Gas water heater/boiler

A burner assembly for a gas-fired water heater/boiler apparatus comprising:

• a burner tube including a venturi portion, a mixing portion, and a burner portion, said burner portion having an inner perforated tube and an outer perforated tube superimposed on said inner perforated tube, said inner perforated tube comprising a plurality of first perforations of uniform size and distribution thereby giving said inner perforated tube an open area of approximately 45, said outer perforated tube comprising a plurality of second perforations of uniform size and distribution that are substantially larger than said first perforations thereby giving said outer perforated tube an open area of approximately 65, whereby when said outer perforated tube is superimposed over said inner perforated tube a portion of said first perforations are covered and said burner portion has a net open area of approximately 29%,
• a gas supply line,
• an orifice connected to said supply line, said orifice having a cylindrical body closed at one end and a circumferential row of orifice apertures in said body near said supply line whereby gas entering said body from said supply line will cause turbulence when exiting said orifice through said orifice apertures, said orifice being supported in the open end of said venturi portion, and
• a plurality of venturi openings in the wall of said venturi portion of said burner tube between said orifice and said perforated tubes, whereby when combustion air enters said venturi portion through said open top or said venturi openings, said turbulence caused by said orifice creates a gas/air mixture that is sufficient to support combustion when said gas/air mixture passes through said perforations of said burner portion and is ignited.

A gas-fired water heater/boiler apparatus comprising:

• an inner sealed casing having a top,
• a heat exchanger unit disposed within said casing, said heat exchanger unit comprising a vertically standing circular array of finned heat exchanger tubes connected to upper and lower headers,
• a gas burner assembly disposed vertically through said top and through said upper header with a burner portion of said burner assembly extending downwardly into the space defined by said heat exchanger tubes, said burner assembly having a venturi portion retained above said top of said inner casing by a support collar attached to said burner assembly, said venturi portion comprising a tubular body open at its top, said burner portion including a pair of superimposed perforated tubes that are closed at their lower end, each of said tubes having a plurality of evenly distributed perforations therein of a different uniform size, wherein the perforations of the inner superimposed tube are smaller than the perforations of the outer superimposed tube, said burner portion and said perforations therein extending substantially the entire length of said finned heat exchanger tubes,
• an outer sealed casing surrounding said inner casing and said venturi portion of said burner assembly, said outer casing forming a sealed forehearth comprising a space between said inner casing and the interior of said outer casing,
• a gas supply means which passes through said outer casing and is connected to an orifice situated in the top of said venturi portion, and
• a combustion air intake means located within said sealed forehearth, whereby said air intake means draws combustion air through an inlet located on said exterior casing and pressurizes said forehearth with combustion air thereby preventing leakage of flue products and thereby insulating said apparatus.