EP3802951B1 - Roller for a machine for producing and/or processing a paper, cardboard, or tissue web, and method for operating the roller - Google Patents

Description

The invention relates to a roller for a machine for producing or processing a fibrous web according to the preamble of claim 1, as well as a method for operating such a roller.

Sealing devices in vacuumed or blown rollers for paper, cardboard or tissue machines must reliably seal the overpressure or underpressure zone against the environment in which normal pressure prevails. To seal the overpressure or underpressure zone, the sealing surface of each sealing strip of the sealing device is placed against the inside of the rotating roller shell. In order to reduce wear on the sealing strip caused by friction between the shell surface and the sealing surface, attempts are made to introduce a lubricant between the sealing surface and the inside. This is usually done with spray pipes that are arranged in front of the first sealing strip of the overpressure or underpressure zone in the direction of rotation of the roller. The lubricant is applied to the inside of the roller shell and transported by the shell to the individual sealing strips as it rotates, which means that the lubricant supply from sealing strip to sealing strip decreases in the direction of rotation. In order to supply the sealing strips following in the direction of rotation with sufficient lubricant, a large amount of lubricant must be used, which, however, only benefits the actual lubrication of the sealing strips to a small extent and otherwise contributes to the undesirable re-moistening of the fibrous web.

To solve this problem, the EP2885457 as well as the EP3022356 to direct the lubricant directly to the top of the respective sealing strip, which provides the sealing surface, in order to provide each individual sealing strip with the required A preferred embodiment of this invention further proposes a lubricant channel provided on the top of the roller in the form of a groove-like depression arranged next to the sealing surface and extending in the longitudinal direction of the sealing strip, ie in the cross-machine direction of the roller, if necessary with the aid of a suitable lip. EP2885457 discloses a roller according to the preamble of claim 1.

Regardless of which type of lubrication device is used, it is essential for low-wear operation of such a roller that the sealing surface of the sealing strip is supplied with sufficient lubricant over its entire length, which is often 10m or more. However, for economic reasons, as little lubricant as possible should be used for this lubrication.

For this purpose, it would be desirable to ensure that the lubricant is distributed as evenly as possible over the entire length of the sealing strip.

It is therefore an object of the invention to propose a roller with a sealing device in which a uniform supply of lubricant to the sealing strip is ensured. Furthermore, an object of the invention is to provide a reliable method for operating such a roller using a small amount of lubricant.

The object is completely achieved with regard to the roller by a roller for a machine for producing or processing a fibrous web according to claim 1 and with regard to the method by a method for operating a roller according to claim 14.

Further advantageous embodiments are described in the subclaims.

A roller is proposed for a machine for producing or processing a fibrous web, which comprises a movable roller shell and an overpressure or underpressure zone arranged within the roller shell and which is rotationally fixed compared to the roller shell, as well as a sealing device for sealing the overpressure or underpressure zone from the environment. The sealing device has a sealing strip and a lubricating device by means of which a lubricant can be brought between the inside of the roller shell and the sealing surface of the sealing strip, wherein the lubricating device comprises a plurality of lubricant outlet openings and is connected via several inlet segments to a supply line for supplying lubricant. According to the invention, the roller is characterized in that the supply line comprises an inner section which runs within the roller shell and this inner section has a storage volume of at least 490 cm ³ /m, in particular at least 500 cm ³ /m, in particular of at least 750 cm ³ /m or 1000 cm ³ /m, based on the length of the sealing strip.

An inlet segment is understood to be a line section that is connected to the supply line that supplies the entire lubrication system and directs lubricant to some of the lubricant outlet openings.

Tests by the applicant have surprisingly shown that a uniform lubricant distribution can be achieved with such a supply line for the sealing device. The buffer effect of the comparatively large storage volume of the supply line ensures that all inlet segments are supplied with the same pressure, or that the pressure difference is at least so small that it has no significant influence on the distribution of the lubricant. This represents a significant difference to the rollers known from the prior art. A supply line, usually thin, is fed into the roller from one side, and the inlet segments to the lubrication device branch off from this supply line. This means that in the inlet segments further back in the direction of flow of the lubricant, there is noticeably less pressure, or a smaller amount of lubricant is fed to the lubrication device. This effect is largely avoided by the storage volume in the roller in question.

The size of the storage volume should be at least 490 cm ³ /m, in particular at least 500 cm ³ /m. The value of 490 cm ³ /m or 500 cm ³ /m is sufficient for the lubricant quantities normally used of 0.5 l/m/min to approx. 3 l/m/min. Larger storage volumes of 1000 cm ³ /m, 2000 cm ³ /m or more are advantageous for reasons of evening out the pressure as described above. Due to the relatively tight installation space in some rollers or for economic reasons, it may be sensible to limit the size of the storage volume upwards. For example, it may be advantageous not to provide a storage volume larger than 20,000 cm ³ /m or 10,000 cm ³ /m.

