GB964386A - Improvements in fire-detection systems - Google Patents

Improvements in fire-detection systems

Info

Publication number
GB964386A
GB964386A GB4062662A GB4062662A GB964386A GB 964386 A GB964386 A GB 964386A GB 4062662 A GB4062662 A GB 4062662A GB 4062662 A GB4062662 A GB 4062662A GB 964386 A GB964386 A GB 964386A
Authority
GB
United Kingdom
Prior art keywords
test
heat
alarm
comparator circuit
critical temperature
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
GB4062662A
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of GB964386A publication Critical patent/GB964386A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/06—Electric actuation of the alarm, e.g. using a thermally-operated switch
    • 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
    • G08B29/12—Checking intermittently signalling or alarm systems
    • G08B29/14—Checking intermittently signalling or alarm systems checking the detection circuits
    • G08B29/145—Checking intermittently signalling or alarm systems checking the detection circuits of fire detection circuits

Landscapes

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

Abstract

964,386. Testing alarm circuits. J. E. LINDBERG. Oct. 26,1962 [Nov. 1, 1961 (2)], No. 40626/62. Heading G1V. [Also in Division G4] A fire detection system comprises a heat sensor 3 having two electrical conductors 4 and 5 spaced apart by a heat sensitive material 6 which is of low electrical conductivity below a critical temperature and is more conductive above this critical temperature, and the heat sensor is connected in a comparator circuit with a first source of potential 9 and a warning device 7 so that heating of the heat sensor by fire causes unbalance in the comparator circuit, and actuates the alarm. According to the invention, in order to test the system the conductor 5 of the heat sensor can be connected temporarily to a second source of potential 20, by means of a switch 12 to heat the sensitive material above the critical temperature so that the warning device in the comparator circuit will be actuated. In carrying out the test with the embodiment shown in Fig. 2, the switch 12 is set in the "test" position so that the wire is heated to above its critical temperature, and then set to the "operate" position. If all parts of the system are acting correctly, the alarm 7 will ring. The alarm is prevented from ringing during the "test" part of the operation by including a blocking condenser 18 in the comparator circuit and operating the resistance bridge from an A.C. power supply. Alternatively the bridge power supply may be D.C., the test power supply A.C. and the condenser replaced by an inductance (Fig. 3 not shown). An embodiment containing no arrangements for preventing the alarm ringing when the switch 12 is in the test position is also described (Fig. 1 not shown). Examples of the heat sensitive material included in the heat sensor are given; these include sodium or potassium nitrate inside a copper tube with an axial copper wire, barium and strontium oxide or heat resistive compounds in bead form separating a pair of wires inside a tubular cable.
GB4062662A 1961-11-01 1962-10-26 Improvements in fire-detection systems Expired GB964386A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US14942861A 1961-11-01 1961-11-01
US14931261A 1961-11-01 1961-11-01

Publications (1)

Publication Number Publication Date
GB964386A true GB964386A (en) 1964-07-22

Family

ID=26846627

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4062662A Expired GB964386A (en) 1961-11-01 1962-10-26 Improvements in fire-detection systems

Country Status (1)

Country Link
GB (1) GB964386A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2413729A1 (en) * 1978-01-02 1979-07-27 Metafix Sa Electronic monitoring system for security arrangements - compares measured quantity with standard value and allows for temp. variation

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2413729A1 (en) * 1978-01-02 1979-07-27 Metafix Sa Electronic monitoring system for security arrangements - compares measured quantity with standard value and allows for temp. variation

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