FI123251B - Method and arrangement on a fiber web machine and software product - Google Patents

Description

METHOD AND APPLICATION WITH FIBER MACHINE AND SOFTWARE PRODUCT

The invention relates to a method on a fiber web machine, which method changes the position of the fabric Karvi to minimize the vibration level of the fiber web machine 5. The invention also relates to an arrangement on a fiber web machine and a software product.

The direction of the web used for the fiber web machine is changed by moving one end of the roll in the web. At 10 causing the transfer of the fabric treatment path difference and the drive side, wherein the edges of the tissue are different from the distances traveled. In this case, the tissue is slightly stretched and skewed. Usually, the direction of the seam of the fabric, i.e. Karvi, is further marked on the fabric by a streak. In this case, changing the orientation of the track is also called turning Karvi. In press fabrics, the seam is either the seam of the manufacturer or the factory seam. One Karvin translator is disclosed in Applicant's Finnish Patent 116399. Here, the Karvin translator also controls tissue. With a press, the fabric is usually a thicker press felt. The junction of the press felt 20, i.e. the Karvi, is attempted to be rotated so as to prevent the average Karvi from entering the press nip at the same time. By turning the curve, any depressions are thus formed indefinitely and in different positions on the press felt, thus avoiding strong vibrations and repetition of the depressions. 25 At the same time, the life of the press felt will be extended and the vibration level of the fiber web machine will be reduced.

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Nowadays, the hair flipper is used back and forth while at the same time the oscillation level of the fiber web machine is monitored. In practice, however, the movement of karvin-30 translators is based on experimentation alone

Er drive to the models. In this case, the setpoint is assumed to remain

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0 true. In reality, the position of the directional track and at the same time Karvi

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o and hair setter setpoints are poorly matched and ^ corresponds to changes in fiber web machine changes, such as

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35 why. In this case, previous, purely experimental driving patterns from the hair follower's place to damping vibrations are invalid. Thus, with new tissue, the method of driving 2 must be experimentally re-taught. Learning takes a long time, and in the worst case, the right way to drive is not found when the tissue has to be replaced. Typically, the Karvin translator position is continuously oscillated over a short period of time, for example, only ± 7 mm. In this case, by observing the vibration level, the effect of the pivoting on the vibration level of the fiber web machine remains unclear. In addition, measurement based solely on vibration measurement really starts to work only after the vibration has started. In other words, the tissue or nip roll is already partially damaged 10 or at least deformed. In the worst cases, the press fabric or roller has had to be replaced due to vibrations. In a randomized example, the life span of a single tissue has been between one and twenty-one days. Thus, the lifetime dispersion has actually been high. In practice, tissues have generally had to be replaced precisely because of vibrations and the resulting deformation of the tissue, despite vibration monitoring.

It is an object of the invention to provide a fiber web machine 20 with a novel method of maintaining a low vibration level of a fiber web machine. A further object is to provide the fiber web machine with a novel arrangement which is suitable for different fabrics and which operates in spite of changes in the web or fiber web machine. It is a further object of the invention to provide a novel software product suitable for a variety of fiber web machines that can be used to control a tuftter. Characteristic features of the method V of the present invention are that the Karvi position is determined by the width of the tissue. Correspondingly, an arrangement according to the invention

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A feature of £ 30 is that the arrangement further includes o sensor means for determining tissue width. invention

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The method according to cd accurately determines the position o of the Karvi and its correspondence to the vibration level of the fiber web machine. Here

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vibration sensitive areas can be avoided and thus 35 vibrations are avoided. The arrangement is simple and reliable without complicated equipment. The software product is easily 3 connectable to existing fiber web machines and in particular to hair curlers.

The invention will now be described in detail with reference to the accompanying drawings, in which:

Fig. 1 shows a part of a press section of a fiber web machine equipped with an arrangement according to the invention, Fig. 2 shows the principle of pivoting,

Figure 3 shows the correlation of the tissue width to the vibration plane with a fiber web machine,

Figure 4 shows the correspondence of the hair follower position to the width of the fabric on a fiber web machine.