The storage volume in "cm ³ /m" refers to the length of the lubricated sealing strip. The roller can advantageously be designed as a suction roller. In such suction rollers, the roller shell has openings that are usually arranged in a regular pattern. In this way, water can be sucked out of a fibrous web or a covering through the openings in the roller shell using the negative pressure prevailing in the negative pressure zone.

In an advantageous embodiment of the invention, it can be provided that the inner section comprises or consists of a tubular part which extends essentially over the entire length of the sealing strip, wherein this tube has an inner diameter of 25 mm or more, in particular more than 40 mm, preferably 50 mm or more, at least at one point. Such an embodiment is advantageous because it fulfills two properties of the supply line at the same time, namely the distribution of the lubricant over the length the roller or the sealing strip and the provision of the storage volume. In particular, it can advantageously be provided that the pipe has a constant cross-section over more than 50% of its length, in particular over its entire length. A pipe that has an inner diameter of 25mm over its entire length, for example, provides approx. 490 cm ³ /m, i.e. around 500 cm ³ /m of storage volume. In another advantageous embodiment, it can be provided that the pipe tapers continuously over its length. Such an embodiment can be advantageous in particular for long sealing strips of more than 5m, or more than 10m, in order to keep the pressure at the inlet segments located at the back in the direction of flow of the lubricant even more constant.

In preferred embodiments, it can further be provided that the majority of the lubricant outlet openings are evenly distributed over the length of the sealing strip, in particular that the distances between adjacent lubricant outlet openings differ by less than 25% or less than 10%. In addition to the even supply of the inlet segments, such a distribution of the lubricant outlet openings also supports the even distribution of the lubricant over the entire length of the sealing strip.

Advantageously, the distance between two adjacent lubricant outlet openings can be between 20 mm and 200 mm, in particular between 30 mm and 100 mm. In particularly preferred embodiments, the distance between adjacent lubricant outlet openings is between 40 mm and 60 mm.

The lubrication device can be implemented, for example, by guiding the lubricant from the inlet segments to nozzle devices, e.g. fan nozzles, which represent the lubricant outlet openings. The lubricant is lubricated via the nozzles in the direction of the sealing surface to be lubricated.

These nozzle devices are known as lubrication spray pipes and are usually arranged in front of the sealing strip in the direction of rotation of the roller.

However, it can also be advantageous for the lubricating device to be provided entirely or partially in or on the sealing strip, with the lubricant outlet openings in particular being located in the sealing strip. Such sealing strips with an integrated lubricating device are often preferred because the sealing surface can be lubricated with a smaller amount of lubricant.

Furthermore, it can be provided that the inner section is at least partially rigid. The term "rigid" is to be understood in comparison to the inlet segments. Inlet segments are often made entirely or at least partially from plastic hoses. This is particularly useful for sealing strips with an integrated lubrication device, since the inlet segment has to move with the movement of the strip caused by wear. For reasons of stability and easier handling, it can be advantageous if the inner section of the supply line is at least partially made from a rigid material, e.g. in the form of a metal pipe or a plastic pipe.

Sealing devices often have a so-called holder for holding the sealing strip. In a preferred embodiment, it can be provided that the inner section runs at least partially on or in this holder.

In preferred embodiments, it can be provided that all inlet segments have the same length or differ in length by less than 25%. If the lengths of the inlet segments differ too much, there may be a risk that the effect of equalizing the pressure achieved by the invention cannot be fully passed on to the lubricant outlet openings.

Advantageously, the length of the inlet segments can be between 150 mm and 700 mm, in particular between 200 mm and 400 mm.

A very advantageous design is when the inner section of the supply line is mounted on the outside of the suction box of a negative pressure zone. On the one hand, this mounting position is easier to access than inside the suction box. On the other hand, the distance from the inner section of the supply line to the inlets of the sealing strip is usually smaller, so that shorter inlet segments with a length of, for example, 150mm-250mm can be used.

The distance of an inlet segment to a longitudinal end of the sealing strip can preferably be a maximum of 800 mm, in particular a maximum of 600 mm, preferably 400 mm or less.

Alternatively or additionally, it can be provided that the inlet segments are arranged such that their distance from one another in the longitudinal direction of the roller is less than 2 m, in particular less than 1.75 m, preferably 1.5 m or less. In particular, the inlet segments can also be arranged such that the distance between adjacent inlet segments in the longitudinal direction of the roller is the same or differs by only less than 15%, in particular less than 5%.

