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EP0345798A1 - Fire alarm system - Google Patents

Fire alarm system Download PDF

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Publication number
EP0345798A1
EP0345798A1 EP89110449A EP89110449A EP0345798A1 EP 0345798 A1 EP0345798 A1 EP 0345798A1 EP 89110449 A EP89110449 A EP 89110449A EP 89110449 A EP89110449 A EP 89110449A EP 0345798 A1 EP0345798 A1 EP 0345798A1
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EP
European Patent Office
Prior art keywords
fire
sensor
detector
alarm system
fire alarm
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Granted
Application number
EP89110449A
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German (de)
French (fr)
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EP0345798B1 (en
Inventor
Hannes Güttinger
Mark Jäggi
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Cerberus AG
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Cerberus AG
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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

Definitions

  • the invention relates to a fire alarm system according to the preamble of claim 1.
  • Such fire alarm systems are generally known.
  • CH-A-629'905 describes a gas and fire detection system in which fire detectors are connected to a signaling center via lines, the fire detectors having threshold values for the fire phenomena to be detected, and when exceeded, an alarm signal is forwarded to a signaling center.
  • the object of the present invention is to provide a fire alarm system which avoids the disadvantages of the known fire alarm systems and which reduces the susceptibility to false alarms of known fire alarm systems, in particular without impairing the security of the detection of real alarm situations.
  • the switching elements for linking the output signals of the fire sensors can either be arranged in a fire detector or they can be provided in a signal center. Separate switching devices can also be provided for partial areas, for example larger halls or halls.
  • the fire alarm system according to the invention has the significant advantage that, in the presence of people, the sensitivity of the fire detectors can be reduced without reducing security, since people can not only be the cause of false alarms, but can also reliably differentiate between disturbance variables and real alarm situations. Since the false alarm rate strongly depends on the response behavior of the fire detectors, a significant reduction in the false alarm rate can be achieved by changing the response behavior.
  • the fire alarm system according to the invention has the further advantage that even static sources of interference as the cause of false alarms can be switched off.
  • the output signal of the acoustic sensor can be filtered by frequency analysis and a more reliable decision can be made.
  • the fire sensor consists of an ionization chamber and the acoustic sensor consists of a microphone.
  • the acoustic sensor is structurally connected to the fire detector, wherein it is preferably arranged in the housing of the fire detector, in its base or on one of these parts.
  • the acoustic sensor is arranged spatially separate from the fire detector, an acoustic sensor being provided for controlling the sensitivity of one or more fire detectors.
  • the fire detection system can also be designed in such a way that several acoustic sensors are provided for controlling the sensitivity of a fire detector, it also being possible for several acoustic sensors to control a group of fire detectors.
  • the switching elements for changing the sensitivity of the fire detector are designed such that either the output signal of the fire detector is influenced or that the response threshold of the threshold value detector is changed.
  • the switching elements for changing the sensitivity of the fire detectors can preferably be designed such that, after a fire detector has responded, all fire detectors of the same group are switched to full sensitivity.
  • FIG. 1 shows a block diagram of the circuit of a fire alarm system according to the invention.
  • the fire alarm system consists of an ionization fire detector BM, an acoustic sensor 10 and a signaling center SZ connected to the fire detector BM via lines.
  • the fire sensor works according to the ionization principle, and a microphone is used as the acoustic sensor 10.
  • the sensor of the Ionisatios smoke detector BM consists of a measuring chamber KM, in which the air is made electrically conductive (ionized) by a radiation source.
  • the measuring chamber KM is connected in series with a reference chamber KR and both chambers form a voltage divider which is connected to the operating voltage UB via the matching resistor 9.
  • the reference chamber KR is closed, while the measuring chamber KM is accessible to the room air to be monitored.
  • the connection point VP of the voltage divider is connected to an impedance converter 1, the output signal of which is fed to the threshold value detector 2.
  • the threshold detector 2 in turn is functionally connected to a flip-flop 3, which may generate an alarm signal.
  • the chamber flow is reduced.
  • the internal resistance of the measuring chamber KM increases, which causes a shift in the voltage at the connection point VP. If this voltage shift exceeds a predetermined threshold value, the flip-flop 3 is activated via a first impedance converter 1 and the threshold value detector 2, whereby an alarm is triggered.
  • An acoustic is used to control the sensitivity of the fire detector BM Sensor 10, the output signal of which is amplified by a second impedance converter 11 and fed to the threshold value detector 2.
  • the threshold value detector 2 is designed in such a way that it raises the response threshold for triggering an alarm when the output signal of the second impedance converter 11 connected to the acoustic sensor 11 exceeds a certain value, that is to say the occurrence of a disturbance variable, for example the presence of a person or the switching on of a person Machine or the like.
  • An electrical function control and a check of the response sensitivity of the fire detector BM is possible via the measuring point MP3.
  • the voltage between the measuring points MP1 and MP3 can be measured via the matching resistor 9.
  • KR By changing the resistance value of the matching resistor 9, a change in the voltage at the connection point of the chambers KM, KR can be achieved, as a result of which the electrical sensitivity of the fire detector BM is changed. This makes it possible to adapt the response sensitivity of the BM fire detectors to special environmental conditions such as the presence of people, vehicle traffic, etc.
  • a fire detection system in which the signals from the fire sensor KM and the acoustic sensor 10 are linked in switching elements which are arranged in the fire detector BM.
  • the acoustic sensor 10 can be integrated in the fire detector BM, or it can be spatially separated from the fire detector (s).

