Method and apparatus for optimizing fuel-to-air ratio in the combustible gas supply of a radiant burner

In a heating appliance employing a radiant burner that burns a combustible gas comprised of a mixture of gaseous fuel and combustion air and that emits radiation while burning said combustible gas, having means for supplying said gaseous fuel to said radiant burner at at least flow rate and having means for supplying said combustion air at a variable flow rate, an apparatus for setting the proportion of said gaseous fuel to said combustion air in said combustible gas to a desired proportion comprising:

• means for setting said gaseous fuel supply means at a given flow rate;
• means for measuring the unmodulated intensity of said radiation while varying the rate of supply of combustion air;
• means for deriving control parameters from measurements of the intensity of radiation from said burner;
• and
• means for applying said control parameters to control said combustion air supply means so as to reach and maintain a combustion air flow rate that results in said desired proportion.

In a heating appliance employing a radiant burner that burns a combustible gas comprised of a mixture of gaseous fuel and combustion air and that emits radiation while burning said combustible gas, having means for supplying said gaseous fuel to said radiant burner at at least one flow rate and having means for supplying said combustion air at a variable flow rate comprising an induction fan unity having a variable speed motor and controller, an apparatus for setting the proportion of said gaseous fuel to said combustion air in said combustible gas to a desired proportion comprising:

• means for setting said gaseous fuel supply means at a given flow rate;
• means for measuring the intensity of said radiation while varying the rate of supply of combustion air comprising a sensor that responds to said radiation with an output that varies with the intensity of said radiation;
• means for deriving control parameters from measurements of the intensity of radiation from said burner comprising a control device having microprocessor means;
• and
• means for applying said control parameters to control said combustion air supply means so as to reach and maintain a combustion air flow rate that results in said desired proportion.