Process and apparatus for dewatering a fibrous web

摘要

In a process to de-water a web (12) feed of paper or carton, the web passes through a de-watering zone (E) in which the fluid is displaced by pressurized gas (14). The de-watering zone is esp. sub-divided into two or more zones (E1, E2, E3) in each of which the pressure is set individually. The assembly is incorporated within a prior art de-watering press with a sequence of drums. Also claimed is a commensurate de-watering assembly in which the web is transported together with a supporting membrane (16) through a de-watering zone in which the web is exposed to the pressurized gas. As seen in the direction of web travel (L) gas pressure in the first sector (E1) is lower than in the second sector (E2). Pressure in the third sector (E3) is lower than in the second sector. Also claimed is a process to make the supporting membrane (16).