CN108020155A - A kind of dual coil electromagnetic ultrasonic transducer based on Halbach principles - Google Patents
A kind of dual coil electromagnetic ultrasonic transducer based on Halbach principles Download PDFInfo
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- CN108020155A CN108020155A CN201711366912.0A CN201711366912A CN108020155A CN 108020155 A CN108020155 A CN 108020155A CN 201711366912 A CN201711366912 A CN 201711366912A CN 108020155 A CN108020155 A CN 108020155A
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- permanent magnet
- variable winding
- excitation variable
- coil
- transducer
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/02—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness
- G01B7/06—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness for measuring thickness
- G01B7/10—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness for measuring thickness using magnetic means, e.g. by measuring change of reluctance
Abstract
The present invention relates to a kind of dual coil electromagnetic ultrasonic transducer based on Halbach principles for being used for machine-building and sensor field.It can effectively increase the amplitude that ultrasonic wave receives signal, reduce the generation of noise signal, improve signal-to-noise ratio.Its technical solution is：The electromagnet ultrasonic changer is made of permanent magnet mechanism, coil mechanism, transducer enclosure mechanism, its permanent magnet mechanism includes six array of permanent magnets, permanent magnet shell, array of permanent magnets is installed in permanent magnet shell, and permanent magnet shell is connected with transducer enclosure with fixing screws；Its coil mechanism includes receiving coil, outside excitation variable winding, inner side excitation variable winding, and inner side excitation variable winding is nested in the top that excitation variable winding baffle is installed in the excitation variable winding of outside；Coil mechanism is installed on the following of permanent magnet mechanism, and case lid is connected with transducer upper box lid with lock-screw under transducer.The present invention can effectively improve the amplitude that ultrasonic wave receives signal, and signal-to-noise ratio improves 7 ~ 9 times.
Description
Technical field
The present invention relates to a kind of a kind of twin coil based on Halbach principles for machine-building and sensor field is electric
Magnetic ultrasonic transducer, it is widely used in the thickness measuring of sheet metal.
Background technology
Electromagnet ultrasonic changer (Electro Magnetic Acoustic Transducer, EMAT) is mainly used in
Field, the advantages such as the thickness measuring of steel plate or aluminium sheet, the flaw detection of train wheel track, oil pipeline flaw detection can be achieved on online inspection
Survey, without couplant, be adapted to high temperature and pressure detection environment.Present problems are EMAT small with ultrasonic echo amplitude is received,
The shortcomings that signal-to-noise ratio is low, limits the application of electromagnet ultrasonic changer.Therefore, how to improve the signal-to-noise ratio of transducer be at present urgently
It need to solve the problems, such as
For the improvement of electromagnet ultrasonic changer, domestic and foreign scholars have carried out substantial amounts of research.Document：A kind of electromagnetic acoustic detection
With the development of Pulse excitated power supply（Li Peng, Tsinghua University, 2012）, a kind of power supply of power adjustable section is have devised, passes through tune
Economize on electricity source power adjusts signal-to-noise ratio, and defects detection is carried out on steel plate or steel pipe, but does not refer in aluminium sheet or other non-
Application above ferrimagnet.A kind of development of electromagnetic ultrasonic transducer（Pang Weihan, Beijing Institute of Technology's machinery and vehicle
Institute, 2017）：A kind of electromagnetic ultrasonic transducer is have developed, high-frequency impulse uses UCC3895 as signal source, IR2110 conducts
Full-bridge reciprocal circuit driving chip, by experimental verification, which can be very good the excitation ultrasound ripple on aluminium sheet and can connect
Signal is received, has preferable signal-to-noise ratio, but the device does not refer to the application on ferrimagnet.A New
Electromagnetic Acoustic Transducer Designfor Generating and receiving S0
Lamb Waves in Ferromagnetic Steel Plate（Janpeng He,University of warwick
Conventry CV47AL,UK,2017）：Article describes a kind of new EMAT models, the model only with loop construction and
Traditional permanent magnet excitation is given up, this new structure compared for the effect on Lorentz force mechanism and magnetostriction mechanism
Fruit, have detected aluminium sheet and steel plate respectively, and the results show magnetostriction mechanism improves signal-to-noise ratio.But due to the excitation current of application
Excessive, there are great security risk.An Improved Design of the Spiral-Coil EMAT for
Enhancing the Signal Amplitude（Xiaojuan Jia,Chongqing University,China,2017）:
Article improves the permanent magnet and spiral winding of EMAT.The permanent magnet of cylinder is formed using two parts, i.e., and one
A cylindricality permanent magnet is nested in another magnet ring, and magnetizing direction is opposite.Original single spiral winding is improved to two
Spiral winding, applies the function of current of different directions respectively.By the comparison for emulating and testing, the EMAT sensors finally improved
Signal-to-noise ratio do not improve about before 1.96 times.This signal-to-noise ratio is not applied to, it is necessary to use on serious iron plate of getting rusty
EMAT transducers with bigger signal-to-noise ratio.
