Gas-liquid heat exchanger,and water heater having such a heat exchanger

摘要

The gas-liquid heat exchanger (8) comprises a gas conduit extending in a longitudinal direction and a liquid circuit. The liquid circuit comprises first and second metal manifolds (13,14), several metal tubes (15) connecting the manifolds which extend into the gas conduit. Liquid inlet (16) and outlets (17) are connected so that the manifolds and tubes are passed through by a liquid flow. Each tube in the liquid circuit is coiled in a plane parallel to the longitudinal direction of the gas conduit. This coil has a three rectilinear sections (18,20,22) connected by 2 pairs of elbows. Each tube has an end rectilinear section which is welded to the first manifold by a welding bead (26). It has a second end rectilinear section which is welded to the second manifold. The different coil planes are parallel to one another and the two manifolds are in two planes parallel to the longitudinal direction of the gas conduit but perpendicular to the different planes of the tubes.