Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F3/00—Press section of machines for making continuous webs of paper
  • D21F3/02—Wet presses
  • D21F3/08—Pressure rolls
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
  • D21G1/00—Calenders; Smoothing apparatus
  • D21G1/02—Rolls; Their bearings
  • D21G1/0253—Heating or cooling the rolls; Regulating the temperature
  • D21G1/0266—Heating or cooling the rolls; Regulating the temperature using a heat-transfer fluid
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C13/00—Rolls, drums, discs, or the like; Bearings or mountings therefor

Definitions

• the present invention relates to a roll used in fiber web machines, preferably paper, board and chemical pulp machines, for processing, such as heating and/or cooling, a web-like material.
• the present invention relates to a fiber web machine roll for processing a fiber web, comprising a body having a first end and a second end; at least one shaft end fastened to the body and comprising at least one first flow channel for conducting a heat-transfer agent in and/or out; and a shell layer around the body for transferring heat from the heat-transfer agent to the fiber web/from the fiber web to the heat-transfer agent during operation.
• the present invention relates to a method in accordance with claim 18 for the roll maintenance of a fiber web machine roll in accordance with claim 1.
• the present invention relates to a method in accordance with claim 20 for manufacturing a fiber web machine roll.
• thermo rolls The thermal power necessary for calendering paper and board is currently produced by heated rolls, i.e., thermo rolls.
• Calender running speeds have risen significantly over the past few years.
• the surface temperatures of thermo rolls must be raised to 200 0 C - 250 0 C degrees.
• a high running speed combined with the high surface temperature of the thermo roll means that the thermal power exchange from the thermo roll must be very high, in new processes typically 200 kW/m or even higher.
• thermo roll As is well known, the heat of the thermo roll is produced by conducting a fluid serving as a heat-transfer agent in bores in its shell, in which the heat transfers to the shell and is conducted further to the surface of the roll.
• a fluid serving as a heat-transfer agent in bores in its shell, in which the heat transfers to the shell and is conducted further to the surface of the roll.
• Examples of arranging heat-transfer bores in peripheral bores in a shell are disclosed in publications such as DE 44 04 922 C1 and DE 40 36 121 A1.
• thermo roll Due to restrictions based on the manufacturing technology, heat-transfer agent bores must be located rather deep from the surface of the thermo roll, whereby the material remaining in between functions as an insulator and restricts the thermal power exchange from the thermo roll. Further, considering that the practical maximum temperature for the heat-transfer agent used in the thermo roll, i.e., oil, is about 300 degrees, the thermal power exchange from the thermo roll is limited to about 200 kW/min, and the surface temperature of the thermo roll is limited to 200 0 C degrees.
• thermo rolls While fiber web calendering and drying processes develop and machine lines are being renewed, old thermo rolls with too low a heat exchange must be replaced by new ones. Further use of such thermo rolls has not been arranged efficiently. It must be possible to modernize thermo rolls removed from service for renewed utilization.
• a general object of the present invention is to eliminate, or at least substantially alleviate, the disadvantages and weaknesses described above.
• a further object is to provide a fiber web machine roll that is capable of high heat transfer, whose flow channel system is simple to manufacture, that has low manufacturing costs, and whereby it can be ensured that the shell of the fiber web machine roll has the required characteristics, such as surface and strength characteristics, for example, and ensured that the body of the roll has the required characteristics, preferably load-carrying characteristics.
• a further object of the invention is to simplify the maintenance of fiber web machine rolls.
• a further object of the invention is to enable the manufacturing of a fiber web machine roll by using old roll bodies as a basis.
• a first method in accordance with the invention comprises replacing a metal shell forming a shell layer of a fiber web machine roll by another metal shell having the same characteristics or having different characteristics, which can preferably include at least one of the following: surface quality, hardness, thickness, material strength, suitability for welding, thermal conductivity, hardening capacity.
• a second method in accordance with the invention comprises using a body of a roll to be conditioned or that of a roll with peripheral bores as a basis for a body of a fiber web machine roll, in which second flow channels for conducting a heat-transfer agent from the inside of the body to its outer periphery are arranged.
