Patent ID: 6925809

Claim:
Apparatus for premixing fuel and air to provide a fuel/air mixture, the apparatus comprising: a fuel valve for controlling a flow of fuel; an air valve for controlling a flow of air in accordance with the flow of fuel to provide a controlled fuel/air ratio; a mixing tube configured for receiving and mixing the fuel and air, the mixing tube having an entrance, an axis, and an exit for discharging a fuel/air mixture; and a mixture valve associated with said mixing tube exit and separate from the fuel valve and the air valve, the mixture valve including inner and outer mixture valve members that together define an asymmetric exit flow area; wherein the defined exit flow area includes at least two segmented, substantially opposed, mixture flow-directing area portions with respect to an angular position about the mixing tube axis; wherein said mixture valve is configured to asymmetrically flow said fuel/air mixture predominantly through said mixture flow directing area portions; and wherein at least one of said inner and outer mixture valve members is movable relative to the other of said valve members to selectively vary the defined exit flow area with respect to time.