Method and machine for producing a dry-laid fibrous web

Abstract

The invention relates to a method and a machine for producing a fibrous web, preferably a tissue, paper, or cardboard web or a nonwoven web, including a low-water raw material preparation of cellulose-containing fibers, preferably fresh fiber pulp in the form of baled material and / or recycled fibers, in order to form individual fibers and / or fiber bundles, wherein the individual fibers and / or fiber bundles are shaped into a flat fiber fabric in an air flow on a forming belt using a dry forming method and are solidified; a fluid, preferably water and / or a water-additive mixture, is applied onto the fiber fabric, preferably the flat fiber fabric; and the fibrous web is dried. The invention is characterized in that an improved suction device (30) is provided having offset suction chambers (32.m.n).

Description

[0001] Method and machine for producing a dry-elected fibrous web

[0002] The invention relates to a method and a machine for producing a fibrous web, preferably a tissue, paper or board web or a nonwoven web, with a low-water raw material processing of cellulose-containing fibers, preferably fresh fiber pulp as bales and / or recycled fibers, into individual fibers and / or fiber bundles; wherein the individual fibers and / or fiber bundles are formed and consolidated in an air stream to form a flat fiber scrim on a forming belt by a dry forming process; and wherein a fluid, preferably water and / or a water-additive mixture, is applied to the, preferably flat, fiber scrim and the fibrous web is dried.

[0003] Devices and methods of this type are known. Document WO 2019 / 137 667 A1 describes a method and a device for producing a fiber mat using a dry-laying process. At the end of the low-water formation of the fibers, a press nip is provided, through which the fiber mat is only briefly passed, to consolidate the fiber mat. The press nip is formed by support elements. To heat the fiber mat, the support elements can be heated directly or indirectly.

[0004] Likewise, the documents DE 1 965 716 A1, EP 0 168 957 A1 or WO 2004 / 065 688 A1 describe methods for drying a fibrous web and dry forming devices with a suction device or a suppression or vacuum housing.

[0005] The document WO 2004 / 065688 A1 describes an improved suction device for improving the uniformity or for specifically influencing the mass distribution of the fibrous web in the machine direction MD and the transverse direction CD by dividing the suction device into evenly distributed, controllable suction chambers.

[0006] A disadvantage of such a design has been shown to be that unevenly formed fiber fabrics or fiber webs with uneven mass distributions or undesirable patterns, such as striping, can still occur in the transverse direction CD and / or machine direction MD.

[0007] To distinguish between the produced fibrous webs, for example a tissue, paper or board web or a nonwoven web, the following distinction is made, which is based on the fiber length, density and fiber weave type.

[0008] A tissue, paper or board web is defined as a fibrous web with predominantly medium fiber lengths, preferably shorter fiber lengths compared to a nonwoven web, of less than or equal to 5 mm, in particular less than or equal to 4 mm, preferably less than or equal to 3 mm, a predominantly bonded structure by hydrogen bonds (OH bridges) and a bulk density of greater than or equal to 0.4 g / cm 3 understood.

[0009] The fibers used in a tissue, paper or board web are additionally characterized by the fact that they have a slenderness ratio of fiber length to fiber diameter of less than or equal to 200, in particular less than or equal to 150, preferably less than or equal to 100.

[0010] A nonwoven web, which also consists primarily of fibers, is defined as a key distinction from a tissue, paper, or board web in that the nonwoven web has a fiber content of between 30% and 50% consisting of very long fibers with an average fiber length of more than 5 mm or continuous fibers, which determine the nonwoven fabric character. Furthermore, the slenderness ratio of fiber length to fiber diameter of a nonwoven web is aimed for at a fiber length-to-fiber diameter ratio of greater than or equal to 300.

[0011] The remaining fiber portion of a nonwoven web can be composed differently and the bulk density should be below 0.40 g / cm 3 in order to classify them as nonwovens.

[0012] Another distinguishing feature between a nonwoven web and a tissue, paper, or board web is the type of fiber bonding. In a nonwoven, the fibers are bonded together by interlocking (e.g., spunlacing or hydroentangling) and / or by cohesion and / or by adhesion. However, nonwoven webs produced using the wet-laid process, which is similar to the papermaking process, are often referred to as nonwoven webs or long-fiber specialty paper webs.

[0013] A machine for producing a fibrous web, preferably a tissue, paper or board web or a nonwoven web, is proposed, comprising a raw material processing plant for the low-water processing of cellulose-containing fibers, preferably virgin fiber pulp in bales and / or recycled fibers, into individual fibers and / or fiber bundles; and a fibrous web plant for dry-forming the fibrous web, and, wherein the fibrous web plant comprises at least one dry-forming device, at least one forming belt, and at least one suction device, wherein the suction device is arranged on an opposite side of the forming belt and the dry-forming device such that the processed individual fibers and / or fiber bundles are formed into a fiber fabric by the dry-forming device and the suction device on the forming belt, and, wherein the suction device comprises at least two suction zones in the machine direction, and,wherein each suction zone is further subdivided in the machine direction into at least two suction chambers in the transverse direction by at least one, in particular physical or virtual, suction chamber wall in the transverse direction. The object of the invention is therefore to provide an improved machine and an improved method for producing a fibrous web with a modified suction device in the dry forming device.

[0014] The machine according to the invention is characterized in that the suction chambers of the suction zone following in the machine direction MD are arranged offset in the transverse direction CD to the suction chambers of the suction zone preceding in the machine direction MD.

[0015] This means that the at least one suction chamber wall of the subsequent suction zone does not directly adjoin the at least one suction chamber wall of the subsequent suction zone.

[0016] The inventors have discovered through investigations that due to the finite expansion of the suction chambers and the necessary suction chamber walls, partition walls or webs, flow-related “dead zones” can form in these areas of the suction device, thus leading to undesired streaking and uneven mass distribution in the produced fibrous web.

[0017] This can result in large deviations of more than + / - 10% in the desired mass distribution in the transverse direction CD. The proposed design allows for maximum deviations of less than or equal to + / - 8%, in particular less than or equal to + / - 4%, and preferably less than or equal to + / - 2%.

[0018] “Staggered suction chambers” means that the suction chamber following in the machine direction MD is arranged partially overlapping or staggered relative to the previous suction chambers.

[0019] This also means that a suction chamber wall in the transverse direction CD between the at least two suction chambers of a preceding suction zone cannot be adjacent to a suction chamber wall in the transverse direction CD between the at least two suction chambers of a subsequent suction zone, but rather is offset in the transverse direction CD by an offset relative to the suction chamber width, in particular relative to the extension in the CD direction. Also, viewed in the machine direction MD, a continuous suction chamber wall cannot be formed over the entire extension of the suction device or over the at least two suction zones in the machine direction MD.

