Method and machine for producing an air-laid fibrous web

Abstract

The invention relates to a method and a machine for producing an air-laid fibrous web from a fibrous material (200), in which the fibrous material (200) is processed with little water in order to form a fiberized fibrous material (209) and the fibrous web is formed from the fiberized fibrous material in an air-laying method. During preparation, the fibrous material (200) is conveyed by a first conveying device (241) using a first mass flow and is then further processed in at least one first fiberization device (222) and then in a final fiberization device (223) in stages in order to form fiberized fibrous material. The invention is characterized in that a first mass flow measuring device (101) is provided in the preparation process such that the first mass flow conveyed into the first fiberization device (222) is detected and in that the first conveying device (241) adapts the conveyed first mass flow on the basis of a detected first mass flow value.

Description

[0001] Method and machine for producing an air-soluble fiber web

[0002] The invention relates to a method for producing an air-laid fibrous web, in particular a dry-formed paper, cardboard or tissue web or a nonwoven web, from a fibrous material, in particular in the form of bales or sheets, wherein the fibrous material

[0003] - is processed in a fiber material preparation process to a fiberized fiber material with low water content, preferably waterless;

[0004] - in a low-water fiber web manufacturing process, an air-laid fiber web is formed from the fiberized fiber material, preferably with a continuous production speed of greater than or equal to 300 m / min;

[0005] during the processing process

[0006] a) the fiber material is conveyed by a first conveying device with a first mass flow; and

[0007] b) the conveyed fiber material is then processed stepwise into fiberized fiber material in at least a first fiberizing device and a final fiberizing device.

[0008] The invention also relates to a machine for producing an air-laid fibrous web, in particular a dry-formed paper, cardboard or tissue web or a nonwoven web, from a fibrous material, in particular in the form of bales or sheets, in particular for carrying out the method according to claim 1, comprising:

[0009] - a low-water fiber material processing plant; and

[0010] - a fiber web manufacturing plant;

[0011] the low-water fiber material processing plant further includes:

[0012] - at least a first conveying device; and

[0013] - at least a first and last fiberizing device;

[0014] the fiber web manufacturing plant further includes:

[0015] - at least one forming device; and - at least one solidification device; and

[0016] - a winding device; and

[0017] - preferably a final mass flow measuring device;

[0018] Furthermore, a higher-level control and regulation device is included, which can be connected to the first conveying device.

[0019] Many fibrous webs, and especially paper, cardboard, and tissue webs, were and still are produced almost exclusively using the wet process on an industrial scale. For this process, unless recycled paper is used, baled market pulp is typically dissolved in large quantities of water in a vat, resulting in a fiber suspension consisting of approximately 99% water and only about 1% fiber by weight. This fiber suspension is then applied to a forming wire via a headbox to form sheets. The resulting fibrous web is subsequently dewatered or dried by pressure and heat until it can be wound up or otherwise processed. The wet process has the advantage that hydrogen bonds form between the individual fibers during dewatering or drying, giving the fibrous web the necessary strength.However, a disadvantage of this process is that drying the fiber web requires large amounts of energy. Especially in light of current climate change, there is therefore an intensive search for alternatives to this traditional wet process.

[0020] As an alternative to the wet process, the dry air lay-up process, also known as the dry lay-up process, is already established. In this process, fibers are laid down to form a fiber web in a largely dry state. To give the fiber web the necessary strength, only relatively small amounts of water (for the formation of hydrogen bonds) and / or other binders are added. This results in significantly less energy being required for drying. One challenge with this process is achieving good and uniform fiber distribution (also called formation). Unlike in suspension, dry fibers tend to form undesirable clumps. Therefore, precise fiber separation is extremely important. For this reason, so-called "fluff pulp" or fluff cellulose is generally used for the dry air lay-up process.This refers to virgin fiber pulp that has been pretreated so that the individual fibers already have fewer and / or weaker bonds to each other. This makes the fluff pulp more voluminous, more absorbent, and better suited for the dry air layup process. However, fluff pulp, which is usually produced in rolls, is much more expensive than ordinary baled market pulp, as is typically used in the paper industry. Therefore, the dry air layup process is currently used primarily only for the production of sanitary products, such as diapers, and not for the production of paper, cardboard, or tissue webs, at least not on an industrial scale. For such an industrial scale, the use of fluff pulp would be uneconomical, despite currently high energy costs.

[0021] It would therefore be advantageous if a way could be found to produce a fibrous web, in particular a paper, cardboard or tissue web or nonwoven web, on an industrial scale, with sufficiently good formation using the dry air laying or dry forming process from the relatively inexpensive conventional baled market pulp.

[0022] The production of a fibrous web from baled pulp using the dry air-laying process is disclosed in publication WO 2023 / 280812 A1. A process and an apparatus for producing an air-laid product or a nonwoven fabric from a starting material, in particular from cellulose material in the form of a bundle, such as a bale of pulp, are disclosed, offering greater economic efficiency and more flexible application. For the fibrous web production plant, the raw material preparation plant with metering devices is intended to provide a continuous mass flow of fiberized material. The publication discloses various solutions and arrangements with material buffers and multiple comminution and fiberization systems to supply a constant mass flow to the fiberization systems and the subsequent fibrous web production plant.

[0023] However, tests with these configurations have shown that the result, especially the formation of the air-laid fiber web, is still not satisfactory even with this method.

[0024] This is particularly evident when production speeds are increased to an industrial, economic scale. The air-laid fiber web still exhibits unsatisfactory qualities, such as in terms of formation, feel (haptics), and appearance (optics). Furthermore, the basis weight profile in the machine (MD) and cross (CD) directions shows excessive variation.

[0025] The terms "dry-formed" can be understood equivalently as "dry-laid", "air-laid" or "dry-formed" and in English as "air-laid", "air-formed", "dry-laid" or "dry-formed".

[0026] The object of the invention is to provide a method and a device for the low-water or dry production of a high-quality air-laid fibrous web for a consistently high industrial production speed with low water usage while maintaining high quality properties of the fibrous web.

[0027] The fiber web should exhibit high mechanical strength, preferably tear strength or tensile strength in both dry and wet conditions, and quality factors such as good and uniform formation, a constant basis weight profile in the machine-side (MD) and cross-side (CD) directions, as well as quality parameters regarding appearance and feel. Furthermore, for example, in a preferably manufactured tissue web with low- and high-pressure zones, the feel, appearance, and absorption rates are also crucial. This is evident, for instance, in manufactured wipes for household use, where the customer expects high absorbency, a pleasing appearance, and a good feel.

[0028] According to the invention, a first mass flow measuring device is provided in the processing process, so that the first mass flow conveyed into the first fiberizing device is detected and that the first conveying device adjusts the conveyed first mass flow on the basis of the detected first mass flow value.

[0029] The inventors recognized that improved mass flow control could achieve optimal quality parameters and formation of the fiber web at industrial production speeds. This involves gradually transforming a discontinuous process into a continuous one.

[0030] The first conveying device is already directly connected to a final mass flow measuring device, but this had not yet achieved sufficiently good results; only an arrangement of a first mass flow measuring device immediately after the first conveying device and a control system based on the mass flow values ​​recorded from the first and last mass flow measuring devices could enable a quasi-continuous approximate process.

