DK172871B1 - An ultrasonic transducer - Google Patents
An ultrasonic transducer Download PDFInfo
- Publication number
- DK172871B1 DK172871B1 DK96597A DK96597A DK172871B1 DK 172871 B1 DK172871 B1 DK 172871B1 DK 96597 A DK96597 A DK 96597A DK 96597 A DK96597 A DK 96597A DK 172871 B1 DK172871 B1 DK 172871B1
- Authority
- DK
- Denmark
- Prior art keywords
- cable
- disc
- ultrasonic transducer
- holder
- conductor
- Prior art date
Links
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
- 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
Description
i DK 172871 B1in DK 172871 B1
Opfindelsen omhandler en ultralydstransducer med et cylinder-formet hus med en plan bund, hvor huset indeholder en piezoelektrisk keramisk skive med anlæg mod husets bund, hvor husets bund danner en første elektrisk tilslutning til den pie-5 zoelektriske keramiske skive, og hvor en fjeder, der er omgivet af et fjederstyr, har anlæg mod den piezoelektriske keramiske skive, og modsat piezoskiven har fjederen kontakt med en elektrisk ledende skive, hvor fjederen danner en anden elektrisk forbindelse mellem piezoskiven og den elektrisk le-10 dende skive.The invention relates to an ultrasonic transducer having a cylindrical housing with a flat bottom, the housing containing a piezoelectric ceramic disc with abutment to the bottom of the housing, the housing bottom forming a first electrical connection to the piezo-electric ceramic disc and a spring, which is surrounded by a spring guide, has abutment against the piezoelectric ceramic disc, and opposite to the piezo disc, the spring contacts an electrically conductive disc, the spring forming another electrical connection between the piezo disc and the electrically conductive disc.
DE 43 30 745 Cl beskriver en ultralydstransducer med et cylinderformet hus med en plan bund, som den piezoelektriske keramiske skive har anlæg mod. Husets bund har en cirkelfor-15 met fordybning langs husets væg til optagelse af en lodning til elektrisk forbindelse til en af den piezoelektriske keramiske skives terminaler. Ved at fordybningen ligger langs væggen opnås, at den piezoelektriske keramiske skive kan placeres uden hensyn til loddepunktets placering. Imidlertid vil 20 lodningerne sætte en grænse for, hvor høj temperatur transduceren kan tåle.DE 43 30 745 CI discloses an ultrasonic transducer with a cylindrical housing with a flat bottom against which the piezoelectric ceramic disc has abutment. The bottom of the housing has a circular groove along the wall of the housing for receiving a solder for electrical connection to one of the terminals of the piezoelectric ceramic disc. By the recess lying along the wall, it is achieved that the piezoelectric ceramic disc can be placed regardless of the soldering point location. However, the 20 solder will limit how high the transducer can withstand.
Fra DK 93 00 409 U4 kendes en ultralydstransducer hvor en piezoelektrisk skive kun er adskilt fra medietrykket af en 25 tynd metalfilm, hvorved medietrykket overføres til piezoskiven. Herved kræves understøtning af skivens bagside, hvor understøtningen vil være mangelfuld på grund af, at der skal være frigang til de elektriske ledninger. Selv moderate medietryk kan forårsage brud på piezoskiven, og dermed ikke kun 30 en ophørt målefunktion, men samtidig risiko for medieudtræng-ning gennem transduceren.From DK 93 00 409 U4 an ultrasonic transducer is known in which a piezoelectric disc is separated from the media pressure only by a thin metal film, whereby the media pressure is transferred to the piezo disc. This requires support of the back of the disc, where the support will be defective due to the release of the electrical wires. Even moderate media pressure can cause breakage of the piezo disk, and thus not only a discontinuous measurement function, but at the same time the risk of media penetration through the transducer.
EP 0 260 335 omhandler ligeledes en ultralydstransducer, hvor en fjeder trykker et piezoelektrisk krystal mod en bund i et 35 transducer hus. Den elektriske tilledning til krystallet sker dels gennem transducer huset og dels gennem fjederen. Imidlertid kan der opbygges højspænding over det piezoelektriske DK 172871 B1 2 krystal, når krystaller ikke er tilsluttet. Tilslutning til den efterfølgende elektronik kan medføre ødelæggelse af halvledere, med mindre der tages særlige forholdsregler for tilslutning.EP 0 260 335 also discloses an ultrasonic transducer in which a spring presses a piezoelectric crystal against a bottom of a transducer housing. The electrical supply to the crystal takes place partly through the transducer housing and partly through the spring. However, high voltage can be built up over the piezoelectric DK 172871 B1 crystal when crystals are not connected. Connecting to the subsequent electronics can cause semiconductor damage unless special precautions are taken.
