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Title:
ARRANGEMENT, SYSTEM AND METHOD FOR MEASURING OPERATING CONDITIONS OF AN ELEMENT ROTATING IN A WEB FORMING MACHINE OR A FINISHING MACHINE
Document Type and Number:
WIPO Patent Application WO/2007/128877
Kind Code:
A1
Abstract:
The invention relates to an arrangement in a web forming machine or a finishing machine (37, 42) for measuring operating conditions of a rotating element, such as, for example, a roll (10.1 - 10.5). In the invention, the rotating element is equipped with thin-film sensor means (12, 12 ') for measuring the operating conditions. In addition, the invention also relates to a corresponding system and method.

Inventors:
HOLOPAINEN KARI (FI)
HYVOENEN HANNU (FI)
KOROLAINEN TOMMI (FI)
Application Number:
PCT/FI2007/050251
Publication Date:
November 15, 2007
Filing Date:
May 07, 2007
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
METSO PAPER INC (FI)
HOLOPAINEN KARI (FI)
HYVOENEN HANNU (FI)
KOROLAINEN TOMMI (FI)
International Classes:
G01M13/04; D21F7/00; D21G9/00; F16C13/02; G01K13/08; G01L5/00
Foreign References:
US20070098311A12007-05-03
DE10313060A12004-10-21
FI20002739A2002-06-15
FI108556B2002-02-15
Other References:
"Pioneering the new standard in force measurement technology. Custom force measurement - product catalog", THE INSTRUMENTATION COMPANY NOSHOK, 21 June 2004 (2004-06-21), pages 2, 7, Retrieved from the Internet
Attorney, Agent or Firm:
KESPAT OY (Jyväskylä, FI)
Download PDF:
Claims:

CLAIMS

1. An arrangement in a web forming or finishing machine (37, 42) for measuring operating conditions of a rotating element, 5 such as, for example a roll (10.1 - 10.5), characterized in that said rotating element (10.1 - 10.5) is equipped with thin- film sensor means (12, 12') for measuring said operating conditions .

10 2. An arrangement according to claim 1 , characterized in that said rotating element is a press roll (10.1, 10.2) or a calender roll (10.2, 10.3, 10.5) which includes a rotating element (13, 14) equipped with bearing means (11), and which bearing means (11) include the support bearings (11.1, 11.2, 11.3, 114,

15 115) of the roll (10.1 - 10.3, 10.5).

3. An arrangement according to claim 1 or 2 , characterized in that said rotating element is the shaft (14) of the roll (10.1, 10.3) or the shell (13) of the roll (10.2, 10.5).

20

4. An arrangement according to any of claims 1 - 3 , characterized in that the thin-film sensor means (12, 12') are arranged in connection with the support bearings (11.1, 11.2, 11.3, 114, 115) .

25

5. An arrangement according to claim 4, characterized in that the thin-film sensor means (12, 12') are arranged in connection with the fixed race (15, 16) of the support bearing (11.1, 11.2) . 0

6. An arrangement according to claim 5, characterized in that the thin-film sensor means (12, 12') are arranged in connection with the fixed race (15, 16) of the support bearing (11.1, 11.2), in its loading range (30). 5

7. An arrangement according to any of claims 1 - 6 , characterized in that the support bearing (11.1, 11.2) is formed of at least two roller races (19.1, 19.2), where at least one thin- film sensor (12, 12') is arranged for each roller race (19.1, 19.2) .

8. An arrangement according to any of claims 1 - 7, characterized in that said rotating element is a deflection-compensated roll (10.2, 10.5), which additionally includes means (35, 36) for loading the roll (10.2), and in which said thin-film sensor means (12) are arranged in connection with said loading means (35, 36) .

9. An arrangement according to claim 8 , characterized in that the means for loading the roll (10.2) include several loading elements (35) having thin-film sensor means (12) arranged in connection of at least a part thereof.

10. An arrangement according to any of claims 1 - 9, character- ized in that the bearing means include slide bearings (11.3,

114, 115), with the thin-film sensor means (12) arranged to measure loading pressures and/or temperature, for example, over the sliding surfaces and/or at the slide shoe pockets and cavities (61, 62, 64, 65) thereof, as said operating condi- tions .

11. An arrangement according to any of claims 1 - 10, characterized in that said rotating element is a belt roll (10.4), with the thin-film sensor means (12) arranged to measure load- ing pressures and/or temperature, for example, over the sliding surfaces (38) of its slide shoe (39) and/or at the pockets (38') of the slide shoes (39), as said operating conditions.

12. A system in a web forming or finishing machine (37, 42) for monitoring and/or controlling operating conditions of a rotating element, such as, for example, a roll (10.1 - 10.5), where

the system includes processing unit means (CPU) performing monitoring and/or control of the machine (37, 42) , characterized in that at least part of the rotating elements (10.1 - 10.5) of the web forming or finishing machine (37, 42) is 5 equipped with thin-film sensor means (12, 12') , which are arranged to provide measurement results to said processing unit means (CPU) .

13. A system according to claim 12, characterized in that the 10 thin-film sensor means (12, 12') are arranged in connection with the bearing means (11.1 - 11.3, 114, 115) of the roll (10.1 - 10.5) for providing at least one measurement result to the processing unit means (CPU) concerning the operating conditions of the roll (10.1 - 10.5) .

15

14. A system according to claim 12 or 13, characterized in that the processing unit means (CPU, 101) is arranged to control the regulation of the lubrication oil flow of the bearing means (11.1 - 11.3, 114, 115) of the roll (10.1 - 10.5) on the basis

20 of the measurement performed with the thin-film sensor means (12, 12') .

