Combustion control method

A method for controlling combustion condition in a combustion facility, the combustion facility including a combustion apparatus having a burner, a fuel feeding pipe connected to the burner and having a fuel control valve for controlling the feed of fuel, an air feeding pipe connected to the burner and having an air control valve for controlling the feeding of air;

• a detection device for detecting radiated light originating in a combustion flame of the burner, and a combustion controller for controlling an open position of the air control valve based on detection data from the detection device, the method comprising the steps of:
• A) converting the radiated light detected by the detection device into a first electric signal, wherein said first electric signal includes an intensity signal element corresponding to the intensity of the detection light and an oscillation signal element corresponding to fluctuations of the combustion flame caused by the feeding of air to the burner;
• B) extracting said oscillation signal element from said first electric signal;
• C) extracting from said first electric signal an intensity factor signal element on the basis of the oscillating signal element, the intensity factor signal element being representative of a real intensity of the radiated light originating in only the combustion flame, the step of extracting the intensity factor signal includes the substeps of rectifying the oscillation signal element, and integrating the rectified signal;
• D) generating a second electric signal by dividing said oscillation signal element by said intensity factor, so as to compensate said oscillation signal element which is influenced by the intensity of radiated light;
• E) applying frequency analysis to said second electric signal;
• F) calculating an oscillation power based on the result of the frequency analysis, wherein said oscillation power is related to the state of the combustion flame;
• and
• G) performing feedback-control of the open position of the air control valve, in such a manner that said calculated oscillation power approaches a predetermined optimum oscillation power.

A method for controlling combustion condition in a combustion facility, the combustion facility including a combustion apparatus having a burner, a fuel feeding pipe connected to the burner and having a fuel control valve for controlling the feeding of fuel, an air feeding pipe connected to the burner and having an air control valve for controlling the feeding of air;

• a detection device for detecting radiated light originating in a combustion flame of the burner;
• and a combustion controller for controlling an open position of the air control valve based on the detection data from the detection device, the method comprising the steps of:
• A) converting the radiated light detected by the detection device into a first electric signal, wherein said first electric signal includes an intensity signal element corresponding to the intensity of the detected light and an oscillation signal element corresponding to fluctuations of the combustion flame caused by the feeding of air to the burner;
• B) extracting said oscillation signal element from said first electric signal;
• C) extracting an intensity factor, representative of a real intensity of the radiated light originating in only the combustion flame, from said first electric signal;
• D) applying frequency analysis to said extracted oscillation signal element, thereby obtaining power spectrum values of the individual signals corresponding to respective frequencies in said frequency analysis;
• E) dividing each of said power spectrum values by said intensity factor;
• F) summing up all of said divided power spectrum values to calculate an oscillation power, wherein said oscillation power is related to the state of the combustion flame;
• and
• G) performing feedback-control of the open position of the air control valve, in such a manner that said calculated oscillation power approaches a predetermined optimum oscillation power.