ROLL OF LOW-WEIGHT CONSTRUCTION AND METHOD FOR MANUFACTURE OF THE ROLL

Abstract: The invention concerns a roll of low-weight construction for a paper or board machine or for a paper or board finishing device. The roll frame of the roll (10) comprises a cylindrical mantle (11) with thin walls and a core part (12), which fills said cylindrical mantle fully or at least partly and which has been made of a filler material that has a low weight but that endures loading in the press direction well. The invention also concerns a method for manufacture of the roll.

Description: Roll of low-weight construction and method for manufacture of the roll The invention concerns a roll of low-weight construction for a paper or board machine or for a paper or board finishing device. The invention also concerns a method for manufacture of a roll of low-weight construction for a paper or board machine or for a paper or board finishing device. In paper machines and paper finishing devices, there is a need to provide a roll of low-weight construction that endures loads. Such a need is manifested with emphasis, for example, in modernization of supercalenders, because, in connection with modernization, it is desirable to replace the fibre rolls that were used earlier in such supercalenders by modern polymer-coated rolls. When a new supercalender is being constructed, such a problem does not occur, because the rolls and the frame construction can be designed so that they are well compatible with each other right from the beginning. A modern supercalender includes a large number of polymer-coated rolls, in which the roll frame is most commonly made of a relatively thick steel mantle. It is, however, not possible to fit such a roll in place of an earlier fibre roll in all old supercalenders, because the set of rolls would be excessively heavy for the existing frames and other equipment. Such rolls with low-weight construction substituted for fibre rolls have been described earlier, e.g., in the DE publications 19 511 595 and 19 533 823 and in the EP publication 735,287, which publications deal with polymer-faced calender rolls that have been formed so that the axle of the old fibre roll is utilized in the roll so that, onto the roll axle, in place of the fibre disks, disks made of aluminum material by casting and turning are fitted, which disks, in view of achieving a sufficiently low weight, consist of cellular material with thin walls, in which at least some of the walls that form the cells extend in the radial direction of the roll. Then, onto these disks, an elastic polymer coating has been fitted. The roll thus formed has quite good properties, above all because the weight of the roll has been made so low that it can be used readily in renewals of supercalenders, because the difference in weight of the roll as compared with a fibre roll is very little. However, a significant drawback of these rolls is very high cost. The high cost again results from the technique of manufacture that is used, which requires casting and machining of the disks. As one alternative solution, these publications suggest manufacture of the disks out of a material that contains reinforcement fibres, such as epoxy reinforced with fibreglass, carbon fibres, aramide fibres, or equivalent. Such solutions are, of course, usable in themselves, and with them a roll with a construction of quite low weight is obtained, but a problem is an even higher cost. In nip rolls, a further problem is generally the load bearing capacity in the direction of the nip plane. For example, in supercalenders, the intermediate rolls form two nips in the nip plane, i.e. they are "pressed" from opposite directions. It is a result of such loading that the roll mantle becomes flat, i.e. the shape of the roll becomes oval. However, since, in polymer rolls, the roll ends have been attached fixedly to the roll mantle, the roll cannot be flattened over its entire axial length in the same way, but the roll is circular in its end areas. From the point of view of the calendering profile, this is quite troublesome. In nip rolls, it should be a definite aim that flattening of the roll is excluded completely, which is in many cases quite difficult to achieve, or that the flattening is uniform over the entire axial length, in which case the profile of linear load in the nip can be made uniform. In rolls that form a nip, in particular in modern centre rolls of the press sections in paper machines, which rolls have been made commonly out of a tubular roll mantle and of a suitable coating fitted onto the roll mantle, it is a problem that shell oscillation occurs in the roll. This shell oscillation may cause barring in the felts, which is again copied along with the paper to the calender rolls. In massive rock rolls, which were used earlier, shell oscillation did not occur to a corresponding extent. Thus, it ought to be possible to construct a roll so that shell oscillation of said sort can be prevented. Moreover, rolls of low-weight construction are needed in paper machines and in paper finishing devices in a number of different applications, e.g. , as paper alignment and guide rolls and equivalent. The object of the present invention is to eliminate the above problems and drawbacks related to the prior art and, further, to provide a novel roll and a method for manufacture of a roll of low-weight construction. In view of achieving these objectives, the roll in accordance with the invention is mainly characterized in that the roll frame comprises a cylindrical mantle with thin walls and a core part, which fills said cylindrical mantle fully or at least partly and which has been made of a filler material that has a low weight but that endures