EP0130558B1 - Chambre d'échantillon à grandeur usuelle pour l'installation d'un insert pour alarme de fumée du type ionisation - Google Patents

Chambre d'échantillon à grandeur usuelle pour l'installation d'un insert pour alarme de fumée du type ionisation 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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EP
European Patent Office
Prior art keywords
chamber
longitudinal
air
smoke alarm
ante
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19840107448
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German (de)
English (en)
Other versions
EP0130558A1 (fr
Inventor
Paul Borovka
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
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Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP0130558A1 publication Critical patent/EP0130558A1/fr
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Publication of EP0130558B1 publication Critical patent/EP0130558B1/fr
Expired legal-status Critical Current

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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING SYSTEMS, e.g. PERSONAL 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)

Claims (2)

1. Chambre à échantillon, de taille usuelle, utilisable pour le montage d'un insert de détecteur de fumée à ionisation comportant des ouvertures latérales s'étendant périphériquement pour la circulation de l'air et dans la chambre de mesure duquel se trouvent envoyés, dans un courant d'air permanent, des échantillons d'air qui sont prélevés par l'intermédiaire d'un tube d'aspiration, dans un canal d'air devant être contrôlé et sont envoyés à nouveau à ce canal par l'intermédiaire d'un tube de sortie, le tube d'aspiration, le tube de sortie et l'insert du détecteur de fumée étant disposés de manière à avoir une même direction axiale, caractérisée par le fait que pour l'obtention d'un courant d'air circulant dans la zone enveloppante de la chambre de mesure (14) parallèlement à la direction axiale de l'insert (6) du détecteur de fumée, il est prévu des chambres à air disposées à l'intérieur de la chambre à échantillon (1 ) de telle sorte que le tube d'aspiration (3) débouche dans une première chambre amont (7), à laquelle se raccorde une première chambre longitudinale supérieure (10), qu'au-dessous de cette première chambre longitudinale (10) se trouve disposée une seconde chambre longitudinale (30) qui contient l'insert (6) du détecteur de fumée et est reliée à une seconde chambre amont (13), d'où sort le tube de sortie (4), et que les première et seconde chambres longitudinales (10, 11 ) sont reliées par une ouverture (14) de préférence circulaire, à un collet (15) s'étendant en direction de la seconde chambre longitudinale (11), le collet (15) entourant la partie cylindrique (16) de la chambre de mesure de l'insert (6) du détecteur de fumée en sorte qu'un canal (17) possédant une section transversale en forme d'anneau circulaire se trouve formé, et que les chambres à air possèdent la même largeur que les chambres à échantillons (1 ).
2. Dispositif suivant la revendication 1, caractérisé par le fait que la jonction entre la première chambre amont (7) et la première chambre longitudinale (10) possède la section transversale totale de la première chambre longitudinale (10), mais que la jonction de la seconde chambre longitudinale (11 ) avec la seconde chambre amont (13) possède une section transversale inférieure à la section transversale de la seconde chambre longitudinale (11), et qu'un espace de retenue (18) est prévu sur l'extrémité, située à l'opposé de la première chambre amont (7), de la première chambre longitudinale (10) et en arrière de l'ouverture circulaire (14).
EP19840107448 1983-06-30 1984-06-27 Chambre d'échantillon à grandeur usuelle pour l'installation d'un insert pour alarme de fumée du type ionisation Expired EP0130558B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT2411/83 1983-06-30
AT241183A AT378431B (de) 1983-06-30 1983-06-30 Probenkammer herkoemmlicher groesse zum einbau eines ionisations-rauchmelder-einsatzes

Publications (2)

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

Family

ID=3533864

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19840107448 Expired EP0130558B1 (fr) 1983-06-30 1984-06-27 Chambre d'échantillon à grandeur usuelle pour l'installation d'un insert pour alarme de fumée du type ionisation

Country Status (3)

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

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 (ko) * 2002-05-06 2003-11-12 성호진 보안용 연무 발생 장치
DE102007013295A1 (de) * 2007-03-16 2008-09-18 Aoa Apparatebau Gauting Gmbh Rauchmelder

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 (de) * 1966-11-02 1971-06-16 Hauni Werke Koerber & Co Kg Verfahren und Ionisationsfeuermelder zum Anzeigen von Rauch- oder Verbrennungsgasen in Luft
CH486082A (de) * 1969-05-19 1970-02-15 Cerberus Ag Ionisationsfeuermelder
BE793205A (fr) * 1971-12-30 1973-04-16 Preussag Ag Feuerschutz Avertisseur d'incendie a ionisation
CH554033A (de) * 1973-04-03 1974-09-13 Cerberus Ag Iomisations-feuermelde-einrichtung.
DE2846310C3 (de) * 1978-10-24 1982-01-28 Preussag Ag Feuerschutz, 2060 Bad Oldesloe Brandmeldeeinrichtung für einen Raum großer Höhe und vorzugsweise großen Volumens, insbesondere eine La ger- oder Fabrikhalle

Also Published As

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

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