WO2008017698A1 - Scattered light smoke detector - Google Patents
Scattered light smoke detector Download PDFInfo
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- WO2008017698A1 WO2008017698A1 PCT/EP2007/058255 EP2007058255W WO2008017698A1 WO 2008017698 A1 WO2008017698 A1 WO 2008017698A1 EP 2007058255 W EP2007058255 W EP 2007058255W WO 2008017698 A1 WO2008017698 A1 WO 2008017698A1
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- scattered light
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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
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- the present invention relates to a scattered light smoke detector with a transmitting device for the emission of light of two different wavelengths in a scattering volume and with a receiving device for the selective reception of scattered light of the two wavelengths mentioned.
- Scattered light smoke detectors with light sources which emit differently colored light into the scattering volume are known and described, for example, in EP-A-0 926 646 and 1 408 469. It can be seen from EP-A 0 926 646 that scattered-light smoke detectors with a red transmitter diode have a significantly better and those with a blue transmitter diode a distinctly better response to open fires. The response of such detectors is improved to such an extent that the detection properties for open fires come close to ionization detectors or so-called backward scatterers.
- Backward scatterers are known to be scattered light smoke detectors with a spread angle of over 90 °, the open fires better than forward scatterers, but where the
- Receiver signal only a fraction of the receiver signal from
- Detection of open fires may be due to the fact that at shorter wavelengths smaller aerosols, such as those that occur in open fires, can be detected much better.
- the receiving device is formed by at least one photocell with a wavelength-selective filter having at least two passbands for the wavelengths mentioned.
- the inventive wavelength-selective filter makes it possible to pressurize the scattering volume with light from more than one wavelength while the ambient light ⁇ can totally eliminate.
- a first preferred embodiment of the scattered-light smoke detector according to the invention is characterized in that the one transmission range in the infrared range is 850 nm to 1050 nm and is preferably 880 nm and the other transmission range in the blue range is 330 nm to 430 nm and preferably 430 nm is.
- a second preferred embodiment of the scattered-light smoke detector according to the invention is characterized in that the transmitting device is formed by two light emitting diodes of different wavelengths, which light under two send different angles in the scattering volume, and that the receiving means is formed by a photocell with a dual-band optical filter which receives the scattered light from the scattering volume at a forward and a backward scattering angle.
- a third preferred embodiment of the scattered-light smoke detector according to the invention is characterized in that the transmitting device is formed by a diode emitting light of different wavelengths and the receiving device is formed by a photocell with an optical dual-passband filter.
- Transmitting device by two light of different wavelengths emitting diodes and the receiving device by a
- Photocell is formed with an optical quadruple bandpass filter which receives the scattered light from the scattering volume at a forward and a backward scattering angle.
- a fifth preferred embodiment of the scattered-light smoke detector according to the invention is characterized in that the two diodes of the transmitting device each emit light in different infrared and blue ranges.
- a sixth preferred embodiment of the scattered-light smoke detector according to the invention is characterized in that the passbands of the quadruple-passband filter or filters in a first infrared range of 760 nm to 850 nm, preferably 820 nm, and a second infrared range of 850 nm to 1050 nm, preferably 900 nm and in a first blue range from 330 nm to 430 nm, preferably 380 nm, and a second blue range from 430 nm to 450 nm, preferably 430 nm.
- the passbands of the quadruple-passband filter or filters in a first infrared range of 760 nm to 850 nm, preferably 820 nm, and a second infrared range of 850 nm to 1050 nm, preferably 900 nm and in a first blue range from 330 nm to 430 nm, preferably 380 nm
- FIG. 1 shows a schematic cross section through the optical measuring chamber of a first embodiment of an inventive scattered light smoke detector.
- FIG. 2 shows a schematic cross section through the optical measuring chamber of a second and a third embodiment of an inventive
- FIG 3 shows a schematic cross section through the optical measuring chamber of a fourth exemplary embodiment of a scattered-light smoke detector according to the invention.
- the reference numeral 1 denotes the side wall of the optical measuring chamber of a scattered light smoke detector, which is formed for example by a so-called labyrinth.
- a scattering volume 2 which is shielded from external light by the said labyrinth is formed from the outside.
- Stray light smoke detectors and their optical measuring chamber are set as known advance, it is in this context to EP-A-O 772 170, 1 017 034 and 1 376 504, the disclosure of which is hereby incorporated by reference.
- two light sources 3 and 4 are arranged at the periphery of the measuring chamber, preferably by light-emitting diodes
- LED are formed, of which the light source 3 blue light in the near-ultraviolet to early blue wavelength range of preferably about 430 nm and the light source 4 near-infrared light of preferably about 880 nm in the
- Measuring chamber is arranged a photoreceiver 5, in front of which a wavelength-selective optical filter 6 is placed.
