The FDK series photoelectric smoke detectors detect combustion products (smoke) generated by a fire, and transmit an alarm signal to the fire alarm control panel. The photoelectric smoke detector can detect a fire in an earlier stage than a heat detector. Generally, this detector is installed in the spaces such as basements, ordinary floors, corridors, staircases, elevator shafts.
OPERATING PRINCIPLE AND FUNCTION
The photoelectric smoke detector is composed of a light source, light sensing element, Light shielding element and detecting chamber. The light source (a light-emitting diode) emits light at intervals of about 3.5 seconds, which does not reach the light sensing element (photo diode) under normal conditions because of the light shielding mold. If smoke enters the detecting light reaching the light sensing element varies with smoke density and if it exceeds the chamber, the light from the light source is scattered by smoke particles and reaches the light sensing element. The light reaching the light sensing element varies with smoke density and if it exceeds the predetermined level, the detector operates and automatically holds its operation. The detector then transmits the alarm signal to the fire alarm panel and the response lamp of the detector turns on.