Web-like material can be manufactured of a mixture containing a solid and a fluid so that a path is formed, in which the fluid is removed from the mixture. In a con- ventional manufacturing process of paper or board, the web is formed from a sus- pension containing fibre and liquid (water). In so-called dry web formation, wet fibres are blown to form a web by means of a gas jet (an air jet).

In paper or board manufacture, it is important that the properties of the paper or board to be manufactured remain desired as accurately as possible both in the ma- chine and the cross direction of the web. Therefore, in the production equipment, there are adjustable mechanical elements in several places. Such elements are pro- vided to adjust, i. e. , to profile the properties in the cross direction in particular.

The properties of paper or board can vary in the cross direction both because of the phenomena in the path itself (e. g. , irregular web formation), and the properties of<BR> the devices in the cross machine direction (e. g. , deflection of roll). At present, thickness profiling is carried out by adjusting the head box and/or the nip pressures of calender. The trend is nowadays to achieve more accurate profiling. The shank pitch of the head box, for example, is at present 75 mm or even smaller. The re- sponse in the calender is considerably wider (e. g. , about 300 mm), which is due to the thickness of the jacket tube in particular (at present about 70 mm). Development is slowly headed towards thinner and thinner wall thickness, but the present tech- nology does not allow jackets with a thickness of only a few millimetres.

Known equipment for adjusting the properties of paper or board, for example, use electromechanical or hydraulic devices, which can be very complex and difficult to control.

Description of the invention A manufacturing equipment for web-like material according to claim 1 has now been invented. Furthermore, a manufacturing method for web-like material accord- ing to another independent claim has been invented. The dependent claims describe some preferred embodiments of the invention.

Adaptive material can be, for example, strictive material, such as magnetostrictive (MS), electrostrictive (ES) or piezoelectric, such as biopolymeric material. Their functioning is based on changes in the form, volume or dimensions, when magnetic or electric fields affecting them change. Adaptive material can also be rheological material, such as magnetorheological (MR) or electrorheological (ER) material, which reacts on changes in magnetic or electric fields by changing its material be- haviour or material properties, such as elastic, viscous, viscoelastic or elastovis- coplastic properties. Adaptive material can also be composite material provided with adaptive properties, wherein an actually adaptive substance is mixed with an- other material, so called host phase, such as a polymer, as part of the composite structure. There can be adaptive material in the composite structure, for example, in the reinforced fibre phase or in the binding agent or filler phases. Examples of com- posite materials include MS/ES composites or polymers, so called ferropolymers (ferrogels) and piezopolymers (such as PVDF).

The solution according to the invention can, for example, comprise a part that is fully or partially manufactured from adaptive material, such as a mechanical part or a machine element.

The solution according to the invention can, first, be used to actively affect the properties or functioning of the parts in question, for example, by changing some properties of the part, such as rigidity, the dimensions or the state of stress in the part. Controlling the rheological properties of certain parts also provides advan- tages. Such parts include parts containing polymer or rubber. According to the in- vention, the viscoelastic properties of these parts can be controlled in particular.

The invention is intended to eliminate deflections, to adjust the rigidity of the struc- ture or to change the dimensions of a section, for example. In this embodiment, we are talking about so-called actuator material. As examples, we could mention de- flection of roll or change in roll diameter. These can be caused, for example, by a varying load or a changing thermal stress. These changes can be compensated for by means of the invention. The solution can also be used to directly control the de- sired objects without compensating for the changes caused by other phenomena.

The operating principle of the invention can also be utilized inversely and passively by observing only the status of the object, for example, by measuring the magnetic or electric field generating in the adaptive (sensitive) material. The object can be a part of a larger structure or a separate sensor designed for observation only. The goal can be, for example, measuring the state of stress, pressure in particular, or forces. This embodiment deals with so-called sensor material.

Providing regulating and return coupling in an active application is easy by measur- ing the current and the voltage supplied. In a passive object, measurement data are obtained from the object by measuring the generated magnetic or electric fields.

One of the objects of the invention can be to control the need for adjustment caused by the wear of a part, such as the slot of a nozzle or the tip of a blade apparatus, to ensure the operation of the device.