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  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fire Alarms (AREA)
  • Fire-Detection Mechanisms (AREA)

Abstract

To increase the reliability with respect to false alarms of fire alarm systems, an acoustic sensor (10) is used which outputs electrical signals in dependence on pressure changes in the environment to be monitored and the output signal of which, after amplification, is combined with the output signal, also amplified, of a fire sensor (12). In this arrangement, the sensitivity of the fire detectors (BM) used in the fire alarm system is changed in dependence on the output signal of the acoustic sensor (10), that is to say on the existence of noise sources in the space to be monitored. According to different developments of the fire alarm system according to the invention, the signals can be combined within a fire detector or the signals can be evaluated in a central evaluating unit. <IMAGE>

Description

Die Erfindung betrifft eine Brandmeldeanlage gemäß dem Oberbegriff des Pa­tentanspruchs 1. Solche Brandmeldeanlagen sind allgemein bekannt. Beispiels­weise ist in der CH-A-629'905 eine Gas- und Brandmeldeanlage beschrieben, bei der Brandmelder über Leitungen an eine Signalzentrale angeschlossen sind, wobei die Brandmelder Schwellenwerte für die nachzuweisenden Brandphänomene besitzen, bei deren Überschreitung ein Alarmsignal an eine Signalzentrale weitergeleitet wird.The invention relates to a fire alarm system according to the preamble of claim 1. Such fire alarm systems are generally known. For example, CH-A-629'905 describes a gas and fire detection system in which fire detectors are connected to a signaling center via lines, the fire detectors having threshold values for the fire phenomena to be detected, and when exceeded, an alarm signal is forwarded to a signaling center.

In der genannten CH-A-629'905 wurde vorgeschlagen, den Nachteil der bis dahin bekannten Brandmeldeanlagen, daß die aus Sicherheitsgründen tief anzusetzenden Ansprechschwellen bewirken, daß auch bei vorübergehendem Auf­treten eines Brandphänomens, das möglicherweise gar nicht auf einem Schaden­feuer beruht, ein Alarm ausgelöst wird, dadurch zu beheben, daß ein im Brand­melder bei Überschreitung eines ersten Schwellenwertes auftretendes Vorwarn­signal anfangs nicht selbsthaltend ist und nach einer vorgegeben Zeitverzöge­rung von der Signalzentrale in Selbsthaltung gebracht und weitergeleitet wird und daß ein nach Überschreitung eines zweiten Schwellenwertes auftretendes Alarmsignal sofort in Selbsthaltung gebracht und weitergeleitet wird. Damit sollte ermöglicht werden, zwischen kurzzeitig auftretenden, unerheblichen Störungen und einer echten Alarmsituation sicher zu unterscheiden. Dies mach­te aber die Intervention von Personal erforderlich.In the above-mentioned CH-A-629'905 it was proposed that the disadvantage of the previously known fire alarm systems, that the low response thresholds set for security reasons cause an alarm to be triggered even if a fire phenomenon occurs temporarily, which may not be due to a damage fire is to be remedied by the fact that a warning signal occurring in the fire detector when a first threshold value is exceeded is initially not self-sustaining and is brought into latching and forwarding by the signaling center after a predetermined time delay and that an alarm signal occurring after exceeding a second threshold value is immediately latched and is forwarded. This should make it possible to differentiate reliably between briefly occurring, insignificant faults and a real alarm situation. However, this required the intervention of personnel.