loading in the press direction well. On the other hand, a first embodiment of the method in accordance with the invention is mainly characterized in that the roll frame of the roll is formed so that a cylindrical mantle with thin walls is manufactured and that the cylindrical mantle is filled fully or at least partly with a filler material that has a low weight but that endures loading in the press direction well, said filler material constituting the core part of the roll. In a corresponding way, a second embodiment of the method in accordance with the invention is mainly characterized in that the roll frame of the roll is formed out of an axle made of a tubular or solid material, out of a filler material which is fixed onto the axle, which has a low weight but endures loading in the press direction well and which forms the core part of the roll, and out of a cylindrical mantle with thin walls surrounding the core part. By means of the invention, a number of significant advantages are obtained as compared with the prior art, and, of these advantages, for example, the following can be stated. The method in accordance with the invention is very simple and easy to carry out, and, among other things, out of this reason a roll manufactured in accordance with the method is of very low cost, as compared with the rolls currently in use. A roll manufactured in accordance with the invention endures bending in compliance with the application of use that it has been intended for, and further, the roll receives loads in the press direction very well. If necessary, the roll can be constructed as of very low weight, in which case it can be used in a number of different applications in paper machines. Of the advantages that can be obtained with different embodiments of the invention, in the form of a catalogue, further, the following can be stated. As was already stated above, depending on the filler material used in the roll, a construction of very low weight is obtained. These materials of particularly low weight can be employed in particular in rolls with multi-layer plate construction. It is a highly significant further advantage that the construction of the frame of the roll can be made fully homogeneous across the entire length of the roll. In rolls with multi-layer plate construction in which an inner tube and an outer tube or an equivalent outer wall as well as a filler material fitted between said tubes or walls are used, a construction can be obtained in which the end flanges of the roll can be omitted completely. In such a roll construction, which is intended in particular for calenders, the roll can be deformed in the same way across the entire axial length of the roll. In particular in consideration of a calendering process, the advantage that is obtained is significant, for in calendering, the end flanges are exclusively detrimental as a result of edge compression, crown formation arising from heat, etc. detrimental effects. In particular, in a construction with no end flanges, as the starting point of the dimensioning of the roll can be adopted the strength of the coating of the roll, in stead of the requirement of an equally little flattening of the tubular roll mantle as a result of the non-existent flattening of the massive end flanges. This again provides the advantage that the tubular roll mantle can be made even thinner, which reduces the weight of the roll further. For the roll frame, a more extensive flattening of the roll frame can be permitted than in the prior art, which results, in the case of a nip roll, in a more extended nip, in longer nip times, in a lower maximal pressure with a certain load or, inversely, in a higher linear load with a certain level of maximal pressure. In a roll solution with no end flanges, a construction is achieved which has no weld joints, bolt joints or tight fittings. Attenuation of vibrations in a roll with multi-layer plate construction can be accomplished readily, and the roll does not involve detrimental shell oscillation. From the point of view of the process of manufacture, the roll in accordance with the invention is simple, among other things, because, when a wound composite tube is employed at least as the outer tube, steps of manufacture of the roll frame can be combined with steps of coating. The bending arising from the own weight of the roll can be regulated readily by means of dimensioning of the surface plates and the filler material in a roll with multi-layer plate construction, by means of choice of materials, and, when composite materials are used, by means of choice of the fibre orientations. The roll in accordance with the invention is very well suited for use in connection with modernization of equipments and devices. Owing to the low- weight construction, balancing of the roll is also easy. Of possible applications of use of the rolls can be stated, among other things, intermediate rolls in supercalenders, various rolls that require heating, centre rolls in press sections, various guide and alignment rolls, and equivalent. The further advantages and characteristic features of the invention will come out from the following detailed description of the invention. In the following, the invention will be described by way of example with reference to the figures in the accompanying drawing. Figure 1 is a fully schematic illustration of a first embodiment of the roll manufactured by means of the method in accordance with the invention. Figures 2A and 2B are schematic illustrations as a sectional view and as a side view in part of a further embodiment of the roll in accordance with the invention. Figures 3...9 show further embodiments of the roll in accordance with the invention. In Fig. 