[0020] The suction chamber walls of a subsequent suction zone should also not be in the “slip shadow” of a previous suction chamber wall, so that only a limited or shorter dead zone can form in the machine direction MD than if the entire extension of the suction device in MD is divided by a continuous suction chamber wall.

[0021] To ensure the unambiguous assignment of the suction chambers, the suction device, viewed from the z-direction in a top view, is indexed into a matrix with the two dimensions "m" in the MD direction and "n" in the CD direction. This enables the unambiguous assignment and definition of a subsequent suction chamber in the MD direction with the index "m+1." Furthermore, each characteristic describing the suction chamber can also be implemented with an index.

[0022] A suction chamber is defined by physical or virtual (in an embodiment according to claim 10) suction chamber walls in its dimensions in the MD-CD plane. A suction chamber wall can divide two suction chambers in a suction zone in the transverse direction CD, i.e., oriented essentially in the MD direction or parallel thereto, and a suction chamber wall can form a common boundary for both suction chambers.

[0023] A suction chamber wall in MD, i.e. essentially oriented in the CD direction or parallel to it, can form the boundary between a preceding and subsequent suction zone. Advantageously, by virtue of the suction chambers 32.m+1.n of a subsequent suction zone 32.m+1 being offset, staggered or overlapping in the transverse direction CD with respect to the preceding suction chambers 32.mn of the preceding suction zone 32.m, the dead zones of the suction chamber walls within the suction device can be reduced and an improved fibrous web can be achieved directly after the dry forming device. As already mentioned, the main focus is on evening out the mass distribution in CD of the fibrous web in the dry forming device, since the boundary regions in the suction device formed by the geometric limitations of the suction chambers are specifically distributed over the available fiber deposition area.

[0024] A further disadvantage of the prior art is that, in the case of a suction device with several suction zones in the machine direction MD, the fiber fabric or the fibrous web on the forming belt can continue to exhibit deviations in the deposited mass distribution and / or the thickness in the cross direction CD and thus in the basis weight. This has a particular impact on the two edges of the fibrous web, where, for example, these have a disadvantageous accumulation of fibers and thus an increased mass due to the finite dimension of the dry forming device in the cross direction CD. Firstly, this means that more raw material is used than required and secondly, this excess raw material must be removed again by providing additional devices before the fibrous web is finished. This has a negative impact on the efficiency of the manufacturing process and the necessary complexity of the machine.

[0025] Advantageously, the suction chambers at the edges of the fibrous web in the CD direction have a narrower suction chamber width than the central suction chambers located in the same suction zone. This allows for improved control of the mass distribution in the edge areas in the CD direction of the fibrous web. Another disadvantage is that the required suction power in the individual zones can depend on the raw materials used and the operating parameters; therefore, independent adjustment of the suction device during operation is advantageous.

[0026] Advantageously, the suction zones in the MD direction are divided into further suction chambers in the CD direction. This allows for control of the mass distribution in the CD direction of the fibrous web.

[0027] In an alternative embodiment, the machine is characterized in that at least three, four, five or six suction zones are provided in the machine direction.

[0028] In an alternative embodiment, the machine is characterized in that the at least two suction zones are divided into at least three, four, five or six suction chambers in the transverse direction CD.

[0029] Advantageously, a higher number of suction chambers in the cross direction CD influences the controllability of the cross profile in CD and / or in the machine direction MD and enables a more precise or finer mass cross profile control.

[0030] In an alternative embodiment, the machine is characterized in that the suction chambers have a suction chamber width in the transverse direction and a suction chamber length in the machine direction.

[0031] The suction chamber width of each subsequent suction chamber can be different, preferably smaller, than the previous suction chamber.

[0032] The suction chamber length of each subsequent suction chamber can be designed to be different from the preceding suction chamber, preferably decreasing continuously in the machine direction MD. In an alternative embodiment, the machine is characterized in that the subsequent suction chamber is offset relative to the adjacent, preceding suction chamber by an offset, and that an offset of greater than or equal to 10%, in particular greater than or equal to 20%, preferably greater than or equal to 30%, of a suction chamber width of the preceding suction chamber is provided, and that the offset is related to the nearest suction chamber wall in the transverse direction CD of the preceding suction chamber.

[0033] In an alternative embodiment, the machine is characterized in that at least one further suction zone, preferably at least one first suction zone, is provided and that the at least one further suction zone, preferably the at least one first suction zone, is open or is free of a suction chamber closure device.

[0034] In an alternative embodiment, the machine is characterized in that the suction device feeds air and / or fibers extracted through the permeable forming belt back to the raw material processing plant, preferably after a second defibration device.

[0035] Advantageously, this arrangement enables fiber recovery.

[0036] In an alternative embodiment, the machine is characterized in that the suction device comprises a filter device, preferably a fine filter device, before the air is fed into the raw material processing plant.

[0037] In an alternative embodiment, the machine is characterized by the fact that the suction zones and / or the suction chambers can be independently controlled in terms of their suction power. Advantageously, each suction chamber can be individually adjusted in terms of its suction power, thus enabling continuous regulation of the mass of the deposited or formed fiber fabric in the dry forming device.

[0038] The regulation can be implemented via at least one first control device assigned to each suction chamber. For example, each suction chamber can be connected to its own suction channel and indirectly to an individually adjustable suction fan. It is also conceivable to connect each suction chamber directly to a suction fan.

[0039] However, it is also conceivable in an alternative embodiment that the suction chambers in the machine direction MD and / or in the transverse direction CD are interconnected via a single or multiple suction fans. This then requires a respective second adjusting device. This can be designed, for example, as a closing mechanism or a suction chamber closure device.

[0040] In an alternative embodiment, the machine is characterized in that the at least two suction chambers of the at least two suction zones each comprise a suction chamber closure device.

[0041] Advantageously, each suction chamber can be individually adjusted in its suction power via a suction chamber closure device and thus enables a continuous regulation of the mass of the laid or formed fiber fabric in the dry forming device even with only a single, preferably only constantly operated, suction fan.

[0042] In an alternative embodiment, the machine is characterized in that the suction chamber closure device is designed as a rotatable throttle valve, at least two rotatable louvers, or a perforated, movable double element further comprising a movable perforated element and a stationary perforated element. Advantageously, in its simplest form, the suction chamber closure device is designed as a simple rotatable louver or a rotatable throttle valve. This enables very simple control of the outflowing air. For more precise control, at least two, three, or four rotatable louvers can be provided per suction chamber instead of a single louver.

[0043] When the suction chamber closure device is designed with a lamella design, a shadowed flow area can form directly behind the lamella, which can negatively impact the fibers deposited on the forming belt. This can be avoided by an alternative design of the suction chamber closure device with a perforated, movable double element. Positioning the lamellas deeper below the forming belt can also reduce this effect.

[0044] The perforated, movable double element enables an equally simple control of the suction power of the suction chamber through a minimal displacement in the CD and / or MD direction, which essentially corresponds to the largest perforation opening dimension.

