service life.

[0089] Furthermore, a closed magnetic circuit is formed between the vibrating member 1, the permanent magnet 4, the housing 5 and the magnetostrictive element 2, which effectively reduces the leakage magnetic intensity, increases the magnetization intensity of the magnetostrictive element 2, and improves the electromechanical conversion efficiency.

[0090] Specifically, such as Figures 1 to 3 As shown, the housing 5 includes a housing body 501, a side plate 502 and a cover plate 503. The cover plate 503 is located at a position opposite to the opening, and the two ends of the cover plate 503 are respectively connected to the housing body 501 and the side plate 502, so as to enclose a space for accommodating the vibrator 1 and the transducer assembly between the housing body 501, the side plate 502 and the cover plate 503; the reed 7 is clamped between the vibrator 1 and the side plate 502.

[0091] Furthermore, the cover plate 503 may be made of, but not limited to, industrial pure iron.

[0092] Further, such as Figures 1 to 3 As shown, a first through hole is opened in the middle position of the cover plate 503, and the connector 6 extends to the outside from the first through hole; at least two second through holes are provided on the cover plate 503, and a first bolt 8 is provided in the second through hole. The screw end of the first bolt 8 extends into the shell 5 and is respectively connected to the corresponding vibrator 1. The aperture of the second through hole is larger than the screw diameter of the first bolt 8, so that the vibrator 1 is installed in the shell 5.

[0093] Further, such as Figures 1 to 3 As shown, the side plate 502 is connected to the housing body 501 via a plurality of second bolts 9. By adjusting the screwing position of the second bolts 9, the preload force between the side plate 502 and the reed 7 can be adjusted, thereby adjusting the preload stress on the magnetostrictive element 2.

[0094] In an optional embodiment of the present invention, Figure 2 As shown, the induction coil assembly 3 comprises multiple induction coil segments of equal length. Each segment is arranged axially along the magnetostrictive element 2. Adjacent segments are wound in opposite directions around the magnetostrictive element 2. This ensures that the guided waves excited by each segment generate gain at the same location, resulting in a more effective excitation effect. Furthermore, the length L of each induction coil segment is equal to half the wavelength λ / 2 of the guided wave in the first vibration signal generated by the magnetostrictive element 2. This achieves optimal excitation through the half-wavelength effect.

[0095] Furthermore, at least three layers of induction coil groups 3 are wound on the magnetostrictive element 2 from the inside, and each induction coil group 3 includes three sections of induction coils.

[0096] Furthermore, the induction coil may be made of enameled wire with a diameter of 0.3 mm, and the length of each section of the induction coil may be, but is not limited to, 10 mm.

[0097] In an optional embodiment of the present invention, Figure 2 As shown, the magnetostrictive element 2 has a columnar (or rod-shaped) structure, and the resonant frequency of the magnetostrictive element 2 is equal to the frequency of the magnetostrictive element 2 exciting the guided wave, and the length of the magnetostrictive element 2 satisfies the following formula:

[0098]

[0099] Where l is the length of the magnetostrictive element; f is the resonant frequency; E 33 is the Young's modulus of the magnetostrictive element along the vibration direction; ρ is the density along the vibration direction.

[0100] In a specific embodiment, the length l of the magnetostrictive element 2 may be 30 mm, the diameter of the magnetostrictive element 2 may be 8 mm, and the resonant frequency of the magnetostrictive element 2 and the frequency of the guided wave excited by the magnetostrictive element 2 are both 100 kHz.

[0101] In an optional embodiment of the present invention, the magnetostrictive element 2 is a composite material, comprising a terbium-dysprosium-iron alloy strip, an adhesive, a coupling agent, a curing agent, and a defoaming agent, wherein the terbium-dysprosium-iron alloy strip is 30 to 70 parts, the thickness of the terbium-dysprosium-iron alloy strip is 45 μm to 1000 μm, the width of the terbium-dysprosium-iron alloy strip is 1.0 mm to 20.0 mm, the adhesive is 20 to 30 parts, the coupling agent is 0.3 to 0.7 parts, and the curing agent and the defoaming agent are 0.2 to 0.3 parts in total. The chemical formula of the terbium-dysprosium-iron alloy strip is Tb x Dy 1-x Fe y ; Among them, 0.27≤x≤0.4, 1.8≤y≤2.