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Figure 1 shows a press section of a fiber web machine. In this concept, there are two press nipples, the upper one being formed between two rolls 10 and 11. A press fabric, more generally fabric 12, supported by 20 guide rolls 13 and 13 'is also guided through said press nip. The arrangement also includes a sutured and thus Karvian 14 woven fabric 12 (Figure 2). The direction of the hair is often marked on the tissue also by the streak. The arrangement further comprises moving means 15 for changing the position of the karv 14 and measuring means 15 'for determining the position of the moving means 15. In Figure 1, the actuating means 15 and the measuring means 15 'are integrated into the tissue clamp 17. The measuring means detect the position of the actuating means in its operating area. With the moving means o V the end of the roll can be displaced for example ± 7 mm.

sfr x £ 30 The arrangement may further include detection means 16 for determining the vibration level of a fiber web machine. The detection means § may consist, for example, of vibration sensors o located at the end of the roll or on the shaft. The vibration level can be

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for example, also determines the loading pressure of the nip roll. 35 In addition, a hand-held meter can be used, in which the vibration is monitored only occasionally.

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Fig. 2 shows the movement of the guide / tensioning roll 13 'for turning the Karv 14, which is thus preferably in the direction of motion of the fabric tensioner. With the guide / tensioning roll 13 'straight, the hair 12 of the fabric 12 is also generally straight. These 5 straight Karvs are represented by a dotted dash. As shown in Fig. 2, when one end of the guide / clamping roll 13 'is moved to the left, the other edge of the fabric 12 is stretched while at the same time turning the entire fabric 12 at an angle. In this case, Karvi 14 will also be skewed, which is desirable. However, in this case, the fabric 12 tends to move toward the shorter edge, i.e., upwards in Figure 2, as illustrated by an arrow. The lateral movement is compensated by the tissue guide 21, whereby the tissue remains at the desired position despite the hair turn.

In order to operate the assembly, the moving means 15 and the measuring means 15 'are connected to the control means 18, to which also the detection means 16 are connected. The control means may be separate programmable logic devices or the control means may be part of a machine control system 18. According to the invention, the arrangement 20 further comprises sensor means 20 for determining the width of the fabric 12. The moving means 15, the measuring means 15 and, in the embodiment shown, the observation means 16 and the sensor means 20 are connected to the control means 18, which are represented by dotted lines. In practice, the arrangement changes the position of the Karvi 14 within the fabric 12 to minimize the vibration level of the fiber web machine. However, the invention utilizes

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, surprisingly, the fabric itself, more specifically its width for determining the Karvin o L "position. In other words, according to the invention, the Karvin 14 M" position is determined by the width of the fabric 12. In this case, despite the change in tissue x £ 30 or other changes in circumstances, the position of the Karv is known with sufficient accuracy. Therefore, Karvia C \ 1

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the cd can be rotated in a safe area without vibration levels rising. In practice, the Karvi direction of the tissue is recognized

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tissue width and orientation information are utilized to eliminate nipple and tissue vibrations.

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The method monitors the width of the fabric 12, thereby avoiding a situation where the fabric 12 is at its widest. Once the Karv's position and vibration level are known, an analysis of their correspondence can be made. Based on the analysis it is possible to calculate the correlation of the hair follower's position with the width of the tissue. For example, second-order regression analysis may be used as the basis for an accurate response in the tests. In the exemplary analysis, the maximum of the regression line corresponds to the location of the hairpin, with maximum tissue width (Figure 3). 10 Analysis can be done in different ways. Preferably, the analysis is performed immediately after a maintenance outage by driving the hair follower once across its entire range of motion. The analysis can also be performed after the first analysis at all times while driving, with the hair follower moving. In other words, the determination of equivalence, i.e., correlation-15 analysis, is performed both after tissue replacement and when using tissue. Also, as other circumstances change, it is easy and quick to repeat the analysis.

Preferably, only a plurality of possible new 20 measurement points are included in the analysis. In other words, it is preferable to use a relatively small but fresh set of measurement points for analysis. In this case, the set of measurements and the analysis made thereof will best represent the prevailing conditions and the effect of tissue width variation due to tissue aging will be avoided. In practice, for example, the width of the tissue changes slowly as the tissue ages. With a small set of measuring points c \ i, the measuring points are placed exactly in the correlation line.

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In addition, it has been found in the tests that an analysis period of three days already contains too much and too old x £ 30 measurement data. By shortening the analysis period and frequently repeating the analyzes, the correlation response remains accurate.

