CN106694346A - Low-noise transmitting and receiving integrated electromagnetic acoustic transducer and working method thereof - Google Patents
Low-noise transmitting and receiving integrated electromagnetic acoustic transducer and working method thereof Download PDFInfo
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- CN106694346A CN106694346A CN201611237906.0A CN201611237906A CN106694346A CN 106694346 A CN106694346 A CN 106694346A CN 201611237906 A CN201611237906 A CN 201611237906A CN 106694346 A CN106694346 A CN 106694346A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
- B06B1/04—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with electromagnetism
- B06B1/045—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with electromagnetism using vibrating magnet, armature or coil system
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating 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
- G01N29/34—Generating the ultrasonic, sonic or infrasonic waves, e.g. electronic circuits specially adapted therefor
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- Life Sciences & Earth Sciences (AREA)
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- Mechanical Engineering (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
Abstract
The invention discloses a low-noise transmitting and receiving integrated electromagnetic acoustic transducer and a working method of the low-noise transmitting and receiving integrated electromagnetic acoustic transducer. The transducer is composed of a test piece, a printed circuit board, transmitting coils, a permanent magnet and receiving coils. The transmitting coils and the receiving coils are alternately arranged on different layers of the same printing circuit board. The permanent magnet is arranged on the transmitting coils and the receiving coils. The transmitting coils and the receiving coils share the same permanent magnet to provide a bias magnetic field. The transmitting coils and the receiving coils are put on the test piece. The transmitting coils are connected with a power amplifier. The receiving coils are connected with a signal conditioning circuit. According to the low-noise transmitting and receiving integrated electromagnetic acoustic transducer and the working method, by changing the transducer coil structure form, the length of coil wires is increased, the shape of the adjacent semi-wavelength wire inflection portions of the coils is changed, the eddy current generated by the inflection portions of the coil side faces is not affected by the static bias magnetic field of the permanent magnet, the ultrasound noise jamming generated by the side face coils is lowered, and the signal-to-noise ratio is increased.
Description
Technical field：
The present invention relates to electromagnetic ultrasonic non-destructive detection technique, the transceiver electromagnetic acoustic transducing of specially a kind of low noise
Device and its method of work.
Background technology：
Electromagnet ultrasonic changer (Electromagnetic acoustic transducer, abbreviation EMAT) is a kind of sharp
The device of hair and reception ultrasonic wave.The device can easily excite the ultrasound of various modes without acoustic couplant, simple structure
Ripple, is capable of achieving non-cpntact measurement, therefore is extensively paid close attention to by researcher.Electromagnet ultrasonic changer is mainly made up of 3 parts：Launch, connect
Take-up circle, magnet and test specimen to be measured.Because the conversion efficiency of electromagnet ultrasonic changer is than relatively low, the ultrasonic signal for inspiring is extremely
It is faint, cause the signal to noise ratio of the signal for receiving relatively low, easily it is interfered, cause to be also easy to produce erroneous judgement during measurement, interference is believed
Number as flaw indication.Inflection coil is widely used exciting and receiving coil as ultrasonic transducer, in manufacturing process,
All it is to use right angle cabling between the winding wire of adjacent one-half wavelength distance, and right angle cabling can become the line width of transmission line
Change, cause the discontinuous of impedance, right angle cabling there are three influences of aspect to signal：One is that turning can be equivalent to transmission line
On capacitive load, slow down the rise time；Two is the reflection that impedance discontinuity can cause signal；Three is that right angle tip produces
EMI so that the current vortex skewness produced on test specimen to be measured, so as to cause intensity distribution during ultrasonic excitation uneven, shadow
Ring Detection results.On the other hand, existing use inflection coil as excitation coil electromagnet ultrasonic changer, the length of magnet and
Width is all higher than the length and width of coil, due to the length of the length more than wire of magnet so that inflection coil is separated by half-wave
Connecting wire between the wire of long range also causes generation ultrasonic wave in test specimen to be measured, when transducer is both also served as transmitting
This part of ultrasonic signal will be included during reception, in the signal for receiving, this part signal just becomes our institutes not
Desired noise, when for measuring width less test specimen, the influence of this noise is particularly evident.
