DE10101549A1 - Production of a multi-layer paper/cardboard web, has couching station(s) along the web path where water is extracted and the fine matter is dispersed between layers to give a firm bond between them - Google Patents

Abstract

To produce a multi-layer paper or cardboard web, the fiber pulp is converted into layers at the forming stages to be couched together. In at least one couching nip, the water extraction action gives a flow of fine matter at right angles to the web plane from the zones with a high fine material content to the zones with a lower fine material content and/or from zones with a high fiber bonding to the zones with a lower fiber bonding. To give a multi-layer paper/cardboard web, the distribution of the fine matter is effected at the couching nip between a couching roller and a couching shoe roller, or between two couching shoe rollers, or between a couching roller and a press belt. A control action on the water extraction from the web, either by blocking it or increasing it, affects the direction of the dispersion of fine matter within the web layers. A water-absorbent belt is at least on one side of the web, passing through the couching nip, and at least one water-impermeable belt is on one side of the web passing through the couching nip and/or an impermeable and non-absorbent belt is on one side of the web through the couching nip. One surface of the web can be in contact with the roller at the couching nip. In the couching nip, the pressure increase phase on the web gives a pressure gradient from 5 kPa/mm to 50 kPa/mm, and is \}100 kPa/mm in the final couching nip. At the end of a couching nip, where there is a following couching nip in the web path, the outer surface of the layered web to take the next couched layer has a dry content of 7-16% and preferably 9-14% and/or at least one of the layers to be couched together has a dry content of 7-12% and preferably 8-10%. At the end of a couching nip, where there is a further couching nip in the web path, with a bonded multi-layer web weight of up to 200 g/m<2>, a linear force is applied of 1-100 kN/m and preferably 5-40 kN/m and/or 1-100 kN/m, and preferably 2-30 kN/m with a web weight over 200 g/m<2>. At the final couching nip, the linear force on a web up to 200 g/m<2> is 1-300 kN/m and preferably 5-150 kN/m and/or the linear force for a web over 200 g/m is 1-200 kN/m and preferably 2-100 kN/m. Water is extracted from one side of the web in at least one couching nip. A pressure is applied to at least one of the layers to be brought together, in front of each couching nip in the direction of web travel (L). On leaving each couching nip, the web passes around one of the two components forming the nip, to control the path of the emerging web. The fine matter and fibers in the web are activated by a steam blowing chamber in front of each couching nip. An Independent claim is included for the fourdrinier section of a papermaking/cardboard production machine, with at least one couching nip (10) to take the formed web layers (12,14). Preferred Features: The couching nip is formed between a couching roller (20) and a couching shoe (22) or shoe roller or belt.

Description

The invention relates to a method for producing a multilayer company serstoffbahn, in particular paper or cardboard web, made of a fibrous material suspension. It also relates to a wire section of a machine for the manufacture development of such a multilayer fibrous web. Such a process and such a wire section are, for example, in DE-A-196 51 493 and DE-A-199 03 943.

The Z strength of a multilayer product is largely determined by the Fine substance concentration in the bond plane (s) between the La co-determined on the paper or cardboard.

In order to achieve a high quality of a with increasing production speed to reach individual layers, twin-wire formers are increasingly being used. H. for example gap formers and hybrid formers. The thereby he enough layer quality such as improved formation and strength However, the machine's running and cross-machine direction bring about Depletion of the layer surfaces of fine materials. These fines it is now, however, that create a good bond between the layers. Also within the individual La formed on a twin wire former There are zones with few fines. So a formed at the gap former splits Leaf generally lighter than a leaf formed on the Fourdrinier wire. In which from DE-A-199 03 943 known method is the addition of Zu Substance controlled or regulated in such a way that in the Fa a certain ratio between the fine material content of the  Web top and the fine material content on the bottom of the web results. to Achievement of a corresponding fine substance content ratio in an egg nem formed double web former over the two screens one Drainage can be done with different intensities.

The aim of the invention is to provide an improved method and an improved To create screen section of the type mentioned, with which in particular re a higher Z strength of the multilayer fibrous web obtained is aimable.

