EP0821330B1 - Smoke detector - Google Patents

Smoke detector Download PDF

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Publication number
EP0821330B1
EP0821330B1 EP96111751A EP96111751A EP0821330B1 EP 0821330 B1 EP0821330 B1 EP 0821330B1 EP 96111751 A EP96111751 A EP 96111751A EP 96111751 A EP96111751 A EP 96111751A EP 0821330 B1 EP0821330 B1 EP 0821330B1
Authority
EP
European Patent Office
Prior art keywords
light
base
measuring chamber
smoke 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 - Lifetime
Application number
EP96111751A
Other languages
German (de)
French (fr)
Other versions
EP0821330A1 (en
Inventor
Urs Riedi
Bernhard Durrer
Kurt Dr. Hess
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.)
Siemens Building Technologies AG
Original Assignee
Siemens Building Technologies 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.)
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Publication date
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Application filed by Siemens Building Technologies AG filed Critical Siemens Building Technologies AG
Priority to ES96111751T priority Critical patent/ES2183899T3/en
Priority to DE59609625T priority patent/DE59609625D1/en
Priority to EP96111751A priority patent/EP0821330B1/en
Priority to AT96111751T priority patent/ATE223604T1/en
Priority to ZA9705811A priority patent/ZA975811B/en
Priority to UA98031427A priority patent/UA42086C2/en
Priority to PL97325921A priority patent/PL184244B1/en
Priority to AU33327/97A priority patent/AU725418B2/en
Priority to KR10-1998-0701678A priority patent/KR100467130B1/en
Priority to CNB971909334A priority patent/CN1135511C/en
Priority to RU98107584/09A priority patent/RU2189080C2/en
Priority to PCT/CH1997/000269 priority patent/WO1998003946A1/en
Publication of EP0821330A1 publication Critical patent/EP0821330A1/en
Publication of EP0821330B1 publication Critical patent/EP0821330B1/en
Application granted granted Critical
Anticipated expiration legal-status Critical
Expired - Lifetime 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 smoke detector with a detector insert which can be fastened in a base and has an optical module which has a light source, a light receiver, a measuring chamber, a floor covering the measuring chamber and a labyrinth system with diaphragms arranged on the periphery of the measuring chamber.
  • smoke detectors of this type which are referred to as scattered-light smoke detectors, and which may optionally contain a further sensor, for example a temperature sensor
  • the optical module is designed in such a way that disturbing extraneous light cannot penetrate and smoke can very easily penetrate the measuring chamber.
  • the light source and light receiver are arranged in such a way that no light rays can get directly from the source to the receiver.
  • the light from the light source In the presence of smoke particles in the beam path, the light from the light source is scattered thereon and part of this scattered light falls on the light receiver and causes an electrical signal. It is obvious that the false alarm security of such scattered-light smoke detectors depends, among other things, on the fact that the light from the light source is only scattered on smoke particles, that is, with the exception of the smoke particles, no other particles can get into the measuring chamber, with the expression particles being the broadest Meaning is to be understood and includes insects, for example. The problem with the insects has been recognized for some time and is solved by an insect screen surrounding the measuring chamber.
  • a scattered light smoke detector known from DE-A-44 12 212 contains a measuring chamber in the form of a round box, which is attached with an end face to a plate connected to the ceiling of the room to be monitored and the side wall of which is formed by an insect screen.
  • the end of the measuring chamber facing away from the plate mentioned and facing the tip is covered by a flat bottom.
  • the base is funnel-shaped and has the shape of a cone or a pyramid.
  • the solution according to the invention brings about a drastic reduction in the interference of dust particles, because they are now much further away from the actual measuring zone than hitherto, as a result of which the probability that light scattered from dust particles reaches the measuring zone has become significantly lower.
  • the optical axes of the light source and light receiver intersect in the area of the center of the measuring chamber and thus also the center of the floor.
  • the base has a sieve or lattice structure and acts as an insect screen. This embodiment has the advantage that the smoke detector has one component less than before, which is associated with a corresponding cost advantage.
  • a second preferred embodiment of the smoke detector according to the invention is characterized in that the bottom of its inner surface facing the measuring chamber is provided with a plurality of lamellae projecting vertically upwards, and in that the arrangement, number, height and mutual spacing of these lamellae are selected such that against light falling on the floor hits one of the slats before it hits it, and the light receiver only sees the slats from the floor.
  • the inventive design of the floor with the slats directed upward further reduces the probability that light from the beam path in the measuring chamber is scattered on dust particles deposited on the floor.
  • the dust particles will not be deposited on the lamellae, but rather on their base on the inner surface of the floor, and this is an area that is lamellarized from light from the measuring chamber.
  • the slats also act as a shield against external light from the outside, which further increases the measuring reliability of the smoke detector according to the invention.
  • the scattered-light smoke detector shown consists in a known manner of a detector insert 1, which can be fastened in a base (not shown) which is preferably mounted on the ceiling of the room to be monitored, and a detector hood 2 which is placed over the detector insert 1 and which is in the area of its in the operating state of the Detector against the space to be monitored is provided with smoke inlet slots 3.
  • the detector insert 1 essentially comprises a box-like base body, on the side facing the top of the detector an optical module 5 surrounded by a side wall 4 and on the side facing the detector base a printed circuit board with evaluation electronics (not shown) are arranged.
  • This detector structure is known and will not be described in more detail here. In this context, reference is made, for example, to the detectors of the AlgoRex series ( AlgoRex - registered trademark of Cerberus AG) and to European patent application No. 95117405.1.
  • the optics module 5 essentially consists of a light source 6, a light receiver 7, a measuring chamber 8, a labyrinth system on the inside of the side wall 4 arranged peripheral panels 9, a central panel 10 and a bottom 11.
  • the optical axes of the light source formed by an infrared light emitting diode (IRED) 6 and the light receiver 7 are not on a common straight line, but are kinked, with the central one near the intersection Aperture 10 is arranged.
  • the side wall 4 and the bottom 11 shield the measuring chamber 8 against external light from the outside, and the peripheral panels 9 and the central Aperture 10 prevent light rays in a direct path from the light source 6 to Light receiver 7 can get.
  • the peripheral diaphragms 9 are also used for suppression the so-called underground light, which is caused by undesirable scattering or reflections.
