DE10242564A1 - Papermaking process has two de-watering sieve belts running back-to-back and tangentially deflected at the mid-point by a transverse wiper blade - Google Patents

Abstract

In a papermaking process a fibrous suspension is sandwiched between outer (5) and inner (4) moving de-watering sieve belts (4, 5), as they progress back-to back from a first drum (13) to a second forming drum (7). At a point approx. mid-way between the two drums, the belts are tangentially deflected towards the inner belt (4). The tangential deflection is effected by a wiper blade (16). Also claimed is a commensurate papermaking process

Description

The invention relates to a method for the production of a fibrous web, in particular a paper or cardboard web, from at least one fiber suspension, with two revolving endless sieves (inner sieve, outer sieve), the inner sieve over one Circumferential area of a forming roller is guided and the outer wire over a Circumferential area of a breast roller is guided and then in the area the forming roller on the inner wire to form a wedge-shaped stock inlet gap, a pulp suspension directly from a headbox records, led and then one Double sieve section through the two sieves (inner sieve, outer sieve) is formed, which after expiration of the forming roll under a Angles from –50 ° to + 50 ° to one imaginary vertical plane runs down and at the end one Deflection device, in particular a deflection roller is arranged by means of which the two screens preferably in one essentially horizontal running direction can be redirected.

The invention further relates to a twin wire former of a machine for producing a fibrous web, in particular a paper or cardboard web, according to the preamble of the claim 4th

Such a twin wire former is for example from the German published application DE 198 03 591 A1 (PB10656 DE) of the applicant. The twin wire former shown comprises two circulating endless screens (inner wire, outer wire), of which the inner wire runs over a circumferential area of a forming roll and the outer wire runs over a circumferential area of a breast roll and then in the area of the forming roll onto the inner wire to form a wedge-shaped stock inlet gap which immediately absorbs a pulp suspension from a headbox. The two sieves (inner sieve, outer sieve) then form a twin-wire section, which runs downward from the forming roller at an angle of -50 ° to + 50 ° to an imaginary vertical plane and at the end of which a deflection device, in particular a deflection roller, is arranged , which deflects the two screens in a preferably substantially horizontal direction. In the area of the downward-running twin-wire section, a plurality of dewatering elements in the form of a forming shoe are arranged on both sides, which act on the fibrous web lying and forming between the two screens. After the deflection and at the end of the twin-wire section, the two screens run over a separating device which separates the outer wire from the fibrous web formed and the inner wire.

This well-known twin wire former has the disadvantage that the formation shoe in overload operation most diverse defects within the fibrous web to be formed can cause. moreover this configuration of the twin wire former causes increased screen wear in the area of the drainage elements.

So-called roll formers are also known, such as an embodiment in the German published application DE 44 43 874 A1 (PB10112 DE) of the applicant. In this case, two continuous endless screens are provided, which converge along a forming cylinder to form a material inlet gap, over the circumference of which the two endless screens are at least partially guided together, one of the screens being a transport screen and the other being a counter screen. Furthermore, a second forming cylinder arranged in the other sieve is provided behind the first forming cylinder arranged in one of the sieves in the direction of the wire running, with this second forming cylinder being followed by a further fixed dewatering device with a subsequent separating device in the direction of the wire running.

A disadvantage of this roll former is that the adhesion between the two sieves is low and thus allows a slip between the two sieves, even favored becomes. As a result, you can again various defects within those to be formed Fiber web arise. Furthermore, such a roll former is characterized by a relatively low drainage performance characterized.

It is therefore an object of the invention a method and a twin wire former of the aforementioned Kind to improve in such a way that both a lower sieve wear compared to twin sieve formers with formation shoes or a higher adhesion between the two screens as well as improved drainage performance compared to twin wire formers without forming shoes (roll formers).

This task is done in a process of the type mentioned in the invention solved in that the two screens between the forming roller and the deflection device by means of at least one machine-wide stripping device from one between the forming roller and the deflection device Tangent to be deflected towards the inner screen.

