EP1676950B1 - Headbox for machine for producing a fibrous web, in particular of a paper or cardboard web - Google Patents

Abstract

A headbox for machines for making fibrous sheet, especially paper or cardboard, in which the fluid feed lines open (preferably directly) into the top, bottom and/or front of the upstream part of the intermediate compartment, which is also sub-divided by flow dividers across the machine width so as to form a first (upstream) intermediate compartment with flow channels. A headbox (1) for a machine for the production of fibrous sheet, especially paper or cardboard, with at least one distributor (2) for distributing a pulp suspension (3) over the width of the machine (MB), a guiding device (4) with numerous channels (5), another guiding device (6) with channels (7), an intermediate compartment (8) between, a headbox nozzle (9) connected to (6) and provided with an outlet gap (10) delivering a stream of pulp suspension (11), and several feed lines (12) for a fluid to be added (13), which are distributed over MB. The fluid feed lines (12) preferably open directly into the top, bottom and/or front of the upstream part (14) of compartment (8), which is also sub-divided over at least part of its length by several flow dividers (15) spread over the machine width (MB) and forming flow channels (16) so as to form at least one first (upstream) intermediate compartment (17). An independent claim is also included for a machine for the production of fibrous sheet, especially paper and/or cardboard, with a headbox (1) as described.

Description

The invention relates to a headbox for a machine for producing a fibrous web, in particular a paper or board web, with at least one distribution device for distributing at least one pulp suspension across the machine width, with a first, a plurality of channels having guide means, with a second, a A plurality of channels having guide means, with an intermediate intermediate chamber, with a adjoining the second guide means headbox, which is provided with a pulp suspension jet supplying exit slit, and with a plurality of distributed over the machine width supply lines for a zuzumischendes fluid
wherein feed lines preferably open directly on the top, bottom and / or front side in the upstream region of the intermediate chamber and wherein the intermediate chamber is divided by means of several across the machine width away and flow channels forming flow dividers at least in sections with respect to their longitudinal direction such that upstream at least a first intermediate chamber is formed ,

Such a headbox is for example from the German patent application DE 44 16 909 A1 known.

Another headbox is for example from the German Offenlegungsschrift DE 44 16 899 A1 known. In this embodiment, the admixture of the fluid with multiple distributed over the machine width supply lines directly into the machine-width intermediate chamber of the headbox. There, the added fluid streams mix with the pulp suspension to partial mixing streams. Among other things, this design has the aerodynamic disadvantage that coarse turbulence structures arise in the pulp suspension in the region of the machine-width intermediate chamber which can lead to turbulence of the individual partial mixing streams.

As part of the German patent DE 40 19 593 C2 It has been proposed that the admixture of the fluid sectionally via supply lines in the machine-width intermediate chamber upstream mixing chambers, so-called Dilution facilities to perform. However, it is disadvantageous that the divisions of the dilution devices are not independent of the number of lines. This creates an unequal response breadth.

It is therefore an object of the invention to develop a headbox of the type mentioned in such a way that it no longer has the disadvantages of the prior art. In particular, it should have a reduced and constant effective response width, effect a good mixing of the partial mixing streams in their z-direction, ensure a constancy of the partial volume flow independently of the partial fluid flow and enable retrofitting to existing systems.

This object is achieved according to the invention in that the flow dividers arranged in the intermediate chamber do not extend to the second guide device, so that at least one second intermediate chamber is formed downstream, the second intermediate chamber having a length in the range from 1 to 500 mm, preferably 10 up to 100 mm.

The object of the invention is completely solved in this way.

The top, bottom and / or end mouth of the supply lines in the upstream region of the intermediate chamber provides, among other things, a maximum of flexibility in terms of divisions of different construction and functional groups and also allows cost-effective retrofitting to existing facilities, since only minor changes, in particular attachment of Holes ("one-hole dosages") and the like, must be made on the existing system. A reduction and constant maintenance of the response range is also positively supported. The flow channels cause due to the division of the mixed streams in smaller volume partial mixing streams a good mixing of the same in their z-direction. And last but not least, a constancy of the volume partial flow is ensured independently of the partial fluid flow.

The flow divider also causes a pressure drop in the range of 01, to 5 bar, preferably from 0.2 to 1 bar, which in turn results in a largely equalization of the volume partial flows.

In a preferred embodiment it is provided that the supply lines open in the region of the first intermediate chamber on the upper side and / or the lower side in the upstream region of the intermediate chamber. As a result, the at least one pulp suspension and the admixed fluid are given the largest possible time for homogeneous mixing.

• die Zuführleitungen münden in Verlängerung und/oder annähernd in Verlängerung der Kanäle der ersten Führungseinrichtung und/oder vorzugsweise symmetrisch zwischen den Kanälen der ersten Führungseinrichtung oberseitig und/oder unterseitig in den stromaufwärtigen Bereich der Zwischenkammer;
• die Zuführleitungen münden im vorzugsweise stromaufwärtigen Bereich der Strömungskanäle der Strömungsteiler oberseitig und/oder unterseitig in den stromaufwärtigen Bereich der Zwischenkammer;
• die Zuführleitungen münden mittig oder annähernd mittig zwischen den Strömungskanälen der Strömungsteiler oberseitig und/oder unterseitig in den stromaufwärtigen Bereich der Zwischenkammer, und/oder
• die Zuführleitungen verlaufen zumindest endseitig durch die erste Führungseinrichtung hindurch und münden stirnseitig in den stromaufwärtigen Bereich der Zwischenkammer, wobei die Zuführleitungen in vorteilhafter Weise mittig oder annähernd mittig zwischen den Kanälen der ersten Führungseinrichtung hindurch verlaufen.

With regard to the mouth of the supply lines, several preferred and advantageous possibilities are proposed:

• the supply lines open in the extension and / or approximately in extension of the channels of the first guide means and / or preferably symmetrically between the channels of the first guide means on the top side and / or bottom side in the upstream region of the intermediate chamber;
• the supply lines open in the upstream region of the flow channels of the flow dividers on the upper side and / or the lower side into the upstream region of the intermediate chamber;
• the supply lines open at the center or approximately in the middle between the flow channels of the flow dividers on the top side and / or bottom side into the upstream region of the intermediate chamber, and / or
• the supply lines extend at least at the end through the first guide device and open at the end into the upstream region of the intermediate chamber, wherein the supply lines advantageously extend centrally or approximately centrally between the channels of the first guide device.

All these possibilities have in common that they optimally accomplish the supply of the fluid, still allow a homogeneous mixture of the same with the at least one pulp suspension and allow retrofitting into an existing system with little technical effort.

In a favorable embodiment, the number of supply lines is equal to or approximately equal to the number of channels of the first guide device. This ensures a direct and individual assignment of a supply line to a channel of the first guide device. A partial flow of the supplied fluid is thus assigned to a partial flow of the at least one pulp suspension. An allocation of the partial flows in the ratio of 1: 1 is provided. In this case, both the channels of the first guide device and the flow divider may have a respective pitch, which are the same, approximately the same or different.

In a further favorable embodiment, the number of flow dividers is equal to or approximately equal to the number of channels of the first guide device. With the same number, the flow dividers are preferably arranged in fluidic extension of the channels of the first guide device. This in turn ensures a direct and individual assignment of a flow divider to a channel of the first guide device.

In a third advantageous embodiment, both the flow divider and the channels of the second guide device have a respective pitch, which are the same, approximately the same or different. In one possible difference, the pitch of the channels of the second guide means is preferably a fraction of the pitch of the flow dividers. In this case, the channels of the second guide device may be aligned symmetrically to the flow dividers, so that a fluidically optimal flow path is formed.

The first intermediate chamber preferably has a length in the range of 5 to 500 mm, preferably from 10 to 100 mm, so that a sufficient length for a possible balance in terms of pressure, speed and the like is given.

Furthermore, the first guide device is preferably designed as a perforated plate, whereas the second guide device is preferably designed as a turbulence generator, which preferably has a turbulence insert with a plurality of turbulence channels, which are formed in particular by turbulence tubes. Such embodiments of the guide devices are well known in the prior art and are particularly suitable for the present embodiments.

In a further preferred embodiment, it is provided that the flow dividers forming the flow channels have at least in sections arranged structures for preferably homogeneous mixing of the respective partial mixed streams. Through these structures, the achievement of a homogeneous mixing of the supplied partial streams and pulp suspension and fluid is supported significantly positive.

