The present invention relates to fibrous web machines, preferably to paper, pulp and board machines.

The present invention relates to an end part for a thermo roll, through the forward flow passages of which a forward flow of a heat transfer medium is arranged into the forward passages of which thermo roll shell, and through the return flow passages of which, a return flow of the heat transfer medium is arranged from the return passages of the shell.

The present invention relates also to a method of making an end part for a thermo roll, through the forward flow passages of which end part, a forward flow of a heat transfer medium is arranged into the forward passages of which thermo roll shell, and through the return flow passages of the end part, a return flow of the heat transfer medium is arranged from the return passages of the shell.

Speeds of the multiple nip calendars have increased substantially during the last few years. In order to acquire the required calendaring effect, the surface temperature of the thermo rolls has been required to be elevated up to 200°C to 250°C degrees. The high speed combined with the high surface temperature of the thermo roll means that the thermal capacity transported from the thermo roll is very high; in the new processes it is typically 200 kW/m. In addition to this, using the water moistening before calendar is becoming more common, which also increases the required thermal capacity.

The thermo rolls are usually heated/cooled through passages that have been bored

into the roll shell. In order to reach the required thermal capacity in future, the passages must be arranged very near to the thermo roll surface. Then, the effect of the passages on the circumferential direction of the surface temperature and radial displacement profile (so-called undulation effect) of the thermo roll increases very vigorously. The changes in the surface temperature can cause problems for the paper quality and the changes in the radial displacement, for their part, can cause a barring problem. In order to minimize these adverse effects, the number of passages must be increased considerably and their size must be made respectively smaller.

As is well known, the heat transfer medium flow is passed into the thermo roll shell through the flow passages/bores provided in the end part/end parts of the roll. These bores start from the distributive elements arranged in the end parts and they interconnect with the flow passages/bores in the shell. In some arrangements, there is an individual end passage/bore running from the distributive elements in the end part running to each bore in the shell, in other arrangements, the forward flow bore running from the distributive element is divided at the circumference of the end part, into two shell's forward passages.

With the existing number of flow passages (app. 15-50), the tending side end part is still relatively easy to make. When the number of flow passages goes up to a near hundred, it becomes very difficult, if not impossible, to fit them in the existing end parts together with the bolt holes needed for connecting the end part and the shell.

The traditional end part structure is by no means very maintenance-friendly. In the new calendaring processes, the oil temperatures are high; whereupon the service lives of the seals and insulation bushing are presumably shorter than the service life of the thermo roll itself, thus making the above mentioned parts the object of maintenance in the thermo roll. In order to, e. g. check the flow passages, change the seals or change the insulation bushings of the shell, the entire end part must be detached.

After detaching and attaching the end part, the roll shell has to be ground and the thermo roll has to be balanced. Usually, only the thermo roll manufacturer can carry out especially the balancing, whereupon the thermo roll could be transported possibly for miles even for a very simple maintenance work.

The known roll end part, heated with a heat transfer medium, e. g. water, steam or oil, comprising an end flange and an axle journal, is complicated and expensive to produce, because it includes a large number of blind hole bores in different directions.

During manufacturing, the flow passages have typically been provided as blind hole bores or through bores that have been plugged and that require special precision. One drawback in a system of blind hole bored passages is constituted by sharp angles, which are produced in it and which are not optimal from the viewpoint of the flow of the medium, but which cannot be avoided in drilling.

The roll bearing of the thermo roll is under a considerable heat load, especially because of the high temperatures that are now required from the heating medium, and lubricating the hot bearing is problematic. In order to reduce the heat load of the roll bearing, a special vacuum insulation sleeve has sometimes been used inside the axel journal, and manufacturing this sleeve also causes additional costs.

A general object of the present invention is to eliminate or at least substantially reduce the above drawbacks and weaknesses, and to make the manufacturing of the thermo roll end part structure with the large number of flow passages as easy as possible. An additional object of the invention is to facilitate the maintenance of the system of flow passages, formed of the above-mentioned heat transfer medium passages, and its'components.

