EP1911877A2 - Apparatus and method for manufacturing a fibrous web - Google Patents

Abstract

The invention relates to a device for producing a fibrous web (10), in particular a paper web, with a headbox (3; 40) and further components such as a former (4), a press section (14), a drying section (21,29) and in particular a coating device (25 ) and / or calenders (34).

The device according to the invention is characterized in that the headbox (3; 40) has a nozzle (7; 41) which has several layers (S1, S2, S1, S2, S3) on partial pulp suspensions (2.1, 2.2; 2.1, 2.2, 2.3) , wherein the partial pulp suspensions (2.1, 2.2, 2.1, 2.2, 2.3) are formed at least in part from one and the same pulp suspension (2) such that the dryer section (21, 29) comprises at least one single-row dryer group (22, 30) and the configuration and / or the operation of the headbox (3; 40) alone or in combination with the design and / or operation of at least one further component (21, 22) is selected such that a desired profile of the layer orientation in the z-direction with respect to a curl influence of the fibrous web (10).

Furthermore, the invention relates to a corresponding method for producing a fibrous web (10).

Description

The invention relates to a device for producing a fibrous web, in particular paper web, with a headbox and other components such as former, press section, dryer section and in particular coater and / or calender.

Furthermore, the invention relates to a method for producing a fibrous web, in particular paper web, in which a pulp suspension is introduced by means of a headbox in a former and then further treated by means of other components such as press section, dryer section and in particular coater and / or calender.

In the production of a fibrous web, in particular a wood-free copy paper, it is particularly important that the finished fibrous web has little or no tendency to curl, curl, curl and the like in terms of performance in the subsequent copying process. The curl is caused, for example by a Umklimatisierung the fibrous web. By heat during the copying process, the moisture content of the fibrous web and thus also of the fibers is reduced. The fibers shrink and create stresses in the fibrous web which cause curling when the fibrous web is asymmetrically heated. So far, it has been attempted to compensate for this tendency to curl in the production process of the fibrous web by an asymmetric heating course in the production machine by means of two-row drying groups. But this was only insufficient.

If the fibrous web, in particular the paper web in the z-direction, ie in the direction of the sheet thickness, is subdivided into different layers, then each layer has a more or less pronounced anisotropy with respect to the fiber orientation in the plane. The layers may each have main layers of fiber layers, which are characterized in that a certain number of fibers are aligned in the same direction. Fibrous main directions may point exactly in the machine main direction or across it or in directions therebetween. How many fibers point in a common direction is expressed in the degree of anisotropy. High anisotropy means that many fibers are oriented in one direction and vice versa. The anisotropy of the fiber layers also significantly determines the anisotropy of the mechanical properties, e.g. the in-plane strength anisotropy. The anisotropy or the degree of anisotropy may be different in the layers. Then one speaks of a non-constant profile of the layer orientation measured over the sheet thickness, ie in the z-direction.

A measure of the different layer orientation in the z-direction can be, for example, the ratio of the tenacial length ratios of the upper half of the sheet to the lower half of the sheet. This measure should be in the range of 0.8 to 1.2 at the end of the paper machine. The tenacity ratio, called RLV in technical circles, is the ratio of the tear length in the machine direction (MD direction) and the tear length in the cross machine direction (CD direction). This can be determined for the entire fibrous web or, after splitting the fibrous web in layers, also for each layer.

A profile of the layer orientation manifests itself in particular in a two-sidedness, that is to say a different layer orientation on the upper side of the sheet and on the lower side of the sheet. Such a two-sidedness can arise due to the asymmetrical structure of the headbox nozzles. In the flow deflection at the diaphragm, the fibers are increasingly aligned in the machine direction. On the opposite lower lip side finds an alignment in Machine direction due to the increased microturbulence only limited. Also by the former, the press section and the dryer section in a paper machine, a two-sidedness of the layer orientation between the upper side of the sheet and the lower side of the sheet can be generated.

The invention has the object to improve a device and a method of the type mentioned. In particular, the properties of the fibrous web, in particular the curl of the fibrous web, should be improved.

