EP0227320A2 - Détecteur de fumée - Google Patents

Détecteur de fumée Download PDF

Info

Publication number
EP0227320A2
EP0227320A2 EP86309241A EP86309241A EP0227320A2 EP 0227320 A2 EP0227320 A2 EP 0227320A2 EP 86309241 A EP86309241 A EP 86309241A EP 86309241 A EP86309241 A EP 86309241A EP 0227320 A2 EP0227320 A2 EP 0227320A2
Authority
EP
European Patent Office
Prior art keywords
chamber
fire detector
ridge
mesh
plane
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.)
Granted
Application number
EP86309241A
Other languages
German (de)
English (en)
Other versions
EP0227320B1 (fr
EP0227320A3 (en
Inventor
Stephen Henry Ellwood
David Appleby
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.)
Novar Systems Ltd
Original Assignee
Gent Ltd
Caradon Gent Ltd
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 Gent Ltd, Caradon Gent Ltd filed Critical Gent Ltd
Publication of EP0227320A2 publication Critical patent/EP0227320A2/fr
Publication of EP0227320A3 publication Critical patent/EP0227320A3/en
Application granted granted Critical
Publication of EP0227320B1 publication Critical patent/EP0227320B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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

  • This invention relates to a fire detector having a chamber incorporating an optical smoke sensor.
  • Such optical sensors are well known and generally comprise a light emitting diode (LED) as the source and a photodiode as a receiver located in a chamber accessible to smoke from the ambient atmosphere.
  • LED light emitting diode
  • photodiode as a receiver located in a chamber accessible to smoke from the ambient atmosphere.
  • the angle referred to is in a vertical plane when the detector is conventionally mounted on a ceiling and ensures that there is no direct light transmitting path between the source and the receiver. Precautions are taken to reduce spurious reflections from the source reaching the receiver.
  • Fire detectors incorporating such optical sensors present a number of operational difficulties.
  • Smoke usually enters the chamber through a mesh and it is not possible to have a mesh size sufficiently small to prevent entry of tiny insects that can cause light scatter and generate a false alarm.
  • the conventional disposition of the mesh does not provide consistently repeatable detection results from smoke carried in gaseous streams impinging upon the detector from differing directions in the vertical plane. Such differing directions usually result from a variation in the velocity of the streams.
  • An object of the present invention is to provide a fire detector with improved detection performance and having an optical sensor disposed within a chamber so as to minimise false alarms triggered by objects such as insects.
  • a fire detector to be disposed on a mounting surface such as a ceiling, comprising a chamber open to the ambient atmosphere the chamber having a base, a peripheral region of which lies in a single plane preferably parallel with the surface when the detector is mounted thereon, the base being formed inwardly of the peripheral region with a pair of oppositely sloped recesses meeting at a generally central ridge extending across the base laterally of the recesses, an optical source mounted at the end remote from the ridge of one of the recesses with its optimum optical path directed therealong and an optical receiver mounted at the end remote from the ridge of the other recess with its optimum optical path facing therealong, characterised in that said optimum optical paths are each at a different angle to said plane so that the optical axes of the source and the receiver meet at an angle between 170° and 135° at a position within the chamber spaced laterally from the ridge.
  • the fire detector comprises a cup-shaped body 1 to be fixed to a ceiling 2; a chamber base, indicated generally at 3 and a cover structure 4, incorporating a generally flat, annular mesh 5, the structure and the base together defining a chamber 6.
  • the cross sectional area of the openings in the mesh are likely to be less than lmm 2 to exclude many of the insects causing false alarms of fire, however, the mesh size cannot be too small otherwise smoke entry becomes seriously impaired.
  • the body 1 contains a clip-fit box 7 having a pillar 8 having jaws 9 and 10 embracing a radial edge 11 of a printed circuit board 12, the jaws each being provided with flexible electrical wiper connectors 13 for engaging corresponding fixed contacts (not shown) on the board 12.
  • the chamber base 3 is circular and has a flat peripheral region 14 formed with an upstanding wall 15 the upper part of which has an inwardly directed shoulder 16. Inwardly of the region 14 the base has a chordal ridge 17 which is offset from a diameter of the base.
  • the upper surface 18 of the ridge lies in the plane of the upper surface of the region 14 and, as shown in Fig. 3 the ridge is tapered from a narrow end 19 to a wider end 20 and is formed with a similarly tapered central groove 21. It will be understood that the centre line of the groove is not only displaced from a diameter of the base but is also at a small angle, for example, about 2 0 to the diameter.
  • the base slopes away at 22 and 23 to flat parts 24 and 25.
  • a first groove 26 is formed in the slope 22 and flat part 24 to terminate at 27.
  • a second groove 28 is formed in the slope 23 and flat part 25 to terminate at 29.
  • the groove 26 lies on a diametrical line 30 whereas the groove 28 is displaced from this line by an angle A which may be between 3 0 and 12 0 and is preferably between 3 0 and 5 0 or about 4 0 .
  • the angle B between the median line of the groove 26 and the plane containing the region 14 is preferably about 20 0 .
  • the angle C between the median line of the groove 28 and the plane containing the region 14 is preferably about 16 0.
  • the angle between the median lines of the grooves is between 170 0 and 135° and is preferably between 150° and 140 0 .
  • Part circular stepped parts 31 extend around the slopes 22 and 23 to meet the inner perimeter of the region 14.
  • the printed circuit board 12 carries supports 32 and 33 having recesses 34 and 35 of generally cup-shaped formation respectively formed with lips 36 and 37 to be engaged by catches 38 and 39 on the base 3 to lock the latter and the board 12 together.