The above-mentioned objects have been provided by the present invention, whose special characteristics have been defined in the accompanying set of claims.

The thermo roll end part is characterized in that, at least some of the forward flow passages of the end part and/or at least some of the return flow passages of the end part are disposed outside the end part body, which comprises an axle journal and a flange.

Then, a forward side connecting element has preferably been arranged to be the forward flow passage outside of the end part body, and/or a return side connecting element has been arranged to be the return flow passage outside the end part body, which connecting element has been made of a tube or a pipe and preferably arranged to be detachable.

According to an application of the invention, on the forward side, first forward flow passages that are preferably arranged to be radial passages on the circumference of the axle journal, are provided in the axle journal, and according to another application, first forward flow passages that are preferably formed as straight passages, are provided in the flange, for directing the forward flow of the heat transfer medium through the forward passage, outside of the end part.

According to an application of the invention, second forward flow passages that are preferably formed as straight passages, are arranged in the flange, for directing the forward flow of the heat transfer medium from the outside of the end part, into the forward passages of the thermo roll shell.

According to an application of the invention, on the return side, first return flow passages that have preferably are formed as straight passages, are provided in the flange, for directing the return flow of the heat transfer medium, from the return passages of the thermo roll shell into the end part and onwards outside the end part.

According to an application of the invention, second return flow passages that are preferably formed as straight passages, are provided in the flange, and according to another application, second return flow passages that are preferably formed as the radial passages on the circumference of the axle journal, are provided in the axle journal, for directing the return flow of the heat transfer medium from the outside of the end part into the end part and onwards into the return passage.

According to an application of the invention, the connecting element that is arranged to be the forward flow passage and/or return flow passage, is insulated, most conveniently with an external layer of thermal insulation material, such as a thermal insulation pipe.

According to an application of the invention, the forward flow passage, such as the connecting element of the forward side made of pipe or tube, and arranged outside the body of the end part, and/or the return flow passage, such as the connecting element of the return side made of pipe or tube, and arranged outside the body of the end part, are provided with a monitoring device for monitoring the heat transfer medium, preferably flow passage specifically, e. g. regarding the temperature, pressure or flow velocity or for controlling the flow of the heat transfer medium, preferably flow passage specifically.

According to an application of the invention, in order to protect the connecting elements, a protective cover is arranged on the end part, which protective cover is preferably detachable.

It is characteristic for the thermo roll end part, that the end part comprises connecting elements that are arranged between the forward flow/return flow passages and the forward/return passages of the shell so that, the forward flow is, by using the connecting element/elements, distributed from the respective single forward flow

passage of the end part into at least two forward passages of the shell, and the return flow is, by using the connecting element/elements, combined of at least two of the return passages of the shell into the respective single return flow passage of the end part.

According to an application of the invention, the connecting element is made of tube or pipe.

According to an application of the invention, in order to protect the connecting elements, a protective cover is arranged on the end part.

According to an application of the invention, the protective cover is detachable.

According to an application of the invention, the forward flow passages and the return flow passages of the end part are bores.

According to an application of the invention, the forward flow passages and the return flow passages of the end part are arranged on the same circumferentially directed sectional plane in the end part.

The method according to the invention is mainly characterized in that, at least some of the forward flow passages of the end part and/or at least some of the return flow passages of the end part are disposed outside the end part body, which comprises an axle journal and a flange.

According to an application of the invention, a forward side connecting element is arranged to be the forward flow passage outside of the end part body, and/or a return side connecting element is arranged to be the return flow passage outside the end part body, which connecting element is made of a tube or a pipe and preferably arranged

to be detachable.

According to an application of the invention, in order to direct the forward flow of the heat transfer medium outside the end part from the forward passage, first forward flow passages are provided in the axle journal, preferably arranging them as radial passages on the circumference of the axle journal.

