CN110568060A - Coil self-excited ferromagnetic pipeline electromagnetic ultrasonic transducer, excitation device and receiving device - Google Patents

Coil self-excited ferromagnetic pipeline electromagnetic ultrasonic transducer, excitation device and receiving device Download PDF

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CN110568060A
CN110568060A CN201910980409.7A CN201910980409A CN110568060A CN 110568060 A CN110568060 A CN 110568060A CN 201910980409 A CN201910980409 A CN 201910980409A CN 110568060 A CN110568060 A CN 110568060A
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electromagnetic ultrasonic
ultrasonic transducer
phase coil
coil group
phase
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王晓红
杨嘉欣
黄超
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Xiamen University
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/72Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
    • G01N27/82Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/34Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor
    • G01N29/346Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor with amplitude characteristics, e.g. modulated signal
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00Indexing codes associated with group G01N29/00
    • G01N2291/02Indexing codes associated with the analysed material
    • G01N2291/023Solids
    • G01N2291/0234Metals, e.g. steel

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Abstract

the invention discloses a coil self-excited ferromagnetic pipeline electromagnetic ultrasonic transducer, an excitation device and a receiving device, which comprise: skeleton, normal phase coil assembly, reverse phase coil assembly. The electromagnetic ultrasonic transducer automatically generates an external bias magnetic field while exciting a pulse magnetic field in a ferromagnetic pipeline to be detected through an exciting current with a special waveform. The alternating distributed magnetostriction effect generated by the normal-phase coil group and the reverse-phase coil group meets the matching relation of ultrasonic constructive interference, so that the electromagnetic ultrasonic longitudinal guided wave propagating along the axial direction is excited in the ferromagnetic pipeline. The invention also discloses an electromagnetic ultrasonic excitation device and an electromagnetic ultrasonic receiving device using the transducer. The electromagnetic ultrasonic transducer disclosed by the invention does not need to be provided with a direct current coil and an alternating current coil, has a simpler structure, is provided with a corresponding excitation device and a corresponding receiving device, does not need to use a rigid permanent magnet to provide a bias magnetization field, and reduces the volume of the device.

Description

Coil self-excited ferromagnetic pipeline electromagnetic ultrasonic transducer, excitation device and receiving device
Technical Field
the invention relates to the field of electromagnetic ultrasonic guided wave detection technology and equipment, in particular to an electromagnetic ultrasonic transducer applied to ferromagnetic pipelines, which can be used for nondestructive detection of defects of ferromagnetic pipelines such as iron pipes, steel pipes and the like.
Background
With the rapid development of the energy industry such as natural gas and petroleum, pipeline transportation has the advantages of high efficiency, low loss, low cost and the like, and is increasingly emphasized by the industrial field, and the pipelines are mainly ferromagnetic pipelines. However, ferromagnetic pipelines have weak corrosion resistance and are prone to crack, corrosion and other defects under severe working conditions in the pipelines. If the defects cannot be checked and disposed in time, further pipeline leakage and explosion can be caused, and huge economic loss and casualties are caused.
Among various nondestructive testing technologies, the electromagnetic ultrasonic testing technology has the characteristic of non-contact, can excite ultrasonic waves on the surface of a metal material, and is high in testing speed and convenient to use. At present, the electromagnetic ultrasonic detection technology is widely applied to the fields of petrifaction, high-speed rail, aviation, aerospace and the like.
In the electromagnetic ultrasonic detection technology, two effects of generating electromagnetic ultrasonic are as follows: lorentz force effect and magnetostriction effect. For ferromagnetic materials, the effect of the magnetostrictive effect is more prominent, so in ferromagnetic pipelines, the magnetostrictive effect is mostly used to excite ultrasonic waves. The electromagnetic ultrasonic transducer generates a magnetostrictive effect in the ferromagnetic material by radiating a pulse magnetic field outwards and the composite action of the pulse magnetic field and the external magnetic field.
Chinese patent CN 103616441 a discloses an electromagnetic ultrasonic signal excitation device for ferromagnetic materials. The ultrasonic signal of separating longitudinal wave from transverse wave can be excited by adopting the transduction mechanism of electromagnetic ultrasonic, and the ultrasonic signal is used for online detection of tiny defects in the ferromagnetic material sheet. An electromagnet is used for providing a magnetic field, an electromagnetic ultrasonic transduction mechanism is taken as a technical core, and excited Lorentz force and magnetostrictive force are orthogonally decomposed.
Chinese patent CN104122330B discloses a pipeline defect detection method based on electromagnetic ultrasonic longitudinal guided waves, which comprises arranging a plurality of ring magnets coaxially arranged with the pipeline to generate a radial static magnetic field on the surface of the pipeline; solenoid coils are coaxially sleeved on two sides of each loop magnet array, so that circumferential induction eddy current is generated in the pipeline to be detected; under the combined action of the circumferential induced eddy current and the radial static magnetic field, longitudinal mode guided waves are excited. In the invention, a plurality of groups of permanent magnets are needed, and the current directions of a plurality of solenoid coils are different, so that generated eddy currents are easy to interfere with each other.
chinese patent CN 108088907A discloses an electromagnetic ultrasonic-based high-temperature pipeline damage online monitoring system, which can quickly scan the distribution situation of defects in a pipeline at a longer distance and can install a transducer and a hardware circuit system on the pipeline for a long time; the heat of the pipeline is converted into electric energy through a thermoelectric conversion circuit, and the system is powered when the system works; a large amount of data can be accumulated, and the sensitivity of the system and the reliability of results are improved through comprehensive analysis of the data.
however, the electromagnetic ultrasonic transducer used for detecting the pipeline defects at present mainly has the following defects: firstly, the electromagnetic ultrasonic transducer is mainly excited by adopting a Lorentz force effect, and the online pipeline is mostly a ferromagnetic pipeline, so that the efficiency of ultrasonic excitation is not high; secondly, the electromagnetic ultrasonic transducer adopts a rigid magnet to provide a bias magnetic field, and the probe is large in size and is not suitable for the requirements of miniaturization and portability of the electromagnetic ultrasonic transducer for pipeline defect detection.
Disclosure of Invention
In order to solve the above problems, the present invention provides a ferromagnetic conduit electromagnetic ultrasonic transducer with a self-excited coil. The transducer does not need a strong magnet to provide a static magnetic field or a direct current coil to form an electromagnet, and can automatically generate an additional bias magnetic field while exciting a pulse magnetic field in a ferromagnetic pipeline to be detected through exciting current with a special waveform. A bias magnetic field and a pulse magnetic field formed by self excitation of the coil generate a magnetostrictive effect on the wall of the ferromagnetic pipeline and form electromagnetic ultrasonic longitudinal guided waves.
In order to achieve the purpose, the invention adopts the following technical scheme:
A coil self-excited ferromagnetic conduit electromagnetic ultrasonic transducer comprising: a framework, a normal phase coil group and a reverse phase coil group, wherein,
the framework is a hollow cylindrical pipe made of insulating materials, the inner diameter of the hollow cylindrical pipe is slightly larger than the outer diameter of the ferromagnetic pipeline to be detected, the hollow cylindrical pipe is coaxially sleeved on the outer surface of the pipeline, 2n annular wire grooves are formed in the upper surface of the framework at equal intervals, the interval between the wire grooves is 1/2 of the wavelength of the excited ultrasonic wave, n is related to the number of the excited electromagnetic ultrasonic pulses, and can be 3-10 generally.
the normal phase coil group is formed by connecting n normal phase coils in series, wherein n can be 3 ~ 10 generally, the normal phase coils are annular coils, the number of turns of each normal phase coil is equal, and the normal phase coils are wound in odd number wire grooves of the framework;
the reverse phase coil group is formed by connecting n reverse phase coils in series, n can be 3 ~ 10 generally, the reverse phase coils are annular coils and are wound in even ~ number wire grooves of the framework, the reverse phase coils and the normal phase coils are wound in the same direction, and the number of turns of the reverse phase coils is equal to that of the normal phase coils.