  • the edge 11 in the board 12 forms part of a recess 40 therein and the lower surface of the base 3 has depending walls 41, 42 and 43 corresponding in size and shape with the periphery of the recess 40 and serving to seal against the board 12 and to accommodate the pillar 8.
  • the recess 34 is in register and in contact with the end 27 of the groove 26 and the recess 35 is in register and in contact with the end 29 of the groove 28.
  • the recess 34 is formed with internal steps 44 and a photodiode (not shown) is located in the bottom of the recess, with its optimum optical path facing, through a double convex plastic lens 45 along the median line of the groove 26.
  • the recess 35 is provided with a light emitting diode 46 having its optimum optical path directed along the median line of the groove 28. These median lines meet at D a position spaced above and laterally from the ridge 17.
  • the diode 46 is preferably of the gallium aluminium arsenide type which emits radiation at a shorter wavelength than those conventionally used (880 mm instead of 950 mm).
  • the supports 32 and 33 carry pairs of pillars 47, 48 and 49, 50 respectively passing through slots 51 and 52 in the base 3.
  • Thermistors 53 are mounted across each pair of pillars, their connections such as 54 passing downwardly to the board 12 holding them in place. It will be noted that the upper parts of the thermistors are level with the shoulder 16 of the wall 15 and they are in contact with the mesh 5.
  • a number of inwardly directed, sloping, buttresses 55 extend radially inwardly of the wall 15; between these buttresses circumferential ridges 56 are formed on the base 3. (These ridges are not shown in Fig. 2.)
  • a plate 57, formed with a recess 58 in register with the recess 40 in the board 12 is in contact with the board at several places (not shown) around its periphery and is locked with the board and the base 3 by a number of arms such as 59 having cranked ends 60 carried by the base and engaging the plate.
  • the base, the board and the plate can be assembled and handled as a single unit.
  • the chamber 6 is closed by a cap 61 having a circumferential wall 62 with an outwardly directed ledge 63 to receive the inner periphery of the mesh 5.
  • the under surface 64 of the cap 61 is formed with a series of part circumferential ridges having surfaces 65a, b, c, d, e and f of decreasing radius centred on the optical centre of the diode 46. These surfaces are also inclined at different angles to the surface 64. To ensure accurate location of the cap 61 the latter is supported on a number of asymmetrically disposed pegs 66 having reduced diameter portions 67 passing into clearance holes (not shown) in the base 3.
  • the cover 4 has a top 68 engaging the upper surface 69 of the cap 61 and having a depending skirt 70 embracing the wall 62 and clamping the inner periphery of the mesh 5 against the ledge 63.
  • the top 68 is formed with a part 71 extending outwardly of the skirt 70 and a number of spaced apart radial fins 72 and increased width ribs 73 linking the top 68 with a circumferential part 74.
  • the fins 72 are each formed with ribs 75 to clamp the outer periphery of the mesh 5 against the shoulder 16 and the buttresses 55.
  • the cover 4 is secured to the base 3 by a series of snap fit members such as 76 having enlarged heads 77 passing through apertures 78 in the base 3. This engagement holds the mesh 5 and the cap 61 locked against the base 3.
  • the plate 56 is formed around its periphery with a number of locking members such as 79 rotationally engageable with members such as 80 on the body 1.
  • the recesses 40 and 58 in the board 12 and plate 57 enable the pillar 8 to be accommodated while rotational movement between the body 1 and the remainder of the detector both locks and unlocks the plate 57 to the body 1 and at the same time engages and disengages the connectors 13.
  • the board 12 and box 7 contain electrical connectors and such circuitry as may be necessary and the box 7 also has terminals (not shown) accessible through the body 1. If desired the board 12 and box 7 could contain the necessary micro computer and other circuitry disclosed in our copending application 8431883.
  • the photodiode in the recess 34 preferably incorporates an infra-red bandpass filter to assist rejection of ambient light level that may enter the chamber 6. Light cannot directly enter the chamber 6 in the sense to fall directly on the photodiode but a low level may penetrate due to multiple reflections.
  • a major feature of this construction is the reduction to a defined standing level of scatter and reflections within the chamber 6 of light from the diode 46 in no smoke conditions.
  • the defined standing level enables periodic or continuous monitoring of the working of the whole sensor.
  • the interior surfaces of the chamber 6 are of a textured black finish to reduce spurious light reflections and these are further reduced by the presence of the parts 31, steps 44, ridges 56 and surfaces 65a-f.
  • the desired low scatter angle of 10 0 (i.e. when the optimum optical paths meet at 170 0 ) has been determined in a series of experiments. In practice we have found considerable advantage over known constructions with scatter angles up to 45 0 . The different angles between these paths and the plane of the region 14 of the base 3 together with the off-centre location of the ridge 17 and the angle A enable a small scatter angle to be achieved whilst preventing direct reception by the photodiode of radiation from the diode 46.
  • the slot 21 helps to prevent spurious scatter by small insects standing on the central part of the surface 18. Should the slot 21 not be present a small insect of a particular size at the centre of the surface 18 will create more scatter than the same insect at the edge of the surface.
  • the provision of the thermistors 53 increases the overall sensitivity of the detector to fires and it also increases the range of types of fire that can be detected.
  • the mesh 5 also acts as a heat collector for the thermistors which are connected in parallel so that, because they are non-linear devices, the one at higher temperature predominates.
  • the fins 72 do not extend across the annular gaps between the ribs 73 and the skirt 70 so that an annular space 81 exposed to the mesh 5 enables hot air to travel around the space 81 and contact the mesh 5 over a larger area thereof so as to reduce any dependence on directional approach on the horizontal plane.

