| 摘要 |
<p>Aflame monitor for a burner (10) comprises an oscillator (30) which generates a signal'at a characteristic frequency (f), a flame modulator (26 or 36) connected to the oscillator (30) and the burner (10) for modulating the flame, which produces an electromagnetic signal at the same frequency, and a signal detector (34) for detecting the electromagnetic signal. A bandpass filter (40) is connected to the detector (34) for passing only the signal at the characteristic frequency. Circuitry (44,46) is provided for detecting the intensity of the electromagnetic signal, which is proportional to the flame temperature and which can be used to control the fuel or air supplied to the burner and thus optimise the flame. A single detector can be used to detect the flame from various burners where each burner is supplied with its own characteristic frequency and the detector is multiplexed to share its operation over the various burners. A pressure wave detector is also provided to detect the intensity of a pressure wave in the flame, which intensity is divided into the electromagnetic radiation intensity to provide a calibration signal.</p> |
