Thermo roll for paper or carboard machine

Abstract

A thermo roll (1) for a paper and / or a cardboard machine, wherein the thermo roll (1) comprises: a hollow roll body (2) comprising at least one open channel (3) on a surface layer (4); and a ceiling (5) on the at least one open channel (3) configured to close the at least one open channel (3) and to form at least one closed channel (6) on the surface layer (4) of the roll body (2) for heat transfer medium. Also a method is disclosed.

Description

[0001] THERMO ROLL FOR PAPER OR CARBOARD MACHINE

[0002] FIELD OF THE INVENTION

[0003] The present application relates generally to a thermo roll . More specifically, the present application relates to the thermo rol l for a paper or carboard machine .

[0004] BACKGROUND OF THE INVENTION

[0005] Thermo rolls are heated rolls in a paper or cardboard machine , which may have axial channels in a sleeve of the roll for cooling or heating purposes . Hot water, steam or oil may pass through the channels to heat a roll surface that is in contact with a web to the desired temperature . Manufacturing and drilling of axial holes to the sleeve of the roll may be difficult and challenging . Therefore , manufacturing methods of the thermo rolls may be further improved .

[0006] SUMMARY

[0007] This summary is provided to introduce a selection of concepts in a s implif ied form that are further described below in the detailed description . This summary is not intended to identify key features or essential features of the claimed subj ect matter, nor is it intended to be used to limit the scope of the claimed subj ect matter . The scope of protection sought for various embodiments of the present disclosure is set out by the independent claims .

[0008] The embodiments of the present disclosure provide a thermo roll for a paper or a carboard machine and a method for forming a thermo roll for a paper or a carboard machine . The manufacturing method of channels may be changed from dril ling to friction channeling by surfacing . The friction channeling by surfacing may produce sub-surface channels , along a free path, on a surface layer of the thermo roll . A friction channeling by surfacing process may leave the channels ideal for heat transfer, as it may create rough surfaces that may have a higher surface area and may help to have turbulent flow that may increase the heat transfer . Further, the friction channeling by surfacing may allow using a larger number of smaller channels in comparison to drilling . This may lead to a more uniform thermal profile .

[0009] According to a f irst aspect a thermo roll for a paper and / or a carboard machine is disclosed . The thermo roll may comprise : a hollow roll body, which may comprise at least one open channel on a surface layer ; and a ceiling on the at least one open channel , which may be configured to close the at least one open channel and to form at least one closed channel on the surface layer of the roll body for heat transfer medium .

[0010] Friction channeling by surfacing may allow use of a larger number of smaller channels in comparison to drilling, which may lead to more uniform thermal profile . The benefits for a manufacturer and user of the thermo rolls are that they may get a thermo roll that may have better running characteristics , including higher maximum operating speed, lower vibration, and more uniform temperature profile . These may contribute to lower running costs due to reduced maintenance needs and may increase life of the thermo rolls due to more uniform temperature operation and lower thermal fatigue and induced cracking . The benefit for the manufacturer may be that a tedious and error-prone drilling proces s may become redundant . The channels may also be closer to the surface of the thermo roll body, thus heating may be more effective .

[0011] According to an embodiment of the first aspect , the closed channels may be configured made by a friction channeling by surfacing method . According to an embodiment of the first aspect , a longitudinal shape of the at least one open channel or the at least one closed channel along a channel path may be one of the following or any combination of the following : arbitrary, constant , variable , continuously variable , and / or a combination of constant and variable zones . The channels may be ideal for heat transfer because they may have different forms along the channel path creating turbulent flow that may increases the heat transfer .

[0012] According to an embodiment of the first aspect , a cross-sectional shape of the at least one open channel may be one of the following or any combination of the following : rectangular, conical , inverse conical , triangular, parallelogram, quadrangular, circular, and / or partially circular . Parameters of the channeling by surfacing process , form of the open channel , and material properties may affect achieved roughness , shape , and thickness of the ceiling . Form of the channel may be freely chosen . The cross section of the open channel may be easily made and for example , rectangular or trapezoidal cross sections may have better heat transfer than a circular cross section due to the surface area per unit length . Other shapes may also be possible , but may be limited by a machining method of the open channel or a groove .

