| 摘要 |
A pressing method and apparatus for dewatering a fibre web, such as a paper or cardboard web, in a paper machine press section including two press rolls through which the web is conducted carried on either a single fabric or interposed between a pair of fabrics. The web is pre-pressed in a pre-pressing zone located in the throat region between the press rolls. The pre-pressing pressure is applied to the web through the mediation of a substantially impermeable band which passes through the press nip in overlying relationship with the web as the latter is conducted over a sector of one of the press rolls. After the pre-pressing step, the web is immediately conducted through the zone of the press nip, the pressing of the web which takes place in the press nip determining the dry matter content of the web subsequent thereto. The pre-pressing zone immediately precedes the zone of the press nip so that the pre-pressing and nip zones together in combination constitute a pressing zone. The peak pressing pressure present in the press nip zone is greater than the pressure in the preceding pre-pressing zone. |
