Patent ID: 7281497
Filing Date: 2007-10-16
Classification: F24H

Abstract:
1. A condensation heat exchanger associated with a gas or fuel burner, which comprises: at least one bundle of tubes, wherein the bundle includes one tube, or a group of tubes arranged end to end, forming a helical winding, in which the wall of the tube or tubes is made of a highly thermally conductive material and has a flattened oval cross section, wherein the major axis of the cross section is perpendicular, or approximately perpendicular, to that of the helix, while the width of a gap separating two adjacent turns is constant and appreciably smaller than the thickness of said cross section, a fluid heated up, in particular cold water, for circulating inside the tube or tubes constituting said bundle; and a gas-impermeable casing, wherein the bundle is fixedly mounted inside the gas-impermeable casing, the casing having a sleeve for the discharge of the burnt gases, wherein the exchanger is arranged such that the hot gases generated by the burner pass radially, or approximately radially, through said bundle via the gaps separating turns of the bundle, wherein said casing is made of heat-resistant plastic, wherein the casing contains retaining devices for mechanically retaining said bundle in an axial direction of the bundle, these retaining devices being able to absorb thrust loads resulting from the internal pressure of the fluid which circulates therein and which tends to deform the walls thereof, while preventing these loads from being transmitted to the casing, and wherein said retaining devices comprise a set of ties which extend outside the bundle, parallel to the axis of the helix, and whose ends are fixed to bearing elements pressing against the two opposed faces of the bundle.