device and method for online control of the faserrichtung in a faservlies

摘要

On-line control device comprises former(s) with head box(es), fiber direction meter, actuators, and control unit. The head box is arranged for delivering a stock. The former is made into the fiber web, through a slice including lips. The lips are movable in relation to each other and define a discharge opening. The fiber direction meter is downstream the former for measuring the fiber direction of the fiber web. On-line control device comprises former(s) (2) with head box(es) (3), fiber direction meter (12), actuators (14), and control unit (13). The head box is arranged for delivering a stock. The former is made into the fiber web (8), through a slice (7) including lips (9, 10). The lips are movable in relation to each other and define a discharge opening (11). The fiber direction meter is downstream the former for measuring the fiber direction of the fiber web. The actuators are along the lips for regulating the discharge opening locally as a response to individual control signals. Each actuator is a function of measured fiber direction values. The control unit receives the measured fiber direction values from the fiber direction meter, calculates the control signals, and transmits the control signals to the actuators. The control unit identifies an array of fiber direction values of the measured fiber direction values. The fiber direction values of the array originates from positions in the cross direction of the fiber web corresponding to the position of the actuators. The control unit is arranged for comparing the identified array of fiber direction values with array of fiber direction values by calculating array of error values. The control unit is arranged for calculating the control signal for each actuator as a function of the error values in accordance with the equation stating that signal is equal to the product of error values and constants plus the summation of the difference of the error values multiply by the constant as it approaches integral number. An Independent claim is included for on-line control method comprising measuring the fiber direction of the fiber web by fiber direction meter arranged downstream the former, calculating and transmitting individual control signals, identifying an array of the fiber direction values, and comparing the identified array of the fiber direction values with an array of fiber direction.