| 摘要 |
<p>Modern Yankee machines for thin paper qualities give the possibilities at present to approach machine speed of 200 m/min with a specific weight of about 17 g/m2. The machine consists of a forming section (often called a twin wire former), a web transfer section (in which the formed sheet is transferred to the press felt), and a suction press roll over which the press felt with the web is turned so that the web presses against the warm Yankee cylinder. In order to increase line speed without encountering problems, the web is now formed between a felt (2) - or a press fabric - and a forming fabric (3). The forming unit, consisting of the felt and fabric is placed in such a position in relation to the press roll (8) that the web (10), when it is separated from the forming fabric (3), is transported by the felt (2) and can be led into a press nip against a Yankee cylinder (7) surface along a straight path.</p> |
