A two-drum winder

Abstract

 The present invention relates to a two-drum winder for winding partial webs (10) for a fibrous web comprising at least two surface support elements (15, 20) to support a web roll (25) from below and a rider roll (30) which is arranged to support said web roll (25) at least for part of the forming time of the web roll above it. The rider roll (30) is provided with a tuned torsional vibration absorber (40) arranged to attenuate rotational vibration of the rider roll such that the machine directional concurrent vibration of the web roll is attenuated via tangential force interaction between the riderroll (30) and the web roll (25).

Description

[0001] The present invention relates to a two-drum winder for winding partial websaccording to the preamble of claim 1 for reducing machine directional vibrations in a partial web winder of a fibrous web.

[0002] As is known in prior art, in a slitter-winder the machine roll is un-wound and the wide web is slit with the slitting part of the slitter-winder into a number of narrower partial webs that are rewound with a partial web winder to form customer rolls. When the customer rolls being simultaneously made from each partial web are ready, the slitter-winder is stopped and the partial web rolls are removed from the machine, i.e. the set change is done. Subsequent to this the process is continued as winding of a new set of rolls. These phases are repeated in sequences until the machine roll runs out of paper, whereby the machine roll is changed and the operation is started again as unwinding another machine roll. The partial web winder can be a two-drum winder in which the partial web rolls are wound carried by winding drums, typically supported by a rider roll from above.

[0003] In winding, e.g. when winding a paper web with a slitter-winder, large vibrations occur in certain paper types at same roll rotation frequency ranges regardless of the running speed of the slitter. Usually there are about 1 to 3 vibration ranges, i.e. rotation speed ranges of the roll on which there is strong vibration, depending on the final diameter of the roll. This strong vibration causes winding reject, mechanical wear of the apparatuses, even loosening of the roll from the winding apparatus as well as decrease of winding capacity as the running speed has to be lowered during winding.

[0004] FI101283 discloses a method in which the running speed of the winder is controlled based on the rotation frequency of the roll so that as the rotation frequency of the roll approaches the vicinity of the vibration range, i.e. the roll rotation frequency range where there is a strong vibration, the running speed is quickly lowered so that the rotation speed of the roll decreases to below the lower frequency of the vibration range and subsequent to this the running speed is increased so that the rotation frequency of the roll remains constant until the original running speed of the winder is reached. Due to the change of the running speed this has an effect on the total capacity of the winder.

[0005] As the size of the partial web rolls increases during the winding, at least the rider roll is moved to compensate the growth of the diameter of the rolls. Thus at least the rider roll arrangement is movably supported by the body structure of the winding part. The consecutive longitudinal rolls are locked in their places as a line of rolls by means of a core locking device arranged at both ends. The support means contacting the roll (or rolls) to be wound are exposed to the dynamic load caused by the rotating roll. Especially in connection with two-drum winders there occur dynamic loads causing vibration especially in the rider roll and the supporting rider roll beam, excited by the partial web rolls to be wound. It is also typical for the process that the diameter of the roll to be wound has an effect on the vibration of the rider roll. Thus the vibration conditions change as the winding proceeds.

[0006] The design aim of the rider roll of a slitter-winder is a stable construction able to withstand dynamic load. A generally used practical solution is one in which rider roll segments are suspended from a relatively rigid rider roll beam. The rider roll beam is moved along two or more guides attached to the body. The guides are located near the ends of the beam.

[0007] A particular form of vibration occurring in a two-drum winder is machine directional concurrent vibration of the rolls in the set. In a slitter-winder of the two-drum type, the whole set or single rolls can start to oscillate typically on a relatively low frequency (about 5 - 15 Hz) in the machine direction on top of the winding drums. The phenomenon can limit the maximum speed usable in winding, thus decreasing capacity. In the worst case, the phenomenon can cause the off-throwing of the set.

[0008] Specification US4180216 presents as a solution for the problem transferring the rider roll during winding along the surface of the web roll from its peak point as the web roll increases with the purpose of changing the spring constant of the web roll being completed. The specification also suggests using several rider rolls simultaneously to support the set. The adjustment of the position of the rider roll is described occurring pre-programmedly based on experience and the roll diameter of the set being completed, among others. With this type of an arrangement, it is in practice not possible to prevent the phenomenon sufficiently, because actual conditions in winding are always different from the ones of a previously compiled statistical model.

