EP0340624B1 - Transducteur électro-acoustique - Google Patents

Transducteur électro-acoustique Download PDF

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Publication number
EP0340624B1
EP0340624B1 EP89107599A EP89107599A EP0340624B1 EP 0340624 B1 EP0340624 B1 EP 0340624B1 EP 89107599 A EP89107599 A EP 89107599A EP 89107599 A EP89107599 A EP 89107599A EP 0340624 B1 EP0340624 B1 EP 0340624B1
Authority
EP
European Patent Office
Prior art keywords
housing
transducer
face
accordance
flange
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.)
Expired - Lifetime
Application number
EP89107599A
Other languages
German (de)
English (en)
Other versions
EP0340624A3 (fr
EP0340624A2 (fr
Inventor
Dieter Stutzke
Ernst Dipl.-Ing. Eckstein
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hontzsch GmbH
Original Assignee
Hontzsch GmbH
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 Hontzsch GmbH filed Critical Hontzsch GmbH
Publication of EP0340624A2 publication Critical patent/EP0340624A2/fr
Publication of EP0340624A3 publication Critical patent/EP0340624A3/fr
Application granted granted Critical
Publication of EP0340624B1 publication Critical patent/EP0340624B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
    • B06B1/0644—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element
    • B06B1/0662—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element with an electrode on the sensitive surface
    • B06B1/0674—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element with an electrode on the sensitive surface and a low impedance backing, e.g. air
    • 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
    • G10K11/004—Mounting transducers, e.g. provided with mechanical moving or orienting device