[0013] According to an embodiment of the first aspect , a shape of at least one upper edge of the at least one open channel may be one of the fol lowing or any combination of the following : arbitrary, right angle, sharp, inclined, chamfered, circular, inverse circular, curved, and / or rectangularly formed boundary . Form of the upper edges of the open channel may define how a consumable tool may be forged against the upper edges and thus how the ceiling material may be formed .

[0014] According to an embodiment of the first aspect , a channel width between the upper edges of the open channel may be constant , variable , continuously variable , or a combination of constant and variable along the channel path . Different channel forms may be used to create more turbulent flow of the heat transfer medium, which may increase the heat transfer .

[0015] According to an embodiment of the first aspect , the at least one open channel may be configured to be formed on the surface layer of the thermo roll along the at least one of the following channel path or any combination of the following channel paths : a straight path, a free path, and / or helical path . A hel icoid arrangement of at least one channel path may be used to reduce excitations from varying temperature and stiffness of the thermo roll surface compared to straight channel paths . Further traj ectories of the at least one channel path, such as wavy, curved, and variations including combinations of the previously mentioned or other freeform traj ectories may be used to optimi ze performance of the thermo roll .

[0016] According to an embodiment of the first aspect , the free path may be configured to be formed along one or more linear or curved segments , or any combination of one or more linear and curved segments . Linear, curved, and variations including combinations of the previously mentioned or other freeform traj ectories of the channel path may be used to optimi ze the performance of the thermo roll .

[0017] According to an embodiment of the first aspect , at least two open channels may be configured to be kept separated or crossing their channel paths . The channels may be arranged obliquely or in the form of a spiral , for example , in order to advantageously avoid clogging or barring . The channels may have varying distances from each other . The channels may also be arranged to meet with other flow channels obliquely crosswise or to meet with other flow channels in a spiral form to provide suitable turbulence, i.e., enhancement of the flow in a flow channel system for the heat transfer medium.

[0018] According to an embodiment of the first aspect, the at least two open channels may be configured to be located at least partly at the same depth from top surface or at least partly at different depths from a top surface of the thermo roll. The channeling by surfacing method may allow optimization of the channel location from the top surface for more even temperature profile of the thermo roll than a conventional drilling method.

[0019] According to an embodiment of the first aspect, a ceiling shape may be at least one of the following: arbitrary, inclined, trapezoid, concave, and / or saddle- like. The parameters of the channeling by surfacing process and the material properties may affect achieved roughness, shape, and thickness of the ceiling. Unevenness of the ceiling may improve thermal transfer.

[0020] According to a second aspect a method for forming a thermo roll for a paper and / or a carboard machine is disclosed. The thermo roll may comprise a hollow roll body, wherein the method may comprise forming at least one open channel on a surface layer of the roll body; and forming a ceiling on the at least one open channel; wherein the ceiling may close the at least one open channel and may form at least one closed channel on the surface layer of the roll body for heat transfer medium. The method may allow optimization of the trajectory of the channels. For example, a helicoid arrangement may be used to reduce excitations from varying temperature and stiffness of the thermo roll top surface compared to straight channels. Further trajectories or channel paths, such as wavy, curved, and variations including combinations of the previously mentioned or other freeform trajectories may be used to optimize the performance of the thermo roll. The channeling by surfacing methods may allow optimization of the channel shape, trajectory and size for more even temperature profile of the thermo roll than the conventional drilling method .

[0021] According to an embodiment of the second aspect , the at least one open channel may be formed by machining . Conventional machining methods may be used when the open channel is formed . Expensive and special equipment may not be needed .

[0022] According to an embodiment of the second aspect , a consumable tool may be used to form the ceiling of the at least one closed channel . When using the consumable tool there may be no melting of the consumable tool , only severe plastic deformation by thermomechanical processing .

[0023] According to an embodiment of the second aspect , the consumable tool may be rotatable . When the consumable tool is forged against the upper edges of the open channel and rotated it may cause severe plastic deformation by the thermomechanical processing to form the ceiling material . Rotating may improve plastic deformation .