• a tube-like metal shell with a wall thickness of about 1 to 20 mm is arranged as a shell layer around the body so that a peripheral flow chamber for a heat-transfer agent, having a height of about
• the roll comprises at least one flange fastened between the body and at least one shaft end, and the metal shell is fastened to the flange by welding at least at one of its border areas.
• a groove is formed on the surface of the body of the roll, a hoop is fastened with form closure to the groove, and the metal shell is fastened to the hoop by welding.
• a shoulder is formed on the surface of the body of the roll, a hoop comprising a groove is fastened to the shoulder with form closure, and the metal shell is fastened to the hoop by welding.
• the fiber web machine roll in accordance with the invention is intended for pressing and/or calendering and/or heating and/or cooling a fiber web in a contact, i.e., a nip, between the fiber web machine roll and a mating member contacting it, or for drying or heating or cooling the fiber web on the shell surface of the fiber web machine roll.
• the fiber web machine roll in accordance with the invention is suitable for use in one or more of the following applications of a fiber web machine: a thermo roll of a multiroll calender, a thermo roll of a soft calender, a thermo roll of a long-nip calender, a thermo roll of a shoe calender, a thermo roll of a belt calender, a thermo roll of a metal belt calender, a drying cylinder, a thermo roll of a press unit of a fiber web machine, and/or a thermo roll of a coating section of a fiber web machine.
• the body of the fiber web machine roll in accordance with the invention may be manufactured from a load-carrying, readily machined and inexpensive metal material, such as cast iron, which need not have particularly good heat-transfer characteristics, and the shell layer may be optimized in accordance with the characteristics required of a surface layer, such as good wear resistance and hardness.
• the shell layer may be formed to be relatively thin or very thin, whereby the consumption of the shell layer material is low.
• the shell layer may additionally be subjected to heat treatments, such as stress-relief annealing and/or hardening, and/or surface treatments and/or coatings to achieve the desired characteristics.
• Figure 1 shows a cross-section of a preferred thermo roll in accordance with the invention, equipped with a thin metal shell and a peripheral flow chamber for a heat-transfer agent, located within the shell.
• Figure 2 shows a partial enlargement of section A in Figure 1 , illustrating the fastening of the metal shell to a body of the thermo roll.
• Figure 3 shows a preferred design of the material inside a border area of the metal shell.
• Figure 4 shows the thermo roll in accordance with Figure 1 without the shell layer, and an example of a flow F of the heat-transfer agent in the peripheral flow chamber.
• Figures 5 to 8 show ways of fastening the metal shell of the thermo roll shown in Figure 1 , for example, in the axial direction in relation to the body.
• FIG. 1 shows a heated and/or cooled fiber web machine roll, i.e., a thermo roll 1 , for processing a fiber web.
• the thermo roll 1 comprises a body 2 for carrying a load, having a generally cylindrical outer surface, and shaft ends 3a, 3b, fastened to ends 2a, 2b of the body.
• the first shaft end 3a fastened to the first end 2a of the body 2 comprises at least one first flow channel 4a for conducting a heat-transfer agent in and/or out
• the second shaft end 3b fastened to the second end 2b of the body 2 comprises at least one first flow channel 4b for conducting the heat-transfer agent in and/or out.
• the thermo roll 1 comprises a shell layer 5 around the body 2 for transferring heat from the heat-transfer agent to the fiber web or from the fiber web to the heat-transfer agent during operation.
• the heat-transfer agent is preferably oil for use in high temperatures.
• a tube-like metal shell 5 with a wall thickness of about 1 to 20 mm, preferably 1 to 5 mm, is arranged as a shell layer around the body 2 of the thermo roll 1 so that a peripheral flow chamber 6 for the heat- transfer agent, having a height of about 1 to 2 mm in the radial direction of the preferably rotationally symmetrical thermo roll 1 , is formed between the body 2 and the metal shell 5.
• the fastening of the metal shell 5 to the body 2 of the thermo roll 1 in section A in Figure 1 is illustrated in more detail in Figure 2 and the related description, as well as in Figures 5 to 8 and the related description.
• the metal shell 5 may also be fastened to the shaft end 3a, 3b of the thermo roll 1 , as shown in Figure 7.