Definitions

  • the invention relates to an electroacoustic transducer for use as a sound transmitter and / or sound receiver for sound fields in gaseous media with an electrostrictive or piezoelectric body, which is arranged in a housing that at least partially surrounds the body in a ring and is provided with electrodes that are used to tap an acoustic Vibrations occurring in the body alternating electrical voltage or to act upon the body with a structure-borne vibrating electrical alternating voltage.
  • a piezoceramic body is attached to an epoxy resin film which is arranged on the end face of a tubular housing. If the gaseous media contain dust or other abrasive substances, the epoxy resin film, which is arranged on the front side of the housing facing the sound field, can be removed relatively quickly. This destroys the electroacoustic transducer.
  • an electroacoustic transducer with a closed housing is known, a piezoelectric body or the like. attached to one end of the housing and otherwise embedded in a vibration-damping material which fills the interior of the housing.
  • the housing is through one Ring area made of vibration-damping adhesive divided.
  • the housing can be damaged relatively easily by abrasive particles in the area of the subdivision, only comparatively low efficiencies can be achieved with this known construction because the like of the piezoelectric body or the like. generated vibrations of one housing end face are weakened by the adhesive layer mentioned on the housing subdivision and by the vibration-damping material in the housing.
  • the object of the invention is now to provide an electroacoustic transducer which can work trouble-free in heavily contaminated gaseous media on the one hand and on the other hand has a good efficiency.
  • the housing has a closed sound-radiating or sound-receiving end face, and in that the body is arranged firmly on this end face, but with mobility relative to the ring-shaped part of the housing enclosing the body, between the body and the same enclosing housing part remains an annular space as a clearance zone or air gap.
  • the invention is based on the finding that structure-borne sound vibrations can be transmitted practically loss-free between the end face and the piezoelectric body if the coupling between the end face and the piezoelectric body is harder. At the same time is achieved by the mobility of the piezoelectric body relative to the housing part surrounding it that the Piezoelectric body generated vibrations are radiated from the end face into the gaseous medium or the vibrations impinging on the end face from the sound field are effectively transmitted to the piezoelectric body.
  • the housing wall can vibrate largely undisturbed. Moreover, only negligible sound reflections occur at the interfaces between the piezoelectric body and the housing, because the densities of the body material, generally a ceramic, and of the material from which the housing is made can have similar values.
  • the potting compound or connection layer used to fasten the piezoelectric body to the end face of the housing should on the one hand be sufficiently hard for an effective transmission of mechanical vibrations or sound waves between the piezoelectric body and the end face and on the other hand be so soft that the intensity of the vibrations or Sound waves have a pronounced main maximum at a resonance frequency and, where appropriate, secondary maxima occurring in other, in particular adjacent frequency ranges, are comparatively weak. It depends the optimal hardness of the sealing compound or connection layer also depends on the layer thickness.
  • the suppression of the secondary maxima is desirable because this means that the electronic outlay for a driver circuit to excite the mechanical vibrations or sound waves in the piezoelectric body or an evaluation circuit for processing the electrical voltage that can be tapped at the piezoelectric body, the amplitude of which corresponds to the mechanical excitation in the piezoelectric body Vibrations or sound waves is changed, is significantly reduced.
  • the desired hardness of the casting compound or compound layer or the like can be added by adding quartz powder. can be set.
  • the housing is removed from its end face with the interposition of flexible material that counteracts the transmission of mechanical vibrations or sound waves, such as e.g. Silicone, to hold.
  • the single figure shows a flow meter with electroacoustic transducers according to the invention.
  • a for example cuboid, essentially solid metal or support body 1 is penetrated by a channel 2 through which a part of a gaseous medium flows.
  • a rod-like interfering body 3 Arranged within the channel 2 is, for example, a rod-like interfering body 3, which produces vortices due to the flow of the gaseous medium.
  • Electroacoustic transducers 4 and 5 are arranged on two opposite sides of the channel 2, one of which works as a sound transmitter and the other as a sound receiver.
  • the transducers 4 and 5 are arranged in such a way that the sound field generated passes through the region of the vortices generated by the disturbing body 3 in the gas flow.