A body made of adaptive material can be deformed by means of magnetic or elec- tric fields. In this way, the functioning of the body can be guided in a controlled manner without any actuators being in contact with it. For example, magneto-or electrostrictive material, electroactive polymer or memory metal (such as TiNiNol) can be used. Alloys, the dimensions of which change, when a magnetic field is ex- erted on them, are also commercially available (e. g. , the ferromagnetic material Ter- fenolTM). By means of a dimensional change in adaptive material, the desired force or movement can be provided in a controlled manner. Because of the controlled di- mensional changes, desired forces can also be produced locally. The effect of force can be exerted in a desired direction. Furthermore, the location of the member can <BR> <BR> be implemented according to the invention without a separate, e. g. , electronic return coupling system.

The behaviour of strictive materials in a field is based on changes at a molecular level.

The rheological materials according to the invention are characterized in that a magnetic or an electric field can be used to impact their properties, viscosity in par- ticular. This is based on the fact that these materials have particles, which are ar- rayed under the effect of the field. Generally, the MR/ER substances are formed from a basic phase and polar microparticles that react to the field. The particles are usually fine-grained ferromagnetic material. Examples of such materials include ferropolymers, ferrogels, MS/ES polymers and piezopolymers.

According to the invention, the quality properties of the web-like material to be manufactured, and the runnability or controllability and manageability of the proc- ess can be improved. Furthermore, the production capacity can be increased increas- ing the width of the path in particular.

The objects of application of the invention include the head box, the press section, the drying section, the calender, the coating machine and the reelers, and especially the machine components and elements used in them, such as supporting structures, rolls, doctor knives, steamers, moisteners, measuring beams and measuring systems.

Objects of application also include the coatings, such as the polymer coatings of rolls, belts and wires.

The invention can be used, for example, in trying to eliminate deflections or vibra- tions or to adjust the rigidity of structure. It may be necessary to eliminate espe- cially the natural bend of the structures in the cross direction of the path. Further- more, bending can be caused by thermal expansion or some occasional reasons. The invention also covers the possibility to use deflection measurement or calculated values of bends, when defining the controls that are used to correct the bend defects of the structures and to impact the rigidity of the structures. One application com- prises structures that are kept off the web, such as driers and steamers. In that case, a special advantage is that the structures can be located nearer, because the bends caused, for example, by thermal expansion can be controlled in a better way. One of the objects can also be the need for adjustment that is caused by wear of a part. In this way, the operation of a blade or a nozzle, for example, can be ensured.

According to one embodiment, the body comprises, for example, in the cross direc- tion of the path, several adjacent sections, which have adaptive material. In that case, each section can be influenced separately, when so desired.

The adjustable body can be a body that directly affects the path, or a measuring element, or an actuator or a supporting or fastening organ of such bodies.

The adjustable body can be one that essentially works in the same way throughout the width of the path. Such a body can be a blade, the lip of a gap, a beam or a rotat- ing element.

The adjustable body can also be such a body in the transverse direction of the path, as operates in different ways in different spots. The purpose in that case can be profiling or measurement, for example.

The magnet that provides the effective magnetic field can be, for example, an elec- tromagnet, the strength of which can be altered, or any kind of a magnet, such as a permanent magnet, which can be moved relative to the adjustable element.

One object of the invention is to provide blade fittings. Generally, a blade in this connection refers to various mechanical elements, which in the manufacturing proc- ess are in contact with the pulp flow or the web formed from it, or with the transportation, supporting, and handling equipment of the pulp or the web, such as wires, cylinders or rolls. Typical applications include the fastening structure and the control of the end list of the head box, the blade holder or doctor blade construc- tions of coating stations, and the blades and blade holders of various roll doctors.

Especially calenders can have roll doctors, for example, on chilled, steel or polymer rolls. The purpose of the invention is to provide accurate control and management

purpose of the invention is to provide accurate control and management of the blade in the machine direction or the cross direction. Adaptive material can be provided in the blade itself, or in its fastener or actuator. The invention can be used to exert on the blade a movement or a force of a desired magnitude both in the machine and cross directions to achieve the process targets. The invention can also be used to <BR> <BR> control the blade location accurately without a separate, e. g. , electronic feedback location measurement system. As any deformations caused by thermal expansion, for example, can be controlled better, the blade, such as a doctor blade, can also be located nearer the object. One purpose can also be eliminating problems with vibra- tion. Such an application is especially a blade coating station, where harmful vibra- tion occurs at high velocities in particular. According to the invention, the blade fittings can also be compensated for wearing.

