EP0021671A1 - Détecteur de fumée - Google Patents

Détecteur de fumée Download PDF

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Publication number
EP0021671A1
EP0021671A1 EP80301890A EP80301890A EP0021671A1 EP 0021671 A1 EP0021671 A1 EP 0021671A1 EP 80301890 A EP80301890 A EP 80301890A EP 80301890 A EP80301890 A EP 80301890A EP 0021671 A1 EP0021671 A1 EP 0021671A1
Authority
EP
European Patent Office
Prior art keywords
light
smoke
smoke detector
detector according
detecting means
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.)
Withdrawn
Application number
EP80301890A
Other languages
German (de)
English (en)
Inventor
Makoto Hanyu
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.)
Secom Co Ltd
Original Assignee
Secom Co 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
Priority claimed from JP7626179A external-priority patent/JPS562092A/ja
Priority claimed from JP1197280A external-priority patent/JPS561339A/ja
Application filed by Secom Co Ltd filed Critical Secom Co Ltd
Publication of EP0021671A1 publication Critical patent/EP0021671A1/fr
Withdrawn legal-status Critical Current

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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 present invention relates to a highly sensitive device for achieving quick detection of smoke which is produced when a fire breaks out, and more particularly relates to an improvement in a smoke detector of the type in which the detection of smoke is carried out through the detection of light scattered by particles of smoke.
  • the conventional smoke detector when the conventional smoke detector is arranged at a place where the smoke detection should be carried out, the surrounding light can be so strong that the intensity of the light is several hundreds luxes. Furhter, when the smoke detector is directly exposed to the sun light, the intensity of the surrounding light is high, up to several ten thousands luxes. Therefore, the conventional smoke detector has, inside thereof, a very complicated dark chamber to permit entrance of air into the chamber, but not to permit entrance of the surrounding light.
  • the Japanese laid-open utility model application No. 54(1979)-29078 or No. 54(1979)-12390 discloses such a complicated dark chamber to be provided for the conventional smoke detector. As a result, the physical structure of the conventional smoke detector is very complex, and the size of the detector must be large.
  • the manufacturing cost of the detector is high.
  • the complicated dark chamber of the conventional smoke detector usually makes it difficult to permit the entrance of slowly moving smoke into the chamber, the conventional smoke detector often fails to achieve reliable detection of smoke which is produced during the initial stage of a fire.
  • Another object of the present invention is to provide a highly sensitive smoke detector capable of achieving quick detection of smoke which is produced during the initial stage of a fire.
  • a further object of the present invention is to provide a smoke detector having not only a dark chamber of a simple structure, but also a high signal to noise ratio (S/N ratio) which is defined as a ratio of the outputs of the detector in the case where the entrance of smoke to be detected into the detector takes place and in the case where no entrance of smoke into the detector takes place.
  • S/N ratio signal to noise ratio
  • an optical unit 1 incorporates therein a light emitting portion 2 and a light receiving or detecting portion 3-of a smoke detector according to an embodiment of the present invention.
  • the optical unit 1 is mounted on a-base plate 4.
  • the light emitting portion 2 of the optical unit 1 is provided with a beam source 5 for emitting a beam of light, a spacer member 10a for supporting the beam source 5 and for determining an angle of emission of the beam of light, and a light pervious sphere element 6a.
  • the beam source 5 may be, for example, a light emitting diode, usually referred to as an LED element.
  • An outlet opening 7a having a diameter slightly smaller than the diameter of the sphere element 6a, is formed in an end face of the light emitting portion 2.
  • the light emitting portion 2 emits a beam of light through the outlet opening 7a toward the outside of the light emitting portion 2.
  • a flange piece 8 extends from a part of the periphery of the outlet opening 7a toward the outside of the opening 7a.
  • the flange piece 8 is provided for preventing the beam of light emitted by the beam source 5 from directly entering into the light detecting portion 3.
  • the beam source 5 of the light emitting portion 2 is generally comprised of a semi conductor light source, such as the above-mentioned LED.
  • many other light sources such as a visible light radiation element, an infrared rays radiation element, an ultraviolet rays radiation element and a white light emitting lamp may also be employed, as required.
  • the light detecting portion 3 is arranged adjacent to and at a right angle with the light emitting portion 2, via a space into which the beam of light is emitted from the light emitting portion 2.
  • the light detecting portion 3 is formed with a light inlet opening 7b, and is provided with a light pervious sphere element 6b having a diameter slightly larger than that of the light inlet opening 7b, a spacer member 10b, and a light sensitive element, such as a photo-electric element 9.
  • the spacer member 10b supports the sphere element 6b and has an opening through which a light, having been scattered from particles of smoke entering into the above-mentioned space, passes at a predetermined converging angle toward the light receiving surface of the photo-electric element 9.
  • the beam of light emitted from the beam source 5 passes through the spacer member 10a, the sphere element 6a and the light outlet opening 7a of the light emitting portion 2, and is thrown on smoke which enters into the smoke detector.
  • the beam of light is scattered from particles of the smoke.
  • the scattered light then enters into the light detecting portion 3 through the inlet opening-7b.
  • the detection of the smoke is carried out through the detection of the scattered light.
  • the light pervous sphere elements 6a and 6b are sphere bodies, respectively, made of a plastic material or glass.
  • the spherical shape of the light pervious sphere element 6a is very advantageous for assembling the light emitting portion 2, since it is very easy to align the central axis of the beam source with the optical axis of the sphere element 6a. Further, since the light pervious sphere elements 6a and 6b can be used, as an optical element having a small optical caliber and a short focal distance, the optical unit 1 incorporating therein the light emitting portion 2 and the light detecting portion 3 can be a very close assembly. Therefore, it is possible not only to acquire strong scattered light from introducing smoke into a space adjacent to the light outlet opening 7a of the light emitting portion 2, but also to direct the strong scattered light into the light detecting portion 3. As a result, even if the smoke is thin, it is ensured that the detection of the smoke is accurate and reliable.
  • the above-mentioned optical unit 1 mounted on the base plate 4 is housed in a housing 13 and a top covering 11 attached to the top of the housing 13.
  • the top covering 11 prevents the surrounding light from entering into a dark chamber which is formed inside the top covering 11.
  • the smoke detector can be a highly sensitive smoke detecting device.
  • the pair of light blocking plates 12a arranged on opposite sides of the optical unit 1 are effective for preventing the surrounding light or sun beams from directly entering into the dark chamber through the large smoke entrance bores lla formed in the top covering 11.
  • the light blocking plate 12b is effective for preventing the surrounding light from directly entering into the dark chamber through a small smoke entrance bore llb formed in the top covering 11.
  • the light blocking plate 12b is also effective for preventing the beam of light emitted from the light emitting portion 2 from entering into the light detecting portion 3 after the beam of light have been reflected from an inner surface of the top covering 11. That is, the plate 12b absorbs the beam of light reflected from the inner surface of the top covering 11.
  • the smoke detector is provided with a conventional electric amplifier 14 electrically connected to the photo-electric element 9.
  • the amplifier 14 amplifies electrical smoke detection signals coming from the photo-electric element 9 of the light detecting portion 2.
  • the amplified signal is then used for actuating alarm devices (not shown) or-fire extinguishing devices (not shwon).
  • the beam source 5 of the light emi-tting portion 2 emits a beam of light having wave lengths except for wave lengths of visible lights. That is, the beam source 5 emits infrared rays or ultraviolet rays.
  • the beam source 5 may be comprised of an infrared light emitting diode (LED) which emits infrared rays having a peak wave length of 9400 A. Therefore, the light detecting portion 3 employs a light selecting element which permits passage therethrough of only the above-mentioned infrared rays.
  • a filter member 15 As one typical example of the light selecting element, a filter member 15 (Fig.
  • the photo-electric element 9 per se used as a light sensitive element may be comprised of a certain selected photo-electric element responsive to light having a preselected wave length.
  • the light pervious sphere element 6b may be made of material which has the same filtering effect as the above-mentioned filter member 15.
  • the filter member 15 may be arranged between the photo-electric element 9 and the light pervious sphere element 6b.
  • the infrared rays When the infrared rays are emitted from the beam source 5 of the light emitting portion 2, the infrared rays are scattered by smoke entering into the dark chamber of the smoke detector. Then, with the scattered infrared rays, the ray components having wave lengths of 9200 A or more are permitted to enter into the light detecting portion 3 through the filter member 15. Therefore, the light detecting portion 3 is not affected by visible light, including the surrounding light of the detector. As a result, S/N ratio of the smoke detector can be very high. Consequently, the smoke detector can have a high smoke detection performance without erroneous operation. Further, since the structure of the dark chamber formed inside the top covering 11 is very simple, smoke is able to easily enter into the dark chamber. Therefore, quick detection of smoke is ensured by the smoke detector of the present invention. At this stage, it should be noted that in the case where invisible light, such as infrared rays or ultraviolet rays are employed, the top covering 11 may be eliminated.

