EP0079011B1 - Smoke detector - Google Patents

Smoke detector Download PDF

Info

Publication number
EP0079011B1
EP0079011B1 EP82110014A EP82110014A EP0079011B1 EP 0079011 B1 EP0079011 B1 EP 0079011B1 EP 82110014 A EP82110014 A EP 82110014A EP 82110014 A EP82110014 A EP 82110014A EP 0079011 B1 EP0079011 B1 EP 0079011B1
Authority
EP
European Patent Office
Prior art keywords
radiation
smoke detector
diaphragm
receiver
solid angle
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
EP82110014A
Other languages
German (de)
French (fr)
Other versions
EP0079011A1 (en
Inventor
Jürg Dr. sc. nat. Dipl.-Phys. Muggli
Peter Gruber
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cerberus AG
Original Assignee
Cerberus AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cerberus AG filed Critical Cerberus AG
Priority to AT82110014T priority Critical patent/ATE17061T1/en
Publication of EP0079011A1 publication Critical patent/EP0079011A1/en
Application granted granted Critical
Publication of EP0079011B1 publication Critical patent/EP0079011B1/en
Expired legal-status Critical Current

Links

Images

Classifications

    • 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 is based on a smoke detector operating according to the scattered radiation principle of the type defined in the preamble of claim 1.
  • Such a smoke detector is known for example from US-A-3 992 102.
  • the scattered light smoke detector described there has a cylindrical smoke chamber.
  • the light source and receiver are located approximately on the periphery of the cylinder and the sensitivity is adjusted using an adjusting screw located in the middle of the beam path at the top of a plate that prevents the receiver from being directly irradiated by the light source.
  • By turning the adjusting screw in not only the amount of light falling into the measuring room and the size of the room visible to the receiver are changed, but also (due to the scattering on the adjusting screw) the light scattered into the measuring room in the absence of smoke.
  • the smoke detector has the advantage that the amount of light emitted by the light source and the amount of light received by the receiver can be adjusted with a single setting device. At the same time, however, it must be accepted that the signal-to-noise ratio is adversely affected by an increase in the scattered light. Due to the arrangement of the adjusting screw in the middle of the beam path, the adjustment is not very
  • a smoke detector is known from CH-A-592 932, in which the radiation source emits the light in a conical shape and the receiver sees a hollow-conical solid angle.
  • the smoke detector contains an evaluation circuit which triggers an alarm when a predetermined signal level of the received scattered light is reached.
  • the smoke concentration at which the alarm is triggered is fixed.
  • the sensitivity setting for adaptation to different environmental conditions can also be achieved, for example, by changing the alarm threshold.
  • an electrical circuit arrangement for changing the sensitivity was proposed in CH-PS 468 683, in which the setting of the response threshold of a field effect transistor serving as an amplifier and threshold value detector takes place by means of a potentiometer, which is part of a voltage divider with which the source electrode is biased. Even if the setting is not made continuously with the potentiometer, but by means of a switch with which fixed resistors of different sizes are switched into the circuit, such electrical setting options are prone to failure and are not corrosion-resistant.
  • the invention has for its object to provide a smoke detector which does not have the disadvantages of the known smoke detectors mentioned and in particular to provide an optical smoke detector, the sensitivity of which can be changed in a defined manner by purely mechanical modification of optical parts.
  • the spatial angle visible by the radiation receiver is narrowed by a diaphragm which is arranged directly in front of the radiation receiver and can be displaced along the radiation direction.
  • the light falling from the radiation source onto the reference cell is narrowed by changing the opening in the aperture in front of the reference cell.
  • the radiation source 1 e.g. a semiconductor element emitting IR radiation, in the lower part of the detector.
