EP0583805A1 - Flex eines gespannter Wandler - Google Patents

Flex eines gespannter Wandler Download PDF

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Publication number
EP0583805A1
EP0583805A1 EP19930117557 EP93117557A EP0583805A1 EP 0583805 A1 EP0583805 A1 EP 0583805A1 EP 19930117557 EP19930117557 EP 19930117557 EP 93117557 A EP93117557 A EP 93117557A EP 0583805 A1 EP0583805 A1 EP 0583805A1
Authority
EP
European Patent Office
Prior art keywords
shell
transducer
stacks
cavity
reservoir
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Withdrawn
Application number
EP19930117557
Other languages
English (en)
French (fr)
Inventor
Bernard Tocquet
Michel Letiche
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.)
Thales SA
Original Assignee
Thomson CSF SA
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 Thomson CSF SA filed Critical Thomson CSF SA
Publication of EP0583805A1 publication Critical patent/EP0583805A1/de
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • G10K9/00—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers
    • G10K9/12—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated
    • G10K9/121—Flextensional transducers
    • 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
    • B06B1/0607—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 multiple elements
    • B06B1/0611—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 multiple elements in a pile
    • B06B1/0618—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 multiple elements in a pile of piezo- and non-piezoelectric elements, e.g. 'Tonpilz'

Definitions

  • the present invention relates to a flexural transducer. It applies to the emission or reception of acoustic waves in liquids.
  • Known flextensor transducers are generally composed of a flexible, watertight shell with a cylindrical side wall of elliptical cross section, vibrated by one or more pillars or bars of piezoelectric ceramic cells. Each pillar is kept in compression between the opposite parts furthest from the side wall. In emission, an alternating electric field is applied in the longitudinal direction of each pillar and the resulting movement, which takes place along the longitudinal axis of each pillar, is transmitted, amplified, to the surrounding liquid medium, the amplitude of this movement being maximum in the plane generated by the minor axes of the ellipses formed by each cross section.
  • the compression of the piezoelectric cells of each pillar is necessary to avoid breakage of the ceramic when the pillars are stressed in extension.
  • a first prestressing is applied to stacks of piezoelectric cells during the assembly of the stacks inside the shell.
  • the stacks extend, symmetrically on either side of mechanical wedging means centered inside the hull, along the major axis of the elliptical cross section of the hull.
  • This prestressing ensures the maintenance of the stacks in support respectively by a first end on the wedging means and by a second end on the inner part of the shell corresponding to one end of the major axis of the ellipse.
  • the preload is adjusted as a function of the operational depth of immersion of the transducer to compensate for the hydrostatic forces exerted on the outside of the hull and guarantee the constant maintenance of the stacks for the proper functioning of the transducer.
  • the mechanical wedging means comprise a frustoconical part making it possible, from its vertical displacement, to transmit the necessary pressure force on the stacks.
  • the movement of the frustoconical part is ensured by tightening or loosening a screw fixed on its upper part.
  • the tightening determines the amplitude of the prestressing force to be applied to the stacks.
  • the screw can be replaced by a hydraulic ram and the pressure exerted on the ram is determined from a pressure sensor.
  • the sensor measures the amplitude of the hydrostatic pressure applied to the shell of the transducer and makes it possible to adjust the pressure exerted on the ram.
