Thumbnail Image

Disturbances during reel change in paper machines

Eriksson, L.
Paper machines operate continuously. When a machine reel is full, the paper web is transferred to an empty spool. The disturbances in the web which occur during the reel change period are wound-in and later released when the machine reel is unwound, causing disturbances in the winder and in the quality of the shipping rolls.
A measurement system was built to capture and to characterize the disturbances in web tensions and rotation speeds during the reel change period. To measure the rotation speed of the machine reel during the whole change sequence at different positions along the periphery of the pope drum a transducer with infrared transmitting of data from the machine reel to the measurement system was developed.
Large disturbances occurred due to acceleration and deceleration of the angular winding velocity of the machine reel when it moved along the periphery of the pope cylinder from the starting position to the normal winding position. The interaction between the pope and the calender section introduced rapid disturbances of the web tension. The deviation between results of measurement and simulation of an ideal winding was used to characterize the disturbances. The method can be used to study results of different ways to improve the winding. This has been demonstrated.