1, the roll is denoted generally with the reference numeral 10. The frame of the roll 10 consists of a cylinder 11 with thin walls or of a corresponding cylindrical mantle and of a filler material 12 that fills said cylinder 11. According to a preferred embodiment, the cylindrical mantle 11 is made of a metal material, in particular steel. For the manufacture of the cylindrical mantle, it is also possible to use some other material, in stead of a metal material, and as one alternative solution is suggested manufacture of the mantle out of a composite material, in particular when the roll frame is used, for example, as the frame of rolls with soft coatings in a multi-roll calender. To the roll frame, which consists of the cylindrical mantle 11 and of the filler material 12, rolls ends 14 and axle journals 15 have been attached in a suitable way. Further, the roll may be provided with a coating 13, which can be constructed in the desired way in respect of the material and other properties. As regards the method of manufacture, the invention is very simple. The manufacture of the roll frame is carried out in two stages, so that first a cylindrical mantle 11 with thin walls is manufactured out of the desired material suitable for the application of use. In the second stage, this cylindrical mantle 11 is filled completely or at least partly with a material that has a low weight but that endures loading in the press direction very well. The filling of the cylindrical mantle 11 is carried out by casting, and the filler material is advantageously concrete. The cylindrical mantle 11 is measured exclusively in accordance with the requirement of bending of the roll 10, in which case a very thin cylindrical mantle 11 of low weight is obtained. The load applied to the roll 10 in the press direction is taken care of by means of the filler material 12, so that flattening of the roll mantle 11 is prevented, for example, by passing a nip load directly through the roll 10 from one side to the other when the roll 10 is used, for example, as an intermediate roll in a supercalender. This passing of the load through the roll 10 is carried out by means of the filler material 12. The filler material 12 can be optimized in respect of the cost and the weight, in which case concrete is a very good and usable alternative. The concrete can also be internally reinforced concrete, in particular fibre-reinforced concrete, in order that it should also tolerate a certain extent of bending. The whole of the roll frame consisting of a cylindrical mantle 11 and of filler material 12 can be manufactured without roll ends 14, in which case, as required, in the manufacture a pre-stressed tube can be formed whose deflection is little. The roll ends 14 are added to the roll frame in a later stage. As is shown in Fig. 1 further, the roll 10 may be provided with a coating 13. Since a roll 10 manufactured in accordance with the invention is suitable for use in a number of different applications of use, the roll coating 13 must, of course, be chosen in accordance with this application. When the roll 10 is used, for example, as an intermediate roll in a supercalender, the coating 13 is made of a polymer material. When the roll 10 is used, for example, as the centre roll in a press section, the coating must be suitable for this purpose, in which case, as the material of the coating 13, it is possible to use a ceramic material, metal-ceramic, or equivalent. The method of manufacture in accordance with the invention can be modified very easily for manufacture of rolls of different types, and one such usable solution is illustrated in Figs. 2A and 2B. In Fig. 2A, the roll is denoted generally with the reference numeral 20, and, similarly to Fig. 1, the roll frame of the roll comprises a cylindrical mantle 21, which is preferably fully, or at least partly, filled with a filler material 22, advantageously concrete. The roll 20 as shown in Fig. 2A is meant to be used as a heatable roll, in which case the material of the cylindrical mantle 21 is preferably steel, and it is, for example, either shell hardened or provided with a suitable hard coating, for example ceramic or metal-ceramic coating. Further, into the interior of the cylindrical mantle 21, pipes 26 extending substan- tially in the axial direction of the roll have been fitted, which pipes have been fitted in the interior of the cylindrical mantle 21 preferably in connection with the casting of the filler material 22 and fixed to the inner face of the cylindrical mantle 21. The roll 20 is supposed to be heated by means of a heat transfer medium, such as water or steam, and said heat transfer medium is meant to flow in the pipes 26. When the roll 20 is supposed to operate as a metal-mantle heatable roll, between the filler material 22 of concrete and the metallic cylindrical mantle 21, an insulation layer which tolerates high temperatures and pressures well, for example a ceramic insulation layer (not shown), can be fitted before casting of the concrete. In Fig. 2B, it is illustrated further how the heat transfer medium is introduced into the finished roll. For the introduction of the heat transfer medium, a duct or bore has been formed into the axle 25, and similarly, into the roll end 24, a necessary system of ducts 27 has been formed, which communicates with the bore formed into the axle 25, on one hand, and with the pipes 26 fixed to the inner face of the cylindrical mantle 21, on the other hand. Further, to the end of the axle 25, a water or steam coupling 28 or equivalent has been connected, by whose means the heat transfer medium is passed to the roll. It can also be considered that the heating of the roll 20 is carried out in some other