[0102] In an optional embodiment of the present invention, the chemical formula of the terbium-dysprosium-iron alloy strip is Tb 0.3 Dy 0.7 The preparation method of the Fe2 magnetostrictive element 2 comprises the following steps:

[0103] Step S1: Suspension melting to form Tb 0.3 Dy 0.7 Fe2 alloy ingot;

[0104] Step S2: Tb 0.3 Dy 0.7 The Fe2 alloy ingot is heated until it melts;

[0105] Specifically, Tb 0.3 Dy 0.7 The Fe2 alloy ingot is placed in the induction coil of the vacuum belt furnace, and the vacuum chamber is evacuated to a vacuum degree less than or equal to 2.0×10 -3 Pa, then argon gas was introduced to a pressure of 0.020 MPa; under the protection of argon gas, medium frequency induction heating of Tb 0.3 Dy 0.7 Fe2 alloy ingot until melted.

[0106] Step S3: melt Tb 0.3 Dy 0.7 Fe2 liquid alloy is sprayed onto a copper roller with a rotating speed to obtain Tb 0.3 Dy 0.7 Fe2 alloy strip;

[0107] Among them, the copper roller is a water-cooled copper roller, and the rotation speed of the copper roller is 300 revolutions / min.

[0108] Among them, the obtained Tb 0.3 Dy 0.7 The Fe2 alloy strip has a thickness of 200 μm and a width of 1.5 mm.

[0109] Step S4: A certain amount of Tb is treated with an ethanol solution mixed with polydimethylsiloxane. 0.3 Dy 0.7 The surface of the Fe2 alloy strip is treated;

[0110] Specifically, Tb 0.3 Dy 0.7 The Fe2 alloy strip was added into an ethanol solution mixed with polydimethylsiloxane, and the solution was filtered out after treatment for 20 minutes, and the surface treated Tb was obtained by drying. 0.3 Dy 0.7 Fe2 alloy strip, treated Tb 0.3 Dy 0.7 The surface of the Fe2 alloy strip has better adhesion.

[0111] Step S5: According to the preset mixing ratio, Tb 0.3 Dy 0.7 The Fe2 alloy strip, the adhesive, the coupling agent, the curing agent and the defoaming agent are mixed to form a first premixture;

[0112] Step S6: transferring the first premixture into a mold cavity of a preset shape (the mold can be made according to the shape of the magnetostrictive element 2 ), and performing a degassing treatment on the first premixture under a vacuum environment;

[0113] Specifically, the vacuum environment of the mold is less than or equal to 10 -3 Pa, the defoaming time is 20min to 40min.

[0114] Step S7: The first premixture in the mold cavity is cured (requiring 2 to 5 hours) and then hardened (8 to 24 hours) to obtain the magnetostrictive element 2. During the curing process of the first premixture, certain magnetic field, pressure, and temperature conditions can be set to ensure smooth curing of the first premixture.

[0115] In this embodiment, the Tb-Dy-Fe alloy strip is oriented in the thickness direction. <110> or <112> , each terbium-dysprosium-iron alloy strip is arranged along the direction of the magnetic field.

[0116] In another optional embodiment of the present invention, the chemical formula of the terbium-dysprosium-iron alloy strip is Tb 0.3 Dy 0.7 The preparation method of the Fe2 magnetostrictive element 2 comprises the following steps:

[0117] Step S1': Suspension melting to form Tb 0.3 Dy 0.7 Fe2 alloy ingot;

[0118] Step S2': Tb 0.3 Dy 0.7 The Fe2 alloy ingot was crushed in an argon atmosphere, ball-milled and sieved to obtain Tb with a particle size of 200 μm to 250 μm. 0.3 Dy 0.7 Fe2 alloy particles;

[0119] Step S3': Tb 0.3 Dy 0.7 Fe2 alloy particles were added to an ethanol solution mixed with polydimethylsiloxane, and the solution was filtered out after treatment for 20 minutes, and the surface-treated Tb was obtained by drying. 0.3 Dy 0.7 Fe2 alloy particles, treated Tb 0.3 Dy 0.7 The surface of Fe2 particles has better adhesion;

[0120] Step S4': According to the preset mixing ratio, Tb 0.3 Dy 0.7 The Fe2 alloy particles, the binder, the coupling agent, the curing agent and the defoaming agent are mixed to form a second premixture;

[0121] Step S5': transferring the second premixture into a mold cavity of a preset shape (the mold can be made according to the shape of the magnetostrictive element 2), and performing a degassing treatment on the second premixture under a vacuum environment;

[0122] Specifically, the vacuum environment of the mold is less than or equal to 10 -3 Pa, the defoaming time is 20min to 40min.

[0123] Step S6': The second premixture in the mold cavity is cured (requiring 2 to 5 hours), and then hardened (8 to 24 hours) to obtain the magnetostrictive element 2. During the curing process of the second premixture, specific magnetic field, pressure, and temperature conditions can be set to ensure smooth curing of the second premixture.

