EP0130558A1 - Conventional size sample chamber for assembling an ionisation smoke alarm insert - Google Patents

Conventional size sample chamber for assembling an ionisation smoke alarm insert Download PDF

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Publication number
EP0130558A1
EP0130558A1 EP19840107448 EP84107448A EP0130558A1 EP 0130558 A1 EP0130558 A1 EP 0130558A1 EP 19840107448 EP19840107448 EP 19840107448 EP 84107448 A EP84107448 A EP 84107448A EP 0130558 A1 EP0130558 A1 EP 0130558A1
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Prior art keywords
chamber
longitudinal
air
chambers
smoke detector
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EP19840107448
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German (de)
French (fr)
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EP0130558B1 (en
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Paul Borovka
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Siemens AG
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Siemens 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
    • 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 sample chamber of conventional size for the installation of an ionization smoke detector insert, the measuring chamber of which air samples are fed in a permanent air flow, which are taken from a ventilation duct to be monitored via a pitot tube and fed back via an outlet tube, the suction tube, outlet tube and smoke detector insert are arranged with the same axis direction.
  • sample chamber of the type described allows the use of ionization smoke detector inserts and optical smoke detector inserts to monitor dust-free supply, exhaust and recirculation air ducts in air conditioning and ventilation systems.
  • the sample chamber should be easily accessible, as close as possible to the last air supply point and in the area of a turbulence-free zone on the ventilation duct and should be concentrated towards the center of the duct.
  • the sample chamber In the case of channels with a rectangular cross section, the sample chamber should be arranged in the middle of the short side in such a way that the pitot tube or air inlet tube runs parallel to the long side; in the case of channels with a circular cross section, the pitot tube should represent a diameter.
  • the sample chamber has a prismatic shape with given dimensions.
  • a fire can be detected for a long time occur before flame formation or temperature increase.
  • This early detection enables an early warning so that the fire can be combated with simple means in the initial stage and thus major fire and water damage can be avoided.
  • shut-off devices arranged in the ventilation ducts are actuated as quickly as possible in order to prevent the transmission of cold smoke through the air conduit lines.
  • the ionization smoke detector reacts to visible and invisible smoke containing fire gases or so-called fire aerosols, as occurs in all fires.
  • the penetration of the fire aerosols into the smoke detector insert changes the equilibrium state of a voltage divider consisting of two ionization chambers. It is an open, i.e. measuring chamber accessible to the outside air and a closed reference chamber working in the saturation range and having a chamber current independent of the chamber voltage.
  • the air in both chambers is ionized by two weak radioactive sources.
  • the measuring chamber has two electrodes connected to DC voltage, to which the ions migrate at a speed given by the size of the molecules and the field strength. This results in a certain current-voltage characteristic.
  • the basic physical principle and possible embodiments of ionization chambers are shown and explained in GB-PS 1 148 440.
  • CH-PS 486.082 shows a basic version of an ionization fire detector with the two chambers mentioned.
  • the connecting ions with their connecting ions turn ten to a thousand times more heavily, which increases their traveling speed and thus also the ions current is changed.
  • the aerosol particles also increase the recombination rate so that the flow of current continues to decrease.
  • the current flow or any electrical quantity dependent thereon in particular the rise in the quiescent voltage set at the measuring chamber under normal environmental conditions, can be used as an indicator of the occurrence of fire aerosols in the air samples supplied to the smoke detector.
  • An electronic evaluation circuit signals an alarm to the fire alarm control panel if a set threshold value for the voltage occurring in the measuring chamber is exceeded.
  • the resting voltage is dependent on many environmental influences, in particular on temperature, air humidity and air currents. Air entering the measuring chamber changes the ionization conditions and reduces the smoke sensitivity of the smoke detector.
  • the influence of an air flow on the no-load voltage is due to the fact that the "wind" influences the ion current in the measuring chamber, this influence being dependent on the rate of disturbance and generally being greatest when the air flow occurs perpendicular to the axis of the smoke detector insert.
  • the alarm threshold is sought to be set as low as possible above the quiescent voltage which occurs under normal conditions, a minimum distance being required due to normal tolerable fluctuations in air pollution, in particular with regard to cigarette smoke.
  • the alarm threshold is sought to be set as low as possible above the quiescent voltage which occurs under normal conditions, a minimum distance being required due to normal tolerable fluctuations in air pollution, in particular with regard to cigarette smoke.
  • a very influential factor here are the large differences in flow velocity, which result from control and air conditioning technology Causes in the ventilation ducts may be necessary and thus also occur in the sample chambers arranged in the "bypass".
  • Smoke detectors have therefore been created in which an attempt is made to keep the influence of the transverse flows perpendicular to the axis of the smoke detector on the ion flow small and relatively independent of the flow velocities by means of aerodynamic measures in the measuring chamber itself, such as accumulation and vortex zones. This can be seen from AT-PS 332.762.
  • aerodynamic measures on their own do not seem to be sufficient, since radiation sources arranged “in front of the wind” are additionally provided, so that the decrease in the ion current due to ions blown out of the ionization chamber is compensated for by blowing in additional ions.
  • Another possibility, which is shown in DE-AS 24 12 557, is to eliminate the influence of an unavoidable cross-flow on the intensity of the ion current. This is achieved in that the electrodes extend in the direction of the possible air movement by a multiple of their distance beyond the ionization area, so that the ions carried out of the ionization area by air movement are caught by the electrode area lying outside the normal ion current area.
  • the object of the invention is for ionization smoke detector inserts of any type, which must be installed in ventilation ducts and for this purpose in a sample chamber, to circumvent the problems outlined by the fact that through a novel design of the sample chambers, the air flow as a whole in the area surrounding the smoke detector insert flow direction parallel to its axial direction is given.
  • Such an arrangement which has a very low air resistance coefficient and therefore only very little impedes the secondary air flow flowing through the sample chamber, has air chambers in the interior of the sample chamber, which are arranged in such a way that the pitot tube opens into a first antechamber, to which a first upper longitudinal chamber connects.
  • a second longitudinal chamber which contains the smoke detector insert and is connected to a second antechamber from which the outlet pipe opens.
  • the first and second longitudinal chambers are connected by a preferably circular opening with a collar extending in the direction of the second longitudinal chamber. The collar surrounds the cylindrical measuring chamber part of the smoke detector insert, so that a channel with an annular cross section is formed.
  • the air chambers have the same width as the sample chambers.
  • An advantageous measure which improves the overall effect at least in parts of the flow velocity due to its effect on partial flows, is characterized in that the transition from the first prechamber to the first longitudinal chamber with the full cross section of the first longitudinal chamber, the transition from the second longitudinal chamber to the second prechamber however, a cross section which is smaller than the cross section of the second longitudinal chamber is provided and that a storage space is arranged at the end of the first longitudinal chamber facing away from the first antechamber and behind the circular opening.
  • FIG. 1 shows a vertical sectional view of a sample chamber of conventional size with the features according to the invention.
  • This sample chamber 1 is expediently placed as close as possible to the last air supply point of a ventilation duct 2 in the region of a zone that is as free of turbulence as possible and should be centered on the center of the duct.
  • the sample chamber 1 is to be placed in the middle of the short side in such a way that the air inlet pipe 3 or the air outlet pipe 4, which is parallel to the axis runs parallel to the long side.
  • the sample chamber 1 is to be mounted in such a way that the air inlet pipe 3 or the air outlet pipe 4 represent a diameter.
  • a secondary air flow is permanently removed from the ventilation duct 2 by means of the air inlet pipe 3 designed as a pitot tube, which flows through the housing 5 of the sample chamber 1, which is closed on all sides, and is returned through the air outlet pipe 4 into the ventilation duct 2. Since the conventional sample chambers should have the smallest possible dimensions for various reasons, the installation of the smoke detector insert 6 is only possible in the position shown, in which the direction of its axis coincides with the axial directions of the air inlet pipe 3 and air outlet pipe 4.
  • a first prechamber 7, into which the air inlet pipe 3 opens, is formed by a first vertical intermediate wall 8 reaching up to approximately 2/3 of the height of the sample chamber 1.
  • the length of the first antechamber 7 is advantageously a quarter of the length L of the sample chamber 1.
  • a first upper longitudinal chamber 10 is created by a horizontal intermediate wall 9 adjoining the first intermediate wall 8.
  • a second longitudinal chamber 11 is arranged underneath. The length of the two longitudinal chambers 10, 11 is advantageously approximately a quarter of the length L of the sample chamber 1.
  • the horizontal partition 9 has a centrally arranged, advantageously circular hole 14, on the edge of which a downwardly facing collar 15 is fastened.
  • the smoke detector insert 6 is installed in the position indicated in the second lower longitudinal chamber 11, its axis passing through the center of the circular hole 14.
  • the storage space 18 is formed in the end region of the first upper longitudinal chamber 10 facing away from the first prechamber 7.
  • a cover 19 is provided which can be clamped by screws 20.
  • the horizontal partition 9 with the collar 15 can be lifted off by loosening screws 21.