[0031] For industrial-scale production, a high, continuous production speed or fiber web speed of 300 m / min or greater, in particular 400 m / min or greater, preferably 500 m / min or greater, and most preferably 600 m / min or 800 m / min, is desired, along with a width of the continuously produced fiber web of 0.5 m or greater, preferably 1 m or greater, in particular 2.7 m or greater and less than 7.2 m, up to 10 m or less. The proposed process is particularly suitable for producing such fiber webs.

[0032] An air-laid fiber web can be, for example, a dry-formed paper, cardboard or tissue web or a nonwoven web, usually with a basis weight in the range of 5 g / m². 2 up to 600 g / m² 2In an alternative embodiment of the process, the produced fiber web is a dry-formed tissue web with low- and high-pressure zones. Particularly preferably, the dry-formed tissue web has a basis weight of 5 g / m². 2 up to 75 g / m² 2 , especially of 15 g / m² 2 up to 60 g / m² 2 , preferably of 25 g / m² 2 up to 45 g / m² 2 , particularly preferably 28 g / m² 2 up to 42 g / m² 2 The proposed method is particularly suitable for the production of such fibrous webs.

[0033] The required mass flows of fiber material per hour are more than 500 kg / h, in particular more than 1000 kg / h, preferably more than 1500 kg / h of frayed fiber material for fiber web production. The proposed process is particularly suitable for producing such large quantities of fiber web.

[0034] The dry-formed tissue web can be single-layered, or in particular, two-, three-, four-, or more-layered. For example, in a possible design with multiple dry-forming units, it is quite feasible to introduce different fiber materials to each unit. This could result, for instance, in a three-layer fiber web with a top, middle, and bottom layer when using three dry-forming units. Generally, when using the same fiber material in a design with multiple dry-forming units, a single-layer fiber web is assumed, even if it is formed by, for example, three dry-forming units.To distinguish between the manufactured fiber webs, for example a tissue, paper or cardboard web or a non-woven web, the following distinction is made, which is based on fiber length, density and fiber bonding type.

[0035] 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, predominantly bonded by hydrogen bonds (OH bonds) and with a bulk density of greater than or equal to 0.4 g / cm³, is placed beneath a tissue, paper or cardboard web. 3 understood.

[0036] The fibers used in a tissue, paper, or cardboard web are further characterized by a slenderness ratio (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. The proposed method is particularly suitable for the production of such fiber webs.

[0037] A nonwoven web, which also consists primarily of fibers, is defined, as a key distinction from tissue, paper, or cardboard webs, by having a fiber content of between 30% and 50% of very long fibers with an average fiber length of more than 5 mm, or continuous fibers, which determine the nonwoven characteristics. Furthermore, a fiber-to-diameter ratio of greater than or equal to 300 is targeted for a nonwoven web.

[0038] The remaining fiber content of a nonwoven fabric web can be composed differently, and the bulk density should be below 0.40 g / cm³. 3 to classify them as nonwovens.

[0039] Another distinguishing feature between a nonwoven web and a tissue paper or cardboard web lies in the way the fibers are bonded to each other. In nonwovens, the fibers are bonded by interlocking (through entanglement, for example, "spun-lacing" or "hydro-entangling") and / or by cohesion and / or adhesion. However, it is also common for nonwoven webs produced using the wet-forming process, which is similar to papermaking, to be referred to sometimes as nonwovens and other times as long-fiber specialty paper webs.

[0040] A structured and / or consolidated fiber web, preferably a tissue web with low- and high-pressure zones, is defined as a fiber web that maintains a constant basis weight distribution in the machine direction (MD) and the transverse direction (CD) after structuring. This differs from an embossing or structuring process known in tissue web production as "embossing," where the fibers are "bent" into the desired structure, and the previously formed fiber layup with its existing fiber bonds partially dissolves as the fibers pull apart within the layup, resulting in different basis weights. In the present structuring and / or consolidation process, the fiber layup is consolidated without any fiber elongation relative to each other.

[0041] A fibrous web with low and high pressure zones, preferably a tissue web with low and high pressure zones, is further characterized by the fact that the fibrous web is consolidated, compressed or pressed over its entire surface, meaning that low and high pressure zones are consolidated in different proportions to each other.

[0042] In an alternative embodiment, the method is characterized in that the fiber material, which is processed in stages, is conveyed by a second conveying device into the last fiberizing device with a second mass flow after leaving the first fiberizing device.

[0043] Advantageously, the second conveying device can achieve a continuous mass flow with maximum permissible fluctuations. Alternatively, the method can provide for a final mass flow measuring device during the fiber web manufacturing process, so that a final mass flow, preferably calculated from a measured basis weight, of the produced air-laid fiber web is measured, and the first conveying device adjusts the conveyed first mass flow based on the measured first mass flow value and the final mass flow value.

[0044] In particular, the final mass flow before or in a dry forming device can be measured, for example, by measuring devices in the supply lines and / or distribution channels of the dry forming device.

[0045] Preferably, the final mass flow rate can also be determined by measuring the basis weight of the fiber fabric or web using an online measuring device, which can, for example, measure the basis weight in the transverse direction (CD) and also in the machine direction (MD). This can then be used in combination with known variables or parameters such as the machine speed and the width in the transverse direction of the fiber fabric to calculate the final mass flow rate.

[0046] In an alternative embodiment, the method is characterized in that a second mass flow measuring device is provided after the second conveying device, in particular after the last fiberizing device, preferably directly on or after the second conveying device, so that an emerging second mass flow is detected and that the second conveying device adjusts the conveyed second mass flow on the basis of the detected second mass flow value.

[0047] In an alternative embodiment, the first conveying device may adjust the conveyed first mass flow based on the detected second mass flow value. In an alternative embodiment, the second conveying device may adjust the conveyed second mass flow based on the detected second mass flow value and the last mass flow value.

[0048] In an alternative embodiment, the method is characterized in that the second mass flow of fiber material is conveyed in such a way that the second mass flow and the last mass flow of the fiber material are essentially identical.

[0049] In an alternative embodiment, the method is characterized in that a fiber material stream recovered from the machine is added to the second mass stream, and that the second mass stream of fiber material is conveyed in such a way that the second mass stream and the last mass stream of fiber material are essentially identical.

[0050] In an alternative embodiment, the method is characterized by the fact that the progressively fiberized material is temporarily buffered in an intermediate buffer after leaving the first fiberizing device; in particular, the intermediate buffer is included in a second conveying device. Advantageously, the intermediate buffer allows for a certain degree of decoupling of the first and last fiberizing devices, as well as the first and second conveying devices, depending on the size of the intermediate buffer and the required mass flow rate. This makes it possible to maintain a constant mass flow rate in the fiber web production plant and simultaneously to set the respective optimal operating parameters for the fiberizing devices.

[0051] In an alternative embodiment, the method is characterized in that the intermediate buffer continuously thickens the progressively processed fiber material after it leaves the first fiberizing device in an air separator, preferably by means of gravity and / or a belt press.

