Burner, specifically a premix gas burner

Abstract

What is described is a burner, specifically for gas fuels with premixing, comprising a burner body designed to be housed in a combustion chamber of a heating apparatus, the burner body being provided with a burner head on which an air and gas mixture supplied to the combustion chamber is burnt, in which the burner head has a surface profile in the form of a dome-shaped spherical segment, the height of the dome being less than half of the diameter of the sphere to which the segment belongs.

1 . A burner, specifically for gas fuels with premixing, comprising a burner body ( 2 ) housed in a combustion chamber ( 4 ) of a heating apparatus, said burner body ( 2 ) comprising a burner head ( 3 ) on which an air and gas mixture supplied to the combustion chamber ( 4 ) is burnt, wherein said burner head ( 3 ) has a surface profile ( 3   a ) in the form of a dome-shaped spherical segment, a height (H) of said dome being less than half of a diameter (D) of the sphere to which said segment belongs. 
     
     
         2 . A burner according to  claim 1 , in which the height (H) of said dome-shaped spherical segment is less than half a base diameter (D 1 ) of said dome. 
     
     
         3 . A burner according to  claim 1 , in which said burner head ( 3 ) is made from metallic material. 
     
     
         4 . A burner according to  claim 3 , in which said burner head ( 3 ) is made from perforated sheet metal. 
     
     
         5 . A burner according to  claim 1 , in which said burner head ( 3 ) is made in the form of a metallic grid or mesh. 
     
     
         6 . A burner according to  claim 1 , in which said burner head ( 3 ) is made from fibre. 
     
     
         7 . A burner according to  claim 1 , comprising a fastener for fastening the burner head ( 3 ) to a support flange ( 8 ) of said head, said fastener comprising at least one seat ( 16 ) on said flange ( 8 ) shaped in the form of a pocket and at least one portion of a perimetric base edge ( 10 ) of the dome, said seat ( 16 ) being engageable by said portion of dome with the possibility of limited relative sliding, thus locking the head ( 3 ) to the flange ( 8 ) while allowing the free expansion of the head ( 3 ), particularly its thermal expansion, relative to the seat ( 16 ). 
     
     
         8 . A burner according to  claim 7 , in which said pocket-shaped seat ( 16 ) extends circumferentially along the flange ( 8 ) in a continuous way without any interruption. 
     
     
         9 . A burner according to  claim 7 , in which said seat ( 16 ) is formed jointly by two corresponding distinct and separate portions ( 8   a ,  8   b ) of said flange ( 8 ) which can be fastened together while maintaining a distance between them, in such a way that the pocket of said seat ( 16 ) is formed as a result of their locking together. 
     
     
         10 . A burner according to  claim 7 , in which said seat ( 16 ) has, in a diametric cross section, a predominant longitudinal extension in a direction which cuts the principal axis of the dome. 
     
     
         11 . A burner according to  claim 10 , in which the depth of said pocket-shaped seat ( 16 ) is chosen so as to allow the edge ( 10 ) of the head ( 3 ) engaged in said seat ( 16 ) to slide freely, at least along the said direction of longitudinal extension. 
     
     
         12 . A burner according to  claim 1 , in which a device is provided to guide the air and gas mixture towards the burner head ( 3 ), said device comprising a wall ( 12 ) positioned inside the dome, and spaced apart from the inner surface of said dome, the flow of said air and gas mixture being guided between said surface of the head ( 3 ) and said wall ( 12 ), towards the burner head, said wall being positioned coaxially with the head ( 3 ) and having a curved profile with its convexity facing the burner head ( 3 ). 
     
     
         13 . A burner according to  claim 12 , in which said wall ( 12 ) is formed by a shaped sheet of metal. 
     
     
         14 . A burner according to  claim 12 , in which a deflector element ( 14 ) is provided between said wall ( 12 ) and the head ( 3 ) to divert the flow of the combustible mixture. 
     
     
         15 . A burner according to  claim 14 , in which said deflector element ( 14 ) extends coaxially with the head, ( 3 ) and is spaced apart from said wall ( 12 ). 
     
     
         16 . A burner according to  claim 14 , in which said deflector element ( 14 ) extends radially from said flange ( 8 ) and runs circumferentially inside the dome of the burner head ( 3 ). 
     
     
         17 . A burner according to  claim 12 , in which a distributor element ( 11 ) is provided between said wall ( 12 ) and the head ( 3 ), for supplying the flow of the combustible mixture towards the head ( 3 ). 
     
     
         18 . A burner according to  claim 17 , in which said distributor element ( 11 ) extends coaxially with the head ( 3 ), and is spaced apart from it. 
     
     
         19 . A burner according to  claim 17 , in which said distributor element ( 11 ) has a plate-like shape with a curved profile, having its convexity facing the burner head ( 3 ). 
     
     
         20 . A burner according to  claim 19 , in which said distributor element ( 11 ) comprises a plurality of through holes for distributing the mixture over the surface of the burner head ( 3 ). 
     
     
         21 . A burner according to  claim 20 , in which said distributor element ( 11 ) and said guide wall ( 12 ) form a guide passage whose annular section, in the direction of the flow, decreases towards the principal axis of the dome.