FI118259B - Method and apparatus for guiding the web - Google Patents

Description

118259

Method and apparatus for guiding the web

The invention relates to a method of guiding a web of the type shown in the preamble of claim 1. The invention also relates to a device of the type described in the preamble of claim 8.

At the end of the paper machine or paper finishing apparatus, a paper web manufactured and / or processed in the previous machine parts, usually several meters wide, is rolled into a machine reel around a reel roll. In this winding, a rotating roller cylinder is usually used to guide the paper web to the machine roll, whereby the nip contact between the winding cylinder and the machine roll affects the quality of the resulting roll. A conventional solution is one in which the winding cylinder is pressed and the reel roll around which the reel grows in a nip contact is moved as the reeling progresses in the support structure, for example by supporting the ends of the reel roll with the reeling rails. The ends of the spool reel are actuated by a suitable loading mechanism to adjust the nip contact between the resulting machine roll and the winding cylinder. Such roll-20 concepts and the associated loading methods are disclosed, e.g. in Finnish Patent 91383, corresponding to US Patent 5,251,835; and in Finnish Patent Application 950274 and the corresponding US Patent 5,690,298.

In addition, there is known a solution in which the winding cylinder is arranged in your movable carriage and the machine reel is rotated by the center drive in a fixed winding position, i.e. the center of the reel roll remains the same. As the radius of the machine roll * · · increases, the winding cylinder moves so that the carriage supporting it moves in the guide. Such an arrangement is known e.g. Europe -: * · *: 30,279,2829, corresponding to US Patent 5,988,557.

··· * · * · · * · *; U.S. Patent No. 5,370,327 discloses a solution in which the winding cylinder is movable vertically, thus allowing the angle of the nip between the winding cylinder and the machine: V: 35 to be kept constant as the roll moves on the ·: ··: winding rails. The low position and vertical movement of the reel roller allows the reel rolls to be moved from storage to the reel position along two straight transfer paths. The solution consists of two pairs of reeling carts, from which a couple of full machine reels can return past another pair of reel-guided reels to retrieve a new empty reel reel.

In addition to the stationary winding cylinder which guides the web to the roll, according to Finnish patent application 950274 and the corresponding US patent 5,690,298, a lower, vertically displaceable auxiliary roll which forms a second nip with the machine winding station can be used. Prior to replacement, these 10 auxiliary rollers are in contact with a fully loaded roll which has been released from the reeling cylinder. A similar arrangement in connection with an exchange event is disclosed in Fl patent 91383 / US patent 5,251,835.

Also known from EP-860391 is a roller, in which the web is guided to 15 rolls through a belt or wire passed through guide rolls. This allows a belt or wire to provide a long winding nip in the lower half of the roll with uniform pressure. The pressure can be adjusted via belt or wire tension. The belt or wire loop can be tilted vertically so that, in the direction of web travel, the first guide roll 20 can be lifted against a new reel roll resting on the winding rails above the belt. As the roller grows forward, it rolls forward on the roller rails so that it is in continuous contact with the downward slope of the wire or belt following the guide roller, through which the · · web is rolled.

• · · • · ·; \ 25

Further, U.S. Patent No. 5,531,396 discloses a reel in which a wire loop is passed over a winding cylinder so that it guides the web to a reel formed after the winding cylinder.

{* ·]: 30 A problem with wire or belt rewinders is the introduction of the web into the wire or belt loop. The web is introduced as in EP-* * * mentioned above.

/. 860391 is shown, for the loop at the point where the wire or belt curves ** * | on the first guide roll. The center angle of the arc that the web passes under the direction of the guide roll before moving to the straight line of the loop, Yi 35, may be called the coverage angle. The coverage angle ·: ··· is therefore the angle of the sector covered by the web as it passes through the curved portion of the wire or belt. From EP-860391 it is apparent that the web 118259 3 enters the loop guided by a preceding guide roll with a coverage angle of more than 90 °. The problem with wire or belt loop rewinders is the difference in velocity of the outer surface of the loop due to the loop bending at the guide roll. In a certain thickness of the belt-like material 5, so-called. a neutral axis that always runs at the same speed, regardless of the curvature of the belt's path. The outer surface of the radially outer surface of the neutral shaft from the neutral axis travels faster than the neutral axis by the curved portion at the leading roll, while the subsequent straight 10 portion has the same velocities of the outer surface and the neutral axis. At high coverage angles, the web tension increases at the guide roll due to the higher surface speed, which can result in loosening of the straight portion following the guide roll and even bag formation. This leads to problems with the adjustment of the roll, since the increase in tension must be taken into account in the adjustment of the tension.