This object is achieved in a device of the type mentioned above in that the headbox has a plurality of layers of pulp stock suspensions leading nozzle, the pulp partial suspensions are at least partially formed from one and the same pulp suspension, that the dryer section comprises at least one single-row drying group, and that the design and / or the operation of the headbox alone or in combination with the design and / or operation of at least one further component is selected so that there is a desired profile of the layer orientation in the z-direction with respect to a curl influencing the fibrous web.

The inventors have recognized that the headbox, the former, the press section, the dryer section and other components of the production machine have different effects on the structure of the fibrous web with regard to curl tendency. While the headbox and the former can mainly negatively affect the fiber layer of the fibrous web, the press section, for example, has an effect on the composition of the fibrous web in the z-direction. For example, a different ratio of fibers and fillers on the top and bottom of the fibrous web may adversely affect curl due to these structural differences.

The inventors have found that this can not be corrected by the known measures, such as the adaptation of the heating curve in the dryer section. Rather, the headbox offers the possibility of correcting the layer orientation by shaping its flow space a correction, so that in later use of the fibrous web minimal or no curl occurs more.

It has also been found that when the transfer from one component of the production machine to the other, the trains or expansions of the fibrous web negatively influence the structure of the fibrous web with regard to curl behavior.

According to the invention, it is therefore proposed to selectively use the known influence of the headbox and at least one further constituent on the profile of the layer orientation by combining a headbox with a specific influence on this profile with at least one further constituent whose influence on said profile is influenced by the influence Counteracts or supports headbox, depending on whether according to a preferred embodiment of the invention, a symmetrical to the median plane of the fibrous web layer orientation is desired or in certain cases an asymmetric layer orientation. For example, an asymmetric layer orientation may be preferred or chosen for certain types of paper to compensate for an influence of another component of the paper machine on the profile of the layer orientation.

The selection is preferably made so that there is a symmetrical to the center plane in the z direction of the fibrous web layer orientation. In this case, the selection is preferably made such that a desired, preferably no curl tendency in the fibrous web results before the coater and / or that a desired, preferably no curl tendency results in the finished fibrous web. Furthermore, at least one further component of the Considering the device in terms of its influence on the profile of the layer orientation in the selection.

The at least one further component is in a preferred embodiment, the single-row dryer group of the pre-dryer section of the dryer section, as this allows a better runnability and a higher production speed of the device.

In order to effect the asymmetric layer orientation, the headbox can in particular have an asymmetrical nozzle and / or an asymmetric lamellar arrangement with preferably different layer speeds in the nozzle leading to several layers of pulp stock suspensions. The different layer speeds also result in a different layer orientation, since the fiber orientation also increases with increasing flow velocity.

A symmetrical layer orientation through the headbox can be achieved, in particular, by the headbox having a symmetrical nozzle and a symmetrical lamellar arrangement with preferably different layer speeds in the nozzle guiding several layers of pulp stock suspensions or an asymmetrical nozzle and a correspondingly inversely asymmetrical lamination arrangement with preferably different layer speeds in the comprising several layers of pulp part suspensions leading nozzle. As already mentioned, an increased flow velocity or shear flow leads to a higher orientation of the fibers, so that a lower orientation of the fibers can be compensated by the geometrical configuration of the headbox in a layer by a correspondingly increased flow velocity in this layer.

Furthermore, the individual layers guided in the nozzle have jet velocity differences between 0 and 100 m / min, preferably between 0 and 60 m / min, and the ratio of the tenacity ratios (sheet anisotropy) from top to bottom half of the fibrous web is preferably between 0.7 and 1.3, preferably between 0.8 and 1.2, adjustable. The tenacity ratio, called RLV in technical circles, is the ratio of the tear length in the machine direction (MD direction) and the tear length in the cross machine direction (CD direction). This can be determined for the entire fibrous web or, after splitting the fibrous web in layers, also for each layer.

The former of the device according to the invention is in a preferred embodiment, a twin-wire former, either in a design of a roll-blade former or in a design of a blade-roll former, wherein a curved fixed element is provided with strips or perforation as the first dewatering unit. The first-mentioned embodiment advantageously has a forming roller and formation strips which can be pressed against a forming shoe. With both embodiments, a fibrous web having a desired layer orientation can be selectively produced, and this even at higher production speeds in the range of ≥ 1500 m / min, in particular ≥ 1.650 m / min.

