WO2003091499A1

WO2003091499A1 - Method for production of a tissue web

Info

Publication number: WO2003091499A1
Application number: PCT/EP2003/050074
Authority: WO
Inventors: Thomas Thoröe Scherb
Original assignee: Voith Paper Patent Gmbh
Priority date: 2002-04-25
Filing date: 2003-03-20
Publication date: 2003-11-06
Also published as: JP2009185442A; BR0308838A; EP1501981A1; CA2713601C; BRPI0308838B1; EP1501981B1; DE10218509A1; AU2003219169A1; CA2483818A1; EP2481849A1; CA2483818C; JP2005521808A; JP4338081B2; CA2713601A1

Abstract

The invention relates to a method for production of a tissue web (12) by means of a tissue machine (10) with a pulp outlet (14) and an endless support belt (16), by means of which the tissue web is run through a press gap (22) formed with a drying cylinder (18) and a counter-unit (20), whereby a multi-layer pulp outlet is used as pulp outlet. Said multi-layer pulp outlet supplies at least two different types of pulp. Leading from the press gap the tissue web is wound by means of a winding device (24). The hardness of the ensuing roll (80) is thus preferably influenced in a given manner, in particularly controlled and/or regulated. A corresponding tissue machine is also disclosed.

Description

Process for making a tissue web

The invention relates to a method for producing a tissue web. In particular, these can be such types of tissue as, for example, “toilet tissue”, “facial tissue”, napkin paper and / or the like. In addition, the invention relates to a tissue machine for performing the method.

In the case of the aforementioned types of tissue in particular, the specific volume ("bulk", measured in [cm ³ / g]), which should be as high as possible, and the so-called "hand feel", which is a measure of this, are important how pleasant the tissue, e.g. facial tissue, feels when you grasp it. Since this measure depends on the subjective perception of the consumer, there is still no objective measurement method. Properties such as softness, velvety, flat surface topography (in contrast to coarsely creped and / or embossed surfaces) favor a high degree of "hand feel". A "handfeel" value is called

Result determined from the subjective evaluation of a large number of test subjects.

A certain minimum strength is of course also important for such a tissue product, which meets the requirements of the consumer.

Several tissue machine concepts have been proposed that generally aim to improve tissue properties. The aim of the invention is to provide an improved method and an improved tissue machine of the type mentioned at the outset with which a tissue product or tissue paper, in particular "toilet tissue" and "facial tissue", with a particularly high "hand feel" and a high level specific volume (bulk) with acceptable strength is guaranteed. With a "facial tissue" of an area-related mass (FbM) of, for example, 15 g / m ² , a specific volume (bulk) of 10 cm ³ / g and higher, and with an area-related mass (FbM) of 23 g / m ² a specific volume (bulk) of 9.0 cm ³ / g and higher is aimed for. In addition, the tissue machine in question should be as simple and inexpensive in construction as possible. At the same time, as many different product types as possible should be able to be produced on this machine.

According to the invention, this object is achieved by a method for producing a tissue web by means of a tissue machine with a headbox and an endless carrier belt, with which the tissue web is guided through a press nip formed between a drying cylinder and a counter unit, a multilayer headbox being used as the headbox. at least two types of material are fed to this multi-layer headbox and the tissue web is wound up following the press nip by means of a winding device, the hardness of the resulting roll preferably being influenced, in particular controlled and / or regulated, in a predeterminable manner.

A Yankee cylinder is preferably used as the drying cylinder. The line force generated in the winding gap is expediently chosen to be less than or equal to 0.8 kN / m.

According to a preferred practical embodiment of the method according to the invention, a former with two circulating endless belts is used, which converge to form a material inlet gap and are then guided over a forming element, such as in particular a forming roller, the inner belt preferably coming into contact with the forming element being the conveyor belt forms. A crescent former is preferably used, the inner band of which is formed by a felt band.

It is also particularly advantageous if the tissue web is passed through at least one shoe press together with the carrier tape. A shoe press unit is expediently used as the counter unit assigned to the drying cylinder.

A high-temperature hood can be provided over the drying cylinder or Yankee cylinder.

A further improvement in the tissue product properties can in particular also be achieved in that the tissue web is scraped off the drying cylinder by means of a particularly thin crepe scraper.

One or more of the following types of substance are preferably used:

Hardwood fibers, especially short fiber pulps Soft wood fibers, especially long fiber pulps CTMP (Chemical-thermo mechanical Pulp).

Mixtures of substances are preferred in which the proportion of hardwood fibers in a range from approximately 50% to approximately 80%, the proportion of softwood fibers in a range from approximately 20% to approximately 50% and / or the proportion of CTMP ( Chemical-thermo-mechanical pulp) is in a range from 0% to about 20%.

Among other things, For example, the following mixtures of substance types are conceivable:

Ex. "A" Ex. "B" Ex. "C"

Hardwood (50 to 80%) 50 60 70

Softwood (20 to 50%) 30 40 20

CTMP (0 to 20%) 20 0 10

In particular, the CTMP in a particular mixture of substances improves the specific volume (bulk).

According to a preferred practical embodiment of the method according to the invention, the tissue web is guided around the drying cylinder following the press nip, the drying in the relevant wrapping area preferably being reinforced by a drying hood, in particular a high-temperature hood.

It is particularly advantageous if at least two different types of material are added to the multi-layer headbox and, in the process, short fibers obtained from hardwood for the layer of the tissue web facing the drying cylinder surface and for those on the opposite one On the web side, a layer of long fibers obtained from softwood can be used.

It is therefore particularly advantageous if the headbox is loaded with at least two layers of different fiber materials, the material with short fibers obtained from hardwood being added to the headbox layer facing the side of the tissue web that faces the drying or Yankee cylinder surface forms. The second layer is expediently loaded with long softwood fibers. Alternatively or additionally, this second layer can also be loaded with long fibers and CTMP and / or with long fibers and CMP and short fibers. This layer forms the second layer of the tissue web and faces the drying hood during the drying process. So it never comes into contact with the dry or Yankee cylinder surface. With these process steps, the "handfeel" and "bulk" values are improved by approximately 5% and more.

