EP1365067A1 - Forming section - Google Patents

Abstract

A multi-layered paper making machine (1) discharges suspended fibres from two or more outlets. One of the fibre suspension outlets (14, 22) has a jet chamber (14.1, 22.2) incorporating lamella (14.2, 22.2). One of the fibre suspensions (14.3, 22.3) is surrendered to the outlet (14, 22) at a density (c) in the range 0.2 per cent to 1.1 per cent with a incorporating filling material content (f) in the range 0 per cent to 80 per cent. The assembly (1) forms a paper or carton web with a number of layers, each discharged individually from an outlet (14, 22) receiving a supply of fibre suspension (14.3, 22.3). The outlets each incorporate a primary longitudinal sieve (10) and two secondary twin sieves (D) (lower sieve 16, upper sieve 18). The sieves discharge a first paper or carton layer onto a second layer as this is discharged from the primary longitudinal sieve (10). The twin-sieve formers (D) have a formation roller (24) which operates as a reversing roller for the secondary sieves (16, 18). In the direction of motion (C) a batten former (L) is positioned within the lower sieve (16) before the formation roller (24). A suction box (D) (36) is located in the upper sieve (18) in the vicinity of the upper sieve (18).

Description

The invention relates to a sheet forming device for producing a multilayer Paper or cardboard web from several fed by means of headboxes Fibrous material suspensions, consisting of a primary longitudinal screen and two as twin wire formers trained secondary sieves, the first layer of the multilayer Place the paper or cardboard web on a second layer of the primary longitudinal screen, wherein the twin wire former has a forming roller as a deflection roller for the Has course of the secondary screens, wherein in the direction of the twin wire former in front of the forming roller, a last former is arranged in the lower wire and a Suction box ("D-part") is arranged in the area of the last in the top wire.

Such a sheet-forming device is described in German Offenlegungsschrift DE 40 31 038 A1 (PB06624 DE). The device for producing a multi-layer paper or cardboard comprises a primary longitudinal screen and a secondary longitudinal screen arranged above it in the form of a twin wire former, which places an upper layer of the multi-layer paper or cardboard on a lower layer, the twin wire former having a forming roller as a deflection roller for the course of the twin wire , A pressure bar former is arranged in the direction of travel of the twin wire in front of the forming roller and the so-called water line of the fiber suspension lies in the area of the forming roller.
A disadvantage of this disclosed device is that the twin-wire former designed as a secondary longitudinal wire both creates an insufficient formation and only removes a limited amount of water with the result of poor strength. In addition, particularly due to the last, at higher speeds, such as speeds> 600 m / min, the fine particles contained in the fiber suspension are washed out.

In practice, attempts have already been made to design the secondary longitudinal sieve Twin wire former as close as possible to the associated headbox or to be placed as close as possible to the press section. The first placement owns the advantage of an improved formation, but the disadvantage of a limited one Removal of water quantity (poorer strength). The second placement on the other hand has the advantage of producing a low tear length ratio L / Q, but the disadvantage of a less than optimal formation. As result These attempts can be generally accepted that the possible placements bring respective advantages with them, but they do not realize them at the same time leave, which in turn results in the receipt of disadvantages.

It is therefore an object of the invention to provide a sheet forming device of the type mentioned To create a way with which a very good formation when removing an elevated Amount of water with the result of good strength is achieved. Farther should the individual screen lengths and the overall length of this paper or Cardboard machine section can be reduced.

According to the invention, this object is achieved in a device of the aforementioned type in that at least one headbox with a nozzle space, in which lamellae are arranged, is provided and that at least one fiber stock suspension fed to at least one headbox has a stock density in the range from 0.2% to 1. 1% and has a filler content in the range from 0% to 80%.
The arrangement of lamellae in the nozzle area of at least one headbox markedly improves the formation of the layer to be produced and, given the material density, ensures that such high turbulence is maintained down to the corresponding sieve, so that refloculation of the fiber suspension is largely avoided.

This sheet forming device according to the invention is particularly suitable for Manufacture of testliner or linerboard.

So that the fiber suspension jet is targeted and bundled onto the sieve a beam thickness in the range of 5 mm to 35 mm can be applied the headbox has a gap width in the range of 6 mm to 40 mm.

