Radiant tube with recirculation
AssigneeFives North American Combustion, Inc.
InventorDennis E. Quinn
Life of this patent
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Abstract
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.
Claims35
A method comprising:
- providing a downstream flow of combustion products in a radiant tube;
- injecting staged fuel into the radiant tube;
- and
- recirculating gaseous contents of the radiant tube by:
- withdrawing combustion products from the downstream flow;
- forming a mixture of the staged fuel and withdrawn combustion products;
- transporting the mixture upstream relative to the downstream flow along a flow path separate from the downstream flow;
- and
- discharging the transported mixture into the downstream flow.
A method comprising:
- providing a downstream flow of combustion products in a radiant tube;
- injecting fuel into the radiant tube in a direction upstream relative to the downstream flow;
- and
- recirculating gaseous contents of the radiant tube by:
- withdrawing combustion products from the downstream flow;
- forming a mixture of the injected fuel and withdrawn combustion products;
- transporting the mixture upstream relative to the downstream flow along a flow path separate from the downstream flow;
- and
- discharging the transported mixture into the downstream flow.
An apparatus comprising:
- a radiant tube;
- a burner configured to fire into the radiant tube;
- a recirculation conduit having an inlet within the radiant tube and an outlet within the radiant tube at location between the inlet and the burner;
- and
- an injector configured to inject staged fuel that inspirates gaseous contents of the radiant tube into the inlet of the recirculation conduit.
An apparatus comprising:
- a radiant tube extending across a process chamber in a straight line from one furnace wall to another furnace wall, the radiant tube having an upstream end and a downstream end;
- means for providing a flow of combustion air downstream through the radiant tube;
- a recirculation conduit having an inlet within the radiant tube and an outlet within the radiant tube at location upstream of the inlet;
- and
- an injector configured to inject fuel that inspirates gaseous contents of the radiant tube into the inlet of the recirculation conduit.
An apparatus comprising:
- a radiant tube;
- a burner configured to fire into the radiant tube in a direction downstream from the burner and thereby to generate a downstream flow of combustion products within the radiant tube;
- an injector configured to inject staged fuel into the radiant tube in a direction upstream relative to the downstream flow of combustion products;
- and
- a recirculation conduit contained within the radiant tube, the recirculation conduit having an inlet aligned with the injector to receive the staged fuel along with combustion products inspirated into the recirculation conduit by the staged fuel, and having an outlet configured to discharge a mixture of the inspirated combustion products and staged fuel into the downstream flow of combustion products at a location between the inlet and the burner.
Dependencies are inferred from the claim text.