[0024] According to an embodiment of the second aspect , the consumable tool may be configured to travel along a channel path of the at least one open channel , wherein the consumable tool may be forced against upper edges of the at least one open channel to deposit material from the consumable tool at least on top of the at least one open channel to form the ceiling of the at least one closed channel . When the consumable tool is forged against the upper edges of the open channel it may cause severe plastic deformation by the thermomechanical processing to form the ceiling material . Also , when using the consumable tool , welding may not be needed . Welding may affect thermal properties of the welded material and heat treatment may be needed afterwards . Welding may increase deformations and heat deflection of the thermo rol l . When us ing the consumable tool deformations of the thermo roll may be reduced . According to an embodiment of the second aspect , wherein forcing a consumable tool against the upper edges of the at least one open channel may mix the tool material with surface layer material via plastic deformation and may create the ceiling . This may make the ceiling durable .

[0025] According to an embodiment of the second aspect , during or after the ceiling is formed a top surface of the roll body may undergo a finishing operation . In the final step, the surface of the roll body may be machined to a desired geometry, because the top surface may be rough from the channeling operation .

[0026] According to a third aspect a use of a thermo roll according to any one of the first aspects for heating and / or cooling .

[0027] BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings , which are included to provide a further understanding of the invention and constitute a part of this specification, illustrate embodiments of the invention and together with the description help to explain the principles of the invention . In the drawings :

[0029] Figure la shows schematically an example of a thermo roll according to an embodiment ;

[0030] Figure lb shows schematically an example of a cross-section of the thermo roll of figure la according to an embodiment ;

[0031] Figure 1c shows schematically another example of a thermo roll according to an embodiment ;

[0032] Figures 2a-2h show schematically examples of friction channelling by surfacing process phases according to an embodiment ;

[0033] Figures 3a-3g show schematically other examples of friction channelling by surfacing process phases according to an embodiment ; Figures 4a and 4b show schematically examples of closed channels formed on a surface layer of the thermo roll according to an embodiment ;

[0034] Figures 4c-4e show schematically examples of ceiling shapes of the closed channels of the figures 4a and 4b according to an embodiment ;

[0035] Figures 5a-5e show schematically examples of cross-section shapes of open channel s formed on a surface layer of the thermo roll according to an embodiment ;

[0036] Figures 6a- 6e show schematically examples of top edge shapes of open channels according to an embodiment ; and

[0037] Figure 7 shows an example method for forming a thermo roll according to an embodiment .

[0038] Like references are used to designate like parts in the accompanying drawings .

[0039] DETAILED DESCRIPTION

[0040] Reference will now be made in detail to embodiments , examples of which are illustrated in the accompanying drawings . The detailed description provided below in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present example may be constructed or utili zed . The description sets forth the functions of the example and the sequence of steps or operations for constructing and operating the example . However, the same or equivalent functions and sequences may be accomplished by different examples .

[0041] According to an example embodiment , thermo rolls are rolls and cylinder-like machine elements , for example paper and / or cardboard machine thermo rolls . The thermo rolls may be heated rolls in the paper and / or cardboard machine , which may have axial channels in a sleeve of the roll for cooling or heating purposes . Hot water , steam or oil may be pas sed through the channel s to heat the roll surface that is in contact with the web to the desired temperature . Manufacturing and drilling of axial holes to the s leeve of the thermo roll may be difficult and challenging . These axial holes may be gun drilled from both ends of the thermo roll so that the holes meet in the center of the thermo roll . The drilling process may be problematic due to a large depth-to- diameter ratio of the hole . Due to flexibility of the drill , variable hardness of the material , other material defects , and even j ust the effect of gravity on the drill , some or all of these reasons may be enough to divert the drill enough to make some error in the placement of the hole along the length of the thermo roll . The manufacturing errors may lead to non-uniform thermal profile of the roll . Non-uniform thermal expansion of the roll may be problematic, as it may create vibration and bending problems , and may limit the running speed of the thermo roll .

[0042] According to an example embodiment, a manufacturing method of the channels or holes are changed from drilling to friction channeling by surfacing . This method with sub-surface channels may enable more efficient and tailor-made designs for thermal management of the thermo rolls . The friction channeling by surfacing may produce sub-surface channels , along a free path, on a surface layer of the thermo roll . In the friction channeling by surfacing at least one open channel may be machined first , for example via milling operation . Then a ceiling may be added to the initial at least one open channel , which may form the final at least one closed sub-surface channel . The implementation of the consecutive manufacturing phases of the friction channeling by surfacing may be done with, or without , any time interval .