A multilayer headbox is advantageously used, the nozzle of which is divided into at least two channels by at least one lamella which extends over the entire width of the machine. The nozzle is expediently divided into two channels at least essentially symmetrically by a lamella.

Particularly good results are obtained if the lamella extends outward beyond the nozzle in the area of the outlet gap. This counteracts a mixing of the layers.

Advantageously, a headbox with a dilution water control and / or control that is sectional across the machine width can be used in order to be able to set a desired basis weight cross profile.

In certain cases it is advantageous if a dilution water control and / or control is provided for at least two layers. For example, when using a two-layer headbox, a dilution water regulation or control can be provided in each of the two layers.

A dilution water control and / or control is preferably provided at least for the layer facing the forming or breast roll. In particular, only for this one layer, i.e. the outer layer with respect to the forming roll or breast roll, a relevant dilution water control and / or control can be provided. The forming or breast roller can be closed, open or even vacuumed.

Important for the drying process is the drying of the web by the drying or Yankee cylinder and a drying or hot air hood, whereby according to a preferred practical embodiment of the method according to the invention, the proportion of drying contributed by the drying hood to dry the tissue web is chosen to be greater than that the amount of drying contributed by the drying cylinder.

The ratio between the drying proportion of the drying hood and the drying proportion of the drying cylinder is advantageously chosen to be greater than 55:45, in particular greater than or equal to 60:30, particularly greater than or equal to 65:35 and preferably greater than or equal to 70:30. The drying hood is preferably operated at a temperature which is greater than or equal to 400 ° C., in particular greater than or equal to 500 ° C., in particular greater than or equal to 600 ° C. and preferably greater than or equal to 700 ° C.

The steam pressure in the drying cylinder can also be reduced. Thus, a value is advantageously chosen for the steam pressure in the drying cylinder that is less than or equal to 0.7 MPa, in particular less than or equal to 0.6 MPa and preferably less than or equal to 0.5 MPa.

This can further increase the drying process. The measures mentioned increase the "bulk" value by up to + 5% and improve the "handfeel" value.

Of particular importance is also the winding of the tissue web at the end of the tissue machine.

According to a preferred practical embodiment of the method according to the invention, a winding device (roller apparatus) is used in which the tissue web is guided over a carrying drum and then wound onto a spool, preferably with a drive assigned to both the carrying drum and the spool is. This ensures optimal winding of the web without destroying the specific volume (bulk) of the paper web produced. With the use of two drives for the carrier drum and the reel or the winding roll, it is possible in particular to reduce the line force generated in the winding gap. According to an expedient practical embodiment of the method according to the invention, the line force generated in the winding gap between the carrier drum and the drum is less than or equal to 0.8 kN / m, in particular less than or equal to 0.5 kN / m and preferably less than or equal to 0.2 kN / m selected. Since no drive power has to be transmitted between the carrier drum and the winding roll, the pressure in the winding gap or contact nip can be reduced.

Since tissue paper is creped, high elongation, i.e. has a high modulus of elasticity and has a low tensile strength, no substantial web tension can be applied to increase the winding hardness of the winding roll.

The maximum difference between the peripheral speed of the winding and the peripheral speed of the idler roller is preferably less than 10% of the peripheral speed of the idler roller.

According to a preferred practical embodiment of the method according to the invention, the web tension between the drying cylinder and the support drum is set to a predefinable setpoint value, in particular controlled and / or regulated, via the drive assigned to the support drum independently of the line force generated in the winding nip.

Due to the creping on the creping scraper, the peripheral drum speed is lower than the peripheral speed of the drying cylinder. The drive associated with the drum is advantageously controlled and / or regulated as a function of the speed of the carrying drum.

The control of the "small" line force in the winding gap or contact nip is of particular importance when producing a soft winding. According to a preferred practical embodiment of the method according to the invention, a winding device is used for this purpose, in which the carrying drum is mounted in a stationary manner and the drum can be moved. Correspondingly, the increase in the winding diameter can be compensated for by a corresponding method of the spool. In addition, the line force in the winding nip can be adjusted in the desired manner using the movable reel. A common control loop can advantageously be used to compensate for the increase in winding diameter and to adjust the line force in the winding gap. An expedient embodiment of the method according to the invention is characterized in that the line force in the winding gap is determined via at least one force sensor and this line force is regulated by a corresponding method of the spool. In principle, however, the drum can, for example, also be stationary and the carrying drum can be moved. In addition, designs are also conceivable in which both the carrying drum and the drum can each be moved.

The measuring accuracy of the sensors and the setting accuracy (friction) with small line forces and large, heavy winding rolls may no longer be sufficient. In particular with linear forces in the winding gap that are less than or equal to 0.5 kN / m and in particular less than or equal to 0.2 kN / m, the movable drum is therefore preferably path-controlled. In this case, in particular the winding diameter and the position of the drum or the winding formed thereon can be used relative to the carrying drum.

According to a further advantageous embodiment of the method according to the invention, the area of the winding gap can be appropriately monitored by means of a CCD camera in order to set or control and / or regulate the line force in the winding gap. The CCD camera preferably detects the respective distance between the carrying drum and the drum or the roll formed thereon. With such an observation of the winding gap area z. B. by means of a CCD camera so there is another way to control and adjust the winding force. It is thus possible to measure and display the distance between the carrier drum and the winding roll. On the basis of an evaluation of the image, a setpoint for the hydraulic cylinder pressure influencing the movable winding roll can again be achieved and the displacement or displacement up to the desired distance or winding force can be carried out by means of a control device. The bulk gain can range, for example, from 4 to 8%. Another advantage is that the "bulk" profit achieved by the shoe press is not destroyed and the quality of the web is thus maintained.

It is particularly advantageous if the drive assigned to the spool and thus the winding roll is not changed during the winding process, ie in particular not even if the new spool from the spool bearing via the primary or on winding position in which the drive is coupled and the reel is accelerated, moved to the secondary position on the rails. This results in controlled winding from the beginning to the end. The paper quality can be further increased in that the area-related mass of the tissue web in the uncreped state in a range from approximately 11 g / m ² to approximately 20 g / m ² and in the creped state in a range from approximately 14 g / m ² to is about 24 g / m ² .

Since especially with thin papers and especially with "Facial Tissue" and "Toilet" tissue, the formation, i.e. Uniformity of the fiber arrangement plays an important role, the use of a crescent former is particularly advantageous in these cases. The web is dewatered on a felt, transported, pressed and passed on to the drying cylinder or Yankee cylinder. At the beginning of the drainage, an external sieve is also provided. In addition to an improved formation, there is also an improved strength with possible tear length ratios lengthways / crossways from 1: 1 to 4: 1. This makes it possible to grind the fibers less. This increases the "bulk" value. This type of former can be used to convert "strength" into "bulk". This type of former improves the specific volume (bulk) in combination with at least one of the described embodiment variants by +5%.

In particular, a crescent former can be used, the inner or carrier band formed by a felt band, together with the tissue web, being guided in the web running direction in front of the press nip via at least one suctioned device. In particular, a suction roller can be provided as the suction device. As already mentioned, the outer belt provided in the area of the forming element of the crescent former can in particular be formed by a wire belt.

The use of a shoe press with a shoe length measured in the direction of web travel is particularly advantageous greater than or equal to 80 mm and preferably greater than or equal to 120 mm. A line force which is in a range from 60 kN / m to approximately 90 kN / m is preferably generated by means of the shoe press. The maximum press pressure in the press nip of the shoe press is preferably less than or equal to 2 bar and preferably less than or equal to 1.5 bar. The shoe press can also comprise a shoe press unit with a blind-drilled press jacket. Compared to a suction press roll, a bulk gain in a range from about 15% to about 20% can be achieved.

According to an expedient practical embodiment of the method according to the invention, a drying cylinder or Yankee cylinder provided on the inside with reinforcing ribs is used, as a result of which the line force generated in the press nip can also be increased significantly above 90 kN / m. This makes the tissue machine more flexible, especially in the case that, in addition to the "Facial" and "Toilet" tissue papers, tissue types are also used in which not the "handfeel" and the specific volume (bulk) have the first priority, but the dry content , ie the production level.

As already mentioned, a relatively thin creping doctor is preferably used. The thickness of the creping doctor can in particular be less than or equal to 0.9 mm.

The angle of attack between the tangent to the drying cylinder and the creping doctor is preferably less than or equal to 20 °.

The so-called "rake angle" can in particular be greater than or equal to 15 ° in this crepe doctor. The object specified at the outset is also achieved according to the invention by a machine for producing a tissue web with a headbox and an endless carrier belt with which the tissue web is guided through a press nip formed between a drying cylinder and a counter unit, and with a winding device for the subsequent winding of the Tissue web, a multi-layer headbox being provided as the headbox, to which at least two types of material can be fed, and preferably means are provided to influence, in particular to control and / or regulate, the hardness of the resulting roll in a predetermined manner when the tissue web is being wound up.

Preferred embodiments of the tissue machine according to the invention are specified in the subclaims.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the drawing, in which:

Figure 1 is a schematic representation of an example

Embodiment of the tissue machine according to the invention,

Figure 2 is a schematic representation of an example

Embodiment of the headbox of the tissue machine according to the invention,

FIG. 3 shows a schematic partial illustration of a crepe doctor assigned to the drying cylinder of the tissue machine according to the invention, Figure 4 is a schematic representation of a conventional

Tissue winder,

FIG. 5 shows a schematic illustration of an exemplary embodiment of a winding device according to the invention of the tissue machine according to the invention with a displaceable, path-controlled drum or winding roll,

FIG. 6 shows a schematic representation of a further embodiment of the winding device according to the invention of the tissue machine according to the invention with a movable drum or winding roll with associated pressure and / or force sensors,

Figure 7 is a diagram showing the influence of the line force in the

Reproduces the winding gap to the specific volume (bulk) of the tissue web in the winding roll,

FIG. 8 shows a diagram which, in comparison to a suction press roll (SPR), shows the influence of a shoe press (TF) according to the invention on the specific volume (bulk) as a function of the linear force of the press, a so-called "T-" from 90 kN / m. Rib "- Yankee cylinder, ie a Yankee cylinder with inner reinforcing ribs is used,

FIG. 9 shows a diagram comparable to the diagram in FIG. 8, but in this case for the "hand feel", FIG. 10 shows a diagram comparable to the diagram in FIG. 8, but in this case for the dry content after the press,

FIG. 11 shows a diagram which shows the influence of drying conditions, in particular the Yankee cylinder / drying hood drying ratio,

Figure 12 is a graph showing the influence of the thickness of the creping doctor on the thickness of the tissue paper (bulk), and

FIG. 13 shows a diagram which shows the influence of the multi-layer production of the tissue paper on the specific volume (bulk) in the case of different presses, in particular the advantage resulting from the use of a shoe press (TF) compared to a suction press roll (SPW).

FIG. 1 shows a schematic illustration of an exemplary embodiment of a machine 10 according to the invention for producing a tissue web 12.

The tissue machine 10 comprises a headbox 14 and an endless carrier belt 16, with which the tissue web 12 is guided through a press nip 22 formed between a drying cylinder 18, here a Yankee cylinder 18, and a counter unit 20. The tissue machine 10 also comprises a winding device (roller apparatus) 24 for the subsequent winding of the tissue web 12.

A multi-layer headbox, in the present case a two-layer headbox, is provided as the headbox 14, to which at least two different types of material can be fed.

In addition, means described in more detail below are provided in order to influence the hardness of the resulting winding in a predeterminable manner when winding the tissue web 12, i.e. in particular to control and / or regulate. The line force generated in the winding gap 26 is preferably kept less than or equal to 0.8 kN / m. A former having two circulating endless belts 16, 28 is provided, one of these two endless circulating belts 16, 28 simultaneously forming the conveyor belt 16.

As can be seen from FIG. 1, the two endless belts 16, 28 converge to form a material inlet gap 30 in order to then be guided over a forming element 32, in particular a forming or breast roll. The wrap angle with respect to the outer band 28 is smaller than that with respect to the inner carrier band 16.

In the present case, a crescent former is provided, the inner band (carrier band) 16 of which is formed by a felt band.

In the inlet gap 30 formed between the carrier tape 16 and the outer screen 28, different types of material, in the present case a type of material HW of Fa- hardwood and a fabric type SW of fibers from softwood. The hardwood fibers can in particular be short fiber pulps and the soft wood fibers can be long fiber pulps in particular.

The tissue web that is formed is fed to the press nip 22, which is extended in the web running direction L, after the wrapping area of the forming roller 32 together with the carrier tape 16.

Before reaching the extended press nip 22, the carrier web 16 carrying the tissue web 12 wraps around a suction device designed here as a suction roller 34. The suction roller 34 removes a substantial part of the water from the carrier tape 16 and even somewhat from the outer tissue web 12.

The counter unit 20 assigned to the drying cylinder 18 is formed in the present case by a shoe press unit, in particular a shoe press roller. The press nip 22 is therefore the extended press nip of a shoe press comprising the drying cylinder 18 and the shoe press unit 20.

The drying cylinder 18 is associated with a particularly thin crepe scraper or bar 36.

Following the press nip 22, the tissue web 12 is guided around the drying cylinder 18. In this case, a drying hood 38 is provided in order to intensify the drying in the relevant wrapping area. As can be seen from FIG. 1, a measuring frame 39 is provided between the drying cylinder 18 and the winding device 24. The measured values obtained can, for. B. can also be used for a cross profile control of certain web properties.

In the winding device 24, the tissue web 12 is first passed over a carrying drum 40 and then wound onto a reel 42. A separate drive 44 is preferably assigned to both the carrying drum 40 and the drum 42.

As can be seen from FIG. 1, the fabric type HW of short fibers obtained from hardwood is used for the layer Y facing the surface of the drying cylinder 18 and the fabric type of long fibers obtained from softwood is used for the layer provided on the opposite side of the web.

Figure 2 shows a schematic representation of an exemplary embodiment of the headbox 14 of the tissue machine according to the invention. The nozzle 46 of this headbox 14 is at least essentially divided into two channels 50, 52 by a lamella 48 which extends over the entire width of the machine. The lamella 48 extends in the area of the outlet gap 54 beyond the nozzle 46 to the outside. The amount of fins h measured from the turbulence generator 56 of the headbox 14, like the nozzle length h, is thus greater than the nozzle length

In Figure 2, the cross manifolds 58, 60 can also be seen for the two types of fabric. In the present case, moreover, only for the layer facing the forming roller 32 (cf. FIG. 1) is a dilution water control and / or control sectioned across the machine width. In Figure 2, a cross manifold 61 for z. B. to recognize dilution water.

One or more orifices 62 can be provided in the area of the outlet gap 54 of the nozzle 46. However, such panels are not mandatory.

The proportion of drying contributed by the drying hood 38 to dry the tissue web 12 is preferably greater than the proportion of drying contributed by the drying cylinder 18.

FIG. 3 shows a schematic partial representation of a crepe scraper 36 assigned to the drying cylinder or Yankee cylinder 18 of the tissue machine 10 according to the invention (see FIG. 1).

In the present exemplary embodiment shown in FIG. 3, the thickness b of the creping doctor 36 is less than or equal to 0.9 mm. The angle of attack or clearance between the tangent 76 through the point of contact 78 to the drying cylinder 18 and the creping scraper 36 is less than or equal to 20 °. The "rake angle" of the creping scraper 36, designated "β" in FIG. 3, can in particular be greater than or equal to 15 °.

FIG. 4 shows a schematic representation of a conventional winding device 64 for tissue, in which the carrying drum 68 provided with a drive 66 is pressed against the winding roller 70 on which the tissue web produced is wound, whereby the winding roller 70 is driven. The carrying drum 68 is stationary. The winding roll 70 is on slide NEN 72 movable. The contact pressure must be large enough to transmit the required drive power. The line force generated in the winding gap 74 is 0.8 kN / m (width). The line force is so great that the support drum 68 dips into the soft winding roll 70 and thus destroys or reduces the specific volume (bulk). The increase in diameter of the winding roller 70 is taken into account by moving the winding roller 70 away from the carrying drum 68.

FIGS. 5 and 6 show a schematic illustration of two exemplary embodiments of the winding device 24 according to the invention.

In the respective winding device 24, the tissue web 12 is guided over a carrying drum 40 and then wound onto a reel 42. In both embodiments, both the carrying drum 40 and the drum 42 are each assigned a drive 44.

A winding gap or contact nip 26 is formed between the winding or winding roll 80 forming on the reel 42 and the carrying drum 40, in which a line force is generated which corresponds to the resulting one

Winding hardness significantly influenced. At least the drum 42 is in the x direction, i.e. for example horizontally, movable along rails 82 or the like.

The embodiment of the winding device 24 shown in FIG. 6 is an example of a possible solution for the regulation of the line force.

In the present case, the carrying drum 40 is fixedly mounted on the rails 82. In contrast, the drum 42 and accordingly the one on it formed winding roll 80 movable or movable. The position of the drum 42 can be changed, for example, by translational actuators provided on both sides, such as threaded rods with an associated motor, hydraulic cylinder, etc.

Preferred criteria for the displacement or displacement of the spool 42 or the roll 80 formed thereon are the increase in the roll diameter D and the line force in the roll gap 26.

In this embodiment, both criteria can be met with a control loop.

Sensors 83 can be integrated in the bearings of the spool 42, which measure the nip force F in the area of the press nip or press nip 26 directly or indirectly. The sensors mentioned can be, for example, pressure sensors, force sensors, strain gauges, etc.

For example, does the measured force deviate from the specified force, i.e. a corresponding setpoint, the pressure, for example of a relevant hydraulic cylinder, e.g. via a hydraulic unit, changed so that the difference between the setpoint and the measured value becomes "zero".

Such a modification of this embodiment is of course also conceivable, in which only the carrying drum 40 or both the carrying drum 40 and the drum 42 can be moved or displaced. In the case of a movable support drum 40, this has the relevant sensors, via which the nip force F is regulated. In this case, the winding roll displacement only compensates for the increase in the winding diameter D.

The distance between the axes of the carrying drum 40 and the reel 42 or the winding roll 80, which increases increasingly during the winding process, is designated by "A" in FIG.

With smaller line forces and large, heavy winding rolls, it may happen that the measuring accuracy of the sensors and the setting accuracy (friction) are no longer sufficient.

Particularly in the case of line forces in the winding gap 26 which are less than or equal to 0.5 kN / m and in particular less than or equal to 0.2 kN / m, for example the movable drum and correspondingly the winding roller 80 formed therefrom is preferably designed to be path-controlled. The embodiment shown in FIG. 5 is a corresponding embodiment.

The following variables in particular are provided as measured variables for this path control:

Diameter D of the winding roll 80

Position of the winding roll 80 or the reel 42 relative to the carrying drum 40.

The position of the winding roll 80 can be measured, for example, by sensors such as LVDTs (Linear Variable Differential Transformer) and the diameter of the winding roll can be determined, for example optically or acoustically, using a distance sensor. The actuators 86 (see FIG. 6) which can be, for example, hydraulic cylinders, etc., position the winding roller 80 in such a way that it just touches the carrier drum 40, for example. In this case, the line force FL generated in the winding gap 26 is zero. If F _L > 0 kN / m, the winding roller 80 can be moved further towards the carrying drum 40 in a predeterminable way, which depends in particular on the softness of the winding roller 80. This creates a slight desired pressure in the press nip or contact nip 26 of, for example, FL <0.2 kN / m. The distance A (cf. also FIG. 6) is therefore A <d / 2 + D / 2 or A = d / 2 + D / 2 - x, where "x" is the measure of how far the carrying drum 40 is in the immersed on the reel 42 formed roll 80.

Another option for checking and adjusting the nip force is obtained, for example, by observing the nip area with a CCD camera. In particular, the distance between the carrying drum 40 and the winding roll 80 can thus be measured and displayed. Using a corresponding evaluation of the image obtained, a setpoint can then be calculated again, for example for a hydraulic cylinder pressure, and the control can be used to effect the displacement up to the desired distance or nip force. The bulk profit is in the range of 4 to 8%.

To illustrate the path control, a pointer 88 is assigned to the drum 42 in the illustration according to FIG. 5, the position of said pointer 88 with respect to a stationary scale 90 ultimately indicating the position of the drum 42 and thus of the roll 80 formed thereon. In addition, a sensor 92 can be seen in FIG. 5, which is, in particular, a sensor of the aforementioned type, e.g. B. can only act a CCD camera or the like.

FIG. 7 shows a diagram which shows the influence of the line force LF in the winding gap on the specific volume (bulk) of the tissue web in the winding roll. "HW" is a type of material made of hardwood fibers and "SW" is a type of material made of soft wood fibers.

Figure 8 shows a diagram compared to a suction press roll

(SPR) reflects the influence of a shoe press (TF) provided according to the invention on the specific volume (bulk) as a function of the line force of the press. From 90 kN / m a so-called "T-Rib" Yankee cylinder, i.e. a Yankee cylinder with inner reinforcing ribs is used.

FIG. 9 shows a diagram comparable to the diagram in FIG. 8, but in this case for the “hand feel” already mentioned at the beginning.

FIG. 10 also shows a diagram comparable to the diagram in FIG. 8, but in this case for the dry content after the press.

The diagram in FIG. 11 shows the influence of drying conditions, in particular the Yankee cylinder / drying hood drying ratio.

The diagram in FIG. 12 shows the influence of the thickness of the creping doctor on the thickness of the tissue paper, which here is the specific volume (bulk) corresponds. On the other hand, an improved "handfeel" value with a constant "bulk" value is also possible. In the diagram, the abbreviation "GMT" stands for the English expression "geometric mean tensile" (geometric mean value of the strength).

FIG. 13 shows a diagram which shows the influence of the multi-layer production of the tissue paper on the specific volume (bulk) in the case of different presses, in particular the advantage resulting from the use of a shoe press (TF) compared to a suction press roll (SPW) ,

LIST OF REFERENCE NUMBERS

Tissue machine Tissue web headbox endless circulating belt, carrier belt drying cylinder, Yankee cylinder counter unit, shoe press unit press nip, contact nip winding device, winding device, rolling device winding nip endless circulating belt, outer sieve material inlet nip forming element, forming roller, breast roller vacuumed device, drying roller scraper drum channel 52 channel

54 outlet gap

56 turbulence generators

58 Cross distributor pipe

60 cross distributor pipe

61 Cross distributor pipe

62 aperture

64 winding device, trolley

66 drive

68 carrying drum

70 winding roll

72 rails

74 winding nip

76 tangent

78 point of contact

80 reels, winding reel

82 rails

83 sensor

84 controllers

86 actuator

88 hands

90 scale

92 sensor

A distance

D winding diameter

F nip force, force in the winding gap b thickness

nozzle length h slat length

α Angle of attack, clearance angle ß "Span winke!"

Claims

Patent claims

1. A method for producing a tissue web (12) by means of a tissue machine (10) with a headbox (14) and an endless carrier belt (16) with which the tissue web (12) passes through a between a drying cylinder (18) and a counter unit (20 ) formed press nip (22), a multi-layer headbox (14) being used as the headbox, at least two types of material being fed to this multi-layer headbox (14) and the tissue web (12) following the press nip (22) by means of a winding device ( 24) is wound up, the hardness of the resulting roll (80) preferably being influenced, in particular controlled and / or regulated, in a predeterminable manner.

2. The method according to claim 1, characterized in that a Yankee cylinder is used as the drying cylinder (18).

3. The method according to claim 1 or 2, characterized in that the line force generated in the winding gap (26) is selected to be less than or equal to 0.8 kN / m.

4. The method according to any one of the preceding claims, characterized in that a former with two circulating endless belts (16, 28) is used, which converge to form a stock inlet gap (30) and is then passed over a forming element (32), such as in particular a forming roller, preferably with the forming element (32) in Contacting inner belt forms the conveyor belt (16).

5. The method according to any one of the preceding claims, characterized in that a crescent former is used, the inner band (16) of which is formed by a felt band.

6. The method according to any one of the preceding claims, characterized in that the tissue web (12) is guided together with the carrier tape (16) through at least one shoe press (18, 20).

7. The method according to claim 6, characterized in that a shoe press unit is used as the counter unit (20) assigned to the drying cylinder (18).

8. The method according to any one of the preceding claims, characterized in that the tissue web is scraped off the drying cylinder by means of a particularly thin crepe scraper.

9. The method according to any one of the preceding claims, characterized in that one or more of the following types of substance are used: - Hardwood fibers, especially short fiber pulps

- Fibers from softwood, especially long-fiber pulps

- CTMP (Chemical-thermo-mechanical pulp).

10. The method according to any one of the preceding claims, characterized in that a material type mixture is used in which the proportion of fibers made of hardwood is in a range from approximately 50% to approximately 80%.

11. The method according to any one of the preceding claims, characterized in that a mixture of fabrics is used in which the proportion of fibers from softwood is in a range from about 20% to about 50

% lies.

12. The method according to any one of the preceding claims, characterized in that a mixture of substances is used in which the proportion of CTMP (Chemical-thermo-mechanical Pulp) is in a range from 0% to about 20%.

13. The method according to any one of the preceding claims, characterized in that the tissue web (12) is guided after the press nip (22) around the drying cylinder (18), the drying in the relevant wrapping area preferably also by means of a drying hood (38) is reinforced.

14. The method according to any one of the preceding claims, characterized in that the multilayer headbox (14) are supplied with at least two different types of material and thereby for the layer of the tissue web (12) facing the drying cylinder surface, short fibers obtained from hardwood and for the layer provided on the opposite side of the web Long fibers obtained from softwood can be used.

15. The method according to claim 14, characterized in that CTMP (chemical-thermo-mechanical pulp) is additionally used for the layer provided on the opposite web side.

16. The method according to claim 15, characterized in that short fibers are additionally used for the layer provided on the opposite web side.

17. The method according to any one of the preceding claims, characterized in that a multi-layer headbox (14) is used, the nozzle (46) is divided into at least two channels (50, 52) by at least one lamella (48) extending over the entire machine width ,

18. The method according to claim 17, characterized in that that the nozzle (46) is at least substantially symmetrically divided into two channels (50, 52) by a lamella (48).

19. The method according to claim 17 or 18, characterized in that the lamella (48) extends outward in the region of the outlet gap (54) beyond the nozzle (46).

20. The method according to any one of the preceding claims, characterized in that a multi-layer headbox (14) is used with a dilution water control and / or control that is sectional across the machine width.

21. The method according to claim 20, characterized in that a dilution water control and / or control that is sectional across the machine width is provided for at least two layers.

22. The method according to claim 20 or 21, characterized in that a dilution water control and / or control is provided at least for the layer facing the forming roller (32).

23. The method according to any one of the preceding claims, characterized in that the drying hood (38) for drying the tissue web (12) contributed drying proportion greater than the drying proportion contributed by the drying cylinder (18).

24. The method according to claim 23, characterized in that the ratio between the drying proportion of the drying hood (38) and the drying proportion of the drying cylinder (18) is greater than 55:45, in particular greater than or equal to 60:30, in particular greater than or equal to 65:35 and preferably greater than or equal to 70:30 is chosen.

25. The method according to any one of the preceding claims, characterized in that the drying hood (38) is operated at a temperature which is greater than or equal to 400 ° C, in particular greater than or equal to 500 ° C, in particular greater than or equal to 600 ° C and preferably greater o- which is equal to 700 ° C.

26. The method according to any one of the preceding claims, characterized in that a value is selected for the vapor pressure in the drying cylinder (18) that is less than or equal to 0.7 MPa, in particular less than or equal to 0.6 MPa and preferably less than or equal to 0, Is 5 MPa.

27. The method according to any one of the preceding claims, characterized in that a winding device (24) is used in which the tissue web (12) is guided over a carrying drum (40) and then wound onto a spool (42), preferably a drive (44) is assigned to both the carrying drum (40) and the drum (42).

28. The method according to claim 27, characterized in that the line force generated in the winding gap (26) between the support drum (40) and the drum (42) is less than or equal to 0.8 kN / m, in particular less than or equal to 0.5 kN / m and preferably less than or equal to 0.2 kN / m is selected.

29. The method according to claim 27 or 28, characterized in that the maximum difference between the peripheral speed of the winding (80) and the peripheral speed of the carrier drum (40) is less than 10% of the peripheral speed of the carrier drum (40).

30. The method according to any one of the preceding claims, characterized in that the web tension between the drying cylinder (18) and the carrier drum (40) via the drive (44) assigned to the carrier drum (40) independently of the line force generated in the winding gap (26) a predefinable target value is set, in particular controlled and / or regulated.

31. The method according to any one of the preceding claims, characterized in that the drive (44) assigned to the drum (42) is controlled and / or regulated as a function of the speed of the carrying drum (40).

32. Method according to one of the preceding claims, characterized in that the carrying drum (40) is mounted in a stationary manner and the drum (42) can be moved.

33. The method according to claim 32, characterized in that the increase in the winding diameter (D) is compensated for by a corresponding method of the spool (42).

34. The method according to claim 32 or 33, characterized in that the line force in the winding gap (26) is set via the movable drum (42).

35. The method according to any one of the preceding claims, characterized in that a common control loop is used to compensate for the increase in winding diameter and to adjust the line force in the winding gap (26).

36. Method according to one of the preceding claims, characterized in that the line force in the winding gap (26) is determined via at least one force sensor and this line force is regulated by a corresponding method of the spool (42).

37. The method according to any one of the preceding claims, characterized in that that in particular in the case of line forces in the winding gap (26) which are less than or equal to 0.5 kN / m and in particular less than or equal to 0.2 kN / m, the movable drum (42) is path-controlled.

38. The method according to claim 37, characterized in that the winding diameter (D) and the position of the reel (42) or the winding (80) formed thereon are used for the displacement control as measured variables relative to the carrying drum (40).

39. Method according to one of the preceding claims, characterized in that the position of the winding roll (80) is measured in particular by sensors such as LVDTs (Linear Variable Differential Transformer) or the like.

40. Method according to one of the preceding claims, characterized in that the area of the winding gap (26) is monitored accordingly by means of a CCD camera for setting or controlling and / or regulating the line force in the winding gap (26).

41. The method according to claim 40, characterized in that the respective distance (A) between the carrying drum (40) and the drum (42) or the roll (80) formed thereon is detected by means of the CCD camera.

42. The method according to any one of the preceding claims, characterized in that that the drive assigned to the drum is not changed during the winding process.

43. The method according to any one of the preceding claims, characterized in that the area-related mass of the tissue web (12) in the uncreped state in a range from about 11 g / m ² to about 20 g / m ² and in the creped state in a range from about 14 g / m ² to about 24 g / m ² .

44. The method according to any one of the preceding claims, characterized in that a crescent former is used, the inner or carrier band (16) formed by a felt band together with the tissue web (12) in the web running direction (L) in front of the press nip (22 ) is guided over at least one suctioned device (34).

45. The method according to claim 44, characterized in that the evacuated device comprises a suction roller (34).

46. Method according to one of the preceding claims, characterized in that the outer belt provided in the area of the forming element (32) of the crescent former is formed by a sieve belt (28).

47. Method according to one of the preceding claims, characterized in that a shoe press (18, 20) with a web running direction (L) measured shoe length greater than or equal to 80 mm and preferably greater than or equal to 120 mm is used.

48. Method according to one of the preceding claims, characterized in that a line force is generated by means of the shoe press (18, 20) which is in a range from approximately 60 kN / m to approximately 90 kN / m.

49. Method according to one of the preceding claims, characterized in that the maximum pressing pressure in the press nip of the shoe press (18, 20) is chosen to be less than or equal to 2 bar and preferably less than or equal to 1.5 bar.

50. Method according to one of the preceding claims, characterized in that the shoe press (18, 20) comprises a shoe press unit (20) with a blind-drilled press jacket.

51. Method according to one of the preceding claims, characterized in that a drying cylinder or Yankee cylinder (18) provided inside with reinforcing ribs is used.

52. The method according to any one of the preceding claims, characterized in that the thickness (b) of the creping doctor (36) is less than or equal to 0.9 mm.

53. Method according to one of the preceding claims, characterized in that the angle of attack (α) between the tangent (76) to the drying cylinder (18) and the creping doctor (36) is less than or equal to 20 °.

54. The method according to any one of the preceding claims, characterized in that the rake angle (β) of the creping doctor (36) is greater than or equal to 15 °.

55. Machine (10) for producing a tissue web (12), in particular for carrying out the method according to one of the preceding claims, with a headbox (14) and an endless carrier tape (16) with which the tissue web (12) through a between a Drying cylinder (18) and a counter-unit (20) formed press nip (22) is guided, as well as with a winding device (24) for subsequent winding of the tissue web (12), wherein a multi-layer headbox is provided as the headbox (14), to which at least two types of material can be fed are, and preferably means (84, 86, 92) are provided in order to influence, in particular to control and / or regulate, the hardness of the resulting roll (80) in a predeterminable manner when the tissue web (12) is being wound up.

56. Machine according to claim 55, characterized in that a Yankee cylinder is provided as the drying cylinder (18).

57. Machine according to claim 55 or 56, characterized in that that the line force generated in the winding gap (26) is less than or equal to 0.8 kN / m.

58. Machine according to one of the preceding claims, characterized in that a former with two circulating endless belts (16, 28) is provided, which converge to form a material inlet gap (30) and then guided over a forming element (32), such as in particular a forming roller are, wherein preferably the inner belt coming into contact with the forming element (32) forms the conveyor belt (16).

59. Machine according to one of the preceding claims, characterized in that a crescent former is provided, the inner band (16) of which is formed by a felt band.

60. Machine according to one of the preceding claims, characterized in that the tissue web (12) together with the carrier tape (16) is guided through at least one shoe press (18, 20).

61. Machine according to claim 60, characterized in that the counter unit (20) assigned to the drying cylinder (18) is formed by a shoe press unit.

62. Machine according to one of the preceding claims, characterized in that that in particular a thin crepe doctor (36) is associated with the drying cylinder (18).

63. Machine according to one of the preceding claims, characterized in that the tissue web (12) is guided around the drying cylinder (18) following the press nip (22), a drying hood (38) preferably being used to reinforce the drying in the relevant wrapping area. is provided.

64. Machine according to one of the preceding claims, characterized in that the nozzle (46) of the multi-layer headbox (14) is divided into at least two channels (50, 52) by at least one lamella (48) extending over the entire machine width.

65. Machine according to claim 62, characterized in that the nozzle (46) is at least substantially symmetrically divided into two channels (50, 52) by a lamella (48).

66. Machine according to claim 64 or 65, characterized in that the lamella (48) extends outward in the region of the outlet gap (54) beyond the nozzle (46).

67. Machine according to one of the preceding claims, characterized in that the multi-layer headbox (14) with a via the machine broad sectional dilution water control and / or control.

68. Machine according to claim 67, characterized in that a dilution water control and / or control that is sectional across the machine width is provided for at least two layers.

69. Machine according to claim 67 or 68, characterized in that a dilution water control and / or control is provided at least for the layer facing the forming roller (32).

70. Machine according to one of the preceding claims, characterized in that the drying proportion contributed by the drying hood (38) for drying the tissue web (12) is greater than the drying proportion contributed by the drying cylinder (18).

71. Machine according to claim 70, characterized in that the ratio between the drying proportion of the drying hood (38) and the drying proportion of the drying cylinder (18) is greater than 55:45, in particular greater than or equal to 60:30, in particular greater than or equal to 65:35 and is preferably greater than or equal to 70:30.

72. Machine according to one of the preceding claims, characterized in that the drying hood (38) can be operated at a temperature which is greater than or equal to 400 ° C, in particular greater than or equal to 500 ° C, in particular greater than or equal to 600 ° C and preferably greater o- which is equal to 700 ° C.

73. Machine according to one of the preceding claims, characterized in that the steam pressure in the drying cylinder (18) is less than or equal to 0.7 MPa, in particular less than or equal to 0.6 MPa and preferably less than or equal to 0.5 MPa.

74. Machine according to one of the preceding claims, characterized in that the tissue web (12) in the winding device (24) is guided over a carrying drum (40) and is then wound onto a spool (42), preferably both the carrying drum (40) and the drum (42) each have a drive (44) assigned to them.

75. Machine according to claim 74, characterized in that the line force generated in the winding gap (26) between the carrying drum (40) and the reel (42) is less than or equal to 0.8 kN / m, in particular less than or equal to 0.5 kN / m and preferably less than or equal to 0.2 kN / m.

76. Machine according to claim 74 or 75, characterized in that that the maximum difference between the peripheral speed of the winding (80) and the peripheral speed of the support drum (40) is less than 10% of the peripheral speed of the support drum (40).

77. Machine according to one of the preceding claims, characterized in that the web tension between the drying cylinder (18) and the support drum (40) via the drive (40) associated with the drive (44) independently of the line force generated in the winding gap (26) a predefinable setpoint is adjustable, in particular controllable and / or regulatable.

78. Machine according to one of the preceding claims, characterized in that the drive (44) assigned to the drum (42) can be controlled and / or regulated depending on the speed of the carrying drum (40).

79. Machine according to one of the preceding claims, characterized in that the carrying drum (40) is mounted in a stationary manner and the drum (42) can be moved.

80. Machine according to claim 79, characterized in that means (84, 86, 92) are provided in order to automatically compensate for the increase in the winding diameter (D) by a corresponding method of the spool (42).

81. Machine according to claim 79 or 80, characterized in that means (84, 86, 92) are provided in order to automatically adjust the line force in the winding gap (26) accordingly via the movable drum (42).

82. Machine according to one of the preceding claims, characterized in that a common control loop is provided to compensate for the increase in winding diameter and to adjust the line force in the winding gap (26).

83. Machine according to one of the preceding claims, characterized in that at least one force sensor is provided to determine the line force in the winding gap (26) and that the line force can be regulated by a corresponding method of the spool (42).

84. Machine according to one of the preceding claims, characterized in that, in particular with linear forces in the winding gap (26) which are less than or equal to 0.5 kN / m and in particular less than or equal to 0.2 kN / m, the movable drum (42 ) is steered.

85. Machine according to one of the preceding claims, characterized in that the winding diameter (D) and the position of the reel (42) or the winding (80) formed thereon are used for the displacement control as measured variables relative to the carrying drum (40).

86. Machine according to one of the preceding claims, characterized in that sensors such as, in particular, LVDTs (linear variable differential transformers) or the like are provided in order to measure the position of the winding roll (30).

87. Machine according to one of the preceding claims, characterized in that the area of the winding gap (26) can be appropriately monitored by means of a CCD camera for setting or controlling and / or regulating the line force in the winding gap (26).

88. Machine according to claim 87, characterized in that the respective distance (A) between the carrying drum (40) and the drum (42) or the roll (80) formed thereon can be detected by means of the CCD camera.

89. Machine according to one of the preceding claims, characterized in that the inner or carrier band (16) of the crescent former formed by a felt band together with the tissue web (12) in the web running direction (L) in front of the press nip (22) over at least a suction device (34) is guided.

90. Machine according to claim 89, characterized in that the suction device comprises a suction roller (34).

91. Machine according to one of the preceding claims, characterized in that the outer belt provided in the area of the forming element (32) of the crescent former is formed by a sieve belt (28).

92. Machine according to one of the preceding claims, characterized in that the shoe press (18, 20) has a shoe length measured in the web running direction (L) which is greater than or equal to 80 mm and preferably greater than or equal to 120 mm.

93. Machine according to one of the preceding claims, characterized in that the line force generated by the shoe press (18, 20) is in a range from approximately 60 kN / m to approximately 90 kN / m.

94. Machine according to one of the preceding claims, characterized in that the maximum pressing pressure in the press nip of the shoe press (18, 20) is less than or equal to 2 bar and preferably less than or equal to 1.5 bar.

95. Machine according to one of the preceding claims, characterized in that the shoe press (18, 20) comprises a shoe press unit (20) with a blind-drilled press jacket.

96. Machine according to one of the preceding claims, characterized in that that the drying cylinder or Yankee cylinder (18) is provided with reinforcing ribs on the inside.

97. Machine according to one of the preceding claims, characterized in that the thickness (b) of the creping doctor (36) is less than or equal to 0.9 mm.

98. Machine according to one of the preceding claims, characterized in that the angle of attack (α) between the tangent (76) to the drying cylinder (18) and the creping doctor (36) is less than or equal to 20 °.

99. Machine according to one of the preceding claims, characterized in that the rake angle (β) of the creping doctor (36) is greater than or equal to 15 °.