In the coating station application, the shank mechanism of a traditional CD actuator can be replaced, for example, with a magnetostrictive element, which can be used to locally adjust the stress of the coating blade. The method can also be used to adjust the coat weight in the machine direction. In that case, the stress of the blade beam is implemented by means of magnetostrictive loading elements, for example. A corre- sponding approach can also be applied to rod coating. For example, magnetostric- tive materials enable decreasing the mutual distances between the profiling CD actuators to as low values as possible in terms of production technology. For example, it is possible to make a profiling doctor blade, wherein the profile actuator of the blade, which is made of magnetostrictive material, is integrated with the body of the doctor blade.

One object of the invention is to provide nozzle structures. A fluid is conducted through the nozzle. Solid material can also be mixed with the fluid. The fluid can be, for example, drying gas, moistening mist, liquid used for washing or cleaning purposes, such as a solution, or gas, fibre suspension or coating mix or some other substance added into the pulp flow. Typical applications include blowing hoods, direct through drying machines, floating web-drying, steam boxes, moistening sprayers, a distribution system of the head box flow, a bypass manifold and a set of distribution tubes and various extruders. Adaptive material is used in the mecha- nism of the nozzle fitting assembly or in the actuators influencing the nozzle. When a magnetic field is exerted on the material in question, a desired deformation or movement of the nozzle can be provided by means of the dimensional changes in the material. The invention can be used to accurately control the adjustment of the orifice. Furthermore, location can be implemented without a separate feedback loca-

tion measurement data. One of the goals can also be to compensate for the wear of the nozzle material by adjusting the orifice.

One nozzle application is the head box slice, which can be used to control the ad- justment of the transverse profile of the grammage and of the slice jet. When run- ning different paper grades and grammages, the height of the slice is adjusted to provide a desired head box density. Normally, the transverse profile of the gram- mage is adjusted by bending by means of fine adjustment shafts, the end list that is attached by means of spring loading against the upper lip. The positioning of the end list is used to compensate for the effect of deflections of the upper and lower lips on the slice. The deflections are caused by various reasons. The intention is, by adjusting the end list, to affect the discharge profile by changing the slice, but, at the same time, changing the reach of the list causes a change in the necking and the an- gle of departure of the jet. Furthermore, the distance of the impact can also change in a harmful way. When the reach of the list and that of the lower lip increase, the change in the angle of departure decreases by the same change in the reach of the list. When suitably increasing the above-mentioned reaches simultaneously, the jet's angle of departure remains the same. Increasing the reach of the end list turns the jet downwards and, correspondingly, increasing the reach of the lower lip turns it up- wards. Adjustment of the reach of the lower lip traditionally takes place by moving the upper part of the lip channel to and fro. Using adaptive, such as magnetostrictive materials, the reach of both the end list and the lower lip can be adjusted and located at the same time. The feedback adjustment of the profile of the grammage or, for example, of the coat weight can be implemented using CD actuators made of mag- netostrictive material, when the appropriate quality measurements are in use.

In driers, such as blowing hoods or floating web-driers, the drying capacity can be optimised particularly, among others, by adjusting the orifice so that the heat- transfer coefficient of the nozzle remains optimal. In sprayer solutions, the orifice and the shape of the nozzle can particularly be adjusted to obtain a desired spray pattern on the target surface. In distribution and extruder solutions, the flow rate or flow profile in the nozzle or in the nozzle tip can be adjusted in particular.

Nozzle driers are usually designed so that the relative blowing surface (the nozzle surface/the target surface of blowing) is about 2-3 %. In this way, certain blowing capacity provides the highest value of the heat-transfer coefficient.

Slit nozzles have a lower optimum velocity than aperture nozzles, making the slit nozzle preferable for purposes, where a low force exerted on the web is advanta- geous, such as when drying coated paper.

