| 摘要 |
The present invention concerns a method in a paper machine for the measurement of air penetrability or permeability of fabrics penetrable by air, in particular of a wire or felt. In the method, the fabric penetrable by air such as a wire is passed over at least one roll, where a positive pressure is formed at an inlet side of the fabric with respect to the roll when the fabric runs and in an inlet nip formed between the moving fabric and a face of the roll, and a negative pressure is formed at an outlet side of the moving fabric with respect to the roll in an outlet nip formed between the moving fabric and the roll face. The positive pressure and negative pressure depend up on the permeability of the fabric penetrable by air. According to the method, at least one device is mounted below the fabric penetrable by air such as a wire, this device being sealed relative to the moving roll face so that an at least partially closed pressure space is formed between the device, the roll face, and the fabric. While the fabric penetrable by air such as the wire moves, the pressure is measured out of the pressure space and the permeability of the fabric penetrable by air is calculated from the measured pressure value. The present invention also concerns a device for carrying out this method. |
