FR2242736A1 - Ionisation chamber fire detector - discharge current is converted to digital pulse rate compared with fixed signals - Google Patents

Ionisation chamber fire detector - discharge current is converted to digital pulse rate compared with fixed signals

Info

Publication number
FR2242736A1
FR2242736A1 FR7332686A FR7332686A FR2242736A1 FR 2242736 A1 FR2242736 A1 FR 2242736A1 FR 7332686 A FR7332686 A FR 7332686A FR 7332686 A FR7332686 A FR 7332686A FR 2242736 A1 FR2242736 A1 FR 2242736A1
Authority
FR
France
Prior art keywords
pulse rate
converted
discharge current
fet
fire 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.)
Granted
Application number
FR7332686A
Other languages
French (fr)
Other versions
FR2242736B1 (en
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.)
Total Foerstner and Co
Original Assignee
Total Foerstner and Co
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 Total Foerstner and Co filed Critical Total Foerstner and Co
Priority to FR7332686A priority Critical patent/FR2242736A1/en
Publication of FR2242736A1 publication Critical patent/FR2242736A1/en
Application granted granted Critical
Publication of FR2242736B1 publication Critical patent/FR2242736B1/fr
Granted legal-status Critical Current

Links

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

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)

Abstract

The detector provides a direct indication on the smoke concentration without the aid of additional instruments, and is also readily calibrated. The deviation in the ionization chamber pulse rate from the set level formed by signal of a generator provides a trip for the warning system. The analog-digital conversion can be provided by a threshold switch whose pulse charges a capacitor, the new cycle initiated by the discharge of the latter. The ionization chamber includes a radioactive element and is inseries with a capacitor while the gate-source junction of a FET forms the impedance converter. The FET controls the threshold switch of a transistor which discharges the capacitor via the gate-source junction of the FET.
FR7332686A 1973-09-05 1973-09-05 Ionisation chamber fire detector - discharge current is converted to digital pulse rate compared with fixed signals Granted FR2242736A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR7332686A FR2242736A1 (en) 1973-09-05 1973-09-05 Ionisation chamber fire detector - discharge current is converted to digital pulse rate compared with fixed signals

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7332686A FR2242736A1 (en) 1973-09-05 1973-09-05 Ionisation chamber fire detector - discharge current is converted to digital pulse rate compared with fixed signals

Publications (2)

Publication Number Publication Date
FR2242736A1 true FR2242736A1 (en) 1975-03-28
FR2242736B1 FR2242736B1 (en) 1977-02-25

Family

ID=9124881

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7332686A Granted FR2242736A1 (en) 1973-09-05 1973-09-05 Ionisation chamber fire detector - discharge current is converted to digital pulse rate compared with fixed signals

Country Status (1)

Country Link
FR (1) FR2242736A1 (en)

Also Published As

Publication number Publication date
FR2242736B1 (en) 1977-02-25

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Legal Events

Date Code Title Description
TP Transmission of property
ST Notification of lapse
AR Application made for restoration
BR Restoration of rights