# US 4,397,293 A · Heating apparatus comprising a heat recovery apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,397,293 A - Document ID: US4397293A - Status: Granted - Kind: A - Application number: 06/266,079 - Filed: 1981-05-21 - Granted: 1983-08-09 - Earliest claimed: 1980-05-21 - Inventors: Thierry Pibernat - Web page: https://patentgrep.com/patent/US4397293A ## CPC - F24B 5/04: the air or gas passing downwards through the bottom of the stove of fire grate - F24B 1/1886: {the heat exchanger comprising only tubular air ducts within the fire} - F24B 7/04: with internal air ducts - Y10S 165/901: Heat savers - F24B: DOMESTIC STOVES OR RANGES FOR SOLID FUELS (for solid fuels in combination with gaseous fuels, liquid fuels or other kinds of energy supply F24C1/02); IMPLEMENTS FOR USE IN CONNECTION WITH STOVES OR RANGES - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A heating apparatus includes at least one combustion air inlet, a reverse-draft hearth having a grill positioned within a hearth plate, an ash receptacle for recovering combustion wastes, a fume outlet, a combustion chamber positioned under the reverse-draft hearth, and a heat recovery device. A heat transport and exchange fluid is adapted to be fed through the heat recovery device, and it circulates through the device in order to recover heat generated in the hearth. The heat recovery device also includes at least one casing positioned beneath the hearth, over the ash receptacle, and which is spaced from the walls of the heating apparatus. The rear portion of the casing is connected to the hearth plate so as to block combustion gases so that the combustion gases will pass over and thereafter under the casing prior to leaving the apparatus via the fume outlet. ## Claims ### Claim 1 A heating apparatus comprising: (a) a plurality of walls; (b) at least one combustion air inlet; (c) a reverse-draft hearth having a grill located within a hearth plate; (d) an ash receptacle for recovering combustion wastes; (e) a fume evacuation outlet; (f) a combustion chamber positioned under said hearth; and (g) a heat recovery device adapted to retain a heat-exchange fluid, said heat recovery device being positioned at least partially under said hearth, and comprising at least one casing positioned between said hearth and said ash receptacle and spaced from said apparatus walls, said casing including a rear portion which is connected to said hearth plate by means for blocking combustion gases, said apparatus including means for conducting combustion gas first above said casing, then under said casing, and means for combining said gas with smoke being evacuated through said outlet. ### Claim 2 (depends on 1) Heating apparatus in accordance with claim 1 wherein a conduit combines said combustion gas and said evacuated smoke at the rear of said hearth. ### Claim 3 (depends on 1) Heating apparatus in accordance with claim 1 further comprising a second, vertical casing connected to said at least one casing, both of said casings positioned within an enclosure which is in fluidic communication with said combustion chamber, said second, vertical casing being spaced from the walls of said heating apparatus so that hot gases within said enclosure will surround said vertical casing. ### Claim 4 (depends on 3) Heating apparatus in accordance with claim 3 wherein said heat recovery device includes a heat-exchange surface which decreases in a direction extending upwardly from said at least one casing, where heat exchange is greatest, towards said second, vertical casing, where heat exchange is lowest. ### Claim 5 (depends on 4) Heating apparatus in accordance with claim 4, wherein said second casing generally is in the shape of an isosceles trapezoid and has a heat-exchange surface which decreases from a lower portion of the second casing, which lower portion is connected to the first casing, towards an upper portion of said second casing. ### Claim 6 (depends on 1) Heating apparatus in accordance with claim 1 wherein said at least one casing is inclined, with respect to said hearth plate, towards the front of said apparatus in order to direct ashes into a removable ash receptacle. ### Claim 7 (depends on 1) Heating apparatus in accordance with claim 1 wherein said at least one casing is positioned within said combustion chamber. ### Claim 8 (depends on 1) Heating apparatus in accordance with claim 1 further comprising an enclosure between said at least one casing and said apparatus walls, and wherein a channel is provided between said combustion chamber, said enclosure, and said casing, said channel adapted to conduct heat flow, under reverse-draft action, towards the front of said apparatus. ### Claim 9 (depends on 1) Heating apparatus in accordance with claim 1 further comprising a removable ash receptacle positioned within said combustion chamber. ### Claim 10 (depends on 1) Heating apparatus in accordance with claim 1 wherein said at least one casing is positioned within said combustion chamber and adapted to be placed into contact with combustion. ### Claim 11 (depends on 1) Heating apparatus in accordance with claim 1 wherein said at least one casing includes a plurality of baffles. ### Claim 12 (depends on 1) Heating apparatus in accordance with claim 1 wherein said heat recovery device is spaced from the walls of an ash recovery receptacle and from said combustion chamber, most of said combustion gas adapted to pass about a front end of said casing. ### Claim 13 (depends on 1) Heating apparatus in accordance with claim 1 wherein a grill bounds an upper portion of the combustion chamber. ### Claim 14 (depends on 2) Heating apparatus in accordance with claim 2 wherein said enclosure includes at least one selectively operable damper for controlling gas and smoke flow through said evacuation outlet. ### Claim 15 (depends on 1) Heating apparatus in accordance with claim 1 further comprising a plate valve positioned within said air inlet for controlling the introduction of air into the apparatus.