Calender for a material web, and a method for calendaring the material web. The calender includes a frame upon which at least one roll stack is mounted. The roll stack includes a plurality of rolls, in which the end rolls are designed as sag compensation rolls. An intermediate roll adjacent to one sag compensation roll is fixedly mounted to the frame. An adjusting device adjusts the sag compensation roll to control a compressive stress in a first nip, in such a manner that the compressive stress in the first nip is adjusted independently of a compressive stress in a following nip.
A multi-roll calender (1) has one or several sets of rolls (2) attached to a frame (7) so that each set of rolls has at least three rolls. At least the first roll (3; 31) and the last roll (3; 32) have casings which can be moved toward the intermediate rolls (4). The first roll (3; 31) and the last roll (3; 32) are fixedly attached, at least one of the intermediate rolls (4) in the set of rolls is fixedly attached, and the other intermediate rolls are provided with lightening elements for lightening the auxiliary means related to the intermediate rolls. The roll nips (N) in the set of rolls (2) are closed by moving the first roll towards the intermediate rolls (4), and the roll nips between the last roll and the fixed intermediate roll included, are closed by moving the last roll towards the intermediate rolls (4).
Calender with a roll stack and process for arranging rolls in a roll stack of a calender, the calender comprising two end rolls in a press plane and a plurality of middle rolls between the two end rolls. At least one of the middle rolls has an elastic surface and has a displacement (x) relative to the press plane, the size of the displacement (x) being selected based on a wavelength of a critical natural frequency within the roll stack. The end rolls and the at least one middle roll define two nips therebetween, the displacement (x) effecting a difference in distance of a fraction of a wavelength on a surface of the at least one middle roll between the two nips. An adjusting device adjusts the displacement of the at least one middle roll on the basis of a preset displacement (x), which depends on the wavelength.
Calender including a roll stack having a plurality of rolls that rest against one another in a press direction. At least one of the rolls has an elastic surface. A vibration recording device determines in an uninterrupted manner a vibration of at least one of the rolls. A mechanism displaces the at least one roll crosswise to the press direction based on the vibration. The process includes determining in an uninterrupted manner a vibration of at least one of the rolls and displacing the at least one roll crosswise to the press direction based on the vibration.
Process for operating a calender having a roll stack formed by a plurality of rolls resting against one another in a press direction along a stack plane, at least one of the rolls including an elastic surface. The process includes determining whether a barring pattern has occurred on at least one of the rolls, determining a wavelength of the barring pattern, and displacing at least one of the rolls based upon the wavelength.
A multi-roll calender, supercalender, soft calender or equivalent has at least one nip (YN, PN1, KN, PN2, AN) profiling a fibrous web (W) which is being calendered. A shoe roll (1, 4, 6, 10) constitutes at least one of the calender rolls which define the nip. A shell (11, 41, 61, 101) of the shoe roll is of a composite material, and the shoe roll is provided with internal shell-loading shoes (12, 42, 43, 62, 63, 103) for profiling the shell, the nip and/or the fibrous web.