For example, in float driers, paper is dried by means of a hot air jet that is blown from a nozzle to the surface of the web at a high velocity. Generally, the blast air is heated by means of gas burners or hot steam. The nozzles are placed alternately on both sides of the paper web, whereby the paper travelling through the drier floats supported by the air jets without touching the nozzles. The main types used in dry- ing coated paper are a vacuum nozzle or a foil nozzle and an overpressure nozzle or a float nozzle. In the vacuum nozzle, one air jet is blown between the web and the nozzle, whereby the web sets in a state of equilibrium at a distance of a few milli- metres from the nozzle in accordance with the Bernoulli principle. Correspondingly, two jets are blown from the overpressure nozzle against each other. The overpres- sure thus generated tends to push the web away from the nozzle. The propulsive force is compensated for by means of nozzles placed on the opposite side.

One object of the invention is to provide supporting structures, such as beams, bod- ies and shafts. These can be, for example, the blade and nozzle beams of a coating station, steam pipes and boxes, bodies of doctor blades, bearings and their support- ing structures, the structures of measuring systems, such as quality measurement systems, and bodywork, such as the bodies of a coating station or a calender. The invention can be used to particularly eliminate any bends in the supporting struc- tures, the transverse bend of the path in particular. Vibration can also be controlled according to the invention. <BR> <BR> <P>One object of the invention is to provide rotary members, such as rolls, e. g. , calen- der rolls, and cylinders, such as drying cylinders. The invention can also here be used to control the bend, the dimension or the shape of the object, any transverse bends or the profiled shape of the path in particular. The properties of roll surface material, such as viscoelastic properties, can also be controlled. The roll can also be coated with polymer.

One object of the invention is to provide non-rotating control means. This can be, <BR> <BR> for example, a non-rotating take-out roll or a bending or measuring beam (e. g. , after transverse measurement).

One object of the invention is to provide the shoe of a long nip, in a calender and pressing machine in particular. The shoe can fully or partially be made of magne- tostrictive material, whereby its dimensions, such as thickness, can be changed by means of a magnetic field. By arranging in the vicinity of the shoe a magnetic field <BR> <BR> consisting of narrow zones and being, e. g. , electrically controllable, the thickness profile can, in principle, be adjusted by means of a response of any narrowness.

Correspondingly, piezoelectric material can also be used here.

The shape, such as length, or movement of the shoe of a long nip, can also be ad- justed in the longitudinal direction of the path. In this way, the length of the shoe, such as the radial length in particular, can be adjusted especially in a calender nip.

The method is intended to effectively adjust the length of the shoe separately for each paper grade and place of operation. In that case, in a calender, for example, one shoe construction can be used to run various paper grades at all levels of linear load. The shape of the shoe can be adjusted actively, whereby the effective and ra- dial lengths of the shoe change. The method can be used to accurately control the adjustment of the shoe length without feedback.

One object of the invention is to provide revolving endless sections, such as belt- <BR> <BR> like structures, e. g. , wires or belts, such as polymer or metal belts. The belt can be, for example, in a belt calender. A metal belt, for example, can fully or partially be formed from adaptive material, whereby its properties and behaviour can be suita- bly controlled. One example is the control of the thickness profile of the belt in nip contact.

One object of the invention is to provide a crimp connection, a magnetic crimp con- nection in particular. It comprises expanding or decreasing sections, which are inter- locked with one another, during interlocking so, that the sections have room to be interlocked as desired. After interlocking, the dimensions of the sections are al- lowed to return, whereby the joint becomes tight. This can be used to replace ther- mal crimp connections or heating bolts in many objects. When a magnetic field is used, the magnet that produces the required field can be integral with the structure or it can be brought separately near the object of connection for the time of inter- locking.

One object of the invention is to provide nip structures. There are nip structures, for example, in calenders, rod coating stations and winders. In that case, the target can <BR> <BR> be to correct an uneven nip profile or an uneven nip load (e. g. , at the winder), pro-<BR> filing the web or controlling any problems with vibration (e. g. , in calender nips and when coating at high velocities). The adaptive material in the nip can either be in both rolls or in just one roll.

According to the invention, the transverse profile of the nip and the nip load can be adjusted during the run. The adjustment can be carried out, for example, by chang- ing the roll diameter (adjustable nip length), length (the oscillating movement) or the nip force (power adjustment and measurement in the nip). The winder can be used to profile the nip or oscillate or measure the power in the nip. Each nip in the calender can also be adjusted separately. The long nip press can also be adjusted and profiled.