15. A system according to any of claims 12 - 14, characterized in that by using the thin-film sensor means (12, 12'), loading

25 focused on the bearing means (11.1, 11.2) is arranged to be determined, for which loading a criterion value is set, upon fulfilling of which an axial load according to the set value is arranged to be focused on the bearing means (11.1, 11.2).

30 16. A system according to claim 15, characterized in that actuators (20) are arranged in connection with the roll end for moving the position of the fixed race of the roll bearing (11) in the axial direction on the basis of the measurement performed with the thin-film sensor means (12, 12').

35

17. A system according to any of claims 12 - 16, characterized in that the thin-film sensor means (12, 12') are arranged to measure the nip forces of the roll nip constructions (45) by measuring forces at the fixed races (15, 16) of the bearing

5 means (11.1, 11.2) and on the basis of the which measurement the calendering process is arranged to be controlled.

18. A method in a web forming or finishing machine (37, 42) for measuring operating conditions of a rotating element, such as,

10 for example, a roll (10.1 - 10.5), characterized in that the operating conditions of the rotating element (10.1 - 10.5) are measured with thin-film sensor means (12, 12').

19. A method according to claim 18, characterized in that the 15 regulation of the lubrication oil flow of the bearing means

(11.1, 11.2, 11.3, 114, 115) of the rotating element (10.1 - 10.5) is controlled on the basis of the measurement performed by the thin-film sensor means (12, 12').

20 20. A method according to any of claims 18 or 19, characterized in that by using the thin-film sensor means (12, 12'), loading focused on the bearing means (11.1, 11.2) is determined for controlling the axial load to be focused on the bearing means (11.1, 11.2).

25

21. A method according to claim 20, characterized in that the position of the fixed race of the bearing means (11.1, 11.2) of the roll (10.1 - 10.3) is moved in the axial direction in connection with the roll (10.1. - 10.3) end on the basis of the

30 measurement performed with the thin-film sensor means (12, 12' ).

22. A method according to any of claims 18 - 21, characterized in that the thin-film sensor means (12, 12') are used to mea-

35 sure the nip forces of the roll nip constructions (45), which measurement is taken at the fixed races (15, 16) of the bearing

means (11.1, 11.2) and on the basis of the which measurement the calendering process is controlled.

23. A method according to any of claims 18 - 22, characterized in that the thin-film sensor means (12) are used to measure loading pressures and/or temperature, for example, over the sliding surfaces of the slide bearings (11.3, 114, 115) and/or at the slide shoe pockets/cavities (61, 62, 64, 65), as said operating conditions of the bearing (11.3).

24. A method according to any of claims 18 - 23, characterized in that the thin-film sensor means (12) are used to measure loading pressures and/or temperature, for example, over the sliding surfaces (38) of the belt roll (10.4) slide shoe (39) and at the slide shoe (39) pockets (38'), as said operating conditions .

Description:

ARRANGEMENT, SYSTEM AND METHOD FOR MEASURING OPERATING CONDITIONS OF AN ELEMENT ROTATING IN A WEB FORMING MACHINE OR A FINISHING MACHINE

The invention relates to an arrangement in a web forming or a finishing machine for measuring operating conditions of a rotating element, such as, for example, a roll. In addition, the invention also relates to a corresponding system and method.

Paper, pulp, tissue and board machines as well as paper finishing and converting machines have several rotating elements mounted with antifriction bearings, for example. Measuring operating conditions of elements, such as, for example, rolls, mounted with antifriction bearings is extremely challenging. A real-time awareness of the actual operating conditions of rolls would be important as regards appropriate performance of the roll, for instance, as well as the condition monitoring.

The measurement of operating conditions according to prior art is often based on computational methods. These are rather incapable of taking into account effects due to changing loading conditions, for instance. Known methods often measure only one parameter that is quite distant relative to the actual roll performance. Based on it, it is possible to calculate- /estimate the actual operating condition of interest. In this, it is indeed impossible to talk about any real-time measuring of actual operating conditions, which could be used to maintain or control the operation of rolls and of the production process in general in real-time and rationally, or that it would even be possible to predict problems and damages being under development .

The determination of the lubrication condition of a roller bearing on the basis of the calculatory loads and preassessed environmental conditions is known prior art. In reality, oper-

ating conditions of a bearing are often formed of a sum of several factors, which are not considered by the mainly static calculation model. These include, for instance, the environmental temperature and air flows as well as the radial and axial loads produced by the nip and/or the clothing. These loads are essentially influenced by the friction and fit between the bearing housing and the outer race of the bearing, and their deformations. In addition, changes in the oil properties (for example, viscosity) also have an influence on the lubrication condition.

Due to the above reasons, determining the lubrication condition and the oil amount to be supplied to the bearing has been very difficult and involves uncertainty factors. For the lubrica- tion, the amount of oil supplied to the bearing has been monitored, which does not indicate the actual lubrication situation.

An improvement to this is provided by a so-called self-con- trolled lubrication oil regulation. In this, the lubrication condition is assessed using various calculation parameters. The oil flow is the control parameter and the oil temperature is the regulation parameter. For the regulation, the machine's running speed, oil temperature and maximum load, for instance, are measured/defined. The maximum load has been assessed on the basis of the rough load information from the roll nip, which information has been received based on the hydraulic pressure applied in nip loading. The oil temperature has been measured with sensors . When the sensor has detected a temperature rise in oil, the oil flow has consequently been increased.