  • the IR radiation is bundled in a hollow cone by the optics 17.
  • the central aperture 18 keeps the direct radiation away from the radiation receiver 16.
  • the reference source 12 measures and regulates the radiation emitted by the radiation source 1.
  • the aperture 3 limits the light scattered by smoke on the receiver.
  • the diaphragm 3 engages via a cam 6 in a helical groove 7 located in the cam plate 4. By turning the cam disc 4, the diaphragm 3 moves up or down in the direction of the axis due to the engagement of the cams 6 in the groove 7.
  • the amount of radiation scattered by the smoke onto the radiation receiver 16 is smaller or larger. It has been shown that a shift of the aperture 3 by a few millimeters is sufficient to make the detector less sensitive by a factor of two.
  • an opening 8 is made in the diaphragm 3, which is dimensioned such that an unimpeded radiation passage can take place in each position of the diaphragm 3.
  • this opening can also be used to mechanically change the sensitivity of the smoke detector, as described below.
  • the above-described configuration of the smoke detector according to the invention mechanically changes the solid angle visible by the radiation receiver.
  • the diaphragm 3 instead of the diaphragm 3, it is readily possible to mount a corresponding diaphragm, not shown in the figure, in such a way that the solid angle irradiated by the radiation source 1 is changed mechanically, for example as below the central aperture 18 in the vicinity of the radiation source 1.
  • a possible form for actuating the cam 4 is shown in supervision.
  • the cam disk 4 can be rotated through an elongated hole 5 in the cover 10.
  • the small depression 11 can e.g. be pushed from one stop to another. So that the height of the diaphragm 3 is more precisely defined in both positions, the groove 7 of the cam plate 4 can have a horizontal part instead of a uniformly rising shape at both end stops.
  • the groove 7 also has at least one horizontal section in the central part.
  • the distance between the depressions 11 and the length of the hole 5 are in this case coordinated with one another in such a way that the displacement of a depression 11 from one end of the hole 5 to the other allows the cam 6 to slide straight to the next horizontal section and that the next depression in particular 11 appears at the other end of the hole. If this second recess 11 is moved to the other end of the hole 5, the cam 6 slides exactly to the next horizontal section, etc.
  • a further embodiment of the mechanical adjustment device according to the invention consists of an iris diaphragm or a diaphragm ring, not shown in the figures, i.e. a rotatable disc with openings of different sizes, which are located between the central diaphragm 18 and the radiation source 1 or radiation receiver 16.
  • Another possibility of the mechanical adjustment consists in a variable covering of the reference cell 12.
  • the proportion of the light received by the radiation source 1 becomes smaller.
  • this is controlled for a stronger transmission power, as a result of which the radiation scattered on the smoke, which is received by the radiation receiver 16, becomes larger.
  • This makes the smoke detector more sensitive.
  • This can be done, for example, by changing the opening 8 in the aperture 3.
  • This change can take place by means of inserts into the opening 8 which change the cross section of the opening 8 or by means of a ring which can be rotated about the axis of the smoke detector and which contains openings of different cross sections.
  • the opening 8 can be designed such that a displacement of the diaphragm 3 at the same time causes a change in the cross section of the beam of rays falling through the opening 8 onto the reference cell 12.
  • the signal emitted by the radiation receiver 16 and dependent on the measured smoke density is fed to an evaluation circuit which, when the received signal is exceeded above a predetermined threshold value, forwards a signal to a flip-flop for emitting an alarm signal.
  • This evaluation circuit is not the subject of the present invention.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fire-Detection Mechanisms (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)
  • Vehicle Body Suspensions (AREA)
  • Gyroscopes (AREA)

