EP0014874B1 - Détecteur d'incendie à rayonnement pulsé - Google Patents

Détecteur d'incendie à rayonnement pulsé Download PDF

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Publication number
EP0014874B1
EP0014874B1 EP80100508A EP80100508A EP0014874B1 EP 0014874 B1 EP0014874 B1 EP 0014874B1 EP 80100508 A EP80100508 A EP 80100508A EP 80100508 A EP80100508 A EP 80100508A EP 0014874 B1 EP0014874 B1 EP 0014874B1
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EP
European Patent Office
Prior art keywords
radiation
receiver
signal
fire alarm
alarm according
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
Application number
EP80100508A
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German (de)
English (en)
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EP0014874A3 (en
EP0014874A2 (fr
Inventor
Walter Schnell
Jürg Muggli
Gustav Pfister
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Cerberus AG
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Cerberus AG
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Publication date
Priority claimed from CH186779A external-priority patent/CH641584A5/de
Application filed by Cerberus AG filed Critical Cerberus AG
Publication of EP0014874A2 publication Critical patent/EP0014874A2/fr
Publication of EP0014874A3 publication Critical patent/EP0014874A3/de
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Publication of EP0014874B1 publication Critical patent/EP0014874B1/fr
Expired legal-status Critical Current

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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
    • G08B17/103—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device
    • G08B17/107—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device for detecting light-scattering due to smoke
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
    • G08B17/11—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using an ionisation chamber for detecting smoke or gas
    • G08B17/113—Constructional details

