Valmet Ab

Valmet Corporation

Valmet Pescia Srl

Fabrizio Bartolini

Marco Capitani

The present invention relates to systems and methods for calculating the additional local stretching of a moving web through a converting process in order, during rewinding, to find the position of defects in the web that were identified during winding and stopping the web with the web defect close to or at a defect correcting station. The method comprises, during rewinding of the web, the steps of detecting position markers (PM(n)) applied during winding of the web (), measuring the distance between the position markers, calculating the additional local stretching between the position markers occurring during rewinding, applying the calculated additional local stretching to the known position of a following web defect to determine an estimated position of that web defect in the rewinding web. A method for correcting a web defect comprises the step of subsequently stopping the web with the web defect at, or close to, a defect repairing station ().

System and methods for the calculation of additional local stretching in a web

A device and method of winding a web (W) of tissue paper or a non-woven material onto spools () to form a succession of web reels () on the spools () wherein the force in the winding nip () is measured and, as the diameter of the web reel () grows, the spool () on which the web reel () is wound is moved during winding along a horizontal plane such that, in the horizontal direction, the distance between the first supporting drum () and the spool () increases, and the second supporting drum () is moved vertically downwards to match the increasing size of the web reel () while maintaining contact with the web reel () to such an extent that a nip force between the web reel () and the second supporting drum () is maintained, and the first supporting drum () is moved vertically downwards as the diameter of the web reel () grows and moved to such an extent that the measured nip force in the winding nip () remains substantially at a set value or within the range of a predetermined upper and a predetermined lower value.

Method and a machine for winding a web onto spools to form a succession of web reels

The present invention relates to a w winder () for winding a web roll () from a fibrous web such as a paper web or a web of non-woven material paper (). The winder () comprises two support rolls () for supporting the web roll () during reeling and a core shaft () for winding the paper reel (). At each longitudinal end of the core shaft (), there is a carrier chuck () in which the core shaft () is rotatably journalled. The carrier chucks to are arranged to be movable in a frame towards or away from the support rolls () and a rider roll () is arranged to be capable of acting against the web roll () being wound. The rider roll () is carried by a rider roll beam () and the rider roll beam () is arranged to be movable in the frame () such that the rider roll () can be moved towards or away from the support rolls (). There is at least one actuator () for moving the rider roll beam () towards or away from the support rolls (); and at least one load cell () arranged to detect the force between the rider roll () and the web roll (). The winder () also comprises at least one actuator () for moving the carrier chucks () of the core shaft () independently of the rider roll beam () and the winder () comprises at least one load cell () arranged to detect the force with which the carrier chucks () act on the core shaft (). The winder () also comprises a logic control system () connected to the load cells () such that the logic control system () receives measured values for the force between the web roll () and the rider roll () and the force with which the carrier chucks () act on the core shaft (). The logic control system () is programmed to control movement of the carrier chucks () and the rider roll beam () such that the sum of the forces detected from the load cells () and the force resulting from a calculated weight of the web roll () corresponds to a set value for the force between the web roll () and the support rolls (). The invention also relates to a corresponding method for operating the winder.

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Lucca, Italy

Fabrizio Bartolini