Apparatus and method for manufacturing fiberboard

Abstract

The invention relates to a method for manufacturing fibreboard, in which fibres are formed into a first mixture with steam, which is fed to a dryer (4) through a blowing line (3). The invention is characterized in that after the refiner (2) and before the dryer (4), a post fibre feed (5) is fed into the blowing line (3) according to the principle of a jet pump. The invention also relates to an apparatus for manufacturing fibreboard, which allows the fibres and the post fibre to be mixed advantageously and sufficiently.

Description

Technical Field

[0001] This invention relates to a method for manufacturing fiberboard, particularly medium-density fiberboard (MDF) or high-density fiberboard (HDF), wherein lignocellulosic material (e.g., annual plants or wood, for example in the form of sawdust or wood chips) is cooked in a digester and then decomposed into fibers in a refiner, wherein the fibers form a first mixture with steam, the mixture exits the refiner at a first pressure, and is supplied to a dryer via a blower line. The invention also relates to an apparatus for manufacturing fiberboard, particularly medium-density fiberboard (MDF) or high-density fiberboard (HDF), comprising a digester for cooking the lignocellulosic fibrous material (e.g., annual plants or wood), a refiner for decomposing the material into fibers, and a dryer for drying the fibers, wherein the refiner and the dryer are connected via a blower line. Background Technology

[0002] In the manufacture of fiberboard (particularly medium-density fiberboard), fibers and steam are blown out of a refiner as a first mixture under a first pressure during the drying process and guided through a blow line to a dryer operating without pressure (i.e., at atmospheric pressure). Here, the bonding of the fibers (particularly wood fibers) takes place within the blow line. This apparatus is known to those skilled in the art, for example, from EP3027806 A1, which discloses a device for continuously discharging steam between the refiner and the dryer, as well as a device for bonding.

[0003] WO 2021176326 A1 discloses a method for manufacturing particleboard, medium-density fiberboard or high-density fiberboard, the method comprising recycling particleboard, medium-density fiberboard and / or high-density fiberboard materials, wherein the recycled fragments and / or recycled wood fibers are provided as starting materials in the production process of particleboard, medium-density fiberboard or high-density fiberboard (preferably in a dry production process).

[0004] WO 2023031763 A1 discloses a method for manufacturing wood fiberboard, wherein recycled wood fiberboard is converted into recycled wood fibers; and wherein the recycled wood fibers are preferably supplied to the production line as starting material in a dry production method for manufacturing wood fiberboard.

[0005] DE 202016101394 U1 discloses a jet pump for loosening and separating wood fibers, wherein the wood fibers are supplied to the jet pump through a suction nozzle; and the wood fibers encounter a propulsion medium at the outlet of a propulsion nozzle arranged within the jet pump and are accelerated by this propulsion medium.

[0006] Adding post-fibers (such as fibers recovered from medium-density fiberboard (MDF) or high-density fiberboard (HDF), or alternative fibers such as those from annual plants) during the manufacturing process is increasingly becoming a goal. It is suggested that these post-fibers be blended into the fibers (especially fresh wood fibers), and that the mixture be fed as a raw material into the conventional manufacturing process. Alternatively, it is suggested that the post-fibers be introduced directly into the dryer. Both approaches are based on the concept of introducing post-fibers into the manufacturing process under pressureless conditions, which can be easily achieved. Conversely, the direct addition of post-fibers to pressurized areas (such as refiners) should be avoided, as this is technically and energy-intensive, and requires overcoming high pressure differentials. Adding under pressure can lead to agglomeration of the post-fibers, or insufficient pressure sealing, resulting in flow failures and ultimately equipment shutdown. Typically, these approaches fail to achieve proper blending of the fibers with the post-fibers. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide an apparatus and method in which post-added fibers can be safely and effectively introduced into the method or apparatus. Another technical problem to be solved by the present invention is to achieve thorough mixing of the fiber and the post-added fiber.

