Method and apparatus for detecting flame with adjustable optical coupling

摘要

A method of detecting flame within a region where flame is expected. Radiation emissions from the region are measured within selected portions of the visible and infra-red frequency bands. Spectral characteristics of the two measurements, including their auto spectra, coherency and transfer function, are derived. The derived spectral characteristics are compared with prestored spectral signatures representative of the spectral characteristics of radiation emitted from the region within the selected portions of the visible and infra-red frequency bands while known flame conditions prevail within the region-thereby estimating the deviation of the derived spectral characteristics from the prestored spectral signatures. The deviations aforesaid are compared with predetermined threshold alarm values to assess the presence or absence of flame.