FOERFARANDE OCH ANORDNING I CYLINDERTORKEN AV EN PAPPERSMASKIN, VID VILKEN ETT DRAG MED DUBBEL VAEVNAD ANVAENDS

摘要

PURPOSE: To increase the level of a negative pressure and improve the tension of a web at a region where the web is released from a drying cylinder, by disposing an air-jetting means having a special structure in the paper web- releasing region. CONSTITUTION: An air-jetting device 10 is disposed in a region where a made web (wet paper) WP is released together with a metal net 40 from a drying cylinder 41, in order to press the web WP to the drying cylinder 41 by the use of the wire cloth 40 and then transfer the web WP to another drying cylinder 32. A negative pressure is thus formed in the releasing region to improve the release of the web. The air-jetting device 10 is formed in such a structure that negative pressure regions A-, N- are flat L in the jetting direction, that a passage R formed between the outer surface of the wire cloth 40 disposed on the cylinder 41 and the wall surface 14 of the air-jetting device 10 is enough long, and that the flow of a boundary layer following the metal net is returned in the direction opposite to the travel direction of the wire cloth 40 to originally form a proper level of negative pressure in a space formed on the rear side of the passage R.