According to the invention, a method for producing this object is achieved position of a multilayer fibrous web, in particular paper or Cardboard web, proposed from a fiber suspension, in which the layers formed together by a respective former be and in particular in at least one Gautschnip by one appropriate drainage and generation of at least essentially a fine material wall perpendicular to the plane of the path change or shift, distribution and / or transport of zones higher fines content to zones of lower fines content and / or from zones of higher fiber entanglement to zones of lower fiber entanglement braid is enforced.

Optimal results can be achieved in particular if the ge at least substantially perpendicular to the web or plate plane directed flow in a phase of relatively high fine matter mobility, depending sufficient fiber immobility is already being generated.  

It is particularly advantageous if the fine material migration directly in Zu in connection with the gossip. Also the pressure course there is a certain importance during the gumming up.

In order to achieve the desired fine material transport, the following pairings of opposing rubber elements are particularly advantageous:
For example, a corresponding fine material distribution can be enforced in at least one Gautschnip formed between a rubber roller and a rubber shoe, between a rubber roller and a rubber shoe roller, between two rubber shoes and / or between a rubber roller and a pressure belt.

The direction of the fine material migration can be determined in particular by a loading preventing and / or supporting the water leakage from the fiber material web are influenced accordingly.

For example, a respective gumming roller can be smooth or one Have water storage volume. Accordingly, a respective ger rubber shoe or a respective rubber roller be flat or a Have water storage volume. For example, come as a pressure tape a water-impermeable belt, for example a transfer belt or the like, or a water-permeable or water-absorbing Tape, for example a sieve or felt.

It is particularly in the case of a higher water intake in the respective digging snip also advantageous if on at least one side of the fibrous web  water-storing tape with through the respective Gautschnip becomes. A sieve, a belt, for example, can be used as the water-storing belt similar to the roller jacket of a shoe roller in a shoe press, the for example, Qualiflex® (Voith product), or the like chen, be provided. Basically, it is also possible, for example the Aufgautschwalze and / or a respective rubber shoe with vacuum to act on, for example drilled covers or ge slotted coverings can be provided.

In order to ensure that a ver Preventing the web from pressing should be kept to a minimum the hydraulic pressure acting on the web increased in machine running direction must be respected. As a result, one should at least essentially Chen flow perpendicular to the web or sheet plane be. It is thus avoided that water is inside the fiber web flows against the machine direction, which is a strong lo kale reduction in consistency and displacements would result.

Depending on the fiber material, basis weight and dry content the digested orbits should be in the area of a respective Gautschnips in the Phase of the pressure rise of the gauze or grouting concerned solution a pressure gradient of preferably about 5 kPa / mm to about 50 kPa / mm or in the area of the last Gautschnips up to about 100 kPa / mm not be exceeded.

The line force is according to the desired drainage or To choose dryness increase. For multi-layer products is on Adequate moisture content after each gossip  to ensure that the layers subsequently added are sufficient suitable bond are spoiled. The last one is an exception Gossip.

According to the invention, a method for producing a multilayer fibrous web, in particular paper or cardboard web a fiber suspension, proposed, in which the by a respective layers formed layers are gassed together, whereby in Connection to at least one previous Gautschnip, and in the An close to a Gautschnip, on which at least one other Gaut snip follows, the dry content of the already multi-layer fibrous web the side of the web on which at least one other layer is open is in a range from about 7 to about 16%, preferably in is in a range from about 9 to about 14% and / or at least one the sub-webs to be gummed together then a troc content in a range from about 7 to about 12%, preferably in egg has a range from about 8 to about 10%. That is u. a. the thought based on the fact that the total dry content of the multilayered web is higher can be, it is important that sufficient on the rubber side Moisture is present.

It is also advantageous if in a Gautschnip, which is followed by at least one further Gautschnip, with a basis weight of the already multi-layer fibrous web up to about 200 g / m ^2, a line force in a range from about 1 to about 100 kN / m, preferably in a range from about 5 to about 40 kN / m, and / or with a basis weight above about 200 g / m ² a line force in a range from about 1 to about 100 kN / m, preferably in a range from about 2 to about 30 kN / m.

With regard to the last Gautschnip, it is advantageous if, with a basis weight of the multi-layer fibrous web of up to approximately 200 g / m ^2, a line force in a range from approximately 1 to approximately 300 kN / m, preferably in a range from approximately 5 to approximately 150 kN / m, and / or at a basis weight above about 200 g / m ^2, a line force in a range from about 1 to about 200 kN / m, preferably in a range from about 2 to about 100 kN / m, is generated.

