Method and apparatus for producing highly dehydrated fluff pulp, and fluff obtained thereby

Abstract

The present invention relates to a method and an apparatus for producing a highly dehydrated fluff pulp passing through two to three dehydration zones in a structure connecting a dual former paper machine to a sheet forming station. This method comprises spraying said fibrous paste for fluff from an inlet box (2) onto a sheet forming station (11), in which a horizontal lower web (12) is arranged on a discontinuous drainage shoe (13), in which a first amount of water (100) is discharged downward through a first drainage zone (10a); and conveying the fibrous paste for partially dehydrated fluff to a dual former section (21) forming a second drainage zone (20a), sandwiching the paste between a lower web and a horizontal upper web (22) disposed below an upper discontinuous drainage shoe (23), in which a second amount of water (200) is removed upward by vacuum (50) through the upper web (22) and is removed downward by gravity through the lower web (12). A third discharge zone (30a) is provided comprising a pressure roller arranged above the fluff pulp, which moves along the paper forming table (11). The final water content of the obtained fluff pulp is 6-11%.

Description

Technical Field

[0001] This invention relates to a method for producing highly dehydrated fluff pulp (PFAD). Background Technology

[0002] Cellulose fluff pulp, also known as fluff pulp, defibrinated, fibrillated, fluffy pulp, or pulverized fluff pulp, refers to fluff pulp typically made from flakes or pads of cellulose fluff pulp. Cellulose fluff pulp, or fluff pulp, is a pulp in the form of cellulose flakes that is suitable for separation into cellulose fluff pulp.

[0003] Flock pulp, or its undecellulosed form, is a cellulose pulp that can be made from hardwood, softwood, or both, obtained from wood pulping. The properties of cellulose fibers can vary depending on the pulping process and the source of the cellulose fibers. Examples of hardwood species include birch, oak, beech, maple, and eucalyptus; examples of softwood species include hemlock, fir, pine, southern pine, radiata pine, slash pine, Douglas fir, white fir, Scandinavian pine, and Lodgepole fir.

[0004] Traditionally, the fluff pulp is drained on a forming table to obtain dried fluff pulp sheets.

[0005] Machines known as duo-formers are traditionally used in papermaking machines. Paper is a completely different material from fluff pulp because it contains additives such as carbonates, starch, gums, refined cellulose, dyes, etc., typically reaching 30% or more by weight in the paper. Examples of commercial duo-formers are Belbond® or duo-formers from Voith.

[0006] Unlike paper, fluff pulp is used in its pulverized form (thus forming fluff pulp) to make diapers and sanitary pads.

[0007] Traditionally, it was believed that using vacuum to dehydrate the upper surface of the cellulose fiber paste during the formation of the cellulose fluff web would result in a dry, dense surface. This would prevent further removal of moisture from the web formed by the paste, trapping moisture within the thick web and causing uneven moisture content along the formed fluff sheets, especially for fluff sheets with high basis weight or thickness.

[0008] Uneven drying can then lead to problems such as delamination of the formed fluff pulp flakes, agglomeration of the fluff pulp flakes after defibering, a reduced percentage of defibered fluff pulp, reduced integrity of the defibered fibers (manifested as a reduced breaking index of the fluff pad formed from the defibered fibers), and reduced specific absorption capacity of the pad when the absorbent core structure has been formed. These problems are exacerbated when hardwood is used in fluff pulp with shorter fibers.

[0009] Furthermore, differences in roughness are observed on the two surfaces of the sheet formed on the drainage net or felt, which is caused by the typical unilateral drainage of a fourdrinier paper machine. This can lead to even more uneven and complex fiber separation. Summary of the Invention

[0010] One object of the present invention is a method for producing highly dehydrated fluff pulp (PFAD), comprising:

[0011] The fiber paste (PFPF) for the pile is sprayed from the inlet box (2) onto the sheet forming table (11), and

[0012] Fiber paste (PFPF) for the pile is deposited onto a basic horizontal lower web (12), which is arranged on a basic horizontal discontinuous drainage boot (13) on a basic horizontal sheet forming table (11).

[0013] During the passage of the fiber paste (PFPF) for the pile through the first drainage zone (10a), a first amount of water (100) is removed downward from the fiber paste (PFPF) for the pile through the lower net (12).

[0014] The fiber paste (LPFPD) for partial dewatering of the fluff formed on the lower wire (12) of the paper machine is conveyed to the double forming section (20) formed by the double forming paper machine (21) and the paper forming table (11); the fiber paste (LPFPD) for partial dewatering of the fluff is sandwiched between the lower wire (12) and the upper wire (22).

[0015] The internet access (22) mentioned is basically horizontal internet access, arranged in

[0016] Basic level discontinuous upper drainage boot (23)

[0017] The lower and upper webs (12, 22) define a second drainage zone (20a) therebetween, which is used for additional drainage of partially dehydrated fiber paste (LPFPD) of fluff to form highly dehydrated fluff paste (PFAD).

[0018] The second drainage zone (20a) is located downstream of the first drainage zone (10a);

[0019] Fiber paste (LPFPD) for partially dehydrated fluff, sandwiched between the lower and upper webs (12, 22), is conveyed.

[0020] Enter the second drainage zone (20a)

[0021] This is so that during the movement of the nets (12, 22) along the second drainage zone (20a);

[0022] During the transport of the fiber paste (LPFPD) for partially dehydrated fluff along the second drainage zone (20a), a second amount of water (200) is removed upward from the fiber paste (LPFPD) for partially dehydrated fluff by the web (22) and downward by the lower web (12).

[0023] During the movement of the net (12, 22) along the upper boot (23), a portion of the water removed upwards by vacuum (50) is removed through the net (22);

[0024] The net (22) is connected to a vacuum source (50) so that the water removed upwards is removed upwards through the net (22) into the inverted box (56);

[0025] A portion of the water removed upwards is collected by vacuum openings (54) arranged in the double-former paper machine (21) on the opposite sides of the web (22) and the discontinuous upper drainage shoe (23);

[0026] And as the nets (12, 22) move along the lower boot (13), the portion of the water that is being removed downward is removed by gravity through the lower net (12);

[0027] The nets (12, 22) are moved to form and release highly dehydrated fluff pulp (PFAD) to obtain highly dehydrated fluff pulp (PFAD) with a moisture content of 6–11%.

[0028] Another object of the present invention is a drainage system for discharging fiber paste (PFPF) for fleece, the system comprising:

[0029] Sheet forming stage (11);

[0030] Dual-former papermaking machine (21);

[0031] The dual-former paper machine (21) together with the sheet forming table (11) forms a second drainage zone (20a).

[0032] Overlap the sheet forming stage (11);

[0033] In it

[0034] The first drainage zone (10a) removes an initial amount of water (100) downwards, and

[0035] The second drainage zone (20a) is located downstream of the first drainage zone (20a);

[0036] The second drainage zone removes a second amount of water (200) by gravity downwards and by vacuum upwards.

[0037] Another object of the present invention is an apparatus for discharging fiber paste (PFPF) for fluffing, the apparatus comprising:

[0038] Sheet forming stage (11);

[0039] Dual-former papermaking machine (21);

[0040] The sheet forming stage (11) includes a first drainage zone (10a) and a second drainage zone (20a).

[0041] A dual-former paper machine (21) is arranged on the sheet forming table (11) in the second drainage zone (20a);

[0042] The dual-former paper machine (21) includes a vacuum opening (54), wherein the upward-facing vacuum opening (54) removes water from the fiber paste (PFPF) for fluffing and directs the removed water upward into the inverted box (56). Attached Figure Description

[0043] Figure 1 This is a perspective view of the method of the present invention.

[0044] Figure 2 This is a view of the first drainage zone of the present invention.

[0045] Figure 3 This is a close-up view of the drainage area of ​​the present invention.

[0046] Figure 4 This is a close-up view of the first drainage zone of the present invention.

[0047] Figure 5 This is a view of the second drainage zone of the present invention. Detailed Implementation

[0048] The present invention relates to a method for producing highly dehydrated fluff pulp (PFAD) and the fluff pulp obtained therefrom.

[0049] The fluff pulp according to the invention can be used in absorbent articles and hygiene products, wherein the fluff pulp is commonly used to form the absorbent core in baby diapers, incontinence products and feminine hygiene pads.

[0050] Fiber separation of cellulose fluff pulp flakes can be achieved using hammer mills, saws, and / or pin shredders. Traditional methods utilize, for example, a series of high-speed rotating saws, needles, or small hammers to separate the cellulose fluff pulp flakes into loose, individual fibers, thus forming fluff pulp. The fluff pulp fibers are then fed into an absorbent core forming system. Poor fiber separation of the cellulose fluff pulp flakes can lead to the formation of undesirable clumps or knots.

