WO1999057526A2 - Transducteur ultrasonore - Google Patents

Transducteur ultrasonore Download PDF

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Publication number
WO1999057526A2
WO1999057526A2 PCT/DE1999/001402 DE9901402W WO9957526A2 WO 1999057526 A2 WO1999057526 A2 WO 1999057526A2 DE 9901402 W DE9901402 W DE 9901402W WO 9957526 A2 WO9957526 A2 WO 9957526A2
Authority
WO
WIPO (PCT)
Prior art keywords
ultrasonic transducer
coupling layer
transducer according
coupling
measurement object
Prior art date
Application number
PCT/DE1999/001402
Other languages
German (de)
English (en)
Other versions
WO1999057526A3 (fr
Inventor
Thomas Hahn
Matthias Molitor
Thomas Trautmann
Original Assignee
Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. filed Critical Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority to EP99932668A priority Critical patent/EP1080345A2/fr
Publication of WO1999057526A2 publication Critical patent/WO1999057526A2/fr
Publication of WO1999057526A3 publication Critical patent/WO1999057526A3/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
    • G01F23/296—Acoustic waves
    • G01F23/2968—Transducers specially adapted for acoustic level indicators
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/02—Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators

Definitions

  • the invention relates to an ultrasonic transducer as it can be used, for example, in level measuring devices for measuring the level of a liquid in open or closed containers.
  • This coupling method also fails when there are strong mechanical tensions between the ultrasonic sensor and the test object, for example due to temperature differences, or with undefined test object surfaces.
  • the clamping in connection with the additional application of fat or gel as a coupling agent is very cumbersome.
  • This device for monitoring the liquid level in a container comprises a carrier element, an ultrasonic transducer and a pressing mechanism which is provided in the carrier element and presses the ultrasonic transducer against the container when the carrier element is fastened to the latter.
  • the carrier element is provided with an all-round elastic seal that clings to the surface of the container.
  • a coupling layer made of an auxiliary (silicone gel) must be placed between the membrane of the ultrasonic transducer and the container wall in order to improve the acoustic coupling. As already explained above, this procedure is very cumbersome.
  • US 5 477 729 describes a further ultrasonic transducer arrangement and a coupling technique for coupling the ultrasonic transducer to a measurement object.
  • the arrangement includes a housing, a piezoelectric measuring element and a coupling layer firmly connected thereto, which is connected to a circumferential membrane.
  • the coupling layer is printed against the surface of the measurement object by the restoring force of the membrane.
  • the membrane acts as a pressure element. This ensures defined and constant contact conditions, which are essential for a reliable coupling or measurement.
  • the invention is achieved with the ultrasonic transducer according to claim 1.
  • Advantageous embodiments of the sensor are the subject of the dependent claims.
  • the ultrasonic transducer comprises a piezoelectric disk in a holder.
  • a coupling layer for ultrasound is firmly applied, for example cast on, to the front (radiating) surface of the piezoelectric disk.
  • This coupling layer consists of an elastic material, the elasticity of which allows the coupling layer to nestle against a measurement object surface when the ultrasound transducer is printed against the measurement object surface.
  • the material of the coupling layer should form as smooth a surface as possible. Furthermore, the acoustic impedance of the material must be sufficiently low to still allow measurement at a given thickness. The elasticity must allow the coupling pad to nestle against the surface of the measurement object when a corresponding pressure force is exerted, so that the ultrasonic waves onne large losses or reflections m can be coupled into the measurement object.
  • the coupling layer is preferably made of an elastic polymer (e.g. PU or silicone) with low acoustic impedance, i.e. an acoustic impedance below 4 * 10 ° kg / (m's) (corresponds to 4 MRayl).
  • an elastic polymer e.g. PU or silicone
  • low acoustic impedance i.e. an acoustic impedance below 4 * 10 ° kg / (m's) (corresponds to 4 MRayl).
  • the ultrasound transducer consists, for example, of a piezoceramic disk, which is vaporized on the back by a sound-absorbing potting compound and is provided on the front with the coupling layer (also referred to below as a coupling pad).
  • Unevenness (drops of paint, rust, scratches) on the surface of the measurement object can be compensated for by the elastic properties of the coupling pad m connection with a defined contact pressure of the transducer on the surface.