[0045] In an alternative embodiment, the machine is characterized in that the suction chamber closure device is a deformable lip extending across the entire transverse direction, such that the suction chambers are formed in the transverse direction free of physical suction chamber walls. These virtually formed suction chambers have the advantage that no flow-related dead zones can form in the machine direction MD.

[0046] In an alternative embodiment, the machine is characterized in that the transversely extending, deformable lip is made of an easily deformable plastic. In an alternative embodiment, the machine is characterized in that the transversely extending, deformable lip is deformable in the transverse direction by at least two adjusting devices.

[0047] In an alternative embodiment, the machine is characterized in that the suction chamber closure device has a minimum opening of less than or equal to 30%, in particular 20%, preferably 10%, and greater than or equal to 1% of a respective suction chamber area.

[0048] Advantageously, the suction chambers cannot close completely; this always allows a minimal loading of the permeable or semi-permeable forming belt and avoids a holey fiber web.

[0049] In an alternative embodiment, the machine is characterized in that a measuring device, preferably a non-contact measuring device, for basis weight measurement and / or thickness profile measurement in CD and / or MD direction is provided downstream of the dry forming device, and that the suction chambers are controlled in their suction power at least via a signal from the measuring device and a control and regulation system.

[0050] Advantageously, a measuring device is provided with which the thickness distribution or the mass distribution in the MD and / or CD direction of the fibrous web can be measured continuously during operation of the machine during operation of the fibrous web system. From the measured signal, preferably with a signal from the feed of the fibers 209 from the raw material processing system, the required amount of suction power or negative pressure in the suction device and the suction chambers is calculated and adjusted via the control and regulation system. The solution is also achieved by a method for producing a fibrous web, preferably a tissue, paper or board web or a nonwoven web, comprising a raw material processing system for the low-water processing of cellulose-containing fibers, preferably virgin fiber pulp as bales and / or recycled fibers, into individual fibers and / or fiber bundles;and a fibrous web system for dry forming the fibrous web, and, wherein the fibrous web system comprises at least one dry forming device, at least one forming belt and at least one suction device, wherein the suction device is arranged on an opposite side of the forming belt and the dry forming device, such that the processed individual fibers and / or fiber bundles are formed into a fiber fabric by the dry forming device and the suction device on the forming belt, and, wherein the suction device comprises at least two suction zones in the machine direction, which are arranged one behind the other and, wherein the at least two suction zones in the machine direction are further divided into at least two suction chambers in the transverse direction by at least one suction chamber wall in the transverse direction.;

[0051] According to the invention, it is provided that the suction chambers of a suction zone following in the machine direction are arranged offset in the transverse direction (CD) to the suction chambers of a suction zone preceding in the machine direction and that the mass distribution in the transverse direction of the fiber fabric is controlled by regulating a suction power of the suction chambers.

[0052] Offset means that the at least one suction chamber wall in the transverse direction of the subsequent suction zone does not directly adjoin the at least one suction chamber wall in the transverse direction of the subsequent suction zone.

[0053] The invention expressly extends to embodiments which are not given by combinations of features from explicit references to the claims, whereby the disclosed features of the invention can be combined with one another in any way - as far as this is technically reasonable.

[0054] Further features and advantages of the invention will become apparent from the following description of a preferred embodiment with reference to the drawing.

[0055] The invention is explained below with reference to the following figures.

[0056] Fig. 1 shows a schematic representation of a raw material processing plant 2 for the low-water processing of cellulose-containing fibers 200;

[0057] Fig. 2 shows a schematic representation of a fibrous web plant 3 for producing a dry-formed fibrous web 309;

[0058] Fig. 3a shows a schematic plan view of a suction device 30 of a dry forming device 4;

[0059] Fig. 3b shows a schematic side view of a suction device 30 of a dry forming device 4;

[0060] Fig. 4a shows a schematic plan view of a suction device 30 of a dry forming device 4 with an alternative arrangement of suction chambers;

[0061] Fig. 4b shows a schematic top view of a suction device 30 of a dry forming device 4 with a further alternative arrangement of suction chambers. To clarify the individual directions, a higher-level Cartesian coordinate system is created in the figures, which can be used to illustrate the individual directions. The x-direction illustrates the extension in the longitudinal direction, which is also referred to as the machine direction MD (machine direction). The y-direction corresponds to the direction perpendicular to the machine direction and is referred to as the cross-machine direction CD (cross-direction), while the z-direction corresponds to the vertical direction. Figs. 1 and 2 show a possible embodiment of a machine 1 or a manufacturing process 1 in a schematic representation.

[0062] Fig. 1 schematically illustrates a possible embodiment of a low-water processing 2, or a low-water raw material processing plant 2, in which the individual fibers and / or fiber bundles 209, for example from fiber-containing recycled material 200, 50 and / or from fresh fiber pulp 200 as bale product 200, are produced by comminution devices 221, 222, 223 and / or defibration devices 221, 222, 223. After successful comminution or defibration, the individual fibers and / or fiber bundles 209 are fed to an air stream 30, 90, and the air / fiber mixture is fed via one or more distribution channels to a fiber web plant 3, shown in Fig. 2, for producing a dry-formed fiber web 309.

[0063] A parallel arrangement of several raw material processing plants 2, which can supply a single fibrous web plant 3, is also conceivable. This is advantageous if a raw material processing plant 2 alone cannot produce the required quantity of individual fibers and / or fiber bundles 209 or if different types of cellulose-containing fibers 200 are used as raw material, for example, for a multi-layer fibrous web 309.

[0064] The low-water processing 2 makes a decisive contribution to the quality and properties of the dry-formed fibrous web 309 produced, as well as to the overall balance of the production process with regard to economic and energetic aspects. For example, one challenge here is to transform a discontinuous into a continuous process, whereby the very high production quantities of several thousand tons of finished fibrous web 309 per year are the key goals.

[0065] These high production volumes mean that the available raw material 200 should ideally be stored as compactly as possible in order to keep storage to a minimum. An important aspect of low-water raw material processing 2 is that the required volume of the processed raw material 200 to 209 increases steadily until final processing in the fiber web plant 3. The increase in volume can typically range from 30,000 to 50,000 times between the fresh fiber pulp in bale form 200 and the individual fibers and / or fiber bundles 209 dissolved in the air stream. Therefore, storage or intermediate storage 240 in the raw material processing process 2 should be kept as low as possible and only provided for the crucial processing steps.

[0066] Another aspect of the overall balance is keeping the raw material input high in terms of availability and low in terms of cost. For example, virgin fiber pulp 200 can be delivered in the form of more costly and bulky rolls instead of bales. A bale can consist of several sheets or shreds of virgin fiber pulp.

