| 摘要 |
PURPOSE:To shut off the feed of gas to a burner at the time of incomplete combustion, by a method wherein air holes are bored in front and in the rear of a combustion sensor tube, in a combustor, to which duct to introduce flame to a burner, a hollow combustion sensor tube to generate electromotive force by the difference of oxygen temperature is provided. CONSTITUTION:When the upper part of a combustion sensor tube 11 is heated by a flame, the convection current is caused becaused of the difference of temperatures produced between the inside and the outside of a combustion sensor tube 11, and the exhaust gas in the duct 10, of which oxygen concentration is low, is fed into the inner hole 11b of a combustion sensor tube 11. On the other hand, the external periphery 11a of a combustion sensor tube 11 is covered with crude gas of high oxygen concentration, which is mixed with the air in a pilot flame burner, where reaction is not yet completed. The oxygen concentration on the outside of a combustion sensor tube 11 becomes higher than the one on the inside, so that the electromotive force of a combustion sensor tube 11 turns reversely to the negative nature. Therefore, the output signal from a control circuit 20 closes a gas feed valve 3, and stops feeding of gas to a main burner and a pilot flame burner 4. |