[0124] The characteristics and advantages of the magnetostrictive guided wave transducer for pipeline detection of the present invention are:

[0125] 1. This magnetostrictive guided wave transducer for pipeline inspection excites torsional mode guided waves in the pipeline 20 through vibration. When the torsional mode guided waves encounter defective locations in the pipeline 20 during axial propagation along the pipeline 20, an echo is generated, so that the returned vibration signal is transmitted back to the transducer component through the vibrator 1. This allows long-distance, large-scale, non-contact, non-destructive inspection of defective locations in the pipeline 20, with high detection accuracy and a long service life.

[0126] 2. In the magnetostrictive guided wave transducer for pipeline detection, the magnetostrictive element 2 is a magnetostrictive composite material. Using this magnetostrictive composite material as a functional element for transmitting and receiving guided waves has good processing performance, simple preparation process, low cost, and has a promising future for promotion in actual production.

[0127] 3. In the magnetostrictive guided wave transducer for pipeline detection, the magnetostrictive element 2 has good magnetostrictive performance, high resistivity, small eddy current effect under high-frequency magnetic field conditions, and high electromechanical conversion efficiency, which perfectly meets the performance requirements of the ultrasonic guided wave transducer.

[0128] Fourth, this magnetostrictive guided wave transducer for pipeline inspection adopts a structure in which the magnetostrictive element 2 is coordinated with the vibrating element 1. This avoids direct contact between the magnetostrictive element 2 and the surface of the pipeline 20 to be tested, reduces the wear of the magnetostrictive element 2 during use, and simultaneously applies a certain pre-compression stress to the magnetostrictive element 2, effectively extending the service life of the magnetostrictive element 2.

[0129] 5. The magnetostrictive guided wave transducer for pipeline detection has the characteristics of simple structure and high electromechanical conversion efficiency. It is suitable for long-distance non-contact detection of the pipeline 20 and is also suitable for long-term online monitoring of the pipeline 20. By being arranged along the circumference of the pipeline 20, it can be applied to the detection of large-sized pipelines 20.

[0130] Implementation Method 2

[0131] like Figure 7 As shown, the present invention provides a pipeline detection system, which includes a plurality of the aforementioned magnetostrictive guided wave transducers 10 for pipeline detection. Each magnetostrictive guided wave transducer 10 for pipeline detection is arranged on the outer wall of the pipeline 20 along the circumference of the pipeline 20, and the vibrating element 1 in each magnetostrictive guided wave transducer 10 for pipeline detection is in contact with the outer wall of the pipeline 20.

[0132] Furthermore, the magnetostrictive guided wave transducers 10 for pipeline detection are spaced and symmetrically arranged on the outer wall of the pipeline 20 .

[0133] In an optional embodiment of the present invention, the pipeline detection system further includes an ultrasonic guided wave detection device (an existing device or system), and the induction coil group 3 in each magnetostrictive guided wave transducer 10 used for pipeline detection is connected in series through a corresponding connector 6 and then connected to an external ultrasonic guided wave detection device.

[0134] During use, the pipeline detection system of the present invention is suitable for detecting large-diameter pipelines 20. Each magnetostrictive guided wave transducer 10 for pipeline detection is arranged on the outer wall of the pipeline 20 along the circumference of the pipeline 20 to excite torsional mode guided waves in the pipeline 20. The ultrasonic guided wave detection device inputs an electromagnetic signal (i.e., an excitation signal) into each magnetostrictive guided wave transducer 10 for pipeline detection. The excitation signal generates an alternating magnetic field through each induction coil group 3. Under the action of the alternating magnetic field and the bias magnetic field generated by the permanent magnet 4, due to the magnetostrictive effect, the magnetostrictive element 2 generates a periodic frequency with the same frequency as the electromagnetic signal. Vibration drives each vibrator 1 to vibrate (i.e., generating a first vibration signal). Vibrators 1 generate torsional ultrasonic guided waves in pipeline 20. These waves propagate axially within pipeline 20, reflecting at defects in pipeline 20 and generating reverse defect echoes. These echoes propagate in the reverse direction, passing through each magnetostrictive guided wave transducer 10 used for pipeline inspection. These echoes drive the corresponding magnetostrictive elements 2 to vibrate (i.e., generating a second vibration signal). Due to the inverse magnetostrictive effect, the magnetization intensity within each magnetostrictive element 2 changes, inducing electromagnetic signals (i.e., echo signals) in each induction coil assembly 3. By transmitting these echo signals to an ultrasonic guided wave inspection device and comparing the time difference between the excitation signal and the echo signal, combined with the wave velocity of the guided wave propagation, the location of the defect in pipeline 20 can be determined, achieving the purpose of pipeline 20 inspection.