[0052] In an alternative embodiment, the method is characterized in that the first mass flow rate is set within a first fluctuation range of + / - 10%, in particular + / - 7.5%, preferably + / - 5%, relative to the last mass flow rate, and / or the second mass flow rate is set within a second fluctuation range of + / - 2%, in particular + / - 1.5%, preferably + / - 1%, particularly preferably essentially the same, relative to the last mass flow rate.

[0053] According to the invention, the machine for producing an air-laid fibrous web is characterized in that a first mass flow measuring device is included upstream of the first fiberizing device and can be connected to the superior control and regulating device, so that an operative connection with the first conveying device is created.

[0054] Alternatively, the machine may be provided with a connection between the higher-level control and regulating device and at least one final mass flow measuring device, such that the first mass flow measuring device and the at least one final mass flow measuring device control and regulate the delivery rate of the first conveying device.

[0055] In an alternative embodiment, the machine is characterized by the inclusion of a second conveying device downstream of the first fiberizing device and upstream of the last fiberizing device, and a second mass flow measuring device, and by the fact that the second mass flow measuring device is connectable to that of the higher-level control device, thus establishing a functional connection with the second conveying device. In an alternative embodiment, the machine is further characterized by the fact that the second conveying device comprises a belt press and / or a rotating shredding roller.

[0056] In an alternative embodiment, the machine is characterized in that the first conveying device comprises a screw conveyor and / or a vibrating conveyor and / or a driven unwinding device.

[0057] In an alternative embodiment, the machine is characterized in that the first mass flow measuring device comprises an optical measuring system, preferably comprising an optical sensor and an evaluation device which uses artificial intelligence to detect the shape and size of the fiber material, preferably in the form of crushed chips.

[0058] In an alternative embodiment, the machine is characterized in that the first mass flow measuring device comprises a pressure measuring sensor, preferably arranged in or below a screw conveyor and / or a vibratory conveyor.

[0059] In an alternative embodiment, the machine is characterized in that the second mass flow measuring device is an optical measuring system, preferably a measuring system based on light scattering, or a measuring system based on microwaves or a measuring system based on a dielectric resistance.

[0060] In an alternative embodiment, the machine is characterized in that the at least one consolidation device can consolidate and / or heat and / or structure the fiber layup.

[0061] In an alternative embodiment, it may also be provided that two, three or four consolidation devices are arranged, which successively consolidate and / or structure and / or heat the fiber fabric or the fiber web.

[0062] Furthermore, it may be provided that, in the case of multiple stabilization devices, for example a pre-stabilization device, a first stabilization device and / or a final stabilization device are provided, and that the pressures or line loads applied for stabilization of the fiber layup by the pre-stabilization device are lower than the line loads in the first stabilization device. Furthermore, the line load in the first stabilization device may be less than or equal to the line load in a final stabilization device.

[0063] The individual consolidation gaps, or press gaps or press nips, can each be formed by at least two press rollers or combined in a multiple press roller arrangement, whereby one, two, or three consolidation gaps can be formed in combination with the same press rollers. The consolidation devices can also include additional support elements, such as a forming belt or a consolidation belt, which can be guided through the consolidation gap or press gap.

[0064] The invention expressly extends to embodiments which are not given by combinations of features from explicit cross-references of the claims, whereby the disclosed features of the invention can be combined arbitrarily with one another - insofar as this is technically sensible.

[0065] Further features and advantages of the invention will become apparent from the following description of a preferred embodiment with reference to the drawing.

[0066] The invention will now be explained with reference to the following figures. Fig. 1 shows a schematic representation of a simplified fiber material processing plant 2 for the low-water processing of fiber material 200;

[0067] Fig. 2 shows a schematic representation of a fiber web manufacturing plant 3 for the production of a dry-formed fiber web 309;

[0068] Fig. 3 shows a schematic flowchart representation of the process steps.

[0069] To clarify the individual directions, a higher-level Cartesian coordinate system is used in the figures, which allows the individual directions to be illustrated. The x-direction represents the longitudinal extent, also known as the machine direction (MD). The y-direction corresponds to the direction perpendicular to the machine direction and is called the cross-direction (CD), while the z-direction corresponds to the vertical direction.

[0070] Possibly, further transport and / or movement directions of other features are indicated with separate arrows.

[0071] Figures 1 and 2 show a possible embodiment of a machine 1 or a manufacturing process, particularly on an industrial scale, for producing an air-laid fibrous web 309, in particular a dry-formed paper, cardboard or tissue web or a nonwoven web, in particular a tissue web with low- and high-pressure zones, most preferably a tissue web with a basis weight of 5 g / m². 2 up to 75 g / m² 2 , in schematic representation.

[0072] The fiber web production plant 3 for producing a continuous fiber web 309 is designed for a high, continuous production speed of 300 m / min or greater, in particular 400 m / min or greater, and preferably 500 m / min or greater. The width of the continuously produced fiber web 309 can be greater than or equal to 0.5 m to less than or equal to 10 m, according to the operator's requirements. For example, in tissue machines, it is convenient to design them as "single width" or "double width," as is common in the market, which typically corresponds to a width of approximately 2.7 m to 3.6 m for a "single width" version.

[0073] The typical basis weights of the continuously produced fiber web 309 are in the range of greater than or equal to 5 g / m². 2 up to and including 600 g / m² 2 , preferably with a tissue web of 5 g / m² or greater 2up to and including 75 g / m² 2 , particularly preferred with a tissue web of 28 g / m² 2 up to 42 g / m² 2 .

[0074] This results in very high mass flows of required fiber material per hour, whereby a fiber material preparation plant 2 should be designed in such a way as to provide more than 500 kg / h, in particular more than 1000 kg / h, preferably more than 1500 kg / h of fiberized fiber material 209.

[0075] These boundary conditions have a direct influence on the required quantities, storage volumes, transport capacities, and transport routes of the fiber material. Therefore, it is crucial to consider the fiber material preparation plant 2 and the fiber web production plant 3, which are directly interconnected, as a single machine 1.

[0076] Figure 1 schematically depicts a possible embodiment of a low-water processing plant or a low-water fiber material processing plant 2, in which the fiberized material 209, preferably individual fibers and / or fiber bundles essentially free of knots, for example from fiber material 200, in particular market pulp and / or fiber-containing recycled material as bales 200, is produced stepwise by at least one shredding device 221 and at least two shredding devices 222, 223 connected in series or successively. During fiber material processing and further transport, the fiber material or shredded or fiberized fiber material always forms a fiber-air mixture with varying concentrations of fibers dissolved in air.

[0077] The fiber material preparation plant 2 or the fiber material preparation process, especially at production speeds of more than 300 m / min or at a mass flow of required fiber material of more than 500 kg / h, includes at least the following essential features:

[0078] • at least one shredding device 221 ,

[0079] • at least one, preferably two, fiberizing device(s) 222, 223, • at least one fiber / airflow transport system.