Definitions

  • the invention relates to a fire detector with a pulsed radiation source, the electromagnetic radiation of which is directed into a measuring chamber to which the air to be monitored for the occurrence of smoke and aerosol particles has access, and with a sensor to which an evaluation unit is connected , which triggers an alarm signal as soon as the value of the signal emitted by the transducer exceeds a predetermined threshold.
  • Such fire detectors which are also known as optical smoke detectors, evaluate the fact that the radiation emitted into a measuring room by a radiation source, e.g. B. UV, visible light or infrared radiation, in the presence of smoke particles or fire aerosol in the measuring chamber is influenced in a certain way.
  • a radiation source e.g. B. UV, visible light or infrared radiation
  • These fire detectors preferably operate according to the scattered radiation principle, with a scattered radiation receiver which is not struck by direct radiation and which receives the radiation scattered by smoke particles and triggers a fire alarm signal as soon as the scattered radiation intensity exceeds a predetermined threshold, e.g. in US Patent 4175865 or CH Patent 592 932.
  • a disadvantage of such fire detectors is that they only react to heavily scattering smoke, so-called white smoke, such as that which arises, for example, in the case of a damp material fire.
  • white smoke such as that which arises, for example, in the case of a damp material fire.
  • black smoke which often occurs in rapidly developing fires or incomplete combustion.
  • Previously known scattered-radiation fire detectors were therefore unable to report fire types which are associated with the occurrence of strongly radiation-absorbing, i.e. black, smoke. This is particularly disadvantageous in the case of rapidly developing fires in which scattered radiation detectors often only trigger an alarm signal too late.
  • Extinction fire detectors are able to detect different types of smoke with a relatively uniform sensitivity.
  • they have the disadvantage that a relatively small change in a relatively large irradiation value must be reliably detected, which in practice requires extremely good and correspondingly complicated and expensive long-term stabilization of the radiation source. Therefore, scattered light detectors have largely prevailed in practice, in which the deviation of a size of zero, which can be determined much more easily and without great stabilization effort, is determined, although the disadvantage must be accepted that such scattered light detectors do not react to all types of fire.
  • optical fire detectors Another disadvantage inherent in all known optical fire detectors is that they only respond to smoke particles whose dimensions are greater than approximately the radiation wavelength, ie greater than approximately 1 J lm. Smaller particles, which preferably occur in the early stages of a fire, cannot be detected, so that such optical fire detectors often only trigger an alarm signal at a late point in time, so that usually other, more responsive types of fire detectors, such as e.g. B. ionization fire alarm, the preference is given, but then the disadvantage must be accepted that radioactive preparations must be used, which in turn have other undesirable effects.
  • the invention has for its object to avoid the above-mentioned disadvantages of known optical fire detectors and to create a fire detector that reacts to fire products that absorb radiation pulses, safely and with faster response and higher sensitivity and which is also simple and small in size, and works reliably and is not susceptible to faults over longer periods of time.
  • this object is achieved in that, in the case of a fire detector of the type mentioned at the outset, the sensor is an acoustic sensor which picks up the air vibrations generated by the absorption of the radiation pulses by the particles.
  • the fire detector according to the invention, it can be designed such that it responds to the various types of fire occurring in practice in the manner mentioned, ie also reacts in the same way to white smoke and to invisible aerosol particles.
  • This is achieved by additionally providing a scattered radiation receiver which scatters the smoke particles in the measuring chamber in the radiation region of the radiation source Can absorb radiation, but receives no direct radiation from the radiation source.
  • air pressure pulses are generated by the absorption of the radiation pulses generated by the radiation source from particles in the radiation area.
  • the air pressure fluctuations generated during each radiation pulse are collected and summed by an acoustic transducer, at the output of which an output pulse occurs in coincidence with the radiation pulses, which is further evaluated by an evaluation unit for alarm signaling.
  • connections between the measuring chamber and the evaluation unit can be designed as electrical lines, with the acoustic transducer being an acoustic-electrical converter, e.g. a microphone.
  • connections between the measuring chamber and the evaluation unit consist exclusively of radiation-conducting elements, so-called light guides.