In particular, when producing a multi-layer fibrous web re can also be an advantage if at least one precedes the area the Gautschnips, d. H. following a Gautschnip, on the still at least one other Gautschnip follows, one-sided drainage is sufficient to one side of the track for further gossiping keep moist.

In individual cases, touching the webs to be rubberized can be be an advantage before the actual digging snip. In this zone then only the one resulting from, for example, a fabric tension acts Pressing, for example a pre-wrap or pre Gautscht can exist. It is therefore advantageous to run in the web direction in front of a respective Gautschnip at least one of the other pre-pressed to be rubberized.

Moreover, one of the two rubber elements can be looped of the Gautschnips concerned advantageous for controlling the further Web run can be used (glass plate effect).  

According to a further advantageous embodiment of the invention Proceedings are made in the direction of web travel before each Gautschnip the fine substances and fibers are activated by a steam blower box.

The invention provided for solving the above object Sieve section includes at least one Gautschnip, in each by layers formed layers are spilled together and by appropriate drainage and generation at least a flow directed essentially perpendicular to the path plane Fine material migration or displacement, distribution and / or transport from zones of higher fines to zones of lower fines and / or from zones of higher fiber entanglement to zones of lower company server integration is enforceable.

Advantageous embodiments of the wire section according to the invention are specified in the subclaims.

The invention is un based on exemplary embodiments ter explained in more detail with reference to the drawing; in this show:

Fig. 1 of a couch roll is a schematic representation between an on and an Gautschschuh formed Gautschnips,

Fig. 2 is a schematic representation of a couch roll between an on and an Gautschschuhwalze Gautschnips formed, wherein at least one of the layers is formed with one another to vergautschenden by a Fourdrinier former and prepressed this situation,

Fig. 3 is a schematic representation of a formed between a rubber roller and a pressure belt nips and

Fig. 4 is a schematic representation of a Gautschnips formed between two rubber shoes.

The Gautschnips 10 shown in FIGS . 1 to 4 are each provided in a wire section of a machine for producing a multilayer fibrous web, in particular paper or cardboard web. Depending on the number of layers, several such Gaut snips 10 can also be provided in the wire section.

The layers 12 , 14 formed in each case by a former and to be rubberized in the relevant Gautschnip 10 in the Gaut Schnip 10 are each fed through a circulating belt 16 or 18 .

In the respective Gautschnip is drained accordingly tion and generation of an at least substantially perpendicular to the Path or sheet-level flow a fine material migration or shifting, distributing and / or transporting zones higher Fines content to zones of lower fines content and / or from Zo higher fiber entanglement to zones of lower fiber entanglement forced.  

In the embodiment shown in Fig. 1, the Gautschnip 101 is between a Aufgautschwalze 20 and a rubber shoe 22 forms ge.

In the web running direction L behind the Gautschnip 10 ₁ , a separating suction device 24 is provided within the loop of the circulating belt 18 in order to separate the multilayered web from the circulating belt 16 and to hold it on the circulating belt 18 .

In the embodiment according to FIG. 2, the Gautschnip 10 _{2 is} between a Aufgautschwalze 20 and a Gautschschuhwalze 26 gebil det. A separating suction device 24 is again provided in the loop of the circulating belt 18 in the web running direction L behind the Gautschnip 10 ₂ .

In the present case, the layer 12 is formed by a Fourdrinier former 28 and pre-pressed before reaching the Gautschnips 10 ₂ in the region of a roller 30 by the tension of a sieve 32 guided together with the belt 16 and the layer 12 around this roller 30 .

As can be seen on the basis of FIG. 2, the resulting multilayer fibrous web with the belt 18 following the line is guided horizontally around a screen suction roller 34 .

In the embodiment shown in Fig. 3, the Gautschnip 10 _{3 is} gebil det between a Aufgautschwalze 20 and a pressure belt 36 , which is tensioned by a tensioning roller 38 and before and after the Gautschnip 10 ₃ is guided by a deflection roller 40 and 42 respectively. As can be seen from FIG. 3, there is a subsequent wrap of the pressure belt 36 assigned to the guide roller 42 through the multi-layer fibrous web and the band 18 following the Gautschnip 10 ₃ .