Examples of further embodiments of the invention are described in the following.

The drawings are part of the written specification.

- Fig. 1 shows a section made of adaptive material, and its use in adjustment.

- Fig. 2 shows a doctor blade construction.

- Fig. 3 shows another doctor blade construction.

- Fig. 4 shows a slit nozzle construction.

- Fig. 5 shows a vacuum nozzle.

- Fig. 6 shows an overpressure nozzle.

- Fig. 7 is a cross-section of a nozzle body.

- Fig. 8 is a front view of the nozzle body of Fig. 7.

- Fig. 9 is a front view of a jet of the nozzle body of Fig. 7.

- Fig. 10 is a side view of the jet of Fig. 9.

- Fig. 11 is a front view of another jet of the nozzle body of Fig. 7.

- Fig. 12 is a side view of the jet of Fig. 11.

- Fig. 13 shows a nozzle beam provided with nozzle bodies according to Fig. 7.

- Fig. 14 shows a spray coverage pattern of the nozzle beam of Fig. 13.

- Fig. 15 shows a coating station application.

- Fig. 16 shows a box application.

- Fig. 17 shows a quality measurement system application.

- Fig. 18 shows the adjustment and control principles of deformations.

- Fig. 19 shows a roll application.

- Fig. 20 shows a roll nip application.

- Fig. 21 shows the adjustment of the thickness profile at a shoe calender.

- Fig. 22 shows a long nip application.

Fig. 1 shows how the dimension of a body made of adaptive material can be changed by means of magnetic or electric fields. The body consists of particles 2 and 3 of adaptive material. In the left-hand state, the particles are mainly randomly oriented. When a magnetic or electric field H is exerted on the body by means of a device 4, the tension o of the particles changes and the particles are at least partially oriented in accordance with the field, whereby the dimensions of the body change.

The change in the dimensions or the change of any parameter, which the dimen- sions of the section act on, can be monitored by means of measuring devices 5, and adjusting devices 6 can be used to adjust the intensity of the field to achieve the de- sired result.

Magnetostrictive materials, for example, have a response that is quick (e. g. , about 1<BR> kHz) and accurate (e. g. , an error of about 0.1 %).

The blade solution 7 according to Fig. 2 has a blade 8, which is supported on a body 10 by means of a blade holder 9. On one side of the blade at a distance from the tip 11 of the blade, there are magnetostrictive elements 12 and 13, which are connected to the blade by means of a connecting piece 14 in the transverse direction of the blade. Both elements have their respective associated magnets 15,16, which are attached to the body. One element can be used to bend the blade upward and the other to bend the blade downwards. A movement in the desired direction is pro- vided by conducting the magnetic field to a desired element or by adjusting the in- tensity of the magnetic fields. The structure can be used to replace the traditional attachment and loading mechanisms of the blade.

The solution 7.1 according to Fig. 3 has magnetostrictive elements 12.1, 13.1 on both sides of the blade 8.1, transverse projections 17,18 that directly affect the blade being provided at the ends of the elements. The elements are controlled by means of magnets 15.1 and 16.1.

The blade fitting can also have several adjustable elements in the transverse direc- tion thereof, or it can be continuous or of a shaft-type.

In Fig. 4, there is a nozzle 19 in the transverse direction of path, formed by lips 20 and 20'. The size of a slot 21 is d and the distance from the web h. The lips are made of magnetostrictive material and adjustable magnets 22 and 22'are connected to them. By changing the fields of the magnets, the size of the slot or its distance from the web can be adjusted. In this way, the flow can be influenced and particu- larly the heat transfer can be adjusted as desired.

In the vacuum nozzle 23 according to Fig. 5, the framework in the transverse direc- tion of the path comprises a hollow feeding beam 24 and attached to the side thereof an adjustable nozzle 25. Holes are provided between the beam and the nozzle. The nozzle has a vertical wall, the upper part 25'of which faces the beam. A nozzle opening 26 is formed between the upper part and the beam. Fluid, such as drying air, is conducted to the nozzle through the feeding beam, and from the nozzle fur- ther through the nozzle opening to the web running above. In the upper part of the nozzle, there is magnetostrictive material. By changing the magnetic field exerted on it, the size of the nozzle opening or its distance from the web can be adjusted.