  • the sound waves generated by the transducer 4 are scattered to a greater or lesser extent, so that, depending on the flow velocity of the gaseous medium, sound with different intensity is applied to the transducer 5 working as a receiver hits.
  • the transducers 4 and 5 have the same structure and are arranged in principle in the same way on the metal or support body 1.
  • transverse bores 7 are arranged on the metal or support body 1 on parts opposite one another with respect to the channel 2 and extend from the outside of the metal or support body 1 to the channel 2.
  • the transducers 4 and 5 each have a substantially cylindrical housing 8 which faces the channel 2 with a closed end 8 '. At the opposite open end of the housing 8, a flange 8 ⁇ is arranged. Between flange 8 ⁇ and end face 8 'has in comparison to the end face 8' thick peripheral wall of the housing 8 an area of small wall thickness 8 ′′′. For this purpose, an annular groove open to the outside is formed in the peripheral wall.
  • the diameter of the housing 8 is slightly smaller than the diameter of the bore 7. Accordingly, an annular gap remains between the wall of the bore 7 and the outer circumference of the housing 8.
  • the flange 8 ' is accommodated in a step-widened area of the bore 7 without direct contact with the metal or support body 1.
  • a soft casting compound which forms a flange 8 Flansch holding intermediate layer 9, which also has the task of transferring structure-borne noise between the housing 8 or the flange 8 ⁇ and the metal or Prevent supporting body 1. At the same time, this prevents mechanical vibrations or sound waves generated by the transducer 4 from reaching the transducer 5 directly via the metal or supporting body 1 without passing through the channel 2 or the gas flow in the channel 2.
  • a piezoceramic body 10 is accommodated, which is provided on opposite end faces with electrodes 11, which can consist, for example, of vapor-deposited or baked metal layers. If an electrical alternating voltage is applied to the electrodes 11, mechanical vibrations or sound waves are excited due to the piezoelectric effect in the body 10. In reverse accordingly In this way, mechanical vibrations or sound waves in the piezoelectric body 10 generate an electrical alternating voltage that can be picked up at the electrodes 11.
  • the electrodes 11 or the like are not shown via cables. connected to electronic circuits, not shown, for applying an alternating electrical voltage to the electrodes 11 or for processing the alternating electrical voltage that can be tapped at the electrodes 11.
  • the piezoceramic body 10 is fastened to the inside of the closed end face 8 'of the housing 8 with the aid of a relatively hard casting compound which forms a thin connecting layer 12.
  • Epoxy resin is particularly suitable as material for the connecting layer 12, which may contain a high volume fraction, e.g. more than 50 vol. %, can be mixed with quartz powder to ensure a desired hardness of the connecting layer 12.
  • the connecting layer 12 must be sufficiently hard to ensure good transmission of mechanical vibrations or sound waves between the end face 8 'of the housing 8 and the piezoceramic body 10. On the other hand, however, the connecting layer 12 must still be so soft that the intensity of the vibrations or sound waves at a resonance frequency has a clear main maximum and any secondary maxima which may occur are only slightly pronounced in other, in particular adjacent, frequency ranges. The secondary maxima should therefore be avoided or suppressed as much as possible, since this considerably reduces the electronic outlay for the circuits connected to the piezoceramic body 10.
  • the piezoceramic body 10 is dimensioned such that an annular space remains free between the outer surface of the body 10 and the cylindrical part of the housing 8, which allows unimpeded relative movement between the cylindrical housing part and the piezoceramic body 10. If necessary, the piezoceramic body 10 can be weighted or connected to an inert mass at its end facing away from the end face 8 'of the housing 8. For example, it is possible to connect said end of the piezoceramic body 10 to a cover or potting compound 14 that closes the open housing side.
  • the transducers 4 and 5 are generally completely identical. In the drawing, however, some details deviating from the converter 4 are shown on the converter 5.
  • the flange 8 ⁇ of the transducer 5 is held between two elastic O-rings 15 and 16, which are supported on the ring step of the bore 7 or on a pressure ring or a pressure plate 17, which are arranged on or in the expanded region of the bore 7 is.
  • the O-ring 15 also serves as a seal for the enlarged area of the bore 7 from the medium in the channel 2.
  • the flange 8 ⁇ can be subjected to bending if the O-rings 15 and 16 are clamped with appropriate pressure between the flange 8 ⁇ and the ring step of the bore 7 or the pressure ring or the pressure plate are.
  • the flange 8 ' has in the transducer 5 in the vicinity of the housing 8 an annular groove or an annular zone with a relatively small wall thickness.
