CN116971199A - Pressure shaft of shoe roll, shoe roll and long nip press - Google Patents

Abstract

A pressure shaft (18) having an I-shaped profile in base cross section and comprising: a first flange (19.1) and a second flange (19.2) and a web (20) present between them; a recess (23) adapted to one side of the first flange, a loading element (16) adapted to the pressure shaft for the shoe (15); a flange portion of the inlet side (A) of the first flange (21.1) and a flange portion (21.2) of the outlet side (B) of the first flange are arranged for a rear support (25) of the shoe. The pressure axis has an inertial axis structure (XYZ), wherein the two inertial axes (Y, Z) are arranged parallel to a cross-sectional plane (22) of the pressure axis. The cross section of the first flange is adapted such that the inertia axis (Z) of the two inertia axes parallel to the cross-section plane is adapted to be inclined in the direction of the inlet side of the first flange. The invention also relates to a shoe roll and a long nip press.

Description

Pressure shaft of shoe roll, shoe roll and long nip press

Technical Field

The invention relates to a pressure shaft for a shoe roll, the basic cross section of which is an I-shaped profile and comprises:

a first flange and a second flange and a connecting piece located therebetween,

recesses adapted to the sides of the first flange, loading means for the shoe (Schuhs) adapted to the pressure shaft,

a flange portion of the inlet side of the first flange,

-a flange on the outlet side of the first flangeA portion arranged for rear support of the shoe portion, and the pressure shaft has an inertia shaft structureThe two inertia axes of the inertia axis structure are arranged parallel to the cross-sectional plane of the pressure axis. The invention furthermore relates to a shoe roll and a long nip press.

Background

So-called long nip presses are currently known from the press section of paper and board machines. The long nip press consists of so-called shoe rolls and counter rolls, wherein the shoe rolls can be loaded against the counter rolls, for example. Here, an elongated nip is formed between the rolls in the machine direction. In this nip, the surface of the shoe follows the shape of the surface of the counter roll.

The mantle portion of the shoe roll is formed by a belt loop. Which rotates around the shoe, for example fastened to the end flange of the roll. The nip-forming, medium-lubricated shoe is located inside the belt loop and has loading and support mechanisms. The shoe and the loading mechanism are supported on a pressure shaft located inside the shoe roll and made of, for example, casting, which is generally I-shaped in profile in the loading zone with respect to the base cross section.

The cross-sectional profile of the pressure shaft known from the prior art is premised on a large cross-section. This may lead to difficulties in draining the oil, for example.

Recent developments have brought the width of the machine to approximately ten meters, and may have exceeded this width. Bending caused by forces directed towards the shoe roll (nip force, force in the machine direction) can be taken into account by increasing the material thickness of the pressure shaft flange. This achieves the reinforcement requirement but at the same time increases the weight and manufacturing costs of the shaft. Furthermore, the profile of the pressure shaft must therefore also be large in order to obtain a working space for the treatment (e.g. pipe and/or bend correction) to be performed thereon.

Disclosure of Invention

The object of the present invention is to provide a pressure shaft for a shoe roll which is lighter in construction but has improved bending properties (Verbiegngseiginschaften). It is also an object of the present invention to provide a shoe roll and a long nip press

In the present invention, the inertia shaft structure of the pressure shaft is rotated as follows: one of its inertia axes is adapted to extend obliquely on one side of the shoe in the direction of the inlet side of the first flange. With the present invention, the burden of the pressure shaft structure can be reduced, but the loading characteristics can be kept unchanged. With the present invention, the forces are also balanced and thus a more slender, lighter pressure shaft is obtained.

The cross section of the flange is asymmetrical on the side of the recess of the shoe arranged for the pressure shaft. The first flange of the pressure shaft is thus adapted in cross section to rotate the inertial shaft structure of the pressure shaft. More specifically, the rotation of the inertial shaft structure is performed as follows: one of the two inertia axes parallel to the pressure axis cross-section plane is adapted to be inclined in the direction of the inlet side of the first flange, wherein in the known pressure axis the relevant inertia axis is parallel to the web or nip force of the pressure axis or slightly inclined in the direction of the outlet side of the first flange.

