EP1975314B1 - Machine for producing a tissue paper web - Google Patents

Description

The invention relates to a machine for producing a tissue web, in particular tissue machine in detail with the features of the preamble of claim 1.

Machines for the production of tissue webs are already known in different versions from the prior art. These comprise in the wet part of a former, which is designed depending on the former concept as a twin-wire former or so-called crescent former. In the former case, sheet formation takes place between two dewatering sieves forming a double-wire zone, while in the second case sheet formation takes place in a double-belt zone formed between a felt belt and a dewatering wire. Both formers are preferably designed in roll construction, ie comprise a forming roller whose circumference is partially wrapped by the two endless belts. The separation of the two bands with continuation of the fibrous web with one of the bands takes place either still in the wrapping area with the forming or downstream of this, by both bands are continued together after expiration of the forming roller. In the double belt area the formation takes place in both cases, ie fiber orientation and drainage. The fiber suspension is introduced via a headbox in a wedge-shaped inlet gap formed between the bands. If a separation of the two bands in the area of the forming roll, the fibrous web is taken along the flow line on Formier cylinder of the band, which wraps around the forming roller on its outer circumference with its inner side directly. Such an embodiment is for example in EP 1 120 492 A2 described. The fibrous web is guided according to a first embodiment to the transfer to other machine areas on the wire. Instead of the inner band in the wrapping area, according to a second embodiment, a felt belt can also be used, so that the pulp suspension between a wire belt and a felt belt in the Formierbereich is introduced and separated from the screen belt with the felt belt of the next process stage is supplied.

The document US 2004/0173333 A1 discloses a process for making tissue webs on a modified crescent former tissue machine. After forming the web, it is dewatered in a wet press, which is designed as an air press, to a dry content of 30% to 40% and then dried by a heated drying cylinder.

The patent US 5,578,170 describes a process for the production of tissue webs having improved formation and better strength properties without substantially impairing retention and ply cleanliness. In this process, the web is dewatered by the forming roll only to about 90-99%. The remaining water is sufficient to have enough free fibers for a subsequent step. Downstream of the forming roll, the water remaining in the suspension is dewatered using vibrations.

The document WO 03/074782 A1 relates to an apparatus for forming a web in a paper machine. The device consists of two screens, which are each guided over several Siebleitwalzein. The sieves form an inlet gap for receiving the pulp suspension from a headbox. Furthermore, a first Einwerässerungselement is provided. This consists of a Formierkasten with inside and directed against the screens, rotatably mounted rollers. Through the spaces between the rollers, negative pressure can be applied to the pulp suspension.

The document EP 1233105 A2 shows a twin-wire former with two circumferential sieves for producing a fibrous web from a fiber-material suspension. The former has an unswept forming roll having an open volume having a diameter of less than 1400 mm. The screens wrap around the forming roll at a forming wrap angle of less than 7 °.

Another possibility is as in WO 03/06 2528 A1 described the formation formed on the forming roll after the forming roll to continue to pass between the two belts, two wire belts or a wire belt and a felt belt over a predefined distance and to separate the two belts by means of a separating element. The separating element is designed in the form of a separating suction device. In both embodiments according to the prior art, the fibrous webs at the end of the former at handover to the next processing area a low dry content and depending on the leadership of the bands and thus the double band zone sometimes a very irregular formation.

The invention is therefore based on the object, a shaper of a machine for producing a tissue web further such that the disadvantages of the prior art are avoided, in particular a good formation and a high solids content of the fibrous web is reached at the end of the forming line.

The solution according to the invention is characterized by the features of claim 1. Advantageous embodiments are described in the subclaims.

The machine according to the invention for producing a tissue web, in particular a tissue machine, comprises a former with two endless belts - a first endless belt and a second endless belt - forming a double belt zone, the former being designed as a roll former comprising a forming roller, which is partially wrapped by two bands to form an inlet gap for a disposable from a headbox pulp suspension. The former further comprises a separating suction device for separating the two belts while entraining the fibrous web formed between the belts on a belt. The Trennsaugeinrichtung, which is effective on the inside of the first continuous, the fibrous web circulating belt, with which the inside of the band is guided directly on the outer circumference of the forming roller, is as a flat separating sucker or as a vacuum cleaner with a curved surface executed. In the double belt zone, a dewatering device, comprising at least one dewatering strip, which is effective on one of the two belts, is arranged, and the dewatering device is connected directly upstream of the separating suction device. The drainage device comprises a first Entwässerungsleistenanordnung associated with the first band with at least a first Entwässerungsleiste and the second band associated second Entwässerungsleistenanordnung with at least a second Entwässerungsleiste, wherein the first and second Entwässerungsleisten viewed in the strip running direction in the axial direction are offset from each other. One of the two endless umlautenden bands is designed as a drainage filter belt. The machine according to the invention is characterized in that the other endless circulating belt is designed as a felt belt, wherein Trennsaugeinrichtung is associated with the felt belt and is effective on the inside of the felt belt.

The solution according to the invention makes it possible to build up a dewatering pressure in the fiber suspension or the already formed fiber suspension in the double belt area depending on the design of the dewatering strips, wherein the size and the course of the dewatering pressure in the belt running direction can be determined as a function of the arrangement and design of the dewatering device , Depending on the condition or the condition of the pulp suspension in the region of this dewatering device, the formation may already be completed, i. There is already a consistency in which the fibers are firmly connected to each other, in which case the dewatering device only has the function of additional dewatering or increasing the degree of dewatering in the area of the former. In the other case, in which the formation is not completed, i. is still no fibrous web but still pulp suspension with only partial connection of the fibers present, the pulp suspension is formed and dehydrated by the additional dewatering pressure. In both cases, however, the dry content in the fibrous web in the end of the former or when transferring to other process devices, such as creping cylinder or a press unit, in particular shoe press unit is much higher than in the embodiments of the prior art.

As Entwässerungsleisten can be found on the bandwidth, ie extending transversely to the machine direction strip-shaped elements that are effective with a pressure surface on one of the bands use. The drainage strips or at least the region forming the pressure surface are preferably made of ceramic for reasons of wear. The structure preferably corresponds to that of conventional forming strips or foils, wherein for the formation of the dewatering device parts of known strip devices of other formers for sheet formation in fibrous webs can be used.

The dewatering device is effective on both belts to achieve the most uniform possible filler distribution and homogeneity in the thickness direction of the tissue web, a dewatering pressure is built up on both belts, which propagates through this on the fibrous web and leads to a uniform drainage at the top and bottom.

Depending on the design of the double belt zone and belt guide, the arrangement of the dewatering device of a separating suction device in the double belt zone does not require any additional installation space compared to conventional solutions, so that increased dry contents in the fiber web at the end of the former can be achieved while the machine length remains the same or only slightly larger.

To reduce the storage costs for the individual strips preferably more drainage strips a Entwässerungsleistenanordnung are mounted on a common support means, wherein the strips are either mechanically coupled to each other depending on the type of storage on the support means or free of such a coupling.

In order to ensure a fixed positional relationship between a Entwässerungsleistenanordnung in the band, in which the Trennsaugeinrichtung is effective, and the Trennsaugeinrichtung, the Entwässerungsleistenanordnung is mounted on the housing of the separating sucker. As a result, can be dispensed with separate storage facilities.

Regarding the storage of the individual drainage strips exist depending on the desired drainage process several options. These may be rigidly mounted, resiliently mounted or elastically or, according to a particularly advantageous embodiment, be variably adjustable with respect to their contact force acting on the respective band. In the latter case, the contact pressure on the individual dewatering strip is preferably hydraulically or pneumatically adjustable, with regard to the means for providing the contact pressure, in particular the pressure source to other process systems of the tissue machine can be used and thus no separate pressure source is required by the functional concentration thereby made. The individual strips are then further associated with means for adjusting the size of the contact pressure, so that even with thickness variations always the same contact pressure can be guaranteed.

The arrangement and design of the Entwässerungsleisteneinrichtung is preferably carried out against a flat belt surface described by the tape guide, ie the tape guide in the dewatering device is free from a curvature. It is also conceivable, however, an adaptation of the area spanned by a plurality of spaced in the strip direction drainage strips surface to the tape guide. In this case, the Entwässerungsleistenanordnung may have considered a curved active surface in the tape running direction. The effect of the drainage strips thereby superimposed on the drainage effect due to the additional due to the curvature tensile and compressive stresses on the individual bands.

According to a further development, to increase the degree of dewatering, the individual dewatering strip arrangement can be combined with suction devices.

The dewatering belt used can be formed with uniform or to achieve different drainage rates and thus the leaf surface areas zonal different Siebdurchlässigkeit.

The Trennsaugeinrichtung comprises at least one suction zone, preferably at least two series-connected and individually controllable suction zones for adjusting the pressure conditions in the separation region of the bands are provided. The effective surface of the Trennsaugeinrichtung can be made flat or curved, in the latter case, the Trennsaugeinrichtung can be included in the change in direction of the tape guide.

The leadership of the individual bands also takes place via guide rollers. The former of the machine for producing a tissue web, in particular a tissue former, is constructed in roll construction, i. this comprises a forming roller, which is wrapped in the circumferential direction of the two bands over part of their handling, wherein the double band area is present even after the expiration of the bands from the forming roller and the separation of the bands spaced from this occurs. The two bands form a wedge-shaped gap on the forming roller, in which the pulp suspension via a headbox, which may be constructed one or more layers, is introduced.

The inventively designed former is independent of the further construction of the machine for producing a tissue web.

Figur 1a

verdeutlicht eine erste Ausführung eines ausgeführten Formers mit zwei endlosen umlaufenden Bändern in Form von Entwässerungssiebbändern und Anordnung einer Entwässerungsleistenanordnung im ersten Band;

Figur 1b

verdeutlicht eine weitere Ausführung eines ausgeführten Formers mit zwei endlosen umlaufenden Bändern in Form von Entwässerungssiebbändern und Anordnung einer Entwässerungsleistenanordnung im zweiten Band;

Figur 2a

verdeutlicht eine Ausführung eines erfindungsgemäß ausgeführten Formers mit einem ersten endlosen umlaufenden Siebband und einem Filzband und Anordnung von Entwässerungsleistenanordnungen in beiden Bändern;

Figur 2b

verdeutlicht anhand eines Ausschnittes aus Figur 2a eine alternative Ausführung eines Trennsaugers;

Fig. 3a und 3b

verdeutlichen beispielhaft mögliche Ausgestaltungen der Entwässerungseinrichtung;

Figur 4

verdeutlicht anhand einer konstruktiven Ausführung eine besonders vorteilhafte Ausgestaltung einer Entwässerungsanordnung im Formierbereich.

The solution according to the invention is explained below with reference to figures. The following is shown in detail:

FIG. 1a

illustrates a first embodiment of an executed former with two endless circulating belts in the form of Entwässungssiebbändern and arrangement of a Entwässerungsleistenanordnung in the first band;

FIG. 1b

illustrates another embodiment of an executed former with two endless circulating belts in the form of Entwässungssiebbändern and arrangement of a Entwässerungsleistenanordnung in the second band;

FIG. 2a

illustrates an embodiment of an inventively executed former with a first endless rotating screen belt and a felt belt and arrangement of Entwässerungsleistenanordnungen in both bands;

FIG. 2b

illustrated by a section from FIG. 2a an alternative embodiment of a separating sucker;

Fig. 3a and 3b

exemplify possible embodiments of the drainage device;

FIG. 4

illustrated by a structural design, a particularly advantageous embodiment of a dewatering arrangement in the forming area.

The shaper after the FIGS. 1a and 1b are not exemplary embodiments of the claimed invention.

The FIG. 1a illustrates in a schematic simplified representation of a section of a machine 1 for producing a tissue web the basic structure of an executed former 2, which is part of a Nässeils, for formation and drainage according to a first embodiment. For this purpose, the former 2 comprises a double belt zone 3, which describes a forming region and a dewatering section, in which the pulp suspension S is guided between two endless circulating belts, a first endless circulating belt 5 and a second endless circulating belt 6, forming the forming and drainage region , The former 2 is designed as a roll former. The two endless belts 5 and 6 run in a first dewatering section via a dewatering element 7, which is preferably designed in the form of a forming roller 8. The two continuous endless belts 5 and 6 together form a wedge-shaped inlet gap 9, which receives the pulp suspension S directly from a headbox 10. The separation of the two endless belts 5 and 6 with continuation of the fibrous web F formed from the pulp suspension on one of the two continuous endless belts, here the first circulating endless belt 5, takes place the forming roller 8 and thus the first dewatering section I downstream. For this purpose, the fibrous web F continuing circulating belt, here the first endless circulating belt 5, a decrease or separation device 11 assigned, which is designed as Trennsaugeinrichtung 12. This becomes effective on the inside 13 of the first endless belt 5, with which the band 5 is guided directly on the outer circumference 4 of the forming roller 8. The area between the outlet A of the first endless belt 5 from the forming roller 8 or the two belts 5, 6 from the outer periphery 4 of the forming roller 8 and the separation of the two endless belts 5 in the region of the separating suction device 12 from each other is referred to as the second drainage region II. In this case, the forming region extends at least over the first drainage region I, and preferably also over a large part of the second drainage region II, in particular to the separating suction device 12. In the region of the common belt guide, ie double belt zone 3, a drainage device 14 is provided, which at least one Entwässerungsleiste 16, preferably a plurality of these covers. This is or are arranged in the second dewatering area 11, that is to say between the outlet A of the endless belts 5, 6 on the forming roller 8 and the separating suction device 12.

The FIG. 1a illustrates an embodiment with two endless belts 5 and 6, which are designed for example in the form of Entwässungssiebbändern 17 and 18 and form a twin-wire zone. Depending on the design, these can be designed differently with regard to their drainage performance and can also have, within a drainage band 17 and / or 18 zones, different drainage performance. The leadership of the fiber suspension S is thus carried out between the two dewatering belts 17 and 18 even after the forming roller 8, wherein the separation in the region of the Trennsaugeinrichtung 12 takes place. The Trennsaugeinrichtung 12 is here associated with the first endless circulating belt 5. The arrangement takes place within the loop formed by the first endless belt 5. The first belt 5 carries the resulting fibrous web F on to the next process step, for example by transfer to a felt belt. According to the first embodiment, the drainage strips 16 are associated with only one band, here by way of example the first endless circulating screening belt 5. Preferably, several, a Entwässerungsleistenanordnung 15.1 forming drainage strips 16.1 are provided. This is effective on the inner side 13 of the first endless circulating belt 5. The individual dewatering strip 16.1 causes an additional pressure pulse on the first endless circulating belt 5 and The individual dewatering strip 16.1 can be designed as a rigid strip, as shown by way of example, or spring-mounted or in terms of their contact pressure on the inner side 13 of the first endless circulating Bandes 5 can be variably adjusted. These possibilities will once again be exemplary in FIG. 3 explained. The arrangement of the Entwässerungsleistenanordnung 15.1 takes place before the Trennsaugeinrichtung 12 in the running direction of the dewatering screen belts 17 and 18 considered.

Furthermore, it is conceivable to make the arrangement of the at least one dewatering strip 16 alternatively in the other second endless belt 6. This is in FIG. 1b illustrated by way of example with reference to a section of a machine 1 for the production of tissue webs, in particular the former 2. The FIG. 1b illustrates an embodiment according to FIG. 1a with the arrangement of at least one dewatering strip 16.2, preferably a dewatering strip arrangement 15.2, comprising a plurality of dewatering strips 16.2 spaced apart in the strip running direction and preferably extending over the entire strip width in the second endless circulating belt 6. The basic structure corresponds to that in FIG FIG. 1a Therefore, the same reference numerals are used for the same elements. Again, the two endless belts 5 and 6 are exemplified as Entwässerungssiebbänder 17 and 18. The dewatering strip 16.2 is doing on the inside 19 of the second endless circulating belt 5, in particular dewatering belt 18, effective. These can be designed either as a rigid bar, spring-mounted bar or variable in terms of their contact pressure on the belt 6 dewatering strip 16.2. With regard to the possible embodiments is also on the embodiments in FIG. 3 directed.

Due to the arrangement of additional drainage strips 16.1 or 16.2 upstream of the separating suction device 12 in the region of the double belt zone 3, in embodiments with two sieve belts 17, 18 of the twin-wire zone, a pressure can additionally be built up and thus the fibrous suspension or web is formed and / or dehydrated. The arrangement of the bands 5, 6 and the assignment and location of the drainage strips to these determines the direction of drainage.

Clarify the FIGS. 1a and 1b by way of example, an embodiment of a double belt area 3 made up of two endless circulating belts 5 and 6, which are designed as drainage screen belts 17 and 18, is illustrated FIG. 2a an embodiment according to the invention with a first endless circulating belt in the form of a felt belt 20 and a second endless circulating belt 6 in the form of a Entwässungssiebbandes 18. The remaining structure corresponds substantially to that in the FIGS. 1a and 1b Therefore, the same reference numerals are used for the same elements. Again, a Trennsaugeinrichtung 12 is provided, wherein in the second drainage area II also a drainage device 14, comprising at least one drainage strip is arranged. In the illustrated case, the drainage device 14 comprises two Entwässerungsleistenanordnungen 15.1 and 15.2, wherein the first Entwässerungsleistenanordnung 15.1 associated with the felt belt 20 and on the inside 13 is effective and exemplarily only comprises a drainage bar 16.1. The second Entwässerungsleistenanordnung 15.2 is associated with the second endless circulating belt 6 in the form of Entwässungssiebbandes 18 and includes a plurality of drainage strips 16.2. The first and second dewatering strips 16.1, 16.2 are arranged offset to one another in the axial direction with respect to the strip running direction, that is, a first dewatering strip 16.1 or the first dewatering strips 16.1, for example within the axial distance between the two adjacent dewatering strips 16.2 of the second dewatering Strip assembly 15.2 are arranged in the second endless circulating belt 6. Preferably, the second dewatering strips 16.2 are mounted on a common support device 21.2. This may be a pan. Further conceivable is a suction box 22 in the form of a bottom wire suction box. The individual dewatering strips 16.2 are mounted in the support element 21.2 or the suction box 22. The storage can be either rigid, but preferably elastic, in particular resilient or via means for the variable adjustment of a contact pressure on the individual or the majority of the drainage strips, which are preferably carried out individually controllable. Preferably, at least elastically mounted, most preferably used with regard to the contact pressure variable controllable drainage strips. These can adapt to varying layer heights in different dewatering conditions, wherein the contact pressure of the strips can be kept constant. Depending on the arrangement of the strips to each other and the design of these, the filler content at the individual sides - top and bottom - of the formation can be influenced.

With respect to the execution of the Trennsaugeinrichtung 12 there are a number of possibilities. This can be with a flat surface as in the FIGS. 1a, 1 Bund 2a shown executed or as according to FIG. 2b have a curved active surface. In this case, it is a fixed element, that is, the corresponding on the first endless belt 5, in particular the inner side 13, effective surface 26 is not changeable in their position. In embodiments with a curved surface 26, this offers the advantage that a separation with deflection of the first endless belt 5 can take place without this being damaged on the inside 13, since no edges or corners are provided here, but the decrease in the Area of a curvature takes place. Furthermore, the separating suction device 12 may be characterized by a suction zone 27 which extends over the entire strip width, as in FIG. 1a represented, or as in the Figures 1b . 2a and 2b exemplified by at least two in the belt running direction successively arranged suction zones 27 and 28 to be characterized, the individual zones are preferably individually and variably adjustable in terms of their suction.

