Patent ID: 6325881
Filing Date: 2001-12-04
Classification: B31F,Y10T

Abstract:
A method for controlling a phase shift between a corrugated configuration of a first core paper web and a corrugated configuration of a second core paper web when the second core paper web is adhered onto the first core paper web, said first core paper web having previously been adhered onto a liner to form a corrugated fiberboard sheet, so as to form a corrugated fiberboard sheet with laminated multi-layer core paper as a final product, said method comprising the steps of:(a) measuring a series of phase shifts between the corrugated configuration of the first core paper web and the corrugated configuration of the second core paper web at periodic intervals;(b) obtaining a preceding sheet distortion quantity corresponding to a precedingly measured phase shift value and a current sheet distortion quantity corresponding to a currently measured phase shift value during said step (a);(c) estimating a next sheet distortion quantity corresponding to a next phase shift to be obtained by a succeeding measurement, based on the preceding sheet distortion quantity and the current sheet distortion quantity obtained in said step (b);(d) calculating an amount of change to be made in a tension of the corrugated fiberboard sheet so as to compensate the next phase shift, based on the next sheet distortion quantity estimated in said step (c); and(e) adjusting the tension of the corrugated fiberboard sheet during an interval between a current measurement and a succeeding measurement based on the amount of change calculated in said step (d) to thereby control the phase shift between the corrugated configuration of the first core paper web and the corrugated configuration of the second core paper web,wherein in said step (c), the next sheet distortion quantity corresponding to the next phase shift .delta..sub.3 is estimated by 2 .DELTA..epsilon.*.sub.1 -.DELTA..epsilon..sub.1, where .DELTA..epsilon..sub.1, is the preceding sheet distortion quantity corresponding to the precedingly measured phase shift value .delta..sub.1, and .DELTA..epsilon.*.sub.1 is the current sheet distortion quantity corresponding to the currently measured phase: shift value .delta..sub.2, andin said step (d), the amount of change .DELTA.T.sub.1 is calculated by (2.DELTA..epsilon.*.sub.1 -.DELTA..epsilon..sub.1)/K, where K is a sheet distortion quantity per unit tension.