Furthermore, it is advantageous if at least the flow dividers forming the flow channels at least in some areas have a turbulence-generating corrugated surface structure. Of course, the flow guide can all be arranged on the circumference of the straightening channel.

The oppositely arranged in the respective flow channel structures preferably have a preferably opposite course. This measure has a particularly advantageous effect in terms of achieving a homogeneous mixture of the two partial streams and a best possible flow calming in the partial mixing streams. In addition, the desired orientation of the partial mixing streams in the machine direction is favored.
Furthermore, the structures arranged in the flow channels comprise a plurality of flow guide elements, which are aligned at least downstream in the machine direction. This outlet-side alignment of the flow guide elements contributes significantly to the desired flow orientation of the partial mixing streams. An inlet-side alignment of the flow guide in the machine direction is desirable, but not essential.

The flow guide elements preferably have a respective element height in the range of 5 to 95%, preferably 30 to 70% of the respective clear chamber width. In this case, the element heights of at least some, preferably all flow guide elements in the machine direction can increase. These element heights require immersion of the flow guide elements in the partial mixing streams during their mixing, settling and orientation.

The arranged in a flow channel flow guide are offset in height from each other, so that it does not come to any collisions and the respective partial mixing current is continuously performed. Two adjacent flow guide elements can have a spacing in the range from 0.2 to 5 ×, preferably from 0.5 to 2 ×, of the respective clear channel width.

In order to ensure sufficient alignment of the partial mixing streams, the flow guide elements have a respective element length in the range from 1 to 20 ×, preferably from 2 to 10 ×, of the respective element height.

In the region of the flow channels additional guide means may be arranged, which contribute to the generation of a desired pressure loss in the respective flow channel.

The structures in a preferred embodiment in the form of baffles, vanes or the like. However, further fluidically suitable embodiments of the structures are of course possible.

In addition, the flow channels of the flow divider downstream preferably have a respective widening cross-section, so that a gradual transition into the machine-width second intermediate chamber, if present, is given.

The inventive machine for producing a fibrous web, in particular paper and / or board web, is characterized in that it is provided with a head box according to the invention.

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 schematische und geschnittene Draufsicht auf einen Stoffauflauf für eine Maschine zur Herstellung einer Faserstoffbahn;

Figur 2

eine teilweise Detailansicht der ersten Zwischenkammer samt angrenzenden Baugruppen der Figur 1;

Figur 3

eine teilweise Detailansicht des Stoffauflaufs der Figur 1;

Figur 4:

eine schematische Schnittdarstellung des Stoffauflaufs der Figur 1 gemäß Schnittlinie F-F;

Figuren 5a, 6a und 7a

verschiedene Ansichten eines Strömungskanals in Maschinelaufrichtung; und

Figuren 5b, 6b und 7b

verschiedene Wandansichten der Strömungskanäle der Figuren 5a, 6a und 7a.

Show it

FIG. 1

a schematic and sectional plan view of a headbox for a machine for producing a fibrous web;

FIG. 2

a partial detailed view of the first intermediate chamber, including adjacent assemblies of FIG. 1 ;

FIG. 3

a partial detail view of the headbox of the FIG. 1 ;

FIG. 4:

a schematic sectional view of the headbox of FIG. 1 according to section line FF;

FIGS. 5a, 6a and 7a

different views of a flow channel in machine direction; and

FIGS. 5b, 6b and 7b

different wall views of the flow channels of FIGS. 5a, 6a and 7a ,

The FIG. 1 shows a schematic and sectional plan view of a headbox 1 for a machine for producing a fibrous web. The fibrous web may in particular be a paper or board web.

The headbox 1 has a distributor 2 for distributing a pulp suspension 3, in particular a highly consistent pulp suspension, across the machine width MB (double arrow). The distributor 2 is in the embodiment according to FIG. 1 a transverse distribution pipe 2.1; In a further embodiment, it can also be designed as a rotary distributor with a plurality of inlet hoses. Furthermore, the headbox comprises a first, a plurality of channels 5 having guide means 4, a second, a plurality of channels 7 having guide means 6 and an intermediate chamber located therebetween 8. The second guide means 6 is followed by a headbox 9, which with a a Pulp suspension jet 11 supplying exit slit 10 is provided. In addition, the headbox 1 has a plurality of across the machine width MB (double arrow) away and only schematically shown supply lines 12 for zuzumischendes fluid 13. The fluid 13 may be a low-consistency pulp suspension, in particular white water, and / or fresh water.