- this only transmits radiation with the wavelengths emitted by the two light sources 3 and 4, and on the other hand makes no or only very little radiation pass in the region of the ambient light from the blue to the near-infrared wavelength range.
- the wavelength-selective filter 6 is referred to below as a dual-passband filter, the term passband denoting that wavelength range of the optical spectrum in which the filter allows the light to pass unhindered or almost unhindered.
- a dual-passband filter instead of two light sources and one dual-passband filter, three light sources with a triple-passband optical filter or four light sources with a quadruple-passband optical filter and so on can also be combined.
- the dual-passband filter 6 not only saves a second photoreceiver but has the particular advantage that the shielding of light unwanted wavelengths such as ambient light, the basic pulse is very small and the electronic gain can be very high. Even the smallest smoke densities can be detected reliably and their origin can be clearly divided into fire or non-fire. Due to the sensitive smoke detection, the light sources require less energy, which is a significant advantage for battery operated smoke detectors.
- the photoreceptor 5 is arranged relative to the light sources 3 and 4 so that no light emitted from these to the
- Photoreceptor 5 passes as long as no aerosol in
- the amount of this scattered light is a measure of the number of particles in the scattering volume 2 or in other words, the smoke density.
- Fig. 1 is located between the light emitted by the light source 3 and dashed blue radiation and received by the photoreceptor 5 and also shown in dashed blue scattered light a sharp and between the light emitted by the light source 4 infrared radiation and the photoreceptor. 5 received corresponding stray light an obtuse angle.
- the blue radiation of the light source 3 is thus scattered backwards on the photoreceptor 5 and the infrared radiation of the light source 4 is scattered forward on the photoreceiver 5.
- the evaluation of the backward scattering and the use of blue light both significantly increase the response of the detector to open fires.
- Fig. 2 two variants of another embodiment of a scattered light smoke detector are shown.
- two 2-color light sources 7 and 8 ie actually four light sources, are provided.
- Each of the two 2-color light sources 7 and 8 emits light in the infrared and in the blue range, but in the two light sources 7 and 8, the wavelengths are not equal.
- the light source 7 emits blue light of wavelength 430 nm and infrared radiation of wavelength 880 nm and the light source 8 blue light of wavelength 370 nm and infrared radiation of wavelength 980 nm.
- the front of the photoreceptor 5 arranged optical filter is in the embodiment of FIG
- the two 2-color light sources 7, 8 and the Quadrupelpassband filter 9 is a further reduction of the fundamental pulse so that very small smoke densities recorded and fire already in the Initial stage can be detected.
- a second photoreceiver 10 is provided with an upstream optical quadruple passband filter 11, which is also provided by that of the two 2-color light sources 7 and 8 received light emitted stray light receives.
- the scattered light smoke detector of this second variant thus uses two 2-color light sources 7 and 8 which emit light of different wavelengths, which corresponds to four light sources with different light sources and two photoreceivers 5 and 10 with optical quadruple passband filters 9 and 11, respectively
- two polarizing filters 12 and 13 are provided, which are arranged either between light source 7, 8 and scattering space 2 or, as shown, between scattering space 2 and the photoreceptors 5 and 10, respectively.
- the polarizing filters 12 and 13 which of the light emitted from the light sources 7 and 8 and scattered on the particles present in the scattering space 2, pass only that portion which vibrates in a certain direction of polarization.
- the polarizing filters 12 and 13 are wavelength independent and thus allow all light to pass whose wavelength is in the range of ultraviolet to near infrared.
- the polarization filters allow an even more accurate determination of the type of smoke.
- FIG. 3 shows an optical scattered-light smoke detector with a 2-color light source 7 which emits blue light of wavelength 430 nm and infrared radiation of wavelength 880 nm, and with a photoreceiver 5 with upstream dual-passband filter 6.
- the basic pulse is very small and thus the gain of the electronic circuit can be chosen very high, which allows a very sensitive smoke detection.
- the different types of smoke can be distinguished very well. Because the smoke detection is so sensitive, much less electrical power is needed to power the light sources than before.
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Abstract
Description
Beschreibungdescription
Streulicht-RauchmelderScattered light smoke detector
Die vorliegende Erfindung betrifft einen Streulicht- Rauchmelder mit einer Sendeeinrichtung für die Aussendung von Licht zweier unterschiedlicher Wellenlängen in ein Streuvolumen und mit einer Empfangseinrichtung für den selektiven Empfang von Streulicht der beiden genannten Wellenlängen.The present invention relates to a scattered light smoke detector with a transmitting device for the emission of light of two different wavelengths in a scattering volume and with a receiving device for the selective reception of scattered light of the two wavelengths mentioned.