[0051] Typically, once the cellulose fluff pulp sheet has been defibered (i.e., forming defibered cellulose fluff pulp), it is fed into a forming wheel with receiving bags that thus form the absorbent core of the cellulose fluff pulp, receiving a certain amount of compression in the cellulose fluff pulp deposited there. Alternatively, the fiber-separated cellulose fluff pad is placed on a moving belt, for example, on a moving coarse screen, or on a moving felt, and vacuum-assistedly deposited onto a lower forming screen to form a cellulose fluff pad, which can be cut and sandwiched between a nonwoven fabric and a plastic or polymer sheet liner to form an absorbent diaper core for infants. In both cases, a superabsorbent polymer (SAP) can be introduced into the fluff pulp during the formation of the absorbent core, before sandwiching. Such a product can be produced by methods known in the art. For example, an absorbent core with fluff pulp can be combined with superabsorbent polymers (SAPs), such as starch-acrylonitrile copolymers, hydrolyzed starch-acrylonitrile copolymers, acrylic (co)polymers, acrylamide (co)polymers, polyvinyl alcohol, polyacrylate / polyacrylamide copolymers, polyacrylic (co)polymers, sodium polyacrylate, ethylene maleic anhydride copolymers, crosslinked carboxymethyl cellulose, polyvinyl alcohol copolymers, polyethylene oxide, crosslinked polyethylene oxide and starch-grafted polyacrylonitrile copolymers, their salts, and combinations thereof.

[0052] The use of cellulose fluff pulp in hygiene products or sanitary pads requires that the fluff pulp be hypoallergenic, which is achieved by using little or no fillers, sizing agents, dyes or pigments, or any other compounds other than cellulose fibers.

[0053] The cellulose fluff pulp or fluff pulp for defiberization can be produced on a paper machine, such as a fourdrinier paper machine or any other suitable paper machine known in the art, and the methods for producing fluff pulp on various paper machines are well known in the art. Typically, the cellulose pulp paste (PFPF) for fluffing can be a relatively low-consistency water-containing pulp fiber paste, for example, about 1% by weight, and the cellulose pulp paste (PFPF) for fluffing is uniformly sprayed from the outlet box onto a forming table having a porous forming belt or annular forming mesh, wherein water from the cellulose pulp paste (PFPF) for fluffing is gradually drained downward by gravity or optionally by means of vacuum through tiny openings in the forming mesh or porous belt until a mesh pad of pulp fibers is formed on the forming mesh or forming belt.

[0054] Typically, the still-wet fiber web (drained fluff pulp) is transferred from the forming web or forming belt to a wet press, which usually has pressure rollers that press the still-wet fiber web (drained fluff pulp) to further reduce its moisture content. The web is then subjected to a downstream drying section to remove most or most, or even substantially all, of the moisture still remaining from the forming sheet and to further consolidate the fibers into a web. After drying, the dried web or fluff pulp can be further wound into rolls to form fluff pulp rolls, or it can be cut into sheets and stacked to form fluff pulp bales.

[0055] Compared to existing technologies that only present a forming stage, the method for producing highly dehydrated fluff pulp (PFAD) obtained by the present invention provides fluff pulp with uniform dryness and uniform specific volume.

[0056] Therefore, one object of the present invention is a method for producing highly dehydrated fluff pulp (PFAD), comprising:

[0057] The fiber paste (PFPF) for the pile is sprayed from the inlet box (2) onto the sheet forming table (11), and

[0058] Fiber paste (PFPF) for the pile is deposited onto a basic horizontal lower web (12), which is arranged on a basic horizontal discontinuous drainage boot (13) on a basic horizontal sheet forming table (11).

[0059] During the passage of the fiber paste (PFPF) for the pile through the first drainage zone (10a), a first amount of water (100) is removed downward from the fiber paste (PFPF) for the pile through the lower net (12).

[0060] The fiber paste (LPFPD) for partial dewatering of the fluff formed on the lower wire (12) of the paper machine is conveyed to the double forming section (20) formed by the double forming paper machine (21) and the paper forming table (11); the fiber paste (LPFPD) for partial dewatering of the fluff is sandwiched between the lower wire (12) and the upper wire (22).