The feed lines 12 now preferably open directly on the upper side into the upstream region 14 of the intermediate chamber 8 and the intermediate chamber 8 is divided by means of several across the machine width MB (double arrow) away and flow channels 16 forming flow dividers 15 at least in sections with respect to their longitudinal direction L (arrow) such that upstream of at least a first intermediate chamber 17 is formed. The flow dividers 15 divide the pulp suspension stream and optionally also the fluid stream into common individual streams.

The supply lines 12 open in the embodiment according to FIG. 1 centrally and upstream between the flow channels 16 of the flow divider 15 into the first intermediate chamber 17th

The first guide device 4 is designed as a perforated plate 18, whereas the second guide device 6 as a turbulence generator 19 (see. FIG. 4 ) is formed, which preferably has a turbulence insert 20 with a plurality of turbulence channels 21, which are formed in particular by turbulence tubes 22. The second guide means 6 designed as a turbulence generator 19 is shown only schematically, since such a turbulence generator 19 is well known in the art.

The FIG. 2 shows a partial detail view of the first intermediate chamber 17, including adjacent assemblies of FIG. 1 , namely the first guide device 4 with the channels 5, the first intermediate chamber 17 and the flow divider 15 with the flow channels 16.

This figure shows an example of the possible mouth locations of the supply lines 12, which preferably open directly on the top, bottom and / or end into the upstream region 14 of the intermediate chamber 8.

The supply line 12 may be in extension and / or approximately in extension of the channel 5 of the first guide means 4 (dashed position A) and / or preferably symmetrically between the channels 5 of the first guide means 4 (dashed position B) on the top and / or bottom in the upstream Area 14 of the intermediate chamber 8 open. Also, the supply line 12 in the preferably upstream region 23 of the Flow channel 16 of the flow divider 15 (dashed position C) open on the upper side and / or underside in the upstream region 14 of the intermediate chamber 8. It can also open centrally or approximately centrally between the flow channel 16 of the flow divider 15 (position D) on the upper side and / or the lower side in the upstream region 14 of the intermediate chamber 8. And finally, the supply line 12 can extend at least at the end through the first guide device 4 and open at the end into the upstream region 14 of the intermediate chamber 8 (dashed position E). In this case, it can run centrally or approximately centrally between the channels 5 of the first guide device 4.

The FIG. 3 shows a partial detail view of the headbox 1 of FIG. 1 ,

In this case, both the channels 5 of the first guide device 4 and the flow divider 15 have a respective pitch T _KEF , T _S , which are the same or approximately equal. Of course, the two divisions T _KEF , T _{S can} also be different. As a result of the same or approximately equal divisions T _KEF , T _S , the number of flow dividers 15 is equal to or approximately equal to the number of channels 5 of the first guide means 4. Further, the flow divider 15 are arranged in fluidic extension of the channels 5 of the first guide means 4, so that for the pulp suspension 3 baffles 24 are formed on the flow dividers 15.

Furthermore, both the flow divider 15 and the channels 7 of the second guide means 6 have a respective pitch T _S , T _KZF , which are equal or approximately equal. Of course, the two divisions T _S , T _KZF , as in the embodiment according to FIG. 3 visible, also be different. The pitch T _{KZF of} the channels 7 of the second guide means 6 is a fraction of the pitch T _{S of} the flow divider 15, more precisely half. The channels 7 of the second guide means 6 are aligned symmetrically to the flow dividers 15.

The number of supply lines 12 corresponds to the number of channels 5 of the first guide device 4 plus 1.

Furthermore, the first intermediate chamber 17 has a length L _Z1 in the range of 5 to 500 mm, preferably from 10 to 100 mm. The flow dividers 15 arranged in the intermediate chamber 8 do not extend to the second guide device 6, so that at least one second intermediate chamber 25 is formed downstream. This second intermediate chamber 25 has a length L _Z2 in the range of 1 to 500 mm, preferably from 10 to 100 mm.

