Abstract: A method for monitoring a combustion process in the infrared wavelength range includes using a laser, which transmits a laser light beam along a measurement path in a certain wavelength range, which is selected in such a way that a gas therein to be detected in the combustion process has an absorption line, and that the emission wavelength of the laser detects the absorption line of the gas to be detected upon the tuning in the selected wavelength range. The concentration of the gas is determined as a function of the absorbed energy of the laser light beam. The intensity of the laser light beam is detected and is analyzed in order to determine the existence of a flame in the combustion process, and/or the quality of the flame.

Abstract: A gas burner has a fan and a mixing device disposed at the suction side of the fan. The mixing device mixes the air taken in through an intake channel with a gas supplied to the intake channel through a gas inlet to form a gas-air mixture. The mixing device has a housing with an air inlet formed with cutouts for noise reduction.

Abstract: A capacitor connected to a voltage source is charged during a charging phase up to a voltage value, and during a discharging phase the capacitor is discharged via a coupling element connected to the flame sensor. The period for the charging or discharging phase of the capacitor respectively is selected in this case as a function of the characteristics of the flame sensor, especially of its impedance. For flame monitoring the charging and discharging of the capacitor is repeated cyclically, with the voltage signal obtained in this way being evaluated in single-channel mode with the aid of a threshold value.