Method and machine for producing a dried fibrous web

Abstract

The invention relates to a method and to a machine for producing a fibrous web, preferably a tissue web, paper web or board web, or a nonwoven web, comprising raw-material preparation, using little water, of pulp fibers, preferably virgin fiber pulp, as bales and / or recycled fibers, to form individual fibers and / or fiber bundles; wherein the individual fibers and / or fiber bundles are formed and solidified in an air stream to form a planar laid fiber scrim on a, preferably permeable, forming belt using a dry forming process; and wherein fluid, preferably water and / or a water-additive mixture, is applied to the, preferably planar, laid fiber scrim, and the fibrous web is dried. The invention is characterized in that the total amount of fluid applied is subdivided among at least two application steps.

Description

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

[0002] The invention relates to a method for producing a fibrous web, preferably a tissue, paper or board web or a nonwoven web, comprising the following steps: a) Low-water raw material processing of cellulose-containing fibers, preferably fresh fiber pulp in bale form and / or recycled fibers, into individual fibers and / or fiber bundles; b) Forming the individual fibers and / or fiber bundles in an air stream into a flat fiber web on a, preferably permeable, forming belt by a dry forming process; c) First application of a fluid, preferably water and / or a water-additive mixture, to the, preferably flat, fiber web; d) Consolidating the flat fiber web by applying pressure in a press nip; e) Second application of a fluid, preferably water and / or a water-additive mixture, to the, preferably flat, consolidated fiber web;wherein a maximum total amount of the fluid in the first and second application of greater than or equal to 1% and less than or equal to 30%, preferably less than or equal to 20%, of the dry mass of the laid fibrous web is applied;

[0003] The invention also relates to a machine for producing a fibrous web.

[0004] 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, through which the fiber mat is only briefly passed, is provided 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. Furthermore, for example, a dry-laying process and a device for tissue webs that have an aesthetic effect and an improved combination of tear resistance, absorbency, and feel are described in document DE 1 965 716 A1 or the parallel document GB 1 296 840 A in English.For this purpose, fresh fiber pulp is processed in roll form ("fluff pulp") and water, wet strength agents, and starch are advantageously applied to the fiber web at various positions, and then compacted and structured before and afterward. A roller applicator is also advantageously used for the application of additives such as wet strength agents and starch, instead of conventional nozzle applicators.

[0005] The described process demonstrates how the important properties of the produced fibrous web can be influenced in this way, including feel, absorbency, and resilience (i.e., strength). Essential to the process is that the fibrous web receives a sufficiently high moisture content of between 6% and 35%, preferably between 10% and 30%, in the first application step by applying only water, and that additional, undefined amounts of moisture are introduced into the fibrous web during subsequent application steps.

[0006] However, this high moisture content of the fibrous web before the first consolidation, as well as during the entire process, has a negative impact on the overall balance of the process, since the introduced moisture must be removed again at great expense using energy and additional machine components, thus limiting the achievable machine speeds. Likewise, if the moisture content is too high, the properties of the fibrous web can deteriorate again.

[0007] Another disadvantage is the use of currently commercially available additives to increase or improve the properties of the manufactured fibrous webs. On the one hand, these additives have largely been optimized and developed for a wet-laid process for fibrous webs, meaning that the additives can normally develop their full properties at high moisture contents in the fibrous web during the manufacturing process. On the other hand, the use of additives is highly controversial with regard to the ecological footprint of the manufactured fibrous web. For example, in addition to the poorly degradable chemical components, thermoplastics are also used, which also require high energy consumption to cure and also contribute to the global challenge of microplastics.

[0008] In the current climate policy situation, it is therefore important to keep the ecological footprint as small as possible by significantly reducing the resources used, such as energy and fresh water, as well as the additives used, especially chemical additives.

[0009] This means that the proposed manufacturing process and the proposed machine operate within a very challenging, narrow corridor regarding the functionality of the resources used, preferably energy and water, and the additives with regard to the achievable properties of the fibrous web and the overall energy balance of the manufacturing process.

[0010] 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.

[0011] 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 The fibers used in a tissue, paper, or board web are additionally characterized by having a fiber length-to-fiber diameter ratio of less than or equal to 200, in particular less than or equal to 150, preferably less than or equal to 100.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] The object of the invention is therefore to provide a device and a method for producing a fibrous web at a high production rate, with lower use of water and additives and at the same time with high mechanical strengths and quality factors such as the feel and the absorption rates.

[0016] According to the invention, a method for producing a fibrous web is proposed, which is characterized in that in the first application step c), an amount of the fluid, preferably water and / or a water-additive mixture, in the range of greater than 1%, in particular greater than 10%, preferably greater than 15%, and less than 30%, in particular less than 25%, preferably less than 20%, of the maximum total amount of the fluid is applied to the preferably flat, consolidated fiber web; and in that in the second application step e), an amount of the fluid, preferably water and / or a water-additive mixture, in the range of greater than or equal to 70%, preferably greater than or equal to 75%, and less than or equal to 99%, in particular less than or equal to 90%, preferably less than or equal to 85%, of the maximum total amount of the fluid is applied to the preferably flat, consolidated fiber web.