Besides the lubrication control, problematic is also the measurement of the condition of loading focused on the bearing. In highly loaded roller bearings, a micro-movement takes place between the outer race of the bearing and the housing. Due to this the metal surfaces become sticky (cold-welded, "micro-

contacted"). The bearing at the free end of the roll cannot slide in the housing in the axial direction, which leads to erroneous loading of the bearing. Consequently, the load is distributed in the bearing to only one of the roller rows, which causes an overload and a possible bearing failure. The axial movement can be prevented also because of a bearing tilt. In this case the outer race of the bearing tends to tilt in the bearing housing, which leads to that the edge of the race "engages" with the housing changing the friction coefficient.

In bearings equipped with antifriction elements, a problematic situation is created also by the "zero load". The rotation speed of the antifriction elements slows down, or the rotation even stops completely because of friction drags caused by the lubricant and the bearing support in case the bearing load is very small . In certain rolls the bearing can enter into such a zero load condition. Sliding of antifriction elements makes the oil film thinner, or the lubrication film can fail altogether. A metal-metal contact can be created in the bearing causing a surface damage and a possible bearing failure. Known condition monitoring methods provide indications only after a damage of a certain degree has already occurred.

Regarding the monitoring of erroneous loading conditions of bearing in general, the prior art technique is represented by a temperature sensor arranged on the outer surface of the bearing race. As a measuring method, however, this involves a lot of delay, since heat must be conducted via the bearing race. In addition, a temperature measurement performed accord- ing to this method is skewed by the oil flow supplied to the bearing through the bearing race, which cools down the measuring point more than the roller race under the load.

Besides web forming machines, accurate measuring of the loads of rolls equipped with antifriction bearings (intermediate rolls and deflection-compensated/zone-controlled rolls) has

been difficult also in multiroll calenders, which can lead to that loading easily drifts to the 0 load zone. Today it is not possible to rely on operating windows safe for the bearing defined by mere calculation, since there are unknown friction forces affecting in the roll stack (for example, in lever mechanisms and deflection-compensated/zone-controlled rolls).

The object of this invention is to provide an arrangement for measuring operating conditions of a rotating element in a web forming or finishing machine. The characteristic features of the arrangement according to the invention are set forth in claim 1. The invention also relates to a system for measuring operating conditions of rotating elements in a web forming or a finishing machine as well as a method, the characteristic features of which are set forth in claims 12 and 18.

In the arrangement according to the invention, a rotating element, such as, for example, a roll, is equipped with thin- film sensor means for measuring operating conditions.

Thin-film sensors can be arranged in connection with the roll in many various ways. For example, according to one embodiment, they can be associated with the support bearings of a rotating element. According to one embodiment, the rotating part of a roll can be, for example, the roll shell. According to another embodiment, the rotating part can also be the roll shaft.

According to one embodiment, thin-film sensor means can be placed in the roll, in its support bearings. According to a more specific embodiment, the thin-film sensor means can then be associated with the fixed race of the support bearings, for instance. Thus the sensor means can be located in the loading range of the race, for example. If the support bearing is formed of at least two roller races, at least one thin-film sensor can be arranged for each roller race. The invention can be equally applied also in slide bearings.

According to one embodiment, the thin-film sensor assembly can be connected to the control of a web forming or finishing machine for one or even more purposes. One example of such a purpose is the condition monitoring of the bearing means. Thus, according to one embodiment, the regulation of the lubrication oil flow of the bearing means can be controlled on the basis of the measurement carried out with the thin-film sensor means.

This allows optimizing friction losses and even preventing excessive thinning of the lubricant film.

Thin-film sensor means can also be used to determine the load focused on the bearing means . One example of this is the problematic zero load. On the basis of this, upon fulfilling of the criterion according to as set, such an axial load that returns the working condition of the bearing can be focused on the bearing.

A thin-film sensor assembly can also be applied for active on- the-run control of the process conditions. Then the sensor assembly can be associated with the roll's loading equipment, for example.

Owing to the invention, operating conditions can be adjusted based on the actual operating conditions, which are revealed with the measurements carried out by the thin-film sensor means. The invention removes controls based on estimation and calculatory/theoretical observations. A real-time awareness enabled with the invention enables preventive maintenance along with which it can also be used to prevent the development of damages .

The arrangement according to the invention is simple both for operation, installation, calibration and possible replaceability . Furthermore, it is very durable. Other additional benefits achievable with the arrangement, system and

method according to the invention become evident from the description, and the characteristic features are described in the appended claims .

The invention, which is not limited to the embodiments set forth below, is described in more detail by making reference to the enclosed drawings, in which

Figure 1 is a rough diagram showing a first application example of a bearing according to the invention,

Figure 2 is a rough diagram showing a second application example of a bearing according to the invention, Figure 3a is a lateral view of an application example of a bearing according to the invention,

Figure 3b is a rough diagram showing a third application example of a bearing according to the invention, Figure 4 shows a first application example of an arrangement according to the invention in a press center roll,

Figure 5 shows a second application example of an arrangement according to the invention in a deflection-compensated roll,

Figure 6 shows a third application example of an arrangement according to the invention in a calender thermoroll,

Figure 7a shows a first application example of an arrangement according to the invention in an online calender,

Figure 7b shows a second application example of an arrangement according to the invention in a multiroll calender, Figure 7c shows a fourth application example of an

arrangement according to the invention in a roll mounted with slide bearings,

Figure 8 shows an application example of a system according to the invention in a web forming machine,

Figure 9 shows an application example of applying a sensor assembly according to the invention for eliminating the zero load,

Figure 10 shows an application example of an arrange- ment according to the invention in a press shoe roll, and

Figure 11 shows an application example of the design of a sensor assembly according to the invention.

