EP2223056A1 - Ultrasonic transducer for determining and/or monitoring a flow rate of a measuring medium through a measuring tube - Google Patents
Ultrasonic transducer for determining and/or monitoring a flow rate of a measuring medium through a measuring tubeInfo
- Publication number
- EP2223056A1 EP2223056A1 EP08862073A EP08862073A EP2223056A1 EP 2223056 A1 EP2223056 A1 EP 2223056A1 EP 08862073 A EP08862073 A EP 08862073A EP 08862073 A EP08862073 A EP 08862073A EP 2223056 A1 EP2223056 A1 EP 2223056A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- matching layer
- thickness
- piezoelectric element
- ultrasonic transducer
- coupling element
- 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- Withdrawn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
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
- G01F1/662—Constructional details
Definitions
- Ultrasonic transducer for determining and / or monitoring a flow of a measuring medium through a measuring tube
- the present invention relates to an ultrasonic transducer for determining and / or monitoring a flow of a measuring medium through a measuring tube having at least one piezoelectric element, at least one coupling element and at least one matching layer between the piezoelectric element and the coupling element.
- Ultrasonic flowmeters are widely used in process and automation technology. They allow in a simple way to determine the volume flow in a pipeline without contact,
- the known ultrasonic flowmeters often work after the Doppler or after the transit time difference principle.
- ultrasonic impulses are sent both in and against the flow.
- the runtime difference can be used to determine the flow velocity and, with a known diameter of the pipe section, the volume flow rate.
- the Uitraschallwandler normally consist of a piezoelectric element, also called piezo for short, and a coupling element, Koppeikeil or more rarely
- the adaptation layer assumes the function of the transmission of the ultrasonic signal and at the same time the reduction of a reflection caused by different acoustic impedances at boundary layers between two materials.
- DE2537788A1 and DE3832947A1 describe an adaptation layer made of a plastic which is filled with hollow glass spheres.
- this matching layer has an impedance which lies between the impedance of the piezoelectric element and the impedance of the measuring medium.
- the adaptation layer has a Thickness of a quarter of the characteristic wavelength ⁇ of the ultrasonic signal, which is emitted from the piezoelectric element.
- Coupling element For common impedances of about 30 MRayl for the piezo and about 3 MRayl for the coupling element results in an impedance for the matching layer of 9 to 10 MRayl. Materials used today, such as glass with 11 to 14 MRayl or aluminum with about 17 MRayl are relatively close to the calculated optimum.
- DE4028315A1 discloses a stack of several
- Adaptation layers proposed one above the other.
- the individual layers can have thicknesses smaller than the wall-own wavelength ⁇ w and different
- Damping body attached also called backing, which dampens the vibration on the back of the piezos.
- vibration energy is withdrawn, which thus can not be fed to the measurement.
- the composite of Radiaischwinger and matching layers performs a thickness vibration whose natural resonance is said transducer own wavelength.
- the object of the invention is to propose an ultrasonic transducer for determining and / or monitoring a flow of a measuring medium through a measuring tube with high sensitivity and improved bandwidth.
- an ultrasonic wall sensor for determining and / or monitoring a flow of a measuring medium through a measuring tube which has at least one piezoelectric element, at least one coupling element and at least one matching layer between piezoeiektharim element and coupling element, wherein the matching layer has a thickness less than a quarter of an odd integer has multiples of a wavelength of an ultrasound signal used.
- the thickness of the matching layer is less than one quarter of a wavelength ⁇ of an ultrasonic signal used.
- a damping body on the back of the piezoelectric element is thus not absolutely necessary.
- Both the thicknesses of the individual adaptation layers ⁇ are smaller -, as well as the sum of the thicknesses of the individual layers, so the
- the adhesive layers are conventionally not used for adaptation or regarded as not relevant. According to the invention, adhesive layers also serve as adaptation layers. This happens both in the commonly used materials, e.g. Epoxy resin, as well as specially developed for this purpose potting compounds.
- Epoxy resin e.g. Epoxy resin
- the optimum for the thickness of an adaptation layer surrounded by adhesive shifts due to the presence of the surrounding layers. The effective strength of the adjustment layer is influenced by this.
- the layers are relatively small in wavelength.
- the wavefront emerging from the piezo is assumed to be approximately perpendicular to the matching layers.
- the reflections of the ultrasound and the associated phase jumps no longer take place sharply at the boundaries of the individual layers. Also, by the bonding material properties in the edge regions of the individual layers can be changed.
- the adaptation layer consists of a material which is suitable for casting.
- the material is additionally suitable for frictionally connecting surfaces, ie for gluing them together.
- a single adaptation layer of castable material has, in addition to the manufacturing advantages and the above-mentioned process advantages, above all mechanical advantages.
