Metso Paper Inc.

Valmet Paper Machinery Inc.

Valmet Corporation

Juha Ehrola

Kari Holopainen

Pekka Kivioja

Juha Lahtinen

Pekka Koivukunnas

Mika Viljanmaa

Pekka Linnonmaa

Tapio Mäenpää

Erkki Leinonen

Vesa Nokelainen

Silvo Mikkonen

Ilkka Hiirsalmi

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.

Method and arrangement for computing and regulating the distribution of a linear load in a multi-nip calender and a multi-nip calender

A paper machine suction roll has a perforated shell () and a static suction box () sealed against the inner surface of the shell () to create a suction zone () on the roll surface as it rotates. Holes () extending through the shell () are placed at distances (b) of varying magnitude from one another such that the hole pattern formed on the inner surface of the shell () is irregular. Each hole () has a surrounding countersink situated at regular intervals (a) from one another forming a regular countersink pattern on the outer surface of the shell (). 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.

Suction roll of a paper machine

The invention relates to an arrangement for displacing a roll, which is hydrostatically journalled by its axle ( ) 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 ( ) pressurizable with a hydraulic medium and at least one support element ( ). The arrangement of the invention comprises a valve control piston ( ), delivering a hydraulic medium required for the pressurization of said at least one loading element ( ) and positioned in a valve cylinder ( ), said control piston ( ) being provided with a positioning valve ( ) on the face of the control piston ( ) pointing towards the loading element ( ), the face of the control piston ( ) opposite relative to the positioning valve ( ) being coupled with a pressure line (LP) of the hydraulic system for focusing a holding pressure on the control piston ( ).

Arrangement for rapid movement of a roll with hydrostatic bearings

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 ( ) of at least one roll ( ) in the nip roll construction is changed, in which connect the natural frequency of the roll ( ) is also changed. The device that carries out the method comprises a pressure medium accumulator ( ), which has been connected to the pressure side of a loading element ( ) of at least one hydrostatic bearing element ( ).

Method and device for changing the natural frequency of a nip roll construction in a paper or board machine

Bearing control system for a roll with hydrostatic bearings

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.

Variable-crown roll loaded by means of shoes

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.

Reeling drum

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.

Method and apparatus for reel-up of a paper web

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.

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Vaajakoski, Finland

Juha Ehrola