| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance a heat retaining property in a connection part of the branch duct and main duct of a flexible duct.SOLUTION: Between a main duct 10 and a branch duct 20 of a flexible duct 1, a duct connection part connecting a first gas flow passage 19 of the main duct 10 and a second gas flow passage 29 of the branch duct 20 is interposed. The duct connection 30 has an annular connection heat insulation layer 33 comprising grass wool different from those of a first heat insulation layer 13 of the main duct 10 and a second heat insulation layer 23 of the branch duct 20.</p> |
