| 摘要 |
PURPOSE:To prevent incomplete combustion and back fire from developing by a method wherein combustion conditions in a main burner or a full primary combustion burner are detected and controlled with a pilot burner to burn highly concentrated premixed gas and a flame rod. CONSTITUTION:Because combustion air is divided and fed by an air feed pipe 27 in an air chamber 26, the excess air ratio lambda of premixed gas formed in a vaporizing chamber 4 is set to be 1.0 or less. The premixed gas and a part of the combustion air from the air chamber 26 mix with each other in a mixing chamber 10 so as to turn to comparatively lean mixture having the excess air ratio lambda of 1.0 or more in order to jet in a full primary combustion burner head 8. On the other hand, a part of the mixture from the vaporizing chamber 4 is led through a premixed gas extracting port 31, which is protrusively open to a mixture passage 28, to a pilot burner 30. Because the pilot burner 30 burns under the condition of low excess air ratio, ion current, obtained by inserting a flame rod in the flame produced on the pilot burner and applying electric voltage across the flame and the rod, shows the maximum value when the excess air ratio lambda of the mixture of the pilot burner is about 0.8-0.9. |