By means of the invention, the inertia shaft structure of the pressure shaft will deflect from the loading direction. More specifically, in the present invention, the inertia shaft structure of the unloaded pressure shaft is rotated in the direction of the flange portion of the inlet side of the first flange, or in the direction of the front flange. The pressure shaft is bent parallel to the nip due to the nip force and, at the same time, the bending of the pressure shaft in the Machine Direction (MD) in the direction of the inlet side of the nip is reduced. The forces directed to the side of the flange portion on the outlet side of the first flange or the rear flange in turn straighten the pressure shaft in the machine direction and bend it in the direction of the nip outlet side. By means of the rotation of the inertia axes, with a narrow pressure axis profile, a tight (knapp e) bending limit in the machine direction is achieved. By the invention, the pressure shaft remains substantially straight when the forces during operation are directed towards the pressure shaft and the shoe roll. This also ensures the function of the shoe in the shoe roll to some extent. In other words, the shoe can move without clamping.

By the present invention, this finer pressure shaft structure also provides more space inside the shoe roll. This in turn gives a greater degree of freedom in the arrangement of, for example, the piping and equipment in the shoe roll. According to one embodiment, the pressure shaft is also bypassed by a modular oil drain, for example, due to a narrower pressure shaft profile.

By means of the pressure shaft according to the invention, by means of the rotation of the inertial shaft structure, it is also possible to create a suitable working space for the machining to be carried out on the shaftOn the other hand, in order to correct the bending, the implementation requirements for machining on the pressure axis to significantly increase the local stress level are reduced or even omitted. In particular, it relates to the case where the supporting space is very wide. The profile of the web is also better symmetrical by the pressure shaft according to the invention, in particular between the drive side and the operating side. Other additional advantages realized by the present invention are presented in the description section and the claims.

Drawings

The invention will be described more precisely below with reference to the accompanying drawings, but is not limited to the following application forms shown, in which:

figure 1 schematically shows an example of a long nip press as seen in the machine direction,

figure 2 schematically shows an example of a shoe roll without a mantle as seen in the machine direction,

FIG. 3 shows an example of the pressure shaft of a shoe roll according to the prior art in a cross-sectional view, and

fig. 4 shows an example of the pressure shaft of a shoe roll according to the invention in a cross-sectional view.

Detailed Description

An example of the application environment of a pressure shaft 18 according to the invention and a shoe roll 11 comprising such a pressure shaft on a fibre-web machine, such as a paper or board machine, is schematically shown in a rough schematic view in fig. 1. The so-called long nip press 10 is shown schematically in the figure, seen in the machine direction.

The long nip press 10 is formed in a known manner by a long shoe roll 11 and its counter roll 12. The shoe roller 11 can be loaded in a known manner against a counter roller 12 arranged opposite thereto. Here, an elongated nip 3 is formed in the machine direction between the rolls 11, 12, the press type being known as such.

The shoe roll 11 comprises an elongated pressure shaft 18, which is typically made of metal and is cast. The outer mantle 17 of the shoe roll 11 rotates around a pressure shaft 18. The housing 17 may be formed, for example, of a belt loop that is removably mounted on the shoe roller 11. The belt loop may be fastened from the end to the circular end flange 40 of the shoe roll 11. Furthermore, the flange is rotatably fastened axially on, for example, the end 39 of the pressure shaft 18 of the shoe roller 11.

The shoe 15 of the shoe roller 11, which is fitted to the pressure shaft 18, is located inside the outer mantle 17. The shoe 15 is located on the shoe roller 11 on one side of the counter roller 12. The shoe 15 has a loading element 16, which is also arranged in the housing 17, similar to the shoe 15. The shoe 15 of the shoe roll 11 forms the aforementioned nip 13 with the counter roll 12. The shoe 15 (sometimes also referred to as a pressure shoe or a sliding shoe) is elongated and is medium lubricated (mediageschmitt) between the sliding surface of the outer cover 17 and the shoe 15.

The loading element 16 of the shoe 15 may for example comprise one or two hydraulic cylinder arrangements with loading pistons, which act on the shoe 15, for example by means of a pressure plate or directly. During loading and due to the shape of the shoe 15, the roll section (Walzensegment) of the counter roll 12 becomes somewhat "in" the shoe roll 11, thereby making the nip 13 longer in the machine direction (e.g., 100-320 mm). The counter roll 12 may also include a shoe loading system (not shown).

Fig. 2 schematically shows an example of the shoe roll 11 in a cross-sectional view without the mantle 17 as seen in the machine direction. In this illustrated application form, the shoe roll 11 further comprises a collector 27 adapted therein for collecting (zirkulierend) medium present between the shoe 15 and the mantle 17 to be arranged in the shoe roll 11, lubricated and circulated by the rotational movement, and removing it from the shoe roll 11. The lubricant carried by the cover 17 and fed onto the shoe 15, for example, is removed from the shoe roll 11 by means of the collector 27. The collector 27 may be at least one elongated slot 32 arranged in the longitudinal direction of the shoe roll 11.