Furthermore, it can be advantageous if the supply line also has an outer section which runs essentially outside the roller, wherein the outer section with an inner diameter of 25 mm or less, in particular 20 mm or less or 15 mm or less, is guided over an end face into the interior of the roller, where it is connected to the inner section. In particular, the outer section can have a smaller inner diameter than the inner section, in particular also at the connection point of the two sections.

With regard to the method, the object is achieved by a method for operating a roller for a machine for producing or processing a fibrous web, wherein the roller is designed according to one of the previous claims, characterized in that the lubricating device is supplied with less than 2.4 l/min/m, in particular between 0.4 l/min/m and 1.5 l/min/m of lubricant. With such an amount of lubricant, the roller proves to be particularly advantageous according to one of the above-mentioned aspects.

Furthermore, it can be advantageous that the lubricating device is supplied with a first amount of lubricant over a starting period, and after this starting period the lubricating device is supplied with a second amount of lubricant, wherein the first amount of lubricant is greater, in particular more than 25% greater, than the second amount of lubricant - in each case based on l/min/m.

For example, over a start-up period the lubrication device can be supplied with 2.4 l/min/m or more of lubricant, and after this start-up period the lubricant quantity is reduced to less than 2.4 l/min/m, in particular between 0.4 l/min/m and 1.5 l/min/m.

Such a start period can, for example, be at least 30 s, in particular between 30 s and 5 min. Such a start period, which precedes standard operation, can ensure, among other things, that the storage volume is completely filled with lubricant and thus the roller or the lubricating device can develop its full effect.

Water can usually be used as a lubricant, to which additives can be added if necessary. The pressure in the supply line can be, for example, between 2 and 8 bar, in particular 4 bar to 6 bar.

Another idea that can be used in a roller according to one aspect of the invention relates to a sealing device for sealing an overpressure or underpressure zone of a roller for a machine for producing or processing a fibrous web, wherein the sealing device has a sealing strip and a lubricating device by means of which, when used as intended, a lubricant can be brought between the inside of the roller shell and the sealing surface of the sealing strip, and wherein the lubricating device comprises a plurality of lubricant outlet openings and can be connected to a supply line for supplying lubricant. The sealing device is characterized in that the lubricating device can be connected to the supply line via several inlets which are distributed over the length of the sealing strip, the sealing strip has a first and a second longitudinal end and the distance from at least one, preferably both longitudinal ends to an inlet is a maximum of 800 mm, in particular a maximum of 600 mm, preferably 400 mm or less.

As already mentioned, such a sealing device can be used in combination with a supply line which has a storage volume of at least 490 cm ³ /m, in particular at least 500 cm ³ /m. The inlet segments explained above can be connected to the inlets of the sealing device described here.

Such a sealing device can be particularly advantageous for supplying the edges of the sealing strip with sufficient and even lubricant. Over most of the length of the sealing strip, every point can be supplied with lubricant from both the right and the left, since there is at least one inlet on both sides through which lubricant is supplied to the lubricating device. In the edge areas of the sealing strip beyond the first or last inlet, however, the problem arises that these areas are only supplied with lubricant from one side, since there is only an inlet on one side. This can lead to the region of the longitudinal ends of the sealing strip not being be supplied with sufficient lubricant, especially with less lubricant than the middle area of the sealing strip.

Advantageous designs of such a sealing strip are described below

It can thus advantageously be provided that the inlets are arranged such that their distance from one another in the longitudinal direction of the roller is less than 2 m, in particular less than 1.75 m, preferably 1.5 m or less. In particular, the inlets can also be arranged such that the distance between adjacent inlets in the longitudinal direction of the roller is the same or differs by only less than 15%, in particular less than 5%.

Preferably, the lubricating device can be provided entirely or partially in or on the sealing strip, wherein in particular the lubricant outlet openings can be in the sealing strip.

• Figur 1 zeigt einen Ausschnitt einer Walze gemäß einem Aspekt der Erfindung
• Figur 2 zeigt einen Ausschnitt einer Walze gemäß einem weiteren Aspekt der Erfindung
• Figur 3 zeigt einen Ausschnitt einer Walze gemäß einem weiteren Aspekt der Erfindung
• Figur 4 zeigt einen Ausschnitt einer Walze gemäß einem weiteren Aspekt der Erfindung

The invention is further explained below with reference to schematic drawings, whereby the invention is not limited to these embodiments.

