| 摘要 |
A nozzle in a descending discharge duct for hot flue gases has a tubular body of hourglass shape partly obstructed by a vertically movable frustoconical insert which defines a narrow, downwardly diverging annular channel with the lower part of the body lying below its waist. The upwardly converging top of the insert, projecting partly above the waist, is coated or clad with a refractory layer and is removable for replacement of that layer. |
