EP0111012A1 - Detecteur de fumee du type a ionisation - Google Patents

Detecteur de fumee du type a ionisation Download PDF

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Publication number
EP0111012A1
EP0111012A1 EP83901734A EP83901734A EP0111012A1 EP 0111012 A1 EP0111012 A1 EP 0111012A1 EP 83901734 A EP83901734 A EP 83901734A EP 83901734 A EP83901734 A EP 83901734A EP 0111012 A1 EP0111012 A1 EP 0111012A1
Authority
EP
European Patent Office
Prior art keywords
electrode
smoke
ionization
source
radioactive source
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
EP83901734A
Other languages
German (de)
English (en)
Other versions
EP0111012A4 (fr
EP0111012B1 (fr
Inventor
Toru Nohmi Bosai Kogyo Co. Ltd. Sasaki
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.)
Nohmi Bosai Ltd
Original Assignee
Nohmi Bosai Kogyo 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
Application filed by Nohmi Bosai Kogyo Co Ltd filed Critical Nohmi Bosai Kogyo Co Ltd
Publication of EP0111012A1 publication Critical patent/EP0111012A1/fr
Publication of EP0111012A4 publication Critical patent/EP0111012A4/fr
Application granted granted Critical
Publication of EP0111012B1 publication Critical patent/EP0111012B1/fr
Expired legal-status Critical Current

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Classifications

    • 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 present invention relates to a single radioactive source ionization smoke detector.
  • the previously known jonization smoke detectors can be divided into two categories: 1) in the smoke detector with two radioactive sources and an outer measurement jonification chamber that is freely accessible to the smoke, as well as an inner comparison or reference jonification chamber that is not accessible to the smoke, whereby each chamber has a radioactive source, and 2) in smoke detectors with a single radioactive source and an intermediate electrode dividing the two jonification chambers, which contains a small passage or opening, for the irradiation of the outer jonification chamber by the radioactive source arranged in the inner jonification chamber.
  • the smoke detector with a radioactive source has advantages over the two-source smoke detector because of its simple construction and its lower radiation energy requirement.
  • operational tests of the single-source smoke detector have shown disadvantages that lie in its construction.
  • the smoke has great difficulty in getting through the small passage into the inner ionization chamber. Once the smoke has entered the outer ionization chamber, it is difficult to remove it, which prevents the smoke detector from returning quickly to its initial or normal state.
  • the Oeff voltage or the passage in the intermediate electrode is increased and the ionization current flowing in the inner ionization chamber is kept in its saturation range.
  • the resistance of the inner ionization chamber remains stable and is independent of the smoke flow.
  • the radioactive source in the inner ionization chamber is always exposed to the atmosphere and thus to pollution, so that the ionization current changes. This leads to incorrect operation and false alarms.
  • the object of the invention is to provide a ionization smoke detector with a single radioactive source, in which this contamination of the source is eliminated and the smoke is quickly dispersed after the operational test has been completed. This quickly brings the smoke detector into its initial or normal state.
  • FIGS. 1 and 2 show an exemplary embodiment.
  • An annular wall 2 is provided on the substrate 1.
  • a radioactive source 3 is arranged on an electrode 5, the vertical position of which can be adjusted by means of a screw 4.
  • a disk-shaped inner electrode 6 is provided with a disk-like intermediate electrode 8 carried by several webs 9, in the middle of which an opening 10 is provided.
  • One. grid-shaped outer electrode 11 is attached to the substrate and surrounds the electrodes 6 and 8.
  • the inner ionization chamber a is formed by the inner electrode 6 and the intermediate electrode 8.
  • the outer ionization chamber b is delimited by the intermediate electrode 8 and the outer electrode 11.
  • the radioactive source 3 sends its radiation into the ionization chambers a, b through the. Openings 7, 10, which are coaxial to the source 3. This is the jonider
  • the inner electrode 6 is electrically connected to the positive terminal p and the outer electrode 11 to the negative terminal n of the detector.
  • the intermediate electrode 8 is connected to the gate electrode of an FET located between the terminals p, n and via a resistor R.
  • the electrode 5 is connected to the tap of a variable resistor VR, which lies between the terminals p and n.
  • the source electrode of the FET is located on a switching circuit SW, which is connected between the terminals p and n.
  • the inner ionization chamber a has such a voltage that the ionization current flowing into it lies in the saturation range.
  • the operation of the smoke detector is described below.
  • the dust-carrying air moves evenly into the jonification chambers a, b and again out of the jonification chambers, in accordance with the air flow prevailing in the room in which the smoke detector is installed.
  • This is made possible because the intermediate electrode 8 is only supported by a plurality of webs 9. Because the inner electrode 6 and the annular wall 2 cover the radioactive source 3, the source is protected from the air flow and remains in a clean state despite the opening 7 in the inner electrode 6.
  • the ionization current flowing in the outer ionization chamber b is reduced. This increases the gate potential of the FET that operates the fire alarm display circuit SW when it reaches a predetermined voltage.
  • a smoke generator supplies the necessary smoke to test the smoke detector. If the smoke generator is removed from the detector at the end of the test process, the smoke present in the ionization chambers a and b is quickly removed. The This rapid removal of the smoke takes place through the air circulation in the room, because the two ionization chambers are freely accessible to the air. The smoke detector is quickly returned to its normal working state at the end of the test.
  • the potential of the intermediate electrode 8 is changed accordingly, so that the sensitivity of the smoke detector can be adjusted.
  • the radioactive source can be adequately protected against contamination.
  • the smoke detector is quickly cleared of any smoke after the end of an operational test and is therefore returned to its initial or normal state within a short time.
  • This single radioactive jonization smoke detector has several advantages over the prior art.
  • Figure 1 shows a Jonisation smoke detector in cross section and Figure 2 shows the electrical circuit for this detector.
  • the inner ionization chamber a the outer ionization chamber b, substrate 1, annular wall 2, radioactive source 3, inner electrode 6, openings 7, 10, intermediate electrode 8, and the outer electrode 11 are shown.

