Global Patent Index - EP 0856828 A3

EP 0856828 A3 2000-01-05 - Alarm system

Title (en)

Alarm system

Title (de)

Alarmsystem

Title (fr)

Système d'alarme

Publication

EP 0856828 A3 (EN)

Application

EP 98300392 A

Priority

GB 9701941 A

Abstract (en)

[origin: EP0856828A2] A fire alarm system comprises control panel 13, first and second two-wire alarm circuits 17,18 extending from the control panel 13 into respective zones, each alarm circuit comprising a plurality of combined detector and sounder devices 10 connected in parallel across the wires 11,12 of the circuit. Upon detection of smoke or heat in one of the zones, the activated device 10 is arranged to draw a pulsed current from the control panel 13, which can be detected to trigger an alarm condition in the control panel 13, whereupon the control panel 13 applies an alarm signal circuit to the alarm circuits 17,18 of both zones, so as to energise the sounders of all devices 10. The pulsed current that is drawn by the devices 10 when they are activated by heat or smoke means that any further change in current that is caused when more devices 10 are activated as the fire spreads will be detected by the control panel 13, despite the heavy current being drawn by the energised sounders. <IMAGE>

IPC 1-7

G08B 25/01

IPC 8 full level

G08B 25/01 (2006.01)

CPC

G08B 25/018 (2013.01)

Citation (search report)

DCS

AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

DOCDB simple family

EP 0856828 A2 19980805; EP 0856828 A3 20000105; EP 0856828 B1 20040303; DE 69822010 D1 20040408; GB 2321747 A 19980805; GB 2321747 B 20001018; GB 9701941 D0 19970319