Um auch verschiedenartige Brandtypen (z.B. raucharme Flüssigkeitsbrände, Schwelbrände) sicher erkennen zu können, wurde z.B. in der GB-A-2'043'977 vorgeschlagen, auf unterschiedliche Brandphänomene ansprechende Brandfühler in einer ODER-Schaltung miteinander zu kombinieren. Dadurch wird die Fehl­alarmhäufigkeit jedoch beträchtlich erhöht.In order to be able to reliably detect different types of fire (e.g. low-smoke liquid fires, smoldering fires), e.g. proposed in GB-A-2'043'977 to combine fire sensors which respond to different fire phenomena with one another in an OR circuit. However, this increases the frequency of false alarms considerably.

Um die Fehlalarmanfälligkeit zu verringern, wurden bei solchen bekannten kombinierten Brandmeldern die Brandfühler durch eine UND-Schaltung verbunden (z.B. CH-A-506'147), wodurch jedoch die Empfindlichkeit erheblich vermindert wurde, da ein Alarmsignal nur ausgelöst wird, wenn beide Brandzustände in hinreichender Stärke vorliegen. Um diesen Nachteil zu beseitigen wurde in der CH-A-572'252 vorgeschlagen, die Auswerteschaltung derart auszubilden, daß sie bei einer Beeinflussung des einen Fühlers durch einen Brandzustand die An­sprechschwelle des anderen Fühlers im Sinne einer Empfindlichkeitserhöhung verändert. Eine ähnliche Anordnung wurde in der EP-A-0'076'338 vorgeschlagen.In order to reduce the susceptibility to false alarms, the fire sensors in such known combined fire detectors were connected by an AND circuit (e.g. CH-A-506'147), which, however, significantly reduced the sensitivity, since an alarm signal is only triggered if both fire conditions occur in sufficient strength. In order to eliminate this disadvantage, it was proposed in CH-A-572'252 to design the evaluation circuit in such a way that, when one sensor is influenced by a fire, the response threshold of the other sensor in the sense of an increase in sensitivity changed. A similar arrangement has been proposed in EP-A-0'076'338.

Eine Möglichkeit, die Fehlalarmanfälligkeit von Brandmeldeanlagen zu ver­ringern, würde natürlich darin bestehen, allgemein die Empfindlichkeit der darin enthaltenen Brandmelder herabzusetzen. Dies verbietet sich jedoch aus dem einfachen Grunde, weil dadurch die Gefahr gegeben wäre, daß die Brandmel­der eine echte Alarmsituation nicht oder zu spät melden würden.One way of reducing the false alarm susceptibility of fire detection systems would, of course, be to generally reduce the sensitivity of the fire detectors they contain. However, this is forbidden for the simple reason that there is a danger that the fire detectors would not report a real alarm situation or would report it too late.

Die Aufgabe der vorliegenden Erfindung besteht darin, eine Brandmeldeanlage zu schaffen, welche die Nachteile der bekannten Brandmeldeanlagen vermeidet und welche insbesondere ohne Beeinträchtigung der Sicherheit der Erkennung von echten Alarmsituationen die Fehlalarmanfälligkeit bekannter Brandmeldean­lagen verringert.The object of the present invention is to provide a fire alarm system which avoids the disadvantages of the known fire alarm systems and which reduces the susceptibility to false alarms of known fire alarm systems, in particular without impairing the security of the detection of real alarm situations.

Diese Aufgabe wird bei einer Brandmeldeanlage der eingangs genannten Art durch die kennzeichnenden Merkmale des Patentanspruchs 1 gelöst. Bevorzugte Ausführungsformen der Erfindung und Ausgestaltungen sind in den abhängigen Patentansprüchen definiert.This object is achieved in a fire alarm system of the type mentioned by the characterizing features of claim 1. Preferred embodiments of the invention and refinements are defined in the dependent claims.