  • the intersection of that emitted by the light source 6 Beams and the field of view of the light receiver 7 form the following the actual measuring range referred to as the scattering space.
  • the light source 6 sends short, intense light pulses into the scattering space, the light receiver 7 indeed "sees” the scattering space, but not the light source 6.
  • the light of the Light source 6 is scattered by smoke entering the scattering space, and a part this scattered light falls on the light receiver 7.
  • the receiver signal generated thereby is processed by the electronics.
  • the smoke detector can be next to the optical sensor system contained in the optical module 5, further sensors, for example contain a temperature and / or a gas sensor.
  • the bottom 11 has a sieve or lattice-like structure and is on the outside with star-shaped ribs 12 provided, through which the smoke is brought to the floor. This flows the smoke in the vertical direction into the measuring chamber 8 and into the spreading space.
  • the base 11 has one from the measuring chamber much larger distance than is the case with a flat floor.
  • the Measuring chamber 8 penetrated dust particles that scatter the light from the light source 5 and therefore act like smoke particles, are deposited in the top of the bottom 11 and are are there outside the area of incidence of the radiation from the light source 6, whereby the interference of these smoke particles is drastically reduced.
  • the funnel-shaped area of the base 11 has the Form a pyramid or a truncated pyramid, with all side surfaces the pyramid have the sieve-like or lattice-like structure already mentioned. 1 is off For the sake of clearer recognition, only one of the pyramid surfaces lattice-like structure 13 schematically indicated.
  • the ribs 12 on the outside of the Bottom 11 are preferably arranged along the pyramid side edges.
  • the probability of interference from dust particles deposited on the floor 11 is further reduced by special training of the soil.
  • This increases the risk of scattering of light on dust particles much less, since the dust is much closer to the floor remains to adhere to the vertical walls of the slats.
  • additionally to shield the floor 11 against light from the measuring chamber 8 shield the slats 14, 15 the light receiver 7 against external light from the outside.
  • not all pyramid surfaces are provided with lamellas, but only that of the light source 6 and that opposite the light receiver 7 and that between pyramid surface enclosed between these two surfaces. That of the light source 6 and the light receiver 7 opposite pyramid surfaces are parallel to Base edge of the pyramid oriented longitudinal slats 14 and those between these surfaces enclosed pyramid surface is with at least one longitudinal lamella 14 and provided with several transverse lamellae 15 oriented perpendicular to this.
  • the longitudinal slats 14 run at least approximately perpendicular to the optical axis of the opposite one Light source or the opposite light receiver.
  • the cross slats 15 serve primarily for the optical decoupling of light source 6 and light receiver 7th
  • the optics module 5 For even better absorption of background light, at least certain parts have of the optics module 5, in particular the peripheral diaphragms 9, the central diaphragm 10 and the the floor of the measuring chamber 8 opposite the floor 11, instead of the previously usual matt surfaces shiny, i.e. reflective, surfaces on. Of course can still other parts or the entire inside of the optics module 5 a shiny Have surface.
  • peripheral panels 9 or at least most of them are not rotationally symmetrical but are arranged so that the Impact angle of that emitted by the light source 6 and that of the light receiver 7 received light beam on these diaphragms is constant.
  • Peripheral diaphragms 9 would be those that rotate by rotating an aperture around the center are formed.
  • those of the light source 6 and the light receiver 7 are adjacent Four peripheral diaphragms 9 each are not rotationally symmetrical.
  • the angle of incidence is chosen so that the incident and not absorbed light as often as possible is reflected between the peripheral diaphragms 9.
  • the peripheral panels 9 each consist of two angled partial surfaces, their mutual inclination and the distance and the length of the peripheral diaphragms 9 are selected so that the light emitted to the peripheral diaphragms 9 can not get directly onto the inner surface of the side wall 4, but in any case meets a peripheral panel 9 and from this to the adjacent peripheral panel is reflected.
  • the non-rotationally symmetrical arrangement of the majority of the peripheral diaphragms 9 leads to better absorption of the background light and thus less stringent requirements for the positioning and component accuracy of the light source 6 and light receiver 7 and a less pollution-prone detector.
  • the peripheral covers 9 are against their Central aperture 10 directed inner edge formed as sharp as possible. That has the The advantage that only a little light falls on such a sharp edge and therefore less light is reflected in a variety of directions.
  • the sharpness is an edge a limit is set by the thickness of the wire used, which meets the requirements to the inner edges of the peripheral panels 9 is not sufficient.
  • detector 1 the desired sharpness of the inner edges is achieved by using the injection mold a core is used, which is provided on its for forming the inner edges Periphery has a stepped (serrated or serrated) contour. The single ones Gradations of this contour lie on the inside to form the peripheral diaphragms 9 grooves formed in the injection mold and close them against the center from. This allows between the grooves of the injection mold and the gradations very sharp edges are formed of the core.
  • peripheral shutters 9 with sharp inner edges and optical module parts (peripheral covers 9, Central aperture 10, ceiling of the measuring chamber 8) with a shiny surface to a striking Reduction of the basic pulse leads and that the detector is less dusty and becomes susceptible to condensation.
  • the light source 6 and the light receiver 7 each arranged in a housing 16 or 17.
  • the two housings 16 and 17, which are worked on the ceiling of the measuring chamber 8, are open at the bottom and are covered on their open side by the floor 11.
  • the housing 16 and 17 At her the central aperture 10 facing front are the housing 16 and 17 each through a window with a Light exit or light entry opening completed. These windows face the Housing windows of known scattered-light smoke detectors make the difference that they are in one piece are trained.
  • the windows consist of two parts, from one worked on the ceiling of the measuring chamber and the other on the floor is.
  • the floor When fitting the floor, there are always problems with fitting and it comes to the formation of a light gap between the two halves of the window and thus unwanted interference in the transmitted and received light.
  • windows Disruptions of this kind are excluded and no problems can arise occur with the positioning accuracy of the two window halves.
  • the top and bottom are Half of the one-piece windows in the manner of the two cutting edges of scissors against each other added.
  • the injection molding tool can be designed without side pull, that for each of the two mutually offset halves of the light output and the Light entry opening a separate shaped element is provided, so that a precisely defined Shape and a clean surface of these openings is achieved.

