DE10120636A1 - Method and device for the preparation of material used in particular for papermaking - Google Patents

Abstract

In the case of a process for the preparation of material which is used in particular for paper production, the material is cleaned, the cleaned material is soaked in a soaking screw and the soaked material is fed to a pulper. A corresponding device is also specified.

Description

The invention relates to a method and a device for processing processing of papermaking material in particular.

Pulp for the production of paper and cardboard is used in the paper machine upstream fiber preparation processed so that the ge wanted paper properties such as B. mechanical properties, op table properties, etc. can be achieved. The fiber can Additives, e.g. B. fillers are added.

Loading with an additive, e.g. B. filler, for example by a chemical precipitation reaction, d. H. especially by a so-called "Fiber Loading ™" process done as u. a. in U.S. Patent No. 5,223,090 is written. In such a "Fiber Loading ™" process to be wet fiber surfaces of the fiber material at least one additive, especially filler. The fibers can, for example be loaded with calcium carbonate. For this, the moist, the integrated fiber material calcium oxide and / or calcium hydroxide set that at least a part of it with that in the fiber material existing water associated. The fiber material treated in this way turns on finally loaded with carbon dioxide.  

The fiber suspension must also be used for this "Fiber Loading ™" process be pretreated accordingly. So far, a conventional one Processing system used, consisting of a dissolving unit, various sorting devices and drainage machines can exist.

The aim of the invention is to provide an improved method and an improved To create device of the type mentioned, in which the requ the effort is reduced to a minimum.

This object is achieved according to the invention by a method for opening preparation of, in particular, papermaking material, which the fabric cleaned, the cleaned fabric in a soaking screw soaked and the soaked substance is fed to a pulper.

Because of this configuration, the presses previously used for Drainage, in particular the usual sieve and Schnec presses, as well as the sorting devices that were previously used and cleaner. The calcium hydroxide or calcium oxide can if necessary directly in the Area of the soaking screw and / or in the area of the pulper be set. By reducing the number of machines results corresponding energy savings. Except for the cheaper one Operating mode also reduces the susceptibility to faults. Will the fibers loaded with additive through a "Fiber Loading ™" process the pulper dissolves the function of the usual pressure closure take a direction that can be dispensed with.  

Although the fibers contained in the fabric are preferably by a chemi cal precipitation reaction can be loaded with an auxiliary, he can methods according to the invention basically only for dissolving and oh ne the implementation of a "Fiber Loading ™" process the.

A soaking screw that is not pressurized is advantageously used used.

According to a preferred practical embodiment of the fiction According to the process, the substance in the soaking screw is preferred by spraying with liquid, especially water, onto a fabric density in a range from about 15% to about 40%, preferably in egg soaked in a range from about 20% to about 35%. Soaking should be done as gently as possible. This can correspond, for example appropriate spray systems or the like are used.

The softened substance is advantageously in the pulper at egg ner consistency in a range from about 15% to about 35%, preferably wise in a range from about 20% to about 35%, at least in the we substantially completely dissolved.

The dissolved substance can then in particular be a device for Bela that of the fibers, especially according to the "Fiber Loading ™" Process. As already mentioned, the implementation is egg However, the corresponding "Fiber Loading ™" process is not mandatory. For example, the method according to the invention can also only be used for Dissolving can be applied.  

A pulper or pulper is advantageously used, the one Housing with a fiber inlet, at least one water inlet, little least has an outlet and an inner chamber and a Mehr Number of connected to the housing, moving into the inner chamber stationary dissolving elements as well as one through the inner Chamber extending shaft includes around in the area of the fiber inlet a snail is arranged and the we a plurality of itself stretching movable opening elements. A corresponding one Dissolver is described in US 09 440 225. Otherwise, too the solubilizer can in particular be designed as described in this US 09 440 225 is specified. So the solubilizer in the area of its out For example, let a Ven preferably designed as a throttle cone til include. Basically, however, is also an execution without one such valve possible.

The pre-sorted and cleaned material can be, for example, in bale form provided and by means of a conveyor, in particular a conveyor belt or the like, via a wiring device with integrated Magnetic separator are fed to the soaking screw.

The substance to be dissolved can in particular be any one act against paper raw material, provided that the substance in question is free from impurities is and has a raw material quality of pulp.

