DE102008040159A1 - Elastic roller cover for covering e.g. steel roller of paper processing machine, has pressure sensible layer arranged between adhesive layer and functional layer and/or between different positions of functional layer - Google Patents

Abstract

The cover (4) has a pressure sensible layer (7) formed adjacent to a roller core (5). The pressure sensible layer is arranged between an adhesive layer (8) and a functional layer (9) of the cover and/or between different positions of the functional layers. The pressure sensible layer has a label part (11), which is formed from a matrix material (10) such as plastic. The label part is designed in a form of pressure sensible color pigments or liquid crystal particle, where the label part is arranged in a casing.

Description

The The invention relates to an elastic cover for Rollers, in particular for rolls in paper machines and on a roller provided with such a cover.

It is known to equip rollers with sensors to obtain information about the operating condition of the rollers, in particular about temperature and pressure distributions in the roll cover. However, these sensors are mounted and designed so that they only provide information about the condition of the roll during normal operation when used as intended. Such sensors are for example on a roller as in the US 2003/0224917 A1 described provided. The sensors are integrated into the roll cover for recording temperature and / or pressure data and allow visual monitoring of these parameters without additional equipment.

There the provided with a plastic cover rollers, for example in The range of calendering of paper today is a very high quality are damaged due to material or Manufacturing errors are now very rare. This also applies to Material overloads under normal conditions Use. In contrast, however, the number of damages is decreasing to that, in all probability, but often not provable, due to overloads due to roll winder or massive wrinkling in the paper web arise.

From the EP 0 924 340 A2 For example, an elastic cover for a calender roll is known which is provided with a dye which changes its color as a function of the temperature. This property should be used for error detection. However, since detection of pressure spikes is not provided, corresponding events associated with high pressures, but not necessarily resulting in a temperature increase, can not be detected.

It is accordingly an object of the invention to provide a roll cover, which for the detection and permanent visualization of pressure peaks is designed even after the twisting off of the roller, as well as such Specify equipped roller.

The The object is achieved by the characterizing features of claim 1 solved in connection with the generic features.

According to the invention provided that the roll cover, which made multi-layered is, has at least one pressure-sensitive layer.

The at least one pressure-sensitive layer advantageously allows the detection and identification of pressure peaks, which due to heavy wrinkling, roll winder after breaking the paper web or foreign body passes through the roller nip occur.

Further advantageous aspects and further developments of the invention are based on Subclaims forth.

According to one preferred embodiment is the at least one pressure-sensitive Layer formed near the roll core. Thereby can the markings caused by the pressure peaks then preserved when the functional layer of the roller to the largest Part is turned off. In addition, it is taken into account in this way, at what depth the compressive stress was still present.

Especially Preferably, the at least one pressure-sensitive layer is between an adhesive layer and a functional layer of the roll cover arranged. This can be integrated in a simple way in a roll reference process.

Also an arrangement between individual layers of a multi-layer functional layer is conceivable.

additional can also be the adhesive layer and / or the functional layer of the roll cover be designed as a pressure-sensitive layer, which, for example in polyurethane roller covers in a simple manner possible is.

Around to detect the pressure peaks is in the at least one pressure-sensitive Layer contain at least one marking agent, which in a matrix material is embedded. The marking agent is designed in this way that it passes under the action of a threshold pressure Print goes through a color change. Thereby can easily and inexpensively pressure peaks, over the pressures occurring during normal operation lie, be captured without complicated electronic To require collection media.

From The advantage here is that the marking agent, for example, in Form of pressure-sensitive color pigments or liquid-crystal particles may be present, which in their physical properties the desired sensitivity can be interpreted.

According to an advantageous further development, the marking agent can also be present in capsules which are embedded in the matrix material and are breakable under the action of a pressure exceeding a threshold pressure. The marking agent can then be delivered to the surrounding matrix material, coloring it. This is advantageous because the encapsulated color pigments or liquid crystal particles are better protected and the response pressure is better adjustable by suitable dimensioning of the capsules.

Prefers is the color change of the marking agent or the coloring of the matrix material irreversibly, so as to obtain the label remains and when removing the roller and turning off the roller cover a closer analysis is open.

