| 摘要 |
A flame sensor comprises a filter which blocks light in an infrared ray region, a filter which blocks stray light, a narrow band filter which passes only light of a band corresponding to a line spectrum of carbonic acid gas resonance radiation generated by a flame, and a broad band filter which passes light of a band which is broader than the band corresponding to the line spectrum, and a plurality of light reception elements which convert lights passing through the narrow and broad band filters to electric signals, the flame sensor judging flame when a difference between intensities of the electric signals is equal to or more than a predetermined value and a ratio between the intensities of the electric signals is within a predetermined range, by assuming that transmission band widths of the narrow and broad band filters are equal, is provided.
|
