Patent ID: 6413369
Filing Date: 2002-07-02
Classification: D21F

Abstract:
An apparatus for forming a multilayered paper or paperboard web from stock suspensions containing papermaking fibers and fines, the apparatus comprising:a first forming unit including a forming roll, an inner wire, and an outer wire, the first forming unit being operable to produce a fiber web having a higher concentration of fines at one side than at an opposite side of the web; a second forming unit including a forming roll, an inner wire, and an outer wire, the second forming unit being operable to produce a fiber web having a higher concentration of fines at one side than at an opposite side of the web; and a couch device for couching together the webs from the first and second forming units, wherein the forming units and couch device are arranged relative to one another so as to place the sides of the webs having the higher concentration of fines in contact with each other for couching together to form the multilayered web; and wherein each of the forming units is arranged such that the inner and outer wires pass along a portion of the circumference of the forming roll to form an initial curved section of a forming zone in which initial dewatering takes place so as to form a web having an inner wire side against the inner wire and an outer wire side against the outer wire, wherein said curved section is followed by a section having additional drainage members operable to further dewater the web, and wherein the forming roll is an open forming roll operable to produce a higher concentration of fines at the inner wire side of the web than at the outer wire side.