The content of the invention
Groundwork of the present invention is to have invented a kind of method and apparatus of the twin coil EMAT based on Halbach principles, it
The amplitude that ultrasonic wave receives signal can effectively be increased, reduce the generation of noise signal, improve signal-to-noise ratio.
The signal-to-noise ratio e of electromagnetic ultrasonic transducer, such as formula（1）It is shown：
（1）
Wherein,It is the voltage signal that receiving coil receives（V）,It is the noise signal that receiving coil receives（V）,It is the power of EMAT（W）, N is the number that rolls of unit length coil, and B is excitation magnetic induction intensity（T）, A is the face of detection range
Product（）,It is the acoustic impedance of ultrasonic wave（）, K is a constant, and T is detection temperature（K）,It is bandwidth（Hz）,It is line
The resistance of circle（）,It is geometrical form factors, h is the lift-off distance between coil and object to be detected（m）, D is coil diameter
（m）.By formula（1）Understand, in the case of keeping other parameters constant, the signal-to-noise ratio of electromagnetic ultrasonic transducer and magnetic induction are strong
Degree it is square directly proportional, therefore, increase excitation magnetic induction density B can improve the signal-to-noise ratio of electromagnetic ultrasonic transducer.
The present invention provides a kind of dual coil electromagnetic ultrasonic transducer based on Halbach principles, the spy of its permanent magnet excitation
Sign is：Using the permanent magnet structure based on Halbach principle arrays, to strengthen sharp magnetic induction density B, which can incite somebody to action
Magnetic field concentration is in side（Strong magnetic side）, and weaken opposite side（Weak magnetic side）Magnetic field,
Pass through theoretical calculation, such as attached drawing（6）Shown, the magnetic field intensity of strong magnetic side is about 3 times of weak magnetic side magnetic field.The permanent magnet
Excitation is further characterized in that：Strong magnetic side based on Halbach principle permanent magnet arrays is located at homonymy with excitation variable winding, common excitation
The generation of ultrasonic wave.
Excitation coil of the present invention is characterized in that：Outside excitation variable winding uses differential " time " type two-wire with inner side excitation variable winding
Coil structures, which is formed by inside and outside two coils in " returning " type nesting, such as attached drawing（5）It is shown, 8 electric current stream of inner side excitation variable winding
To using flowing to clockwise, excitation variable winding 6 current direction in outside is flowed to using counter clockwise direction.Excitation coil coiling shape
Match with the strong magnetic side excitation field distribution shape of Halbach principle permanent magnet arrays.
In order to solve the above-mentioned technical problem, the technical solution adopted by the present invention is：The electromagnet ultrasonic changer is by permanent magnetic
Iron mechanism, coil mechanism, transducer enclosure mechanism composition, such as attached drawing（1）Shown, its top view is attached drawing（2）, the coil plane
Structure is fixedly mounted on below permanent magnet mechanism, and coil mechanism is commonly mounted on transducer enclosure mechanism with permanent magnet mechanism
In.
The coil mechanism includes：Receiving coil baffle 3, receiving coil 4, excitation variable winding baffle 5, outside excitation variable winding 6,
Fixing screws A7, inner side excitation variable winding 8.Wherein, receiving coil 4 is installed on above receiving coil baffle 3, inner side excitation variable winding 8
It is nested in the excitation variable winding 6 of outside, is installed in above excitation variable winding baffle 5, receiving coil baffle 3 and excitation variable winding baffle
5 position is fixed with fixing screws A7 connections.
The permanent magnet mechanism includes：Permanent magnet baffle 9, six array of permanent magnets based on Halbach principles
10（Its mode such as attached drawing that magnetizes（4）It is shown）, permanent magnet shell 11.The array of permanent magnets 10 is fixedly mounted on forever
In magnet shell 11, permanent magnet baffle 9 adjusts permanent magnet mechanism and the distance of coil mechanism, and passes through the fixation of left and right two
Screw 7 realizes the connection of permanent magnet mechanism and coil mechanism, and permanent magnet shell 11 and transducer upper box lid 12 are with fixing
Screw B13 is connected
The transducer enclosure mechanism includes：Case lid 1, lock-screw 2, transducer upper box lid 12, conducting wire 14 under transducer.It is described
Case lid 1 is connected with the lock-screw 2 of transducer upper box lid 12 under transducer, conducting wire 14 from transducer upper box lid 12 pass through with it is outer
Side excitation variable winding 6 is connected with inner side excitation variable winding 8.
The present invention profitable fruit be：The present invention can effectively improve the amplitude that ultrasonic wave receives signal, reduce noise
The generation of signal, signal-to-noise ratio can rise to 7 ~ 9 times of original transducer.