  • this embodiment has the drawback that the prestressing exerted on the stacks during immersion is dependent on the hydrostatic forces exerted on the shell and that the use of such a transducer is limited by the mechanical resistance in compression of the piezoelectric cells. This drawback is also observed in the transducer according to patent FR-A-2 361 033. This embodiment also has the drawback that it requires a measurement means such as a sensor for measuring the hydrostatic pressure and a control means using this measurement to control a hydraulic ram.
  • the object of the invention is to overcome the aforementioned drawbacks.
  • the subject of the invention is a flextensor transducer composed of a flexible and waterproof shell with a cylindrical side wall of elliptical cross section comprising at least two stacks of piezoelectric cells aligned on the same longitudinal axis and held in abutment by one of their first end on two opposite parts of the shell by a fluidic device, characterized in that the stacks of piezoelectric cells are maintained respectively around a rod and provided respectively at their ends with two mechanical parts to establish a prestressing force independent of the hydrostatic pressure exerted on the shell of the transducer during its immersion, in that the fluidic device comprises a cavity into which the second ends of the stacks are introduced, filled with a fluid under pressure coming from an external reservoir placed at the same immersion depth as the transducer, to ensure that the first end of each of the stacks remains supported on the shell under the effect of the pressure of the fluid exerted on their second ends and compensate in the cavity for the effect of the hydrostatic pressure exerted on the hull.
  • the main advantage of the invention is that it makes it possible, on the one hand, to make the prestressing exerted on the stacks independent of the hydrostatic pressure exerted on the hull, and in this way, the transducers thus produced can operate at much higher immersions. to the usual immersions, and on the other hand, to use only a means of direct servo-control of the hydrostatic pressure applied to the shell of the transducer to the pressure applied to the stacks of piezoelectric cells.
  • a first embodiment of a flexuring transducer according to the invention is described below with the aid of FIG. 1.
  • This transducer comprises a flexible and watertight shell, with a cylindrical lateral wall of elliptical cross section 1, containing at least two pillars 2 and 3 formed respectively by a stack, around a rod 4 and 5, of a plurality of piezoelectric cells, 6i and 7i, ceramic.
  • the pillars 2 and 3 are provided at their ends with two mechanical parts 8 and 9 respectively 10, 11 to establish the prestressing force of the pillars 2 and 3 independent of the hydrostatic pressure exerted on the shell 1 during its immersion .
  • a fluidic device 12 is disposed between the ends of the two pillars 2 and 3 furthest from the shell 1.
  • This device consists of a cavity 13 filled with oil connected to an external reservoir 14 by a capillary pipe 15.
  • the cavity 13 is produced, for example, by means of a part of revolution forming a housing surrounding the two ends of the pillars 2 and 3.
  • At least two elastomeric seals 16, 17 seal the cavity 13 with the ends of the pillars 2 and 3.
  • the stiffness of the oil film is high at the operating frequency, and provides a high mass in the center of the cavity 13 in a manner identical to the known art.
  • the vibration speed being low since we are at the nodal point, the seals 16, 17 work in good conditions.
  • each pillar 2, 3 can optionally be supported on the shell 1 by means of an appropriate housing in the shell 1.
  • the mounting of a transducer can also be carried out according to a "collective" method, as shown in FIG. 2, by making the fluid housing 12 common to all the pillars 2 i . Under these conditions the housing-pillar assembly which has the shape of a "fishbone” is introduced into the shell 1 in a single operation and their common housing 12 and connected to a single oil tank 14 by the capillary pipe 15.
EP19930117557 1988-11-04 1989-11-03 Flex eines gespannter Wandler Withdrawn EP0583805A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8814416 1988-11-04
FR8814416A FR2639786B1 (fr) 1988-11-04 1988-11-04 Transducteur flextenseur

