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WO1998003948A1 - Detecteur de fumee - Google Patents

Detecteur de fumee Download PDF

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Publication number
WO1998003948A1
WO1998003948A1 PCT/CH1997/000271 CH9700271W WO9803948A1 WO 1998003948 A1 WO1998003948 A1 WO 1998003948A1 CH 9700271 W CH9700271 W CH 9700271W WO 9803948 A1 WO9803948 A1 WO 9803948A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
smoke detector
detector according
peripheral
light source
Prior art date
Application number
PCT/CH1997/000271
Other languages
German (de)
English (en)
Inventor
Urs Riedi
Bernhard Durrer
Kurt Hess
Original Assignee
Cerberus Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cerberus Ag filed Critical Cerberus Ag
Priority to KR1019980701585A priority Critical patent/KR20000064237A/ko
Priority to AU33329/97A priority patent/AU725417B2/en
Priority to PL97325923A priority patent/PL325923A1/xx
Publication of WO1998003948A1 publication Critical patent/WO1998003948A1/fr

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
    • G08B17/103—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device
    • G08B17/107—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device for detecting light-scattering due to smoke
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
    • G08B17/11—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using an ionisation chamber for detecting smoke or gas
    • G08B17/113—Constructional details

Definitions

  • the invention relates to a smoke detector with a detector insert which can be fastened in a base and has an optical module which has a light source, a light receiver, a measuring chamber, a central diaphragm, a base and a labyrinth system with diaphragms arranged on the periphery of the measuring chamber.
  • smoke detectors of this type which are referred to as scattered-light smoke detectors, and which may optionally contain a further sensor, for example a temperature sensor, in addition to the optical module
  • the optical module is designed in such a way that disturbing extraneous light cannot penetrate and smoke can very easily penetrate the measuring chamber.
  • the light source and light receiver are arranged in such a way that no light rays can get directly from the source to the receiver. In the presence of smoke particles in the beam path, the light from the light source is scattered thereon and part of this scattered light falls on the light receiver and causes an electrical signal.
  • the false alarm security of such scattered-light smoke detectors depends, among other things, on the fact that light from the light source that is actually scattered only on smoke particles reaches the light receiver, and that the so-called background light, be it extraneous light from outside or on parts of the optical module or on light other than scattered on smoke particles , is suppressed.
  • the background light is suppressed by absorption of the background light at the peripheral diaphragms, these being arranged rotationally symmetrically relative to the center of the measuring chamber.
  • the signal level caused by background light, the so-called basic pulse is still relatively high, and there is a desire for a reduction in the basic pulse.
  • the invention is now intended to provide a smoke detector of the type mentioned in the introduction, in which the basic pulse is significantly reduced compared to the smoke detectors known today.
  • peripheral diaphragms are arranged such that the angle of incidence of the light beam emitted by the light source and that received by the light receiver is constant on the majority of them.
  • a preferred embodiment of the smoke detector according to the invention is characterized in that the above-mentioned angle of incidence and the shape of the peripheral shutters are selected such that the incident and non-absorbed light is reflected as often as possible between the peripheral shutters.
  • FIG. 2 shows a schematic section along the line II-II of FIG. 1 on a scale reduced compared to FIG. 1.
  • the scattered-light smoke detector shown consists in a known manner of a detector insert 1, which can be fastened in a base (not shown) which is preferably mounted on the ceiling of the room to be monitored, and a put the detector hood 2, which is provided with smoke inlet slots 3 in the area of its dome, which is directed towards the room to be monitored when the detector is in the operating state.
  • the detector insert 1 essentially comprises a box-like base body, on the side facing the tip of an optical module 5 surrounded by a side wall 4 and on the side facing the detector base a printed circuit board with evaluation electronics (not shown) are arranged.
  • This detector structure is known and will not be described in more detail here. In this context, reference is made, for example, to the detectors of the AlgoRex series (AlgoRex - registered trademark of Cerberus AG) and to European patent application No. 95117405.1.
  • the optics module 5 essentially consists of a light source 6, a light receiver 7, a measuring chamber 8, a labyrinth system consisting of peripheral diaphragms 9 arranged on the inside of the side wall 4, a central diaphragm 10 and a base 11.
  • the optical axes of the by an infrared light emitting diode (IRED) formed light source 6 and the light receiver 7 do not lie on a common straight line, but have a bent course, the central diaphragm 10 being arranged close to the intersection.
  • IRED infrared light emitting diode
  • the side wall 4 and the bottom 11 shield the measuring chamber 8 against external light from the outside, and the peripheral diaphragms 9 and the central diaphragm 10 prevent light rays from reaching the light receiver 7 in a direct way from the light source 6.
  • the peripheral diaphragms 9 also serve to suppress the so-called background light, which is caused by undesired scattering or reflections. The better the background light is suppressed, the lower the basic pulse, that is the signal that is detected when there is no smoke in the measuring chamber 8.
  • the intersection of the beam of rays emitted by the light source 6 and the field of view of the light receiver 7 form the actual measurement area, hereinafter referred to as the scattering space.
  • the light source 6 sends short, intense light pulses into the scattering space, the light receiver 7 "seeing" the scattering space but not the light source 6.
  • the light of the Light source 6 is scattered by smoke penetrating into the scattering space, and part of this scattered light falls on the light receiver 7.
  • the receiver signal generated thereby is processed by the electronics.
  • the smoke detector can also contain further sensors, for example a temperature and / or a gas sensor.