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o Based on the analysis, it is possible to determine the position of the hair follower

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correlation with the measured vibration level over the lifetime of the respective tissue 35. In practice, vibrations can be avoided by moving the hair follower in an area where the oscillation level is low at the eyelids. In other words, the most sensitive area of vibration is avoided by defining the harmful area at its simplest from a point on the perpendicular Karvi in each direction. Thus, the position of the Karv translator can be changed to eliminate vibrations in a region other than 5 perpendicular Karvs. Changes can be continuous oscillation or the hair follower is moved at appropriate intervals. Preferably, the equivalence is determined by changing the position of the Karv while simultaneously measuring the vibration level. This will provide up-to-date information on equivalence.

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Figure 3 shows graphs of test measurements on a fiber web machine. Herein, the assay of the invention is performed in a short time period of three days. In this case, the hair follower position correlates very well with the width of the tissue. Likewise, the measured vibration levels correlated very well with both the width of the tissue and the position of the hairpin. It is also noteworthy that one can see very clearly in the graph that the vibration level is higher the closer one is to the straight Karvi. In fact, the ratio of tissue width to 20 levels of vibration is astonishingly unambiguous and clear. Similarly, the shape of the calculated correlation lines and their maxima are virtually identical to each other. Light dots are vibrational levels of the nip roll drive side bearing housing. These readings are on the Y-axis and are in mm / s2 with readings ranging from 0.5 to 1.0. The dark dots are the actual widths of the tissue measured. These readings are also on the Y axis and

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, their magnitude is mm, with readings varying 70. For both measured readings, second order correlation lines are also calculated whose shapes correspond to each other. In the common law of correlation lines x £ 30, the width of the tissue is at its maximum, and thus o Karvi is perpendicular, whereby also the vibration level is at its highest. At this point, the hair follower position is about -3.75 δ mm. The position readings are on the X-axis and are in mm

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readings within ± 15 mm. Based on the analysis, 35 of these hair rotators can be oscillated, for example, at intervals of -12.0 to 7 -8.0 or 2.0 to 7.5. The point -3.75 mm can also be skipped as long as the area in question is as short as possible.

Figure 4 shows the correlation of the hairpin translator site to tissue-5 width. This correlation is very good and accurate. The most accurate analysis is obtained by analyzing the Karvin translator when moving in a direction in which the tissue is expanding. Thus, as the hair follower position changes, the width of the tissue closely follows the hair follower position 10 change. The staircase illustrates the position of the fur translator. The position readings here are on the Y-axis and their magnitude is mm, with readings ranging from -6.0 to 9.0. The envelope is proportional to the width of the fabric based on this operation and use half the sum of the measurements. The relative width readings here are on the Y axis and have a value of 15 in mm with readings ranging from 55.0 to 85.0. As the tissue spreads, that number decreases.

In practice, the hair follower can be oscillated on either side of the affected area alternately. From one side to the other 20, it is possible to move smoothly with the web in the case of the margins because the fabric runs at its widest when crossing the straight Karv. During the transition from side to side, a new correlation analysis can be performed on the correlation of the hairpin translator position to the tissue width. Therefore, it is a good idea to perform the new correlation analysis as often as possible. The correspondence between the hair position and the vibration level of the fiber web machine can be determined even substantially without interruption. Frequent or continuous analysis o "V can effectively eliminate, for example, the effect of aging tissue width change, slip load, amount of water, or any other phenomenon changing the width x x 30 of the tissue. In addition, even if one side to another is omitted, preferably continuously. No side to another after the transition to the earlier analysis result is rejected c \ i entirely. In this case, a different side forms a transition to a new set of measurement points 35, which corresponds to the new edge conditions.

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It has also surprisingly been found in the tests that the most accurate analysis is obtained when the hair follower moves in the direction in which the tissue widens. In other words, matching is determined as the width of the tissue increases as the Karvi changes position.

5 In this case, as the position of the hair follower changes, the width of the tissue closely follows, with as little delay as possible, the position of the hair follower. Surprisingly, it has been found that the tissue tends to resist turning the Karv away from the perpendicular and thus spreads faster than narrows when turning the Karv. When moving 10 from one side of the perpendicular to the Karvi, the location of the Karvi translator is selected so that the Karvi is as far away from the wavelength of the previous position and its harmonic multiples as possible. This will ensure that the hair follower's operating range is safely far enough away from the harmful area. 15 Knowing exactly the perpendicular position of the Karv with the maximum tissue width, it is easy to calculate the Karv angle a. For the respective tissue width from the equation L.

arccos & = - 2 g where Ls is the current tissue width and Lmax is the maximum tissue width.

