| 摘要 |
A paper web (1) of low grammage is formed on a fabric (3) in the wet end of a paper machine, picked up from the fabric (3) by pick-up means (9, 11), and after the picking-up is conveyed to and through the drying section (13, 15) of the paper machine. To reduce the energy consumption for the drying in the drying section the web (1) is divided by means of edge cutters (25) into a trimmed web (1a) and couch trimmings (1b) while it is being conveyed on the fabric (3). Thereafter the trimmings (1b) are retained on the fabric (3) by means of suction means (27) when the trimmed web (1a) is picked up from the fabric (3) to be conveyed to and through the drying section (13, 15), and finally the retained trimmings (1b) are removed from the fabric (3) by means of a wire roll (41) located externally of the fabric loop. Said suction means comprise a suction box (27) having a suction slot (31) of a length that substantially corresponds to the width of the couch trimmings (1b), and the suction box (27) is located some few millimetres (A) below the plane (39) of the fabric (3) and is able to develop a suction force that is sufficient to displace the fabric edge portion, which carries the couch trimmings (1b), from the plane (39) of the fabric in the area of the picking-up of the trimmed web (1a) from the fabric (3). Hereby you avoid on one hand web breaks and similar problems, and on the other hand that the couch trimmings (1b) are picked up from the fabric (3) together with the trimmed web (1a). |