As mentioned earlier, the substance can be used for the chemical precipitation reaction for example calcium hydroxide and / or calcium oxide can be added. In this case, precipitated calcium carbonate is preferably used as an auxiliary generated.  

The calcium hydroxide or calcium oxide can, for example, in the range added to the soaking screw and / or in the area of the pulper become.

Calcium hydroxide is advantageously in liquid form with a substance density in a range from about 1% to about 60% (mass%), preferably as in a range from about 15% to 25%, and / or calcium oxide Solid form added.

If calcium oxide is added, the soaking drum or - Snail-fed water can be used with the calcium oxide calcium hydroxide to form, which is then in the following "Fiber Loa ding ™ "process after adding carbon dioxide to calcium carbonate can be converted.

In certain cases it is advantageous if the calcium hydroxide or Calcium oxide only after the soaking screw and after the substance dissolver is added.

According to a preferred practical embodiment of the fiction According to the process, the substance is added to the substance dissolver Pump disperger or -fluffer supplied and in this by shear forces applied to larger fiber agglomerates in smaller or even in indi break up vidual fibers, with the pump disperger or buffer in front preferably at the same time ver as a reactor for the chemical precipitation reaction is applied.  

A pump disperger or buffer is preferably used, the sen reaction channel between two opposite, relative rotating plates or the like with structured upper areas is formed, the substance in this reaction channel in general is transported radially outwards.

Such a pump disperser or buffer is not yet published in the lichten DE 101 07 448.4 described. The pump can also do the rest disperger or buffer can be designed as described in this DE 101 07 448.4 is specified.

In the area of its outlet, the pulper comprises a preferably as Throttle plug designed valve, this is the pump disperger or buffer sealed on the inlet side by this valve of the pulper. An ab seal by forming a plug of material in the area in front of the pump dis perger or buffer is no longer necessary.

According to another expedient embodiment of the invention The pump disperger or -fluffer is on the inlet side sealed that the substance compacted to form a plug and the material compacted into a plug to the pump disperger or buffer is fed. In this case, it can be designed as a throttle cone Valve of the pulper is not required.

A separately drivable is preferably used to form the plug of material Graft screw provided.  

If the fibers are to be loaded with the filler calcium carbonate, so it is an advantage if in the area of the pump disperger or fluffer Carbon dioxide is introduced and the pump disperger or buffer equal early as a reactor for the implementation of the starting materials mentioned moxide or calcium hydroxide and carbon dioxide in the reaction products Calcium carbonate and water is used in its reaction channel the flow rate of the fiber suspension is preferably reduced becomes.

When loading the fibers with calcium carbonate (CaCO ₃ ), this is stored on the wetted fiber surfaces by adding calcium oxide (CaO) and / or calcium hydroxide (Ca (OH) ₂ ) to the moist fiber material, at least some of which mix with the water Associate amount of fiber. The fiber material treated in this way can then be loaded with carbon dioxide (CO ₂ ).

The term "wetted fiber surfaces" can mean all wetted surfaces of the individual fibers. This is especially the case with detected, in which the fibers both on their outer surface and in their Inside (lumen) with calcium carbonate or any other precipitate loading product.

Accordingly, the fibers can e.g. B. with the filler calcium carbonate be loaded, being attached to the wetted fiber surfaces by a so-called "Fiber Loading ™" process, as it is in the US-A-5 223 090. In this "Fiber Loading ™" process rea yaws z. B. the carbon dioxide with the calcium hydroxide to water and Calcium carbonate.  

The device according to the invention for processing in particular the Correspondingly, papermaking material includes agents for cleaning against the fabric, a soaking screw for soaking the cleaned Fabric and a fabric dissolver to dissolve the soaked fabric.

Preferred embodiments of the device 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 is a simplified schematic representation of the essential method steps of the material processing,

Fig. 2 is a schematic representation of a corresponding stock preparation device and

Fig. 3 is a view of the Pumpdispergers or -fluffers in the direction of arrows A in FIG. 2.

Fig. 1 shows a simplified schematic representation of the essential process steps of an exemplary embodiment of the method for the preparation of material used in particular for papermaking.

Then in step "1" the pre-sorted and cleaned material is bale form saved and provided.  