The collector 27 may be equipped with one or more pipe joints 29. The medium is led out of the collector 27 via a pipe connection 29. One or more discharge channels 30 for the medium collected by the collector 27 are connected to the pipe connection 29. The medium is discharged through the discharge passage 30 and guided out from the shoe roller 11 via the end portion. The discharge channel 30 may, for example, be connected to a main line 24 arranged near the connection piece 20 of the pressure shaft 18, which main line 24 leads the medium out of the shoe roll 11.

The discharge channel 30 may include a flexible bellows (Balg) 45. The flexible bellows 45 allows movement of the shoe 15 and collector 27 connected thereto, such as loading, unloading and various inclinations. The main line 24 is fastened to the connection piece 20 of the pressure shaft in the longitudinal direction of the pressure shaft 18, for example by means of a fastening fork 44. The main line 24 extends from the shoe roll 11 via the end through a window/opening 37 adapted to the end of the pressure shaft 18 and a hollow axle pin (Wellenstift).

The shoe 15 shown in fig. 1 and 2 may be made of a material such as steel or aluminum. The shoe 15 comprises a configuration channel (not shown) for feeding a pressurized lubrication medium between the shoe 15 and the outer mantle 17 of the shoe roll 11 through the shoe 15. The configuration channels may include, for example, horizontal and vertical holes made in the shoe 15. Here, the configuration channels arranged in the shoe 15 may include, for example, feed channels existing in the longitudinal direction of the shoe 15. Further, the oil is fed into the pocket space of the shoe 15 between the shoe 15 and the flexible belt loop serving as the outer cover 17 through the hole. The medium introduced into the pocket space is introduced in the shoe 15 into a configuration channel adapted thereto, which has channel elements 31 assigned to the shoe roller 11 for introducing the medium into the shoe.

In the case of the application form shown, the opening 41 arranged on the pressure shaft 18 is located in the vicinity of the web 20 of the pressure shaft 18 for the channel element 31. The channel element 31 can extend through this opening 41 into the recess 23 and further into the configured channel of the shoe 15. Thus, by reducing friction, forces in the machine direction MD, which extend through the nip 13 and act on the shoe 15 of the belt housing 17 and further act on the pressure shaft 18 via the rear support 25, can be reduced.

The purpose of fig. 1 and 2 is only to illustrate the functional environment associated with the pressure axis. In fig. 1 and 2, for example, the loading oil and lubricating oil are led into the central bore of the pressure shaft 18 and there is a pipe connection downwards there from for lubrication out of the connecting piece 20 and through the flange 19.1 to the shoe 15. The loading line is located below the recess, from which there starts a pipe connection to the loading cylinder. It is also possible to arrange, for example, lubrication lines and loading lines on the shoe. The medium is then guided from the end to the web 20 via the pipe and at least to the loading cylinder via the flange 19.1. Therefore, the shoe rolls and the long nip press shown in fig. 1 and 2 should not be considered as limiting the object of application of the pressure shaft 18 according to the present invention.

Fig. 3 and 4 show examples of the pressure shaft 18 of the shoe roller 11 in cross-section. It should be noted here that the pressure shaft 18 shown in fig. 1 and 2 does not have to be the same as that shown in fig. 3 and 4, but only the pressure shaft 18 according to the invention is shown on the application object, i.e. at the long nip press 10 and at its shoe roll 11.

In fig. 3 a pressure shaft 18' according to the prior art is shown, in fig. 4 a pressure shaft 18 according to the invention is shown again. In both cases, the pressure shafts 18', 18 are adapted to an I-shaped profile in the loading region as regards their basic cross section. The pressure shafts 18', 18 thus comprise a first flange 19.1, a second flange 19.2 and a narrow web between them connecting the flanges 19.1, 19.2 to each other, which web is also generally referred to simply as a web 20. The flanges 19.1, 19.2 stiffen the pressure shafts 18', 18 and allow the pressure shafts 18', 18 to achieve a higher load-carrying capacity. The flange 19.1, 19.2 is divided into two flange portions 21.1, 21.2 in the pressure shafts 18', 18 on their sides in the machine direction MD or in the circumferential direction of the shoe roller 11. Here too, flange portions 21.1, 21.2 are arranged on both sides of the web 20 in the circumferential direction of the shoe roller 11.