[0017] For energy and environmental reasons, the maximum amount of applied fluid, liquid, or moisture is strictly limited throughout the entire manufacturing process, capped at less than or equal to 30% of the dry mass or dry basis weight of the produced fibrous web. The challenges resulting from this constraint are to maintain sufficiently high strength of the fibrous web while maintaining equally high or even better properties in terms of, for example, feel, absorbency, and appearance.

[0018] One known way to increase strength is to apply sufficient chemical additives to the fiber web. However, this is not without consequences regarding the ecological footprint and is no longer acceptable for many end consumers in many regions of the world, so that a further limitation of the maximum amount of chemical additives added is also set as a goal here.

[0019] An optimization of the dry forming process has produced surprising results for our inventors and has shown that with the inventive design at least the same and better property values ​​of the produced fibrous web can be achieved with a significantly lower use of raw materials and that there are still further adjustment screws to further improve the overall process.Advantageously, the total amount of fluid applied is divided into at least two application steps, preferably three application steps. This is particularly advantageous if the first application step is arranged directly before a, preferably mechanical, solidification step and the second application step, in particular with a water-additive mixture, wherein the additive is an adhesive or a wet strength agent, is only carried out after the, preferably last, solidification step. Preferably, after the last application step, the further process is free of further, preferably mechanical, solidification steps.

[0020] It is also important that the amount of fluid applied in the first application step is significantly lower than in the second application step. The amount of fluid in the first application step is limited to a small amount of less than 30%, in particular less than 25%, preferably less than 20%, based on the total amount of fluid in the manufacturing process, which enables particularly efficient bonding of the fibrous web in the immediately following bonding step.

[0021] This can, for example, be represented in a preferred embodiment with a limitation of the total amount of fluid to less than or equal to 30% in the overall process as follows, so that in the first application step c) a maximum of 20% amount of fluid is applied, this means with a maximum total amount of fluid of 30% of the dry weight of the fibrous web that a maximum of 6% fluid, preferably a maximum of 6% water, and thus a maximum of 6% moisture is introduced into the fibrous web before the consolidation step d), which can significantly increase the efficiency of the immediately following consolidation and, preferably, structuring of the fiber fabric and consequently significantly higher strength values ​​can be achieved with high absorption values ​​than with an otherwise usual higher application amount.The remaining 24% moisture content is applied in the following second, preferably third, application step, preferably as a water-additive mixture. The low fluid quantity of less than 30%, preferably less than 20%, in the first application step c) proves particularly advantageous when considering the ratio of achievable strength to total energy requirement. An optimum has been found in this range, so that increasing the fluid quantities, preferably water quantities, in the first application step c) does not significantly increase the strength values ​​of the fibrous web.

[0022] An application of fluid in the first application step, in particular water and / or water-additive mixture, can also have a positive effect on the static charge of the dried fibrous web, but this can also be achieved by very small amounts of moisture in the environment and thus with application quantities of less than 1% or by other discharge devices which have a lower energetic impact on the process balance.

[0023] It is assumed that this method is particularly advantageous when pure water is used to form very efficient hydrogen bonds in the fiber fabric.

[0024] Advantageously, each application step is followed by a consolidation step, which increases the penetration depth and bonding of the applied fluid with the fiber fabric or fiber web and thus the strength properties of the fiber web.

[0025] It is also advantageous if the first application is applied directly during the consolidation step. This can be done, for example, using a type of roller applicator with application of the fluid to a press roll and the subsequent transfer and simultaneous consolidation of the fiber fabric. The consolidation device can advantageously be designed as a calender, although a simple press nip configuration with two or more rolls is conceivable.

[0026] A vertical arrangement of three or more rollers is also conceivable in which the fiber fabric or fiber web is guided in a meandering manner.

[0027] In an alternative embodiment, the method is characterized in that in the second application step e) after the solidification step d) the applied fluid is a water-additive mixture and that the additive is an adhesive and / or a wet strength agent.

[0028] In an alternative embodiment, the process is characterized in that in the first application step c) before the solidification step d) the additive is a dry strength agent, preferably a starch or sodium carboxymethylcellulose.

[0029] Advantageously, the fluid applied in the first application step c) prior to the consolidation step d) is pure water. This affects the basic strength of the fiber fabric by forming hydrogen bonds during the subsequent consolidation.

[0030] Advantageously, a further application step can be provided in the first application step c) or before a further consolidation step, which applies a water-additive mixture instead of pure water. In this case, a water-additive mixture applied before a consolidation step is designed with an additive such as sodium carboxymethylcellulose (CMC) or starch, especially cationic starch such as maltodextrin. These additives are suitable for regulating the dry strength of the produced fibrous web.

[0031] In an alternative embodiment, the process is characterized in that the fibrous web produced contains an additive content of less than or equal to 6.5%, preferably less than or equal to 5%, in particular less than or equal to 1.5%, of the dry mass of the fibrous web.