Die meisten Störgrößen, welche als Quellen von Fehlalarmen auftreten kön­nen, beruhen auf der Aktivität des Menschen, so etwa Tabakrauchen, Schweißar­beiten (Rauch und Funken), Malerarbeiten (Entwicklung von Lösungsmitteldämpfen), Arbeiten mit Dampf (Feuchtigkeit), Kochen und der Be­trieb von Maschinen und Fahrzeugen (Abgase, Rauch). Überraschenderweise wurde nunmehr gefunden, daß eine erhebliche Verminderung der Fehlalarmrate erzielt wird, ohne daß gleichzeitig eine Erhöhung der Gefahr, daß eine echte Alarmsi­tuation nicht erkannt wird, eintritt, wenn man die Empfindlichkeit der Brand­melder in Abhängigkeit von der Anwesenheit von Menschen oder Maschinen herab­setzt. Die Detektion der Anwesenheit von Menschen und/oder Maschinen kann mittels passiver Infrarot-Detektoren oder - vorzugsweise - mittels akusti­scher Sensoren erfolgen.Most disturbance variables that can occur as sources of false alarms are based on human activity, such as tobacco smoking, welding (smoke and sparks), painting (developing solvent vapors), working with steam (moisture), cooking and operating machinery and vehicles (exhaust gases, smoke). Surprisingly, it has now been found that a significant reduction in the false alarm rate is achieved without an increase in the risk that a real alarm situation is not recognized if the sensitivity of the fire detectors is reduced as a function of the presence of people or machines. The presence of people and / or machines can be detected by means of passive infrared detectors or - preferably - by means of acoustic sensors.

Die Schaltelemente zur Verknüpfung der Ausgangssignale der Brandsensoren können dabei entweder in einem Brandmelder angeordnet sein, oder sie können in einer Signalzentrale vorgesehen sein. Auch können für Teilbereiche, z.B. größere Säle oder Hallen, separate Schaltvorrichtungen vorgesehen sein.The switching elements for linking the output signals of the fire sensors can either be arranged in a fire detector or they can be provided in a signal center. Separate switching devices can also be provided for partial areas, for example larger halls or halls.

Die erfindungsgemäße Brandmeldeanlage hat den wesentlichen Vorteil, daß bei Anwesenheit von Menschen die Reduktion der Empfindlichkeit der Brandmelder ohne Verminderung der Sicherheit erfolgen kann, da der Mensch nicht nur Ursa­che von Fehlalarmen sein kann, sondern auch sicher zwischen Störgrößen und echten Alarmsituationen unterscheiden kann. Da die Fehlalarmrate stark von dem Ansprechverhalten der Branddetektoren abhängt, kann durch eine Verände­rung des Ansprechverhaltens eine wesentliche Reduktion der Fehlalarmrate er­reicht werden.The fire alarm system according to the invention has the significant advantage that, in the presence of people, the sensitivity of the fire detectors can be reduced without reducing security, since people can not only be the cause of false alarms, but can also reliably differentiate between disturbance variables and real alarm situations. Since the false alarm rate strongly depends on the response behavior of the fire detectors, a significant reduction in the false alarm rate can be achieved by changing the response behavior.

Bei Abwesenheit von Menschen oder dem Fehlen von Maschinenlärm wird das System automatisch auf eine hohe Empfindlichkeit geschaltet. Dies wird die Fehlalarmrate kaum erhöhen, da die wesentlichen Quellen für Fehlalarme nicht vorhanden sind.In the absence of people or the absence of machine noise, the system is automatically switched to a high sensitivity. This will hardly increase the false alarm rate since the main sources of false alarms are not available.

Die erfindungsgemäße Brandmeldeanlage hat den weiteren Vorteil, daß auch ruhende Störquellen als Verursacher von Fehlalarmen ausgeschaltet werden kön­nen. Durch Anpassung der akustischen Sensoren an die speziellen Störquellen, die möglicherweise in dem zu überwachenden Raum auftreten, ist es weiter mög­lich, die Fehlalarmrate herabzusetzen. Durch Frequenzanalyse kann das Aus­gangssignal des akustischen Sensors gefiltert werden, und es kann ein zuver­lässigerer Entscheid herbeigeführt werden.The fire alarm system according to the invention has the further advantage that even static sources of interference as the cause of false alarms can be switched off. By adapting the acoustic sensors to the special sources of interference that may occur in the room to be monitored, it is also possible to reduce the false alarm rate. The output signal of the acoustic sensor can be filtered by frequency analysis and a more reliable decision can be made.

Gemäß einer bevorzugten Ausführungsform der Erfindung besteht der Brandsen­sor aus einer Ionisationskammer und der akustische Sensor aus einem Mikrofon.According to a preferred embodiment of the invention, the fire sensor consists of an ionization chamber and the acoustic sensor consists of a microphone.