The object of the invention is based on completely solved this way.

This immersion of the machine-wide stripping device creates a pressure peak at its inlet, which prevents the occurrence of the so-called “water ski effect”. The stripping device holds the pressure peak even when the inlet conditions of the fibrous web change, as in the case of for example the suspension height, constant. This ensures an optimal frictional connection between the two screens with the best possible avoidance of differential speeds. In addition, screen wear and the energy requirement of the twin wire former are noticeably reduced, and a compact design of the same is also created.

In a further embodiment of the invention it is envisaged that the two screens in the range from 0 mm to 10 mm, preferably from 1 mm to 7 mm, deflected from the imaginary tangent and / or that the two screens are at a distance from the end Tangent point of the forming roller in the range from 25 mm to 300 mm, preferably from 50 mm to 200 mm. These geometries according to the invention favor in a positive way a lower sieve wear, a higher adhesion between the two screens and improved drainage performance of the twin wire former.

The object of the invention is in a twin wire former of the type mentioned in that at least one machine width Scraper device, in particular a machine-wide scraper bar, is arranged between the forming roller and the deflection device in such a way that they're in the outside strainer immersed and that the two sieves were separated from one the forming roller and the deflection imaginary tangent in Deflects towards the inner sieve.

The object of the invention will also completely solved in this way, whereby the advantages already mentioned arise.

In a further embodiment it is provided that the stripping device a depth of immersion in the outer screen in the range from 0 mm to 10 mm, preferably from 1 mm to 7 mm, since this results in the "water skiing effect" already mentioned when the further benefits mentioned entirely is avoided.

From a geometric and technological point of view, such as the avoidance of sieve tubes or more gentle Formation improvement, it is advantageous if the scraper a distance from the traversing tangent point of the forming roller in Range from 25 mm to 300 mm, preferably from 50 mm to 200 mm, having. At this distance it is guaranteed that the one to be formed Fibrous web already has a certain strength.

For possible damage largely on the fibrous web to be formed as a result of spray water flows to avoid, the scraper device with a collecting device, especially a drip pan, for collecting and draining of the dewatered by the stripping device from the fiber suspension Provided white water.

It is also provided that the Scraper device at least one closed, preferably extending into the area of the forming roller jet channel having. This jet channel is preferably under vacuum and / or with overpressure acted upon, in the region of the forming roller by means of at least a scraper and laterally by means of at least one gap seal is sealed. This "closed" beam channel with Vacuum and / or overpressure enables one targeted control / regulation of the drainage pressure. By negative pressure can the Reduction of drainage pressure by great Compensate roller diameter to a limited extent. By lower pressure between the filter cake can be kept open to the sieves (avoidance of "sheet sealing") and the drainage capacity increased become.

The stripping device comprises in preferably a machine-wide squeegee, one for strength reasons Last width in the range from 10 mm to 200 mm, preferably from 15 mm to 150 mm. Such a squeegee draws themselves through flexible applicability and lower costs.

In a further embodiment, the Squeegee an inlet radius in the range of 0 mm to 100 mm, an arc length in the range from 3 mm to 15 mm and an outlet radius in the range from 2 m to 5 m. These geometries ensure a defined sieve guidance in the following groin area, so that a drainage pressure ~ T / r arises. This also prevents the formation of a water film between the squeegee and effectively counteracted the sieve.

It is also advantageous if the Squeegee a tip angle in the range of 15 ° to 45 °, preferably from 25 ° to 35 °, one Outlet angle in the range from 2 ° to 45 °, preferably from 5 ° to 25 °, and a tip chamfer or tip radius in the range of 0.5 mm to 5 mm, preferably from 1 mm to 2 mm. When immersing the Squeegees without tip radius occur when wrapping around the outlet side additional Shear forces on, that can lead to defects within the fibrous web to be formed. Or but there is a so-called "foil effect" due to an undefined screen guide on the outlet side, caused by screen separations in the twin-wire area can damage the fiber structure.

