Patent ID: 8294587
Filing Date: 2012-10-23
Classification: G08B

Abstract:
1. A smoke detector comprising: a generally closed housing; a smoke sensor in the housing capable of detecting smoke therein; alarm device connected to the smoke sensor for generating an alarm when the smoke sensor detects smoke; a partition subdividing the housing into separate first and second chambers, the housing being formed with first and second smoke holes respectively allowing air from the exterior into the first and second chambers; a fan port in the partition; a sensor port in the partition spaced from the fan port; air-flow sensor device at or in the sensor port for detecting air flow through the sensor port; fan device in the fan port for drawing air from one of the chambers and forcing it into the other chamber, whereby, when the smoke hole of either chamber is at least partially blocked, air flow through the sensor port will be greater than when it is not partially blocked; and control device connected to the fan device and to the air-flow sensor device for operating the fan device to move air from the one chamber through the fan port into the other chamber and for generating an output when air flow through the sensor port exceeds a predetermined limit.