EP 0130992 B1 19870408 - PHOTOELECTRIC SMOKE DETECTOR
Title (en)
PHOTOELECTRIC SMOKE DETECTOR
Publication
Application
Priority
CH 11983 A 19830111
Abstract (en)
[origin: WO8402790A1] In a photoelectric smoke detector, a radiation source (2) is intermittently actuated by a control unit (1) and the radiation on which smoke particles have an influence, for example the diffused radiation, is picked up by a radioreceiver (9). The signal from the radioreceiver (9) is supplied to a signal processing unit (11) simultaneously actuated by the control unit (1) having a phase sensitive unit which reverses the received signal according to the phase position of the signal from the control unit (1) and supplies the signal thus modified to an integration unit of which the integrated output signal actuates a display unit (13); the latter may for example provide an alarm signal when the integrated signal, that is the fume density, exceeds a predetermined threshold value, or may display the smoke density. Thereby, low smoke signals may be safely and reliably detected, even when they are completely covered by background noise. Such a fume detector may be conveniently used as a sensitive and reliable fire warning device.
IPC 1-7
IPC 8 full level
G01N 21/53 (2006.01); G01N 21/59 (2006.01); G08B 17/10 (2006.01); G08B 17/107 (2006.01); G08B 29/00 (2006.01); G08B 29/18 (2006.01)
IPC 8 main group level
G08B (2006.01)
CPC (source: EP US)
G08B 17/107 (2013.01 - EP US); G08B 29/185 (2013.01 - EP US); G08B 29/22 (2013.01 - EP US); G08B 17/113 (2013.01 - EP US)
Designated contracting state (EPC)
CH DE FR GB LI SE
DOCDB simple family (publication)
WO 8402790 A1 19840719; CH 660244 A5 19870331; DE 3370888 D1 19870514; EP 0130992 A1 19850116; EP 0130992 B1 19870408; JP H0568000 B2 19930928; JP S60500467 A 19850404; NO 159424 B 19880912; NO 159424 C 19881221; NO 842034 L 19840719; US 4647786 A 19870303
DOCDB simple family (application)
CH 8300112 W 19831005; CH 11983 A 19830111; DE 3370888 T 19831005; EP 83902981 A 19831005; JP 50309183 A 19831005; NO 842034 A 19840522; US 60682784 A 19840416