Abstract: A heat recovery device such as an EGHR device includes a bypass valve, a gas/liquid heat exchanger and a flow duct. The flow duct has an open top and an open bottom. A top surface of the duct seals to a surface surrounding an opening of a gas flow conduit, such as an exhaust pipe. A duct wall extends from the top surface to the bottom surface, to which the heat exchanger is secured. The flow duct provides a passage through gas flows between the gas flow conduit and the heat exchanger. The bypass valve is mounted in the flow duct and is movable between a bypass position and a heat exchange position. The bypass valve may be mounted adjacent to the top or bottom of the duct, and may be a butterfly-type valve, a one-sided flap valve, or a pair of one-sided flap valves.

Abstract: A corrugated fin or turbulizer for a heat exchanger comprises a series of corrugations with parallel side walls. The side walls are provided with a series of parallel slits between which one-sided or two-sided louvers are defined. Each of the louvers has first and second edges extending along an adjacent pair of slits, and at least one bend located between the edges, thereby causing at least one of the edges of the louver to project outwardly of the plane of the side wall, and providing the side wall with improved crush resistance. The corrugations may preferably be rectangular or trapezoidal in form, having generally flat top and bottom surfaces defined by two closely-spaced bends. The top and bottom surfaces may preferably be provided with protrusions, at least some of which extend close to the bends. This assists in creating localized areas of weakness along which the bends can be formed cleanly.