Valmet Corporation

Metso Paper Inc.

Valmet Paper Machinery Inc.

Pekka Kivioja

Juha Lahtinen

Kari Holopainen

Juha Ehrola

Esa Lensu

Esa Salavamaki

Juhani Niskanen

Jorma Snellman

Ari Lehto

Vesa Nokelainen

Aki Mikkola

Pekka Koivukunnas

Mika Viljanmaa

Pekka Linnonmaa

Reima Kerttula

Jori Onnela

Ari Linsuri

Juha Isomets&auml;

Tapio Mäenpää

Erkki Leinonen

Timo Nyberg

Tuomo Kurkela

Risto Haiko

Esa Vilmusenaho

Mauri Rukaj&auml;rvi

Ilkka Hiirsalmi

Juha Laitinen

Esa Salvamaki

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

The invention relates to a method for providing a roll ( ) for a paper machine with sliding bearings, the roll comprising a stationary roll axle ( ) and a tubular roll mantle ( ) arranged to revolve around it. In the method, the roll mantle ( ) is supported on the roll axle ( ) by means of hydraulic sliding bearing members ( ) which are arranged to accomplish radial fitting with bearings of the roll mantle in the loading direction and in the lateral direction with respect to it, and the axial fitting with bearings of the roll mantle. The sliding bearing members are loaded by means of a hydraulic medium, the feed of which to the sliding bearing members is controlled by means of control valves ( ). In the method relating to the invention, when loading (F) is applied to the sliding bearing member ( ) effective in the loading direction, the loading force applied to the sliding bearing member ( ) subject to an external load due to the loading is compensated for automatically, essentially immediately, without an external control instruction, by means of the movement of the control valve ( ) stem ( ) of the sliding bearing member ( ) subject to loading, the said control valve ( ) bringing about a rapid increase in the pressure of the hydraulic medium in the sliding bearing member ( ) subject to the external load, at the same time as the pressure of the medium supplied to the sliding bearing member ( ) located radially on the opposite side of the roll axle ( ) in the loading direction is adjusted to a certain minimum value, whereby the bearings of the roll mantle are rendered so as to be essentially without stroke. The invention also relates to a roll for a paper machine which is provided with sliding bearings.

Method for providing a roll for a paper machine with sliding bearings and a roll for a paper machine with sliding bearings

The invention relates to a slide shoe assembly for a roll ( ) in a paper/board machine or a finishing machine, said roll ( ) comprising a stationary axle ( ), around which is rotatably mounted a cylindrical roll shell ( ), a clearance ( ) formed between the axle ( ) and an inner surface ( ) oF the roll shell ( ) being fitted with loading elements ( ) operated by a pressurized hydraulic fluid and provided with slide shoes ( ) which are loadable against the inner surface ( ) of the roll shell ( ) for controlling the distribution of a nip pressure in a nip (N) established with a counter roll ( ). According to the invention, the loading element is equipped with means capable of eliminating or compensating for a nip-load induced deflection of the roll shell and/or a deflection of the slide shoe caused by the pressure of a hydraulic medium, thereby eliminating the harmful effects caused by said deflections on an oil film between the loading shoe and a cylindrical surface supported thereby.

Slide shoe assembly for a roll in a paper/board machine of a finishing 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 roll that can be bent for a web-like material, which roll comprises a continuous tubular roll mantle ( ) of composite material as well as axle journals ( ) connected to each end of the roll mantle ( ). The axle journals ( ) are attached by means of at least one mechanism ( ), by whose means the axle journals ( ) and thereby the roll mantle ( ) are bent into an arc form, and a regulation device ( ) by whose means the angular position of the roll arc can be regulated.

Roll that can be bent for a web-like material

A tubular roll with glide bearings and a method for providing a tubular roll mantle with glide bearings. The roll mantle is supported on a roll axle by hydraulic glide bearing elements which are loaded hydraulically by a pressure medium. The roll is loaded from outside radially in a principal loading direction and the roll mantle is supported on the roll axle by glide bearing elements in the principal loading direction. The loading pressure and lubricant are fed to the glide bearing elements as separated from one another so that the movement of the roll mantle, the speed of movement and the change in speed are regulated by opening, closing and/or throttling the flow in the pressure duct of the loading pressure. The lubricant may be fed to the glide bearing elements irrespective of the loading pressure.