  • the bottom 11 has a sieve-like or lattice-like structure and is on it Provided on the outside with star-shaped ribs 12, through which the smoke is brought to the floor. As a result, the smoke flows in the vertical direction into the measuring chamber 8 and into the scattering space. Due to the funnel-shaped design, the base 11 is at a considerably greater distance from the measuring chamber than is the case with a flat base.
  • the funnel-shaped region of the base 11 has the shape of a pyramid or a truncated pyramid, all the side surfaces of the pyramid having the sieve-like or lattice-like structure already mentioned.
  • a lattice-like structure 13 is indicated schematically only in one of the pyramid surfaces for reasons of clearer recognition.
  • the ribs 12 on the outside of the base 11 are preferably arranged along the side of the pyramid.
  • the likelihood of interference from dust particles deposited on the floor 11 is further reduced by a special design of the floor.
  • the bottom 11 on its inner surface with a variety of vertically upwards projecting slats 14, 15 is provided, the arrangement, number, height and mutual spacing of which are selected such that light falling from the measuring chamber onto the floor hits one of the slats before reaching the floor, and that the light receiver 7 from the floor 11 only the slats 14, 15 sees.
  • the lamellae 14, 15 shield the light receiver 7 against outside light from outside.
  • not all pyramid surfaces are provided with lamellae, but only that of the light source 6 and that opposite the light receiver 7 and the pyramid surface enclosed between these two surfaces.
  • the pyramid surfaces opposite the light source 6 and the light receiver 7 are provided with longitudinal slats 14 oriented parallel to the base edge of the pyramid and the pyramid surface enclosed between these surfaces is provided with at least one longitudinal slat 14 and with a plurality of transverse slats 15 oriented perpendicularly to this.
  • the longitudinal lamellae 14 run at least approximately perpendicular to the optical axis of the opposite light source or the opposite light receiver.
  • the transverse fins 15 serve primarily for the optical decoupling of light source 6 and light receiver 7.
  • the optical module 5 for even better absorption of background light, at least certain parts of the optical module 5, in particular the peripheral diaphragms 9, the central diaphragm 10 and the the floor of the measuring chamber 8 opposite the floor 11, instead of the hitherto customary matt surfaces, ie, reflective surfaces.
  • other parts or the entire inner surface of the optical module 5 can have a glossy surface.
  • the glossy surfaces are produced by means of an injection mold which has a suitable, preferably polished, surface, at least on the surfaces which are to be shiny.
  • peripheral diaphragms 9 are not arranged rotationally symmetrically but in such a way that the angle of incidence of the light beam emitted by the light source 6 and that received by the light receiver 7 this aperture is constant.
  • Peripheral diaphragms 9 arranged in a rotationally symmetrical manner would be those which are formed by rotating a diaphragm around the center.
  • the four peripheral diaphragms 9 adjacent to the light source 6 and the light receiver 7 are not rotationally symmetrical.
  • the angle of incidence is chosen so that the incident and non-absorbed light is reflected as often as possible between the peripheral diaphragms 9.
  • the peripheral screens 9 each consist of two angled partial surfaces, the mutual inclination and the spacing and the length of the peripheral screens 9 being selected such that the light emitted to the peripheral screens 9 cannot reach the inner surface of the side wall 4 directly, but in each Case strikes a peripheral diaphragm 9 and is reflected by this on the adjacent peripheral diaphragm.
  • the non-rotationally symmetrical arrangement of the plurality of peripheral diaphragms 9 also leads to better absorption of the background light and thus to less stringent requirements for the positioning and component accuracy of light source 6 and light receiver 7 and to a detector that is less susceptible to contamination.
  • peripheral diaphragms 9 are formed as sharp as possible on their inner edge directed against the central diaphragm 10. This has the advantage that only a little light falls on such a sharp edge and therefore less light is reflected in a multitude of directions.
  • the sharpness of an edge is limited by the thickness of the wire used, which does not meet the requirements for the inner edges of the peripheral screens 9.
  • the desired sharpness of the inner edges is achieved by inserting a core into the injection molding tool which has a stepped (serrated or serrated) contour on the periphery provided for shaping said inner edges.
  • the individual steps of this contour lie on the inside of the grooves formed in the injection molding tool to form the peripheral diaphragms 9 and close them off from the center.
  • very sharp edges can be formed between the grooves of the injection molding tool and the gradations of the core.
  • peripheral diaphragms 9 with sharp inner edges and optical module parts (peripheral diaphragms 9, central diaphragm 10, ceiling of the measuring chamber 8) with a glossy surface results in a marbled surface. edge reduction of the basic pulse leads, and that the detector is less susceptible to dust and condensation.
  • the light source 6 and the light receiver 7 are each arranged in a housing 16 and 17, respectively.
  • the two housings 16 and 17, which are worked onto the ceiling of the measuring chamber 8, are open at the bottom and are covered on their open side by the floor 11.
  • the housings 16 and 17 are each closed off by a window with a light exit opening.
  • These windows differ from the housing windows of known scattered-light smoke detectors in that they are made in one piece.
  • the windows consist of two parts, one of which is attached to the ceiling of the measuring chamber and the other to the floor.
  • the floor When fitting the floor, there are repeated difficulties in fitting and there is a gap between the two halves of the window, which in turn leads to undesired disturbances in the transmitted and received light.
  • the one-piece housing windows faults of this type are excluded and there can be no problems with the positioning accuracy of the two window halves.
  • the injection molding tool can be designed without a side pull in such a way that a separate shaped element is provided for each of the two halves of the light emitting and light emitting openings which are offset with respect to one another, so that a precisely defined shape and a clean surface of these openings is achieved.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Fire-Detection Mechanisms (AREA)