[0080] Fiber processing plant 2 is suitable for processing a fiberized fiber material from a starting material, in particular fiber material, preferably marketed pulp and / or recycled fiber material in the form of a bale, with low water content, preferably waterless, especially at production speeds of more than 300 m / min or at a mass flow rate of required fiber material of more than 500 kg / h. The fiber processing process in fiber processing plant 2 comprises at least the following essential processes or process steps:

[0081] • at least one comminution process,

[0082] • at least one, preferably two, fiberizing process(s),

[0083] • at least one fiber / airflow transport process.

[0084] When the shredded or fiberized material is transported through a processing device or from one processing device to the next, it is referred to as a fiber / airflow. Before and / or after shredding or fiberization, a further airflow or fiber / airflow 91, 92 can be supplied to the fiber material or a fiber / airflow, and the fiber / airflow is fed via one or more distribution channels to a fiber web production plant 3, shown in Fig. 2, for the production of a dry-formed fiber web 309. The fiber / airflow exhibits both a volumetric and a mass flow rate.

[0085] It is also conceivable to have several fiber material preparation plants 2 arranged in parallel, which can supply a single fiber web production plant 3 (Fig. 2). This is advantageous if a single fiber material preparation plant 2 cannot produce the required quantity of fiberized fiber material and / or if different types or grades of starting material 200 or fiber material 200 are used. This can be advantageous, for example, for a multi-layered, in particular two-, three- or four-layer, fiber web 309, or if, for ecological or economic reasons, the addition of a proportion of recycled material to the fiber web 309 is desired.

[0086] In this case, a fiber web production plant 3 can preferably be configured with several, in particular two, three, or four, dry forming devices, with each individual dry forming device ideally having its own fiber material preparation plant. The corresponding number of dry forming devices can be arranged upstream of the dry forming device 4C shown in Fig. 2. Preferably, all dry forming devices deposit the fiberized fiber material onto a common forming screen 41, with the subsequent dry forming device then depositing it onto the fiber layup previously deposited on the forming screen. The basic remaining structure of the fiber web production plant and fiber material preparation plant can be configured as shown, but it can also optionally be adapted to the processed fiber material in details such as the operating parameters.

[0087] The low-water, and especially waterless, fiber material preparation makes a crucial contribution to the quality and properties of the produced dry-formed fiber web 309, as well as to the overall balance of the manufacturing process with regard to economic and energy aspects.

[0088] A major challenge for industrial-scale production is the use of baled material 200 as the starting material or fiber material. This requires transforming a discontinuous process into a continuous one, with the very high production volumes of several thousand tons of finished fiber web 309 per year posing a particular challenge. For efficient and economically viable operation of the fiber web production plant 3, a production speed of more than 300 m / min, in particular more than 400 m / min, and preferably more than 500 m / min, is targeted.This is at least more than two to six times higher compared to conventional fiber web manufacturing plants for producing a dry-formed fiber web, and presents all previously known fiber material preparation and fiber web manufacturing with new challenges in maintaining a reliable and high-quality production process under these conditions.

[0089] These high, industrial-scale production volumes mean that the available fiber material 200 should ideally be stored as compactly as possible to minimize warehousing. An important aspect of low-water fiber material preparation is that the required volume of the processed fiber material 200 increases steadily until the final processing of the fiberized material in the fiber web plant 3. The increase in volume can range from the delivered starting material or fiber material, particularly market pulp 200 in bales, to the fiberized material dissolved in the fiber / airflow, comprising individual fibers and / or fiber bundles, before the fiber web production plant 3, or immediately before or in the dry forming unit 4C, typically by a factor of 30,000 to 50,000. This necessitates minimal warehousing.The intermediate buffering of fiberized fiber material in the fiber material processing process should be kept as low as possible and only provided at crucial processing steps.

[0090] Another aspect for the overall balance is to keep the supplied fiber material high in terms of its availability and low in terms of its cost.

[0091] In current drying and dry forming processes, fluff pulp, or "fluff cellulose," is typically used in roll form for finished products. The fluff pulp can be fed directly and continuously to a single fiberizing unit, thus ensuring a consistent mass flow with minimal fluctuations to the fiber web production system.

[0092] In contrast, current wet layup processes typically use an industry-standardized market-grade virgin pulp, usually in bale form. This type of pulp also dominates the current global market share of virgin pulp compared to fluff pulp. Both types could originate from the same virgin pulp production plant; however, the market-grade pulp is produced using significantly less complex processes and is therefore available in larger quantities and at lower costs.

[0093] A key distinguishing feature of fluff pulp, compared to standard market pulp, is that at least two additional manufacturing steps are performed. These result in a lower material density due to a higher air content and / or a significantly lower variation or tolerance range in the basis weight of the final, rolled fluff pulp compared to standard market pulp. Typically, with fluff pulp in roll form, a large portion of the fiber preparation for the resulting fiber web is already integrated into the fluff pulp manufacturing process. Fluff pulp production is more complex and labor-intensive. Furthermore, the composition of the fluff pulp can be precisely tailored to the final fiber web by adding additives during its production. The most important requirement for fluff pulp is a low tolerance in mass distribution.of the basis weight compared to market pulp. This is necessary for known fiber web manufacturing processes to provide a continuous mass flow.

[0094] Fluff pulp typically already contains additives such as "debonding agents" that facilitate the fusing of the fiber material or the separation of individual fibers from one another and counteract agglomeration of the individual fibers in the further manufacturing process. This is usually not the case in commercially available pulp or is reduced to a minimum, as the aim here is to achieve the lowest possible production costs.

[0095] The term fluff pulp, "fluff pulp," or fluffy pulp must therefore be clearly distinguished from market-grade virgin fiber pulp or market-grade pulp. Virgin fiber pulp can be understood as a general term encompassing both types / grades.

[0096] Furthermore, market pulp in bale form, compared to fluff pulp in roll form, is characterized by a smaller storage volume and better transportability, as well as a higher density or concentration of fibers per cubic meter of volume. This is due, on the one hand, to the form of delivery, for example, a cubic bale versus a cylindrical roll, and on the other hand, to the lower material density of the fluff pulp itself. A bale of market pulp can consist of numerous stacked sheets of pulp. This market pulp can be NBSK pulp, as is commonly used for the wet process production of paper, board, or tissue. Market pulp can have a material density between 800 kg / m³. 3 and 1,000 kg / m² 3 , in particular of around 920 kg / m² 3, exhibiting, wherein the individual cellulose sheets can have a thickness between 1.0 mm and 2.0 mm, in particular of approximately 1.5 mm.

[0097] Alternatively, a bale can also consist of recycled material, for example, pressed recycled material. In this case, the bale as a whole is coarsely pre-shredded by at least one shredding device or with an optional upstream further shredding device, so that the pre-shredded recycled material essentially corresponds to the quantity of cellulose boards supplied.

[0098] The general term starting material or fiber material is used for pulp-containing fiber material, in particular market pulp and / or recycled fibers.

[0099] A particularly efficient recycling method is the direct reuse of so-called "machine scrap" originating from the machine itself, especially the fiber material preparation plant and / or the fiber web production plant. This high-quality machine scrap can be directly returned to machine 1, for example, fiber material preparation plant 2 and / or fiber web production plant 3. Alternatively, in the case of contamination, for example by additives, the machine scrap can be reprocessed before being reintroduced into the machine. This allows for a further improvement in the overall efficiency of the manufacturing process. An efficient design of this recycling process can also constitute a separate invention.A key feature for the industrial-scale production of a high-quality fiber web 309 is the integrated coupling and coordination of the two manufacturing processes: the low-water fiber material preparation plant 2 and the fiber web production plant 3. Both plants are equipped with a central control and regulation device 60, which enables them to operate in a coordinated, controllable, and regulating manner.

[0100] The low-water fiber material preparation process or fiber material preparation plant 2 is characterized by a stepwise comminution or fiberization 221, 222, 223 of the discontinuously supplied starting material 200, wherein at the end of the low-water fiber material preparation process a continuous final fiber / air stream 209, preferably comprising individual fibers and / or fiber bundles dissolved in air with a low proportion of knots or free of knots, is continuously provided with a maximum fluctuation or tolerance range in the range of + / - 4%, in particular + / - 2%, preferably less than + / - 1.5% of the mass flow required in the fiber web production plant 3.

[0101] The fiber material processing plant 2 comprises at least two comminution or fiberizing devices, with at least one final fiberizing device 223 being provided.

[0102] The discontinuously supplied starting material 200 is typically fed to a first shredding device 221 in the form of substantially cubic or cuboid bales 200, in particular pulp, preferably marketed pulp, comprising a plurality of stacked sheets or recycled material, via conveying means. As shown, for example, in Fig. 1, at least one bale 200 can be fed to the at least one first shredding device 221; in particular, several bales, especially three bales shown, are fed in a horizontal or vertical arrangement. Advantageously, an approximately uniform feeding of the bales has a positive effect on the shredding quality and the service life of the shredding device 221.

[0103] The first shredding device 221 is designed in such a way that it can perform a first shredding of the bales 200 into coarse pieces, chips or so-called chips 201.

[0104] In an alternative embodiment, for example, the shredding device 221 is designed as a shredder 221, in which the shredder 221 comprises at least one rotor which is provided with projections and has a diameter of about 300 to 450 mm and which is operated at a substantially constant speed of between 500 and 800 revolutions per minute.

[0105] The chips 201 can be stored in a storage unit 240, preferably a bulk container 240 or a silo 240. This is a larger storage unit 240, located in a fiber material processing line or the fiber material processing plant 2.

[0106] A "larger" storage unit 240 is understood to mean that, due to their construction or design, smaller intermediate storage units may be provided or arise in individual components of the fiber material preparation plant 2, but these are not suitable for continuously supplying the fiber web production plant 3 for several hours. The larger storage unit 240 enables the downstream plant to be supplied for a certain period of time without the need for a further supply of chips 201.

[0107] Advantageously, the storage unit 240 will be arranged after the comminution device of the chips 201, whereby the volume increase of the fiber material can be kept as small as possible, and a maximum storage capacity of the storage unit 240 of greater than or equal to 30 min, in particular greater than or equal to 60 min, preferably greater than or equal to 90 min, and less than or equal to 120 min of the production of the fiber web manufacturing plant 3 can be provided.

[0108] The size of the storage unit 240 can therefore be configured depending on the basis weight and width of the fiber web 309 and the production speeds of the fiber web production plant 3. The design of the storage unit 240 is geometrically optimized, enabling compact, low-air, volume-optimized storage of the chips 201.

[0109] Figure 1 shows a single stepwise fiberizing line downstream of the storage unit 240, comprising a conveying device 241 and two successive fiberizing devices 222, 223. Alternatively, a single storage unit 240 can also be provided to feed several, preferably two, three, or four, parallel fiberizing lines. It is understood that in such an embodiment, the conveying device 241 and the two successive fiberizing devices 222, 223 will be present in the same number as there are fiberizing lines.

[0110] Furthermore, at least one, preferably two or three or four, conveying device(s) 241 can be provided in the memory 240, which can enable a continuous discharge of the stored chips 201.

[0111] To assist in the discharge of the stored chips 201 from the storage unit 240, an airflow can be introduced directly at the outlet of the storage unit 240 or after the conveying device 241 via an air supply device 91, so that the chips 201 can distribute and mix in a subsequent distribution channel or fiber / airflow transport system in a first fiber / airflow and thus be transported to at least one comminution device 222, 223. According to the invention, at least one mass flow measuring device 101 is provided after the first conveying device 241, which can detect the conveyed first mass flow and perform a calculation with a last detected mass flow by a mass flow measuring device 100 included in the fiber web production plant 3, and controls and regulates the first conveying device in the conveyed mass flow via the higher-level control device 60.

[0112] A first fiberizing device 222 is arranged upstream of the last fiberizing device 223. As shown, the chips 201 are transported or conveyed to the first fiberizing device 222 by at least one conveying device 241 via a fiber / airflow transport system in a specific mass and volume flow.

[0113] The first and last fiberizing devices 222 and 223 each comprise at least one rotating rotor with cutting elements arranged around the rotor circumference, which fiberize a supplied fibrous material. Each fiberizing device also includes at least one filter device, preferably a sieve, which retains the fiber material fiberized by the rotor within the respective fiberizing device for a period of time, allowing the rotor with the cutting elements to further fiberize the material until the fiberized material can pass through the plurality of individual openings in the filter device and exit the fiberizing device. The residence time of the fiber material in the fiberizing device is measured from its entry into the device until its exit through the respective filter device.

[0114] The rotational speed and diameter of the rotor determine the speeds at which the cutting elements can move and strike the fiber material. The first and last fiberizing device 222, 223 can, for example, be designed as a hammer mill, with the cutting elements in this embodiment being hammers.

[0115] A first fiber / airflow, in particular comprehensively cleaned or stored chips 201, is fed to the first fiberizing device 222.

[0116] The supplied fiber material contained in the first fiber / air stream can be fiberized by the first fiberizing device 222 until a first fiberized fiber material, comprising individual fibers and / or fiber bundles with isolated nodes, is formed.

[0117] The first fiberized material can now pass through the filter device and then exit the first fiberizing device 222 as a second fiber / airflow. The volume and mass flow of the second fiber / airflow essentially corresponds to the volume flow of the first fiber / airflow.

[0118] The term "one volume flow essentially corresponds to another volume flow" means that minor deviations in both positive and negative directions are conceivable due to possible leaks and leakage, for example through bearings and fastenings, which allow a small amount of air to enter and / or escape compared to the rest of the contained air.

[0119] The term "one mass flow essentially corresponds to another mass flow or is constant" means that minor deviations in the negative direction are conceivable due to possible leaks and leakage, for example, through bearings and fastenings, which could allow a small amount of mass, especially fiber material, to be lost in the flow. The second fiber / air flow is fed to a second conveying device 251, and the second conveying device 251 feeds the material in a controlled and regulated manner to the final fiberizing device 223.

[0120] Optionally, an air supply 92 can be provided upstream of the second fiberizing device 223, which can increase and support the volume and mass flow from the second conveying device 251. This can advantageously compensate for any losses that may have occurred in the preceding fiber material preparation steps and also achieve improved fiberization in the final fiberizing device 223.