- Residual stresses during production are low and due to adjustable heat transfer and thermal expansion coefficients are stresses due to temperature-induced expansions.
- the special potting material preferably has an acoustic impedance of less than 15 MRayi, in particular less than 12 MRayl, in particular less than 10 MRayl.
- the acoustic impedance is at least 2 MRay !, in particular at least 5 MRayl, in particular at least 7 MRayl.
- the impedances always depend on the selected piezoelectric element, preferably with 25-35 MRayi, and the coupling element with an impedance of 1-10 MRayl, in particular 2-5 MRayl.
- the matching layer consists of a castable material.
- a further advantageous embodiment of the ultrasonic transducer according to the invention provides that spacers are arranged between the coupling element and the piezoelectric element, which produce a distance of the coupling element to the piezoelectric element, which corresponds to the thickness of the matching layer of the castable material.
- the Uitraschailsensor has three matching layers, wherein the thickness of the first matching layer is smaller than one-fifth of an odd integer multiple of a wavelength of the Uitraschalisignals used, the thickness of the second Matching layer is smaller than a sixth of an odd integer multiple of a wavelength of the ultrasonic signal used and wherein the thickness of the third matching layer is smaller than one fifth of an odd integer multiple of a wavelength of the ultrasonic signal used, wherein the first matching layer consists of a moldable material and the piezoelectric element connects with the second matching layer and wherein the third matching layer is made of a castable material and connects the coupling element with the second matching layer.
- the ultrasonic sensor has three matching layers, the thickness of the first matching layer being less than one fifth of a wavelength of the ultrasound signal used, the thickness of the second matching layer being less than one sixth of a wavelength of the ultrasound signal used and wherein the thickness of the third matching layer is less than one fifth of a wavelength of the ultrasound signal used, wherein the first matching layer is made of a castable material and connects the piezoelectric element to the second matching layer and wherein the third matching layer is made of a castable material and the coupling element with the second adaptation layer connects.
- the thickness of the first and third matching layers is less than one fifth of a wavelength of the ultrasound signal used, in particular less than or approximately equal to one sixth.
- An inventive minimum of the ⁇ first and the third matching layer is - in particular, it is
- the speed of sound in the material used of the two layers is approximately equal and is between 1800 m / s and 2800 m / s, in particular it is about 2300 m / s. At 5 MHz, for example, optimum layer thicknesses of 0.05 to 0.08 mm result.
- the thickness of the second matching layer is less than one sixth of a wavelength of the ultrasound signal used, in particular less than one seventh, preferably it is approximately one-eighth. At least she is - fat, in particular
- a further advantageous development of the ultrasonic wall converter according to the invention consists in that spacers are arranged between the piezoelectric element and the second adaptation layer, which produce a distance between the piezoelectric element and the second adaptation layer, the distance corresponding to the thickness of the first adaptation layer made of the castable material.
- a further advantageous development of the Uitraschallwandlers invention is the fact that between the coupling element and the second adjustment layer spacers are arranged which establish a distance of the coupling element to the second matching layer, wherein the distance of the thickness of the third matching layer of the castable material corresponds.
- the ultrasonic transducer is a thickness oscillator.
- the operating frequency is usually the thickness resonance frequency of the piezoceramic disk, which is determined inter alia by the dimensions of the piezoceramic disk.
- a piezoelectric element referred to as a rocker, thus varies in thickness during transmission.
- the vibratory system which consists inter alia of piezoelectric element and / or matching layer and / or coupling element as Thick vibrator called.
- an ultrasonic transducer works with a piezoceramic, which is excited to radial vibrations, usually in the amount of the radial resonance frequency of the piezo, in the so-called radial mode or in radial mode.
- the piezoelectric element oscillates for at least two oscillation periods.
- the piezoelectric element In contrast to pulsed operation, where a pulse is generated only by a voltage peak discharge, which rapidly fades away, the piezoelectric element emits at least two full waves, i. it is excited to at least two oscillations each of a period or at least one oscillation with two periods. This is preferably done by applying a voltage over a corresponding time to the electrodes of the piezo. This voltage transforms the piezo to equal frequency, i. with the frequency of the applied AC voltage periodic, oscillations. Such successive vibration packets may include several oscillations according to the invention.
- the ultrasonic transducer operates according to the transit time method.
- Fig. 1 shows a schematic sectional view of an inventive
- Ultrasonic transducer with several adaptation layers shows a schematic sectional view of an inventive
- Ultrasonic transducer with an adapter shaft made of castable material.
- an inventive ultrasonic transducer 1 is shown. It comprises a piezoelectric element 2 and a coupling element 3. Between the piezoelectric element 2 and the coupling element 3, three adaptation layers 4 ', 4 ", 4'" are arranged.