way, in stead of a heat transfer medium. It is one solution, for example, that electric resistors are fitted in the pipes 26, in which case the roll 20 is heated by means of electricity. Induction can also be used as the mode of heating. Fig. 3 shows a further embodiment of a roll in accordance with the invention, which is denoted generally with the reference numeral 30. In this embodiment, the roll 30 has been manufactured as of a multi-layer plate construction so that the roll frame consists of two coaxial tubes 31,35 fitted one inside the other, between which tubes a filler material 32 has been fitted, which constitutes the core material and fills the space between the tubes 31,35 fitted one inside the other. In this roll 30 of multilayer plate construction, similarly to normal multi-layer plate constructions, the surface plates, i.e. in this case the outer tube 31 and the inner tube 35, bear the loads, and the low- weight filler material 32 gives the construction a high inertia. As the material of the outer tube 31 that forms the cylindrical mantle of the roll, it is possible to use strong materials suitable for the purpose, such as composite materials, steel, aluminum, or equivalent materials. The same materials are also suitable for materials of the inner tube 35. Further, as is shown in Fig. 3, the roll may be provided with a coating 33 suitable for the purpose, which has been con- structed in the desired way in respect of the material and other properties. As is shown in Figs. 3 and 4, the roll 30 in accordance with this embodiment has been constructed so that the conventional end flanges of the roll are missing entirely. In such a case, the inner tube 35 can be used as the axle of the roll 30, in the way shown in Fig. 4, from which axle the roll is mounted by means of the bearings 39. If necessary, the inner tube 35 can be substituted for by an axle made of fully solid material. Figs. 5 and 6 show a further embodiment of a roll 30 as shown in Figs. 3 and 4. The roll 30 shown in Figs. 5 and 6 is in the other respects similar to the solution shown in Figs. 3 and 4, with the exception that in said embodiment as shown in Figs. 5 and 6 the inner tube 35a does not extend substantially beyond the axial length of the outer tube 31 in the axial direction. The mounting and joumalling of such a roll on the frame constructions can be accomplished, for example, in the way illustrated fully schematically in Fig. 6 by means of seats 35b fully separate from the roll, which seats are attached to the inner tube 35a in the roll frame. The construction and the principle of operation of such a seat 35b can be favourably, for example, similar to that described in the applicant's earlier US Patent No. 5, 679, 108. The seat of mounting and joumalling described in said US publication is in itself related to reeling_and winding of a paper web, and not to joumalling of rolls in a paper machine, but by means of said construction, it is, however, possible to obtain significant advantages also in connection with a roll construction in particular when replacements of rolls have to be carried out as a routine operation, as is the case, for example, in calenders. Such joumalling and mounting accomplished by means of seats can also be applied in the construction as shown in Figs. 3 and 4. A roll as shown in Figs. 3...6 can be manufactured favourably so that, as the starting point, the inner tube 35,35a is taken, which operates as the axle of the roll. The tube can also be substituted for by an axle of solid material. In order to obtain a sufficiently low weight, it is, however, preferable, in stead of solid material, to use a tube, whose material can be, for example, a metal, plastic, carbon fibre, fibreglass, or some other composite material. In the manufacture, onto the tube 35,35a, the filler material 32 is cast/fixed, which material 32 operates as the core material of the multi-layer plate construction. The casting/fixing of the filler material takes place preferably when the axle tube 35,35a is positioned vertically, in which case the bending of the tube by the effect of its own weight is zero and does, thus, not constitute any problems. As the core or filler material 32, a material is used which is of low weight and which endures loading well, for example syntactic foam. As the filler material 32, it is also possible to use a suitable cellular material. After casting/fixing of the filler material 32, the mould, which may have been used for the casting, is disassembled from around the blank, and the outer face of the blank is turned in a lathe to make it coaxial with the axle tube 35,35a. After turning, the other surface plate of the multi-layer plate construction, i.e. the outer face, which forms the cylindrical mantle 31 of the roll, can be wound onto the filler material 32 in the same way as in a normal process of coating of a polymer roll. The cylindrical mantle tube 31 wound onto the filler material 32 can be used directly as a base for a polymer coating 33. The manufacture of the roll can also be carried out so that first the inner and outer tube 35,31 of the roll frame are made fully complete. These can be made, for example, by winding, or it is possible to use prefabricated tubes made, for example, of a metal or of some other suitable material. The prefabricated inner and outer tubes 31,35 are fitted precisely coaxially one inside the other, and the filler material 32 that operates as the core material is cast between the tubes 31,35. Of different methods of manufacture of the roll, further, the following variations can be suggested. First, filling of the outer tube or cylindrical mantle of the roll or manufacture of the roll frame in a mould can be carried out