[0121] The second fiber / air stream can be temporarily buffered in an intermediate buffer 250 before the second conveying device 251. Alternatively, the intermediate buffer 250 can be incorporated into the second conveying device 251. The intermediate buffer thickens the fibers in the second fiber / air stream, for example, by means of a cyclone separator and / or a belt press, by separating the contained air. Preferably, the separated air is routed as a bypass around the intermediate buffer 250 and fed back into the fiber / air stream after the second conveying device 251.

[0122] In the embodiment with an intermediate buffer 250, the first fiberized fiber material can be formed into a compacted fiber intermediate web using a belt press.

[0123] When a fiber interlayer is formed, the enclosed individual fibers and / or fiber bundles with isolated nodes of the second fiber / airflow are separated from most of the air and slightly compacted, resulting in an interlayer with a constant thickness and mass. The thickness of the fiber interlayer should be between 1 cm and 25 cm, particularly between 2 cm and 15 cm, and preferably between 4 cm and 10 cm, to achieve sufficient but not excessive compaction without forming additional fiber bundles with nodes.

[0124] The fiber intermediate web can be regulated and controlled in terms of its production speed and / or its degree of compaction by the conveying device 251.

[0125] For constant mass flow control, the second conveying device 251, comprising a belt press with a variable feed rate, can convey the fiber intermediate web directly into the final fiberizing device 223.

[0126] Alternatively, a further comminution device, preferably a rotating, adjustable shredding roller, can be included in the second conveying device 251, which is suitable for pre-shredding the fiber intermediate web into uniform pieces. This further comminution device can be seen as a further means of achieving control of a constant mass or volume flow for the subsequent fiber web production plant 3. The pre-shredded pieces are fed to the final fiberizing device 223.

[0127] Advantageously, this can achieve a further reduction in the fluctuation range in the mass flow.

[0128] The second conveying device 251 is controlled and regulated by the higher-level control and regulation system 60.

[0129] Most of the previously separated air from the second fiber / airflow can be largely routed as a bypass around the second conveying device 251 and fed back into the second conveying device 251 immediately after or even before, thus supplying a fiber / airflow to the last fiberizing device 223.

[0130] The final fiberization device 223 fiberizes the first fiberized material of the supplied fiber / airflow, comprising individual fibers and / or fiber bundles with isolated nodes, until only individual fibers and / or fiber bundles essentially free of nodes or with a lower proportion of nodes than in the first fiberization device 222 remain. These fibers can then pass through a filter device, in particular a sieve or screen, included in the final fiberization device 223 as the last fiberized material. The last fiberized material 209 exits the final fiber / airflow device 223 as the last fiber / airflow.

[0131] Alternatively, a second mass flow measuring device 102 is provided downstream of the last fiberizing device 223, which can detect a second mass flow. Advantageously, the second mass flow measuring device 102 is arranged downstream of the intermediate buffer or the creation of the intermediate web, thus enabling precise control and regulation by the higher-level control and regulation device 60 with a smaller fluctuation range, and increasing the first volume flow of the last fiber / air flow 208.

[0132] Alternatively, a second mass flow measuring device 102' can also be provided after the last fiberizing device 223, particularly in the case of a direct feed of the intermediate web into the last fiberizing device 223.

[0133] After the low-water processing in the fiber material processing plant 2, the last fiberized fiber material is fed in a second volume stream 209 to the fiber web production plant 3 and thus leaves the fiber material processing plant 2.

[0134] The fiber web production plant 3 shown in Fig. 2 is described below. The fiber web production plant 3, or the fiber web production process, particularly at production speeds exceeding 300 m / min, comprises at least the following essential features:

[0135] • at least one 4C dry forming device,

[0136] • at least one, preferably two, solidification device(s) 81, 83, • at least one application device for a fluid 71, 72, 73,

[0137] • at least one drying device 110 or heating device 110 and one winding device 120.

[0138] The fiber web production plant 3 is suitable for producing an air-laid fiber web, especially at production speeds of more than 300 m / min. The fiber web production process in the fiber web production plant 3 comprises at least the following essential processes or process steps:

[0139] • at least one dry forming process 4,

[0140] • at least one, preferably two, solidification process(s) 8,

[0141] • at least one application process of a fluid 7,

[0142] • at least one drying process 11 and

[0143] • a roll-up process 12.

[0144] The fiber web production plant 3 comprises a dry forming process 4 with at least one dry forming device 4C, preferably two or three or four dry forming devices, which can be supplied with fiberized fiber material from a fiber material preparation plant 2 by one, preferably on both sides, supplied fiber / air stream 209.

[0145] The at least one dry forming device 4C forms a planar, continuous fiber fabric 300 onto a rotating support element, preferably a permeable forming belt 40 or a forming screen 40, wherein the fiber material is largely taken from the supplied fiber / air stream 209. The forming belt 40 runs in the direction of travel 22 indicated by an arrow.

[0146] The last fiber / airflow 209 exiting the fiber material preparation plant 2, or the fiberized fiber material 209, or the individual fibers and / or fiber bundles transported with the fiber / airflow, essentially free of knots 209, are fed directly into the at least one dry forming device 4C of the subsequent fiber web production plant 3 and distributed evenly transversely to the machine running direction MD of the fiber web production plant 3 via further means included in the at least one dry forming device 4C.

[0147] The resulting planar fiber fabric 300, made from shredded fiber material, is then consolidated at least once, preferably twice or three times, to form a consolidated fiber fabric 305. The consolidation 8 of the fiber fabric 300 takes place in stages during two or more consolidation processes. The at least one consolidation process 8 is carried out in at least one, preferably first, consolidation device 81.

[0148] Following the dry forming device 4C, at least one application process 7 is provided by means of at least one, preferably first, application device 71, which applies a fluid, preferably water and / or a water-additive mixture, to the fiber fabric 300 and / or to the solidified fiber fabric 305. Preferably, the first application device 71 is arranged upstream of the at least one solidification device 81 and applies a fluid to the fiber fabric 300.

[0149] After the at least one application device 71, the fiber web is dried or heated. This drying 11 is carried out by a drying device 110, preferably a contactless and / or electric drying device 110. The drying 11 is carried out below 350°C, in particular less than or equal to 250°C, preferably less than or equal to 100°C.

[0150] When specifying temperatures for drying and / or heating, these temperatures refer to the temperature of the heating elements used. The temperature acting on the fiber web or the fiber fabric, or the temperature reached, may be lower and depends on the production speed and the dimensions of the drying or heating equipment used. If the fiber fabric temperature is referenced, this will be explicitly stated. At the end of the manufacturing process, the produced fiber web 309 is wound up by a winding device 120 in a winding process 12.

[0151] Alternatively, at least one of the consolidation devices 81, 83 can be equipped with a strength-enhancing structuring device, which makes it possible to introduce an advantageously enhanced strength-enhancing structuring into the fiber web 305. Advantageously, this allows for increased strength of the fiber web compared to consolidation alone. Additionally, an aesthetically pleasing pattern can be introduced into the fiber web by means of the structuring.