According to an application of the invention, in order to direct the forward flow of the heat transfer medium outside the end part from the forward passage, first forward flow passages are provided in the flange, preferably arranging them to be straight passages.

According to an application of the invention, in order to direct the forward flow of the heat transfer medium from the outside of the end part into the forward passages of the thermo roll shell, second forward flow passages are provided in the flange, preferably arranging them to be straight passages.

According to an application of the invention, in order to direct the return flow of the heat transfer medium from the return passages of the thermo roll shell into the end part and onwards outside the end part, first return flow passages are provided in the flange element, preferably arranging them to be straight passages.

According to an application of the invention, in order to direct the return flow of the heat transfer medium from outside the end part into the end part and onwards into the return passage, second return flow passages are provided in the flange, preferably arranging them to be straight passages.

According to an application of the invention, in order to direct the return flow of the heat transfer medium from outside the end part into the end part and onwards into the

return passage, second return flow passages are provided in the axle journal, preferably arranging them to be radial passages on the circumference of the axle journal.

According to an application of the invention, a connecting element, which is arranged to be a forward flow passage and/or a return flow passage, is insulated, most conveniently with an outside thermally insulating layer of thermal insulation material, such as a thermal insulation pipe.

According to an application of the invention, a forward flow passage, such as a forward side connecting element made of pipe or tube, and arranged outside the body of the end part, and/or a return flow passage, such as a return side connecting element made of pipe or tube, and arranged outside the body of the end part, are provided with a monitoring device for monitoring the heat transfer medium, preferably flow passage specifically, e. g. regarding the temperature, pressure or flow velocity, or for controlling the flow of the heat transfer medium, preferably flow passage specifically.

According to an application of the invention, in order to protect the connecting elements, a protective cover is arranged on the end part, which protective cover is preferably detachable.

Regarding the other characteristics and advantages of the invention, reference is being made to the dependent claims of the set of claims and to the special part of following the description, where a detailed description is made, but with only as an example, of some preferred embodiments of the invention and their application.

The invention is described in the following with reference to the accompanying figures, which illustrate the thermo roll end part according to the invention, without, however, limiting the invention solely to what is indicated in the figures.

Figure 1 shows a partial cross section of a known flow passage arrangement in connection with a thermo roll end part.

Figure 2 shows a cross section I-II of the Figure 1.

Figure 3 shows a cross section II-II of the Figure 1.

Figure 4 shows a partial cross section of the flow passage arrangement in connection with the thermo roll end part according to a preferred embodiment of the invention.

Figure 5 shows a section of the thermo roll end in Figure 4, seen from the direction III, without a protecting cover of the end part.

Figure 6 shows a cross section IV-IV of Figure 4.

Figure 7 shows a partial cross section of the flow passage arrangement according to a preferred embodiment of the invention in connection with the thermo roll end part.

Figure 8 shows a partial cross section of an insulated flow passage arrangement in connection with the thermo roll end part according to a preferred embodiment of the invention.

Figure 9 shows a partial cross section of the flow passage arrangement according to an embodiment of the invention in connection with the thermo roll end part, provided with a heat transfer medium monitoring device and without a protecting cover of the end part.

Figure 10 shows a partial perspective view of the thermo roll end part, provided with

a partially external heat transfer passage system.

An example of a known arrangement for the flow passage of the thermo roll end part is shown in Figures 1,2 and 3. Figure 1 shows the end part 2 of the other end of the thermo roll 1 being attached to the shell 20 with an outer diameter 20a and inner diameter 20b. The flow of the heat transfer medium is provided into the thermo roll 1 end part 2 through the forward distributive element 17 and correspondingly, it is provided from the end part 2 through the return distributive element 18, which distributive elements 17,18 are held in place by a cover 19 connected to the end part 2.