Abstract

A smoke detector is disclosed containing a radiation source and a radiation receiver arranged externally of a direct radiation region of the radiation source. In the presence of smoke or other combustion particles in the radiation region the radiation receiver is impinged by scattered radiation. The smoke detector contains optical elements which can be altered by external mechanical actuation, by means of which it is possible to alter in a predetermined manner an output signal of the radiation receiver. In this regard it is possible to either mechanically alter the solid angle which is so-to-speak viewed by the radiation receiver or the solid angle irradiated by the radiation source. The constriction of the active solid angle is preferably accomplished by a diaphragm or membrane displaceable along the radiation direction. Displacement of the diagram is preferably achieved in that, this diaphragm engages by means of dogs or detents in a cam groove, such as a helical-shaped groove of a cam disk, and by rotating the cam disk there can be achieved a defined displacement of the diaphragm.

Description

Die Erfindung geht aus von einem nach dem Streustrahlungsprinzip arbeitenden Rauchdetektor der im Oberbegriff des Patentanspruchs 1 definierten Gattung.The invention is based on a smoke detector operating according to the scattered radiation principle of the type defined in the preamble of claim 1.

Ein solcher Rauchdetektor ist beispielsweise aus der US-A-3 992 102 bekannt. Der dort beschriebene Streulicht-Rauchdetektor weist eine zylindrische Rauchkammer auf. Lichtquelle und Empfänger befinden sich annähernd auf der Peripherie des Zylinders und die Empfindlichkeitseinstellung erfolgt mit einer Einstellschraube, die sich in der Mitte des Strahlenganges am oberen Ende einer Platte befindet, die die direkte Bestrahlung des Empfängers durch die Lichtquelle verhindert. Durch das Hineindrehen der Einstellschraube werden nicht nur die Lichtmenge des in den Messraum fallenden Lichts und die Grösse des vom Empfänger einsehbaren Raums verändert, sondern auch (durch Streuung an der Einstellschraube) das bei Nichtvorhandensein von Rauch in den Messraum gestreute Licht. Der Rauchmelder hat zwar den Vorteil, dass die von der Lichtquelle ausgesandte Lichtmenge und die vom Empfänger aufgenommene Lichtmenge mit einer einzigen Einstellvorrichtung eingestellt werden können. Gleichzeitig muss aber in Kauf genommen werden, dass durch eine Erhöhung des Streulichts der Signal-/Rausch-Abstand ungünstig beeinflusst wird. Durch die Anordnung der Einstellschraube in der Mitte des Strahlenganges ist die Einstellung nicht sehr genau.Such a smoke detector is known for example from US-A-3 992 102. The scattered light smoke detector described there has a cylindrical smoke chamber. The light source and receiver are located approximately on the periphery of the cylinder and the sensitivity is adjusted using an adjusting screw located in the middle of the beam path at the top of a plate that prevents the receiver from being directly irradiated by the light source. By turning the adjusting screw in, not only the amount of light falling into the measuring room and the size of the room visible to the receiver are changed, but also (due to the scattering on the adjusting screw) the light scattered into the measuring room in the absence of smoke. The smoke detector has the advantage that the amount of light emitted by the light source and the amount of light received by the receiver can be adjusted with a single setting device. At the same time, however, it must be accepted that the signal-to-noise ratio is adversely affected by an increase in the scattered light. Due to the arrangement of the adjusting screw in the middle of the beam path, the adjustment is not very precise.

Aus der CH-A-592 932 ist ein Rauchmelder bekannt, bei dem die Strahlungsquelle das Licht kegelförmig aussendet, und der Empfänger einen hohlkegelförmigen Raumwinkel einsieht. Der Rauchmelder enthält eine Auswerteschaltung, welche bei Erreichen eines vorbestimmten Signalpegels des empfangenen Streulichts Alarm auslöst. Die Rauchkonzentration, bei welcher Alarm ausgelöst wird, ist fest eingestellt.A smoke detector is known from CH-A-592 932, in which the radiation source emits the light in a conical shape and the receiver sees a hollow-conical solid angle. The smoke detector contains an evaluation circuit which triggers an alarm when a predetermined signal level of the received scattered light is reached. The smoke concentration at which the alarm is triggered is fixed.

Die Empfindlichkeitseinstellung zur Anpassung an unterschiedliche Umgebungsbedingungen kann beispielsweise auch durch Veränderung der Alarmschwelle erreicht werden. Es ist aber häufig vorteilhaft, die einzelnen Melder individuell einstellen zu können. Für lonisationsrauchmelder wurde in der CH-PS 468 683 eine elektrische Schaltungsanordnung zur Empfindlichkeitsveränderung vorgeschlagen, bei welcher die Einstellung der Ansprechschwelle eines als Verstärker und Schwellenwertdetektor dienenden Feldeffekttransistors mittels eines Potentiometers erfolgt, der Teil eines Spannungsteilers ist, mit dem die Source-Elektrode vorgespannt wird. Auch wenn die Einstellung nicht kontinuierlich mit dem Potentiometer vorgenommen wird, sondern mittels eines Schalters, mit dem Festwiderstände unterschiedlicher Grösse in den Stromkreis geschaltet werden, sind solche elektrische Einstellmöglichkeiten störanfällig und nicht korrosionsfest.The sensitivity setting for adaptation to different environmental conditions can also be achieved, for example, by changing the alarm threshold. However, it is often advantageous to be able to set the individual detectors individually. For ionization smoke detectors, an electrical circuit arrangement for changing the sensitivity was proposed in CH-PS 468 683, in which the setting of the response threshold of a field effect transistor serving as an amplifier and threshold value detector takes place by means of a potentiometer, which is part of a voltage divider with which the source electrode is biased. Even if the setting is not made continuously with the potentiometer, but by means of a switch with which fixed resistors of different sizes are switched into the circuit, such electrical setting options are prone to failure and are not corrosion-resistant.

