DE102011081312A1 - Twin-wire former for a machine for producing a fibrous web from at least one pulp suspension - Google Patents

Abstract

The invention relates to a twin - wire former (1) for a machine (100) for producing a fibrous web (2) from at least one pulp suspension (3), comprising two continuous endless sieves (4, 5), of which the first sieve (4) has a Peripheral region (7) of at least one forming element (6) runs and the second sieve (5) over a peripheral region (9) of a guide element (8) and then in the region of the forming element (6) on the first sieve (4) to form a wedge-shaped Stoffeinlaufspalts (10), directly from a headbox (11) which receives at least one pulp suspension (3) accumulates, the two wires (4, 5) with the at least one between them pulp suspension (3) in the wire direction (S) at least in sections form a double-wire zone (12), wherein in the region of the twin-wire zone (12) and one another of the forming element (6) a forming suction box (13) with a preferably curved forming surface (13 .F) is arranged, which consists of a plurality of spaced apart and rigid strips (14) over which the two wires (4, 5) are guided with the at least one fibrous suspension (3) between them, and in the direction of wire (S) at least one forming zone (15) which can be acted upon by a preferably controllable / controllable negative pressure (pu).

Description

The invention relates to a twin-wire former for a machine for producing a fibrous web from at least one pulp suspension, with two circumferential endless screens, of which the first sieve over a peripheral region of at least one forming element, in particular a forming roll or both a guide element, in particular a breast roll and a rigid , curved and suctioned impingement shoe runs and the second wire over a peripheral region of a guide element, in particular a breast roll runs and then in the region of the forming element on the first sieve to form a wedge-shaped material inlet gap, which immediately from a headbox receives the at least one pulp suspension accumulates, the two sieves with the at least one fibrous suspension between them in the direction of wire stretching then at least partially form a double-wire zone, wherein in the region of the twin-wire zone and each other of the Fo a Formiersaugkasten with a preferably curved Formierfläche is arranged, which consists of a plurality of spaced apart and rigid strips, over which the two wires are guided with the at least one located between them pulp suspension, and in the direction of wire direction at least one with a preferably controllable / Forming zone acted upon underpressure forms, and the two screens with the at least one between them pulp suspension in the direction of wire run thereafter via a separator, preferably a curved and evacuated separating element, in particular a roller or a stationary suction extractor run, in which case the second sieve of the at least one is separated on the first wire to be produced fibrous web.

Such a twin-wire former is for example from the document DE 198 03 591 A1 known.

The respectively in the 1 to 3 and 6 The disclosed twin-wire former has, after screen separation, ie after the separation of one screen, in particular the second screen, from the fibrous web to be produced on the other screen, a screen suction roller. The use of such a suction sieve causes high acquisition and operating costs. An acquisition cost of considerable height has to be applied for the suction sieve roll (operating roll and a reserve roll). Moreover, the extraction of the suction sieve designed consuming and therefore high operating costs due to increased energy and maintenance costs. In addition, the gutter leads to Siebsaugwalze double doubling not inconsiderable high costs.

It is therefore an object of the invention to develop a twin-wire former of the type mentioned in such a way that an energy-efficient drainage without Siebsaugwalze is made possible with sufficient sieve or process stability. It should also be the production of a fibrous web with a production speed of over 1,800 m / min, preferably of over 1,500 m / min, ie the highest speed potential, but no disadvantages in terms of achievable product quality and runnability, possible.

This object is achieved in a twin-wire former of the aforementioned type according to the invention that the first sieve with the fibrous web thereon produced thereafter via a preferably not directly sucked through the roll shell guide roll at a roll wrap of at least 25 °, preferably of at least 35 °, in particular of at least 45 °, is guided and that between one of the guide roller of each other of the first sieve in the direction of wire sieve subsequent pickup roller for the decrease of the fibrous web to be produced and the guide roller at least one preferably controllable / controllable suction element, in particular a suction box is arranged.

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

The inventive provision of a preferably not directly sucked through the roll shell, so no holding forces generating guide roll with sufficient Walzenumschlingung and downstream in Sieblaufrichtung suction, in particular suction box ensures energy-efficient drainage with adequate sieve or process stability. From the use of a hitherto used and the disadvantages described sieve suction can therefore be dispensed with altogether. In addition, the production of a fibrous web with a production speed of over 1,800 m / min, preferably of over 1,500 m / min, ie with the highest speed potential possible, and this without any disadvantages in terms of achievable product quality and runnability.