The flow is directed from the thermo roll 1 end part 2 directly into the thermo roll shell 20, that is, without intermediate elements, from the flow passages/bores 3,4 of the end part 2, into the flow passages 21,22 of the shell 20, and vice versa. In the example structure, the forward flow passage 3 and the return flow passage 4 of the end part, except for the external part of the end part 2, are paired on the same circumferentially parallel sectional plane. In that case, more room is given for the bolt holes 5 in the circumferential direction. A more specific illustration of the disposition of the forward flow passage 3 and return flow passage 4 in the external part of the end part 2 i. e. on the periphery area of the end part 2, is given in the sectional views in Figures 2 and 3. The flow of the example structure is such, that each forward flow passage 3 has its own return flow passage 4. Then, distributing the forward flow from the one forward bore 3 of the end part 2, coming out of the forward distributive element 17, into several forward bores 21 of the shell 20, and combining the return flow coming from the several return bores 22 of the shell 20 into the one return bore 4 of the end part 2, and onwards into the return distributive element 18, is practically impossible. This would, naturally, be possible if the forward and return bores connected to the distributive elements 17,18, would be distributed into several bores with different distributing diameters. However, the difference between the

distributing diameters should be relatively large, which, in practice, would mean that, the dividing of either the forward or return passages should occur inside the distributing diameter of the bolt holes 5. In this case, the advantage from distributing would be partly sacrificed, that is, the space required for the bolt holes 5 connecting the end part 2 and the shell 20 would be used. When the number of flow passages 21, 22 is very large, this simply is not possible.

The cross section I-I of the Figure 1 shown in the Figure 2, and the cross section II - II of the Figure 1 shown in the Figure 2, illustrate the disposition of the flow passages 3,4 ; 21,22 and the bolt holes 5.

Figures 4, 5 and 6 show a preferred embodiment of the structure according to the invention. In this new structure, the manufacturing problem and the problem of space in the end part 12 is eliminated by distributing the flow from the respective single forward flow passage 13 of the end part, into several forward passages 21 of the shell 20, and correspondingly by combining the flow from the several return passages 22 of the shell into the respective single return flow passage 14 of the end part, using the separate connecting elements 13a, 14a, e. g. tubes or pipes. Because of the connecting elements 13a, 14a, the outer diameter of the actual end part 12 is considerably smaller than the outer diameter of the shell 20, in the category of 160 mm. The connecting elements 13a, 14a are protected with a detachable protecting cover 12', connected to the end part 12, and the structure of which is not defined here in any more detail. Nor is the surface 12a structure of the actual end part 12, which is protected by the protecting cover 12', fixed.

The structure of the actual end part 12 is, according to the Figures 4,5 and 6, very simple. The forward flow/return flow passages/bores 13,14 of the end part 12 are easy to make, since they can be made as straight bores. Thus, the forward flow and return flow passages 13,14 of the end part 12 are not formed by combining from

several bores, as in the end part 2 according to the known art and illustrated in Figure 1. The greatest advantage can be had from the structure according to the invention when the flow passages 13,14 of the end part 12 are arranged on the same circumferentially sectional plane, as shown in the Figure 4, but this is not obligatory.

In the arrangement illustrated in Figures 4-6, the flow is directed from the actual end part 12, into the shell 20 and vice versa, using the separate connection elements 13a, 14a, e. g. tubes or pipes. Then the distributing the flow from the respective single forward flow passage 13 of the end part 12, into several forward passages 21 of the shell 20, and correspondingly, combining the flow from the several return passages 22 of the shell 20 into the respective single return flow passage 14 of the end part, is easy. A space S between the end part 12 and the protecting cover 12'must be big enough in the radial direction for the connecting elements 13a, 14a of the forward flow 13 and the return flow passages 14 of the end part 12 to be able to overlap. At these places, the connecting elements 13a, 14a can be made slightly thinner in the radial direction, thus saving space.