• the body 2 of the thermo roll 1 shown in Figure 1 is preferably cylindrical and tube-like, and comprises second flow channels 8a at its first end 2a, forming a flow connection between an internal first partial volume 7a at the first end 2a of the body 2 and the peripheral flow chamber 6 external to the body 2. Furthermore, the body 2 also comprises second flow channels 8b at its second end 2b, forming a flow connection between an internal second partial volume 7b at the second end 2b of the body 2 and the peripheral flow chamber 6 external to the body.
• the partial volumes 7a, 7b are formed in the body 2, the basic shape of which is preferably cylindrical and tube-like, by installing a separating wall 9a, 9b in each end area of the body, while the location of the separating walls may vary in the longitudinal direction of the body 2.
• the separating walls 9a, 9b enable separating from the internal volume of the body the partial volumes 7a, 7b, which are defined by a preferably cylindrical inner wall 2d of the body 2 and a wall 3a', 3b' of the shaft end 3a, 3b facing the body 2.
• the separating walls 9a, 9b are preferably positioned so that a large volume of the heat-transfer agent is not stored within the thermo roll 1.
• the partial volumes 7a, 7b at the different ends 2a, 2b of the body 2 need not be similar in terms of volume and dimensions; rather, they may be different from each other due to, e.g., differently arranged second flow channels 8a, 8b, different numbers of second flow channels 8a, 8b, or different kinds of shaft ends 3a, 3b fastened to the ends 2a, 2b of the body 2.
• the second flow channels 8a, 8b are preferably formed in the body 2 as radial bores.
• the positioning or number of the second flow channels 8a, 8b is not intended to be herein confined in any way. They may be arranged differently at the first end 2a of the body compared with the arrangement used at the other end 2b.
• a different number of second flow channels 8a, 8b may be located at the different ends 2a, 2b of the body 2, and/or the diameters of the second flow channels 8a, 8b may be different from those of adjacent second flow channels 8a, 8b or those of the second flow channels 8a, 8b at the other end 2a, 2b.
• Second flow channels 8a, 8b may be located at the same or different distances from one end 2a, 2b of the body, and/or at least one of the second flow channels 8a, 8b may be located at a different distance from one end 2a, 2b of the body, compared with several other second flow channels 8a, 8b that are mutually equidistant from this end of the body.
• the distances of the second flow channels 8a, 8b from each other in the body 2 are preferably arranged to be unequal in the direction of rotation of the periphery of the thermo roll 1.
• preferred numbers of such flow channels are the prime numbers 11 and 13.
• second flow channels 8a, 8b may also be manufactured in a thermo roll 1 by using a preferably cylindrical and tube-like body of a roll to be conditioned or that of a thermo roll with peripheral bores as a basis for a body 2, in which the second flow channels 8a, 8b for conducting a heat-transfer agent preferably from the inside of the body 2 to its outer periphery are arranged.
• a tube-like metal shell 5 with a wall thickness of about 1 to 20 mm is arranged as a shell layer around the body 2, so that a peripheral flow chamber 6 for the heat-transfer agent, having a height of about 1 to 2 mm in the radial direction of the thermo roll 1 , is formed between the body 2 and the metal shell 5.
• a flow channel system of the thermo roll 1 comprises the following in a flow connection in the manner shown in Figure 1 : a first flow channel 4a at a first shaft end 3a; a first partial volume 7a at a first end 2a of a body 2; second flow channels 8a connecting the first partial volume 7a and a peripheral flow chamber 6; the peripheral flow chamber 6; second flow channels 8b connecting the peripheral flow chamber 6 and a second partial volume 7b; the second partial volume 7b; and a second first flow channel 4b at a second shaft end 3b.
• the flow channel system of the thermo roll 1 may also comprise a solution where the conducting of the heat-transfer agent in and/or out is implemented through one shaft end, 3a or 3b.
• the flow may be implemented with a two-way coupling, i.e., flow in and flow out are implemented at the same shaft end by means of nested tubes, for example, whereby the return flow is conducted through the inner hole of the thermo roll back to the same end.
