EP1080345A2 - Ultraschallwandler - Google Patents
UltraschallwandlerInfo
- Publication number
- EP1080345A2 EP1080345A2 EP99932668A EP99932668A EP1080345A2 EP 1080345 A2 EP1080345 A2 EP 1080345A2 EP 99932668 A EP99932668 A EP 99932668A EP 99932668 A EP99932668 A EP 99932668A EP 1080345 A2 EP1080345 A2 EP 1080345A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- ultrasonic transducer
- coupling layer
- transducer according
- coupling
- measurement object
- Prior art date
- Legal status (The legal status 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 status listed.)
- Withdrawn
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
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19820419A DE19820419A1 (de) | 1998-05-07 | 1998-05-07 | Ultraschallwandler |
DE19820419 | 1998-05-07 | ||
PCT/DE1999/001402 WO1999057526A2 (de) | 1998-05-07 | 1999-05-06 | Ultraschallwandler |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1080345A2 true EP1080345A2 (de) | 2001-03-07 |
Family
ID=7866974
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP99932668A Withdrawn EP1080345A2 (de) | 1998-05-07 | 1999-05-06 | Ultraschallwandler |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1080345A2 (de) |
DE (1) | DE19820419A1 (de) |
WO (1) | WO1999057526A2 (de) |
Families Citing this family (6)
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 |
DE102012209777A1 (de) * | 2012-06-12 | 2013-12-12 | Continental Automotive Gmbh | Kopplungsvorrichtung und Verfahren zum Herstellen einer Kopplungsvorrichtung |
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 |
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 |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CH642503A5 (en) * | 1979-08-02 | 1984-04-13 | Landis & Gyr Ag | Ultrasound converter |
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 |
JPH07119799B2 (ja) * | 1987-08-07 | 1995-12-20 | 松下電工株式会社 | 超音波振動子 |
DK102592A (da) * | 1992-08-18 | 1994-02-19 | Reson System As | Transducer med kavitationsmembran |
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 |
-
1998
- 1998-05-07 DE DE19820419A patent/DE19820419A1/de not_active Ceased
-
1999
- 1999-05-06 WO PCT/DE1999/001402 patent/WO1999057526A2/de not_active Application Discontinuation
- 1999-05-06 EP EP99932668A patent/EP1080345A2/de not_active Withdrawn
Non-Patent Citations (1)
Title |
---|
See references of WO9957526A2 * |
Also Published As
Publication number | Publication date |
---|---|
WO1999057526A3 (de) | 2000-03-16 |
WO1999057526A2 (de) | 1999-11-11 |
DE19820419A1 (de) | 1999-11-18 |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
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17P | Request for examination filed |
Effective date: 20000922 |
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17Q | First examination report despatched |
Effective date: 20010712 |
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STAA | Information on the status of an ep patent application or granted ep patent |
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Effective date: 20020108 |