Optical smoke detector

摘要

An optical smoke detector (110) is provided that comprises a housing (112) having a base (114) for attaching the detector to a surface and a cover (116) having a side wall (124) and a bottom wall (126) defining the interior of said cover. An optical sensor (131) is provided for generating a signal representative of the detected light and a control circuit (130) is provided for controlling operation of the detector. The control circuit (130) includes a plurality of temperature sensors (D1, D2) for sensing a rise in ambient temperature and generating a signal representative thereof. The temperature sensors (D1, D2) are located above an internal surface of said bottom wall (126) within the housing and are substantially equally spaced. The control circuit (30) is operable to compare said representative signal with a reference signal and generate an alarm signal in dependence thereon.

主权项

1. An optical smoke detector comprising:
a housing having a base configured for attaching said detector to a surface, and a cover having a side wall and a bottom wall defining an interior of said cover; an optical sensor for generating a signal representative of detected light; and a control circuit for controlling operation of the detector; wherein: said control circuit includes a plurality of temperature sensors for sensing a rise in ambient temperature caused by a fire and generating a signal representative thereof, and wherein said control circuit is configured to adjust the sensitivity of the optical sensor in dependence on a comparison of said representative signal from the temperature sensors with a reference value and in dependence on a comparison of voltage and rate of change of voltage of said representative signal from the temperature sensors to change the threshold at which smoke is detected; said temperature sensors are located above an internal surface of said bottom wall within the housing and are substantially equally spaced; and said control circuit is configured to compare said signal representative of detected light with a reference signal and generate an alarm signal in dependence thereon.