Method and apparatus in moistening of a web
AssigneeMetso Paper, Inc.
InventorsAntti Heikkinen, Mikko Tani
Life of this patent
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Abstract
In the method in moistening of a web, water is applied with a wetting device (2) in a predetermined point on the surface of a paper web (W) or the like passing by the point, and the web is thereafter passed to a calender (C). The liquid is applied at such an early stage that before the surface treatment, the fibres exposed to wetting in the paper web (W) or the like have the time to absorb it at least 80% of the amount of liquid they are capable of absorbing. The distance travelled by the web between the drying section and the calender is increased with rolls (1) which guide the web (W) along a winding path.
Claims29
A method for the moistening of a paper web in a paper or paperboard making process, comprising the steps of:
- applying a liquid to a surface of said paper web while said paper web is passing a predetermined point in said process;
- passing said paper web to a surface treatment process in a calender having at least four nips;
- providing a sufficient amount of absorption run time of said paper web between said applying of said liquid to said paper web and said passing of said paper web to said surface treatment process such that at least 80% of an amount of said liquid which is absorbable by said paper web is absorbed;
- providing a paper web guiding system comprising a plurality of paper web guiding members structured and arranged between said point of applying said liquid to said paper web and said passing of said paper web to said surface treatment process;
- and
- adjusting said absorption run time of said paper web by changing a location of at least one of said paper web guiding members.
An apparatus for the moistening of a paper web in a paper or paperboard machine, comprising:
- a calender having at least four nips structured and arranged for treating said paper web;
- at least one web wetting device, for adding a liquid to said paper web, structured and arranged before said calender in a machine running direction;
- wherein said at least one web wetting device is located a predetermined web running distance before said calender such that said liquid added to said paper web has sufficient time for at least 80% of the total amount of said liquid which said paper web can absorb is absorbed before reaching said;
- and
- at least three rolls structured and arranged between said calender and said at least one wetting device, said at least three rolls comprising a first roll and a last roll and being structured and arranged to guide said paper web along a winding path having an overall length between the first roll and the last roll, and at least one of said at least three rolls being structured and arranged to be changeable to another location such that the overall length of the path between the first roll and the last roll is changed to effect in a web running distance.
Dependencies are inferred from the claim text.