Furthermore, such an execution of the Point angle a clean flow of the White water, with flow impulses especially at machine speeds of> 1,000 m / min in the cross machine direction (CD direction) can be prevented. This in turn leads to make the White water drainage, which moreover the moisture and basis weight cross profiles improve.

In order to be able to adjust, regulate or control the intensity of the stripping, it is provided that that the stripping device, in particular the stripping strip, can be pressed elastically onto the outer screen. The pressing is preferably carried out by means of at least one actuating unit, for example in the form of a cylinder, a spring element or a motor.

In a further embodiment, it is proposed that at least two stripping devices are provided, wherein at least one stripping device is immersed in each of the outer sieve and the inner sieve. This configuration favors considerably less wear and tear on the screen, a higher adhesion between the two screens and improved drainage performance of the twin wire former.

It is also advantageous in terms of constructive and economic aspects when the twin-wire section has a forming roll, which according to the invention advantageously has a Diameters in the range from 1.0 m to 3.0 m, preferably from 1.2 m to 2.4 m, and has a wrap angle in the range of 10 ° to 180 °. This forming roller is ideally designed as an open roller and unlocked by means of a grill or honeycomb structure and / or it is a suction roll.

The deflector of the twin wire former is preferably designed as a deflection roller and has a diameter in the range from 0.4 m to 2.4 m, preferably from 1.0 m to 1.8 m, and a wrap angle in the range from 50 ° to 180 °. The deflection device is cheaper Way as a deflecting roller in the form of a buckling roller or forming roller educated.

The longitudinal axes also point the forming roller and the deflection device preferably a horizontal one Distance on that in the range of +1.25 * diameter of the forming roller (in the direction of travel) to –1.25 * The diameter of the forming roller (opposite to the running direction) is. This length is particularly advantageous for conversions, as this is usually the case only a limited space is available.

Other features and advantages of Invention result from the dependent claims and the following Description of preferred embodiments with reference to the drawing.

Show it

1 : a schematic side view of a twin wire former according to the invention;

1A : a schematic side view of a stripping device of the twin wire former according to the invention;

1B and 1C : two schematic and detailed side views of stripping devices of the twin wire former according to the invention;

2 : Another schematic and detailed side view of a stripping device of the twin wire former according to the invention;

2A and 2 B : two detailed views of the squeegee of the 2 ; and

3 : Another schematic side view of the twin wire former according to the invention.

The 1 shows a schematic side view of a twin wire former 1 a machine for producing a fibrous web 2 , in particular a paper or cardboard web, from at least one fiber suspension 3 , with two revolving endless sieves (inner sieve 4 , Outer sieve 5 ), of which the inner sieve 4 over a circumferential area 6 a preferably vacuumed forming roller 7 runs and the outer screen 5 over a circumferential area 8th a breast roller 9 runs and then in the area of the forming roller 7 on the inner sieve 4 to form a wedge-shaped stock entry gap 10 which is directly from a preferably dilution water-regulated headbox 11 a fiber suspension 3 picks up, runs up and the two sieves (inner sieve 4 , Outer sieve 5 ) then a twin wire section 12 form that after expiration of the forming roller 7 at an angle δ of -50 ° to + 50 ° (schematic range indication - / + δ) down to an imaginary vertical plane V and at the end of a deflection device 13 , in particular a deflection roller 13.1 is arranged, the two sieves 4 . 5 deflected in a preferably substantially horizontal running direction L (arrow). After the redirection and at the end of the twin wire section 12 the two sieves run 4 . 5 via a separator 14 that the outer screen 5 from the fibrous web formed 2 and the inner sieve 4 separates. The outer screen 5 runs over guide rollers 15 back to the breast roller 9 , whereas the inner sieve 4 with the fibrous web lying on it 2 is guided to a pick-up roller, not shown, before it is also guided over guide rollers 15 back to the forming roller 7 running.