In steps "2" and "3", the cleaned substance is then removed using a Conveyor, in particular a conveyor belt or the like, for example as a wire removal device with integrated magnet Schneider fed a soaking screw, by means of which the material is then in the Step "4" is soaked. In step "3", in particular, a Separation take place and for removing metal parts such. B. a metal detector can be used. Between steps "3" and "4" you can at for example, a shredder can be used.

The soaked substance is a pulper or pulper in step "5" fed.

In step "6" the dissolved substance can be loaded with an auxiliary such as calcium carbonate, in particular by a so-called "Fiber Loading ™" process by a chemical precipitation reaction. If the fibers are loaded with calcium carbonate, calcium hydroxide (Ca (OH) ₂ ) and / or calcium oxide (CaO) is added to the substance for the corresponding chemical precipitation reaction. The calcium hydroxide or calcium oxide z. B. in the area of optionally z. B. between steps "3" and "4" shredders used, in the area of the soaking screw (cf. step "4") and / or in the area of the pulverizer or pulp used in step "5". If calcium oxide is added, the water supplied at the point in question is used to form with this calcium hydroxide, which is then converted into calcium carbonate in step "6" relating to the "Fiber Loading ™" process with the addition of carbon dioxide (CO ₂ ) ,

Following the "Fiber Loading ™" step "6", the loaded material is fed to the relevant paper machine (cf. step 7 ).

Fig. 2 shows a schematic representation of a corresponding stock preparation device 10 , which in particular can be provided again for the processing of the papermaking material.

The device 10 comprises means (not shown) for cleaning the substance, a soaking screw 12 for soaking the cleaned substance, a substance dissolver or pulper 14 for dissolving the soaked substance and a device serving as a reactor for the chemical precipitation reaction, which in the present exemplary embodiment as Pumpdisper ger or -fluffer 16 is executed and is used in particular to carry out a "Fiber Loading ™" process.

The preferably not pressurized soaking screw 12 comprises a soaking drum 18 and an extending in this Schnec kenelement 20 , through which the introduced via an inlet 22 cleaned material is conveyed to an outlet 24 .

As can be seen from FIG. 1, the cleaned material of the soaking screw 12 can be supplied, for example, with a material density in a range of approximately 15% to approximately 40%.

The soaking screw 12 is provided with spraying agents or a spraying system 26 in order to spray the substance introduced into the soaking drum 18 with liquid, in particular water, and to appropriately soak.

The shaft 28 carrying the screw element 20 can be driven via a drive 30 , in the area of which the shaft 28 is mounted in a bearing 32 . Appropriate storage is also hen at the other end of the shaft.

The soaked substance is then fed to the pulper 14 . This pulper 14 includes a housing 34 having a fiber or fabric inlet 36 , at least one water inlet 38 , at least one outlet 40 and an inner chamber 42 . In addition, this pulper 14 has a plurality of connected to the housing 34 , extending into the inner chamber 42 extending resolving elements 44 and a shaft 46 extending through the inner chamber, around which a screw 48 is arranged in the region of the fiber inlet 36 and which carries a plurality of movable trigger members 50 extending therefrom. These opening elements 50 thus rotate with the shaft 46 which is driven via an external drive 52 . The shaft is supported in two bearings 54 arranged outside the housing 34 .

In the area of its outlet 40 , the pulper 14 is provided with a valve 56 , which in the present case is designed as a throttle cone. The outlet quantity can be set accordingly via this valve.

Following the pulper 14 , the pulp is fed to the pump disperger or buffer 16 and is subjected to shear forces in it in order to break up larger fiber agglomerates into smaller or even individual fibers.

In the present exemplary embodiment, the pump disperger or fluffer 16 also serves as a device or reactor for a chemical precipitation reaction. For this purpose, this pump disperger or buffer 16 can have a reaction channel 58 , which is formed between two mutually opposite, relatively rotating plates 60 or the like with structured surfaces 60 '. The material is generally transported radially outward in this reaction channel 60 .

As can be seen from FIG. 2, the reaction channel 58 can be preceded by a feed screw 62 which is arranged in an at least essentially cylindrical channel or housing 64 .

The cylindrical channel 64 may have an inlet 66 for supplying the substance coming from the dissolver 14 .

