| 摘要 |
An apparatus for testing the permeability of porous web materials. The porous web 12 is placed against a surface of a test head 10 of the apparatus. The test head 10 contains at least one aperture 28 and a vacuum source 87 connected to the test head 10 causes air to be drawn through the web 12 and then through the aperture 28. The test head 10 also includes at least one static port 32 that communicates with the aperture 28. The static port 32 is located very close to the web 12 and measures the static pressure within the aperture 28 before it leaves the aperture 28. A pressure transducer 46 is connected to the static port 32 and provides a measurement of the pressure drop across the web 12. If the volumetric flow rate of air through the web 12 is kept constant, the pressure transducer 46 output 52 is representative of the permeability of the web 12. If the pressure differential across the web 12 is kept constant, measurement of the volumetric flow rate of air through the web 12 will be representative of the permeability of the web 12.
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