FI130421B - Cutter for a pulp web - Google Patents

Abstract

The invention relates to a cutter for a pulp web. The cutter (10) includes consecutively a slitter (11), a cross cutter (12) and a layboy conveyor (13) for overlapping cut sheets (14) before a bale table (15). The layboy conveyor (13) includes several individual groups (23) of support rolls (24) set opposite to press wheels (25). At least one of the groups (23) is tiltable downwards for cleaning up the cutter (10).

Description

CUTTER FOR A PULP WEB

The present invention relates to a cutter for a pulp web, which cutter includes consecutively a slitter, a cross cutter and a layboy conveyor for overlapping cut sheets before a bale table, and which layboy conveyor includes several indi- vidual groups of support rolls set opposite to press wheels.

In a pulp machine, after a pulp dryer, there is a cutter for a pulp web. In the cutter the pulp web is first slitted lon- gitudinally and then crosscut into sheets. After the cross- cutting, there is a layboy conveyor having several support rolls for moving and overlapping sheets to a baling table. In the prior art, there are seguential groups of support rolls with speed differences and thereby the speed of the sheets is slowed down with the layboy conveyor. In this way, the cutter reduces the sheet speed lower than pulp web speed and arrang- es the sheets partially over each other ready for stacking.

For example, if the pulp dryer runs 200 meters per minute, the sheets enter the baling table at speed of 100 meters per minute. EP2531430B discloses one known cutter as well

FI111446 does. e Even at the end of the production something may go wrong.

S 25 Usually, the problems accumulate at the layboy conveyor. The © support rolls together with the press wheels form tight nips © which convey and overlap the sheets. If any sheet jams, there = will be many sheets jammed in seconds usually causing stop-

N ping the whole cutter. Even if stopping is guick, plenty of = 30 sheet may stuck to the layboy conveyor. Although some of the

N press wheels are liftable, it is hard to clear and reach the

N sheets from a distance and clean the cutter. The cleaning takes time and needs a lot of labor. Also the press wheels or other structures may be damaged.

The object of the invention is to provide a new kind of cut- ter for a pulp web which is easier and faster to clean than before. The characteristic features of the cutter according to the invention are stated in the accompanying Claims. The cutter can be easily cleaned and returned back to the produc- tion. The cleaning is quick and safe, and it can be even au- tomated. This shortens the down time and thereby increases the yield of the pulp. The cleaning ties up labor much less than before. The new and surprising functionality can be im- plemented easily also in the cutters now in action.

The invention is described below in detail by referring to the enclosed drawings, which illustrate one embodiment of the invention, in which

Figure 1 shows a side view of a cutter according to the in- vention during production,

Figure 2 shows the cutter of Figure 1 after a jam.

In a cutter, a uniform and full wide pulp web is first cut lengthwise and then in cross direction into sheets, which then are stacked as bales. Figure 1 shows the cutter in ac- tion. The cutter is for a pulp web produced with a pulp ma-

N chine (not shown). The cutter 10 includes consecutively a

O 25 slitter 11, a cross cutter 12 and a layboy conveyor 13 for

N overlapping cut sheets 14 before a bale table 15. The slitter 0 11 includes several parallel blades 16 arranged against a = bottom slitter 17. When the pulp web 18 runs through the

N slitter 11, several longitudinal strips are formed. From = 30 there the strips are pulled by a feed press 19 and further

N pushed to the cross cutter 12. In other words, the slitter 11

N cuts the pulp web 18 lengthwise into parallel strips, which are then crosscut into sheets 14 with a rotating cutter roll 20 with cross cutting knifes 21 having a stationary counter blade 22. These sheets are then overlapped with the layboy conveyor 13 to the bale table 15 as bales. The bale table de- scends little by little until the bales are completed.

In the cutter the speed of the sheets is slowed down between the cutter roll 20 and the bale table 15. During the layboy conveyor the movement of the sheets 1s decelerating, the slowing down thus enabling the stacking to be done at a suf- ficiently low speed and therefore without problems while the machine speed remains higher. For this, the layboy conveyor 13 includes several individual groups 23 of support rolls 24 set opposite to press wheels 25. For each feed roll there one set of press wheels. In this way, nips are formed between the support rolls and the press wheels. When the support rolls are driven, the sheets move forward. As shown in Figure 1, already at the first group 23, the sheets 14 are partly over- lapping. With the next groups the sheets are overlapped fur- ther and finally at the bale table 15 the sheets are top of each other forming bales. After the bale table, the bales are wrapped and usually also tied up, and transported forward.