  • the radiation source is expediently not arranged in the measuring chamber but in the evaluation unit.
  • the radiation pulses emitted by the radiation source are transmitted to the measuring chamber by an optical fiber.
  • an acoustic-optical converter which also receives radiation from the radiation source via an optical fiber and, when air vibrations occur, redirects it to the evaluation unit in a different form via another optical fiber.
  • the changed optical signal is received by a radiation detector and converted into an electrical signal, which is further evaluated by the signal circuit for alarm signaling.
  • This development of the invention has the advantage that there are no electrical connections between the measuring chamber and the evaluation unit, and the signal transmission takes place exclusively by optical means.
  • a fire detector is therefore completely independent of electrical disturbances, for example short-term network fluctuations or voltages induced in the lines.
  • it is automatically explosion-proof, i. H. it can also be used in potentially explosive environments without restriction.
  • a radiation source 5 for example a LASER or a diode emitting light or infrared radiation, is located in the measuring chamber on the upper cover 3.
  • This radiation source is operated in pulses by an oscillator 6 and emits radiation pulses with a specific pulse frequency, for example in the range between 1 and 20 kHz, into the interior of the measuring chamber.
  • an acoustic pickup 7 is provided, e.g. B. a capacitive electret microphone with an electrically polarized film. If there is smoke or fire aerosol in the measuring chamber 1, the radiation pulses are absorbed by the particles in the radiation area. These particles heat up briefly and an air pressure wave arises from each particle. The individual pressure pulses add up and can thus be perceived by the acoustic transducer 7 as an air vibration or as a pressure pulse.
  • the acoustic pickup 7 is connected to an evaluation circuit S. First, the output signal of the acoustic pickup 7 is fed to a phase comparator 8, which is driven by the oscillator 6 in coincidence with the radiation source 5. It is thus achieved that the signal emitted by the acoustic pickup 7 is only evaluated during the pulse duration of the radiation pulses and is passed on to the downstream threshold value detector 9.
  • this threshold value detector 9 supplies an alarm signal to the signal generator 10 which it controls.
  • Integration or delay elements can be interposed in a known manner, as in the case of other optical fire suppressors, in order to avoid faulty alarm triggers by individual pulses.
  • Known measures for suppressing the transient processes for example in the phase comparator 8, can also be provided in order to avoid disturbing transient impulses.
  • the pulse frequency of the radiation pulses that is to say the frequency of the oscillator 6 and the dimensions of the measuring chamber 1
  • the pulse frequency of the radiation pulses are coordinated with one another in such a way that acoustic waves are generated in the measuring chamber.
  • the deepest cylindrically symmetrical resonance oscillation is 8.2 kHz.
  • Further resonance vibrations with other frequencies can also be excited and used, but are usually somewhat more damped and deliver a correspondingly weaker signal.
  • a substantial amplification of the signal on acoustic pickup 7 can be achieved.
  • the acoustic pickup 7 delivers such a large output signal that it can be evaluated in a simple, interference-free manner. It was therefore possible to choose the measuring chamber dimensions at least an order of magnitude smaller than was customary with extinction fire detectors without the need for a large number of sensitive, precisely adjustable and dust-prone deflection mirrors, as is usual with extinction fire detectors. Nevertheless, the arrangement described can in particular be highly absorbent, i.e. detect black smoke with surprisingly high sensitivity.
  • smoke particles which absorb less strongly and which only cause radiation scattering e.g. Detecting water vapor-containing or white smoke
  • the arrangement can be selected, for example, in accordance with the smoke detectors described in Swiss Patent No. 592932, the radiation source 5 having a cone-shaped radiation characteristic and the radiation receiver 11 being arranged in the cone axis, but outside the direct radiation range.
  • the radiation receiver 11 is shielded from the direct radiation by an aperture system B, for example to keep the radiation scattering at the edges away as a double aperture.
  • This scattered radiation receiver 11 is connected to a further phase comparator 12, likewise controlled by the oscillator 6, which, like the first phase comparator 8, amplifies the incoming signal in coincidence with the radiation pulses and forwards it to a second threshold value detector 13.
  • the threshold value detector 13 now also controls a signal transmitter.
  • This can be the same signal generator 10 as the one that is controlled by the output signals of the acoustic pickup 7, the threshold value detectors of both channels 9 and 13 being connected to the inputs of an OR gate 14 or a corresponding circuit the output of the common fire alarm signal generator 10 is connected.
