Valmet Corporation

Vesa Ijas

Pasi Ahonen

Jaakko Kallioniemi

Kari Juppi

Harri Kuosa

Karj Juppi

Jouko Meronen

Markku Kirvesmaki

Risto Vainio

A method in a dryer section of a paper or board machine for controlling curl of paper, in which steam treatment and/or moistening of the paper web is/are employed. The operations carried out in order to control the curl of the paper web are carried out in a number of stages when the web temperature is, during at least one stage, lower than 85.degree. C., preferably lower than 75.degree. C., and when the dry solids content of the web is in the range of K1-K2, wherein K1 is the ultimate dry solids content of the web -7% and K2 is the ultimate dry solids content +3%.

Method for controlling curl of paper in a dryer section of a paper

A method in a dryer section of a paper or board machine for controlling curl of paper, in which steam treatment and/or moistening of the paper web is/are employed. The operations carried out in order to control the curl of the paper web are carried out in a number of stages when the web temperature is, during at least one stage, lower than 85.degree. C., preferably lower than 75.degree. C., and when the dry solids content of the web is in the range of K1-K2, wherein K1 is the ultimate dry solids content of the web -7% and K2 is the ultimate dry solids content +3%. The paper or board machine includes at least a headbox, a former, a press, and a dryer section in steam boxes or moistening devices are employed for control of the curl. There are at least two curl regulation devices to enable regulation of the curl in a number of stages, and/or the curl regulation devices are arranged to operate in an area in which the web temperature is, during at least one stage lower than 85.degree. C., preferably lower than 75.degree. C., and the dry solids content of the web is in a range of K1-K2, wherein K1 and K2 are as defined above.

A paper machine roll, in particular for a soft calender or supercalender, which includes a metal frame, roll ends, and shafts. The frame is coated with a polymer coating over at least a middle area or central region thereof while lateral regions may optionally remain uncoated. In order to equalize a difference in temperature between the roll ends and the optionally non-coated lateral regions of the metal frame, on one hand, and the coated central region area of the roll, on the other hand, an arrangement for equalizing the difference in temperature is provided by heating the roll ends and the optionally non-coated lateral regions of the metal frame.

Paper machine roll with heated ends in a soft calender or supercalender

Growing community of inventors

Viiala, Finland

Vesa Ijas