EP1281805A2 - Pressing arrangement - Google Patents

Abstract

A press arrangement (10) for treating a fibrous web (12), in particular paper or cardboard web, comprises only a single shoe press, which is double felted and an elongated, at least substantially flat, formed in the web running direction (L) between two shoe press units (16, 18) Has press nip (20) through which at least one driven endless belt (22-26) is guided on both sides of the fibrous web (12). <IMAGE>

Description

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

It is already known that so-called press arrangements are also used Shoe presses with a press nip extended in the direction of web travel used (see e.g. DE-A-196 42 733, DE-A-196 44 108 and DE-C-42 02 221). In DE-A-196 42 733 is one by two shoe press rolls Shoe press formed described, which only by one by the Pressnip guided press felt web is driven.

So far, so-called tandem NipcoFlex presses were the rule two successive double felted shoe presses are provided. at These so-called tandem NipcoFlex presses are just like the so-called Ultra-NipcoFlex presses only drive one roller at a time. These known presses have the disadvantage, among other things, that in Machine direction relatively high transverse and / or shear forces in the press nip occur.

The aim of the invention is to provide an improved press arrangement at the beginning to create the type mentioned, in which, inter alia, the aforementioned Problems are eliminated.

This object is achieved according to the invention by a press arrangement with only one shoe press, which is double felted and one elongated in the web running direction between two shoe press units, has at least essentially flat press nip, by the two sides the fibrous web each has at least one driven endless Tape is performed.

Because of this design, there is a symmetrical drainage of the fibrous web in the Z direction without lateral forces and differential speeds, i.e. Slip possible in machine direction. As a result of an improved Equality, surface and volume will be optimal Paper quality reached. The investment and operating costs are on reduced to a minimum. Based on the inclusion of only a shoe press with a flat press nip into the respective Overall press concept can now be done easily and efficiently Corresponding press concepts to cover the entire basis weight range be realized. Even with a larger nip length A sufficient nip drainage capacity of, for example, about 500 mm can still be used be ensured in the shoe press.

As already mentioned, the length of the press nip of the shoe press, for example are in the range of about 500 mm.

Advantageously, the belt drive speeds are on the two Sides of the fibrous web are at least substantially the same.

The shoe press is preferably designed so that it is in the Z direction considered a symmetrical drainage of the fibrous web results.

In a preferred practical embodiment of the invention Press arrangement is the one running through the press nip of the shoe press Press plane inclined to the vertical.

The two shoe press units can each have a revolving area of the press nip guided over a press shoe flexible endless Include tape, in particular as a sealing tape of the hydraulic Shoe press rollers is executed.

In addition, a flexible press belt is guided around each shot press unit, the blind drilled and / or grooved or as a water-permeable screen fabric is executed.

The two flexible press belts are advantageously each driven.

Alternatively or additionally, at least on both sides of the fibrous web an endless felt belt passed through the press nip of the shoe press be driven.

The sealing tapes can be used in particular in combination with water-permeable Press belts (sieve belts) are also blind drilled and / or grooved his.

The press arrangement can in particular be modular. In order to can easily be used to cover a large basis weight range corresponding press concepts, each with a single, one Flat press nip extended in the direction of web travel Realize shoe press.

In an advantageous embodiment particularly suitable for light papers the fibrous web becomes the press arrangement according to the invention through a felt belt led through the press nip of the shoe press taken from a wire belt or forming wire. The relevant one can Felt belt in the area of the transfer point around a suction guide roller be led. The fibrous web is, for example, by the top felt taken from the screen belt.

According to an advantageous one particularly suitable for medium-weight paper Embodiment of the press arrangement according to the invention is the Shoe press upstream a preferably leverless pre-press, which preferably a particularly self-pressing deflection compensation roller and includes a counter roll cooperating therewith. The pre-dewatering takes place accordingly the amount of water in the shoe press. One is appropriate rewetting distance as short as possible after the pre-press.

The backing roll of the pre-press can in particular be a press suction roll be educated.

It is also advantageous if the fibrous web is preferably in the region of one height-adjustable pickup roller through a through the press nip The pre-roll felt belt is taken over by a wire belt. By doing the pickup roller is preferably adjustable accordingly, is one universal adaptation of this pickup roller to the screen height possible. there the fibrous web can hang freely on the pick-up felt up to the pre-press.

