Heat exchanger furnace

A heat exchanger furnace, comprising,

• a firebox,
• a heat exchanger housing in communication with said firebox for receiving combustion gases therefrom, said housing being at least partially defined by at least one upright sidewall,
• a plenum housing surrounding said heat exchanger housing and spaced therefrom to define a plenum chamber therebetween,
• a plurality of baffles having outer peripheral edges,
• means for supporting said baffles generally centrally of said heat exchanger housing in vertically spaced apart and generally horiztonally extended relation therein,
• said baffles being of a size and shape to substantially fill the horizontal cross section of said heat exchanger housing and to define openings between said peripheral edges of said baffles and the heat exchanger housing whereby hot combustion gases rising within said heat exchanger housing are directed outwardly adjacent said sidewall,
• said plenum chamber including air inlet and outlet openings arranged in vertically spaced apart relation and further comprising forced air circulation means associated with said plenum chamber for forced air flow into said inlet opening, through said plenum chamber and out said outlet opening,
• said forced air circulation means including a fan, and further comprising means for supporting said fan adjacent said inlet opening and a baffle means in said plenum chamber between said inlet and outlet openings for distributing airflow throughout said plenum chamber,
• said baffle means comprising a member which substantially blocks the horizontal cross-section of said plenum chamber, said member including a plurality of openings generally uniformly spaced apart about said member,
• at least one exhaust pipe in communication with an upper portion of said heat exchanger housing, said exhaust pipe extending outwardly of said plenum housing for exhausting combustion gases, and said exhaust pipe including a generally U-shaped portion having a first leg extended downwardly into said plenum chamber and a second leg extended upwardly and outwardly of said plenum chamber for persenting additional heat exchange surfaces within said plenum chamber, and
• an air inlet passage in communication at one end with said firebox, means for supplying air under pressure to said firebox through said air inlet passage, a fuel inlet passage in communication at one end with said firebox, means for supplying fuel to said firebox through said fuel inlet passage, and means establishing communication between said air inlet passage and fuel inlet passage whereby air introduced into said fuel inlet passage under pressure is operative to prevent the escape of combustion gases from said firebox through said fuel inlet passage.