Patent ID: 6326897
Filing Date: 2001-12-04
Classification: G08B

Abstract:
A particle detector, comprising:a housing defining a dark chamber, the chamber admitting test atmosphere;a scatter emitter/receiver combination disposed within the chamber, the scatter emitter positioned such that any portion of the light emitted by the scatter emitter that is reflected off of particles suspended in the atmosphere and received is proportional to the amount of high reflectivity particles present in the atmosphere;an obscuration emitter/receiver combination disposed within the chamber, the obscuration emitter positioned such that any portion of the light emitted by the obscuration emitter that is received is inversely proportional to the amount of low reflectivity particles present in the atmosphere; anda controller coupled to the scatter emitter/receiver combination and the obscuration emitter/receiver combination, the controller using the amount of particles sensed by the obscuration emitter/receiver combination to alter the sensitivity of the scatter emitter/receiver combination.