Figures 1 and 2 show rough diagrams illustrating some examples of the bearing means 11, in connection with which the sensor assembly 12 according to the invention can be applied. Corresponding reference numbers are used for identical functional parts. The number of such bearings 11 can be one or more in a web forming or finishing machine, for example. The bearing 11 enables the rotating movement for the element 10 or a part of the element 10 included in the machine. Examples of web forming machines are paper or board machines (Figure 8) , tissue ma- chines, and pulp machines. Examples of finishing machines are calenders (Figures 7a and 7b), slitter winders, and machine reels. A finishing machine can be a part of the actual web forming machine (online) or essentially separated from it (offline) .

Examples of rotating elements include various rolls and cylinders located in several di f f erent sections of the machine . Examples of these include suction rolls , press rol ls 10 . 1 (Figure 4 ) , deflection-compensated rolls 10 .2 (Figure 5 ) , dryer cylinders , lead rolls , calender rolls , sof t calender rolls ,

thermorolls 10.3 (Figure 6), glazing calenders, reel spools and reel drums, shoe rolls 10.4 (Figure 10).

Although Figures 1 and 2 show a spherical roller bearing, in this connection it should be understood just as one example of the bearing types used in a production machine or a finishing machine. Other possible bearing types could include, for example, cylindrical roller bearings, angular contact ball bearings, three-membered ring compound bearings, slide bearings, and spherical plain bearings.

For example, a spherical roller bearing 11 is used in the machines as a support bearing 11.1, 11.2 for rotating elements

(Figures 4 - 6) . In its basic form, the bearing 11 is generally formed of an outer ring 16, an inner ring 15, and antifriction elements 18 and supports 17 located between them. In this case the antifriction elements are rollers 18. They roll along raceways 19.1, 19.2 formed of rings 15, 16. The support 17 can encircle the antifriction elements 18. On the other hand, besides having a circular design, the support can also be a so- called massive support.

The bearing frames 15, 16 form now two roller races 19.1, 19.2 adjacent in the axial direction. Naturally, the bearing unit 11 can have even more roller races or only just one. The roller races 19.1, 19.2 functioning as support bearings 11.1, 11.2 are in a spherical arrangement. Thus the inner surface 16.1 of the outer race 16 and the outer surface 15.2 of the inner race 15 assume a spherical curved shape in the axial direction. The basic technology related to spherical roller bearings 11 is quite apparent to one skilled in the art and therefore will not be described in more detail in this connection. As such, the bearing assembly 11 can be of a technology which is already fully known or only just under development; the invention does not set any limits on this.

In the embodiment of Figure 1, thin-film sensor means 12 are integrated in the constructions of the bearing 11, on its outer race. The sensor means are formed of at least one unity formed of a functional sensor 12. Here the total number of sensors 12 5 visible is eight. Part of the sensors 12 can be on the outer surface 16.2 of the outer ring 16. Then these sensors 12 are against the inner race of the bearing pedestal or a possible sleeve socket assembly (not shown) . Part of the sensors 12 can be on the inner surface 16.1 of the outer ring 16. Then the 10 sensors 12 are against the rolling rollers 18.

The sensors 12 can be located at uniform intervals around both roller races 19.1, 19.2, where one or both roller races 19.1, 19.2 have at least one sensor 12. Equipping both roller races 15 19.1, 19.2 with a sensor assembly 12 is advantageous as regards the balance of the bearing 11. By arranging several sensors 12 per each roller race 19.1, 19.2 it is possible to indicate race-specific load over the race, deviations appearing therein, and events in general (not necessarily/mere loading) .

20

In the embodiment of Figure 2, the sensors 12 are integrated in the inner ring 15, either to its inner race 15.1 and/or outer race 15.2. Here, too, both roller races 19.1, 19.2 are equipped with sensors 12. 25

It is apparent for one skilled in the art that the basic principle of the invention does not limit the arrangement method of the sensors 12 to any particular arrangement in the bearing and their rings 15, 16. The sensors 12 can be in connection with

30 even both rings 15, 16, or even on all the race surfaces 15.1, 15.2, 16.1, 16.2 of the rings 15, 16, associated with the surfaces, or at least in part of their surfaces. In addition, the number of the sensor units 12 or the positioning in connection with the bearing 11 can be extremely free within the

35 boundaries of the basic idea of the invention.

According to one embodiment, thin-film sensors 12 or at least the main part of them can be arranged in connection with the fixed bearing ring 15, 16 of only the bearing 11, such as, for example, the support bearings 11.1, 11.2 shown in Figures 4 - 6, being located on its one or more surfaces. If arranging the sensor assembly 12 on the loading surface is for some reason difficult, impossible or unreliable, it can be arranged only on the outer surface 16.2 of the outer ring 16 or on the inner surface 15.1 of the inner ring 15.

More particularly, according to one embodiment, the sensors 12 can be arranged on such a surface of the fixed bearing ring that is not in contact with the antifriction elements 18. Thus it is easy to arrange wiring or similar physical data transfer from the sensors 12 to the control system CPU. Naturally, it is also possible to apply telemetry in the data transfer, in which case it is not necessary to limit to equipping only the fixed race with sensors. Various "dragging contact systems" may also be useful.