The content of the invention：
It is an object of the invention to provide a kind of single magnet, transceiver and receive and transmitting coil is discrete is applied to
The electromagnet ultrasonic changer of narrow boards detection, is reduced because the ultrasonic signal noise that side coil is produced influences on measurement result.
The present invention is adopted the following technical scheme that：A kind of transceiver electromagnet ultrasonic changer of low noise, by test specimen to be measured,
Printed circuit board, transmitting coil, permanent magnet and receiving coil are constituted, and the transmitting coil is arranged on same print with receiving coil
On the different layers of circuit board processed and different layers are disposed alternately at, permanent magnet is placed on above transmitting coil and receiving coil, institute
State transmitting coil and receiving coil shares a block permanent magnet to provide bias magnetic field, transmitting coil and receiving coil are placed on to be checked
On test block, transmitting coil is connected with external power amplifier, for producing ultrasonic wave inside test specimen to be measured, receiving coil with
External signal modulate circuit is connected, for detecting the ultrasonic vibration in test specimen to be measured.
Further, the transmitting coil is more than the length L1 of permanent magnet with the length L2 of receiving coil.
Further, the transmitting coil is more than 1.2 times of the length L1 of permanent magnet with the length L2 of receiving coil.
Further, the spacing distance in the transmitting coil between wire is the half-wavelength of the ultrasonic wave to be excited.
Further, the area of each cross section of wire is the same in the transmitting coil.
Further, the area of each cross section of wire is the same in the receiving coil.
Further, the transmitting coil and the receiving coil reverse between adjacent wire of half-wavelength are circular arc.
The present invention is also adopted the following technical scheme that：A kind of work of the transceiver electromagnet ultrasonic changer of low noise, bag
Include following steps：
Step one：Burst pumping signal, pumping signal are produced by being connected the signal generator being connected with power amplifier
After-applied onto transmitting coil through power amplification, transmitting coil induces current vortex on test specimen to be measured, and current vortex is in permanent magnet
Lorentz force is produced under the quiescent biasing magnetic fields of generation in test specimen to be measured, dynamic Lorentz forces are acted in test specimen to be measured
Produce ultrasonic wave；
Step 2：Ultrasonic wave is propagated in test specimen to be measured, runs into defect or border back reflection echo-signal, when echo warp
When crossing receiving coil lower section, the Particles Moving cutting permanent magnet inside test specimen to be measured produces the magnetic line of force and produces electric current to form dynamic
Electric field, dynamic electric field produces dynamic magnetic field, receiving coil to produce dynamic current signal, dynamic electric under dynamic magnetic field effect again
Flow through after signal conditioning circuit is nursed one's health for detecting the ultrasonic vibration in test specimen to be measured.
The present invention has the advantages that：The transceiver electromagnet ultrasonic changer of low noise of the present invention, by changing
The structure type of transducer winding, can reach following effect：Increase excitation variable winding conductor length so that the inflection of coil side
Current vortex produced by part reduces the quiescent biasing magnetic field influence of permanent magnet, so as to reduce due to the ultrasound that side coil is produced
Noise jamming, improves signal to noise ratio；By transmitting coil and receiving coil design on same PCB, transmitting coil and receiving coil
Wire overlap and alternately arrange on different layers, be capable of achieving transmitting and receive to share same permanent magnet biasing magnetic is provided
, during transmitting coil transmission signal, receiving coil can just sense pumping signal, record the time of ultrasonic wave transmitting, it is to avoid
In the case of sharing a coil transmissions and receiving ultrasonic wave, first transmitting coil is connected to excitation power supply transmission signal, launched
Coil is switched in receiving circuit by switching switch again after complete signal, using original transmitting coil as receiving coil, institute
The reception signal for bringing brings time delay to miss in time scale in time domain without reference to the launch time point of point, and circuit switching
Poor problem；Transmitting coil and receiving coil use arc structure at the inflection between the wire of interval half wavelength so that hair
Ray circle and receiving coil conductor cross-section area are consistent, and impedance is continuous, reduce the noise that electromagnetic interference is brought.