[0009] With certain fibrous-web types, the forming of partial web rolls can be achieved more advantageous if the rider roll is provided with a drive. Then, it is possible to apply moment/force, i.e. pull, to the surface of the web roll with the rider roll. Publication EP2108606 A2 describes a two-drum winder in which the rider roll unit comprises a drive. More particularly there is disclosed a two-drum winder which comprises at least two surface support elements of the roll arranged to support at least one roll being formed substantially below it and at least one loading device which is arranged to support said roll at least for part of the forming time of the roll substantially above it. The winder comprises also at least one drive so that the drive is arranged to apply tangential force to the roll being wound and a control arrangement which is arranged to control said at least one drive of the two-drum winder so that the drive provides the roll being wound with an effect diminishing the machine directional concurrent vibration of parallel rolls, which in this case is machine directional concurrent vibration of the rolls in the current set. In order to operate in acceptable manner the drive must be of considerable power and the system requires somewhat sophisticated controlling system..

[0010] Object of the invention is to provide such a two-drum winder by means of which the machine directional concurrent vibration of the rolls is at least minimized in a straightforward manner.

[0011] The objects of the invention are mainly achieved with a two-drum winder for winding partial webs according to claim 1.

[0012] Unless more particularly defined, in this context the following definitions are valid. A two-drum winder refers to a web winder in which at least one roll being formed is supported below the roll with at least two surface support devices of the winder, such as a roll or a set of belts supported by rolls. The cross direction refers to the direction of the longitudinal axis of the surface support device, such as the roll, and the machine direction the direction perpendicular in relation to the cross direction and the vertical direction. A set refers to a set of partial web rolls being wound simultaneously on the winder. A roll refers to one or more rolls. Above and below refer to the upper side and under side of a horizontal plane passing via the centre of the roll. Belt means a belt, chain or any other endless power transmission loop.In this context the term flexible means flexibly in practical sense with an intention of having flexibility and/or flexible element does influence on the dynamics of the rotation of the system.

[0013] Object of the invention are met by atwo-drum winder for winding partial webs for a fibrous web comprising at least two surface support elements to support a web rollfrom below and a rider roll which is arranged to support said web roll at least for part of the forming time of the web roll above it. The rider roll is provided with a tuned torsional vibration absorber arranged to attenuate rotational vibration of the rider roll such that the machine directional concurrent vibration of the web roll is attenuated via tangential force interaction between the rider roll and the web roll.

[0014] Thus whenever the setof web rolls is subjected to the machine directional concurrent vibration excitation and would otherwise begin to resonate, the tuned torsional vibration absorberbegins to also resonate at the same frequency and will absorb, or at least damp, the machine directional resonant vibrations of the web rolls.

[0015] According to an embodiment of the invention the tuned torsional vibration absorber comprises mass element which is coupled by a coupling device to the rider roll to rotate along with the rider roll. Advantageously the coupling device comprises a section which is flexible to a predetermined extent.

[0016] According to an embodiment of the invention the coupling device is provided means for changing its flexibility. Changing may be realized so that the torsional vibration absorber may be even turned off and on by changing the flexibility.

[0017] According to an embodiment of the invention the coupling device comprises a torsion bar.

[0018] According to an embodiment of the invention the torsion bar is provided means for changing its flexibility. Changing may be realized so that the torsional vibration absorber may be even turned off and on by changing the flexibility.

[0019] According to an embodiment of the inventionthe rider roll is supported by a beam extending over the length of the rider roll and comprises end walls at the opposite end thereof and the tuned torsional vibration absorber is rotatably supported to the end walls.

[0020] According to an embodiment of the inventionthe tuned torsional vibration absorber is rotatably supported inside the beam. This way the tuned torsional vibration absorber is safely covered by the beam and does not require any extra space.

[0021] According to an embodiment of the invention coupling device comprises belt drive coupling having a first belt wheel connected to the rider roll and a second belt wheel connected to the mass element and a belt connecting the first and the second belt wheels. Advantageously the belt is a flexible belt.

[0022] According to an embodiment of the invention the tuned torsional vibration absorber is arranged adjustable during operation of the two-drum winder.

[0023] According to an embodiment of the invention coupling device comprises belt drive having a variably controllable transmission, by means of which the transmission ratio may be altered during the use of the invention..

[0024] According to an embodiment of the invention the tuned torsional vibration absorber is in power transmission connection with an actuator and that the winder comprises a control arrangement arranged to control the operation of the actuator in response to acquired torsional vibration of the mass element such that the motor actuator synchronized with the mass element increasing the effect of the mass element.

[0025] According to an embodiment of the invention tuned torsional vibration absorber comprises a centrifugal pendulum absorber coupled by a coupling device to the rider roll to rotate along with the rider roll.

