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GB1299234A - Ionization smoke detector - Google Patents

Ionization smoke detector

Info

Publication number
GB1299234A
GB1299234A GB5283870A GB5283870A GB1299234A GB 1299234 A GB1299234 A GB 1299234A GB 5283870 A GB5283870 A GB 5283870A GB 5283870 A GB5283870 A GB 5283870A GB 1299234 A GB1299234 A GB 1299234A
Authority
GB
United Kingdom
Prior art keywords
electrode
ionization
chambers
electrodes
smoke detector
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
GB5283870A
Inventor
Akihiro Kobayashi
Koju 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.)
Nittan Co Ltd
Original Assignee
Nittan 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 Nittan Co Ltd filed Critical Nittan Co Ltd
Priority to GB5283870A priority Critical patent/GB1299234A/en
Publication of GB1299234A publication Critical patent/GB1299234A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
    • G01N27/64—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode using wave or particle radiation to ionise a gas, e.g. in an ionisation chamber
    • 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
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J41/00—Discharge tubes for measuring pressure of introduced gas or for detecting presence of gas; Discharge tubes for evacuation by diffusion of ions
    • H01J41/02—Discharge tubes for measuring pressure of introduced gas or for detecting presence of gas
    • H01J41/08—Discharge tubes for measuring pressure of introduced gas or for detecting presence of gas with ionisation by means of radioactive substances, e.g. alphatrons

Landscapes

  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Toxicology (AREA)
  • Electrochemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
  • Fire-Detection Mechanisms (AREA)

Abstract

1299234 Analyzing gases NITTAN CO Ltd 6 Nov 1970 52838/70 Heading G1N [Also in Divisions H1 and H3] An ionization smoke detector comprises three electrodes 2, 3, 5 which form outer and inner ionization chambers 8 and 9 respectively such that air can pass into both chambers, and a single radio-active source 7 which irradiates both electrodes. An FET device 11 embedded in insulator disc 1 has its gate electrode connected to the intermediate electrode 3, emitter to the outer electrode 2 and collector to the inner electrode 5. A battery is connected between points A and B and the point C is connected by a Zener diode 15 to the control electrode of a Sicontrolled rectifier 16. When smoke enters the ionization chambers the potentional of the intermediate electrode 3 changes causing an increase of current through the FET device 11 until the voltage of the emitter exceeds the Zener voltage of diode 15 when the Si-controlled rectifier 16 is driven into conduction thereby energizing a relay 18 which triggers an alarm device 19.
GB5283870A 1970-11-06 1970-11-06 Ionization smoke detector Expired GB1299234A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB5283870A GB1299234A (en) 1970-11-06 1970-11-06 Ionization smoke detector

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5283870A GB1299234A (en) 1970-11-06 1970-11-06 Ionization smoke detector

Publications (1)

Publication Number Publication Date
GB1299234A true GB1299234A (en) 1972-12-13

Family

ID=10465532

Family Applications (1)

Application Number Title Priority Date Filing Date
GB5283870A Expired GB1299234A (en) 1970-11-06 1970-11-06 Ionization smoke detector

Country Status (1)

Country Link
GB (1) GB1299234A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4012729A (en) * 1975-06-19 1977-03-15 Statitrol Corporation Multi-element ionization chamber
FR2438841A1 (en) * 1978-10-13 1980-05-09 Commissariat Energie Atomique Ionic fire detection sensor - contains auxiliary electrode and applies intermediate voltage to ionised chamber screen
GB2182198A (en) * 1985-10-31 1987-05-07 Gent Ltd Ionisation detection chamber
US4740703A (en) * 1983-09-05 1988-04-26 Nohmi Bosai Kogyo Kabushiki Kaisha Ionization-type smoke detector
GB2202369A (en) * 1987-02-06 1988-09-21 Kernforschungsz Karlsruhe Radioactive-gas detection apparatus comprising an ionization chamber
US4924098A (en) * 1987-11-30 1990-05-08 Radiation Detectors, Inc. Nuclear radiation level detector

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4012729A (en) * 1975-06-19 1977-03-15 Statitrol Corporation Multi-element ionization chamber
FR2438841A1 (en) * 1978-10-13 1980-05-09 Commissariat Energie Atomique Ionic fire detection sensor - contains auxiliary electrode and applies intermediate voltage to ionised chamber screen
US4740703A (en) * 1983-09-05 1988-04-26 Nohmi Bosai Kogyo Kabushiki Kaisha Ionization-type smoke detector
GB2182198A (en) * 1985-10-31 1987-05-07 Gent Ltd Ionisation detection chamber
GB2182198B (en) * 1985-10-31 1991-05-15 Gent Ltd Ionisation detection chamber
GB2202369A (en) * 1987-02-06 1988-09-21 Kernforschungsz Karlsruhe Radioactive-gas detection apparatus comprising an ionization chamber
US4924098A (en) * 1987-11-30 1990-05-08 Radiation Detectors, Inc. Nuclear radiation level detector

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Legal Events

Date Code Title Description
PS Patent sealed
48R Reference inserted (sect. 8/1949)
429A Application made for amendment of specification (sect. 29/1949)
429H Application (made) for amendment of specification now open to opposition (sect. 29/1949)
429D Case decided by the comptroller ** specification amended (sect. 29/1949)
SPA Amended specification published
PCNP Patent ceased through non-payment of renewal fee