[0067] Due to the widespread use of fresh fibre pulp in the form of rolls for end products, the term fluff pulp (“fluff pulp” or cellulose wadding) has become colloquially synonymous with fresh fibre pulp from rolls. However, this is not correct, since only shredding the rolls can produce fluffed pulp.

[0068] Usually, in the case of virgin fiber pulp in the form of rolls, a large part of the raw material preparation for the produced fiber web is already shifted into the production process of the virgin fiber pulp, in that more complex and elaborate production processes have to be selected for the production, which can already be coordinated with regard to the composition of the pulp with additives for the production of the final fiber web and, much more importantly, place lower tolerances on the mass distribution of the roll goods compared to the bale goods, since this is necessary for the known, simplified fiber web production process to provide a continuous mass flow.

[0069] Additives such as debonding agents are usually added to the roll goods to facilitate the dissolution of the fibres and prevent them from accumulating again during the further production process. This is usually not the case in baled goods or is reduced to a minimum.

[0070] Furthermore, compared to rolls, virgin fiber pulp in bale form is characterized by a smaller storage volume and a lower fiber concentration or fiber quantity per cubic meter of volume. Typically, in a low-water raw material processing plant, this refers to the concentration of fibers, air, and possibly other dissolved substances and / or additives. For example, virgin fiber pulp in bale form has a fiber concentration of essentially 99-100%, or in other words, one cubic meter of volume is filled with 600 kg of virgin fiber pulp in bale form, sheets, or shreds. Virgin fiber pulp in roll form, on the other hand, has a lower fiber concentration of around 50% per cubic meter of volume.

[0071] The concentration or substance density usually describes the amount of undissolved material in a fiber suspension, but here it is understood as the amount of fiber material or other substances dissolved in one cubic meter of air.

[0072] The bale and roll shapes usually have similar material densities of around 600 kg / m 3 However, the roll form, due to its cylindrical shape, typically requires more than twice the storage volume to store the same amount of virgin fiber pulp. The lower volume allows for optimized transport chains and storage, which is necessary for producing a competitive fibrous web with large target quantities per day or per year.

[0073] In this context, the usual simplification is adopted, equating roll material with fluff pulp. Coupling the two production processes of the low-water raw material processing 2 and the fiber web plant 3 is an important component for the production of high-quality fiber webs 309, both of which can be coordinated, controlled, and regulated via a higher-level control and regulation device 60.

[0074] The low-water raw material processing process 2 or the raw material processing plant 2 is characterized by a multi-stage comminution 221, 222, 223 of the discontinuously supplied raw material 200, wherein at the end of the low-water raw material processing process 2, an air flow with dissolved individual fibers and / or fiber bundles 209 can be continuously provided to the downstream fibrous web plant 3, tailored to the water-reduced raw material processing process 2. The low-water raw material processing process 2 or the raw material processing plant 2 and the downstream fibrous web plant 3 are free of any intermediate storage of the individual fibers 209 connected between the plants and are thus made available to the fibrous web plant 3 "on demand."

[0075] The generic term "raw material 200" is used for cellulose-containing fibers 200, preferably virgin fiber pulp in bale form 200 and / or recycled fibers 200, 50. The recycled fibers can, on the one hand, arise from the fiber web plant 3 itself as very high-quality recycled virgin fiber pulp 50, and / or it can also be intended that recycled material from waste paper be used to further improve the overall balance of the manufacturing process.

[0076] The discontinuously supplied raw material 200 is typically fed as baled goods 200 via conveyor belts 220 to a first comminution device 221. The first comminution device 221, preferably a first shredder 221, is designed such that it can perform a first comminution of the baled goods 200 into coarse shreds 201 or chips 201.

[0077] The chips 201 are then fed to a cleaning device 230, wherein any unwanted components, so-called “rejects,” such as metals, contaminants, and / or packaging residues, still contained in the chips 201 can be filtered out, and cleaned chips 202 are present after the cleaning device 230, preferably designed as a cyclone separator 230.

[0078] These cleaned chips 202 are ideally temporarily stored in a larger storage unit 240, preferably designed as a silo 240 or vertical silo 240. This is advantageously the only larger storage unit 240 in the overall production process 2 of the raw material. A single, larger storage unit 240 is understood to mean that small, micro-storage units can also be created in the individual components of the raw material processing plant 2 due to the construction or design of the components, but these are not suitable for supplying the process for several seconds, preferably minutes.Advantageously, the storage 240 is arranged immediately after the cleaning 230 of the chips 201, whereby the volume increase can be kept as small as possible. In addition, a maximum storage capacity of the storage 240 of greater than or equal to 30 minutes, in particular greater than or equal to 60 minutes, preferably greater than or equal to 90 minutes, and less than or equal to 120 minutes of production of the fibrous web system 3 is provided. The size of the storage 240 thus depends on the produced basis weights and width of the fibrous web 309 and the production speeds of the fibrous web system 3. The design of the storage 240 is geometrically optimized, so that a compact, low-air, volume-optimized storage of the cleaned chips 202 is enabled.

[0079] Alternatively, a conditioning device 260 or a conditioning 260 of the cleaned chips 202 can be provided after the cleaning 230 of the chips 201 and before the storage 240 for the cleaned chips 202. For example, the conditioning 260 supplies a small amount of moisture to the chips 202, for example, to minimize or prevent dust formation and / or electrostatic charging. If this is provided, applied moisture can have a negative impact on the overall balance, and additives can also be added to the conditioning 260.

[0080] The storage unit 240 is preferably designed as a vertical storage silo 240, wherein the weight of the cleaned chips 202 can advantageously enable a slight compaction. Furthermore, at least one discharge device 241 is provided in the storage unit 240, which can enable continuous discharge of the cleaned chips 202. This discharge device 241 can represent a separate subject matter of the invention.

[0081] To assist the discharge of the cleaned chips 202 from the storage 240, a first air stream 90 is added directly at the outlet of the storage 240, so that the cleaned chips 202 can be distributed and mixed in the first air stream in a subsequent distribution channel and thus very easily transported to the second comminution device 222.

[0082] In an alternative embodiment, a reject originating from the fibrous web system 3, for example, an edge trim, an edge suction, a fiber suction of the fiber fabric 300, or even individual fibers and / or fiber bundles 209 filtered from the ambient air that have not been deposited, can preferably be added as recycled material 50 before the second shredding device 222. This is particularly advantageous if the recycled material does not yet contain any additives and thus meets the specified quality requirements.

[0083] The second comminution device 222 or fiberization device 222 is preferably designed as a first hammer mill 222, wherein the cleaned chips 202 are comminuted or fiberized therein until individual fibers with isolated nodes 205 are formed, which can then pass through a filter device included in the second comminution device 222. In an alternative embodiment, it can be provided that the individual fibers with isolated nodes 205, after leaving the second comminution device 222, are further processed in a fiber processing device 250 into a continuous mass flow of fibers 206, to which a further air flow 90 is then fed, and the continuous mass flow of fibers 206 becomes a high-resolution, continuous mass flow of a fiber-air mixture 207.