[0026] The other additional characteristic features of the invention will become apparent from the appended claims and the following description of the embodiments of figures.

[0027] In the following the invention and its operation are described with reference to the appended schematic drawings, in which

figure 1 illustrates an embodiment according to the invention in connection with a partial web winder of the two-drum type,

figure 2 illustrates a sectional view in the direction A of the figure 1, and

figure 3 illustrates an embodiment according to the invention in connection with a rider roll and rider roll beam,

figure4 illustrates another embodiment according to the invention in connection with a rider roll and rider roll beam,

figure5 illustrates still another embodiment according to the invention in connection with a rider roll and rider roll beam,

figure6 illustrates still another embodiment according to the invention in connection with a rider roll and rider roll beam,

figure7 illustrates still another embodiment according to the invention in connection with a rider roll and rider roll beam,and

figure8 illustrates an example of operation of an embodiment of the invention.

[0028] Fig. 1 shows a two-drum winder 10 according to an embodiment of the invention. The two-drum winder comprises a front winding drum 15 and a rear winding drum 20as support rolls. The winding drums supportfrom below a set ofweb rolls 25 being wound of partial webs W in the winder in a manner known as such. To support the roll 25 from the abovethere is also arranged a rider roll 30. The rider roll 30 is supported on a rider-roll beam 35. Here the terms above and below refer to the upside and underside of a horizontal plane passing via the centre of the roll. The rider roll may be a single roll extending from the first (front) side of the winder to the second (back) side thereof or it may be constructed of several interconnected roll segments. The interconnection means that the roll segments are rotatable connected with each other.

[0029] The winding drums 15, 20 of the two-drum winder 10 are provided with drives 15.1, 20.1 by means of which surface draw i.e. tangential force can be applied to the roll being formed. The rider roll 30 may also be provided with a drive, even if not shown here.

[0030] Fig. 1 schematically shows the machine directional concurrent vibration of parallel rolls which can be at least considerably minimised or even eliminated with the two-drum winder. In the machine directional concurrent vibration of parallel rolls 25, the whole set reference 25' in Fig. 2, moves back and forth in the machine direction from its stable position mainly by rotating alternately on the surface of the front and rear drum 15, 20 as is shown in exaggerated manner in Fig. 1. Individual back and forth motion of single rolls can be minimized by combining successive rolls 25 of the set 25' from their winding centers to each other e.g. by a sleeve 45 which sufficiently locks the centers to each other radially. This can be seen in Fig. 2, which shows section of the two-drum winder of Fig. 1 from direction A.

[0031] When examining the machine directional concurrent vibration of parallel rolls shown by Fig. 1 by way of an example in more detail, it is found that the web rollwill rotate around the winding drum 15 clockwise, motion d1. Then, when rotating, each web roll is pressed with greater force against the rider roll 30. Equivalently, the set will rotate around the winding drum 20 counter clockwise, motion d2. Also from the effect of this motion d2, the web rolls are pressed with greater force against the rider roll 30. Then, nip force momentarily risen on the rider roll also increases friction force between the rider roll 30 and the surface of the web roll 25. The increase of friction force thus occurs at such points of time when via the rider roll 30 the effect of the tuned torsional vibration absorber is to be conveyed to the web rolls of the set 25'. Hence, the arrangement according to the invention is very advantageous.

[0032] According to the invention the rider roll 30 is provided with a tuned torsional vibration absorber 40, which is tuned to a predetermined oscillation frequency of the web roll 25. This way, the in case the machine directional concurrent vibration of the web roll 25 tends totake place, the excitation of the vibration is transmitted into rotational oscillation of the rider roll 30. Depending of the tuning of the torsional vibration absorber 40 the rotational oscillation of the rider roll 30 is reduced and thus the machine directional concurrent vibration of the web roll 25 is minimized accordingly.The tuned torsional vibration absorber is tuned to a frequency at or near which web roll vibration is to be attenuated.

[0033] The machine directional concurrent vibration of parallel rolls affecting the whole set 25' can be minimised when the two-drum winder 10 comprises a tuned torsional vibration absorber 40 arranged to the rider roll 30. The tuned torsional vibration absorber 40 comprises a mass element 42 of suitable form. The mass element is coupled to the rider roll 30 by a coupling device 44 at its rotational axis so that the mass element may rotate along with the rider roll. The coupling device is, or comprises, a section which is flexible to a predetermined extent. In addition the coupling device may comprise a section which is attenuating to a predetermined extent.

