North American Manufacturing Company, Inc.

Fives North American Combustion, Inc.

Dennis E Quinn

Thomas F Robertson

Todd A Miller

David S Hausen

Ashley N Graybill

An apparatus includes first and second mixer tubes. The first mixer tube contains a first gas flow passage having an inlet communicating with the source of fuel gas and an outlet to a combustion chamber. The second mixer tube contains a second gas flow passage having an inlet communicating with the source of combustion air and an outlet to the combustion chamber. The apparatus further includes premix control means for forming fuel gas-combustion air premix in the second passage by directing fuel gas from the first passage into the second passage, and for alternatively forming fuel gas-combustion air premix in the first passage by directing combustion air from the second passage into the first passage.

Apparatus and method for variable mode mixing of combustion reactants

A burner fires into a radiant tube to provide a downstream flow of combustion products within the radiant tube. Staged fuel is injected upstream into the radiant tube. A recirculation conduit inside the radiant tube receives the staged fuel along with combustion products that are inspirated into the recirculation conduit by the staged fuel. The recirculation conduit has an outlet for discharging a mixture of the inspirated combustion products and staged fuel into the downstream flow of combustion products.

Radiant tube with recirculation

A method and apparatus provide combustion in a radiant tube in first, second and third stages, with flue gas recirculation that begins at the second stage.

Method and apparatus for radiant tube combustion

A treatment system and method is disclosed for heat treating aggregate, for example, an aggregate dryer of the type which uses a burner and rotating drum for veiling aggregate into a thermal flow path. The invention provides a plurality of mixers which safely mix fuel and oxidant into a premix which is delivered to a reaction chamber The premix is combusted and recirculated within the reaction chamber to insure uniform and complete combustion, resulting in lower emissions of pollutants such as carbon monoxide, volatile organic compounds, and nitrogen oxides and also lower combustion roar. This uniform and complete combustion results in a more uniform thermal profile within the rotating drum, resulting a greater throughput of processed aggregate and a more efficient consumption of energy. The invention also includes a 'tunability' feature for varying the delivery of fuel to the burner in order to avoid resonant vibration produced by a matching of the combustion frequencies with the natural frequency of the treatment system.

Method and apparatus for aggregate treatment

A burner is disclosed having a burner chamber with heavily insulated heat retaining walls and a series of off-center mixers located at one end thereof. A uniform concentration gas/air mixture to 50% additional fuel above the lean flammability limit coming from the mixer tubes is ignited in the burner chamber due to the recirculation of combusting gas and air back to the end of the burner chamber above auto the ignition temperature for the mixture. The particular mixture disclosed utilizes 0.55-0.7 equivalence ratio. With the present burner, oxidant and fuel are respectively supplied to each mixer by respective common oxidant and fuel plenums. In this way, fuel and oxidant are mixed near the point of combustion, enhancing safety and permitting the construction of larger burners.

Ultra low NOX burner

A burner is disclosed having a burner chamber with heavily insulated heat retaining walls and a series of off center mixer tubes located at one end thereof. A uniform concentration gas/air mixture to 50% additional fuel above the lean flammability limit coming from the mixer tubes is ignited in the burner chamber due to the recirculation of combusting gas and air back to the end of the burner chamber above auto the ignition temperature for the mixture. The particular mixture disclosed utilizes 0.55-0.7 equivalence ratio.

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Hinckley, OH, United States of America

Dennis E Quinn