| 摘要 |
A tubular body 10 is adapted for attachment to the outlet aperture of an exhaust gas flue from the boiler and the internal walls 13, 14, 15 and 16 define a flue gas path the cross-sectional area of which alternately reduces and increases along the length of the path, to the outlet aperture 17 of the path. The outlet aperture 17 may be of a smaller cross-sectional area than the inlet aperture 11. The outlet aperture may be fitted with a cowl. The internal walls may take various forms (Figs. 2 and 3). <IMAGE> |