[0034] In the embodiment of figure 2 the coupling device is a torsion bar the flexibility of the bar is selected suitably taken into account the mass and the desired frequency to be attenuated. The mass element is coupled to an end of the roll 30 at the centre axis thereof. The rotational stiffness of the bar is selected preferably so that the lowest rotational natural frequency of the bar - mass element system is substantially equal to the frequency to be attenuated.

[0035] In figure 3 there is shown the rider roll and the beam according to an embodiment of the invention in which the tuned torsional vibration absorber 40 is arranged above the beam 35 of the winder. This way it does not require or reserve space on the side of the winder, which is advantageous.The tuned torsional vibration absorber 40 being located at a distance from the rider roll needs a coupling device which facilitates the power transmission between the roll and the mass element 43. Thus the coupling device comprises a belt drive coupling 50 having a first belt wheel 51 connected to the rider roll 30 and a second belt wheel 52 connected to the mass element 42 and a belt 53 connecting the first and the second belt wheels. The belt may be flexible to a predetermined extent so that the tuned torsional vibration absorber may be tuned in appropriate manner.

[0036] In figure 4 there is shown an embodiment of the invention in which the tuned torsional vibration absorber 40 is arranged inside the rider roll beam 35 of the winder. In figure 4 there is also shown how the coupling device 50 comprises a belt drive coupling 50. The belt drive coupling comprising a first belt wheel 51 connected to the rider roll 30 and a second belt wheel 52 connected to the mass element 42 and a belt 53 connecting the first and the second belt wheels. The belt may be flexible to a predetermined extent so that the tuned torsional vibration absorber may be tuned in appropriate manner. The mass element 42 is supported to an end walls 35' of the beam 35.

[0037] In figure 5 there is shown an embodiment of the invention in which the tuned torsional vibration absorber 40 is also arranged inside the rider roll beam 35 of the winder. The coupling device 44 comprises a belt drive coupling 50. The belt drive coupling comprises a first belt wheel 51 connected to the rider roll 30. The first belt wheel is nonadjustable i.e. its diameter is fixed. The second belt wheel 52 connected to drive the mass element 42 is adjustable such that its effective diameter may be changed during the operation and thus the transmission ratio of the belt drive coupling may be changed. The second wheel may comprise means for changing the distance between the opposing inner surfaces of the wheel which, given that the belt has fixed width, changes the radial contact distance of the belt. A belt 53 is connecting the first and the second belt wheels. The belt may be flexible to a predetermined extent so that the tuned torsional vibration absorber may be tuned in appropriate manner. The mass element 42 is supported to an end walls 35' of the beam 35

[0038] In figure 6 there is shown an embodiment of the invention in which the coupling device 44 comprises a belt drive coupling 50. The belt drive coupling comprises a first belt wheel 51 connected to the rider roll 30 and a second belt wheel 52 connected to the mass element 42 and a belt 53 which is connecting the first and the second belt wheels. The coupling further comprises an actuator 55 which is connected in rotational force transmission manner to the mass element 42. There is a control arrangement 100 arranged in connection with the actuator, which is arranged to control operation of the actuator. Instead of being on the opposite side to the mass element the actuator may be between the belt wheel and the mass element.

[0039] The control arrangement 100 is arranged to adjust the moment of the actuator 55 so that with mass element is applied an effect diminishing the machine directional concurrent vibration of parallel rolls to the web rolls of the set. Thus the arrangement provides a combined effect of a tuned torsional vibration absorber 42 and quick acting actuator 55 via the rider roll to the the machine directional concurrent vibration of the web roll 25.

[0040] Fig. 6 shows an arrangement 102in connection with mass element 42for detecting and monitoring the torsional vibration of the mass element 42. This monitored data is sent to the control arrangement 100. If the web rolls 25 start machine directional vibration, that is transmitted to the rider roll and also the mass element 42 starts rotational vibration. The control arrangement is arranged to detect the rotational vibration of the mass and to determine a control signal to the actuator 55 such that the operation of the actuator 55 based on the control signal enhances to effect of the mass element 42.

[0041] In figure 7 there is shown in an exemplary manner a use of centrifugal pendulum absorber 57 in connection with the rider roll and or the mass element.The centrifugal pendulum absorber is basically a pendulum attached to the rotatable mass element to absorb various torsional vibration modes of the rider roll caused by the machine directional vibration of the roll in the set. The pendulum or pendulums attached to the rider roll or to the tuned torsional vibration absorber are configured so that their natural frequency is equal to a resonant frequency of a vibration mode of the web rolls. Thus, whenever the set undergoes a vibratory excitation of that frequency and would otherwise begin to resonate, the attached, or coupled, pendulums begin to also resonate at the same frequency and will absorb, or at least damp, the machine directional resonant vibrations of the web roll. In the shown embodiment the pendulums 59 are arranged inside the mass element 42.