It is an object of the invention to provide a novel belt or wire method for guiding the web in a reel, which method does not have the problems of instantaneous tension, and the reel parameters can be selected according to the desired roll quality. To accomplish this purpose, the method of the invention is essentially characterized by what is set forth in the appended claim 1. ··. * ·. the character section. The coverage angle at the first guide roll inside the loop and at the same time the web tension is controlled by a movable track guide roll, the position of which defines the web inlet angle to the loop and J / respectively on the wire or V belt around the guide roll.

• · «• · ···

The track guide roll is located immediately before the loop so that the track 30 runs directly from its circumference to the loop. The track guide roll is preferably: ***: on the same side of the track as the outer surface carrying the loop web, where ♦ ·· /. at the same time, air can be prevented from entering between the outer surface of the loop and the web * · *.

····· ♦ · «: Y: 35 For other embodiments of the invention and their advantages, reference is made to the following dependent claims and the description which follows.

118259 4

The invention will now be described in more detail with reference to the accompanying drawings, in which Fig. 1 illustrates the basic principle of the method of winding in a winding side view, Fig. 2 illustrates the behavior of a web when it enters the loop;

Figure 1 illustrates a continuous roller winder in which a normal, multi-meter wide web web W from a preceding portion of a papermaking or paper finishing apparatus passes through a winding nip N to a roll R. The Tu-Kiel 1 is passed through two guide rollers 2 and 3, at each of which the direction of the running of the member 1 is reversed. In the running direction of the web 20, the first guide roll 2 may form an initial "hard nip" roll with the start roll so that the support member 1 is in contact with the roll at the point where it passes the support roll 2. Mana on its surface. The latter guide roller 3 or the first guide roller • · 2 may be a drive roll, i.e. a drive roller, or both rollers may be provided with a '*' *. * 25 for their own use. Preferably, only the latter roll is a draw roll, whereby the portion of the loop guiding the loop of the support member 1 and forming the nip V with the roll is tighter.

• · * • · • • •

The web passes, guided by the support member 1, onto a machine roll R which is formed by its own center drive around a rotatable reel roll 5. The spool reel 5 has the possibility of moving in the machine direction in the direction of the machine. with respect to the loop of the tongue member 1, and this is arranged such that the bearing housings at the ends of the reel roller, which allow the reel roller 2 to rotate, are supported by suitable support structures. The roller connection: Y: 35 also has a depot (not shown) of empty reel rolls 5, from which *: ··· the rolls are brought to a replacement position at the first guide roll 2 to replace the web entering the full machine roll R. The roller 118259: 5 is changed at production speed, i.e., a high speed full web roll of paper is changed to run on a new reel imported reel, which is rotated at a peripheral speed corresponding to this speed by its own center drive.

5

The machine roll R can be moved in the machine direction by a transfer device 7 which supports the bearing housings at the ends of the reel roll and is moved by means of actuators attached to the reel body. The transfer device 7 is arranged to move on machine-oriented, substantially horizontal roller rails 10, and consists of a carriage at each end of the reel roll which carries the bearing housing of the reel 5 end.

As the diameter of the machine roll R increases and the roll moves forward, it is in continuous contact with the support member 1 due to the fact that the transfer track 7 of the transfer device 7 and the web carrying portion of the support member 1 form an angle opening 15. In Fig. 1, the upper web-carrying portion of the loop of the support member 1 is obliquely downwardly in its direction of travel with the transverse path of the roll R (and the reel roll 5) being substantially horizontal.

The transfer device 7 is moved along the winding rails 6 in the forward direction of the web as the diameter of the roll R increases, so that the roll is always in contact with the loop of the support member 1 so that the web moves to the periphery of the web. in the reeling nip N between said outer periphery, the reeling nip N thus moves forward continuously in the direction of travel of the upper portion of the loop, as the reel increases. When the roll R is full, the reel roll 5 forming the new roll core • * 4 is brought into the exchange position and the web is changed to run around it at production speed. The entire roll R is removed from the transfer device 7, and the transfer device is moved back to the beginning of the web-carrying portion of the loop 30, and a new reel roll 5 around which a new web has begun to accumulate after replacement is released from the start winding station.