The Matrix material of the pressure-sensitive layer is preferably in Essentially plastic. The marker or capsules with the marker is easily embedded and simple in this in the course of coating a roller on the core can be applied.

following the invention with reference to the figures with reference to a preferred embodiment described by way of example. In show the figures:

1 a greatly simplified sectional view of an exemplary roller, which can be used in particular in a paper machine or a calender,

2A a greatly simplified section through a first embodiment of an inventively designed roller cover, and

2 B a greatly simplified section through a second embodiment of an inventively designed roller cover.

1 shows a highly schematic sectional view of two together a Walzennip 3 forming rollers 1 and 2 , which can be used in paper-making, -processing or -veredelnden machines, for example in the press section of a paper machine or in a calender. In particular, the invention is also suitable for use with Biegeeinstellwalzen. The second roller 2 is designed as a hard roller, for example as a steel roller, while the first roller 1 as an elastic roller 1 is formed and an elastic roll cover 4 which is on a hard roll core 5 , which may also be made of steel, for example, is applied.

Damage to with an elastic roll cover 4 provided rolls 1 pressure peaks occur especially where a rolling nip 3 for applying a defined pressure to a through the roll nip 3 guided material web 6 is fixed. The elastic roll cover 4 is designed for the forces acting on it during normal operation, but not for pressure peaks, which are exerted by foreign bodies, for example, which cause the rolling nip 3 to happen unintentionally. For example, tear the material web 6 From, it can come to roll winder, in which several layers of the web 6 , often under considerable wrinkling, the Walzennip 3 happen. This can damage the elastic roll cover 4 lead, which, however, often not immediately, but only later show and to detachment of the roll cover 4 from the roll core 5 can reach. Since the cause of the damage is usually not, especially not immediately, or only uncertain provable, it often comes to discrepancies between roller manufacturers and customers, since liability issues for expensive machine downtime can occur.

To provide simple and reliable evidence of events caused by pressure spikes outside of normal operating conditions, and thus not a lack of quality roll covers 4 are attributed, is proposed according to the invention, at least one pressure-sensitive layer 7 in the elastic roll cover 4 which is designed so that at pressure spikes that are significantly above the normal operating pressure, a mark in the pressure-sensitive layer 7 is produced. The marking is after removal and preferably also after the turning of the roller 1 Visible and evaluable, for example, in terms of their shape, which allows conclusions about the shape of a foreign matter leaving the marking or the extent of a roll winder, or in terms of their intensity, which allows conclusions about the magnitude of the applied pressure.

In 2A is a first embodiment of an inventively designed elastic roller cover 4 in a highly schematic sectional view according to section II in 1 shown.

The thickness of the individual parts of the elastic roll cover 4 is not to be seen to scale, but serves only to clarify the proportions. Likewise, the curvature of the roll core 5 and the roll cover 4 neglected.

The embodiment according to 2A points to the roll core 5 an adhesive layer 8th on which of the connection of the example metallic roller core 5 with a functional layer 9 the elastic roll cover 4 serves.

As materials for the adhesive layer 8th and the functional layer 9 Any suitable, suitable for elastic roller covers 4 usual materials to the respective position of the elastic roller 1 are adjusted. The roll core 5 Besides metal, it can also be made of other suitable materials such as carbon fiber.

The pressure-sensitive layer according to the invention 7 is between the adhesive layer 8th and the functional layer 9 arranged. Alternatively, it is also possible to use the adhesive layer 8th and / or the functional layer 9 even in the form of a pressure-sensitive layer 7 form or the pressure-sensitive layer 7 between further layers, from which the functional layer 9 can be constructed, to arrange.

The pressure-sensitive layer 7 according to 2A Contains in a suitable matrix material 10 at least one marker 11 which in the exemplary embodiment directly into the matrix material 10 is embedded. The matrix material 10 is preferably the functional layer forming material, ie z. For example, epoxy. As a marker 11 are known pressure-sensitive color pigments or liquid crystals, which change permanently or reversibly under pressure. In terms of the detectability of pressure peaks is an irreversible, permanent coloration of the marking agent 11 desirable.

In the production of the pressure-sensitive layer 7 For example, in a simple way, the matrix material 10 with the marker 11 mixed and then on the adhesive layer 8th be applied, for example, by conventional winding, injection or casting process.

On the pressure-sensitive layer 7 can then be another layer structure of one or more, the functional layer 9 forming layers take place.