The FIGS. 3a and 3b illustrate exemplified possible combinations of the arrangement and storage of the first and second dewatering strips 16.1 and 16.2 of the first and second Entwässerungsleistenanordnung 15.1, 15.2, wherein here according to FIG. 3a the first Entwässerungsleistenanordnung 15.1 two drainage strips 16.1, while the second Entwässerungsleistenanordnung 15.2 three Entwässerungsleisten 16.2. According to FIG. 3b By way of example, at least one such drainage strip 16.1 is assigned to the first endless circulating belt 5, while at least two such drainage strips 16.2 are provided in the second endless circulating belt 6. According to FIG. 3a For example, two drainage strips 16.1 are provided, which are designed as rigid strips, while the drainage strips 16.2 are designed as elastically or resiliently mounted strips which are mounted for example on a designated as a formation box Untersiebsaugkasten 22 via spring means, wherein the suction effect, the drainage performance in addition can be influenced. Instead of Untersiebsaugkastens 22 may also be provided a tub for collecting water. The possibility of storage can also be reversed between the first and the second dewatering strip, that is, not shown here, the second dewatering strips 16.2 can be rigid and the first dewatering strips 16.1 elastically mounted. Preferably, however, an embodiment according to FIG. 3b take place, in which at least one of the drainage strips - first drainage bar 16.1 and / or second drainage bar 16.2 - are variably adjustable in terms of their contact pressure. The FIG. 3b illustrates an embodiment with a rigidly mounted dewatering strip 16.1 in the first endless circulating belt 5 and at least two second dewatering strips 16.2, which are variably adjustable in terms of their contact pressure. These are assigned to means 23, via which the controllability takes place. The controllability 1 of the individual strip preferably takes place individually, so that a different drainage behavior can also be set in the strip running direction. The means comprise for this purpose a pressure medium source 29 and means 24 for adjusting the pressure at the individual drainage bar 16.2. It is also conceivable to carry out the rigid drainage strip 16.1 as a spring-mounted drainage strip 16.1 or the first drainage strips 16.1 perform with variable contact pressure and the second dewatering strips 16.2 rigid or resilient to store, or run the drainage strips both Entwässerungsleistenanordnungen 15.1 and 15.2 variable in terms of their contact pressure. In the latter case, the controllability of both Entwässerungsleistenanordnungen 15.1, 15.2 take place using the same system. As a source of pressure medium, a separate source of pressure medium can be provided or, for example, be resorted to pressure medium sources of other systems in the machine.

The FIG. 3b illustrates a particularly advantageous embodiment, in which the dewatering intensity and the guiding direction of the fibrous web can be actively influenced.

The individual drainage strips 16.1, 16.2 can also be combined with a suction device. Preferably, at least one embodiment is selected in which the drainage strips 16.1 in the first endless circulating belt are fixed with respect to their position relative to the separating suction 12. This will be according to FIG. 4 realized in a constructive embodiment, that the first drainage bar 16.1 or the first drainage strips 16.1 on the separating sucker 12, here in particular the housing 25, are mounted.

With regard to the execution of the drainage strips 16.1, 16.2 itself there are a variety of ways. These are usually designed as ceramic strips, which have an inclined surface, so that they form a wedge when acting on the inside of the respective band 5 or 6 with this.

The length of the second dewatering section in all designs may vary. This depends on the desired drainage behavior and the required drainage facilities to be provided in the form of drainage strips, in particular first drainage strips 16.1 and second Entwässerungsleisten 16.2 and their effect on the between the two endless belts 5 and 6 forming fibrous web.

The in the FIGS. 2 to 4 illustrated embodiments illustrate particularly advantageous embodiments. However, the invention is not limited to these embodiments, in particular with regard to the choice of number, arrangement and storage for the individual drainage strips 16.1 and 16.2 in the two endless belts 5 and 6. It is depending on the desired drainage behavior, a corresponding combination of the individual shown Possibilities conceivable.

The solution according to the invention is also independent of the further processing or the process steps which passes through the fibrous web. It is irrelevant whether the leadership is done after crepe cylinder or by a pressing device. The shaper concept should thus be prefaced as a module of subsequent process steps and thus required devices. The individual bands - first endless circulating belt 5 and second endless circulating belt 6 - are guided over a plurality of guide devices, in particular guide rollers, wherein in roll design of the former in the first endless circulating belt 5, a corresponding Formierwalze is arranged for all common Formierwalzenarten come into consideration.

LIST OF REFERENCE NUMBERS

1

Machine for producing a tissue web

2

molder

3

Double belt zone

4

outer periphery

5

first endless circulating band

6

second endless circulating band

7

dewatering element

8th

forming roll

9

inlet gap

10

headbox

11

Acceptance or separation device

12

Trennsaugeinrichtung

13

inside

14

dehydrator

15.1

first Entwässerungsleistenanordnung

15.2

second Entwässerungsleistenanordnung

16.1

first drainage strips

16.2

second drainage strips

17

Entwässerungssiebband

18

Entwässerungssiebband

19

inside

20

Filzband

21.1

supporting member

21.2

supporting member

22

Untersiebsaugkasten

23

Means for variable adjustment of the contact pressure

24

Means for driving

25

casing

26

area

27

first suction zone

28

second suction zone

29

Pressure medium source

I

first drainage section

II

second drainage section

Claims (13)