The flow dividers 15 forming the flow channels 16 have structures 26 arranged at least in sections for the preferably homogeneous mixing of the respective partial mixed streams (cf. FIGS. 5a to 7b ).

In addition, the flow channels 16 downstream of a respective expanding cross-section. The extension can be continuous and / or unsteady.

The FIG. 4 shows a schematic sectional view of the headbox 1 of FIG. 1 according to section line FF. With regard to the general description of the illustrated headbox 1 is on the description of FIG. 1 directed.

It can be clearly seen that the possible supply lines 12 can preferably open into the upstream region 14 of the intermediate chamber 8, preferably directly on the upper side, the lower side and / or the front side. The over the machine width MB (arrow) away and flow channels 16 forming flow divider 15 can effectively derive forces, which act on the limiting surfaces of the channel structure, for example, by means of attached connecting elements 27, in particular screws under the prevailing requirement.

The flow dividers 15 forming the flow channels 16 have structures 26 arranged at least in sections, for preferably homogeneous mixing of the respective partial mixed streams. In this case, they have, at least in regions, a turbulence-generating corrugated surface structure 28.

The first guide device 4 is formed as a perforated plate 18, whereas the second guide device 6 is formed as a turbulence generator 19, which preferably has a turbulence insert 20 with a plurality of turbulence channels 21, which are formed in particular by turbulence tubes 22.

Furthermore, the first intermediate chamber 17 has a length L _Z1 in the range of 5 to 500 mm, preferably from 10 to 100 mm. The flow dividers 15 arranged in the intermediate chamber 8 do not extend to the second guide device 6, so that at least one second intermediate chamber 25 is formed downstream. This second intermediate chamber 25 has a length L _Z2 in the range of 1 to 500 mm, preferably from 10 to 100 mm.

The FIGS. 5a, 6a and 7a show various views of a lying between two flow dividers 15 flow channel 16 in the machine direction M (arrow), whereas the FIGS. 5b, 6b and 7b different wall views of the flow channels 16 of the FIGS. 5a, 6a and 7a demonstrate.

The flow dividers 15 forming the flow channels 16 have structures 26 arranged at least in sections, for preferably homogeneous mixing of the respective partial mixed streams. In this case, they have, at least in regions, a turbulence-generating corrugated surface structure 28, which in the flow channel 16 arranged opposite structures 26, 28 find a preferably opposite course.

The flow guide elements 29 shown in these figures have a respective element height H _S in the range of 5 to 95%, preferably 30 to 70% of the respective clear channel width B _K. In this case, the element heights H _{S of} at least some, preferably all, of the flow guide elements 29 increase in the machine direction M (arrow).

Furthermore, the flow guide elements 29 arranged in the flow channel 16 are arranged at least on the two lateral flow dividers 15. Of course, the flow guiding elements 29 can all also be arranged on the circumference of the flow channel 16. The flow guide elements 29 can also have different courses: they can be rectilinear (FIG. FIGS. 5a and 5b ), curved ( Figures 6a, 6b, 7a and 7b ) or combined.

In addition, two adjacent flow guide elements 29 have a distance G in the range from 0.2 to 5 ×, preferably from 0.5 to 2 ×, of the respective clear channel width B _K.

The arranged in a flow channel 16 flow guide 29 are equal in height ( FIG. 5a ) or offset in height ( Figures 6a and 7a ) arranged. Of course, further combinations of arrangements are possible, whether in a flow channel 16 or in a group of preferably adjacent flow channels 16.

The flow guide elements 29 have a respective element length L _S in the range from 1 to 20 times, preferably from 2 to 10 times, the respective element height H _S. The structure 26 forming the flow guide 29 have the shape of baffles, vanes or the like.
Furthermore, the structures 26 arranged opposite one another in the respective flow channel 16 have a preferably opposing course (FIG. FIGS. 6b and 7b ). In this case, the structure 26 of a flow divider 15 may have an upward course, whereas the structure 26 of the other flow divider 15 may have a downward course. The curves can be made straight or curved here.

Advantageously, the structures 26 arranged in the respective flow channel 16 have a preferably opposite course to structures arranged upstream.