The pre-press expediently embodied without crowning comprises preferably a single-zone deflection compensation roller with freely movable Jacket, i.e. a so-called single-zone Nipco-F roller, whereby an optimal felt and web run is achieved.

According to another advantageous one, particularly suitable for heavy paper Embodiment of the press assembly according to the invention the shoe press is preceded by a preferably leverless pre-press, which a deflection compensating roller and one cooperating with it Counter roller includes, which also serves as a pickup roller, in the Area the fibrous web is taken over by a screen belt. You get a NipcoCombi pre-press and a subsequent one Flachnip shoe press.

Pre-dewatering using the leverless NipcoCombi pre-press in particular brings a corresponding reduction in the amount of water in the shoe press with it. The remoistening in the following The distance is relatively short for heavy varieties.

This press arrangement with NipcoCombi pre-press is preferred the so-called screen drive roller (compare, for example, roller 98 in Fig. 2) pivotally arranged. The NipcoCombi pre-press can be used for Adaptation to the existing sieve height can be arranged at any height. The fibrous web can, in particular, reach the transfer point in the sandwich be arranged.

The backing roll of the pre-press is preferably by a press suction roll formed, which can also fulfill a pickup function.

There is no web waste, especially with heavy papers.

In certain cases it is advantageous if the pre-press has a steam blow box assigned.

The last-mentioned pre-press is again preferably without crowning executed and with a single-zone deflection compensation roller provided with a freely movable jacket, which results in an optimal Felt and web run results.

In combination with all of the previously mentioned variants, you can choose following the first drying cylinder of the paper machine in question an offset press may be provided, which is preferably free-standing is.

All variants have a safe web exit in the press pulper on the first drying cylinder. Before and after the offset press the fibrous web is specifically guided with a short free train.

With the preferably compact, free-standing offset press that is Transfer action relieved.

The web preheating on the first drying cylinder is expected to better smoothness can be achieved with low line force.

The preferably leverless offset press can in particular be without Crowning carried out and with a single-zone deflection compensation be provided with a freely movable jacket. With one single-zone Nipco-F roller results in an inexpensive, leverless offset press with variable line force for optimal offset operation and Web travel.

The driven flexible press belts can in particular be water-storing or have water permeability, i.e. e.g. be blind drilled and / or grooved or designed as screen mesh.

In particular, sealing tapes can be used to seal the shot press units be provided on the surface e.g. smooth or blind drilled and / or can be grooved.

With the press arrangement according to the invention with a single, in particular large flat nip shoe press can be a straight, long nip up for example, about 500 mm can be realized. Because of the straight Press nips with belt drive on both sides do not generate shear forces in the machine direction and no slip in the sandwich passed through the nip on. The alternating bending stress of the sealing tapes or the press or Sieve belts of the shoe press units are reduced, which results in result in longer terms. The sealing tape or press tape stress or dent at the end of the roll is reduced: there is a higher nip dewatering capacity through the additional drainage function reached due to the driven press belts or fabric belts, whereby there is a large application window for a mono shoe press. The building load and crane capacity are limited. After one Shoe press unit with a flexible press belt is lighter than a so-called Nipco-P roller, a correspondingly larger shoe press unit can be provided be what brings a longer nip length. There are fewer reserve rollers required. So no Nipco-P roller has to be kept in reserve become. The respective coverings are optimal on each other Voted. The lower rotating mass of the flexible belts enables a quick stop in the event of an accident.

Fig. 1

eine schematische Darstellung einer insbesondere für leichte Papiere geeigneten Variante einer Pressenanordnung,

Fig. 2

eine schematische Darstellung einer weiteren, insbesondere für mittelschwere Papiere geeigneten Variante der Pressenanordnung, und

Fig. 3

eine schematische Darstellung einer weiteren, insbesondere für schwere Papiere geeigneten Variante der Pressenanordnung.

The invention is explained in more detail below using exemplary embodiments with reference to the drawing. In this show:

Fig. 1

1 shows a schematic representation of a variant of a press arrangement which is particularly suitable for light papers,

Fig. 2

2 shows a schematic representation of a further variant of the press arrangement, particularly suitable for medium-weight papers, and

Fig. 3

is a schematic representation of another, particularly suitable for heavy papers variant of the press arrangement.

1 to 3 show different, purely exemplary variants of a Press arrangement 10 for treating a fibrous web 12, in which it can in particular be a paper or cardboard web.