Abstract

The smoke detector has a fixing socket in which a detector insert with an optical module is fitted. The optical module has a light source (6) and a photodetector (7) contained within a measuring chamber having a base (11). The module further has a labyrinth system provided by plates (9) projecting inwards from the periphery of the measuring chamber. The base of the measuring chamber has a conical or pyramid shape so that its centre lies at a greater distance from the plane containing the light source and the photodetector than its periphery.

Description

Die Erfindung betrifft einen Rauchmelder mit einem in einem Sockel befestigbaren Meldereinsatz mit einem Optikmodul, welches eine Lichtquelle, einen Lichtempfänger, eine Messkammer, einen die Messkammer abdeckenden Boden und ein Labyrinthsystem mit an der Peripherie der Messkammer angeordneten Blenden aufweist.
Bei Rauchmeldern dieser Art, die als Streulichtrauchmelder bezeichnet werden, und die gegebenenfalls neben dem Optikmodul noch einen weiteren Sensor, beispielsweise einen Temperatursensor, enthalten können, ist bekanntlich das Optikmodul so ausgebildet, dass störendes Fremdlicht nicht und Rauch sehr leicht in die Messkammer eindringen kann. Lichtquelle und Lichtempfänger sind so angeordnet, dass keine Lichtstrahlen auf direktem Weg von der Quelle zum Empfänger gelangen können. Bei Anwesenheit von Rauchpartikeln im Strahlengang wird das Licht der Lichtquelle an diesen gestreut und ein Teil dieses gestreuten Lichts fällt auf den Lichtempfänger und bewirkt ein elektrisches Signal.
Es liegt auf der Hand, dass die Fehlalarmsicherheit solcher Streulichtrauchmelder unter anderem ganz wesentlich davon abhängt, dass das Licht der Lichtquelle nur an Rauchpartikeln gestreut wird, dass also mit Ausnahme der Rauchpartikel keine anderen Partikel in die Messkammer gelangen können, wobei der Ausdruck Partikel im weitesten Sinn zu verstehen ist und beispielsweise Insekten einschliesst. Das Problem mit den Insekten ist seit einiger Zeit erkannt und wird durch ein die Messkammer umgebendes Insektengitter gelöst.
Ein aus der DE-A-44 12 212 bekannter Streulichtrauchmelder enthält eine Messkammer von der Form einer runden Schachtel, die mit einer Stirnseite an einer mit der Decke des zu überwachenden Raumes verbundenen Platte befestigt und deren Seitenwand durch ein Insektengitter gebildet ist. Die von der genannten Platte abgewandte und der Melderkuppe zugekehrte Stimseite der Messkammer ist durch einen flachen Boden abgedeckt. The invention relates to a smoke detector with a detector insert which can be fastened in a base and has an optical module which has a light source, a light receiver, a measuring chamber, a floor covering the measuring chamber and a labyrinth system with diaphragms arranged on the periphery of the measuring chamber.
In smoke detectors of this type, which are referred to as scattered-light smoke detectors, and which may optionally contain a further sensor, for example a temperature sensor, in addition to the optical module, it is known that the optical module is designed in such a way that disturbing extraneous light cannot penetrate and smoke can very easily penetrate the measuring chamber. The light source and light receiver are arranged in such a way that no light rays can get directly from the source to the receiver. In the presence of smoke particles in the beam path, the light from the light source is scattered thereon and part of this scattered light falls on the light receiver and causes an electrical signal.
It is obvious that the false alarm security of such scattered-light smoke detectors depends, among other things, on the fact that the light from the light source is only scattered on smoke particles, that is, with the exception of the smoke particles, no other particles can get into the measuring chamber, with the expression particles being the broadest Meaning is to be understood and includes insects, for example. The problem with the insects has been recognized for some time and is solved by an insect screen surrounding the measuring chamber.
A scattered light smoke detector known from DE-A-44 12 212 contains a measuring chamber in the form of a round box, which is attached with an end face to a plate connected to the ceiling of the room to be monitored and the side wall of which is formed by an insect screen. The end of the measuring chamber facing away from the plate mentioned and facing the tip is covered by a flat bottom.

Der praktische Einsatz derartiger Streulichtrauchmelder mit einer flachen zylindlischen Messkammer hat gezeigt, dass bei diesen mit zunehmender Einsatzdauer die Fehlalarmhäufigkeit zunehmen kann, wobei eine wesentliche Ursache dafür darin zu suchen ist, dass das Licht der Lichtquelle an in der Messkammer abgelagerten Staubpartikeln gestreut und dadurch das Vorhandensein von Rauchpartikeln vorgetäuscht wird. Um das Auftreten solcher Fehlalarme auszuschliessen, müssen die Melder von Zeit zu Zeit von Staub gereinigt werden, was einen unerwünschten zusätzlichen Aufwand darstellt.
Durch die Erfindung soll nun ein Rauchmelder der eingangs genannten Art angegeben werden, bei dem die Auslösung von Fehlalarmen wegen Lichtstreuung an Staubpartikeln möglichst vollständig vermieden oder jedenfalls stark verringert und dadurch eine Verlängerung der Wartungsintervalle erreicht wird.
Die gestellte Aufgabe wird erfindungsgemäss dadurch gelöst, dass der Boden trichterförmig ausgebildet ist und die Form eines Kegels oder einer Pyramide aufweist.
Die erfindungsgemässe Lösung bewirkt eine drastische Verringerung des Störeinflusses von Staubpartikeln, weil diese jetzt wesentlich weiter von der eigentlichen Messzone entfernt sind als bisher, wodurch die Wahrscheinlichkeit, dass an Staubpartikeln gestreutes Licht in die Messzone gelangt, wesentlich geringer geworden ist.
Bekanntlich schneiden die optischen Achsen von Lichtquelle und Lichtempfänger einander im Bereich des Zentrums der Messkammer und damit auch der Mitte des Bodens. Da der Boden gerade hier im Bereich seiner Kuppe oder Spitze seinen grössten Abstand von der Messebene aufweist, und da sich Staub vorwiegend in diesem Bodenbereich ablagern wird, ist es sehr unwahrscheinlich, dass von der Lichtquelle ausgesandtes Licht zu einem an der Kuppe des Bodens abgelagerten Staubpartikel gelangt und von diesem in die Messkammer zurückgestreut wird.
Aus der DE-A-33 34 545 ist ein Rauchmelder mit einem kegelstumpfförmigen Boden und zwei Lichtquellen bekannt, der im Boden zwei relativ grosse Öffnungen aufweist, durch welche die Sendestrahlen der beiden Lichtquellen reflexionsfrei nach aussen verschwinden. Dieser Melder weist kein Labyrinth auf, weil ein solches wegen der genannten Öffnungen nicht erforderlich ist, und er ist ausserdem von länglicher zylindrischer Form, wobei die Höhe der Messkammer grösser ist als deren Durchmesser. Daher stellt sich bei diesem Melder das Problem der Lichtstreuung durch am Boden der Messkammer abgelagerte Staubpartikel nicht.
Bei einer ersten bevorzugten Ausführungsform des erfindungsgemässen Rauchmelders weist der Boden eine sieb- oder gitterförmige Struktur auf und wirkt als Insektengitter. Diese Ausführungsform hat den Vorteil, dass der Rauchmelder ein Bauteil weniger als bisher aufweist, was mit einem entsprechenden Kostenvorteil verbunden ist.
Eine zweite bevorzugte Ausführungsform des erfindungsgemässen Rauchmelders ist dadurch gekennzeichnet, dass der Boden an seiner der Messkammer zugekehrten Innenfläche mit einer Mehrzahl von vertikal nach oben ragenden Lamellen versehen ist, und dass Anordnung, Anzahl, Höhe und gegenseitiger Abstand dieser Lamellenen so gewählt sind, dass gegen den Boden fallendes Licht vor dem Auftreffen auf diesen auf eine der Lamellen trifft, und dass der Lichtempfänger vom Boden nur die Lamellen sieht.
Die erfindungsgemässe Ausbildung des Bodens mit den nach oben gerichteten Lamellen reduziert nochmals die Wahrscheinlichkeit, dass Licht aus dem Strahlengang in der Messkammer an auf dem Boden abgelagerten Staubpartikeln gestreut wird. Denn die Staubpartikel werden sich nicht an den Lamellen ablagern, sondern an deren Fuss auf der Innenfläche des Bodens, und das ist ein Bereich, der durch die Lamellen gegen Licht aus der Messkammer abgeschirmt ist. Ausserdem wirken die Lamellen auch als Abschirmung gegen Fremdlicht von aussen, was die Messzuverlässigkeit des erfindungsgemässen Rauchmelders weiter erhöht. The practical use of such scattered light smoke detectors with a flat cylindrical measuring chamber has shown that the frequency of false alarms can increase with increasing duration of use, whereby one of the main reasons for this is that the light from the light source is scattered on dust particles deposited in the measuring chamber and thus the presence is faked by smoke particles. To rule out the occurrence of such false alarms, the detectors must be cleaned of dust from time to time, which is an undesirable additional effort.
The invention is now intended to provide a smoke detector of the type mentioned at the beginning in which the triggering of false alarms due to light scattering on dust particles is avoided as far as possible or at least greatly reduced and an extension of the maintenance intervals is thereby achieved.
The object is achieved according to the invention in that the base is funnel-shaped and has the shape of a cone or a pyramid.
The solution according to the invention brings about a drastic reduction in the interference of dust particles, because they are now much further away from the actual measuring zone than hitherto, as a result of which the probability that light scattered from dust particles reaches the measuring zone has become significantly lower.
As is known, the optical axes of the light source and light receiver intersect in the area of the center of the measuring chamber and thus also the center of the floor. Since the soil is at its greatest distance from the measurement plane in the area of its top or tip, and since dust will predominantly deposit in this area of the floor, it is very unlikely that light emitted by the light source will form a dust particle deposited on the top of the floor arrives and is scattered back into the measuring chamber.
From DE-A-33 34 545 a smoke detector with a truncated cone-shaped base and two light sources is known which has two relatively large openings in the base through which the transmission beams of the two light sources disappear to the outside without reflection. This detector has no labyrinth, because one is not necessary because of the openings mentioned, and it is also of elongated cylindrical shape, the height of the measuring chamber being greater than its diameter. Therefore, the problem of light scattering due to dust particles deposited on the bottom of the measuring chamber does not arise with this detector.
In a first preferred embodiment of the smoke detector according to the invention, the base has a sieve or lattice structure and acts as an insect screen. This embodiment has the advantage that the smoke detector has one component less than before, which is associated with a corresponding cost advantage.
A second preferred embodiment of the smoke detector according to the invention is characterized in that the bottom of its inner surface facing the measuring chamber is provided with a plurality of lamellae projecting vertically upwards, and in that the arrangement, number, height and mutual spacing of these lamellae are selected such that against light falling on the floor hits one of the slats before it hits it, and the light receiver only sees the slats from the floor.
The inventive design of the floor with the slats directed upward further reduces the probability that light from the beam path in the measuring chamber is scattered on dust particles deposited on the floor. This is because the dust particles will not be deposited on the lamellae, but rather on their base on the inner surface of the floor, and this is an area that is lamellarized from light from the measuring chamber. In addition, the slats also act as a shield against external light from the outside, which further increases the measuring reliability of the smoke detector according to the invention.

