Valmet Corporation

Metso Paper Inc.

Jaakko Kallioniemi

Pasi Ahonen

Kari Juppi

Vesa Ijas

Pekka Koivukunnas

Antti Komulainen

Juha Lipponen

Juha Kaihovirta

Petri Norri

Ville Korhonen

Matti Luontama

Karj Juppi

Laurie Coulson

The invention concerns a dryer section, comprising at least one dryer group (R) that makes use of single-wire draw and/or twin-wire draw and at least one suction roll ( ) with which the web (W) to be dried is in direct contact. The surface construction of the suction roll ( ) is of a fine structure so that the web (W) can be passed to run over the suction roll ( ) in direct contact with the roll so that the web (W) is not damaged.

Dryer section

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 dry end of a paper machine and a method for drying paper in which a paper web to be dried is passed from a press section of the paper machine into a forward dryer section including only single-wire groups with normal single-wire draw. The web is dried from the side of its bottom face in the dryer groups in the forward dryer section. From the forward dryer section, the web is passed into a finishing section in which the web is coated/surface-sized by a coating/surface-sizing device and then dried in an after-dryer by passing through at least one dryer group that applies a normal single-wire draw. Thereafter, the web is calendered and passed to a reeling station. Curling of the web is controlled by the operation or construction of components and/or by assemblies and combinations formed out of these components provided in connection with the forward dryer section and/or the finishing section.

Method for drying paper and a dry end of a paper machine

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.

Growing community of inventors

Muurame, Finland

Jaakko Kallioniemi