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
EP89403032.9 Division 1989-11-03

Publications (1)

Publication Number Publication Date
EP0583805A1 true EP0583805A1 (de) 1994-02-23

Family

ID=9371579

Family Applications (2)

Application Number Title Priority Date Filing Date
EP19930117557 Withdrawn EP0583805A1 (de) 1988-11-04 1989-11-03 Flex eines gespannter Wandler
EP89403032A Ceased EP0367681A1 (de) 1988-11-04 1989-11-03 Flexionsgespannter Wandler

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP89403032A Ceased EP0367681A1 (de) 1988-11-04 1989-11-03 Flexionsgespannter Wandler

Country Status (3)

Country Link
US (1) US4970706A (de)
EP (2) EP0583805A1 (de)
FR (1) FR2639786B1 (de)

Families Citing this family (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2688972B1 (fr) * 1988-04-28 1996-10-11 France Etat Armement Transducteurs electro-acoustiques comportant une coque emettrice flexible et etanche.
US5497357A (en) * 1988-12-23 1996-03-05 Alliedsignal Inc. Shock-resistant flextensional transducer
GB9010372D0 (en) * 1990-05-09 1990-06-27 Secr Defence Flextensional transducer
US5042611A (en) * 1990-05-18 1991-08-27 Texaco Inc. Method and apparatus for cross-well seismic surveying
FR2663182B1 (fr) * 1990-06-12 1992-09-18 Grosso Gilles Transducteur electro-acoustique immerge.
FR2663805B1 (fr) * 1990-06-26 1992-09-11 Thomson Csf Procede de fabrication d'un element magnetostrictif pour la realisation de transducteurs electro-acoustique et transducteuur electro-acoustique realise a l'aide de tels elements.
FR2672179B1 (fr) * 1991-01-25 1993-04-16 Thomson Csf Transducteur acoustique flextenseur pour immersion profonde.
US5155709A (en) * 1991-07-10 1992-10-13 Raytheon Company Electro-acoustic transducers
AU692960B2 (en) * 1994-12-23 1998-06-18 Marschall Acoustics Pty Ltd Hydrophone
US5926439A (en) * 1998-12-21 1999-07-20 The United States Of America As Represented By The Secretary Of The Navy Flextensional dual-section push-pull underwater projector
US5949741A (en) * 1998-12-21 1999-09-07 The United States Of America As Represented By The Secretary Of The Navy Dual-section push-pull underwater projector
US6076630A (en) * 1999-02-04 2000-06-20 Western Atlas International, Inc. Acoustic energy system for marine operations
FR2809580B1 (fr) 2000-05-26 2002-08-30 Thomson Marconi Sonar Sas Transducteur electrodynamique pour acoustique sous-marine
WO2007145731A2 (en) 2006-06-07 2007-12-21 Exxonmobil Upstream Research Company Compressible objects combined with a drilling fluid to form a variable density drilling mud
WO2007145734A2 (en) 2006-06-07 2007-12-21 Exxonmobil Upstream Research Company Compressible objects having partial foam interiors combined with a drilling fluid to form a variable density drilling mud
US8088716B2 (en) 2004-06-17 2012-01-03 Exxonmobil Upstream Research Company Compressible objects having a predetermined internal pressure combined with a drilling fluid to form a variable density drilling mud
CN100570708C (zh) * 2006-03-17 2009-12-16 中国科学院声学研究所 一种超低频水声换能器
EP2035651A4 (de) 2006-06-07 2009-08-05 Exxonmobil Upstream Res Co Verfahren zur herstellung von komprimierbaren objekten für eine bohrspülung variabler dichte
FR3026569B1 (fr) * 2014-09-26 2017-12-08 Thales Sa Antenne omnidirectionnelle

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR817640A (fr) * 1936-05-14 1937-09-07 J Carpentier Atel Microphone sous-marin spécial pour mouillage à grande profondeur, isolé ou en groupements directifs
US3731266A (en) * 1971-03-25 1973-05-01 Bell Lab Inc Inertia-compensated a.c. biased hydrophone incorporating a porous capacitance transducer
EP0215657A2 (de) * 1985-09-12 1987-03-25 British Aerospace Public Limited Company Sonarwandler

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3274538A (en) * 1960-09-19 1966-09-20 Benjamin L Snavely Electroacoustic transducer
US3328751A (en) * 1966-03-28 1967-06-27 Dynamics Corp Massa Div Electroacoustic transducer
FR2361033A1 (fr) * 1976-08-03 1978-03-03 France Etat Transducteurs piezoelectriques et antennes acoustiques immergeables a grande profondeur
US4409681A (en) * 1979-03-15 1983-10-11 Sanders Associates, Inc. Transducer
US4420826A (en) * 1981-07-06 1983-12-13 Sanders Associates, Inc. Stress relief for flextensional transducer
US4764907A (en) * 1986-04-30 1988-08-16 Allied Corporation Underwater transducer
US4845687A (en) * 1988-05-05 1989-07-04 Edo Corporation, Western Division Flextensional sonar transducer assembly

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR817640A (fr) * 1936-05-14 1937-09-07 J Carpentier Atel Microphone sous-marin spécial pour mouillage à grande profondeur, isolé ou en groupements directifs
US3731266A (en) * 1971-03-25 1973-05-01 Bell Lab Inc Inertia-compensated a.c. biased hydrophone incorporating a porous capacitance transducer
EP0215657A2 (de) * 1985-09-12 1987-03-25 British Aerospace Public Limited Company Sonarwandler

Also Published As

Publication number Publication date
FR2639786A1 (fr) 1990-06-01
FR2639786B1 (fr) 1991-07-26
US4970706A (en) 1990-11-13
EP0367681A1 (de) 1990-05-09

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