[0084] The high-resolution, continuous mass flow of a fiber-air mixture 207 is fed directly to the third comminution device 224 or fiberization device 224, which is preferably designed as a second hammer mill 224. The third comminution device 224 comminsulates or fiberizes the high-resolution, continuous mass flow of a fiber-air mixture 207 until only individual fibers 208, essentially free of knots or with a small proportion of knots, are formed, which can then pass through a filter device included in the third comminution device 223.

[0085] For a further reduction of the individual fiber concentration, a further air stream 90 or, in an alternative embodiment, the exhaust air from a suction device 30 included in the dry forming device 4 is added before the high-resolution individual fibers, essentially free of knots 209, are precisely metered and continuously fed via a distribution system or distribution channels of the fiber web system 3.

[0086] The individual fibers and / or fiber bundles 209 transported by the air stream are fed into a dry forming device 4 of the downstream fibrous web system 3 and distributed uniformly transversely to the machine direction MD of the fibrous web system 3. The individual fibers and / or fiber bundles 209 are deposited in the dry forming device 4, preferably partially by weight, onto a rotating screen 40 or around a rotating forming belt 40 and form a first fiber fabric 300.

[0087] The dry forming step 4 in the dry forming device 4 can be controlled and regulated by at least one control and regulation means included.

[0088] Furthermore, the dry forming device 4 can include a suction device 30, which can support the deposition of the individual fibers 209 on a permeable forming belt 40 and / or can control it as a further control and regulating means.

[0089] Preferably, the first fiber fabric 300 is measured in its mass distribution by an included measuring device 61, preferably a mass measuring device 61 extending in the transverse direction CD, wherein this is used as a controlled variable and coordinated with one another directly via the higher-level control and regulating device 60 in the feed of the individual fibers without knots 209 from the raw material processing plant 2, as well as in the control and regulating means included in the dry forming device 4 and preferably the suction device 30. Preferably, a stationary measuring device 61 extends across the entire web width or is designed such that the entire web width can be measured. Alternatively, the measuring device 61 can also be designed as a traversing measuring device 61, which can move across the web width such that the entire fibrous web width is measured in the transverse direction CD.

[0090] In an alternative embodiment, immediately after leaving the dry forming device 4, the first fiber layer 300 can be controlled and specifically suctioned off excess fibers in the z-direction (thickness) in the transverse direction CD from the surface of the first fiber layer by a suction device 50 arranged in the transverse direction CD, so that a homogeneous thickness distribution can be established in the CD and MD directions. Alternatively, the suction device 50 can also be designed as an edge strip suction device 50, which specifically suctions off the edge regions of the first fiber layer 300, which often vary greatly in thickness and are different from the main or central region of the first fiber layer 300.Advantageously, this edge strip extraction 50 allows fresh, chemical-free recycled material 50 to be fed directly back into the raw material processing plant 2 immediately after the dry forming device 4, which has a positive effect on the overall balance. Likewise, a clean edge of the fibrous web 309 can be produced, which can make further edge trimming before a final reeling 12 of the final fibrous web 309 obsolete.

[0091] Downstream of the dry forming device 4, at least two application devices 7 are provided, which can apply or apply a fluid, preferably a water and / or a water-additive mixture, to the first fiber fabric 300. A first application device 71 and preferably a second application device 72, 73, 74 are provided.

[0092] Furthermore, at least one consolidation device 8 is provided downstream of the dry forming device 4, which can consolidate and preferably structure the first fiber fabric 300. In an alternative embodiment, two, three, or four consolidation devices 8 can be arranged, which successively consolidate and / or structure and / or heat the fiber fabric or fibrous web. The individual press nips can each be formed by their own press rolls or can be combined in a multiple press roll arrangement.

[0093] The application devices 71, 72, 73 are preferably designed as nozzle applicators, which can spray the fluid 70 in the form of a spray jet as fluid droplets 70 onto the fiber fabric 300, 305. Alternatively, the application devices can also be designed such that the fluid is applied in the form of drops, foam, mist, or vapor.

[0094] Alternatively, a curtain applicator or a roller applicator 74 can also be provided, wherein the roller applicator 74 can advantageously be integrated into the consolidation device 8 and, via an application means 741, coats the press roller 81 with a fluid, which then transfers the fluid to the fiber fabric 300 in the following press nip.

[0095] Furthermore, in an alternative embodiment, a pre-consolidation device 6 can be arranged after the dry forming device 4 and before the first application device 71.

[0096] To complete the continuously produced fibrous web 309, a web-wide reel 12 is provided at the end.

[0097] Immediately before the winding 12 of the fibrous web 309, the fibrous web is dried by a drying device 10, preferably a contactless, electrical drying device 10. The contactless drying device 10 can be designed, for example, as a hot air drying device 10, a through-air drying hood 10, or a TAD drying device 10.

[0098] Alternatively, the drying device 10 can also be designed, for example, with infrared elements.

[0099] Advantageously, a contactless drying device 10 can maintain the properties of the fibrous web 309 with regard to its thickness, its feel properties and its absorbency.

[0100] Due to the low total moisture content, the length of the drying device 10 can be kept very compact compared to the usual drying sections from the wet-laying process, thus significantly reducing the total length of the fibrous web system 3 and infrastructure costs. Compared to the usual dry forming process 4, the further reduced total amount of moisture-increasing fluids used also shows an advantageous reduction in the drying devices 10.

[0101] In an alternative embodiment, at least one further heating step 8 of the laid fiber web 300 can be provided before the drying device 10. This further heating step 8 can, for example, be integrated into the consolidation device 8 by heating the press roller 81 and / or the pressing element 82 provided for consolidation. Heating of less than 250°C, in particular less than or equal to 100°C, preferably less than or equal to 80°C, is advantageous because the heating supports the penetration depth of a fluid, preferably water, applied in a first application step 71 into and its distribution in the fiber web 300, which can simultaneously result in more efficient consolidation 8 and / or structuring 8. In the temperature specifications, the temperature refers to the temperature of the heating elements used, which act on the fibrous web orThe temperature introduced into the fibre fabric can be lower.

[0102] In the case of a structuring 8, the press roller 81 is designed as a structured press roller 81 with a surface structure.

[0103] The first application device 71 is arranged directly upstream of the solidification device 8. Furthermore, the first application device 71 applies a fluid, preferably normal water, which means that the water is free of artificial or chemical additives.

[0104] Alternatively, it can also be provided that the first application device 71 applies a fluid, preferably a water-additive mixture. If a water-additive mixture is applied to the fiber web 300 before consolidation 8, the additive is selected from the group of dry strength agents, for example, a starch, to increase the strength in a dry state of the produced fibrous web 309. The dry strength agents are also suitable for application before consolidation, since they have a lower tendency to stick than adhesives or wet strength agents.

