Abstract: The heat recovery device includes a section of standard flue pipe carrying a single row of a plurality of hollow, cylindrical heating tubes extending diametrically through the flue pipe section and a separate housing defining an air flow chamber surrounding the portion of the flue pipe section containing the heating tubes. A fan inside the housing draws ambient air into the housing and propels a flow of air toward a heated air outlet, both through the heating tubes and over the outer surface of the flue pipe section. A catalytic combustor for reducing air pollutants and potential creosote deposits is mounted in the flue pipe section upstream of the heating tubes. The flue pipe assembly is removably mounted on the housing so it can be removed in the event it fatigues and/or becomes plugged with carbon or creosote deposits during use. A thermostat on the flue pipe section turns the fan on and off when the temperature in the flue pipe section is respectively above and below a predetermined temperature.

Abstract: The heat recovery device has a flue pipe assembly including a section of standard flue pipe carrying a plurality of hollow, cylindrical heating tubes extending diametrically through the flue pipe section in axially spaced, parallel relationship and a separate housing defining an air flow chamber surrounding a portion of the flue pipe section. A fan inside the housing draws ambient air into the housing through an ambient air inlet located on the same side of the flue pipe assembly as the inlet of the heating tubes and propels a flow of air both through the heating tubes and over the outer surface of the flue pipe section towards a heated air outlet located on the same side of the flue pipe section as the discharge ends of the heating tubes. The flue pipe assembly is removably mounted on the housing so it can be removed in the event it fatigues and/or becomes plugged with carbon or creosote deposits during use.