End apparatus comprising a progressive combustion head for low nox emissions and burner comprising this end apparatus

Abstract

An end apparatus ( 1 ) for a burner configured to generate a flame, comprising a supply conduit ( 5 ) for supplying a comburent and a combustion head ( 2 ) at least partially inserted into the supply conduit ( 5 ) so as to define a passage gap ( 9 ) between the combustion head ( 2 ) and the supply conduit ( 5 ) for a flow of comburent (C). In particular, the combustion head ( 2 ) comprises a plurality of outer openings ( 11 ), arranged outside the passage gap ( 9 ), configured to emit a first flow of fuel (F 1 ) outside the flow of comburent and a plurality of inner openings ( 12 ) arranged at and/or inside the passage gap ( 9 ) adapted to introduce a second flow of fuel (F 2 ′, F 2 ″) inside the flow of a comburent.

1 . An end apparatus ( 1 ) for a burner configured to generate a flame, comprising:
 a combustion head ( 2 ) connectable to supply means for supplying a fuel and having at least one inlet opening ( 3 ), adapted to enable a fuel to enter, and a plurality of outlet openings ( 4 ), adapted to enable an outflow of fuel;   a comburent supply conduit ( 5 ) configured to convey a comburent to said combustion head ( 2 ) and extending between a comburent introduction opening ( 6 ) and an emission opening ( 7 ) along a main extension direction (X);   wherein said combustion head ( 2 ) is at least partially inserted into said supply conduit ( 5 ), at the emission opening ( 7 ), so as to define a passage gap ( 9 ) between said combustion head ( 2 ) and said supply conduit ( 5 ) for a flow of comburent (C);   characterized in that said combustion head ( 2 ) comprises:   a plurality of outer openings ( 11 ) arranged outside said passage gap ( 9 ) according to a direction that is radial to said main extension direction (X) and configured to emit a first flow of fuel (F 1 ) outside said flow of a comburent; and   a plurality of inner openings ( 12 ) arranged at and/or inside said passage gap ( 9 ) according to a direction that is radial to said main extension direction (X), said inner openings ( 12 ) being adapted to introduce a second flow of fuel (F 2 ′, F 2 ″) inside said flow of a comburent.   
     
     
         2 . The apparatus according to  claim 1 , wherein said combustion head ( 2 ) comprises a central body ( 13 ) at least partially inserted into said supply conduit ( 5 ) and extending between a first end ( 14 ), defining said inlet opening ( 3 ), and a second end ( 15 ) along an extension direction (E); said second end ( 15 ) defining with said supply conduit ( 5 ) at least partially said passage gap ( 9 ). 
     
     
         3 . The apparatus according to  claim 2 , wherein said central body ( 13 ) has a substantially axially symmetric extension relative to said extension direction (E). 
     
     
         4 . The apparatus according to  claim 2 , wherein said extension direction (E) is parallel to, preferably coincident with, said main extension direction (X). 
     
     
         5 . The apparatus according to  claim 2 , wherein said central body ( 13 ) has a housing ( 16 ) adapted to receive a reversibly inserted further supply conduit ( 17 ) for supplying a fuel, said housing ( 16 ) extending between said first end ( 14 ) and said second end ( 15 ) parallel to said extension direction (E). 
     
     
         6 . The apparatus according to  claim 2 , comprising at least one switch-on conduit ( 18 ) in fluid communication with said supply conduit ( 5 ) and passing through said central body ( 13 ) to convey a quantity of comburent to said second end ( 15 ) of said central body ( 13 ). 
     
     
         7 . The apparatus according to  claim 2 , wherein said second end ( 15 ) has a convergent portion ( 19 ), preferably truncated conically shaped, along said extension direction (E) and defining with said supply conduit ( 5 ) at least partially said passage gap ( 9 ). 
     
     
         8 . The apparatus according to  claim 7 , wherein said convergent portion ( 19 ) has a plurality of outflow holes ( 20   a ) adapted to introduce at least partially said second flow of fuel (F 2 ′) inside said flow of a comburent, said plurality of outflow holes ( 20   a ) defining at least partially said inner openings ( 12 ). 
     
     
         9 . The apparatus according to  claim 7 , wherein said second end ( 15 ) has at least one divergent portion ( 21 ) along said extension direction said divergent portion ( 21 ) being arranged at least partially inside said convergent portion ( 19 ). 
     
