Valmet Corporation

Metso Paper Inc.

Pasi Ahonen

Jaakko Kallioniemi

Juha Kaihovirta

Juha S Kinnunen

Mari Taipale

Vesa Ijas

Kari Juppi

Antti Kuhasalo

Pentti Rautiainen

Ville Korhonen

Matti Luontama

Harri Kiiskinen

Pirkko-Leena Aarnikoivu

Johan Gr&ouml;n

Oleg Timofeev

Karj Juppi

A method for manufacturing a paper or board web in which stock is fed from a headbox ( ) to a wire section ( ), in which water is removed from the web (W) and from which the web (W) is passed to a press section ( ), in which water is pressed out of the web (W) and after which the web (W) is dried in a dryer section ( ) and reeled by means of a reel-up ( ). According to the invention, additives, fillers and/or fines are fed into the stock of the surface layers of the web (W) in order to reduce the pore size distribution of the web in the surface layers so as to substantially correspond to a precoated web. The invention also relates to a paper or board machine which is characterized in that it is structured for enabling the feeding of additives, fillers and/or fines into a fiber stock such that an uncoated web substantially corresponds in its properties to a precoated web.

Method for manufacturing a paper or board web and a paper or board machine

An air impingement arrangement and method for compensating for the curling tendency of a paper or board web which is being treated. Air impingement is disposed in connection with a paper or board process or with its finishing process and extends across the width of the web ( ) running in the vicinity thereof, forming a contact-free web treatment zone, in which process the web is dried in at least one dryer unit ( ) that applies single-wire draw. In accordance with the invention, air impingement directed at the web ( ) is produced by the air impingement arrangement ( ) in the web treatment zone, said air impingement including, one following after the other, at least one hot blowing with air and at least one cold blowing with air. The invention also relates to a paper or board machine provided with this kind of air impingement arrangement.

Method and arrangement of impingement for blowing compensation of a tendency of curling of a paper board web to be treated as well as a paper or board machine

The invention concerns a method for manufacture of paper, most appropriately for porous paper for color powder printing. In the method paper is manufactured by means of a paper machine. In the method the paper stock is fed out of the headbox ( ) into the wire part ( ), in which wire part ( ) water is drained out of the paper web in both directions. In the method the paper web (W) is passed from the wire part ( ) into the press section ( ) in order to press water out of the paper web (W), and after the press section ( ), the paper web (W) is dried in the dryer section ( ) and coated/pigmented in the coating section ( ), dried in an after-dryer section ( ) and calendered in a calender ( ), and reeled in a reel-up ( ). The paper web (W) is made of layers in the Z-direction so that the desired distributions of additives and fillers are obtained in the different layers in the Z-direction of the paper web (W), and the paper web (W) is calendered in at least one calendering nip, which maintains or at least substantially retains the porosity of the web preceding the calendering. The invention also concerns a paper machine, most appropriately for manufacture of glossy and porous paper for color powder based printing. The paper machine comprises a headbox ( ), a wire part ( ), a press section ( ), a dryer section ( ), a coating section ( ), an after-dryer section ( ), a calender ( ), and a reel-up ( ). The headbox ( ) and the wire part ( ) have been formed so that the desired layers with different compositions in the Z-direction are provided in the paper, and the calender ( ) is a calender device that maintains or at least substantially retains the porosity of the paper web (W) preceding the calendering.

Method for manufacture of paper and a paper machine

A method and arrangement for drying a paper to be surface-treated, in particular fine paper, in an after-dryer in a paper machine. The paper web is first dried in a forward dryer section of the paper machine by one or more groups with single-wire draw that are open downward on support of a drying wire, the paper web is then finished in a finishing section, e.g., surface-sized or coated, and thereafter, the paper web is dried by an upwardly open inverted group with single-wire draw. In the inverted group with single-wire draw, the tendency of curling formed in the paper web in the forward dryer section can be substantially eliminated and/or compensated for. In the alternative, to eliminate or compensate for the tendency of curling formed in the paper web in the forward dryer section, hot moist air may be fed into certain locations into connection with the dryer groups in an after-dryer in order to restrain the evaporation, or hot dry air may be fed in order to promote the evaporation from the side of the web that is desirable in view of the control of curling.

After-dryer in 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%.

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.

An after-dryer and method for drying a surface-treated paper web in an after-dryer of a paper machine in which the web is first finished in a finishing section, i.e., surface-sized or coated, by a finishing device and then dried. In the after-dryer, the paper web is dried in at least one dryer group that makes use of single-wire draw and at the same time, the paper web is dried by an impingement-drying equipment arranged in connection with at least one cylinder or roll in the single-wire dryer group.

Growing community of inventors

Jyväskylä, Finland

Pasi Ahonen