by means of centrifugal casting. In such a case, the manufacture can take place in the vertical position or horizontally either as a continuous casting that fills the mould or, alternatively, as layers. As an advantage of casting taking place layer by layer, it is possible to mention the control of the reaction heat of the resin that is used so that the thermal energy that has been produced in the reaction of curing has time to be removed at least partly between casting of the different layers. The casting of the roll frame can also be carried out in the direction of the axis of the mould layer by layer or as continuous casting so that rapidly hardening resins are utilized in the manufacture. The roll can also be constructed so that the inner tube is omitted completely. Such embodiments are illustrated, for example, in Figs. 7 and 9, in which the roll is denoted generally with the reference numeral 40. In such an embodiment, first the outer tube 41 that forms the cylindrical mantle of the roll is manufactured, and said tube is then filled with the filler material 42 by casting. The manufacture can also be carried out so that a separate outside mould is used, which is filled with the filler material 42 by casting. After this, said outside mould is removed, and the cylindrical mantle 41 of the roll is formed onto the filler material 42, for example, by winding. Further, after this, the roll can be coated with a purposeful coating material. Into the roll frame thus manufactured, the seats for the axle journals 45 (Fig. 7) or for the bearings 49 (Fig. 9) are machined, and said axle journals 45 / bearings 49 can be fixed to the fastening points formed into the filler material 42, e.g. , by gluing. By means of a roll construction as shown in Figs. 3...7 and 9, a construction of very low weight is achieved, which is fully homogeneous from end to end in the roll. The end flanges of the roll are entirely unnecessary, for the inner tube in the roll frame can, when necessary, operate as the axle journal, or the joumalling of the roll can be carried out by means of the inner tube by the intermediate of separate seats. In a construction with no inner tube, the axle journals or bearings can be fixed directly to the filler material. In calender operation or from the point of view of the calendering process, the end flanges of the roll would be exclusively detrimental because of lateral compression, crown formation as a result of heat, etc. detrimental effects. As the starting point of the dimensioning of a roll manufactured without end flanges in the way described above, it is possible to adopt the strength of the roll coating, in stead of a requirement of an equally little flattening of the roll mantle as a result of the non-existent flattening of the end flanges of solid material. Fig. 8 still shows a further alternative solution of the roll in accordance with the invention. In Fig. 8, the roll is denoted generally with the reference numeral 50. In the solution of this embodiment, the cylindrical mantle of the roll is formed first out of a tube 51 with thin walls, whose material can be a metal, plastic, fibreglass or carbon fibre, or equivalent. Then, the cylindrical tube 51 of the roll is filled with tubes 52a of thin walls and of very small diameters, as compared with the diameter of the cylindrical tube 51 , which tubes 52a are fitted substantially in the axial direction of the roll. The material of these small-diameter tubes 52a is, for example, metal, plastic, carbon fibre, or equivalent. Said tubes 52a are cast together with each other with a suitable medium, for example glue, metal, concrete, resin, micro- globules, or an equivalent material. In such a case, said tubes 52a together with the medium that binds them together form the filler material 52 in the roll frame. Thus, by means of the solution as shown in Fig. 8, a low-weight construction is achieved, which is very rigid and which endures loading very well, as compared with the weight of the roll 50, in which construction, moreover, the channels formed by the longitudinal tubes 52a can be used, for example, for passing a heat transfer medium. Thus, the roll 50 as shown in Fig. 8 can be used, e.g., as a heatable roll in a calender. On the other hand, the medium circulating in the tubes 52a can be used for cooling of the roll 50 or for equalizing the temperature, which can be the case in calenders in the case of polymer rolls. So, the roll 50 can be provided with a coating in a way similar to what has been described in relation to earlier embodi- ments. By means of choice of materials and dimensioning of the cylindrical mantle tube 51 and of the small-diameter tubes 52a included in the filler material 52, it is possible to affect the rigidity and the weight of the roll 50, i.e. the bending of the roll by the effect of its own weight, efficiently. By affecting the bending, it is possible to manufacture, for example, such rolls with uniform bending as are used in modem calenders of certain types. The fixing and joumalling of a roll as shown in Fig. 8 on the frame constructions can be accomplished, for example, in a way similar to those described in relation to earlier embodiments. As one example of these can be stated the constructions as shown in Figs. 3...6, in which an inner tube that forms the axle of the roll is used. Above, the invention has been described by way of example with reference to the figures in the accompanying drawing. The invention is, however, not supposed to be confined to the exemplifying embodiments shown in the figures alone, but different alternative embodiments of the invention can show variation within the scope of the inventive idea defined in the accompanying patent claims.