55
Der er opfindelsens formål at frembringe en enkel og billig ultralydstransducer, som kan modstå højt medietryk, og som fungerer fejlfrit over et stort temperaturinterval, hvor ultralydstransducere er udformet, så man undgår opbygning af 10 højspænding over det piezo elektriske krystal i ikke tilsluttet tilstand.It is an object of the invention to provide a simple and inexpensive ultrasonic transducer which can withstand high media pressure and which operates flawlessly over a large temperature range where ultrasonic transducers are designed to avoid building up of high voltage across the piezo electric crystal in unconnected state.
Den stillede opgave kan løses med en ultralydstransducer, som den der er beskrevet i indledningen, hvis den udformes såle-15 des, at den ledende skive i ikke tilsluttet tilstand af fjederen trykkes til anlæg mod en låsering med kontakt til huset og kortslutter den piezoelektriske keramiske skive, mens ved tilslutning af kabel trykkes den ledende skive fri fra låseringen, og der skabes elektrisk forbindelse mellem kabel og 20 den piezoelektriske keramiske skive.The posed task can be solved with an ultrasonic transducer, such as the one described in the preamble, if it is designed so that the conductive disk in the unconnected state of the spring is pressed into abutment against a locking ring with contact to the housing and shortens the piezoelectric ceramic disc, while connecting cable, the conductive disc is released from the locking ring and electrical connection is made between the cable and the piezoelectric ceramic disc.
Herved kan opnås, at den elektriske tilslutning til den piezoelektriske keramiske skive foregår uden lodning, og ultralydstransduceren er kortsluttet, når kablet fjernes, og der 25 kan ikke opbygges højspænding over den piezoelektriske keramiske skive. Således bliver kredsløb til beskyttelse mod højspænding unødvendige, og eventuelle skader på den elektronik, der tilsluttes, kan undgås. Ligeledes forsvinder den risiko, der er for elektrisk stød for den elektriker, som skal monte-30 re kabler på transduceren.Hereby it can be achieved that the electrical connection to the piezoelectric ceramic disc takes place without soldering, and the ultrasonic transducer is short-circuited when the cable is removed and no high voltage can be built up over the piezoelectric ceramic disc. Thus, high voltage protection circuits become unnecessary and any damage to the electronics connected can be avoided. Likewise, the risk of electric shock to the electrician having to install cables on the transducer disappears.
Kortslutningen mellem den ledende skive og låseringen kan ske med en ledende pakning, hvorved transduceren lukkes tæt mod omgivelserne. Herved opnås stor sikkerhed for, at fremmedle-35 gemer hindres adgang til transducerens indre, når kabelholderen er afmonteret. Således kan transducerhuset svejses fast DK 172871 B1 3 til en rørkonstruktion længe før resten af flowmåleren monteres .The short circuit between the conductive disk and the locking ring can be done with a conductive gasket, thereby closing the transducer tightly against the surroundings. This provides great assurance that foreign matter is obstructed from access to the interior of the transducer when the cable holder is removed. Thus, the transducer housing can be welded to a pipe structure long before the rest of the flow meter is mounted.
Tykkelsen af husets bund kan være tilpasset ultralydsbølge-5 længden i husets materiale. Herved kan opnås, at piezoskiven svinger på en resonansfrekvens for husets bund, så overførsel af svingninger fra piezoskiven gennem bunden foregår med små tab.The thickness of the base of the housing may be adapted to the ultrasonic wavelength of the housing material. Hereby it can be achieved that the piezo disk oscillates at a resonant frequency for the housing bottom, so that the transmission of oscillations from the piezo disk through the base takes place with small losses.