• * · • · · * *****

Figure 2 shows the factors affecting the behavior of the web in the loop: V: 35 of the support member 1. Before the loop of the support member is a track guide roll 8, ·: ··: whose position defines the web W inlet loop, i.e. the web runs straight from the circumference of the roll 8 to the curved portion of the loop formed by the track guide roll 2. The straight section of the web thus, viewed from the side, joins the common tangent to the circumference and the arc of the track guide roll 2.

Figure 2 shows the track tension in the machine direction (MD) at various points and the factors affecting it. In the figure, the entry of the web W into the loop is guided by a track guide roll 8 whose circumference extends directly to that portion of the loop of the support member 1 which curves over the circumferential surface of the first guide roll 2. In the following discussion, the support member 1 will be referred to as a belt 10. The phenomena shown below occur in all planar flexible support members having a certain thickness introduced around the guide roll 2.

In Figure 2, the markings mean the following: 15 v0 = belt neutral axis speed (and belt surface velocity on straight leg) [m / s],

Vt = surface velocity of belt with curved part (at roll) [m / s]

Rr = radius of belt guide roll [m], 20 sb = thickness of belt [m], sn = distance of neutral axis of belt from inner surface of belt [m], a = angle of coverage (rad), T0 = straight line tension [N / m], «·. .. Ti = max. web tension on the curved portion of the belt [N / m], and '**. * 25 = track length from the previous holding point on the belt [m], • · • · *: Suppose that ideally the web speed W on the straight section of the belt is equal to speed of neutral axis (and belt speed on straight section) v0.

30 • ·

Holding point means the previous point of track entry where the track and. there is grip between the track-driving member. Typically, such holding points are drying and traction groups and grooved rollers. In this case, the track guide roll 8 forms such a holding point.

35 • · ·: · *: It is clear from the figure that the surface speed of the belt at roll 2 is:

J

7 118259

Rr + Sb ...

v '= tTtXv »(1)

The increase in web tension can be described by the following equation: 5 ΔΤ = Ή -T0 = ε · Ε · (1- β'ντ), (2) where 10 ε = relative elongation, E = web elastic modulus [N / m], t = action time (time taken by the track against the curved part of the belt) [s], and τ = time constant (time taken from the previous holding point to the belt) 15 [s].

The relative elongation ε due to velocity differences is simply obtained by dividing the velocity increase v ^ vq by the original velocity v0.

The time constant τ is thus calculated from the previous image by the formula IVvq.

• * ·

From the previous formula (2) it can be stated that the longer the web is against the curved part of the belt, the more the tension increases. Calculations * · * · * can normally show that the constant t / τ is obtained as follows: 14 ···.! 25 * *, * t! ~ - ^ V0 — a (^ r Sb) V0 \ L, ··· It is seen that by adjusting the track angle a first! ···. at the same time, the rise of the track tension on the guide roller 2 can be adjusted by the curved portion of ΔΤ • · 30 belts. Similarly, keeping the web coverage angle α over the first guide roll 2 remains constant, the paper *: '* · tension increase ΔΤ on the curved portion of the belt remains constant. From formula (3). ·! ·. also shows the same thing, which is already clear from Fig. 2, that .1.1: when the web coverage angle a is zero, so is the increase in paper tension Δ on 35.

118259 8

In addition, it can be computationally shown that the tension can never increase with the curved portion of the belt more than the grip between the belt and the web. If the tension increase due to geometry were 5 greater than the grip, the paper would begin to slip on the belt and the tension increase ΔΤ would be the amount of grip. Namely, it can be calculated that the mean normal force / width meter applied to the curved part of the web belt is 10 FN = (α / 2tt) (T0 + T- |) / 2 where Fn = normal force [N / m]

The grip between the web and the belt is obtained as follows.

15 FM = pFN = μ (α / 2π) (Tq + TO / 2 where μ = friction coefficient

Other entries are the same as above.

20 When driving at constant track tension, adjusting the track angle a over the first guide roller 2 allows the track tension increase ΔΤ to be adjusted by the curved portion of the belt, since the tension increase ΔΤ cannot exceed the grip FM.

