EP0130558B1 - 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
EP0130558B1
EP0130558B1 EP19840107448 EP84107448A EP0130558B1 EP 0130558 B1 EP0130558 B1 EP 0130558B1 EP 19840107448 EP19840107448 EP 19840107448 EP 84107448 A EP84107448 A EP 84107448A EP 0130558 B1 EP0130558 B1 EP 0130558B1
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Prior art keywords
chamber
longitudinal
air
smoke alarm
ante
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EP19840107448
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German (de)
French (fr)
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EP0130558A1 (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 supplied in a permanent air flow, which are taken from a ventilation duct to be monitored via a pitot tube and fed back to the latter via an outlet tube, the suction tube and the 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 so 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.
  • ionization smoke detector which is preferably used, a fire can be detected long before flames develop or the temperature rises. 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 confirmed 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. for the outside air accessible measuring chamber and a closed reference chamber working in the saturation area 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 148440.
  • CH-PS 486 082 shows a basic version of an ionization fire detector with the two chambers mentioned.
  • the ions with their connecting ions become ten to a thousand times heavier, which changes their traveling speed and thus the ion current.
  • 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 rest 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 flow in the measuring chamber, this influence being dependent on the flow speed 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 may be necessary in the ventilation ducts for control or air conditioning reasons 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 332762.
  • aerodynamic measures alone do not seem to be sufficient, since radiation sources arranged in front of the wind are also 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 2412557, 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 to circumvent the problems outlined for ionization smoke detector inserts of any type which have to be installed in ventilation ducts and for this purpose in a sample chamber, in that the novel air flow in the surrounding area of the smoke detector insert is a result of the novel design of the sample chambers flow device parallel to its axial direction is issued.
  • 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 connects the upper longitudinal chamber.
  • a second longitudinal chamber is arranged below this first 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 that improves the overall effect at least in partial areas 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, with a cross section that is smaller than the cross section of the second longitudinal chamber and that a storage space is arranged at the end facing away from the first longitudinal chamber and behind the circular opening.
  • DE-B-2 846 310 describes a fire alarm device for a room of great height and preferably large volume, in particular a warehouse or factory building.
  • the fire alarm device has a large number of detector units M, which are very high on the ceiling, i.e. at least four meters, in particular ten meters high rooms are arranged.
  • Each detector unit M has an intake pipe 19 which projects vertically downward and through which air is sucked into the detector unit M by means of a fan V.
  • the detector unit consists of a housing 37 with an inside, specially designed detector D, which has air inlet and air outlet openings on its top.
  • a flap 67 arranged in the middle of the detector unit M above the detector D, together with the detector D, divides the interior of the housing 37 into two chambers 71 and 72.
  • the flap 67 is transverse to the conveying direction of the air supplied by the fan V.
  • the fan V is arranged in one chamber (71), so that the conveyed air is forced to enter the inlet openings of the detector, to flow through it and to enter the second chamber 72 through the outlet openings.
  • a bypass valve in the form of the elastic flap 67 is provided.
  • the known fire detection device is, however, constructed in a complex manner.
  • 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 attached 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 towards the center of the duct.
  • the sample chamber 1 With rectangular Ka 2, the sample chamber 1 is to be placed in the middle of the short side so that the air inlet tube 3 or the air outlet tube 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.
  • 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 pre-chamber 7, into which the air inlet pipe 3 opens is formed by one to about 2/3 the height of the sample chamber 1 reaching first vertical partition wall. 8
  • 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 an intermediate wall 9 which adjoins 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 half the length L of the sample chamber 1.
  • a second vertical partition wall 12 which, however, only extends in the upper half of the sample chamber height H, the first longitudinal chamber 10 becomes complete, the second longitudinal chamber 11 partially completed.
  • a second antechamber 13 is delimited by this intermediate wall 12, the length of which is approximately 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.
  • 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)

Description

Die Erfindung bezieht sich auf eine Probenkammer herkömmlicher Grösse zum Einbau eines lonisations-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 supplied in a permanent air flow, which are taken from a ventilation duct to be monitored via a pitot tube and fed back to the latter via an outlet tube, the suction tube and the outlet tube and smoke detector insert are arranged with the same axis direction.