Enough space is arranged around the bolt holes 15. This is achieved normally if the thickness T of the end part 12, measured from the inner diameter 20b is about 100 mm. In the existing thermo rolls the minimum thickness of the shell is normally about 180 mm, though often the actual thickness of the shell 20 is even notably bigger. If the thickness of the connecting elements 13a, 14a, at the place where they are overlapping, is e. g. 25 mm, then the free space S between the end part 12 and the protecting cover 12'must be a minimum of 50 mm. If, in addition to this, the thickness of the protecting cover 12'in the direction of the thermo roll 1 radius, is e. g. 20 mm, then the thickness in the direction of the radius of the end part 12, according to the new structure, is, including the protecting cover 12', from the inner diameter 20b of the shell 20, a minimum of 170 mm. Thus, there is enough space left for the bolt holes 15 in the radial direction.

The question of to how many forward passages 21 of the shell 20 the flow is distributed from the single forward flow passage 13 of the end part 12, or from how many return passages 22 of the shell 20 the flow can be distributed into the single return flow passage 14 of the end part 12, has not been fixed in any way. If the ratio between the number of flow passages 13,14 of the end part 12 and the number of passages 21,22 of the shell is 1: 2, e. g. as illustrated in Figures 5 and 6, and the flow passages 13,14 of the end part 12 are on the same circumferentially sectional plane, as in Figures 4, 5 and 6, then the length of the circumferential sector between the flow passages 13,14 of the end part 12, is relatively already four times longer in comparison with the circumferential sector between the passages 21,22 of the shell 20. For most cases this is enough. Naturally, the diameter of the flow passages 13,14 of the end part 12 can be larger than the diameter of the passages 21,22 of the shell 20, whereupon the flow velocity can be maintained approximately constant.

Figure 5 shows a section of the thermo roll 1 end in Figure 4, seen from the direction III, without the protecting cover 12'protecting the connecting elements 13a, 14a of the end part 12, and Figure 6 shows a cross section IV-IV of the Figure 4.

The structure illustrated in Figures 4-6 makes the distribution of the flow from the each single flow passage 13,14 of the end part 12, into the several passages 21,22 of the shell 20, structurally easy. There is naturally a lot of work in manufacturing, attaching and maintaining the connecting elements 13a, 14a, but the work is simple.

If the protecting cover 12'over the connecting elements 13a, 14a, which can also be used in some other parts of the process, is detachable, e. g. is attached with bolts (not shown), then the considerable advantage of the structure according to the invention is that the maintenance operations of the flow passage system 13,14 ; 13a, 14a; 21,22, becomes considerably simpler. After detaching the protecting cover 12', the cleanness of both the end part 12 flow passages and the shell 20 flow passages 21,22

can be checked, and inter alia the connecting elements 13a, 14a themselves and their seals and the insulating pipes of the end part 12 bores 13,14 and the shell 20 insulation bushing, can be changed. There is no need to detach the end parts 12, whereupon the there is no need to grind the shell 20 or balance the thermo roll 1. As a result, the above mentioned maintenance operations can be performed on location in the paper mill.

The embodiments of the end part manufactured with the method according to the invention are illustrated in the Figures 7,8, 9 and 10. Heat transfer medium, such as the heat transfer oil, water or steam should be transferred into the application, such as the thermo roll shell 20, as hot as possible, and the heat transfer medium should be held in the heat transferring body of the end part 32 as short a time as possible, so that heat is not transferred in excess into a place where it is not needed, or into a place where heat could cause damage, such as to roll bearings, and so that the heat of the heat transfer medium is not wasted. Thus, the end part 32 can be manufactured so, that the heat transfer medium passages are disposed outside of the load bearing and heat transferring body of the end part 32. These forward flow passages and return flow passages according to the invention and provided outside the end part 32 are arranged by using the connecting elements 13a, 14a that are preferably detachable tubes or pipes, outside the axle journal 32'and outside the flange 32". Because the tubes or pipes etc. forming the connecting elements 13a, 14a, can be easily arranged so, that they don't contain sharp angles or other flow obstructions, they are optimal for the flow. The best effect for reducing the effective time of the heat transfer medium in the end part 32, and for reducing the heat stress of the roll bearings (not shown) is accomplished when as long portions as possible of the above mentioned heat transfer passages 13a, 14a are disposed outside of the body of the end part 32, which includes the axle journal 32'and the flange 32". Thus, the invention may reduce heat stress of the roll bearing by reducing the heat transfer into the roll bearing mounted on the journal (not shown) of the axle journal 32', whereupon no expensive