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  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fire-Detection Mechanisms (AREA)

Abstract

1. A conventional-size sample chamber for the installation of an ionisation smoke alarm insert with laterally-arranged, peripheral openings for the air exchange, the measuring chamber of which is in a permanent air flow supplied with air samples which are withdrawn via a pressure pipe from a ventilating channel to be monitored and are returned to said ventilating channel via an outlet pipe, where suction pipe, outlet pipe and smoke alarm insert are arranged in the same axial direction, characterised in that in order to obtain an air flow directed in parallel to the axial direction of the smoke alarm insert (6) in the environment of the measuring chamber (16), air chambers are arranged in the interior of the sample chamber (1) in such manner that the pressure pipe (3) leads into a first ante-chamber (7) which is adjoined by a first, upper longitudinal chamber (10), that beneath this first longitudinal chamber (10) a second longitudinal chamber (11) is arranged which contains the smoke alarm insert (6) and is connected to a second ante-chamber (13) out of which the outlet pipe (4) leads, and that the first and second longitudinal chambers (10, 11) are connected by a preferably circular opening (14) to a collar (15) which extends in the direction of the second longitudinal chamber (11), where the collar (15) surrounds the cylindrical measuring chamber component (16) of the smoke alarm insert (6) so that a channel (17) having a circular ring-shaped cross-section is formed, and that the air chambers have the same breadth as the sample chambers (1).

