EP1026314A2 - Pressing arrangement - Google Patents

Abstract

The press section of a machine for the production of a paper or cardboard web (10) has two shoe press rollers (22,24) and a central press roller (20) as a common counter roller for them. The roller structure forms two extended roller press gaps (S1,S2) in the direction (L) of web (10) travel. The first roller press gap (S1) has two press blankets through it with the web. The shoe press rollers (22,24) are on opposite sides of the center press roller (20). Two blankets, with the web, can pass through both roller press gaps (S1,S2). The press section uses a max. of three blankets (14,18,28), giving a closed web path through the section, and one blanket (18) moves through both extended roller press gaps (S1,S2). The web (10) is carried through both extended roller press gaps (S1,S2), preferably together with a blanket (18), round a deflection roller preferably as a suction roller (26). The blanket (14) through the first extended press gap (S1) is also a pick-up blanket. On leaving the second extended press roller gap (S2), the web (10) passes over a further preferably suction deflection roller (30) in its path to a following web drying section, together with an upper blanket (28) and the web is separated from the blanket by a smooth roller (32). Or the web (10) is taken from the second press gap (S2) with a lower blanket (18), to be picked from the blanket by a drying blanket (38) at the deflection roller (30). The mantle of the center press roller (20) has blind drillings and/or grooves. The extracted water at both extended roller press gaps (S1,S2) is removed at least partially by spinning off into troughs (34,34a,36.36a). The supports for each press shoe, at both shoe press rollers (22,24), apply equal pressures to them. The length of the first extended roller press gap (S1) is preferably longer than the second press gap (S2). The support for the press shoe at the first shoe press roller (22) can exert a lower pressure on it than at the press shoe at the second shoe press roller (24), where both roller press gaps (S1,S2) have the same length. The mantle of at least one shoe press roller (22,24) has blind drillings and/or grooves. The center press roller (20) has an inner support, with pressures against the two roller press gaps (S1,S2). The web (10) is held against the lower blanket (18) by an additional suction unit (51) between the deflection suction roller (26) and the second roller press gap (S2). The deflection roller (26) has a controlled drive and, with its drive, can be braked to increase the blanket tension in front of the second roller press gap (S2).

Description

The invention relates to a press arrangement for treating a fibrous web, especially paper or cardboard web.

The aim of the invention is a press arrangement of the aforementioned Art to create, their structure as simple and compact and their Vacuum requirements and their drive power is as low as possible. In addition In particular, a closed web guide should also be possible.

This object is achieved according to the invention in that two Shoe press rolls of a central serving as a common counter roll Press roll are assigned to each one in the web running direction to form an extended press nip, and that at least in the direction of web travel considered first elongated press nip is double felted.

Due to this training, the previously usual large, with one thick jacket provided press suction roll, which reduces the vacuum requirement is significantly reduced. Overall, the drive power is significantly lower. In particular, it is also a closed one Web guidance possible, so that the corresponding press section in particular is also suitable for liners with a white top. Because of the use of a common assigned to the two shoe press rolls Counter roll is also the number of press rolls required reduced to a minimum, i.e. there are a maximum of only three press rolls required. The number of required is also reduced accordingly Press felting. With the lower felt consumption, the Reduce operating costs further. These operating costs will also due to the lower vacuum requirement for pipe suction cups and the lower Drive power reduced. It is now also one in particular Arrangement possible, in which the pressing forces largely cancel each other out. In addition, there is less bearing load and less bending stress on roller axis. On an inside supported roller, possibly for all machine widths. The lesser Energy consumption includes due to the fact that in view of the Use of only one common shoe press rolls Counter roller with low bearing friction the friction of the press arrangement is reduced accordingly. With a decrease in the number Felt conditioning is correspondingly less necessary, which is a further reduction in friction and the required Vacuum. There are no power losses by a roller supported by internal support sources. It is only one Gearbox required outside of the paper machine in question, which a brings better efficiency. After the number of used Rolls and roll types is reduced to a minimum accordingly the number of reserve rollers to be kept low, which has a favorable effect on investment costs again. In addition is a simpler control is possible, which means operational safety is increased. Compared to conventional multi-roll presses there is no line force influence by mutual nip forces on. Bombing is generally no longer necessary. To have to also soft roller covers are no longer used, which causes result in correspondingly longer service lives. Train fluctuations on the paper are practically impossible. Accordingly, web tears or breaks within the press section can be avoided. It is especially a simpler, leverless and compact chair with closed power flow possible. With the elimination of press roll scrapers investment costs and operating costs are used for paper acceptance further decreased.