Ein weiterer wesentlicher Vorteil, der sich aus der erwähnten Absorption des von unerwünschten Sekundärstreuungen oder Reflexionen herrührenden Lichts, des sogenannten Untergrundlichts, ergibt, sind sinkende Anforderungen an die Fertigungstoleranzen. Das heisst, dass mit zunehmender Absorption des Untergrundlichts die Anforderungen an die Positioniergenauigkeit von Lichtquelle und Lichtempfänger sinken.Another significant advantage resulting from the absorption of unwanted Secondary scattering or reflections from light, the so-called Underground light, results in decreasing demands on the manufacturing tolerances. The means that with increasing absorption of the background light the requirements for the Positioning accuracy of light source and light receiver decrease.

Im folgenden wird die Erfindung anhand eines Ausführungsbeispiels und der Zeichnungen näher erläutert; es zeigt:

Fig. 1
einen Querschnitt durch einen Streulichtrauchmelder im Niveau der optischen Achse von dessen Optikmodul, mit Blickrichtung gegen den Boden des Optikmoduls; und
Fig. 2
einen schematischen Schnit nach der Linie II-II von Fig. 1 in einem gegenüber Fig. 1 verkleinerten Massstab.
In the following the invention is explained in more detail using an exemplary embodiment and the drawings; it shows:
Fig. 1
a cross section through a scattered light smoke detector in the level of the optical axis of its optics module, looking towards the bottom of the optics module; and
Fig. 2
a schematic section along the line II-II of Fig. 1 on a reduced scale compared to Fig. 1.

Der dargestellte Streulichtrauchmelder besteht in bekannter Weise aus einem Meldereinsatz 1, der in einem vorzugsweise an der Decke des zu überwachenden Raums montierten Sockel (nicht dargestellt) befestigbar ist, und aus einer über den Meldereinsatz 1 gestülpten Melderhaube 2, die im Bereich ihrer im Betriebszustand des Melders gegen den zu überwachenden Raum gerichteten Kuppe mit Raucheintrittsschlitzen 3 versehen ist. Der Meldereinsatz 1 umfasst im wesentlichen einen schachtelartigen Basiskörper, an dessen der Melderkuppe zugewandter Seite ein von einer Seitenwand 4 umgebenes Optikmodul 5 und an dessen dem Meldersockel zugewandter Seite eine Leiterplatte mit einer Auswerteelektronik (nicht dargestellt) angeordnet sind. Dieser Melderaufbau ist bekannt und wird hier nicht näher beschrieben. Es wird in diesem Zusammenhang beispielsweise auf die Melder der Reihe AlgoRex (AlgoRex - eingetragenes Warenzeichen der Cerberus AG) und auf die europäische Patentanmeldung Nr. 95117405.1 verwiesen.The scattered-light smoke detector shown consists in a known manner of a detector insert 1, which can be fastened in a base (not shown) which is preferably mounted on the ceiling of the room to be monitored, and a detector hood 2 which is placed over the detector insert 1 and which is in the area of its in the operating state of the Detector against the space to be monitored is provided with smoke inlet slots 3. The detector insert 1 essentially comprises a box-like base body, on the side facing the top of the detector an optical module 5 surrounded by a side wall 4 and on the side facing the detector base a printed circuit board with evaluation electronics (not shown) are arranged. This detector structure is known and will not be described in more detail here. In this context, reference is made, for example, to the detectors of the AlgoRex series ( AlgoRex - registered trademark of Cerberus AG) and to European patent application No. 95117405.1.