• the other shaft end may be implemented more simply, and/or other functions requiring space may be implemented at the other shaft end; for example, the rotation operation of the thermo roll may then be implemented via the other shaft end.
• the material of the metal shell 5 forming the shell layer of the thermo roll 1 is preferably welding steel, preferably structural steel.
• the material of the metal shell 5 is hardening alloyed steel.
• the material of the body 2 of the thermo roll 1 is cast iron, preferably ductile cast iron.
• Figure 2 shows a partial enlargement of section A in Figure 1 , illustrating the fastening of the metal shell 5 to the body 2 of the thermo roll 2 and the formation of the peripheral flow chamber 6 within the metal shell 5.
• the metal shell 5 is fastened by welding, preferably friction welding, to the body 2 at least at one of its border areas 5a, 5b - in Figure 2, at its border area 5a.
• the preferred area for welding 10 is indicated in Figure 2 by a dotted line.
• the metal shell 5 may be fastened to a shoulder 2c formed in the body 2.
• the metal shell 5 may also be fastened to the body 2 with a separate part (not shown) that is located around the body 2 and forms a preferably cylindrical shoulder, and, in this case, the body 2 has a preferably mainly cylindrical outer surface 2e, whereby less material has to be removed when forming the peripheral flow chamber.
• the height of the shoulder 2c determines the height of the peripheral flow chamber 6.
• the shoulder 2c may be formed, e.g., by machining the body 2 to be smaller than the diameter of the shoulder 2c in the desired area of the peripheral flow chamber 6.
• the metal shell 5 may be fastened around at least one shaft end 3a, 3b of the thermo roll 1.
• the fastening may be implemented by welding, as described in connection with Figure 2.
• the distance of the shoulder 2c to the edge of a nip during operation may be arranged to be large, and the fatigue load on the metal shell 5 remains lower.
• the shoulder 2c is preferably designed so as to minimize the fatigue load on the metal shell 5 and on the material used to form the shoulder. Therefore, the shoulder 2c is preferably designed as described above in the areas of both the shaft end 3a, 3b and the body 2, which is also illustrated in Figure 3 and the related description.
• the metal shell 5 may be fastened to the body 2 with a screw joint 11 in the area of the shoulder 2c described above at least at one of its border areas 5a, 5b, or, in another embodiment of the invention, at least at one shaft end 3a, 3b.
• the peripheral flow chamber 6 is arranged to endure a pressure of the heat-transfer agent equal to 2 to 3 bar.
• At least one seal 12 may preferably be used, which may be located at an end 2a, 2b of the body 2, or, in another embodiment of the invention, at a shaft end 3a, 3b, preferably in a groove 12 formed in the shoulder 2c against the assembled metal shell 5.
• Figure 3 shows a preferred design of the material 2a, 3a inside a border area 5a of the metal shell 5.
• the metal shell 5 is fastened around a shaft end 3a, which is designed so as to minimize the fatigue load on the metal shell 5 in border areas 5a, 5b.
• a joint provided around the shaft end 3a advantageously reduces, or even eliminates, the need for sealing the shaft end 3a in relation to the end 2a of the body 2. This construction also enables removing the metal shell 5 for maintenance without detaching the shaft ends 3a, 3b from the body 2.
• the following calculation example shows how to determine a length L of a rounded edge formed in the material inside the metal shell 5 in the longitudinal direction of the fiber web machine roll.
• the rounded edge includes two adjacent and interrelated rounding radii r forming the rounded shape of the shoulder 2c at the shaft end 3a, and the metal shell 5 is fastened around the roll end 3a, which, in turn, is fastened to the end 2a of the body 2.
• the height h of the peripheral flow chamber 6 is 2 mm
• the thickness t of the metal shell 5, made of steel is 10 mm.
• the bending stress at the rounded edge can be determined using formulas (I) and (II), where ⁇ is the fatigue load, and the modulus of elasticity E for steel is 210 GPa.
• t ⁇ — 2r (i)
• ⁇ E ⁇ (H)
• Figure 4 shows the thermo roll 1 shown in Figure 1 without the shell layer, and an example of a flow F of the heat-transfer agent in the area of the peripheral flow chamber 6 on an outer surface 2e of the body 2 of the thermo roll.
