Patent ID: 7267083
Filing Date: 2007-09-11
Classification: F24H,F28D

Abstract:
1. Condensation heat exchanger, associated with a gas or fuel oil burner ( 40 ), which is composed of two parallel tube bundles, one ( 21 ) termed “primary” and the other ( 31 ) termed “secondary”, each of these two bundles consisting of a tube, or a group of tubes disposed end to end, forming a helical coil, in which the wall of the tube(s) being made of a good thermal conductor and having a flattened and oval cross section with the major axis perpendicular, or approximately perpendicular, to that of the helix, while the width of the interstice separating two adjacent turns of the helical coil is constant and markedly smaller than the thickness of the said cross section, these two bundles being disposed close together and fixedly mounted within an envelope ( 1 ) which is impermeable to the gases, and communicating one with another via a collector ( 11 ) termed “transfer”, means being provided to cause circulation of a fluid to be heated, in particular liquid water, firstly within tube(s) constituting the said secondary bundle ( 31 ), then—via the said transfer collector ( 11 )—to the interior of the tube(s) constituting the said primary bundle ( 21 ), the said envelope ( 1 ) surrounding the two tube bundles while being closely spaced from each of them, this envelope ( 1 ) having a discharge cuff ( 7 ) for burnt gases, positioned in the neighbourhood of the said secondary bundle ( 31 ), this exchanger being formed so that the hot gases generated by the burner ( 40 ) pass radially, or approximately radially, passing through the interstices separating their turns, firstly through the primary bundle ( 21 ) and then the said secondary bundle ( 31 ), and are then discharged from the exchanger through the said cuff ( 7 ), characterised in that: the said burner ( 40 ) is a cylindrical burner whose diameter is substantially less than that of the primary bundle ( 21 ), and which is mounted coaxially within the latter, extending axially over all, or practically all, of its length; the axial dimension (l 2 ) of the said secondary bundle ( 31 ) is substantially smaller than that (l 1 ) of the said primary bundle ( 21 ), so that an available space is formed facing an end portion of the primary bundle, in the prolongation of the shorter secondary bundle; this available space is occupied by an enclosure ( 9 ) which communicates with the internal space ( 3 ) of the secondary bundle; the said cuff ( 7 ) is connected to the wall of the said enclosure ( 9 ) so as to communicate with it, and is oriented transversely with respect to the axis (X 2 X′ 2 ) of the secondary bundle ( 31 ), so that its bulk in the axial direction fits into that of the enclosure ( 9 ).