Household heating furnace with combustion products recirculation

Claim 1

A FURNACE COMPRISING AN UPRIGHT HOLLOW HEAT EXCHANGER HAVING AN OUTLET AT ITS LOWER END AND HAVING A FRONT WALL AND A REAR WALL, SAID REAR WALL HAVING NEAR THE TOP OF THE EXCHANGER AN INLET FOR PRODUCTS OF COMBUSTION, A RECIRCULATING DUCT HAVING A GENERALLY UPRIGHT PORTION FOR THE PRODUCTS OF COMBUSTION AT THE REAR OF THE EXCHANGER AND HAVING A FORWARDLY EXTENDING DUCT INLET PORTION CONNECTED TO SAID OUTLET OF THE EXCHANGER AND A FORWARDLY EXTENDING DUCT OUTLET PORTION DIRECTED INTO THE INLET OF THE EXCHANGER, AND SUBSTANTIALLY COEXTENSIVE AND COAXIAL THEREWITH, A COMBUSTION CHAMBER IN THE OUTLET PORTION OF SAID DUCT AND EXTENDING ENDWISE FORWARDLY THEREOF FROM THE REAR THEREOF TOWARD THE EXCHANGER AND HAVING A DISCHARGE OPENING AT ITS FORWARD END ALIGNED WITH, DIRECTED INTO, AND OF SMALLER CROSS SECTION THAN, THE HEAT EXCHANGER INLET, SAID COMBUSTION CHAMBER HAVING A PERIPHERAL OUTER SIDE WALL IN RADIALLY INWARDLY SPACED RELATION TO THE SIDE WALL OF THE DUCT OUTLET PORTION AND DEFINING THEREWITH AN ANNULAR PASSAGE FOR THE PRODUCTS OF COMBUSTION BETWEEN THE EXTERIOR OF THE PERIPHERAL WALL OF THE COMBUSTION CHAMBER AND THE SIDE WALL OF THE DUCT OUTLET PORTION, AND DIRECTED INTO THE EXCHANGER INLET SO THAT THE PRODUCTS OF COMBUSTION BEING RECIRCULATED PASS AS AN ANNULAR STREAM INTO THE EXCHANGER INLET AND CREATE A LOW PRESSURE AREA SURROUNDING THE DISCHARGE OPENING OF THE COMBUSTION CHAMBER, BURNER MEANS FOR SUPPLYING COMBUSTIBLE HYDROCARBON FUEL INTO SAID COMBUSTION CHAMBER, A POER DRIVEN RECIRCULATING BLOWER IN THE RECIRCULATING DUCT, SAID BLOWER HAVING ITS INLET CONNECTED WITH THE DUCT INLET AND ITS OUTLET DISCHARGING UPWARDLY IN THE UPRIGHT PORTION OF THE DUCT FOR RECIRCULATING PRODUCTS OF COMBUSTION FROM THE EXCHANGER BY DRAWING THE PRODUCTS FROM THE OUTLET OF THE HEAT EXCHANGER AND BLOWING THEM THROUGH THE DUCT AND OUT THROUGH THE DUCT OUTLET PORTION SO THAT THEY PASS THROUGH THE SPACE BETWEEN THE PERIPHERAL WALL OF THE COMBUSTION CHAMBER AND THE SIDE WALL OF THE OUTLET PORTION OF THE DUCT AND INTO THE EXCHANGER INLET AS AN ANNULAR STREAM, MEAND FOR SUPPLYING OUTSIDE AIR TO THE BURNER MEANS, BLEEDER DUCT MEANS FOR CONTINUALLY BLEEDING INTO THE ATMOSPHERE A FRACTION OF THE PRODUCTS OF COMBUSTION BEING RECIRCULATED, AND SAID BLEEDER DUCT MEANS HAVING ITS INLET CONNECTED TO THE RECIRCULATION DUCT AT A LEVEL BELOW THE RECIRCULATION DUCT OUTLET PORTION SO AS TO AIR LOCK A SUBSTANTIAL PORTION OF THE HEAT EXCHANGER AGAINST BLEEDING OFF A HEATED PRODUCTS WHEN THE FURNACE IS NOT OPERATING.