Streulicht-Rauchmelder mit Lichtquellen, welche verschieden farbiges Licht in das Streuvolumen aussenden, sind bekannt und beispielsweise in den EP-A-O 926 646 und 1 408 469 beschrieben. Der EP-A 0 926 646 ist zu entnehmen, dass Streulicht-Rauchmelder mit einer roten Sender-Diode ein deutlich besseres und solche mit einer blauen Sender-Diode ein markant besseres Ansprechverhalten auf offene Brände aufweisen. Das Ansprechverhalten solcher Melder wird so weit verbessert, dass die Detektionseigenschaften für offene Brände in die Nähe von Ionisationsmeldern oder von so genannten Rückwärtsstreuern gelangen.Scattered light smoke detectors with light sources which emit differently colored light into the scattering volume are known and described, for example, in EP-A-0 926 646 and 1 408 469. It can be seen from EP-A 0 926 646 that scattered-light smoke detectors with a red transmitter diode have a significantly better and those with a blue transmitter diode a distinctly better response to open fires. The response of such detectors is improved to such an extent that the detection properties for open fires come close to ionization detectors or so-called backward scatterers.
Rückwärtsstreuer sind bekanntlich Streulicht-Rauchmelder mit einem Streuwinkel von über 90°, die offene Brände besser erkennen als Vorwärtsstreuer, bei denen aber dasBackward scatterers are known to be scattered light smoke detectors with a spread angle of over 90 °, the open fires better than forward scatterers, but where the
Empfängersignal nur einen Bruchteil des Empfängersignals vonReceiver signal only a fraction of the receiver signal from
Vorwärtsstreuern beträgt. Der Grund für diese verbesserteForward scattering is. The reason for this improved
Detektion von offenen Bränden dürfte darin liegen, dass bei kürzeren Wellenlängen kleinere Aerosole, wie sie vor allem bei offenen Bränden entstehen, sehr viel besser detektiert werden können.Detection of open fires may be due to the fact that at shorter wavelengths smaller aerosols, such as those that occur in open fires, can be detected much better.
Bei dem in der EP-A-I 408 469 beschriebene Rauchmelder wird in das Streuvolumen zusätzlich zu einer Infrarot-Strahlung blaues Licht eingestrahlt und es werden die an den Partikeln im Streuvolumen entstehenden Streustrahlungen sowohl im Vorwärts- als auch im Rückwärts-Streubereich im infaroten und blauen Bereich getrennt voneinander gemessen und ausgewertet.In the smoke detector described in EP-AI 408 469, blue light is radiated into the scattering volume in addition to an infrared radiation, and the scattered radiation arising on the particles in the scattering volume becomes both in the Measured forward and in the backward scattering area in the infar and blue area separated and evaluated.
Beide bekannten Streulicht-Rauchmelder sind auf Umgebungs- licht relativ empfindlich, was zu einem hohen Grundpuls führt, der wiederum bewirkt, dass kleine Unterschiede vonBoth known scattered-light smoke detectors are relatively sensitive to ambient light, which leads to a high fundamental pulse, which in turn causes small differences of
Streulicht in Vorwärts- und Rückwärts-Streuung nicht eindeutig gemessen und somit zum Beispiel Rauch aus Feuer undScattered light in forward and backward scattering not clearly measured and thus, for example, smoke from fire and
Wassernebel oder Rauch aus Feuer und Schweissen nicht sicher unterschieden werden können.Water mist or smoke from fire and welding can not be safely distinguished.
Durch die Erfindung soll nun ein Streulicht-Rauchmelder angegeben werden, welcher eine eindeutige Unterscheidung von Rauch aus Feuer und anderen nicht durch Feuer verursachten Aerosolen ermöglicht.By the invention, a scattered light smoke detector will now be given, which allows a clear distinction of smoke from fire and other aerosols not caused by fire.
Die gestellte Aufgabe wird erfindungsgemäss dadurch gelöst, dass die Empfangseinrichtung durch mindestens eine Fotozelle mit einem wellenlängenselektiven Filter mit mindestens zwei Durchlassbereichen für die genannten Wellenlängen gebildet ist .The object is achieved according to the invention in that the receiving device is formed by at least one photocell with a wavelength-selective filter having at least two passbands for the wavelengths mentioned.