Brief description of the drawings
Fig. 1 is that a kind of dual coil electromagnetic ultrasonic transducer based on Halbach principles of the present invention is a preferred embodiment
Planar structure sectional view；
Fig. 2 is this electromagnet ultrasonic changer top view；
Fig. 3 is the iron plate schematic diagram being detected in this electromagnet ultrasonic changer；
Fig. 4 is the schematic diagram of this electromagnet ultrasonic changer magnet magnetizing direction；
Fig. 5 is the floor map of " returning " type two coil configuration；
Fig. 6 is the magnetic field distribution figure of both sides up and down of array of permanent magnets 10.
The description of symbols of each component in figure：1st, case lid under transducer；2nd, lock-screw；3rd, receiving coil baffle；4th, receive
Coil；5th, excitation variable winding baffle, 6, outside excitation variable winding；7th, fixing screws A；8th, inner side excitation variable winding；9th, permanent magnet baffle；
10th, array of permanent magnets；11st, permanent magnet shell；12nd, transducer upper box lid；13rd, fixing screws B；14th, conducting wire；15th, iron
Plate.
Embodiment
The embodiment of the present invention is as schemed（1）It is shown, including：
A kind of dual coil electromagnetic ultrasonic transducer based on Halbach principles, magnet steel use neodymium of 6 length of sides for the N52 of 10mm
Fe-B permanent magnet linear array, its mode such as attached drawing that magnetizes（4）Shown, strong magnetic side is placed on above iron plate.Coil uses
" returning " type excitation variable winding, in order to match with the Distribution of Magnetic Field of array of permanent magnets 10, its outside area is magnet bottom area
'sTimes, the current direction of inner side excitation variable winding 8 is clockwise, the current direction of outside excitation variable winding 6 is side counterclockwise
To.Detect iron plate 15（Such as figure（3））During thickness, the electric current excitation of outside excitation variable winding 6 and inner side excitation variable winding 8 is by conducting wire 14
It is passed through the three cycle sinusoidal alternating currents that amplitude is 200A and frequency is 2MHz to complete, according to electromagnetic induction principle, is tested iron plate
15 surfaces can induce vortex, which can be subject to alternation under the action of 10 external magnetic field of Halbach array of permanent magnets
Lorentz force acts on, and then promotes the surface microstructure collision of iron plate 15 and produce dither, forms ultrasonic wave and in iron plate 15
Middle propagation, the echo reflected are received by receiving coil 4, so as to complete the detection to 15 thickness of iron plate.
Claims (3)
1. a kind of dual coil electromagnetic ultrasonic transducer based on Halbach principles is by permanent magnet mechanism, coil mechanism and is changed
Energy device shell mechanism composition, it is characterized in that：Coil mechanism is fixedly mounted on below permanent magnet mechanism, coil mechanism and permanent
Magnet mechanism is commonly mounted in transducer enclosure mechanism；The permanent magnet mechanism includes permanent magnet baffle（9）, permanent magnet
Array（10）, permanent magnet shell（11）, array of permanent magnets（10）It is fixedly mounted on permanent magnet shell（11）In, permanent magnetic
Iron shell（11）With transducer enclosure（12）With fixing screws B（13）It is connected；The coil mechanism includes receiving coil baffle
（3）, receiving coil（4）, excitation variable winding baffle（5）, outside excitation variable winding（6）, fixing screws A（7）Inner side excitation variable winding（8）,
Receiving coil（4）Installed in receiving coil baffle（3）Above, inner side excitation variable winding（8）It is nested in outside excitation variable winding（6）Middle peace
Mounted in excitation variable winding baffle（5）Above, receiving coil baffle（3）With excitation variable winding baffle（5）Position fixing screws A
（7）Connection is fixed；The transducer enclosure mechanism includes case lid under transducer（1）, lock-screw（2）, transducer upper box lid
（12）, conducting wire（14）, case lid under its transducer（1）With transducer upper box lid（12）Use lock-screw（2）Connection, conducting wire（14）From
Transducer upper box lid（12）In pass through and shell excitation variable winding（6）With inner side excitation variable winding（8）It is connected.
2. the dual coil electromagnetic ultrasonic transducer according to claim 1 based on Halbach principles, it is characterised in that：Institute
State outside excitation variable winding（6）With inner side excitation variable winding（8）Using differential " time " type two coil configuration, the structure is by inside and outside two lines
Circle is formed in " returning " type nesting, inner side excitation variable winding（8）Current direction is using flow direction clockwise, outside excitation variable winding（6）
Current direction is using counterclockwise flow direction；Excitation variable winding coiling shape and Halbach principle array of permanent magnets（10）It is strong
The excitation field distribution shape matching of magnetic side.