In fig. 3 and 4, a recess 23 can also be seen, in which a loading element 16 is arranged in order to load the elongated medium-lubricated shoe 15 forming the nip 13 against the counter roll. The recess 23 is located on the pressure shaft 18', 18 on the side of the first flange, i.e. the flange 19.1 on the side of the shoe 15. A continuation (Fortsetzung) of the middle portion of the web 20, which is shown in fig. 4 in dashed lines and is marked 46, remains between the flange portions 21.1, 21.2 of the first flange, i.e. the flange 19.1 on the shoe 15 side. Thus, the recess 23 is part of the two flange portions 21.1, 21.2 and the intermediate portion 46 of the connecting piece 20 divides the first flange 19.1 into flange portions 21.1, 21.2. In other words, the intermediate line 46 of the connecting piece 20 defines the flange portions 21.1, 21.2 as the portion of the recess 23 which continues from the intermediate portion 46 of the connecting piece 20 towards the inlet side a belongs to the first flange portion 21.1 and the corresponding portion of the recess 23 towards the outlet side B belongs to the second flange portion 21.2.

The recess 23 may be continuous and extend over the major length of the loading area of the roller 11. The length of the loading zone of the roller 11 may be, for example, at most as long as the shoe 15. An I-shaped profile according to the invention is realized in the middle part of the pressure shaft 18, which may be referred to as the basic cross section of the pressure shaft 18. In this case, in the edge region of the pressure shaft 18, there are regions of the outermost 1 to 3 charge cylinders of the shoe 15, for example, wherein in the direction of the pin shape there is a transition region of the cross section of the I-shaped profile in the pressure shaft 18. This can be seen in fig. 1 and 2. Alternatively, the recess may also be a discrete machining performed on the pressure shaft, on the bottom of the loading cylinder.

The shoe 15 can be said to have an inlet side a and an outlet side B. The inlet side a and the outlet side B are now defined by the direction of rotation of the mantle 17 to be arranged on the shoe roll 11 (arrows in fig. 3 and 4). The cover 17 contacts the shoe 15 from the inlet side a and leaves the shoe 15 from the outlet side B or discards it. On the outlet side B, the shoe 15 may be supported on a rear support 25, which receives forces in the machine direction MD. The rear support 25 may be formed, for example, integrally on the first flange 19.1, on its outlet side B or flange portion 21.2, and thus be part of the casting of the flange 19.1. On the other hand, the rear support 25 may also be formed by one or more support blocks fastened to the flange portion 21.1, which is shown in fig. 4 by a dash-dot line on the rear support 25. On the second flange portion 21.2, a depression 47 may be arranged on the outlet side B of the shoe 15 in the longitudinal direction of the pressure shaft 18', 18 for configuring the function of the rear support.

The collector 27 shown in fig. 2 for collecting the medium from the shoe roller 11 may be fitted before the recess 23 and thus also before the inlet side a of the shoe 15 fitted to the pressure shaft 18. In other words, the collector 27 is adapted to the flange portion 21.1 of the inlet side a of the first flange 19.1. The shoe roll 11 may be a roll in the upper position of the nip 13 or may be a roll in the lower position. In both positions, the medium fed between the shoe 15 and the housing 17 and circulated there from hitsAt the inlet side a of the shoe, here the medium is collected in a collector 27 arranged before the inlet side.

The pressure axes 18, 18' have an inertial axis structure XYZ. In the inertia axes of the inertia axis structure, the two inertia axes Z and Y are arranged perpendicularly relative to each other in a cross-sectional plane 22 of the pressure axis 18. On the pressure axis 18 'according to the prior art or according to fig. 3, the inertia axis Z is parallel to the web 20 of the pressure axis 18', i.e. to the nip force F directed towards the shoe 15. The inertia axes Y lie in the same plane again, but are perpendicular relative to the inertia axis Z. The inertia axis Y is here represented as a web 22. A third of the axes of inertia, or X, is in turn arranged in the longitudinal direction of the pressure axis 18' (fig. 1) and in a transverse plane 22 of the pressure axis 18 perpendicularly to the web 20 parallel to the axis Z and to the axis of inertia Y directed away from the web 20.

