ABB flame detection fiber SF810 series, with many years of research and development experience. Principle of Infrared Flame Detector: There is a large amount of visible light in the flame and infrared rays above 0.9m. These wavelengths of light are not easily absorbed by coal dust, water vapor, and other combustion products, so it is suitable for detecting pulverized coal flame, heavy oil flame, and suitable combustion of a fuel with a large inert gas content. Infrared flame detection determines the presence of flame by detecting the intensity of the infrared rays emitted by the combustion flame and the flame frequency. The probe uses a lead sulfide photocell or a silicon photodiode. Since the furnace flicker is completely burned in the flame zone, the flame flicker frequency usually does not exceed 2HZ. Therefore, the infrared flame detector can distinguish between the burner flame and the background flame through the filter circuit.