Tubular roll provided with hydraulically loaded glide bearings

A closing valve for a regulation valve of a roll in a paper machine, such as a variable-crown roll, including a frame part arranged between the regulation valve of a regulation valve block and a block frame and in which pressure medium ducts are formed. The closing valve includes a connecting part movable in relation to the frame part and having closing members mounted thereon and which are arranged to extend into the pressure medium ducts in the frame part. When the connecting part is displaced in relation to the frame part, the closing members attached to the connecting part close and open the pressure medium ducts in the frame part. A variable-crown roll including one or more closing valves is also disclosed.

Closing valve for a regulation valve of a variable-crown roll in a paper

Hydrostatic glide bearing for a roll or equivalent

Method and arrangement for automatic monitoring and correction of the regulation pressure of regulation valves in a regulation valve block in a variable-crown roll in a paper machine. The regulation pressure of the regulation valve in each regulation zone in the regulation valve block can be connected alternatingly to a reference pressure detector whose measurement signal is compared with the measurement signal of the actual value of the regulation pressure in the regulation zone concerned. The result of the comparison is stored on the page of monitoring of pressure detectors contained in the central computer system, on which page, in addition to this difference, set values and actual values of the regulation zone pressures as well as the value of the reference measurement are provided. In addition, a correction can be made to the actual value of the regulation pressure in the regulation zone concerned if the difference between the measurement signal of the reference pressure detector and the measurement signal of the actual value of the regulation pressure in the regulation zone concerned is higher than a predetermined value.

Method and arrangement for automatic monitoring and correction of the

Bearing control system for a roll with hydrostatic bearings

A method for calendering a paper web, including the steps of passing the paper web through a calendering nip having a profile formed from a pair of calendering rolls, wherein at least one of the pair of calendering rolls includes a soft exterior face at least in the region of the nip, regulating the profile of the calendering nip to compensate for flaws in the paper web passing through the calendering nip including varying the properties of the soft exterior face locally in a direction transverse to the direction of the passing paper web concurrently with the passing step.

Method for calendering a paper web and a calendar that makes use of the

A method for fitting a roll mantle of a tubular roll used in a paper machine or equivalent with glide bearings and a tubular roll. The roll mantle is supported on a stationary roll axle by hydraulic glide bearing elements acting upon the roll mantle and/or upon the roll ends. The bearing elements are loaded hydraulically by the pressure of a first pressure medium. The roll is loaded from outside radially in the direction of at least one plane, i.e. in a so-called principal loading direction. The roll mantle is supported on the roll axle by the glide bearing elements which act radially substantially in the principal loading direction in opposite directions and which are provided with a device for regulating the braking pressure provided by a second pressure medium, so that in the principal loading direction, the roll mantle is allowed to move over a certain distance. When the roll mantle approaches its preset extreme position in that direction, the movement of the roll mantle is braked and slowed down by the regulation device, and finally the movement is stopped in its extreme position by the glide bearing elements.

Method for providing a roll mantle of a tubular roll for a paper machine

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

A method and apparatus for regulating the temperature in end areas of a roll mantle of a variable-crown roll provided with glide bearings and/or for compensating for an error in the diameter of the roll arising from thermal expansion. The roll mantle of the roll is supported adjustably on the roll axle by hydraulic loading elements loaded by a pressure medium and acting upon the inner face of the roll mantle at least in the direction of the nip plane. Further, the roll mantle is supported on the roll axle by hydraulic glide-bearing elements loaded by a pressure medium and arranged in the areas of the ends of the roll mantle. A fluid is supplied into the end areas of the roll and has a regulated temperature and/or flow so that it is possible to keep the temperature in the end areas of the roll mantle at a desired level, for example, substantially at the same level as the temperature in the middle area of the roll.

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Muurame, Finland

Pekka Kivioja