[0061] The internet access (22) mentioned is basically horizontal internet access, arranged in

[0062] Basic level discontinuous upper drainage boot (23)

[0063] The lower and upper webs (12, 22) define a second drainage zone (20a) therebetween, which is used for additional drainage of partially dehydrated fiber paste (LPFPD) of fluff to form highly dehydrated fluff paste (PFAD).

[0064] The second drainage zone (20a) is located downstream of the first drainage zone (10a);

[0065] Fiber paste (LPFPD) for partially dehydrated fluff, sandwiched between the lower and upper webs (12, 22), is conveyed.

[0066] Enter the second drainage zone (20a)

[0067] This is so that during the movement of the nets (12, 22) along the second drainage zone (20a);

[0068] During the transport of the fiber paste (LPFPD) for partially dehydrated fluff along the second drainage zone (20a), a second amount of water (200) is removed upward from the fiber paste (LPFPD) for partially dehydrated fluff by the web (22) and downward by the lower web (12).

[0069] During the movement of the net (12, 22) along the upper boot (23), a portion of the water removed upwards by vacuum (50) is removed through the net (22);

[0070] The net (22) is connected to a vacuum source (50) so that the water removed upwards is removed upwards through the net (22) into the inverted box (56);

[0071] A portion of the water removed upwards is collected by vacuum openings (54) arranged in the double-former paper machine (21) on the opposite sides of the web (22) and the discontinuous upper drainage shoe (23);

[0072] And as the nets (12, 22) move along the lower boot (13), the portion of the water that is being removed downward is removed by gravity through the lower net (12);

[0073] The nets (12, 22) are moved to form and release highly dehydrated fluff pulp (PFAD) to obtain highly dehydrated fluff pulp (PFAD) with a moisture content of 6–11%.

[0074] Figure 1 The connection between the dual-former paper machine (21) and the sheet forming table (11) is shown, which can be achieved by overlapping the sheet forming table (11) onto the sheet forming table (11) and aligning it with the sheet forming table (11).

[0075] The sheet forming stage (11) of the method for producing highly dehydrated fluff pulp (PFAD) may further include a third drainage zone (30a). The third drainage zone (30a) may include at least one pressure roller arranged above the highly dehydrated fluff pulp (PFAD) moving along the sheet forming stage (11), and the at least one pressure roller squeezes the highly dehydrated fluff pulp (PFAD) and removes water from the highly dehydrated fluff pulp (PFAD) by a lower screen (12) arranged on the sheet forming stage (11), thereby forming fluff pulp sheets (FPF).

[0076] Fiber paste for fluffing (PFPF) from the high dehydration fluff pulp (PFAD) production process can be discharged from the inlet box (2). The fiber paste for fluffing (PFPF) has a consistency of 0.5-2%.

[0077] The fiber paste (PFPF) for fluffing produced from highly dehydrated fluff pulp (PFAD) can be conveyed downstream at an average speed of 60 m / min.

[0078] The wire (12) from the process of producing highly dehydrated fluff pulp (PFAD) can be looped in the sheet forming table (11), and the wire (22) can be looped in the double former paper machine (21).

[0079] The method may also include a vacuum opening (54), which may be located directly above or in contact with the fiber paste (LPFPD) for partially dehydrated fluff in the second drainage zone (20a). The vacuum opening (54) may provide a vacuum (50) applied to the fiber paste (LPFPD) for partially dehydrated fluff, which may be 0-6 mCa. The method also includes a net (22), which may move in the same direction and at the same speed as the lower net (12).

[0080] A fluff pulp sheet (FPF) is provided by a method for the purpose of this invention, characterized by a strength of 600-800 g / m³. 2 The specific volume is at least 0.6-0.8 g / cm³. 2 The thickness is 800-1000 micrometers, the width is 3-4 meters, and the preferred weight is 650-750 cm³. 2 .

[0081] When fiber separation is performed, the fluff pulp flakes (FPF) obtained by this invention produce fluff pulp with a knot percentage of less than 9%, typically requiring a fiber separation energy of less than 45 kWh / t. Knots are clumps and pulp fragments from the fluff pulp flakes that are not completely broken up during fiber separation. Knots are defined herein as the fraction of defiberized fluff pulp retained on an ASTM 12-mesh sieve. The knot percentage is a measure of the number of knots retained in the mesh compared to the original amount of pulp to be separated. Fiber separation energy is typically the energy (in kilojoules) required to separate one kilogram of cellulose fibers in dry flake form during the process of breaking down dry cellulose flakes into individual fibers.

