Patent ID: 6322666
Filing Date: 2001-11-27
Classification: D21F,D21G,Y10S

Abstract:
A feedback-connected on-line regulation system for a headbox of a paper or board machine, the headbox including an inlet header into which a flow of stock suspension is passed, a slice channel having a slice opening from which a stock suspension jet is discharged, at least one flow duct through which the stock flows between the inlet header and the slice channel and actuators which affect a profile of the stock suspension jet at its discharge from the slice channel, the stock suspension jet being discharged from the slice opening in connection with at least one wire to form a web which is dried, the regulation system comprisingmeasurement means for measuring a distribution of fiber orientation in a plane of the web and generating a measurement signal based on the measured distribution of fiber orientation,a set value unit for providing a desired value for the distribution of fiber orientation in the web, anda regulator unit for receiving the measurement signal from said measurement means and the value from said set value unit and controlling the actuators of the headbox in order to attain a distribution of fiber orientation and a corresponding MD/CD ratio of tensile strength in accordance with the set value, andwherein said regulator unit is arranged to regulate the static pressure of the headbox by controlling a feed pump of said headbox based on the measurement signal.