| 摘要 |
<p>The double tube for discharging combustion gases from gas fired equipment through the wall of a building and for entry of fresh air. It has an intermediate tube (5) between the discharge tube (6) and a lining tube (1) through the wall. At the discharge end is a resilient collar (2) between the intermediate and lining tubes. ]This collar has cut-outs (3) to engage joints on the outside of the intermediate tube. The latter is split, and these joints are at their connection points. Further inwards, the intermediate tube has a groove around it for a sealing ring (10), and furthest in are corrugated blades (8). Air enters between the inner tube (6) and the intermediate tube (5).</p> |