[0082] In the production of highly dehydrated fluff pulp (PFAD), fiber paste (LPFPD) for partially dehydrated fluff is fed from the first drainage zone (20a) to the second drainage zone (20a) at a concentration of 1.5-3%, and highly dehydrated fluff pulp (PFAD) is fed from the second drainage zone (20a) to the third drainage zone (30a) at a concentration of 15-17%.

[0083] Fleece pulp sheets (FPF) can be made from bleached hardwood pulp (BEKP).

[0084] After drying, the resulting fluff pulp sheets (FPF) can be wound onto a roller to form a cellulose fluff pulp roll, or they can be cut into sheets and stacked to form cellulose fluff pulp bales. For example, fluff pulp sheets (FPF) can preferably be wound onto a roller (60).

[0085] Another object of the present invention is to provide a drainage system for discharging fiber paste (PFPF) for fluffing, the system comprising:

[0086] A sheet forming stage (11); including a first drainage zone (10a) and a second drainage zone (20a).

[0087] Sheet forming stage (11);

[0088] Dual-former papermaking machine (21);

[0089] The dual-former paper machine (21) together with the sheet forming table (11) forms a second drainage zone (20a).

[0090] Overlap the sheet forming stage (11);

[0091] In it

[0092] The first drainage zone (10a) removes an initial amount of water (100) downwards, and

[0093] The second drainage zone (20a) is located downstream of the first drainage zone (20a);

[0094] The second drainage zone removes a second amount of water (200) by gravity downwards and by vacuum upwards.

[0095] Another object of the present invention is an apparatus for discharging fiber paste (PFPF) for fluffing, the apparatus comprising:

[0096] Sheet forming stage (11);

[0097] Dual-former papermaking machine (21);

[0098] The sheet forming stage (11) includes a first drainage zone (10a) and a second drainage zone (20a).

[0099] A dual-former paper machine (21) is arranged on the sheet forming table (11) in the second drainage zone (20a);

[0100] The dual-former paper machine (21) includes a vacuum opening (54), wherein the upward-facing vacuum opening (54) removes water from the fiber paste (PFPF) for fluffing and directs the removed water upward into the inverted box (56).

[0101] The methods, systems, or apparatus of the present invention provide improved drying / draining rates for fiber paste (FPS) for fluffing on a sheet forming table (11). For example, to achieve the drainage process of dried fluff pulp sheets (FPF) with an average water content of 7% using only a sheet forming table (11) (prior art operation), a sheet forming table (11) up to 25 meters long can be used. With the methods and systems of the present invention, the typical length of the sheet forming table (11) can be reduced. Alternatively, production can be increased. For example, by attaching a double-former paper machine (21) to the sheet forming table (11), wherein the double formers (21) overlap and align above the sheet forming table (11), the drainage process, system, and apparatus of the present invention not only does not negatively affect the quality of the fluff pulp but also improves quality even when operating with a shortened table. Prior art operation using only a forming table (e.g., an Andritz forming table) results in an average production rate of 57.1 m / min. The methods, systems, and apparatus of the present invention produce an average production rate of 58.3 m³ / min. Therefore, the methods, systems, and apparatus of the present invention allow for an increase in drainage rate of 1.5 m / min, with a direct overall impact on productivity equivalent to 2.7% of annual output.

[0102] Furthermore, it is believed that the double-former paper machine (21), connected to the sheet-forming table (11), substantially removes the water inherent to the cellulose fibers. Inherent water is water present within the cellulose fibers and is not as easily removed as external water; it can vary considerably depending on the fiber's origin. By utilizing the purposes of this invention, external water is also removed, providing shorter drainage operations, or alternatively, fluff pulp with lower water content, or alternatively, higher productivity—all three factors can occur simultaneously. The water content obtained using only the sheet-forming table (11) in fluff pulp production results in an average water content of 7.7% by weight. The methods, systems, and apparatus of this invention result in an average water content of 7.32% w / w, with a 5.6% reduction in water content in the fluff pulp.

[0103] The fluff pulp flakes obtained in this paper preferably have a content of 600-800 g / m³. 2 The density of fluff pulp. For example, the properties of fluff pulp are generated by parameters of the fluff pulp sheet forming device, such as consistency, screen outlet speed control, inlet box temperature, inlet box jet flow rate, and other operations, such as steam application, distribution along the fluff pulp forming table and fiber fluff pulp web; the application of drying cylinders; and other parameters, such as—unlike common cellulose pulp—using airflow for drying. These prior art operations result in fluff pulp sheets that traditionally achieve 85-95% fiber separation and a breaking strength of 500-950 kPa.