Description

Die Erfindung bezieht sich auf eine Probenkammer herkömmlicher Größe zum Einbau eines Ionisations-Rauchmelder-Einsatzes, dessen Meßkammer in einem permanenten Luftstrom Luftproben zugeführt werden, die über ein Staurohr einem zu überwachenden Lüftungskanal entnommen und über ein Austrittsrohr diesem wieder zugeführt werden, wobei Ansaugrohr, Austrittsrohr und Rauchmelder-Einsatz mit gleicher Achsenrichtung angeordnet sind.The invention relates to a sample chamber of conventional size for the installation of an ionization smoke detector insert, the measuring chamber of which air samples are fed in a permanent air flow, which are taken from a ventilation duct to be monitored via a pitot tube and fed back via an outlet tube, the suction tube, outlet tube and smoke detector insert are arranged with the same axis direction.

Die Anwendung einer Probenkammer der beschriebenen Art gestattet den Einsatz von Ionisations-Rauchmelder-Einsätzen und optischen Rauchmelder-Einsätzen zur Überwachung von staubfreien Zu-, Ab- und Umluftkanälen in Klima- und Ventilationsanlagen.The use of a sample chamber of the type described allows the use of ionization smoke detector inserts and optical smoke detector inserts to monitor dust-free supply, exhaust and recirculation air ducts in air conditioning and ventilation systems.

Die Probenkammer soll gut zugänglich, möglichst nahe der letzten luftzuführenden Stelle und im Bereich einer turbulenzfreien Zone am Lüftungskanal angeordnet werden und zur Kanalmitte konzentriert werden. Bei Kanälen mit rechteckigem Querschnitt soll die Probenkammer so in der Mitte der kurzen Seite angeordnet werden, daß das Staurohr bzw. Lufteintrittsrohr parallel zur langen Seite verläuft, bei Kanälen mit kreisförmigem Querschnitt soll das Staurohr einen Durchmesser darstellen. Die Probenkammer weist in der gebräuchlichen Ausführungsform prismatische Form mit gegebenen Abmessungen auf.The sample chamber should be easily accessible, as close as possible to the last air supply point and in the area of a turbulence-free zone on the ventilation duct and should be concentrated towards the center of the duct. In the case of channels with a rectangular cross section, the sample chamber should be arranged in the middle of the short side in such a way that the pitot tube or air inlet tube runs parallel to the long side; in the case of channels with a circular cross section, the pitot tube should represent a diameter. In the common embodiment, the sample chamber has a prismatic shape with given dimensions.

Mit dem vorzugsweise eingesetzten Ionisations-Rauchmelder kann ein Brandausbruch festgestellt werden, lange bevor Flammenbildung oder Temperaturerhöhung auftreten. Diese Früherkennung ermöglicht eine Frühwarnung, so daß der Brand im Anfangsstadium mit einfachen Mitteln bekämpft werden kann und damit größere Brand- und Wasserschäden vermieden werden können. Auch ist es sehr wesentlich, daß in den Lüftungskanälen angeordnete Absperrvorrichtungen raschest betätigt werden, um die Übertragung kalten Rauches durch die Luftleitungsstränge zu unterbinden.With the preferably used ionization smoke detector, a fire can be detected for a long time occur before flame formation or temperature increase. This early detection enables an early warning so that the fire can be combated with simple means in the initial stage and thus major fire and water damage can be avoided. It is also very important that shut-off devices arranged in the ventilation ducts are actuated as quickly as possible in order to prevent the transmission of cold smoke through the air conduit lines.

Der Ionisations-Rauchmelder reagiert auf sichtbaren und unsichtbaren, Brandgase oder sogenannte Brandaerosole enthaltenden Rauch, wie er bei allen Bränden entsteht. Das Eindringen der Brandaerosole in den Rauchmelder-Einsatz verändert den Gleichgewichtszustand eines aus zwei Ionisationskammern bestehenden Spannungsteilers. Es handelt sich um eine offene, d.h. für die Außenluft zugängliche Meßkammer und eine im Sättigungsbereich arbeitende, einen von der Kammerspannung unabhängigen Kammerstrom aufweisende geschlossene Referenzkammer. Die Luft in beiden Kammern wird durch zwei schwache radioaktive Quellen ionisiert. Die Meßkammer weist zwei an Gleichspannung liegende Elektroden auf, zu denen die Ionen mit einer durch die Größe der Moleküle sowie die Feldstärke gegebenen Geschwindigkeit wandern. Es ergibt sich dadurch eine gewisse Strom-Spannungs-Kennlinie. Das physikalische Grundprinzip sowie mögliche Ausführungsformen von Ionisationskammern sind in der GB-PS 1 148 440 gezeigt und erläutert. Eine Grundausführung eines Ionisationsfeuermelders mit den zwei genannten Kammern zeigt die CH-PS 486.082.The ionization smoke detector reacts to visible and invisible smoke containing fire gases or so-called fire aerosols, as occurs in all fires. The penetration of the fire aerosols into the smoke detector insert changes the equilibrium state of a voltage divider consisting of two ionization chambers. It is an open, i.e. measuring chamber accessible to the outside air and a closed reference chamber working in the saturation range and having a chamber current independent of the chamber voltage. The air in both chambers is ionized by two weak radioactive sources. The measuring chamber has two electrodes connected to DC voltage, to which the ions migrate at a speed given by the size of the molecules and the field strength. This results in a certain current-voltage characteristic. The basic physical principle and possible embodiments of ionization chambers are shown and explained in GB-PS 1 148 440. CH-PS 486.082 shows a basic version of an ionization fire detector with the two chambers mentioned.