  • certain signal transmitters or auxiliary devices can also be controlled separately, the triggering of which is expedient depending on the occurrence of a specific type of smoke.
  • a fire extinguishing system 15 can be controlled by the acoustic evaluation channel, which will respond preferably in the case of rapidly spreading fires, while escape route or evacuation display devices 16 can be actuated by the scattered radiation channel, which will respond preferably when white smoke occurs, because of the visual impairment associated therewith .
  • the two additional auxiliary devices 15 or 16 can also be designed as separate signal transmitters in order to be able to recognize in a signal center what type of smoke, i.e. what type of fire is reported. In this way, i.e. H.
  • a universally applicable fire detector can be created, which can detect all types of fire that occur in practice with increased sensitivity and more reliably and quickly, whereby the detector dimensions can be kept extremely small and no risk from the use of radioactive ones Substances can occur.
  • the invention can be further developed by selecting the wavelength of the radiation used in the region of the resonance radiation of a carbon oxide, for example carbon dioxide or carbon monoxide.
  • a semiconductor laser is suitable as the radiation source, which is preferably in the wavelength range of such resonance radiation, for example at 4.7 Jlm, 4.3 pm or 2.7 pm.
  • Three-element laser diodes (three-metal laser diodes) have proven particularly suitable for this purpose, e.g. B. with the composition (Pb 1-x Sn x ) Te or (Pb 1-x Sn x ) Se.
  • Other useful laser diodes are those of Composition Ga (As x P 1-x ) and (Cd x Hg 1-x ) Te, also Pb S Se has proven to be a suitable diode for the generation of radiation in the range of 4-8.5 ⁇ m.
  • the advantage of using radiation of this spectral composition is that it is also absorbed by carbon oxide molecules in the measuring chamber. It was found that when carbon oxide occurs, pressure waves are also generated synchronously with the radiation pulses in the measuring chamber, which are also registered by the acoustic pickup 7. The presence of carbon oxide in the air also triggers a signal. As a fire usually produces carbon oxide in addition to other fire secondary products, this detection of carbon oxide in a fire detector is very desirable anyway.
  • the radiation source is arranged directly in the measuring chamber and is supplied with voltage via an electrical line.
  • the acoustic sensor in the measuring chamber generates an electrical signal, which is also picked up via an electrical line and forwarded to the evaluation unit with a signal circuit.
  • the fire detector shown in FIG. 3 again consists, as in the example according to FIGS. 1 and 2, of a measuring chamber 1 and a measuring device S which is remote from it, for example in a signal center (analog elements are provided with the same reference numerals as in FIGS. 1 and 2). .
  • Measuring chamber and evaluation device are connected to one another by a number of radiation-conducting elements L 1 , L 2 ... L s .
  • These radiation-conducting elements also known as fiber optics or as light guides (for the sake of brevity hereinafter referred to as light guides), can be selected in various ways as required and in coordination with other components of the fire detector.
  • the individual light guides L 1 , L 2 , L s can either consist of a single radiation-guiding element or can also comprise several such elements, for example in the form of light guide bundles.
  • the individual light guides L 1 , L z ... L s which are shown separately in FIG. 1 for the sake of clarity, can be combined in the transmission path between the measuring chamber 1 and the evaluation device S to form a single light guide bundle.
  • a fire alarm system can be created with several measuring points distributed in a protected area. If optical fibers with particularly good transmission properties are selected, transmission lengths that are at least equivalent to those that can be achieved with electrical lines could be achieved, but have the advantage that there is no electrical connection between the measuring chamber and the evaluation device. In addition to the resulting susceptibility to interference, in particular against electrical interference, the measuring chambers can therefore also be accommodated in places where electrical lines are undesirable, in particular in potentially explosive areas.
  • the measuring chamber 1 consists of a cylindrical or slightly conical wall 22, an upper cover 3 and a lower cover 4.
  • the wall 22 is constructed from mutually offset elements, so that the outside air can penetrate into the interior, but light from the Measuring chamber is kept away. Instead, the air to be examined can also be supplied via inlet and outlet openings.
  • One of the light guides L z is introduced into the upper cover 3, via the end X of which electromagnetic radiation, ie visible light, infrared or ultraviolet radiation, is radiated into the chamber.