Die Anwendung einer Probenkammer der beschriebenen Art gestattet den Einsatz von lonisations-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 so 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 lonisations-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 bestätigt werden, um die Übertragung kalten Rauches durch die Luftleitungsstränge zu unterbinden.With the ionization smoke detector, which is preferably used, a fire can be detected long before flames develop or the temperature rises. 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 confirmed as quickly as possible in order to prevent the transmission of cold smoke through the air conduit lines.

Der lonisations-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 lonisationskammern 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 lonisationskammern sind in der GB-PS 1 148440 gezeigt und erläutert. Eine Grundausführung eines lonisationsfeuermelders 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. for the outside air accessible measuring chamber and a closed reference chamber working in the saturation area 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 148440. 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 werden die sich mit ihren verbindenden Ionen zehn- bis tausendmal schwerer, wodurch deren Wandergeschwindigkeit und somit auch der lonenstrom 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 the suspended airborne particles, known as aerosols, enter the measuring chamber, the ions with their connecting ions become ten to a thousand times heavier, which changes their traveling speed and thus the ion current. 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 rest 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 Lufströmungen. In die Messkammer eindringende Luft verändert die lonisationsbedingungen 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 Strömungsgeschwindigkeit 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 flow in the measuring chamber, this influence being dependent on the flow speed 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 may be necessary in the ventilation ducts for control or air conditioning reasons 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 332762 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 lonenstromes durch aus der lonisationskammer 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 332762. However, these aerodynamic measures alone do not seem to be sufficient, since radiation sources arranged in front of the wind are also 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 2412557 aufgezeigt wird, besteht darin, den Einfluss einer nicht vermeidbaren Querströmung auf die Intensität des lonenstromes zu beseitigen. Dies wird dadurch erreicht, dass sich die Elektroden in Richtung der möglichen Luftbewegung um ein Vielfaches ihres Abstandes über den lonisierungsbereich hinaus erstrecken, so dass die durch Luftbewegung aus dem lonisierungsbereich hinausgetragenen Ionen von den ausserhalb des normalen lonenstrombereiches liegenden Elektrodenbereich aufgefangen werden.Another possibility, which is shown in DE-AS 2412557, 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 inserts still fluctuations from their rest voltage within the limits mentioned there could arise.

Aufgabe der Erfindung ist es, für lonisations-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 Strömungseinrichtung erteilt wird.The object of the invention is to circumvent the problems outlined for ionization smoke detector inserts of any type which have to be installed in ventilation ducts and for this purpose in a sample chamber, in that the novel air flow in the surrounding area of the smoke detector insert is a result of the novel design of the sample chambers flow device parallel to its axial direction is issued.

Diese Aufgabe wird erfindungsgemäss bei einer eingangs beschriebenen Probenkammer 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 connects the upper longitudinal chamber. A second longitudinal chamber is arranged below this first 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 Brände, zu ermöglichen.This makes it possible, irrespective of the design of the smoke gas detector used, to reduce the influence of a disturbance variable which 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 er ersten Längskammer und hinter der kreisförmigen Öffnung ein Stauraum angeordnet ist.An advantageous measure that improves the overall effect at least in partial areas 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, with a cross section that is smaller than the cross section of the second longitudinal chamber and that a storage space is arranged at the end facing away from the first longitudinal chamber and behind the circular opening.