[0043] A cross-sectional shape of the open channel may be at least one of the following or any combination of the following : rectangular, conical , inverse conical , triangular, parallelogram, quadrangular, circular, and / or partially circular . The longitudinal shape of the open channel from the first step may be constant or variable along the path . The channel width between the edges of the open channel may be constant or variable along the path . The shape of the edges of the open channel may be at least one of the following or any combination of the following : arbitrary, right angle , sharp, inclined, chamfered, circular, inverse circular, curved, and / or rectangularly formed boundary .

[0044] The ceiling may be j oined to the thermo roll component in a solid state domain, providing a fully functional and leak free closed sub-surface channel . During the friction channeling by surfacing a consumable tool may travel along the open channel path to produce the final closed sub-surface channel . The consumable tool may be a rotating consumable tool . The consumable tool may be deposited over the formed open channel . The consumable tool is , for example a rod . The consumable tool may be forged against the edges of the open channel . This may plastically deform the top edges of the open channel and the tool , which may undergo viscoplastic deformation with the inherent generation of heat . This may be because of plastic work dissipation and friction energy dissipation at the contacting rubbing interfaces between the components . The plastic deformation of both the consumable tool and the edges of the open channel may create new chemically active surfaces , that under contact pressure and temperature may activate diffusion j oining mechanisms that may provide load bearing resistant j oin of the consumable tool with the original thermo roll material . It may also contribute to the progressive transference of the processed layer of the consumable tool into the ceiling of the open channel , which may form the ceil ing and generate the functional closed sub-surface channel . The channel path of the consecutive manufacturing phases of the friction channeling by surfacing may be the same . A free channel path of the sub-surface open or closed channel may mean that it may be made along linear or curved segments or any combination of these segments . One or more continuous sub-surface channels may be manufactured on the surface layer of the thermo roll . Along the free channel path of the subsurface channel , the sub-surface channels may be kept separated or coming together, for example , crossing their paths . The sub-surface channels may be produced at the same depth from the top surface or at dif ferent depths . Overlapping sub-surface channels , produced at different depths from the top surface of the thermo rolls may also be pos sible . After the ceiling has been added on the open channel with the friction channeling by surfacing, the outer surface or the top surface of the processed zone may undergo a finishing operation . According to an example embodiment , the finishing operation may be simultaneous or sequential with the surface finish operation of the thermo roll .

[0045] An example of figure la shows schematically a thermo roll 1 . It comprises channels 6 , which may be formed by friction channeling by surfacing along the thermo roll 1 . An example of figure lb shows schematically a cross-section of the thermo roll 1 of figure la .

[0046] According to an example embodiment, the thermo roll 1 for a paper and / or a carboard machine may comprise a hollow roll body 2 comprising at least one open channel 3 on a surface layer 4 . Further the thermo roll may comprise a ceiling 5 on the at least one open channel 3 configured to close the at least one open channel 3 and to form at least one closed channel 6 on the surface layer 4 of the roll body 2 for heat transfer medium . The heat transfer medium is , for example water, steam, or oil . In the example of figure la, the channels 6 are located axially and in paral lel on the surface layer 4 of the roll body 2 . The channels 6 may be located at the same distance from the top surface 9 and they may not intersect each other . The channels 6 may also be located at the same or varying distance from each other .

[0047] An example of figure 1c schematically shows a thermo roll 1 . It comprises helicoid-like channels 6 , which may be formed by the friction channeling by surfacing along the thermo roll 1 .

[0048] In the example of figure 1c the closed channels 6 are located helically on the surface layer 4 of the roll body 2 . The helically located channels 6 may be located in a mesh- or grid-like formation . The channels 6 may be located at a same distance from a top surface 9 , in which case they may intersect each other . The channel s 6 may be located at a different distance from the top surface 9 , in which case they may not intersect each other .

[0049] According to an example embodiment , a longitudinal shape of the at least one open channel 3 or the at least one closed channel 6 along a channel path 10 is one of the following or any combination of the fol lowing : arbitrary, constant , variable , continuously variable , and / or a combination of constant and variable zones .

[0050] According to an example embodiment , the at least one open channel may be configured to be formed on the surface layer 4 of the thermo roll 1 along the at least one of the following channel paths 10 or any combination of the following channel paths 10 : a straight path, a free path, and / or helical path .

[0051] According to an example embodiment , the free path is configured to be formed along one or more linear or curved segments , or any combination of one or more linear and curved segments . According to an example embodiment , at least two open channels 3 are configured to be kept separated or crossing their channel paths 10 .

