Förbättrad körbarhet av en bana i en materialsbanamaskin

摘要

A runnability device, for example a runnability box such as a suction box, is for achieving improved runnability of a web when the web (W) progresses supported by a wire ( 61 ) to a closing gap between a roll and the wire. The runnability device ( 10 ) is located on the side of the wire before the roll and extends over the width of the web so that there is a slot between the wire and the runnability device. The runnability device comprises devices ( 11 ) for directing a vacuum from the side of the wire over the width of the closing gap so that the vacuum in the edge area (E) of the web wire is greater than in the central area of the web wire. A characteristic feature of the invention is that the vacuum device ( 11 ) which creates the vacuum effect is adjustable in the cross-direction of the web wire.