In the embodiment according to FIG. 4, the Gautschnip 10 _{4 is formed} between a Aufgautschschuh 44 and a Gautschschuh 22 . Following the Gautschnip 10 ₄ , a vacuum cleaner 24 is again provided within the loop of the Ban des 18 .

In the present exemplary embodiments, the higher Z strength each achieved that a fine migration of zones high Fines content in zones of low fines content and / or lower Fiber entanglement is enforced. For this purpose, in the fibrous web. H. in particular paper or cardboard web, still relatively high in one phase Fine substance mobility, but already sufficient fiber immobility flow directed at least substantially perpendicular to the plane of the sheet enforced.

The direction of the fine material migration can be influenced by hindering or supporting the water discharge from the web. For example, the gumming roller 20 can be smooth or, as indicated in FIGS . 1 to 3, have a water storage volume. Accordingly, the rubber shoe (s) 22 , 44 or the rubber shoe roller 26 can also be smooth or have a water storage volume. As the pressure belt 36 , for example, a water-impermeable belt, for example a transfer belt or the like, or a water-permeable or water-absorbing belt, for example a sieve or felt, can be considered.

In addition, in the case of particularly high water accumulation in the digging snip 10, a water-storing belt, for example a sieve, can be used on the relevant side or on both sides, a belt similar to the roller jacket of a shoe roller in a shoe press, which belt can consist, for example, of Qualiflex® (Voith product), or the like, are passed through the Gautschnip. Vacuum roller 20 and / or rubber shoe 22 or 44 can also be subjected to a vacuum, for which purpose drilled covers or slotted coverings can be provided, for example.

Depending on the basis weight and dry content of the to be gummed Paths should expediently be in the phase of pressure increase Pressure gradient from about 5 kPa / mm to about 50 kPa / mm or in the range of the last Gautschnips up to about 100 kPa / mm the.

The line force is according to the desired drainage or To choose dryness increase. For those who are primarily interested here Multilayer fibrous webs are on an adequate web to watch out for the humbling, in order for the subsequently added layers a gossip with sufficient Ensure bond. So this is about the case that still mind at least another layer is added. In this case, the already multilayered web advantageously at least essentially in range from about 7 to about 16% dryness, preferably two se in the range of about 9 to about 14%. It is also an advantage if little at least one of the two webs to be gummed has a dry content from, for example, about 7 to about 12%, preferably a dry content  from about 8 to about 10%. The last one is an exception Gossip.

The following line forces come for example for the gushing areas in question:

Previous, d. H. not last gossip

Basis weight up to 200 g / m ²

→ LK = 1 to 100 kN / m, preferably 5 to 40 kN / m
Basis weight over 200 g / m ²

→ LK = 1 to 100 kN / m, preferably 2 up to 30 kN / m

Last gossip

Basis weight up to 200 g / m ²

→ LK = 1 to 300 kN / m, preferably 5 to 150 kN / m
Basis weight over 200 g / m ²

→ LK = 1 to 200 kN / m, preferably 2 up to 100 kN / m

Is particularly advantageous in the production of multilayer products for example, one-sided drainage to one side of the web keep additional rubbers sufficiently moist.

In individual cases, touching the webs to be rubberized may already be advantageous before the actual Gautschnip (see, for example, FIG. 2). In this zone, only the pressure resulting from the wire tension (for example pre-wrapping, pre-gauze) is effective.

As can be seen, for example, from FIG. 3, a wrap of one of the two rubber elements, for example, can also advantageously be used to control the further web run (glass plate effect).

To activate the fines and fibers can be in front of the rubber points a steam blower box may be provided.  

