The strength of periodic press section marks in paper

摘要

The degree of felt marking depends on various parameters,including felt construction,sheet furnish,and pressing conditions.A new technique can predict the degree of felt marking quantitatively.Pressure-sensitive material is used to measure the distribution of loads arising from the fabric's structure when the applied load is constant.The results are analyzed with an image analysis method involving fast Fourier transform (FFT) techniques.This information can be used in light of a pressing theory to estimate the effects that various pressing conditions have on the sheet.The technique was used to study the effects of ingoing moisture ratio,sheet weight,and furnish composition.Analyses showed that marking is always more likely to occur in downstream presses.Surprisingly,higher pressure in the press can lead to less marking.