In the prior art pressure shaft 18 'shown in fig. 3, the inertia axis Z of the inertia axis structure XYZ is parallel to the web 22 and thus also to the nip force F directed towards the shoe 15 or even slightly towards the outlet side B of the first flange 19.1 or turned in the direction of the flange portion 21.2 in the cross-sectional plane 22 of the pressure shaft 18'. This is because there is symmetry in the cross-section plane 22 parallel to the web 20 or the axis of inertia Z. On the pressure shaft 18 according to the invention shown in fig. 4, the first flange 19.1 is adapted in cross section such that the two axes of inertia Y, Z of the pressure shaft 18 are parallel to the cross-sectional plane 22, the axis of inertia Z vanishing in the direction of the inlet side a of the first flange 19.1. Thus, the associated inertial axis Z is inclined in the direction of the flange portion 21.1 of the first flange 19.1. Meanwhile, the inertial axis structure XYZ rotates as follows: i.e. the inertia axis Y is no longer perpendicular to the web 20 and thus also to the nip force F, but rotates relative to the second flange portion 21.2 of the first flange 19.1. In fig. 4, the inertial axes Z of rotation according to the invention are shown only by way of example for the purpose of illustrating the invention. The cross-sectional score of the pressure shaft 18 is also not shown in fig. 4, as it is for example in fig. 3.

It can also be seen in fig. 4 that the pressure shaft 18 is asymmetric with respect to the first flange 19.1 when viewed parallel to the connecting piece 20. The flange portions 21.1, 21.2 of the first flange 19.1 are thus different from each other in terms of cross-sectional shape. This asymmetry is caused by the mutually different cross-sectional shapes of the flange portions 21.1, 21.2, wherein the material in the pressure shaft 18 is kept in the correct position.

The rotation of the inertial axis structure XYZ of the pressure shaft 18 according to the invention can be defined in a number of different ways, for example with respect to the arrangement of the material on the first flange 19.1 of the pressure shaft 18, i.e. on the shoe 15 side. According to one form of application, the flange portion 21.1 of the inlet side a of the first flange 19.1 comprises an end edge 35.1 and a face 14 on the mantle 17 side of the shoe roll 11. According to one form of application, this face 14 can be formed on one side of the housing 17 by a parallel plane 38 and an inclined plane 26 present between the end edge 35.1 and the plane 38 with respect to the recess 23. The end edges 35.1, 35.2 of the first flange 19.1 are the outermost edges of the first flange 19.1 in the circumferential direction of the pressure shaft 18. The parallel plane 38 is again the plane of the flange portion 21.1 beside the recess 23 with respect to the recess 23.

According to one embodiment, the surface 14 on the outer jacket 17 side of the flange portion 21.1 on the inlet side a is adapted in the cross-sectional plane 22 of the pressure shaft 18 to a lower plane than the surface 33 on the web 20 side of the flange portion 21.2 on the outlet side B. In this illustrated application, this will be achieved, for example, in connection with the end edges 35.1, 35.2 of the flange portions 21.2, 21.2. In particular in the illustrated application form, the edge 28 on the end edge 35.1 side of the inclined plane 26 in the flange portion 21.1 of the inlet side a of the first flange is adapted on the cross-sectional plane 22 of the pressure shaft 18 on a lower plane than the lower face 33 on the web 20 side of the flange portion 21.2 of the outlet side B. Therefore, the flange portion 21.2 of the outlet side B has a significantly smaller thickness than the flange portion 21.1 of the inlet side a. The flange portions 21.1, 21.2 may be arranged on the same plane, as regards size and overall, on one side of the recess 23, as seen in a basic cross-section. The flange portion 21.1 of the inlet side a extends further from the opposite side, i.e. from the web 20 side, in the direction of the second flange 19.2. According to one form of application, it may be, for example, as thick as the material of the end edge 35.1.

Furthermore, in the illustrated application form, the face 36 of the flange portion 21.1 belonging to the inlet side a, which is located externally in relation to the recess 23 in the cross-sectional plane, which face is arranged for the shoe 15, is adapted on the side of the web 20 to form the bottom surface of the cross-section of the first flange 19.1. More generally, at least for a part of the faces 36, i.e. the faces 36 between the lower edge 34 of the end edge 35.1 and the web 20, the distance D1 of the faces 36 on the web 20 side of the flange portion 21.1 of the inlet side a from the second flange 19.2 is smaller than the distance D2 of the faces 33 on the web 20 side of the flange portion 21.2 of the outlet side B from the second flange 19.2. The difference in the distances D2, D1 can be, for example, at least half the thickness of the flange portion 21.2 on the outlet side, at least for a part of the face 36. In the illustrated application form, the face 36 engages directly on the web 20 at the root 48 of the web 20 with slight relief (Entlastung) 42.1. That is, the flange portion 21.1 of the inlet side a now has no obvious recess 49, which recess 49 is present in the pressure shaft 18' according to the prior art shown in fig. 3, outside the recess 23 arranged for the shoe 15 in the cross-sectional plane.

