Patent ID: 6776877
Filing Date: 2004-08-17
Classification: D21F

Abstract:
A twin wire former for the production of a fiber web from a fiber suspension, said twin wire former comprising:a continuous bottom wire and a continuous top wire, each with a direction of wire travel S, which together define a twin wire zone therebetween; a headbox including a headbox nozzle; a rotating forming roll having an open volume, no suction, a forming roll diameter smaller than 1,400 mm and a forming roll angle of wrap smaller than 7Â°; a forming suction box located immediately following said rotating forming roll, with respect to said direction of travel S; a plurality of forming strips located opposite said forming suction box; an initial area of said twin wire zone in which said bottom wire and said top wire run over said rotating forming roll, said initial area including a wedge-shaped inlet nip defined by the area wherein said bottom wire, said top wire and said rotating forming roll are initially proximate with the fiber suspension, said wedge-shaped inlet nip receiving the fiber suspension from said headbox nozzle at a stock consistency of between 0.4% and 2.0% thereby providing an initial dewatering volume less than 30% on said rotating forming roll; a central area of said twin wire zone in which the fiber web is formed between said bottom wire and said top wire, said central area including a plurality of dewatering elements and a plurality of forming elements, said plurality of dewatering elements including said forming suction box, and said plurality of forming elements including said forming strips; an end zone of said twin wire zone in which said bottom wire and said top wire run over a separating element thereby separating one of said bottom wire and said top wire from the fiber web and from the other one of said bottom wire and said top wire.