  • the area of the ring groove or the ring zone is resilient, similar to a diaphragm, and accordingly permits stronger vibrations of the housing 8 relative to the rest of the flange 8 '.
  • the converters 4 and 5 work as follows:
  • the electrodes 11 are connected to an AC voltage source via lines (not shown), so that the piezoceramic body 10 is subjected to a corresponding AC voltage. Due to the piezoelectric properties of the body 10, the body 10 begins to pulsate, ie structure-borne sound vibrations are generated in the body 10. These are transferred to the housing 8 via the thin connecting layer 12, and because of the relative mobility between the piezoceramic body 10 and the cylindrical part of the housing 8, relatively large amplitudes can occur as soon as a resonance frequency is reached. With regard to large amplitudes, it is particularly advantageous if the end face 8 'is relatively thin compared to the adjacent peripheral surfaces of the housing 8.
  • peripheral wall is divided by the area 8 ′′′ with a small wall thickness
  • the parts of the housing 8 or the flange 8 Flansch lying on the side of the area 8 ′′′ facing away from the end face 8 'relative should be heavy or massive.
  • the sound field generated in this way in channel 2 is influenced by the vortices in the channel of the gaseous medium flowing through channel 2. Accordingly, depending on the flow rate of the gaseous medium, a different proportion of the sound power reaches the closed end face 8 'of the housing 8 of the transducer 5 working as a receiver.
  • the sound coming to the transducer 5 sets the closed end face 8 'of the associated housing 8 in vibrations, which are practically completely transferred to the piezoceramic body 10 due to the design and arrangement of the transducer 5. Due to the mechanical vibrations, a corresponding electrical alternating voltage can be tapped off at the electrodes 11 of the piezoceramic body 10 of the transducer 5, which can be registered, for example, with an evaluation circuit.
  • the piezoelectric body 10 in a layered manner by arranging a plurality of approximately parallel metal layers between layers of piezoceramic material between the outer electrodes 11.
  • the metal layers are alternately electrically connected to one or the other electrode 11.
  • relatively low electrical voltages are sufficient to Piezoceramic material of the body 10 to generate high electrical fields and thus pronounced mechanical vibrations.
  • relatively high electrical powers can be generated.
  • the housing 8 is preferably made of metal, glass or ceramic material, the respective materials being selected or composed or alloyed as far as possible in such a way that the piezoelectric or electrostrictive body 10 and the housing 8 have approximately the same density and approximately the same expansion coefficient when the temperature changes.
  • both the housing 8 and the piezoelectric body 10 consist of ceramic materials.
  • thermal conductivity of ceramic materials is relatively good, so that temperature changes in the material propagate quickly and, at most, brief mechanical stresses occur in the ceramic material due to a temperature gradient.
  • the mechanical stresses caused by temperature changes therefore have only a minor influence on the vibration behavior of the transducer.
  • the good thermal conductivity and the low expansion coefficient also have the advantage that the connection or adhesive layer between the housing 8 and the piezoelectric or electrostrictive body 10 in the event of temperature changes only little shear stress is applied to the converter.
  • the vibrations generated by the piezoelectric or electrostrictive body 10 are transmitted particularly well to the housing 8 if ceramic material is used for the body 10 and housing 8, because the material properties are then particularly similar.
  • the housing 8 When the housing 8 is made of metal, it is fundamentally possible to conductively connect one of the electrodes 11 to the metal housing 8 and to connect the housing 8 as an electrical line between the one electrode and a driver or evaluation circuit.
  • the electrically conductive connection between the end face 8 'and the adjacent electrode 11 can be made, for example, by using an electrically conductive adhesive for the connecting layer 12, for example a silver-epoxy material.
  • the transducers according to the invention can also be used for other purposes in addition to flow meters.
  • the transducers are suitable for motion detectors which emit an ultrasound beam and evaluate the echo which may be thrown back, in order, for example, to use the Doppler effect to register movements of the objects or surfaces reflecting the sound waves.
  • the transducers according to the invention are also suitable for distance detectors in which a short sound pulse is emitted and the transit time is registered. Such detectors can also be used as level meters by determining the vertical distance of the top of the product from the detector.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Piezo-Electric Transducers For Audible Bands (AREA)
  • Transducers For Ultrasonic Waves (AREA)