[0032] Advantageously, in the second application step e) after the consolidation step d), a water-additive mixture is applied, wherein the additive used after the consolidation step d) is an adhesive and / or a wet strength agent, and wherein this is biodegradable and free from harmful microplastic components, and wherein in addition the total amount of the additive is limited to less than or equal to 6.5%, in particular less than or equal to 5%, preferably less than or equal to 1.5%, of the mass of the fibrous web produced, which has a particularly advantageous effect on the ecological footprint.This poses particular challenges for the adjustment and coordination of the production steps, since a high quantity of adhesives and / or wet strength agents cannot be used, as is usually the case, to achieve the necessary strength values ​​in the produced fibrous web and thus the necessary strength values ​​of the fibrous web can largely only be achieved through advantageous arrangement, designs and targeted use of the production steps.

[0033] The adhesive used can be selected from components of latex, such as ethyl vinyl acetate (EVA), but is not limited to the use of EVA.

[0034] The wet strength agent used can, for example, be selected from components such as amine-epichlorohydrin resins, preferably poly(aminoamide)-epichlorohydrin (PAE) resins. Here, too, use is not restricted to these components. In particular, newly researched components may be used if they become established on the market and exhibit special properties for use in a dry forming process, improved biodegradability, and, for example, low viscosity without the addition of a high proportion of water. Research activities are currently underway and point to a possible new additive, which could represent a separate inventive concept. Combinations of EVA and PAE are also conceivable, with the PAE proportion preferably being significantly lower than the EVA proportion.

[0035] In an alternative embodiment, the method is characterized in that the water-additive mixture contains an additive proportion of less than or equal to 20%, in particular less than or equal to 15%, preferably less than or equal to 11%, and greater than or equal to 5%, in particular greater than or equal to 8%, preferably greater than or equal to 9%. Advantageously, the additive used is a water-soluble additive which, in an alternative embodiment, can occupy a proportion or concentration in the water-additive mixture of between 5% and 20% when dissolved. In conjunction with the consolidation prior to the second application and the small amount of fluid, preferably water, applied in the first application step, a very advantageous penetration depth and distribution of the additives, preferably adhesives and / or wet strength agents, on and in the fibrous web has been found.

[0036] The concentration or proportion of the additive can have a beneficial effect on the penetration depth into the fiber fabric or the fibrous web. The additive proportion is optimally adjusted to the properties of the fibers used and the production or movement speed of the fibrous web during application. However, for low basis weights between 10 g / m 2 and 100g / m 2 of the fibrous web has proven to be very efficient that the additive proportion is contained in a range of 5 to 15%, preferably essentially 10%, in the water-additive mixture.

[0037] It is advantageous to keep the additive content used as low as possible to minimize environmental impact, but as high as necessary to achieve sufficient strength. At the same time, the challenges for the additive used in a dry forming process are greater than in a wet laying process, since there is little to no water content in the fiber fabric into which the additive is applied, whereas in a wet laying process there is usually already sufficient water in the fiber fabric. Thus, the requirements for the dissolution of the additives in the water-additive mixture in a dry forming process are significantly higher than for application in a conventional wet laying process, for which the currently available additives were primarily developed.

[0038] In an alternative embodiment, the method is characterized in that in the second application step e) the fluid is applied to the solidified fibrous web in a surface-covering manner.

[0039] Advantageously, a full-surface application of the fluid is provided in the second application step after a final consolidation. This means that the fluid is applied continuously in the cross-direction (CD) and machine direction (MD) and is thus applied to the compacted high-pressure and low-pressure zones after a previous, full-surface consolidation and structuring of the fibrous web. A full-surface application is particularly advantageous in the less compacted low-pressure zones intended for high absorption capacity, as the produced fibrous web can still absorb a sufficient amount of fluid here, thus increasing its strength during final, wet use and resulting in less abrasion for the user.

[0040] In an alternative embodiment, the method is characterized in that after the second application step e) the fibrous web is produced free from further consolidation.

[0041] Advantageously, in the second application step e), a water-additive mixture, wherein the additive is an adhesive and / or wet strength agent, is applied to the consolidated and structured fibrous web with high-pressure and low-pressure zones, preferably in a surface-covering manner, wherein a major portion of the water-additive mixture can penetrate into the low-pressure zones of the fibrous web and develops a high wet strength.

[0042] This slightly impairs the feel of the fibrous web, but results in significantly improved strength and clean handling by the end user, which is demonstrated by a lower tendency to pill than with application of the fluid only in the high-pressure zones, since the fiber fabric has already achieved sufficient strength due to the strong bonding effect, and the wet strength agent achieves only slight, if not no, increases. Therefore, a surface application is necessary.

