Smoke detector system with self-diagnostic capabilities and repl

Details Smoke detector system with self-diagnostic capabilities and repl Smoke detector system with self-diagnostic capabilities and repl

1993-08-19

1996-08-13

Hofsass, Jeffery

Communications: electrical

Condition responsive indicating system

Specific condition

340630, 340693, 250574, G08B 17107

Patent

active

055460747

ABSTRACT:
A self-contained smoke detector system has internal self-diagnostic capabilities and accepts a replacement smoke intake canopy (14) without a need for recalibration. The system includes a microprocessor-based self-diagnostic circuit (200) that periodically checks sensitivity of the optical sensor electronics (24, 28) to smoke obscuration level. By setting tolerance limits on the amount of change in voltage measured in clean air, the system can provide an indication of when it has become either under-sensitive or over-sensitive to the ambient smoke obscuration level. An algorithm implemented in software stored in system memory (204) determines whether and provides an indication that for a time (such as 27 hours) the clean air voltage has strayed outside established sensitivity tolerance limits. The replaceable canopy is specially designed with multiple pegs (80) having multi-faceted surfaces (110, 112, 114). The pegs are angularly spaced about the periphery in the interior of the canopy to function as an optical block for external light infiltrating through the porous side surface (64) of the canopy and to minimize spurious light reflections from the interior of the smoke detector system housing (10) toward a light sensor photodiode (28). The pegs are positioned and designed also to form a labyrinth of passageways (116) that permit smoke to flow freely through the interior of the housing.

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FIG. 1 Diagram of Apollo Fire Detectors Series 60 and 95 Smoke Detector Housings, 1991.
FIG. 2 Diagram of ESL Model 447 Smoke Detector Housing, 1991.
FIG. 3 Diagram of ESL Model 320 Smoke Detector Chamber, 1981.
FIG. 4 Diagram of ESL Model 445 Smoke Detector Housing, 1985.
FIG. 5 Diagram of ESL Model 611 Smoke Detector Housing, 1990.
FIGS. 6A and 6B Diagrams of Apollo Fire Detectors Model 800 Smoke Detector Chamber, 1988.
FIG. 7 Diagram of BRK Notifier Model SDX-551 Smoke Detector Chamber, 1984.

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