10 Kablet kan være monteret i en holder, som skrues i huset, hvor holderen har midler til kabelaflastning, og hvor holderen danner den første elektriske forbindelse fra kablets første leder til huset ved anlæg af en flange mod låseringen, mens kablets anden leder danner den anden elektriske forbin-15 delse gennem et centralt fremspring på holderen, hvor holderens fremspring og centerelektroden under iskruning af holderen trykker skiven væk fra låseringen ved samtidig sammentrykning af fjederen. Herved kan opnås en enkel og effektiv kabeltilslutning uden brug af lodning. Ved at undgå lodning i 20 ultralydstransduceren kan den anvendes ved høje temperaturer, hvor lodninger smelter.The cable may be mounted in a holder which is screwed into the housing, where the holder has means for cable relief and wherein the holder forms the first electrical connection from the first conductor of the cable to the housing by the application of a flange to the locking ring, while the second conductor of the cable forms the second electrical connection through a central protrusion on the holder, whereby the protrusion of the holder and the center electrode during ice screwing of the holder presses the disc away from the locking ring by simultaneously compressing the spring. This enables a simple and efficient cable connection without soldering. By avoiding soldering in the 20 ultrasonic transducer, it can be used at high temperatures where soldering melts.
Holderens fremspring kan være dannet af en isolatorskive med en central åbning til optagelse af kablets anden leder, og af 25 en tryksko, der er ledende, og som ligeledes har en central åbning til optagelse af kablets anden leder. Herved kan opnås en direkte forbindelse fra kablets anden leder til den ledende skive, og videre gennem fjederen til piezoskiven.The projection of the holder may be formed by an insulating disc having a central opening for receiving the second conductor of the cable, and by a pressure shoe which is conductive and which also has a central opening for receiving the second conductor of the cable. Hereby a direct connection can be obtained from the cable's second conductor to the conductive disk, and further through the spring to the piezo disk.
30 Holderens flange kan være udført med en hals med en åbning til optagelse af kablets anden leder og kablets isolation, mens kablets første leder forløber udvendigt på flangens hals, hvor flangens hals og den første leder kan være omgivet af et rør.The flange of the holder may be provided with a neck with an opening for receiving the second conductor of the cable and the insulation of the cable, while the first conductor of the cable extends externally on the neck of the flange, where the neck of the flange and the first conductor may be surrounded by a pipe.
3535
Med fordel kan kablet bestå af en første sektion, som er højtemperaturbestandig, hvor den første kabelsektion med en ka- DK 172871 B1 4 belsamling står i forbindelse med en anden kabelsektion, hvor kabelsamlingen indeholder et elektronisk kredsløb. Herved kan opnås, at det elektroniske kredsløb fjernes fra selve ultralydstransduceren, som herved kan anbringes ved meget høje om-5 giveIsestemperaturer.Advantageously, the cable may consist of a first section, which is high temperature resistant, where the first cable section with a cable assembly communicates with a second cable section, where the cable assembly contains an electronic circuit. This can be achieved by removing the electronic circuit from the ultrasonic transducer itself, which can hereby be placed at very high ambient temperatures.
Kabelsamlingens elektroniske kredsløb kan med fordel indeholde en spole til impedanstilpasning og til tilpasning af et resonanssystem. Herved kan den piezoelektriske keramiske ski-10 ve sammen med spolen danne en svingningskreds, hvis resonansfrekvens er sammenfaldende med det signal, svingningskredsen forsynes med.The electronic circuit of the cable assembly may advantageously include a coil for impedance matching and for adapting a resonant system. Hereby, the piezoelectric ceramic disk may together with the coil form a vibration circuit, the resonant frequency of which coincides with the signal provided by the vibration circuit.
Det elektroniske kredsløb kan have midler til både forstærk-15 ning og impedansomsætning, både i retning mod transduceren og mod tilslutningskablet. Herved bliver længden af kabler mellem den tilhørende elektroniske enhed og transduceren ukritisk.The electronic circuit may have means for both gain and impedance conversion, both in the direction of the transducer and towards the connection cable. This makes the length of cables between the associated electronic device and the transducer uncritical.
20 Teaninasbeskrivelse: I det følgende beskrives ultralydstransduceren ud fra tegninger, der med 25 figur 1 viser et snit gennem et transducerhus, og figur 2 viser et snit gennem en transducer med monteret ka bel, og hvor 30 figur 3 viser transducerens kabeltilslutning og en kabelsamling.20 Theaninase Description: The following describes the ultrasonic transducer from drawings which, with FIG.