  • a further light guide L s is inserted into the other cover 4, with the end Y of which radiation is removed from the measuring chamber 1 and returned to the evaluation device S.
  • the exit X of the light guide L 2 and the input Y of the light guide L s are shielded from one another by a system of shutters B, so that the input Y of the light guide L s only receives scattered radiation which originates from smoke particles in the measuring chamber 1.
  • an acoustic-optical converter 17 is arranged, which is connected to the evaluation unit S by further light guides L 3 and L 4 .
  • This acoustic-optical converter 17 has the property of sound Convert vibrations into an optical signal, ie an optical signal fed to the transducer 17 via the light guide L 3 is returned in a changed form via the light guide L 4 by the recorded sound vibrations.
  • the radiation is fed to a radiation source 25 in the signal center S via the light guide L ,, L 2 of the measuring chamber 1.
  • the radiation source 25 is operated in pulses by an oscillator 6 and therefore emits radiation pulses to the light guide L z with a certain pulse frequency, for example in the range between 1 and 20 kHz.
  • the radiation pulses supplied are now absorbed by the smoke and aerosol particles in the measuring chamber 1. These particles heat up briefly and an air pressure wave is generated with each radiation pulse.
  • the pressure pulses of the individual particles add up and can be perceived by the converter 17 as an unmistakable and extraordinarily sensitive sign of the presence of radiation-absorbing particles.
  • the transducer 17 receives radiation from the radiation source 25 via the light guide L 1 and the branch L 3 on the one hand in the same rhythm as the radiation radiated into the measuring chamber 1.
  • the outgoing light guide L 4 of the converter 17 is connected in the evaluation unit S to a radiation sensor 27, the output signal of which is fed to a phase comparator 8, which is also controlled by the oscillator 6 in coincidence with the radiation source 25. This ensures that the optical signal emitted by the converter 17 is evaluated and passed on only during the pulse duration of the radiation pulses.
  • the output signal of the phase comparator 8 is again fed to a threshold value detector 9. As soon as the intensity of the output pulses of the radiation sensor 27 exceeds a certain threshold, this threshold value detector 9 supplies an alarm signal to the signal generator 10 which it controls.
  • the scattered radiation is additionally removed from the measuring chamber via the input Y of the light guide L s and fed to a further radiation sensor 21.
  • This is connected to a further phase comparator 12, likewise controlled by the oscillator 6, which likewise amplifies the incoming signal in coincidence with the radiation pulses and forwards it to a second threshold value detector 13.
  • the threshold value detector 13 controls a signal transmitter.
  • separate signal transmitters or auxiliary devices 15, 16 can also be controlled in each of the two channels.
  • any suitable lamp, a light or infrared-emitting diode or a LASER can be used as the radiation source 25.
  • Fig. 4 shows an acoustic-optical converter which is particularly suitable for operation with a single-mode light guide. It has a housing H, which is closed off by an oscillatable membrane M, so that there is a certain reference pressure inside R. A continuous light guide L 3 , L 4 is attached to the membrane M, for example cemented on. If the membrane M is slightly deformed by the action of sound vibrations, the light guide also bends, the optical transmission properties of which change. This change is particularly striking if a light guide of the monomode type is used and the spectrum of the radiation supplied via the light guide L 3 is matched to its maximum transmission. Depending on the setting, it can be achieved that the permeability either improves or deteriorates with each sound pulse. Accordingly, the evaluation unit must be adapted to the processing of positive or negative radiation inputs.
  • FIG. 5 shows an acoustic-optical converter, which can also be operated with classic or multimode light guides.
  • a housing H is provided with an interior R closed by a membrane M.
  • the membrane M is designed to be reflective or scattering on the outside, so that the radiation supplied via the light guide L 3 is reflected or scattered on the surface and can be absorbed by the light guide L 4 . If the membrane M is deformed as a result of the action of sound vibrations, the amount of radiation absorbed by the light guide L 4 changes, so that here too, any action of sound vibrations or pressure pulses causes a change in the optical signal.
  • FIG. 6 shows an autonomous piezoelectric transducer which contains a piezoelectric element P which is deformable under the action of sound and which emits an electrical charge or voltage in the event of any deformation.
  • the piezoelectric element P is provided with an element with electrically controllable transparency or reflection, e.g. B. a liquid crystal LCD, connected so that the permeability of this element is influenced by the voltage emitted by the piezoelectric element.