Claims: Claims 1. A roll of low-weight construction for a paper or board machine or for a paper or board finishing device, characterized in that the roll frame of the roll (10;20;30;40; 50) comprises a cylindrical mantle (11;21;31;41;51) with thin walls and a core part (12;22;32;42;52), which fills said cylindrical jmantle fully or at least partly and which has been made of a filler material that has a low weight but that endures loading in the press direction well. 2. A roll as claimed in claim 1, characterized in that, to the ends of the roll frame, end flanges (14;24) provided with axle journals (15;25) have been fixed in view of joumalling of the roll. 3. A roll as claimed in claim 1, characterized in that, into the core part (32) of the roll, an axle (35;35a) has been fitted, which extends coaxially with the cylindrical mantle (31) of the roll through the roll (30), so that said axle (35;35a), together with the core part (32) and the cylindrical mantle (31) of the roll frame, forms a multilayer plate construction. 4. A roll as claimed in claim 3, characterized in that the roll axle (35) extends axially to outside each end of the roll, and that the roll (30) has been mounted on support constructions from said axle. 5. A roll as claimed in claim 3, characterized in that the axle (35a) of the roll is a hollow tubular axle (35; 35a), from which the roll can be mounted on the support constructions by means of seats (35b) which are separate from the roll itself and which are attached to said tubular axle. 6. A roll as claimed in claim 1, characterized in that, for the purpose of joumalling of the roll (40), axle journals (45) have been fixed directly into the core part (42) of the roll frame, into each end of the roll, into locations that have been machined into the core part. 7. A roll as claimed in claim 1, characterized in that, into each end of the roll (40), for the purpose of joumalling of the roll, spaces have been machined into which the roll bearings (49) have been installed. 8. A roll as claimed in any of the preceding claims, characterized in that the thickness of the cylindrical mantle (11;21;31;41;51) has been dimensioned in compliance with the requirements of bending of the roll, and that the filler material that forms the core part (12;22;32;42;52) of the roll and the filling ratio of the cylindrical mantle (11;21;31;41;51) have been dimensioned in compliance with the load applied to the roll in the press direction. 9. A roll as claimed in any of the preceding claims, characterized in that the cylindrical mantle (11;21;31;41;51) has been made of a metal material, in particular steel. 10. A roll as claimed in claim 9, characterized in that the outer face of the cylindrical mantle (11;21;31;41;51) has been shell hardened. 11. A roll as claimed in any of the claims 1 to 8, characterized in that the cylindri- cal mantle (11;21;31;41;51) has been made of a composite material, such as fibreglass, carbon fibre, or equivalent. 12. A roll as claimed in any of the preceding claims, characterized in that the filler material that forms the core part (12;22;32;42) of the roll frame is concrete. 13. A roll as claimed in any of the preceding claims, characterized in that the filler material that forms the core part (12;22;32;42) of the roll frame is internally rein- forced concrete, in particular fibre-reinforced concrete. 14. A roll as claimed in any of the claims 1 to 11, characterized in that the filler material that forms the core part (12;22;32;42) of the roll frame is syntactic foam. 15. A roll as claimed in any of the claims 1 to 11 , characterized in that the filler material that forms the core part (12;22;32;42) of the roll frame is PNC foam. 16. A roll as claimed in any of the claims 1 to 11, characterized in that the filler material that forms the core part (12;22;32;42) of the roll frame is aluminum foam. 17. A roll as claimed in any of the preceding claims, characterized in that, in connection with the casting of the filler material (12;22;32;42), inside the cylindrical mantle (11;21;31;41) of the roll frame, pipes (26) have been fitted, which extend substantially in the axial direction of the roll frame from end to end in the roll frame and which have been attached to the inner face of the cylindrical mantle (11;21). 