På figur 1 er vist et transducerhus 2 med en bund 3, som dan-35 ner et vindue for ultralyd, der genereres af en piezoelek- trisk keramisk skive 4, som fastholdes til anlæg mod bunden 3 af en trykfjeder 5. Fjederen 5 er ført inden i en fjederhol- DK 172871 B1 5 der 6, og fjederen 5 er modsat den piezoelektriske keramiske skive 4 i anlæg mod en ledende skive 7, som af fjederen trykkes til anlæg mod en låsering 8.Fig. 1 shows a transducer housing 2 with a bottom 3 which forms an ultrasonic window generated by a piezoelectric ceramic disc 4 which is held to abut the bottom 3 by a pressure spring 5. The spring 5 is guided within a spring cavity 6 and the spring 5 is opposed to the piezoelectric ceramic disc 4 abutting a conductive disc 7 which is pressed by the spring to abut against a locking ring 8.
5 Den første elektriske forbindelse til den piezoelektriske keramiske skive 4 dannes ved hjælp af huset 2 og bunden 3. Den anden elektriske forbindelse til piezoskiven 4 dannes ved hjælp af fjederen 5, som er fort i den isolerende fjederholder 6.5 The first electrical connection to the piezoelectric ceramic disc 4 is formed by the housing 2 and the bottom 3. The second electrical connection to the piezo disc 4 is formed by the spring 5 which is fast in the insulating spring holder 6.
1010
Som vist på figur 1 er der anlæg mellem den ledende skive 7 og låseringen 8, hvorved piezoskiven 4 kortsluttes. Herved hindres opbygning af højspænding over den piezoelektriske keramiske skive, hvilket vil opstå ved temperaturændringer. Ved 15 kortslutning under transport og lagring sikres, at den elektriker, der på et senere tidspunkt montere kablet, ikke får en ubehagelig og farlig overraskelse i kraft af et elektrisk stød.As shown in Figure 1, there is abutment between the conductive disc 7 and the locking ring 8, whereby the piezo disc 4 is short-circuited. This prevents the build-up of high voltage over the piezoelectric ceramic disc, which will occur with temperature changes. With 15 short circuits during transport and storage, it is ensured that the electrician who later installs the cable does not get an unpleasant and dangerous surprise due to an electric shock.
20 Figur 2 viser ultralydstransduceren med monteret holder 13.20 Figure 2 shows the ultrasonic transducer with mounted holder 13.
Kablet 9 består af en første leder 10, en isolering 11 og en anden leder 12. Under iskruning af holderen 13 trykker en fjederskive 18 den første leder 10 til anlæg mod en ledende flange 14. Ligeledes kan den første leder være fastgjort ved 25 hjælp af et rør 15, som efter montage klemmes omkring kablet 9. Den anden leder 12 passerer isoleret gennem flangen 14 og videre gennem en isolator 16 til kontakt med en tryksko 17, hvor den anden leder 12 her er vist ombukket. Kablet er yderligere fastholdt ved hjælp af en tylle 19, som ved hjælp af 30 en omløber 20 sammenklemmes omkring kablet 9.The cable 9 consists of a first conductor 10, an insulation 11 and a second conductor 12. During the screwing of the holder 13, a spring washer 18 presses the first conductor 10 into abutment against a conductive flange 14. Similarly, the first conductor can be secured by means of 25 a tube 15 which, after mounting, is clamped around the cable 9. The second conductor 12 passes in isolation through the flange 14 and further through an insulator 16 for contact with a pressure shoe 17, the second conductor 12 being shown folded here. The cable is further secured by means of a sheave 19, which by means of a sheath 20 is clamped around the cable 9.
Under iskruning af holderen 13 vil trykskoen 17 og den ombukkede ende af den anden leder 12 danne anlæg mod den ledende skive 7. Herved vil der under fortsat iskruning af holderen 35 13 ske en sammentrykning af fjederen 5. Herved fjernes kort slutningen mellem den ledende skive 7 og låseringen 8 og ultralydstransduceren bliver funktionsdygtig.During ice screwing of the holder 13, the pressure shoe 17 and the folded end of the second conductor 12 form abutment against the conductive disk 7. This will result in a further compression of the spring 5. This will remove the short end between the conductive disk while continuing to ice the holder 35 13. 7 and the locking ring 8 and the ultrasonic transducer become operable.
