Drying assembly

摘要

The support belt (2) takes over the fibrous web (1) from a guide belt (9) before and/or during wrapping of the guide roller (3). The guide roller (3) has two separate suction zones (11, 12), each associated with a support belt (2) wrapping zone. The guide- and return rollers are arranged in a vertical, or slightly inclined line. The web (1) is led over the heated drying cylinder (8) in a contact drying zone following the impingement section. The guide- and return rollers (3, 4) are preferably arranged under the drying cylinder (8). The web is blown with hot air before and/or after the return roller. Support rollers (6) are located in the space between guide- and return rollers. The return roller is a suction roller. The pressure reduction exceeds that of the guide roller and is 500-3000 Pa. The pressure reduction in the first suction zone (11) of the guide roller (3) is greater than in the second suction zone (12). Further details of pressure reductions are disclosed. No suction is applied in sections between the guide- and return rollers. Sections of the guide roller not in contact with the support belt, include covers inside or outside the roller casing. The guide roller has a perforated casing and a suction box inside, for the first suction zone (11). There is a similar arrangement for the second suction zone, with a suction box inside or outside the casing. Further mechanical details of suction zones and variant arrangements are provided in accordance with the foregoing principles.