The embodiment shown in Figure 1 can be fixed as regards the outer ring 16 and rotating as regards the inner ring 15. Examples of such applications are shown in Figures 4 and 6. Correspondingly, the application according to Figure 2 is fixed as regards the inner ring 15 and rotating as regards the outer ring 16. A corresponding example of an application is shown in Figure 5.

Figure 3a illustrates one embodiment of the bearing 11 shown in a lateral view. According to this, weighted positioning of the sensors 12 at some point of the race is also possible. The thin-film sensor means 12 can be in connection with the fixed race 15, 16 of the support bearing 11 in such a way that their location is weighted to be in the loading zone 30 of the bear- ing 11.1, 11.2. Now the loading zone 30 is the sector area below the bearing 11, which can be even flexible to some ex-

tent. The loading zone 30 can have sensors 12 placed at more frequent intervals than in other parts of the race 16.

The embodiment according to Figure 3b shows still another way of realizing the invention. Now the bearing 11 is shown on its bearing pedestal 31. In this case, too, the outer ring 16 of the bearing is fixed, while the shaft 14 connectable to the inner ring 15 of the bearing 11 rotates. Now the sensor means 12 are not fixedly integrated to the surface of the bearing 11, but form a retrofittable component 12' of their own. The sensor 12' is now integrated to a suitable base 32. The shape of the base 32 can be such that it is easily installable between the bearing housing formed by the bearing 11 and the pedestal 31. The shape of the base 32 can be a wedge-shaped body or a sleeve, for example. Thus the sensor assembly can be even upgraded by replacing it easily with a new one. Naturally, sensors 12 integrated in the actual bearing ring constructions 15, 16 can also be applied in the same bearing construction.

Figures 4 - 6 show some arrangements enabled " by the invention, which can be used to measure the operating conditions of a rotating element, such as, for example, a roll 10.1 - 10.3 of a web forming or finishing machine. Referring to Figures 4 - 6, it is to be understood that they are not intended to show roll, bearing and machine constructions with fine details but extremely roughly on a very basic level . As already mentioned above, the rolls 10.1 - 10.3 include bearing means 11, which enable the rotation of one or more parts 13, 14 of the roll 10.1 - 10.3. Now these rolls 10.1 - 10.3 are equipped with thin-film sensor means 12 for measuring/controlling the operating conditions of the roll and/or the production process in general .

Figure 4 shows one roughly simplified example of a press roll, more particularly of a press center roll 10.1. The position of

the center roll 10.1 in the press section 51 of a paper machine is shown in Figure 8.

The bearing means 11 shown in Figures 1 and 2 are in the bear- ing pedestals 31 functioning as support bearings 11.1. The shaft 14 of the roll 10.1 is mounted with bearings in connection with the bearing pedestal 31 rotating at the same time the shell component 13 of the roll as well. Thus, here the rotating element is the roll 10.1 with its shafts 14 and shell 13 over its entire machine cross-directional length. The thin-film sensor means 12 are now associated with, for example, the fixed bearing ring of the support bearings 11.1, which is the outer ring 16 of the bearing 11.1. Generally, regardless of the embodiment, sensors 12 can be used to measure the temperature and/or pressure (loads), for instance, as operating conditions.

Figure 5 shows one roughly simplified example of a press roll, more particularly of a deflection-compensated roll 10.2 of a press. In the press section 51, a deflection-compensated and zone-controlled roll 10.2 provides the effect that the manufactured product has a desired quality over the entire web width. A deflection-compensated zone-controlled roll 10.2 can also be applied in a calender 53, for example. The position of a deflection-compensated roll 10.2, 10.2' in the press section 51 of a paper machine as well as in an online calender 53 is shown in Figure 8.

The spherical roller bearings 11 shown in Figures 1 and 2 are now inside the shell 13 of the roll 10.2. In this case, too, they can be said to function as the support bearings 11.2 of the shell 13. The deflection-compensated roll 10.2 is loaded against the counter roll 10.3 in the calender 53 in a manner known as such.

The deflection-compensated roll 10.2 is formed of a non-rotating shaft 14' and a rotating roll shell 13, equipped with

bearing means 11.2 according to the invention, which rotates around the shaft 14 ' supported by spherical roller bearings

11.2 according to the invention. The shaft 14' located within the shell 13 comprises independently adjustable pressure ele- ments 35. The elements 35 support the shell 13 hydrostaticalIy, and they are used to adjust the deflection of the roll 10.2. The shell 13 is adjusted to the shape of the counter roll 10.1,

10.3 shell, for example.

The roll 10.2 shaft 14 is connected via spherical plain bearings 33, for example, to the bearing pedestals 34. The shell component 13 of the roll connects to the shaft 14 ' via roller bearings 11.2, for example. Here the rotating element is thus the shell 13. The thin-film sensor means 12 are now in connec- tion with, for instance, the fixed bearing ring of the shell 13 support bearings 11.2, which in this case is the inner ring 15 connected to the shaft 14' of the bearing 11.2. The sensor equipment 12 can also be in the spherical plain bearing 33 measuring the total nip load, for example.

Figure 6 shows one roughly simplified example of a calender roll, more particularly a calender thermoroll 10.3. The position of the thermoroll 10.3 in a paper machine online calender 53 is shown in Figure 8, and Figures 7a and 7b depict calender- ing applications in which deflection-compensated and/or thermorolls 10.2, 10.3 according to the invention can be applied. A calender thermoroll that is made of steel, for example, can be heated with a suitable heat transfer material. The nip load i.e. the press force is determined according to the paper grade produced. The basic structure of the calender roll 10.3 corresponds greatly to the press center roll 10.1, which was already described above. Here, too, the bearing means 11 consist of the support bearings 11.1 located in the bearing pedestals 31 at the roll 10.3 ends with the thin-film sensor means 12 being arranged in connection with them.