Landscapes

  • 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)
EP86309241A 1985-11-29 1986-11-26 Détecteur de fumée Expired - Lifetime EP0227320B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB858529435A GB8529435D0 (en) 1985-11-29 1985-11-29 Fire detector
GB8529435 1985-11-29

Publications (3)

Publication Number Publication Date
EP0227320A2 true EP0227320A2 (fr) 1987-07-01
EP0227320A3 EP0227320A3 (en) 1988-08-03
EP0227320B1 EP0227320B1 (fr) 1995-01-04

Family

ID=10588985

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86309241A Expired - Lifetime EP0227320B1 (fr) 1985-11-29 1986-11-26 Détecteur de fumée

Country Status (3)

Country Link
EP (1) EP0227320B1 (fr)
DE (1) DE3650197T2 (fr)
GB (1) GB8529435D0 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997004429A1 (fr) * 1995-07-21 1997-02-06 Thorn Security Limited Detecteur de fumee de labyrinthe
WO1997009876A1 (fr) * 1995-09-15 1997-03-20 Norman Rudd Dispositif pesticide
GB2308978A (en) * 1995-09-15 1997-07-16 Norman Rudd A pesticidal device
EP0800153A2 (fr) * 1996-04-01 1997-10-08 Hamamatsu Photonics K.K. Procédé et dispositif de détection de fumée
EP1327966A2 (fr) * 2002-01-11 2003-07-16 Hochiki Corporation Détecteur de fumée à lumière dispersée
FR2928220A1 (fr) * 2008-03-03 2009-09-04 F A R E Soc Par Actions Simpli Detecteur de fumee compact
CN113168753A (zh) * 2018-12-18 2021-07-23 西门子瑞士有限公司 火灾或烟雾报警器

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4099065A (en) * 1976-10-12 1978-07-04 Chloride, Incorporated Smoke detector with chamber for producing eddy currents
WO1984001650A1 (fr) * 1982-10-11 1984-04-26 Cerberus Ag Detecteur de fumee a rayonnement diffuse
GB2137338A (en) * 1983-03-31 1984-10-03 Hochiki Co Scattered light type smoke detector

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4099065A (en) * 1976-10-12 1978-07-04 Chloride, Incorporated Smoke detector with chamber for producing eddy currents
WO1984001650A1 (fr) * 1982-10-11 1984-04-26 Cerberus Ag Detecteur de fumee a rayonnement diffuse
GB2137338A (en) * 1983-03-31 1984-10-03 Hochiki Co Scattered light type smoke detector

