| 摘要 |
<p>An apparatus for testing the air-permeability of lengths of textiles, in particular of largely incompressible paper-machine felts or strainers, has a measuring fork that carries a pair of pipe stubs one of which is displaceable relative to the other for clamping the length of material between the pipe stubs. The other pipe stub is connected by an air pipe passing to a motor-driven exhauster. Provision is made in the air pipe for at least one control means to set the volumetric flow, at least one vacuum gauge, preferably a first differentialpressure meter and at least one air volumeter or airflow rate meter. The pipe stub connected to the air pipe (25) is designed as a double pipe stub (12,13) with coaxial inner and outer pipe parts (17,18 and 19,20). The air pipe (25) is connected to the inner pipe part (19) and the outer pipe part (20) is connected to a parallel pipe (28) passing between the airflow rate meter (27) and the exhauster (26) and issuing into the air pipe(25). A vacuum-setting control valve (29) is mounted in the parallel pipe (28), and the outer pipe part (20) and the inner pipe part (19) of the immobile double pipe stub (13) are connected to a second differential pressure meter.</p> |
