Smoke alarm with infrared coverage monitoring

摘要

The alarm has a smoke chamber including an upper part (7) provided with smoke inlet openings (11). Measuring electronic units (13, 15) generate an evaluated measuring signal during detection of smoke particles. Four infrared (IR) transmitter diodes (1) are arranged in a housing (10). Transmitted signals from the diodes pass into an interior of the chamber by the opened or partially covered smoke inlet openings. An IR receiver diode (2) receives the signals. A partial covering of the openings is closed upon interruption or reduction of the received transmitted signals at the receiver diode. An independent claim is also included for a method for operating a smoke alarm.