Patent ID: 6071381
Filing Date: 2000-06-06
Classification: D21F

Abstract:
A method for preventing rewetting of a web in a web former, in which water is removed from the web (W) by means of dewatering members (34) and the web (W) is formed by means of forming members and forming rolls (35) on support of a wire loop/loops (10,31), and in which method the wire loop/loops (10,31) is/are guided by means of alignment, guide and/or suction rolls (11,12,32), characterized in that, in the method, the web (W) supported by a wire (10) is passed by at least two vacuum boxes/chambers (16,17) after the last suction roll (11) or equivalent in the web former such that, in the running direction of the web (W), by means of a first vacuum box/chamber (16) moisture is sucked out of the web (W) and the wire (10) by a first vacuum (P.sub.1) and by means of a second vacuum box/chamber (17) the transport of moisture from the wire (10) back into the web (W) is prevented by a second vacuum (P.sub.2), and the first vacuum (P.sub.1) is higher than the second vacuum (P.sub.2) each of said first vacuum box/chamber (16) and said second vacuum box/chamber (17) being positioned prior to a pick up roll of said web former so that said web passes each of said first vacuum box/chamber (16) and said second vacuum box/chamber (17) prior to contacting said pick up roll.