Downdraft gas range with dual mode burner system

A method of dual mode cooking with a gas burner and a downdraft exhaust, comprising:

• providing an atmospheric and a powered mode of gas burner operation;
• and
• further comprising in the powered mode of gas burner operation;
• creating a forced flow of a combustion air at a pressure above atmospheric pressure;
• mixing the forced flow of combustion air with a flow of gas;
• directing the mixture of the forced flow of combustion air and gas to the gas burner through a sealed conduit;
• controlling the flows of combustion air and gas to provide a controlled variable combustion of gas at the gas burner;
• combusting the directed flow of gas with the combustion air at the gas burner for cooking;
• and
• exhausting gaseous combustion and cooking by-products by providing a downdraft adjacent the gas burner, and
• further comprising in the atmospheric mode of gas burner operation;
• directing a flow of gas and an induced flow of air from atmosphere to the gas burner through said sealed conduit;
• controlling the flow of gas to the gas burner;
• and
• combusting the gas at the gas burner while precluding operation of the downdraft exhaust.

A dual mode downdraft gas range, comprising:

• a cooktop comprising a top surface adapted to be sealed to a plurality of gas burner assemblies;
• a downdraft plenum having an inlet adjacent the plurality of gas burner assemblies adapted to withdraw combustion byproducts and cooking vapors from adjacent the top surface and said plurality of burners,
• a downdraft exhaust blower having its inlet connected with said downdraft plenum;
• an air plenum adjacent the top surface of the cooktop;
• a combustion air blower with its outlet connected with the air plenum and its inlet open to atmosphere, said air blower being adapted to pressurize said air plenum above atmospheric pressure with a flow of air when operated and to permit a flow of air from atmosphere to said air plenum when not in operation;
• a plurality of combined air and gas flow supply means, one for each of said plurality of gas burner assemblies;
• each of said plurality of combined air and gas flow supply means comprising:
• means forming a separate gas/air mixing chamber having a common wall with said air plenum, and said common wall having an air flow opening communicating with each separate gas/air mixing chamber whereby air may flow from said air plenum into each said gas/air mixing chamber;
• means to control both the flow of gas and the flow of air into the gas/air mixing chamber;
• means within the gas/air mixing chamber for combining a flow of gas with a flow of air;
• and
• a plurality of sealed conduits, each sealed conduit leading from one of said gas/air mixing chambers to one of said plurality of gas burner assemblies.