Also, different press concepts can be provided for the press section of the device according to the invention. Thus, the press section can comprise at least one press nip with a double-felted shoe press for uniform drainage, it can have two press nips, wherein the first press nip comprises a double-felted nip or shoe press and the second press nip comprises a single- or double-felted shoe press, or even one 3-nip press with a first double-felted press and two subsequent single-felted presses running against a central roll.

Furthermore, as a coating device of the device according to the invention a Speedsizer for preferably two-sided and indirect application of a liquid or pasty medium, preferably glue provided. The application of glue reduces, for example, the dusting of the copy paper in the copier.

The drying section preferably has a post-drying section after the coating device, which comprises at least one single-row drying group. As mentioned earlier, a single tier dryer group promotes better runnability and higher production speed of the device. And at the end of the after-dryer section, a water application unit acting on the underside of the fibrous web is preferably provided which preferably has zone-controlled nozzles which use air or steam to atomize the water or the condensate.

As a preferably last component before the reeling, a calender may be provided which has at least one soft-nip calender with a heated roll and a softer and related roll for smoothing the fibrous web. In this case, the soft-nip calender is preferably equipped with at least one, preferably acting on the underside of the fibrous web steam blower box.

In a method of the type mentioned above, the object is achieved in that the headbox is configured with a nozzle leading to multiple layers of pulp stock suspensions, wherein the pulp stock suspensions are at least partially formed from one and the same pulp suspension that configured the dryer section with at least one single-row dryer group and that the design and / or the operation of the headbox alone or in combination with the design and / or operation of at least one further component is chosen so that there is a desired profile of the layer orientation in the z-direction with respect to a curl influencing the fibrous web ,

This results in the aforementioned advantages according to the invention.

The selection is preferably made so that a symmetrical to the median plane in the z direction of the fibrous web layer orientation results. In this case, the selection is preferably made so that a desired, preferably no Curl inclination in the fibrous web and / or that forms a desired, preferably no Curl inclination in the finished fibrous web before the coater. Furthermore, at least one further component of the device can be taken into account with regard to its influence on the profile of the layer orientation in the selection.

In a particularly practical embodiment of the method according to the invention, the single-row dryer group of the pre-dryer section of the dryer section is chosen as the at least one further component since this allows better runnability and a higher production speed of the device.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings.

Figur 1

eine vorteilhafte Konfiguration der erfindungsgemäßen Vorrichtung für die Herstellung von curlarmen und holzfreien Kopierpapieren;

Figuren 2a bis 14a

verschiedene Varianten eines Stoffauflaufs,

Figuren 2b bis 14b

die jeweils zugehörige Verteilung der Layerorientation auf der Papierober- und -unterseite; und

Figuren 15a bis 15d

weitere verschiedene Varianten eines Stoffauflaufs mit einem jeweils direkt angeflanschten Verteilrohr.

It shows

FIG. 1

an advantageous configuration of the device according to the invention for the production of curlarmen and wood-free copy papers;

FIGS. 2a to 14a

different variants of a headbox,

FIGS. 2b to 14b

the respective associated distribution of the layer orientation on the paper top and bottom side; and

FIGS. 15a to 15d

other variants of a headbox with a directly flanged manifold.

An exemplary and advantageous configuration 1 for the production of curlar and wood-free copying papers with a high specific volume is shown in FIG. Configuration 1 is four in total Partial representations shown, which are marked with the following arrows A, B and C in terms of their sequence.

The pulp suspension 2 is supplied via a two-layer headbox 3 a former 4 in a design of a twin-wire former 5, wherein in each layer S1, S2 of the headbox 2, a pulp suspension 2.1, 2.2 is supplied, which are at least partially formed from one and the same pulp suspension 2. Of course, further substances can be added to the respective fibrous material suspension 2.1, 2.2.