In three preferred embodiments of the invention it is provided that the slats end before the end of the nozzle, in particular in the range from 10 mm to 100 mm before the end of the nozzle, and / or that the fins in the area of the end of the nozzle ends and / or that the fins protrude beyond the nozzle end. All three embodiments favor the preservation of the high turbulence mentioned at a relatively low cost.

With regard to the removal of a sufficient amount of water from the layer to be produced, it is advantageous for the strip former arranged in the lower sieve to have between 1 and 4 pressure strips, which are preferably at least partially elastically supported. Due to the elastic support of the pressure bars, the drainage pressure can be easily adapted to different operating parameters.
From the above-mentioned aspect, it is also advantageous that the suction box arranged in the top wire ("D-part") has a maximum box length of 1200 mm and / or that the forming roller of the twin wire former has a diameter in the range from 0.5 m to 1.7 m, preferably from 0.9 m to 1.4 m, and / or that the bottom wire of the twin wire former has a pre-dewatering section whose length assumes a value in the range from 1 m to 12 m, preferably from 3 m to 10 m.
In an embodiment according to the invention, it is therefore provided that the dewatering in the twin-wire former is in the range from 15% to 60%, since among other things a very good formation is achieved with removal of an increased amount of water with the result of good strength.

It is further provided according to the invention that at least one breast roll Sheet forming device is provided with a shaking device which Breast roller with a shaking index in the range from 200 mm / (min • m) to 15,000 mm / (min • m), preferably from 1,250 mm / (min • m) to 6,000 mm / (min • m), shakes. Such shaking of the breast roller promotes in an ideal manner the aforementioned advantages according to the invention.

Furthermore, at least one headbox of the sheet forming device can also be used a sectioned substance density control (dilution water technology) his. This design of the headbox creates the possibility the throughput, the consistency and thus the basis weight and the To be able to regulate fiber orientation sectionally.

In a further special embodiment of the invention it is provided that the twin wire former is provided with a secondary headbox and the secondary headbox directed into the gusset of the converging secondary sieves is. This makes the sheet forming device for producing a multi-layer Paper or cardboard web still the possibility of multi-layer technology opened, which in turn has qualitative and technological advantages for the emerging Paper or cardboard web are created.

In a further continuation of the inventive concept, it is also proposed that the sheet forming unit of the sheet forming device has another sheet forming unit is assigned, the further sheet-forming unit being a layer the multilayer paper or cardboard web on the first, from the twin wire former of the sheet-forming unit, and the bottom wire of the twin wire former both mentioned layers on the second, from the primary longitudinal sieve Sheets the generated sheet formation layer. Through this additional sheet formation unit opens up the possibility of using a multilayer paper or cardboard web to produce more than two layers with different layer qualities.

In a further advantageous embodiment of the invention it is provided that the sheet forming unit of the sheet forming device, another sheet forming unit is assigned, the further sheet formation unit being a layer of the multilayer Paper or cardboard web on at least that of the sheet forming unit generated layers, wherein the further sheet forming unit in a further advantageous manner is designed as a primary longitudinal screen.

It goes without saying that the aforementioned and still to be explained below Features of the invention not only in the specified combination, but can also be used in other combinations or alone are without departing from the scope of the invention.

Further features and advantages of the invention emerge from the subclaims and the following description of preferred exemplary embodiments with reference to the drawing, in which the sheet forming devices according to the invention for the production of a multilayer paper or cardboard web are shown in schematic side views.

Figur 1:

eine erste erfindungsgemäße Blattbildungsvorrichtung zum Herstellen einer mehrlagigen Papier- oder Kartonbahn;

Figur 2:

eine weitere Ausführungsform einer erfindungsgemäßen Blattbildungsvorrichtung;

Figur 3:

eine Ausführungsform gemäß Figur 1 mit einem weiteren Former, wodurch ein so genannter Hybridformer entsteht;

Figur 4:

einen Doppelsiebformer gemäß Figur 2, jedoch mit einem Sekundärstoffauflauf; und

Figur 5:

eine erfindungsgemäße Blattbildungsvorrichtung mit drei Blattbildungseinheiten.