Gemäß einer weiteren Ausgestaltung der Erfindung ist der akustische Sensor konstruktiv mit dem Brandmelder verbunden, wobei er vorzugsweise im Gehäuse des Brandmelders, in dessen Sockel oder auf einem dieser Teile angeordnet ist.According to a further embodiment of the invention, the acoustic sensor is structurally connected to the fire detector, wherein it is preferably arranged in the housing of the fire detector, in its base or on one of these parts.

Gemäß einer weiteren Ausgestaltung der Erfindung ist der akustische Sonsor räumlich getrennt von dem Brandmelder angeordnet, wobei ein akustischer Sen­sor für die Steuerung der Empfindlichkeit von einem oder mehreren Brandmel­dern vorgesehen ist. Umgekehrt kann die Brandmeldeanlage auch so ausgestaltet sein, daß meherere akustische Sensoren für die Steuerung der Empfindlichkeit eines Brandmelders vorgesehen sind, wobei es auch möglich ist, daß mehrere akustische Sensoren eine Gruppe von Brandmeldern steuern.According to a further embodiment of the invention, the acoustic sensor is arranged spatially separate from the fire detector, an acoustic sensor being provided for controlling the sensitivity of one or more fire detectors. Conversely, the fire detection system can also be designed in such a way that several acoustic sensors are provided for controlling the sensitivity of a fire detector, it also being possible for several acoustic sensors to control a group of fire detectors.

Gemäß weiteren Ausgestaltungen der Erfindung sind die Schaltelemente zur Veränderung der Empfindlichkeit der Brandmelder so ausgelegt, daß entweder das Ausgangssignal des Brandmelders beeinflußt wird oder daß die Ansprech­schwelle des Schwellenwertdetektors verändert wird. Vorzugsweise können die Schaltelemente zur Veränderung der Empfindlichkeit der Brandmelder so ausge­legt sein, daß nach dem Ansprechen eines Brandmelders sämtliche Brandmelder derselben Gruppe auf die volle Empfindlichkeit geschaltet werden.According to further embodiments of the invention, the switching elements for changing the sensitivity of the fire detector are designed such that either the output signal of the fire detector is influenced or that the response threshold of the threshold value detector is changed. The switching elements for changing the sensitivity of the fire detectors can preferably be designed such that, after a fire detector has responded, all fire detectors of the same group are switched to full sensitivity.

Im folgenden werden Ausführungsbeispiele der Erfindung unter Bezugnahme auf die Zeichnung näher erläutert. Die Figur zeigt ein Blockschema der Schaltung einer erfindungsgemäßen Brandmeldeanlage.Exemplary embodiments of the invention are explained in more detail below with reference to the drawing. The figure shows a block diagram of the circuit of a fire alarm system according to the invention.

Die Brandmeldeanlage besteht aus einem Ionisationsbrandmelder BM, einem akustischen Sensor 10 und einer mit dem Brandmelder BM über Leitungen verbun­denen Signalzentrale SZ. Der Brandsensor arbeitet in diesem Beispiel nach dem Ionisationsprinzip, und als akustischer Sensor 10 wird ein Mikrofon verwen­det. Der Fühler des Ionisatios-Rauchmelders BM besteht aus einer Meßkammer KM, in der die Luft durch eine Strahlenquelle elektrisch leitend gemacht (ionisiert) wird. Die Meßkammer KM ist in Reihe mit einer Referenzkammer KR geschaltet und beide Kammern bilden einen Spannungsteiler, welcher über den Anpassungswiderstand 9 mit der Betriebsspannung UB verbunden ist. Die Refe­renzkammer KR, ist geschlossen, während die Meßkammer KM für die zu überwa­chende Raumluft zugänglich ist. Der Verbindungspunkt VP des Spannungsteilers, ist mit einem Impedanzwandler 1 verbunden, dessen Ausgangssignal dem Schwel­lenwertdetektor 2 zugeleitet wird. Der Schwellenwertdetektor 2 seinerseits ist funktionell mit einer Kippstufe 3 verbunden, die gegebenenfalls ein Alarmsignal erzeugt.The fire alarm system consists of an ionization fire detector BM, an acoustic sensor 10 and a signaling center SZ connected to the fire detector BM via lines. In this example, the fire sensor works according to the ionization principle, and a microphone is used as the acoustic sensor 10. The sensor of the Ionisatios smoke detector BM consists of a measuring chamber KM, in which the air is made electrically conductive (ionized) by a radiation source. The measuring chamber KM is connected in series with a reference chamber KR and both chambers form a voltage divider which is connected to the operating voltage UB via the matching resistor 9. The reference chamber KR is closed, while the measuring chamber KM is accessible to the room air to be monitored. The connection point VP of the voltage divider is connected to an impedance converter 1, the output signal of which is fed to the threshold value detector 2. The threshold detector 2 in turn is functionally connected to a flip-flop 3, which may generate an alarm signal.

Dringen Brandaerosole (Verbrennungsprodukte) in die Meßkammer KM ein, so vermindert sich der Kammerstrom. Der Innenwiderstand der Messkammer KM wird größer, was eine Verschiebung der Spannung am Verbindungspunkt VP bewirkt. Überschreitet diese Spannungsverschiebung einen vorbestimmten Schwellenwert, wird über einen ersten Impedanzwandler 1 und den Schwellenwertdetektor 2 die Kippschaltung 3 angesteuert, wodurch Alarm ausgelöst wird.If fire aerosols (combustion products) penetrate the measuring chamber KM, the chamber flow is reduced. The internal resistance of the measuring chamber KM increases, which causes a shift in the voltage at the connection point VP. If this voltage shift exceeds a predetermined threshold value, the flip-flop 3 is activated via a first impedance converter 1 and the threshold value detector 2, whereby an alarm is triggered.

Zur Steuerung der Empfindlichkeit des Brandmelders BM dient ein akustischer Sensor 10, dessen Ausgangssignal von einem zweiten Impedanzwandler 11 verstärkt und dem Schwellenwertdetektor 2 zugeleitet wird. Der Schwellenwert­detektor 2 ist so ausgelegt, daß er die Ansprechschwelle zur Auslösung eines Alarms heraufsetzt, wenn das Ausgangssignal des mit dem akustischen Sensors 11 verbundenen zweiten Impedanzwandlers 11 einen bestimmten Wert überschrei­tet, d.h. das Auftreten einer Störgröße, z.B. die Anwesenheit eines Menschen oder das Einschalten einer Maschine o.ä., anzeigt.An acoustic is used to control the sensitivity of the fire detector BM Sensor 10, the output signal of which is amplified by a second impedance converter 11 and fed to the threshold value detector 2. The threshold value detector 2 is designed in such a way that it raises the response threshold for triggering an alarm when the output signal of the second impedance converter 11 connected to the acoustic sensor 11 exceeds a certain value, that is to say the occurrence of a disturbance variable, for example the presence of a person or the switching on of a person Machine or the like.

Über den Meßpunkt MP3 ist eine elektrische Funktionskontrolle, sowie eine Überprüfung der Ansprechempfindlichkeit des Brandmelders BM möglich. Mit ei­nem speziellen Meßgerät kann die Spannung zwischen den Meßpunkten MP1 und MP3 über dem Anpassungswiderstand 9 gemessen werden. Durch Veränderung des Widerstandswertes des Anpassungswiderstands 9 kann eine Veränderung der Span­nung am Verbindungspunkt der Kammern KM, KR erreicht werden, wodurch die elektrische Empfindlichkeit des Brandmelders BM verändert wird. Es ist da­durch möglich, die Ansprechempfindlichkeit der Brandmelder BM speziellen Um­gebungsbedingungen, wie Anwesenheit von Menschen, Fahrzeugverkehr etc., anzu­passen.An electrical function control and a check of the response sensitivity of the fire detector BM is possible via the measuring point MP3. With a special measuring device, the voltage between the measuring points MP1 and MP3 can be measured via the matching resistor 9. By changing the resistance value of the matching resistor 9, a change in the voltage at the connection point of the chambers KM, KR can be achieved, as a result of which the electrical sensitivity of the fire detector BM is changed. This makes it possible to adapt the response sensitivity of the BM fire detectors to special environmental conditions such as the presence of people, vehicle traffic, etc.

Vorstehend ist eine Ausführungsform einer erfindungsgemäßen Brandmeldeanla­ge beschrieben, bei welcher die Verknüpfung der Signale des Brandsensors KM und des akustischen Sensors 10 in Schaltelementen erfolgt, welche in dem Brandmelder BM angeordnet sind. Dabei kann der akustische Sensor 10 in den Brandmelder BM integriert sein, oder er kann räumlich getrennt von dem, bzw. den Brandmelder(n) angeordnet sein.An embodiment of a fire detection system according to the invention has been described above, in which the signals from the fire sensor KM and the acoustic sensor 10 are linked in switching elements which are arranged in the fire detector BM. The acoustic sensor 10 can be integrated in the fire detector BM, or it can be spatially separated from the fire detector (s).