Moreover, in the area of the flow channels 16, additional guide devices 30 (FIG. FIGS. 7a and 7b ) are arranged to generate a desired pressure loss in the respective flow channel 16. These guide devices 30 are generally in the channel space protruding elements of different geometry and size and they are at least individually arranged between two flow guide 29.

In summary, it should be noted that the invention provides a headbox of the type mentioned, which no longer has the mentioned disadvantages of the prior art. In particular, it has a reduced and constant effective response width, causes a good mixing of the partial mixing streams in their z-direction, ensures a constancy of the volume partial flow independent of the partial fluid flow and allows retrofitting to existing systems.

LIST OF REFERENCE NUMBERS

1

headbox

2

distributor

2.1

transverse distribution

3

Fibrous suspension

4

First management facility

5

channel

6

Second guide device

7

channel

8th

intermediate chamber

9

headbox

10

exit slit

11

Fibrous suspension beam

12

feed

13

fluid

14

Upstream area

15

flow divider

16

flow channel

17

First intermediate chamber

18

perforated plate

19

turbulence generator

20

turbulence generator

21

turbulence channel

22

turbulence tube

23

Upstream area

24

baffle

25

Second intermediate chamber

26

structure

27

connecting element

28

surface structure

29

flow guide

30

guide

A, B, C, D, E

position

B _K

channel width

F-F

intersection

G

distance

H _S

element height

L

Longitudinal direction (arrow)

L _S

element length

L _Z1

length

L _Z2

length

M

Machine direction (arrow)

MB

Machine width (double arrow)

T _KEF

division

T _KZF

division

T _S

division

Claims (30)