The respective press arrangement 10 comprises only a single double felted shoe press with a between two shoe press units 16, 18th formed in the web running direction L extended, at least substantially flat press nip or nip 20. This is extended, flat Press nip 20 on both sides of the fibrous web 12 at least one driven endless belt 22 to 26 guided.

The length of the press nip 20 of the shoe press 14 can, for example, in Range of about 500 mm.

The belt drive speeds on both sides of the fibrous web are preferably at least substantially the same.

In all variants, the shoe press 14 can in particular be designed in this way be considered symmetrical drainage in the Z direction the fibrous web 12 results.

As can be seen from FIGS. 1 to 3, the press nip 20 of the respective shoe press 14 running press plane 30 against the Vertical 32 be inclined. In the present cases, the angle of inclination is α for example in the range of about 25 °.

The two shoe press units 16, 18 each comprise a rotating, guided in the area of the press nip 20 via a press shoe 34 or 36 Band 94, 96 and a flexible endless belt 22 and 24, in particular designed as a water-storing or water-permeable press belt can be. In the present case, these flexible bands 22, 24 each have a non-circular cylindrical course, with them over guide rollers 38 and 40 are guided and the relevant shoe press units 16, 18 can be open at the side. Basically, the shoe press units but also by shoe press rolls with a respective sealing jacket 94, 96 may be formed, which are sealed at their ends.

As can be seen from FIGS. 1 to 3, the two are flexible Belts 22, 24 each driven, for which purpose at least one guide roller, for example 38 or 40, can be driven accordingly.

In all variants of the press assembly 10 is through the press nip 20 of the shoe press 14 each have a lower felt belt 26 and an upper one Felt tape 28 out. 1 to 3 can be seen, in the present case, these two felt belts 26, 28 are each also driven. For this purpose, a corresponding guide roller 22 or 44 be driven.

The press assembly 10 is modular, so that each the desired variant can be easily implemented.

The web discharge following the shoe press 14 can, for example, in each case via a drying sieve assigned to the first drying cylinder 46 48 take place in the area of a suction roll 50, via which the dryer fabric 48 is guided to the fibrous web 12, for example from the lower Take over felt belt 26 and feed it to the drying cylinder 46.

1, particularly suitable for light papers Variant of the press arrangement 10 is the fibrous web 12 by a felt belt guided by the press nip 20 of the shoe press 14, in the present case If the upper felt belt 28 is taken over by a sieve belt 52. This felt strip 28 is in the area of the takeover point by one Suction guide roller 54 guided, which is driven in the present case.

In the case of the one shown in FIG. 2, in particular for medium-weight papers A suitable variant of the press arrangement 10 is the shoe press 14 preferably upstream leverless press 56. This pre-press 56 in the present case comprises a deflection compensation roller 58 and a counter roller 60 cooperating with the counter roller 60 can be formed in particular by a press suction roll.

The pre-press 56 can, in particular, be designed without crowning and with a single-zone deflection compensation roller 58 with freely movable Coat.

The lower felt belt 26 of the shoe press 14 is above the counter roller 60 guided. The deflection compensation roller 58 is inside the loop another felt belt 62 is arranged. Through the press nip of this pre-press 56 are thus the lower one with the fibrous web 12 in between Felt belt 26 of the shoe press 14 and the further felt belt 62 guided.

The fibrous web 12 is preferably adjustable Pick-up roller 64 through the guided by the press nip of the roughing roller 56 Felt belt 62 taken from the wire belt 52.

The result of the preliminary dewatering in the leverless Nipco pre-press 56 a corresponding reduction in the amount of water in the shoe press 14. After the pre-press 56 is a short remoistening distance in which the paper on the bottom felt 26 is fed to the press nip 20 becomes. It is a universal adaptation of the pickup roller 64 to the Height of the sieve belt 52 possible. The fibrous web 12 hangs freely on Pick-up felt belt 62 up to the pre-press 56. The result is an optimal one Felt and web run, the pre-press 56, as already mentioned, without Crowning and be provided with a single-zone Nipco-F roller 58 can.

3, particularly suitable for heavy papers The shoe press 14 is preferably a variant of the press arrangement 10 upstream leverless press 66, which has a deflection compensation roller 68 and a counter roller cooperating with this 70 includes, which also serves as a pickup roller, in the area of which Fibrous web 12 is taken over by the wire belt 52. In this Fall is the deflection adjustment roller 68 within the loop of the lower screen belt 26 of the shoe press 14 and the counter roller 70 within the loop of another felt band 74 is arranged. By the Press nip of this pre-press 66 are thus with the fibrous web in between 12 the lower felt belt 26 of the shoe press 14 and the further felt belt 74 out.