Show it

Figure 1:

a first sheet forming device according to the invention for producing a multilayer paper or cardboard web;

Figure 2:

a further embodiment of a sheet forming device according to the invention;

Figure 3:

an embodiment according to Figure 1 with a further former, whereby a so-called hybrid former is formed;

Figure 4:

a twin wire former according to Figure 2, but with a secondary headbox; and

Figure 5:

a sheet forming device according to the invention with three sheet forming units.

The figures show a sheet forming device 1 with a primary longitudinal screen 10, which moves from right to left in accordance with the running direction A (arrow) in the respective figure. In the area of a breast roll (deflection roll) 12 for the primary longitudinal screen 10 there is a headbox 14 for a lower (second) layer of the multilayer paper or cardboard web. As shown in FIG. 3, the primary longitudinal screen 10 can also be designed as a hybrid former H.
Above the primary longitudinal sieve 10 there is a twin-wire former D as a secondary sieve arrangement with a lower sieve 16 and an upper sieve 18. The sieves 16 and 18 move according to the running direction B (arrow) in the respective figure from left to right, that is to say the lower sieve 16 by one Breast roller (deflection roller) 20 in the area of a headbox 22, a forming roller 24 (here, an forming roller) with a trough 32 for removing the water and further rollers 26. The top wire 18 moves around a row of deflection rollers 28 and together with the bottom wire 16 the forming roller 24. Thus, the lower wire 16 and the upper wire 18 in front of the forming roller 24 partially move together substantially in the horizontal direction and after the forming roller (in the direction of travel C (arrow)) behind the forming roller 24 at least partially together essentially in the vertical direction. However, in an embodiment that is not shown, it is also possible for the lower wire 16 and the upper wire 18 to run downward behind the forming roller 24 at least partially together at an angle, such as, for example, at an angle of approximately 45 degrees.
In the running direction C (arrow) in front of the forming roller 24, in the region of the twin wire former D below the lower wire 16, according to the invention there is a strip former L with pressure bars 32 acting on the lower wire 16. Opposite these pressure bars 32 there is a suction box above the upper wire 18 ("D- Part ") 36.
It is now provided according to the invention that at least one headbox 14, 22 with a nozzle space 14.1, 22.1 in which fins 14.2, 22.2 are arranged is provided and that at least one fiber suspension 14.3, 22.3 fed to at least one headbox 14, 22 has a consistency c im Range from 0.2% to 1.1% and a filler content f in the range from 0% to 80% with a preferred gap width s of the headbox 14, 22 in the range from 6 mm to 40 mm and a preferred flow rate Q of fiber suspension 14.3, 22.3 in the range from 4,000 l / (m • min) to 20,000 l / (m • min). The slats 14.2, 22.2 according to the invention are only shown symbolically and they can end in front of the nozzle end, in particular in the range from 10 mm to 100 mm in front of the nozzle end, and / or they can end in the region of the nozzle end and / or they can protrude beyond the nozzle end ,
Furthermore, the strip former L arranged in the lower sieve 16 has between 1 and 4 pressure strips 32, which are preferably at least partially elastically supported, and the suction box ("D part") 36 arranged in the upper sieve 18 has a maximum box length L _S of 1,200 mm , In addition, the forming roller 24 of the twin wire former D has a diameter D _F in the range from 0.5 m to 1.7 m, preferably from 0.9 m to 1.4 m, and the lower wire 16 of the twin wire former D has a pre-dewatering section V, whose length L _{V has} a value in the range from 1 m to 12 m, preferably from 3 m to 10 m. It is envisaged that the dewatering in the twin wire former D is in the range from 15% to 60%.
In addition, at least one breast roller 12, 20 of the sheet-forming device 1 is provided with a shaking device 12.1, 20.1, which is not shown in detail but is known to the person skilled in the art and which the breast roller 12, 20 has a shaking index in the range from 200 mm / (min • m) to 15,000 mm / (min • m), preferably from 1,250 mm / (min • m) to 6,000 mm / (min • m), shakes. A shaking index in the range from 200 mm / (min • m) to 1,250 mm / (min • m) can be achieved using conventional shaking, for example in the range from 1,250 mm / (min • m) to over 5,000 mm / (min • m) ) using a DuoShake and one in the range from 4,000 mm / (min • m) to 15,000 mm / (min • m) using an electromagnetic shaker.
Furthermore, at least one headbox 14, 22 is provided in a manner not shown with a sectioned stock density control (dilution water technology), as is known, for example, from the applicant's German patent application DE 40 19 593 A1 (PA04598 DE); the disclosure content of this document is hereby made the subject of the present description.