Brief description of the drawings：
Fig. 1 is the profile of electromagnet ultrasonic changer of the present invention.
Fig. 2 (a), Fig. 2 (b) are the length and permanent magnet length vs figure of transmitting coil and receiving coil.
Fig. 3 (a), Fig. 3 (b) compare figure for conventional coil with loop construction of the present invention.
Specific embodiment：
The present invention will be further described below in conjunction with the accompanying drawings.
The transceiver electromagnet ultrasonic changer of low noise of the present invention is by test specimen to be measured 1, printed circuit board (PCB) 2, transmitting
Coil 3, permanent magnet 4 and receiving coil 5 are constituted, and transmitting coil 3 is arranged on same multilayer printed circuit board 2 with receiving coil 5
Different layers on and be disposed alternately at different layers, permanent magnet 4 is placed on above transmitting coil 3 and receiving coil 5, transmitting coil
3 and receiving coil 5 share a block permanent magnet 4 and bias magnetic field be provided, transmitting coil 3 and receiving coil 5 be placed on test to be checked
On part 1, transmitting coil 3 is connected with external power amplifier, for producing ultrasonic wave inside test specimen to be measured 1, receiving coil 5 with
External signal modulate circuit is connected, for detecting the ultrasonic vibration in test specimen to be measured 1.
Transmitting coil 3 is arranged on the different layers of same multilayer printed circuit board 2 and is disposed alternately at receiving coil 5
Different layers, transmitting coil 3 works independently with receiving coil 5, and same transducer can both launch ultrasonic wave, it is also possible to receive
Ultrasonic wave, it is to avoid one-coil transducer not only as transmitting coil but also as receiving coil used time complicated control switching circuit,
Reduce circuit and switch the brought time difference.Transmitting coil 3 is more than the length L1 of permanent magnet 4, and hair with the length L2 of receiving coil 5
Ray circle 3 is more than 1.2 times of the length L1 of permanent magnet 4 with the length L2 of receiving coil 5, i.e., wire inflection side is in permanent magnet 4
Outward, permanent magnet 4 is placed on the middle part of wire, when exciting current is by transmitting coil 3 and receiving coil 5, emission lines
The current vortex of circle 3 and receiving coil 5 between the wire of half-wavelength of interval produced by reverse wire is by the quiet of permanent magnet generation
The effect of state bias magnetic field and produce ultrasonic hash.
It is the half-wavelength of ultrasonic wave that transmitting coil 3 is used to producing the spacing distance between the wire of ultrasonic wave, and wire it
Between use at inflection with the prismatic circular sliding slopes of conductor width, the area of each cross section of wire is the same, sectional area of wire
Uniformity, it is to avoid the right angle turns that are connected by a distance of between wire of half-wavelength cause sectional area of wire to change and cause wire to hinder
Anti- change, while the electromagnetic interference that the charge concentration for eliminating inflection sharp corner causes, reduces noise.
During detection, pumping signal of bursting is produced by signal generator, pumping signal is after-applied to emission lines through power amplification
On circle 3, transmitting coil 3 induces current vortex on test specimen to be measured 1, and current vortex is made in the quiescent biasing magnetic field that permanent magnet 4 is produced
Lorentz force, dynamic Lorentz forces is produced to produce ultrasonic wave in acting on test specimen to be measured 1 in test specimen to be measured 1 under；Ultrasonic wave
Propagated in test specimen to be measured 1, run into defect or border back reflection echo-signal, it is to be measured when echo is by transducer lower section
Particles Moving inside test specimen 1 cuts the magnetic line of force of the generation of permanent magnet 4 and produces electric current to form dynamic electric field, and dynamic electric field is again
Dynamic magnetic field, receiving coil 5 is produced to produce dynamic current signal under dynamic magnetic field effect, dynamic current is through signal conditioning circuit
As the foundation of detection after conditioning.Shown in Fig. 2, the transmitting coil 3 of electromagnet ultrasonic changer and the length L2 of receiving coil 5 are forever
More than 1.2 times of the length L1 of magnet 4, wire inflection side outside permanent magnet 4, so as to avoid wire inflection side in quiescent biasing magnetic field
Effect is lower to produce useless interference noise.Fig. 3 (a) is traditional coil, is to use straight line at its inflection, and point can be produced at inflection
Angle, interfacial area of the wire at inflection becomes big, conductor impedance change, and sharp corner produces charge buildup；3 (b) is institute of the present invention
The coil of design, the traverse design at inflection is into semicircle arcuation, and sectional area of the wire at inflection is constant, each cross section of wire
Impedance is consistent, so as to reduce the reflection of signal.Due to without the wedge angle at inflection, therefore avoid being led due to electric charge kelvin effect
The electromagnetic interference that lotus gathers and causes in sharp corner is sent a telegraph, so as to improve the signal to noise ratio of electromagnet ultrasonic changer.
