Burner

Abstract

A gas burner for a heater comprises a planar metal frame portion with an elongated opening defined by two longitudinal edges and by two transversal end edges, as well as a combustion membrane in the form of a tridimensional shell, connected to the frame portion along the longitudinal and transversal edges, wherein the combustion membrane has a diffuser layer, which forms an outer combustion surface made of a perforated metal sheet, and which extends between the two longitudinal edges with a single curvature out of the plane of the frame portion, and two closure portions made of metal sheet extending from the transversal edges out of the plane of the frame portion and which close end areas between the diffuser layer and the transversal edges of the frame portion.

1 . A gas burner for a heater, comprising:
 a planar, metal frame portion with an elongated opening defined by two longitudinal edges extending in the direction of a longitudinal axis of the burner and mutually opposite and facing, and by two end edges transversal to the longitudinal axis,   a combustion membrane in the form of a tridimensional shell, connected to the frame portion along the longitudinal edges and transversal edges, said combustion membrane having:   a diffuser layer forming an outer combustion surface made of a perforated metal sheet, and extending between the two longitudinal edges with a single curvature out of the plane of the frame portion,   two closure portions in metal sheet extending from the transversal edges out of the plane of the frame portion and which close end areas between the diffuser layer and the transversal edges of the frame portion,   wherein both closure portions and the frame portion are formed in a single piece of metal sheet, by folding the closure portions along the transversal edges of the opening.   
     
     
         2 . The burner according to  claim 1 , wherein the diffuser layer with the combustion surface has a sectional shape transversal to the longitudinal axis selected from the group consisting in the shapes as follows:
 arch,   circular arch,   circular arch tapering in the direction of the frame,   arch composed of alternate curved and rectilinear lengths,   arch composed of a plurality of curved lengths with different curvature radiuses,   arch composed of multiple rectilinear lengths inclined to each other,   arch with a rectilinear apical length,   arch with two opposite rectilinear side lengths,   arch with two opposite rectilinear side lengths and a rectilinear apical length and two curved rounded lengths arranged between the side lengths and the apical length,   wavy.   
     
     
         3 . The burner according to  claim 1 , wherein the diffuser layer with the combustion surface has a uniform cross section along the longitudinal extension of the combustion surface. 
     
     
         4 . The burner according to  claim 1 , wherein the closure portions form:
 a wall substantially planar and transversal to the plane of the frame portion, and   a folded edge connecting the planar wall to the diffuser layer, said folded edge having an arched shape substantially compatible with the arched shape of the diffuser layer.   
     
     
         5 . The burner according to  claim 1 , wherein the closure portions each form a wall substantially planar and perpendicular to the plane of the frame portion. 
     
     
         6 . The burner according to  claim 1 , comprising one or more stiffening ribs extending from the frame through the transversal edge up into the closure portion. 
     
     
         7 . The burner according to  claim 1 , wherein at least a part of the combustion membrane is formed together with the frame portion in a single piece of metal sheet. 
     
     
         8 . The burner according to the  claim 4 , wherein cut-outs of the frame portion at the ends of the longitudinal edges in the corner areas with the transversal edges are sealed by local welds which create irreversible securing points between the diffuser layer and the frame. 
     
     
         9 . The burner according to  claim 1 , wherein at least one portion of the combustion membrane is connected to the frame portion by elastic fit, in particular by snap fit. 
     
     
         10 . The burner according to  claim 1 , comprising a distributor in metal sheet with a plurality of through openings arranged on a feeding side of the diffuser layer to distribute the fuel mix in a desired manner towards the diffuser layer. 
     
     
         11 . The burner according to  claim 10 , wherein said distributor is connected to the frame portion or the diffuser layer by elastic fit. 
     
     
         12 . The burner according to  claim 10 , wherein said distributor and said diffuser layer are formed together in a single piece of metal sheet.