The headbox 3 further comprises a rigid separator blade 6, which protrudes from the preferably symmetrical nozzle 7 and thus divides it into two halves. Each half is fitted with flexible blades 8 between each row of tubes of the associated turbulence generator T1, T2. The flexible blades 8 are arranged symmetrically and terminate within the nozzle 7, wherein moreover two orifices 9.1, 9.2 are provided.

The headbox 3 can also have an asymmetrical nozzle and / or an asymmetric lamellar arrangement with, preferably, different layer speeds in the nozzle leading to several layers of pulp stock suspensions. In this case, the asymmetry of the nozzle and / or the lamellae can be compensated for by different layer speeds of the partial pulp suspensions.

Furthermore, the individual layers S1, S2 of the headbox 3 have jet velocity differences ΔV _beam between 0 and 100 m / min, preferably between 0 and 60 m / min. Thus, the ratio of the sheet anisotropy from top to bottom half of the fibrous web 10 is adjustable between 0.7 and 1.3, preferably between 0.8 and 1.2.

The former 4 comprises a forming roll 11 and a forming shoe 12, which are not arranged on the same side. So he is a twin-wire 5 in Design of a roll-blade former. Against Formierschuh 12 more formation strips 13 are pressed.

The former 4 can also be a double-wire former in a design of a blade-roll former in a non-illustrated embodiment, wherein a curved fixed element with strips or perforation is provided as the first dewatering unit.

After the former 4, the fibrous web 10 is transferred to a press section 14. The press section 14 consists of a first nip press 15 with overhead and deflection-controlled roller 16 and bottom suction roll 17. The second and last press nip is formed by a single or double-felted shoe press 18.

However, the press section 14 can also have only one press nip with a double-felted shoe press for uniform dewatering or a 3-nip press with a first double-felted press and two subsequent single-sided felted presses running against a central roll.

The fibrous web 10 is now with a transfer belt 19 to a so-called impingement drying device 20, as for example from the already mentioned German Offenlegungsschrift DE 10 2004 039 785 A1 is known, transferred. The advantage here is the closed web guide up to a dry content of over 60% or 63%. This allows a high production speed for this fibrous web 10 of ≥ 1,500 m / min, in particular ≥ 1,650 m / min.

This is followed by a known single-row pre-dryer section 21 with several dryer groups 22. Essential for high production speeds is a supported web guide equipped with stabilizers 23 between the drying cylinders 24.

Subsequent to the pre-drying section 21, at least one coater 25 for preferably two-sided and indirect application of a liquid or pasty medium 26.1, 26.2, in particular glue. The application of glue 26.1, 26.2 reduces, for example, the dusting of the copy paper in the copier. The coating device 25 may be, for example, a known in the art Speedsizer.

After a non-contact deflection 27 and drying 28 of the coated fibrous web 10 is followed by a post-dryer section 29, which includes both single-row dryer groups 30 and two-row dryer groups 31. With the help of the double-row dryer group 31, a symmetrical drying of the double-sided glue application can be achieved. A slightly different application of glue on the two sides of the fibrous web 10 would lead to different Trocknungsverläufen and thus in turn to Curlneigung. Curl is an important characteristic for copying papers and describes the curl tendency of the sheet during copying.

At the end of the after-dryer section 29 there is provided a water application unit 32 acting on the underside of the fibrous web 10, which preferably uses zone-controlled nozzles 33 which use air or steam to atomize the water or the condensate.

This is followed by a calender 34, which has two soft-nip calenders 35.1, 35.2, each with a heated roller 36 and a softer and related roller 37 for smoothing the fibrous web 10. At least one of the softnip calenders 35.1, 35.2 is equipped with at least one steam blower box 38, preferably acting on the underside of the fibrous web 10.

And finally there is a preferably winding tension controlled / regulated and surface-sparing reeling of the fibrous web 10 in a winding machine 39.

The configuration 1 shown in FIG. 1 is outstandingly suitable for carrying out the method according to the invention for producing a fibrous web 10, in particular a paper web, in which a pulp suspension is introduced by means of a headbox 3 into a former 4 and subsequently by means of further components such as press section 14, dryer section 21, 29, coater 25 and / or calender 34 is further treated.

Furthermore, the configuration 1 can be suitably combined with the headbox variants shown in the following FIGS. 2a to 14a and 15a to 15d.