The above is only the preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art
For member, some improvement can also be made under the premise without departing from the principles of the invention, these improvement also should be regarded as of the invention
Protection domain.
Claims (8)
1. the transceiver electromagnet ultrasonic changer of a kind of low noise, it is characterised in that：By test specimen to be measured (1), printed circuit board
(2), transmitting coil (3), permanent magnet (4) and receiving coil (5) are constituted, and the transmitting coil (3) is arranged on receiving coil (5)
On the different layers of same printed circuit board (2) and different layers are disposed alternately at, permanent magnet (4) is placed on transmitting coil (3)
With receiving coil (5) above, the transmitting coil (3) and receiving coil (5) share a block permanent magnet (4) to provide biasing magnetic
, transmitting coil (3) and receiving coil (5) be placed on test block to be checked (1), transmitting coil (3) and external power amplifier
Connection, for producing ultrasonic wave inside test specimen to be measured (1), receiving coil (5) is connected with external signal modulate circuit, for examining
The ultrasonic vibration surveyed in test specimen to be measured (1).
2. the transceiver electromagnet ultrasonic changer of low noise as claimed in claim 1, it is characterised in that：The transmitting coil
(3) with the length L1s of the length L2 more than permanent magnet (4) of receiving coil (5).
3. the transceiver electromagnet ultrasonic changer of low noise as claimed in claim 2, it is characterised in that：The transmitting coil
(3) with the length L2 of receiving coil (5) it is more than 1.2 times of length L1 of permanent magnet (4).
4. the transceiver electromagnet ultrasonic changer of low noise as claimed in claim 3, it is characterised in that：The transmitting coil
(3) spacing distance between wire is the half-wavelength of the ultrasonic wave to be excited.
5. the transceiver electromagnet ultrasonic changer of low noise as claimed in claim 4, it is characterised in that：The transmitting coil
(3) area of each cross section of wire is the same in.
6. the transceiver electromagnet ultrasonic changer of low noise as claimed in claim 5, it is characterised in that：The receiving coil
(5) area of each cross section of wire is the same in.
7. the transceiver electromagnet ultrasonic changer of the low noise as described in claim 5 or 6, it is characterised in that：The hair
Ray circle (3) and receiving coil (5) reverse between adjacent wire of half-wavelength are circular arc.
