GB1343819A - Fire alarm monitor - Google Patents
Fire alarm monitorInfo
- Publication number
- GB1343819A GB1343819A GB1343819DA GB1343819A GB 1343819 A GB1343819 A GB 1343819A GB 1343819D A GB1343819D A GB 1343819DA GB 1343819 A GB1343819 A GB 1343819A
- Authority
- GB
- United Kingdom
- Prior art keywords
- contact
- contacts
- fault
- relay
- thyristor
- 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
- G08B29/02—Monitoring continuously signalling or alarm systems
- G08B29/06—Monitoring of the line circuits, e.g. signalling of line faults
Landscapes
- Engineering & Computer Science (AREA)
- Computer Security & Cryptography (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fire Alarms (AREA)
Abstract
1343819 Fire alarms WALTER KIDDE CO Ltd 15 Feb 1972 [25 May 1971] 17066/71 Heading G4N In an alarm system having a plurality of units 3, 4 each having a normally open contact AA, BB, connected across a line 1 and closed in response to an unwanted condition and a normally closed contact A, B, connected in series with line 1 and opened in response to a fault in the units 3, 4, at least one of the normally closed contacts B is bridged by a circuit including a fault indicator 11 and having an impedance such that operation of normally opened contacts, such as AA, will still be detected despite opening of contact B. As described, the standing current in line 1, as determined by resistor 2, is sufficient to maintain transistor 7 conductive and fault relay RL1 energized. In the event of a fire, one of contacts AA, BB, closes so as to energize alarm relay RL2, which is held in by contact 5 and operates bells or a lamp. A fault in one of alarm units 4 causes opening of the normally closed contact B which would prevent detection of the closure of subsequent normally open contacts such as AA. A circuit comprising thyristor 8 and resistor 9 is therefore included which operates an indicator lamp 11 when contact B opens. Resistor 9 has such a value that the opening of contacts B will be detected by the de-energization of transistor 7 and fault relay RL1, but the alarm relay RL2 will still be operated in the event of closure of contact AA. Diode 10 protects the gate circuit of thyristor 8. Thyristor 8 may be replaced by a reed relay or Darlington pair.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1706671 | 1971-05-25 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1343819A true GB1343819A (en) | 1974-01-16 |
Family
ID=10088655
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1343819D Expired GB1343819A (en) | 1971-05-25 | 1971-05-25 | Fire alarm monitor |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB1343819A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4130732A (en) * | 1977-05-12 | 1978-12-19 | George Giovagnoni | Remote alarm reset apparatus |
GB2134680A (en) * | 1983-02-02 | 1984-08-15 | Sound Diffusion Plc | Monitored line alarm systems |
FR2894054A1 (en) * | 2005-11-29 | 2007-06-01 | Eurocopter France | Thermal detection and visual alarm unit, for aircraft, has multiple thermal switches with closes contacts connected in series with respective green and red lamps to form two terminal circuits |
-
1971
- 1971-05-25 GB GB1343819D patent/GB1343819A/en not_active Expired
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4130732A (en) * | 1977-05-12 | 1978-12-19 | George Giovagnoni | Remote alarm reset apparatus |
GB2134680A (en) * | 1983-02-02 | 1984-08-15 | Sound Diffusion Plc | Monitored line alarm systems |
FR2894054A1 (en) * | 2005-11-29 | 2007-06-01 | Eurocopter France | Thermal detection and visual alarm unit, for aircraft, has multiple thermal switches with closes contacts connected in series with respective green and red lamps to form two terminal circuits |
CN101002982B (en) * | 2005-11-29 | 2012-06-27 | 尤洛考普特公司 | On-board thermostat and a system for detecting excess temperature |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PCNP | Patent ceased through non-payment of renewal fee |