[0135] The characteristics and advantages of the pipeline detection system of the present invention are:

[0136] In this pipeline detection system, the layout of the magnetostrictive guided wave transducer 10 for pipeline detection can improve the electromechanical conversion efficiency of the signal, thereby receiving an echo signal with a larger amplitude and better identifiability; by changing the setting direction of the magnetostrictive guided wave transducer 10 for pipeline detection, longitudinal mode guided waves can also be excited in the pipeline 20, thereby meeting the detection requirements of pipelines 20 of different sizes.

[0137] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A magnetostrictive guided wave transducer for pipeline detection, characterized in that: The invention comprises at least one vibrating member and a transducer assembly capable of generating a first vibration signal and receiving a second vibration signal returned by the pipeline, wherein the transducer assembly is connected to the vibrating member, and the vibrating member is in contact with the pipeline; The transducer assembly transmits the generated first vibration signal to the pipeline via the vibrating element; The second vibration signal returned by the defective position of the pipeline is transmitted back to the transducer component through the vibrating element; The energy conversion assembly includes a magnetostrictive element, an induction coil group and a permanent magnet, wherein the induction coil group is arranged on the magnetostrictive element, the permanent magnet is arranged on the vibrating element, and the magnetostrictive element is connected to the vibrating element through the permanent magnet; The vibrating member includes a first vibrating component and a second vibrating component. The second vibrating component has an interior formed with an accommodating space, the permanent magnet is disposed in the accommodating space, the second vibrating component is provided with a mounting hole communicating with the accommodating space, the end of the magnetostrictive element extends through the mounting hole into the accommodating space and is connected to the permanent magnet, the second vibrating component is connected to one end surface of the first vibrating component, and the other opposite end surface of the first vibrating component is in contact with the surface of the pipe; The magnetostrictive guided wave transducer for pipeline detection further includes a housing, one side of the housing being open, the two vibrating members and the transducer assembly being disposed within the housing, and the first vibrating components on the two vibrating members extending from the open position to the outside of the housing and in contact with the surface of the pipeline; a reed is sandwiched between at least one of the vibrating members and the inner wall of the housing; One of the vibrating members, the energy conversion assembly, the other vibrating member and the reed are sequentially compressed and arranged in the housing from one inner wall to the other opposite inner wall.

2. The magnetostrictive guided wave transducer for pipeline detection according to claim 1, characterized in that: The transducer component is connected to a connector that can receive and send electromagnetic signals. The transducer component converts the first electrical signal transmitted by the connector into the first vibration signal and transmits it to the pipeline, and the transducer component converts the received second vibration signal into a second electrical signal and outputs it to the outside.

3. The magnetostrictive guided wave transducer for pipeline detection according to claim 1, characterized in that: A limiting groove is provided in the accommodating space, and the permanent magnet is fixed in the limiting groove.

4. The magnetostrictive guided wave transducer for pipeline detection according to claim 3, characterized in that: There are two vibrating members, which are spaced apart from each other. The magnetostrictive element is a columnar structure, and both ends of the magnetostrictive element extend into the accommodating spaces corresponding to the two vibrating members, respectively.

5. The magnetostrictive guided wave transducer for pipeline detection according to claim 1, characterized in that: A closed magnetic circuit is formed among the vibrating member, the permanent magnet, the housing and the magnetostrictive element.

6. The magnetostrictive guided wave transducer for pipeline detection according to claim 2, characterized in that: The shell includes a shell body, a side plate and a cover plate. The cover plate is located at a position opposite to the opening, and the two ends of the cover plate are respectively connected to the shell body and the side plate to enclose a space for accommodating the vibrator and the transducer assembly between the shell body, the side plate and the cover plate; the reed is clamped between the vibrator and the side plate.

7. The magnetostrictive guided wave transducer for pipeline detection according to claim 6, characterized in that: A first through hole is formed on the cover plate, and the connector extends to the outside through the first through hole; At least two second through holes are provided on the cover plate, and first bolts are provided in the second through holes. The screw ends of the first bolts extend into the housing and are respectively connected to the corresponding vibrating members.

8. The magnetostrictive guided wave transducer for pipeline detection according to claim 1, characterized in that: The induction coil group includes multiple induction coils of the same length, wherein the winding directions of two adjacent induction coils on the magnetostrictive element are opposite, and the length of each induction coil is equal to half the wavelength of the guided wave in the first vibration signal generated by the magnetostrictive element.