Der erfindungsgemässe wellenlängenselektive Filter macht es möglich, dass man das Streuvolumen mit Licht von mehr als einer Wellenlänge beaufschlagen und trotzdem das Umgebungs¬ licht völlig eliminieren kann.The inventive wavelength-selective filter makes it possible to pressurize the scattering volume with light from more than one wavelength while the ambient light ¬ can totally eliminate.
Eine erste bevorzugte Ausführungsform des erfindungsgemässen Streulicht-Rauchmelders ist dadurch gekennzeichnet, dass der eine Durchlassbereich im Infrarotbereich von 850 nm bis 1050 nm liegt und vorzugsweise 880 nm beträgt, und dass der andere Durchlassbereich im Blaubereich von 330 nm bis 430 nm liegt und vorzugsweise 430 nm beträgt.A first preferred embodiment of the scattered-light smoke detector according to the invention is characterized in that the one transmission range in the infrared range is 850 nm to 1050 nm and is preferably 880 nm and the other transmission range in the blue range is 330 nm to 430 nm and preferably 430 nm is.
Eine zweite bevorzugte Ausführungsform des erfindungsgemässen Streulicht-Rauchmelders ist dadurch gekennzeichnet, dass die Sendeeinrichtung durch zwei Licht verschiedener Wellenlängen aussendende Dioden gebildet ist, welche Licht unter zwei verschiedenen Winkeln in das Streuvolumen senden, und dass die Empfangseinrichtung durch eine Fotozelle mit einem optischen Dualpassband-Filter gebildet ist, welche das Streulicht aus dem Streuvolumen unter einem Vorwärts- und einem Rückwärts-Streuwinkel empfängt.A second preferred embodiment of the scattered-light smoke detector according to the invention is characterized in that the transmitting device is formed by two light emitting diodes of different wavelengths, which light under two send different angles in the scattering volume, and that the receiving means is formed by a photocell with a dual-band optical filter which receives the scattered light from the scattering volume at a forward and a backward scattering angle.
Eine dritte bevorzugte Ausführungsform des erfindungsgemässen Streulicht-Rauchmelders ist dadurch gekennzeichnet, dass die Sendeeinrichtung durch eine Licht verschiedener Wellenlängen aussendende Diode und die Empfangseinrichtung durch eine Fotozelle mit einem optischen Dualpassband-Filter gebildet ist .A third preferred embodiment of the scattered-light smoke detector according to the invention is characterized in that the transmitting device is formed by a diode emitting light of different wavelengths and the receiving device is formed by a photocell with an optical dual-passband filter.
Eine vierte bevorzugte Ausführungsform des erfindungsgemässen Streulicht-Rauchmelders ist dadurch gekennzeichnet, dass dieA fourth preferred embodiment of the inventive scattered light smoke detector is characterized in that the
Sendeeinrichtung durch zwei Licht verschiedener Wellenlängen aussendende Dioden und die Empfangseinrichtung durch eineTransmitting device by two light of different wavelengths emitting diodes and the receiving device by a
Fotozelle mit einem optischen Quadrupelpassband-Filter gebildet ist, welche das Streulicht aus dem Streuvolumen unter einem Vorwärts- und einem Rückwärts-Streuwinkel empfängt .Photocell is formed with an optical quadruple bandpass filter which receives the scattered light from the scattering volume at a forward and a backward scattering angle.
Eine fünfte bevorzugte Ausführungsform des erfindungsgemässen Streulicht-Rauchmelders ist dadurch gekennzeichnet, dass die beiden Dioden der Sendeeinrichtung jeweils Licht in verschiedenen Infrarot- und Blaubereichen aussenden.A fifth preferred embodiment of the scattered-light smoke detector according to the invention is characterized in that the two diodes of the transmitting device each emit light in different infrared and blue ranges.
Eine sechste bevorzugte Ausführungsform des erfindungs- gemässen Streulicht-Rauchmelders ist dadurch gekennzeichnet, dass die Durchlassbereiche des oder der Quadrupelpassband- Filter in einem ersten Infrarotbereich von 760 nm bis 850 nm, vorzugsweise 820 nm, und einem zweiten Infrarotbereich von 850 nm bis 1050 nm, vorzugsweise 900 nm und in einem ersten Blaubereich von 330 nm bis 430 nm, vorzugsweise 380 nm, und einem zweiten Blaubereich von 430 nm bis 450 nm, vorzugsweise 430 nm, liegen. Im Folgenden wird die Erfindung anhand von Ausführungs¬ beispielen und der Zeichnungen näher erläutert; es zeigt:A sixth preferred embodiment of the scattered-light smoke detector according to the invention is characterized in that the passbands of the quadruple-passband filter or filters in a first infrared range of 760 nm to 850 nm, preferably 820 nm, and a second infrared range of 850 nm to 1050 nm, preferably 900 nm and in a first blue range from 330 nm to 430 nm, preferably 380 nm, and a second blue range from 430 nm to 450 nm, preferably 430 nm. In the following, the invention will be explained in more detail with reference to exemplary ¬ examples and the drawings; it shows:
Fig. 1 einen schematischen Querschnitt durch die optische Messkammer eines ersten Ausführungsbeispiels eines erfindungsgemässen Streulicht-Rauchmelders;1 shows a schematic cross section through the optical measuring chamber of a first embodiment of an inventive scattered light smoke detector.