Claims (16)

  1. Transducteur électro-acoustique (4, 5) destiné à être utilisé en émetteur acoustique et/ou récepteur acoustique de champs sonores dans des milieux gazeux, comprenant un corps à électro-striction ou piézo-électrique (10) qui est disposé dans une cage annulaire (8) entourant le corps au moins dans certaines zones et qui est équipé d'électrodes (11) qui servent à prélever une tension électrique alternative en cas d'apparition de vibrations acoustiques dans le corps (10) ou à envoyer dans le corps une tension électrique alternative générant des vibrations acoustiques dans le corps,
       caractérisé en ce que
       la cage (8) comporte une surface extrême fermée (8′) de rayonnement du son ou de réception du son et le corps (10) est fixé à cette surface extrême (8′), mais avec mobilité par rapport à la partie annulaire de la cage (8) qui entoure le corps (10), un volume annulaire constituant une zone d'espacement ou un intervalle rempli d'air subsistant entre le corps (10) et la partie de la cage qui entoure ce dernier.
  2. Transducteur selon la revendication 1,
       caractérisé en ce que
       le côté de la cage (8) qui est tourné à l'opposé de la surface extrême fermée de la cage (8) est recouvert ou scellé par une matière molle, par exemple de la silicone.
  3. Transducteur selon l'une des revendications 1 à 3,
       caractérisé en ce que
       le corps (10) est fixé à la surface extrême fermée de la cage (8) au moyen d'une matière de scellement en couche mince ou d'une couche de liaison (12), par exemple en résine époxy.
  4. Transducteur selon la revendication 3,
       caractérisé en ce que
       la matière de scellement ou la couche de liaison (12) est d'une part suffisamment dure pour une transmission de vibrations mécaniques ou d'ondes sonores entre le corps (10) et la surface extrême (8′) et d'autre part encore suffisamment molle pour que l'intensité des vibrations ou des ondes sonores présente un maximum principal marqué à une fréquence de résonnance et pour que les maxima secondaires apparaissant éventuellement dans d'autres plages de fréquence, en particulier voisines, soient comparativement faibles.
  5. Transducteur selon l'une des revendications 3 ou 4,
       caractérisé en ce que
       la matière de scellement ou la couche de liaison (12) contient plus de 50% en volume de poudre de quarts et/ou de poudre métallique.
  6. Transducteur selon l'une des revendications 1 à 5,
       caractérisé en ce que
       la cage (8) est montée sur un élément de support (corps métallique 1) à distance de sa surface extrême (8′) avec interposition d'une matière molle (couche intermédiaire 9) s'opposant à une transmission de vibrations mécaniques ou d'ondes sonores, telle que par exemple de la silicone.
  7. Transducteur selon la revendication 6,
       caractérisé en ce que
       une bride (8˝) ou analogue à l'aide de laquelle la cage (8) se monte sur l'élément de support (corps métallique 1) avec interposition d'une couche de matière molle (couche intermédiaire 9) est disposée à proximité de ou sur la surface extrême de la cage (8) qui est tournée à l'opposé de la surface extrême fermée.
  8. Transducteur selon la revendication 7,
       caractérisé en ce que
       la bride annulaire (8′) entourant la cage (8) est relativement lourde ou a une épaisseur notablement supérieure à celle du reste de la cloison de la cage (8).
  9. Transducteur selon l'une des revendications 7 ou 8,
       caractérisé en ce que
       la bride (8′) repose à l'aide d'une couche (9) de matière molle sur une surface de l'élément de support (corps métallique 1) qui est tournée à l'opposé du champ sonore (canal 2) et en ce que la cage (8) est disposée de manière à laisser subsister un volume annulaire d'espacement dans un trou (7) qui traverse l'élément de support (corps métallique 1) de la surface côté bride au côté tourné vers le champ sonore.
  10. Transducteur selon l'une des revendications 1 à 9,
       caractérisé en ce que
       la cloison de la circonférence de la cage (8) comporte une partie annulaire (8‴) dont l'épaisseur de la cloison est réduite entre sa surface extrême (8′) et une pièce ou une partie ou une bride (8˝) servant à fixer la cage (8), la partie annulaire (8‴) comportant par exemple une gorge annulaire ouverte vers le côté extérieur de la cage (8).
  11. Transducteur selon la revendication 10,
       caractérisé en ce que
       les parties de la cage et de la bride situées sur le côté de la partie annulaire (8‴) qui est tourné à l'opposé de la surface extrême (8′) sont plus lourdes et/ou plus massives que les autres parties de la cage (8).
  12. Transducteur selon l'une des revendications 1 à 11,
       caractérisé en ce que
       la surface extrême (8′) a une épaisseur de cloison inférieure à celle de la cloison voisine de la circonférence de la cage (8).
  13. Transducteur selon l'une des revendications 1 à 12,
       caractérisé en ce que
       l'extrémité du corps (10) qui est distante de la surface extrême (8′) est alourdie par ou reliée à une masse inerte ou à un élément de couverture ou une couche (14) qui ferme l'extrémité de la cage (8) qui est distante de la surface extrême (8′).
  14. Transducteur selon l'une des revendications 1 à 13,
       caractérisé en ce que
       la cage (8) est montée entre des joints toriques (15, 16) au moyen d'une bride (8˝) qui est axialement à distance de sa surface extrême (8′).
  15. Transducteur selon l'une des revendications 1 à 14,
       caractérisé en ce que
       une bride (8˝) côté cage, servant à fixer la cage (8) et axialement distante de sa surface extrême (8′) comporte au voisinage de la cage une zone annulaire ayant une épaisseur de cloison réduite en forme de membrane ou une gorge annulaire.
  16. Transducteur selon l'une des revendications 1 à 15,
       caractérisé en ce que
       la cage (8) est en métal, en verre et/ou - de préférence - en matière céramique, la matière de la cage étant de préférence sélectionnée ou composée de manière que la manière du corps (10) et la matière de la cage aient un coefficient de dilatation à peu près égal en cas de variations de température.
EP89107599A 1988-05-05 1989-04-27 Transducteur électro-acoustique Expired - Lifetime EP0340624B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE8805953U 1988-05-05
DE8805953U DE8805953U1 (de) 1988-05-05 1988-05-05 Elektroakustischer Wandler