[0104] Reduced tensile strength leads to problems such as breakage of absorbent cores in diapers and sanitary pads. A broken absorbent core is detrimental to the normal function of baby diapers, causing leaks and requiring replacement, thus shortening the lifespan of the hygiene products.

[0105] By using the methods, systems, and apparatus of this invention, high fiber separation rates can be maintained even with, for example, a shortened forming table. For the fluff pulp sheets (FPF) obtained herein, the crushing rate is typically 85-95%.

[0106] Similarly, even when the fluff pulp flakes (FPF) of the present invention are obtained with a shorter drainage length, the breaking index remains safe. For example, the cellulose fluff pulp of the present invention has a breaking index in the range of 600-800 kPa.

[0107] Furthermore, fluff pulp sheets (FPF) do not delaminate or become brittle. For fluff used for partial dehydration (LPFPD), the dehydration or drainage is uniform throughout the fiber paste, resulting in highly dehydrated fluff pulp (PFAD) and thus uniformly drained fluff pulp sheets (FPF) with a uniform dry water content not only on the surface but also throughout the entire mass.

[0108] Similarly, the present invention also provides a reduced breakage rate in the resulting fluff pulp flakes (FPF). Prior art operations produce fluff pulp with a breakage index of 726.3 kPa, while the methods, systems, and apparatus of the present invention produce fluff pulp flakes (FPF) with a breakage index of 705.02 kPa. Fiber separation of the fluff pulp flakes (FPF) is unaffected; prior art operations, using only a sheet forming table (11), typically produce fluff pulp with a fiber separation index of 96.7%, while the processes, systems, and apparatus of the present invention produce fluff pulp flakes (FPF) with a fiber separation index of 95.9%, a statistically significant difference. Using only a sheet forming table, the specific absorption capacity of fluff pulp from prior art operations is 1.33 s / g, while using the methods, systems, and apparatus of the present invention, it is 1.32 s / g, with a maximum of 1.5 s / g. The obtained basis weight was further increased from 702.2 g / mm² to 706.6 g / mm², and the thickness was reduced from 944.93 mm to 937.4 mm, resulting in a more compact roll for transport.

Claims

1. A method for producing highly dehydrated fluff pulp (PFAD), characterized in that... It includes: The fiber paste (PFPF) for the pile is sprayed from the inlet box (2) onto the sheet forming table (11), and Fiber paste (PFPF) for the pile is deposited onto a basic horizontal lower web (12), which is arranged on a basic horizontal discontinuous drainage boot (13) on a basic horizontal sheet forming table (11). During the passage of the fiber paste (PFPF) for the pile through the first drainage zone (10a), a first amount of water (100) is removed downward from the fiber paste (PFPF) for the pile through the lower net (12). The fiber paste (LPFPD) for partial dewatering of the fluff formed on the lower wire (12) of the paper machine is conveyed to the double-former section (20) formed by the double-former paper machine (21) and the paper forming table (11); the fiber paste (LPFPD) for partial dewatering of the fluff is sandwiched between the lower wire (12) and the upper wire (22). The internet access (22) is essentially horizontal, arranged below a discontinuous upper drainage boot (23) at a basic horizontal level. The lower and upper webs (12, 22) define a second drainage zone (20a) therebetween, which is used for additional drainage of partially dehydrated fiber paste (LPFPD) of fluff to form highly dehydrated fluff paste (PFAD). The second drainage zone (20a) is located downstream of the first drainage zone (10a); Fiber paste (LPFPD) for partial dehydration of fluff sandwiched between the lower net and the upper net (12, 22) is conveyed into the second drainage zone (20a) so that during the movement of the net (12, 22), it flows along the second drainage zone (20a). During the transport of the fiber paste (LPFPD) for partially dehydrated fluff along the second drainage zone (20a), a second amount of water (200) is removed upward from the fiber paste (LPFPD) for partially dehydrated fluff by the web (22) and downward by the lower web (12). During the movement of the net (12, 22) along the upper boot (23), a portion of the water removed upwards by vacuum (50) is removed through the net (22); The net (22) is connected to a vacuum source (50) so that the water removed upwards is removed upwards through the net (22) into the inverted box (56); A portion of the water removed upwards is collected by vacuum openings (54) arranged in the double-former paper machine (21) on the opposite sides of the web (22) and the discontinuous upper drainage shoe (23); And as the nets (12, 22) move along the lower boot (13), the portion of the water that is being removed downward is removed by gravity through the lower net (12); The nets (12, 22) are moved to form and release highly dehydrated fluff pulp (PFAD) to obtain highly dehydrated fluff pulp (PFAD) with a moisture content of 6–11%.

2. The method according to claim 1, characterized in that, The sheet forming stage (11) also includes a third drainage zone (30a).

3. The method according to claim 1, characterized in that, The third drainage zone (30a) includes at least one pressure roller arranged above the highly dehydrated fluff pulp (PFAD) moving along the sheet forming table (11). At least one pressure roller arranged on the sheet forming table (11) squeezes the highly dehydrated fluff pulp (PFAD) moving along the sheet forming table (11) and removes water from the highly dehydrated fluff pulp (PFAD) through the lower screen (12). Forming fluff flakes (FPF).

4. The method according to claim 1, characterized in that, The fiber paste (PFPF) for the pile is discharged from the inlet box (2), wherein the fiber paste (PFPF) for the pile has a consistency of 0.5-2%.

5. The method according to claim 1, characterized in that, The fiber paste (PFPF) for the pile is conveyed downstream at an average speed of 60 m / min.

6. The method according to claim 1, characterized in that, The lower wire (12) is looped in the sheet forming table (11), and the upper wire (22) is looped in the double forming paper machine (21).

7. The method according to claim 1, characterized in that, The vacuum (50) is 2-6 mCa.

8. The method according to claim 1, characterized in that, The vacuum opening (54) is located directly above the fiber paste (LPFPD) for partially dehydrated fluff in the second drainage zone (20a).

9. The method according to claim 1, characterized in that, The internet access (22) moves in the same direction and at the same speed as the internet disconnection (12).

10. The method according to claim 1, characterized in that, The basis weight of the fluff pulp (FPF) is 600-800 g / m³. 2 .

11. The method according to claim 1, characterized in that... The fluff pulp (FPF) contains at least 0.6-0.8 g / cm³. 3 The specific volume.

12. The method according to claim 1, characterized in that... The fluff pulp sheet (FPF) comprises a sheet with a thickness of 800-1000 micrometers.

13. The method according to claim 1, characterized in that, The fluff pulp sheet (FPF) comprises a sheet with a width of 3-4 m.

14. The method according to claim 10, characterized in that, The fluff pulp sheets (FPF) comprise 670-760 g / m³. 2 The film.

15. The method according to claim 1, characterized in that, Fiber paste (LPFPD) for partially dehydrated fluff is fed from the first drainage zone (20a) to the second drainage zone (20a) with a consistency of 1.5-3%.

16. The method according to claim 1, characterized in that... The highly dehydrated fluff pulp (PFAD) is fed from the second drainage zone (20a) to the third drainage zone (30a) with a consistency of 15-17%.

17. The method according to claim 1, characterized in that... The fluff pulp sheet (FPF) contains BEKP.

18. The method according to claim 1, characterized in that, The fluff pulp sheet (FPF) is wound onto the roller (60).

19. A fluff pulp, characterized in that, It is obtained by the method defined in claim 1.

20. A drainage system for draining fiber paste (PFPF) used for pile, characterized in that, The drainage system includes: A sheet forming stage (11); including a first drainage zone (10a) and a second drainage zone (20a). Sheet forming stage (11); Dual-former papermaking machine (21); The dual-former paper machine (21) together with the sheet forming table (11) forms a second drainage zone (20a). Overlap the sheet forming stage (11); In this process, the first drainage zone (10a) removes an initial amount of water (100) downwards, and The second drainage zone (20a) is located downstream of the first drainage zone (20a); The second drainage zone removes a second amount of water (200) by gravity downwards and by vacuum upwards.

21. An apparatus for draining fiber paste (PFPF) used for pile, characterized in that, The device includes: Sheet forming stage (11); Dual-former papermaking machine (21); The sheet forming stage (11) includes a first drainage zone (10a) and a second drainage zone (20a). The dual-former paper machine (21) is arranged on the sheet forming table (11) in the second drainage zone (20a); The dual-former paper machine (21) includes a vacuum opening (54), wherein the upward-facing vacuum opening (54) removes water from the fiber paste (PFPF) for fluffing and directs the removed water upward into the inverted box (56).

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