[0152] If structuring is carried out in a consolidation step 8, for example, in the case of simultaneous consolidation and structuring in the at least one consolidation device, the press roller 811 can be designed as a structured press roller 811 with a surface structure and / or the press element 812 as a structured press element 812.

[0153] In the illustrated case with a first main consolidation device 81, which is arranged in a consolidation belt 41, the press roller 811 and the press element 812 can preferably have a smooth surface, and the consolidation belt 41 can have a surface structure that introduces a structuring into the fiber fabric 300. The consolidation belt 41 runs in the direction of travel 22 indicated by an arrow.

[0154] Following the dry forming process 4, a pre-consolidation process can be provided, which pre-consolidates the fiber layup 300 with a pre-consolidation device 83 before it undergoes main consolidation in the at least one consolidation device 81. Furthermore, a second (main) consolidation process can be carried out with a second consolidation device downstream of the at least one first consolidation device 81. The second consolidation device can advantageously form a consolidation gap consisting of a press roller and a press element, free from a further support element such as a consolidation belt.

[0155] Furthermore, the second consolidation device can also be designed as a structuring device, in which case the press roller will advantageously be designed as a structured press roller with a surface structure and / or the press element as a structured press element.

[0156] The individual fibers and / or fiber bundles contained in the last fiber / airflow, essentially free of knots, are laid down in the dry forming device 4C, preferably partly by the force of gravity, onto a rotating, permeable forming belt 40 and form a planar fiber fabric 300.

[0157] The dry forming process 4 in the at least one dry forming device 4C can be controlled and regulated by at least one included control and regulating means.

[0158] Furthermore, a mass flow measuring device 100 is arranged upstream of the winding unit 12, which enables relevant parameters of the produced fiber web, such as thickness, distribution, and formation, to be recorded. Preferably, a mass flow measuring device 100 extending in the transverse direction CD can be provided, which records the mass distribution or basis weight distribution of the formed fiber web. These parameters are used directly via the higher-level control device 60 as control variables in the first conveying device 241, and in particular the second conveying device 251, for conveying the fiber material being processed in the fiber material preparation plant 2, and are coordinated with each other.Furthermore, machine rejects from the fiber web production plant 3, such as the edge trimming described above or uncollected individual fibers and / or fiber bundles filtered from the ambient air, can preferably be recycled or recovered and, for example, reintroduced into the fiber material preparation plant 2 at a suitable point or fed directly to and / or into the dry forming device 4C. This is particularly advantageous if the machine rejects do not yet contain any additives and are essentially of the same quality as the fiberized material.

[0159] Machine rejects are defined as the formation of either clean or contaminated fiber material (contaminated by chemicals or additives) during the manufacturing process of the fiber web 309. Ideally, both types of machine rejects can be directly processed via a recycling system and reintroduced into the manufacturing process. An improved recycling system can also constitute a separate invention.

[0160] In an embodiment with a first application device 71, it is advantageous if the first application device 71 is arranged upstream of the at least one solidification process 8 or the first solidification device 81. Furthermore, three application processes 7 can be provided downstream of the dry forming device 4C. As shown in Fig. 2, a first application device 71, a second application device 72, and a third application device 73 can be provided. The first application device 71 can be arranged upstream of the at least one solidification process 8 or the at least one, preferably first, solidification device 81.

[0161] The second application device 72 and the third application device 73 can be arranged after the at least one consolidation process 8 or the at least one, preferably first, consolidation device 81. Furthermore, at least one consolidation device 81, 83 is provided after the dry forming device 4C, which consolidates and preferably structures the fiber fabric 300. In an alternative embodiment, it can also be provided that two, three, or four consolidation devices are arranged, which successively consolidate and / or structure and / or heat the fiber fabric or the fiber web. The individual consolidation slits or press nips can each be formed by at least two press rollers or combined in a multiple press roller arrangement.The consolidation devices can also include a support element, for example a forming band 41 or a consolidation band 42, which can be guided through the consolidation gap or press gap.

[0162] 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.

[0163] Alternatively, the application devices can also be designed such that the fluid is applied in the form of droplets, foam, mist, or vapor. Alternatively, a curtain applicator or a roller applicator can also be provided, wherein the roller applicator can advantageously be integrated into a consolidation device 81 and coated with a fluid via an application means, for example, the press roller, which then transfers the fluid to the fiber fabric 300 in the subsequent press gap.

[0164] Furthermore, in an alternative embodiment, a pre-solidification device 83 can be arranged after the dry forming device 4C and before the first application device 71.

[0165] As shown in Fig. 2, the fibrous web can be transported through the drying device 110 with a support element, preferably a drying belt 42 or a drying screen 42, or unsupported, i.e., without a support element. The drying belt 42 shown runs in the direction 22 indicated by an arrow.

[0166] Furthermore, the non-contact drying device 110 can, for example, be designed as a hot air drying device, a flow-through drying hood, a TAD drying device, or an infrared drying device. Preferably, all embodiments can be equipped with electric heating of the drying device 110.

[0167] Advantageously, by means of contactless drying 11 the properties of the fiber web 309 with regard to its thickness, its feel properties and its absorption capacity can be precisely adjusted and maintained.

[0168] Due to the low overall moisture content in the described drying process, the length of the drying device 110 in the machine direction MD can be kept very compact compared to the usual drying sections from wet forming processes, thus advantageously significantly reducing the overall length of the fiber web production plant 3 and infrastructure costs. Compared to conventional dry forming processes, the further reduced total amount of moisture-increasing fluids used, especially water and water-additive mixtures, also results in a significant reduction in the required drying energy.

[0169] Another important component of decarbonization is not only the reduction of the total energy used, but also the replacement of conventional fossil fuel-heated equipment with efficient electric heating. This enables the use of renewably generated electricity and thus represents an important step towards a CO2-neutral fiber web 309.

[0170] The first application device 71 can be arranged directly upstream of the at least one, preferably first, solidification device 81 and apply a fluid. Furthermore, the first application device 71 can apply water, either ordinary or distilled. Ordinary and distilled water means that it is free of anhydrous artificial or chemical additives.

[0171] Alternatively, the first application device 71 can be configured to apply 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 of the produced fiber web 309 in its dry state. Dry-strength agents are also suitable for application before consolidation 8 because they exhibit a lower tendency to stick than adhesives or wet-strength agents.

[0172] Furthermore, as shown in Fig. 2, a first, second and third application device 71, 72, 73 can be provided. For uniform application, it can be advantageous if at least one of the three application devices is arranged on opposite sides of the fiber layup; preferably, the second and third application devices are arranged on opposite sides of the fiber layup.

[0173] Furthermore, the second and third application devices 72, 73 can apply water or a water-additive mixture to the fiber fabric. Preferably, the second and third application devices 72, 73 are arranged downstream of the last consolidation device and apply a water-additive mixture, wherein the water-additive mixture comprises an additive from the group of adhesives or wet-strength agents.

