| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce resistance against fluid and generation of noise of bellows provided on a duct. SOLUTION: The bellows 2, 3, and 4 provided on the duct 1 are formed in a spiral shape so that the flow resistance of the bellows against the fluid running in the duct is reduced and the generation of the noise by the flow of the fluid is also reduced. An angle of the spiral with respect to a central axis of the duct is determined in consideration of advantages in reduction of the resistance against the flow of the fluid and deterioration of the bending property of the bellows.</p> |