• Figure 1 shows a section of a roller according to one aspect of the invention
• Figure 2 shows a section of a roller according to another aspect of the invention
• Figure 3 shows a section of a roller according to another aspect of the invention
• Figure 4 shows a section of a roller according to another aspect of the invention

Figure 1 shows a roller 1 with a roller shell 11 and a front side 12. Such a roller can be, for example, a suction roller 1. A sealing device 2 is provided inside the roller 1. This comprises a sealing strip 3 which is arranged in a sealing strip holder 3a, as well as a lubricating device 4. The Figure 1 The lubricating device 4 shown is located largely in the sealing strip 3. A plurality of lubricant outlet openings 5 are arranged next to one another. These openings 5 are positioned such that escaping lubricant gets between the sealing surface of the sealing strip 3 and the roller shell 11. To supply the lubricating device 4 with lubricant, e.g. with lubricating water, a supply line 6 is provided which comprises an inner section 7 which runs inside the roller shell 11 and has a storage volume of at least 490 cm ³ /m , in particular at least 500 cm ³ /m , preferably of at least 2000 cm ³ /m , based on the length of the sealing strip, as well as an outer section 8. The lubricating device 4 is connected to the inner section 7 of the supply line 6 at a plurality of inlets 10, 10a via a plurality of inlet segments 9, 9a. In advantageous embodiments, the distances between two adjacent inlet segments 9, 9a and/or two adjacent inlets 10, 10a can each be the same. Alternatively or additionally, it can be provided that the inlet segments 9, 9a are arranged such that their distance from one another in the longitudinal direction of the roller 1 is less than 2m, in particular less than 1.75m, preferably 1.5m or less. The distance of an inlet segment 9a or an inlet 10a to a longitudinal end of the sealing strip 3 can preferably be a maximum of 800mm, in particular a maximum of 600mm, preferably 400mm or less. The length of the inlet segments can advantageously be between 150mm and 700mm, in particular between 200mm and 400mm. A very advantageous design is when the inner section 7 is mounted on the outside of the suction box of a negative pressure zone. On the one hand, this mounting position is easier to access than inside the suction box. On the other hand, the distance from the inner section 7 of the supply line to the inlets 10, 10a of the sealing strip is usually smaller, so that shorter inlet segments 9, 9a with a length of, for example, 150mm-250mm can be used.

The inner section 7 of the supply line consists of Figure 1 from a tubular part. This pipe is advantageously made of a material (e.g. metal or plastic) that is more rigid than the inlet segments 9, 9a. For example, pipes with inner diameters of 25mm (corresponds to a storage volume of approx. 500 cm ³ /m), 40mm or 50mm (corresponds to a storage volume of approx. 2000 cm ³ /m) can be used. The inlet segments 9, 9a can be designed as hose segments, for example.

Figure 2 differs from Figure 1 in that the inner section 7 consists of a tube 7 which tapers continuously over its length.

Figure 3 shows a sealing strip 3 in a holder 3a, which is pressed against the inside of the roller shell 11 of the roller 1 by means of a pressure hose 13. Such use of a pressure hose for pressing against a moving surface such as a roller shell is a common measure known to the person skilled in the art. In contrast to the Figure 1 and 2 shown versions is in Figure 3 the lubricating device 4 is not integrated in the sealing strip. Lubrication is achieved by means of a number of spray nozzles, which provide the outlet openings 5. The spray nozzles are connected to the inner section 7 of the supply line via inlet segments 9.

Another advantageous feature that Figure 3 is implemented together with the spray nozzles, but is also possible in combination with a lubricating device 4 integrated in the sealing strip 3, consists in that the inner section 7 of the supply line runs at least partially on or in the sealing strip holder 3a. This inner section 7 provides the storage volume of at least 490 cm ³ /m, in particular at least 500 cm ³ /m, and can, for example, have the shape of a cylinder or a tapering cylinder.

In Figure 4 essential components of the invention are shown schematically once again. In a sealing strip 3 with integrated sealing device, the lubricant outlet openings 5 are supplied with lubricant via inlets 10, 10a. The inlets 10, 10a are connected to the inner section 7 of the supply line via inlet segments 9, 9a. The inner section 7 is again designed as a pipe, which also provides the storage volume. The distances from the long end of the sealing strip 3 to the first inlet 10a, or to the first inlet segment 9a, are designated d1 and d5, respectively, while the distances between adjacent inlets 10, 10a or adjacent inlet segments 9, 9a are designated d2, d3, d4. The number of 4 inlets is exemplary. More or fewer inlets/inlet segments may well be provided.