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)
  • Investigating Or Analysing Materials By Optical Means (AREA)
EP80301890A 1979-06-19 1980-06-06 Détecteur de fumée Withdrawn EP0021671A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP7626179A JPS562092A (en) 1979-06-19 1979-06-19 Smoke sensor
JP76261/79 1979-06-19
JP1197280A JPS561339A (en) 1980-02-05 1980-02-05 Improved scattered-light type smoke sensor
JP11972/80 1980-02-05

Publications (1)

Publication Number Publication Date
EP0021671A1 true EP0021671A1 (fr) 1981-01-07

Family

ID=26347500

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80301890A Withdrawn EP0021671A1 (fr) 1979-06-19 1980-06-06 Détecteur de fumée

Country Status (3)

Country Link
EP (1) EP0021671A1 (fr)
AU (1) AU5912080A (fr)
DK (1) DK237780A (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2533653B2 (ja) * 1989-09-26 1996-09-11 松下電工株式会社 光電式煙感知器

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2141655A1 (fr) * 1971-06-03 1973-01-26 Electro Signal Lab
US3882477A (en) * 1973-03-26 1975-05-06 Peter H Mueller Smoke and heat detector incorporating an improved smoke chamber
US3916209A (en) * 1973-07-24 1975-10-28 Electro Signal Lab Vaned baffle for optical smoke detector
US4129383A (en) * 1976-02-10 1978-12-12 Chloride Incorporated Smoke detector and housing assembly therefore

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2141655A1 (fr) * 1971-06-03 1973-01-26 Electro Signal Lab
US3882477A (en) * 1973-03-26 1975-05-06 Peter H Mueller Smoke and heat detector incorporating an improved smoke chamber
US3916209A (en) * 1973-07-24 1975-10-28 Electro Signal Lab Vaned baffle for optical smoke detector
US4129383A (en) * 1976-02-10 1978-12-12 Chloride Incorporated Smoke detector and housing assembly therefore

Also Published As

Publication number Publication date
AU5912080A (en) 1981-01-08
DK237780A (da) 1980-12-20

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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

Designated state(s): CH DE FR GB NL SE

17P Request for examination filed

Effective date: 19810606

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

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19830121

RIN1 Information on inventor provided before grant (corrected)

Inventor name: HANYU, MAKOTO