| 摘要 |
<p>PURPOSE:To suppress instability of secondary flame and elongation of the flame by providing a first rectangular parallelepipedic box having projections below the secondary flame port, a second box, which surrounds the first box and has projections at a position higher than said secondary flame port, and porous material, which is made of transition metal and is attached to the outer wall of the second box in the neighborhood of its top surface opening. CONSTITUTION:When the combustion rate starts to be throttled, the formation of a secondary flame D on a secondary flame port 13 becomes no more possible and the secondary flame D is formed at projections 15. When the combustion rate is further reduced so as to realize the condition that the formation of the secondary flame D at the projections 15 is not possible, secondary air diffuses to the neighborhood of primary flame ports 14 so as to form premixed flames on the primary flame ports 14. Because the projections 17 of a second box 16 change the flow of the secondary air, the secondary flame D formed on the secondary flame port 13 is turned into a short flame and at the same time formed stable. A lath 18 is heated by combustion gas up to 400-600 deg.C and thermally dissociates NO2 into NO.</p> |