The counter roll 70 of the pre-press 66 can in particular be a combi press suction roll be educated. The pre-press 66 is preferably again executed without crowning and with a single-zone deflection compensation roller 68 provided with a freely movable jacket.

The counter roller 70 is preferably adjustable again.

As can be seen from FIG. 3, the pre-press 66 can be a steam blow box 76 can be assigned.

Following the pre-press 66, the two felt belts 26, 74 are one Piece widely led vertically upward to within an area the suction guide roller 78 arranged in the loop of the felt belt 26 to be separated from each other. The fibrous web 12 is then subsequently through the lower felt belt 26 the extended flat press nip the shoe press 14 fed.

In the following case, this results in a NipcoCombi pre-press 66 and one following flat-nip shoe press 14. Pre-drain through the leverless pre-press 66 brings a corresponding reduction in Amount of water in the shoe press. The rewetting at heavy varieties is relatively small. With the height-adjustable pickup roller 70 or NipcoCombi pre-press 66 is a universal adaptation to the height of the sieve belt 52 possible. The fibrous web 12 is up to Transfer point in the area of the suction guide roller 78 with the felt belts 26 and 74 sandwich formed. Also with those in question here heavy papers, there is no web waste. The order steam box 76 is purely optional. With the NipcoCombi pre-press 66 without crowning and with single-zone Nipco-F roller 68 results an optimal felt and web run.

In all of the variants of the press arrangement described above 10 can follow the first drying cylinder 46 of the relevant Paper machine an offset press 80 with short paper draws after the Drying cylinder 46 may be provided.

With all variants there is a safe web discharge in the press pulper possible on the drying cylinder 46. The fibrous web 12 can before and after the offset press 80 each be guided with a short free train.

The preferably leverless offset press 80 can in particular be without Crowning carried out and with a single-zone deflection compensation roller 82 be provided with a freely movable jacket. With all Variants result from the compact, free-standing offset press 80 an easier transfer handling. By preheating the web on the drying cylinder 46 is expected to have better smoothness with low line force can be achieved. With the single-zone Nipco-F roller 82, this results an affordable, lever-free offset press 80 with variable line force without crowning for optimal offset operation and web running.

For example, it is also a combination, in particular, of the ones shown in FIGS. 2 and 3 press arrangements shown for example for expansion of the insert window of an Ultra-NipcoFlex press possible.

As can be seen from FIGS. 1 to 3, the drying cylinder 46 assigned at least one scraper 84.

From the lower roller, again provided with a scraper 86 88 of the offset press 80, the fibrous web 12 is in the area of a Screen guide roller 90 taken over by a further dryer screen 92 that the web 12 is fed to the subsequent drying group 72, which is, for example, a so-called "DuoRun" can.

LIST OF REFERENCE NUMBERS

10

Press arrangement

12

Fibrous web

14

shoe press

16

shoe press

18

shoe press

20

press nip

22

driven endless belt, flexible belt, press or screen belt

24

driven endless belt, flexible belt, press or screen belt

26

driven flexible belt, lower felt belt

28

driven flexible belt, upper felt belt

30

press plane

32

vertical

34

press shoe

36

press shoe

38

guide roll

40

guide roll

42

driven guide roller

44

driven guide roller

46

first drying cylinder

48

dryer

50

suction roll

52

screen belt

54

suction guide

56

pre-press

58

Deflection roll

60

backing roll

62

Filzband

64

Pickup roll

66

pre-press

68

Deflection roll

70

backing roll

72

drying group

74

Filzband

76

steam blow

78

suction guide

80

Offset press

82

Deflection roll

84

scraper

86

scraper

88

roller

90

wire guide roll

92

dryer

94

sealing tape

96

sealing tape

98

wire drive

L

Web direction

Claims (29)