LIST OF REFERENCE NUMBERS

10 ₁

to

10 ₄

Gautschnip

12

location

14

location

16

circulating band

18

circulating band

20

Aufgautschwalze

22

Gautschschuh

24

suction separator

26

Gautschschuhwalze

28

fourdrinier

30

roller

32

scree

34

Suction roll

36

pressing belt

38

tension roller

40

deflecting

42

deflecting

44

Aufgautschschuh
L web running direction

Claims (35)

1. Process for the production of a multilayer fibrous web, esp special paper or cardboard web, from a fiber suspension, in which the layers formed by a respective former coexist others are gossiped and especially in at least one Gautschnip through appropriate drainage and production supply a ge at least substantially perpendicular to the plane flow a fine material migration from zones higher Fines content to zones of lower fines content and / or from Zones of higher fiber entanglement to zones of lower fiber entanglement braid is enforced. 2. The method according to claim 1, characterized, that a corresponding fine material distribution in at least one formed between a Aufgautschwalze and a rubber shoe ten Gautschnip is enforced. 3. The method according to claim 1 or 2, characterized, that a corresponding fine material distribution in at least one  between a rubber roller and a rubber shoe roller formed Gautschnip is enforced. 4. The method according to any one of the preceding claims, characterized, that a corresponding fine material distribution in at least one Gautschnip formed between two rubber shoes becomes. 5. The method according to any one of the preceding claims, characterized, that a corresponding fine material distribution in at least one formed between a Aufgautschwalze and a pressure belt Gautschnip is enforced. 6. The method according to any one of the preceding claims, characterized, that the direction of fine matter migration is due to a disability and / or support for water leakage from the fiber track is influenced accordingly. 7. The method according to any one of the preceding claims, characterized, that a water spout on at least one side of the fibrous web guiding tape is led through the respective Gautschnip. 8. The method according to any one of the preceding claims, characterized,  that water on at least one side of the fibrous web permeable band with through the respective Gautschnip becomes. 9. The method according to any one of the preceding claims, characterized, that on at least one side of the fibrous web an impermeable Ges and non-storing tape with through the respective rubber nip is performed. 10. The method according to any one of the preceding claims, characterized, that the fibrous web in the respective Gautschnip at least one side is touched by a roller surface. 11. The method according to any one of the preceding claims, characterized, that in the area of a Gautschnips in the phase of Pressure increase of the gauzing or pressing concerned a pressure gradient from about 5 kPa / mm to about 50 kPa / mm or not in the area of the last Gautschnips up to about 100 kPa / mm is exceeded. 12. Process for producing a multi-layer fibrous web, esp special paper or cardboard web, from a fiber suspension, in which the layers formed by a respective former coexist others are spoiled, especially according to one of the previous ones existing claims,  characterized, that following at least one previous Gautschnip, d. H. following a Gautschnip, at least one Another Gautschnip follows, the dry content of the already multilayered Fibrous web on the side of the web on which there is at least one egg another layer is erected, in a range from about 7 to about 16%, preferably in a range from about 9 to about 14% lies and / or at least one of the subsequently to ver gumming partial webs a dry content in a range of about 7 to about 12%, preferably in a range of about 8 to owns about 10%. 13. The method according to any one of the preceding claims, characterized in that in a Gautschnip, followed by at least one further Gautschnip, with a basis weight of the already multi-layer fibrous web up to about 200 g / m ^2, a line force in a range from about 1 to about 100 kN / m, preferably in a range from about 5 to about 40 kN / m, and / or with a basis weight above about 200 g / m ² a line force in a range from about 1 to about 100 kN / m, preferably in one Range from about 2 to about 30 kN / m. 14. The method according to any one of the preceding claims, characterized in that in the area of the last Gautschnips at a basis weight of the multilayer fibrous web up to about 200 g / m ^2, a line force in a range from about 1 to about 300 kN / m, preferably in a range from about 5 to about 150 kN / m, and / or with a basis weight above about 200 g / m ² a line force in a range from about 1 to about 200 kN / m, preferably in a range from about 2 to about 100 kN / m, is generated. 15. The method according to any one of the preceding claims, characterized, that in the area of at least one Gautschnips a one-sided Ent watering takes place. 16. The method according to any one of the preceding claims, characterized, that at least in the web running direction before a respective Gautschnip least one of the partial webs to be rubberized together is pressed. 17. The method according to any one of the preceding claims, characterized, that to control the following a Gaut resulting web run a wrap one of the two rubber elements forming the Gautschnip is provided. 