System and Method for Detection of Flame in Furnace

摘要

The presence of a flame from a burner is determined by analyzing the signal produced by a radiation sensor (12) aimed at a burner. The signal produced by the radiation sensor (12) is applied to the analog input of a microcomputer (50) and processed therein. Specifically, a Fourier transformation is applied to the signal producing amplitude values for a spectrum of component frequencies produced by changes in the power of the flame over time. A logarithmic value is derived for each of the amplitude values. The degree of linearity of the distribution of the component frequency logarithmic amplitude values provides an indication of the flame presence. Several parameters, including integrated linear error, linearity regression correlation and slope difference, provide an indication of the degree of linearity. A plurality of values for each of these parameters are produced during an interval of time. When a given percentage of the parameter values are above their respective thresholds the flame is determined to be present, whereas when another given percentage of the parameter values are below their respective threshold the flame is determined to be extinguished. IMAGE