| 摘要 |
The invention concerns a dryer section of a paper machine, which consists of several groups with single-wire draw that include a drying wire (22, 32, 62, 72, 82, 92), inside whose loop there is a number of reversing cylinders (21, 61, 71, 81, 91). In the gaps between them there are contact drying cylinders (20, 60, 60A, 70, 70A, 80, 80A, 80B, 80C, 90, 90A) against whose heated faces the drying wire (22, 32, 62, 72, 82, 92) presses the paper web (W) into direct contact. In addition to normal contact drying cylinders (20, 60, 70, 80, 90), one or several contact drying cylinders (60a, 70A, 80A, 80B, 80C, 90A) with a larger diameter, the diameter being D4 > 2200 mm and, as a rule, in the range of D4 APPROX 2200... 3600 mm, is/are used in one or several groups (R6, R7, R8; Rn) with single-wire draw that are open towards the bottom. An impingement-drying/ventilation hood (66; 76; 86; 86A; 96) is fitted above said contact drying cylinders (60A, 70A, 80A, 80B, 80C, 90A) with larger diameter D4, which hood extends on a large sector above said contact drying cylinder and above the drying wire (22, 32, 62, 72, 82, 92) and the web (W) running over the cylinder. An impingement-drying/ventilation effect is applied to the drying wire (22, 32, 62, 72, 82, 92) through impingement-drying/ventilation hoods (66; 76; 86; 86A; 96) on said wide sector, by means of which effect the moist boundary layer in contact with the drying wire (22, 32, 62, 72, 82, 92) is disintegrated and drying is promoted from the side of the face of the web opposite to the web (W) face that is placed against the contact drying cylinders (60A, 70A, 80A, 80B, 80C, 90A). |
