GB1200120A - Improvements in or relating to fire alarms - Google Patents
Improvements in or relating to fire alarmsInfo
- Publication number
- GB1200120A GB1200120A GB59190/67A GB5919067A GB1200120A GB 1200120 A GB1200120 A GB 1200120A GB 59190/67 A GB59190/67 A GB 59190/67A GB 5919067 A GB5919067 A GB 5919067A GB 1200120 A GB1200120 A GB 1200120A
- Authority
- GB
- United Kingdom
- Prior art keywords
- detector
- fire
- resistor
- ionization chamber
- feedback
- 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
- 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
1,200,120. Fire alarms. CERBERUS A.G. 29 Dec., 1967 [29 Dec., 1966], No. 59190/67. Heading G4N. [Also in Division G1] A fire alarm comprises a smoke, temperature or radiation detector 1 feeding an amplifier (such as 4, 8) having feedback arranged so that a change in the condition of detector 1 is maintained until the system is reset. Detector 1 may be an ionization chamber or photocell; field-effect transistor 4 and junction transistor 8 being normally non-conductive. The occurrence of a fire causes the resistance of detector 1 to increase, driving transistors 4, 8 into conduction and providing an indication on a meter 9. This condition is maintained by feedback across resistor 3 which reduces the energizing voltage of the ionization chamber 1. The threshold at which the circuit operates is adjustable by resistor 6. A plurality of such circuits may be connected across terminals 10, 12, 15 to feed a common indicator 9; the circuits being tested by momentary operation of a switch 17 which provides an indication on a meter 19 should any one detector fail. In Fig. 4 (not shown) a further transistor 21 is shunted across resistor 6 so as to reduce the threshold in the event of a fire. Transistors 4, 8 also become inherently conductive in the event of an increase in ambient temperature. If a photo-cell is used as detector 1, the circuit may operate a light source, optical feedback being provided between the lamp and the photo-cell. Fig. 1 (not shown) relates to a known alarm comprising an ionization chamber coupled via a field-effect transistor and Zener diode to an indicator controlled by a thyristor.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH1875166A CH468683A (en) | 1966-12-29 | 1966-12-29 | Fire alarms with an electrical feedback arrangement |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1200120A true GB1200120A (en) | 1970-07-29 |
Family
ID=4435069
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB59190/67A Expired GB1200120A (en) | 1966-12-29 | 1967-12-29 | Improvements in or relating to fire alarms |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US3559196A (en) |
| AT (1) | AT278597B (en) |
| BE (1) | BE707959A (en) |
| CH (1) | CH468683A (en) |
| DK (1) | DK122548B (en) |
| GB (1) | GB1200120A (en) |
| SE (1) | SE330659B (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3946374A (en) * | 1970-08-13 | 1976-03-23 | Sci Systems, Inc. | Rate-of-change combustion and contamination detection device |
| JPS4940290Y1 (en) * | 1970-11-19 | 1974-11-05 | ||
| US3866195A (en) * | 1973-05-07 | 1975-02-11 | Fire Alert Company | Combustion product detector and method of calibrating |
| DE2327497C3 (en) * | 1973-05-30 | 1981-12-24 | Benno 5430 Wettingen Aargau Perren | Detector for changes in resistance with a downstream alarm device |
| US4109240A (en) * | 1973-11-26 | 1978-08-22 | Cerberus Ag. | Ionization-type fire sensing system |
| DE2546970C3 (en) * | 1975-10-20 | 1981-09-10 | Preussag Ag Feuerschutz, 2060 Bad Oldesloe | Ionization smoke detector |
| DE2707409C2 (en) * | 1977-02-21 | 1985-02-21 | Hartwig Dipl.-Ing. 2409 Scharbeutz Beyersdorf | Ionization fire detector |
| DE2726186C3 (en) * | 1977-06-10 | 1981-05-14 | Pan Data Ab, Stockholm | Electrical monitoring device |
| US8101130B2 (en) * | 2006-09-15 | 2012-01-24 | Applied Nanotech Holdings, Inc. | Gas ionization source |
| US9564045B2 (en) * | 2014-04-14 | 2017-02-07 | Stephen D. Ainsworth | Alarm system testing device |
-
1966
- 1966-12-29 CH CH1875166A patent/CH468683A/en unknown
-
1967
- 1967-02-01 AT AT93567A patent/AT278597B/en not_active IP Right Cessation
- 1967-12-14 BE BE707959D patent/BE707959A/xx not_active IP Right Cessation
- 1967-12-27 US US693937A patent/US3559196A/en not_active Expired - Lifetime
- 1967-12-28 SE SE17925/67A patent/SE330659B/xx unknown
- 1967-12-28 DK DK656167AA patent/DK122548B/en not_active IP Right Cessation
- 1967-12-29 GB GB59190/67A patent/GB1200120A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| SE330659B (en) | 1970-11-23 |
| US3559196A (en) | 1971-01-26 |
| BE707959A (en) | 1968-04-16 |
| CH468683A (en) | 1969-02-15 |
| DE1566687B1 (en) | 1971-04-01 |
| DK122548B (en) | 1972-03-13 |
| AT278597B (en) | 1970-02-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |