Machine for the production of a fibrous material web

Abstract

The invention relates to a machine for producing a fibrous material web, in particular a packaging paper or cardboard web. The machine comprises at least one, preferably two, double-felted shoe presses mounted one behind the other in the direction of movement of the web, and at least one single-felted shoe press mounted downstream of the two double-felted shoe presses in the direction of movement, particularly in the form of a smoothing press.

Description

[0001] The invention relates to a machine for producing a fibrous web, in particular a packaging paper or cardboard web, with at least one, preferably two double-felted shoe presses arranged one behind the other in the web running direction.

[0002] For packaging paper and board with medium to high grammages or basis weights of 80 g / m² to 500 g / m², a quadruple-felted Tandem NipcoFlex press (TNFP) is typically used. This press consists of two shoe presses arranged one behind the other, each with a double felt. At machine or web speeds below 1200 m / min, suction cups are generally used for web separation, while suction felt guide rollers are generally used for machine or web speeds above 1200 m / min.

[0003] The documents DE 10 2010 031 320 A1, EP 1 375 740 A1 and DE 201 17 558 U1 show machines with shoe press devices.

[0004] Fig. 1 shows a 4-fold felted TNFP press 10, whose two shoe presses 12 are each provided with a suction felt guide roller 14 for web separation. In contrast, Fig. 2 a quadruple-felted TNFP press 10, whose shoe presses 12 each have a separating suction device 16 for web separation. This embodiment is not covered by the claims.

[0005] For some packaging types, especially those with a white cover containing virgin fiber or virtually all types of board, a smoothing press is used after the TNFP press to particularly smooth the good side of the paper web. Felt cannot be used for this, as this requires a smooth surface. Depending on the speed requirements, two common options are currently available for the smoothing press: an offset press or a spreader press.

[0006] In an offset press, the fiber web is drawn in a long, open draw from the TNFP press into the nip of the offset press, which is formed between a smooth top roll and a smooth bottom roll. After the nip, the fiber web is guided in a long, open draw to the downstream dryer group for transfer.

[0007] Fig. 3shows a schematic representation of a quadruple-felted TNFP press 10, followed by such an offset press 18. The two double-felted shoe presses 12 of the TNFP press 10 are, in the present case, again equipped with separating suction cups 16 for web separation. This embodiment is not covered by the claims.

[0008] One of the advantages of an offset press is that it is the most cost-effective calendering press, and it smooths the top and bottom sides of the fibrous web with smooth rollers. However, in most cases, smoothing only one side of the web is sufficient. Another particular advantage is that only one pulper 20 is required to collect the resulting waste (see again). Fig. 3 ).

[0009] However, an offset press also has a number of disadvantages. For example, there are two open draws between the TNFP press and the offset press, and one downstream of the offset press. The fiber web must be pulled off smooth rollers twice, with large speed differences that generate the release force. The maximum web travel speed is therefore limited by the strength of the web and the quality of the material with regard to inclusions of foreign bodies that act as predetermined breaking points for tears. Since material quality has been continuously declining in recent years with regard to strength and purity of the material (foreign bodies), this is a relevant problem. Since no transport medium such as felt is used, the fiber web must overcome very long open draws before and after the offset press.The web is exposed to high stretches due to air currents and gravity, which requires high tension to compensate. These high tensions cause local fiber separation within the fiber network of the fibrous web. In particular, the splitting strength and all associated quality parameters drop significantly. The fibrous web also becomes porous. Therefore, the offset press can usually only be used at web speeds of up to 1000 m / min.

[0010] Another disadvantage of offset presses concerns the transfer of the fiber web. This can only be guided web-width to the second bottom felt of the TNFP press. After that, a sliver must be cut, and this sliver must first be fed through the open nip of the offset press to the dryer section. For this purpose, a cable cutter must be used upstream of the nip. In addition, the fiber web must be deflected into the cable cutter, which must be done manually and carries a very high risk of accidents. The fiber web can only be spread wide after the sliver has been transferred and the offset press has been closed. Transferring the strip in two open passes is very time-consuming, as the process takes a long time and must be repeated frequently because the delicate sliver tears easily.

[0011] Since an offset press has neither a felt nor a press roller, the fiber web cannot be dewatered and therefore the dry content cannot be increased.

[0012] Although smoothing is achieved with the offset roller by smooth contact partners, for example ceramic or hard rubber rollers, the residence time of the fiber web in the nip is very limited. A roller nip is used that has a contact length of only a few centimeters (between 20 and 50 mm). Especially with heavier packaging and board types that emerge from the preceding press with very high roughness, such a short contact length is not sufficient for smoothing. To compensate for this, a high line load is often applied for the hard nip without soft rollers and without compressible clothing in order to compensate for the lack of residence time during smoothing with high peak pressure. However, this is counterproductive, especially with board types, since the specific volume is of great importance here. Board production is only economical if a board consumes as few fibers as possible during production for a required thickness.

[0013] In a laying press or straight-through press, the fiber web is laid onto a felt after an open draw from the TNFP press. Fig. 4shows a schematic representation of a quadruple-felted TNFP press 10, followed by such a spreading press 22. In this case, the two shoe presses 12 of the TNFP press 10 are again provided with separating suction cups 16 for web separation. This embodiment is not covered by the claims. In this case, the fibrous web is laid onto a felt 24 of the spreading press 22 after an open draw from the second shoe press 12 of the TNFP press 10. To prevent a disruptive air layer from forming between the fibrous web and the felt, which could lead to web travel problems, a suction felt guide roll 26 is usually used. The felt 24 transports the fibrous web into the nip 28 of the spreading press 22, which is formed between a smooth top roll 30 and a press roll 32 on the felt side. After the nip 28, the fibrous web follows the smooth top roll 30.For the transfer of the fibrous web to the downstream dryer group 34 of the dryer section, the fibrous web must be drawn off in an open draw. One of the advantages of a spreading press is that the fibrous web is supported by a felt and therefore does not have to overcome long open draws. This allows the comprehensive concept of such a spreading press to be used for web speeds > 1000 m / min. A further advantage is that, unlike an offset press, such a spreading press uses a press roll on the felt side. Such a press roll is equipped with a storage volume and can also contribute to dewatering.

[0014] However, due to the design of the laying press with roller nips and line loads of 40 to 140 kN / m, there is usually little or no dewatering, resulting in little or no increase in dry content. Due to the required felt conditioning, remoistening and a decrease in dry content can often occur after the laying press.

[0015] One of the disadvantages of a spreading press is that there are two open draws between the TNFP press and the one after the spreading press. However, these open draws are significantly shorter in a spreading press than in an offset press. Another disadvantage of the spreading press concerns the transfer of the fibrous web. The fibrous web can only be guided web-width-wide to the second bottom felt of the TNFP press. After that, a strip must be cut, which must first be guided to the top roller of the spreading press and then, in a second step, be transferred from the top roller of the spreading press to the dryer section. The disadvantages of this type of two-step transfer have already been mentioned above.

[0016] Although a spreading press has a felt guide with associated felt conditioning, it can only contribute insignificantly to dewatering. Thus, a relatively high level of effort is required, while the benefit is limited to smoothing only one side. Since a spreading press has a felt in the basement, two Pulper 20s are required (see Fig. Fig. 4 ) to accommodate the waste generated after the second and third presses. Due to the felt in the basement, both positions cannot be combined into one pulper, which entails significant additional costs.

[0017] The invention is based on the object of providing a machine of the type mentioned above, particularly suitable for the production of medium to heavy packaging papers and cardboard types at machine or web speeds > 1000 m / min, in which the aforementioned problems are eliminated. In particular, a very high smoothing effect is to be achieved. At the same time, the specific volume of the fibrous web in cardboard types is to be preserved, or, with a correspondingly different shoe design or pressure profile in the shoe press, an increase in compaction or associated properties such as SCT or TSI in the transverse direction can be achieved with simultaneous smoothing.During the transfer of the fibrous web from the upstream press section and into the downstream dryer section, only minimal draws should occur to protect the fibrous web as much as possible and ensure ply strength and all associated quality properties, such as SCT in the cross direction. Web transfer should be significantly simpler and safer, and above all, faster, to minimize potential production downtime. Ultimately, a single pulper should suffice.

[0018] According to the invention, this object is achieved by a machine having the features of claim 1. An advantageous use of the machine according to the invention is specified in claim 37. Preferred embodiments of the machine according to the invention emerge from the subclaims, the description, and the drawing.

[0019] The machine according to the invention for producing a fibrous web, in particular a packaging paper or cardboard web, comprises at least one, preferably two, double-felted shoe presses arranged one behind the other in the web running direction and at least one single-felted shoe press arranged behind the two double-felted shoe presses in the web running direction, in particular designed as a smooth press.

[0020] This design achieves a very high smoothing effect, particularly for medium to heavy packaging papers and board types at machine or web speeds > 1000 m / min. At the same time, the specific volume of the fiber web is protected for board types. With a correspondingly different shoe design or pressure profile in the shoe press, an increase in compaction is also possible, which also ensures associated properties such as SCT and TSI in the cross direction. During the transfer of the fiber web from the preceding press section to the subsequent dryer section, only minimal tension occurs, thus protecting the fiber web accordingly. This ensures the layer strength and all other associated quality properties such as SCT in the cross direction.The transfer of the fibrous web is significantly simplified and safer, and can be completed more quickly, thus minimizing production downtimes. Furthermore, only a single pulper is required, thus saving costs. For ever-increasing production rates, gentle dewatering is achieved without leaching of the fibrous web due to overly intensive dewatering. According to the invention, the total dewatering is distributed across a larger number of dewatering nips, including the single-felted shoe press nip of the single-felted shoe press serving as the smoothing roll. The shoe press nips result in relatively gentle dewatering.

[0021] The machine according to the invention can be used in particular for the production of medium to heavy packaging paper and / or cardboard with a grammage or basis weight of 80 g / m 2< to 500 g / m 2< at web speeds > 1000 m / min.

[0022] Preferably, a line force of ≥ 400 kN / m, in particular ≥ 500 kN / m, and preferably ≥ 700 kN / m can be generated in a respective shoe press nip of the shoe presses. To ensure sufficient dewatering time, a respective press shoe of the shoe presses advantageously has a length of ≥ 250 mm.

[0023] It is particularly advantageous if at least one simply felted shoe press designed as a smoothing press comprises a particularly upper shoe press roll and a particularly lower smooth counter roll, in particular one provided with a ceramic or hard rubber surface. The shoe press roll and the counter roll can be arranged vertically one above the other, for example. In this case, the respective shoe press nip is positioned essentially straight or parallel to the horizontal, whereby the unsupported fibrous web can be fed upwards almost vertically without falling off.

[0024] According to a further advantageous embodiment, at least one simply felted shoe press designed as a smoothing press comprises a particularly upper shoe press roll and a particularly lower counter roll, around which a transfer belt is wrapped. The fibrous web can be transported into the dryer section in a closed web path via such a transfer belt. The shoe press roll and the counter roll, around which a transfer belt is wrapped, can, for example, be arranged at least substantially vertically one above the other, resulting in a shoe press nip that is straight or at least substantially parallel to the horizontal. In this case, the fibrous web can be fed upwards at least substantially vertically without falling off. However, an embodiment is also conceivable in which the shoe press roll and the counter roll, around which a transfer belt is wrapped, are offset from the vertical orare arranged at an angle, so that an inclined arrangement of the simply felted shoe press results, into which the fiber web can run supported by the transfer belt and with which a particularly high collection capacity of the tub after the shoe press nip is enabled.

[0025] As mentioned, the fibrous web can be transferred into the dryer section in a closed web path via the transfer belt that wraps around the counter roll of a simply felted shoe press.

[0026] It is particularly advantageous if each transfer belt loop is guided without an external guide roller.

[0027] The peak pressure in the shoe press nip of the last single-felted shoe press is preferably equal to or greater than the peak pressure in the shoe press nips of the preceding shoe presses. To transport the fiber web as wrinkle-free as possible through all shoe press nips and into the subsequent dryer group of the dryer section, a web speed difference of 0.2% to 3.5% is advantageously provided between successive shoe presses.

[0028] A common pulper can be assigned to the various positions on the machine where broke is generated, thus saving costs. When the fiber web breaks in the drying section, the resulting broke can be guided into the common pulper via the first drying cylinder (viewed in the web travel direction). A repeated transfer of the fiber web through the press section is not necessary. Preferably, at least one, preferably two, doctor blades are assigned to the first drying cylinder of the drying section (viewed in the web travel direction) for removing the fiber web and cleaning the drying cylinder.

[0029] In order to avoid self-transfer and to discharge the fibrous web in a stable manner, the horizontal distance between the centers of the first drying cylinder or roll, viewed in the web travel direction, and the following first stabilizing roll of the drying section is preferably ≥ 80%, in particular ≥ 90% and preferably ≥ 95% of the sum of half the diameters of the two rolls.

[0030] To achieve the highest possible cleaning effect, a high-performance cleaning unit with at least one, preferably at least two rows of nozzles for generating at least two individual jets each, which impinge obliquely on the transfer belt surface from different directions, is advantageously arranged on the transfer belt wrapping around the counter roll of a respective single-felted shoe press. Very fine rows of nozzles can be used in particular. The pressure of the nozzles of the high-performance cleaning unit is preferably ≥ 50 bar, in particular ≥ 100 bar, and preferably ≥ 120 bar. The diameter of the nozzles of the high-performance cleaning unit is advantageously ≤ 0.7 mm, in particular ≤ 0.5 mm, and preferably ≤ 0.3 mm.

[0031] The transfer belt wrapping around the counter roll of a single-felted shoe press is advantageously provided with a scraper downstream of the high-performance cleaning unit to remove web residues from the transfer and excess water. The high-performance cleaning unit and the scraper are preferably arranged opposite an outlet roll provided downstream of the shoe press nip of the single-felted shoe press to achieve a corresponding supporting effect.

[0032] The separation of the clothing or felts of a respective double-felted shoe press in the web travel direction after each shoe press nip is achieved by means of a suction felt guide roller, which is arranged in particular in the loop of the bottom felt. This suction felt guide roller or a felt guide roller following it in the felt travel direction and arranged in front of a tube suction device is provided with a drive. It is also particularly advantageous if the suction felt guide roller is wrapped around the respective felt, in particular the bottom felt, at an angle of ≥ 15°, in particular ≥ 30°, and preferably ≥ 40°.

[0033] The transfer distance of the fibrous web between adjacent suction felt guide rollers of the first and second shoe presses viewed in the web running direction and between adjacent suction felt guide rollers of the second and third shoe presses viewed in the web running direction is preferably < 900 mm, in particular < 750 mm and preferably < 600 mm.

[0034] It is also particularly advantageous if the subsequent wrapping of the counter roll of a respective shoe press by the respective felt or transfer belt after the shoe press nip is ≥ 20 mm, in particular ≥ 45 mm and preferably ≥ 70 mm.

[0035] Advantageously, one of the guide rollers, around which the transfer belt is guided, which wraps around the counter roller of a respective single-felted shoe press, is provided with a drive.

[0036] The first drying group of the drying section, viewed in the web running direction, is advantageously single-row and designed with ≤ 4, in particular ≤ 3 and preferably ≤ 2 drying cylinders.

[0037] The transfer belt and felt wrapping around the counter roll of a single-felted shoe press can, in particular, enter the single-felted shoe press nip in a closed state. This prevents the fiber web from falling off, even at a basis weight of > 140 g / m².

[0038] It is also advantageous if the transfer belt that wraps around the counter roll of a single-felted shoe press comprises a base fabric similar to a dryer screen, which is permeated with polyurethane. Such a transfer belt is more cost-effective than felt-based belts.

[0039] The transfer belt wrapping around the counter roll of a respective single-felted shoe press preferably has a surface roughness, in particular in the web running direction, of Rz ≤ 12 µm, in particular ≤ 10 µm and preferably ≤ 8 µm.

[0040] The transfer distance on the transfer belt wrapping around the counter roll of a respective simply felted shoe press after its simply felted shoe press nip is advantageously ≤ 2.5 m, in particular ≤ 2.0 m and preferably ≤ 1.5 m.

[0041] In certain cases it is also advantageous if the separation of the clothing or felts of a respective double-felted shoe press in the web running direction after the respective shoe press nip takes place by means of a separating suction device. Such a separating suction device is provided in particular with five and preferably with three suction slots. The embodiments with separating suction devices described below are not covered by the claims. It is also particularly advantageous if, when the clothing or felts of a respective double-felted shoe press are separated in the web running direction after the respective shoe press nip by means of a separating suction device, the transfer distance after the separating suction device until the fibrous web is removed into the next driven group is ≤ 1600 mm.

[0042] In particular, when the clothing or felts of a respective double-felted shoe press are separated in the web running direction after the respective shoe press nip by means of a separating suction device, the first guide roller provided after the transfer section in the lower felt loop of a respective double-felted shoe press is preferably provided with a drive.

[0043] However, as an alternative to this, an embodiment is also conceivable in which, particularly when the clothing or felts of a respective double-felted shoe press are separated in the web running direction after the respective shoe press nip by means of a separating suction device, a guide roller provided after the first guide roller following the transfer section in the lower felt loop of a respective double-felted shoe press and arranged in the felt running direction upstream of a tube suction device is provided with a drive.

[0044] Preferably, a respective suction felt guide roll provided for separating the clothing or felts of a double-felted shoe press in the web travel direction after a respective shoe press nip has at least two suction zones, at least one of which is designed as a high-vacuum zone. The respective suction felt guide roll preferably has three zones, two of which are designed as high-vacuum zones.

[0045] It is particularly advantageous if each high-vacuum zone has a vacuum of ≥ 35 kPa, in particular ≥ 45 kPa, and preferably ≥ 50 kPa. One of the guide rollers provided after the single-felted shoe press nip of a single-felted shoe press in its transfer belt loop is expediently provided with a drive.

[0046] According to a further practical embodiment of the machine according to the invention, two discharge rollers are provided in the transfer belt loop of a respective single-felted shoe press immediately after its single-felted shoe press nip. On these discharge rollers, viewed in the direction of transfer belt travel, a high-performance unit and then at least one transfer belt scraper are arranged. The high-performance unit and the at least one scraper are preferably each arranged opposite a roller, thus achieving optimal support and providing sufficient space for the components.

[0047] The machine according to the invention can be used in particular for the production of medium to heavy packaging paper and / or cardboard with a basis weight of 80 g / m 2< to 500 g / m 2< at web speeds > 1000 m / min.

[0048] Embodiments of the machine according to the invention are described below with reference to the drawing, in which: Fig. 1 a schematic representation of a 4-fold felted TNFP press with suction felt guide rolls, Fig. 2 a schematic representation of a 4-fold felted TNFP press with separating suction cups, Fig. 3 a schematic representation of a 4-fold felted TNFP press with a downstream offset press, Fig. 4 a schematic representation of a 4-fold felted TNFP press with a laying press, Fig. 5 a schematic representation of an exemplary embodiment of a machine according to the invention with two double-felted shoe presses arranged one behind the other in the web running direction and a single-felted shoe press arranged behind them in the web running direction as a smoothing press with a smooth lower roll, Fig.6 a schematic representation of an exemplary embodiment of a machine according to the invention with two shoe presses arranged one behind the other in the web running direction, each with a double felt, and a single felted shoe press arranged behind them in the web running direction as a smoothing press with a shoe press roll and a counter roll wrapped by a transfer belt, which are arranged vertically one above the other, and Fig. 7 a schematic representation of a machine according to the embodiment according to . Fig. 6 comparable exemplary embodiment of a machine according to the invention, wherein the shoe press roll and the counter roll wrapped by the transfer belt of the simply felted shoe press intended as a smoothing press are, however, offset from the vertical or arranged diagonally one above the other.

[0049] The Fig. 5 to 7show, in schematic representations, three exemplary embodiments of a machine 40 according to the invention for producing a fibrous web, in particular a packaging paper or cardboard web. The machine 40 comprises two double-felted shoe presses 42 arranged one behind the other in the web travel direction L, and a single-felted shoe press 44 arranged as a smoothing press behind the two double-felted shoe presses 42 in the web travel direction L. Each shoe press 42, 44 comprises an upper shoe press roll 46 and a lower counter roll 48. The shoe press roll 46 and counter roll 48 of at least the two double-felted shoe presses 42 are each offset from the vertical and thus arranged diagonally one above the other.

[0050] The separation of the clothing or felts of a respective double-felted shoe press 42 in the web running direction L after a respective shoe press nip is carried out by means of a suction felt guide roller 52 arranged in particular in the loop of the bottom felt.

[0051] In the Fig. 5In the embodiment shown, the lower counter roll 48 of the singly felted shoe press 44 intended as a smoothing press is provided as a smooth roll. Unlike the shoe press roll 46 and counter roll 48 of the two preceding shoe presses 42, the shoe press roll 46 and the smooth counter roll 48 of the singly felted shoe press 44 intended as a smoothing press are arranged vertically one above the other. The fibrous web, together with a felt 54, is guided through the shoe press nip of the single-sided felted shoe press 44 intended as a smoothing press. Following the shoe press nip, the fibrous web is carried along by the smooth counter roll 48 of the singly felted press 44 and removed from the smooth counter roll 48 by a dryer wire 56 of a dryer group 58 of the subsequent dryer section.

[0052] A common pulper 60 is assigned to the various positions of the machine 40 where rejects are generated.

[0053] The Fig. 6 The embodiment of a machine 40 according to the invention shown in FIG. 1 differs from that according to Fig. 5 Firstly, in that the single-felted shoe press 44, which is provided as a smoothing press, has a counter roll 48 wrapped by a transfer belt 62 and the fibrous web is removed from the transfer belt 62 following the shoe press nip of the single-sided felted shoe press 44, which is provided as a smoothing press, by the drying wire 56 of the drying group 58 of the following drying section. In this embodiment, according to Fig. 6 the shoe press roll 46 and the counter roll of the single-felted shoe press 44 intended as a smoothing press are arranged vertically one above the other, so that an at least substantially horizontal press nip results.

[0054] Even in the embodiment according to Fig. 7The counter roller 48 of the shoe press 44, which is provided as a smoothing press and is provided opposite the shoe press roller 46, is again wrapped by a transfer belt 62. Unlike the embodiment according to Fig. 6 In the present case, however, the shoe press roller 46 and the counter roller 48 wrapped by the transfer belt 62 are offset from the vertical or arranged obliquely one above the other, so that a shoe press nip is produced which is inclined relative to the horizontal.

[0055] For all in the Fig. 5 to 7 In the exemplary embodiments of a machine 40 according to the invention shown, a common pulper 60 is assigned to the various positions of the machine 40 at which rejects are generated.

[0056] While in the embodiment according to Fig. 5a press section in the style of a Tripple NipcoFlex press with a smooth roller at the bottom of the third shoe press results in the two embodiments according to the Fig. 6 and 7 a machine 40 according to the invention, each with a press section in the manner of a triple NipcoFlex press with closed draw and transfer belt in the third shoe press below.

[0057] At the various Fig. 5 to 7 In the exemplary embodiments of the machine 40 according to the invention shown, when the fibrous web breaks in the drying section, the resulting broke can be guided into the common pulper 60 via the first drying cylinder 64, viewed in the web travel direction L. Two scrapers 66 are assigned to the first drying cylinder 64 of the drying section for removing the fibrous web and for cleaning the drying cylinder 64. List of reference symbols

[0058] 10TNFP press 12Shoe press 14Suction felt guide roll 16Separation vacuum 18Offset press 20Pulper 22Laying press 24Felt 26Suction felt guide roll 28Nip 30Smooth top roll 32Press roll 34Dryer group 40 Machine 42 Double-felted shoe press 44 Single-felted shoe press 46 Shoe press roll 48 Counter roll 50 Felt 52 Suction felt roll 52 Felt 56 Dryer screen 58 Dryer group 60 Pulper 62 Transfer belt 64 First drying cylinder 66 Doctor LWeb direction

Claims

1. Machine (40) for producing a fibrous web, in particular a packaging paper or cardboard web, having at least one, preferably two double-felted shoe presses (42) disposed one behind the other in the web running direction (L) and at least one single-felted shoe press (44), in particular embodied as a smoothing press, downstream of the, or the two, double-felted shoe press(es) (42) in the web running direction (L), characterized in that the separation of the clothings or felts (50) of a respective double-felted shoe press (42) downstream of a respective shoe press nip in the web running direction (L) takes place by means of a suction felt guide roller (52) disposed in particular in the loop of the bottom felt, wherein the suction felt guide roller (52), or a felt guide roller disposed subsequently in the felt running direction ahead of a tubular suction unit, is provided with a drive.

2. Machine according to Claim 1, characterized in that the suction felt guide roller (52) is wrapped by the respective felt, in particular bottom felt, over an angle of ≥ 15°, in particular ≥ 30° and preferably ≥ 40°.

3. Machine according to one of the preceding claims, characterized in that the transfer section of the fibrous web between mutually adjacent suction felt guide rollers (52) of the first and the second shoe press (42) as viewed in the web running direction (L), and between mutually adjacent suction felt guide rollers of the second and the third shoe press as viewed in the web running direction (L), is in each case < 900 mm, in particular < 750 mm and preferably < 600 mm.

4. Machine according to one of the preceding claims, characterized in that a respective suction felt guide roller (52) provided downstream of a respective shoe press nip for separating the clothings or felts (50) of a double-felted shoe press (42) in the web running direction (L) has at least two suction zones, of which at least one is embodied as a high-vacuum zone, the former preferably having three suction zones, of which two are embodied as high-vacuum zones.

5. Machine according to Claim 4, characterized in that a respective high-vacuum zone has a vacuum of ≥ 35 kPa, in particular ≥ 45 kPa and preferably ≥ 50 kPa.

6. Machine according to one of the preceding claims, characterized in that at least one single-felted shoe press (44) embodied as a smoothing press comprises an in particular upper shoe press roller (46) and an in particular lower smooth counter roller (48) provided in particular with a ceramic or hard rubber surface, wherein the shoe press roller (46) and the counter roller (48) are preferably disposed at least substantially vertically on top of one another.

7. Machine according to one of the preceding claims, characterized in that at least one single-felted shoe press (44) embodied as a smoothing press comprises an in particular upper shoe press roller (46) and an in particular lower counter roller (48), the latter being wrapped by a transfer belt (62), wherein the transfer belt (62) has in particular a surface roughness, especially in the web running direction, of Rz ≤12 µm, in particular ≤ 10 µm and preferably ≤ 8 µm.

8. Machine according to one of the preceding claims, characterized in that the fibrous web is able to be transferred into the drying section in a closed web run via the transfer belt (62) which wraps around the counter roller (48) of a single-felted shoe press (44).

9. Machine according to one of Claims 7 and 8, characterized in that a high-performance cleaning unit having at least one, preferably at least two nozzle rows for generating in each case at least two individual jets is disposed on the transfer belt (62), said jet rows impacting the transfer belt surface obliquely from different directions.

10. Machine according to Claim 9, characterized in that the pressure of the nozzles of the high-performance cleaning unit is ≥ 50 bar, in particular ≥ 100 bar and preferably ≥ 120 bar, and / or the diameter of the nozzles of the high-performance cleaning unit is in each case ≤ 0.7 mm, in particular ≤ 0.5 mm and preferably ≤ 0.3 mm.

11. Machine according to one of the preceding claims, characterized in that one of the guide rollers, around which the transfer belt (62) which wraps around the counter roller (48) of a respective single-felted shoe press (44) is guided, is provided with a drive.

12. Machine according to one of the preceding claims, characterized in that the trailing wrapping of the counter roller (48) of a respective shoe press (42, 44) by the relevant felt (50) or transfer belt (62) after the shoe press nip is ≥ 20 mm, in particular ≥ 45 mm and preferably ≥ 70 mm.

13. Method for producing a fibrous web by means of a machine according to one of the preceding claims, characterized in that the peak pressure in the shoe press nip of the last, single-felted shoe press (44) is equal to or greater than the peak pressure in the shoe press nips of the preceding shoe presses (42).

14. Method according to Claim 13, characterized in that a respective web running speed difference of 0,2% to 3,5% is applied between successive shoe presses (42, 44) in order to guide the fibrous web through the shoe press nips and into the drying section without creases.

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