3. the dual coil electromagnetic ultrasonic transducer according to claim 1 based on Halbach principles, it is characterised in that：Institute
State array of permanent magnets（10）Its magnet steel uses neodymium-iron-boron permanent magnet linear array of 6 length of sides for the N52 of 10mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711366912.0A CN108020155A (en) | 2017-12-18 | 2017-12-18 | A kind of dual coil electromagnetic ultrasonic transducer based on Halbach principles |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711366912.0A CN108020155A (en) | 2017-12-18 | 2017-12-18 | A kind of dual coil electromagnetic ultrasonic transducer based on Halbach principles |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN108020155A true CN108020155A (en) | 2018-05-11 |
Family
ID=62073918
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| Application Number | Title | Priority Date | Filing Date |
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| CN201711366912.0A Withdrawn CN108020155A (en) | 2017-12-18 | 2017-12-18 | A kind of dual coil electromagnetic ultrasonic transducer based on Halbach principles |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110496768A (en) * | 2019-09-03 | 2019-11-26 | 厦门大学 | A kind of dual coil electromagnetic ultrasonic transducer for eliminating electromagnetic interference |
| CN112880543A (en) * | 2021-04-12 | 2021-06-01 | 浙江捷安工程有限公司 | Halbach array-based method for measuring diameter of steel bar in cement pole |
| CN117288360A (en) * | 2023-11-24 | 2023-12-26 | 零声科技(苏州)有限公司 | Electromagnetic ultrasonic sensor |
Citations (7)
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|---|---|---|---|---|
| CN2168234Y (en) * | 1993-03-19 | 1994-06-08 | 王新平 | Electromagnetic supersonic thikness-determining instrument |
| JP2009145056A (en) * | 2007-12-11 | 2009-07-02 | Mitsubishi Electric Corp | Electromagnetic ultrasonic probe and electromagnetic ultrasonic flaw detector |
| CN102159944A (en) * | 2008-06-27 | 2011-08-17 | Pii(加拿大)有限公司 | Integrated multi-sensor non-destructive testing |
| CN102175131A (en) * | 2011-02-14 | 2011-09-07 | 厦门大学 | Method for measuring steel plate thickness by leakage magnetic field |
| CN102706966A (en) * | 2012-05-08 | 2012-10-03 | 华中科技大学 | Horizontal-shearing electromagnetic ultrasonic probe |
| CN104767346A (en) * | 2015-04-27 | 2015-07-08 | 重庆大学 | Electromagnetic type vibration energy collector based on Halbach array |
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-
2017
- 2017-12-18 CN CN201711366912.0A patent/CN108020155A/en not_active Withdrawn
Patent Citations (7)
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|---|---|---|---|---|
| CN2168234Y (en) * | 1993-03-19 | 1994-06-08 | 王新平 | Electromagnetic supersonic thikness-determining instrument |
| JP2009145056A (en) * | 2007-12-11 | 2009-07-02 | Mitsubishi Electric Corp | Electromagnetic ultrasonic probe and electromagnetic ultrasonic flaw detector |
| CN102159944A (en) * | 2008-06-27 | 2011-08-17 | Pii(加拿大)有限公司 | Integrated multi-sensor non-destructive testing |
| CN102175131A (en) * | 2011-02-14 | 2011-09-07 | 厦门大学 | Method for measuring steel plate thickness by leakage magnetic field |
| CN102706966A (en) * | 2012-05-08 | 2012-10-03 | 华中科技大学 | Horizontal-shearing electromagnetic ultrasonic probe |
| CN104767346A (en) * | 2015-04-27 | 2015-07-08 | 重庆大学 | Electromagnetic type vibration energy collector based on Halbach array |
| CN105427990A (en) * | 2015-11-23 | 2016-03-23 | 宁波尼兰德磁业有限公司 | NdFeB magnet |
Non-Patent Citations (2)
| Title |
|---|
| XIAOJUAN JIA: "An Improved Design of the Spiral-Coil EMAT for Enhancing the Signal Amplitude" * |
| 唐东林: "基于Halbach原理的电磁超声换能器永磁铁设计" * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110496768A (en) * | 2019-09-03 | 2019-11-26 | 厦门大学 | A kind of dual coil electromagnetic ultrasonic transducer for eliminating electromagnetic interference |
| CN112880543A (en) * | 2021-04-12 | 2021-06-01 | 浙江捷安工程有限公司 | Halbach array-based method for measuring diameter of steel bar in cement pole |
| CN117288360A (en) * | 2023-11-24 | 2023-12-26 | 零声科技(苏州)有限公司 | Electromagnetic ultrasonic sensor |
| CN117288360B (en) * | 2023-11-24 | 2024-02-13 | 零声科技(苏州)有限公司 | Electromagnetic ultrasonic sensor |
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Application publication date: 20180511 |