EP0111012B1 - Rauchsensor des ionisationstyps - Google Patents

Rauchsensor des ionisationstyps Download PDF

Info

Publication number
EP0111012B1
EP0111012B1 EP83901734A EP83901734A EP0111012B1 EP 0111012 B1 EP0111012 B1 EP 0111012B1 EP 83901734 A EP83901734 A EP 83901734A EP 83901734 A EP83901734 A EP 83901734A EP 0111012 B1 EP0111012 B1 EP 0111012B1
Authority
EP
European Patent Office
Prior art keywords
ionization
electrode
smoke
radioactive source
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.)
Expired
Application number
EP83901734A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0111012A1 (de
EP0111012A4 (de
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/de
Publication of EP0111012A4 publication Critical patent/EP0111012A4/de
Application granted granted Critical
Publication of EP0111012B1 publication Critical patent/EP0111012B1/de
Expired 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
    • G08B17/11—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 an ionization smoke detector with a single radioactive source according to the preamble of claim 1.
  • the ionization smoke detectors known to date can be divided into two categories: 1) smoke detectors with two radioactive sources and an outer measurement ionization chamber that is freely accessible to the smoke, and an inner comparison or reference ionization 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 which divides the two ionization chambers and which has a small passage. Opening contains for the irradiation of the outer ionization chamber by the radioactive source arranged in the inner ionization 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.
  • GB-A-2 013 393 describes such a smoke detector with a radioactive source for both ionization chambers.
  • the radioactive source is arranged in the inner ionization chamber and is exposed to contamination by the smoke particles entering the inner ionization chamber.
  • a cover plate was placed over it, which has an opening for the desired passage of the radioactive radiation for ionizing the inner and outer ionization chamber.
  • the size of the opening is a compromise between the desired ionization of the two chambers and the undesirable contamination of the radioactive source and can never be optimal. Either ionization and pollution are large or small at the same time. In no case is the ionization large and the pollution small. This did not solve the problem of preventing pollution.
  • US-A-3935466 shows a smoke detector with a radioactive source for both ionization chambers.
  • the radioactive source can be located within the inner or outer ionization chamber.
  • the size of the opening required for the passage of the ionization rays into both chambers is only dependent on the desired amount of the rays, since the influence of the contamination of the radioactive source on the sensitivity was not known.
  • the object of the invention is to provide an 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 back to its initial or normal state.
  • FIGS. 1 and 2 show an exemplary embodiment.
  • Figure 1 shows an ionization 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.
  • 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 disc-shaped inner electrode 6 is arranged on the annular wall 2.
  • a disc-like intermediate electrode 8 is provided which is supported by a plurality of webs 9 and in the middle of which an opening 10 is provided.
  • a 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 chamber a, b, specifically through the openings 7, 10, which are coaxial with the source 3. As a result, the air is ionized in the two chambers a and b.
  • 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 at the tap of a change union resistor VR connected between terminals p and n.
  • the source electrode of the FET is on a 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 in it is in the saturation range.
  • the operation of the smoke detector is described below.
  • the dust-carrying air moves evenly into the ionization chambers a, b and out of the ionization chambers again, depending on 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 decreases. 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 ionization chambers a and b is quickly removed. 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 satisfactorily 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-source ionization smoke detector has several advantages over the prior art.

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)
EP83901734A 1982-06-07 1983-06-07 Rauchsensor des ionisationstyps Expired EP0111012B1 (de)

Applications Claiming Priority (2)

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

Publications (3)

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

Family

ID=13804477

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83901734A Expired EP0111012B1 (de) 1982-06-07 1983-06-07 Rauchsensor des ionisationstyps

Country Status (5)

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

Families Citing this family (7)