The following table shows some advantageous distances between the inlet segments or inlets. Example No.- d ₁ d ₂ d ₃ d ₄ d ₅ #1 400mm 1360mm 1360mm 1360mm 400mm #2 640mm 1200mm 1200mm 1200mm 640mm #3 540mm 1250mm 1300mm 1250mm 540mm

As can be seen in , the 'inner' distances d2-d4 can be the same or differ by a few millimetres. This can be due to the installation situation, for example.

list of reference symbols

1

roller

2

sealing device

3

sealing strip

3a

holder

4

lubrication device

5

lubricant outlet openings

6

supply line

7

inner section

8

outer section

9, 9a

inlet segment

10,10a

inlet

11

roller shell

12

front side

13

pressure hose

Claims (15)

1. Roll (1) for a machine for producing or processing a fibrous web, comprising a movable roll shell (11) and a positive or negative pressure zone which is arranged within the roll shell (11) and is fixed against rotation relative to the roll shell, and a sealing device (2) for sealing off the positive or negative pressure zone with respect to the surroundings, wherein the sealing device (2) has a sealing strip (3) and a lubricating device (4), by means of which a lubricant can be introduced between the inside of the roll shell (11) and the sealing surface of the sealing strip (3), wherein the lubricating device (4) comprises a plurality of lubricant outlet openings (5) and is connected via multiple inlet segments (9, 9a) to a supply line (6) for the supply with lubricant, wherein the supply line (6) comprises an inner section (7) which extends within the roll shell (11), characterized in that this inner section (7) has a storage volume of at least 490 cm³/m, in particular at least 2000 cm³/m, based on the length of the sealing strip (3).
2. Roll (1) according to Claim 1, characterized in that the inner section (7) comprises a pipe-shaped part or consists thereof, which extends substantially over the entire length of the sealing strip (3), wherein this pipe has an internal diameter of 25 mm or more at at least one point, in particular more than 40 mm, preferably 50 mm or more.
3. Roll (1) according to Claim 2, characterized in that the pipe has a constant cross section over more than 50% of its length, in particular over its entire length.
4. Roll (1) according to Claim 2, characterized in that the pipe tapers continuously over its length.
5. Roll (1) according to one of the preceding claims, characterized in that the plurality of lubricant outlet openings are distributed uniformly over the length of the sealing strip, in particular in that the spacings of adj acent lubricant outlet openings differ by less than 25%.
6. Roll (1) according to one of the preceding claims, characterized in that the lubricating device (4) is provided wholly or partly in or on the sealing strip, wherein in particular the lubricant outlet openings (5) can be in the sealing strip (3).
7. Roll (1) according to one of the preceding claims, characterized in that the inner section (7) is designed to be at least partly more rigid than the inlet segments (9, 9a).
8. Roll (1) according to one of the preceding claims, characterized in that the sealing device (2) comprises a holder (3a) for holding the sealing strip (3), and the inner section (7) extends at least partly on or in this holder (3a).
9. Roll (1) according to one of the preceding claims, characterized in that all the inlet segments (9, 9a) have the same length or differ by less than 25% in their length.
10. Roll (1) according to one of the preceding claims, characterized in that the length of the inlet segments (9, 9a) is between 150 mm and 700 mm, in particular between 200 mm and 400 mm.
11. Roll (1) according to one of the preceding claims, characterized in that the supply line (6) additionally has an outer section (8), which extends substantially outside the roll (1), wherein the outer section (8), having an internal diameter of 25 mm or less, in particular 20 mm or less or 15 mm or less, is guided via an end face (12) into the interior of the roll (1), where it is connected to the inner section (7).
12. Roll (1) according to one of the preceding claims, characterized in that the inlet segments (9, 9a) are arranged such that the spacing of adjacent inlet segments (9, 9a) from one another in the longitudinal direction of the roll (1) is equal or differs only by less than 15%, in particular less than 5%.
13. Roll (1) according to one of the preceding claims, characterized in that the inlet segments (9, 9a) are arranged such that their spacing from one another in the longitudinal direction of the roll (1) is less than 2 m, in particular less than 1.75 m, preferably 1.5 m or less.
14. Method for operating a roll (1) for a machine for producing or processing a fibrous web, wherein the roll (1) is designed according to one of the preceding claims, wherein the lubricating device is supplied with less than 2.4 l/min/m, in particular between 0.4 l/min/m and 1.5 l/min/m, of lubricant.
15. Method according to Claim 14, wherein over a starting time period, the lubricating device (4) is supplied with a first quantity of lubricant and, after this starting time period, the lubricating device (4) is supplied with a second quantity of lubricant, wherein the first quantity of lubricant is greater, in particular more than 25% greater, than the second quantity of lubricant.

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