DK 172871 B1 6 På figur 3 er kabelholderen 13 vist i adskilt tilstand - kablet 9 er fastgjort til flangen 14, hvor fjederskiven 18 er vist i en ikke tilspændt situation, idet fjederskiven 18 5 først spændes og klemmer kablets første leder mod flangen 14 under iskruning af holderen 13. En efterfølgende tilspænding af omløberen 20 vil medføre, at kabeltyllen 19 også spænder kablet 9. Kablet 9 fører til en kabelsamling 21, hvor kabelsamlingen kan indeholde et elektronisk kredsløb 22. Fra det 10 elektroniske kredsløb 22 og kabelsamlingen 21 fører yderligere et kabel 23 videre mod det elektroniske beregningskredsløb, som ultralydstransduceren samvirker med.In Fig. 3, the cable holder 13 is shown in a separate state - the cable 9 is attached to the flange 14, where the spring washer 18 is shown in an un-tensioned situation, the spring washer 18 5 first being tensioned and clamping the first conductor of the cable against the flange 14 during ice screwing. of the retainer 13. A subsequent tightening of the bypass 20 will cause the cable tuck 19 to also tension the cable 9. The cable 9 leads to a cable assembly 21, where the cable assembly can contain an electronic circuit 22. From the 10 electronic circuit 22 and the cable assembly 21 further cable 23 further towards the electronic calculation circuit with which the ultrasonic transducer cooperates.
Det elektroniske kredsløb 22 kan bestå af en spole til impe-15 danstilpasning og til opnåelse af en svingningskreds mellem spolen og den piezoelektriske keramiske skive 4. Ligeledes kan det elektroniske kredsløb 22 indeholde kredsløb til forstærkning og impedansomsætning, både mod kablet 9 og mod kablet 23. Kablet 23 kan levere den nødvendige strømforsyning 20 til elektronikenheden 22 samtidig med, at der overføres signaler. Ved at foretage den endelige signalbehandling tæt på ultralydstransduceren kan man vælge den mest hensigtsmæssige transmissionsform over kablet 23, som derved kan opnå en meget stor længde, hvis dette er nødvendigt.The electronic circuit 22 may comprise a coil for impedance matching and for obtaining a oscillation circuit between the coil and the piezoelectric ceramic disc 4. Likewise, the electronic circuit 22 may include circuits for amplification and impedance conversion, both against cable 9 and against cable 23. The cable 23 can supply the necessary power supply 20 to the electronics unit 22 while transmitting signals. By conducting the final signal processing close to the ultrasonic transducer, one can select the most convenient transmission mode over the cable 23, which can thereby achieve a very large length, if necessary.
2525
Ultralydstransduceren er speciel egnet til høje tryk i form af, at bunden 3 sammen med huset 2 kan modstå meget høje omgivelsestryk, og ultralydstransduceren kan ved sin opbygning være særlig egnet til ekstremt høje temperaturer, idet kabel-30 tilslutning foregår uden brug af lodning på noget tidspunkt.The ultrasonic transducer is particularly suitable for high pressures in that the bottom 3 together with the housing 2 can withstand very high ambient pressures, and the ultrasonic transducer may be particularly suitable for extremely high temperatures, with cable connection taking place without soldering on anything. point in time.
Den øvre temperaturgrænse vil være bestemt af det kabel, som anvendes. Således kan ultralydstransduceren arbejde ved temperaturer på 400-500°, hvis kablet 9 er et specielt højtemperaturkabel, hvorimod kablet 23 kan være af en almindelig ty-35 pe, idet dette kabel formodes kun at skulle anvendes på strækninger, hvor omgivelsestemperaturen er forholdsvis lavere.The upper temperature limit will be determined by the cable used. Thus, the ultrasonic transducer can operate at temperatures of 400-500 ° if the cable 9 is a special high temperature cable, whereas the cable 23 can be of a common type, this cable being presumed to be used only on stretches where the ambient temperature is relatively lower.
