| 摘要 |
A fluid flow control device comprises a duct having a masking membrane arranged within the duct for movement between a first position, in which it closes the duct, and a second position in which it allows fluid to pass through the duct. The masking member is in the form of a deformable membrane disposed across the duct, the membrane having two portions having bellows-type folds and opposed end elements defining between them a flow aperture, which can be opened or closed to adjust the fluid flow.
|
