Flame detecting arrangement for detecting a flame through horizontal and vertical scanning of a supervisory region by using a photodetector

摘要

A flame detecting apparatus and a flame detecting method which utilizes a flame detector having a directivity and provided with a photodetector such as a photodiode or a phototransistor which produces a photo-output in response to the intensity of light incident thereupon. The flame detector is scanned sequentially in the horizontal and the vertical direction within a supervisory region. When a photo-output from said flame detector obtained in the horizontal or vertical scanning by said scanning means exceeds a predetermined threshold value, one of the horizontal and the vertical scanning is suspended, while repeating the other, vertical or horizontal, scanning at the same horizontal or vertical position several times. Flame determination is made when the changes in the photo-outputs, which is obtained through the repeated scanning, exceed a predetermined value and they last over a predetermined scanning angle.