[0174] Figure 3 shows the process described in Figures 1 and 2, with its process steps or processes, as a schematic flow diagram. The first mass flow measuring device 101 is shown directly after the first conveying by the first conveying device 241, and the second mass flow measuring device 102 is shown after the second conveying by the second conveying device 251 and after the last fiberizing by the last fiberizing device 223. Figure 3 also shows the assembled first mass flow control loop and the second mass flow control loop, and their connection to the higher-level control device 60, which also acquires the measured values ​​of the last mass flow measuring device 100, preferably located in the fiber web production plant before the winding unit 12.

[0175] List of reference signs

[0176] 1 machine

[0177] 2 Fiber material processing plant

[0178] 3 Fiber web production plant

[0179] 4 Dry forming process

[0180] 4C Dry Forming Device

[0181] 7 Application process

[0182] 8 Solidification process

[0183] 10 T drying process

[0184] 12. Roll-up process

[0185] 22 Direction of travel of the support elements

[0186] 40 Forming band

[0187] 41 Consolidation band

[0188] 42 drying belt

[0189] 60 Control and regulating device

[0190] 100 Mass flow measuring device

[0191] 71 first application device

[0192] 72 second application device

[0193] 73 third application device

[0194] 81 first solidification device

[0195] 83 Pre-solidification device 91 Air supply device

[0196] 92 second air supply device

[0197] 100 last mass flow measuring device

[0198] 101 first mass flow measurement system

[0199] 102 Second mass flow measuring system, position after 251 102' Second mass flow measuring system, alternative position after 223 110 T drying device

[0200] 120 winding device

[0201] 200 starting fiber material in the form of bales

[0202] 201. Shredded fibrous material or "chips"

[0203] 209 frayed fiber material as the last fiber / airflow

[0204] 221 first shredding device

[0205] 222 first fiberizing device

[0206] 223 last fiberizing device

[0207] 240 storage

[0208] 241 Conveyor device

[0209] 250 fiber processing device

[0210] 251 second conveying device

[0211] 300 fiber fabrics

[0212] 305 reinforced fiber fabric

[0213] 309 Fibre web

[0214] MD Machine direction of travel

[0215] CD machine transverse direction

[0216] z Vertical direction

Claims

1. Method for producing an air-laid fibrous web (309), in particular a dry-formed paper, board or tissue web or a nonwoven web, from a fibrous material (200), in particular in the form of bales or sheets, wherein the fibrous material (200) - is processed in a fiber material preparation process to a fiberized fiber material (209) with low water content, preferably waterless; - is formed from the fiberized fiber material (209) in a low-water fiber web manufacturing process, preferably at a continuous production rate of 300 m / min or greater; during the processing process c) the fiber material (200) is conveyed by a first conveying device (241) with a first mass flow; and d) the conveyed fiber material is then processed stepwise into fiberized fiber material (209) in at least a first fiberizing device (222) and a final fiberizing device (223); characterized by the fact that a first mass flow measuring device (101) is provided in the processing process, so that the first mass flow conveyed into the first fiberizing device (222) is detected and that the first conveying device (241) adjusts the conveyed first mass flow based on the detected first mass flow value.

2. Method according to claim 1 , characterized by the fact that The fiber material, which is progressively fiberized after leaving the first fiberizing device (222), is conveyed by a second conveying device (251) into the last fiberizing device (223) with a second mass flow.

3. Method according to claim 2, characterized by the fact that a second mass flow measuring device (102, 102') is provided downstream of the second conveying device (251), in particular downstream of the last fiberizing device, especially preferably directly on or downstream of the second conveying device (251), so that an emerging second mass flow is detected and that the second conveying device (251) adjusts the conveyed second mass flow based on the detected second mass flow value.

4. Method according to any one of claims 1 to 3, characterized by the fact that In the fiber web manufacturing process, a final mass flow measuring device (100) is provided, so that a final mass flow, preferably calculated from a measured basis weight, of the produced air-laid fiber web (309) is measured and the first conveying device (241) adjusts the conveyed first mass flow on the basis of the measured first mass flow value and the last mass flow value.

5. Method according to claims 2 and 4, characterized by the fact that The second mass flow of fiber material is conveyed in such a way that the second mass flow and the last mass flow of fiber material are essentially the same.

6. Method according to at least one of the preceding claims, characterized by the fact that The fiber material, which is gradually defibered, is temporarily buffered in an intermediate buffer (250) after leaving the first defiberizing device (222). is, in particular, the intermediate buffer (250) is included in a second conveying device (251).

7. Method according to claim 6, characterized by the fact that The intermediate buffer (250) thickens the progressively processed fiber material after it leaves the first fiberizing device (222) in an air separator, preferably by means of gravity and / or a belt press.

8. Method according to any one of claims 2 to 7, characterized by the fact that the first mass flow is set within a first fluctuation range of + / - 10%, in particular + / - 7.5%, preferably + / - 5%, relative to the last mass flow and / or the second mass flow is set within a second fluctuation range of + / -2%, in particular + / - 1.5%, preferably + / - 1%, and most preferably essentially the same, with respect to the last mass flow.

9. Machine for producing an air-laid fibrous web (309), in particular a dry-formed paper, cardboard or tissue web or a nonwoven web, from a fibrous material (200), in particular in the form of bales or sheets, in particular for carrying out the method according to claim 1, comprising: - a low-water fiber material processing plant (2); and - a fiber web manufacturing plant (3); the low-water fiber material processing plant (2) further comprises: - at least a first conveying device (241); and - at least a first (222) and last (223) fiberizing device; wherein the fiber web manufacturing plant (3) further comprises: - at least one forming device (4C); and - at least one solidification device (81, 83); and - a winding device (120); and - preferably a final mass flow measuring device (100); Furthermore, a superior control and regulating device (60) is included, which can be connected to the first conveying device (241), characterized by the fact that a first mass flow measuring device (101) is located upstream of the first fiberizing device (222) and is connectable to the higher-level control and regulating device (60), so that an operative connection with the first conveying device (241) is created.

10. Machine according to claim 9, characterized by the fact that a second conveying device (251) after the first fiberizing device (222) and before the last fiberizing device (223) and a second mass flow measuring device (102) is included and that the second mass flow measuring device (102) is connectable to that of the superior control and regulating device (60) so that an operative connection with the second conveying device (241) is created.

11. Machine according to claim 10, characterized by the fact that the second conveying device (251) comprises a belt press and / or a rotating shredding roller.

12. Machine according to one of claims 9 to 11 , characterized by the fact that the first conveying device (241) comprises a screw conveyor and / or a vibrating conveyor and / or a driven unwinding device.

13. Machine according to one of claims 11 to 12, characterized by the fact that the first mass flow measurement device (101) comprises an optical measurement system, preferably comprising an optical sensor and an evaluation device which uses artificial intelligence to detect the shape and size of the fiber material, preferably in the form of crushed chips.

14. Machine according to one of claims 11 to 12, characterized by the fact that the first mass flow measuring device (101) comprises a pressure measuring sensor, preferably arranged in or below a screw conveyor and / or a vibratory conveyor.

15. Machine according to one of claims 10 to 14, characterized by the fact that the second mass flow measuring device (102) an optical measuring system, preferably a measuring system based on light scattering, or a microwave-based measuring system or a measuring system based on a dielectric resistance.

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