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)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)

Abstract

Détecteur de fumée du type à ionisation pour une alarme d'incendie, et plus particulièrement détecteur de fumée du type à ionisation dans lequel une chambre interne d'ions (a) consiste en une électrode interne (6) et en une électrode intermédiaire (8), et une chambre externe d'ions (b) consiste en cette électrode intermédiaire (8) et en une électrode externe (11), ces chambres (a, b) ionisant l'air à l'intérieur d'elles par une source de radiation (3). Dans le détecteur de fumée à ionisation de ce type selon l'invention, la source de radiation est difficile à contaminer. Lorsque la fumée est effectivement appliquée pendant un test de fonctionnement, afin que la fumée puisse se diffuser immédiatement après le test et que le fonctionnement reprenne sans problème, la source (3) est entourée par l'électrode interne (6), un substrat (1), et une paroi annulaire (2), l'électrode intermédiaire (8) est supportée par une pluralité de montants (9) s'étendant depuis le substrat (1), et des trous (7, 10) sont percés dans les électrodes (6 et 8) de sorte que la radiation provenant de la source (3) est émise au travers des trous (7, 10) vers les chambres (a, b).
EP83901734A 1982-06-07 1983-06-07 Detecteur de fumee du type a ionisation Expired EP0111012B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP1982083510U JPS58186463U (ja) 1982-06-07 1982-06-07 イオン化式煙感知器
JP83510/82U 1982-06-07

Publications (3)

Publication Number Publication Date
EP0111012A1 true EP0111012A1 (fr) 1984-06-20
EP0111012A4 EP0111012A4 (fr) 1984-12-11
EP0111012B1 EP0111012B1 (fr) 1989-08-09

Family

ID=13804477

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83901734A Expired EP0111012B1 (fr) 1982-06-07 1983-06-07 Detecteur de fumee du type a ionisation

Country Status (5)

Country Link
US (1) US4594512A (fr)
EP (1) EP0111012B1 (fr)
JP (1) JPS58186463U (fr)
DE (1) DE3380374D1 (fr)
WO (1) WO1983004449A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2594953A1 (fr) * 1986-02-25 1987-08-28 Lewiner Jacques Detecteur de fumee a chambre d'ionisation
EP0217100A3 (en) * 1985-08-24 1988-02-10 Nohmi Bosai Kogyo Co., Ltd. An ionization-type smoke detector

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6044194U (ja) * 1983-09-05 1985-03-28 能美防災工業株式会社 イオン化式煙感知器の耐熱ケ−ス
CA1267735A (fr) * 1986-01-17 1990-04-10 Nohmi Bosai Kogyo Co., Ltd. Detecteur de fumee, du type a ionisation
DE3921377A1 (de) * 1989-06-29 1991-01-03 Inotech Ag Wohlen Vorrichtung und verfahren zum messen von elektronen
US5485144A (en) * 1993-05-07 1996-01-16 Pittway Corporation Compensated ionization sensor
US20030180591A1 (en) * 2001-03-29 2003-09-25 Steven Danyluk Contact potential difference ionization battery

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1280304A (en) * 1968-09-26 1972-07-05 Hochiki Co A smoke sensing detector for smoke sensing apparatus
USRE30323E (en) * 1968-09-26 1980-07-01 Hochiki Kabushiki Kaisha Smoke detector adapted to a smoke sensing apparatus
CA1116319A (fr) * 1977-11-18 1982-01-12 Jack Bryant Detecteurs de fumee
GB2013393B (en) * 1977-11-18 1982-03-03 Radiochemical Centre Ltd Smoke detectors
CA1115860A (fr) * 1977-11-18 1982-01-05 Dennis W.S. Smout Detecteurs de fumee
GB2010578B (en) * 1977-11-18 1982-09-15 Radiochemical Centre Ltd Smoke detectors
JPS5821031Y2 (ja) * 1978-03-15 1983-05-02 ホーチキ株式会社 煙感知器
JPS5759965Y2 (fr) * 1978-04-25 1982-12-21

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0217100A3 (en) * 1985-08-24 1988-02-10 Nohmi Bosai Kogyo Co., Ltd. An ionization-type smoke detector
FR2594953A1 (fr) * 1986-02-25 1987-08-28 Lewiner Jacques Detecteur de fumee a chambre d'ionisation
EP0236223A1 (fr) * 1986-02-25 1987-09-09 Jacques Lewiner Détecteur de fumée à chambre d'ionisation

Also Published As

Publication number Publication date
EP0111012A4 (fr) 1984-12-11
JPS58186463U (ja) 1983-12-10
US4594512A (en) 1986-06-10
EP0111012B1 (fr) 1989-08-09
WO1983004449A1 (fr) 1983-12-22
DE3380374D1 (en) 1989-09-14
JPH029430Y2 (fr) 1990-03-08

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