[0052] According to an example embodiment , the at least two open channels 3 are configured to be located at least partly at the same depth from top surface 9 or at least partly at different depths from the top surface 9 of the thermo roll 2 .

[0053] Examples of figures 2a-2h show schematically friction channelling by surfacing process phases . The open channel 6 may be machined into a workpiece , for example into a part of the roll body 2 . The example of figure 2a shows the initial situation with the part of the rol l body 2 . The example of figure 2b shows how an open channel 3 has been machined into the rol l body 2 . The example of figure 2c shows the approach of a rotating consumable tool 7 to the roll body 2 . The example of figure 2d shows the commencement of the channeling by surfacing process with the initial thermomechanical deformation of the consumable tool 7 . The example of figure 2e shows progressing of the channeling process along a direct part of the machined open channel 3 and ceiling 5 of the closed channel 6 created by deposition of consumed volume of the consumable tool 7 . The example of figure 2 f shows progressing of the channeling by surfacing process along a curved part of the machined open channel 3 . The example of figure 2g shows progressing of the channeling by surfacing process towards an end of the machined open channel 3 . The example of figure 2h shows the ready-made closed channel 6 inside the rol l body 2 when the consumable tool 7 has been removed from the roll body 2 . The closed channel 6 may be covered by the deposited ceiling 5 . As can be seen from the example of figure 2h the consumable tool 7 has been almost worn out in the channeling by surfacing process .

[0054] Examples of figures 3a-3g show schematically the friction channelling by surfacing process phases . The example of figure 3a presents a consumable tool 7 , its simultaneous rotation according to arrow P and approach to the surface layer 4 . The consumable tool 7 may be rotated clockwise or counterclockwise . The example of figure 3b shows how the consumable tool 7 is lowered down according to an arrow D onto a top surface 9 of the roll body 2 and how it is contacting with the top surface 9 . The example of figure 3c shows deposition via thermomechanical deformation of a consumed volume of the rotating consumable tool 7 creating a ceiling 5 of a closed channel 6 on the roll body 2 . The examples of figures 3d and 3e present further the friction channeling by surfacing process and continuation of deposition, along the traj ectory of a channel path 10 , of the consumed volume of the consumable tool 7 over the open channel 3 and creating the ceiling 5 . An arrow M shows the direction of the movement along the channel path 10 . The example of figure 3 f shows how the consumable tool 7 reaches an end of the open channel 3 . The example of figure 3g presents termination of the friction channeling by surfacing process and lifting of the rotating consumable tool 7 away from the roll body 2 . In the example figure 3g the machined open channel 3 is now completely covered by the deposited ceiling 5 and the closed channel 6 is formed .

[0055] Figures 4a and 4b show schematically examples of closed channels 6 formed inside a surface layer 4 of the thermo roll 2 by a surfacing process . Figures 4c-4e show schematically examples of various ceiling shapes 11 inside the closed channels 6 of the Figures 4a and 4b . The example of figure 4c shows an arbitrary ceiling shape 11 . The example of figure 4d shows inclined or trapezoid ceiling shape 11 . The example of figure 4e shows concave or saddle-like ceiling shape 11 .

[0056] According to an example embodiment , a ceiling shape 11 of the at least one closed channel 6 is at least one of the following : arbitrary, inclined, trapezoid, concave , and / or saddle-like . The ceiling shape 11 may be inside the at least one closed channel 6 .

[0057] Figures 5a-5e show schematically examples of cross-section shapes of open channels 3 formed on a surface layer 4 of the thermo roll 2 by the friction channeling by surfacing process . The example of figure 5a presents a rectangular cross-section shape , which has a channel width Wchand a channel height Hch. The example of figure 5b shows a conical cross-section shape . An angle between opposite sides may be a . The example of figure 5c shows an inverse conical cross-section shape . An angle between opposite sides may be [3 . The example of figure 5d shows a parallelogram cross-section shape . An angle between one of the sides and a vertical axis may be 5 . The example of figure 5e shows a circular or a partially circular cross-section shape having a radius R .

[0058] According to an example embodiment , a cross- sectional shape of the at least one open channel 3 or at least one closed channel 6 is one of the following or any combination of the following : rectangular, conical , inverse conical , parallelogram, quadrangular, circular, and / or partially circular .