Publications (3)

Publication Number Publication Date
EP0340624A2 EP0340624A2 (fr) 1989-11-08
EP0340624A3 EP0340624A3 (fr) 1991-10-16
EP0340624B1 true EP0340624B1 (fr) 1995-02-01

Family

ID=6823723

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89107599A Expired - Lifetime EP0340624B1 (fr) 1988-05-05 1989-04-27 Transducteur électro-acoustique

Country Status (2)

Country Link
EP (1) EP0340624B1 (fr)
DE (2) DE8805953U1 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4311963C2 (de) * 1993-04-10 1996-10-24 Endress Hauser Gmbh Co Füllstandsmeßgerät
DE4443415A1 (de) * 1994-12-06 1996-06-13 Siemens Ag Vorrichtung zur Aufnahme eines Schallwandlers und Ultraschall-Durchflußmesser mit derselben
DE29611678U1 (de) * 1996-07-04 1997-08-07 Siemens AG, 80333 München Schallwandler, insbesondere Ultraschallwandler
DE20309788U1 (de) * 2003-06-24 2004-11-04 Bürkert Werke GmbH & Co. KG Durchflussmesser nach dem Vortex-Prinzip
EP3098622B1 (fr) * 2015-05-29 2020-01-01 Consilium SAL Navigation AB Dispositif électronique intégré dans la coque pour un navire

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5318893B2 (fr) * 1971-12-03 1978-06-17
US3943388A (en) * 1974-06-27 1976-03-09 Fred M. Dellorfano, Jr. Electroacoustic transducer of the flexural vibrating diaphragm type
DE2839091C2 (de) * 1978-09-08 1980-03-13 Honeywell-Elac-Nautik Gmbh, 2300 Kiel Elektroakustischer Wandler
US4240002A (en) * 1979-04-02 1980-12-16 Motorola, Inc. Piezoelectric transducer arrangement with integral terminals and housing
JPS5832559B2 (ja) * 1979-07-04 1983-07-13 株式会社 モリタ製作所 空中超音波パルスの伝送方式並びにこれに用いる超音波送受波具
DE3005708C2 (de) * 1980-02-15 1984-08-30 Siemens AG, 1000 Berlin und 8000 München Wandlerplatte für piezoelektrische Wandler
DE3012038C2 (de) * 1980-03-28 1982-08-19 Honeywell-Elac-Nautik Gmbh, 2300 Kiel Elektroakustischer Wasserschallwandler
US4556814A (en) * 1984-02-21 1985-12-03 Ngk Spark Plug Co., Ltd. Piezoelectric ultrasonic transducer with porous plastic housing

Also Published As

Publication number Publication date
DE8805953U1 (de) 1988-07-07
DE58908955D1 (de) 1995-03-16
EP0340624A3 (fr) 1991-10-16
EP0340624A2 (fr) 1989-11-08

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