Fig. 2 einen schematischen Querschnitt durch die optische Messkammer eines zweiten und eines dritten Ausführungsbeispiels eines erfindungsgemässen2 shows a schematic cross section through the optical measuring chamber of a second and a third embodiment of an inventive
Streulicht-Rauchmelders; undScattered light smoke detector; and
Fig. 3 einen schematischen Querschnitt durch die optische Messkammer eines vierten Ausführungsbeispiels eines erfindungsgemässen Streulicht-Rauchmelders.3 shows a schematic cross section through the optical measuring chamber of a fourth exemplary embodiment of a scattered-light smoke detector according to the invention.
In den Figuren ist mit dem Bezugszeichen 1 die Seitenwand der optischen Messkammer eines Streulicht-Rauchmelders bezeichnet, die beispielsweise durch ein so genanntes Labyrinth gebildet ist. In einem zentralen Bereich der Messkammer ist ein durch das genannte Labyrinth gegen Fremdlicht von aussen abgeschirmtes Streuvolumen 2 gebildet. Streulicht-Rauchmelder und deren optische Messkammer werden als bekannt voraus gesetzt, es wird in diesem Zusammenhang auf die EP-A-O 772 170, 1 017 034 und 1 376 504 verwiesen, auf deren Offenbarung hiermit ausdrücklich Bezug genommen wird.In the figures, the reference numeral 1 denotes the side wall of the optical measuring chamber of a scattered light smoke detector, which is formed for example by a so-called labyrinth. In a central region of the measuring chamber, a scattering volume 2 which is shielded from external light by the said labyrinth is formed from the outside. Stray light smoke detectors and their optical measuring chamber are set as known advance, it is in this context to EP-A-O 772 170, 1 017 034 and 1 376 504, the disclosure of which is hereby incorporated by reference.
Bei dem in Fig. 1 dargestellten Ausführungsbeispiel sind an der Peripherie der Messkammer zwei Lichtquellen 3 und 4 angeordnet, die vorzugsweise durch Licht emittierende DiodenIn the embodiment shown in Fig. 1, two light sources 3 and 4 are arranged at the periphery of the measuring chamber, preferably by light-emitting diodes
(LED) gebildet sind, von denen die Lichtquelle 3 blaues Licht im nahen ultravioletten bis Anfang blauen Wellenlängenbereich von vorzugsweise etwa 430 nm und die Lichtquelle 4 Licht im nahen Infrarotbereich von vorzugsweise etwa 880 nm in das(LED) are formed, of which the light source 3 blue light in the near-ultraviolet to early blue wavelength range of preferably about 430 nm and the light source 4 near-infrared light of preferably about 880 nm in the
Streuvolumen 2 aussendet. Ebenfalls an der Peripherie derScatter volume 2 sends out. Also on the periphery of the
Messkammer ist ein Fotoempfänger 5 angeordnet, vor dem ein wellenlängen-selektiver optischer Filter 6 platziert ist. Dieser lässt einerseits nur Strahlung mit den Wellenlängen durch, die von den beiden Lichtquellen 3 und 4 emittiert werden, und lässt andererseits im Bereich des Umgebungslichts vom blauen bis Anfang nahen infraroten Wellenlängenbereich keine oder nur sehr wenig Strahlung passieren.Measuring chamber is arranged a photoreceiver 5, in front of which a wavelength-selective optical filter 6 is placed. On the one hand, this only transmits radiation with the wavelengths emitted by the two light sources 3 and 4, and on the other hand makes no or only very little radiation pass in the region of the ambient light from the blue to the near-infrared wavelength range.