Claims (9)
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DK96597A DK172871B1 (en) | 1997-08-22 | 1997-08-22 | An ultrasonic transducer |
| RU2000107143A RU2185253C2 (en) | 1997-08-22 | 1998-08-19 | Ultrasonic transducer |
| CNB988100797A CN1154545C (en) | 1997-08-22 | 1998-08-19 | Ultrasonic transducer |
| PL33873398A PL187955B1 (en) | 1997-08-22 | 1998-08-19 | Ultrasound transducer |
| DE1998182623 DE19882623B4 (en) | 1997-08-22 | 1998-08-19 | Ultrasonic Transducers |
| PCT/DK1998/000358 WO1999010110A1 (en) | 1997-08-22 | 1998-08-19 | Ultrasonic transducer |
| AU87980/98A AU8798098A (en) | 1997-08-22 | 1998-08-19 | Ultrasonic transducer |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DK96597 | 1997-08-22 | ||
| DK96597A DK172871B1 (en) | 1997-08-22 | 1997-08-22 | An ultrasonic transducer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| DK96597A DK96597A (en) | 1999-02-23 |
| DK172871B1 true DK172871B1 (en) | 1999-08-23 |
Family
ID=8099497
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DK96597A DK172871B1 (en) | 1997-08-22 | 1997-08-22 | An ultrasonic transducer |
Country Status (7)
| Country | Link |
|---|---|
| CN (1) | CN1154545C (en) |
| AU (1) | AU8798098A (en) |
| DE (1) | DE19882623B4 (en) |
| DK (1) | DK172871B1 (en) |
| PL (1) | PL187955B1 (en) |
| RU (1) | RU2185253C2 (en) |
| WO (1) | WO1999010110A1 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10017068C1 (en) * | 2000-04-06 | 2001-11-15 | Siemens Ag | Transducer |
| US6973833B2 (en) * | 2002-03-12 | 2005-12-13 | Caldon, Inc. | Wafer and method |
| JP4900066B2 (en) * | 2007-06-12 | 2012-03-21 | ミツミ電機株式会社 | Manufacturing method of ultrasonic sensor |
| DE102011090082A1 (en) * | 2011-12-29 | 2013-07-04 | Endress + Hauser Flowtec Ag | Ultrasonic transducer for a flowmeter |
| DE102012108254A1 (en) * | 2012-09-05 | 2014-03-06 | systec Controls Meß- und Regeltechnik GmbH | Ultrasonic transducer and method of making an ultrasonic transducer |
| CN104359516A (en) * | 2014-11-07 | 2015-02-18 | 宁波美卓伦仪表有限公司 | Fully titanium alloy packaging ultrasonic-wave dual-use gas-liquid flow sensor |
| WO2018136044A1 (en) * | 2017-01-18 | 2018-07-26 | Siemens Aktiengesellschaft | Ultrasonic transducer and method of assembling the same |
| DE102019218033A1 (en) * | 2019-11-22 | 2021-05-27 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Ultrasonic unit for coupling ultrasonic waves into and / or from a medium |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB690489A (en) * | 1950-02-06 | 1953-04-22 | John William Fox | Improvements in or relating to ultra-sonic equipment |
| GB1230156A (en) * | 1968-10-22 | 1971-04-28 | ||
| US4148536A (en) * | 1976-11-22 | 1979-04-10 | Petropoulsos Nikolaostzakos J | Safety electrical receptacle |
| GB2059715B (en) * | 1979-09-18 | 1984-02-01 | Standard Telephones Cables Ltd | Electro acoustic transducers |
| DE3425176A1 (en) * | 1984-07-09 | 1986-02-20 | Fernsprech Und Signalbau Kg Sc | Piezoelectric telephone capsule |
| US5222899A (en) * | 1992-05-08 | 1993-06-29 | Hughes Aircraft Company | Electrostatic discharge safety connector for electro-explosive devices |
| DE4330745C1 (en) * | 1993-09-10 | 1995-04-27 | Siemens Ag | Ultrasonic transducer with adapter body |
-
1997
- 1997-08-22 DK DK96597A patent/DK172871B1/en not_active IP Right Cessation
-
1998
- 1998-08-19 PL PL33873398A patent/PL187955B1/en not_active IP Right Cessation
- 1998-08-19 CN CNB988100797A patent/CN1154545C/en not_active Expired - Lifetime
- 1998-08-19 WO PCT/DK1998/000358 patent/WO1999010110A1/en active Application Filing
- 1998-08-19 AU AU87980/98A patent/AU8798098A/en not_active Abandoned
- 1998-08-19 RU RU2000107143A patent/RU2185253C2/en not_active IP Right Cessation
- 1998-08-19 DE DE1998182623 patent/DE19882623B4/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| PL338733A1 (en) | 2000-11-20 |
| DE19882623B4 (en) | 2004-10-21 |
| DK96597A (en) | 1999-02-23 |
| AU8798098A (en) | 1999-03-16 |
| CN1275100A (en) | 2000-11-29 |
| CN1154545C (en) | 2004-06-23 |
| DE19882623T1 (en) | 2000-08-10 |
| WO1999010110A1 (en) | 1999-03-04 |
| PL187955B1 (en) | 2004-11-30 |
| RU2185253C2 (en) | 2002-07-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| B1 | Patent granted (law 1993) | ||
| B1 | Patent granted (law 1993) | ||
| PBP | Patent lapsed |
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