The illustrated in Figure 2a first variant of a headbox 40 has an asymmetrical nozzle 41 with a diaphragm 42 on the top and a protruding bottom lip 43 on the bottom. In addition, the headbox 40 of this first variant has symmetrically arranged lamellae 44.

In the figure 2b is shown that results from such a design of the headbox asymmetric layer orientation, namely a high anisotropy in the upper half 45 and a lower anisotropy in the lower half 46 of the fibrous web. That is, the fibers in the upper half 45 have a fiber layer main direction, while in the lower half 46 no such direction is preferred.

In the second headbox variant according to FIG. 3 a, the nozzle configuration is identical to that of FIG. 2 a. In contrast to the first variant, however, the fins 44 are arranged asymmetrically here. As shown in FIG. 3 b, the combination of an asymmetric nozzle 41 with inversely asymmetrical lamellae 44 results in a symmetrical layer orientation.

In the variants of Figures 4a and 5a, both the nozzles 41 and the fins 44 are formed symmetrically. Accordingly, as shown in FIGS. 4b and 5b, a symmetrical layer orientation results.

The same applies to the variant of FIG. 6 a, which differs from the variant according to FIG. 4 a only by an additional flexible separating element 47 in the center of the headbox 40. FIG. 6b again shows the symmetrical layer orientation. Thus, the headbox 40 leads two layers S1, S2 to partial pulp suspensions 2.1, 2.2, which are formed at least in part from one and the same pulp suspension.

The variant of FIG. 7 a also has a flexible separating element 47. However, the nozzle design here is asymmetrical, so that as shown in Figure 7b, results in an asymmetric layer orientation.

FIG. 8a shows a further variant, which differs from the variant according to FIG. 7a only in that here the lamellae 44 are inversely arranged asymmetrically. As a result, the asymmetrical design of the nozzle is compensated so that, according to FIG. 8b, a symmetrical layer orientation results.

The configuration of the device according to the invention may make it necessary to even increase the asymmetry in FIG. 7a. This can be achieved by using longer lamellae 44 in the lower half of the nozzle 41 than in the upper half of the nozzle 41.

FIG. 9a largely corresponds to FIG. 6a. The flexible separating element 47 of FIG. 6 a is merely replaced by a rigid separating element 48. Consequently, according to FIG. 9b, too, a symmetrical layer orientation results.

Rigid separators are generally used to separate the die space into at least two die subspaces in which different pressures can be maintained for the purpose of generating different jet velocities, respectively.

FIG. 10a differs from the variant according to FIG. 9a by an asymmetric lamellar arrangement, so that, according to FIG. 10b, an asymmetrical layer orientation also results.

FIG. 11a again shows a variant with a rigid separating element 48, in which an asymmetrical nozzle 41 is combined with inversely asymmetrical lamellae 44, so that a symmetrical layer orientation results.

The preferably long and short lamellae 44 in the two nozzle subspaces of the nozzle 41 move in certain length ranges relative to the corresponding aperture 42.1, 42.2, in particular in the case of the continuously convergent nozzles. The long sipes 44, either flexible or stiff, bend in the range of +/- 30 mm towards the baffle tip. The short fins 44 are shorter in all cases. They are preferably in the range of less than -30 to -150 mm, in particular in the range of less than -50 to -100 mm.

FIG. 12a shows a variant with rigid separating element 48, asymmetric nozzle 41 and symmetrical lamellae 44. This results in an asymmetrical layer orientation.

FIG. 13a again shows the variant of FIG. 9a, wherein it is additionally shown here according to arrows 49 and 50 that the flow velocities v1 and v2 in the upper half of the headbox 40 and in the lower half of the headbox 40 can be chosen differently. FIGS. 13b1, 13b2 and 13b3 show how the layer orientations are set as a function of the speed ratios. FIG. 13b1 shows the case that the If the speeds v1 and v2 are equal, FIG. 13b2 is the case where the speed v1 in the upper half of the headbox 40 is greater than the speed v2 in the lower half of the headbox 40 and FIG. 13b3 is the opposite case. Accordingly, according to FIG. 13b1, a symmetrical layer orientation results, according to FIG. 13b2 an asymmetrical layer orientation with high anisotropy in the upper half of the fibrous web and according to FIG. 13b3 an asymmetric layer orientation with high anisotropy in the lower half of the fibrous web.

