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 signalsInfo
- 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
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.
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) |
-
1973
- 1973-09-05 FR FR7332686A patent/FR2242736A1/en active Granted
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 |