EP 0772852 A1 19970514 - IMPROVEMENTS RELATING TO OPTICAL SMOKE DETECTORS
Title (en)
IMPROVEMENTS RELATING TO OPTICAL SMOKE DETECTORS
Title (de)
OPTISCHER RAUCHMELDER
Title (fr)
PERFECTIONNEMENTS AUX DETECTEURS OPTIQUES DE FUMEES
Publication
Application
Priority
- FR 9501014 W 19950727
- FR 9409473 A 19940729
Abstract (en)
[origin: WO9604627A1] The device for detecting the presence of smoke (F) comprises a dark chamber (1) into which the smoke to be detected passes, a source (L) capable of producing in said chamber a light beam formed from pulses of short duration spaced from one another by identical much longer intervals, a detector (D) for generating response signals related to successive light pulses being partially reflected by the smoke, and means for comparing these signals with a threshold and setting off an alarm if the threshold is exceeded by several successive signals. The device also comprises means (4-8, 15, 16) for automatically increasing the pulsing frequency as soon as a signal exceeding the threshold is detected. Optional triggering of an alarm is then initiated on the basis of the signals generated by the detector in response to successive pulses at the increased frequency.
IPC 1-7
IPC 8 full level
G01N 21/53 (2006.01); G08B 17/107 (2006.01)
CPC (source: EP US)
G08B 17/107 (2013.01 - EP US)
Citation (search report)
See references of WO 9604627A1
Designated contracting state (EPC)
BE DE ES GB
DOCDB simple family (publication)
WO 9604627 A1 19960215; DE 69506417 D1 19990114; EP 0772852 A1 19970514; EP 0772852 B1 19981202; ES 2126915 T3 19990401; FR 2723233 A1 19960202; FR 2723233 B1 19961004; JP H11509341 A 19990817; US 5864293 A 19990126
DOCDB simple family (application)
FR 9501014 W 19950727; DE 69506417 T 19950727; EP 95926440 A 19950727; ES 95926440 T 19950727; FR 9409473 A 19940729; JP 50624696 A 19950727; US 77636997 A 19970414