- Ultrasonic radiation which corresponds for example to a thickness of about 0.08 mm.
- the middle matching layer 4 "has a thickness of approximately -, for example 0.12 mm.
- the average sound velocity in the matching layer 4 " which consists of a glass or aluminum, is approximately 5600 m / s, whereas in the matching layers 4 'and 4'", for example made of an epoxy resin, average sound velocities of approximately 2300 m / s prevail.
- the adaptation layers 4 'and 4' in addition to the known functions of the adjustment of the ultrasonic signal and the mechanical adjustment additionally take on the task of non-positive connection of piezo 2, Voriauf stresses 3 and fixed matching layer 4".
- FIG. 2 shows an ultrasonic transducer 1 according to the invention with only one matching layer 4 between the piezoelectric element 2 and the coupling element 3.
- the thickness of the matching layer is less ais -, in accordance with the invention
- Matching layer 4 of about 3100 m / s are about 0.12 mm.
- the material of the matching layer 4 is a material that is suitable for casting. In addition, the material is suitable, the opposite surfaces of Piezo 2 and coupling element 3 with each other.
- the potting or the adaptation layer 4 is not made of pure epoxy resin, but it is an adhesive that has embedded particles or particles in which the scarf! can spread very quickly. Hence the speed of sound, compared to the epoxy resin.
- the amazing thing about this arrangement is that despite the theoretically good matching of the impedances by the potted matching layer, which has an acoustic ⁇ impedance of about 8-9 MRayl, its thickness is smaller than - and yet
- the piezo 2 has in this case an acoustic impedance of about 31 MRayi and the coupling element 3 of about 3 MRayl.
- a single matching layer 4 of castable material with a thermal expansion coefficient of about 30 * 10 "6 1 / K, also very well suited to produce a low-tension connection between the piezoelectric element 2 and coupling element 3, which coefficients of expansion of having about 4 * 10 -6 1 / K and 60 * 10 -6 1 / K.
- an adaptation layer of Gia example would have a coefficients of thermal expansion of about ⁇ * 10 "6 1 / K, wherein the adhesive commonly used, such as epoxy resin , Thermal expansion coefficient of about 80 * 10 ⁇ 6 1 / K has.
- the thickness of the matching layer can be determined very accurately by means of the spacers 5. These are, for example, as shown here, attached to the coupling element 3 or are an integral part of the coupling element 3. They have a defined height, which corresponds approximately to the desired thickness of the matching layer. The pourable mass is applied and the piezoelectric element 2 is placed. By a statistically clever distribution of the spacers 5 on the piezo-2 facing surface of the coupling element 3, their influence on the acoustic transmission is low.
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102007060989A DE102007060989A1 (en) | 2007-12-14 | 2007-12-14 | Ultrasonic transducer for determining and / or monitoring a flow of a measuring medium through a measuring tube |
PCT/EP2008/067054 WO2009077377A1 (en) | 2007-12-14 | 2008-12-09 | Ultrasonic transducer for determining and/or monitoring a flow rate of a measuring medium through a measuring tube |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2223056A1 true EP2223056A1 (en) | 2010-09-01 |
Family
ID=40474835
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP08862073A Withdrawn EP2223056A1 (en) | 2007-12-14 | 2008-12-09 | Ultrasonic transducer for determining and/or monitoring a flow rate of a measuring medium through a measuring tube |
Country Status (4)
Country | Link |
---|---|
US (1) | US8689639B2 (en) |
EP (1) | EP2223056A1 (en) |
DE (1) | DE102007060989A1 (en) |
WO (1) | WO2009077377A1 (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102008055123B3 (en) | 2008-12-23 | 2010-07-22 | Robert Bosch Gmbh | Ultrasonic transducer for use in a fluid medium |
US8181534B2 (en) * | 2010-01-06 | 2012-05-22 | Daniel Measurement And Control, Inc. | Ultrasonic flow meter with transducer assembly, and method of manufacturing the same while maintaining the radial position of the piezoelectric element |
DE102012208292A1 (en) * | 2012-05-16 | 2013-11-21 | Robert Bosch Gmbh | A method of making an ultrasonic transducer core with an embedded piezoelectric transducer element |