When the ferromagnetic pipeline electromagnetic ultrasonic transducer with the self-excited coil is used as an excitation end, excitation of the positive-phase coil group and the negative-phase coil group is direct-current pulse current; the direct current pulse current comprises direct current bias current and sine pulse fluctuation, and the amplitude of the sine pulse fluctuation is smaller than the direct current bias current; further, the direct current bias current acting on the excitation of the positive phase coil assembly and the direct current bias current acting on the excitation of the reverse phase coil assembly are in the same direction; and the phase difference between the sine pulse wave phase acted on the excitation of the positive phase coil group and the sine pulse wave phase acted on the excitation of the negative phase coil group is 180 degrees.
when the ferromagnetic pipeline electromagnetic ultrasonic transducer with the self-excited coil is used as a receiving end, the excitation of the positive phase coil assembly and the negative phase coil assembly is direct current bias current in the same direction.
Another object of the present invention is to provide a ferromagnetic conduit electromagnetic ultrasonic excitation device with self-excitation of coil, comprising: electromagnetic ultrasonic transducer, high-power constant current source, pulse signal source, phase inverter, normal phase power amplifier, reverse phase power amplifier, and isolation capacitor,
the electromagnetic ultrasonic transducer is a ferromagnetic pipeline electromagnetic ultrasonic transducer with a coil self-excited, and is arranged on a ferromagnetic pipeline to be tested;
the high-power constant current source generates two paths of direct current bias current outputs with the same size and direction; the first output is connected with a normal phase coil group of the electromagnetic ultrasonic transducer, and the second output is connected with an inverse phase coil group of the electromagnetic ultrasonic transducer.
the pulse signal source generates sinusoidal pulse signals, the number of the pulses is 3 ~ 8, the output of the pulse signal source is divided into two paths, the first path of output is connected with the input end of the positive phase power amplifier, and the second path of output is connected with the input end of the reverse phase power amplifier after passing through the phase inverter.
The isolation capacitor is an electrodeless capacitor and is used for isolating direct current bias current so as to prevent the output of the high-power constant current source from causing current reverse flow to the positive-phase power amplifier or the negative-phase power amplifier.
The output of the normal phase power amplifier is connected with a normal phase coil group of the electromagnetic ultrasonic transducer after passing through an isolation capacitor; the peak current output by the positive phase power amplifier is smaller than the direct current bias current of the high-power constant current source.
the output of the inverting power amplifier is connected with an inverting coil group of the electromagnetic ultrasonic transducer after passing through another isolating capacitor; the peak current output by the inverting power amplifier is smaller than the direct current bias current of the high-power constant current source.
When the excitation device works, the normal phase coil group and the reverse phase coil group of the electromagnetic ultrasonic transducer obtain the excitation of direct current bias current in the same direction to form a unidirectional bias magnetization field to axially magnetize the ferromagnetic pipeline. However, in the magnetization process, the excitation of the normal-phase coil assembly also includes sinusoidal pulse fluctuation, so that the ferromagnetic material in the tube wall below the normal-phase coil assembly generates a periodic magnetostriction effect. Similarly, the ferromagnetic material in the tube wall below the phase-reversal coil group generates a magnetostrictive effect with a phase difference of 180 °.
because the center distance between the normal phase coil and the reverse phase coil is 1/2 of the designed ultrasonic wavelength, the magnetostrictive effect generated by the two coil groups meets the matching relation of ultrasonic constructive interference, and electromagnetic ultrasonic longitudinal guided waves propagating along the axial direction are excited in the ferromagnetic pipeline.
it is still another object of the present invention to provide a ferromagnetic conduit electromagnetic ultrasonic receiving device with self-excitation coil, comprising: an electromagnetic ultrasonic transducer, a high-power constant current source, a coupling capacitor, a signal conditioning circuit, an acquisition circuit and an upper computer, wherein,
The electromagnetic ultrasonic transducer is a ferromagnetic pipeline electromagnetic ultrasonic transducer excited by a coil and is arranged on a ferromagnetic pipeline to be tested;
the high-power constant current source generates two paths of direct current bias current outputs with the same size and direction; the first output is connected with a normal phase coil group of the electromagnetic ultrasonic transducer, and the second output is connected with an inverse phase coil group of the electromagnetic ultrasonic transducer.
The input end of the signal conditioning circuit is connected with a normal phase coil group or a reverse phase coil group of the electromagnetic ultrasonic transducer through a coupling capacitor and is used for acquiring the electromagnetic ultrasonic signals transmitted in the pipeline.
