Wenderoth, Lind & Ponack
Smoke detecting apparatus for fire alarm
 A smoke detecting apparatus includes a lamp, a light receiving element for receiving light from the lamp, and a smoke detecting circuit for detecting the smoke density in accordance with the signal outputted from the light receiving element. The apparatus further includes a light emission failure detector and counter for detecting a light emission failure in which the lamp fails to emit light in response to a light emission instruction from the smoke detecting and counting light emission failures, and a memory for storing the number of light emission failures. The apparatus may further include a warning unit which, when the number of failures becomes a predetermined value or more, warns that the lamp will soon be exhausted. Thus, the unit enables a maintenance person to replace the lamp without fail before it is exhausted. 
Nohmi Bosai Ltd.
H G G
H05B G01R G08B
inventional inventional inventional
Hideo Ryousaku Mikio
Ito Kobayashi Mochizuki