Burner provided with means against the overheating of the burner head

Abstract

A burner ( 2; 2 a ; 11; 25; 31; 34 ), comprising a burner body ( 12; 26; 32; 35 ), wherein a mixture of fuel and air can be introduced, and a burner head ( 14; 27; 32; 35 a ; 41 ), wherein a plurality of openings ( 15; 28; 40; 44 ) is provided, thr ough which said mixture can flow, is associated with shield means ( 3; 16; 29: 33; 36; 42 ) shielding said burner head ( 14; 27; 32; 35 a ; 41 ) suitable for limiting the maximum temperature that said burner head ( 14; 27; 32; 35 a ; 41 ) can reach during working of the burner ( 2; 2 a ; 11; 25; 31; 34 ).

1 . Burner ( 2 ;  2   a ;  11 ;  25 ;  31 ;  34 ), comprising a burner body ( 12 ;  26 ;  32 ;  35 ) wherein a mixture of fuel and air can be introduced, a burner head ( 14 ;  27 ;  32 ;  35   a ;  41 ) wherein a plurality of openings ( 15 ;  28 ;  40 ;  44 ) is provided, through which said mixture can flow, characterized in that it is associated with shield means ( 3 ;  16 ;  29 ;  33 ;  36 ;  42 ) shielding said burner head ( 14 ;  27 ;  32 ;  35 ;  41 ) suitable for limiting the maximum temperature that said burner head ( 14 ;  27 ;  32 ;  35   a ;  41 ) can reach during working of the burner ( 2 ;  2   a ;  11 ;  25 ;  31 ;  34 ):  
     
     
         2 . Burner according to  claim 1 , wherein said shield means ( 3 ) is so positioned as to shield said burner head from the heat irradiation originating from walls ( 1 ) of a combustion chamber in which said burner ( 2 ;  2   a ) can be inserted.  
     
     
         3 . Burner according to one of the preceding claims, wherein said shield means ( 3 ) is positioned below the ignition plane of flames produced by combustion of said mixture.  
     
     
         4 . Burner according to one of the preceding claims, wherein said shield means comprises at least one flat element ( 3 ).  
     
     
         5 . Burner according to  claim 4 , wherein said at least one flat element ( 3 ) has a major dimension oriented in a direction substantially parallel to a longitudinal axis of said burner ( 2 ;  2   a ).  
     
     
         6 . Burner according to  claim 4 , or  5 , wherein said at least one flat element ( 3 ) is supported in an isostatic manner.  
     
     
         7 . Burner according to  claim 6 , wherein said at least one flat element ( 3 ) is rigidly supported at a first end by a structure element of said combustion chamber.  
     
     
         8 . Burner according to  claim 6 , or  7 , wherein said at least one flat element ( 3 ) is supported, at a second end opposite to said first end, by another structure element of said combustion chamber, so as to be slidable in a direction parallel to said major dimension.  
     
     
         9 . Burner according to one of  claims 4  to  8 , wherein said at least one flat element ( 3 ) is provided with at least one stiffening rib ( 4 ) extending in a direction substantially parallel to said major dimension.  
     
     
         10 . Burner according to one of  claims 4  to  9 , wherein said at least one flat element ( 3 ) is provided with through openings ( 52 ).  
     
     
         11 . Burner according to  claim 10 , wherein said through openings ( 52 ) are associated to further shield means ( 52 ;  53 ).  
     
     
         12 . Burner according to one of the preceding claims, wherein said shield means ( 3 ) is made of a material resisting to high temperatures and to remarkable thermal stresses.  
     
     
         13 . Burner according to one of the preceding claims, wherein said shield means ( 3 ) is made of a material having high bending and/or torsional stability.  
     
     
         14 . Burner according to one of the preceding claims, wherein said shield means ( 3 ) is made of a material chosen from a group comprising refractory steel, refractory ceramic material and cermet.  
     
     
         15 . Burner according to  claim 1 , wherein said shield means comprises a further burner head ( 16 ;  29 ;  33 ;  36 ;  42 ), which can be superimposed to said burner head ( 14 ;  27 ;  32 ;  35   a ;  41 ) and fixed thereto so as to be capable of sliding with respect to said burner head ( 14 ;  27 ;  32 ;  35   a ;  41 ) as an effect of thermal expansions.  
     
     
         16 . Burner according to  claim 15 , wherein said further burner head ( 16 ;  29 ;  33 ;  36 ;  42 ) comprises a plurality of further openings ( 17 ;  30 ;  37 ;  45 ) through which said mixture can flow.  
     
     
         17 . Burner according to  claim 15 , or  16 , wherein said further openings ( 17 ;  30 ;  37 ;  45 ) can be aligned with said openings ( 15 ;  28 ;  40 ;  44 ).  
     
     
         18 . Burner according to one of  claims 15  to  17 , wherein said further burner head ( 16 ;  29 ;  33 ;  36 ;  42 ) is connected to said burner head ( 14 ;  27 ;  32 ;  35   a ;  41 ) through connecting means (S;  12 ;  19   a ;  26   a ;  28 ;  29 ;  33 ) substantially removable.  
     