Figure 7a is a diagrammatic view of one example of a soft calender application. Here the top roll can be a thermoroll, such as, for example, the thermoroll 10.3, and the bottom roll can be a deflection-compensated roll 10.2 (for example, a zone- controlled SYM type) . Sensor assemblies 12 according to the invention can be present in both rolls 10.2, 10.3, for example in their bearing assemblies 11.1, 11.2 and/or loading elements 35.

Figure 7b is a diagrammatic view of an embodiment for a multiroll calender 42. Here the top roll 10.2' of the roll stack 10 ' illustrated on the right of the diagram can be a fixed deflection-compensated roll, and the bottom roll 10.2 can be of the deflection-compensated type and additionally of the type loadable by the bearings 11.2. Between the top and bottom rolls 10.2, it is possible to place alternately, for example, intermediate rolls and thermorolls 10.3.

The type of the bottom roll 10.2 shown in more detail in Figure 7b can be a hydraulically deflection-compensated zone-controlled roll (for example, the SYM-Z roll type of the applicant) . The deflection compensation of the roll 10.2 is realized by means of hydraulic loading elements 35 located on the shaft 14' of the roll 10.2, which influence the roll 10.2 shell 13 by supporting it zone-wise. The loading elements 35 compensate the deflection of the roll 10.2 in a desired manner providing thus a desired uniform linear load. In addition, besides the deflection compensation, the loading elements 35 provide a desired profiling as each element 35 can be adjusted as required ac- cording to each profiling need. The sensor assembly 12 can be in different positions in the loading means 35. As one example of such positions, the sliding surface of the loading element 35 can be mentioned.

The deflection-compensated roll 10.2 can be a so-called impact- type roll or also a non-impact-type roll. In an impact-type

roll (for example, the SYM-ZS roll type of the applicant), between the bearings 11.2 of the roll shell 13 and the roll 10.2 shaft 14' there are loading means 36. The loading means 36 can be used to move the entire shell 13 in the nip 45 direction while the shaft 14' remains in place. In this case, against the inner surface 15.1 of the inner race 15 of the bearings 11.2 of the shell 13, there may be a loading ring, known as such, which is supported to the roll 10.2 shaft 14'. In such an impact-type roll 10.2, the roll 10.2 shell 13 can be driven against the counter roll.

If the bearings 11.2 and/or the loading ring and/or the hydraulic loading means 36 are equipped with sensors 12 according to the invention, then the edge areas of the web run through the calender 42 can also be controlled and adjusted more accurately than before by means of loading focused on the bearings 11.2. The sensor assembly 12 according to the invention reveals the actual load in the edge areas of the roll 10.2. This has an essentially reducing effect on the amount of developing broke, for example, because edges cannot have been used earlier.

As known, spherical roller bearings 11.2 at the shell 13 end can be replaced also with slide bearings 11.3 known as such. The sensor assembly according to the invention can be equally applied in the slide bearing assembly 11.3 regardless of the roll position. A slide bearing roll can be normal for its basic functions or a self-loading roll with a moving shell. Figure 7c is a diagrammatic cross-sectional view showing one application example of fitting the roll 10.5 with an impact-type slide bearing assembly. Then the sensors 12 can be located, for example, on the slide surfaces and/or in the pockets /cavities 61, 62, 64, 65 of the slide bearing elements 114, 115. Figure 7c shows some exemplifying positions for the sensors 12.

Also in Figure 7c, the roll 10.5 shaft is indicated with reference number 14 ' and the roll shell with reference number 13.

The roll shell 13 is supported against the inner surface 13 ' of the roll shell by means of loaded slide bearing elements 114, 115. In addition, the slide bearing elements 114, 115 are equipped with seals 70, 71 and pressurizable cavity spaces 61, 62. For both slide bearing elements 114, 115, the roll 10.5 shaft 14' is fitted with frame components 63, 63a extending to the cavity spaces 61, 62 of the slide bearing elements 114, 115. As to their structure, the slide bearing elements 114, 115 can be conventional as such, equipped with oil pockets 64, 65 on their outer surfaces. The oil pockets are connected to pressure spaces 61, 62 via capillary bores 66, 67 leading through the slide bearing elements. The basic technologies related to the rolls' slide bearing assemblies are known as such for one skilled in the art; the invention does not require particular technical solutions regarding them. In this connection reference is made to Finnish patent No. FI-116538 of the applicant .

Figure 8 shows one example of a web forming machine being now more particularly a paper machine 37. The paper machine 37 is formed of several successive sections, such as, for example, a headbox 49, web forming section, press section, and dryer section 50 - 52. A calendering section 53, for example, can be located prior to the reel 54. All this is monitored and con- trolled with processing unit means CPU. More particularly, the processing unit means CPU can be understood as machine control and condition monitoring automatics 100 - 105.

The sensor assembly 12 according to the invention, arranged in rotating elements, such as, for example, rolls 10.1 - 10.5, can be connected to the processing unit means CPU. Together they can form a system for monitoring and/or controlling the operating conditions of a rotating unit, such as, for example, a roll 10.1 - 10.5, of a web forming or finishing machine 37, 42. The method can be derived directly from the system, which represents only one implementation method for the practical realiza-

tion of the basic idea. In the machine, at least part of the rolls 10.1 - 10.5, such as, for example, their bearing and/or loading means 11.1 - 11.3, 114, 115, 35, 36, may have been equipped with thin-film sensor means 12. These can provide actual measurement results to the processing unit CPU related to at least one measuring parameter. As a submodule, a monitoring module 100 including data transfer links 205 can be harnessed to take care of this. For the monitoring of the sensor 12, it is possible to apply, for example, a Wheatstone type bridge circuit with amplifiers and sealers.