In der Figur nicht dargestellt ist eine weitere Ausgestaltungsmöglichkeit für die erfindungsgemäße Brandmeldeanlage, bei welcher die Verknüpfung der Ausgangssignale der Brandmelder BM und der akustischen Sensoren 10 in der Signalzentrale erfolgt.Not shown in the figure is a further design option for the fire alarm system according to the invention, in which the output signals of the fire detectors BM and the acoustic sensors 10 are linked in the signal center.

Abwandlungen der vorbeschriebenen Schaltungen für Brandmeldeanlagen sind im Rahmen der Erfindung gemäß den Ansprüchen möglich und dem Fachmann geläufig.Modifications of the above-described circuits for fire alarm systems are possible within the scope of the invention according to the claims and are familiar to the person skilled in the art.

BezugszeichenReference numerals

  • 1 Erster Impedanzwandler1 First impedance converter
  • 2 Schwellenwertdetektor2 threshold detector
  • 3 Kippschaltung3 toggle switch
  • 9 Entkoppelungswiderstand9 decoupling resistor
  • 10 Akustischer Sensor10 Acoustic sensor
  • 11 Zweiter Impedanzwandler11 Second impedance converter
  • BM BrandmelderBM fire detector
  • KM Brandsensor = MeßkammerKM fire sensor = measuring chamber
  • KR ReferenzkammerKR reference chamber
  • MP1 MeßpunktMP1 measuring point
  • MP2 MeßpunktMP2 measuring point
  • UB BetriebsspannungUB operating voltage
  • VP VerbindungspunktVP connection point

Claims (10)

