| 摘要 |
PURPOSE:To constantly secure an excellent combustion characteristic and reduce NOx as less as possible by abruptly diffusing and mixing a high-temperature unburnt gas and secondary air. CONSTITUTION:Slit-like primary flame holes 11 are provided to cover the opening of a gaseous chamber 13 of a premixing combustion burner 12. These burner ports 11 are encircled by a first box member 15 in which secondary burner ports 14 on the upper surface. The inside of the box member 15, that, is, the inside of a combustion chamber 16, is interrupted from the atmosphere to check the inflow of secondary air into an internal flame C. Projections 17 within the first box member 15 are provided at positions which are lower than those of secondary burner ports 14 over the entire length of a longitudinal direction on both right and left sides in opposite to the inner side of a combustion chamber 16. A second box member 18 encircles the first box body 15 and has opening on both ends, projections 19 are provided at positions at the upper part of secondary burner ports 14 from both right and left sides toward the inner side. Accordingly, a high-temperature unburnt gas is diffusion-mixed with secondary air which has passed gap formed between the first box body 15 and the second box body 18.
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