Patent ID: 6860033

Claim:
A method for minimizing tension variation in a paper web induced by drying of the web in a paper machine having a dryer section with dryer groups and draws between said dryer groups, the method comprising the steps of: measuring and determining longitudinal strain components of the web, including reversible elastic strain, permanent plastic strain and frozen-in strain relievable with water; and minimizing variation of said longitudinal strain components by correcting the moisture content of the paper web in the dryer section of the paper machine and/or by optimizing the draws between dryer groups in the dryer section, wherein in an area of the beginning of the dryer section, when the dry solids content of the web is below 60 percent, the moisture content of the paper web is affected by means of actuators which correct the moisture content of the web and by which the web is moisturized and/or dried, and that the operation of said moisture-correcting actuators is controlled by measuring the moisture content of the web in the dryer section in the running direction of the web after the moisture-correcting actuators.