The preferably not directly drawn through the roll shell guide roll preferably has a grooved, blind drilled, drilled or otherwise structured surface structure. Such a surface structure of the guide roller effectively prevents floating due to a possible fluid absorption and thus a bleeding of the first sieve with overlying fibrous web to be produced in this former region. The first sieve is thus reliably stabilized in its barrel. For this purpose, the guide roller, in particular the surface structure of the guide roller also preferably has an open surface of ≥ 20%, preferably ≥ 30%, in particular ≥ 40%.

In a preferred embodiment, the forming element is a forming roll having a roll diameter in the range of from 1,000 to 2,500 mm, preferably from 1,500 to 2,000 mm, in particular from 1,700 to 1,900 mm. In this case, the two wires extend with the at least one fibrous suspension between them in one of the forming roller downstream in the wire direction of the double-wire zone at an angle of 10 to 50 °, preferably from 20 to 40 °, in particular from 25 to 35 °, to an imaginary vertical plane downward. The forming roller ensures a fast and efficient initial drainage of the introduced pulp suspension and the course down brings, inter alia, the advantage of a shortened, but still efficient drainage of the introduced pulp suspension. The twin-wire zone may extend down to an imaginary vertical plane immediately after the end of the first wire from the forming roller in a limited range at an angle of> 0 to 45 °, preferably from> 0 to 30 °, in particular from> 5 to 15 ° ,

Furthermore, between the arranged in the wire loop of the second screen Formiersaugkasten and disposed in the wire loop of the first screen separator, preferably the curved and evacuated separating element, in particular the roller or the stationary separating sucker, preferably a deflection device, preferably a deflecting element, in particular a guide roller, arranged in the wire loop of the second screen. After this deflection, the two wires extend with the at least one fibrous suspension between them at an angle, preferably at an angle of> 0 to 45 °, in particular at an angle of 5 to 25 °, to an imaginary horizontal plane upwards. Among other things, the deflection device and the subsequent upward course provide the advantage of a markedly shortened, but still efficient, dewatering of the incorporated pulp suspension.

And in a preferred alternative embodiment, the forming element is a rigid, curved and suctioned impingement shoe having a shoe length of 200 to 2,000 mm, preferably 300 to 1,500 mm, especially 400 to 1,200 mm. In this case, the two wires extend with the at least one fibrous suspension between them in an impingement shoe in the direction of wire downstream of the double-wire zone at an angle of> 0 to 45 °, preferably from 5 to 25 °, to an imaginary horizontal plane upwards. This impingement shoe also ensures fast and efficient initial drainage of the introduced pulp suspension and the course upwards provides, inter alia, the course of a shortened, but still efficient drainage of the introduced pulp suspension.

In both preferred embodiments, in the at least one forming zone, opposite the forming suction box and in the wire direction at a distance from the leading edge of the first rigid strip of the Formiersaugkastens at least two arranged between each two adjacent and rigid strips of Formiersaugkastens formation strips are provided, which are supported by means of resilient elements and which are pressed with a selectable force against the touching first sieve. This embodiment has a positive effect on improving the formation in the fibrous web to be produced, in particular due to the introduction of shear forces.

Alternatively and / or additionally, preferably at least one deflector is provided in the at least one forming zone, opposite the forming suction box and in the direction of wire run at a distance from the leading edge of the first rigid strip of the forming suction box. This embodiment also has a positive effect on improving the formation in the fibrous web to be produced, in particular due to the introduction of shear forces.

Furthermore, the rolls of the twin-wire former according to the invention are preferably designed such that the sum of all roll deflections in the web or machine center of the rolls, resulting from a total load, in particular a total operating load, including, inter alia, the wire tension and the dead weight, ≤ 10 mm, preferably ≤ 7 mm, in particular ≤ 5 mm, is. The guide roller according to the invention, which is not sucked through the roll shell, has the disadvantage of a loss of adhesion with respect to the wire, ie a reduction in screen stability. In order for this disadvantage to be made up for the most part again, the sieve must be stabilized otherwise. One way of stabilizing the screen is in the mentioned type of allowable sum of the roll deflections.