By using this Karv angle information, it is possible to try to keep the Karv as far away as possible from the harmonic multiples of the roll and tissue rotation frequencies. Thus, it is possible to prevent 25 levels of vibration from rising before it has even begun. When this is done accurately also for the tissue, a position measurement can also be fitted to the tissue clamp cj. This also provides accurate information on the length of the 0 V fabric when the roll diameter is already accurately known.

1 30 o Also, in press nipples with two fabrics, the position of the hairs of both fabrics can be controlled as described above, o In addition, the entire fiber web machine can be optimized so that the positions of the tissue hairs are as far apart as possible the harmonic multiples are as far apart as possible 9. In other words, the hair positions of the tissues are adapted to opposite angular positions. Further, preferably, the hairs of the tissues passing through the same nip are independently repositioned. In this case, the vibrations due to the interaction between the tissues 5 can be prevented.

Especially with old and modified tissue, the correlation between Karv's posture and vibration level can even be lost. In this case, the position of the hair follower can be optimized solely on the basis of the correlation between the hair follower and its level of vibration. For example, loss of correlation can be observed from residual variance in tissue and vibration level correlation analysis. In addition, it is possible to choose to spread the tissue throughout its life, as far as possible, in order to maintain the runnability of the web edge region 15. Spreading is taken into account when optimizing the Karv angle within the operating range of the Karv translator. Thus, the control system is in fact a learning system and adapts to changing circumstances.

20 Various technical solutions can be used to identify tissue width. One simple solution is based on the applicant's UltraEdge sensors, which are positioned on both sides of the tissue. Ultrasonic sensors detect tissue edges and can thus determine tissue width from measured values. Similarly, with an electromechanical tissue guide equipped with UItraKdge sensors £, the edge measurements are already complete with the fiber web machine, so that the necessary investment remains small. In its simplest form, the prevention and minimization of oscillations can be done even on the basis of measurement of tissue width x £ 30 without vibration measurement.

o This further simplifies the structure of the mediation, o

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o Other possible techniques for determining tissue width include, for example, mechanical elements, but also ultrasound, visible light, ultraviolet light, infrared light, laser, and image recognition, i.e., applications that detect tissue edge reflection and edge 10. Single tissue analysis can also be used on new tissue with at least some accuracy. In such cases, it is not always necessary to carry out the analysis. However, the analysis is done after addressing issues affecting the alignment of the fabric 5 in the fiber web machine such as changing rolls or tissue type. In other words, without major modifications to the fiber web machine, it can be assumed that the widest, or most oscillating, point is in the former position, which is known to stay away from it. If the situation of the direct direction strip is avoided once 10, the first excitation of the direct direction strip is avoided. The analysis can even stop the constant, frequent and unstoppable movement of the hair follower. Instead, optimized and periodic hair rotations can provide even better results than 15 continuous movements. With the tissue remaining in place for a longer period of time, a more consistent end product can be obtained, with the nip and tissues working properly without vibrations.

By the method of the invention, the position of the Karv 20 in each operating range of the Karv translator is determined. In this case, the control of the mediation is based on observed values instead of experimental or statistical values. This systematically utilizes the resulting set of measurement points which, when analyzed, yield the correlation used for control. In this case, it is possible to be aware of the 25 current operating ranges of the hair rotator, where the vibration levels ^ are known to be at their lowest. In other words, the arrangement o ^ provides information on the usable operating range and its response to vibration even before the vibration has risen.

st £ 30 In practice, the directional lines are never completely straight, but can be, for example, an S-bend, a C-bend or just a local bend.

C \ 1 § In this case, the position o of the alignment measured only at the ends of the Karvi would give an incorrect representation of the mean angle of the Karvi.

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However, determining the position of the Karv over the width of the tissue provides 35 simple and, above all, sufficiently accurate information.

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Figure 1 shows in principle the control of the arrangement. The hair control translator 15 is connected to a machine control system 19 to which sensor means 20 is also connected. The machine control system is a software product comprising software code elements arranged to carry out the above steps of the method according to the invention.

Due to the method and the arrangement, the life span of the tissues is substantially prolonged when the premature need for tissue replacement due to vibration can be prevented. The service life extension achieved is significant, especially in hard roll nipples and single presses, where fabric deformation is strongest. Significant savings can be achieved by eliminating vibrations and warping of the tissue and roll, since the lifespan of the fabrics 15 is invariably extended up to weeks. In other words, oscillation problems can be largely avoided, regardless of position and tissue, without randomness. In other words, the rise of the vibration level can be prevented even before it has begun. By keeping the vibration level low, 20 vibrator-sensitive loading areas can be used in the past to further influence the quality of the end product. In addition, production can be carried out at significantly higher speeds, which means an increase of more than 10% in production.