According to the invention, at least one of the groups 23 is tiltable downwards for cleaning up the cutter 10. The tilting

N of one or more groups opens the layboy conveyor making it

S 25 easy to clean up the cutter. In practice, the opening is

N guick to do, so any additional damages can be avoided. Also, 0 there is plenty of room for pulp sheets. Thus the crosscut- = ting may continue if the problem was in the layboy conveyor.

N In this way, the production may start again right after the = 30 layboy conveyor is cleaned up. If the problem was in the

N slitter or cross cutter, the pulp web is run down before the

N cutter. Then starting the production requires tail threading and other start-up steps.

Generally, the cutter 10 includes three or more groups 23 of at least two first are tiltable downwards. In Figure 2, there are three groups 23 and two of them are tiltable. Preferably, the two first groups are supported in a common frame, which is pivoted to the frame of the cutter. This kind of structure is simple, and the common frame may tilt even by gravity when the common frame is released to start the cleaning. Then the tilting is quick and safe, without any further damages. Suit- able cushions or shock absorbers may be used. Also, the lay- boy conveyor is totally open downwards when tilted. So, the pulp sheets will fall downwards by gravity. After cleaning up the layboy conveyor, the common frame is lifted up with a suitable actuator, for example and the common frame is locked into the upper position. In principle, all groups may be tiltable. Advantageously, the tilting groups are arranged as a slope backwards. In this way, the jammed sheets are easily moved to a pulper 26 positioned before the cutter 10.

As shown in Figure 2, at least the tilting groups 23 are re- versible. Here, all groups are reversible. In practice, these groups are run backwards and/or jogged thereby moving the jammed sheet towards the pulper 26. In principle, one or more of the groups 23 are reversible and/or able to be jogged. In

AN this way, the cutter can be cleaned up without any manual

O 25 work at its best. The aid the cleaning, there is a broke

N slide 27 as an extension to the tilting groups 23. The re- 0 versed sheets will slide into the pulper 26 almost by them- = selves. During test runs, even 90% of the pulp sheets were

N removed by the new structure without touching by hand or any = 30 handheld accessory or tool. If necessary, the groups may be

N run back and forth, i.e. jogged for aiding the removal. In

N practice, each support roll or group may have own push button for jogging. Thus each roll or group may be jogged inde-

pendently in a desired order for clean up the position having problems.

When the jam is noticed, the pulp web is run down as soon as 5 possible. As mentioned earlier, if the slitter and the cross cutter work properly, the cut pulp web is run down after the cross cutter. For this, there is a broke lid 28 for broke be- fore the first group 23. After the jam, the broke lid is opened, and the sheets are dropped down towards the pulper.

Thus no sheets will enter to the layboy conveyor which can be then guickly cleaned up by opening and reversing according to the invention, as described earlier. If needed, any remaining sheets are removed manually safely on the service bridge 29.

For example, the sheets may be pushed backwards towards the pulper from the service bridge 29 with aid of a long pole.

Jammed sheets can be moved also with blows from assembled pipes or from handheld hoses. Here is also a reject gate 33 positioned under the layboy conveyor 13. At the jam, the sheets will drop down to the reject gate 33 and there by to the broke slide 27. The reject gate 33 will be inclined to the same angle than the lowered group so that there is con- tinuous support for the sheets when the layboy conveyor 13 tilts down (Figure 2). The reject gate can be opened without

N tilting the layboy conveyor if there are problems in baling.

S 25 Also the cross cutting may continue and the production start

S again when the problems are settled.

O

= When the groups are tilting, the majority of the press wheels

N 25 can be fixed. This will simplify the structure of the = 30 whole layboy conveyor. However, the press wheels 25 in a non-

N tiltable group are preferable liftable. This helps cleaning

N the cutter. The liftable press wheels 25 are shown in Figure 2 with arrows pointing up. The press wheels are lifted a lot, about 500 mm thus enabling easy removing the sheets. Also,

the last press wheels may be reached from the service bridge.

This improves occupational safety a lot. Finally, the cutter can be cleaned automatically and very quickly. If something is broken, it can be easily fixed before starting the produc- tion again.

The tilting groups open significantly which improves the cleaning. In practice, the tilting group 23 opens up to 400 - 2000, preferably 700 - 1400 mm. This is measured from the first group which tilts the most. At the same time, the slope has significant inclination which aids the removing of the sheets. In principle, the tilted groups 23 from a slope hav- ing an angle of 10 - 45 degrees, preferably 15 - 30 degrees.

Also, the common frame itself may tiltable. In other words, the tip of the common frame may tilt more than the rest of the common frame, or vice versa. In this way, the groups need smaller space to tilt, or several groups can be arranged to tilt.

In practice, there are two or three support rolls 24 in each groups 23 and one drive 30 for rotating the support rolls 24.