The twin wire former shown here 1 according to the execution of the aforementioned German published application DE 198 03 591 A1 (PB10656 DE) of the applicant can in a further embodiment also in accordance with the execution of the German published application DE 196 51 493 A1 (PB10449 DE) of the applicant. In other words, the possible design of the twin wire former should not be based on the design according to 1 be limited to the execution according to the 1 should only have exemplary character for a large number of possible design variants for the twin-wire former.

It is now provided that at least one machine-wide stripping device 16 , especially a machine-wide squeegee 16.1 , between the forming roller 7 and the deflection device 13 is arranged so that it is in the outer sieve 5 immersed and that while doing so the two sieves 4 . 5 from one between the forming roller 7 and the deflection device 13 imaginary tangent T (str smiled representation) towards the inner sieve 4 distracting.

The scraper 16 has an immersion depth t in the outer screen 5 in the range from 0 mm to 10 mm, preferably from 1 mm to 7 mm, and a distance a from the running tangent point TP of the forming roll 7 in the range from 25 mm to 300 mm, preferably from 50 mm to 200 mm.

The stripping device further comprises 16 a machine-wide squeegee 16.1 , which ideally has a last width B in the range from 10 mm to 200 mm, preferably from 15 mm to 150 mm.

Moreover, the scraper 16 with a fall arrester 17 , especially a drip pan 17.1 , for collecting and deriving the by the stripping device 16 from the fiber suspension 3 dewatered white water 18 Mistake. The fall arrest facility 17 can be made closed in a further embodiment and be provided with at least one preferably suctioned outlet.

The forming roller 7 of the twin wire former 1 has a diameter D _F in the range from 1.0 m to 3.0 m, preferably from 1.2 m to 2.4 m, and a wrap angle ε _F in the range from 10 ° to 180 °.

The deflection device 13 of the twin wire former 1 however, is as a deflection roller 13.1 formed and has a diameter D _U in the range from 0.4 m to 2.4 m, preferably from 1.0 m to 1.8 m, and a wrap angle ε _V in the range from 50 ° to 180 °. The deflection device 13 is as a deflection roller 13.1 formed in the preferred form of an articulated roller or forming roller.

The 1A shows a schematic side view of a stripping device 16 of the twin wire former according to the invention 1 ,

It is provided that the stripping device 16 at least one closed, preferably down to the area of the forming roller 7 extending beam channel 19 having. The beam channel 19 can be acted upon by means of a vacuum device (arrow), not shown, but known and preferably controllable / regulatable, with vacuum (−p) and / or with overpressure (+ p), in the region of the forming roller 7 by means of at least one known scraper 20 and laterally by means of at least one known gap seal 21 is sealed. The scraper 16 is of course again with a fall arrester 17 for collecting and draining through the stripping device 16 from the fiber suspension 3 dewatered white water 18 Mistake.

The two 1B and 1C show two schematic and detailed side views of as squeegees 1.6 trained wipers 16 of the twin wire former according to the invention 1 ,

The two squeegees have 16.1 each have an outlet angle α in the range from 2 ° to 45 °, preferably from 5 ° to 25 °. In addition, the squeegees 16.1 with different, the outer sieve 5 touching contours, such as zigzag or sawtooth or wave-like shape.

As part of the optional setting, regulation or control of the intensity of the stripping, it is provided that the stripping device 16 , especially the squeegee 16.1 , elastic to the outer sieve ( 5 ) can be pressed. The pressure (directional arrow E) is preferably carried out by means of at least one actuating unit which is not explicitly shown but is known to the person skilled in the art, for example in the form of a cylinder, a spring element or a motor. Of course, in a further version, several can also be used via the outer screen 5 sectionally distributed actuating units with possibly different settings can be provided.

