Air throttling device for forced draught burner, especially for multistage burner

摘要

Known air throttling devices in forced draught burners are butterfly valves which are mounted centrically or eccentrically and which, as an individual flap or multiple leaf damper, regulate the free cross-sectional area for the combustion air. Although this regulating system is very cost-effective, it has the serious disadvantage that the regulating characteristic is unfavourable. The object of the invention is therefore to provide a cost-effective air throttling device for forced draught burners, especially for multistage burners, which establishes an as far as possible linear connection between the regulating path of the regulating member and the volumetric flow. According to the invention, this object is achieved in that the flap, which is arranged in front of the air inflow nozzle, is constructed as a throttle plate (5) which is capable of moving in translatory fashion with respect to the inflow nozzle (4), in which case the through-flow area of the air gap existing between the outer contour (10) of the throttle plate (5) and the outer contour (11) of the inflow nozzle (4) changes approximately proportionally as a function of the adjusting path of the throttle plate (5). IMAGE