In der DE-B-2 846 310 ist eine Brandmeldeeinrichtung für einen Raum grosser Höhe und vorzugsweise grossen Volumens, insbesondere eine Lager- oder Fabrikhalle, beschrieben. Die Brandmeldeeinrichtung weist eine Vielzahl von Meldereinheiten M auf, die an der Decke sehr hoher, d.h. mindestens vier Meter, insbesondere zehn Meter hohen Räumen angeordnet sind. Jede Meldereinheit M weist ein senkrecht nach unten ragendes Ansaugrohr 19 auf, durch das mittels eines Ventilators V Luft in die Meldereinheit M gesaugt wird. Die Meldereinheit besteht aus einem Gehäuse 37 mit einem im Inneren angeordneten, besonders ausgebildeten Melder D, der auf seiner Oberseite Lufteintritts- und Luftaustrittsöffnungen aufweist. Ein mittig in der Meldereinheit M über dem Melder D angeordnete Klappe 67 unterteilt zusammen mit dem Melder D den Innenraum des Gehäuses 37 in zwei Kammern 71 und 72. Die Klappe 67 steht quer zur Förderrichtung der vom Ventilator V gelieferten Luft. Der Ventilator V ist in der einen Kammer (71) angeordnet, so dass die geförderte Luft gezwungen wird, in die Eintrittsöffnungen des Melders einzutreten, diesen zu durchströmen und durch die Austrittsöffnungen in die zweite Kammer 72 zu gelangen. Für den Fall, dass trotz des eigens zugeordneten Ventilators V eine erhöhte Luftgeschwindigkeit die Empfindlichkeit des Brandmelder herabsetzen würde, ist ein Beipassventil in Gestalt der elastischen Klappe 67 vorgesehen. Die bekannte Brandmeldeeinrichtung ist damit jedoch aufwendig konstruiert.DE-B-2 846 310 describes a fire alarm device for a room of great height and preferably large volume, in particular a warehouse or factory building. The fire alarm device has a large number of detector units M, which are very high on the ceiling, i.e. at least four meters, in particular ten meters high rooms are arranged. Each detector unit M has an intake pipe 19 which projects vertically downward and through which air is sucked into the detector unit M by means of a fan V. The detector unit consists of a housing 37 with an inside, specially designed detector D, which has air inlet and air outlet openings on its top. A flap 67 arranged in the middle of the detector unit M above the detector D, together with the detector D, divides the interior of the housing 37 into two chambers 71 and 72. The flap 67 is transverse to the conveying direction of the air supplied by the fan V. The fan V is arranged in one chamber (71), so that the conveyed air is forced to enter the inlet openings of the detector, to flow through it and to enter the second chamber 72 through the outlet openings. In the event that an increased air speed would reduce the sensitivity of the fire detector despite the specially assigned fan V, a bypass valve in the form of the elastic flap 67 is provided. The known fire detection device is, however, constructed in a complex manner.

Anhand der einzigen Zeichnung soll im folgenden ein Ausführungsbeispiel einer erfindungsgemässen Einrichtung näher erläutert werden. Die Figut 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 attached 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 towards the center of the duct. With rectangular Ka 2, the sample chamber 1 is to be placed in the middle of the short side so that the air inlet tube 3 or the air outlet tube 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 anschliessend 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 die Hälfte 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 Länge 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 Spalt 17 mit kreisringförmigem 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 pre-chamber 7, into which the air inlet pipe 3 opens is formed by one to about 2/3 the height of the sample chamber 1 reaching first vertical partition wall. 8 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 an intermediate wall 9 which adjoins 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 half the length L of the sample chamber 1. Through a second vertical partition wall 12, which, however, only extends in the upper half 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 delimited by this intermediate wall 12, the length of which is approximately 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 gap 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. 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).
2. A device as claimed in Claim 1, characterised in that the junction from the first ante-chamber (7) to the first longitudinal chamber (10) is provided with the full cross-section of the first longitudinal chamber (10), whereas the junction from the second longitudinal chamber (11) to the second ante-chamber (13) is provided with a cross-section smaller than the cross-section of the second longitudinal chamber (11), and that a pressure chamber (18) is arranged at that end of the first longitudinal chamber (10) remote from the first ante-chamber (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
AT241183A AT378431B (en) 1983-06-30 1983-06-30 SAMPLE CHAMBER OF CONVENTIONAL SIZE FOR INSTALLATION OF AN IONIZATION SMOKE DETECTOR INSERT
AT2411/83 1983-06-30

Publications (2)

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

Family

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)

Families Citing this family (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

Family Cites Families (6)

* 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
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.
DE2846310C3 (en) * 1978-10-24 1982-01-28 Preussag Ag Feuerschutz, 2060 Bad Oldesloe Fire alarm device for a room of great height and preferably large volume, in particular a warehouse or factory hall

Also Published As

Publication number Publication date
ATA241183A (en) 1984-12-15
EP0130558A1 (en) 1985-01-09
DE3466304D1 (en) 1987-10-22
AT378431B (en) 1985-08-12

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