Treten nun als Aerosole bezeichnete Brandschwebeteilchen in die Meßkammer ein, dann wenden die sich mit ihren verbindenden Ionen zehn- bis tausendmal schwerer, wodurch deren Wandergeschwindigkeit und somit auch der Ionenstrom verändert wird. Die Aerosolteilchen erhöhen auch die Rekombinationsrate, so daß der Stromfluß noch weiter abnimmt. Der Stromfluß bzw. jede von diesem abhängige elektrische Größe, insbesondere der Anstieg der an der Meßkammer bei normalen Umweltbedingungen eingestellten Ruhespannung, können als Indikator für das Auftreten von Brandaerosolen in den dem Rauchmelder zugeführten Luftproben verwendet werden. Eine elektronische Auswerteschaltung signalisiert bei Überschreiten eines eingestellten Schwellwertes für die an der Meßkammer auftretende Spannung Alarm an die Brandmeldezentrale.If suspended particles now known as aerosols enter the measuring chamber, the connecting ions with their connecting ions turn ten to a thousand times more heavily, which increases their traveling speed and thus also the ions current is changed. The aerosol particles also increase the recombination rate so that the flow of current continues to decrease. The current flow or any electrical quantity dependent thereon, in particular the rise in the quiescent voltage set at the measuring chamber under normal environmental conditions, can be used as an indicator of the occurrence of fire aerosols in the air samples supplied to the smoke detector. An electronic evaluation circuit signals an alarm to the fire alarm control panel if a set threshold value for the voltage occurring in the measuring chamber is exceeded.

Die Ruhespannung ist von vielen Umwelteinflüssen abhängig, insbesondere von Temperatur, Luftfeuchtigkeit und Luftströmungen. In die Meßkammer eindringende Luft verändert die Ionisationsbedingungen und reduziert die Rauchempfindlichkeit des Rauchmelders.The resting voltage is dependent on many environmental influences, in particular on temperature, air humidity and air currents. Air entering the measuring chamber changes the ionization conditions and reduces the smoke sensitivity of the smoke detector.

Der Einfluß einer Luftströmung auf die Ruhespannung ist dadurch bedingt, daß der "Wind" den Ionenstrom in der Meßkammer beeinflußt, wobei diese Beeinflussung von der Störmungsgeschwindigkeit abhängt und allgemein bei senkrecht zur Achse des Rauchmelder-Einsatzes auftretender Luftströmung am größten ist.The influence of an air flow on the no-load voltage is due to the fact that the "wind" influences the ion current in the measuring chamber, this influence being dependent on the rate of disturbance and generally being greatest when the air flow occurs perpendicular to the axis of the smoke detector insert.

Zur Erzielung einer guten Melderempfindlichkeit sucht man die Alarmschwelle möglichst niedrig über der bei Normalbedingungen auftretenden Ruhespannung festzulegen, wobei ein durch normale tolerierbare Schwankungen der Luftverunreinigung, insbesondere hinsichtlich Zigarettenrauches, bedingter Mindestabstand erforderlich ist. Hier ist es nun sehr nachteilig, wenn durch einen der aufgezeigten Umwelteinflüsse sehr starke Schwankungen der Ruhespannung verursacht werden. Ein sehr einflußreicher Faktor sind hier die großen Unterschiede in der Strömungsgeschwindigkeit, die aus regelungs- bzw. klimatechnischen Ursachen in den Lüftungskanälen erforderlich sein können und damit auch in den im "Bypass" angeordneten Probekammern auftreten.In order to achieve good detector sensitivity, the alarm threshold is sought to be set as low as possible above the quiescent voltage which occurs under normal conditions, a minimum distance being required due to normal tolerable fluctuations in air pollution, in particular with regard to cigarette smoke. Here it is very disadvantageous if very strong fluctuations in the rest voltage are caused by one of the environmental influences shown. A very influential factor here are the large differences in flow velocity, which result from control and air conditioning technology Causes in the ventilation ducts may be necessary and thus also occur in the sample chambers arranged in the "bypass".

Es sind daher Rauchmelder geschaffen worden, bei denen versucht wird, den Einfluß der senkrecht zur Achse des Rauchmelders auftretenden Querströmungen auf den Ionenstrom durch aerodynamische Maßnahmen in der Meßkammer selbst, wie Stau- und Wirbelzonen gering und relativ unabhängig von den Strömungsgeschwindigkeiten zu halten. Dies ist etwa aus der AT-PS 332.762 ersichtlich. Diese aerodynamischen Maßnahmen scheinen aber für sich allein nicht hinreichend zu sein, da zusätzlich "vor dem Wind" angeordnete Strahlungsquellen vorgesehen werden, so daß die Abnahme des Ionenstromes durch aus der Ionisationskammer hinausgeblasene Ionen durch Einblasen zusätzlicher Ionen kompensiert wird.Smoke detectors have therefore been created in which an attempt is made to keep the influence of the transverse flows perpendicular to the axis of the smoke detector on the ion flow small and relatively independent of the flow velocities by means of aerodynamic measures in the measuring chamber itself, such as accumulation and vortex zones. This can be seen from AT-PS 332.762. However, these aerodynamic measures on their own do not seem to be sufficient, since radiation sources arranged “in front of the wind” are additionally provided, so that the decrease in the ion current due to ions blown out of the ionization chamber is compensated for by blowing in additional ions.