The 2 shows a further schematic and detailed side view of a stripping device 16 of the twin wire former according to the invention 1 ,

The scraper 16 is like a squeegee 16.1 formed, which has an inlet radius R, in the range from 0 mm to 100 mm, an arc length L _B in the range from 3 mm to 15 mm and an outlet radius R ₂ in the range from 2 m to 5 m. And again it's on the squeegee 16.1 formed outlet angle α in the range from 2 ° to 45 °, preferably from 5 ° to 25 °, recognizable.

The two 2A and 2 B show two detailed views of the squeegee 16.1 the 2 ,

It can be seen that the squeegee 16.1 has a tip angle β in the range from 15 ° to 45 °, preferably from 25 ° to 35 °, and a tip radius R ₃ in the range from 0.5 mm to 5 mm, preferably from 1 mm to 2 mm. In a further embodiment, the squeegee 16.1 also have a tip chamfer, not shown, preferably with a flat surface.

The 3 shows a further schematic side view of the twin wire former according to the invention 1 , which is in principle the embodiment of 1 equivalent. Thus, in this regard, the description of the 1 directed. It is now provided that at least two stripping devices 16 . 16A are provided, at least one stripping device each 16 . 16A in the outer sieve 5 and into the inner sieve 4 dips. In the illustrated version of the 3 are a total of two scraper devices 16 . 16A intended. Furthermore, the longitudinal axes I, II of the forming roller 7 and the deflection device 13 a horizontal distance C in the range of +1.25 * diameter D _{F of} the forming roll 7 (in the running direction L (arrow) - solid representation) up to –1.25 * diameter D _{F of} the forming roller 7 (opposite to the running direction L (arrow) - dashed line).

With the twin wire former according to the invention 1 can also the inventive method for producing a fibrous web 2 be performed.

The two sieves 4 . 5 are between the forming roller 7 and the deflection device 13 by means of at least one machine-wide stripping device 16 from one between the forming roller 7 and the deflection device 13 imaginary tangent T towards the inner sieve 4 distracted. The two sieves 4 . 5 preferably in the range from 0 mm to 10 mm, in particular from 1 mm to 7 mm, from the imaginary tangent T and at a distance from the traversing tangent point TP of the forming roll 7 in the range from 25 mm to 300 mm, preferably from 50 mm to 200 mm.

In summary it should be noted that by the invention a method and a twin wire former of the type mentioned at the outset with both lower screen wear compared to twin-wire formers with formation shoes or a higher adhesion between the two screens as well as improved drainage performance across from Twin wire formers without forming shoes (roll formers) is created.

1

twin

2

Fibrous web

3

Fibrous suspension

4

inside screen

5

outer wire

6

peripheral region (Forming roll)

7

forming roll

8th

peripheral region (Breast roll)

9

breast roll

9.1

Brustformierwalze

9.2

Open surface

10

Stock inlet gap

11

headbox

12

twin-wire

13

deflecting

13.1

deflecting

14

separator

15

guide roll

16 16A

stripping

16.1

squeegee

17

catcher

17.1

drip tray

18

white water

19

beam channel

20

scraper

21

gap seals

a

distance

B

last width

c

distance

D _F

diameter (Forming roll)

D _U

diameter (Deflection)

e

Pressure (direction arrow)

I

longitudinal axis (forming roll

II

longitudinal axis (Deflection)

L

direction (Arrow)

L _B

arc length

+ p

overprint

-p

vacuum

R ₁

entry radius

R ₂

outlet radius

R ₃

tip radius

t

Immersion depth

T

tangent

TP

tangent point

V

vertical plane

α

exit angle

β

Point angle

δ

angle

ε _F

Wrap angle (Forming roll)

ε _U

Wrap angle (Deflection)

Claims (21)

