Global Patent Index - EP 0011461 A1

EP 0011461 A1 19800528 - An improved fire detection system.

Title (en)

An improved fire detection system.

Title (de)

Ein verbessertes Feuerdetektionssystem.

Title (fr)

Système perfectionné de détection du feu.

Publication

EP 0011461 A1 19800528 (EN)

Application

EP 79302527 A 19791112

Priority

GB 7843944 A 19781110

Abstract (en)

A monitoring system for detecting fire or other elevated temperature conditions in a plurality of discrete zones Z1, Z2, Z3, etc. comprises a loop box 1 which has two pairs of terminals A and B to each of which is connected one end of a pair of conductors of a linear temperature detector cable passing through each of the discrete zones. Adjacent zones are sectionalised by zone boxes 9, each of which comprises a pair of balanced resistors, one resistor connected in series in one conductor of the loop and the other resistor being connected in series in the other conductor. The loop box 1 has a constant current generator 2 which can be connected via an electronic switch 3 to either the A or B end of the loop 4; an electronic switch 5 which connects one of two fixed resistors 6 directly across the two conductors of the loop at the opposite end to that to which the generator 2 is connected; and an electronic switch 7 which connects a voltage measuring circuit 8 onto the terminals of the loop to which the generator 2 is connected. Electronic switches 3, 5 and 7 are operated by control circuits 10 whose output signals are fed to a display device 11, which shows if the system is operating normally, identifies the nature of any abnormalities and indicates any discrete zone in which there is a short circuit caused by a fire, and to external alarms.

IPC 1-7

G08B 17/06; G08B 25/00

IPC 8 full level

G08B 17/06 (2006.01); G08B 25/01 (2006.01); G08B 25/04 (2006.01)

CPC (source: EP)

G08B 17/06 (2013.01); G08B 25/018 (2013.01); G08B 25/045 (2013.01)

Citation (search report)

Designated contracting state (EPC)

BE DE FR IT NL SE

DOCDB simple family (publication)

EP 0011461 A1 19800528

DOCDB simple family (application)

EP 79302527 A 19791112