[0043] In an alternative embodiment, the device and the manufacturing process are free from further consolidation of the fibrous web after application of a water-additive mixture, preferably a water-wet strength agent or a water-adhesive mixture, since this consolidation can have a detrimental effect on the running properties of the machine. The applied water-additive mixture, preferably adhesive and / or wet strength agent, has a detrimental effect on the service life of any downstream consolidation device, for example, resulting in increased downtime for maintenance and cleaning, and also in a reduction in machine speed, since fibrous webs unintentionally adhering to a downstream consolidation device are entrained, which can then lead to a tear in the fibrous web and thus to a machine downtime.

[0044] In an alternative embodiment, the method is characterized in that the second application step d) is carried out on the same side of the consolidated fiber fabric as the first application step c). Advantageously, the second d) and first c) application steps are carried out on the same side of the consolidated fiber fabric.

[0045] In an alternative embodiment, the method is characterized in that the second application step d) is performed on the opposite side of the consolidated fiber fabric relative to the first application step c). Advantageously, the second application step d) is performed, particularly when there are exactly two application steps, on the opposite side of the consolidated fiber fabric relative to the first application step c). This allows for a uniform distribution of the applied fluid in the z-direction (thickness) of the fiber fabric and can reduce dust generation in the overall manufacturing process.

[0046] In an alternative embodiment, the method is characterized in that a third application step f) is carried out after the second application step e).

[0047] Advantageously, in a third application step f), the amount of fluid applied in the second application step e) is divided between the second and third application steps, ideally a substantially symmetrical division is made, i.e. 50:50.

[0048] However, it can also be advantageous if the quantity is divided higher on one side than on the opposite side, for example 60:40, in particular 70:30, so that a preferred side with higher strength values ​​can be advantageously set for certain types of fibrous web.

[0049] In an alternative embodiment, the method is characterized in that the third application step f) is carried out on the opposite side of the fiber fabric relative to the second application step d). Advantageously, the third f) and second e) application steps are carried out on opposite sides of the consolidated fiber fabric, resulting in fluid being applied to both sides of the fiber fabric.

[0050] A third application step f) is preferably provided if, in the first application step c), the fluid is applied as water, preferably in a smaller amount than in the second application step e), and a water-additive mixture is applied in the second application step e). Preferably, a water-additive mixture is applied in equal amounts on both sides, thus allowing more uniform penetration depths into the fiber fabric to be achieved on both sides, which can consequently also lead to more homogeneous strength properties of the fibrous web.

[0051] In an alternative embodiment, the method is characterized in that the consolidation step d) of the fiber fabric is carried out directly after the first application step c), and in that in the consolidation step d) a pressure of greater than 10 MPa, in particular greater than 20 MPa, preferably greater than 30 MPa, is exerted on the fiber fabric.

[0052] Advantageously, the fiber fabric is only consolidated after the first application of the fluid, preferably with water, since this can increase the consolidation effect and thus lead to increased tear strength and increased extensibility of the fiber web, since this can increase the penetration depth and connection of the applied fluid with the fiber fabric or the fiber web and thus the strength properties of the fiber web.

[0053] In an alternative embodiment, the method is characterized in that in the consolidation step d), preferably and in the structuring, a pressure is applied over the entire surface of the fiber fabric.

[0054] In an alternative embodiment, the method is characterized in that in the consolidation step d) a structuring of the fiber fabric, preferably one that increases strength, is carried out simultaneously, such that a planarly consolidated fiber web with high-pressure and low-pressure zones is formed.

[0055] Advantageously, a structuring of the fiber layup is carried out with the consolidation device, which can have a further strength-enhancing effect, preferably in an increase in the tear strength, on the consolidated fiber layup 305 or the consolidated fibrous web 305. This simultaneous consolidation and structuring is, in comparison to embossing, primarily carried out not for the optical properties of the fibrous web, but rather to achieve the strength properties. It is important for the structuring that the fibrous web is guided on one side through a smooth support element and on the other side through a structured support element, so that a large proportion of the laid fibers in the highly consolidated area are oriented only in the preferred plane, i.e. the plane formed by the machine direction MD and the transverse direction CD, and only in the low, orIn the weakly consolidated area, the fibers can bend out of this plane to achieve the necessary properties in terms of feel and absorption. The fibrous web is thicker in the low-pressure zones than in the more highly consolidated high-pressure zones.

[0056] In an alternative embodiment, the method is characterized in that a pre-solidification step i) is carried out before the first application step e).

[0057] Advantageously, pre-consolidation i) is performed before the first application step c). This allows for the creation of a minimum strength of the fiber fabric before the application of fluid, thus enabling higher application quantities of fluid than without pre-consolidation i) and holds the fibers of the fiber fabric on the permeable forming belt during application. Pre-consolidation i) acts on the fiber fabric across the entire transverse direction CD to create an initial basic strength, compressing and consolidating the thickness of the fiber fabric.

[0058] In an alternative embodiment, the method is characterized in that a distribution and control system and at least one moisture measuring device are arranged after a final application step, preferably after each application step c), e) or f), and that a quantity of the applied fluid is distributed and regulated in each application step by the distribution and control system such that the supplied quantity of fluid, preferably the quantity of water, is adjusted during operation of the machine. Advantageously, at least one measuring device is arranged at least after the final application step, preferably after each application step, for measuring the moisture content of the fiber fabric or fibrous web, wherein a higher-level distribution and control system can adjust the, preferably fully automatic, adjustment of the applied quantities of fluid, preferably the quantity of water, during operation of the machine.