     
         19 . Burner according to one of  claims 15  to  18 , wherein said burner head ( 14 ) is provided with first guide means ( 19 ) for said further burner head ( 16 ), said first guide means ( 19 ) being suitable for coupling with second guide means ( 20 ,  21 ) provided in said further burner head ( 16 ).  
     
     
         20 . Burner according to  claim 19 , wherein said first guide means comprises pin means ( 19 ).  
     
     
         21 . Burner according to  claim 19 , or  20 , wherein said second guide means comprises slot means ( 20 ,  21 ).  
     
     
         22 . Burner according to one of  claims 18  to  21 , wherein said connecting means comprises “U” shaped small plate means ( 22 ).  
     
     
         23 . Burner according to  claim 22 , wherein said “U” shaped small plate means ( 22 ) is insertable in a first opening ( 23 ) provided in said burner head ( 14 ) and in a respective second opening ( 24 ) provided in said further burner head ( 16 ).  
     
     
         24 . Burner according to one of  claims 18  to  21 , wherein said connecting means comprises bracket means ( 38 ).  
     
     
         25 . Burner according to  claim 24 , wherein said bracket means ( 38 ) is fixed in a substantially removable manner to said burner head ( 35   a ), near the ends of said further burner head ( 36 ).  
     
     
         26 . Burner according to one of  claims 15  to  25 , wherein said further burner head ( 36 ) is provided with ribs ( 46 ,  47 ,  48 ).  
     
     
         27 . Burner according to  claim 26 , wherein said ribs ( 46 ,  47 ,  48 ) extend transversely to said further burner head ( 16 ) and in a direction substantially perpendicular to the surface of said further burner head ( 16 ).  
     
     
         28 . Burner according to  claim 26 , or  27 , wherein said ribs ( 46 ,  47 ,  48 ) comprise a first rib ( 46 ) arranged at a first end of said further burner head ( 16 ) and a second rib ( 47 ) arranged at a second end of said further burner head ( 16 ).  
     
     
         29 . Burner according to one of  claims 26  to  28 , wherein said ribs ( 46 ,  47 ,  48 ) comprise a further rib ( 48 ) arranged in a substantially central position of said further burner head ( 16 ).  
     
     
         30 . Burner according to one of  claims 18  to  21 , wherein said connecting means comprises strap means ( 39 ).  
     
     
         31 . Burner according to  claim 30 , wherein said strap means ( 39 ) is fixed in a substantially removable manner to said head, near the ends of said further burner head ( 36 ).  
     
     
         32 . Burner according to one of  claims 18  to  21 , wherein said burner head is a portion of a first tubular body ( 32 ) and said further burner head is a portion of a second tubular body ( 33 ), substantially externally concentric to said first tubular body ( 32 ).  
     
     
         33 . Burner according to one of  claims 18  to  21 , wherein said burner head ( 41 ) and said further burner head ( 42 ) are substantially flat.  
     
     
         34 . Burner according to  claim 33 , wherein said burner head ( 41 ) and said further burner head ( 42 ) are mutually connected through connecting elements ( 43 ) arranged along a couple of respective opposite sides of said burner head ( 41 ) and of said further burner head ( 42 ).  
     
     
         35 . Burner according to  claim 34 , wherein said connecting elements ( 43 ) have a “C” shaped cross section.  
     
     
         36 . Burner according to  claim 34 , or  35 , wherein said connecting elements ( 4 - 3 ) are connected in a removable manner to the burner body.  
     
     
         37 . Burner according to one of  claims 16  to  36 , wherein the dimensions of said openings ( 15 ;  28 ;  40 ;  44 ) and of said further openings ( 17 ;  30 ;  37 ;  45 ) and the position of said further burner head ( 16 ;  29 ;  33 ;  36 ;  42 ) with respect to said burner head ( 14 ;  27 ;  32 ;  35   a ;  41 ) are so chosen that, in full power working conditions, the further openings ( 17 ;  30 ;  37 ;  45 ) and the openings ( 15 ;  28 ;  40 ;  44 ) are mutually aligned so as to define the largest flowing section for said mixture.  
     
     
         38 . Burner according to one of  claims 16  to  37 , wherein the dimensions of said openings ( 15 ;  28 ;  40 ;  44 ) and of said further openings ( 17 ;  30 ;  37 ;  45 ) and the position of said further burner head ( 16 ;  29 ;  33 ;  36 ;  42 ) with respect to said burner head ( 14 ;  27 ;  32 ;  35   a ;  41 ) are so chosen that, in minimum power or near minimum power working conditions, the flowing section for said mixture of air and fuel is throttled.  
     
     
         39 . Burner according to one of  claims 16  to  36 , wherein the dimensions of said openings ( 15 ;  28 ;  40 ;  44 ) and of said further openings ( 17 ;  30 ;  37 ;  45 ) and the position of said further burner head ( 16 ;  29 ;  33 ;  36 ;  42 ) with respect to said burner head ( 14 ;  27 ;  32 ;  35   a ;  41 ) are so chosen that the overall flowing section for said mixture of air and fuel is substantially constant in any normal working conditions.