and complicated special arrangement provided with a vacuum insulation sleeve need to be used.

Preferably according to the method of the invention, the heat transfer medium flow passages 13a, 14a that are disposed outside the body of the end part 32, are most conveniently insulated with a thermally insulating layer of thermal insulation material 49, such as a thermal insulation pipe, provided outside the connecting element 13a, 14a, preferably a tube or a pipe, which is a part of the flow passage, preventing the heat transfer medium from cooling unnecessarily in the thermo roll shell 20 before the heat is emitted, and preventing the heat from transferring into the adjacent roll bearings. The insulation arrangement of the flow passages of the thermo roll end part 32 according to the method, is preferred and simple in comparison with the known cavities formed inside the axle journal, into which a vacuum can be arranged, or into which thermally insulating material can be provided.

Using the invention prevents the heat transfer medium from cooling in the end part 32, and enables the transfer of the heat transfer medium, as hot as possible, to the roll shell 20 area, for benefiting the fibrous web handling process. In addition to this, using the invention can facilitate the maintenance of the flow passage system, formed by the heat transfer medium flow passages, and its components, both in the roll shell 20 and in the end part 32 itself, without having to detach the end part from the roll shell for maintenance.

According to the Figures 7-9, the forward flow of the heat transfer medium is transferred into the thermo roll end part 32 through the forward passage 47 of the axle journal 32', and accordingly, the return flow is transferred from the end part 32 through the return passage 48 of the axle journal 32', which forward passage 47 can be e. g. formed of the forward passage inside the axle journal 32'connected to the forward distributive element, known per se, and which return passage 48 can, e. g. be

formed of the return distributive element, known per se, connected e. g. to the return passage inside the axle journal 32'.

The forward flow is directed, e. g. in a way illustrated in the Figures 7-9, from the forward passage 47 of the axle journal 32'outside the axle journal with the first forward flow passages 47'that have been arranged to be radial passages on the circumference of the axle journal 32'with a suitable relative spacing, without compromising the axle journal 32'strength. These first forward flow passages 47'can be made as the flow passages, simply by drilling straight holes that are parallel to the end part 32 radius, in the area of the axle journal 32', which area is disposed preferably between the flange 32"of the end part and the bearing journal (not shown) of the axle journal 32'. Outside the end part 32, the forward flow is directed using the preferably detachable and, according to the Figure 8, preferably insulated 49 forward side connecting elements 13a, e. g. with tubes or pipes, into the flange 32", where, provided through the flange 32", are the second forward flow passages 47" preferably being drilled through the flange, for directing the flow into the forward passages 21 provided in the thermo roll shell 20. Then, the forward flow is directed, using the second forward flow passages 47", a relatively short distance inside the flange 32". The forward flow passages 47"are located preferably at a corresponding location to the forward passage 21 of the heat transfer medium, e. g. the periphery bore on the thermo roll shell 20.

The forward flow from the forward passage 47 of the end part 32 is arranged, as illustrated in Figures 7-10, by a respective single non-branching flow passage, being comprised of a first forward flow passage 47', a connecting element 13a, and a second forward flow passage 47", into a respective single shell 20 forward passage 21. However, the forward flow can, e. g. due to lack of space when the number of flow passages in the roll shell 20 increase up to one hundred, be arranged to be distributed from a respective single first forward flow passage 47'into several, e. g.

two of the second forward flow passages 47", by e. g. distributing the respective forward flow in the forward side connecting element 13a.