[0059] In an alternative embodiment, the method is characterized in that in the application steps the applied fluid is applied as a spray jet, drops, mist, steam, foam, curtain, and / or via a roller.

[0060] In an alternative embodiment, the method is characterized in that in the application steps the fluid is applied to the fiber fabric from one side, and that on the opposite side the fiber fabric is vacuumed by a vacuum device in such a way that the fluid applied on one side will penetrate deeper into the fiber fabric.

[0061] In an alternative embodiment, the method is characterized in that at least one drying step g) is carried out during the production of the fibrous web, and that the at least one drying step g) dries the consolidated fiber fabric contactlessly by an electrically heated drying device; preferably, the drying device is formed by infrared heating elements or through-air drying hoods.

[0062] The consolidated fibrous web can be supported by a drying wire during the drying step g) or alternatively can be guided through the drying device without support.

[0063] Advantageously, drying step g) is carried out using a contactless drying device, such as infrared elements and / or through-air drying hoods. Contactless drying allows the properties, such as the thickness (bulk) and / or absorbency, of the consolidated fiber fabric or fibrous web to be influenced only slightly or not at all, even during drying.

[0064] In an alternative embodiment, a second, third and fourth drying step of the fibrous web may be provided.

[0065] In an alternative embodiment, the method is characterized in that in the consolidation step d) the press nip is heated and that the fibrous web in the press nip reaches a temperature of 60°C to 250°C, preferably 75° to 150°C.

[0066] Advantageously, in the consolidation step d), the fibrous web is heated such that the fluid, preferably water, applied to the fibrous web or the fiber fabric 300 in the first application step c) solidifies the fiber fabric wetted with liquid fluid, preferably water, in the press nip and is simultaneously heated such that the liquid fluid evaporates on and / or in the fiber fabric and the fluid in vapor form can penetrate further into the fiber fabric under simultaneously applied pressure.

[0067] This requires temperatures in the bonding device, preferably the calender rolls, that are essentially set just slightly, for example, at most 20°C above the evaporation temperature of the fluid, preferably water, applied in the first application step c). The temperature must be adjusted to the machine speed and the residence time in the press nip so that the fibrous web can absorb sufficient heat and the applied fluid can evaporate. When using water as the fluid in the first application step c), temperatures of 60°C to 250°C, preferably 75°C to 150°C, have proven to be optimal with the maximum applied fluid quantities in the first application step c).

[0068] A machine for producing a fibrous web, preferably a tissue, paper or cardboard web or a nonwoven web, in particular for carrying out the method according to the invention, comprising a raw material processing plant for the low-water processing of cellulose-containing fibers, preferably fresh fiber pulp in bale form and / or recycled fibers, into individual fibers and / or fiber bundles; and a fibrous web plant for dry-forming the fibrous web, further comprising a dry-forming device for forming the individual fibers and / or fiber bundles in an air stream into a flat fiber web on a preferably permeable forming belt; a first application device for applying a fluid to the preferably flat fiber web, in particular for applying water; a consolidation device for consolidating the flat fiber web by applying pressure in a press nip;a second application device for applying a fluid to the preferably flat, consolidated fiber fabric, in particular for applying a water-additive mixture;

[0069] According to the invention, the machine is provided with the

[0070] Raw material processing plant for low-water processing and the

[0071] Fibre web plant for dry forming are in operative connection in such a way that the applied quantities of fluid are regulated via a distribution and control system during operation of the machine to the parameters of the raw material processing plant and the fibre web plant.

[0072] It is advantageous to further optimize the applied fluid quantities through control technology, and to regulate and control the applied fluid quantities based on the properties of the raw materials supplied, preferably the raw material moisture content, from the raw material processing plant. This can result in further savings in applied fluid and energy.

[0073] In an alternative embodiment, the machine is characterized in that at least one moisture measuring device is arranged after an application device, in particular after a last application device, preferably after each application device, and that a quantity of the applied fluid in the at least one application device is distributed and regulated by the distribution and control system in such a way that the supplied quantity of fluid, preferably the quantity of water or water additive, is adjusted during operation of the machine.

[0074] In an alternative embodiment, the machine is characterized in that the consolidation device is arranged directly after the first application device, and that the consolidation device is designed such that a pressure of greater than 10 MPa, in particular greater than 20 MPa, preferably greater than 30 MPa, is exerted on the fiber fabric.

[0075] The consolidation step immediately following the first application step can increase the penetration depth and bonding of the applied fluid with the fiber fabric or fiber web and thus lead to increased tear resistance and increased extensibility of the fiber web.