Das Optikmodul 5 besteht im wesentlichen aus einer Lichtquelle 6, einem Lichtempfänger 7, einer Messkammer 8, einem Labyrinthsystem aus an der Innenseite der Seitenwand 4 angeordneten Peripherieblenden 9, einer zentralen Blende 10 und einem Boden 11. Die optischen Achsen der durch eine Infrarot-Leuchtdiode (IRED) gebildete Lichtquelle 6 und des Lichtempfängers 7 liegen nicht auf einer gemeinsamen Geraden, sondern weisen einen geknickten Verlauf auf, wobei nahe beim Schnittpunkt die zentrale Blende 10 angeordnet ist. Die Seitenwand 4 und der Boden 11 schirmen die Messkammer 8 gegen Fremdlicht von aussen ab, und die Peripherieblenden 9 und die zentrale Blende 10 verhindern, dass Lichtstrahlen auf direktem Weg von der Lichtquelle 6 zum Lichtempfänger 7 gelangen können. Die Peripherieblenden 9 dienen ausserdem zur Unterdrückung des sogenannten Untergrundlichts, welches von unerwünschten Streuungen oder Reflexionen verursacht ist. Je besser das Untergrundlicht unterdrückt wird, desto tiefer ist der Grundpuls, das ist dasjenige Signal, das detektiert wird, wenn in der Messkammer 8 kein Rauch vorhanden ist. Der Schnittbereich des von der Lichtquelle 6 ausgesandten Strahlenbündels und des Gesichtsfeldes des Lichtempfängers 7 bilden den nachfolgend als Streuraum bezeichneten eigentlichen Messbereich.The optics module 5 essentially consists of a light source 6, a light receiver 7, a measuring chamber 8, a labyrinth system on the inside of the side wall 4 arranged peripheral panels 9, a central panel 10 and a bottom 11. The optical axes of the light source formed by an infrared light emitting diode (IRED) 6 and the light receiver 7 are not on a common straight line, but are kinked, with the central one near the intersection Aperture 10 is arranged. The side wall 4 and the bottom 11 shield the measuring chamber 8 against external light from the outside, and the peripheral panels 9 and the central Aperture 10 prevent light rays in a direct path from the light source 6 to Light receiver 7 can get. The peripheral diaphragms 9 are also used for suppression the so-called underground light, which is caused by undesirable scattering or reflections. The better the background light is suppressed, the more the basic pulse is lower, this is the signal that is detected when in the measuring chamber 8 there is no smoke. The intersection of that emitted by the light source 6 Beams and the field of view of the light receiver 7 form the following the actual measuring range referred to as the scattering space.

Die Lichtquelle 6 sendet kurze, intensive Lichtpulse in den Streuraum, wobei der Lichtempfänger 7 zwar den Streuraum, nicht aber die Lichtquelle 6 "sieht". Das Licht der Lichtquelle 6 wird durch in den Streuraum eindringenden Rauch gestreut, und ein Teil dieses Streulichts fällt auf den Lichtempfänger 7. Das dadurch erzeugte Empfänger-Signal wird von der Elektronik verarbeitet. Selbstverständlich kann der Rauchmelder neben dem im Optikmodul 5 enthaltenen optischen Sensorsystem noch weitere Sensoren, beispielsweise einen Temperatur- und/oder einen Gassensor enthalten.The light source 6 sends short, intense light pulses into the scattering space, the light receiver 7 indeed "sees" the scattering space, but not the light source 6. The light of the Light source 6 is scattered by smoke entering the scattering space, and a part this scattered light falls on the light receiver 7. The receiver signal generated thereby is processed by the electronics. Of course, the smoke detector can be next to the optical sensor system contained in the optical module 5, further sensors, for example contain a temperature and / or a gas sensor.

Wenn in dem zu überwachenden Raum Rauch entsteht und zum Rauchmelder aufsteigt, dann dringt er in die Raucheintrittsschlitze 3 und strömt in diesen in horizontaler Richtung an den trichterförmig ausgebildeten Boden 11. Der Boden 11 weist eine sieb- oder gitterartige Struktur auf und ist an seiner Aussenseite mit sternförmig angeordneten Rippen 12 versehen, durch die der Rauch an den Boden herangeführt wird. Dadurch strömt der Rauch in vertikaler Richtung in die Messkammer 8 und in den Streuraum. If smoke arises in the room to be monitored and rises to the smoke detector, then it penetrates into the smoke inlet slots 3 and flows in the horizontal direction to the funnel-shaped bottom 11. The bottom 11 has a sieve or lattice-like structure and is on the outside with star-shaped ribs 12 provided, through which the smoke is brought to the floor. This flows the smoke in the vertical direction into the measuring chamber 8 and into the spreading space.

Durch die trichterförmige Ausbildung weist der Boden 11 von der Messkammer einen wesentlich grösseren Abstand auf als dies bei einem flachen Boden der Fall ist. In die Messkammer 8 eingedrungene Staubpartikel, die das Licht der Lichtquelle 5 streuen und daher wie Rauchpartikel wirken, lagern sich in der Kuppe des Bodens 11 ab und befinden sind dort ausserhalb des Einfallsbereichs der Strahlung der Lichtquelle 6, wodurch der Störeinfluss dieser Rauchpartikel drastisch reduziert wird.Due to the funnel-shaped design, the base 11 has one from the measuring chamber much larger distance than is the case with a flat floor. In the Measuring chamber 8 penetrated dust particles that scatter the light from the light source 5 and therefore act like smoke particles, are deposited in the top of the bottom 11 and are are there outside the area of incidence of the radiation from the light source 6, whereby the interference of these smoke particles is drastically reduced.

Wie den Figuren zu entnehmen ist, weist der trichterförmige Bereich des Bodens 11 die Form einer Pyramide oder eines Pyramidenstumpfes auf, wobei sämtliche Seitenflächen der Pyramide die schon erwähnte sieb- oder gitterartige Struktur haben. In Fig. 1 ist aus Gründen der deutlicheren Erkennbarkeit nur bei einer der Pyramidenflächen eine solche gitterartige Struktur 13 schematisch angedeutet. Die Rippen 12 an der Aussenseite des Bodens 11 sind vorzugsweise entlang der Pyramidenseitenkanten angeordnet.As can be seen from the figures, the funnel-shaped area of the base 11 has the Form a pyramid or a truncated pyramid, with all side surfaces the pyramid have the sieve-like or lattice-like structure already mentioned. 1 is off For the sake of clearer recognition, only one of the pyramid surfaces lattice-like structure 13 schematically indicated. The ribs 12 on the outside of the Bottom 11 are preferably arranged along the pyramid side edges.