18. The method according to any one of the preceding claims, characterized, that the fine in the web running direction before a respective Gautschnip fabrics and fibers are activated by a steam box.   19. Sieve section of a machine for producing a multilayer fibrous web, in particular paper or cardboard web, in particular for carrying out the method according to one of the preceding claims, with at least one Gautschnip ( 10 ), in the layers formed by a respective former ( 12 , 14th ) are gassed with one another and by means of appropriate drainage and generation of a flow which is at least substantially perpendicular to the web plane, a fine material migration from zones of higher fine material content to zones of lower fine material content and / or from zones of higher fiber entanglement to zones of lower fiber entanglement can be forced. 20. Screen section according to claim 19, characterized in that at least one corresponding Gautschnip ( 10 ₁ ) is provided, which is formed between a Aufgautschwalze ( 20 ) and a rubber shoe ( 22 ). 21. Screen section according to claim 19 or 20, characterized in that at least one corresponding Gautschnip ( 10 ₂ ) is provided, which is formed between a Aufgautschwalze ( 20 ) and a Gautsch shoe roller ( 26 ). 22. Screen section according to one of the preceding claims, characterized, that at least one corresponding Gautschnip is provided, the is formed between two rubber shoes.   23. Screen section according to one of the preceding claims, characterized in that at least one corresponding Gautschnip ( 10 ₃ ) is provided, which is formed between a Aufgautschwalze ( 20 ) and a pressure belt ( 36 ). 24. Screen section according to one of the preceding claims, characterized, that a water spout on at least one side of the fibrous web guiding tape is led through the respective Gautschnip. 25. screen section according to one of the preceding claims, characterized, that water on at least one side of the fibrous web permeable band with through the respective Gautschnip is. 26. Screen section according to one of the preceding claims, characterized, that on at least one side of the fibrous web an impermeable Ges and non-storing tape with through the respective rubber nip is led. 27. Screen section according to one of the preceding claims, characterized, that the fibrous web in the respective Gautschnip at least one side is touched by a roller surface.   28. Screen section according to one of the preceding claims, characterized, that the maximum value of that in the area of a respective Gautschnips generated pressure gradients in a range of about 5 kPa / mm up to about 50 kPa / mm or in the area of the last Gautschnips bis is about 100 kPa / mm. 29. Sieve section of a machine for producing a multilayer fibrous web, in particular paper or cardboard web, in particular for carrying out the method according to one of the preceding claims, with at least one Gautschnip ( 10 ), in the layers formed by a respective former ( 12 , 14th ) are gassed together, in particular according to one of the preceding claims, characterized in that following at least one preceding Gautschnip, that is to say following a Gautschnip followed by at least one further Gautschnip, the dry content of the already multilayered fibrous web on the side of the Web, on which at least one additional layer is thickened, is in a range from about 7 to about 16%, preferably in a range from about 9 to about 14%, and / or at least one of the partial webs to be subsequently rubberized together has a dry content in a range from about 7 to about 12%, preferably in a range from about 8 to about 10%. 30. Sieve section according to one of the preceding claims, characterized in that the line force in the area of at least one preceding Gautschnip, ie following a Gautschnip, followed by at least one further Gautschnip, with a basis weight of the already multilayered fibrous web up to approximately 200 g / m ² in a range from about 1 to about 100 kN / m, preferably in a range from about 5 to about 40 kN / m, and / or with a surface weight above about 200 g / m ² in a range from about 1 up to about 100 kN / m, preferably in a range from about 2 to about 30 kN / m. 31. Sieve section according to one of the preceding claims, characterized in that the line force in the area of the last Gautschnips at a basis weight of the multilayer fibrous web up to about 200 g / m ² in a range from about 1 to about 300 kN / m, preferably in egg nem Range from about 5 to about 150 kN / m, and / or with a basis weight above about 200 g / m ² in a range from about 1 to about 200 kN / m, preferably in a range from about 2 to about 100 kN / m , lies. 32. wire section according to one of the preceding claims, characterized, that in a Gautschnip, at least one more Gautschnip follows, one-sided drainage takes place. 33. wire section according to one of the preceding claims, characterized, that means in the direction of the web in front of a respective Gautschnip  to pre-press at least one of the people the partial webs are provided. 34. Sieve section according to one of the preceding claims, characterized in that following a respective Gautschnip ( 10 ₃ ) after a loop ( 36 ) of one of the two Gautschnip ( 10 ₃ ) forming rubber elements ( 20 , 36 ) is present through the fibrous web. 35. wire section according to one of the preceding claims, characterized, that in the web running direction (L) before a respective Gautschnip Steam box is provided to the fines and fibers too activate.