1. Machine (1) for producing a tissue web, in particular a tissue machine, comprising a former (2) having two circulating endless belts (5, 6) - a first endless circulating belt (5) and a second endless circulating belt (6) - which form a double belt zone (3), the former (2) being implemented as a roll former, comprising a forming roll (8), around which the two belts (5, 6) partly wrap, forming an inlet (9) for the fibrous suspension (S) that can be introduced from a headbox (10), and a suction separating device (12) for one of the endless belts (5, 6) and a fibrous web (F) formed between the latter, and the suction separating device (12), which acts on the inner side (13) of the first endlessly circulating belt (5) carrying the fibrous web (F) onwards, with which inner side the belt (5) is guided directly on the outer circumference (4) of the forming roll (8), being implemented as a flat suction separator or as a suction separator (12) with a curved surface (26),
   in the double belt zone (3) there being arranged a dewatering device (14) comprising at least one dewatering foil (16.1, 16.2) which acts on one of the two belts (5, 6), and the dewatering device (14) being connected immediately upstream of the suction separating device (12),
   the dewatering device (14) comprising a first dewatering foil arrangement (15.1) assigned to the first belt (5) and having at least one first dewatering foil (16.1), and a second dewatering foil arrangement (15.2) assigned to the second belt (6) and having at least one second dewatering foil (16.2), the first and second dewatering foils (16.1, 16.2), viewed in the axial direction in the belt running direction, in each case being arranged offset in relation to each other, and one of the two endlessly circulating belts (5, 6) being implemented as a dewatering fabric belt (17, 18),
   characterized in that
   the other endlessly circulating belt is implemented as a felt belt (20), the suction separating device (12) being assigned to the felt belt (20) and acting on the inner side (13) of the felt belt (20).
2. Machine (1) according to Claim 1,
   characterized in that
   a plurality of dewatering foils (16.1, 16.2) of a dewatering foil arrangement (15.1, 15.2) is mounted on a common supporting element (21.1, 21.2).
3. Machine (1) according to either of Claims 1 and 2,
   characterized in that
   the dewatering foil arrangement (15.1) assigned to the belt (5) carrying the fibrous web (F) onwards is mounted on the housing (25) of the suction separating device (12).
4. Machine (1) according to one of Claims 1 to 3,
   characterized in that
   the individual dewatering foil (16.1, 16.2) of a dewatering foil arrangement (15.1, 15.2) is mounted rigidly.
5. Machine (1) according to one of Claims 1 to 4,
   characterized in that
   the individual dewatering foil (16.1, 16.2) of a dewatering foil arrangement (15.1, 15.2) is mounted resiliently.
6. Machine (1) according to one of Claims 1 to 5,
   characterized in that
   the contact pressure of an individual dewatering foil (16.1, 16.2) of a dewatering foil arrangement (15.1, 15.2) can be set variably.
7. Machine (1) according to Claim 6,
   characterized in that
   the dewatering foil (16, 16.1, 16.2) can be pressed on hydraulically or pneumatically or mechanically.
8. Machine (1) according to one of Claims 1 to 7, characterized in that
   the dewatering fabric belt (17, 18) is formed with a different fabric permeability.
9. Machine (1) according to one of Claims 1 to 8,
   characterized in that
   the active surfaces of the individual dewatering foils (16.1, 16.2) of an individual dewatering foil arrangement (15.1, 15.2) are arranged in such a way that these describe a flat surface.
10. Machine (1) according to one of Claims 1 to 8,
    characterized in that
    the active surfaces of the individual dewatering foils (16.1, 16.2) of an individual dewatering foil arrangement (15.1, 15.2) are arranged in such a way that these describe a curved surface.
11. Machine (1) according to one of Claims 1 to 10,
    characterized in that
    the individual dewatering foil (16.1, 16.2) can be combined with a suction device.
12. Machine (1) according to one of Claims 1 to 11,
    characterized in that
    the suction separating device (12) comprises at least one suction zone (27).
13. Machine (1) according to one of Claims 1 to 12,
    characterized in that
    the suction separating device (12) has at least two suction zones (27, 28), which can be activated individually, connected after one another as viewed in the belt running direction.

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