The insight in accordance with the invention recognizes the position of the Karv over the width o of the tissue, allowing the use of simple and robust component paths V. In addition, the Karv's position is determined without delay when sensing tissue behavior, more specifically x £ 30, as the width changes as the Karv's position changes. In practice, the width of the tissue expresses, in particular, the average Karvin co position very precisely. In other words, the width takes into account as much as possible the error caused by the Karvi o indirectness. In addition

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the results of the analysis are obtained quickly, depending on the application 35, the analysis takes half an hour to two hours.

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The method can be implemented in practice, for example, as follows. When a new tissue is introduced, the position / position of the tuft rotator with the tuft parallel to the nip will be searched for by the width of the tissue. During operation, it is avoided to get to that 5 hair follower position / position and too close to it. In other words, the nipple Karv is avoided. If necessary, the maximum tissue width is searched for during operation by moving the hairpin from one side to another. Hereby, the current tissue width and maximum width measured are obtained as the Karv position 10, i.e. the angle of rotation. In addition, by comparing the positions / positions of the current rotator corresponding to the current Karv, the sign of the turning angle is known. Based on the angle of rotation, the Karvia of the tissue can be guided by moving the rotator so as to avoid multiple rotations of the roll and felt. The correlation between Karvin-15 translator position / position, Karvin position, and vibration level can be continuously calculated.

Typically, the roller and the tissue guide affect different rolls. In other words, by properly moving the two rollers 20, both the turned Karv and the guided tissue can be moved as desired. The roller, and thus the roller affected by it, can be held in place in the preferred area for a longer period of time as the other end of the guide roller is slowly driven in the same direction by the automation. From this it can be concluded that Karvi will continue its 25 movements despite the fact that the Karvari roller is stationary.

^ This prevents the generation of vibrations that would occur

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^ with stationary hair over time, regardless of the position / distance of the Karvi o V directly to the hair. The hair roller roller may be in place for days, however, as the vibrations are constantly decreasing. It can be deduced from this that the position of the Karvi changes slowly due to the action of the guide roller. Thus, it is advantageous

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§ also monitor the movement of the guide roller, preferably its trend.

5 It is then known in which direction Karvi is turning. Otherwise

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that is, the movement of the guide roll can be used as a secondary indication 35 for controlling the entire system.

Claims (10)

A method of a fiber web machine, according to which the method of positioning the web (12) of the web (12) is changed to minimize the level of vibration of the web web, characterized in that the position of the web (14) is determined by the width of the web (12). 2. A method according to claim 1, characterized in that according to the method, the width of the web (12) is followed and / or the position of the moving devices (15) used to move the position of the web (14), as a situation where the web (12) is avoided. ) is at its widest. Method according to claim 2, characterized in that the correlation between the position of the joint (14) and / or the displacement devices (15) and the vibration level of the fiber web machine is determined substantially continuously. Method according to claim 3, characterized in that the determination of the correlation is carried out both after the replacement of the web (12) and during the use of the web (12). Method according to claim 3 or 4, characterized in that the correlation is determined by changing the position 25 of the joint (14) and simultaneously measuring the level of vibration. OJ δ (M 6. A method according to any one of claims 3-5, characterized in that the correlation is determined when the width of the web (12) increases at 0X1, a change in the position of the web (14). £ 30 o Method according to any of claims 1-5, characterized in that the position of the joints (14) in the weaves (12) that like to change through the same nip independently of one another. Method according to claim 7, characterized in that positions! the joints of the weavers (12) are arranged at opposite corner positions. Arrangements in a fiber web machine, which include spliced web (12), displacement devices (15) for changing the position of the splicer (14), measuring devices (15 ') for determining the position of the displacement devices (15), and control devices ( 18) coupled to displacement devices (15) and to measuring devices (15 '), characterized in that the arrangement further comprises sensor devices (20) for determining the width of the web (12). 15 10. Software comprising program code elements, characterized in that the program code elements have been arranged to execute the steps in a method according to any of the above claims 1-8. C \ l δ CM ιό o st CM X cc CL O CM O CD δ CM