[0042] In the figure 8 there is shown example of the effect of the invention. In the figure the graph 70 depicts the case without the tuned torsional vibration absorber, the graph 72 depicts the case where the rider roll of the winder is provided with a tuned torsional vibration absorber being tuned at 11.5 Hz and having a mass moment of inertia 0.5 kgm/s2 and damping ratio 7.8 %, the graph 74 depicts the case where the rider roll of the winder is provided with a tuned torsional vibration absorber being tuned at 11.5 Hz and having a mass moment of inertia 7.5 kg/m2 and damping ratio 7.8 % and the graph 76 depicts the case where the rider roll of the winder is provided with a tuned torsional vibration absorber being tuned at 11.5 Hz and having a mass moment of inertia 7.5 kg/m2 and damping ratio 15.6 %. The characteristics of the winder were: width of the set 7 m, diameter of the web rolls 900 mm, the mass eccentricity of the web rolls 0.01 mm, diameter of the winding drums 800 mm, diameter of the rider rolls 200 mm. From the figure it can be seen that the height of the resonance spike is reduced by more than 50 % when the whole frequency range is considered and more than a decade at the tuning frequency 11.5 Hz. Increasing the mass moment of inertia of the absorber moves the absorber induced resonance spikes further apart from the tuning frequency and increase of the absorber damping reduces the spike height.

[0043] It should be noted that only a few of the most preferable embodiments are disclosed above. Thus, it is obvious that the invention is not limited to the above-mentioned embodiments but it can be applied in many ways within the scope defined by the appended claims. The features disclosed in connection with various embodiments can also be used in connection with other embodiments within the inventive scope and/or different embodiments can be combined from the disclosed features, should it be desired and should it be technically feasible.

Claims

1. A two-drum winder for winding partial webs (10) for a fibrous web comprising at least two surface support elements (15, 20) to support a web roll (25) from below and a rider roll (30) which is arranged to support said web roll (25) at least for part of the forming time of the web roll above it, characterized in that the rider roll (30) is provided with a tuned torsional vibration absorber (40) arranged to attenuate rotational vibration of the rider roll such that the machine directional concurrent vibration of the web roll is attenuated via tangential force interaction between the rider roll (30) and the web roll (25).

2. A two-drum winder for winding partial webs (10) according to claim 1, characterized in that the tuned torsional vibration absorber comprises mass element (42) which is coupled by a coupling device to the rider roll (30) to rotate along with the rider roll.

3. A two-drum winder for winding partial webs (10) according to claim 2, characterized in that coupling device comprises a section which is flexible to a predetermined extent.

4. A two-drum winder for winding partial webs (10) according to claim 2 or 3, characterized in that coupling device comprises a torsion bar.

5. A two-drum winder for winding partial webs (10) according to claim 1, characterized in that the rider roll (30) is supported by a beam (35) extending over the length of the rider roll (30) and comprising end walls (35') at the opposite end thereof and the that the tuned torsional vibration absorber is rotatably supported to the end walls.

6. A two-drum winder for winding partial webs (10) according to claim 1 or 4, characterized in that the tuned torsional vibration absorber is rotatably supported inside the beam (35).

7. A two-drum winder for winding partial webs (10) according to claim 2, characterized in that coupling device comprises belt drive coupling having a first belt wheel connected to the rider roll and a second belt wheel connected to the mass element and a belt connecting the first and the second belt wheels.

8. A two-drum winder for winding partial webs (10) according to claim 7, characterized in that belt is a flexible belt.

9. A two-drum winder for winding partial webs (10) according to claim 1, characterized in that the tuned torsional vibration absorber is arranged adjustable during operation of the two-drum winder (10).

10. A two-drum winder for winding partial webs (10) according to claim 7 or 9, characterized in that coupling device comprises belt drive having a variably controllable transmission.

11. A two-drum winder for winding partial webs (10) according to claim 2 or 9, characterized in that the tuned torsional vibration absorber (40) is power transmission connection with an actuator and that the winder comprises a control arrangement (100) arranged to control the operation of the motor actuator in response to acquired torsional vibration of the mass element such that the motor actuator synchronized with the mass element increasing the effect of the mass element.

12. A two-drum winder for winding partial webs (10) according to claim 1, characterized in that tuned torsional vibration absorber comprises a centrifugal pendulum absorber coupled by a coupling device to the rider roll (30) to rotate along with the rider roll.

Drawing