Die Wahrscheinlichkeit des Störeinflusses von auf dem Boden 11 abgelagerten Staubpartikeln wird durch eine spezielle Ausbildung des Bodens weiter verringert. Diese besteht darin, dass der Boden 11 an seiner Innenfläche mit einer Vielzahl von vertikal nach oben ragenden Lamellen 14, 15 versehen ist, wobei deren Anordnung, Anzahl, Höhe und gegenseitiger Abstand so gewählt sind, dass aus der Messkammer auf den Boden fallendes Licht vor Erreichen des Bodens auf eine der Lamellen trifft, und dass der Lichtempfänger 7 vom Boden 11 nur die Lamellen 14, 15 sieht.. Dadurch wird die Gefahr der Streuung des Lichts an Staubpartikeln wesentlich geringer, da der Staub viel eher auf dem Boden liegenbleibt, als dass er an den vertikalen Wänden der Lamellen haftet. Zusätzlich zur Abschirmung des Bodens 11 gegen Licht aus der Messkammer 8 schirmen die Lamellen 14, 15 den Lichtempfänger 7 gegen Fremdlicht von aussen ab.The probability of interference from dust particles deposited on the floor 11 is further reduced by special training of the soil. This exists in that the bottom 11 on its inner surface with a variety of vertically upwards projecting slats 14, 15 is provided, their arrangement, number, height and mutual Distance are selected so that something falling from the measuring chamber onto the floor Light hits one of the slats before reaching the floor, and that the light receiver 7 from the floor 11 sees only the slats 14, 15 .. This increases the risk of scattering of light on dust particles much less, since the dust is much closer to the floor remains to adhere to the vertical walls of the slats. additionally to shield the floor 11 against light from the measuring chamber 8 shield the slats 14, 15 the light receiver 7 against external light from the outside.

Darstellungsgemäss sind nicht alle Pyramidenflächen mit Lamellen versehen, sondern nur die der Lichtquelle 6 und die dem Lichtempfänger 7 gegenüberliegende und die zwischen diesen beiden Flächen eingeschlossene Pyramidenfläche. Die der Lichtquelle 6 und dem Lichtempfänger 7 gegenüberliegenden Pyramidenflächen sind mit parallel zur Grundkante der Pyramide orientierten Längslamellen 14 und die zwischen diesen Flächen eingeschlossene Pyramidenfläche ist mit mit mindestens einer Längslamelle 14 und mit mehreren senkrecht zu dieser orientierten Querlamellen 15 versehen. Die Längslamellen 14 verlaufen zumindest annähernd senkrecht zur optischen Achse der gegenüberliegenden Lichtquelle bzw. des gegenüberliegenden Lichtempfängers. Die Querlamellen 15 dienen in erster Linie zur optischen Entkopplung von Lichtquelle 6 und Lichtempfänger 7.As shown, not all pyramid surfaces are provided with lamellas, but only that of the light source 6 and that opposite the light receiver 7 and that between pyramid surface enclosed between these two surfaces. That of the light source 6 and the light receiver 7 opposite pyramid surfaces are parallel to Base edge of the pyramid oriented longitudinal slats 14 and those between these surfaces enclosed pyramid surface is with at least one longitudinal lamella 14 and provided with several transverse lamellae 15 oriented perpendicular to this. The longitudinal slats 14 run at least approximately perpendicular to the optical axis of the opposite one Light source or the opposite light receiver. The cross slats 15 serve primarily for the optical decoupling of light source 6 and light receiver 7th

Der Boden 11, der ebeno wie der ganze Meldereinsatz 1 (mit Ausnahme von Lichtquelle 6 und Lichtempfänger 7) aus einem geeigneten Kunststoff besteht und als Spritzgussteil hergestellt ist, weist an seinem Rand mehrere Einrastorgane auf (nicht dargestellt), die zur lösbaren Verbindung des Bodens 11 mit der Seitenwand 4 des Optikmoduls 5 (Fig. 2) vorgesehen sind.The floor 11, which is the same as the entire detector insert 1 (with the exception of the light source 6 and light receiver 7) consists of a suitable plastic and as an injection molded part is made, has at its edge several snap-in elements (not shown), the for the detachable connection of the base 11 to the side wall 4 of the optical module 5 (FIG. 2) are provided.

Zur noch besseren Absorption von Untergrundlicht weisen zumindest bestimmte Teile des Optikmoduls 5, insbesondere die Peripherieblenden 9, die Zentralblende 10 und die dem Boden 11 gegenüberliegende Decke der Messkammer 8, anstatt der bisher üblichen matten Oberflächen glänzende, d.h. reflektierende, Oberflächen auf. Selbstverständlich können noch weitere Teile oder die gesamte Innenseite des Optikmoduls 5 eine glänzende Oberfläche aufweisen.For even better absorption of background light, at least certain parts have of the optics module 5, in particular the peripheral diaphragms 9, the central diaphragm 10 and the the floor of the measuring chamber 8 opposite the floor 11, instead of the previously usual matt surfaces shiny, i.e. reflective, surfaces on. Of course can still other parts or the entire inside of the optics module 5 a shiny Have surface.

Bisher war man davon ausgegangen, dass Untergrundlicht am besten durch Absorption an matten Flächen vernichtet werden kann, hat aber bei dieser Überlegung übersehen, dass das Licht an den matten Flächen diffus gestreut wird und unkontrolliert in die Messkammer gelangt. Wenn man hingegen glänzende Flächen verwendet, dann wirken diese wie schwarze Spiegel und reflektieren das nicht absorbierte Licht in eine definierte, nicht störende Richtung, beispielsweise auf die benachbarte Peripherieblende. Da die reflektierenden Flächen schwarz sind und daher nur etwa 5% der auftreffenden Strahlung reflektieren, kann diese durch mehrmalige Reflexion zwischen solchen Flächen praktisch vollständig vernichtet werden. Die Herstellung der glänzenden Flächen erfolgt durch ein Spritzwerkzeug, das zumindest an den Flächen, die glänzen sollen, eine geeignete, vorzugsweise polierte, Oberfläche aufweist.So far, it was believed that underground light was best absorbed can be destroyed on matt surfaces, but overlooked this consideration, that the light is diffusely scattered on the matt surfaces and uncontrolled into the measuring chamber arrives. If, on the other hand, you use glossy surfaces, then these work like black mirrors and reflect the non-absorbed light into a defined, not disturbing direction, for example to the neighboring peripheral panel. Because the reflective Surfaces are black and therefore only reflect about 5% of the incident radiation, can be practically complete by repeated reflection between such surfaces be destroyed. The production of the shiny surfaces is done by a Injection mold that is suitable, preferably at least on the surfaces that are to shine polished, surface.

Ein weiteres für die Erhöhung der Messzuverlässigkeit des dargestellten Rauchmelders sehr wesentliches Merkmal besteht darin, dass die Peripherieblenden 9 oder zumindest die meisten von ihnen nicht rotationssymmetrisch sondern so angeordnet sind, dass der Auftreffwinkel des von der Lichtquelle 6 ausgesandten und des vom Lichtempfänger 7 empfangenen Lichtstrahls auf diese Blenden konstant ist. Rotationssymmetrisch angeordnete Peripherieblenden 9 wären solche, die durch Rotation einer Blende um das Zentrum gebildet sind. In Fig. 1 sind die der Lichtquelle 6 und dem Lichtempfänger 7 benachbarten je vier Peripherieblenden 9 nicht rotationssymmetrisch ausgebildet. Der Auftreffwinkel ist dabei so gewählt, dass das auftreffende und nicht absorbierte Licht möglichst oft zwischen den Peripherieblenden 9 reflektiert wird.Another for increasing the measurement reliability of the smoke detector shown very essential feature is that the peripheral panels 9 or at least most of them are not rotationally symmetrical but are arranged so that the Impact angle of that emitted by the light source 6 and that of the light receiver 7 received light beam on these diaphragms is constant. Arranged rotationally symmetrically Peripheral diaphragms 9 would be those that rotate by rotating an aperture around the center are formed. In Fig. 1, those of the light source 6 and the light receiver 7 are adjacent Four peripheral diaphragms 9 each are not rotationally symmetrical. The angle of incidence is chosen so that the incident and not absorbed light as often as possible is reflected between the peripheral diaphragms 9.