The input end of the acquisition circuit is connected with the output end of the signal conditioning circuit and is used for converting the electromagnetic ultrasonic signals into digital signals; the output end of the acquisition circuit is connected with an upper computer through a data bus and is used for uploading the digitized ultrasonic signals to the upper computer for processing.
when the receiving device works, the normal phase coil group and the reverse phase coil group of the electromagnetic ultrasonic transducer obtain the excitation of direct current bias current with the same direction, and a unidirectional bias magnetization field is formed to axially magnetize the ferromagnetic pipeline. When the ultrasonic wave propagates to the lower part of the normal phase coil group or the reverse phase coil group, the reverse magnetostriction effect is generated under the action of the bias magnetization field, and a voltage signal corresponding to the ultrasonic wave, namely an ultrasonic wave signal, is induced in the normal phase coil group or the reverse phase coil group.
The invention has the beneficial effects that: the invention provides a ferromagnetic pipeline electromagnetic ultrasonic transducer with a self-excited coil, which applies direct current pulse current to a positive phase coil group and a negative phase coil group, and generates a periodic magnetostriction effect with alternately distributed phases while generating a bias magnetization field. Therefore, in the electromagnetic ultrasonic transducer, a direct current coil and an alternating current coil are not required to be arranged, and the structure is simpler. The excitation device and the receiving device do not need to use a rigid permanent magnet to provide a bias magnetization field, so that the volume of the device is reduced.
Drawings
FIG. 1 is a schematic axial sectional view of a first embodiment of the present invention;
FIG. 2 is a comparison of excitation current waveforms when used as an excitation terminal according to an embodiment of the present invention;
FIG. 3 is an axial cross-sectional structural view of the magnetization field distribution at time T1 in accordance with one embodiment of the present invention;
FIG. 4 is an axial cross-sectional structural view of the magnetization field distribution at time T2 in accordance with one embodiment of the present invention;
FIG. 5 is a block diagram of the second embodiment of the present invention;
FIG. 6 is a block diagram of a third embodiment of the present invention;
Reference numbers for the various components in the figures: 1. a framework; 2. a normal phase coil group; 3. an inverting coil group; 4. a wire slot; 5. an electromagnetic ultrasonic transducer; 6. a high-power constant current source; 7. a pulse signal source; 8. an inverter; 9. a positive phase power amplifier; 10. an inverting power amplifier; 11. an isolation capacitor; 12. a coupling capacitor; 13. a signal conditioning circuit; 14. an acquisition circuit; 15. an upper computer; 16. and (5) testing the ferromagnetic pipeline.
Detailed Description
The present invention will be further described with reference to the following specific embodiments. These examples are intended to illustrate the invention and are not intended to limit the scope of the invention.
example one
Referring to fig. 1, a schematic structural diagram of a first embodiment of the present invention provides a ferromagnetic pipeline electromagnetic ultrasonic transducer with a self-excited coil, including: a framework 1, a normal phase coil group 2 and a reverse phase coil group 3, wherein,
The framework 1 is a hollow cylindrical tube made of insulating material, the inner diameter of the hollow cylindrical tube is slightly larger than the outer diameter of the ferromagnetic pipeline to be detected, and the hollow cylindrical tube is coaxially sleeved on the outer surface of the pipeline. 6 annular wire grooves 4 are formed in the upper surface of the framework 1 at equal intervals; the distance between the wire grooves 4 is 5mm, which is 1/2 of the wavelength of the excited ultrasonic wave.
The positive phase coil group 2 is formed by connecting 3 positive phase coils in series; the normal phase coil is an annular coil; the number of turns of each normal phase coil is 9, and a copper enameled wire with the diameter phi 1 mm is wound in the odd-numbered wire grooves 4 of the framework 1;
The phase reversal coil group 3 is formed by connecting 3 phase reversal coils in series; the reverse phase coil is an annular coil and is wound in the even number wire slots 4 of the framework 1; the winding directions and the number of turns of the reverse phase coil and the normal phase coil are the same.
Referring to fig. 2, a waveform diagram of an excitation current when the coil assembly of the present invention is used as an excitation terminal is shown, wherein (a) the diagram shows an excitation current of the positive phase coil assembly 2, and (b) the diagram shows an excitation current of the negative phase coil assembly 3.