According to one form of application, the pressure shaft 18 is adapted to extend from the web 20 from the side of the first flange 19.1 in such a way that: i.e. the first flange 19.1 extends out of the web 20 with slight relief 42.1 onto the flange portion 21.1 of the inlet side a. Thereby resulting in a deviation between the flange portions 21.1 and 21.2. The surface 36 on the web 20 side of the flange portion 21.1 of the inlet side a immediately following the relief 42.1 is mainly planar. It thus continues in planar form as described above up to the end edge 35.1 of the inlet side a. In the flange portion 21.2 of the outlet side B there is in turn a relief area 42.2. In the illustrated application form, this undulating region 42.2 is located in a functional region of the depression 47 and the rear support 25 of the shoe 15. Furthermore, the lower face 33 of the connecting piece 20 can be adapted in this region by the flange portion 21.2 to follow a curved face, straightened against the end edge 35.2. Here, the lower face 33 on the web 20 side of the flange portion 21.2 of the outlet side B rises to a higher level than the face 36 on the web 20 side of the flange portion 21.1 of the inlet side a, and an asymmetry of the flange 19.1 and a narrower cross section of the flange portion 21.2 of the outlet side B are established. Even if the function of the rear support 25 has been formed by a part fastened to the flange part 21.2, the narrowness of the cross section of the flange part 21.2 of the outlet side B is still to be emphasized further, which in any case does not significantly affect the stiffness of the pressure shaft 18.

More generally, on the pressure shaft 18 according to the invention, the area of the cross section of the flange portions 21.1, 21.2 is varied in such a way that: that is, the area of the cross section of the flange portion 21.2 of the outlet side B decreases, while the area of the cross section of the flange portion 21.1 of the inlet side a increases. In other words, the first flange 19.1 on the shoe 15 side has become different from the first flange 19.1 according to the prior art, for example has changed compared to the symmetry shown in fig. 3.

It can also be seen in fig. 4 that in the illustrated application form, the surface 33 on the web 20 side of the outlet side B is adapted to be at a distance of less than 40mm from the bottom of the recess 23 in association with the end edge 35.2 of the flange portion. The difference in the flange portions 21.1, 21.2 is emphasized again that the portion on the side of the outer envelope 17 of the end edge 35.1 of the flange portion 21.1 is again arranged at a distance of less than 50mm from the bottom of the recess 23 on the inlet side a or on the edge 28 on the side of the inclined plane 26. Wherein the outlet side B is still closer to the bottom of the recess 23. This also describes in part the narrowness of the flange portion 21.2 of the outlet side B.

The flange portion 21.1 of the inlet side a comprises an end edge 35.1 and a face 14 on the mantle 17 side of the shoe roll 11. The face 14 on one side of the cover 17 has a parallel plane 38 with respect to the recess 23 and an inclined plane 26 between the plane 38 and the end edge 35.1. In the illustrated application form, the inclined plane 26 is still adapted to be formed by at least two planes 50.1, 50.2 or one curved face, when the area of the cross section of the flange 21.1 should be maximized.

With one or more of the above-mentioned cross-sectional features, the flange portion 21.1 of the inlet side a of the first flange 19.1 can be reinforced such that the flange portion 21.1 remains more straight under the influence of the pure pressure area than the pressure shaft 18' according to the prior art. Furthermore, the material on the flange portion 21.1 of the inlet side a of the first flange and thus the material thickness is further away from the midpoint 51 of the pressure shaft 18, which contributes to the rigidity of the structure, by means of one or more cross-sectional features of the first flange 19.1 on the side of the recess 23 of the pressure shaft 18. By means of the invention, the pressure shaft 18 according to the invention is bent in the direction of the inlet of the nip 13 under the nip force F (e.g. 1400 kN/m). Accordingly, in the known pressure shaft 18', the pressure shaft is bent in the direction of the outlet side of the nip in the corresponding case. If there is a force in the machine direction MD (e.g. 11 kN/m) in addition to the nip force F, the pressure shaft 18 according to the invention is surprisingly almost straight. In the symmetrical pressure axis profile according to the prior art, the limit value for MD bending is exceeded again. Further, since the shoe 15 is bent with the pressure shaft 18, a problem arises in the nip 13. In the pressure shaft 18 according to the invention, the nip 13 and the shoe 15 are more straight (MD) over the entire length of the pressure shaft and also over the width of the pressure shaft.