Der Erfindung liegt die Aufgabe zugrunde, einen Rauchdetektor zu schaffen, der die erwähnten Nachteile der bekannten Rauchmelder nicht aufweist und insbesondere einen optischen Rauchdetektor zu schaffen, dessen Empfindlichkeit durch rein mechanische Veränderung optischer Teile definiert verändert werden kann.The invention has for its object to provide a smoke detector which does not have the disadvantages of the known smoke detectors mentioned and in particular to provide an optical smoke detector, the sensitivity of which can be changed in a defined manner by purely mechanical modification of optical parts.

Diese Aufgabe wird erfindungsgemäss durch die im kennzeichnenden Teil des Patentanspruchs 1 definierten Merkmale gelöst. Bevorzugte Ausführungsformen und weitere Ausgestaltungen der Erfindung sind in den abhängigen Ansprüchen definiert.This object is achieved according to the invention by the features defined in the characterizing part of patent claim 1. Preferred embodiments and further refinements of the invention are defined in the dependent claims.

Gemäss einer bevorzugten Ausführungsform des erfindungsgemässen Rauchdetektors erfolgt die Einengung des vom Strahlungsempfänger einsehbaren Raumwinkels durch eine unmittelbar vor dem Strahlungsempfänger angeordnete längs der Strahlungsrichtung verschiebbare Blende.According to a preferred embodiment of the smoke detector according to the invention, the spatial angle visible by the radiation receiver is narrowed by a diaphragm which is arranged directly in front of the radiation receiver and can be displaced along the radiation direction.

Gemäss einer anderen bevorzugten Ausführungsform der Erfindung erfolgt die Einengung des von der Strahlungsquelle auf die Referenzzelle fallenden Lichts durch Veränderung der vor der Referenzzelle in der Blende befindlichen Öffnung.According to another preferred embodiment of the invention, the light falling from the radiation source onto the reference cell is narrowed by changing the opening in the aperture in front of the reference cell.

Die Erfindung wird im folgenden anhand der Zeichnungen beispielshalber erläutert. Es zeigen:

  • Fig. 1 den Aufbau einer Ausführungsform eines Rauchdetektors in Seitenansicht teilweise geschnitten,
  • Fig. 2 die Verstelleinrichtung in Draufsicht und
  • Fig. 3 eine Ausführungsform der Verstelleinrichtung in Seitenansicht.
The invention is explained below by way of example with reference to the drawings. Show it:
  • 1 shows the structure of an embodiment of a smoke detector partially in side view,
  • Fig. 2, the adjustment device in plan view and
  • Fig. 3 shows an embodiment of the adjusting device in side view.

Im Rauchdetektor gemäss Fig. 1 liegt die Strahlungsquelle 1, z.B. ein IR-Strahlung aussendendes Halbleiterelement, im unteren Teil des Melders. Die IR-Strahlung wird durch die Optik 17 hohlkegelförmig gebündelt. Die Zentralblende 18 hält die direkte Strahlung vom Strahlungsempfänger 16 fern. Die Referenzquelle 12 misst und regelt die von der Strahlungsquelle 1 ausgesandte Strahlung. Die Blende 3 begrenzt das durch Rauch auf den Empfänger gestreute Licht. Die Blende 3 greift über einen Nocken 6 in eine in der Kurvenscheibe 4 befindliche, schraubenförmige Nut 7 ein. Durch Drehen der Kurvenscheibe 4 verschiebt sich die Blende 3 durch den Eingriff der Nocken 6 in die Nut 7 in Richtung der Achse auf- oder abwärts. Je nach der Lage der Kurvenscheibe 4 und damit zwangsläufig der Lage der Blende 3, ist die vom Rauch auf den Strahlungsempfänger 16 gestreute Strahlungsmenge kleiner oder grösser. Es hat sich gezeigt, dass eine Verschiebung der Blende 3 um einige Millimeter nach unten genügt, um den Melder um einen Faktor zwei unempfindlicher zu machen.The radiation source 1, e.g. a semiconductor element emitting IR radiation, in the lower part of the detector. The IR radiation is bundled in a hollow cone by the optics 17. The central aperture 18 keeps the direct radiation away from the radiation receiver 16. The reference source 12 measures and regulates the radiation emitted by the radiation source 1. The aperture 3 limits the light scattered by smoke on the receiver. The diaphragm 3 engages via a cam 6 in a helical groove 7 located in the cam plate 4. By turning the cam disc 4, the diaphragm 3 moves up or down in the direction of the axis due to the engagement of the cams 6 in the groove 7. Depending on the position of the cam plate 4 and thus inevitably the position of the diaphragm 3, the amount of radiation scattered by the smoke onto the radiation receiver 16 is smaller or larger. It has been shown that a shift of the aperture 3 by a few millimeters is sufficient to make the detector less sensitive by a factor of two.

