New Generation of Press Sections, Without Open Draws, 1999 Papermakers Conference Proceedings

Juha Kivimaa
While the introduction of the shoe press for printing and writing paper machines has significantly improved the productivity, the press section still sets limits for production in many cases. The open draw after the center roll of a press section is today the most restricting factor for further production speed increases.

Up to these days the most effective press section concept for high speed machine consists of a compact press with three press nips, where at least the last press nip is a shoe press. After the last press the paper is transferred from the smooth center roll in a short open draw to the dryer section. With the stresses in such an open draw the web strength limits the machine speeds.

The new generation of press concepts are now available for printing and writing grades. The closed draw press concept has been proven to run with low press draw. For fine paper a closed draw press concept has already been introduced to a production machine. In this paper there will be results from this production machine too.

The closed draw press concept operates with full width automatic sheet threading, thus improving operators safety and cutting down threading time to close to absolute minimum. The further development of this press section has led to different concept options, which suite the different demands of rebuilds, new machines or various paper grades. By applying new design principles this new press concept will set new standards for user friendliness and maintainability.