The embodiment according to FIG. 2 differs from that according to FIG. 1 only by the other assignment of the twin wire former D to the primary longitudinal wire 10 in that the headboxes 14, 22 for the two layers on the same Side of the system are arranged. In the embodiment according to FIG 1, the material feed for the two systems takes place in opposite directions Directions or on opposite sides.

The sheet forming device 1 shown in FIG. 3 complements the sheet forming device 1 of Figure 1 in the area of the primary longitudinal screen 10 with a equipped with another former 30, whereby a so-called hybrid former H is formed becomes. The additional former 30 has both a screen 19 which is arranged around deflection rollers 27 is guided, as well as a suction box ("D-part") 36.

FIG. 4, on the other hand, shows a twin wire former D according to FIG. 2, but with a secondary headbox 23. The secondary headbox 23 is in the Gusset of the converging secondary screens 16, 18 directed.

The sheet forming device 1 shown in FIG. 5 consists of three sheet forming units 40.1, 40.2, 40.3. The middle sheet forming unit 40.1 essentially has the structure of the sheet forming device 1 according to FIG. 1; with regard to the description of the sheet formation unit 40.1, reference is therefore made to FIG. 1. The only difference of the sheet forming device 1 with respect to the embodiment according to FIG. 1 is that the lower wire 16 and the upper wire 18 behind the forming roller 24 do not run at least partially together essentially in the vertical direction, but at an angle of approximately 60 degrees downwards.
The sheet forming unit 40.1 is assigned a further sheet forming unit 40.2, the further sheet forming unit 40.2 depositing one layer (insert) of the multilayer paper or cardboard web on the first layer (insert) generated by the twin wire former D of the sheet forming unit 40.1 and the bottom wire 16 of the twin wire former D both mentioned layers (deposits) on the layer (back) generated by the primary longitudinal screen 10 of the sheet forming unit 40.1.
Furthermore, the sheet-forming unit 40.1 is assigned a further sheet-forming unit 40.3, the further sheet-forming unit 40.3 depositing a layer (blanket) of the multilayer paper or cardboard web on at least the layers (inlays and backs) generated by the sheet-forming unit 40.1. The further sheet forming unit 40.3 is designed as a primary longitudinal screen 10.1.

In summary, it should be noted that the device of the invention is created with which a very good formation when removing a large amount of water, resulting in good strength is achieved. Furthermore, the individual screen lengths and the overall length this paper or board machine section is reduced.

LIST OF REFERENCE NUMBERS

1

A forming apparatus

10,10.1

Primärlangsieb

12, 20

Breast roll (deflection roll)

12.1, 20.1

shaking

14.22

headbox

14.1,22.1

nozzle chamber

14.2, 22.2

lamella

14.3, 22.3

Fibrous suspension

16

Lower sieve (secondary sieve)

18

Upper sieve (secondary sieve)

19

scree

23

Secondary headbox

24

forming roll

26

roller

27, 28

deflecting

30

molder

32

print bar

34

tub

36

Suction box ("D-part")

40.1, 40.2, 40.3

Sheet forming unit

A, B, C

Running direction (arrow)

c

Consistency (fiber suspension)

D

twin

D _F

Diameter (forming roller)

f

Filler content (fiber suspension)

H

hybrid former

L

strip former

L _S

box length

L _V

Length (pre-drainage section)

Q

Flow rate (fiber suspension)

s

gap width

V

predrainage

Claims (17)