Wichtig ist dabei, dass die Blende 3 bei ihrer Bewegung den Strahlengang von der Strahlungsquelle 1 zur Referenzzelle 16 nicht stört. Daher ist in der Blende 3 eine Öffnung 8 angebracht, die so bemessen ist, dass bei jeder Stellung der Blende 3 ein ungehinderter Strahlungsdurchtritt erfolgen kann. Diese Öffnung kann jedoch auch zur mechanischen Empfindlichkeitsveränderung des Rauchdetektors benutzt werden, wie weiter unten beschrieben wird.It is important that the aperture 3 does not disturb the beam path from the radiation source 1 to the reference cell 16 during its movement. Therefore, an opening 8 is made in the diaphragm 3, which is dimensioned such that an unimpeded radiation passage can take place in each position of the diaphragm 3. However, this opening can also be used to mechanically change the sensitivity of the smoke detector, as described below.

Durch die vorstehend beschriebene Ausgestaltung des erfindungsgemässen Rauchdetektors wird der vom Strahlungsempfänger einsehbare Raumwinkel mechanisch verändert. Es ist jedoch ohne weiteres möglich, anstelle der Blende 3 eine entsprechende, in der Figur nicht dargestellte Blende so anzubringen, dass der von der Strahlungsquelle 1 bestrahlte Raumwinkel mechanisch verändert wird, beispielsweise unterhalb der Zentralblende 18 in der Nähe der Strahlungsquelle 1.The above-described configuration of the smoke detector according to the invention mechanically changes the solid angle visible by the radiation receiver. However, instead of the diaphragm 3, it is readily possible to mount a corresponding diaphragm, not shown in the figure, in such a way that the solid angle irradiated by the radiation source 1 is changed mechanically, for example as below the central aperture 18 in the vicinity of the radiation source 1.

In Fig. 2 ist in Aufsicht eine mögliche Form zur Betätigung der Kurvenscheibe 4 dargestellt. Durch ein längliches Loch 5 in der Abdeckung 10 lässt sich die Kurvenscheibe 4 drehen. Dabei kann die kleine Vertiefung 11 z.B. von einem Anschlag zum anderen geschoben werden. Damit die Höhe der Blende 3 in beiden Stellungen noch genauer definiert wird, kann die Nut 7 der Kurvenscheibe 4 statt einer gleichmässig steigenden Form an beiden Endanschlägen je einen waagrechten Teil besitzen.In Fig. 2 a possible form for actuating the cam 4 is shown in supervision. The cam disk 4 can be rotated through an elongated hole 5 in the cover 10. The small depression 11 can e.g. be pushed from one stop to another. So that the height of the diaphragm 3 is more precisely defined in both positions, the groove 7 of the cam plate 4 can have a horizontal part instead of a uniformly rising shape at both end stops.

In Fig. 3 ist eine bevorzugte Ausführungsform der Kurvenscheibe 4 dargestellt. Dabei weist die Nut 7 ausser an den Enden auch im mittleren Teil mindestens ein horizontales Teilstück auf. In diesem Fall ist auch mehr als eine kleine Vertiefung 11 vorhanden. Der Abstand der Vertiefungen 11 und die Länge des Lochs 5 sind in diesem Fall so aufeinander abgestimmt, dass die Verschiebung einer Vertiefung 11 von einem Ende des Lochs 5 zum anderen den Nokken 6 gerade bis zum nächsten horizontalen Teilstück gleiten lässt und dass gerade die nächste Vertiefung 11 am anderen Ende des Lochs erscheint. Wird diese zweite Vertiefung 11 zum anderen Ende des Lochs 5 verschoben, so gleitet der Nocken 6 genau bis zum nächsten horizontalen Teilstück, usw.3 shows a preferred embodiment of the cam disk 4. In addition to the ends, the groove 7 also has at least one horizontal section in the central part. In this case there is also more than one small depression 11. The distance between the depressions 11 and the length of the hole 5 are in this case coordinated with one another in such a way that the displacement of a depression 11 from one end of the hole 5 to the other allows the cam 6 to slide straight to the next horizontal section and that the next depression in particular 11 appears at the other end of the hole. If this second recess 11 is moved to the other end of the hole 5, the cam 6 slides exactly to the next horizontal section, etc.