[0076] This combination of bonding and application allows the amount of fluid to be kept low while maintaining or even increasing the fiber web's properties, despite a significantly reduced number of strength-enhancing bonds in the form of hydrogen bonds and / or chemical additives between the individual fibers of the fiber web. This has a particularly beneficial effect on the energy and ecological aspects of the process.

[0077] This allows for the use of fewer raw materials and less energy while maintaining or improving the properties of the produced fibrous web. In particular, the strength-enhancing bonding properties of the applied fluid with the fibers of the fiber fabric can be improved without additional amounts of fluid and other chemical aids.

[0078] Furthermore, it can be provided that the pressing pressure of the solidification device is also controlled and regulated by the control and regulation system depending on the amounts of fluid applied by the application device. The invention expressly also extends to embodiments that are not specified 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 desired way - as long as this is technically reasonable.

[0079] Further features and advantages of the invention will become apparent from the following description of a preferred embodiment with reference to the drawing.

[0080] The invention is explained below with reference to the following figures.

[0081] Fig. 1 shows a schematic representation of a raw material processing plant 2 for the low-water processing of cellulose-containing fibers 200;

[0082] Fig. 2 shows a schematic representation of a fibrous web plant 3 for producing a dry-formed fibrous web 309.

[0083] To clarify the individual directions, a higher-level Cartesian coordinate system has been created in the figures, which can be used to illustrate the individual directions. The x-direction represents the longitudinal extension, also known as the machine direction (MD). The y-direction corresponds to the direction perpendicular to the machine direction and is referred to as the cross-machine direction (CD), while the z-direction corresponds to the vertical direction.

[0084] Fig. 1 and Fig. 2 show a possible embodiment of a machine 1 or a manufacturing method 1 in a schematic representation.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] Additives such as debonding agents are usually added to the roll material to facilitate the debonding of the fibers and prevent them from accumulating again during the further production process. This is usually not the case with baled material or is reduced to a minimum. Furthermore, virgin fiber pulp in bale form is characterized by a smaller storage volume and a lower concentration of fibers or fiber quantity per cubic meter of volume compared to roll form. In the low-water raw material processing plant, this is usually understood to mean the concentration of fibers, air, and possibly other dissolved substances and / or auxiliary materials. 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 600kg of virgin fiber pulp in bale form, tablets, or shreds.Fresh fiber pulp in roll form, on the other hand, has a lower fiber concentration of around 50% per cubic meter of volume.

[0093] 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.

[0094] The bale and roll shapes usually have similar material densities of around 600 kg / m 3However, the roll shape, due to its cylindrical shape, typically requires more than twice the storage volume for 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. Higher demands on the raw material processing plant.

[0095] In this context, the usual simplification is adopted in which roll goods are equated with fluff pulp.

[0096] A coupling of the two production processes of the low-water raw material processing 2 and the fibrous web plant 3 is an important component for the production of high-quality fibrous webs 309, which can both be coordinated, controlled, and regulated via a higher-level control and regulating device 60. 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 fed raw material 200, wherein at the end of the low-water raw material processing process 2, an air stream with dissolved individual fibers and / or fiber bundles 209 can be continuously provided, tailored to the downstream fibrous web plant 3. The low-water raw material processing process 2 orThe raw material processing plant 2 and the following fiber 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 fiber web plant 3 “on-demand.”

[0097] 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.

[0098] 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.

[0099] The chips 201 are then fed to a cleaning device 230, wherein any unwanted components so-called “rejects” still contained in the chips 201, such as metals, contaminants and / or packaging residues, can be filtered out, and after the cleaning device 230, preferably designed as a cyclone separator 230, cleaned chips 202 are present. 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 the design orthe design of the components can result in smaller micro-accumulators, but these are not suitable for supplying the process for several seconds, preferably minutes. Advantageously, the accumulator 240 is arranged immediately after the cleaning 230 of the chips 201, whereby the increase in volume can be kept as small as possible. In addition, a maximum storage capacity of the accumulator 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 accumulator 240 is thus dependent 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 accumulator 240 is geometrically optimized, so that a compact, low-air, volume-optimized storage of the cleaned chips 202 is possible.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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 until individual fibers with isolated nodes 205 are formed, which can then pass through a filter device included in the second comminution device 222.

[0105] 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 to form a continuous mass flow of fibers 206, to which a further air flow 90 is then supplied and the continuous mass flow of fibers 206 becomes a high-resolution, continuous mass flow of a fiber-air mixture 207.

[0106] 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.

[0107] 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.

[0108] 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 rotating, preferably permeable, forming belt 40 and form a first fiber fabric 300.

[0109] 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. 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 control it as a further control and regulation means.

[0110] Preferably, the first fiber fabric 300 is measured in its mass distribution by a 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.

[0111] In an alternative embodiment, immediately after leaving the dry forming device 4, the first fiber fabric 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 fabric by a suction device 50 arranged in the transverse direction CD, so that a homogeneous thickness distribution in the CD and MD directions can be established.