1. Brandmeldeanlage, die aus mindestens einem Brandmelder (BM), einer Si­gnalzentrale (SZ) und Leitungen, welche die Brandmelder (BM) mit der Signal­zentrale (SZ) verbinden, besteht, wobei in dem Brandmelder (BM) ein in Abhän­gigkeit von auftretenden Brandphänomenen ein elektrisches Signal abgebender Brandsensor (12) vorgesehen ist und wobei ferner eine einen Schwellenwertde­tektor (2) umfassende elektrische Auswerteschaltung vorgesehen ist, die bei Überschreitung eines vorbestimmten Schwellenwertes des Brandsensorausgangssi­gnals ein Alarmsignal abgibt, dadurch gekennzeichnet, daß mindestens ein in Abhängigkeit von Druckänderungen der Umgebung elektrische Signale abgebender akustischer Sensor (10) vorgesehen ist, dessen Ausgangssignal nach Verstär­kung in einem Impedanzwandler (11) der Auswerteschaltung zugeleitet wird und daß in der Auswerteschaltung Schaltelemente (2) vorgesehen sind, welche die Empfindlichkeit des Brandmelders (BM) in Abhängigkeit von dem Ausgangssignal des akustischen Sensors (10) verändern.1. Fire alarm system, which consists of at least one fire detector (BM), a signaling center (SZ) and lines that connect the fire detectors (BM) to the signaling center (SZ), with the fire detector (BM) depending on the fire phenomena that occur an electrical signal emitting fire sensor (12) is provided and furthermore an electrical evaluation circuit comprising a threshold value detector (2) is provided, which emits an alarm signal when a predetermined threshold value of the fire sensor output signal is exceeded, characterized in that at least one electrical signal depends on pressure changes in the environment Signals-emitting acoustic sensor (10) is provided, the output signal after amplification in an impedance converter (11) is fed to the evaluation circuit and that switching elements (2) are provided in the evaluation circuit, which the sensitivity of the fire detector (BM) depending on the output signal of the acoustis Chen sensor (10) change. 2. Brandmeldeanlage gemäß Patentanspruch 1, dadurch gekennzeichnet, daß der akustische Sensor (10) konstruktiv mit dem Brandmelder (BM) verbunden ist.2. Fire alarm system according to claim 1, characterized in that the acoustic sensor (10) is structurally connected to the fire detector (BM). 3. Brandmeldeanlage gemäß Patentanspruch 1, dadurch gekennzeichnet, daß der akustische Sensor (10) räumlich getrennt von dem Brandmelder angeordnet ist und daß ein akustischer Sensor (10) mit mehreren Brandmeldern (BM) funktio­nell verbunden ist.3. Fire alarm system according to claim 1, characterized in that the acoustic sensor (10) is arranged spatially separate from the fire detector and that an acoustic sensor (10) with several fire detectors (BM) is functionally connected. 4. Brandmeldeanlage gemäß Patentanspruch 1, dadurch gekennzeichnet, daß der akustische Sensor (10) räumlich getrennt von dem Brandmelder (BM) angeordnet ist und daß mehrere akustische Sensoren (10) mit mindestens einem Brandmelder (BM) funktionell verbunden sind und dessen Empfindlichkeit steuern.4. Fire alarm system according to claim 1, characterized in that the acoustic sensor (10) is spatially separate from the fire detector (BM) and that several acoustic sensors (10) are functionally connected to at least one fire detector (BM) and control its sensitivity. 5. Brandmeldeanlage gemäß einem der Patentansprüche 1 bis 4, dadurch ge­kennzeichnet, daß die Schaltelemente (2), welche die Empfindlichkeit der Brandmelder (BM) verändern, in der Signalzentrale (SZ) angeordnet sind.5. Fire alarm system according to one of the claims 1 to 4, characterized in that the switching elements (2), which change the sensitivity of the fire detector (BM), are arranged in the signal center (SZ). 6. Brandmeldeanlage gemäß einem der Patentansprüche 1 bis 5, dadurch ge­kennzeichnet, daß die Schaltelemente (2) zur Veränderung der Empfindlichkeit der Brandmelder (BM) so ausgelegt sind, daß das Ausgangssignal des Brandsen­sors (12) beeinflußt wird.6. Fire alarm system according to one of the claims 1 to 5, characterized in that the switching elements (2) for changing the sensitivity of the fire detector (BM) are designed so that the output signal of the fire sensor (12) is influenced. 7. Brandmeldeanlage gemäß einem der Patentansprüche 1 bis 5, dadurch ge­kennzeichnet, daß die Schaltelemente (2) zur Veränderung der Empfindlichkeit der Brandmelder (BM) so ausgelegt sind, daß die Ansprechschwelle des Schwel­lenwertdetektors (2) verändert wird.7. Fire alarm system according to one of the claims 1 to 5, characterized in that the switching elements (2) for changing the sensitivity of the fire detector (BM) are designed so that the response threshold of the threshold detector (2) is changed. 8. Brandmeldeanlage gemäß einem der Patentansprüche 1 bis 7, dadurch ge­kennzeichnet, daß der Brandsensor ein optischer Rauchsensor, vorzugsweise ein Streulicht-Rauchsensor ist.8. Fire alarm system according to one of claims 1 to 7, characterized in that the fire sensor is an optical smoke sensor, preferably a scattered light smoke sensor. 9. Brandmeldeanlage gemäß einem der Patentansprüche 1 bis 7, dadurch ge­kennzeichnet, daß der Brandsensor ein Ionisationsrauchsensor (12) , ist.9. Fire alarm system according to one of the claims 1 to 7, characterized in that the fire sensor is an ionization smoke sensor (12). 10. Brandmeldeanlage gemäß einem der Patentansprüche 1 bis 7, dadurch ge­kennzeichnet, daß der Brandsensor ein Wärmemelder ist.10. Fire alarm system according to one of the claims 1 to 7, characterized in that the fire sensor is a heat detector.
EP89110449A 1988-06-10 1989-06-09 Fire alarm system Expired - Lifetime EP0345798B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH2242/88A CH677413A5 (en) 1988-06-10 1988-06-10
CH2242/88 1988-06-10

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EP0345798A1 true EP0345798A1 (en) 1989-12-13
EP0345798B1 EP0345798B1 (en) 1994-07-27

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EP89110449A Expired - Lifetime EP0345798B1 (en) 1988-06-10 1989-06-09 Fire alarm system

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US (1) US4975684A (en)
EP (1) EP0345798B1 (en)
AT (1) ATE109294T1 (en)
CA (1) CA1316234C (en)
CH (1) CH677413A5 (en)
DE (1) DE58908097D1 (en)
NO (1) NO174126C (en)

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Also Published As

Publication number Publication date
EP0345798B1 (en) 1994-07-27
DE58908097D1 (en) 1994-09-01
NO892389L (en) 1989-12-11
ATE109294T1 (en) 1994-08-15
NO174126C (en) 1994-03-16
NO892389D0 (en) 1989-06-09
US4975684A (en) 1990-12-04
CH677413A5 (en) 1991-05-15
CA1316234C (en) 1993-04-13
NO174126B (en) 1993-12-06

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