     
         10 . The apparatus according to  claim 9 , wherein said divergent portion ( 21 ) has a plurality of outflow holes ( 20   b ) adapted to introduce at least partially said second flow of fuel (F 2 ′) inside said flow of a comburent, said plurality of outflow holes ( 20   b ) defining at least partially said inner openings ( 12 ). 
     
     
         11 . The apparatus according to  claim 10 , wherein said second end ( 15 ) has at least one retaining surface ( 22 ) adapted to connect said divergent portion ( 21 ) and said convergent portion ( 19 ). 
     
     
         12 . The apparatus according to  claim 11 , wherein said retaining surface ( 22 ) is perpendicular to said extension direction (E). 
     
     
         13 . The apparatus according to  claim 11 , wherein said retaining surface ( 22 ) is at least partially lobe-shaped. 
     
     
         14 . The apparatus according to  claim 2 , wherein said combustion head ( 2 ) comprises a plurality of outflow conduits ( 23 ) branching off from said first end ( 14 ) of said central body ( 13 ) and extending at least partially along a direction parallel to said extension direction (E), said plurality of outflow conduits ( 23 ) defining at least partially said plurality of outer openings ( 11 ) and/or said plurality of inner openings ( 12 ). 
     
     
         15 . The apparatus according to  claim 1 , wherein said combustion head ( 2 ) comprises at least one inner nozzle ( 24 ) arranged inside said supply conduit ( 5 ) according to a direction that is radial to said main extension direction (X), said inner nozzle ( 24 ) defining at least partially said plurality of inner openings ( 12 ). 
     
     
         16 . The apparatus according to  claim 15  as appended to one or more of  claims 2-14 , wherein said at least one inner nozzle ( 24 ) is interposed between said central body ( 13 ) and said supply conduit ( 5 ). 
     
     
         17 . The apparatus according to  claim 15 , wherein said at least one inner nozzle ( 24 ) has an extension axis tilted relative to said extension direction (E). 
     
     
         18 . The apparatus according to  claim 15 , wherein said combustion head ( 2 ) comprises a plurality of inner nozzles ( 24 ) having an extension transverse to said extension direction (E) so that said second flow is at least partially convergent along said extension direction (E). 
     
     
         19 . The apparatus according to  claim 1 , wherein said combustion head ( 2 ) comprises a plurality of outer nozzles ( 25 ) in fluid communication with said inlet opening ( 3 ) and arranged outside said supply conduit ( 5 ) according to a direction that is radial to said main extension direction (X), said outer nozzles ( 25 ) defining at least partially said plurality of outer openings ( 11 ). 
     
     
         20 . The apparatus according to  claim 19 , wherein said outer nozzles ( 25 ) has an extension that is substantially parallel to said main extension direction (X) so as to emit said first flow of fuel (F 1 ) outside said flow of a comburent. 
     
     
         21 . The apparatus according to  claim 19 , wherein said outer nozzles ( 25 ) are arranged perimetrically to said supply conduit ( 5 ) and near said emission opening ( 7 ). 
     
     
         22 . The apparatus according to  claim 1 , wherein said combustion head ( 2 ) is reversibly moveable relative to said supply conduit ( 5 ) along a movement direction that is parallel to, preferably coincident with, said main extension direction (X). 
     
     
         23 . The apparatus according to  claim 1 , wherein said supply conduit ( 5 ) has an end portion ( 10 ) defining a convergent profile near said emission opening ( 7 ). 
     
     
         24 . The apparatus according to  claim 1 , comprising flame ignition means ( 8 ) adapted to promote combustion between said fuel and said comburent. 
     
     
         25 . The apparatus according to  claim 1 , wherein said combustion head ( 2 ) has a passage conduit ( 1000 ) defining an inlet ( 1001 ) and an outlet ( 1002 ) through which the flow of comburent (C) can flow at least partially. 
     
     
         26 . A burner comprising:
 an end apparatus ( 1 ) according to  claim 1 ;   suction means ( 102 ) configured to suck at least an amount of comburent from an environment outside said burner and to move said at least an amount of comburent from said second introduction opening ( 6 ) to said second emission opening ( 7 ).