DUAL FUEL, STAGED AIR, LOW NOx GAS BURNER

Abstract

A dual fuel, staged air, low NOx gas burner. The burner assembly includes an elongated air inlet device having a first open end for introduction of air. A first fuel source conduit delivers a first fuel into the air inlet device to a plurality of axially aligned fuel fingers wherein the fingers are spaced in an annular pattern within the air inlet device. A second fuel source conduit delivers a second fuel into the air inlet device to a castellation arm assembly having a plurality of radially extending castellation arms with troughs therein, wherein the axially aligned fuel fingers are juxtaposed between the radially extending castellation arms.

What is claimed is: 
     
         1 . A dual fuel, staged air, low NOx gas burner, which burner comprises:
 an elongated air inlet device having a first open end for introduction of air;   a first fuel source conduit delivering a first fuel into said air inlet device;   at least one fuel finger in fluid communication with said first fuel source conduit, said fuel finger within said elongated air inlet device;   a second fuel source conduit delivering a second fuel into said elongated air inlet device; and   a castellation arm assembly in fluid communication with said second fuel source conduit, said castellation arm assembly having a plurality of radially extending castellation arms with troughs therein.   
     
     
         2 . A dual fuel, staged air, low NOx gas burner as set forth in  claim 1  wherein said at least one fuel finger includes a plurality of axially aligned fuel fingers spaced in an annular pattern. 
     
     
         3 . A dual fuel, staged air, low NOx gas burner as set forth in  claim 2  wherein said plurality of axially aligned fuel fingers are in fluid communication with said first fuel source conduit through a ring manifold to distribute said first fuel from said first fuel source conduit to said plurality of axially aligned fuel fingers. 
     
     
         4 . A dual fuel, staged air, low NOx gas burner as set forth in  claim 2  wherein said plurality of axially aligned fingers are juxtaposed between said plurality of radially extending castellation arms. 
     
     
         5 . A dual fuel, staged air, low NOx gas burner as set forth in  claim 2  wherein each of said plurality of axially aligned fuel fingers terminates in a nozzle having a pair of ports. 
     
     
         6 . A dual fuel, staged air, low NOx gas burner as set forth in  claim 2  wherein said elongated air inlet device is tubular with a center axis and wherein said plurality of axially aligned fuel fingers are arranged in said annular pattern around a center axis coaxial with said air inlet device center axis. 
     
     
         7 . A dual fuel, staged air, low NOx gas burner as set forth in  claim 2  wherein said air inlet device has a second end opposed to said first open end. 
     
     
         8 . A dual fuel, staged air, low NOx gas burner as set forth in  claim 7  wherein said plurality of axially aligned fuel fingers terminate within said air inlet device spaced from said second end. 
     
     
         9 . A dual fuel, staged air, low NOx gas burner as set forth in  claim 2  wherein said plurality of radially extending castellation arms terminate within said air inlet device between said second end and said termination of said axially aligned fuel fingers. 
     
     
         10 . A dual fuel, staged air, low NOx gas burner as set forth in  claim 1  including a plurality of staged air conduits, each of said plurality of staged air conduits having a first open end in said air inlet device and a second open end radially outward from said first end. 
     
     
         11 . A dual fuel, staged air, low NOx gas burner as set forth in  claim 1  wherein said second fuel source conduit includes a nozzle in advance of said castellation arm assembly. 
     
     
         12 . A dual fuel, staged air, low NOx gas burner as set forth in  claim 2  wherein said plurality of axially aligned fuel fingers are equal in number to said plurality of radially extending castellation arms. 
     
     
         13 . A dual fuel, staged air, low NOx gas burner as set forth in  claim 2  wherein said first fuel is gaseous. 
     
     
         14 . A dual fuel, staged air, low NOx gas burner as set forth in  claim 1  wherein said second fuel is gaseous. 
     
     
         15 . A dual fuel, staged air, low NOx gas burner, which burner comprises:
 an elongated tubular air inlet device having a first open end for introduction of air and an opposed second end;   a first fuel source conduit delivering a first fuel into said air inlet device;   a plurality of axially aligned fuel fingers in fluid communication with said first fuel source conduit through a ring manifold, said axially aligned fuel fingers arranged in an annular pattern within said elongated air inlet device wherein said axially aligned fuel fingers terminate with said air inlet device spaced from said second end;   a second fuel source conduit delivering a second fuel into said air inlet device; and   a castellation arm assembly in fluid communication with said second fuel source conduit, said castellation arm assembly having a plurality of radially extending castellation arms with troughs therein, wherein said plurality of axially aligned fuel fingers are juxtaposed between said plurality of radially extending castellation arms.   
     
     
         16 . A process to produce a low NOx flame from a gas burner, which process comprises the steps of:
 introducing combustion air into said air inlet device;   introducing a first fuel source into an air inlet device through at least one fuel finger within said air inlet device to mix said first fuel source with said combustion air in a controlled manner; and   introducing a second fuel source into said air inlet device through a castellation arm assembly having a plurality of radially extending castellation arms with troughs therein, thereby mixing second fuel with combustion air.   
     
     
         17 . A process as set forth in  claim 16  wherein said at least one fuel finger includes a plurality of axially aligned fuel fingers spaced in an annular pattern. 
     
     
         18 . A process as set forth in  claim 16  including the additional step of introducing combustion air from within said air inlet device through a plurality of staged air conduits, wherein each of said plurality of staged air conduits has a first open end in said air inlet device and a second open end radially outward from said first open end. 
     
     
         19 . A process as set forth in  claim 17  wherein said first fuel source is distributed to said plurality of axially aligned fuel fingers through said first fuel source conduit to a ring manifold and thereafter to said plurality of axially aligned fuel fingers. 
     
     
         20 . A process as set forth in  claim 17  wherein said plurality of axially aligned fuel fingers are juxtaposed between said plurality of radially extending castellation arms.