AN EXTENDED NIP ROLL, AN EXTENDED NIP PRESS MAKING USE OF THE EXTENDED NIP ROLL, A PAPERMAKING MACHINE AND A METHOD OF OPERATING AN EXTENDED NIP PRESS

摘要

The invention relates to an extended nip roll (5) capable of forming a press nip (N) with a counter roll (7) which press nip (N) has an extension in a machine direction when the extended nip roll (5) cooperates with the counter roll (7). The extended nip roll (5) comprises a flexible jacket; an elastic press body (13) arranged inside the flexible jacket. The top side (14) of the press body (13) is beveled in such a way that, in the machine direction, a working surface (15) of the top side has a downstream end (16) which, in the machine direction, is followed by an exit side surface (17) that diverges from the interior surface (11) of the flexible jacket (10). The press body (13) further has at least a first and a second internal pressure chamber (18, 19). The pressure chambers (18, 19) can be pressurized such that the press body (13) expands. The first internal pressure (18) chamber has an extension in the machine direction that does not extend beyond the working surface (15) and the second internal pressure chamber (19) is located downstream of the first internal pressure chamber (18) and has an extension in the machine direction beyond the downstream end (16) of the working surface (15). The working surface (15) and the exit side surface (17) are made of a material that has a higher shore A hardness than the material in the rest of the press body (13). The invention also relates to an extended nip press and a paper machine in which the extended nip roll is used. The invention further relates to a method of operating the extended nip press.