The two shoe press rolls are preferably approximately opposite one another Arranged sides of the central press roll.

In an expedient practical embodiment of the invention Press arrangement, both elongated press nips are double each felted. This results in an overall volume-saving and symmetrical drainage. In papermaking, in particular also improves the equality of the paper, so that the press assembly can also be used in particular for graphic papers.

In a preferred practical embodiment of the invention A maximum of three felts are provided for the press arrangement. A felt can be passed through both elongated press nips. Corresponding only three felt conditionings are required, making the Friction power and the required vacuum can be reduced accordingly. Overall, there is less felt consumption. It is a total compact, inexpensive construction possible. Apart from this, that there is no need for suction press rolls are a closed one Web guidance and relatively short rewetting distances possible. To Every nip is provided with good nip drainage, which among other things for example can be achieved by a respective centrifugal water drain can.

With a closed web guide from the wire to the dryer section high runability is achieved. Web breaks in the press arrangement are practically impossible. There is also no need for manual listing the fibrous web, which means greater operational reliability and machine availability brings with it. Due to the lack of open trains there can be practically no paper stretching and no web tears come. Between the presses there are also no ones that act on the paper Train fluctuations on.

Between the two elongated formed with the central press roll The fiber web can preferably be press nips together with a Felt is guided around a deflection roller, which is preferably designed as a suction roller his.

In an expedient practical embodiment is one by first extended nip led felt simultaneously as a pick-up felt intended.

It is also advantageous if the fibrous web follows the second extended press nip via a preferably designed as a suction roll Deflection roller, for example, led to a subsequent dryer section is. The fibrous web can pass through the second together with one extended press nip running top felt around the guide roller be and then removed from the top felt by a smooth roller become. Alternatively, it is also possible, for example, that the Fibrous web together with a bottom felt from the second elongated Press nip guided and in the area of the deflecting roller through this looping dryer fabric is removed from the bottom felt.

The surface of the central press roll and / or the press jacket at least A shoe press roll can create a certain water storage capacity for example, be blind drilled and / or grooved. In order to the drainage of one or both extended press nips can at least partly by throwing water into a respective channel or the like. This is not just optimal drainage of the respective press nip guaranteed. Lighter press felts can also be used be used. Finally, there is better felt conditioning via pipe suction cups and spray pipes.

In certain cases it may be useful if the press shoes the support devices assigned to the two shoe press rolls same pressures can be applied, in which case the length of the first extended press nip is advantageously greater than the length of the second extended press nip. Here are the same in particular Line forces possible. In an alternative expedient embodiment is the support device assigned to the press shoe of the first shoe press roll can be pressurized with a smaller pressure than that of the press shoe the second shoe press roller associated support device, wherein in this case the two extended press nips expediently one can have the same length. In this case in particular the line force of the second extended press nip in particular be larger than that of the first extended nip.

For weight reasons, it may be appropriate if the central press roll is an internally supported roller and each with the press nips assigned pressures is supplied.

To the felt tension between the two extended press nips influence, it is advantageous if the deflection roller an adjustable Drive.

In the dependent claims, further advantageous embodiments of the Press arrangement according to the invention specified.

Figur 1

eine schematische, teilweise geschnittene Darstellung einer Ausführungsform einer zwei verlängerte Preßspalte aufweisenden Pressenanordnung,

Figur 2

eine schematische, teilweise geschnittene Darstellung einer weiteren Ausführungsform einer zwei verlängerte Preßspalte aufweisenden Pressenanordnung,

Figur 3

ein Beispiel für eine mögliche Steuerung der Pressenanordnung gemäß Figur 1 oder 2 und

Figur 4

ein weiteres Beispiel für eine mögliche Steuerung der Pressenanordnung.

The invention is explained below using exemplary embodiments with reference to the drawing; in this show:

Figure 1

2 shows a schematic, partially sectioned illustration of an embodiment of a press arrangement having two elongated press nips,

Figure 2

2 shows a schematic, partially sectioned illustration of a further embodiment of a press arrangement having two elongated press nips,

Figure 3

an example of a possible control of the press arrangement according to Figure 1 or 2 and

Figure 4

another example of a possible control of the press arrangement.

Figure 1 shows a purely schematic, partially sectioned representation a first embodiment of a press arrangement for treating a Fibrous web 10, which is in particular a paper or Cardboard web can act.

The fibrous web 10 is in the area of a suction roll 12 by a Upper felt 14 taken from a wire belt 16 and then together with a bottom felt 18 extended a first in the web running direction L. Press nip S supplied. Following this, the fibrous web 10 together with the bottom felt 18 a second in the web running direction L fed press nip S2. Before the first extended Press nip S1 is the fibrous web 10 together with the upper felt 14 guided over a deflection roller 19 designed as a suction roller. The however, both rollers 12 and 19 can also be brought together.

As can be seen in FIG. 1, the two are in the direction of web travel L extended press gaps S1 and S2 between a central one Press roll 20 and two associated shoe press rolls 22, 24 are formed. The central press roll 20 serves the two shoe press rolls 22, 24 thus as a common counter roller. Here are the two shoe press rollers 22, 24 on opposite sides of the central Press roll 20 arranged.

As can be seen from FIG. 1, the fibrous web 10 is between the two elongated formed with the central press roll 20 Press nips S1, S2 together with the bottom felt 18 around a suction roll trained deflection roller 26 out. In the area of this deflection roller 26, the upper felt 14 is again separated from the fibrous web 10.

In the present embodiment, both the first and the second elongated press nip S1 or S2 each felted twice. Is to a further upper felt 28 is provided, which together with the lower felt 18 and the fibrous web 10 through the second extended press nip S2 is led. In the present case, the fibrous web 10 is following the second extended press nip S2 together with the upper felt 28 via a deflecting roller 30, again designed as a suction roller, to the first Drying cylinder 32 guided a subsequent dryer section. in the In the area of the deflecting roller 30, the bottom felt 18 is again made of the fibrous web 10 separated. To remove the fibrous web 10 from the The drying cylinder 32 preferably has a closed top felt 28 or smooth surface. As can be seen from FIG. 1, the fibrous web is 10 following the drying cylinder 32 on a drying sieve 38 led. For the safe transfer of the paper web, the Deflecting roller 30 and drying cylinder 32 form a nip with respect to one another, i.e. be pressed against each other.

This results in a continuously closed path, and from the takeover of the fibrous web 10 by the simultaneously as Pick-up felt serving upper felt 14 from the sieve belt 16 to the handover the dryer section.

The two elongated press gaps S1, S2 are at least drained partly by centrifuging water in channels 34, 34a and 36, 36a, which can be achieved, for example, by a blind drilled and / or grooved surface of the central press roll 20 and / or a respective one blind drilled and / or grooved press jacket at least one Shoe press roll is possible.

As can be seen from FIG. 1, the rollers 20, 32 and 26 driven. From this Figure 1 also shows that in the area of Drying cylinder 32, a spray tube 53 is provided.

Figure 2 shows a schematic, partially sectioned representation Another embodiment of a press arrangement with two common ones Mating roller 20 associated with shoe press rollers 22, 24.

This embodiment differs essentially from that according to FIG. 1 in that the upper felt 28 already before the suction roll trained deflection roller 30 again by a web cutting device 52 separated from the fibrous web 10 and continued on the bottom felt 18 Fibrous web 10 in the area of the suction roll 30 through this looping dryer fabric 38 removed from the bottom felt 18 becomes. Following the deflection roller 30, the fibrous web 10 through the drying wire 38 to the first drying cylinder 32 of the following one Dryer section fed.

Otherwise, this embodiment has essentially the same Structure like that according to Figure 1, but corresponding parts are the same Reference symbols are assigned.

Figure 3 shows a purely schematic representation of an example of a possible Control of the press arrangement according to Figure 1 or 2. Here assigned to the press shoes 40, 42 of the two shoe press rolls 22, 24 Support devices 44, 46 are subjected to the same pressures p1, p2. For this purpose, the support devices 44, 46 are connected to a pressure p delivering common line 48 connected. The length L1 of the first extended press nip S1 is larger than the length in the present case L2 of the second extended press nip S2. The line forces Lk1 and Lk2 are the same size. However, the specific maximum pressures are different. Only acts on the press roll bearings of the central press roll 20 the roll weight.

Which is with a corresponding control for the two press nips S1, S2 resulting pressure profiles are purely schematic in the lower part shown in Figure 3.

FIG. 4 shows a further example of a possible activation of a respective one Press arrangement. In this case, the press shoe 40 the support device 44 assigned to the first shoe press roll 22 with a smaller pressure p1 applied than that of the press shoe 42 of the second Shoe press roller 24 associated support device 46. The two extended Press gaps S1, S2 have the same length L1, L2, i.e. it applies L1 = L2. The line force Lk1 is smaller than the line force in this case Lk2. By means of a pressure reducing valve provided in line 48 50, the pressures p1, p2 can be set separately become, i.e. only acts on the press roll bearings of the central press roll 20 the differential line force and the roll weight.