Eine weitere Ausführungsform der erfindungsgemässen mechanischen Verstellvorrichtung besteht in einer - in den Figuren nicht dargestellten - Irisblende oder einem Blendenring, d.h. einer drehbaren Scheibe mit unterschiedlich grossen Öffnungen, die sich zwischen Zentralblende 18 und Strahlungsquelle 1 oder Strahlungsempfänger 16 befinden.A further embodiment of the mechanical adjustment device according to the invention consists of an iris diaphragm or a diaphragm ring, not shown in the figures, i.e. a rotatable disc with openings of different sizes, which are located between the central diaphragm 18 and the radiation source 1 or radiation receiver 16.

Eine andere Möglichkeit der mechanischen Verstellung besteht in einer variablen Abdeckung der Referenzzelle 12. Durch Abdecken der Referenzzelle 12 wird der Anteil des empfangenen Lichts von der Strahlungsquelle 1 kleiner. Dadurch wird diese auf eine stärkere Sendeleistung gesteuert, wodurch die am Rauch gestreute Strahlung, die vom Strahlungsempfänger 16 aufgenommen wird, grösser wird. Der Rauchdetektor wird dadurch empfindlicher. Dies kann beispielsweise durch eine Veränderung der Öffnung 8 in der Blende 3 erfolgen. Diese Veränderung kann durch Einsätze in die Öffnung 8 erfolgen, welche den Querschnitt der Öffnung 8 verändern oder durch einen um die Achse des Rauchdetektors drehbaren Ring, der Öffnungen verschiedener Querschnitte enthält. Schliesslich kann die Öffnung 8 so gestaltet sein, dass eine Verschiebung der Blende 3 gleichzeitig eine Veränderung des Querschnittes des durch die Öffnung 8 auf die Referenzzelle 12 fallenden Strahlenbündels bewirkt.Another possibility of the mechanical adjustment consists in a variable covering of the reference cell 12. By covering the reference cell 12, the proportion of the light received by the radiation source 1 becomes smaller. As a result, this is controlled for a stronger transmission power, as a result of which the radiation scattered on the smoke, which is received by the radiation receiver 16, becomes larger. This makes the smoke detector more sensitive. This can be done, for example, by changing the opening 8 in the aperture 3. This change can take place by means of inserts into the opening 8 which change the cross section of the opening 8 or by means of a ring which can be rotated about the axis of the smoke detector and which contains openings of different cross sections. Finally, the opening 8 can be designed such that a displacement of the diaphragm 3 at the same time causes a change in the cross section of the beam of rays falling through the opening 8 onto the reference cell 12.

Das von dem Strahlungsempfänger 16 abgegebene, von der gemessenen Rauchdichte abhängige Signal wird einer Auswerteschaltung zugeführt, welche bei Überschreiten des Empfangssignals über einen vorgegebenen Schwellwert ein Signal an eine Kippstufe zur Abgabe eines Alarmsignals weiterleitet. Diese Auswerteschaltung ist nicht Gegenstand der vorliegenden Erfindung.The signal emitted by the radiation receiver 16 and dependent on the measured smoke density is fed to an evaluation circuit which, when the received signal is exceeded above a predetermined threshold value, forwards a signal to a flip-flop for emitting an alarm signal. This evaluation circuit is not the subject of the present invention.

Claims (8)