FIG. 14a shows a further variant of a headbox 40 with two rigid separating elements 48. Thus, the headbox 40 carries three layers S1, S2, S3 of partial pulp suspensions 2.1, 2.2, 2.3, which are formed at least in part from one and the same pulp suspension. Accordingly, three different speeds v1, v2 and v3 can be set. If all velocities v1 to v3 are set the same, the result is a uniform layer orientation across the thickness of the fibrous web, as shown in FIG. 14a. By appropriate different choice of the speeds v1 to v3, the layer orientation can be selected in the desired manner, in particular also different on the top 51, the bottom 52 and in the center 53 of the fibrous web 10th

Finally, FIGS. 15a to 15d show further different variants of a headbox with a respective directly flanged distribution tube. The supply of the respective system thus takes place from a manifold.

In the headbox 40 shown in FIG. 15a, different flow velocities v1, v2 in the individual layers S1, S2 can be set by the position of the separating lamella 55, and thus the layer orientation can be influenced. In the layers S1, S2 pulp partial suspensions 2.1, 2.2 are guided, which are formed at least partially from one and the same pulp suspension.

The flow rates in the individual layers can be adjusted in different ways. On the one hand, the friction conditions of the flow in the individual layers of the nozzle can be influenced. For example, as indicated by the double arrow 54 in FIG. 15a, by means of a pivoting of the separating blade 55 out of the neutral position and / or by a change in the flow resistances in the respective turbulence generators T1, T2 upstream of the nozzle. This is particularly advantageous when both layers are supplied by a distributor tube.

It is also conceivable to supply each layer separately with pulp suspension, for example via separate distributor tubes. The throughput is controlled or regulated in both cases.

It is also possible to influence the layer orientation via the setting of different beam contractions in the two layers, for example by setting different aperture boards and / or different aperture angles.

Also conceivable are length-adjustable lamellae and / or variable-shape lamellae for the targeted change of the fluid friction conditions for changing the flow velocities in the respective layers and thus for adjusting the layer orientation. Long lamellae increase the friction and thereby support the anisotropy of the fiber layer, as well as a possible thickening of a lamella and the resulting constriction of a flow channel.

In the case of the headbox with rigid separating lamella 56 shown in FIG. 15b, different flow velocities in the individual layers can be set by the position of the lip supports 57, 58 and thus the layer orientation can be influenced. The positioning of the lip supports 57, 58 can be done for example by a respective pivoting (double arrows 59, 60) when changing the lip openings.

By varying the flow rate, the existing driving pressure gradient is more or less displaced into the nozzle. This results in different jet speeds. For example, increasing the gap opening by 5% (5% throughput reduction) increases the pressure loss by 10.25% in one shift. At a pressure drop of 500 mbar, this means a pressure reduction of 50 mbar. This achieves, depending on the jet speed, for example at 1200 m / min, a relevant change in the differential speed, for example about - 15 m / min.

The headbox shown in FIG. 15c basically represents a combination of the headboxes of FIGS. 15a and 15b. A change in the pressure loss in the turbulence generator T1, T2 can be achieved by actively changing the flow cross section, for example by inserting or replacing inserts, by slides and / or or by valves, of one or more lines in one layer or both layers. Preferably, the control is performed on one side of a line, since the flow differences in the percentage range at the nozzle start are not relevant, have a strong impact in the area of sheet formation in the percent range. The control of the jet velocity is carried out by a dynamic pressure control by pressure transmitter in each layer.

And in the headbox shown in Figure 15d is a development of the headbox shown in Figure 15c. The illustrated headbox also has a known to the expert white water dosing system 61, as for example in the German patent DE 40 19 593 C2 is described.