[0105] The application devices 71, 72, 73 are designed such that the fiber fabric 300 can be wetted with the fluid over its entire surface. "Overall" means that the fluid is applied over the entire width or across the entire transverse direction CD of the fiber fabric.

[0106] In an alternative embodiment, a vacuum box 31 can be arranged on the respective opposite side of the first, second and third application devices 71, 72, 73, the side of the fiber fabric 300 which is to be wetted, which vacuum box 31 sucks in ambient air through the fiber fabric 300 and a permeable support element 40, 41 or a forming belt 40 on which the fiber fabric 300 is supported, by means of a negative pressure applied, preferably during the application.

[0107] This advantageously enables a controllable application during the application of a fluid with regard to, for example, a greater penetration depth of the applied fluid into the fiber fabric 300 or a control of the quantities in the transverse direction CD and / or machine direction MD.

[0108] Optionally, at least one moisture measuring device 63 can be included in the fibrous web system 3, which can measure the applied fluid on or in the produced fibrous web 300 or 305 before or after the drying device 10. Preferably, the moisture measuring device 63 is arranged such that it can measure before or after the drying device 10.

[0109] Alternatively, a moisture measuring device 63 can also be provided immediately after each application device 71, 72, 73, 74.

[0110] The moisture measuring device 63 can be stationary or traversing. Furthermore, the moisture measuring device 63 can also be suitable for measuring other fibrous web properties such as mass, thickness, formation, opacity or other properties. The fibrous web system 3 is designed for a high, continuous production speed of greater than or equal to 150 m / min, in particular greater than or equal to 250 m / min, preferably greater than or equal to 400 m / min. The width of the continuously produced fibrous web can be greater than or equal to 0.5 m to less than or equal to 10 meters, depending on the operator's requirements. For example, in the case of tissue machines, it is advisable to design them as "single width" or "double width" as is available on the market, which usually corresponds to a width of approximately 3 m for a "single width" version.

[0111] This dimension in combination with the typically produced basis weights of greater than or equal to 5 g / m 2 less than or equal to 200 g / m 2 , preferably greater than or equal to 10 g / m 2 less than or equal to 80 g / m 2 , contribute directly to the required raw material quantity, storage volume, transport capacities and transport routes, and illustrate the importance of the proposed process for the need for a cost-effective raw material processing plant 2.

[0112] 3a and 3b show a possible embodiment of the suction device 30 arranged below, particularly with respect to the vertical direction z, the forming belt 40 and the dry forming device 4. Fig. 3a shows a plan view of the suction device 30 below the permeable forming belt 40, wherein the suction device 30 is divided into at least two, preferably several, suction zones 32.m in the machine direction MD. Fig. 3a is shown as an example with six suction zones 32.1 to 32.6.

[0113] The suction zones 32.m are further subdivided in the cross-machine direction CD such that individual suction chambers 32.mn are formed. By way of example, the six suction zones in MD 32.1 to 32.6 are each subdivided into three or four suction chambers in CD 32.1.1 to 32.6.4. The indices m and n serve to identify the suction zones and suction chambers in their arrangement in the suction device 30. Each suction zone or each suction chamber 32.mn is defined by an extent in the machine direction MD and an extent in the cross-machine direction CD, wherein the suction chamber extent in MD is represented by the reference symbol 32M and the suction chamber extent in CD by the reference symbol 32C.

[0114] At least one, preferably each, suction chamber 32.mn further comprises at least one suction chamber closure device 34, 34a, 34b, 34c, 34d which, for the sake of clarity, are shown only as examples in the suction chambers 32.1.1, 32.1.2 and 32.1.3 as suction chamber closure device 34a, in the suction chamber 32.5.2 as suction chamber closure device 34b and in the suction chambers 32.4.2 and 32.4.3 as suction chamber closure device 34c.

[0115] In the suction chamber closure device shown with reference numeral 34a, the suction chamber closure device 34a is designed as a rotatable throttle valve 34a, wherein the rotatable throttle valve 34a in the suction chamber 32.1.2 is further closed than the two rotatable throttle valves 34a located in the same opening in the suction chambers 32.1.1 and 32.1.3.

[0116] In the suction chamber closure device shown with reference numeral 34b, the suction chamber closure device 34b is designed with at least two rotatable slats 34b, wherein the mode of operation is similar to the design with rotatable throttle valve 34a, but the overall height can be reduced by the distribution over several slats.

[0117] In the suction chamber closure device illustrated by reference numeral 34c, the suction chamber closure device 34c is designed as a perforated, displaceable double element 34c, wherein the perforated, displaceable double element 34c is more closed in the suction chamber 32.4.2 than in the suction chamber 32.4.3, wherein in the suction chamber 32.4.3 both elements are positioned congruently in their perforation, preferably openings or bores in the form of an elongated hole, an elliptical shape or a circular shape, and thus the suction chamber closure device 34c is fully open.

[0118] A possible displacement direction of at least one element of the double element 34c, preferably the upper and / or lower element, is indicated by a double arrow in the MD direction. A displacement direction (not shown) in the CD direction or in any directional vector in the MD-CD plane is also conceivable.

[0119] In the suction chamber closure device illustrated by reference numeral 34d, the suction chamber closure device 34d is designed as a deformable lip 34d extending across the entire transverse direction CD, such that the suction chambers 32.6.n are formed transversely free of boundary walls in the transverse direction CD. Advantageously, in this embodiment, the dead zones can be further optimized, since a continuous adjustment and regulation of the suction power in the CD direction is adjustable.

[0120] In an alternative embodiment, the machine is characterized in that the deformable lip 34d extending in the transverse direction CD is made of an easily deformable plastic.

[0121] In an alternative embodiment, the machine is characterized in that the transversely extending, deformable lip 34d is deformable in the transverse direction CD by at least two adjusting devices 62.

[0122] The suction chamber closure devices 34 allow each suction chamber 32.mn to be individually adjusted in its suction power via the associated suction chamber closure device 34. The suction chambers are connected to at least one suction generating device 53. Alternatively, each suction chamber 32.mn can be connected to its own suction generating device 53; furthermore, it is conceivable that each suction zone 32.mn is assigned its own suction generating device 53. The suction generating device 53 itself can serve as a further control or regulating means.

[0123] Each suction chamber closure device 34 is designed with an actuator 62, which, via the higher-level control and regulating device 60, controls and regulates the suction power of the at least one suction generation device 53 and / or the suction chamber closure devices 34 via at least one actuator 62 based on available data, such as the data from the dry forming device 4 and / or a thickness measuring device 61. Preferably, the suction power is controlled and regulated in such a way that a uniform thickness profile in the z-direction of the fibers 209 deposited on the forming belt 40 without knots or of the fiber layup 300 in the cross-machine direction CD and machine direction MD is established after exiting the dry forming device 4.