18. A roll as claimed in claim 17, characterized in that a heat transfer medium, such as hot water or steam, has been arranged to circulate in the pipes (26) in order to heat the roll. 19. A roll as claimed in claim 17, characterized in that, in the pipes (26), electric resistors or equivalent heating elements have been fitted in order to heat the roll. 20. A roll as claimed in any of the claims 1 to 11 , characterized in that the filler rnaterial that forms the core part (12;22;32;42) of the roll frame consists of a cellular material. 21. A roll as claimed in any of the claims 1 to 11, characterized in that the core part (52) of the roll frame consists of tubes (52a) of small diameter, as compared with the diameter of the cylindrical mantle tube (51), and thin walls and fitted as parallel to the axis of the cylindrical mantle tube (51), with which tubes (52a) the cylindrical mantle tube (51) of the roll has been filled substantially completely. 22. A roll as claimed in claim 21, characterized in that the small-diameter tubes (52a) with thin walls which constitute the core part (52) of the roll frame have been fixed to each other by casting by means of a medium, such as glue, plastic, metal, concrete, resin and micro-globules, or a material of equivalent type. 23. A roll as claimed in claim 21 or 22, characterized in that a heat transfer medium has been made to flow in the tubes (52a) that constitute the core part (52) of the roll frame. 24. A roll as claimed in any of the preceding claims, characterized in that the cylindrical mantle (11;21;31;41;51) is provided with a hard coating, in particular a ceramic coating, a metal-ceramic coating, or equivalent. 25. A roll as claimed in any of the preceding claims 14 to 24, characterized in that, between the cylindrical mantle (11;21) of the roll and the filler material (12;22), an insulation layer that tolerates high temperatures and pressure has been fitted. 26. A roll as claimed in claim 25, characterized in that the insulation layer is made of a ceramic material. 27. A roll as claimed in any of the claims 14 to 20, characterized in that the cylindrical mantle (11;21) of the roll is provided with a polymer coating. 28. A method for manufacture of a roll of low- weight construction as claimed in any of the preceding claims for a paper or board machine or for a paper or board finishing device, characterized in that the roll frame of the roll (10;20;30;40;50) is formed so that a cylindrical mantle (11;21;31;41;51) with thin walls is manufactured and that the cylindrical mantle (11;21;31;41;51) is filled fully or at least partly with a filler material (12;22;32;42;52) that has a low weight but that endures loading in the press direction well and that constitutes the core part of the roll. 29. A method as claimed in claim 28, characterized in that the cylindrical mantle (11;21;31 ;41;51) of the roll (10;20;30;40;50) is dimensioned in compliance with the requirements of bending of the roll,_and the filler material (12;22;32;42;52) in the roll is dimensioned in compliance with the press load applied to the roll. 30. A method as claimed in claim 28 or 29, characterized in that the filling of the cylindrical mantle (11 ;21 ;31 ;41 ;51) with the filler material is carried out by casting. 31. A method as claimed in claim 30, characterized in that the casting is carried out when the cylindrical mantle (11;21;31;41;51) is in the vertical position. 32. A method as claimed in any of the claims 28 to 31, characterized in that roll ends (14;24) ιnd axle journals (15;25) are attached to the roll frame that has been formed. 33. A method as claimed in any of the claims 28 to 31, characterized in that, before the filler material is cast, into the cylindrical mantle (31) of the roll, an axle (35;35a) of tubular or solid naterial is fitted, which extends coaxially with the cylindrical mantle (31) of the roll through the roll (30), so that said axle (35;35a), together with the core part (32) and the cylindrical mantle (31) of the roll frame, forms a multi-layer plate construction. 34. A method for manufacture of a roll of low-weight construction as claimed in any of the claims 1 to 27 for a paper or board machine or for a paper or board finishing device, characterized in that the roll frame of the roll (10;20;30;40;50) is formed out of an axle (35;35a) made of a tubular or solid material, out of a filler material (32) which is fixed onto the axle, which has a low weight but endures loading in the press direction well and which forms the core part of the roll, and out of a cylindrical mantle (31) with thin walls surrounding the core part. 35. A method as claimed in claim 34, characterized in that the filler material (32) that forms the core part of the roll is fixed to the axle (35; 35a) while the axle is in the vertical position. 