1. A smoke detector comprising a radiation source (1), A radiation receiver (16) arranged externally of the direct radiation region of the radiation source (1), said radiation receiver (16) being impinged by radiation scattered by smoke particles located in the direct radiation region and delivering an output signal, said output signal of the radiation receiver (16) being altered in a predetermined manner by externally actuable mechanically altering of elements (3, 8) characterized in that said radiation source (1) is structured to transmit a substantially hollow conical-shaped beam of radiation, that said radiation receiver (16) is structured such that it views a substantially hollow conical-shaped solid angle along the cone axis, and that the alteration of the output signal of said radiation receiver (16) is effected by optical means (3, 8) concentrically constricting the solid angle irradiated by the radiation source (1), the solid angle which is viewed by the radiation receiver (16) or the light impinging from the radiation source (1) directly on a reference cell (12) controlling the amount of radiation emitted from the radiation source (1).
2. Smoke detector according to claim 1, characterized in that the constriction of said solid angle which is viewed by the radiation receiver (16) is effected by a diaphragm (3) displaceable along the direction of radiation.
3. Smoke detector according to claim 2, characterized in that the diaphragm (3) displaceable along the direction of radiation engages with cams (6) into a substantially helical groove (7) being on a cam disk (4), and that upon rotation of said cam disk (4) a defined displacement of said diaphragm (3) is accomplished.
4. Smoke detector according to claim 3, characterized in that said groove (7) of said cam disk (4) contains at least two substantially horizontally extending portions effectuating a defined adjustment of the diaphragm (3).
5. Smoke detector according to any of claims 4 and 5, characterized in that the cam disk (4) is possible to be actuated through at least one elongate hole (5) in the cover.
6. Smoke detector according to claim 2, characterized in that the constriction of said solid angle which is viewed by the radiation receiver (16) is effectuated by an iris diaphragm.
7. Smoke detector according to any of claims 1 to 6, characterized in that the constriction of the light impinging from the radiation source (1) on the reference cell (12) is effectuated by altering the opening (8) which is in said diaphragm (3) before said reference cell (12).
8. Smoke detector according to any of claims 1 to 7, characterized in that an evaluation circuit is provided, which when a received signal exceeds a predetermined threshold value delivers a signal to a tilt stage for outputting an alarm signal.
EP82110014A 1981-11-11 1982-10-29 Smoke detector Expired EP0079011B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82110014T ATE17061T1 (en) 1981-11-11 1982-10-29 SMOKE DETECTOR.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH7250/81A CH656474A5 (en) 1981-11-11 1981-11-11 SMOKE DETECTOR.
CH7250/81 1981-11-11

Publications (2)

Publication Number Publication Date
EP0079011A1 EP0079011A1 (en) 1983-05-18
EP0079011B1 true EP0079011B1 (en) 1985-12-18

Family

ID=4322193

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82110014A Expired EP0079011B1 (en) 1981-11-11 1982-10-29 Smoke detector

Country Status (17)

Country Link
US (1) US4524281A (en)
EP (1) EP0079011B1 (en)
JP (1) JPS5888643A (en)
AT (1) ATE17061T1 (en)
AU (1) AU556837B2 (en)
BR (1) BR8206535A (en)
CA (1) CA1208333A (en)
CH (1) CH656474A5 (en)
DE (1) DE3268057D1 (en)
DK (1) DK502482A (en)
ES (1) ES8309022A1 (en)
FI (1) FI75438C (en)
IL (1) IL67159A0 (en)
NO (1) NO157156C (en)
NZ (1) NZ202364A (en)
YU (1) YU252282A (en)
ZA (1) ZA828096B (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS626144A (en) * 1985-07-03 1987-01-13 Nittan Co Ltd Photoelectric type smoke sensor
US4814748A (en) * 1987-11-09 1989-03-21 Southwest Laboratories, Inc. Temporary desensitization technique for smoke alarms
GB2259763B (en) * 1991-09-20 1995-05-31 Hochiki Co Fire alarm system
ITTO20070355A1 (en) * 2007-05-18 2008-11-19 Elkron Spa DEVICE AND METHOD TO DETECT SMOKE
GB2537940B (en) 2015-05-01 2018-02-14 Thorn Security Fire detector drift compensation

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB966867A (en) * 1961-01-05 1964-08-19 Pyrene Co Ltd Improvements relating to smoke indicators
GB1172354A (en) * 1966-02-16 1969-11-26 Pyrene Co Ltd Improvements relating to Smoke Detectors
JPS4418923Y1 (en) * 1966-09-16 1969-08-14
US3868184A (en) * 1973-07-25 1975-02-25 Electro Signal Lab Optical smoke detector with light scattering test device
JPS50134172A (en) * 1974-04-17 1975-10-24
US3985453A (en) * 1974-07-19 1976-10-12 Matsushita Electric Works, Ltd. Light scattering type smoke detector
US4011458A (en) * 1975-10-09 1977-03-08 Pyrotector, Incorporated Photoelectric detector with light source intensity regulation
FR2357888A1 (en) * 1976-04-01 1978-02-03 Cerberus Ag SMOKE DETECTOR
US4216377A (en) * 1977-06-27 1980-08-05 Nittan Company, Limited Light scattering smoke detector
US4269510A (en) * 1978-12-21 1981-05-26 Cerberus Ag Smoke detector
US4430646A (en) * 1980-12-31 1984-02-07 American District Telegraph Company Forward scatter smoke detector

