Patent ID: 6120645
Filing Date: 2000-09-19
Classification: D21F,Y10S

Abstract:
A process for operating a press section for producing a fibrous web, comprising:forming a nip that is elongated in a web travel direction, the nip including an inlet zone having an inlet beginning and an inlet end, a main pressing zone having a main beginning and a main end, and an outlet zone;determining a pressure to be applied in the main pressing zone;selecting a pressure gradient in the main pressing zone as a function of a dry matter content of the fibrous web entering the elongated nip, wherein the pressure gradient is related to the selected pressure to be applied in the main pressing zone;guiding the fibrous web in a web travel direction through the elongated nip;setting the selected pressure gradient;wherein the selecting of the pressure gradient, when the dry content of the web entering the nip is in an average condition or a high condition, comprises:setting a maximum pressure to be applied at the main end of the nip; andproducing the pressure gradient from a range of approximately 0.01.cndot.p.sub.max /cm to approximately 0.08.cndot.p.sub.max /cm, where p.sub.max represents the determined maximum pressure to be applied and is in the range of approximately 20 bar to 100 bar.