LIST OF REFERENCE NUMBERS

1

configuration

2

Fibrous suspension

2.1

Pulp suspension part

2.2

Pulp suspension part

2.3

Pulp suspension part

3

Two-layer headbox

4

molder

5

twin

6

separating lamella

7

jet

8th

lamella

9.1

cover

9.2

cover

10

Fibrous web

11

forming roll

12

forming shoe

13

formation bar

14

press section

15

Nip press

16

roller

17

suction press

18

shoe press

19

transfer tape

20

Impingement drying device

21

pre-dryer

22

drying group

23

stabilizer

24

drying cylinders

25

coater

26.1

medium

26.2

medium

27

redirection

28

desiccation

29

Afterdryers

30

Single tier dryer group

31

Double row drying group

32

Water commissioned

33

jet

34

calender

35.1

Soft nip calender

35.2

Soft nip calender

36

roller

37

roller

38

steam blow

39

winder

40

headbox

41

jet

42

cover

42.1

cover

42.2

cover

43

bottom lip

44

lamella

45

Upper half

46

Bottom half

47

Flexible separator

48

Rigid separating element

49

arrow

50

arrow

51

top

52

bottom

53

center

54

double arrow

55

separating lamella

56

separating lamella

57

lip carrier

58

lip carrier

59

double arrow

60

double arrow

61

Siebwasserdosierungssystem

A

follow arrow

B

follow arrow

C

follow arrow

S1

layer

S2

layer

S3

layer

T1

turbulence generator

T2

turbulence generator

v1

flow rate

v2

flow rate

v3

flow rate

ΔV _beam

Jet speed difference

Claims (28)