The positive phase coil assembly 2 is excited by a direct current pulse current which contains a direct current bias current of 5A and a sinusoidal pulse fluctuation with an amplitude of 3A. The sinusoidal pulse undulation contained 5 complete sinusoidal waves with a frequency of 290 kHz. The excitation current applied to the reverse-phase coil assembly 3 also contains a direct-current bias current of 5A, but the phase difference between the sine pulse fluctuation phase and the sine pulse fluctuation phase of the normal-phase coil assembly 2 is 180 °.
referring to FIG. 3, the magnetization field distribution at time T1 according to an embodiment of the present invention is shown. As can be seen from fig. 2, at time T1, the excitation current applied to the positive phase coil group 2 is 8A, and the excitation current applied to the negative phase coil group 3 is 2A. Therefore, at the time T1, the magnetization field generated by the coil group 2 of the positive phase is stronger than the magnetization field generated by the coil group 3 of the negative phase.
Referring to FIG. 4, the magnetization field distribution at time T2 according to an embodiment of the present invention is shown. As can be seen from fig. 2, at time T1, the excitation current applied to the positive phase coil group 2 is 2A, and the excitation current applied to the negative phase coil group 3 is 8A. Therefore, at time T2, the magnetization field generated by the coil group 2 of the positive phase is smaller in intensity than the magnetization field generated by the coil group 3 of the negative phase.
thus, the magnetization field strength is alternately distributed along the axial direction of the ferromagnetic pipeline 16 to be measured, and the distance between the magnetization field strength and the ferromagnetic pipeline is 1/2 of the designed ultrasonic wavelength. Therefore, the magnetostrictive effect caused by the transducer meets the matching relation of ultrasonic constructive interference, and electromagnetic ultrasonic longitudinal guided waves which axially propagate at 290kHz are excited in the ferromagnetic pipeline to be measured.
example two
referring to fig. 5, a structural block diagram of a second embodiment of the present invention provides a coil self-excited ferromagnetic pipeline electromagnetic ultrasonic excitation device, including: an electromagnetic ultrasonic transducer 5, a high-power constant current source 6, a pulse signal source 7, an inverter 8, a normal-phase power amplifier 9, an inverse-phase power amplifier 10 and an isolation capacitor 11, wherein,
The electromagnetic ultrasonic transducer 5 is a ferromagnetic pipeline electromagnetic ultrasonic transducer with a coil self-excited provided in the first embodiment, and is installed on a ferromagnetic pipeline 16 to be measured;
The high-power constant current source 6 preferably selects EPS-3020MD constant current source current to generate two paths of 5A direct current bias current; the first output is connected with the positive phase coil group 2 of the electromagnetic ultrasonic transducer 5, and the second output is connected with the reverse phase coil group 3 of the electromagnetic ultrasonic transducer 5.
The pulse signal source 7 preferably functions the arbitrary waveform generator DG832 to generate a sinusoidal pulse signal, the number of pulses taking 5. The output of the pulse signal source 7 is divided into two paths; the first output is connected with the input end of the positive phase power amplifier 9; the second output passes through the inverter 8 and then is connected to the input terminal of the inverting power amplifier 10.
Inverter 8 is preferably a high frequency operational amplifier OPA695 and is connected as an inverting voltage follower.
The isolation capacitor 11 is preferably a non-inductive capacitor of 0.1uF, and is used for isolating the direct current bias current generated by the high-power constant current source 6.
The positive phase power amplifier 9 is preferably a high frequency power amplifier ATA-3080, and the output of the positive phase power amplifier 9 is connected with the positive phase coil group 2 of the electromagnetic ultrasonic transducer 5 after passing through the 0.1uF isolation capacitor 11; the peak current output by the non-inverting power amplifier 9 is 3A.
the inverting power amplifier 10 is preferably another high-frequency power amplifier ATA-3080, and the output of the inverting power amplifier 10 is connected to the inverting coil group 3 of the electromagnetic ultrasonic transducer 5 after passing through the 0.1uF isolation capacitor 11; the peak current output by the inverting power amplifier 10 is 3A.
Since the peak current output by the positive-phase power amplifier 9 and the negative-phase power amplifier 10 is 3A, which is less than 5A of the dc bias current. Therefore, the directions of the magnetization fields generated by the normal-phase coil set 2 and the reverse-phase coil set 3 are constant, and only the magnetization has sinusoidal pulse fluctuations. The sinusoidal pulse fluctuation enables ferromagnetic materials in the pipe wall to generate a periodic magnetostriction effect, and electromagnetic ultrasonic longitudinal guided waves which are transmitted along the axial direction are excited.