Die Peripherieblenden 9 bestehen darstellungsgemäss je aus zwei abgewinkelten Teilflächen, wobei deren gegenseitige Neigung und der Abstand sowie die Länge der Peripherieblenden 9 so gewählt sind, dass das zu den Peripherieblenden 9 abgestrahlte Licht nicht direkt auf die Innenfläche der Seitenwand 4 gelangen kann, sondern in jedem Fall auf eine Peripherieblende 9 trifft und von dieser auf die benachbarte Peripherieblende reflektiert wird. Auch die nicht-rotationssymmetrische Anordnung der Mehrzahl der Peripherieblenden 9 führt zu einer besseren Absorption des Untergrundlichts und damit zu weniger strengen Anforderungen an die Positionier- und Bauteilegenauigkeit von Lichtquelle 6 und Lichtempfänger 7 und zu einem weniger verschmutzungsanfälligen Melder.As shown, the peripheral panels 9 each consist of two angled partial surfaces, their mutual inclination and the distance and the length of the peripheral diaphragms 9 are selected so that the light emitted to the peripheral diaphragms 9 can not get directly onto the inner surface of the side wall 4, but in any case meets a peripheral panel 9 and from this to the adjacent peripheral panel is reflected. The non-rotationally symmetrical arrangement of the majority of the peripheral diaphragms 9 leads to better absorption of the background light and thus less stringent requirements for the positioning and component accuracy of the light source 6 and light receiver 7 and a less pollution-prone detector.

Wie Figur 1 entnommen werden kann, sind die Peripherieblenden 9 an ihrer gegen die Zentralblende 10 gerichteten Innenkante möglichst scharfkantig ausgebildet. Das hat den Vorteil, dass nur wenig Licht auf eine solche scharfe Kante fällt und somit weniger Licht in eine Vielzahl von Richtungen reflektiert wird.As can be seen in FIG. 1, the peripheral covers 9 are against their Central aperture 10 directed inner edge formed as sharp as possible. That has the The advantage that only a little light falls on such a sharp edge and therefore less light is reflected in a variety of directions.

Bei der Herstellung des Spritzgusswerkzeugs durch Erodieren, ist der Schärfe einer Kante durch die Dicke des verwendeten Drahtes eine Grenze gesetzt, die den Anforderungen an die Innenkanten der Peripherieblenden 9 nicht genügt. Beim Meldereinsatz 1 wird die gewünschte Schärfe der Innenkanten dadurch erreicht, dass in das Spritzgusswerkzeug ein Kern eingesetzt wird, der an seiner zur Formung der genannten Innenkanten vorgesehenen Peripherie eine abgestufte (gezahnte oder gezackte) Kontur aufweist. Die einzelnen Abstufungen dieser Kontur liegen innen an den zur Bildung der Peripherieblenden 9 im Spritzgusswerkzeug gebildeten Nuten an und schliessen diese gegen das Zentrum hin ab. Dadurch können zwischen den Nuten des Spritzgusswerkzeugs und den Abstufungen des Kerns sehr scharfe Kanten gebildet werden.When manufacturing the injection mold by eroding, the sharpness is an edge a limit is set by the thickness of the wire used, which meets the requirements to the inner edges of the peripheral panels 9 is not sufficient. When using detector 1, the desired sharpness of the inner edges is achieved by using the injection mold a core is used, which is provided on its for forming the inner edges Periphery has a stepped (serrated or serrated) contour. The single ones Gradations of this contour lie on the inside to form the peripheral diaphragms 9 grooves formed in the injection mold and close them against the center from. This allows between the grooves of the injection mold and the gradations very sharp edges are formed of the core.

Praktische Versuche haben gezeigt, dass die gleichzeitige Verwendung von Peripherieblenden 9 mit scharfen Innenkanten und von Optikmodulteilen (Peripherieblenden 9, Zentralblende 10, Decke der Messkammer 8) mit glänzender Oberfläche zu einer markanten Reduktion des Grundpulses führt, und dass der Melder weniger verstaubungsund betauungsanfällig wird.Practical tests have shown that the simultaneous use of peripheral shutters 9 with sharp inner edges and optical module parts (peripheral covers 9, Central aperture 10, ceiling of the measuring chamber 8) with a shiny surface to a striking Reduction of the basic pulse leads and that the detector is less dusty and becomes susceptible to condensation.

Wie den Figuren weiter entnommen werden kann, sind die Lichtquelle 6 und der Lichtempfänger 7 je in einem Gehäuse 16 bzw. 17 angeordnet. Die beiden Gehäuse 16 und 17, die an die Decke der Messkammer 8 angearbeitet sind, sind nach unten offen und werden an ihrer offenen Seite durch den Boden 11 abgedeckt. An ihrer der Zentralblende 10 zugewandten Frontseite sind die Gehäuse 16 und 17 je durch ein Fenster mit einer Lichtaus- bzw. Lichteintrittsöffnung abgeschlossen. Diese Fenster weisen gegenüber den Gehäusefenstern bekannter Streulichtrauchmelder den Unterschied auf, dass sie einteilig ausgebildet sind. As can be seen from the figures, the light source 6 and the light receiver 7 each arranged in a housing 16 or 17. The two housings 16 and 17, which are worked on the ceiling of the measuring chamber 8, are open at the bottom and are covered on their open side by the floor 11. At her the central aperture 10 facing front are the housing 16 and 17 each through a window with a Light exit or light entry opening completed. These windows face the Housing windows of known scattered-light smoke detectors make the difference that they are in one piece are trained.

Bei den bekannten Streulichtrauchmeldern bestehen die Fenster aus zwei Teilen, von denen der eine an die Decke der Messkammer und der andere an den Boden angearbeitet ist. Beim Aufsetzen des Bodens treten immer wieder Passschwierigkeiten auf und es kommt zur Bildung eines Lichtspalts zwischen den beiden Fensterhälften und damit zu unerwünschten Störungen des Sende- und des Empfangslichts. Bei den einteiligen Gehäusefenstern sind Störungen dieser Art ausgeschlossen und es können keine Probleme mit der Positioniergenauigkeit der beiden Fensterhälften auftreten.In the known scattered-light smoke detectors, the windows consist of two parts, from one worked on the ceiling of the measuring chamber and the other on the floor is. When fitting the floor, there are always problems with fitting and it comes to the formation of a light gap between the two halves of the window and thus unwanted interference in the transmitted and received light. With the one-piece case windows Disruptions of this kind are excluded and no problems can arise occur with the positioning accuracy of the two window halves.

