Metso Paper Inc.

Valmet Technologies Oy

Valmet Technologies, Inc.

Matti Lares

Pekka Koivukunnas

Kari Holopainen

Mika Viljanmaa

Pekka Linnonmaa

Juha Lipponen

Heikki Kettunen

Hans Sundqvist

Seppo Luomi

Juha Kivimaa

Risto Sutti

Mikko Tani

Timo Torvi

Richard Solin

Tapio Mäenpää

Kari Hasanen

Mika Leino

Matti Tervonen

Henri Vaittinen

Kalle Hasu

Eveliina Karjala

Juha Kovanen

Petri Lewandowski

Antti MÄNTYNEN

Sampo Immonen

Sari Behm

Mikko MAJAMÄKI

Toni Tikka

Pekka Koivukannas

Pietikäinen Reijo

Markku Kyttsönen

Nissinen Vilho

A method for pre-calendering a board web is provided and comprises passing the board web in a pre-calendering process through at least one hard nip, formed by a metal roll and a counter roll, and through at least one long nip, formed by a thermo roll and a long-nip roll or a long-nip belt assembly. The surface of the board web is moistened with water prior to the board web passing through the at least one hard nip.

Method of pre-calendering a board web

The invention relates to a method for controlling a surface quality variable () in one or more fiber webs () in a shoe calender () comprising one or more calender nips. In each calender nip of the shoe calender, the overall loading pressure of the shoe element () and the loading pressure difference between the leading edge (') and the trailing edge (&#x2033;) of the shoe element are controlled so as to achieve minimum difference between the determined values (&#x2033;) for the surface quality variables of the fiber web and the set values (&#x2032;) for the same quality variables after the shoe calender.

Method for controlling one or more surface quality variables of a fiber web in a shoe calender

A method and an arrangement for manufacturing calendered paper or board particularly in the on-line manufacturing method. In the method, a base web is formed from a mixture of water and pulp supplied from the headbox and the web is dried by removing water over the press section and over the dryer section by heating. The formed web is calendered at least once to modify the surface on at least one of its sides. Before calendering the cross-direction thickness profile of the web is standardized and calendering is carried out by means of a long-nip calender, whereby good surface quality is obtained without losing the bulk or stiffness of the web.

Method and apparatus for producing calendered paper or board

Higher-gloss paper grades, in particular paper grades with a Hunter gloss % above 40, are produced in an arrangement having pairs of calendering units () disposed in the machine direction one after the other and apart from one another, which pairs are each formed of separate and different calendering units () and in each of which the nip load in the latter calendering unit () is higher than the nip load in the preceding calendering unit (). Advantageously, the calendering unit () placed first in the machine direction is an on-line long-nip calendering unit () and the calendering unit () placed after that in the machine direction is an on-line or off-line supercalender.

Calendering arrangement for a paper machine

A long nip (N) shoe calender formed of a shoe roll () and a thermo roll () is used in calendering, with a nip dwell time which is over 10 ms, advantageously over 20 ms. The nip pressure is below 3 MPa, advantageously below 1 MPa, and a surface temperature of the thermo roll () is over 200&#xb0; C., advantageously over 250&#xb0; C. The board web (W) surface to be pressed against the thermo roll () is moisturized before the nip.

Method for calendering a board web

A method and an arrangement for surface treatment of a paper and/or board web (W) formed of a yankee cylinder ( ) and a calendering unit ( ) placed one after the other in the machine direction, by means of which the web (W) is first glazed and dried and after that immediately calendered.

Method and arrangement for surface treatment of a paper and/or board web

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Tuusula, Finland

Matti Lares