Eine andere Möglichkeit, die in der DE-AS 24 12 557 aufgezeigt wird,besteht darin, den Einfluß einer nicht vermeidbaren Querströmung auf die Intensität des Ionenstromes zu beseitigen. Dies wird dadurch erreicht, daß sich die Elektroden in Richtung der möglichen Luftbewegung um ein Vielfaches ihres Abstandes über den Ionisierungsbereich hinaus erstrecken, so daß die durch Luftbewegung aus dem Ionisierungsbereich hinausgetragenen Ionen von den außerhalb des normalen Ionenstrombereiches liegenden Elektrodenbereich aufgefangen werden.Another possibility, which is shown in DE-AS 24 12 557, is to eliminate the influence of an unavoidable cross-flow on the intensity of the ion current. This is achieved in that the electrodes extend in the direction of the possible air movement by a multiple of their distance beyond the ionization area, so that the ions carried out of the ionization area by air movement are caught by the electrode area lying outside the normal ion current area.

Da aus Platzgründen die herkömmliche Anordnung des Rauchmeldereinsatzes in der Probenkammer so vorgesehen ist, daß seine Meßkammer einer senkrecht zur Achse des Rauchmelder-Einsatzes verlaufenden Luftströmung ausgesetzt ist, konnten bisher sehr hohe Schwankungen der Geschwindigkeit der Querströmung auftreten, so daß auch bei Anwendung der beschriebenen verbesserten Rauchmelder-Einsätze noch Schwankungen von deren Ruhespannung in den dort genannten Grenzen entstehen konnten.Since, for reasons of space, the conventional arrangement of the smoke detector insert in the sample chamber is provided in such a way that its measuring chamber is exposed to an air flow running perpendicular to the axis of the smoke detector insert, very high fluctuations in the speed of the cross flow have so far occurred, so that even when using the described improvements Smoke detector on fluctuations of their rest voltage within the limits mentioned there.

Aufgabe der Erfindung ist es, für Ionisations-Rauchmelder-Einsätze jeglicher Bauart, die in Lüftungskanälen und dazu in einer Probenkammer eingebaut werden müssen, die aufgezeigte Problematik dadurch zu umgehen, daß durch neuartige Ausbildung der Probenkammern dem Luftstrom insgesamt im Umgebungsbereich des Rauchmelder-Einsatzes eine zu dessen Achsrichtung parallele Strömungsrichtung erteilt wird.The object of the invention is for ionization smoke detector inserts of any type, which must be installed in ventilation ducts and for this purpose in a sample chamber, to circumvent the problems outlined by the fact that through a novel design of the sample chambers, the air flow as a whole in the area surrounding the smoke detector insert flow direction parallel to its axial direction is given.

Diese Aufgabe wird erfindungsgemäß bei einer eingangs beschriebenen Probekammer mit den kennzeichnenden Merkmalen des Anspruchs 1 gelöst.This object is achieved according to the invention in a sample chamber described at the outset with the characterizing features of claim 1.

Eine derartige Anordnung, die einen sehr geringen Luftwiderstandsbeiwert aufweist und daher den durch die Probenkammer fließenden Nebenluftstrom nur sehr wenig behindert, weist im Inneren der Probenkammer Luftkammern auf, die so angeordnet sind, daß das Staurohr in eine erste Vorkammer einmündet, an die sich eine erste obere Längskammer anschließt. Unterhalb dieser ersten Längskammer ist eine zweite Längskammer angeordnet, die den Rauchmelder-Einsatz enthält und mit einer zweiten Vorkammer in Verbindung steht, aus der das Austrittsrohr ausmündet. Die erste und zweite Längskammer sind durch eine vorzugsweise kreisförmige Öffnung mit einem sich in Richtung zur zweiten Längskammer erstreckenden Kragen verbunden. Dabei umgibt der Kragen den zylindrischen Meßkammerteil des Rauchmelder-Einsatzes, so daß ein Kanal mit kreisringförmigem Querschnitt gebildet ist. Die Luftkammern weisen die gleiche Breite wie die Probenkammern auf.Such an arrangement, which has a very low air resistance coefficient and therefore only very little impedes the secondary air flow flowing through the sample chamber, has air chambers in the interior of the sample chamber, which are arranged in such a way that the pitot tube opens into a first antechamber, to which a first upper longitudinal chamber connects. Below this first longitudinal chamber there is a second longitudinal chamber which contains the smoke detector insert and is connected to a second antechamber from which the outlet pipe opens. The first and second longitudinal chambers are connected by a preferably circular opening with a collar extending in the direction of the second longitudinal chamber. The collar surrounds the cylindrical measuring chamber part of the smoke detector insert, so that a channel with an annular cross section is formed. The air chambers have the same width as the sample chambers.

Dadurch ist es möglich, unabhängig von der Bauart des verwendeten Rauchgasmelders, den Einfluß einer an sich nicht eliminierbaren Störgröße auf die Anzeigeempfindlichkeit zu reduzieren und damit die Anzeigeempfindlichkeit zu vergleichmäßigen. Damit gelingt es, die Früherkennung von Entstehungsbränden wesentlich zu verbessern und rechtzeitige Maßnahmen gegen die, gerade in großen, mit Klimaanlagen ausgerüsteten Gebäuden meist mit katastrophalen Folgen auftretenden Bränden, zu ermöglichen.This makes it possible, irrespective of the design of the smoke gas detector used, to reduce the influence of a disturbance variable that cannot be eliminated per se on the display sensitivity and thus to make the display sensitivity more uniform. This makes it possible to significantly improve the early detection of incipient fires and to take timely measures against the fires, which usually have catastrophic consequences, especially in large buildings equipped with air conditioning systems.