Since the material thickness of the flange portion 21.1 of the inlet side a of the flange 19.1 is in many ways greater than the flange portion 21.2 of the outlet side B of the flange 19.1, the inertial axis Z of the inertial axis structure XYZ of the pressure shaft 18 rotates in the direction of the flange portion 21.1 of the inlet side a of the pressure shaft 18. Thus, here, ternaryThe inertial axis structure XYZ rotates in the longitudinal direction of the pressure axis 18, i.e. about the inertial axis X. Taking into account the improved stiffness characteristics of the pressure shaft 18, a better directional loading, i.e. nip forces F and bending in the machine direction MD, will thus advantageously be achieved. When the forces concerned are directed towards the shoe roller 11 during operation, the shoe roller 11 will be substantially more straight, i.e. will extend centrally or slightly obliquely in the direction of the flange portion 21.2 of the outlet side B with respect to the recess 23 for the shoe 15 arranged on the first flange 19.1, than if the axis of inertia Z of the axis of inertia structure XYZ is parallel to the web 20.

According to the invention, the pressure shaft 18 is adapted as part of the shoe roll 11. In addition to the parts listed above, the shoe roll 11 also comprises, for example, a collector 27 before the depression 23 of the pressure shaft 18 and thus arranged on the pressure shaft 18 before the shoe 15, which is equipped with one or more pipe connections 29 for collecting medium from the shoe roll 11 and one or more discharge channels 30 connected to the pipe connections 29 for the medium collected by the collector 27. The pressure shaft 18 and the collector 27 are arranged in the housing 17 to be fitted to the shoe roller 11 together with the discharge channel 30. Furthermore, the outlet duct 30 is arranged in connection with the solution according to the invention so as to surround the flange portion 21.1, whereby no through-penetration (Durchf u hrungen) for the outlet duct 30 has to be drilled in the flange 19.1.

In addition to the press shaft 18 and the shoe roll 11, the invention also relates to a long nip press 10 comprising at least one shoe roll 11 according to the invention, which is equipped with a press shaft 18 according to the invention. The invention can be applied to a fiber web machine comprising at least one press section with at least one long nip press 10 equipped with at least one shoe roll 11 according to the invention.

It should be understood that the foregoing description and associated drawings are only illustrative of the present invention. Accordingly, the invention is not limited by the embodiments described above or defined in the claims, but it will be obvious to a person skilled in the art that many different variants and alternatives of the invention are possible within the scope of the idea according to the invention as defined in the appended claims.

Claims (15)

1. A pressure shaft for a shoe roll having an I-shaped profile in base cross section and comprising:

a first flange (19.1) and a second flange (19.2) and a connecting piece (20) between them,

-a recess (23) adapted to one side of the first flange (19.1), a loading element (16) for the shoe (15) adapted to the pressure shaft (18),

a flange portion (21.1) of the inlet side (A) of the first flange (19.1),

-a flange portion (21.2) of the outlet side (B) of the first flange (19.1) being arranged for a rear support (25) of the shoe (15),

and the pressure shaft (18) has an inertial shaft structure (XYZ) with two inertial axes (Y, Z) parallel to a cross-sectional plane (22) of the pressure shaft (18),

it is characterized in that the method comprises the steps of,

the cross section of the first flange (19.1) is adapted such that one of two inertia axes (Y, Z) of the inertia axis structure (XYZ) of the pressure axis (18) parallel to the cross-section plane (22) is adapted to be inclined in the direction of the inlet side (a) of the first flange (19.1).

2. The pressure shaft according to claim 1, characterized in that the flange portion (21.1) of the inlet side (a) comprises an end edge (35.1) and a face (14) on the mantle (17) side of the shoe roll (11), and in that in a cross-sectional plane (22) of the pressure shaft (18) the face (14) on the mantle (17) side of the flange portion (21.1) of the inlet side (a) is adapted at least in sections at a lower height than a face (33) on the web (20) side of the flange portion (21.2) of the outlet side (B).

3. A pressure shaft as claimed in claim 2, characterized in that, on the end edges (35.1, 35.2) of the flange portions (21.1, 21.2), on a cross-sectional plane (22) of the pressure shaft (18), a face (14) of the flange portion (21.1) side of the housing (17) of the inlet side (a) is adapted to be at a lower level than a face (33) on the web (20) side of the flange portion (21.2) of the outlet side (B).

4. A pressure shaft according to any one of claims 1-3, characterized in that the flange portion (21.1) of the inlet side (a) comprises a face (36) on the side of the connection piece (20) adapted to form the lowest plane of the cross section of the first flange (19.1).

