Metso Paper Inc.

Pertti K Heikkilä

Samppa J Salminen

Antti Poikolainen

Ari Puurtinen

Richard Solin

Johan Lindholm

Erkka Nieminen

Veli-Matti Vainio

Markku Laitonen

Erkki Kärkkäinen

The object of the invention is an end part () of an air dryer, the air dryer being applicable for drying a pulp web, such as a cellulose web or the like. The end part comprises a fan tower (), and a roll tower in which a number of turn roll () are arranged mainly on top of each other in order to turn the travelling direction of the pulp web in the air dryer, the longitudinal axis of the roll. towers being parallel, and a fan tower arranged at a distance from the roll tower, adjacent to it, comprising a number of fans arranged on top of each other, a single fan being arranged to blow heated air as drying air to a dryer group. The end part further comprises one or more centrifugal fans () arranged in the direct vicinity or the roll tower, and a number of end drying means () arranged between the roll tower and the dryer group of&#x2014;the fan of the fan tower, to which end drying means drying air is supplied with said centrifugal fan or fans. A further object of the invention is also a method in the end part of an air dryer, an air dryer and use of a centrifugal fan.

End part of an air dryer, air dryer, method in the end part of an air dryer and use of fan

A paper or board machine has a fabric () that is adapted mobile as well as rolls (') arranged to support the fabric (). The fabric () is tensioned by changing the position of one roll (&#x2032;) of the rolls (&#x2032;). Correspondingly, the fabric () is guided by changing the alignment of one roll (&#x2032;) of the said rolls (&#x2032;). Surprisingly the fabric () is both tensioned and guided by changing the alignment and position of only one and the same roll (&#x2032;). In addition, the wrap angle of the fabric () at this roll (&#x2032;) is set higher than 30&#xb0;.

Method, arrangement and equipment for tensioning and guiding a fabric in a paper or board machine

At the end of the twin wire zone of a paper machine former, a suction box () inside the upper wire loop () has a curved lid (') opposite a roll () within the lower wire loop (). The lid is curved in a run situation so the tension of the upper wire () reduces the normal force between the wire () and the lid (&#x2032;) caused by the underpressure of the suction box. The underpressure keeps the web mainly off from the roll () and the lower wire () while being adhered to the underside of the upper wire () and conforming to the curved shape of the lids. Members (&#x2032;) are provided for making the web follow the lower wire () in a break situation for conducting it to the broke handling system.

Arrangement in the wet end of a paper machine

Growing community of inventors

Laukaa, Finland

Pertti K Heikkilä