[0112] Alternatively, the extraction device 50 can also be designed as an edge strip extraction system 50, which specifically extracts the edge regions of the first fiber web 300, which often vary greatly in thickness and are different from the main or central region of the first fiber web 300. Advantageously, this edge strip extraction system 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 fiber web 309 can be produced, which can make further edge trimming before a final reeling 12 of the final fiber web 309 obsolete.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 a second application device 72, 73, 74 are provided.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] Furthermore, in an alternative embodiment, a pre-consolidation device 6 can be arranged downstream of the dry forming device 4 and upstream of the first application device 71. To complete the continuously produced fibrous web 309, a web-wide reel 12 is provided at the end.

[0117] 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.

[0118] Alternatively, the drying device 10 can also be designed with infrared elements, for example.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] In the case of structuring 8 in the solidification step 8, the press roller 81 is designed as a structured press roller 81 with a surface structure.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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 permeable forming belt 40 on which the fiber fabric 300 is supported, by means of a negative pressure applied, preferably during the application.

[0127] 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.

[0128] 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 the drying device 10. Preferably, the moisture measuring device 63 is arranged such that it can measure before or after the drying device 10.

[0129] Alternatively, a moisture measuring device 63 can also be provided directly after each application device 71, 72, 73, 74. 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.

[0130] 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, tissue machines can be designed as "single-width" or "double-width" machines, as is commonly available on the market, which typically corresponds to a width of approximately 3 m for a "single-width" version.

[0131] 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, directly contribute to the necessary raw material quantity, storage volume, transport capacity and transport routes, and illustrate the importance of the proposed process for the need for a cost-effective raw material processing plant

[0132] List of reference symbols

[0133] 1 machine

[0134] 2 raw material processing plant

[0135] 3 Fibre web plant

[0136] 4 Dry forming device

[0137] 6 Pre-consolidation device

[0138] 7 Application device for a fluid

[0139] 8 Consolidation device

[0140] 10 Drying device

[0141] 12 Rolling up

[0142] 22 Running direction

[0143] 30 Suction device of the dry forming device

[0144] 31 Vacuum Box - Application Device

[0145] 40 forming belt

[0146] 41 Support element

[0147] 50 Extraction device, preferably edge strip extraction

[0148] 60 Control and regulation device

[0149] 61 Mass distribution measuring device

[0150] 63 Moisture measuring device

[0151] 70 fluid or fluid drops

[0152] 71 first application device

[0153] 72 second application device

[0154] 73 third application device

[0155] 74 fourth application device, preferably a roller application unit application element

[0156] Press roller

[0157] Press element

[0158] Airflow

[0159] Baled goods, shredded baled goods, chips, cleaned chips

[0160] 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

[0161] Individual fibers essentially free of knots

[0162] Individual fibers essentially free of knots, highly resolved in a fiber-air mixture

[0163] First shredding device, shredder

[0164] Second crushing device, preferably

[0165] Fibre-pulling device, especially the first hammer mill

[0166] Third shredding device, preferably

[0167] Defibrillation device, in particular second hammer mill

[0168] Cleaning device, cyclone

[0169] Air

[0170] memory

[0171] Discharge device

[0172] Fiber processing device

[0173] Conditioning of the cleaned chips

[0174] Fiber fabric after dry forming device Consolidated fiber fabric after dry forming device Fiber web MD Machine direction

[0175] CD Cross machine direction z Vertical direction

Claims

1. A method for producing a fibrous web (309), preferably a tissue, paper or cardboard web or a nonwoven web, comprising the following steps: a) Low-water raw material processing (2) of cellulose-containing fibers (200), preferably fresh fiber pulp in bale form (200) and / or recycled fibers (200, 50), into individual fibers and / or fiber bundles (209); b) Forming (4) the individual fibers and / or fiber bundles (209) in an air stream into a flat fiber web (300) on a preferably permeable forming belt (40) by a dry forming process; c) First application (71) of a fluid, preferably water and / or a water-additive mixture, to the preferably flat fiber web (300); d) consolidating (8) the flat fiber fabric (300) by applying pressure in a press nip;e) Second application (72, 73, 74) of a fluid, preferably water and / or a water-additive mixture, to the preferably flat, consolidated fiber web (305); wherein a maximum total amount of the fluid in the first c) and in the second application e) of greater than or equal to 1% and less than or equal to 30%, preferably less than or equal to 20%, of the dry mass of the laid fibrous web (309) is applied, characterized in that in the first application step c) (71), an amount of the fluid, preferably water and / or a water-additive mixture, in the range of greater than 1%, in particular greater than 10%, preferably greater than 15%, and less than 30%, in particular less than 25%, preferably less than 20%, of the maximum total amount of the fluid is applied to the preferably flat fiber web (300); and that; in the second application step e) (72, 73, 74), an amount of the fluid, preferably water and / or a water-additive mixture, in the range of greater than or equal to 70%, preferably greater than or equal to 75%, and less than or equal to 99%, in particular less than or equal to 90%, preferably less than or equal to 85%, of the maximum total amount of the fluid is applied to the preferably flat, consolidated fiber fabric (305).