• the second flow channels 8a, 8b in the body 2 of the thermo roll 1 are preferably arranged outside the area where the fiber web contacts a surface 5c of the metal shell 5 during the operation of the thermo roll 1 , in order not to cause too high a temperature gradient in the fiber web being processed during the operation of the thermo roll.
• cavities such as grooves (not shown), can preferably be formed on the outer surface 2e of the body 2 to guide the flow in the peripheral flow chamber 6.
• the flow-guiding cavities may be in an axial direction on the roll 1 or at an oblique angle in relation to the axis of the roll, or spiral around the outer surface 2e of the body 2.
• the peripheral flow chamber 6 may be formed to be shallow, advantageously shallower than without the flow-guiding cavities, whereby the deformations of the metal shell 5 become small.
• thermo roll 1 may be a thermo roll of a calender, in which an outermost shell layer 5 that faces the paper, i.e., the metal shell 5, may be fastened on top of an inner body 5 with a shrink joint, for example.
• the shell layer 5 is subject to a large thermal load.
• the temperature difference between the shell layer 5 and the inner part of the thermo roll 1 , such as the heat-transfer agent, and/or the body 2 causes a temperature difference in the shell layer 5, which, in turn, causes movement of the shell layer 5 in the axial direction, particularly in the end areas 5a, 5b of the shell layer 5.
• the movement of the shell layer 5 in the axial direction must be prevented in order for said shrink joint to function as required and to avoid the fatigue phenomenon called fretting, among other things.
• fretting the fatigue phenomenon
• the problem occurs when the core material of the body 2 of the thermo roll 1 and the material of the shell layer 5 are different, and thus difficult to joint together by welding, for example. Movement in the axial direction must be prevented in both directions at both end areas 5a, 5b of the shell layer 5.
• the fastening of the metal shell 5 shown in each of Figures 5, 6, 7 and 8 may also comprise a sealing structure 12 as described in connection with Figure 2.
• the metal shell 5 is fastened to a groove 13 formed in the body 2 of the thermo roll by means of a hoop 14 at least at one of its border areas 5a, 5b - in Figure 5, at the border area 5a.
• This kind of a fastening method enables detaching the shaft ends 3a, 3b from the body 2 while the metal shell 5 remains in place.
• screws 11 of large dimensions are not needed, as the joint with form closure between the groove 13 and the hoop 14 mainly carries the load applied to the joint in the axial direction.
• a welding joint 16a can be machined between the hoop 14 and the metal shell 5.
• the hoop 14 can be regarded as an inexpensive and replaceable joint piece, which can easily be replaced by a new one.
• the body 5 need not be eroded by said machining, and the erosion or shortening of the metal shell 5 in the axial direction is slight.
• the groove 13 where the hoop 14 is fastened is formed on the body 2 of the thermo roll 1 , preferably on the surface of the body 2 in the end area 2a of the body.
• the hoop 14 is of a welding material, preferably steel.
• the border 5a of the metal shell 5 is fastened to the hoop 14 by welding.
• the welded seam is indicated as 16a.
• the cross-sectional shapes of the groove 13 and the hoop 14 are preferably wedge-like, preferably corresponding to each other.
• the sides of the hoop 14 communicate the axial force via the sides of the groove 13 to the body 2 in order to keep the metal shell 5 in place in the axial direction in relation to the body 2.
• the hoop 14 is preferably installed in a cut state in the groove 13, and the ends of the cut hoop parts are, e.g., welded together.
• the hoop 14 may also be divided in two in the axial direction of the thermo roll 1 , for example, which is illustrated by reference 15.
• the border 5a of the metal shell 5 is fastened to a first hoop 14 by welding, and a second hoop 15, which is fastened by screws 11 , can be used to achieve the final fastening by tightening the hoop 14, 15 in the groove 13.
• a groove on the body 2 may also be replaced by a shoulder (not shown) on the body, and, correspondingly, a groove that fits said shoulder may be arranged in the hoop, whereby the sides of the groove in the hoop communicate the axial force via the sides of the shoulder to the body 2 in order to keep the metal shell 5 in place in the axial direction in relation to the body 2.
