Slc Technologies

General Electric Company

General Electric Corporation Gmbh

Sentrol, Inc.

Brian Andrew Bernal

Douglas Henry Marman

Kirk Rodney Johnson

Robert Gerard Fischette

Mark A Peltier

Daniel P Croft

A self-contained smoke detector system has internal self-diagnostic capabilities and accepts a replacement smoke intake canopy ( ) without a need for recalibration. The system includes a microprocessor-based self-diagnostic circuit ( ) that periodically checks sensitivity of the optical sensor electronics ( ) 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 ( ) 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 ( ) having multi-faceted surfaces ( ). 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 ( ) of the canopy and to minimize spurious light reflections from the interior of the smoke detector system housing ( ) toward a light sensor photodiode ( ). The pegs are positioned and designed also to form a labyrinth of passageways ( ) that permit smoke to flow freely through the interior of the housing.

Self-diagnostic smoke detector

Automatic verification of smoke detector operation within calibration limits

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.

Method of automatic verification of smoke detector operation within

Self-diagnosing smoke detector assembly

A smoke detector (10) has internal self-adjustment and self-diagnostic capabilities. It includes a microprocessor-based alarm control circuit (24) that periodically checks the sensitivity of a smoke sensing element (20) to a smoke level in a spatial region (12). The alarm control circuit and the smoke sensor are mounted in a discrete housing (25) that operatively couples the smoke sensor to the region. The microprocessor (30) implements a routine (50) stored in memory (32) by periodically determining a floating adjustment (FLT.sub.-- ADJ) that is used to adjust the output (RAW.sub.-- DATA) of the smoke sensing element and of any sensor electronics (40) to produce an adjusted output (ADJ.sub.-- DATA) for comparison with an alarm threshold. The floating adjustment is not greater than a maximum value (ADJISENS) or less than a minimum value (ADJSENS). Except at power-up or reset, each floating adjustment is within a predetermined slew limit of the immediately preceding floating adjustment. The floating adjustment is updated with the use of averages (NEW.sub.-- AVG) of selected signal samples taken during data gathering time intervals having a data gathering duration that is long in comparison to the smoldering time of a slow fire. The adjusted output is also used for self-diagnosis.

Self-adjusting smoke detector with self-diagnostic capabilities

Smoke detector system with self-diagnostic capabilities and replaceable

Growing community of inventors

Portland, OR, United States of America

Brian Andrew Bernal