Burner system for a furnace

Abstract

A burner system for a furnace. The system may have a wedged or other shaped burner box. An air-fuel mixer may be attached to a smaller end of the burner box at about a right angle relative to a direction of a gas and air mixture leaving the larger box end. A burner head may be attached to the larger end of the box. The burner head may be sufficient for numerous heater sections of a heat exchanger. A spacer and an orifice shield may be situated between the burner head and heat exchanger. A fan may pull in the gas and air mixture from the mixer, through the box and the burner head. The mixture may be ignited into a flame which is pulled into the heat exchanger. Some of the flue gas from the exchanger exhaust may be recirculated by being added with air to the mixer.

1 . A furnace burner system comprising:
 an air-fuel mixer;   a burner box coupled to the mixer;   a burner head coupled to a first open end of the burner box;   a spacer coupled to an output side of the burner head;   an orifice shield coupled to an output side of the spacer and an input side of a heat exchanger; and   an igniter situated between the burner head and the orifice shield; and   wherein the heat exchanger comprises a tube or clamshell structure.   
     
     
         2 . The system of  claim 1 , wherein:
 the burner box is funnel-shaped and has a wider portion in a direction toward the burner head and a narrower portion in a direction toward the mixer; and   a direction of a gas and air mixture input to the burner box is different from a direction of the gas and air mixture out from the burner box.   
     
     
         3 . The system of  claim 2 , wherein the mixer comprises an input to receive a portion of exhaust gas from the heat exchanger for recirculation. 
     
     
         4 . The system of  claim 1 , wherein the mixer comprises:
 a gas orifice; and   an air orifice; and   wherein the gas and air orifices are sized to minimize combustion CO2 for decreasing NOx emissions.   
     
     
         5 . The system of  claim 1 , wherein the burner head comprises a FeCrAl alloy fiber mat. 
     
     
         6 . The system of  claim 1 , further comprising a blower to provide a below atmospheric pressure in a plurality of sections of the tube or clamshell structure of the heat exchanger to draw the gas and air mixture into the burner box and pull a flame at the burner head through the orifice shield into the plurality of sections. 
     
     
         7 . A method for achieving a low-emissions furnace, comprising:
 drawing an air and gas mixture into a manifold;   drawing the air and gas mixture from the manifold through a burner head and a spacer;   igniting the air and gas mixture in the spacer with an igniter into a flame; and   drawing the flame from the spacer through a plurality of sections of a heat exchanger and drawing exhaust gases out from the heat exchanger.   
     
     
         8 . The method of  claim 7 , wherein:
 the drawing of the air and gas mixture, the flame, and exhaust gases is performed with an air mover; and   a portion of the exhaust gases is re-circulated into the air and gas mixture.   
     
     
         9 . The method of  claim 7 , wherein:
 an air-fuel mixer is coupled to the manifold; and   the air and gas mixture is drawn into the manifold from the mixer.   
     
     
         10 . The method of  claim 7 , wherein the flame is kept on a side of the burner head towards the heat exchanger when being drawn from the spacer into the plurality of sections. 
     
     
         11 . The method of  claim 10  wherein a section is a tube. 
     
     
         12 . The method of  claim 7  wherein:
 a temperature sensor is situated in the spacer; and 
 a temperature indication from the temperature sensor provides a condition of combustion of the mixture and/or a condition of the air and gas mixture. 
 
     
     
         13 . The method of  claim 9 , wherein:
 the manifold comprises an enclosure wall from the mixer to the burner head;   the manifold comprises an input at the mixer and an output at the burner head; and   an area of an opening of the output is greater than an area of an opening of the input; and   a cross-section area virtually perpendicular to a line between the intake and the output increases proportionally relative to a distance from the intake area towards the output of the manifold.   
     
     
         14 . The method of  claim 13 , wherein a direction of the air and gas mixture coming in through the input of the manifold is at an angle between 60 and 120 degrees relative to a direction of the air and gas mixture going through the output of the manifold. 
     
     
         15 . A burner assembly comprising:
 a manifold box having an input port and output port;   an air-fuel mixer coupled to the input port;   a burner head coupled to the output port;   a spacer coupled to the burner head; and   a one-to-multiple flame conformer coupled to the spacer.   
     
     
         16 . The assembly of  claim 15 , wherein:
 the one-to-multiple flame conformer comprises a plate having a plurality of openings, coupled to the spacer; and   each opening of the plurality of openings is aligned with and coupled to a first end of a section of a plurality of sections of a heat exchanger.   
     
     
         17 . The assembly of  claim 16 , further comprising an air mover having an input connected to second ends of the plurality of sections. 
     
     
         18 . The assembly of  claim 17 , wherein:
 an air tube is coupled to an intake of the mixer and to an air supply;   an output tube is coupled to the intake of the mixer and an output of the air mover;   the output tube comprises a flow limiting orifice situated in series with the output tube; and   the intake of the mixer is coupled to a fuel valve and fuel supply port.   
     
     
         19 . The assembly of  claim 15 , wherein a direction of flow at the input port is different than a direction of flow at the output port. 
     
     
         20 . The assembly of  claim 15 , wherein the manifold box has two or more slanted sides opening further away relative to one another, from the input end towards the output end in a form of a funnel. 
     
     
         21 . The system of  claim 1 , wherein the burner head comprises one or more layers selected from a group consisting of a mat, a weave and a knit. 
     
     
         22 . The system of  claim 21 , wherein the one or more layers comprise fibers, strands and/or wires. 
     
     
         23 . The system of  claim 21 , wherein the one or more layers comprise one or more materials selected from a group consisting of a FeCrAl alloy, Kanthal™, Fecralloy™, and a non-metal. 
     
     
         24 . The system of  claim 23 , wherein the one or more materials withstand temperatures greater than 1800 degrees F.