Method and apparatus for fuel/air control of surface combustion burners
AssigneeGas Research Institute
InventorMartin F. Zabielski, Sr.
Life of this patent
Estimating the term…
Abstract
A fuel/air control system for use in controlling the operation of a surface combustion burner includes a photodetector that provides electrical signal equivalents of burner flame emission to a controller. The controller simultaneously receives signals indicative of the fuel/air mixture. The controller fits the emission and fuel air mixture data to a fourth order polynomial. Thereafter, the mathematical inflection point is computed and the corresponding fuel/air mixture is determined. The controller then generates command signals to adjust and maintain the burner at the inflection point fuel/air mixture. Multiple burner control can also be achieved with the present fuel/air control system without the need to sample exhaust gas.
Claims19
A system for use in controlling the operation of a surface burner generating a flame producing emissions having a carbon monoxide concentration, said system comprising:
- a detector means for generating electrical signal equivalents corresponding to the intensity of electromagnetic radiation from said flame;
- an air valve for providing a controlled flow of air to said surface burner in accordance with received air valve command signals;
- a fuel valve for providing a controlled flow of fuel to said surface burner in accordance with received fuel valve command signals;
- a controller for generating said fuel valve and air valve signals such that fuel/air ratio is established, said controller including
- a means for generating said fuel valve and air valve signals over a selected range of fuel/air ratios;
- a means for sampling said detector means signals for each of said fuel/air ratios in said selected range;
- a means for determining a mathematical relationship between said sampled detector means signals and said selected fuel/air ratios;
- a means for computing a first differential relationship from said mathematical relationship;
- a means for computing a second differential relationship from said first differential relationship;
- a means for computing roots of a quadratic relationship wherein said second differential relationship is set equal to zero;
- a means for identifying the one of said roots that corresponds to a solution to said quadratic relationship within said fuel/air ratio selected range, said identified root corresponding to a fuel/air ratio at which carbon monoxide onset occurs wherein the carbon monoxide concentration begins to increase in magnitude;
- and
- a means for generating said air valve and fuel valve command signals to operate the surface burner at the fuel/air ratio corresponding to the acceptable root.
A method for controlling the operation of a surface burner generating a flame producing emissions having a carbon monoxide concentration, said method comprising the steps of:
- generating electrical signal equivalents corresponding to the intensity of electromagnetic radiation from said flame;
- generating command signals for an air valve to provide a controlled flow of air to said surface burner;
- generating command signals for a fuel valve to provide a controlled flow of fuel to said surface burner;
- a controlling said fuel valve and air valve signals such that a fuel/air ratio is established including the steps of
- generating said fuel valve and air valve signals over a selected range of fuel/air ratios;
- sampling said detector means signals for each of said fuel/air ratios in said selected range;
- determining a mathematical relationship between said sampled detector means signals and said selected fuel/air ratios;
- computing a first differential relationship from said mathematical relationship;
- computing a second differential relationship from said first differential relationship;
- computing roots of a quadratic relationship wherein said second differential relationship is set equal to zero;
- identifying the one of said roots that corresponds to a solution to said quadratic relationship within said fuel/air ratio selected range, said identified root corresponding to a fuel/air ratio at which carbon monoxide onset occurs wherein the carbon monoxide concentration begins to increase in magnitude;
- and
- generating said air valve and fuel valve command signals in accordance with said acceptable root to operate said surface burner at said identified root.
In a system for use in controlling the operation of a surface burner having a detector means for generating electrical signal equivalents corresponding to the intensity of electromagnetic radiation from a surface burner flame producing emissions having a carbon monoxide concentration, an air valve for providing a controlled flow of air to said surface burner in accordance with received air valve command signals, a fuel valve for providing a controlled flow a fuel to said surface burner in accordance with received fuel valve command signals, a controller for generating said fuel valve and air valve signals such that a fuel/air ratio is established, said controller comprising:
- a means for generating said fuel valve and air valve signals over a selected range of fuel/air ratios;
- a means for sampling said detector means signals for each of said fuel/air ratios in said selected range;
- a means for determining a mathematical relationship between said sampled detector means signals and said selected fuel/air ratios;
- a means for computing a first differential relationship from said mathematical relationship;
- a means for computing a second differential relationship from said first differential relationship;
- a means for computing roots of a quadratic relationship wherein said second differential relationship is set equal to zero;
- a means for identifying the one of said roots that corresponds to a solution to said quadratic relationship within said fuel/air ratio selected range, said identified root corresponding to a fuel/air ratio at which carbon monoxide onset occurs wherein the carbon monoxide concentration begins to increase in magnitude;
- and
- a means for generating said air valve and fuel valve command signals to operate the surface burner at the fuel/air ratio corresponding to the identified root.
Dependencies are inferred from the claim text.