Process for producing a fibrous web ( 2 ), in particular a paper or cardboard web, from at least one fiber suspension ( 3 ), with two continuous sieves (inner sieve ( 4 ), Outer sieve ( 5 )), the inner sieve ( 4 ) over a circumferential area ( 6 ) a forming roller ( 7 ) and the outer sieve ( 5 ) over a circumferential area ( 8th ) a breast roller ( 9 ) and then in the area of the forming roller ( 7 ) on the inner sieve ( 4 ) with the formation of a wedge-shaped material inlet gap ( 10 ) directly from a headbox ( 11 ) a fiber suspension ( 3 ) picks up, is guided and then a twin wire section ( 12 ) through the two sieves (inner sieve ( 4 ), Outer sieve ( 5 )) which is formed after the formation roller ( 7 ) runs downwards at an angle (δ) of –50 ° to + 50 ° to an imaginary vertical plane (V) and at the end a deflection device ( 13 ), in particular a deflection roller ( 13.1 ) is arranged, by means of which the two sieves ( 4 . 5 ) are deflected in a preferably essentially horizontal running direction (L), characterized in that the two screens ( 4 . 5 ) between the forming roller ( 7 ) and the deflection device ( 13 ) by means of at least one machine-wide stripping device ( 16 ) from between the forming roller ( 7 ) and the deflecting direction ( 13 ) imaginary tangent (T) towards the inner sieve ( 4 ) to get distracted. A method according to claim 1, characterized in that the two screens ( 4 . 5 ) in the range from 0 mm to 10 mm, preferably from 1 mm to 7 mm, from the imaginary tangent (T). Twin wire former ( 1 ) according to claim 1 or 2, characterized in that the two screens ( 4 . 5 ) at a distance (a) from the traversing tangent point (TP) of the forming roller ( 7 ) in the range from 25 mm to 300 mm, preferably from 50 mm to 200 mm. Twin wire former ( 1 ) a machine for producing a fibrous web ( 2 ), in particular a paper or cardboard web, from at least one fiber suspension ( 3 ), with two continuous sieves (inner sieve ( 4 ), Outer sieve ( 5 )), of which the inner sieve ( 4 ) over a circumferential area ( 6 ) a forming roller ( 7 ) runs and the outer sieve ( 5 ) over a circumferential area ( 8th ) a breast roller ( 9 ) runs and then in the area of the forming roller ( 7 ) on the inner sieve ( 4 ) with the formation of a wedge-shaped material inlet gap ( 10 ) directly from a headbox ( 11 ) a fiber suspension ( 3 ) picks up, runs up and the two sieves (inner sieve ( 4 ), Outer sieve ( 5 )) then a twin wire section ( 12 ), which after the formation roller ( 7 ) runs downwards at an angle (δ) of –50 ° to + 50 ° to an imaginary vertical plane (V) and at the end a deflection device ( 13 ), in particular a deflection roller ( 13.1 ) is arranged, which the two sieves ( 4 . 5 ) deflected in a preferably essentially horizontal running direction (L), characterized in that at least one machine-wide stripping device ( 16 ), especially a machine-wide squeegee ( 16.1 ), between the forming roller ( 7 ) and the deflection device ( 13 ) is arranged in such a way that it 5 ) and that the two sieves ( 4 . 5 ) from between the forming roller ( 7 ) and the deflection device ( 13 ) imaginary tangent (T) towards the inner sieve ( 4 ) distracts. Twin wire former ( 1 ) according to claim 4, characterized in that the stripping device ( 16 ) a depth of immersion (t) in the outer screen ( 5 ) in the range from 0 mm to 10 mm, preferably from 1 mm to 7 mm. Twin wire former ( 1 ) according to claim 4 or 5, characterized in that the stripping device ( 16 ) a distance (a) from the trailing tangent point of the forming roller ( 7 ) in the range from 25 mm to 300 mm, preferably from 50 mm to 200 mm. Twin wire former ( 1 ) according to one of claims 