| 摘要 |
A device or method for monitoring the gas-permeability of a sheet material is disclosed. The device comprises a first gas-flow chamber having an inlet, which, during operation of the device is closed by the sheet material extending across the inlet. A second flow chamber has an outlet by which a gaseous medium can be directed towards the sheet material with a leakage path whereby a significantly greater proportion, suitably 90%, of the gas-flow in the second flow chamber is permitted to leak to the atmosphere. This leakage path is provided by spacing the gas outlet of the second chamber from the position in which the sheet material extends across the gas inlet of the first chamber. A measurement means, preferably a pressure transducer is connected across a low-impedance laminar-flow device.
|