Also, the ratio of the difference of the length of a respective wire loop from edge to center, based on the total length of this wire loop, is preferably ≦ 5%, preferably ≦ 4%, in particular ≦ 3%.

Of course, a machine for producing a fibrous web, in particular a paper, cardboard or Packaging paper web from at least one pulp suspension be provided with at least one twin-wire former according to the invention.

Here, the twin-wire former is preferably arranged downstream of a press section with at least one press unit, in particular a shoe press, preferably directly in the machine or wire feed direction. Such a press section leads to a further and marked increase in the dry content of the fibrous web to be produced at a reasonable cost and acceptable quality disadvantages.

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

Show it

1 to 3 schematic side views of preferred embodiments of a respective twin-wire former according to the invention for a machine for producing a fibrous web; and

4 a schematic representation of the forces acting on its rollers during operation of the Doppelsiebformers invention.

The 1 to 3 show schematic side views of preferred embodiments of a respective twin-wire former 1 for a machine, not shown 100 for producing a fibrous web 2 (dashed line) of at least one pulp suspension 3 , In the produced fibrous web 2 in particular, it is an at least single-layered paper, cardboard or packaging paper web.

The respective twin-wire former 1 includes two continuous endless sieves 4 . 5 of which the first sieve 4 over a peripheral area 7 both a known guide element, in particular a breast roll and a forming element 6 running. The second sieve 5 however, it runs over a peripheral area 9 a guide element 8th , in particular a breast roll 8.1 and thereafter in the region of the forming element 6 on the first sieve 4 forming a wedge-shaped material inlet gap 10 , directly from a headbox 11 the at least one pulp suspension 3 picks up.

The two sieves 4 . 5 with the at least one fibrous suspension between them 3 form in Sieblaufrichtung S (arrow) then at least in sections a twin-wire zone 12 , In the area of this twin-wire zone 12 and each other of the forming element 6 is a well-known Formiersaugkasten 13 , in professional circles also referred to as Obersiebsaugkasten, with a preferably curved Formierfläche 13.F arranged. It consists of several spaced and rigid strips 14 over which the two sieves 4 . 5 with the at least one fibrous suspension between them 3 are guided. Moreover, in the direction S of the sweeping direction S (arrow), it forms at least one forming zone which can be acted upon by a preferably controllable negative pressure pu 15 out. The preferably controllable negative pressure pu in the forming zone 15 is by means known to a person skilled in the art and only schematically indicated negative pressure source 16 generated.

Then the two sieves run 4 . 5 with the at least one fibrous suspension between them 3 in wire direction S (arrow) via a separating device 17 , preferably a curved and evacuated separating element 17.1 , In particular, a roller, not shown, or a stationary vacuum cleaner shown. This is the second sieve 5 from the at least one on the first sieve 4 located and produced fibrous web 2 separated.

Now the first sieve 4 with the fibrous web thereon and to be produced 3 preferably not directly through the roll shell 18.M suctioned guide roller 18 in a roll wrap 18.U of at least 25 °, preferably of at least 35 °, in particular of at least 45 °. And between one of the guide rollers 18 each other of the first sieve 4 in sieve direction S (arrow) following pickup roller 19 for the decrease of the fibrous web to be produced 3 and the guide roller 18 is a preferably controllable suction element 20 , in particular a suction box 20.1 arranged. Of course, a plurality of preferably controllable / suction elements, in particular suction boxes in this area of the Doppelsiebformers 1 be provided.

The preferably not directly through the roll shell 18.M suctioned guide roller 18 on the one hand has a grooved, blind drilled, drilled or otherwise structured surface structure 18.S , on the other hand, an open area 18.F of ≥ 20%, preferably ≥ 30%, in particular ≥ 40%.

In the two embodiments of the 1 and 2 is the forming element 6 a forming roller 6.1 that have a roll diameter 6.1d in the range of 1,000 to 2,500 mm, preferably from 1,500 to 2,000 mm, in particular from 1,700 to 1,900 mm.

Continue to run the two sieves 4 . 5 with the at least one fibrous suspension between them 3 in one of the forming roll 6.1 in Sieblaufrichtung S (arrow) downstream area of the twin-wire zone 12 at an angle A of 10 to 50 °, preferably from 20 to 40 °, in particular from 25 to 35 °, to an imaginary vertical plane V down.