4 to 6, characterized in that the stripping device ( 16 ) with a collecting device ( 17 ), especially a drip pan ( 17.1 ), for collecting and discharging through the stripping device ( 16 ) from the fiber suspension ( 3 ) drained white water ( 18 ) is provided. Twin wire former ( 1 ) according to one of claims 4 to 7, characterized in that the stripping device ( 17 ) at least one closed, preferably down to the area of the forming roller ( 7 ) extending beam channel ( 19 ) having. Twin wire former ( 1 ) according to claim 8, characterized in that the beam channel ( 19 ) with negative pressure (–p) and / or with positive pressure (+ p), in the area of the forming roller ( 7 ) using at least one scraper ( 20 ) and laterally with at least one gap seal ( 21 ) is sealed. Twin wire former ( 1 ) according to one of claims 4 to 9, characterized in that the stripping device ( 16 ) a machine-wide squeegee ( 16.1 ) which has a last width (B) in the range from 10 mm to 200 mm, preferably from 15 mm to 150 mm. Twin wire former ( 1 ) according to claim 10, characterized in that the squeegee ( 16.1 ) has an inlet radius (R,) in the range from 0 mm to 100 mm, an arc length (L _B ) in the range from 3 mm to 15 mm and an outlet radius (R ₂ ) in the range from 2 m to 5 m. Twin wire former ( 1 ) according to claim 10 or 11, characterized in that the squeegee ( 16.1 ) a tip angle (β) in the range from 15 ° to 45 °, preferably from 25 ° to 35 °, and a tip chamfer or a tip radius (R ₃ ) in the range from 0.5 mm to 5 mm, preferably from 1 mm to 2 mm. Twin wire former ( 1 ) according to one of claims 4 to 12, characterized in that the squeegee ( 16.1 ) has an outlet angle (α) in the range from 2 ° to 45 °, preferably from 5 ° to 25 °. Twin wire former ( 1 ) according to one of claims 4 to 13, characterized in that the stripping device ( 16 ), especially the squeegee ( 16.1 ), elastic to the outer sieve ( 5 ) can be pressed. Twin wire former ( 1 ) according to one of claims 4 to 14, characterized in that at least two stripping devices ( 16 . 16A ) are provided, with at least one stripping device ( 16 . 16A ) in the outer sieve ( 5 ) and into the inner sieve ( 4 ) immersed. Twin wire former ( 1 ) according to one of claims 4 to 15, characterized in that the forming roller ( 7 ) of the twin wire former ( 1 ) has a diameter (D _F ) in the range from 1.0 m to 3.0 m, preferably from 1.2 m to 2.4 m. Twin wire former ( 1 ) according to any one of claims 4 to 16, characterized in that the Forming roller ( 7 ) of the twin wire former ( 1 ) has a wrap angle (ε _F ) in the range from 10 ° to 180 °. Twin wire former ( 1 ) according to one of claims 4 to 17, characterized in that the deflection device ( 13 ) of the twin wire former ( 1 ) as deflection roller ( 13.1 ) is formed and has a diameter (D _U ) in the range from 0.4 m to 2.4 m, preferably from 1.0 m to 1.8 m. Twin wire former ( 1 ) according to one of claims 4 to 18, characterized in that the deflection device ( 13 ) of the twin wire former ( 1 ) has a wrap angle (ε _U ) in the range from 50 ° to 180 °. Twin wire former ( 1 ) according to one of claims 4 to 19, characterized in that the deflection device ( 13 ) as a deflection roller ( 13.1 ) is designed in the form of an articulated roller or forming roller. Twin wire former ( 1 ) according to one of claims 4 to 20, characterized in that the longitudinal axes of the forming roller ( 7 ) and the deflection device ( 13 ) have a horizontal distance (c) which is in the range of +1.25 diameter (D _F ) of the forming roller ( 7 ) (in the running direction (L)) to –1.25 diameter (D _F ) of the forming roller ( 7 ) (opposite to the running direction (L)).