EXAMPLE III
Referring to fig. 6, which is a structural block diagram of a third embodiment of the present invention, there is provided a coil self-excited ferromagnetic pipeline electromagnetic ultrasonic receiving apparatus, including: the ultrasonic transducer comprises an electromagnetic ultrasonic transducer 5, a high-power constant current source 6, a coupling capacitor 12, a signal conditioning circuit 13, an acquisition circuit 14 and an upper computer 15, wherein,
The electromagnetic ultrasonic transducer 5 is a ferromagnetic pipeline electromagnetic ultrasonic transducer with a coil self-excited provided in the first embodiment, and is installed on a ferromagnetic pipeline 16 to be measured;
The high-power constant current source 6 preferably selects EPS-3020MD constant current source current to generate two paths of 5A direct current bias current; the first output is connected with the positive phase coil group 2 of the electromagnetic ultrasonic transducer 5, and the second output is connected with the reverse phase coil group 3 of the electromagnetic ultrasonic transducer 5.
the coupling capacitor 12 is preferably a high frequency tile capacitance of 1 nF. The inverter coil group 3 of the electromagnetic ultrasonic transducer 5 is connected with a signal conditioning circuit 13 through a coupling capacitor 12 of 1 nF.
The signal conditioning circuit 13 preferably has a 290kHz bandpass filter and a two-stage linear amplifier with a total gain of 80 dB.
The acquisition circuit 14 is preferably a high-speed data acquisition card USB2815, and the input end of the acquisition circuit 14 is connected with the output end of the signal conditioning circuit 12 and used for converting the electromagnetic ultrasonic signals into digital signals; and the digitized ultrasonic signals are uploaded to the upper computer 15 through a USB data bus for processing.
The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims (5)

1. A coil self-excited ferromagnetic conduit electromagnetic ultrasonic transducer comprising: a framework (1), a normal phase coil group (2) and a reverse phase coil group (3),
the framework (1) is a hollow cylindrical pipe made of insulating materials, the inner diameter of the hollow cylindrical pipe is slightly larger than the outer diameter of the ferromagnetic pipeline to be tested, and the hollow cylindrical pipe is coaxially sleeved on the outer surface of the ferromagnetic pipeline to be tested, 2n annular wire grooves (4) are formed in the upper surface of the framework (1) at equal intervals, the interval between the wire grooves (4) is 1/2 of the wavelength of the excited ultrasonic waves, n is related to the number of the excited electromagnetic ultrasonic pulses and is 3 ~ 10;
the normal phase coil group (2) is formed by connecting n normal phase coils in series, wherein the normal phase coils are annular coils with equal turns and are wound in odd ~ numbered wire slots (4) of the framework (1), and n is 3 ~ 10;
the reverse phase coil group (3) is formed by connecting n reverse phase coils in series, n is 3 ~ 10, the reverse phase coils are annular coils and are wound in wire grooves (4) of the framework (1) in even numbers, the reverse phase coils and the normal phase coils are wound in the same direction, and the number of turns of the reverse phase coils is equal to that of the normal phase coils.
2. a coil self-excited ferromagnetic conduit electromagnetic ultrasonic transducer as claimed in claim 1, wherein the excitation of the positive phase coil set (2) and the negative phase coil set (3) is direct pulse current when used as the excitation end; the direct current pulse current comprises direct current bias current and sine pulse fluctuation, and the amplitude of the sine pulse fluctuation is smaller than the direct current bias current; the direct current bias current acted on the excitation of the positive phase coil group (2) and the direct current bias current acted on the excitation of the reverse phase coil group (3) are in the same direction; and the phase difference between the sine pulse wave phase acted on the excitation of the positive phase coil group (2) and the sine pulse wave phase acted on the excitation of the negative phase coil group (3) is 180 degrees.
3. a coil self-excited ferromagnetic conduit electromagnetic ultrasonic transducer as claimed in claim 1, wherein the excitation of the positive phase coil set (2) and the negative phase coil set (3) is a dc bias current in the same direction when acting as a receiving terminal.
