RAPID CONTROL OF BASIS WEIGHT FOR PAPERMAKING MACHINE AND APPARATUS THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide both an apparatus for rapidly controlling the basis weight of a paper produced in a papermaking machine and a method for the control. SOLUTION: A principal part of a stock flows through a first line 55A controlled with a thick stock valve and then flows from a stock box 53 into a headbox 1. A secondary part of the stock is deflected through a second line 56A regulated by a second valve 56B. The thick stock valve is controlled by the basis weight in a dry part and the second valve 56B responds to measured values of the basis weight of the wet stock on a wire 7. The second line 56A and the control valve 56B form a close regulation loop at a quick response time together with the measured values of the basis weight in a wet part. On the other hand, the first line 55A and the control valve 55B responsive to the measured values of the basis weight in the dry part form a rough regulation loop.