[0124] The suction chambers 32.mn are arranged offset in the cross-machine direction CD to the respective preceding suction zone 32.(m-1).

[0125] The suction chambers 32.mn can be designed in different suction chamber lengths 32M and suction chamber widths 32C.

[0126] The cross section through the suction device 30 shown in Fig. 3b shows, in addition to the details just described, a section through any suction chamber row n, wherein the suction chamber closure devices 34 are shown in different open positions.

[0127] Fig. 4a shows a possible alternative embodiment of the suction device 30 arranged below the forming belt 40 and the dry forming device 4. It shows a plan view of the suction device 30 below the permeable forming belt 40, wherein the suction device 30 is divided into six suction zones 32.1, 32.2, 32.3, 32.4, 32.5, 32.6 in the machine direction MD. Fig. 4a shows that the first suction zone 32.1 comprises only one suction chamber 32.1.1 and that the suction chamber 32.1.1 is free of a suction chamber closure device 34 or is open. This first open, undivided suction chamber 32.1.1 advantageously provides a first basic suction power, which, together with the second suction zone 32.2, which is divided into three suction chambers 32.2.1, 32.2.2, 32.2.3 and has suction chamber closure devices 34, forms a suction zone 32.2 that can be regulated and controlled in the transverse direction.

[0128] The inventors have recognized as a further optimization that a stochastic distribution of the suction chambers can be advantageous, in which case the offset, length 32M and width 32C of the suction chambers should be selected such that no repetition pattern or "natural frequency" can form through the suction chamber walls 35, 36 in the machine direction MD, i.e. in combination with the machine speed or movement speed of the fiber fabric in MD, which can have a negative effect on the quality of the produced fibrous web 309, for example due to streaking.

[0129] To illustrate a "staggered" arrangement without a repeat pattern, a variant was shown in Fig. 4a, wherein the suction chambers or the suction chamber walls 35 in CD are arranged offset in such a way that, on an imaginary, dashed line 37 in the machine direction MD, no suction chamber wall of one of the subsequent suction chambers is arranged or partially overlapped or lies in the slipstream of the previous suction chamber wall, respectively, of the first or preceding suction chamber wall 35 in CD.

[0130] In the illustrated embodiment, it is possible for no suction chamber wall 35 in CD following in the machine direction MD to be in the slipstream or on the imaginary line 37 of a suction chamber wall 35 in CD preceding in the machine direction MD. This can be achieved by adjusting the suction chamber length 32M and the suction chamber width 32C or the offset 33. Alternative embodiments are also conceivable in which the suction chamber width 32C becomes constantly smaller or constantly larger in the machine direction MD.

[0131] It may also be conceivable that a second further suction zone 32.1 is arranged between the at least two suction zone suction chamber closure devices 34, which is free of a suction chamber closure device 34.

[0132] Fig. 4b shows a possible further alternative embodiment of the suction device 30 arranged below the forming belt 40 and the dry forming device 4. It shows a plan view of the suction device 30, below the permeable forming belt 40, wherein the suction device 30 is divided into six suction zones 32.1, 32.2, 32.3, 32.4, 32.5, 32.6 in the machine direction MD and each suction zone has three suction chambers 32.m.1, 32.m.2, 32.m.3 in CD within each suction zone, thus forming 18 suction chambers.

[0133] Three alternative embodiments 35.1, 35.2, 35.3 of a suction chamber wall 35 in the transverse direction CD are also shown. The shape of the suction chamber wall can further reduce the flow-related dead zones and additionally contribute to the homogenization of the transverse mass distribution of the fibrous web.

[0134] If the design is to be simple, one type of suction chamber wall shape is used throughout the suction device 30. However, it is also conceivable to use all three shapes shown in a combination, as shown. A straight embodiment 35.1 of the suction chamber wall 35 used in the previous figures is shown in CD, with the straight shape typically oriented parallel to the machine direction MD.

[0135] Furthermore, a straight shape in rising or falling (relative to the MD-CD plane) embodiment 35.2 of the suction chamber wall 35 in CD can be realized, wherein the dead zone caused by the suction chamber wall can be advantageously divided or distributed in the transverse direction CD.

[0136] Furthermore, a zig-zag or wave-shaped embodiment 35.3 of the suction chamber wall 35 in CD can be provided, which makes it possible to mix and weaken the dead zones within a suction chamber across the transverse direction CD by means of the zig-zag or wave shape.

[0137] All three designs of the suction chamber walls in CD are arranged offset in the subsequent suction zone compared to the previous suction zone.

[0138] For the sake of simplicity, the suction chambers are shown without suction chamber closure devices 34, but may include the previously described variants of the suction chamber closure devices 34.

[0139] To illustrate the "offset" arrangement of the suction chambers, or the suction chamber walls 35, in the transverse direction CD, imaginary, dashed lines 37 are drawn starting from the respective preceding suction chamber wall 35 in the machine direction MD. These essentially represent the area of ​​a "slip shadow" of the preceding suction chamber wall 35, and thus no suction chamber wall should extend continuously from one beginning to one end of the suction device 30 in the machine direction MD. A partial overlap or an arrangement in the slip shadow of a preceding suction chamber wall 35 can occur from a subsequent suction zone onwards, as shown in the suction zone 32.5n and 32.6.n, which is located in the slip shadow of the suction chamber wall 35.1 of the suction zone 32.1.n or 32.2.n arranged three suction zones previously.

[0140] 1 machine

[0141] 2 Raw material processing plant Fibre web plant

[0142] Dry forming device

[0143] Pre-consolidation device

[0144] Application device for a fluid

[0145] Consolidation device

[0146] Drying device

[0147] Rolling up

[0148] Direction of travel

[0149] Suction device of the dry forming device

[0150] Vacuum Box - Application Device . m Suction zone(s) in MD .mn Suction chamber(s) in CD C Suction chamber extension in CD M Suction chamber extension in MD

[0151] Offset

[0152] Suction chamber closure device a rotatable throttle valve b two rotatable louvers c perforated, sliding double element d deformable lip

[0153] Suction chamber wall in CD

[0154] Suction chamber wall in MD imaginary line in MD direction

[0155] Forming belt

[0156] Support element

[0157] Extraction device, preferably edge strip extraction

[0158] Suction generating device

[0159] Control and regulation device

[0160] Mass distribution measuring device

[0161] Actuator

[0162] Moisture measuring device Fluid or fluid drops First application device Second application device Third application device Fourth application device, preferably a roller application unit Application element Press roller

[0163] Press element

[0164] Airflow

[0165] Baled goods, shredded baled goods, chips, cleaned chips

[0166] Single fibers with isolated nodes or shredded chips B Single fibers with isolated nodes or shredded chips, high resolution in a fiber-air mixture Continuous mass flow of fibers Continuous mass flow of fibers, high resolution in a fiber-air mixture