In Figures 1 and 2, the arrow M illustrates the possibility of moving the track guide roll 8 relative to the loop of the support member 1 such that the track entry point ·· ·: changes over the support member and the coverage angle α, respectively. The guide roll 8 is thus moved relative to the first lead roll 2 inside the loop. For this purpose, the track guide roller 8 may be arranged on the roller body "*; 30, for example, to be substantially vertically movable along a · / ** linear line.

• Figure 3 shows another alternative. It illustrates the possibility of changing the position of the loop of the support member 1 vertically so that the first guide roll 2 can be located at different elevation positions. The turning point may be a second guide roll 3, for example according to the solution known from EP-860391. Here, the guide 8 defining the angle of coverage α is mechanically coupled to the loop of the support member so that it moves as the loop is moved, but its position remains constant relative to the running of the loop of the support member, i.e. the line between the axes of the track guide roller 8 and the first guide roller 2 of the loop is always at the same angle 5 directly with the axis of the first guide roller 2 and the second guide roller 3. Figure 3 illustrates the coverage angle at the angle between the extension of the straight portion of the loop of the support member 1 and the straight portion of the pre-loop web, which according to the laws of geometry corresponds to the coverage angle α.

10

In the alternative of Figure 3, it is still possible to arrange the track guide roll 8 to be adjustable in position relative to the loop of the support member 1, although it is kinetically coupled to the loop of the support member so that it moves with the movement of the loop. Hereby, the track guide roll 8 can be arranged 15, even vertically, to pivot into the loop body, which can be moved by moving the entire loop. Actuators can be provided between the swivel arms supporting the track roller and the loop body to accomplish this swinging motion.

When the coverage angle α is adjustable or maintained constant, the increase in tension at the guide roll 2 is known and may be taken into account when selecting the creep parameters. Preferably, the aim is to keep the coverage angle below 90 °, more preferably below 45 °. When adjusting the coverage angle, it is attempted to adjust it to *** · [25 so that its value remains below the amax of the above maximum values] *. Advantageously, the coverage angle is always greater than 0, even if it is sought to set it as low as possible, so that there is no problem of fluttering of the web, but the movement of the web from its free portion to the support member 1 (belt) is controlled. Tension I '·'; In order to minimize the 30 inclines, it may be advantageous to keep the coverage angle below 20 ° s * '*: and / or to change its magnitude to this maximum value amax ♦ · ♦ /. below. The adjustable or constant ** * j angle of coverage is particularly useful in methods where the reel roll \ * 5 is center-driven and the tension of the web layers of the resulting roll R: Y: 35 is affected by adjusting the line tension by the immediately preceding · center drive torque (winding force).

118259 10

Of particular importance is the adjustment of the coverage angle when the winding nip N 'is on the curved portion of the support member 1, i.e. the roll is at the guide roll 2 to form a so-called. '' Hard 'nip. This situation, which may occur during the initial winding, is illustrated by the dashed line in Figure 2. In this, the web passes through a curved portion less than the normal coverage angle α in Figure 2 before the nip N '. By adjusting the size of the coverage angle α 'preceding the nip N' corresponding to the said sector, the tension W of the web 10 going to the roll 10 can be influenced. For example, by changing the position of the track guide roll 8 with respect to the guide roll 2, the coverage angle a 'may be desired for initial winding, or generally for a situation where the nip N' between the roll and support bar is at a position As the winding progresses, the winding nip moves to a straight portion of the 15 loops, where the winding proceeds as described above in connection with FIG.

Yet another possible parameter is the tension of the support member 1 itself. However, this has no effect on the track tension, but can influence the radial force between the peripheral surface of the roll and the outer surface of the loop in the winding nip, i.e. the nip load. Preferably, the method of the invention also uses this as one adjustable parameter. The tension of the support member can be adjusted, for example, by means of a tensioning roll in contact with the loop.

The invention is not limited to the foregoing embodiments but may be modified within the scope of the inventive idea of the claims.

: * · *: 30 The planar flexible support member 1, which forms a loop closed by two or more rollers, is preferably air permeable, for example a wire. However, within the scope of the invention, support members which are · · · · · Ί impermeable to air, e.g.

The support member has the same structure across the machine, i.e. it corresponds to: Y: 35 width of the web to be rolled. However, the invention also encompasses the idea that the loop consists of a plurality of parallel loops, with the general geometry being sideways and exactly the same as in Figures 1-3, with adjacent loops covering the track width and passing through common guide rolls 2. and 3 around. Here, for example, the tension of the loops can be independently adjusted according to the principles known in EP-860391. Here, however, the tensioning behavior of the web 5 at the guide roll 2 is also influenced by the same factors as shown in Figure 2.

