ATE262074T1 - PRESS SECTION IN A PAPER MACHINE WITH ONE OR MORE LONG NIP PRESSES - Google Patents

Abstract

A press section in a paper machine, which press section comprises at least two separate press nips (NP1, NP2; N1, N2, N10, N20, N30, NP10, NP11, NP20, NP21, NP30). The paper web (W) is passed through these nips as a closed draw. In the press section there is at least one press nip provided with two press felts (31, 41; 32, 42) that receive water, through which press nip the paper web (W) runs between said press felts (31, 41; 32, 42). After the last-mentioned nip the paper web (W) is separated from one of the press felts (31/41; 32/42) and transferred on support of the other press felt (41/31; 42/32) as a closed draw further. The last nip is an extended-nip zone (NP2; NP10; NP20, NP21, NP30), in which one roll is a shoe roll (12) provided with a hose mantle (14) and with a press shoe arrangement (13), and the other roll is a press suction roll (22) provided with a suction zone (23). The paper web (W) is passed through the last extended-nip zone (NP2; NP10; NP20, NP21, NP30) between two press fabrics (32, 42). Directly after the last extended-nip zone (NP2; NP10; NP20, NP21, NP30) the paper web (W) is separated from one of the press fabrics (32/42) and transferred, with the aid of the vacuum present in the suction zone (23) of the press suction roll (22), to follow the press fabric (42/32) placed at the side of the press suction roll (22) without rewetting. The web (W) is passed on the latter press fabric (32; 42) as a closed draw onto a drying wire (51) of the dryer section. Further, a modification of the press section is described in which an extended-nip zone which corresponds to the extended-nip zone mentioned above and placed as the last nip is placed as the first nip in the press section.