[0059] Figures 6a- 6e show schematically examples of upper edge shapes of open channels 3 . The example of figure 6a shows a right or a sharp angle shape of an upper edge 8 . The example of figure 6b presents an inclined shape of an upper edge 8 . An angle between an inclined side of the upper edge 8 and a vertical axis may be s . The example of figure 6c shows a circular shape of an upper edge 8 with a radius R . The example of figure 6d shows an inverse circular shape of an upper edge 8 with a radius R . The example of f igure 6e shows a rectangularly formed boundary of an upper edge 8 , wherein Hsand Wsare height and width dimensions of a rectangle . According to an example embodiment , a shape of at least one upper edge 8 of the at least one open channel 3 is one of the following or any combination of the following : arbitrary, right angle , sharp, inclined, chamfered, circular, inverse circular, curved, and / or rectangularly formed boundary .

[0060] According to an example embodiment , a channel width Wchbetween upper edges 8 of the open channel 3 is constant , variable , continuously variable , or combination of constant and variable along the channel path 10 .

[0061] According to an example embodiment friction channeling by surfacing is a method to form channels in a roll body 2 . In the beginning of the method, open grooves or open channels 3 may be machined into the roll body 2 along the desired channel traj ectories or channel paths 10 , for example , with conventional machining methods .

[0062] After machining, a consumable tool 7 may be forced against the roll body 2 . This may deposit material of the consumable tool 7 on top of the open groove or channel 3 and may form a ceiling 5 on the open channel 3 . The mixing of the consumable tool material may happen in a solid state , which may reduce residual stresses in the roll body 2 . The mixing of the tool material to roll body material may leave a rough surface , which is desirable . For example , when using the rough surface in thermal management in closed channels 6 , the turbulent flow induced by the unevenness of the closed flow channel 6 may improve the thermal transfer . Parameters of the channeling by surfacing process and material properties may affect the achieved roughness , shape , and thickness of the ceiling 5 . The cross section of the open channel 3 may be eas ily made . For example , a rectangular or trapezoidal cross section may have better heat transfer than a circular dril led hole due to the surface area per unit length . Other shapes may also be possible . However, they may be limited by the machining method of the groove or open channel 3 .

[0063] Finally, the surface of the roll body 2 may be machined to a desired geometry, as the top surface 9 may be rough from the channeling . For manufacturing of the thermo rolls 1 , the outside surface of the thermo roll 1 may be turned and / or ground to the final shape of the roll body 2 .

[0064] Figure 7 illustrates an example of a method for forming a thermo roll 1 for a paper or a carboard machine , wherein the thermo rol l 1 comprises a hollow rol l body 2 .

[0065] At operation 700 , the method may comprise forming at least one open channel 3 on a surface layer 4 of the roll body 2 .

[0066] At operation 710 , the method may comprise forming a ceiling 5 on the at least one open channel 4 .

[0067] At operation 720 , the method may comprise that the ceiling 5 is closing the at least one open channel 3 and forming at least one closed channel 6 on the surface layer 4 of the roll body 2 for heat transfer medium .

[0068] According to an example embodiment , the at least one open channel 3 is formed by machining .

[0069] According to an example embodiment , the consumable tool 7 is used to form the ceiling 5 of the at least one closed channel 6 .

[0070] According to an example embodiment , the consumable tool 7 is rotatable .

[0071] According to an example embodiment , the consumable tool 7 is configured to travel along a channel path 10 of the at least one open channel 3 , wherein the consumable tool 7 is forced against upper edges 8 of the at least one open channel 3 to deposit material from the consumable tool 7 at least on top of the at least one open channel 3 to form the ceiling 5 of the at least one closed channel 6 . Further features of the method directly result from functionalities of , for example , the thermo roll . Different variations of the method may be also applied, as described in connection with the various embodiments .

[0072] Any range or device value given herein may be extended or altered without losing the effect sought . Also , any embodiment may be combined with another embodiment unless explicitly disallowed .

[0073] Although the subj ect matter has been described in language specific to structural features and / or acts , it is to be understood that the subj ect matter defined in the appended claims is not necessarily limited to the specific features or acts described above . Rather, the specific features and acts described above are disclosed as examples of implementing the claims and other equivalent features and acts are intended to be within the scope of the claims .

[0074] It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments . The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benef its and advantages . It wi ll further be understood that reference to ' an ' item may refer to one or more of those items .