DE102013111235A1 (en) * | 2012-12-19 | 2014-06-26 | Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG | Arrangement for the optical measurement of one or more physical, chemical and / or biological process variables of a medium |
CN104395704B (en) * | 2013-03-25 | 2017-05-31 | 株式会社又进 | For the ultrasonic sensor and its manufacture method of high temperature |
DE102016119910A1 (en) * | 2016-10-19 | 2018-04-19 | Endress + Hauser Flowtec Ag | Clamp-on ultrasonic sensor for use with an ultrasonic flowmeter and an ultrasonic flowmeter |
DE102017006173A1 (en) * | 2017-06-29 | 2019-01-03 | Diehl Metering Gmbh | Measuring device and method for determining a fluid size |
US11554387B2 (en) | 2019-06-11 | 2023-01-17 | Halliburton Energy Services, Inc. | Ringdown controlled downhole transducer |
WO2021050035A1 (en) | 2019-09-09 | 2021-03-18 | Halliburton Energy Services, Inc. | Acoustic sensor self-induced interference control |
Family Cites Families (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2537788C3 (en) | 1975-08-25 | 1980-04-10 | Siemens Ag, 1000 Berlin Und 8000 Muenchen | Ultrasonic transducer |
FI67627C (en) | 1981-10-19 | 1985-04-10 | Eino Haerkoenen | PROCEDURE FOR THE ORGANIZATION OF THE PROCESSING OF STRUCTURES AND THE EXTENSION OF GENERATION OF THE GENOM UTNYTTJANDET AV ULTRALJUD |
US4598593A (en) | 1984-05-14 | 1986-07-08 | The United States Of America As Represented By The United States Department Of Energy | Acoustic cross-correlation flowmeter for solid-gas flow |
JPS62258597A (en) | 1986-04-25 | 1987-11-11 | Yokogawa Medical Syst Ltd | Ultrasonic transducer |
JPH0778438B2 (en) | 1988-07-08 | 1995-08-23 | エンドレス ウント ハウザー フローテック アクチエンゲゼルシヤフト | Ultrasonic flow rate measuring method and device |
DE3832947C2 (en) | 1988-09-28 | 1996-04-11 | Siemens Ag | Ultrasound transducer |
DE4028315A1 (en) * | 1990-09-06 | 1992-03-12 | Siemens Ag | ULTRASONIC CONVERTER FOR THE RUN TIME MEASUREMENT OF ULTRASONIC IMPULSES IN A GAS |
US5251490A (en) | 1992-02-07 | 1993-10-12 | Kronberg James W | Ultrasonic fluid flow measurement method and apparatus |
EP0686255B1 (en) | 1993-12-23 | 2000-03-15 | Endress + Hauser Flowtec AG | Clamp-on ultrasonic volume flow rate measuring device |
KR20040086503A (en) * | 2002-01-28 | 2004-10-11 | 마츠시타 덴끼 산교 가부시키가이샤 | Acoustic matching layer, ultrasonic transmitter/receiver, and ultrasonic flowmeter |
WO2003064979A1 (en) * | 2002-01-28 | 2003-08-07 | Matsushita Electric Industrial Co., Ltd. | Ultrasonic transmitter-receiver and ultrasonic flowmeter |
EP1575334A1 (en) | 2002-12-20 | 2005-09-14 | Matsushita Electric Industrial Co., Ltd. | Ultrasonic transmitter/receiver, process for producing the same, and ultrasonic flowmeter |
DE102006062706B4 (en) * | 2006-03-30 | 2012-12-06 | Krohne Ag | ultrasonic flowmeter |
US9184369B2 (en) * | 2008-09-18 | 2015-11-10 | Fujifilm Sonosite, Inc. | Methods for manufacturing ultrasound transducers and other components |
US9173047B2 (en) * | 2008-09-18 | 2015-10-27 | Fujifilm Sonosite, Inc. | Methods for manufacturing ultrasound transducers and other components |
EP3576137A1 (en) * | 2008-09-18 | 2019-12-04 | FUJIFILM SonoSite, Inc. | Ultrasound transducers |
DE102008055123B3 (en) * | 2008-12-23 | 2010-07-22 | Robert Bosch Gmbh | Ultrasonic transducer for use in a fluid medium |
-
2007
- 2007-12-14 DE DE102007060989A patent/DE102007060989A1/en not_active Withdrawn
-
2008
- 2008-12-09 EP EP08862073A patent/EP2223056A1/en not_active Withdrawn
- 2008-12-09 US US12/735,040 patent/US8689639B2/en not_active Expired - Fee Related
- 2008-12-09 WO PCT/EP2008/067054 patent/WO2009077377A1/en active Application Filing
Non-Patent Citations (1)
Title |
---|
See references of WO2009077377A1 * |
Also Published As
Publication number | Publication date |
---|---|
US20100257940A1 (en) | 2010-10-14 |
DE102007060989A1 (en) | 2009-06-18 |
US8689639B2 (en) | 2014-04-08 |
WO2009077377A1 (en) | 2009-06-25 |
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Extension state: AL BA MK RS |
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RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: BERGER, ANDREAS Inventor name: BEZDEK, MICHAL Inventor name: WANDELER, FRANK Inventor name: WIEST, ACHIM |
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Effective date: 20170701 |