According to a first embodiment, the sensor means 12 can be used to monitor the condition of bearings, such as, for example, roller/slide bearings 11.1, 11.2, 11.3 (module 102). In the condition monitoring of the bearing 11.1, 11.2, 11.3, the thin-film sensor 12 can detect a problem condition even before the actual damage has started to develop. An exceptional loading distribution or load/temperature level indicates an abnormal event and thus provides an opportunity to correct the condition and prevent or delay the development of damage. The sensor assembly 12 is connected via the automation CPU to monitor the condition of the bearings 11.1 - 11.3.

An example of a problem related to condition monitoring, in which the invention can be applied, can be caused by a roll length change due to thermal expansion. This change can lead to a disturbance in the operation of the bearings 11.1, in case the axial sliding fit 43 between the bearing 11.1 outer race 16 and the housing 31 does not function as designed (Figure 6) . This can be due to, for example, sticking caused by the micro- movement of the sliding surfaces. As a consequence of the phenomenon, loading increases intensively on the second roller race of the bearing 11, which is undesirable as regards the calculatory load of the bearing. The sensor assembly 12 detects the disadvantage in loading allowing consequently the nip to be opened. By applying temporarily low load values the friction

force subjected to the sliding fit reduces, permitting the bearing housing 31 and the outer ring of the bearing 11 to move proportionally to each other, and the bearing 11 returns to its "place". After this, the nip can be closed again and it is possible to return to the desired load values.

According to another embodiment, the sensor assembly 12, 100 according to the invention can be harnessed for the optimization of lubrication of bearings 11, such as, for example, roller bearings 11.1, 11.2 and/or, on the other hand, of slide bearings 11.3, 114, 115 as well. In the present adjustable circulation lubrication system 101, 300, the set point of the lubrication oil flow of the roller bearings 11.1, 11.2 is calculated according to the calculatory maximum load and the machine's actual running speed. In bearings 11.1, 11.2 equipped with thin-film sensors 12, the regulation of the lubrication oil flow can be controlled based on actual operating values

(load and temperature, or just one of them) . The target is to keep the bearing 11.1, 11.2 temperature within certain limits with a correct oil flow.

Thus the processing unit CPU, 101 can be used to control the oil flow regulation of the bearing means 11.2, 11.2 of the roll 10.1 - 10.5 (regulation means 41) based on the measurement performed with the thin-film sensor means 12. A lubrication film failure causes a temperature and pressure peak (load) . With the sensor assembly 12 it can be detected at an early stage before the development of damages, and corresponding alarms can be activated.

According to a third embodiment, using the thin-film sensor means 12 it is also possible to determine loads focused on the bearing means 11.1, 11.2. The load information is revealed by calculating it based on the pressure information provided by the sensor assembly 12. One application for this can be a 0 load elimination system for the roller bearing 11.1, 11.2. A

criterion value can be set for the loading. Upon its fulfilling, a low axial load, as per the set value, can be focused on the bearing means 11.1, 11.2.

By utilizing thin-film sensors it is also possible to build an active loading system 104, 20 in the bearing 11, which can be used to eliminate the development of any overload. For example, thin-film sensors 12 can detect an overload at the second roller race 19.2 or even a condition indicating an approaching overload. In case the pressure measurement of the thin- film sensor 12 indicates a load increase to a critical area on the second roller race 19.2, for example, the position of the fixed race of the roll bearing is moved in the axial direction. For example, the movement can be directed to the roll's free end. This movement provides a uniform load distribution to both races. Feedback to the control of the movement can be designed based on, for instance, the bearing pressure, which is measured with the sensor 12.

Figure 9 shows one application example of such an active loading system 20 in the bearing means 11. Now, associated with the free end of the roll, there may be included actuators 20 for loading the fixed race 16 of the roll bearing 11 in the axial direction based on a loading determination made with thin-film sensor means 12. The actuators can consist of hydraulic cylinders 20 or electric transfer screws, for example. The actuator/s 20 can be connected to the bearing race 16 symmetrically to three points, for example.

Further, according to a fourth, embodiment, the thin-film sensor means 12 can also be used to measure the nip forces (linear load) of roll nip constructions 45, for instance, in roll nip constructions 45 fitted with roller or spherical plain bearings

(Figure 7b) . For example, force measurements can be performed at the fixed races 15, 16 of the bearing means 11.1, 11.2. Based on the measurements it is possible to adjust and control

the calendering process in intermediate or deflection-compensated rolls (for example, the SYM roll type developed by the applicant) . Thus the invention enables a more extensive use of rolls mounted with roller bearings in calenders 42, 53. 5

Also in multiroll calenders 42, with the invention it is possible to measure/determine loads of rolls mounted with antifriction bearings (intermediate rolls and deflection-compensated SYM rolls) . With this, nip forces (linear load) ap-

10 plied at each moment can be accurately revealed and in addition, it is possible to prevent the bearing load from drifting to the 0 load zone. Earlier, it has been possible to estimate the linear load as a total, whereas now even the nip profiles can be dealt with. Besides the hydraulic loading elements 35,

15 36, the profiles can be measured even on the surface of the roll shell 13, which can also be equipped with a sensor assembly 12 according to the invention. With the invention, it is possible to take into account also the earlier unknown friction forces focusing on the roll stack 10', such as, for example,

20 forces generated by lever mechanisms and deflection-compensated zone-controlled rolls.