In the present exemplary embodiment, the pump disperger or buffer 16 is sealed on the inlet side by the valve 40 of the pulper 14 designed as a throttle cone. However, the pump disperger or buffer 16 can also be sealed on the inlet side, for example, in that the substance is compacted by means of a plug screw, which can preferably be driven separately, to form a plug, and the material sealed to a plug is fed to the pump disperser or buffer 16. In this case, the valve 40 formed by a throttle cone can be omitted.

The pump disperger or buffer 16 can also be provided as a reactor for converting the starting materials calcium oxide or calcium hydroxide and carbon dioxide into the reaction products calcium carbonate and water. The calcium hydroxide or calcium oxide can be added, for example, in the area of the soaking screw and / or in the area of the pulper 14 . The carbon dioxide can be supplied in the area of the pump disperger or buffer 16.

The pump disperger or buffer 16 can thus in particular form the reactor for converting the starting materials calcium oxide or calcium hydroxide and carbon dioxide into the reaction products calcium carbonate and water. In the reaction channel 58 formed between the two plates 60 with structured surface, the material is transported radially outward and loaded with calcium carbonate.

The relative speed of the two opposing plates 60 or structured surfaces is preferably adjustable, with at least one plate rotating. Alternatively or additionally, the absolute speed can also be adjustable. In particular, the discharge speed can be influenced.

As can be seen in particular with reference to FIG. 3, a swirl cross 68 can be provided in the center of the pump disperger or fluff 16, through which the material is loosened further and the areas of the fiber material are increased accordingly.

The pump disperger or buffer 16 can have an outlet 70 , which is at least substantially tangential to the plates 60 or structured surfaces, for the loaded material. In addition, the pump disperger or buffer 16 can have an inlet 72 arranged at least substantially tangentially to the plates 60 or structured surfaces 60 'for diluting the loaded substance with water and / or calcium hydroxide.

In addition, the pump disperger or buffer 16 can be equipped with a heating device be provided, via which the reaction temperature can be influenced.

In Fig. 2 exemplary material densities are given at various points. For example, the consistency in the area of the inlet 22 of the soft screw 12 can be 15% to 40%, in the area of the inlet 66 of the pump disperger or buffer 16 for example 15% to 35% and in the area of the outlet 70 of the pump disperger or buffer 16 for example, 3% to 5%. In principle, however, other density values are also possible.

The following chemical reaction occurs in the pump disperger or buffer 16 serving as a reactor.

"Fiber Loading ™": Ca (OH) ₂ + CO ₂ → CaCO ₃ + H ₂ O (calcium carbonate + water)

LIST OF REFERENCE NUMBERS

10

Material preparation apparatus

12

Einweichschnecke

14

Dissolver, pulper

16

"Fiber Loading ™" device, reactor, pump disperger or fluffer

18

steeping

20

screw element

22

Inlet

24

outlet

26

Spray agent, system

28

wave

30

drive

32

camp

34

casing

36

Fiber or fabric inlet

38

water inlet

40

outlet

42

inner chamber

44

stationary opening element

46

wave

48

slug

50

sears

52

drive

54

camp

56

Valve, throttle plug

58

reaction channel

60

plate

60

'' structured surface

62

feed screw

64

Channel, housing

66

Inlet

68

swirl cross

70

outlet

72

Intake

Claims (42)