8. the method for work of the transceiver electromagnet ultrasonic changer of a kind of low noise, it is characterised in that：Comprise the following steps
Step one：Pumping signal of bursting is produced by being connected the signal generator being connected with power amplifier, pumping signal is through work(
Rate amplifies after-applied onto transmitting coil (3), and transmitting coil (3) induces current vortex on test specimen to be measured (1), and current vortex is forever
Lorentz force is produced under the quiescent biasing magnetic fields that magnet (4) is produced in test specimen to be measured (1), dynamic Lorentz forces are acted on
Ultrasonic wave is produced in test specimen (1) to be measured；
Step 2：Ultrasonic wave is propagated in test specimen to be measured (1), runs into defect or border back reflection echo-signal, when echo warp
When crossing receiving coil (5) lower section, the internal Particles Moving of test specimen (1) to be measured cuts permanent magnet (4) and produces the magnetic line of force and produce electricity
Stream forms dynamic electric field, and dynamic electric field produces dynamic magnetic field, receiving coil (5) to produce dynamic electric under dynamic magnetic field effect again
Stream signal, dynamic current is used for detecting the ultrasonic vibration in test specimen to be measured (1) after being nursed one's health through signal conditioning circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611237906.0A CN106694346B (en) | 2016-12-28 | 2016-12-28 | Low-noise transmitting-receiving integrated electromagnetic ultrasonic transducer and working method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611237906.0A CN106694346B (en) | 2016-12-28 | 2016-12-28 | Low-noise transmitting-receiving integrated electromagnetic ultrasonic transducer and working method thereof |
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| Publication Number | Publication Date |
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| CN106694346A true CN106694346A (en) | 2017-05-24 |
| CN106694346B CN106694346B (en) | 2022-08-05 |
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| CN201611237906.0A Active CN106694346B (en) | 2016-12-28 | 2016-12-28 | Low-noise transmitting-receiving integrated electromagnetic ultrasonic transducer and working method thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107084692A (en) * | 2017-06-30 | 2017-08-22 | 沈阳工业大学 | Electromagnetic acoustic shear wave thickness measuring transducer |
| CN107727742A (en) * | 2017-10-11 | 2018-02-23 | 哈尔滨工业大学 | A kind of electromagnetic acoustic phased array system |
| CN110043810A (en) * | 2019-05-23 | 2019-07-23 | 山东省科学院激光研究所 | Detection method, the packaging method of sensor and sensor of defect of pipeline |
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|---|---|---|---|---|
| US6038925A (en) * | 1997-03-21 | 2000-03-21 | Ebara Corporation | Focal type electromagnetic acoustic transducer and flaw detection system and method |
| US20060278000A1 (en) * | 2003-06-19 | 2006-12-14 | Pii Ltd | Electromagnetic acoustic transducer |
| US20100244591A1 (en) * | 2009-03-30 | 2010-09-30 | Korea Research Institute Of Standards And Science | Method and apparatus for monitoring wall thinning of a pipe using magnetostrictive transducers and variation of dispersion characteristics of broadband multimode shear horizontal (SH) waves |
| US20120014222A1 (en) * | 2010-07-15 | 2012-01-19 | Frank Niese | Electromagnetic ultrasound transducer |
| CN206373042U (en) * | 2016-12-28 | 2017-08-04 | 南京航空航天大学 | A kind of transceiver electromagnet ultrasonic changer of low noise |
-
2016
- 2016-12-28 CN CN201611237906.0A patent/CN106694346B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6038925A (en) * | 1997-03-21 | 2000-03-21 | Ebara Corporation | Focal type electromagnetic acoustic transducer and flaw detection system and method |
| US20060278000A1 (en) * | 2003-06-19 | 2006-12-14 | Pii Ltd | Electromagnetic acoustic transducer |
| US20100244591A1 (en) * | 2009-03-30 | 2010-09-30 | Korea Research Institute Of Standards And Science | Method and apparatus for monitoring wall thinning of a pipe using magnetostrictive transducers and variation of dispersion characteristics of broadband multimode shear horizontal (SH) waves |
| US20120014222A1 (en) * | 2010-07-15 | 2012-01-19 | Frank Niese | Electromagnetic ultrasound transducer |
| CN206373042U (en) * | 2016-12-28 | 2017-08-04 | 南京航空航天大学 | A kind of transceiver electromagnet ultrasonic changer of low noise |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107084692A (en) * | 2017-06-30 | 2017-08-22 | 沈阳工业大学 | Electromagnetic acoustic shear wave thickness measuring transducer |
| CN107727742A (en) * | 2017-10-11 | 2018-02-23 | 哈尔滨工业大学 | A kind of electromagnetic acoustic phased array system |
| CN110043810A (en) * | 2019-05-23 | 2019-07-23 | 山东省科学院激光研究所 | Detection method, the packaging method of sensor and sensor of defect of pipeline |
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| CN106694346B (en) | 2022-08-05 |
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