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
FIRST INTERNATIONAL CONFERENCE ON OPTICAL FIBRE SENSORS, 26th-28th April 1983, pages 62-66, London, GB; H. GUTTINGER et al.: "Fiber-optic sensors and technology in security systems" *

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997004429A1 (fr) * 1995-07-21 1997-02-06 Thorn Security Limited Detecteur de fumee de labyrinthe
GB2308978B (en) * 1995-09-15 1999-04-28 Norman Rudd A pesticidal device
WO1997009876A1 (fr) * 1995-09-15 1997-03-20 Norman Rudd Dispositif pesticide
GB2308978A (en) * 1995-09-15 1997-07-16 Norman Rudd A pesticidal device
EP0800153A2 (fr) * 1996-04-01 1997-10-08 Hamamatsu Photonics K.K. Procédé et dispositif de détection de fumée
US5898377A (en) * 1996-04-01 1999-04-27 Hamamatsu Photonics K.K. Smoke detecting apparatus and method
EP0800153A3 (fr) * 1996-04-01 1998-05-13 Hamamatsu Photonics K.K. Procédé et dispositif de détection de fumée
EP1327966A2 (fr) * 2002-01-11 2003-07-16 Hochiki Corporation Détecteur de fumée à lumière dispersée
EP1327966A3 (fr) * 2002-01-11 2003-10-15 Hochiki Corporation Détecteur de fumée à lumière dispersée
US6914535B2 (en) 2002-01-11 2005-07-05 Hochiki Corporation Light scattering type smoke sensor
FR2928220A1 (fr) * 2008-03-03 2009-09-04 F A R E Soc Par Actions Simpli Detecteur de fumee compact
WO2009115720A2 (fr) * 2008-03-03 2009-09-24 F.A.R.E Detecteur de fumee compact
CN113168753A (zh) * 2018-12-18 2021-07-23 西门子瑞士有限公司 火灾或烟雾报警器
AT17840U1 (de) * 2018-12-18 2023-04-15 Siemens Schweiz Ag Brand- oder Rauchmelder
US11869327B2 (en) 2018-12-18 2024-01-09 Siemens Schweiz Ag Fire or smoke alarm

Also Published As

Publication number Publication date
EP0227320B1 (fr) 1995-01-04
DE3650197D1 (de) 1995-02-16
EP0227320A3 (en) 1988-08-03
GB8529435D0 (en) 1986-01-08
DE3650197T2 (de) 1995-05-11

Similar Documents

Publication Publication Date Title
AU2003233744B2 (en) Scattered-light smoke detector
US6756905B2 (en) Photoelectric smoke detector and chamber therefor
KR101019839B1 (ko) 화재 탐지기
US5751218A (en) Smoke detector housing for improved smoke collection
US6778091B2 (en) Smoke chamber
US4906978A (en) Optical smoke detector
EP0234312B1 (fr) Détecteur de vol passif à infrarouge installé au plafond avec lentille en forme de dôme
EP0227320A2 (fr) Détecteur de fumée
US4778996A (en) Ceiling mounted passive infrared intrusion detector with pyramidal mirror
US4560874A (en) Reference channel for sensing optical contamination
EP0225173B1 (fr) Détecteur de particules ou de gaz
US5257013A (en) Protecting UV flame detecting apparatus
CN216670897U (zh) 烟雾探测装置
JPS62215849A (ja) 火災検知器
JPS6122278Y2 (fr)
CN111540159B (zh) 一种可定向排除凝露干扰的烟雾报警器及使用方法
JPH0435990Y2 (fr)
EP0233294A1 (fr) Assemblage de cadre d'un detecteur photo-electrique de fumee
EA047064B1 (ru) Устройство обнаружения дыма, датчик рассеянного света устройства обнаружения дыма и способ обнаружения дыма с помощью устройства
GB2342987A (en) Improved smoke dectector with fault monitoring capability
JPH05205173A (ja) 炎式火災感知器
JP2008097649A (ja) 火災感知器

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): CH DE GB LI

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): CH DE GB LI

17P Request for examination filed

Effective date: 19881210

17Q First examination report despatched

Effective date: 19901122

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: CARADON GENT LIMITED

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): CH DE GB LI

REF Corresponds to:

Ref document number: 3650197

Country of ref document: DE

Date of ref document: 19950216

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19961105

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19961106

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 19961114

Year of fee payment: 11

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19971126

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19971130

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19971130

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19971126

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19980801