1. Headbox (1) for a machine for producing a fibrous web, in particular a paper or paperboard web, having at least one distribution device (2) for distributing at least one fibrous stock suspension (3) over the machine width (MB), having a first guide device (4) which has a multiplicity of channels (5), having a second guide device (6) which has a multiplicity of channels (7), having an intermediate chamber (8) which lies between them, having a headbox nozzle (9) which adjoins the second guide device (6) and is provided with an exit gap (10) which supplies a jet (11) of fibrous stock suspension, and having a plurality of feed lines (12) which are distributed over the machine width (MB) for a fluid (13) which is to be mixed in, the feed lines (12) preferably opening directly on the upper side, on the lower side and/or on the end side into the upstream region (14) of the intermediate chamber (8), and the intermediate chamber (8) being divided at least in regions with regard to its longitudinal extent by means of a plurality of flow dividers (15) which are arranged over the machine width (MB) and form flow channels (16), in such a way that at least one first intermediate chamber (17) is formed upstream, characterized in that the flow dividers (15) which are arranged in the intermediate chamber (8) do not extend as far as the second guide device (6), with the result that at least one second intermediate chamber (25) is formed upstream, the second intermediate chamber (25) having a length (L_z2) in the range from 1 to 500 mm, preferably from 10 to 100 mm.
2. Headbox (1) according to Claim 1, characterized in that, in the region of the first intermediate chamber (17), the feed lines (12) open on the upper side and/or on the lower side into the upstream region (14) of the intermediate chamber (8).
3. Headbox (1) according to Claim 2, characterized in that, as an extension and/or approximately as an extension of the channels (5) of the first guide device (4) and/or preferably symmetrically between the channels (5) of the first guide device (4), the feed lines (12) open on the upper side and/or on the lower side into the upstream region (14) of the intermediate chamber (8).
4. Headbox (1) according to one of the preceding claims, characterized in that, in the preferably upstream region (23) of the flow channels (16) of the flow dividers (15), the feed lines (12) open on the upper side and/or on the lower side into the upstream region (14) of the intermediate chamber (8).
5. Headbox (1) according to Claim 4, characterized in that, centrally or approximately centrally between the flow channels (15) of the flow dividers (15), the feed lines (12) open on the upper side and/or on the lower side into the upstream region (14) of the intermediate chamber (8).
6. Headbox (1) according to one of the preceding claims, characterized in that the feed lines (12) extend at least on the end side through the first guide device (4) and open frontally into the upstream region (14) of the intermediate chamber (8).
7. Headbox (1) according to Claim 6, characterized in that the feed lines (12) extend centrally or approximately centrally between the channels (5) of the first guide device (4).
8. Headbox (1) according to one of the preceding claims, characterized in that the number of feed lines (12) is the same as or approximately the same as the number of channels (5) of the first guide device (4).
9. Headbox (1) according to one of the preceding claims, characterized in that both the channels (5) of the first guide device (4) and the flow dividers (15) have a respective gradient (T_KEF, T_S) which are identical, approximately identical or different.
10. Headbox (1) according to one of the preceding claims, characterized in that the number of flow dividers (15) is the same as or approximately the same as the number of channels (5) of the first guide device (4).
11. Headbox (1) according to one of the preceding claims, characterized in that the flow dividers (15) are arranged in an extension, in flow terms, of the channels (5) of the first guide device (4).
12. Headbox (1) according to one of the preceding claims, characterized in that both the flow dividers (15) and the channels (7) of the second guide device (6) have a respective gradient (T_S, T_KZF) which are identical, approximately identical or different.
13. Headbox (1) according to Claim 12, characterized in that the gradient (T_KZF) of the channels (7) of the second guide device (6) is a fraction of the gradient (T_s) of the flow dividers (15).
14. Headbox (1) according to Claim 12 or 13, characterized in that the channels (7) of the second guide device (6) are oriented symmetrically with respect to the flow dividers (15).
15. Headbox (1) according to one of the preceding claims, characterized in that the first intermediate chamber (17) has a length (L_Z1) in the range from 5 to 500 mm, preferably from 10 to 100 mm.
16. Headbox (1) according to one of the preceding claims, characterized in that the first guide device (4) is configured as a perforated plate (18).
17. Headbox (1) according to one of the preceding claims, characterized in that the second guide device (6) is configured as a turbulence generator (19) which preferably has a turbulence insert (20) with a multiplicity of turbulence channels (21) which are formed, in particular, by turbulence tubes (22).
18. Headbox (1) according to one of the preceding claims, characterized in that the flow dividers (15) which form the flow channels (16) have structures (26) which are arranged at least in sections for the preferably homogeneous thorough mixing of the respective part mixing flows.
19. Headbox (1) according to Claim 18, characterized in that at least the flow dividers (15) which form the flow channels (16) have a turbulence-generating corrugated surface structure (28) at least in regions.
20. Headbox (1) according to Claim 18 or 19, characterized in that the structures (26) which are arranged opposite in the respective flow channel (16) have a profile which preferably extends in the opposite direction.
21. Headbox (1) according to one of Claims 18 to 20, characterized in that the structures (26) which are arranged in the flow channels (16) comprise a plurality of flow guiding elements (29) which are oriented in the machine running direction (M) at least on the outlet side.
22. Headbox (1) according to Claim 21, characterized in that the flow guiding elements (29) have a respective element height (H_S) in the range from 5 to 95%, preferably from 30 to 70%, of the respective inside chamber width (B_K) .
23. Headbox (1) according to Claim 22, characterized in that the element heights (H_S) of at least some, preferably all flow guiding elements (29) increase in the machine running direction (M).
24. Headbox (1) according to one of Claims 21 to 23, characterized in that the flow guiding elements (29) which are arranged in a flow channel (16) are arranged offset with respect to one another in height terms.
25. Headbox (1) according to one of Claims 21 to 24, characterized in that two adjacent flow guiding elements (29) are at a spacing (G) in the range from 0.2 to 5 x, preferably from 0.5 to 2 x the respective inside channel width (B_K).
26. Headbox (1) according to one of Claims 21 to 25, characterized in that the flow guiding elements (29) have a respective element length (L_S) in the range from 1 to 20 x, preferably from 2 to 10 x the respective element height (H_S).
27. Headbox (1) according to one of the preceding claims, characterized in that additional guiding devices (30) are arranged in the region of the flow channels (16).
28. Headbox (1) according to one of Claims 18 to 27, characterized in that the structures (26) have the form of guiding plates, guiding vanes or the like.
29. Headbox (1) according to one of the preceding claims, characterized in that the flow channels (16) have a respectively widening cross section downstream.
30. Machine for producing a fibrous web, in particular a paper and/or paperboard web, having a headbox (1) according to one of the preceding claims.

Images