Dimensioning of rolls in wide nip roll press

摘要

A roll press including at least two rolls forming a press nip for the treatment of a web of material. A press roll includes a very flexible roll shell which is rotatable around a stationary support. The roll shell is mounted by at least one support element on the support. The support element has a concave support surface which forms a wide press nip with the backing roll. This provides a roll press which, even in the case of a backing roll which is without sag control, defines a press nip which is very substantially uniform. This is achieved by having the outer circumference of the shell of the press roll change in dimension in the axial direction from the axial center of the roll towards the ends of the roll, i.e., the outer circumference may increase or decrease. The circumference of the backing roll may or may not correspondingly change in the axial direction.