Press arrangement (10) for treating a fibrous web (12), especially paper or cardboard web, with only one Shoe press (14), which is double felted and one between two Shoe press units (16, 18) formed in the web running direction (L) has an elongated, at least substantially flat press nip (20), by at least on both sides of the fibrous web (12) a driven endless belt (22-26) is guided. Press arrangement according to claim 1,
characterized in that the length of the press nip (20) of the shoe press (14) is in the range of approximately 500 mm. Press arrangement according to claim 1 or 2,
characterized in that the belt drive speeds on the two sides of the fibrous web (12) are at least substantially the same. Press arrangement according to one of the preceding claims,
characterized in that the shoe press (14) is designed such that, when viewed in the Z direction, there is symmetrical dewatering of the fibrous web (12). Press arrangement according to one of the preceding claims,
characterized in that the pressing plane (30) extending through the press nip (20) of the shoe press (14) is inclined with respect to the vertical (32). Press arrangement according to one of the preceding claims,
characterized in that the two shoe press units (16, 18) each comprise a circumferential flexible endless belt (22, 24) which is guided in the region of the press nip (20) via a press shoe (34, 36) and is in particular designed as a sealing tape. Press arrangement according to claim 6,
characterized in that in addition a flexible press belt is guided around each shoe press unit (16, 18) and is blind-drilled and / or grooved or designed as a water-permeable screen fabric. Press arrangement according to claim 7,
characterized in that the two flexible press belts (22, 24) are each driven. Press arrangement according to one of the preceding claims,
characterized in that the sealing tapes are blind-drilled and / or grooved, particularly in combination with water-permeable press tapes (sieve tapes). Press arrangement according to one of the preceding claims,
characterized in that on both sides of the fibrous web (12) at least one driven endless felt belt (26, 28) is guided through the press nip (20) of the shoe press (14). Press arrangement according to one of the preceding claims,
characterized in that it is modular. Press arrangement according to one of the preceding claims,
characterized in that the fibrous web (12) is taken over by a wire belt (52) through a felt belt (28) guided through the press nip (20) of the shoe press (14). Press arrangement according to claim 12,
characterized in that the felt belt (28) in question is guided around a suction guide roller (54) in the area of the takeover point. Press arrangement according to claim 12 or 13,
characterized in that the fibrous web (12) is taken over by the upper belt (28) from the wire belt (52). Press arrangement according to one of claims 1 to 11,
characterized in that the shoe press (14) is preceded by a preferably lever-free pre-press (56), which preferably comprises an in particular self-pressing deflection compensation roller (58) and a counter-roller (60) cooperating therewith. Press arrangement according to claim 15,
characterized in that the counter roll (60) of the pre-press is formed by a press suction roll. Press arrangement according to claim 15 or 16,
characterized in that the fibrous web (12) in the region of a preferably height-adjustable pickup roller (64) is taken over by a wire belt (52) through a felt belt (62) guided through the press nip of the pre-roll (56). Press arrangement according to one of the preceding claims,
characterized in that the pre-press (56) is designed without crowning and comprises a single-zone deflection compensation roller (58) with a freely movable jacket. Press arrangement according to one of claims 1 to 11,
characterized in that the shoe press (14) is preceded by a preferably lever-free pre-press (66) which comprises a deflection compensation roller (68) and a counter-roller (70) which interacts with it and which at the same time serves as a pick-up roller, in the area of which the fibrous web ( 12) is taken over by a sieve belt (52). Press arrangement according to claim 19,
characterized in that the counter roll (70) of the pre-press (66) is adjustable in height. Press arrangement according to claim 19 or 20,
characterized in that the counter roll (70) of the pre-press (66) is formed by a press suction roll. Press arrangement according to one of claims 19 to 21,
characterized in that the pre-press (66) is associated with a steam blow box (76). Press arrangement according to one of claims 19 to 22,
characterized in that the pre-press (66) is designed without crowning and comprises a single-zone deflection compensation roller (68) with a freely movable jacket. Press arrangement according to one of the preceding claims,
characterized in that an offset press (80) is provided following the first drying cylinder (46). Press arrangement according to claim 24,
characterized in that the offset press is free-standing. Press arrangement according to claim 24 or 25,
characterized in that the fibrous web (12) is guided before and after the offset press (80) with a short free train. Press arrangement according to one of claims 24 to 26,
characterized in that the preferably leverless offset press (80) is designed without crowning and comprises a single-zone deflection compensation roller (82) with a freely movable jacket. Press arrangement according to one of the preceding claims,
characterized in that the driven flexible press belts (22, 24) have a water-storing or water-permeable property, that is to say, for example, they are blind-drilled and / or grooved or designed as a sieve fabric. Press arrangement according to one of the preceding claims,
characterized in that sealing tapes (94, 96) are provided for sealing the shoe press units (16, 18), which are preferably smooth or blind-drilled and / or grooved on the surface.

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