Further, according to a fifth embodiment, a thin-film sensor assembly 12 according to the invention can be applied even in

25 load measurements taken over the sliding surfaces 38 of the slide shoe 39 of the press 51 belt roll 10.4 and/or at the pockets 38' of its slide shoes 39. This application is illustrated in Figure 10. Located within the rotating shell 10.4' of the belt roll 10.4 there are loading means 40, which are used

30 to load the shell 10.4' against the counter roll. The arrangement can be used to measure actual loading pressures and/or temperatures. The linear load measurement is also more accurate than before when the sensor assembly is placed in the shoe 39, for example. The sensor assembly can comprise several sensors

35 12 in the loading element 39 at uniform intervals, for example.

This measurement can also be connected to the machine automation/condition monitoring (module 104).

Further, according to a sixth embodiment, the sliding surfaces of the slide bearings 11.3, 114, 115 and the slide shoe pockets/cavities 61, 62, 64, 65 can also be used to measure the actual bearing load pressures and temperatures with a thin-film sensor assembly according to the invention. Furthermore, this solution, too, can be applied in production machines for condi- tion monitoring. In the slide bearing applications 11.3, 114, 115, the surface pressures are lower than in the antifriction bearing applications 11.1, 11.2. In the slide bearing applications 11.3, 114, 115, however, problems are created by friction and wear particularly at disturbances.

Measurement and control solutions based on thin-film sensors offer several significant advantages in the paper machine environment. Firstly, it provides more freedom for arranging the measurement. Now it is possible to measure the pressure and temperature of such objects as well, which for some one or several reason cannot have been measured earlier. Measuring the pressure and/or temperature is enabled without the sensor assembly disturbing the rest of the equipment or machine operation. The sensor is very simple to implement. A pressure mea- surement carried out with the sensor assembly 12, 12' provides access to loads/forces .

As can be established based on the above, thin-film sensors 12 can be used in very many applications in the web forming and finishing machine environments. The sensor assembly solution according to the invention provides new possibilities for measuring the pressure and temperature also due to its dimensions. For each measurement, the sensor can be dimensioned for the particular measurement. The dimensioning can be influenced, for example, by the material selections and/or thicknesses of the sensor 12.

One example of a sensor 12, such as can be applied in the invention, is 1 - 15 μm, more particularly 4 - 8 μm, such as, for example, 5 - 6 μm, given as the total thickness. Naturally, thinner sensors are also possible provided that they can offer sufficiently sound isolating films. The surface area of an individual sensor 12 can be 0,5 - 5 mm 2 , for instance. To provide one example of the diameter of a circular sensor design, for example, a diameter of about 1 mm can be mentioned. As exemplifying pressure resistance, in the slide bearing applications 11.3, 114, 115, for example, the sensor's pressure resistance can be 40 — 150 Mpa, and in other applications, when the basic material is steel, as high as 1,5 GPa. To give an example of roller bearing 11.1, 11.2 pressures appearing in the paper machine 37, the highest surface pressure is 1.4 GPa in special cases, however 0.6 - 0.8 GPa in average.

One exemplifying manufacturing method for the sensor assembly according to the invention is, for example, a surfacing procedure including one or more stages implemented on the metal surface of the bearing 11. As examples of suitable deposition methods, industrial surfacing methods known as such can be mentioned, such as, for example, sputtering and/or sensor layering arranged with atomic layer techniques (for example, ALD surfacing method, atomic layer deposition) .

Figure 11 provides an example of such a covered layer construction shown as a cross-sectional view. Here the thin-film sensor 12 is within a coating with a rigidity and hardness corresponding to at least metal A. The' sensor 12 has thus a hard protec- tive layer, which is now ceramic or of "kelmet" (ceramic metal), for example, in which case its surface pressure resistance is notably better than that of strain gauge transducers, for example. The sensor 12 also enables measuring pulsating load, which can appear in the paper production environment . The layers and their exemplifying film strengths are: base A (= bearing metal) , such as aluminum alloy or kelmet film; interme-

diate film B (Cr or Ni-Cr 0.1 - 0.8 μm) ; isolating film C (SiO 2 , 2.4 μm) ; sensitive sensor film D (Cu-Mn-Ni, 0.15 - 0.3 μm) ; conductor film E (Cu-Mn-Ni, 0.15 - 0.3 μm) , and protective film F (SiO 2 , 2.4 μm) . Further, it is to be understood that the sensors 12 shown in the figures are extremely exaggerated as to their dimensions for illustrative purposes. In reality, the sensor assembly 12 is a part of the surface of the component 11, 35, 36, i.e. integrated thereto. Thus the sensor assembly 12 and the component 11, 35, 36 form a jointly functioning entirety.

Generally, a sensor according to the invention can be based on the piezoresistivity of manganin (an alloy metal of copper, manganese and nickel) . The shape of the sensor assembly on the surface or in the vicinity of it can be an arc (arc) or omega (ω) , for example.

It is to be understood that the above description and the figures related thereto are only intended to illustrate the present invention. The invention is thus not limited to merely the above described embodiments or those set forth in the claims, but many different variations and modifications of the invention, which are possible within the boundaries of the inventional idea specified in the appended claims, will be apparent for one skilled in the art.