Der wellenlängenselektive Filter 6 wird im Folgenden als Dualpassband-Filter bezeichnet, wobei der Ausdruck Passband jenes Wellenlängengebiet des optischen Spektrums bezeichnet, in welchem der Filter das Licht ungehindert oder beinahe ungehindert passieren lässt. Anstatt von zwei Lichtquellen und einem Dualpassband-Filter können auch drei Lichtquellen mit einem optischen Tripelpassband-Filter oder vier Lichtquellen mit einem optischen Quadrupelpassband-Filter und so weiter kombiniert werden.The wavelength-selective filter 6 is referred to below as a dual-passband filter, the term passband denoting that wavelength range of the optical spectrum in which the filter allows the light to pass unhindered or almost unhindered. Instead of two light sources and one dual-passband filter, three light sources with a triple-passband optical filter or four light sources with a quadruple-passband optical filter and so on can also be combined.
Der Dualpassband-Filter 6 erspart nicht nur einen zweiten Fotoempfänger sondern hat vor allem den Vorteil, dass durch die Abschirmung von Licht ungewollter Wellenlängen wie zum Beispiel Umgebungslicht, der Grundpuls sehr klein wird und die elektronische Verstärkung sehr hoch gewählt werden kann. Damit können auch schon kleinste Rauchdichten zuverlässig detektiert und ihre Herkunft kann eindeutig in Feuer oder Nicht-Feuer eingeteilt werden. Aufgrund des empfindlichen Rauchnachweises benötigen die Lichtquellen weniger Energie, was für Batterie betriebene Rauchmelder ein wesentlicher Vorteil ist.The dual-passband filter 6 not only saves a second photoreceiver but has the particular advantage that the shielding of light unwanted wavelengths such as ambient light, the basic pulse is very small and the electronic gain can be very high. Even the smallest smoke densities can be detected reliably and their origin can be clearly divided into fire or non-fire. Due to the sensitive smoke detection, the light sources require less energy, which is a significant advantage for battery operated smoke detectors.
Der Fotoempfänger 5 ist relativ zu den Lichtquellen 3 und 4 so angeordnet, dass kein von diesen ausgesandtes Licht an denThe photoreceptor 5 is arranged relative to the light sources 3 and 4 so that no light emitted from these to the
Fotoempfänger 5 gelangt, solange sich kein Aerosol imPhotoreceptor 5 passes as long as no aerosol in
Streuvolumen 2 befindet. Sobald sich Aerosol im StreuvolumenScatter volume 2 is located. Once aerosol in the scatter volume
2 befindet, wird das von den Lichtquellen 3, 4 ausgesandte2, the emitted from the light sources 3, 4
Licht an den Aerosolpartikeln gestreut, so dass Streulicht an den Fotoempfänger 5 gelangt. Die Menge dieses Streulichts ist ein Mass für die Anzahl von Partikeln im Streuvolumen 2 oder mit anderen Worten, für die Rauchdichte. Wie aus Fig. 1 zu entnehmen ist, liegt zwischen der von der Lichtquelle 3 ausgesandten und gestrichelt eingezeichneten blauen Strahlung und dem vom Fotoempfänger 5 empfangenen und ebenfalls gestrichelt eingezeichneten blauen Streulicht ein spitzer und zwischen der von der Lichtquelle 4 ausgesandten Infrarotstrahlung und dem vom Fotoempfänger 5 empfangenen entsprechenden Streulicht ein stumpfer Winkel. Die blaue Strahlung der Lichtquelle 3 wird also auf den Fotoempfänger 5 rückwärts gestreut und die Infrarotstrahlung der Lichtquelle 4 wird auf den Fotoempfänger 5 vorwärts gestreut. Die Auswertung der Rückwärtsstreuung und die Verwendung von blauem Licht erhöhen beide das Ansprechverhalten des Melders auf offene Brände markant.Light scattered on the aerosol particles, so that stray light reaches the photoreceptor 5. The amount of this scattered light is a measure of the number of particles in the scattering volume 2 or in other words, the smoke density. As can be seen from Fig. 1, is located between the light emitted by the light source 3 and dashed blue radiation and received by the photoreceptor 5 and also shown in dashed blue scattered light a sharp and between the light emitted by the light source 4 infrared radiation and the photoreceptor. 5 received corresponding stray light an obtuse angle. The blue radiation of the light source 3 is thus scattered backwards on the photoreceptor 5 and the infrared radiation of the light source 4 is scattered forward on the photoreceiver 5. The evaluation of the backward scattering and the use of blue light both significantly increase the response of the detector to open fires.
