| 摘要 |
In the production of, for example, asbestos cement boards, a felt belt is guided through a deposition box in which an asbestos cement slurry is disposed. A mat is deposited from the slurry onto one side of the felt belt and the mat is sucked onto the felt belt, for which purpose a suction device is present on the other side of the felt belt. In order now to obtain boards of uniform thickness and strength, a cylindrical screen/couching roll arrangement (18, 19) which compacts and dewaters the deposited mat is disposed downstream of the deposition box (6). The suction of the mat takes place by a subatmospheric pressure which is locally variable in the longitudinal direction and/or lateral direction of the felt belt. To this end the suction box is subdivided into individual boxes (8, 9) which are arranged one behind the other in the conveying direction and, if appropriate, one next to the other across the felt belt width. Preferably an adjustable cover screen (10) is arranged in the deposition box (6), such that a flow channel (11) for the asbestos cement slurry is produced between said cover screen (10) and the felt belt (3). This flow channel promotes the desired irregular orientation and uniform density of the asbestos fibres in the mat. <IMAGE> |