36. A method as claimed in claim 34 or 35, characterized in that the fixing of the core part of the roll to the axle (35;35a) is carried out in an outside mould, after fixing the mould is disassembled, the outer face of the core part (32) is machine Lso that it becomes coaxial with the axle, and the cylindrical mantle (31)_is_fixed onto the core part. 37. A method as claimed in any of the claims 28 to 36, characterized in that the cylindrical mantle (11;21;31 ;41;51) is made of a metal material, in particular steel. 38. A method as claimed in claim 37, characterized in that the outer face of the cylindrical mantle (11;21;31;41;51) of the roll frame is shell hardened. 39. A method as claimed in any of the claims 28 to 36, characterized in that the cylindrical mantle (11;21;31;41;51) is made of a composite material by winding. 40. A method as claimed in any of the claims 28 to 39, characterized in that concrete is used as the filler material (12;22;32;42). 41. A method as claimed in any of the claims 28 to 40, characterized in that, as the filler material (11;21;32;42), internally reinforced concrete, in particular fibre- reinforced concrete, is used. 42. A method as claimed in any of the claims 28 to 39, characterized in that the _filler material (12;22;32;42) is syntactic foam. 43. A method as claimed in any of the claims 28 to 39, characterized in that the fille^material (12;22;32;42) is PNC foam. 44. A method as claimed in any of the claims 28 to 39, characterized in that the filler material (12;22;32;42) is aluminum foam. 45. A method as claimed in any of the claims 29 to 44, characterized in that, in connection with the casting of the filler material (22), into the interior of the cylindrical mantle (21) of the roll frame, pipes (26) are fitted, which extend substantially in the axial direction of the roll frame from end to end in the roll frame and which are attached to the inner face of the cylindrical mantle (21). 46. A method as claimed in any of the claims 28 to 39, characterized in that the filler material (12;22;32;42) is composed of a cellular material. 47. A method as claimed in any of the claims 28 to 39, characterized in that the core part (52) of the roll frame is composed of tubes (52a) of small diameter, as compared with the diameter of the cylindrical mantle tube (51), and thin walls and fitted as parallel to the axis of the cylindrical mantle tube (51), with which tubes (52a) the cylindrical mantle tube (51) of the roll is filled substantially completely. 48. A method as claimed in claim 47, characterized in that the small-diameter tubes (52a) with thin walls which constitute the core part (52) of the roll frame are fixed to each other by casting by means of a medium, such as glue, plastic, metal, concrete, resin and micro-globules, or a material of equivalent type. 49. A method as claimed in any of the claims 28 to 48, characterized in that the roll frame is provided with a coating (13;33) fixed onto the cylindrical mantle (11;21;31;41;51). 50. A method as claimed in claim 49, characterized in that the coating (13;33) is a polymer coating. 51. A method as claimed in claim 49, characterized in that the coating (13;33) is a ceramic coating, a metal-ceramic coating, or equivalent. 52. A method as claimed in any of the claims 28 to 51, characterized in that, when the roll to be manufactured is supposed to operate as a heatable metal-mantle roll, in connection with the manufacture, between the filler material in the roll and the metallic cylindrical mantle, an insulation layer that tolerates high temperatures and pressure well is fitted before the filler material is cast. 53. A method as claimed in claim 52, characterized in that the insulation layer is made of a ceramic material.

Inventors: KOIVUKUNNAS PEKKA, LAITILA JYRKI, LUMPPIO KARI, VILJANMAA MIKA, KOIVUKUNNAS, PEKKA, LAITILA, JYRKI, LUMPPIO, KARI, VILJANMAA, MIKA
Applicants: KOIVUKUNNAS PEKKA, LAITILA JYRKI, LUMPPIO KARI, VALMET CORP, VILJANMAA MIKA, KOIVUKUNNAS, PEKKA, LAITILA, JYRKI, LUMPPIO, KARI, VALMET CORPORATION, VILJANMAA, MIKA
Application year: 1998
Main classification: D21G1
IPC codes: D21G1, F16C13