1. A process for the preparation of, in particular, papermaking substance, in which the substance is cleaned, the cleaned substance is soaked in a soaking screw ( 12 ) and the soaked substance is fed to a pulper ( 14 ). 2. The method according to claim 1, characterized, that the fibers contained in the fabric by chemical precipitation reaction are loaded with an auxiliary. 3. The method according to claim 1 or 2, characterized in that a non-pressurized soaking screw ( 12 ) is used. 4. The method according to any one of the preceding claims, characterized in that the substance in the soaking screw ( 12 ) preferably by spraying with liquid, in particular water, to a density in a range from about 15% to about 40%, preferably in egg nem Range from about 20% to about 35%. 5. The method according to any one of the preceding claims, characterized in that the softened substance in the pulper ( 12 ) at a substance density in a range from about 15% to about 35%, preferably in a range from about 20% to about 35% , at least essentially completely resolved. 6. The method according to any one of the preceding claims, characterized in that the dissolved substance is fed to a device ( 16 ) for loading the Fa sern. 7. The method according to any one of the preceding claims, characterized in that a pulper ( 14 ) is used which has a housing ( 34 ) with a fiber inlet ( 36 ), at least one water inlet ( 38 ), least one outlet ( 40 ) and one inner chamber ( 42 ) and includes a plurality of stationary disengagement elements ( 44 ) connected to the housing ( 34 ), extending into the inner chamber ( 42 ), and a shaft ( 46 ) extending through the inner chamber ( 42 ) a screw ( 48 ) is arranged in the region of the fiber inlet ( 36 ) and bears a plurality of movable opening elements ( 50 ) extending away from it. 8. The method according to claim 7, characterized in that the pulper ( 14 ) in the region of its outlet ( 40 ) comprises a valve ( 56 ) which is preferably designed as a throttle cone. 9. The method according to any one of the preceding claims, characterized in that the pre-sorted and cleaned material is provided in bale form and is fed to the soaking screw ( 12 ) by means of a conveyor, in particular a conveyor belt, via a wire removal device with an integrated magnetic separator. 10. The method according to any one of the preceding claims, characterized, that the substance for the chemical precipitation reaction calcium hydroxide and / or calcium oxide is added. 11. The method according to claim 10, characterized, that precipitated calcium carbonate is produced as an auxiliary. 12. The method according to claim 10 or 11, characterized in that the calcium hydroxide or calcium oxide in the area of a soft screw ( 12 ) and / or in the area of the pulper ( 14 ) is set. 13. The method according to any one of the preceding claims, characterized, that calcium hydroxide in liquid form with a consistency in one Range from about 1% to about 60%, preferably in a range from about 15% to about 25%, and / or calcium oxide in solid form is added.   14. The method according to any one of the preceding claims, characterized in that calcium oxide is added in order to form calcium hydroxide with the soaking screw ( 12 ) supplied water. 15. The method according to any one of the preceding claims, characterized in that the calcium hydroxide or calcium oxide is added only after the soaking screw ( 12 ) and after the pulper ( 14 ). 16. The method according to any one of the preceding claims, characterized in that the substance following the substance dissolver ( 14 ) a pump disperger or -fluffer ( 16 ) and in this is acted upon by shear forces to larger fiber agglomerates in smaller or even in Break individual fibers, the Pumpdis perger or -fluffer ( 16 ) is preferably used simultaneously as a device or reactor for the chemical precipitation reaction. 17. The method according to claim 16, characterized in that a pump disperger or buffer ( 16 ) is used, the reaction channel ( 58 ) between two mutually opposite, relatively rotating plates ( 60 ) or the like with structured surfaces ( 60 ' ) is formed, the substance in this reaction channel ( 58 ) being transported generally radially outwards. 18. The method according to claim 17, characterized in that the pulper ( 14 ) in the region of its outlet ( 40 ) comprises a valve ( 56 ) preferably designed as a throttle cone and that the pump disperger or buffer ( 16 ) on the inlet side through this valve ( 56 ) of the pulper ( 14 ) is sealed. 19. The method according to claim 17, characterized in that the pump disperger or buffer ( 16 ) is sealed on the inlet side by the fact that the material is compacted to form a plug and the material compressed to a plug is supplied to the pump disperser or buffer ( 16 ) , 20. The method according to claim 19, characterized, that a separately drivable plug to form the plug screw is used. 21. The method according to any one of the preceding claims, characterized in that carbon dioxide is introduced in the region of the pump disperser or buffer ( 16 ) and the pump disperser or buffer at the same time as a reactor for converting the starting materials mentioned calcium oxide or calcium hydroxide and carbon dioxide into the reaction products calcium carbonate and water is used, in the reaction channel ( 58 ) of which the flow rate of the fiber suspension is preferably reduced. 22. The device ( 10 ) for the preparation, in particular, of the papermaking product, with means for cleaning the fabric, with a soaking screw ( 12 ) for soaking the cleaned fabric and with a fabric dissolver ( 14 ) for dissolving the soaked fabric. 23. The device according to claim 22, characterized in that it comprises a device ( 16 ) to load the fibers contained in the substance by a chemical precipitation reaction with an auxiliary. 24. The device according to claim 22 or 23, characterized in that the soaking screw ( 12 ) is not pressurized. 25. Device according to one of the preceding claims, characterized in that means ( 26 ) are provided to the material in the soaking screw ( 12 ) preferably by spraying with liquid, in particular water, to a material density in a range of about 15% up to about 40%, preferably in a range from about 20% to about 35%. 26. Device according to one of the preceding claims, characterized in that the softened substance in the pulper ( 14 ) at a substance density in a range from about 15% to about 35%, preferably in a range from about 20% to about 35%, at least essentially completely resolved. 27. The device according to any one of the preceding claims, characterized in that the dissolved substance of the device ( 16 ) for loading the Fa sern is supplied. 28. Device according to one of the preceding claims, characterized in that the pulper ( 14 ) has a housing ( 34 ) with a fiber inlet ( 36 ), at least one water inlet ( 38 ), at least one outlet ( 40 ) and an inner chamber ( 42 ) comprising a plurality of stationary disengagement elements ( 44 ) connected to the housing ( 34 ) and extending into the inner chamber ( 42 ) as well as a shaft ( 46 ) extending through the inner chamber around which in the region of the fiber inlet ( 36 ) a worm ( 48 ) is arranged and carries a plurality of movable disengagement elements ( 50 ) extending therefrom. 29. The device according to claim 28, characterized in that the pulper ( 14 ) in the region of its outlet ( 40 ) comprises a valve ( 56 ) which is preferably designed as a throttle cone. 30. Device according to one of the preceding claims, characterized in that the pre-sorted and cleaned material provided in bale form can be fed to the soaking screw ( 12 ) by means of a conveyor, in particular a conveyor belt, via a wire removal device with an integrated magnetic separator. 31. Device according to one of the preceding claims, characterized, that means are provided to precipitate the chemical reaction to add calcium hydroxide and / or calcium oxide. 32. Device according to claim 31, characterized, that precipitated calcium carbonate is provided as an auxiliary. 33. Apparatus according to claim 31 or 32, characterized in that means are provided to add the calcium hydroxide or calcium oxide in the area of the soaking screw ( 12 ) and / or in the area of the pulper ( 14 ). 34. Device according to one of the preceding claims, characterized, that calcium hydroxide in liquid form with a consistency in one Range from about 1% to about 60%, preferably in a range from about 15% to about 25%, and / or calcium oxide in solid form is added.   35. Device according to one of the preceding claims, characterized in that calcium oxide is added in order to form calcium hydroxide with the water supplied by the soaking screw ( 12 ). 36. Device according to one of the preceding claims, characterized in that the calcium hydroxide or calcium oxide is added only after the soaking screw ( 12 ) and after the pulper ( 14 ). 37. Device according to one of the preceding claims, characterized in that the substance following the substance dissolver ( 14 ) is supplied to a pump disperger or buffer ( 16 ) and in this is acted upon by shear forces to larger fiber agglomerates in smaller or even in Break up individual fibers, the pump disper or buffer ( 16 ) preferably being provided at the same time as a device or reactor for the chemical precipitation reaction. 38. Apparatus according to claim 37, characterized in that the pump disperger or buffer ( 16 ) has a reaction channel ( 58 ) between two mutually opposite, relatively rotating plates ( 60 ) or the like with structured surfaces ( 60 ') is formed, the substance in this reaction channel ( 58 ) is generally transported radially outward. 39. Apparatus according to claim 38, characterized in that the pulper ( 14 ) in the region of its outlet ( 40 ) comprises a valve ( 56 ) which is preferably designed as a throttle cone and that the pump disperger or buffer ( 16 ) on the inlet side through this valve ( 56 ) of the pulper ( 14 ) is sealed. 40. Apparatus according to claim 38, characterized in that the pump disperger or buffer ( 16 ) is sealed on the inlet side by the fact that the material is compacted to form a plug and the material compressed to a plug is supplied to the pump disperser or buffer ( 16 ) , 41. Device according to claim 40, characterized, that a separately drivable plug to form the plug fne screw is provided. 42. Device according to one of the preceding claims, characterized in that means are provided in order to introduce carbon dioxide in the area of the pump disperger or buffer ( 16 ), and that the pump disperger or buffer ( 16 ) simultaneously as a reactor for converting the starting materials mentioned Calcium oxide or calcium hydroxide and carbon dioxide in the reaction products calcium carbonate and water is provided, in the reaction channel ( 58 ) the Fließge speed of the fiber suspension is preferably reduced.