Claims (16)

1. Détecteur d'incendie comportant une source de rayonnement (5, 25, Lz) opérant par voie impulsionnelle, dont le rayonnement électromagnétique est transmis dans une chambre de mesure (1) à laquelle a accès l'air qui doit être surveillé du point de vue de l'apparition de particules de fumée et d'aérosol, et un récepteur auquel est reliée une unité d'évaluation (S) qui déclenche un signal d'alarme dès que la valeur du signal émis par le récepteur dépasse un seuil prédéterminé, caractérisé par le fait que le récepteur est un récepteur acoustique (7; 17, L,, 27), qui reçoit une oscillation de l'air produite par les particules par l'absorption des impulsions du rayonnement.
2. Détecteur d'incendie selon la revendication 1, caractérisé par le fait qu'il est prévu un oscillateur électrique (6) qui commande la source de rayonnement de façon impulsionnelle avec une fréquence déterminée des impulsions et commande simultanément, en coïncidence avec des impulsions du rayonnement, un circuit de signalisation (8) dans le circuit d'évaluation (S).
3. Détecteur d'incendie selon la revendication 2, caractérisé par le fait que le circuit de signalisation (8) est un comparateur de phase qui est commandé par l'oscillateur (6) et qui n'évalue que le signal de sortie du récepteur acoustique que pendant sensiblement la durée d'impulsion du rayonnement et il est prévu un détecteur de valeur de seuil (9) fournissant un signal à un générateur de signaux (10) dès que l'intensité du signal de sortie du récepteur dépasse un seuil prédéterminé.
4. Détecteur d'incendie selon l'une des revendications 1-3, caractérisé par le fait que les dimensions de la chambre de mesure (1) sont choisies de telle façon que pour la fréquence des impulsions choisie pour le fonctionnement de la source de rayonnement, des ondes acoustiques stationnaires sont présentes dans la chambre de mesure.
5. Détecteur d'incendie selon la revendication 4, caractérisé par le fait que la fréquence des impulsions de la source de rayonnement se situe entre 1 et 20 kHz, de préférence dans les environs de 8 kHz.
6. Détecteur d'incendie selon l'une des revendications 1-5, caractérisé par le fait qu'il est prévu, en plus, un récepteur de rayonnement diffus (11; Ls, 21) qui reçoit le rayonnement diffusé dans la zone de rayonnement de la source de rayonnement, au niveau des particules de fumées dans la chambre de.mesure (1), mais qui toutefois, ne reçoit aucun rayonnement direct de la source de rayonnement, et qui déclenche un signal dès que l'intensité du rayonnement diffus reçu dépasse un seuil prédéterminé.
7. Détecteur d'incendie selon les revendications 3 et 6, caractérisé par le fait que le récepteur de rayonnement diffus (11; LS, 21) est relié à un circuit d'évaluation qui comporte un second comparateur de phase (12) commandé en coïncidence par l'oscillateur (6), ainsi qu'un second détecteur de valeur de seuil (13) qui commande un générateur de signaux (6) dès que le signal de sortie du récepteur de rayonnement diffus dépasse un seuil prédéterminé.
8. Détecteur d'incendie selon la revendication 7, caractérisé par le fait que le circuit d'évaluation (S) comporte un circuit OU (14) dont les entrées sont attaquées par les deux détecteurs de valeur de seuil (9, 13) et dont les sorties commandent le générateur de signaux (10).
9. Détecteur d'incendie selon la revendication 7, caractérisé par le fait que par les signaux de sortie des détecteurs de valeur de seuil (9, 13) sont susceptibles d'être commandés directement et au choix des appareils auxiliaires (15, 16).
10. Détecteur d'incendie selon l'une des revendications 1-9, caractérisé par le fait que la source de rayonnement (5) émet un rayonnement dans la plage des longueurs d'onde du rayonnement de résonance d'un oxyde de carbone.
11. Détecteur d'incendie selon l'une des revendications 1-10, caractérisé par le fait que la source de rayonnement (25) de même qu'un récepteur de rayonnement (27) sont disposés dans une unité d'évaluation (S), que le rayonnement de la source de rayonnement est guidé, par l'intermédiaire d'éléments de guidage du rayonnement (L" L2, L3) à la chambre de mesure (1) de même qu'au récepteur acoustique, et que le récepteur acoustique comporte un transducteur acousto-optique (17) qui renvoie au récepteur de rayonnement le signal optique éventuellement modifié par les oscillations de l'air, par l'intermédiaire d'au moins un second élément de guidage du rayonnement (L,).
12. Détecteur d'incendie selon la revendication 11, caractérisé par le fait que les éléments de guidage du rayonnement (L1...L4), sont réalisés, en tant que tel, du type monomode.
13. Détecteur d'incendie selon la revendication 12, caractérisé par le fait que le transducteur acousto-optique (17) comporte un élément (M) déformé par les oscillations acoustiques, élément sur lequel sont fixés un élément du guidage de rayonnement (L3) et le second élément de guidage du rayonnement (L,) de manière que leur propriété de transmission optique change lors de la déformation de l'élément déformable (M), par suite d'une déformation simultanée, les deux éléments de guidage du rayonnement (L3, L,) formant ensemble une boucle continue dont une extrémité est reliée à la source de rayonnement (25) et dont l'autre extrémité est reliée au récepteur de rayonnement (27).
14. Détecteur d'incendie selon la revendication 11, caractérisé par le fait que le transducteur acousto-optique (17) comporte un élément (M) mis en vibration par les oscillations acoustiques, et que le rayonnement est dirigé par l'intermédiaire de l'un (L3) des éléments de guidage du rayonnement sur l'élément vibrant alors que le rayonnement réfléchi et diffusé par l'élément vibrant (M) est prélevé du second de guidage du rayonnement (L4) et est envoyé au récepteur de rayonnement (27).
15. Détecteur d'incendie selon la revendication 11, caractérisé par le fait que le transducteur acousto-optique (17) comporte un élément piézo-électrique (P) qui se déforme sous l'action du son et fournit une tension électrique, ainsi qu'un élément (LCD) à transparence électrique susceptible d'être commandée et auquel est appliqué cette tension, ledit élément modifiant, lors de la vibration de l'élément piézo-électrique (P) le signal optique amené par l'intermédiaire de l'un (L3) des éléments de guidage du rayonnement et renvoyé par l'autre (L,) élément de guidage du rayonnement.
16. Détecteur d'incendie selon l'une des revendications 11-15, en liaison avec l'une des revendications 6-9, caractérisé par le fait que dans l'unité d'évaluation (S) est prévu un récepteur de rayonnement supplémentaire (21) qui, par l'intermédiaire d'un élément supplémentaire de guidage de rayonnement (L,), est relié à la chambre de mesure (1) et reçoit à partir de celle-ci le rayonnement diffusé au niveau des particules de fumée et transmet le signal correspondant à l'unité d'évaluation (F).
EP80100508A 1979-02-26 1980-02-01 Détecteur d'incendie à rayonnement pulsé Expired EP0014874B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
CH1867/79 1979-02-26
CH186779A CH641584A5 (de) 1979-02-26 1979-02-26 Brandmelder.
CH1113779 1979-12-17
CH11137/79 1979-12-17