In this way, each sheet is moved properly. Also, the groups can be controlled independently to slow down the speed of the

N sheet. Finally, the sheets will overlap into a proper bale.

S 25

N Indeed there is personnel supervising the production in situ 0 or remotely. If any jam is detected, the cutter is stopped if = necessary and cleaned up. According to the invention, the

N layboy conveyor 13 includes one or more sensors 31 set from = 30 one side towards the sheets 14 to notice any jamming. In this

N way, any jamming or blockage can be detected immediately

N thereby shortening the break time. The sensors may be ultra- sonic or infrared, for example. First the sensors detect if there are excess sheets causing the jamming. The advanced sensors can also detect in which crosswise position the jam is. This will aid the cleaning while the personnel know the location of the jam. Usually, there are about ten parallel sheets.

Advantageously, any Jamming is arranged as a tricker for starting a cleaning-up sequence to clean up the layboy con- veyor. In other words, if any jamming is detected, the layboy conveyor will open and the jamming sheet are returned into the pulper. Simultaneously, the broke lid is opened. These operations may be as a sequence. Thus cleaning can be easily automated. If the problem was only due to the layboy convey- or, the production may continue shortly after cleaning since the cross cutter may run during the cleaning up the layboy conveyor. During the cleaning of the layboy conveyor, the pulp web can be run down through the broke lid. When the lay- boy conveyor is ready again, the production may continue im- mediately. This shortens the break time significantly.

To improve the cleaning, after the slitter 11 there is a feed press 19 which is reversible. During the break, the feed press may pull back the pulp web. In this way, no more pulp is entering into the cutter helping the cleaning and the

N cross cutter may be also stopped.

S 25

N With the arrangement according to the invention the cleaning 0 up the cutter is newly arranged, the slitter 11 and the cross = cutter 12 can be arranged within safety fences 32. This im-

N proves the occupational safety and reduces litter. At the = 30 same time, also the cross cutter may be reversible. In the

N normal production, the speed of the sheets after the overlap-

N ping step is descending and therefore, the leading edge of each sheet settles on top of the trailing edge of the sheet in front resulting in the sheets to partly overlap each oth- er.

N

N

O

N

N

<Q wn

I a a 0)

O

LO

N

N

O

N

Claims (12)

1. Cutter for a pulp web, which cutter (10) includes consecutively a slitter (11), a cross cutter (12) and a lay- boy conveyor (13) for overlapping cut sheets (14) before a bale table (15), and which layboy conveyor (13) includes sev- eral individual groups (23) of support rolls (24) set oppo- site to press wheels (25), characterized in that at least one of the groups (23) is tiltable downwards for cleaning up the cutter (10), and the cutter (10) includes three or more groups (23) of at least two first are tiltable downwards, and the tiltable groups (23) are supported in a common frame, which is pivoted to a frame of the cutter (10), and the tilt- able groups (23) are arranged as a slope backwards in rela- tion to the running direction of the cutter (10), and one or more of the groups (23) are reversible and/or able to be jogged.

2. Cutter according to claim 1, characterized in that the majority of the press wheels (25) are fixed.

3. Cutter according to claim 1 or 2, characterized in that the press wheels (25) in a non-tiltable group are lifta- © ble. S 25

©

4. Cutter according to any of claims 1 - 3, character- © ized in that there is a broke slide (27) as an extension to E the tiltable groups (23). O N 30

5. Cutter according to any of claims 1 - 4, character- N ized in that there is a broke lid (28) for broke before the N first group (23).

6. Cutter according to any of claims 1 - 5, character- ized the tiltable group (23) opens up to 400 - 2000, prefera- bly 700 — 1400 mm.

7. Cutter according to any of claims 1 - 6, character- ized in that there are two or three support rolls (24) in each groups (23) and one drive (30) for rotating the support rolls (24).

8. Cutter according to any of claim 1 - 7, characterized in that the layboy conveyor (13) includes one or more sensors (31) set from one side towards the sheets (14) to notice any jamming.

9. Cutter according to claim 8, characterized in that any jamming is arranged as a tricker for starting a cleaning- up sequence to clean up the layboy conveyor (13).

10. Cutter according to any of claims 1 - 9, character- ized in that after the slitter (11) there is a feed press (19) which is reversible.

11. Cutter according to any of claims 1 - 10, character- en ized in that the slitter (11) and the cross cutter (12) are N S 25 arranged within safety fences (32). N S x

12. Cutter according to any of claims 1 - 11, character- = ized in that the tiltable groups (23) form a slope having an a e angle of 10 - 45 degrees, preferably 15 - 30 degrees. O LO N N O N