| 摘要 |
In order to improve the paper forming in the manufacture of a web of paper, especially newsprint paper, in a roll- type double wire former, the position of the fine fraction in the direction of thickness of the paper and the maximum, local concentration of the fine fraction are controlled by dehydration first being effected unilaterally outwards from the forming roll 5, which is plane-surfaced, and out through the outer wire 1. This dehydration is not pursued to the point where the dry line is already reached on the forming roll 5, but rather the dry content when the wires 1 and 3 leave the forming roll 5 is around 4-5%. Dehydration is next effected unilaterally inwards in the opposite direction through the inner wire 3 towards curved suction boxes 91, 92 and 93 having a radius of curvature substantially greater than that of the roll 5. The suction boxes operate on increasing underpressure in the running direction of the wires 1 and 3 and the last of them sucks through air so that the outer wire 1 is emptied of water before being separated, expediently on a plane-surfaced parting roll 25, from the paper web 11 and inner wire 3, wherein a small parting angleβ, less than 5 degrees, between the wires 1 and 3 is used. <IMAGE> |
