GB1499581A - Fire detector - Google Patents
Fire detectorInfo
- Publication number
- GB1499581A GB1499581A GB17175A GB17175A GB1499581A GB 1499581 A GB1499581 A GB 1499581A GB 17175 A GB17175 A GB 17175A GB 17175 A GB17175 A GB 17175A GB 1499581 A GB1499581 A GB 1499581A
- Authority
- GB
- United Kingdom
- Prior art keywords
- transistor
- voltage
- conductive
- horn
- potentiometer
- 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
Links
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
- G08B29/18—Prevention or correction of operating errors
- G08B29/181—Prevention or correction of operating errors due to failing power supply
-
- 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
- G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
- G08B29/02—Monitoring continuously signalling or alarm systems
- G08B29/04—Monitoring of the detection circuits
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Computer Security & Cryptography (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Fire-Detection Mechanisms (AREA)
- Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
- Fire Alarms (AREA)
- Alarm Systems (AREA)
Abstract
1499581 Ionization alarm systems PITTWAY CORP 3 Jan 1975 [7 Jan 1974] 171/75 Heading G1N [Also in Division G4] A fire alarm monitoring system employing an ionization chamber 34 and a source of alpha particles 40 is energized from a 12v supply and comprises, a L.E.D. indicator 80 which is illuminated when the system is working in a proper state of readiness, and an alarm horn 68. In the event of a fire the products of combustion increase the impedance of the chamber 34 which causes the conductivity of a MOS-FET transistor amplifer 46 to increase, thereby lowering the voltage at the junction of the resistors 50, 52, and at the base of transistor 54. When this signal or junction voltage, which is the voltage from the MOS-FET amplifier drops below the reference voltage at the base of the transistor 56 forming part of a differential amplifier or voltage comparator, the transistor 56 will be rendered non-conductive and the transistor 54 will be rendered conductive to forwardly bias the transistor 66 and energize the horn 68. The system may be adjusted for sensitivity by altering the potentiometer 64. Should the line voltage at 42 fail, then the voltage across the transistor 54 and the voltage across the diode 59 is no longer sufficient to hold the transistor 72 which then turns off, becomes non-conductive and extinguishes the L.E.D. 80. Should the potentiometer 64 be improperly adjusted to provide too high a voltage then the transistor 54 would be rendered conductive to sound the horn 68. If the potentiometer 64 provides too low a voltage the horn would not sound but the voltage across the transistor 54 and the diode 59 would be less than the required 0.9 volts and the transistor 72 made non-conductive, thereby extinguishing the L.E.D. 80.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US43113774A | 1974-01-07 | 1974-01-07 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1499581A true GB1499581A (en) | 1978-02-01 |
Family
ID=23710644
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB17175A Expired GB1499581A (en) | 1974-01-07 | 1975-01-03 | Fire detector |
Country Status (5)
Country | Link |
---|---|
JP (1) | JPS5726398B2 (en) |
DE (1) | DE2500435A1 (en) |
FR (1) | FR2257119B3 (en) |
GB (1) | GB1499581A (en) |
IT (1) | IT1023231B (en) |
-
1974
- 1974-10-14 FR FR7434510A patent/FR2257119B3/fr not_active Expired
- 1974-11-08 JP JP12886674A patent/JPS5726398B2/ja not_active Expired
- 1974-11-12 IT IT5401174A patent/IT1023231B/en active
-
1975
- 1975-01-03 GB GB17175A patent/GB1499581A/en not_active Expired
- 1975-01-07 DE DE19752500435 patent/DE2500435A1/en active Pending
Also Published As
Publication number | Publication date |
---|---|
DE2500435A1 (en) | 1975-07-17 |
JPS50103300A (en) | 1975-08-15 |
JPS5726398B2 (en) | 1982-06-04 |
FR2257119A1 (en) | 1975-08-01 |
FR2257119B3 (en) | 1977-07-22 |
IT1023231B (en) | 1978-05-10 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4302753A (en) | Multi-function combustion detecting device | |
GB1401146A (en) | Fire alarm system with remote central station | |
GB1510085A (en) | Fluid flow detector for a fire alarm system | |
ES415905A1 (en) | Ionization-type fire sensor | |
GB1295498A (en) | ||
GB1469382A (en) | Critical liquid-level warning circuit | |
GB1430891A (en) | Ionization fire sensors | |
GB2157871A (en) | Apparatus for providing an environmental alarm indication | |
US3964036A (en) | Ionization smoke detector co-used to issue fire alarm and detect ambient atmosphere | |
US4020479A (en) | Fire detector | |
GB1367642A (en) | Proximity alarm system | |
US3049699A (en) | Sound actuated detection and alarm system | |
GB1499581A (en) | Fire detector | |
GB1200120A (en) | Improvements in or relating to fire alarms | |
US3155954A (en) | Automatic sensitivity control for sound actuated detection and alarm systems | |
US3754219A (en) | High impedance gaseous ion sensing and detection system | |
US2464211A (en) | Smoke detector and signal for airplanes | |
GB1494363A (en) | Line supervisory system | |
GB1215814A (en) | Ionization chamber detection apparatus. | |
EP0384209A3 (en) | Method for the operation of an ionization smoke detector, and ionization smoke detector | |
GB1379204A (en) | Flamedetection methods and apparatus | |
US3868663A (en) | Smoke detecting apparatus with multiple detectors connected to coincidence circuit | |
IE792181L (en) | Ionisation type fire detector | |
US4238677A (en) | Smoke detector by ionization associated to a velocimetric measurement electronic circuit | |
GB1144624A (en) | Improvements in or relating to improved fire detection device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PCNP | Patent ceased through non-payment of renewal fee |