  • Measuring object surface or a curved shape of the measuring object surface itself This leads to a position-independent coupling possibility.
  • the ultrasonic transducer according to the invention enables an acoustic connection of the transducer to the measurement object wall (dry coupling) that can be released as often as required, without additives or auxiliary substances.
  • dry coupling we also achieve a high abrasion resistance of the transducer surface and thus wear resistance of the transducer.
  • the coupling cushion provides mechanical decoupling against impacts when the transducer is attached to the surface of the measurement object, for example when the container is placed on the transducer, and thus improves its mechanical protection by the shock-absorbing behavior of the elastomer. Since there is no rigid connection between the transducer surface and the measurement object surface, the transducer is suitable for large temperature ranges or high temperature differences between the transducer and measurement object. In a preferred embodiment, the
  • the encapsulation encapsulator fulfills the requirements for explosion protection (possible spark formation inside does not come into contact with the outside atmosphere) and also offers good dust and moisture protection.
  • Figure 1 shows schematically an example of the construction of the converter. The essential feature of the
  • Ultrasonic transducer consists of the permanently elastic coupling layer 1 (coupling cushion) on the radiating surface of the piezoceramic disk 2.
  • the piezoceramic disk 2 is held in a housing 3 which is filled with a sound-absorbing material 4.
  • the electrodes applied to the piezoceramic disk are just as little shown in the figure as the electrical contacting of the transducer. These can be designed in accordance with the prior art and have no influence on the teaching according to the invention.
  • the coupling layer is convex in the figure, the thickness of which in this example is approximately 3 mm in the middle and approximately 2 mm at the edge.
  • ALBIPOL F-1515/3 from Haus Chemie can be used as the material for the coupling layer, which fulfills the material requirements mentioned above.
  • others can also be used as the material for the coupling layer, which fulfills the material requirements mentioned above.
  • PU foam can be used as the full material 4 for the rear vapor deposition.
  • PU with fillers especially made of aluminum oxide, as used in the potting of electronic components, also shows good properties.
  • Converter is the design of the coupling pillow geometry.
  • additional structuring of the surface of the coupling cushion in conjunction with a corresponding contact pressure, a reduction in disturbing surface waves can be achieved.
  • These surface waves preferably arise in thin-walled container walls and prevent accurate echo detection in areas close to the wall.
  • a convex coupling pad surface with concentric, matrix-shaped and / or radial grooves or with individual elevations can be used.
  • the depth of these grooves or elevations is preferably a maximum of about half the maximum thickness of the coupling layer.
  • the thickness of the coupling layer is limited on the one hand by the formation of surface waves, which occur with increasing thickness of the layer, on the other hand by the thickness of the ripple, the surface shape or the unevenness on the surface of the measurement object, which must be compensated for by the coupling layer.
  • the ultrasonic transducer according to the invention advantageously allows an auxiliary material-free, freely exchangeable, acoustic coupling to test objects.

Landscapes

  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Electromagnetism (AREA)
  • Thermal Sciences (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)

Abstract

L'invention concerne un transducteur ultrasonore, tel qu'il peut être utilisé par exemple dans des appareils de mesure de niveau pour mesurer le niveau d'un liquide dans des récipients ouverts ou fermés. Ce transducteur ultrasonore comporte un disque piézoélectrique (2) dans une monture (3). Sur la surface antérieure (rayonnante) du disque piézoélectrique (2), une couche de couplage (1) destinée aux ultrasons est appliquée à demeure, par exemple coulée. Cette couche de couplage (1) est constituée d'un matériau élastique dont l'élasticité lui permet d'épouser la forme de la surface de l'objet à mesurer, lorsque le transducteur ultrasonore est appuyé contre cette surface. Ce transducteur ultrasonore permet de réaliser de manière avantageuse un couplage acoustique avec des objets à mesurer, sans matériel auxiliaire et tout en pouvant être déplacé à volonté.
PCT/DE1999/001402 1998-05-07 1999-05-06 Transducteur ultrasonore WO1999057526A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP99932668A EP1080345A2 (fr) 1998-05-07 1999-05-06 Transducteur ultrasonore

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19820419.1 1998-05-07
DE19820419A DE19820419A1 (de) 1998-05-07 1998-05-07 Ultraschallwandler

Publications (2)

Publication Number Publication Date
WO1999057526A2 true WO1999057526A2 (fr) 1999-11-11
WO1999057526A3 WO1999057526A3 (fr) 2000-03-16

Family

ID=7866974

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1999/001402 WO1999057526A2 (fr) 1998-05-07 1999-05-06 Transducteur ultrasonore

Country Status (3)

Country Link
EP (1) EP1080345A2 (fr)
DE (1) DE19820419A1 (fr)
WO (1) WO1999057526A2 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012209777A1 (de) * 2012-06-12 2013-12-12 Continental Automotive Gmbh Kopplungsvorrichtung und Verfahren zum Herstellen einer Kopplungsvorrichtung
CN115568905A (zh) * 2022-10-17 2023-01-06 深圳迈菲超声医疗器械有限公司 一种超声切削装置

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10344741A1 (de) * 2003-09-25 2005-04-14 Endress + Hauser Gmbh + Co. Kg Schall- oder Ultraschallwandler
US8104341B2 (en) * 2009-03-25 2012-01-31 Schmitt Measurement Systems, Inc. Ultrasonic liquid level monitoring system
DE102012104227A1 (de) * 2012-05-15 2013-11-21 Endress + Hauser Gmbh + Co. Kg Ultraschallwandler
DE102018216624B4 (de) * 2018-09-27 2022-12-08 Vitesco Technologies Germany Gmbh Verfahren und Vorrichtung zum Bestimmen des Füllstands und/oder der Qualität eines Fluids in einem Fluidbehälter

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2934031B1 (de) * 1979-08-02 1980-10-09 Landis & Gyr Ag Ultraschallwandler
US4570482A (en) * 1982-04-23 1986-02-18 Murata Manufacturing Co., Ltd. Load-sensitive level detecting device
US4703652A (en) * 1984-12-01 1987-11-03 Ngk Spark Plug Co., Ltd. Piezoelectric type liquid level sensor and fabricating method thereof
US4780861A (en) * 1984-12-20 1988-10-25 The Coca-Cola Company Automatic control system for filling beverage containers
WO1994004265A1 (fr) * 1992-08-18 1994-03-03 Reson System A/S Transducteur avec membrane de cavitation hautement performante

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07119799B2 (ja) * 1987-08-07 1995-12-20 松下電工株式会社 超音波振動子
CH689125A5 (de) * 1993-09-02 1998-10-15 Kk Holding Ag Schallemissionsaufnehmer.
DE19538696C2 (de) * 1995-10-17 1997-09-25 Endress Hauser Gmbh Co Anordnung zur Überwachung eines vorbestimmten Füllstands einer Flüssigkeit in einem Behälter

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2934031B1 (de) * 1979-08-02 1980-10-09 Landis & Gyr Ag Ultraschallwandler
US4570482A (en) * 1982-04-23 1986-02-18 Murata Manufacturing Co., Ltd. Load-sensitive level detecting device
US4703652A (en) * 1984-12-01 1987-11-03 Ngk Spark Plug Co., Ltd. Piezoelectric type liquid level sensor and fabricating method thereof
US4780861A (en) * 1984-12-20 1988-10-25 The Coca-Cola Company Automatic control system for filling beverage containers
WO1994004265A1 (fr) * 1992-08-18 1994-03-03 Reson System A/S Transducteur avec membrane de cavitation hautement performante

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012209777A1 (de) * 2012-06-12 2013-12-12 Continental Automotive Gmbh Kopplungsvorrichtung und Verfahren zum Herstellen einer Kopplungsvorrichtung
CN115568905A (zh) * 2022-10-17 2023-01-06 深圳迈菲超声医疗器械有限公司 一种超声切削装置

Also Published As

Publication number Publication date
DE19820419A1 (de) 1999-11-18
WO1999057526A3 (fr) 2000-03-16
EP1080345A2 (fr) 2001-03-07

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