Extended nip press

The method of removing liquid from a traveling fibrous web by applying pressing forces to the web comprising the steps:

• passing a relatively wet web on a carrier felt through a first press nip formed between a pair of rolls;
• immediately passing the web following the first nip through a second, elongate extended nip;
• immediately after the second nip passing the web around a roller and through a third, elongate extended nip spaced from said second nip;
• and
• simultaneously applying opposed pressures in said second and third nips from a force between the nips to different portions of said web respectively received in said second and third elongate nips with the pressure remaining substantially constant throughout each nip and releasing the pressure at the end of said nips,
• whereby the force is such that any reaction forces are opposed.

A press mechanism for removing liquid from a traveling fibrous web comprising in combination:

• a looped endless press belt;
• first and second guide rolls in the ends of the press belt;
• first and second press rolls positioned between the guide rolls and pressing into said belt to form first and second nips;
• a first press felt for carrying a web through the first nip between the belt and felt with the web following the belt on the offrunning side of the first nip and passing through the second nip on the belt;
• a second felt passing through the second nip with the web between the belt and second roll;
• opposed first and second backing shoes in sliding relation with the inner surface of said belt along the extent of said first and second nips with said shoes having an inner surface essentially conforming to the curvature of the press rolls;
• opposed pistons between said shoes, pivotal connections between said pistons and each of said shoes respectively;
• a fluid pressure chamber slidably receiving said pistons with means for directing a fluid under pressure between the pistons so that the forces applied to the pistons are equal and opposite;
• lubricating fluid dams at each side of the nips retaining the lubricating fluid within the area of said shoes;
• means for delivering lubricating fluid to relieved noses on each of the shoes;
• and means for removing excess lubricating fluid from between said dams.

A press mechanism for removing liquid from a traveling fibrous web comprising in combination:

• a first felt receiving a web from a forming section of a paper making machine;
• a second felt guided against the web so that the web is sandwiched between the two felts;
• a first elongate press nip receiving said first and second felts and formed between a press roll and a traveling belt wrapped over the press roll;
• a first shoe urging the belt toward the roll to form an extended nip;
• guide means separating the first felt from the second felt;
• a second nip receiving the second felt with the web thereon and formed between a second press roll and the belt;
• a second shoe within the belt urging the belt toward the second roll forming an extended pressure nip therebetween;
• first and second fluid backing members acting respectively on said first and second shoes and positioned between the shoes so that their reactive forces are in opposition;
• and means for guiding the web rom the offrunning side of the second extended nip.