• Figure 6 shows an alternative way of fastening the metal shell 5 to the body 2 of the thermo roll 1.
• the metal shell 5 is fastened to the body 2 at its border area 5a with a screw joint 11 in the radial direction of the thermo roll 1 , without a welded joint.
• a screw joint requires using screws 11 of large dimensions and fitting these screws 11 to an end area of the thermo roll 1 together with fastening screws 17 of the shaft end 3a, 3b.
• Figure 7 shows an alternative way of fastening the metal shell 5 to at least one shaft end 3a, 3b of the thermo roll 1.
• the metal shell 5 is fastened to the shaft end 3a, 3b at the edge of the end area 5a by welding.
• the welded seam is indicated as 16b.
• the metal shell 5 can be fastened to the shaft end 3a with a screw joint 11 ' in the axial direction, in which case the shell layer is required to be thick enough for the screw joint 11 '.
• thermo roll 1 shown in Figure 8 comprises at least one flange 18, which is fastened between the body 2 and at least one shaft end 3a, 3b, and the metal shell 5 is fastened to the flange 18 at least at one of its border areas 5a, 5b.
• the welded seam is indicated as 16b.
• thermo roll in accordance with the invention is preferably at least one of the following: a thermo roll of a multiroll calender, a thermo roll of a soft calender, a thermo roll of a long-nip calender, a thermo roll of a shoe calender, a thermo roll of a belt calender, a thermo roll of a metal belt calender, a drying cylinder, a thermo roll of a press unit of a fiber web machine and/or a thermo roll of a coating section of a fiber web machine.
• a method in accordance with the invention for roll maintenance of a thermo roll 1 comprises replacing a metal shell 5 forming a shell layer by another metal shell 5 that has materially the same characteristics as, or characteristics different from, the metal shell 5 to be replaced.
• the metal shell 5 of the thermo roll 1 to be replaced is different in terms of at least one of the following characteristics: surface quality, hardness, thickness, material strength, suitability for welding, thermal conductivity, hardening capacity.
• a method for manufacturing a heated and/or cooled roll i.e., a thermo roll 1 , comprising a body 2 for carrying a load, having a first end 2a and a second end 2b; at least one shaft end 3a, 3b, fastened to an end 2a, 2b of the body 2 and comprising at least one first flow channel 4a, 4b for conducting a heat-transfer agent in and/or out; and a shell layer around the body 2 for transferring heat from a heat-transfer agent to a fiber web or from the fiber web to the heat-transfer agent during operation; comprises using a body of a roll to be conditioned or that of a thermo roll with peripheral bores as a basis for the body 2 of the thermo roll, in which second flow channels 8a, 8b are arranged for conducting the heat-transfer agent from the inside of the body 2 to its outer periphery; arranging a tube- like metal shell 5 with a wall thickness of about 1 to 20 mm as a shell layer around the body 2 so that
• thermo roll relating to the invention does not include separate "peripheral bores" for the heat-transfer agent in the body of the roll, or such separate bores need not be used for conducting the heat-transfer agent; instead, the roll is mainly divided into two parts, the body 2 and the metal shell 5 with relatively thin walls.
• the heat-transfer agent is conducted as a flow F through the second flow channels 8a, 8b in the body 2 to an outer surface 2e of the body 2 and along this surface and, optionally, also along flow cavities formed on the surface, and the flow chamber 6 thereby formed is closed with the metal shell 5 installed on the body 2.
• the metal shell 5 is preferably very thin, whereby the insulating layer between the surface of the thermo roll 1 and the heat-transfer agent remains thin, only having a thickness of 1 to 2 mm.
• the body 2 of the thermo roll 1 carries the external load applied to the roll, such as the nip pressure in a calender, for example.
• the metal shell 5 is pressed against the body 2 in the nip of a calender or a press unit.
• the heat-transfer agent additionally functions as a lubricant between the metal shell 5 and the body 2, and reduces the friction and wear generated in the contact between the metal shell and the body, caused by nip contact, for example.
• lubrication characteristics may be improved by using additives in the oil.
• thermo roll 1 By means of the thermo roll 1 in accordance with the invention, a nip profiling effect can be provided when a magnetorheological oil is used as the heat-transfer agent and a magnet is applied to the oil.