The twin-wire zone 12 moreover, it runs immediately after the expiration of the first sieve 4 from the forming roll 6.1 in a limited range at an angle of> 0 to 45 °, preferably from> 0 to 30 °, in particular from> 5 to 15 °, down to an imaginary vertical plane.

Between that in the sieve loop of the second sieve 5 arranged Formiersaugkasten 13 and the one in the sieve loop of the first sieve 1 arranged separation device 17 is a deflection device 21 , preferably a deflecting element 21.1 , in particular a guide roller, in the wire loop of the second wire 5 arranged. Furthermore, the two screens run 4 . 5 with the at least one fibrous suspension between them 3 after the deflection device 21 , preferably the deflecting element 21.1 , in particular the guide roller, at an angle B, preferably at an angle B of> 0 to 45 °, in particular at an angle B of 5 to 25 °, to an imaginary horizontal plane H upwards.

Also, in the embodiment of the 1 in the forming zone 15 Opposite the forming suction box 13 and in the wire direction S (arrow) at a distance C to the leading edge of the first rigid bar 14 of the Formiersaugkastens 13 at least two between each two adjacent and rigid strips 14 of the Formiersaugkastens 13 arranged formation strips 22 provided by means of yielding elements 23 are supported and with a selectable force 23.K (Arrow) against the touching first sieve 4 are pressed. Instead of the formation bar 22 can of course also a known to the expert deflector (see. 2 ) find its use.

On the other hand, in the embodiment of the 2 in the forming zone 15 Opposite the forming suction box 13 and in the wire direction S (arrow) at a distance C to the leading edge of the first rigid bar 14 of the Formiersaugkastens 13 at least one deflector 24 intended. Instead of the deflector 24 can of course also known to a person skilled and flexible contactable Formationsleiste (see. 1 ) find their use.

In the embodiment of the 3 is the forming element 6 a rigid, curved and suctioned impingement shoe 6.2 with a shoe length 6.2L from 200 to 2,000 mm, preferably from 300 to 1,500 mm, in particular from 400 to 1,200 mm.

Continue to run the two sieves 4 . 5 with the at least one fibrous suspension between them 3 in an impingement shoe 6.2 in Sieblaufrichtung S (arrow) downstream area of the twin-wire zone 12 at an angle D of> 0 to 45 °, preferably from 5 to 25 °, to an imaginary horizontal plane H upwards.

Also, in the embodiment of the 3 in the forming zone 15 Opposite the forming suction box 13 and in the wire direction S (arrow) at a distance C to the leading edge of the first rigid bar 14 of the Formiersaugkastens 13 at least two between each two adjacent and rigid strips 14 of the Formiersaugkastens 13 arranged formation strips 22 provided by means of yielding elements 23 are supported and with a selectable force 23.K against the touching first sieve 4 are pressed.

The 4 shows a schematic and exemplary illustration of the during operation of a twin-wire former 1 forces acting on its rollers. The individual rolls are independent of their roll type (forming roll, guide roll, guide roll, guide roll, etc.) consistently provided with the letter W and the individual acting forces are represented as a function of their effective size and effective direction by a bar and consistently provided with the letter K. ,

The rollers W of the twin-wire former according to the invention 1 are now designed such that the sum of all roll deflections in the web or machine center of the rolls W, resulting from a total load, in particular a total operating load, including, inter alia, the wire tension and the dead weight, ≤ 10 mm, preferably ≤ 7 mm, in particular ≤ 5 mm, is.

Furthermore, the ratio of the difference of the length of a respective wire loop, formed from the respective sieve 4 . 5 , from edge to center based on the total length of this wire loop ≤ 5%, preferably ≤ 4%, in particular ≤ 3%.

The in the 1 to 4 in each case schematically and at least partially illustrated twin-wire former according to the invention 1 is particularly suitable for use in a machine 100 for producing a fibrous web 2 , in particular a paper, cardboard or packaging paper web of at least one pulp suspension.

Here is the twin-wire former 1 preferably directly downstream in machine or Sieblaufrichtung a known to those skilled press section with at least one press unit, in particular a shoe press downstream.