2. Method according to one of the preceding claims, characterized in that in the second application step e) (72, 73, 74) after the Solidification step d) (8) the applied fluid is a water-additive mixture, wherein the additive is an adhesive and / or a wet strength agent.

3. Method according to one of the preceding claims, characterized in that in the first application step c) (71) before the solidification step d) (8) the applied fluid is a water-additive mixture, wherein the additive is a dry strength agent, preferably a starch.

4. Method according to one of the preceding claims, characterized in that the produced fibrous web (309) contains an additive proportion of less than or equal to 6.5%, preferably less than or equal to 5%, in particular less than or equal to 1.5%, of the dry mass of the fibrous web (309).

5. Method according to one of the preceding claims, characterized in that in the first application step c) (71) and / or in the second application step e) (72, 73, 74) the applied fluid is a water-additive mixture which has an additive content of less than or equal to 20%, in particular less than or equal to 15%, preferably less than or equal to 11%, and greater than or equal to 5%, in particular greater than or equal to 8%, preferably greater than or equal to 9%.

6. Method according to one of the preceding claims, characterized in that in the second application step e) (72, 73, 74) the fluid is applied to the solidified fibrous web (305) in a surface-covering manner.

7. Method according to one of the preceding claims, characterized in that after a second application step (72, 73, 74) with a water-additive mixture, wherein the additive is an adhesive and / or a wet strength agent, the fibrous web (305) is produced free from further consolidation.

8. Method according to one of the preceding claims, characterized in that the second application step d) (72, 73, 74) is carried out on the same side of the consolidated fiber fabric (305) as the first application step c) (71 ).

9. Method according to one of the preceding claims, characterized in that the second application step d) (72, 73, 74) is carried out on the opposite side of the consolidated fiber fabric (305), relative to the first application step c) (71).

10. Method according to one of the preceding claims, characterized in that a third application step f) (73) after the second application step e) (72) is carried out. 11 . Method according to one of the preceding claims, characterized in that the third application step f) (73) is carried out on the opposite side of the fiber fabric, relative to the second application step d) (72).

12. Method according to one of the preceding claims, characterized in that the consolidation step d) (8) of the fiber fabric (300) is carried out directly after the first application step c) (71), and in that in the consolidation step d) (8) a pressure of greater than 10 MPa, in particular greater than 20 MPa, preferably greater than 30 MPa, is exerted on the fiber fabric (300).

13. Method according to one of the preceding claims, characterized in that in the consolidation step d) (8) a structuring, preferably one which increases the strength, of the fiber fabric (300) is carried out simultaneously, such that a planarly consolidated fiber web (305) with high-pressure and low-pressure zones is formed.

14. Method according to one of the preceding claims, characterized in that a pre-consolidation step i) (6) is carried out before the first application step e) (71).

15. Method according to one of the preceding claims, characterized in that a distribution and control system, and at least one moisture measuring device (63) after a last application step, preferably arranged after each application step c), e) or f), and that a quantity of the applied fluid is distributed and regulated in each application step by the distribution and control system such that the supplied quantity of fluid, preferably water, is adjusted during operation of the machine.

16. Method according to one of the preceding claims, characterized in that in the application steps (7) the applied fluid is applied as a spray jet, drops, mist, steam, foam, curtain, and / or via a roller.

17. Method according to one of the preceding claims, characterized in that in the application steps (7) the fluid is applied to the fiber fabric from one side, and that on the opposite side the fiber fabric (300, 305) is vacuumed by a vacuum device (31) in such a way that the fluid applied on one side will penetrate deeper into the fiber fabric (300, 305).

18. Method according to one of the preceding claims, characterized in that at least one drying step g) (10) is carried out during the production of the fibrous web (309), and in that the at least one drying step g) (10) dries the consolidated fiber fabric (309) without contact by means of an electrically heated drying device (10); preferably, the drying device (10) is formed by infrared heating elements (10) or through-air drying hoods (10).

19. Machine (1) for producing a fibrous web (309), preferably a tissue, paper or cardboard web or a nonwoven web, in particular for carrying out the method according to one of the preceding claims, comprising a) a raw material processing plant (2) for the low-water processing of cellulose-containing fibers (200), preferably fresh fiber pulp in bale form (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), further comprising b) a dry-forming device (4) for forming the individual fibers and / or fiber bundles (209) in an air stream into a flat fiber web (300) on a preferably permeable forming belt (40); c) a first application device (71) for applying a fluid to the preferably flat fiber fabric (300), in particular for applying water;d) a consolidation device (8) for consolidating the flat fiber fabric (300) by applying pressure in a press nip; e) a second application device (72, 73, 74) for applying a fluid to the preferably flat, consolidated fiber fabric (305), in particular for applying a water-additive mixture; characterized in that the raw material processing plant (2) for low-water processing and the fiber web plant (3) for dry forming are operatively connected in such a way that the applied quantities of fluid are regulated via a distribution and control system (60) during operation of the machine to the parameters of the raw material processing plant (2) and the fiber web plant (3).

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