* 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
US4761557A (en) * 1985-08-24 1988-08-02 Kohmi Bosai Kogyo Co., Ltd. Ionization-type smoke detector
CA1267735A (en) * 1986-01-17 1990-04-10 Nohmi Bosai Kogyo Co., Ltd. Ionization type-smoke detector
FR2594953B1 (fr) * 1986-02-25 1989-05-05 Lewiner Jacques Detecteur de fumee a chambre d'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
USRE30323E (en) * 1968-09-26 1980-07-01 Hochiki Kabushiki Kaisha Smoke detector adapted to a smoke sensing apparatus
GB1280304A (en) * 1968-09-26 1972-07-05 Hochiki Co A smoke sensing detector for smoke sensing apparatus
CA1116319A (en) * 1977-11-18 1982-01-12 Jack Bryant Smoke detectors
GB2010578B (en) * 1977-11-18 1982-09-15 Radiochemical Centre Ltd Smoke detectors
CA1115860A (en) * 1977-11-18 1982-01-05 Dennis W.S. Smout Smoke detectors
GB2013393B (en) * 1977-11-18 1982-03-03 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 (enExample) * 1978-04-25 1982-12-21

Also Published As

Publication number Publication date
EP0111012A1 (de) 1984-06-20
JPS58186463U (ja) 1983-12-10
EP0111012A4 (de) 1984-12-11
US4594512A (en) 1986-06-10
DE3380374D1 (en) 1989-09-14
WO1983004449A1 (fr) 1983-12-22
JPH029430Y2 (enExample) 1990-03-08

Similar Documents

Publication Publication Date Title
DE2652970C3 (de) Ionisations-Brandmelder
EP0127645B1 (de) Brandmelder und dafür bestimmte elektrodenanordnung
DE2023954C3 (de) Ionisationsfeuermelder
DE1648902B2 (de) Ionenkammerdetektor
DE2415479A1 (de) Ionisationsfeuermelder
EP0111012B1 (de) Rauchsensor des ionisationstyps
DE2738918C3 (de) Ionisationskammer mit zwei Meßkammern
DE2603373A1 (de) Ionisationsdetektor
EP0178431B1 (de) Gegenfeld-Spektrometer für die Elektronenstrahl-Messtechnik
DE2415559A1 (de) Anzeigevorrichtung fuer den zustand eines nichtleitenden fliessfaehigen mediums
DE1928874B2 (de) Ionisationsfeuermelder
DE4320607C2 (de) Anordnung zur Spurengasanalyse
EP0030621B1 (de) Ionisationsrauchmelder mit erhöhter Betriebssicherheit
DE2364034C3 (de) Überspannungsableiter
DE8337787U1 (de) Jonisation-rauchmelder
DE2546970C3 (de) Ionisations-Rauchmelder
DE2604672C2 (de) Vorrichtung zur Kontrolle der Homogenität der radialen Intensitätsverteilung eines ionisierenden Strahlungsbündels
DE1616020B2 (de) Feuermeldevorrichtung
DE2631241B2 (de) Rauchdetektor
DE1014759B (de) Gasdruckmessvorrichtung
DE4016231C2 (de) Ionisations-Rauchdetektor
CH572644A5 (en) Ionisation chamber fire detector - with threshold cct. monitoring ionisation current connected to switch cct. for further chamber
DE1101370B (de) Einrichtung zur elektrischen Beladung von in einem Luftstrom suspendierten Partikeln mittels radioaktiver Praeparate
DE3010739C2 (de) Flüssigkeitsstandfühler
DE2711457C2 (de) Ionisationsbrandmelder

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): BE CH DE FR GB LI

17P Request for examination filed

Effective date: 19840124

17Q First examination report despatched

Effective date: 19870909

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): BE CH DE FR GB LI

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

Ref country code: BE

Effective date: 19890809

REF Corresponds to:

Ref document number: 3380374

Country of ref document: DE

Date of ref document: 19890914

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
ET Fr: translation filed
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
REG Reference to a national code

Ref country code: CH

Ref legal event code: PFA

Free format text: NOHMI BOSAI LTD

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

Ref country code: FR

Payment date: 19950510

Year of fee payment: 13

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

Ref country code: GB

Payment date: 19950512

Year of fee payment: 13

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

Ref country code: DE

Payment date: 19950529

Year of fee payment: 13

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

Ref country code: GB

Effective date: 19960607

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

Ref country code: CH

Payment date: 19960826

Year of fee payment: 14

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

Effective date: 19960607

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

Ref country code: FR

Effective date: 19970228

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

Ref country code: DE

Effective date: 19970301

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

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: 19970630

Ref country code: CH

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

Effective date: 19970630

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL