Abstract: A method and arrangement for computing and regulating distribution of linear load in a multi-nip calender. A material web is passed through the nips in a set of rolls including a variable-crown upper roll, a variable-crown lower roll and intermediate rolls positioned between the upper and lower rolls. The rolls in the set of rolls are supported so that, when the nips are closed, the bending lines of the rolls are curved downwards. When computing and regulating the linear loads, one or more of the physical properties affecting the bending of each intermediate roll under load, such as bending rigidity, mass, shape, and material properties, are taken into account. The ratio of the linear loads applied to the intermediate rolls, the weight of the rolls per se, and/or the support forces applied to the rolls are regulated so that the set of rolls is in a state of equilibrium and a predetermined state of deflection.

Abstract: A paper machine suction roll has a perforated shell (10) and a static suction box (11) sealed against the inner surface of the shell (10) to create a suction zone (11a) on the roll surface as it rotates. Holes (14) extending through the shell (10) are placed at distances (b1) of varying magnitude from one another such that the hole pattern formed on the inner surface of the shell (10) is irregular. Each hole (14) has a surrounding countersink situated at regular intervals (a) from one another forming a regular countersink pattern on the outer surface of the shell (10). A conventionally drilled suction roll produces very powerful noise peaks at certain multiples of rotation frequency. When the position of the holes is changed at random in particular in the circumferential direction, regular periodicity disappears and the sound produced is a less disturbing humming-type sound.

Abstract: The invention relates to an arrangement for displacing a roll, which is hydrostatically journalled by its axle (1) on support structures and positionable in its working position by means of a bearing, through a rapid movement of the bearing out of its said working position. The journalling comprises at each end of the roll at least one loading element (2-4) pressurizable with a hydraulic medium and at least one support element (5). The arrangement of the invention comprises a valve control piston (9), delivering a hydraulic medium required for the pressurization of said at least one loading element (2) and positioned in a valve cylinder (8), said control piston (9) being provided with a positioning valve (10) on the face of the control piston (9) pointing towards the loading element (2), the face of the control piston (9) opposite relative to the positioning valve (10) being coupled with a pressure line (LP) of the hydraulic system for focusing a holding pressure on the control piston (9).

Abstract: A paper machine suction roll has a perforated shell (10) and a static suction box (11) sealed against the inner surface of the shell (10) to create a suction zone (11a) on the roll surface as it rotates. Holes (14) extending through the shell (10) are placed at distances (bi) of varying magnitude from one another such that the hole pattern formed on the inner surface of the shell (10) is irregular. Each hole (14) has a surrounding countersink situated at regular intervals (a) from one another forming a regular countersink pattern on the outer surface of the shell (10). A conventionally drilled suction roll produces very powerful noise peaks at certain multiples of rotation frequency. When the position of the holes is changed at random in particular in the circumferential direction, regular periodicity disappears and the sound produced is a less disturbing humming-type sound.

Abstract: A method for changing the natural frequency of a nip roll construction in a paper or board machine. In the method, the bearing elasticity of a hydrostatic bearing element (10, 20, 30, 40) of at least one roll (1) in the nip roll construction is changed, in which connect the natural frequency of the roll (1) is also changed. The device that carries out the method comprises a pressure medium accumulator (39), which has been connected to the pressure side of a loading element (13, 23, 33) of at least one hydrostatic bearing element (10, 20, 30).

Abstract: A bearing control system for a roll with hydrostatic bearings which is mounted by its axle on a bearing block or other equivalent frame member by hydraulically loaded hydrostatic bearing elements. A principal bearing element acts in a principal loading direction and another bearing element is a backup bearing element which acts in a direction opposite to the principal loading direction. The bearing elements include bearing shoes positioned freely around the axle in order to support the axle so that the roll revolves freely in relation to the bearing block or other frame member. The control system feeds a hydraulic pressure medium to the hydrostatic bearing elements so that the roll is displaceable in the principal loading direction, e.g., in the direction of the nip plane, by displacing the axle via the bearing elements.

Abstract: A variable-crown roll including a stationary roll axle, a tubular roll mantle rotatably mounted by its ends on the roll axle by end bearings and hydraulic loading shoes arranged between the roll mantle and the roll axle. The loading shoes act upon an inner face of the roll mantle in a direction toward a nip defined in part by the roll, are supported on the roll axle and are loaded by a hydraulic pressure medium. The nip pressure is profiled in the axial direction of the roll by regulating the pressure of the pressure medium passed into the loading shoes. The roll mantle is made of a fiber-reinforced composite material so that the stability of shape of the roll mantle in the direction of the circumference is good, i.e., it maintains its shape, and the rigidity in the axial direction is low, i.e., it is profitable.

Abstract: The invention concerns a reeling drum for a paper or board machine or equivalent, onto which reeling drum a material web, in particular paper or board, is reeled. Axle journals have been fixed to the ends of the reeling drum in a conventional way by means of end joints. By means of the axle journals, the reeling drum is supported in a revolving manner on a machine frame by means of bearing means. According to the invention, the reeling drum is provided with articulation devices or the like for variation of the deflection of the reeling drum and for equalization of the pressure produced by the material web reeled ont the reeling drum. The reeling drum has an inner mantle supported on the machine frame revolvingly, and an outer mantle fitted on the inner mantle coaxially. A gap remains between the inner mantle and the outer mantle, the outer mantle being supported on the inner mantle by means of the articulation devices.

Abstract: A method and apparatus for reel-up of a paper web, wherein a roll is formed around a reeling drum or in another embodiment of the invention on the support of carrier rolls or carrier belts, and wherein a reeling cylinder is used to form a reeling nip for contacting the roll which is to be produced during passage of the paper web through the reel-up apparatus, includes a center axle and a cylinder mantle mounted for revolution around the axle comprised by the reeling cylinder. A method and apparatus for reel-up of a paper-web includes hydraulic loading elements for adjusting deflection of the cylinder mantle such that distribution of line pressure in the reeling nip, in its axial direction is controlled, e.g. maintained to be substantially uniform.

Abstract: A method and apparatus for reel-up of a paper web, wherein a roll is formed around a reeling drum or in another embodiment of the invention on the support of carrier rolls or carrier belts, and wherein a reeling cylinder is used to form a reeling nip for contacting the roll which is to be produced during passage of the paper web through the reel-up apparatus, includes a center axis and a cylinder mantle mounted for revolution around the axle comprised by the reeling cylinder. A method and apparatus for reel-up of a paper-web includes hydraulic loading elements for adjusting deflection of the cylinder mantle such that distribution of line pressure in the reeling nip, in its axial direction is controlled, e.g. maintained to be substantially uniform.

Abstract: Method for stabilizing a glide shoe loaded against an inner face of a revolving mantle of a roll adjustable in zones. The glide shoe is supported by an articulated joint on a piston which loads the glide shoe with adjustable pressure. In order to ensure lubrication of the glide face between the glide shoe and the inner face of the roll mantle, within an area of a front edge of the glide face as seen in a direction of rotation of the roll mantle, a shifting and/or steepening of compression pressure applied by the glide shoe through lubricant onto the inner face of the roll mantle is produced by means of a wedge space within the front edge of the glide face, said shifting and/or steepening in turn generating a moment having a direction opposite to a direction of a moment produced by frictional force of the glide face of the shoe. The thickness of the lubricant film is increased by this moment in the area of the front side of the glide face.