• a nip profiling effect can be achieved by controlling the magnet(s) in a suitable manner and by positioning the magnet in a suitable way.
• the location of the magnetorheological heat-transfer agent in the area of the peripheral flow chamber 6 can be influenced, and the velocity and rate of flow of the magnetorheological heat-transfer agent can be controlled by arranging the location and strength of the magnetic flux to guide the heat-transfer agent in the area where nip profiling is desired.
• a higher temperature can be achieved by accelerating the flow of the heat-transfer agent and/or by increasing the rate of flow of the hot heat-transfer agent.
• thermo rolls such as the thermo roll 1 in accordance with the invention and known thermo rolls with peripheral bores
• a heat-transfer agent preferably including hot, glowing tin, sodium or mercury particles into the heat-transfer channel system of the thermo roll, and conduct the fluid containing the particles out of the heat-transfer channel system after the heat has been released.
• particles such as tin, sodium or mercury particles, can preferably be heated by means of induction, for example.
• the metal shell 5 can be provided with perforations for the steam. Hot steam may then be introduced at high pressure into the heat-transfer channel system and blown out from the peripheral flow chamber 6 through the perforated metal shell 5.
• thermo rolls generally, as well as in the thermo roll 1 in accordance with the invention, may be enhanced by equipping the thermo roll 1 with an internal circulation pump for the heat-transfer agent.
• the aim is to achieve a high rate and velocity of flow in the thermo roll 1 , whereby the heat transfer is more efficient.
• the circulation pump enables accelerating the flow of the heat-transfer agent, whereby pressure losses in the heat-transfer channel system of the thermo roll and heat-transfer agent piping preceding the thermo roll do not restrict the flow of the heat- transfer agent, and the flow of the heat-transfer agent can be brought to a level that would be reached without flow resistance in the flow piping and the flow channels of the heat-transfer agent.
• the circulation pump can be arranged at an end of the thermo roll 1 , in connection with an oil coupling or a roll end 3a, 3b, for example, in which case the circulation pump may obtain its driving power from the rotation of the thermo roll.
• any form defects of a generally cylindrical and tube-like thermo roll, as well as those of the thermo roll 1 can be compensated by internal heating/cooling within the body 2 of the thermo roll 1.
• An example of such a form defect to be compensated is a form defect where thermal loss takes place via a shaft end 3a, 3b towards the surrounding structures of the fiber web machine and the diameter of the shell of the thermo roll is smaller than desired.
• excess heat enters the area of the shell of the thermo roll 1 via, e.g., a shaft end 3a, 3b and the diameter of the shell of the thermo roll is larger than desired.
• thermo roll a preferably friction-based "brake shoe” type of heating can be arranged inside the body of the thermo roll, e.g., in the area of the end(s) 2a, 2b of the body 2, whereby compensating heat is generated by pressing a friction piece or pieces against, e.g., a cylindrical inner surface of the body, and the outer diameter of the shell can be caused to increase. It is also possible to implement similar additional heating in connection with an end of a thermo roll with an electric resistor.
• thermo roll 1 enables achieving surface temperatures as high as close to 300 degrees and, thanks to a lubricating film beneath the metal shell 5, also enables using longer nip lengths than when using a conventional thermo roll with a hard surface.
• the thermo roll 1 may be implemented by modernizing old thermo rolls, particularly their bodies, to become in accordance with the invention. Roll maintenance can also be performed by replacing a worn metal shell by a new shell.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Paper (AREA)
• Rolls And Other Rotary Bodies (AREA)
• Nonwoven Fabrics (AREA)
• Treatment Of Fiber Materials (AREA)
• Reduction Rolling/Reduction Stand/Operation Of Reduction Machine (AREA)

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• 2007
  • 2007-12-03 FI FI20075869A patent/FI20075869A7/sv not_active IP Right Cessation
• 2008
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  • 2008-11-26 DE DE112008002895T patent/DE112008002895T5/de not_active Withdrawn
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  • 2008-11-26 WO PCT/FI2008/050685 patent/WO2009071739A1/en not_active Ceased

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