Sheet-forming device (1) for producing a multi-layer paper or cardboard web from a plurality of fiber suspensions (14.3, 22.3) fed by means of headboxes (14, 22), consisting of a primary longitudinal screen (10) and two secondary screens (bottom screen 16, top screen, D) 18), which place a first layer of the multilayer paper or cardboard web on a second layer of the primary longitudinal screen (10), the twin-wire former (D) having a forming roller (24) as a deflection roller for the course of the secondary screens (16, 18), whereby in the running direction (C) of the twin wire former (D) in front of the forming roller (24) a bar former (L) is arranged in the lower wire (16) and a suction box ("D part") (36) in the area of the bar former (L) in Top sieve (18) is arranged,
characterized in that at least one headbox (14, 22) with a nozzle space (14.1, 22.1), in which fins (14.2, 22.2) are arranged, is provided and
that at least one pulp suspension (14.3, 22.3) fed to at least one headbox (14, 22) has a consistency (c) in the range from 0.2% to 1.1% and a filler content (f) in the range from 0% to 80% , Sheet forming device (1) according to claim 1,
characterized in that the headbox (14, 22) has a gap width (s) in the range from 6 mm to 40 mm. Sheet forming device (1) according to claim 1 or 2,
characterized in that the fins (14.2, 22.2) end before the end of the nozzle, in particular in the range from 10 mm to 100 mm before the end of the nozzle. Sheet forming device (1) according to claim 1 or 2,
characterized in that the fins (14.2, 22.2) end in the area of the nozzle end. Sheet forming device (1) according to claim 1 or 2,
characterized in that the fins (14.2, 22.2) protrude beyond the nozzle end. Sheet forming device (1) according to one of the preceding claims,
characterized in that the strip former (L) arranged in the lower sieve (16) has between 1 and 4 pressure strips (32) which are preferably at least partially elastically supported. Sheet forming device (1) according to one of the preceding claims,
characterized in that the suction box ("D-part") (36) arranged in the upper sieve (18) has a maximum box length (L _S ) of 1,200 mm. Sheet forming device (1) according to one of the preceding claims,
characterized in that the forming roller (24) of the twin wire former (D) has a diameter (D _F ) in the range from 0.5 m to 1.7 m, preferably from 0.9 m to 1.4 m. Sheet forming device (1) according to one of the preceding claims,
characterized in that the bottom wire (16) of the twin wire former (D) has a pre-dewatering section (V), the length (L _V ) of which takes on a value in the range from 1 m to 12 m, preferably from 3 m to 10 m. Sheet forming device (1) according to one of the preceding claims,
characterized in that the dewatering in the twin wire former (D) is in the range from 15% to 60%. Sheet forming device (1) according to one of the preceding claims,
characterized in that at least one breast roller (12, 20) of the sheet-forming device (1) is provided with a shaking device (12.1, 20.1) which provides the breast roller (12, 20) with a shaking index in the range of 200 mm / (min • m) up to 15,000 mm / (min • m), preferably from 1,250 mm / (min • m) to 6,000 mm / (min • m). Sheet forming device (1) according to one of the preceding claims,
characterized in that at least one headbox (14, 22) is provided with a sectioned stock density control (dilution water technology). Sheet forming device (1) according to one of the preceding claims,
characterized in that the twin wire former (D) is provided with a secondary headbox (23). Sheet forming device (1) according to claim 13,
characterized in that the secondary stock head (23) is directed into the gusset of the converging secondary screens (16, 18). Sheet forming device (1) according to one of the preceding claims,
characterized in that the sheet forming unit (40.1) of the sheet forming device (1) is assigned a further sheet forming unit (40.2), the further sheet forming unit (40.2) a position of the multilayer paper or cardboard web on the first, from the twin wire former (D) of the sheet forming unit ( 40.1) deposits the generated layer and the bottom wire (16) of the twin wire former (D) deposits both of these layers onto the second layer generated by the primary longitudinal wire (10) of the sheet forming unit (40.1). Sheet forming device (1) according to one of the preceding claims,
characterized in that the sheet forming unit (40.1) of the sheet forming device (1) is assigned a further sheet forming unit (40.3), the further sheet forming unit (40.3) depositing a layer of the multilayer paper or cardboard web on at least the layers generated by the sheet forming unit (40.1) , Sheet forming apparatus (1) according to claim 16,
characterized in that the further sheet formation unit (40.3) is designed as a primary longitudinal screen (10.1).

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