GB1332270A - Fire detecting system - Google Patents

Fire detecting system

Info

Publication number
GB1332270A
GB1332270A GB1682272A GB1682272A GB1332270A GB 1332270 A GB1332270 A GB 1332270A GB 1682272 A GB1682272 A GB 1682272A GB 1682272 A GB1682272 A GB 1682272A GB 1332270 A GB1332270 A GB 1332270A
Authority
GB
United Kingdom
Prior art keywords
sensors
thyristor
fire
transistors
voltage
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
Application number
GB1682272A
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.)
Nittan Co Ltd
Original Assignee
Nittan Co Ltd
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 Nittan Co Ltd filed Critical Nittan Co Ltd
Publication of GB1332270A publication Critical patent/GB1332270A/en
Expired legal-status Critical Current

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
    • G08B29/185—Signal analysis techniques for reducing or preventing false alarms or for enhancing the reliability of the system
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B25/00—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems
    • G08B25/01—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium
    • G08B25/04—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium using a single signalling line, e.g. in a closed loop

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Fire Alarms (AREA)
  • Fire-Detection Mechanisms (AREA)

Abstract

1332270 Oscillator and switching circuits NITTAN CO Ltd 12 April 1972 [15 April 1971] 16822/72 Heading H3T [Also in Division G4] In a fire alarm system comprising a plurality of fire sensors 25 connected across a pair of conductors 30, 40 each sensor 25 turning on a normally-open switching device (such as thyristor 26) which switching device is only turned off by reducing the voltage between conductors 30, 40 and a central unit 1 for supplying an operation voltage to said sensors 25 and including first means for responding to the closure of any of said normally open switching devices 26 to produce an output voltage, second means for accumulating said output voltage and third means for producing an alarm in response to a predetermined amount of said accumulation. As described, sensors 25 may be responsive to smoke or temperature and are normally energized by transistor 19 and the Zener diode 24 acting as a voltage regulator. In the event of fire, one of sensors 25 turns on the respective thyristor 26, closing the emitter circuit of transistor 19 so that transistors 18 and 19 operate as a multivibrator because of their cross-coupling via capacitors 16, 17. The second half-cycle from the multivibrator turns off thyristor 26. If thyristor 26 is re-triggered by the continual presence of fire conditions, a train of pulses appears across resistor 15 which train is integrated by a circuit 7 and, when the integrated output is sufficient, transistors 33 and 37 are turned on, operating an audible alarm 42 and a relay 41. Transistors 33 and 37 are maintained conductive by feedback via diode 39. The invention prevents false alarms due to spurious triggering of thyristors 26 by short-duration pulses.
GB1682272A 1971-04-15 1972-04-12 Fire detecting system Expired GB1332270A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP46023446A JPS5136119B1 (en) 1971-04-15 1971-04-15

Publications (1)

Publication Number Publication Date
GB1332270A true GB1332270A (en) 1973-10-03

Family

ID=12110715

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1682272A Expired GB1332270A (en) 1971-04-15 1972-04-12 Fire detecting system

Country Status (9)

Country Link
US (1) US3775761A (en)
JP (1) JPS5136119B1 (en)
AU (1) AU452761B2 (en)
CA (1) CA948290A (en)
CH (1) CH554031A (en)
FR (1) FR2133747B1 (en)
GB (1) GB1332270A (en)
IT (1) IT954665B (en)
ZA (1) ZA721943B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2187870A (en) * 1986-03-14 1987-09-16 Nittan Co Ltd Alarm device for detecting abnormality

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS52116920A (en) * 1976-03-27 1977-09-30 Taisei Corp Method of preventing sedimentation of sludge in underground petroleum storing tanks and apparatus therefor
US4102194A (en) * 1976-09-20 1978-07-25 Dickey-John Corporation Electronic bin temperature monitor
JPS5471710U (en) * 1977-10-31 1979-05-22
US4287515A (en) * 1979-04-27 1981-09-01 Baker Industries, Inc. Fire detection system with multiple output signals
US4916432A (en) * 1987-10-21 1990-04-10 Pittway Corporation Smoke and fire detection system communication
US4814748A (en) * 1987-11-09 1989-03-21 Southwest Laboratories, Inc. Temporary desensitization technique for smoke alarms

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2903682A (en) * 1955-12-28 1959-09-08 Petcar Res Corp Flame detector system
US3147464A (en) * 1961-10-16 1964-09-01 Warren L Spielman First-out annunclator having input and supply control of indicator switching means
BE689837A (en) * 1964-09-29 1967-05-02
FR1565498A (en) * 1968-02-15 1969-05-02
US3719836A (en) * 1971-06-23 1973-03-06 C Possell Pressure sensitive sensor and control unit and method of using same
US3694670A (en) * 1971-10-26 1972-09-26 Joseph M Marzolf Easily switched silicon controlled rectifier

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2187870A (en) * 1986-03-14 1987-09-16 Nittan Co Ltd Alarm device for detecting abnormality
GB2187870B (en) * 1986-03-14 1990-01-17 Nittan Co Ltd Alarm device for detecting abnormality

Also Published As

Publication number Publication date
CH554031A (en) 1974-09-13
FR2133747A1 (en) 1972-12-01
AU452761B2 (en) 1974-08-23
CA948290A (en) 1974-05-28
FR2133747B1 (en) 1973-07-13
DE2218198A1 (en) 1972-10-26
US3775761A (en) 1973-11-27
DE2218198B2 (en) 1973-05-10
IT954665B (en) 1973-09-15
ZA721943B (en) 1972-12-27
AU4079072A (en) 1973-11-01
JPS5136119B1 (en) 1976-10-06

Similar Documents

Publication Publication Date Title
GB1338690A (en) Fire alarm system
US3699569A (en) Security system for indicating fire, intrusion or the like
US3676680A (en) Ionization fire alarm with insulation monitoring system
US2892181A (en) Vehicle burglar alarm
GB1433172A (en) Alarm systems
US4282519A (en) Interconnection of alarms of smoke detectors with distinguishable alarms
GB1401146A (en) Fire alarm system with remote central station
GB1412164A (en) Ionization-type fire sensor
GB1332270A (en) Fire detecting system
GB1182700A (en) Improvements in or relating to Electrical Supervisory Systems
US2684475A (en) Supervised signaling system
US4150369A (en) Intrusion alarm system
GB1202760A (en) Improvements in or relating to alarm signal installations
GB1270682A (en) Improvements in or relating to intruder alarm systems
US3268881A (en) Detection device
GB1514501A (en) Ionization-type fire detector
US4163968A (en) Supervised loop alarm radio transmitter system
SE330659B (en)
GB988106A (en) Condition responsive system
US3553730A (en) Security alarm system
EP0044725B1 (en) Improvements relating to security alarm systems
US1326304A (en) Automatic fire
US3508239A (en) Burglar alarm
EP0234116A1 (en) Alarm system
GB1134502A (en) A self-checking condition monitoring system

Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee