EP1016754A1 - Machine and method for the manufacture of a fibrous web - Google Patents

Abstract

The papermaking machine, especially for tissue or toilet paper, has at least one press gap (12) between a shoe press unit (14) and the drying/tissue cylinder (16). The length (L) of the press gap is ≤ 60 mm, in the direction (l) of web travel. The pressure profile along the length (L) of the press gap (12) has a max. pressure of ≥ 3.3 MPa. The press gap length (L) is pref. ≤ 50 mm, and the max. pressure is 4.8 MPa within a press gap length stretch of 37 mm. To form a tissue paper web, the angle between the tangent at the end of the press gap (12) at the drying cylinder (16) and the carrier blanket (18) leaving the press gap (12) is ≥ 10 degrees and especially ≥ 18 degrees and pref. ≥ 20 degrees . The press blanket (20) is ridged and/or is fitted with blind drillings. The length (L) of the press gap (12) can be ≥ 80 mm and pref. less than 200 mm and especially a max. of 150 mm. The max. pressure in the pressure profile is ≤ 2 MPa. The max. linear pressure applied in the press gap (12) is 90-110 kN/m and/or the shoe press unit (14) has a press shoe (22) with a number of independent press components (26) across the direction (l) of web travel, to be pressed against the drying cylinder. The drying cylinder (16) is a Yankee cylinder and/or has an asymmetrical pressure profile along the length (L) of the press gap. The max. pressure is applied in the trailing one-half or one-quarter of the press gap length (L), in the direction (l) of web travel. The mean pressure rise gradient from the start of the press gap to the max. pressure zone, with a carrier blanket of a new value, is ≥ 40 kPa/mm and especially ≥ 60 kPa/mm and pref. ≥ 120 kPa/mm and/or the mean pressure drop gradient at the end of the press gap with a new value carrier blanket is ≥ 300 kPa/mm and especially ≥ 500 kPa/mm and pref. ≥ 800 kPa/mm or ≥ 800 kPa/mm or ≥ 960 kPa/mm and/or the water-absorbent blanket (18) in the press gap (12) lies between the impermeable press blanket (20) and the web with the web in contact with the drying cylinder (16) and/or a felt blanket is used for the water-absorbent carrier (18). The water-absorbent carrier blanket (18) has different qualities through its thickness, with a finer structure at the side towards the web than at the other side. The press blanket (20) has a surface which is smooth, ridged and/or with blind drillings and/or at least one additional press gap (12) is formed at the drying cylinder (16) using two shoe press units (14). A further press gap (12) is formed before the drying cylinder (16), in the direction (l) of web travel and/or the carrier blanket (18) and the web pass through at least one preceding suction unit. The suction unit has a suction roller and/or a suction shoe and/or it is a shoe press roller where the press blanket is pref. formed by the press mantle (20) of the shoe press roller (14). The shoe press unit (14) has at least one replaceable press shoe (22) and/or the carrier blanket is structured to give an imprint or patterning. An Independent claim is included for tissue-toilet paper prodn., where the wet fiber web is within the press gap (12) for a time span of max. 3 ms at a pressure of at least 3.3 MPa or at least 3.5 ms at a max. pressure of 2 MPa.

Description

The invention relates to a machine for producing a fibrous web, in particular tissue or tissue paper web, with at least one between a shoe press unit and a drying or tissue cylinder formed press nip through which a water-absorbing carrier tape waterproof press tape and the fibrous web passed through are. It also relates to a method for producing a fibrous web 31 according to the preamble of claims 30 and 31.

DE-A-42 24 730 describes several embodiments of a machine of the type mentioned above. This includes all embodiments at least two press nips are provided. In the When viewed in the direction of web travel, the main press located at the rear comprises each a drying cylinder and an associated pressure element. As such Pressure element can be a suction press roll or a shoe press roll his.

Even in a machine known from DE-A-196 54 197 of the beginning mentioned type two press nips are again provided. The back the main press lies through a shoe press unit and a drying cylinder educated.

In the known machines there are therefore always two or more press nips intended. This is considered imperative here on the one hand, particularly in the manufacture of a tissue or hygiene paper web required gentle drainage without pressing and on the other hand, an improved production performance through an increased To achieve dryness after the press. This is done with the full or partial replacement of the nip presses with shoe presses due to the corresponding gap extension or increase in the pressing time gentle drainage of the web achieved without squeezing.

A major disadvantage of these known designs now exists but in the relatively high investment and operating costs compared to the improvements achieved. In view of the usual limit the maximum line force to a value in the range of 90 kN e.g. For Yankee cylinders, it was always necessary with the known press concepts to provide at least two press nips.

The aim of the invention is to provide a machine and a method to create the kind mentioned, avoiding the aforementioned Disadvantages as well as largely adhering to those for the produced The highest possible level of dryness as required by the railway and / or specific volume can be achieved.

In a dewatering press described in EP-A2-0 852 273 the production of a paper and / or cardboard web serving machine is the dwell time of the web in an extended press nip less than 12 ms.

With regard to the machine, this object is achieved according to the invention solved that at least one between a shoe press unit and Drying or tissue cylinder formed press nip is provided, the Length considered in the direction of web travel or equal to a value of is about 60 mm and its resulting over the press nip length Pressure profile has a maximum pressure that is greater than or equal to is about 3.3 MPa.

With such training, a significant increase is unexpectedly both the dry matter content and the specific volume the fibrous web is reached. This is all the more surprising than with the proposed solution of the one currently used in press development Is left way, the goal of which was to replace the nip presses by shoe presses with extended Press nip gentle, slow dewatering as a prerequisite for to achieve optimal results. Because of the training according to the invention can now, for example, use many tissue paper machines only a single shoe press nip can be realized.

In a preferred practical embodiment of the invention Machine is the press nip length of mine or a value of about 50 mm and the maximum pressing pressure greater than or equal to a value of about 4.3 MPa. The nip length is as the touched length between Drying cylinder and assigned pressure element and continuous new carrier tape defined.

Here, the specific volume is also increased slightly. Such The increase can be about 5%, for example. A significant one There is an increase in dry matter, which is particularly true in Comparison to a press nip applies by means of a suction press roll or by a shoe press with a gap length of, for example, 120 mm is formed. In this case, for example, there is an increase in dry matter possible by about 2.5 to 3% if of a constant line force 90 kN / m is assumed. Such a value may be the previously common Yankee cylinders given a maximum allowable mechanical stress must not be exceeded. The invention is therefore particularly useful when converting existing presses can be used with particular advantage. So compared to the conventional Presses despite a respective line force limit, increase in dry content as well as constant or higher values of the specific volume (Bulk) can be achieved.

In a further expedient embodiment, the press nip length is in a range of about 37 mm and the maximum pressure in one Range of about 4.8 MPa.

In the case of short shoes, it has been shown that the angle between the am Put the end of the press nip on the drying or tissue cylinder Tangent and the carrier tape emerging from the press nip an essential Has an influence on the dry content of the tissue web. An advantageous one Embodiment is characterized in that in particular to make a tissue web this angle between that at the end of the Press nip on the drying or tissue cylinder tangent and the carrier tape emerging from the press nip ≥ 10 °, in particular ≥ 18 ° and preferably ≥ 20 °. This results in applications with suction press rolls an increase in dry content of approx. 1 to 3%. The press belt is preferably grooved and / or blind drilled.

According to an alternative embodiment of the machine according to the invention the aforementioned object is achieved in that at least one between a shoe press unit and the drying or tissue cylinder formed press nip is provided, the one viewed in the web running direction Length greater than a value of about 80 mm and preferably is less than 200 mm, in particular at most 150 mm, and its itself pressure profile resulting over the press nip length a maximum press pressure which is less than or equal to a value of about 2 MPa. It also takes into account the fact that longer shoes, contrary to expectations, the achievable dryness is lower becomes.

In this case in particular, it is advantageous if the dwell time of the Fibrous web in the press nip greater than or equal to a value of, for example is approximately 3.5 ms and in particular is greater than or equal to 4 ms. Here the residence time can be defined in particular by the ratio of Gap or shoe length to the web speed.

The maximum line force generated by the press nip can, for example are in a range from about 90 to about 120 kN / m.

In an expedient practical embodiment of the invention Machine includes the shoe press unit a press shoe that over several pressure elements arranged side by side transversely to the web running direction is pressed against the drying cylinder. With that one can Desired pressing force cross profile to even out the web properties especially at the edges of the web.

A crepe cylinder, i.e. a so-called Yankee cylinders can be provided.

The pressure profile resulting over the press nip length is preferred asymmetrical.

Is the press nip length mine or a value of about 60 mm and the pressure profile has a maximum pressing pressure that is greater or is equal to a value of about 3.3 MPa, the maximum pressure is expediently viewed in the rear half in the direction of web travel the press nip length.

If, on the other hand, the press nip length is greater than a value of approximately 80 mm and the pressure profile has a maximum pressure that is less than or is equal to a value of about 2 MPa, the maximum pressing pressure can especially in the rear quarter of the web viewed in the direction of web travel Press nip length.

Especially with a press nip length that is mine or equal to about 60 mm it is advantageous if the mean pressure rise gradient in the from the beginning of the gap to the maximum pressing section of the Print profile for a new carrier tape greater than or equal to one Value of approximately 40 kPa / mm, in particular greater than or equal to approximately 60 kPa / mm and preferably greater than or equal to about 120 kPa / mm.

The mean pressure drop gradient in the end area of the pressure profile is at a new carrier tape preferably greater than or equal to one Value of approximately 300 kPa / mm, in particular greater than or equal to approximately 500 kPa / mm, and preferably greater than or equal to about 800 kPa / mm. The mean pressure drop gradient in the end area increases with increasing Operating time of the felt too. As a result, in a Press gap values of over 1000 to over 1600 kPa / m reached.

In a preferred practical embodiment, the water absorbent Carrier tape in the press nip between the water impermeable Press belt and the fibrous web, the fibrous web the drying cylinder touched.

In particular, a felt can be provided as the water-absorbing carrier tape. Such a felt can, for example, have a basis weight that is mine or a value of approximately 1450 g / m ² . It is, for example, a felt structured in a special way in the manner of an embossed sieve or felt, that is to say a so-called "imprinting fabric" or "imprinting felt" (see for example WO98 / 00604)) or a "patterning" having a roughly structured surface fabric "or" patterning felt "can be used. The special carrier tapes, in particular in combination with a press nip according to the invention with a press nip length greater than or equal to approximately 80 mm, have an advantageous effect on the specific volume of the paper web produced.

The water-absorbing carrier tape can have a different thickness Exhibit quality. So that facing the fibrous web Side of the carrier tape, for example, have a finer structure as its side facing away from the fibrous web.

In an expedient practical embodiment, the press belt has a grooved and / or blanked surface, as described for example in DE-A-196 54 198.

In principle, a further press nip can also be formed on the drying cylinder his. It can be useful in certain applications be if at least two by means of a respective on the drying cylinder Shoe press unit formed press nips are provided. Basically is it is also conceivable to add an additional one in the web running direction in front of the drying cylinder Provide press nip.

In an expedient practical embodiment of the invention The machine is the carrier tape and the fibrous web in the direction of web travel in front of the drying cylinder via at least one suction device guided, through which a corresponding preliminary drainage then takes place. At least one suction device or Suction box can be provided, the suction roller and / or a suction shoe includes.

In a preferred practical embodiment of the invention A shoe press roll is provided as a shoe press unit.

It is also advantageous if the shoe press unit has at least one replaceable one Press shoe includes.

The method according to the invention in the preamble of claim 30 specified type is characterized in that the drainage Fibrous web in the press nip for a period of at most 3 ms a maximum pressing pressure of the pressure curve of at least 3.3 MPa is exposed. The duration or dwell time of the fibrous web in the press nip defined by the ratio between the nip length and the web speed.

In an alternative embodiment variant of the method according to the invention the type specified in the preamble of claim 31 becomes the draining fibrous web in the press nip for a period of at least 3.5 ms exposed to a pressure of at most 2 MPa.

The invention is applicable, for example, to a crescent former, a four-wire tissue paper machine, a twin wire former, one Suction breast roller machine etc.

The material input for producing a tissue web, for example, can for example, consist of ground material ("refined pulp"). Here can the press nip according to the invention is particularly advantageous for increasing the dry content be used.

This is used, for example, to produce a tissue web Substance can also consist of unground material. In this In this case, the long press nip according to the invention can be used particularly advantageously Increase in specific volume.

The invention can also be used, for example, for so-called "curled fibers". In this case, the stock suspension contains a proportion of fibers, that have been subjected to special treatment. In doing so the essentially straight or curved in one plane pulp fibers so curved that a spatial fiber shape, for example in the manner of a spiral.

The invention is in particular also in a tissue paper machine at least one so-called "through-air-drying" drying process applicable, the press nip according to the invention in particular in front of a corresponding "through-air-drying" device is used. A such a combination is particularly important with regard to a high dry content and a high specific volume is an advantage. By the invention Press nip thus becomes a high dry content on the one hand achieved, thereby reducing the operating costs of the energy-intensive drying phase be reduced. On the other hand, the path becomes marginal at best densifies, which means that the specific volume of the web increases is or remains unaffected at higher pressures, which in particular the "through-air-drying" drying process is also more efficient and becomes more economical.

The invention is particularly also in the production of multilayer Sheets using a single headbox or manufacturing multilayer webs using multiple headboxes applicable.

Figur 1

eine rein schematische Teildarstellung einer erfindungsgemäßen Schuhpresse mit einem zwischen einer Schuhpreßeinheit und einem Trockenzylinder gebildeten Preßspalt,

Figur 2

den Preßdruckverlauf einer herkömmlichen Schuhpresse,

Figur 3

den Preßdruckverlauf einer beispielhaften Ausführungsform der erfindungsgemäßen Schuhpresse mit relativ kurzem Preßschuh,

Figur 4

einen Vergleich des Preßdruckverlaufs einer beispielhaften Ausführungsform der erfindungsgemäßen Schuhpresse mit relativ kurzem Preßschuh mit dem Preßdruckverlauf einer mit einer Saugpreßwalze versehenen herkömmlichen Presse,

Figur 5

einen Vergleich des Preßdruckverlaufs einer beispielhaften Ausführungsform der erfindungsgemäßen Schuhpresse mit relativ langem Preßschuh mit dem Preßdruckverlauf einer mit einer Saugpreßwalze versehenen herkömmlichen Presse,

Figur 6

das spezifische Volumen gegenüber dem Trockengehalt, wobei die für eine beispielhafte Ausführungsform der erfindungsgemäßen Schuhpresse mit relativ kurzem Preßschuh erhaltenen Ergebnisse mit denen für eine mit einer Saugpreßwalze versehenen herkömmlichen Presse verglichen werden,

Figur 7

das spezifische Volumen gegenüber dem Trockengehalt, wobei die für eine beispielhafte Ausführungsform der erfindungsgemäßen Schuhpresse mit relativ langem Preßschuh erhaltenen Ergebnisse mit denen für eine mit einer Saugpreßwalze versehenen herkömmlichen Presse verglichen werden, und

Figur 8

eine rein schematische Teildarstellung einer weiteren Ausführungsform der erfindungsgemäßen Schuhpresse mit einem zwischen einer Schuhpreßeinheit und einem Tissuezylinder gebildeten Preßspalt.

The invention is described below with reference to exemplary embodiments with reference to the drawing; in this show:

Figure 1

2 shows a purely schematic partial representation of a shoe press according to the invention with a press nip formed between a shoe press unit and a drying cylinder,

Figure 2

the pressure pressure curve of a conventional shoe press,

Figure 3

the pressure profile of an exemplary embodiment of the shoe press according to the invention with a relatively short press shoe,

Figure 4

a comparison of the pressure pressure curve of an exemplary embodiment of the shoe press according to the invention with a relatively short press shoe with the pressure pressure curve of a conventional press provided with a suction press roll,

Figure 5

a comparison of the pressure pressure curve of an exemplary embodiment of the shoe press according to the invention with a relatively long press shoe with the pressure pressure curve of a conventional press provided with a suction press roll,

Figure 6

the specific volume compared to the dry content, the results obtained for an exemplary embodiment of the shoe press according to the invention with a relatively short press shoe being compared with those for a conventional press provided with a suction press roll,

Figure 7

the specific volume versus the dry content, the results obtained for an exemplary embodiment of the shoe press according to the invention having a relatively long press shoe being compared with those for a conventional press provided with a suction press roll, and

Figure 8

a purely schematic partial representation of a further embodiment of the shoe press according to the invention with a press nip formed between a shoe press unit and a tissue cylinder.

Figure 1 shows a purely schematic partial representation of an embodiment a shoe press 10 according to the invention, for example in a Machine for producing a fibrous web, in particular one Tissue or tissue paper web can be used.

The press nip 12 of this shoe press 10 is between a shoe press unit, in the present case a shoe press roll 14 and a drying cylinder 16 formed, through which in addition to the fibrous web a water-absorbing Carrier tape 18 and a waterproof press tape is passed, which in the present case is the press jacket 20 of the shoe press roll 14 acts. The water-absorbing carrier tape 18 can be formed in particular by a felt. In the present The case is the water-absorbing carrier tape 18 between the Press jacket 20 and the fibrous web passed through the press nip 12, the fibrous web touches the drying cylinder 16.

As can be seen from FIG. 1, the shoe press roll 14 has a two-part press shoe 22, a thermal between the two parts Insulating layer 24 is used.

The press shoe 22 can be juxtaposed over several across the web running direction 1 arranged pressure elements 26 against the drying cylinder 16th be pressable.

The drying cylinder 16 can be, for example, a Yankee cylinder act.

The water-absorbing carrier tape formed, for example, by a felt 18 can have different properties in the thickness direction exhibit. For example, the one facing the fibrous web Side of the carrier tape 18 have a finer structure than that of the side facing away from the fibrous web. The press jacket 20 can be a smooth, have a grooved and / or blanked surface. At the Drying cylinder 16 can at least one other, not shown here Press nip be formed. In the direction of web travel 1 in front of the drying cylinder 16 an additional press nip can be provided. Basically you can the carrier tape 18 and the fibrous web in the web running direction 1 before Drying cylinder 16 also guided over at least one suction device his. The shoe press unit 14 can have at least one replaceable one Include press shoe 22.

In FIG. 2, the pressure profile or the pressure profile p (L) is one shown conventional shoe press. The pressure p is over the length L of the press nip 12 or the press shoe 22 is applied.

With such a conventional extended gap, there is initially a very gentle pressure rise up to a relatively low maximum pressing pressure p _max . Following the maximum pressing pressure p _{max of} this pressure curve p (L), there is then a rapid pressure drop.

The shoe press 10 according to the invention can now in particular be designed such that the length L of the press nip 12 (see FIG. 1) viewed in the web running direction l is less than or equal to a value of approximately 60 mm and its pressure profile p (L ) has a maximum pressure p _max that is greater than or equal to a value of about 3.3 MPa.

FIG. 3 shows the pressure pressure curve p (L) of an exemplary embodiment of such a shoe press 10 according to the invention with a relatively short press shoe 22. Starting from the beginning of the gap, this results in an extreme increase in the pressing pressure up to a relatively high maximum pressing pressure p _max . Following this maximum pressing pressure p _max , the pressing pressure in the end region then drops very quickly.

It can also be seen from FIG. 3 that the pressure profile p (L) resulting over the press nip length L is asymmetrical. The maximum press pressure p _max lies in the rear half of the press nip length L when viewed in the direction of web travel l.

FIG. 4 shows a comparison of the pressure pressure curve p ₁₀ (L) of an exemplary embodiment of the shoe press 10 according to the invention with a relatively short press shoe 12 with the pressure pressure curve p _S (L) of a conventional press provided with a suction press roll. Compared to the conventional press, there is in particular a shorter press nip and a higher maximum press pressure p _max . In the present case, the maximum line force generated in the press nip was 90 kN / m in each case.

In an alternative embodiment variant of the shoe press 14 according to the invention, the length L of the press nip 12 (see FIG. 1) viewed in the web running direction l can be greater than a value of approximately 80 mm and the pressure profile p _L resulting from the press nip length _{L means} a maximum press pressure p _max have less than or equal to a value of, for example, about 2 MPa. The maximum line force generated in the press nip can be in particular in a range from approximately 90 to approximately 110 kN / m. At higher maximum line forces, which are normally no longer possible with the usual, not additionally reinforced Yankee cylinders (see, for example, the high value of 270 kN / m indicated in FIG. 5), a higher maximum pressing pressure p _max conceivable.

FIG. 5 shows a comparison of the pressure pressure curve p ₁₀ (L) of an exemplary embodiment of such a shoe press 10 according to the invention with a relatively long press shoe 12 with the pressure pressure curve p _S (L) of a conventional press provided with a suction press roll.

While the pressure pressure curve p ₁₀ (L) of the shoe press according to the invention is shown both for a maximum line force of 90 kN / m and for a higher maximum line force of 270 kN / m, the pressure pressure curve p _S (L) of the conventional press is only for one maximum line force of 90 kN / m is shown.

According to this FIG. 5, the shoe press 10 according to the invention results in a significantly longer press nip 12. In addition, the corresponding press pressure curve p ₁₀ (L) has a significantly lower maximum press pressure p _max (cf. the hatched lower hatched for a maximum line force of 90 kN / m) Press pressure curve p ₁₀ (L)). It can also be seen from FIG. 5 that the maximum pressing pressure p _max, even with a considerably higher maximum line force of 270 kN / m here, is not higher than the maximum pressing pressure p _{max of} the conventional press, for which in the present case a maximum line force of 90 kN / m is specified.

FIG. 6 shows the specific volume versus the dry content, the results V ₁₀ obtained for an exemplary embodiment of the shoe press 10 according to the invention with a relatively short press shoe 22 again being compared with the results V _S for a conventional press provided with a suction press roll. If one assumes a constant maximum line force of 90 kN / m in both cases, an increase in the dry content by 2.5% and an increase in the specific volume by 5% can be achieved compared to the conventional press. With a higher maximum line force of, for example, 270 kN / m, for example, a further increase in the dry matter content by 4.5% can be achieved, in total 2.5% + 4.5% = 7% more than with the conventional suction press roll, in which If only 10% of the specific volume has to be accepted.

FIG. 7 shows the specific volume versus the dry content, the results V ₁₀ obtained for an exemplary embodiment of the shoe press 10 according to the invention with a relatively long press shoe 12 again being compared with the results V _S for a conventional press provided with a suction press roll.

Assuming a constant maximum line pressure of 90 kN / m off, an increase in the specific Volume of 20% can be achieved, which results in a correspondingly higher Quality results. In contrast, with the same specific volume an increase in dryness by 4% can be achieved Energy is saved or a higher production rate is achieved. As with 7 can be seen, is here of a constant maximum Line force of 270 kN / m assumed.

FIG. 8 shows a further embodiment in a schematic partial representation a shoe press 10 according to the invention.

With short shoes 22 it has been shown that the angle α between the at the end of the press nip 12 applied to the drying or tissue cylinder 16 Tangent 30 and the carrier tape running out of the press nip 12 18 has a significant influence on the dry content of the tissue web 28 has. The present embodiment is now characterized by this from that in particular for the manufacture of a tissue web 28 this angle α between the at the end of the press nip 12 to the drying or tissue cylinder 16 created tangent 30 and the tapering from the press nip 12 Carrier tape 18 ≥ 10 °, in particular ≥ 18 ° and preferably ≥ Is 20 °. This results in applications with suction press rolls a dry matter increase of approx. 1 to 3%. The press belt 18 is preferably grooved and / or blind drilled.

Otherwise, the present shoe press 10 has again, for example the same structure as the elements corresponding to each other are provided with the same reference numerals.

Reference list

10th

Shoe press

12th

Press nip

14

Shoe press roll

16

Drying cylinder

18th

Carrier tape

20th

Press belt, press jacket

22

Press shoe

24th

thermal insulation layer

26

Pressing element

28

Tissue web

30th

tangent

L

Press nip length

l

Web direction

p (L)

Press pressure curve, pressure profile

p _max

maximum pressure

α

angle

Claims (17)

Machine for producing a fibrous web, in particular tissue or hygiene paper web, with at least one press nip (12) formed between a shoe press unit (14) and a drying or tissue cylinder (16), through which a water-absorbing carrier tape (18), a water-impermeable press tape ( 20) and the fibrous web is passed through,
characterized by
that at least one press nip (12) is provided between a shoe press unit (14) and the drying or tissue cylinder (16), the length (L) considered in the web running direction (l) of which is less than or equal to a value of approximately 60 mm and whose pressure profile (p (L)) resulting over the press nip length (L) has a maximum press pressure (p _max ) which is greater than or equal to a value of approximately 3.3 MPa. Machine according to claim 1,
characterized by
that the press nip length (L) is greater than or equal to a value of about 50 mm and the maximum press pressure (p _max ) is greater than or equal to a value of about 4.3 MPa, preferably the press nip length (L) in a range of about 37 mm and the maximum pressing pressure (p _max ) is in a range of about 4.8 MPa. Machine according to one of the preceding claims,
characterized by
that in particular for producing a tissue web (28) the angle (α) between the tangent (30) applied to the drying cylinder (16) at the end of the press nip (12) and the carrier tape (18) running out of the press nip (12) ≥ 10 ° , in particular ≥ 18 ° and preferably ≥ 20 °, the press belt (20) preferably being grooved and / or blind-drilled. Machine for producing a fibrous web, in particular tissue or hygiene paper web, with at least one press nip (12) formed between a shoe press unit (14) and a drying or tissue cylinder (16), through which a water-absorbing carrier tape (18), a water-impermeable press tape ( 20) and the fibrous web is passed through,
characterized by
that at least one press nip (12) is provided between a shoe press unit (14) and the drying or tissue cylinder (16), the length (L) considered in the web running direction (l) of which is greater than a value of approximately 80 mm and preferably less than 200 mm, in particular at most 150 mm, and whose pressure profile (p (L)) resulting over the press nip length (L) has a maximum press pressure (p _max ) which is mine or equal to a value of approximately 2 MPa. Machine according to one of the preceding claims,
characterized by
that the maximum line force generated in the press nip (12) is in a range from about 90 to about 110 kN / m, and / or that the shoe press unit (14) comprises a press shoe (22) which extends across several transverse to the web running direction (l) pressure elements (26) which are arranged next to one another and can be actuated independently of one another can be pressed against the drying cylinder. Machine according to one of the preceding claims,
characterized by
that a Yankee cylinder is provided as the drying cylinder (16) and / or that the pressure profile (p (L)) resulting over the press nip length (L) is asymmetrical. Machine according to one of the preceding claims,
characterized by
that the press nip length (L) is less than or equal to a value of approximately 60 mm and the pressure profile (p (L)) has a maximum press pressure (p _max ) which is greater than or equal to a value of approximately 3.3 MPa, and that the maximum press pressure (p _max ) in the rear half of the press nip length (L) when viewed in the direction of web travel (l). Machine according to one of claims 1 to 6, characterized in that
that the press nip length (L) is greater than a value of approximately 80 mm and the pressure profile (p (L)) has a maximum press pressure (p _max ) which is less than or equal to a value of approximately 2 MPa, and that the maximum press pressure (p _max ) lies in the rear quarter of the press nip length (L) when viewed in the web running direction (l). Machine according to one of the preceding claims,
characterized by
that the mean pressure rise gradient in the section of the pressure profile (p (L)) from the beginning of the gap to the maximum pressing pressure (p _max ) is greater than or equal to a value of about 40 kPa / mm, in particular greater than or equal to about 60 kPa / mm, for a new carrier tape. mm and preferably greater than or equal to about 120 kPa / mm, and / or that the mean pressure drop gradient in the end region of the pressure profile (p (L)) for a new carrier tape is greater than or equal to a value of about 300 kPa / mm, in particular greater than or equal about 500 kPa / mm, suitably greater than or equal to about 800 kPa / mm and preferably greater than or equal to about 960 kPa / mm, and / or that the water-absorbing carrier tape (18) in the press nip (12) between the water-impermeable press belt (20) and the fibrous web lies and the fibrous web contacts the drying cylinder (16), and / or that a felt is provided as the water-absorbing carrier tape (18). Machine according to one of the preceding claims,
characterized by
that the water-absorbing carrier tape (18) has a different nature in the thickness direction and that preferably the side of the carrier tape (18) facing the fibrous web has a finer structure than its side facing away from the fibrous web. Machine according to one of the preceding claims,
characterized by
that the press belt (20) has a smooth, grooved and / or surface provided with blind holes, and / or that at least one further press nip (12) is formed on the drying cylinder (16), preferably at least two on the drying cylinder (16) by means of a respective one Shoe press unit (14) press nips (12) are provided. Machine according to one of the preceding claims,
characterized by
that an additional press nip (12) is provided in the web running direction (l) in front of the drying cylinder (16), and / or that the carrier tape (18) and the fibrous web are guided in front of the drying cylinder (16) in the web running direction (l) via at least one suction device , wherein at least one suction device is preferably provided, which comprises a suction roll and / or a suction shoe, and / or that a shoe press roll (14) is provided as the shoe press unit, the press belt preferably being formed by the press jacket (20) of the shoe press roll (14) . Machine according to one of the preceding claims,
characterized by
that the shoe press unit (14) comprises at least one exchangeable press shoe (22), and / or that a structured felt in the manner of an embossed sieve or felt provided with bumps, ie a so-called "imprinting fabric" or "imprinting felt", is used as the carrier tape (18) "or a" patterning fabric "or" patterning felt "with a roughly structured surface is provided. Use of the machine according to one of the preceding claims for the production of a fibrous web using so-called "curled fibers". Method for producing a fibrous web, in particular tissue or hygienic paper web, in which the fibrous web to be dewatered is passed through a press nip (12) together with a carrier tape (18),
characterized by
that the fibrous web to be dewatered in the press nip (12) is subjected to a press pressure of at least 3.3 MPa for a period of at most 3 ms. Process for the production of a fibrous web, in particular tissue or hygienic paper web, in which the fibrous web to be dewatered is guided together with a belt (18) through a press nip (12),
characterized by
that the fibrous web to be dewatered in the press nip (12) is subjected to a press pressure of at most 2 MPa for a period of at least 3.5 ms. Method according to one of the preceding claims,
characterized by
the use of so-called "curled fibers".

Images