Eine vorteilhafte Maßnahme, die durch ihre Auswirkung auf Teilströmungen den Gesamteffekt zumindest in Teilbereichen der Strömungsgeschwindigkeit verbessert, ist dadurch gekennzeichnet, daß der Übergang von der ersten Vorkammer zur ersten Längskammer mit dem vollen Querschnitt der ersten Längskammer, der Übergang von der zweiten Längskammer zur zweiten Vorkammer jedoch mit gegenüber dem Querschnitt der zweiten Längskammer niedrigerem Querschnitt vorgesehen ist und daß an dem der ersten Vorkammer abgewandten Ende der ersten Längskammer und hinter der kreisförmigen Öffnung ein Stauraum angeordnet ist.An advantageous measure, which improves the overall effect at least in parts of the flow velocity due to its effect on partial flows, is characterized in that the transition from the first prechamber to the first longitudinal chamber with the full cross section of the first longitudinal chamber, the transition from the second longitudinal chamber to the second prechamber however, a cross section which is smaller than the cross section of the second longitudinal chamber is provided and that a storage space is arranged at the end of the first longitudinal chamber facing away from the first antechamber and behind the circular opening.

Anhand der einzigen Zeichnung soll im folgenden ein Ausführungsbeispiel einer erfindungsgemäßen Einrichtung näher erläutert werden. Die Figur zeigt in einer senkrechten Schnittansicht eine Probenkammer herkömmlicher Größe mit den erfindungsgemäßen Merkmalen.An exemplary embodiment of a device according to the invention will be explained in more detail below with reference to the single drawing. The figure shows a vertical sectional view of a sample chamber of conventional size with the features according to the invention.

Diese Probenkammer 1 wird zweckmäßig möglichst nahe der letzten luftzuführenden Stelle eines Lüftungskanales 2 im Bereich einer möglichst turbulenzfreien Zone angebracht und soll zur Kanalmitte zentriert sein. Bei rechteckigen Kanälen 2 ist die Probenkammer 1 so in die Mitte der kurzen Seite zu setzen, daß das Lufteintrittsrohr 3 bzw. das dazu achsparallele Luftaustrittsrohr 4 parallel zur langen Seite verläuft. Bei Lüftungskanälen 2 mit kreisförmigem Querschnitt soll die Probenkammer 1 so montiert werden, daß das Lufteintrittsrohr 3 bzw. das Luftaustrittsrohr 4 einen Durchmesser darstellen.This sample chamber 1 is expediently placed as close as possible to the last air supply point of a ventilation duct 2 in the region of a zone that is as free of turbulence as possible and should be centered on the center of the duct. In the case of rectangular channels 2, the sample chamber 1 is to be placed in the middle of the short side in such a way that the air inlet pipe 3 or the air outlet pipe 4, which is parallel to the axis runs parallel to the long side. In the case of ventilation ducts 2 with a circular cross section, the sample chamber 1 is to be mounted in such a way that the air inlet pipe 3 or the air outlet pipe 4 represent a diameter.

Aus dem Lüftungskanal 2 wird permanent mittels des als Staurohr ausgebildeten Lufteintrittsrohres 3 ein Nebenluftstrom entnommen, der durch das allseits geschlossene Gehäuse 5 der Probenkammer 1 strömt und durch das Luftaustrittsrohr 4 in den Lüftungskanal 2 zurückgeführt wird. Da die herkömmlichen Probenkammern aus diversen Gründen möglichst geringe Abmessungen aufweisen sollen, ist der Einbau des Rauchmelder-Einsatzes 6 nur in der gezeigten Lage möglich, in der die Richtung seiner Achse mit den Achsrichtungen von Lufteintrittsrohr 3 und Luftaustrittsrohr 4 übereinstimmt.A secondary air flow is permanently removed from the ventilation duct 2 by means of the air inlet pipe 3 designed as a pitot tube, which flows through the housing 5 of the sample chamber 1, which is closed on all sides, and is returned through the air outlet pipe 4 into the ventilation duct 2. Since the conventional sample chambers should have the smallest possible dimensions for various reasons, the installation of the smoke detector insert 6 is only possible in the position shown, in which the direction of its axis coincides with the axial directions of the air inlet pipe 3 and air outlet pipe 4.

Erfindungsgemäß sind nun durch Zwischenwände gebildete Luftkammern angeordnet, deren Breite gleich der Breite der Probenkammer 1 ist, die senkrecht zur Zeichnungsebene anzunehmen ist. Eine erste Vorkammer 7, in die das Lufteintrittsrohr 3 mündet, ist durch eine bis etwa zu 2/3 der Höhe der Probenkammer 1 reichende erste vertikale Zwischenwand 8 gebildet. Die Länge der ersten Vorkammer 7 beträgt vorteilhaft ein Viertel der Länge L der Probenkammer 1. Durch eine an die erste Zwischenwand 8 anschließende horizontale Zwischenwand 9 wird eine erste obere Längskammer 10 geschaffen. Darunterliegend ist eine zweite Längskammer 11 angeordnet. Die Länge der beiden Längskammern 10, 11 beträgt vorteilhaft etwa ein Viertel der Länge L der Probenkammer 1. Durch eine zweite vertikale Zwischenwand 12, die sich jedoch nur im oberen halben Bereich der Probenkammerhöhe H erstreckt, wird die erste Längskammer 10 vollständig, die zweite Längskammer 11 teilweise abgeschlossen. Zugleich wird durch diese Zwischenwand 12 eine zweite Vorkammer 13 abgegrenzt, der Lange etwa ein Viertel der Länge L der Probenkammer 1 beträgt und die mit der zweiten Längskammer 11 in Verbindung steht. Aus dieser zweiten Vorkammer 13 mündet nach unten das Luftaustrittsrohr 4 aus. Die horizontale Zwischenwand 9 weist ein mittig angeordnetes, vorteilhaft kreisrundes Loch 14 auf, an dessen Umrandung ein nach unten weisender Kragen 15 befestigt ist. In der zweiten unteren Längskammer 11 ist der Rauchmelder-Einsatz 6 in der bezeichneten Lage eingebaut, wobei seine Achse durch den Mittelpunkt des kreisförmigen Loches 14 geht. Es ergibt sich somit zwischen dem Kragen 15 und dem Meßkammerteil 16 des Rauchmelder-Einsatzes 6 ein zylindrischer Spalte 17 mit kreisringförmigen Querschnitt. In dem der ersten Vorkammer 7 abgewandten Endbereich der ersten oberen Längskammer 10 ist der Stauraum 18 ausgebildet. Um den Ein- und Ausbau des Rauchmelder-Einsatzes 6 sowie andere Manipulationen zu ermöglichen, ist ein Deckel 19 vorgesehen, der durch Schrauben 20 festklemmbar ist. Die horizontale Zwischenwand 9 mit dem Kragen 15 ist durch Lösen von Schrauben 21 abhebbar.According to the invention, air chambers formed by partition walls are now arranged, the width of which is equal to the width of the sample chamber 1, which is assumed to be perpendicular to the plane of the drawing. A first prechamber 7, into which the air inlet pipe 3 opens, is formed by a first vertical intermediate wall 8 reaching up to approximately 2/3 of the height of the sample chamber 1. The length of the first antechamber 7 is advantageously a quarter of the length L of the sample chamber 1. A first upper longitudinal chamber 10 is created by a horizontal intermediate wall 9 adjoining the first intermediate wall 8. A second longitudinal chamber 11 is arranged underneath. The length of the two longitudinal chambers 10, 11 is advantageously approximately a quarter of the length L of the sample chamber 1. Through a second vertical partition wall 12, which, however, only extends in the upper half region of the sample chamber height H, the first longitudinal chamber 10 becomes complete, the second longitudinal chamber 11 partially completed. At the same time, a second antechamber 13 is removed from this intermediate wall 12 limited, the length is about a quarter of the length L of the sample chamber 1 and which is connected to the second longitudinal chamber 11. From this second antechamber 13, the air outlet pipe 4 opens downwards. The horizontal partition 9 has a centrally arranged, advantageously circular hole 14, on the edge of which a downwardly facing collar 15 is fastened. The smoke detector insert 6 is installed in the position indicated in the second lower longitudinal chamber 11, its axis passing through the center of the circular hole 14. This results in a cylindrical column 17 with an annular cross section between the collar 15 and the measuring chamber part 16 of the smoke detector insert 6. The storage space 18 is formed in the end region of the first upper longitudinal chamber 10 facing away from the first prechamber 7. In order to enable the installation and removal of the smoke detector insert 6 as well as other manipulations, a cover 19 is provided which can be clamped by screws 20. The horizontal partition 9 with the collar 15 can be lifted off by loosening screws 21.

Claims (2)