In summary, it should be noted that a twin-wire former of the type mentioned above is further developed by the invention so that an energy-efficient drainage without Siebsaugwalze is made possible with sufficient Sieb- or process stability. It is also possible to produce a fibrous web with a production speed of over 1,800 m / min, preferably of more than 1,500 m / min, ie with the highest speed potential, but without any disadvantages with regard to achievable product quality and runnability.

LIST OF REFERENCE NUMBERS

1

twin

2

Fibrous web

3

Fibrous suspension

4

First sieve

5

Second sieve

6

forming element

6.1

forming roll

6.1d

Roll diameter

6.2

Impingementschuh

6.2L

Shoe length

7

peripheral region

8th

vane

8.1

breast roll

9

peripheral region

10

Stock inlet gap

11

headbox

12

twin

13

Formiersaugkasten; top wire suction

13.F

Formierfläche

14

strip

15

forming zone

16

Vacuum source

17

separator

17.1

Separating element; suction separator

18

guide roll

18.F

Open area

18.M

roll shell

18.S

surface structure

18.U

roll wrap

19

Pickup roll

20

suction

20.1

suction box

21

deflecting

21.1

deflector; deflecting

22

formation bar

23

Resilient element

23.K

Selectable force

24

deflector

100

Machine for producing a fibrous web

A

angle

B

angle

C

distance

D

angle

H

WL

K

Force (bar)

pu

vacuum

S

Sieblaufrichtung (arrow)

V

vertical plane

W

roller

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19803591 A1 [0002]

Claims (12)

