Patent ID: 6267846
Filing Date: 2001-07-31
Classification: D21F

Abstract:
A twin wire former for manufacturing a fibrous material web from a fibrous suspension, the twin wire former comprising:a movable top wire belt arranged to move in a travel direction from a top roll to a bottom roll, wherein the top roll is arranged adjacent a headbox and the bottom roll comprises one of a deflection roll and a suction roll;a first imaginary straight path being defined between the top roll and the bottom roll;a rotating forming roller arranged adjacent the headbox;a second imaginary straight path being defined between the forming roller and the bottom roll;a movable bottom wire belt arranged to move in the travel direction with the movable top wire belt from the rotating forming roller to the bottom roll;the movable top wire belt and the movable bottom wire belt converging at a twin wire zone, the twin wire zone having a first section adjacent the headbox, a second section disposed after the first section in the travel direction and an end section which follows the second section in the travel direction;the movable top wire and the movable bottom wire forming a wedge-shaped inlet gap at said first section of said twin wire zone, wherein the inlet gap is adapted to receive the fibrous suspension from the headbox;the second section being arranged in a steep downward direction downstream of the forming roller in the travel direction;the forming roller deflecting the movable top wire belt and the movable bottom wire belt from the first imaginary straight path and away from the headbox;at least one drainage element arranged in the second section, the at least one drainage element comprising one of first and second opposite facing balanced-pressure drainage elements and a deflection device which deflects the movable top wire and the movable bottom wire from the second imaginary straight path and towards the headbox,wherein the bottom wire belt and the top belt are adapted to form the fibrous web therebetween at the second section of the twin wire zone.