[0075] The steps or operations of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate . Additionally, individual blocks may be deleted from any of the methods without departing from the scope of the subj ect matter described herein . Aspects of any of the embodiments described above may be combined with aspects of any of the other embodiments described to form further embodiments without losing the effect sought .

[0076] The term ' comprising ' is used herein to mean including the method, blocks , or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements .

[0077] Although subj ects may be referred to as ' first ' , ' second' , or ' third' subj ects , this does not necessarily indicate any order or importance of the subj ects . Instead, such attributes may be used solely for the purpose of making a difference between subj ects .

[0078] It will be understood that the above description is given by way of example only and that various modifica- tions may be made by those skilled in the art . The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments . Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments , those skilled in the art could make numerous alterations to the disclosed embodiments without departing from scope of this specification .

Claims

CLAIMS1. A thermo roll (1) for a paper and / or a cardboard machine, wherein the thermo roll (1) comprises: a hollow roll body (2) comprising at least one open channel (3) on a surface layer (4) ; and a ceiling (5) on the at least one open channel (3) configured to close the at least one open channel (3) and to form at least one closed channel (6) on the surface layer (4) of the roll body (2) for heat transfer medium.

2. The thermo roll (1) according to claim 1, wherein a longitudinal shape of the at least one open channel (3) or the at least one closed channel (6) along a channel path (10) is one of the following or any combination of the following: arbitrary, constant, variable, continuously variable, and / or combination of constant and variable zones.

3. The thermo roll (1) according to claim 1 or 2, wherein a cross-sectional shape of the at least one open channel (3) is one of the following or any combination of the following: rectangular, conical, inverse conical, triangular, parallelogram, quadrangular, circular, and / or partially circular.

4. The thermo roll (1) according to any one of the preceding claims, wherein a shape of at least one upper edge (8) of the at least one open channel (3) is one of the following or any combination of the following: arbitrary, right angle, sharp, inclined, chamfered, circular, inverse circular, curved, and / or rectangularly formed boundary.

5. The thermo roll (1) according to any one of the preceding claims, wherein a channel width (Wch) between upper edges (8) of the open channel (3) is constant, variable, continuously variable, or combination of constant and variable along the channel path (10) .

6. The thermo roll (1) according to any one of the preceding claims, wherein the at least one open channel (3) is configured to be formed on the surface layer (4) of the thermo roll (1) along the at least one of the following channel path (10) or any combination of the following channel paths (10) : a straight path, a free path, and / or helical path.

7. The thermo roll (1) according to claim 6, wherein the free path is configured to be formed along one or more linear or curved segments, or any combination of one or more linear and curved segments.

8. The thermo roll (1) according to any one of the preceding claims, wherein at least two open channels (3) are configured to be kept separated or crossing their channel paths (10) .

9. The thermo roll (1) according to any one of the preceding claims, wherein the at least two open channels (3) are configured to be located at least partly at the same depth from top surface or at least partly at different depths from a top surface (9) of the thermo roll.

10. The thermo roll (1) according to any one of the preceding claims, wherein a ceiling shape (11) is at least one of the following: arbitrary, inclined, trapezoid, concave, and / or saddle-like.

11. A method for forming a thermo roll (1) for a paper and / or a cardboard machine, wherein the thermo roll (1) comprises a hollow roll body (2) , wherein the method comprises: forming at least one open channel (3) on a surface layer (4) of the roll body (2) ; and forming a ceiling (5) on the at least one open channel (3) ; wherein the ceiling (5) is closing the at least one open channel (3) and forming at least one closed channel (6) on the surface layer (4) of the roll body (2) for heat transfer medium.

12. The method according to claim 11, wherein the at least one open channel (3) is formed by machining.

13. The method according to claim 11 or claim 12, wherein a consumable tool (7) is used to form the ceiling (5) of the at least one closed channel (6) .

14. The method according to claim 13, wherein the consumable tool (7) is rotatable.

15. The method according to claim 13 or claim 14, wherein the consumable tool (7) is configured to travel along a channel path (10) of the at least one open channel (3) , wherein the consumable tool (7) is forced against upper edges (8) of the at least one open channel (3) to deposit material from the consumable tool (7) at least on top of the at least one open channel (3) to form the ceiling (5) of the at least one closed channel ( 6) .

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