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EP0014874A2 EP0014874A2 (fr) 1980-09-03
EP0014874A3 EP0014874A3 (en) 1980-09-17
EP0014874B1 true EP0014874B1 (fr) 1983-06-08

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DE (1) DE3063643D1 (fr)

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DE102014019172A1 (de) 2014-12-17 2016-06-23 Elmos Semiconductor Aktiengesellschaft Vorrichtung und Verfahren zur Unterscheidung von festen Objekten, Kochdunst und Rauch mit einem kompensierenden optischen Messsystem

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Publication number Priority date Publication date Assignee Title
US3805066A (en) * 1972-08-14 1974-04-16 T Chijuma Smoke detecting device utilizing optical fibers
CH554571A (de) * 1973-08-14 1974-09-30 Cerberus Ag Verfahren und anordnung zur branddetektion.
IL45331A (en) * 1973-11-26 1977-12-30 Chloride Batterijen Bv Photoelectric smoke detector

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102014019773A1 (de) 2014-12-17 2016-06-23 Elmos Semiconductor Aktiengesellschaft Vorrichtung und Verfahren zur Unterscheidung von festen Objekten, Kochdunst und Rauch mittels des Displays eines Mobiltelefons
DE102014019172A1 (de) 2014-12-17 2016-06-23 Elmos Semiconductor Aktiengesellschaft Vorrichtung und Verfahren zur Unterscheidung von festen Objekten, Kochdunst und Rauch mit einem kompensierenden optischen Messsystem

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DE3063643D1 (en) 1983-07-14
EP0014874A3 (en) 1980-09-17
EP0014874A2 (fr) 1980-09-03

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