Heat exchange cell for a heating boiler

Abstract

A heat exchange cell for a heating boiler includes a casing with a sidewall enclosing an internal space, the sidewall having an open front end surrounded by an annular edge of the casing front end. A sheet metal annular closing flange has an opening and radially internal, intermediate and external flange edges. The radially external flange edge connects to the casing sidewall along the annular edge. The radially internal edge defines radially internal and external surfaces. A front edge surface connects the radially internal surface and radially external surface. The front edge surface defines a lying plane on which the front edge surface lies, the lying plane defining an axial direction orthogonal to the lying plane and passing through the opening, and a radial direction orthogonal to the axial direction. The radially internal surface extends parallel to the axial direction protruding towards an outside of the cell.

1 . A heat exchange cell for a heating boiler, comprising:
 a casing comprising a side wall enclosing an internal space, said side wall having an open front end surrounded by an annular edge of the front end of the casing,   an annular closing flange made from a sheet metal having a flange through opening to allow the access to the inside of the casing, said closing flange defining a radially internal flange edge surrounding said through opening, a radially external flange edge arranged around said radially internal edge, an intermediate flange portion connecting the radially external flange edge and the radially internal flange edge to one another, said radially external flange edge being connected to said side wall of the casing along said annular edge of the front end of the casing,   wherein said radially internal edge defines a radially internal surface, a radially external surface arranged around said radially internal surface, a front edge surface connecting said radially internal surface and said radially external surface to one another, said front edge surface defining a lying plane on which said front edge surface lies, said lying plane defining an axial direction orthogonal to the lying plane and passing through the through opening, and a radial direction orthogonal to the axial direction,   wherein said radially internal surface extends parallel to the axial direction in a manner protruding towards the outside of the cell with respect to said intermediate flange portion.   
     
     
         2 . A cell according to  claim 1 , wherein a cross-section orthogonal with respect to the axial direction of the radially internal surface is constant along the axial direction. 
     
     
         3 . A cell ( 1 ) according to  claim 1 , wherein the radially internal surface and the radially external surface are defined by two respective sheet metal portions, folded with one another in a superimposed double layer. 
     
     
         4 . A cell according to  claim 1 , wherein said flange is entirely formed in one piece from a single piece of sheet metal by plastic deformation. 
     
     
         5 . A cell according to  claim 1 , comprising:
 a heat exchanger mounted inside the casing, said exchanger comprising at least one tubular duct helically wound about a helix axis arranged along the axial direction, forming a plurality of coils, said plurality of coils ending with an end helical coil facing towards said closing flange;   wherein said intermediate annular flange portion is shaped to adhere with continuity to said end helical coil.   
     
     
         6 . A cell according to  claim 5 , wherein said intermediate annular flange portion is shaped according to a single helicoid ring joined at ends of the ring by a step portion. 
     
     
         7 . A cell according to  claim 6 , wherein the closing flange comprises axial protrusions extending from the radially internal edge towards inside of the cell, wherein the axial protrusions form a centering of the exchanger with respect to said closing flange. 
     
     
         8 . A cell according to  claim 1 , wherein the closing flange comprises at least one flat portion extending from the radially external edge towards the radially internal edge, said flat portion lying on a plane orthogonal to the axial direction, wherein each of said at least one flat portions is adapted to support a respective fastening pin to fasten the door to the closing flange, arranged according to the axial direction. 
     
     
         9 . A cell according to  claim 5 , wherein the intermediate flange portion comprises at least one annular channel internally facing the cell, adapted to receive a sealing material interposed between the intermediate flange portion and the end helical coil of the exchanger. 
     
     
         10 . A cell according to  claim 1 , comprising a door configured to be removably fastened to said closing flange to close said through opening, said door comprising a disc comprising a refractory insulating material, said disc being delimited by a side disc surface; wherein the radially internal surface is configured to surround and externally embrace the side disc surface and to allow axial sliding thereof. 
     
     
         11 . A cell according to  claim 10 , comprising a thermal barrier device and a fume seal device, separate from one another and interposed between said closing flange and said door along said radially internal edge. 
     
     
         12 . A cell according to  claim 11 , wherein the thermal barrier device is interposed, in the axial direction, between said front edge surface and said door. 
     
     
         13 . A cell according to  claim 12 , wherein the fume seal device is interposed, in the radial direction, between the radially external surface of the closing flange and a peripheral radial seal edge of said door. 
     
     
         14 . A cell according to  claim 12  or  13 , wherein the thermal barrier device comprises, an annular peripheral protrusion of said disc, protruding, in the radial direction, from the side surface of said disc, said annular peripheral protrusion forming an abutment surface lying on a plane orthogonal to the axial direction and configured to axially adhere to said front edge surface of the closing flange. 
     
     
         15 . A cell according to  claim 11 , wherein the thermal barrier device is interposed, in the radial direction, between the radially internal surface of the closing flange and said door. 
     
     
         16 . A cell according to  claim 15 , wherein the fume seal device is interposed, in the axial direction, between the front edge surface and the door. 
     
     
         17 . A cell according to  claim 11 , wherein the thermal barrier device comprises a gasket, selected among a ceramic fiber cord gasket, or a glass fiber cord gasket, or a graphite gasket. 
     
     
         18 . A cell according to  claim 11 , wherein the fume seal device comprises a gasket selected between a rubber gasket or a silicone gasket.