The nozzle can be divided into several segments in the transverse direction, the seg- ments being separately adjustable.

The overpressure nozzle 23.1 according to Fig. 6 is provided with a nozzle 25.1 on both sides of the beam of the feeding beam 24.1, and at the upper end of the nozzle,

there is an adjustable nozzle opening 26.1 that is provided with an upper part 25.1' containing magnetostrictive material.

The nozzles are located in float boxes, which contain the necessary inlet and dis- charge channels. The fluid blown through the nozzle slots is removed from between the nozzles.

The periphery of the nozzle body 27 according to Figs. 7 and 8 is divided into sepa- rate segments 28, which are manufactured from magnetostrictive material. As each one of them can be separately adjusted, the shape of the response pattern of the noz- zle can be controlled. The segments are further attached to a separately adjustable flange 29, which is made of magnetostrictive material. Figs. 9-12 show some possi- ble shapes of the jet. Figs. 11 and 12 show a pattern formed by two ellipses that are superimposed crosswise; by arranging several of these patterns in an interlocked relationship, an as even as possible coverage is obtained (Fig. 14).

The nozzle beam 33 according to Fig. 13 has nozzle bodies 27 in three rows. Fig. 14 shows how these bodies can be used to provide a highly even surface coverage us- ing the jet according to Fig. 11. Similarly, profiling implemented by means of the nozzle beam can be controlled both in the transverse and the longitudinal direction of the path, as both all rows of nozzles and the individual nozzles pertaining to them can be controlled separately.

Fig. 15 shows a coating station application, wherein the straightness of a blade beam 34 is controlled by elements 36,37 and 38, which are attached to a blade sup- port rod 35 at three sides thereof and made of magnetostrictive material. The bend of the blade beam can be influenced adjusting the magnetic field that is conducted to the elements. The elements can be divided into separate zones a-n, which can be adjusted separately. Any corrections needed can be obtained from straightness measurement or deflection calculation. Fastness is also one special advantage of this application. For example, in a drive-on situation at the coating station, heat transfer from the paste to the beam structures causes sudden deformations (warping), which can thus be eliminated considerably faster than in traditional structures that are based on water heating only.

Fig. 16 shows a box application, a steam box application in particular. The straight- ness of the box 39 is influenced adjusting the magnetostrictive zone elements 40 and 41 on both sides of the blowing slit, which elements are divided into zones. For example, the end zones 40'and 41'can be designed so that any special problems occurring on the edge zones can be controlled. As any deformations caused by ther- mal expansion in particular can be controlled, the box can be located nearer the

web. A corresponding box can be used, e. g. , in drier (such as floating web or infra- red) and steam pipe structures.

Fig. 17 shows a quality measurement system application. The framework of the measurement beams 42 and 42.1 on both sides of the web employ two-zone magne- tostrictive material 44 and 45 on both sides of a transversely movable measuring head 43, so that the bend typical of the structures can be eliminated.

In that case, the location of the measuring head and the sensors contained by it can be carried out more accurately and the reliability of the measurements can be im- proved.

Fig. 18 shows a roll application. A ternary roll 46, such as a take-out roll, which is supported at its ends, employs magnetostrictive material. The zones 47,48 and 49 of the roll are made of magnetostrictive material. On each zone, near each end, above and below, there are adjustable magnets 50,51 and 52,53. In this way, the crowning of the roll can be adjusted. At the same time, the rigidity or balancing (static or dynamic) can be influenced. The roll can also be a guide roll, a spreader roll, a dancer roll, an impression roll or a thermo roll. Sets of rolls with one or more nips can also be made. For example, the loading of calender rolls can thus be sepa- rately adjustable.

Fig. 19 shows an adjusting and control principle, wherein the bends and any other deformation of a structure 53.1, which is supported at its ends, are determined on the basis of a bend measurement or an elongation measurement or some other meas- urement, so that, for example, the temperature values of the structure are taken into account in calculation. Corresponding to Fig. 18, the structure is three-zone. In unit 54, in the adjusting device or the calculation unit 55 pertaining to the system, such standard values are defined for the control units of the magnetostrictive elements <BR> <BR> (e. g. , for the magnetic fields) on the basis of measurements or calculations that the bend d'is minimized.