1. Probenkammer herkömmlicher Größe zum Einbau eines Ionisations-Rauchmelder-Einsatzes, dessen Meßkammer in einem permanenten Luftstrom Luftproben zugeführt werden, die über ein Staurohr einem zu überwachenden Lüftungskanal entnommen und über ein Austrittsrohr diesem wieder zugeführt werden, wobei Ansaugrohr, Austrittsrohr und Rauchmelder-Einsatz mit gleicher Achsenrichtung angeordnet sind,
dadurch gekennzeichnet, daß zur Erzielung eines im Umgebungsbereich der Meßkammer (16) parallel zur Achsenrichtung des Rauchmelder-Einsatzes (6) verlaufenden Luftstromes im Inneren der Probenkammer (1) Luftkammern derart angeordnet sind, daß das Staurohr (3) in eine erste Vorkammer (7) einmündet, an die sich eine erste obere Längskammer (10) anschließt, daß unterhalb dieser ersten Längskammer (10) eine zweite Längskammer (11) angeordnet ist, die den Rauchmelder-Einsatz (6) enthält und mit einer zweiten Vorkammer (13) in Verbindung steht, aus der das Austrittsrohr (4) ausmündet und daß erste und zweite Längskammer (10, 11) durch eine vorzugsweise kreisförmige Öffnung (14) mit einem sich in Richtung zur zweiten Längskammer (11) erstreckenden Kragen (15) verbunden sind, wobei der Kragen (15) den zylindrischen Meßkammerteil (16) des Rauchmelder-Einsatzes (6) umgibt, so daß ein Kanal (17) mit kreisringförmigen Querschnitt gebildet ist, und daß die Luftkammern die gleiche Breite wie die Probenkammern (1) aufweisen.1.Sample chamber of conventional size for the installation of an ionization smoke detector insert, the measuring chamber of which air samples are fed in a permanent air flow, which are taken from a ventilation duct to be monitored via a pitot tube and fed back via an outlet tube, the suction tube, outlet tube and smoke detector insert being used are arranged with the same axis direction,
characterized in that in order to achieve an air flow in the vicinity of the measuring chamber (16) parallel to the axis direction of the smoke detector insert (6), air chambers are arranged in the interior of the sample chamber (1) in such a way that the pitot tube (3) enters a first antechamber (7 ) opens, to which a first upper longitudinal chamber (10) adjoins that a second longitudinal chamber (11) is arranged below this first longitudinal chamber (10), which contains the smoke detector insert (6) and with a second prechamber (13) in Connection is made, from which the outlet pipe (4) opens and that the first and second longitudinal chambers (10, 11) are connected by a preferably circular opening (14) with a collar (15) extending in the direction of the second longitudinal chamber (11), whereby the collar (15) surrounds the cylindrical measuring chamber part (16) of the smoke detector insert (6), so that a channel (17) is formed with an annular cross section, and that the air chambers have the same width as the sample have chambers (1). 2. Einrichtung nach Anspruch 1,
dadurch gekennzeichnet, daß der Übergang von der ersten Vorkammer (7) zur ersten Längskammer (10) mit dem vollen Querschnitt der ersten Längskammer (10), der Übergang von der zweiten Längskammer (11) zur zweiten Vorkammer (13) jedoch mit gegenüber dem Querschnitt der zweiten Längskammer (11) niedrigerem Querschnitt vorgesehen ist und daß an dem der ersten Vorkammer (7) abgewandten Ende der ersten Längskammer (10) und hinter der kreisförmigen Öffnung (14) ein Stauraum (18) angeordnet ist.2. Device according to claim 1,
characterized in that the transition from the first prechamber (7) to the first longitudinal chamber (10) has the full cross-section of the first longitudinal chamber (10), but the transition from the second longitudinal chamber (11) to the second prechamber (13) is also opposite the cross section of the second longitudinal chamber (11) with a lower cross section is provided and that a storage space (18) is arranged at the end of the first longitudinal chamber (10) facing away from the first antechamber (7) and behind the circular opening (14).
EP19840107448 1983-06-30 1984-06-27 Conventional size sample chamber for assembling an ionisation smoke alarm insert Expired EP0130558B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT2411/83 1983-06-30
AT241183A AT378431B (en) 1983-06-30 1983-06-30 SAMPLE CHAMBER OF CONVENTIONAL SIZE FOR INSTALLATION OF AN IONIZATION SMOKE DETECTOR INSERT

Publications (2)

Publication Number Publication Date
EP0130558A1 true EP0130558A1 (en) 1985-01-09
EP0130558B1 EP0130558B1 (en) 1987-09-16

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ID=3533864

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19840107448 Expired EP0130558B1 (en) 1983-06-30 1984-06-27 Conventional size sample chamber for assembling an ionisation smoke alarm insert

Country Status (3)

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EP (1) EP0130558B1 (en)
AT (1) AT378431B (en)
DE (1) DE3466304D1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4758827A (en) * 1986-07-28 1988-07-19 Adt, Inc. Duct smoke detector
KR20030086743A (en) * 2002-05-06 2003-11-12 성호진 Fog Generator for Home and Office Security
DE102007013295A1 (en) * 2007-03-16 2008-09-18 Aoa Apparatebau Gauting Gmbh smoke detector

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1148440A (en) * 1965-10-18 1969-04-10 Micro Tek Instr Corp Apparatus and method for ionization detection
DE1648928A1 (en) * 1966-11-02 1971-06-16 Hauni Werke Koerber & Co Kg Method and ionization fire alarm for indicating smoke or combustion gases in air
DE2846310B2 (en) * 1978-10-24 1981-05-27 Preussag Ag Feuerschutz, 2060 Bad Oldesloe Fire alarm device for a room of great height, and preferably of large volume, in particular a warehouse or factory hall

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH486082A (en) * 1969-05-19 1970-02-15 Cerberus Ag Ionization fire alarms
BE793205A (en) * 1971-12-30 1973-04-16 Preussag Ag Feuerschutz IONIZATION FIRE ALARM
CH554033A (en) * 1973-04-03 1974-09-13 Cerberus Ag IOMIZATION FIRE DETECTION DEVICE.

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1148440A (en) * 1965-10-18 1969-04-10 Micro Tek Instr Corp Apparatus and method for ionization detection
DE1648928A1 (en) * 1966-11-02 1971-06-16 Hauni Werke Koerber & Co Kg Method and ionization fire alarm for indicating smoke or combustion gases in air
DE2846310B2 (en) * 1978-10-24 1981-05-27 Preussag Ag Feuerschutz, 2060 Bad Oldesloe Fire alarm device for a room of great height, and preferably of large volume, in particular a warehouse or factory hall

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4758827A (en) * 1986-07-28 1988-07-19 Adt, Inc. Duct smoke detector
KR20030086743A (en) * 2002-05-06 2003-11-12 성호진 Fog Generator for Home and Office Security
DE102007013295A1 (en) * 2007-03-16 2008-09-18 Aoa Apparatebau Gauting Gmbh smoke detector

Also Published As

Publication number Publication date
EP0130558B1 (en) 1987-09-16
DE3466304D1 (en) 1987-10-22
ATA241183A (en) 1984-12-15
AT378431B (en) 1985-08-12

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