5. A pressure shaft according to any one of claims 1 to 4, characterized in that the distance (D1) of the face (36) of the flange portion (21.1) of the inlet side (a) on the web (20) side from the second flange (19.2) is at least for a part smaller than the distance (D2) of the face (33) of the flange portion (21.2) of the outlet side (B) on the web (20) side from the second flange (19.2).

6. A pressure shaft according to any one of claims 1-5, characterized in that, at least for a part of the faces (36), the distance (D1) of the face (36) of the flange part (21.1) on the web (20) side from the second flange (19.2) of the inlet side (a) is smaller than the corresponding distance (D2) of the face (33) of the flange part (21.2) on the web (20) side of the outlet side (B) by at least half the thickness of the flange part (21.2) of the outlet side (B).

7. The pressure shaft according to any one of claims 1 to 6, characterized in that the pressure shaft (18) is adapted to extend from the connecting piece (20) laterally of the first flange (19.1) as follows:

-the first flange (19.1) extends out of the connecting piece (20) with slight relief (42.1) to a flange portion (21.1) of the inlet side (a),

the face (36) on the web (20) side of the flange portion (21.1) of the inlet side (A) immediately following the relief is substantially planar,

-the web (20) side face (33) of the flange portion (21.1) of the outlet side (B) is adapted to follow the curved face to straighten in the direction of the end edge (35.2).

8. A pressure shaft as claimed in any one of claims 1 to 7,

-the face (33) on the connecting piece (20) side of the flange portion (21.2) of the outlet side (B) is adapted in association with the end edge (35.2) of the flange portion (21.2) to a distance of less than 40mm from the bottom of the recess (23),

-the edge (28) of the flange portion (21.1) of the inlet side (a) on the side of the inclined plane (26) of the end edge (35.1) is adapted at a distance of less than 50mm from the bottom of the recess (23).

9. A pressure shaft according to any one of claims 1-8, characterized in that the first flange (19.1) is adapted to be divided into flange portions (21.1, 21.2) at a centre line (46) of the connecting piece (20).

10. The pressure shaft according to any one of claims 1 to 9, characterized in that the flange portion (21.1) of the inlet side (a) comprises end edges (35.1), planes (38) parallel with respect to the recesses (23) and inclined planes (26) therebetween, and in that the inclined planes (26) are adapted to be formed by at least two faces (50.1, 50.2) or curved faces to maximize the cross-sectional area of the flange portion (21.1).

11. The pressure shaft according to any one of claims 1 to 10, characterized in that the first flange (19.1) of the pressure shaft (18) has no through-penetration with respect to the discharge channel (30) of a collector (27) adapted to the flange portion (21.1) of the inlet side (a) of the first flange (19.1).

12. The pressure shaft according to any one of claims 1 to 11, characterized in that the face (14) of the shell (17) side of the shoe roll (11) comprises a plane (38) parallel with respect to the recess (23) and an inclined plane (26) between the plane (38) and the end edge (35.1).

13. A shoe roll comprising:

-a pressure shaft (18, 18') having an I-shaped profile base cross section and adapted to

A first flange (19.1) and a second flange (19.2) and a connecting piece (20) between them,

-a recess (23) adapted to one side of the first flange (19.1), a loading element (16) for the shoe (15),

a flange portion (21.1) of the inlet side (A) of the first flange (19.1),

-a flange portion (21.2) of the outlet side (B) of the first flange (19.1) being arranged for a rear support (25) of the shoe (15),

and the pressure shaft (18) has an inertial shaft structure (XYZ) with two inertial shafts (Y, Z) arranged parallel to a cross-sectional plane (22) of the pressure shaft (18),

said shoe (15) being fitted on said pressure shaft (18, 18') on a recess (23) fitted on one side of said first flange (19.1),

-the loading element (16) of the shoe (15) is adapted to load the shoe (15) with respect to the counter roller (12),

the housing (17) is arranged to rotate about the pressure axis (18) and is adapted, formed by a belt loop,

-characterized in that the pressure shaft (18) of the shoe roll (11) is according to any one of claims 1 to 12.

14. Shoe roll according to claim 13, characterized in that the shoe roll (11) comprises a collector (27) adapted to a flange portion (21.1) of the inlet side (a) of the first flange (19.1), from which flange portion a discharge channel (30) is arranged to surround the flange portion (21.1).

15. A long nip press comprising at least one shoe roll (11) and a counter roll (12) arranged in connection with the shoe roll, characterized in that the shoe roll (11) is a shoe roll according to claim 13 or 14.