4. A coil self-excited ferromagnetic conduit electromagnetic ultrasonic excitation device, comprising: an electromagnetic ultrasonic transducer (5), a high-power constant current source (6), a pulse signal source (7), an inverter (8), a normal-phase power amplifier (9), an inverse-phase power amplifier (10) and an isolation capacitor,
the electromagnetic ultrasonic transducer (5) is a ferromagnetic pipeline electromagnetic ultrasonic transducer with a self-excited coil as claimed in claim 1, and is mounted on a ferromagnetic pipeline to be tested;
the high-power constant current source (6) generates two paths of direct current bias current outputs with the same size and direction; the first path of output is connected with a normal phase coil group (2) of the electromagnetic ultrasonic transducer (5), and the second path of output is connected with an inverse phase coil group (3) of the electromagnetic ultrasonic transducer (5);
the pulse signal source (7) generates sine pulse signals, the number of pulses of the sine pulse signals is 3 ~ 8, the output of the pulse signal source (7) is divided into two paths, the first path of output is connected with the input end of the positive phase power amplifier (9), and the second path of output is connected with the input end of the reverse phase power amplifier (10) after passing through the phase inverter (8);
The isolation capacitor (11) is an electrodeless capacitor and is used for isolating direct current bias current so as to prevent the output of the high-power constant current source (6) from causing current reverse flow to the positive-phase power amplifier (9) or the reverse-phase power amplifier (10);
The output of the positive phase power amplifier (9) passes through an isolation capacitor (11) and then is connected with a positive phase coil group (2) of the electromagnetic ultrasonic transducer (5); the peak current output by the positive phase power amplifier (9) is less than the direct current bias current of the high-power constant current source (6);
the output of the inverting power amplifier (10) passes through another isolation capacitor (11) and then is connected with an inverting coil group (3) of the electromagnetic ultrasonic transducer (5); the peak current output by the inverting power amplifier (10) is smaller than the direct current bias current of the high-power constant current source (6).
5. a coil self-excited ferromagnetic conduit electromagnetic ultrasound receiving device, comprising: an electromagnetic ultrasonic transducer (5), a high-power constant current source (6), a coupling capacitor (12), a signal conditioning circuit (13), an acquisition circuit (14) and an upper computer (15),
the electromagnetic ultrasonic transducer (5) is a ferromagnetic pipeline electromagnetic ultrasonic transducer with a self-excited coil as claimed in claim 1, and is mounted on a ferromagnetic pipeline to be tested;
The high-power constant current source (6) generates two paths of direct current bias current outputs with the same size and direction; the first path of output is connected with a normal phase coil group (2) of the electromagnetic ultrasonic transducer (5), and the second path of output is connected with an inverse phase coil group (3) of the electromagnetic ultrasonic transducer (5);
The input end of the signal conditioning circuit (13) is connected with the positive phase coil group (2) or the negative phase coil group (3) of the electromagnetic ultrasonic transducer (5) through a coupling capacitor (12) and is used for acquiring electromagnetic ultrasonic signals transmitted in the pipeline;
The input end of the acquisition circuit (14) is connected with the output end of the signal conditioning circuit (13) and is used for converting the electromagnetic ultrasonic signals into digital signals; the output end of the acquisition circuit (14) is connected with an upper computer (15) through a data bus and is used for uploading the digitized ultrasonic signals to the upper computer (15) for processing.
CN201910980409.7A 2019-10-15 2019-10-15 Coil self-excited ferromagnetic pipeline electromagnetic ultrasonic transducer, excitation device and receiving device Pending CN110568060A (en)

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CN111381199A (en) * 2020-03-31 2020-07-07 华中科技大学 Pulse high-intensity magnetic field optical measurement system and method
CN111505121A (en) * 2020-05-22 2020-08-07 西安交通大学 Interpolation type full-coil structure electromagnetic ultrasonic longitudinal guided wave probe and nondestructive testing method
CN112414337A (en) * 2020-12-01 2021-02-26 湖北工业大学 Externally-penetrating annular array electromagnetic ultrasonic thickness measuring probe
US20220236224A1 (en) * 2021-01-25 2022-07-28 Gowell International, Llc Inductive sensor with a magnetic biased coil for eddy current testing

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