The loop movements of Fig. 3 may be of other types, e.g. both guide rolls 2 and 3 may be movable simultaneously. Likewise, it is conceivable that the track guide roll 8 can be displaced in the web running direction so that the length U of the straight track portion between it and the first guide roll 2 can be displaced.

···., • · · Λ »φ • * *» · · · * * · *%%%%%%%%%%%%%%% · · · · · · · · · · · · · ··········································· · · · · · • · ♦ * * »···· * *

Claims (14)

118259 12 A method for winding continuously rolling a paper web 5 into rolls around a rotating winding core, such that: - the web (W) is guided into a roll (R) around a winding core (5) through an endless loop of support member (1) and a roller (R); - at least at some point moving the winding core (5) relative to the loop of the support member (1) according to the increase in diameter of the roller (R) so that the position of said winding nip (N) moves forward along the web-carrying portion of the endless support member (1) that the coverage angle (a) of the web (W) at the first guide roll (2) of the loop of the endless support member (1) and at the same time the web tension at the first guide roll (2) is controlled by moving the web guide roll (8) Method according to Claim 1, characterized in that the track guide roll (8) is moved relative to the loop of the support member (1) so that the coverage angle (a) is changed. • • · i «« I i * · * Method according to Claim 1, characterized in that the track guide rolls (8) are moved along the loop of the support member (1) so that the coverage angle (a) remains substantially constant. • · · • · • «• · 4 Method according to one of the preceding claims, characterized in that the air passage between the web (W) and the loop: * · [: 30] of the support member (1) is prevented by placing the track guide roll (8) on the same side of the track; · * ♦ • · • * · ** '. A method according to any one of the preceding claims, characterized in that the coverage angle (a) is adjusted to less than 90 ° (amax). : V: 35 The method according to claim 5, characterized in that the coverage angle (a) is adjusted to less than 45 ° (amax). 118259 13 Method according to claim 6, characterized in that the coverage angle (a) is adjusted to less than 20 ° (amax). A device for guiding a web in a reel arranged to continuously roll a paper web into rolls around a rotating reel core, comprising: - a transfer device (7) for moving the reel core (5) and the reel (R) formed around it during which the paper web (W) (R) through a winding nip (N), - a loop formed by an endless support member (1) having a web-carrying portion forming a winding nip (N), wherein the transfer device (7) is arranged to move the winding rolls 15 so that said winding nip (N) moving in the direction of travel of the web-carrying portion, - a first guide roll (2) within the loop located at the beginning of the web-carrying portion forming a winding nip (N) in the travel direction of the support member (1) ) that is organized on the move an opening for controlling the web coverage angle (a) at the guide roll (2). • · t * · • «· · Device according to Claim 8, characterized in that the track guide roll (8) is arranged to be displaced relative to the loop so that the coverage angle (a) of t1: V is changed. ··· '• · • · • · · Device according to Claim 8, characterized in that the track-30 (8) of the track-30 is coupled to the loop for transfer with it. • · • · · • ♦ * · / *. Device according to one of Claims 8 to 10, characterized in that the track guide roll (8) is disposed on the same side of the track as the loop of the supporting member (1). : Y: 35 Device according to one of the preceding claims 8 to 11, characterized in that the track guide roll (8) is movable with respect to the loop 118259 14 or is positioned relative to the first guide roll (2) such that the coverage angle (a) is less than 90 ° (amax). . Device according to Claim 12, characterized in that the 5 track guide rolls (8) are movable with respect to the loop or are disposed with respect to the first guide roller (2) such that the coverage angle (a) is less than 45 ° (amax). Device according to Claim 13, characterized in that the track guide roll (8) is movable with respect to the loop or disposed with respect to the first guide roll (2) such that the coverage angle (?) Is less than 20 ° (amax). * '' '1. • k · * • 4 * 4 »l · k 4 k • · * * • k *« · * · * * k · * ··· * * ·· * • k * k • · • · · · · • «4 4 4. • k» • · · * 4 k 4 4 4 4 k 4 k «k 4 4 • • 4 444. kk 4 4 4 4 4 4 k 4 # k 4 4 4. 4 4 4 * • 4. '. 4 4. 4 44444 * 4 15 118259