Also Published As

Publication number Publication date
AU556837B2 (en) 1986-11-20
FI75438C (en) 1988-06-09
NO157156B (en) 1987-10-19
EP0079011A1 (en) 1983-05-18
YU252282A (en) 1985-10-31
DE3268057D1 (en) 1986-01-30
NO157156C (en) 1988-01-27
JPS5888643A (en) 1983-05-26
ZA828096B (en) 1983-09-28
BR8206535A (en) 1983-09-27
FI75438B (en) 1988-02-29
NO823754L (en) 1983-05-13
FI823838L (en) 1983-05-12
CA1208333A (en) 1986-07-22
FI823838A0 (en) 1982-11-09
ATE17061T1 (en) 1986-01-15
ES517588A0 (en) 1983-10-01
ES8309022A1 (en) 1983-10-01
US4524281A (en) 1985-06-18
IL67159A0 (en) 1983-03-31
NZ202364A (en) 1986-04-11
CH656474A5 (en) 1986-06-30
DK502482A (en) 1983-05-12
AU9017582A (en) 1983-05-19

Similar Documents

Publication Publication Date Title
DE4328671B4 (en) Scattered light smoke
DE2828190A1 (en) Scattered light smoke sensor
DE2749494A1 (en) OPTICAL SMOKE DETECTOR
DE69323064T2 (en) Spatially resolved analysis of a sample using an X-ray fluorescence spectrometer
DE2924685A1 (en) REFLECTIVE TYPE PHOTOELECTRIC SWITCHING DEVICE
DE4034602A1 (en) ARRANGEMENT FOR MEASURING THE IMPULSE TRANSMISSION SPECTRUM OF ROENTGEN QUANTS
DE2310817C3 (en) Device for detecting particles carried along in a fluid, in particular smoke alarms
DE3925148A1 (en) PARTICLE COUNTER
DE4028188A1 (en) FIRE DETECTORS WITH A SPARKLIGHT AND IONIZATION SYSTEM
EP0821330B1 (en) Smoke detector
EP0079011B1 (en) Smoke detector
DE2515367C3 (en) Photoelectric smoke detector
DE3307639C2 (en) Optical potentiometer
DE2744831C2 (en) Ionization chamber for an ionization smoke detector
DE2709866A1 (en) Detector for suspended particles - has radiation receivers for direct and scattered radiation and evaluation circuit
EP0105199A1 (en) Radiation smoke alarm
DE3525264A1 (en) DROP DETECTOR
CH422370A (en) Photoelectric measuring device
DE19540299A1 (en) Infrared movement warning device with two switchable detectors
CH430264A (en) Photoelectric light meter
DE2742274C2 (en) Ionization chamber for an ionization smoke detector
DE2908100C2 (en) Smoke detector
DE68928714T2 (en) Rotary drive device of a variable resistor
DE2514931B2 (en) Television pick-up tube with an auxiliary lighting arrangement
EP0821331A1 (en) Smoke detector

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19821029

AK Designated contracting states

Designated state(s): AT BE DE FR GB IT LU NL SE

ITF It: translation for a ep patent filed
GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): AT BE DE FR GB IT LU NL SE

REF Corresponds to:

Ref document number: 17061

Country of ref document: AT

Date of ref document: 19860115

Kind code of ref document: T

REF Corresponds to:

Ref document number: 3268057

Country of ref document: DE

Date of ref document: 19860130

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19861031

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 19890911

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19890912

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 19890915

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 19890927

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: LU

Payment date: 19890928

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19890930

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19891002

Year of fee payment: 8

ITTA It: last paid annual fee
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19891031

Year of fee payment: 8

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19901029

Ref country code: AT

Effective date: 19901029

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19901030

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Effective date: 19901031

BERE Be: lapsed

Owner name: CERBERUS A.G.

Effective date: 19901031

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19910501

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
GBPC Gb: european patent ceased through non-payment of renewal fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19910628

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19910702

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

EUG Se: european patent has lapsed

Ref document number: 82110014.6

Effective date: 19910603