Abstract

L'invention concerne un détecteur de fumée comprenant une unité de détection (1) pouvant être fixée dans un socle, avec un module optique. Ce dernier présente une source lumineuse (6), un photorécepteur (7) une chambre de mesure, un diaphragme central (10), un fond (11) et un système de labyrinthe avec des diaphragmes (9) disposés à la périphérie de la chambre de mesure. Ces diaphragmes périphériques (9) sont disposés de sorte que l'angle d'incidence du faisceau lumineux émis par la source lumineuse (6) et reçu par le photorécepteur (7), sur la plupart desdits diaphragmes, soit constant. L'angle d'incidence est sélectionné de sorte que la lumière incidente et non absorbée soit réfléchie le plus souvent possible entre les diaphragmes périphériques (9).
PCT/CH1997/000271 1996-07-22 1997-07-15 Detecteur de fumee WO1998003948A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
KR1019980701585A KR20000064237A (ko) 1996-07-22 1997-07-15 연기 경보 장치
AU33329/97A AU725417B2 (en) 1996-07-22 1997-07-15 Smoke detector
PL97325923A PL325923A1 (en) 1996-07-22 1997-07-15 Smoke detecting fire warning sensor

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP96111753.8 1996-07-22
EP96111753A EP0821332A1 (fr) 1996-07-22 1996-07-22 Détecteur de fumée

Publications (1)

Publication Number Publication Date
WO1998003948A1 true WO1998003948A1 (fr) 1998-01-29

Family

ID=8223021

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CH1997/000271 WO1998003948A1 (fr) 1996-07-22 1997-07-15 Detecteur de fumee

Country Status (7)

Country Link
EP (1) EP0821332A1 (fr)
KR (1) KR20000064237A (fr)
CN (1) CN1198237A (fr)
AU (1) AU725417B2 (fr)
PL (1) PL325923A1 (fr)
WO (1) WO1998003948A1 (fr)
ZA (1) ZA975813B (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6521907B1 (en) * 1999-04-29 2003-02-18 Pittway Corporation Miniature photoelectric sensing chamber
EP1376504B1 (fr) * 2002-06-20 2006-02-22 Siemens Schweiz AG Capteur de fumée par diffusion de lumière
CN104408863A (zh) * 2014-11-05 2015-03-11 中国科学技术大学先进技术研究院 一种双光路火灾烟雾探测烟室

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3345688A1 (de) * 1983-12-16 1985-07-04 Hartwig Dipl.-Ing. 2409 Scharbeutz Beyersdorf Streulicht - rauchmelder
DE4412212A1 (de) * 1993-04-09 1994-10-13 Hochiki Co Lichtstreuender Rauchdetektor mit reduziertem Nullpunkt-Wahrnehmungsniveau
US5400014A (en) * 1993-07-12 1995-03-21 Detection Systems, Inc. Smoke detector with dark chamber

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3345688A1 (de) * 1983-12-16 1985-07-04 Hartwig Dipl.-Ing. 2409 Scharbeutz Beyersdorf Streulicht - rauchmelder
DE4412212A1 (de) * 1993-04-09 1994-10-13 Hochiki Co Lichtstreuender Rauchdetektor mit reduziertem Nullpunkt-Wahrnehmungsniveau
US5400014A (en) * 1993-07-12 1995-03-21 Detection Systems, Inc. Smoke detector with dark chamber

Also Published As

Publication number Publication date
ZA975813B (en) 1998-01-30
CN1198237A (zh) 1998-11-04
PL325923A1 (en) 1998-08-17
EP0821332A1 (fr) 1998-01-28
AU725417B2 (en) 2000-10-12
AU3332997A (en) 1998-02-10
KR20000064237A (ko) 2000-11-06

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