The adjusting principle according to Fig. 19 is also suitable for adjusting a non- rotating roll.

Fig. 20 shows a nip application 56 comprising a first roll 57 and a second roll 58, whereby there is adaptive, such as magnetostrictive material 59 on the surface of at least one roll, the dimensions of which material can be changed by means of a mag- netic field. The diameter of the roll can be changed by changing the thickness or the length of the adaptive material or the layer of material by means of a magnetic field.

The roll can be divided into segments in the axial direction, or the magnetic field exerted on the adaptive material can be changed in this direction, whereby the di-

mensions of the roll can be changed at different points of the roll. The web can also be oscillated using a roll that changes during the run, such as a lengthening and shortening roll.

In addition to the movement, adaptive material can be used to generate a force, whereby the nip load can be adjusted and measured directly in the nip.

At high velocities, the nip can be made to oscillate at a desired frequency, whereby the problem with vibration of the rolls decreases.

The bend of the rolls can also be compensated for.

The adjustment and feedback are easy to obtain by measuring the current and the voltage supplied.

The nip can be constructed, for example, so that each roll works as a coil, whereby a magnetic field is generated between them. On arriving at the magnetic field, the adaptive material reacts by expansion. In that case, the bigger roll in Fig. 20 can be a traditional roll and work as one coil. The other roll is coated with adaptive mate- rial and works as the other coil. By supplying current and voltage to the coils, the magnetic field H'can be changed, which in turn changes the shape h'of the roll surface coming to the nip.

Adaptive material can also be placed under the normal coating of the roll, or both rolls can be coated with adaptive material. The magnetic field can also change on different segments (profiling).

Fig. 21 shows the adjustment of the thickness profile in a shoe calender 60. The equipment has, under the web in its direction of movement, a shoe 61, over which a belt 62 revolves in the direction of the web's movement. A thermo roll 63 presses the web from above against the belt and the shoe. After the calender, there is a cal- liper profiler 64.

The shoe 61 is made of magnetostrictive material. In the cross direction of the path, the shoe has several electromagnetic coils 65 (e. g. , at 50-100 mm intervals), and the intensity of the magnetic field of each coil can be adjusted separately by changing the current conducted to the coil. The magnetic field of each coil changes the thick- ness of the shoe locally. Each coil is adjusted by means of the data obtained from the measured thickness profile 66 by means of adjusting equipment 67.

Fig. 22 shows the longitudinal adjustment of the shoe 68 of the long nip. Inside the shoe, there are two elements 69 and 70, which are superimposed at a distance from one another and which are curved in the longitudinal direction and are of the same width as the nip, and which are made of magnetostrictive material. In this way, the

shape of the elements can be adjusted actively by means of adjustable magnets that are suitably located. At the end of each element, there is an adjustable magnet 71, 72, which is adjusted by means of equipment 73. The mix properties of the elements are chosen so that by conducting magnetic fields to the elements or by adjusting the intensity of the magnetic fields, a movement in the desired direction and a force are provided in the shoe. In that case, the geometry (the radius) of the shoe and the ef- fective length 12 of the shoe change. The magnetostrictive elements can also be placed in the shoe so that the length of the shoe changes directly on the horizontal plane. According to the invention, both the length and the curvature and other di- mensions of the shoe can be controlled.

In the shoe 68, the length can be adjusted, per each paper grade separately, the op- timal shoe length at each point of the linear load, taking into account the velocity of the machine and, for example, the surface temperature of the thermo roll. Thus, the optimal nip length, pressure level, shape of the pressure impulse and the retention time in the nip can always be defined grade-specifically.

As the magnets 71 and 72 of the shoe 68 on the inlet side and the trailing side can be adjusted separately, it is also possible to adjust the tilt of the shoe (tilt adjust- ment).

All properties provided in the shoe 68 can be integrated with a control strategy, which is used to obtain as good as possible quality properties of paper (thickness, glare, bulk). The adjustment strategy can be combined with the machine control automation so that in all situations, where the shoe length changes, the basic func- tions of the shoe (e. g. , oil supply and pressure control) are ensured.