9. The magnetostrictive guided wave transducer for pipeline detection according to claim 8, characterized in that: At least three layers of induction coil groups are wound on the magnetostrictive element from the inside, and the number of induction coils in each induction coil group is three.

10. The magnetostrictive guided wave transducer for pipeline detection according to claim 1, characterized in that: The magnetostrictive element has a columnar structure, and the resonant frequency of the magnetostrictive element is equal to the frequency of the magnetostrictive element exciting the guided wave, and the length of the magnetostrictive element satisfies the following formula: Where l is the length of the magnetostrictive element; f is the resonant frequency; E 33 is the Young's modulus of the magnetostrictive element along the vibration direction; ρ is the density along the vibration direction.

11. The magnetostrictive guided wave transducer for pipeline detection according to claim 1, characterized in that: The magnetostrictive element is a composite material, comprising a terbium-dysprosium-iron alloy strip, an adhesive, a coupling agent, a curing agent, and a defoaming agent. The terbium-dysprosium-iron alloy strip accounts for 30 to 70 parts, has a thickness of 45 μm to 1000 μm, has a width of 1.0 mm to 20.0 mm, contains 20 to 30 parts of the adhesive, contains 0.3 to 0.7 parts of the coupling agent, and contains a total of 0.2 to 0.3 parts of the curing agent and the defoaming agent.

12. The magnetostrictive guided wave transducer for pipeline detection according to claim 11, characterized in that: The chemical formula of the terbium-dysprosium-iron alloy strip is Tb x Dy 1-x Fe y ; Among them, 0.27≤x≤0.4, 1.8≤y≤2.

13. The magnetostrictive guided wave transducer for pipeline detection according to claim 12, characterized in that: The chemical formula of the terbium-dysprosium-iron alloy strip is Tb 0.3 Dy 0.7 Fe2, the preparation method of the magnetostrictive element comprises the following steps: Step S1: Smelting to form Tb 0.3 Dy 0.7 Fe2 alloy ingot; Step S2: Tb 0.3 Dy 0.7 The Fe2 alloy ingot is heated until it melts; Step S3: melt Tb 0.3 Dy 0.7 Fe2 liquid alloy is sprayed onto a copper roller with a rotating speed to obtain Tb 0.3 Dy 0.7 Fe2 alloy strip; Step S4: using an ethanol solution mixed with polydimethylsiloxane to 0.3 Dy 0.7 The surface of the Fe2 alloy strip is treated; Step S5: Tb 0.3 Dy 0.7 The Fe2 alloy strip, the adhesive, the coupling agent, the curing agent and the defoaming agent are mixed to form a first premixture; Step S6: transferring the first premixture into a mold cavity of a preset shape, and performing a degassing treatment on the first premixture under a vacuum environment; Step S7: curing and molding the first premixture in the mold cavity to obtain the magnetostrictive element.

14. The magnetostrictive guided wave transducer for pipeline detection according to claim 12, characterized in that: The chemical formula of the terbium-dysprosium-iron alloy strip is Tb 0.3 Dy 0.7 Fe2, the preparation method of the magnetostrictive element comprises the following steps: Step S1': Smelting to form Tb 0.3 Dy 0.7 Fe2 alloy ingot; Step S2': Tb 0.3 Dy 0.7 The Fe2 alloy ingots were crushed and sieved to obtain Tb 0.3 Dy 0.7 Fe2 alloy particles; Step S3': Tb 0.3 Dy 0.7 Fe2 alloy particles were added into an ethanol solution mixed with polydimethylsiloxane, and the Tb 0.3 Dy 0.7 The surface of the Fe2 alloy particles is treated; Step S4': Tb 0.3 Dy 0.7 The Fe2 alloy particles, the binder, the coupling agent, the curing agent and the defoaming agent are mixed to form a second premixture; Step S5': transferring the second premixture into a mold cavity of a preset shape, and performing a degassing treatment on the second premixture under a vacuum environment; Step S6 ′: curing and molding the second premixture in the mold cavity to obtain the magnetostrictive element.

15. A pipeline detection system, characterized in that: The invention comprises a plurality of magnetostrictive guided wave transducers for pipeline detection according to any one of claims 1 to 14, wherein each of the magnetostrictive guided wave transducers for pipeline detection is arranged on the outer wall of the pipeline along the circumference of the pipeline, and the vibrating element in each of the magnetostrictive guided wave transducers for pipeline detection is in contact with the outer wall of the pipeline.

16. The pipeline detection system according to claim 15, characterized in that: The pipeline detection system further includes an ultrasonic guided wave detection device, and the induction coil groups in the magnetostrictive guided wave transducers for pipeline detection are connected in series through corresponding connectors and then connected to the ultrasonic guided wave detection device.

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