The return flow is directed from the return passage 22 of the heat transfer medium of the thermo roll shell 20, in a way illustrated in e. g. Figures 7-9, through the flange 32"of the end part 32. The return flow is thereby directed using the first return flow passages 48'for a relatively short distance inside the flange 32", outside the heat transferring material of the flange. The first return flow passage 48'is a flow passage situated near the flange 32"periphery and manufactured preferably by straight drilling, and located preferably at a corresponding location to the return passage 22 of the heat transfer medium, e. g. the periphery bore in the thermo roll shell 20. Outside the end part 32, the flow is directed using the detachable and, according to Figure 8, preferably insulated 49 return side connecting elements 14a, e. g. with tubes or pipes, from the first return flow passages 48'into the second return flow passages 48", being, in the example embodiments illustrated in Figures 7-9, in the flange 32"near the area, where the axle journal 32'is connected to the flange 32". The second return flow passages 48"have been provided in the end part 32, e. g. in the flange 32", to be simple axially aligned straight bores that lead into the return passage 48 of the end part 32, being provided using a distributive element connected in a known manner per se to the end part 32 and an axially aligned return flow passage located inside of the axle journal 32'and being connected to the distributive element.

The return flow from the respective single return passage 22 of the shell 20 is arranged into the return passage 48 of the end part 32, with a respective single non- branching flow passage, which is comprised of a first return flow passage 48', a connecting element 14a and a second return flow passage 48". However, the return flow can, e. g. due to lack of space when the number of flow passages in the roll shell 20 increase up to one hundred, be arranged to be combined from a respective several, e. g. two of the first return flow passages 48'into a single second return flow passage

48", by e. g. combining the respective return flow in the return side connecting element 14a. The question of into how many second forward flow passages 47"and onwards forward passages 21 of the shell 20 the flow can be distributed from the single first forward flow passage 47'of the end part 32, or from how many return passages 22 of the shell 20 and onwards, from the first return flow passages 48', the flow can be combined into the respective single second return flow passage 48"of the end part 32, has not been fixed in any way.

The end part 32, and especially its flange 32"can be formed axially short and less massive than the end parts including the known flow passage arrangements, since, in the preferred application of the invention, only a short portion of the forward flow passages have been arranged in the flange 32"area, thereby reducing the heat loss of the heat transfer medium in the end part 32. Furthermore, no voluminous inclined radial bores, such as e. g. the return flow passage 4 illustrated in Figure 1, are arranged in the flange 32"area. Because in the embodiment of the end part 32 manufactured according to the method of the invention, the flange 32'is not provided with complicated blind hole bores or plugged bores, it is possible to form the flange 32' short in axial direction, without compromising the end part 32 strength. Furthermore, the flow passages are, for the flow and the manufacturing, optimally straight and manufactured in axial direction of the end part 32. Thus, also the disposition of the bolt holes 35, illustrated in Figure 10, is simple and there is enough space around them in the radial direction. The end manufactured according to the invention with a specific number of passages, can preferably be used in connection with several different roll shell flow passage arrangements, and the number of both forward and return passages in the roll shell can be freely changed by changing the number of forward flow connecting elements 13a and the number of return flow connecting elements 14a and the way of connecting outside the end part 32.

The deposition of the first forward flow passages 47'and the second return flow

passages 48"does not necessarily be performed according to Figures 7-10. It is also possible, that some of the first forward flow passages 47'or all the first forward flow passages 47'are deposited in the flange 32"area, and it is possible, that some of the second return flow passages 48"or all the second return flow passages 48"are deposited in the axle journal 32'area, always allowing for the strength required from the end part 32.