Furthermore, it is possible to have not just one but several pressure-sensitive layers 7 , In particular, with intermediate layers, provided in order to obtain a more differentiated image of the pressure peak.

In 2 B is in the same representation as in 2A A second embodiment of an inventively designed elastic roll cover 4 shown.

The marker 11 is in this case in encapsulated form, the color pigments are in capsules 12 included, which in the matrix material 10 are embedded. When a pressure spike occurs, the capsules break 12 in the area subjected to the high pressure and give their contents to the surrounding matrix material 10 which is dyed by and a mark 13 receives. This is preferably also by appropriate choice of the marking agent 11 irreversible.

In the in 2 B Thus, the embodiment shown does not need the marking means 11 even be pressure-sensitive, it is sufficient a simple dye that deals with the matrix material 10 under formation of the mark 13 combines. This is then in the pressure-sensitive layer 7 also after turning off the roll cover 4 visible and accessible to analysis.

To rule out marks 13 by color change of the marking agent 11 or by leakage of labeling agent 11 from the capsules 12 occur in non-critical pressure ranges, the pressure-sensitive layer 7 or the encapsulation of the marking agent 11 be designed so that only at pressures that are significantly above the pressure conditions in normal operation, a mark is made. For example, for typical calender applications, the pressure threshold would be above a set pressure of 60 MPa. In this way, a mark, for example, by slight wrinkles, without consequences for the roll cover 4 stays, be avoided.

The invention is not limited to the illustrated embodiments and also for other layer structures of elastic roller covers 4 applicable.

1

elastic roller

2

steel roll

3

roll nip

4

elastic roll cover

5

roll core

6

web

7

pressure Sensitive layer

8th

adhesive layer

9

functional layer

10

matrix material

11

marker

12

capsules

13

mark

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 2003/0224917 A1 [0002]
• EP 0924340 A2 [0004]

Claims (14)

Elastic roller cover ( 4 ), in particular for rolls ( 1 ) of paper machines, which roll cover ( 4 ) is multi-layered, characterized in that the roll cover ( 4 ) at least one pressure-sensitive layer ( 7 ) having. Elastic roller cover according to claim 1, characterized in that the at least one pressure-sensitive layer ( 7 ) near a roll core ( 5 ) is trained. Elastic roller cover according to claim 2, characterized in that the at least one pressure-sensitive layer ( 7 ) between an adhesive layer ( 8th ) and a functional layer ( 9 ) of the roll cover ( 4 ) and / or between different layers of the functional layer ( 9 ) is arranged. Elastic roller cover according to claim 3, characterized in that the adhesive layer ( 8th ) and / or the functional layer ( 9 ) as a pressure-sensitive layer ( 7 ) is trained. Elastic roller cover according to one of claims 1 to 4, characterized in that the at least one pressure-sensitive layer ( 7 ) at least one marking agent ( 11 ) contained in a matrix material ( 10 ) are embedded. Elastic roller cover according to claim 5, characterized in that the marking agent ( 11 ) undergoes a color change under the action of a pressure exceeding a threshold pressure. Elastic roller cover according to claim 6, characterized in that the color change of the marking agent ( 11 ) is irreversible. Elastic roller cover according to one of claims 5 to 7, characterized in that the marking agent ( 11 ) in the form of pressure-sensitive color pigments or liquid-crystal particles. Elastic roller cover according to claim 5, characterized in that the marking agent ( 11 ) in capsules ( 12 ) present in the matrix material ( 10 ) are embedded. Elastic roller cover according to claim 9, characterized in that the capsules ( 12 ) are rupturable under the action of a pressure exceeding a threshold pressure, so that the marking agent ( 11 ) into the surrounding matrix material ( 10 ) is deliverable under coloring of the same. Elastic roller cover according to claim 10, characterized in that the coloring of the matrix material ( 10 ) is irreversible. Elastic roller cover according to one of claims 6 to 11, characterized in that the threshold pressure is significantly greater than that during normal operation on the roll cover ( 4 ) acting pressure is. Elastic roll cover according to one of claims 1 to 12, characterized in that the matrix material ( 10 ) consists essentially of plastic. Roller ( 1 ) with a roll core ( 5 ) and one on the roll core ( 5 ) formed elastic roll cover ( 4 ) according to one of claims 1 to 13.