In Fig. 2 sind zwei Varianten eines weiteren Ausführungsbeispiels eines Streulicht-Rauchmelders dargestellt. Bei der ersten, mit voll ausgezogenen Linien dargestellten Variante sind zwei 2-Farben Lichtquellen 7 und 8, also eigentlich vier Lichtquellen vorgesehen. Jede der beiden 2-Farben Lichtquellen 7 und 8 sendet Licht im Infrarot- und im Blaubereich aus, wobei aber bei den beiden Lichtquellen 7 und 8 die Wellenlängen nicht gleich sind. Beispielsweise sendet die Lichtquelle 7 blaues Licht der Wellenlänge 430 nm und Infrarotstrahlung der Wellenlänge 880 nm aus und die Lichtquelle 8 blaues Licht der Wellenlänge 370 nm und Infrarotstrahlung der Wellenlänge 980 nm. Der vor dem Fotoempfänger 5 angeordnete optische Filter ist beim Ausführungsbeispiel von Fig. 2 nicht mehr ein Dualpassband- sondern ein Quadrupel-passband-Filter 9. Durch die Verwendung der beiden 2-Farben-Lichtquellen 7, 8 und des Quadrupelpassband-Filters 9 erfolgt eine weitere Senkung des Grundpulses, so dass sehr kleine Rauchdichten erfasst und Feuer schon im Anfangsstadium detektiert werden können.In Fig. 2, two variants of another embodiment of a scattered light smoke detector are shown. In the first variant shown with solid lines, two 2-color light sources 7 and 8, ie actually four light sources, are provided. Each of the two 2-color light sources 7 and 8 emits light in the infrared and in the blue range, but in the two light sources 7 and 8, the wavelengths are not equal. For example, the light source 7 emits blue light of wavelength 430 nm and infrared radiation of wavelength 880 nm and the light source 8 blue light of wavelength 370 nm and infrared radiation of wavelength 980 nm. The front of the photoreceptor 5 arranged optical filter is in the embodiment of FIG By using the two 2-color light sources 7, 8 and the Quadrupelpassband filter 9 is a further reduction of the fundamental pulse so that very small smoke densities recorded and fire already in the Initial stage can be detected.
Bei der zweiten gepunktet eingezeichneten Variante ist ein zweiter Fotoempfänger 10 mit einem vorgeschalteten optischen Quadrupel-passband-Filter 11 vorgesehen, welcher ebenfalls von dem von den beiden 2-Farben-Lichtquellen 7 und 8 ausgesandten Licht stammendes Streulicht empfängt. Der Streulicht-Rauchmelder dieser zweiten Variante verwendet also zwei 2-Farben-Lichtquellen 7 und 8, die je Licht unterschiedlicher Wellenlängen aussenden, was also vier Lichtquellen mit verschiedenen Lichtquellen entspricht und zwei Fotoempfänger 5 und 10 mit optischem Quadrupel-passband- Filter 9 beziehungsweise 11. Ausserdem sind noch zwei Polarisationsfilter 12 und 13 vorgesehen, die entweder zwischen Lichtquelle 7, 8 und Streuraum 2 oder, so wie dargestellt, zwischen Streuraum 2 und den Fotoempfängern 5 beziehungsweise 10 angeordnet sind. Die Polarisationsfilter 12 und 13, welche von dem Licht, das von den Lichtquellen 7 und 8 ausgestrahlt und an dem im Streuraum 2 vorhandenen Partikeln gestreut wird, nur jenen Anteil passieren, der in einer bestimmten Polarisationsrichtung schwingt. Die Polarisationsfilter 12 und 13 sind Wellenlängen unabhängig und lassen somit alles Licht passieren, dessen Wellenlänge im Bereich von Ultraviolett bis ins nahe Infrarot liegt. Die Polarisationsfilter ermöglichen eine noch genauere Bestimmung des Rauchtyps.In the second dotted-marked variant, a second photoreceiver 10 is provided with an upstream optical quadruple passband filter 11, which is also provided by that of the two 2-color light sources 7 and 8 received light emitted stray light receives. The scattered light smoke detector of this second variant thus uses two 2-color light sources 7 and 8 which emit light of different wavelengths, which corresponds to four light sources with different light sources and two photoreceivers 5 and 10 with optical quadruple passband filters 9 and 11, respectively In addition, two polarizing filters 12 and 13 are provided, which are arranged either between light source 7, 8 and scattering space 2 or, as shown, between scattering space 2 and the photoreceptors 5 and 10, respectively. The polarizing filters 12 and 13, which of the light emitted from the light sources 7 and 8 and scattered on the particles present in the scattering space 2, pass only that portion which vibrates in a certain direction of polarization. The polarizing filters 12 and 13 are wavelength independent and thus allow all light to pass whose wavelength is in the range of ultraviolet to near infrared. The polarization filters allow an even more accurate determination of the type of smoke.