Which is with a corresponding control for the two press nips S1, S2 resulting pressure profiles are purely schematic in the lower part shown in Figure 4.

Reference list

10th

Fibrous web

12th

Suction roll

14

Top felt

16

Screen belt

18th

Bottom felt

19th

Deflection roller

20th

central press roll

22

Shoe press roll

24th

Shoe press roll

26

Deflection roller

28

Top felt

30th

Deflection roller

32

Drying cylinder

34, 34a

Gutter

36, 36a

Gutter

38

Dryer fabric

40

Press shoe

42

Press shoe

44

Support device

46

Support device

48

management

50

Valve

51

Web stop suction

52

Web cutting device

53

Spray tube

L

Web direction

L1

Gap length

L2

Gap length

Lk1

Line force

Lk2

Line force

S1

first extended press nip

S2

second extended press nip

p

print

p1

print

p2

print

Claims (20)

Press arrangement for treating a fibrous web (10), in particular a paper or cardboard web,
characterized by
that two shoe press rolls (22, 24) are assigned to a central press roll (20) serving as a common counter roll in order to form a press nip (S1, S2) elongated in the web running direction (L), and that at least that in the web running direction (L) considered first elongated press nip (S1) is double felted. Press arrangement according to claim 1,
characterized by
that the two shoe press rolls (22, 24) are arranged approximately on opposite sides of the central press roll (20). Press arrangement according to claim 1 or 2,
characterized by
that both elongated press nips (S1, S2) are each felted twice. Press arrangement according to one of the preceding claims,
characterized by
that a maximum of three felts (14, 18, 28) are provided. Press arrangement according to one of the preceding claims,
characterized by
that it has a continuously closed web guide. Press arrangement according to one of the preceding claims,
characterized by
that a felt (18) is passed through both elongated press nips (S1, S2). Press arrangement according to one of the preceding claims,
characterized by
that the fibrous web (10) between the two elongated press nips (S1, S2) formed with the central press roll is preferably guided together with a felt (18) around a deflection roll (26) which is preferably designed as a suction roll. Press arrangement according to one of the preceding claims,
characterized by
that a felt (14) passed through the first extended press nip (S1) is simultaneously provided as a pick-up felt. Press arrangement according to one of the preceding claims,
characterized by
that the fibrous web (10) following the second extended press nip (S2) is preferably guided to a subsequent dryer section via a deflection roller (30) which is preferably designed as a suction roller. Press arrangement according to claim 9,
characterized by
that the fibrous web is guided around the deflecting roller (30) together with an upper felt (28) running through the second extended press nip (S2) and is then removed from the upper felt (28) by a smooth roller (32). Press arrangement according to claim 9,
characterized by
that the fibrous web (10) is guided together with a bottom felt (18) from the second extended press nip (S2) and is removed from the bottom felt (18) in the region of the deflecting roller (30) by a drying wire (38) wrapping around it. Press arrangement according to one of the preceding claims,
characterized by
that the central press roll (20) is blind drilled and / or grooved. Press arrangement according to one of the preceding claims,
characterized by
that the drainage of the two elongated press nips (S1, S2) takes place at least in part by centrifuging water into a respective channel (34, 34a, 36, 36a) or the like. Press arrangement according to one of the preceding claims,
characterized by
that the press shoes (40, 42) of the two shoe press rolls (22, 24) associated support devices (44, 46) can be acted upon with the same pressures (p1, p2) and that the length (L1) of the first extended press nip (S1) is preferably greater is the length (L2) of the second extended press nip (S2). Press arrangement according to one of claims 1 to 13,
characterized by
that the press device (40) associated with the first shoe press roll (22) support device (44) can be acted upon with a smaller pressure (p1) than the press device (42) associated with the second shoe press roll (24) support device (46) and that the two extended Press nips (S1, S2) preferably have the same length (L1, L2). Press arrangement according to one of the preceding claims,
characterized by
that at least one of the two shoe press rolls (22, 24) has a blind-drilled and / or grooved press jacket. Press arrangement according to one of the preceding claims,
characterized by
that the central press roll (20) is an internally supported roll and is supplied with the pressures assigned to the press nips (S1, S2). Press arrangement according to one of the preceding claims,
characterized by
that the fibrous web (10) between the deflection suction roll (26) and the second press nip (S2) is additionally held on the bottom felt (18) by means of a web-holding suction device (51). Press arrangement according to one of the preceding claims,
characterized by
that the deflection roller (26) has an adjustable drive. Press arrangement according to one of the preceding claims,
characterized by
that the deflection roller (26) can also be braked with its drive in order to increase the felt tension in front of the second press nip (S2).

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