The connecting elements 13a, 14a have, in Figures 7 and 8, been protected by a detachable protecting cover 12', connected to the end part 32, and the structure of which is not defined here in any more detail. Nor is the surface structure 32a of the actual end part 32, which is protected by the protecting cover 12', fixed. The purpose of the protecting cover 12'is to prevent foreign objects or personnel from impacting with or getting caught in the connecting elements and to prevent the collection of dirt, therefore the protecting cover has to be sufficiently tight. Additionally, the protecting cover must be, for maintenance purposes, easily detachable/attachable and movable.

Manufacturing the actual end part 32 is, according to Figures 7-10, very easy. The forward flow and return flow passages/bores 47', 47", 48', 48"of the end part 32 are easily made since they can be made as straight bores. Thus, the forward flow an return flow passages 47', 47", 48', 48"of the end part 32 are not formed of several bores that are at a relative angle and that are connected one after another, as in the end part 2 according to the known art and illustrated in Figure 1.

Figure 9 shows a partial cross section of the flow passage arrangement with the thermo roll end part 32 according to an embodiment of the invention, provided with a heat transfer medium monitoring device/s 50, and without the protecting cover 12'of the end part, which is provided for protecting the connecting elements 13a, 14a. The heat transfer medium monitoring device 50 is provided for monitoring the heat transfer medium, preferably forward flow passage specifically, and/or return flow

passage specifically, and on the other hand, the monitoring device 50 can be used for controlling the flow of the heat transfer medium, preferably forward flow passage specifically, and/or return flow passage specifically. The monitoring device 50 can perform the monitoring of the heat transfer medium; it can, e. g. monitor the temperature, pressure or flow velocity. The monitoring device 50 can be arranged to perform operations for controlling the flow of the heat transfer medium, whereupon it can include e. g. an adjustable valve. The monitoring device 50 can be easily disposed, according to Figure 9, outside the body of the end part 32, in the connecting elements 13a and/or 14a. The question of how many connecting elements the monitoring device 50 is disposed to, and which is the distribution of the monitoring devices in the connecting elements, is not fixed. The connecting element 13a, 14a provided with the monitoring device 50 is preferably also provided with an insulation 49 illustrated in Figure 8.

Figure 10 shows a partial perspective view of the thermo roll end part 32, provided with a heat transfer passage system partially outside the axle journal 32'and the flange 32", comprising of the forward side connecting elements 13a and the return side connecting elements 14a.

The method of manufacturing the end part according to the invention facilitates the accommodation of a larger number of flow passages than what is used in existing end parts, and the accommodation of the number of bolt holes required of connecting the shell. There is naturally a lot of work in manufacturing, attaching and maintaining the connecting elements 13a, 14a, but the work is simple. If the protecting cover 12'over the connecting elements 13a, 14a, which can also be used in some other parts of the process, is detachable, e. g. is attached with bolts (not shown), then the considerable advantage of the structure according to the invention is that the maintenance operations of the flow passage system 47,47', 47" ; 21,22 ; 48', 48", 48 becomes considerably simple. After detaching the protecting cover 12', the cleanness of both

the end part 32 flow passages and the shell 20 flow passages 21,22 can be checked, and inter alia the connecting elements 13a, 14a themselves and their seals and the insulating pipes of the end part 32 bores can be changed. There is no need to detach the end parts 32, whereupon the there is no need to grind the shell 20 or balance the thermo roll. As a result, the above mentioned maintenance operations can be performed on location in the paper mill.

The invention has been described above referring to only some of its preferred embodiments. This should not in any way limit the invention, and as it is apparent for those skilled in the art, many alternative arrangements, combinations and variations of the special features of the above mentioned embodiments are possible within the inventive idea and in its scope defined in the appended set of claims.

The thermo roll end part refers in this description to the end part of the thermo roll, through which the flow is transferred into the shell/out of the shell. This can be the end part of the roll's tending side or the end part of the roll's driving side, or even both. Although the focus now have been on the structure, where the flow is introduced and transferred through the same end part, the structure can however be applied to a situation, where both end parts are used for introducing/transferring the flow.