Das in Fig. 3 dargestellte Ausführungsbeispiel zeigt einen optischen Streulicht-Rauchmelder mit einer 2-Farben- Lichtquelle 7, welche blaues Licht der Wellenlänge 430 nm und Infrarotstrahlung der Wellenlänge 880 nm aussendet, und mit einem Fotoempfänger 5 mit vorgeschaltetem Dualpassband- Filter 6.The exemplary embodiment illustrated in FIG. 3 shows an optical scattered-light smoke detector with a 2-color light source 7 which emits blue light of wavelength 430 nm and infrared radiation of wavelength 880 nm, and with a photoreceiver 5 with upstream dual-passband filter 6.
Die dargestellten optischen Streulicht-Rauchmelder haben gegenüber den aus dem Stand der Technik bekannten die folgenden Vorteile:The illustrated scattered light optical smoke detectors have the following advantages over those known from the prior art:
Der Grundpuls ist sehr klein und damit kann die Verstärkung der elektronischen Schaltung sehr hoch gewählt werden, was einen sehr empfindlichen Rauchnachweis ermöglicht. Die verschiedenen Raucharten können sehr gut unterschieden werden . Weil der Rauchnachweis so empfindlich ist, wird für die Speisung der Lichtquellen sehr viel weniger elektrische Leistung benötigt als bisher.The basic pulse is very small and thus the gain of the electronic circuit can be chosen very high, which allows a very sensitive smoke detection. The different types of smoke can be distinguished very well. Because the smoke detection is so sensitive, much less electrical power is needed to power the light sources than before.
Wenn auch noch Polarisationsfilter eingesetzt werden, kann der Rauchtyp noch genauer bestimmt werden und die Unterscheidung von Feuer und nicht Feuer wird noch eindeutiger . Even if polarizing filters are used, the type of smoke can be more accurately determined and the distinction between fire and not fire becomes even clearer.
Claims
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP06118673A EP1887536A1 (en) | 2006-08-09 | 2006-08-09 | Smoke alarm using light scattering |
| EP06118673.0 | 2006-08-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2008017698A1 true WO2008017698A1 (en) | 2008-02-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/EP2007/058255 Ceased WO2008017698A1 (en) | 2006-08-09 | 2007-08-09 | Scattered light smoke detector |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP1887536A1 (en) |
| WO (1) | WO2008017698A1 (en) |
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| DE102011108390A1 (en) | 2011-07-22 | 2013-01-24 | PPP "KB Pribor" Ltd. | Method of making an open type smoke detector and smoke detector |
| WO2016206000A1 (en) * | 2015-06-23 | 2016-12-29 | 华中科技大学 | Method of sensing aerosol characteristic parameter using dual-wavelength scattered signal and application thereof |
| CN112885025A (en) * | 2021-03-11 | 2021-06-01 | 中国科学技术大学 | Single-wavelength light source and double-scattering-angle electrolyte fire and smoke detection device and method |
| CN113508288A (en) * | 2018-09-28 | 2021-10-15 | 西门子瑞士有限公司 | Scattered light smoke detector with wavelength selective polarizer and suitable use of such a polarizer |
| CN113670786A (en) * | 2021-10-21 | 2021-11-19 | 中国民航大学 | A dual-wavelength fire smoke detection system and method based on lock-in amplification |
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| EP3494561B1 (en) | 2016-08-04 | 2021-09-29 | Carrier Corporation | Smoke detector |
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| EP3321905B1 (en) * | 2016-11-11 | 2022-10-12 | Kidde Technologies, Inc. | High sensitivity fiber optic based detection |
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| DE102011108389A1 (en) | 2011-07-22 | 2013-01-24 | PPP "KB Pribor" Ltd. | smoke detector |
| DE102011108390A1 (en) | 2011-07-22 | 2013-01-24 | PPP "KB Pribor" Ltd. | Method of making an open type smoke detector and smoke detector |
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| CN113508288A (en) * | 2018-09-28 | 2021-10-15 | 西门子瑞士有限公司 | Scattered light smoke detector with wavelength selective polarizer and suitable use of such a polarizer |
| CN112885025A (en) * | 2021-03-11 | 2021-06-01 | 中国科学技术大学 | Single-wavelength light source and double-scattering-angle electrolyte fire and smoke detection device and method |
| CN113670786A (en) * | 2021-10-21 | 2021-11-19 | 中国民航大学 | A dual-wavelength fire smoke detection system and method based on lock-in amplification |
| CN114758469A (en) * | 2022-06-13 | 2022-07-15 | 深圳市派安科技有限公司 | Fire smoke detection alarm capable of resisting ambient light interference |
| CN114758469B (en) * | 2022-06-13 | 2022-09-02 | 深圳市派安科技有限公司 | Fire smoke detection alarm capable of resisting ambient light interference |
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