Unwinding section and a method of joining ends of fiber webs in an unwinding section

Abstract

The invention relates to a method and an unwinding section for unwinding a fiber web from a parent roll, which unwinding section comprises at least one unwinder for unwinding a fiber web from a parent roll and a joining device configured to join a trailing end of a running-out parent roll to a beginning end of a next, new parent roll to be unwound in a parent roll change. The unwinding section comprises a broke handling device configured to handle broke. The unwinding section comprises a tensioning device located between the joining and the broke handling, and the tensioning device is configured to tension and straighten the fiber web to be joined between the tensioning device and the joining device before joining of the end of the fiber web from the running-out parent roll and the end of the fiber web from the next parent roll to be unwound.

1 . Unwinding section for unwinding a fiber web from a parent roll, which unwinding section comprises at least one unwinder for unwinding a fiber web from a parent roll and a joining device configured to join a trailing end of a running-out parent roll to a beginning end of a next, new parent roll to be unwound in a parent roll change, and which unwinding section comprising a broke handling device configured to handle broke, which unwinding section further comprises a tensioning device configured to tension and straighten the fiber web to be joined between the tensioning device and the joining device before joining of the end of the fiber web from the running-out parent roll and the end of the fiber web from the next parent roll to be unwound, the tensioning device being located between the joining and the broke handling the tensioning device being configured to guide the cut beginning end of the fiber web from the next parent roll to be unwound after the joining of the ends of the fiber webs in the parent roll change to the broke handling device. 
     
     
         2 . Unwinding section according to  claim 1 , the unwinding section being located on a maintenance level and comprising an opening for removal of broke fiber web to the broke handling device and that the tensioning device is located above the opening and downstream in running direction of the fiber web running from the next parent roll to be unwound from the joining device. 
     
     
         3 . Unwinding section according to  claim 1 , the tensioning device being configured to guide the beginning end of the fiber web from the next parent roll to be unwound towards the opening and the broke handling device. 
     
     
         4 . Unwinding section according to  claim 1 , the unwinding section comprising a counter roll for the tensioning device, and the counter roll being configured to provide a tensioning effect with the tensioning device and the fiber web from the next parent roll to be unwound being configured to be guided between the counter roll and the tensioning device. 
     
     
         5 . Unwinding section according  claim 1 , the tensioning device being movable between a resting position and a tensioning position. 
     
     
         6 . Unwinding section according to  claim 1 , the tensioning device comprising a continuous belt loop running and supported by at least two rolls located inside the belt loop. 
     
     
         7 . Unwinding section according to  claim 1 , the unwinding section comprising two unwinders and the joining device comprising a movable tool element and a stationary counter element. 
     
     
         8 . Unwinding section according to  claim 1 , the unwinding section comprising only one unwinder and the joining device comprising a stationary tool element and a movable counter element. 
     
     
         9 . Unwinding section according to  claim 1 , the unwinding section being an unwinding section of a slitter-winder. 
     
     
         10 . Method for joining ends of fiber webs in a parent roll change of an unwinding section located in vicinity of or comprising a broke handling device configured to handle broke, in which method the ends of the fiber webs are configured to be joined by a joining device, in which method the fiber web running from a next parent roll to be unwound is tensioned and straightened by a tensioning device before joining of the end of the fiber web from the running-out parent roll and the end of the fiber web from the next parent roll to be unwound, the tensioning device being located between the joining and the broke handling, the cut beginning end of the fiber web from the next parent roll to be unwound after the joining of the ends of the fiber webs in the parent roll change being guided to the broke handling device. 
     
     
         11 . Method according to  claim 10 , the fiber web running from the next parent roll to be unwound being tensioned and straightened by the tensioning device above a maintenance level. 
     
     
         12 . Method according to  claim 10 , the fiber web running from a next parent roll to be unwound being further tensioned and straightened by a tensioning device simultaneously and after joining of the end of the fiber web from the running-out parent roll and the end of the fiber web from the next parent roll to be unwound. 
     
     
         13 . Method according to  claim 10 , the ends of the fiber webs being configured to be joined by a joining device comprising a tool element and a counter element, and the trailing end of the fiber web from the running-out parent roll and the beginning end of a new fiber web from the next parent roll being guided to an overlapping position between the tool element and the counter element for joining, and the beginning end of the fiber web running from the next parent roll to be unwound being tensioned between the joining device and the tensioning device. 
     
     
         14 . Method according to  claim 10 , the unwinding section being run at a crawling speed during the joining of the ends of the fiber webs.