Abstract: A gasifier (17) is located at a distance (49) from an air aperture plate (35). At the outlet (42) of the gasifier there is a stationary mixing head (29) having a deflector section (31) and lateral outlets (33). Fuel is supplied coaxially through an opening (55) of the air aperture plate. A flame tube (21) surrounds the gasifier (17) and an electric heater (39) leaving an annular space (40). When the burner is started up, the electric heater (39) is switched on until the gasifier has the necessary operating temperature. Fuel is then supplied. The fuel/air mixture is ignited by an electrode (65). The flame tube (21) extends to the end of the mixing head (29), or only a little therebeyond. A flame is formed at the outlets (33) that touches the flame tube after a short travel, then emerges from it and expands. Because the flame can immediately expand, only little NO.sub.x is formed.

Abstract: A stationary gasifier (17) is located at a distance (49) from an air aperture plate (35). At the outlet (42) of the gasifier there is a stationary mixing head (29) having a deflector section (31) and lateral outlets (33). Fuel is supplied coaxially through an opening (55) of the air aperture plate. A flame tube (21) surrounds the gasifier (17) and an electric heater (39) leaving an annular space (40). When the burner is started up, the electric heater (39) is switched on until the gasifier has the necessary operating temperature. Fuel is then supplied. The fuel/air mixture is ignited by an electrode (65). The flame tube (21) extends to the end of the mixing head (29), or only a little therebeyond. A flame is formed at the outlets (33) that touches the flame tube after a short travel, then emerges from it and expands. Because the flame can immediately expand, only little NO.sub.x is formed.

Abstract: The burner has a motor, a fuel pump and a fan. An easily replaceable component unit (27), the drive shaft (33) of which is coupled to the burner motor, is surrounded by the flame tube (21). The component unit (27) has a drive shaft (33), supported in an adaptor sleeve (37), for driving the gasifier (17). When the burner is started up, the rotatable gasifier (17) is heated by the heater (39). Once the gasifier has reached a predetermined temperature, the supply of fuel takes place through the line segment (19') and through the nozzle (71) to the immediate vicinity of the inner wall of the gasifier (17). Because of the rapid rotation, the fuel is distributed over the entire inner wall of the gasifier (17) and evaporates. Particularly in the mixing head (29), the evaporated fuel mixes with the combustion air flowing in through the opening (77) and is directed radially to the outside by a deflector (31, 31').

Abstract: To prevent the formation of encrustations on a pH sensor in a combustion exhaust or flue gas washing apparatus, alkaline additives are added to the wash water which, upon contacting SO.sub.2 in the gases, form sulfite particles. The sulfite particles are prevented from depositing at the bottom of a collection vessel (11) in form of a mud, and, in accordance with the invention, rather are continuously stirred and recirculated in a closed recirculation loop to a spray device (25). The particles, upon being recirculated, will grow to form a granulate which, eventually, will deposit, the granulate, however, being constituted by granules substantially in excess of those which form a mud; the larger granules also prevent deposition of encrustations along the walls, and, for example, a pH sensor (47).