[0167] Single fibers essentially free of knots, low resolution

[0168] Individual fibers essentially free of knots, highly resolved in a fiber-air mixture

[0169] First shredding device, shredder

[0170] Second crushing device, preferably

[0171] Fibre-pulling device, especially the first hammer mill

[0172] Third shredding device, preferably

[0173] Defibrillation device, in particular second hammer mill

[0174] Cleaning device, cyclone

[0175] Air

[0176] memory

[0177] Discharge device

[0178] Fiber processing device 260 Conditioning of the cleaned chips

[0179] 300 fiber fabrics after dry forming device

[0180] 305 consolidated fiber fabric after dry forming device

[0181] 309 Fibrous web

[0182] MD Machine direction

[0183] CD Cross machine direction z Vertical direction

Claims

1. A machine for producing a fibrous web (309), preferably a tissue, paper or cardboard web or a nonwoven web, comprising a raw material processing plant (2) for the low-water processing of cellulose-containing fibers (200), preferably fresh fiber pulp in the form of bales, sheets or shreds (200) and / or recycled fibers (200, 50), into individual fibers and / or fiber bundles (209); and a fibrous web plant (3) for dry-forming the fibrous web (309), and, wherein the fibrous web plant (3) comprises at least one dry-forming device (4), at least one forming belt (40) and at least one suction device (30), wherein the suction device (30) is arranged on an opposite side of the forming belt (40) and the dry-forming device (4), such thatthat the processed individual fibers and / or fiber bundles (209) are formed into a fiber fabric (300) by the dry forming device (4) and the suction device (30) on the forming belt (40), and wherein the suction device (30) comprises at least two suction zones (32.m, 32.m+1) in the machine direction (MD), which are arranged one behind the other, and wherein the at least two suction zones (32.m, 32.m+1) in the machine direction (MD) are further subdivided into at least two suction chambers (32.mn) in the transverse direction (CD) by at least one suction chamber wall (35) in the transverse direction (CD), characterized in that the suction chambers (32.m+1.n) of the suction zone (32.m+1) following in the machine direction (MD) are offset in the transverse direction (CD) to the suction chambers (32.mn) of the suction zone (32.m+1) preceding in the machine direction (MD). m) are arranged., 2. Machine according to one of the preceding claims, characterized in that at least three, four, five or six suction zones (32.1, 32.2, 32.3, 32.3, 32.4, 32.5, 32.6) are provided in the machine direction (MD).

3. Machine according to one of the preceding claims, characterized in that the at least two suction zones (32. m) are divided into at least three, four, five or six suction chambers (32. m.1, 32. m.2, 32. m.3, 32. m.3, 32. m.4, 32. m.5, 32. m.6) in the transverse direction (CD).

4. Machine according to one of the preceding claims, characterized in that the subsequent suction chamber (32.m+1.n) is offset by an offset (33) with respect to the adjacent, preceding suction chamber (32.mn) and that an offset (33) of greater than or equal to 10%, in particular greater than or equal to 20%, preferably greater than or equal to 30%, of a suction chamber width (32C) of the preceding suction chamber (32.mn) is provided and that the offset (33) is related to the nearest suction chamber wall (35) in the transverse direction (CD) of the preceding suction chamber (32.mn).

5. Machine according to one of the preceding claims, characterized in that at least one further suction zone (32. m), preferably at least one first suction zone (32.1 ), is provided and that the at least one further suction zone (32. m), preferably the at least one first suction zone (32.1 ), is open or is free of a suction chamber closure device (34).

6. Machine according to one of the preceding claims, characterized in that the suction device (30) feeds air and / or fibers extracted by the forming belt (40) back to the raw material processing plant (2), preferably after a second defibration device (223).

7. Machine according to one of the preceding claims, characterized in that the suction zones (32.m) and / or suction chambers (32.mn) can be regulated independently of one another in their suction power.

8. Machine according to one of the preceding claims, characterized in that at least one, preferably each, suction chamber (32.mn) comprises a suction chamber closure device (34).

9. Machine according to claim 8, characterized in that the suction chamber closure device (34) is designed as a rotatable throttle valve (34a), at least two rotatable slats (34b) or a perforated, displaceable double element (34c) further comprising a displaceable perforated element and a stationary perforated element (34c).

10. Machine according to claim 8, characterized in that the suction chamber closure device (34) is a deformable lip (34d) extending over the entire transverse direction (CD), such that the suction chambers (32.mn) in the transverse direction (CD) are formed free of suction chamber walls (35) in the transverse direction (CD), preferably virtually. 11 . Machine according to claim 10, characterized in that the deformable lip (34d) is made of an easily deformable plastic.

12. Machine according to claim 10, characterized in that the deformable lip (34d) comprises at least two adjusting devices (62) arranged in the transverse direction (CD), so that the deformable lip (34d) is deformable across the transverse direction (CD) in the machine direction (MD).

13. Machine according to claim 8, characterized in that the suction chamber closure device (34) has a minimum opening of less than 30%, in particular 20%, preferably 10%, and greater than or equal to 1% of a respective suction chamber area (32.mn).

14. Machine according to one of the preceding claims, characterized in that a measuring device (61), preferably a contactless measuring device (61), for measuring the mass profile of the fibrous web in the CD and / or MD direction is provided after the dry forming device (4), and that the suction chambers (32.mn) are regulated in their suction power at least via a signal from the measuring device (61) and a control and regulating system (60).

15. A method for producing a fibrous web (309), preferably a tissue, paper or cardboard web or a nonwoven web, comprising a raw material processing plant (2) for the low-water processing of cellulose-containing fibers (200), preferably fresh fiber pulp as bales (200) and / or recycled fibers (200, 50), into individual fibers and / or fiber bundles (209); and a fibrous web system (3) for dry forming the fibrous web (309), and, wherein the fibrous web system (3) comprises at least one dry forming device (4), at least one forming belt (40) and at least one suction device (30), wherein the suction device (30) is arranged on an opposite side of the forming belt (40) and the dry forming device (4), such that the processed individual fibers and / or fiber bundles (209) are formed into a fiber fabric (300) by the dry forming device (4) and the suction device (30) on the forming belt (40), and,wherein the suction device (30) comprises at least two suction zones (32.m, 32.m+1) in the machine direction (MD), which are arranged one behind the other, and wherein the at least two suction zones (32.m, 32.m+1) in the machine direction (MD) are further divided into at least two suction chambers (32.mn) in the transverse direction (CD) by at least one suction chamber wall (35) in the transverse direction (CD), characterized in that the suction chambers (32.m+1.n) of a suction zone (32.m+1) following in the machine direction (MD) are arranged offset in the transverse direction (CD) from the suction chambers (32.mn) of the suction zone (32.m) preceding it in the machine direction (MD), and in that the mass distribution in the transverse direction (CD) of the fiber fabric (300) is controlled by regulating a suction power of the suction chambers.

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