Balanced draft space heater

Claim 1

IN A SPACE HEATER TO BE PLACED IN A ROOM, INNER AND OUTER UPRIGHT SHELLS ARRANGED ONE WITHIN THE OTHER AND HAVING VERTICAL SIDE WALLS AND TRANSVERSE TOP AND BOTTOM WALLS, EACH SIDE AND TRANSVERSE WALL OF ONE SHELL BEING OPPOSED TO AND SPACED FROM THE CORRESPONDING SIDE AND TRANSVERSE WALL OF THE OTHER SHELL, SAID INNER SHELL PROVIDING A COMBUSTION CHAMBER THEREIN, A FUEL BURNER IN THE LOWER PORTION OF SAID CHAMBER, SAID INNER SHELL HAVING A FRESH-AIR INTAKE THEREINTO BELOW SAID BURNER FOR LEADING FRESH AIR TO SAID BURNER, AN UPRIGHT SIDE WALL BETWEEN A PAIR OF SAID OPPOSED VERTICAL SIDE WALLS AND HAVING ITS UPPER END TERMINATING BETWEEN THE TOP WALLS OF SAID SHELLS AND ITS LOWER END TERMINATING BELOW SAID FRESH-AIR INTAKE AND ABOVE SAID BOTTOM WALLS, A THIRD TOP WALL EXTENDING TRANSVERSELY FROM THE TOP OF SAID UPRIGHT SIDE WALL TO AN OPPOSED VERTICAL SIDE WALL OF SAID OUTER SHELL AND TOGETHER WITH THE INNER AND OUTER SHELLS FORMING A PAIR OF SEALEDAPART PASSAGEWAYS ONE OF WHICH COMMUNICATES WITH SAID FRESH-AIR INTAKE, AN AIR CIRCULATOR IN THE LOWER PORTION OF SAID INNER SHELL AND SEALED FROM SAID FRESH-AIR INTAKE AND HAVING AN AIR INTAKE OPENING THROUGH THE INNER SHELL VERTICAL SIDE WALL THAT IS ADJACENT AND OPPOSED TO SAID UPRIGHT SIDE WALL AND IS IN COMMUNICATION WITH THE OTHER PASSAGEWAY AND HAVING A DISCHARGE PIPE LEADING FROM SAID CIRCULATOR THROUGH THE BOTTOMS OF SAID SHELLS, AN UPRIGHT INNER