Wie in Fig. 2 beim Fenster 18 des Gehäuses 16 gezeigt ist, sind die obere und die untere Hälfte der einteiligen Fenster in der Art der beiden Schneiden einer Schere gegeneinander versetzt. Dadurch kann das Spritzgusswerkzeug ohne Seitenzug so ausgebildet werden, dass für jede der beiden gegeneinander versetzten Hälften der Lichtaus- und der Lichteintrittsöffnung ein separates Formelement vorgesehen ist, so dass eine genau definierte Form und eine saubere Oberfläche dieser Öffnungen erreicht wird.As shown in Fig. 2 at window 18 of housing 16, the top and bottom are Half of the one-piece windows in the manner of the two cutting edges of scissors against each other added. As a result, the injection molding tool can be designed without side pull, that for each of the two mutually offset halves of the light output and the Light entry opening a separate shaped element is provided, so that a precisely defined Shape and a clean surface of these openings is achieved.

Claims (9)

  1. Smoke alarm having an alarm insert (1) which can be secured in a pedestal and has an optical module (5) which has a light source (6), a light-receiver (7), a measuring chamber (8), a base (11) which covers the said measuring chamber (8), and a labyrinth system having screens (9) arranged on the periphery of the said measuring chamber (8), characterised in that the base (11) is of funnel-shaped construction and has the form of a cone or a pyramid.
  2. Smoke alarm according to claim 1, characterised in that the base (11) has a sieve-shaped or grid-shaped structure (13) and is constructed as an insect grid.
  3. Smoke alarm according to claim 1 or 2, characterised in that the base (11) is provided, on its inner surface facing towards the measuring chamber (8), with a plurality of upwardly projecting lamellae (14, 15), and that the arrangement, number, height and mutual distance of the said lamellae are chosen in such a way that light falling against the base (11) impinges on one of the lamellae (14, 15) before impinging on the said base (11), and that, of the base (11), the light-receiver (7) sees only the lamellae (14, 15).
  4. Smoke alarm according to claim 3, characterised in that the light-receiver (7) is screened by the lamellae (14, 15) against extraneous light penetrating the measuring chamber (8) from outside.
  5. Smoke alarm according to claims 1 and 3, characterised in that the lamellae (14, 15) are oriented so as to be parallel and perpendicular to the basal edge of the respective side faces of the pyramid.
  6. Smoke alarm according to claim 4, characterised in that ribs (12) which are arranged in the form of a star and which form the side walls of smoke-conducting channels are provided on the outside of the base (11).
  7. Smoke alarm according to claim 1 or 2, characterised in that certain parts of the optical module (5) that are critical in respect of the background light, preferably the peripheral screens (9), the central screen (10) and the cover of the measuring chamber (8), which cover lies opposite the base (11), have a glossy surface and are constructed in such a way that the light which is not absorbed is reflected in a defined direction.
  8. Smoke alarm according to claim 1 or 2, characterised in that the peripheral screens (9) are arranged in such a way that the angle of impingement of the light beam emitted by the light source (6), and of the light beam received by the light-receiver (7), on the majority of the said screens is constant.
  9. Smoke alarm according to claim 1 or 2, characterised in that the peripheral screens (9) have as sharp an edge as possible on their front side which is directed towards the central screen (10).
EP96111751A 1996-07-22 1996-07-22 Smoke detector Expired - Lifetime EP0821330B1 (en)

Priority Applications (12)

Application Number Priority Date Filing Date Title
ES96111751T ES2183899T3 (en) 1996-07-22 1996-07-22 . SMOKE READER
DE59609625T DE59609625D1 (en) 1996-07-22 1996-07-22 smoke detector
EP96111751A EP0821330B1 (en) 1996-07-22 1996-07-22 Smoke detector
AT96111751T ATE223604T1 (en) 1996-07-22 1996-07-22 SMOKE DETECTOR
ZA9705811A ZA975811B (en) 1996-07-22 1997-06-30 Smoke detector.
PL97325921A PL184244B1 (en) 1996-07-22 1997-07-15 Smoke detecting fire warning sensor
UA98031427A UA42086C2 (en) 1996-07-22 1997-07-15 Smoke indicator
AU33327/97A AU725418B2 (en) 1996-07-22 1997-07-15 Smoke detector
KR10-1998-0701678A KR100467130B1 (en) 1996-07-22 1997-07-15 Smoke alarm device
CNB971909334A CN1135511C (en) 1996-07-22 1997-07-15 Smoke warning device
RU98107584/09A RU2189080C2 (en) 1996-07-22 1997-07-15 Smoke alarm
PCT/CH1997/000269 WO1998003946A1 (en) 1996-07-22 1997-07-15 Smoke warning device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP96111751A EP0821330B1 (en) 1996-07-22 1996-07-22 Smoke detector

Publications (2)

Publication Number Publication Date
EP0821330A1 EP0821330A1 (en) 1998-01-28
EP0821330B1 true EP0821330B1 (en) 2002-09-04

Family

ID=8223019

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96111751A Expired - Lifetime EP0821330B1 (en) 1996-07-22 1996-07-22 Smoke detector

Country Status (12)

Country Link
EP (1) EP0821330B1 (en)
KR (1) KR100467130B1 (en)
CN (1) CN1135511C (en)
AT (1) ATE223604T1 (en)
AU (1) AU725418B2 (en)
DE (1) DE59609625D1 (en)
ES (1) ES2183899T3 (en)
PL (1) PL184244B1 (en)
RU (1) RU2189080C2 (en)
UA (1) UA42086C2 (en)
WO (1) WO1998003946A1 (en)
ZA (1) ZA975811B (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2259353T3 (en) * 2002-06-20 2006-10-01 Siemens Schweiz Ag SMOKE DETECTOR BY LIGHT DISPERSION.
ATE318000T1 (en) 2002-06-20 2006-03-15 Siemens Schweiz Ag FIRE ALARM
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EP1768074A1 (en) 2005-09-21 2007-03-28 Siemens Schweiz AG Early detection of fires
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DE59609625D1 (en) 2002-10-10
KR20000064238A (en) 2000-11-06
ATE223604T1 (en) 2002-09-15
PL184244B1 (en) 2002-09-30
WO1998003946A1 (en) 1998-01-29
RU2189080C2 (en) 2002-09-10
CN1198236A (en) 1998-11-04
EP0821330A1 (en) 1998-01-28
AU3332797A (en) 1998-02-10
ZA975811B (en) 1998-02-04
CN1135511C (en) 2004-01-21
PL325921A1 (en) 1998-08-17
UA42086C2 (en) 2001-10-15
KR100467130B1 (en) 2005-06-02
ES2183899T3 (en) 2003-04-01

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