Apparatus for producing a fibrous web (10), in particular a paper web, with a headbox (3; 40) and further components such as a former (4), press section (14), dryer section (21, 29) and in particular coater (25) and / or Calender (34),
characterized,
in that the headbox (3; 40) has a nozzle (7; 41) which has multiple layers (S1, S2; S1, S2, S3) and partial pulp suspensions (2.1, 2.2; 2.1, 2.2, 2.3), the partial pulp suspensions (2.1, 2.2, 2.1, 2.2, 2.3) 2.2, 2.1, 2.2, 2.3) are formed at least in part from one and the same pulp suspension (2),
that the drying section (21, 29) comprises at least one single-row drying group (22, 30), and
that the configuration and / or the operation of the headbox (3; 40) alone or in combination with the design and / or the operation of at least one further component (21, 22) is selected so that a desired profile of the layer orientation in z. Direction with respect to a Curlbeeinflussung the fibrous web (10) results. Device according to claim 1,
characterized,
that the selection is made so that a symmetrical to the center plane in the z direction of the fibrous web (10) layer orientation results. Apparatus according to claim 1 or 2,
characterized,
that the selection is made such that a desired, preferably no curl tendency in the fibrous web (10) results before the coater (25). Apparatus according to claim 1, 2 or 3,
characterized,
that the selection is such that a desired, preferably no curl tendency results in the finished fibrous web (10). Device according to one of the preceding claims,
characterized,
that at least one further component of the device is taken into account with regard to its influence on the profile of the layer orientation in the selection. Device according to one of the preceding claims,
characterized,
that the at least one further component of the single-tier dryer group (22) of the pre-dryer section (21) of the dryer section. Device according to one of the preceding claims,
characterized,
in that the headbox (3; 40) has an asymmetrical nozzle (7; 42; 42.1, 42.2) and / or an asymmetric disk arrangement with preferably different layer speeds (v1, v2, v3) in which a plurality of layers (S1, S2, S1, S2, S3) on pulp partial suspensions (2.1, 2.2, 2.1, 2.2, 2.3) leading nozzle (7, 42, 42.1, 42.2). Device according to one of claims 1 to 6,
characterized,
in that the head box (3; 40) has a symmetrical nozzle (7; 41) and a symmetrical lamellar arrangement with preferably different layer speeds (v1, v2, v3) in the several layers (S1, S2; S1, S2, S3) of pulp stock suspensions (2.1 , 2.2, 2.1, 2.2, 2.3) or an asymmetric nozzle and an inverted asymmetrical lamellar arrangement with preferably different layer speeds in which several layers of pulp partial suspensions leading nozzle. Device according to one of the preceding claims,
characterized,
in that an asymmetry of the nozzle (42, 42.1, 42.2) and / or the lamellae (44) is compensated for by different layer velocities (v1, v2, v3) of the pulp partial suspensions (2.1, 2.2, 2.3). Device according to one of the preceding claims,
characterized,
that the individual layers (S1, S2; S1, S2, S3) jet velocity differences (Δ _V-ray) between 0 and 100 m / min, preferably between 0 and 60 m / min, having. Device according to one of the preceding claims,
characterized,
in that the ratio of the sheet anisotropy from the upper side to the lower half (45, 46) of the fibrous web (10) is adjustable between 0.8 and 1.2. Device according to one of the preceding claims,
characterized,
that the former (4) is a twin-wire (5) in an embodiment of a roll-blade former. Device according to claim 12,
characterized,
in that the twin-wire former (5) has a forming roller (11) and formation strips (13) which can be pressed against a forming shoe (12). Device according to one of claims 1 to 11,
characterized,
that the former is a twin-wire former in the form of a blade-roll former, wherein a curved fixed element with strips or perforation is provided as the first dewatering unit. Device according to one of the preceding claims,
characterized,
in that the press section has at least one press nip with a double-felted shoe press for uniform drainage. Device according to one of claims 1 to 14,
characterized,
in that the press section (14) comprises two press nips, wherein the first press nip comprises a double-felted nip press (15) or shoe press and the second press nip comprises a single or double-felted shoe press (18). Device according to one of claims 1 to 14,
characterized,
that the press section has a 3-nip press with a first double-felted press and two subsequent single-felted presses running against a central roll. Device according to one of the preceding claims,
characterized,
in that the coating device (25) has a speed sizer for applying a liquid or pasty medium (26.1, 26.2), preferably glue. Device according to one of the preceding claims,
characterized,
in that the drying section has an after-dryer section (29) comprising at least one single-row drying section (30). Device according to claim 19,
characterized,
in that at the end of the after-dryer section (29) there is provided a water application unit (32) acting on the underside of the fibrous web (10), which preferably uses zone-controlled nozzles (33) which use air or steam to atomize the water or the condensate Device according to one of the preceding claims,
characterized,
in that the calender (34) has at least one soft-nip calender (35.1, 35.2) with a heated roll (36) and a softer and related roll (37; 41) for smoothing the fibrous web (10). Device according to claim 21,
characterized,
that the soft nip calender (35.1, 35.2) with at least one, preferably on bottom of the fibrous web (10) acting steam blower box (38) is equipped. Method for producing a fibrous web (10), in particular a paper web, in which a pulp suspension (2) is introduced into a former (4) by means of a headbox (3; 40) and subsequently by means of further components such as press section (14), dryer section (21, 29 ) and in particular coating device (25) and / or calender (34) is treated further,
characterized,
in that the headbox (3; 40) is configured with a nozzle (7; 41; 42; 42.1, 42.2) which has multiple layers (S1, S2, S1, S2, S3) and partial pulp suspensions (2.1, 2.2, 2.1, 2.2, 2.3) is, wherein the pulp partial suspensions (2.1, 2.2, 2.1, 2.2, 2.3) are at least partially formed from one and the same pulp suspension (2),
that the drying section (21, 29) is configured with at least one single-row drying group (22, 30), and
that the design and / or the operation of the headbox (3; 40) alone or in combination with the design and / or operation of at least one further component is selected such that a desired profile of the layer orientation in the z-direction with respect to a curl influence Fiber web (10) results. Method according to claim 23,
characterized,
that the selection is made such that a symmetrical to the center plane in the z direction of the fibrous web (10) layer orientation results. Method according to claim 23 or 24,
characterized,
that the selection is made such that a desired, preferably no curl tendency in the fibrous web (10) results before the coater (25). A method according to claim 23, 24 or 25,
characterized,
that the selection is made such that a desired, preferably no curl tendency results in the finished fibrous web (10). Method according to one of claims 23 to 26,
characterized,
that at least one further component of the device is taken into account with regard to its influence on the profile of the layer orientation in the selection. Method according to one of claims 23 to 27,
characterized,
in that the one-row dryer group (22) of the pre-dryer section (21) of the dryer section is selected as the at least one further component.

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