EP1862588B1 - Press roll - Google Patents

Abstract

In a pressing roller for a fibrous sheet processing machine comprising a rotating roller casing (1), supported on supporting element(s) (3) of a stationary carrier (2), the bearing surface of the supporting element (contacting the the roller casing interior) being lubricated, at least a section of the bearing surface and/or the roller casing interior surface includes micropockets (4). An independent claim is included for the production of the micropockets (4) as above, by incorporation into the surface using a laser or etching procedure.

Description

The invention relates to a press roll of a machine for producing and / or finishing a paper, board, tissue or another fibrous web with a rotating roll shell, which is supported on at least one support element of a stationary support, wherein with the inside of the roll shell in Contact coming tread of the support element is lubricated.

The lubrication of the contact surfaces is hydrostatic and / or hydrodynamic. If the oil supply fails in these press rolls, the emergency running properties should usually be ensured by an appropriate choice of material.

In particular, this is possible with a high lead content in the contact surfaces, which makes this, however, relatively prone to damage due to softness in the form of scoring because of the softness.

The friction between the running surfaces and the inside of the roll mantle requires a high drive power, in particular in the case of very wide paper machines.

From the DE 4202731 A1 and the EP 1394319 A1 It is known that micro oil pockets are provided in the surface of the inside of the roll shell. The inclusion of lubricant in these pockets leads to better sliding properties.

The object of the invention is therefore to improve the lubrication and make it safer.

According to the invention, the object has been achieved in that the running surface, the so-called webs of the support element, has at least in one section micro-pockets.

About the on the inside of the roll shell when starting the press roll applying lubricant film it comes to filling the micro pockets. These micro-pockets remain filled during operation and thus already somewhat reduce the friction between the tread and the inside.

If there is a failure of the lubricant supply, so the present in the micro-pockets lubricant over a sufficient time for shutdown ensures that it is secured between the tread and the inside of the roll shell at least until the standstill of the roll shell, the lubricant supply.

During operation, the running surface of the support element is usually and / or predominantly hydrostatically lubricated. This is advantageously supported by the fact that the running surface delimits at least one pressure chamber open towards the inside of the roll shell and filled with pressure and lubricant, preferably oil. The lubricant is dragged during the rotation of the roll shell in a small but sufficient extent from the pressure chamber into the gap between the tread and the inside. In this way, it also comes to the formation of a lubricating film on the inside of the roll shell.

To ensure this, the micro-pockets should have a depth between 0.1 μm and 500 μm, preferably between 5 μm and 15 μm.

This ensures the presence of sufficient lubricant in the event of lubricant supply failure.

It is also advantageous in the interest of low friction, if the sections with the micro pockets have an open area of less than 60%, preferably between 10 and 30%.

In order not to increase the friction between the tread and the inside due to wear, it is advantageous if the inside of the roll shell at least in a portion, preferably in the areas covered by the tread, coated with a wear-resistant layer.

To simplify and enable extensive use of the roll mantle, it is advantageous if the entire inside of the roll mantle is coated with a wear-resistant layer.

In the interest of the lowest possible production costs, the micro-pockets by means of suitable manufacturing processes such. B. forming process, machining processes, chemical processes, sintering o. Ä. Be introduced into the surface. For this purpose, laser or etching processes are particularly preferred.

Figur 1:

einen schematischen Querschnitt durch eine Presswalze;

Figur 2:

eine Draufsicht auf ein Stützelement 3;

The invention will be explained in more detail below with reference to several exemplary embodiments. In the attached drawing shows:

FIG. 1:

a schematic cross section through a press roll;

FIG. 2:

a plan view of a support member 3;

In the illustrated press rolls, the cylindrical and dimensionally stable roll shell 1 rotates about a stationary carrier 2. In this case, the roll shell 1 is pressed by a plurality of support elements 3 supporting and radially displaceable on the carrier 2 to form a press nip with a counter roll. For this purpose, the support elements 3 are arranged in a row axially next to each other.

To realize a hydraulic contact pressure, the piston-shaped support element 3 is guided in a cylindrical recess of the carrier 2. The pressure chambers 7 of the cylinder are supplied by a central supply line 8 in the carrier 2 with a pressure and lubricant, here oil.

The pressure and lubricant passes throttled through channels 9 in the support member 3 in a plurality of to the inside of the roll shell 1 open towards pressure chambers 6 of the support element. 3

These pressure chambers 6 are surrounded by running surfaces 5 in the form of webs which delimit and seal the pressure chambers 6.

During the rotation of the roll shell 1 lubricant is towed from the pressure chambers 6 in the gap between the running surfaces 5 and the inside of the roll shell 1, which also leads to the formation of a lubricant film on the inside of the roll shell 1.

As a result, there is a hydrostatic lubrication of the tread 5 during operation.

In order to prevent contact in case of failure of the supply of lubricant contact between the tread 5 and roll shell 1 to standstill of the roll shell 1, the corresponding surfaces are provided with micro-pockets 4. Of course, this requires a quick shutdown in case of failure.

After starting the machine, i. the rotation of the roll shell 1 is due to the formation of the lubricant film on the inside also for filling the micro-pockets 4 with lubricant. In order to be able to absorb a sufficient amount of lubricant without impairing the function and stability of the surfaces, the micro-pockets 4 should have a depth of between about 5 μm and 15 μm.

Should it now come to a failure of the supply of lubricant, so the lubricant in the micro-pockets 4 can still prevent the contact between the tread 5 and roll shell 1 for a limited, but usually sufficient time.

In a preferred and in the Figures 1 and 2 As shown, only the running surfaces 5 of the support elements 3 are provided with micro-pockets 4. This limits the effort and is usually sufficient.

In order to minimize the wear on the inside of the roll shell 1, this is coated with a wear-resistant layer 10.

The micro-pockets 4 are made by etching the surface.

LIST OF REFERENCE NUMBERS

1

roll shell

2

carrier

3

support element

4

micro-pockets

5

tread

6

pressure chamber

7

pressure chambers

8th

feed

9

channels

10

wearing course

Claims (8)

1. Press roll for a machine for producing and/or finishing a paper, board, tissue or other fibrous web, having a rotating roll shell (1) which is supported on at least one supporting element (3) of a stationary support (2), the running surface (5) of the supporting element (3) that comes into contact with the inside of the roll shell (1) being lubricated, characterized in that
   the running surface (5) has micro-pockets (4), at least in one section.
2. Press roll according to Claim 1, characterized in that
   the running surface (5) of the supporting element (3) is lubricated hydrostatically.
3. Press roll according to Claim 1 or 2, characterized in that
   the micro-pockets (4) have a depth between 0.1 µm and 500 µm, preferably between 5 µm and 15 µm.
4. Press roll according to one of the preceding claims, characterized in that
   the sections having the micro-pockets (4) have an open area of less than 60%, preferably between 10 and 30%.
5. Press roll according to one of the preceding claims, characterized in that
   the running surface (5) delimits at least one pressure chamber (6) that is open towards the inside of the roll shell (1) and filled with pressure and lubricating medium, preferably oil.
6. Press roll according to one of the preceding claims, characterized in that
   the inside of the roll shell (1) is covered with a wear-resistant layer (10), at least in one section, preferably in the sections covered by the running surface (5).
7. Press roll according to Claim 7, characterized in that
   the whole of the inside of the roll shell (1) is covered with a wear-resistant layer (10).
8. Method for producing the micro-pockets (4) according to one of the preceding claims, characterized in that
   these are introduced into the surface by means of lasers or etching processes.

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