Twin wire former ( 1 ) for a machine ( 100 ) for producing a fibrous web ( 2 ), in particular a paper, board or packaging paper web of at least one pulp suspension ( 3 ), with two continuous endless sieves ( 4 . 5 ), of which the first sieve ( 4 ) over a peripheral area ( 7 ) at least one forming element ( 6 ), in particular a forming roller ( 6.1 ) or both a guide element, in particular a breast roll and a rigid, curved and suctioned Impingementschuhs ( 6.2 ) and the second sieve ( 5 ) over a peripheral area ( 9 ) of a guiding element ( 8th ), in particular a breast roll ( 8.1 ) and then in the region of the forming element ( 6 ) on the first sieve ( 4 ) to form a wedge-shaped material inlet gap ( 10 ) directly from a headbox ( 11 ) the at least one pulp suspension ( 3 ), runs up, the two sieves ( 4 . 5 ) with the at least one fibrous suspension between them ( 3 ) in Sieblaufrichtung (S) then at least in sections a twin-wire zone ( 12 ), wherein in the region of the twin-wire zone ( 12 ) and each other of the forming element ( 6 ) a Formiersaugkasten ( 13 ) with a preferably curved forming surface ( 13.F ), which consists of a plurality of mutually spaced and rigid strips ( 14 ), over which the two sieves ( 4 . 5 ) with the at least one fibrous suspension between them ( 3 ) are guided, and in the screen direction (S) at least one with a preferably controllable negative pressure (pu) acted upon forming zone ( 15 ), and the two sieves ( 4 . 5 ) with the at least one fibrous suspension between them ( 3 ) in Sieblaufrichtung (S) then via a separator ( 17 ), preferably a curved and evacuated separating element ( 17.1 ), in particular a roller or a stationary vacuum cleaner, wherein the second sieve ( 5 ) of the at least one on the first sieve ( 4 ) and to be produced fibrous web ( 2 ), characterized in that the first sieve ( 4 ) with the fibrous web thereon and to be produced ( 2 ) thereafter via a preferably not directly through the roll shell ( 18.M ) suctioned guide roller ( 18 ) in a roll wrap ( 18.U ) of at least 25 °, preferably of at least 35 °, in particular of at least 45 °, is guided and that between one of the guide roller ( 18 ) mutually the first sieve ( 4 ) in Sieblaufrichtung (S) following pickup roller ( 19 ) for the decrease of the fibrous web to be produced ( 2 ) and the guide roller ( 18 ) at least one preferably controllable / suction element ( 20 ), in particular a suction box ( 20.1 ) is arranged. Twin wire former ( 1 ) according to claim 1, characterized in that preferably not directly through the roll shell ( 18.M ) suctioned guide roller ( 18 ) a grooved, blind drilled, drilled or otherwise structured surface structure ( 18.S ) having. Twin wire former ( 1 ) according to claim 2, characterized in that the guide roller ( 18 ), in particular the surface structure ( 18.S ) of the guide roller ( 18 ) an open area ( 18.F ) of ≥ 20%, preferably ≥ 30%, in particular ≥ 40%. Twin wire former ( 1 ) according to claim 1, 2 or 3, characterized in that the forming element ( 6 ) a forming roll ( 6.1 ) with a roll diameter ( 6.1d ) in the range of 1,000 to 2,500 mm, preferably of 1,500 to 2,000 mm, in particular of 1,700 to 1,900 mm, and that the two sieves ( 4 . 5 ) with the at least one fibrous suspension between them ( 3 ) in one of the forming roll ( 6.1 ) in Sieblaufrichtung (S) downstream region of the twin-wire zone ( 12 ) at an angle (A) of 10 to 50 °, preferably from 20 to 40 °, in particular from 25 to 35 °, to an imaginary vertical plane (V) run down. Twin wire former ( 1 ) according to one of the preceding claims, characterized in that between that in the wire loop of the second wire ( 5 ) arranged Formiersaugkasten ( 13 ) and in the sieve loop of the first sieve ( 4 ) arranged separating device ( 17 ), preferably the curved and evacuated separating element ( 17.1 ), in particular the roller or the stationary vacuum cleaner, a deflection device ( 21 ), preferably a deflecting element ( 21.1 ), in particular a deflection roller, in the screen loop of the second screen ( 5 ), the two screens ( 4 . 5 ) with the at least one fibrous suspension between them ( 3 ) after the deflection device ( 21 ), preferably the deflecting element ( 21.1 ), in particular the guide roller, at an angle, preferably at an angle (B) of> 0 to 45 °, in particular at an angle of 5 to 25 °, to an imaginary horizontal plane (H) upwards. Twin wire former ( 1 ) according to claim 1, characterized in that the forming element ( 6 ) a rigid, curved and suctioned impingement shoe ( 6.2 ) with a shoe length ( 6.2L ) from 200 to 2,000 mm, preferably from 300 to 1,500 mm, in particular from 400 to 1,200 mm, and that the two sieves ( 4 . 5 ) with the at least one fibrous suspension between them ( 3 ) in a region of the twin-wire zone arranged downstream of the impingement shoe in the direction of machine direction (S) ( 12 ) at an angle (D) of> 0 to 45 °, preferably from 5 to 25 °, to an imaginary horizontal plane (H) upwards. Twin wire former ( 1 ) according to any one of the preceding claims, characterized in that in the at least one forming zone ( 15 ), opposite the forming suction box ( 13 ) and in the wire direction (S) at a distance (C) to the leading edge of the first rigid strip ( 14 ) of the Formiersaugkastens ( 13 ) at least two between each two adjacent and rigid strips ( 14 ) of the Formiersaugkastens ( 13 ) arranged formation bars ( 22 ) provided by means of compliant elements ( 23 ) are supported and with a selectable force ( 23.K ) against the first sieve touching it ( 4 ) are pressed. Twin wire former ( 1 ) according to any one of the preceding claims, characterized in that in the at least one forming zone ( 15 ), opposite the forming suction box ( 13 ) and in the wire direction (S) at a distance (C) to the leading edge of the first rigid strip ( 14 ) of the Formiersaugkastens ( 13 ) at least one deflector ( 24 ) is provided. Twin wire former ( 1 ) according to one of the preceding claims, characterized in that the rolls (W) are designed such that the sum of all roll deflections in the web or machine center of the rolls (W), resulting from a total load, in particular a total operating load, including inter alia the screen tension and the dead weight, ≤ 10 mm, preferably ≤ 7 mm, in particular ≤ 5 mm, is. Twin wire former ( 1 ) according to one of the preceding claims, characterized in that the ratio of the difference of the length of a respective wire loop from edge to center based on the total length of this wire loop ≤ 5%, preferably ≤ 4%, in particular ≤ 3%. Machine ( 100 ) for producing a fibrous web ( 2 ), in particular a paper, board or packaging paper web of at least one pulp suspension ( 3 ), characterized in that it comprises at least one twin-wire former ( 1 ) according to one of the preceding claims. Machine ( 100 ) according to claim 11, characterized in that the twin-wire former ( 1 ) is arranged downstream of a press section with at least one press unit, in particular a shoe press, preferably directly in the machine or wire direction (S).

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