[0008] According to the invention, the aforementioned technical problem is solved by supplying post-added fibers into the blow line after the refiner and before entering the dryer. The post-added fibers advantageously comprise scrap and / or recycled fibers from recycled fiberboard (particularly particleboard, medium-density fiberboard, and / or high-density fiberboard), or alternative fibers, such as fibers from annual plants, and are optimally suited for fiberboard (particularly medium-density fiberboard (MDF) or high-density fiberboard (HDF)) remanufacturing. Therefore, the post-added fibers are also advantageously derived from lignocellulosic fiber materials. Surprisingly, the introduction of post-added fibers according to the invention, on the one hand, allows for excellent mixing of the fibers and post-added fibers due to the high velocity and favorable turbulence formed within the blow line; on the other hand, the introduction of post-added fibers into the blow line is advantageous because the post-added fibers do not degrade, shorten, etc., between the feed point and the dryer, and are particularly not cooked or ground.

[0009] A particularly advantageous method has been shown to be feeding the blow-through line at a second pressure, which is closer to the dryer pressure than the first pressure. Compared to feeding at the first pressure, when feeding at a pressure closer to the dryer pressure (which typically operates at atmospheric pressure), a large portion of the first pressure has been converted into kinetic energy, i.e., the first mixture comprising steam and fibers flows at a correspondingly high velocity. On the other hand, feeding at this second pressure is advantageous because the subsequent fiber addition only needs to reach a correspondingly lower pressure level compared to the first pressure. Advantageously, the first pressure is particularly between 4 bar and 10 bar overpressure, and the second pressure is particularly at a maximum of 3 bar overpressure, preferably at a maximum of 2.0 bar overpressure, and particularly preferably at a maximum of 0.5 bar overpressure.

[0010] Corresponding to the method according to the invention, the added fiber forms a second mixture with steam and / or air, and is supplied to the feed point via a second blow line. The feeding of the second mixture results in particularly effective mixing with the first mixture, and particularly better mixing than when the added fiber is fed alone (e.g., via a rotary valve). Guiding the added fiber within a dedicated second blow line further allows for the separate addition of chemical agents, tailored specifically to the needs of the added fiber. Introducing the second mixture as a mixture of added fiber and air at a lower second pressure, particularly at a second pressure with a maximum overpressure of 0.2 bar, is technically feasible.

[0011] According to the present invention, the feeding of the second mixture is based on the principle of a jet pump, wherein the first mixture is supplied to the mixing chamber as a propellant, and the second mixture is supplied to the mixing chamber as a suction medium. Surprisingly, the momentum of the first mixture acting as a propellant within the mixing chamber of the jet pump can be used to draw the second mixture into the mixing chamber as a suction medium. Here, the first mixture, comprising fibers and steam, is supplied to the mixing chamber via a blow line, while the second mixture, comprising added fibers and steam and / or air, is supplied to the mixing chamber via a second blow line. Therefore, energy-efficient feeding is achieved on the one hand, and the mixing chamber of the jet pump device is allowed to effectively mix the first and second mixtures on the other.

[0012] In a particularly advantageous first embodiment of the method of the invention, the pressure of the second mixture is increased by a pressurizing device before feeding, wherein a mixture comprising post-added fibers and steam and / or air is supplied to the pressurizing device.

[0013] In an alternative advantageous embodiment of the method of the invention, before the second mixture is formed, the pressure of steam and / or air is increased by a pressurizing device, then the added fibers are mixed with steam and / or air, and the second mixture is supplied to the feed point through a second blowing line.

[0014] In both cases, the pressurization device can be designed as passive, i.e., a mixer for mixing pressurized air or pressurized steam, or it can be designed as active, i.e., a blower, fan, compressor, etc. In cases involving a second mixture of added fibers and air, a blower or fan is recommended, where the blower or fan allows only a slight pressure increase, specifically a maximum overpressure of 0.2 bar.

[0015] Similarly, in both cases, the added fibers can be mixed, for example, by a refiner, fiber separator, rotary valve feeder, screw or similar equipment.

[0016] One particularly advantageous method is to bond the fibers after the refiner and then feed the additional fibers after the bonding process. This ensures sufficient residence time for the fibers between the bonding site and the dryer. To bond the fibers, adhesive and air and / or steam are specifically supplied to a dual-material nozzle to achieve advantageous atomization and effective adhesive application. Another advantageous method is to bond the additional fibers before feeding. This is advantageous when the amount of the second mixture is increased relative to the amount of the first mixture. In this case, bonding only the fibers of the first mixture would result in "over-adhesion," which is neither effective nor meets quality requirements. Fiber bonding before feeding can be carried out, for example, in a second blowing line, such as through the aforementioned dual-material nozzle, and allows the additional fibers to be bonded specifically in a controlled manner in the second mixture. Alternatively, bonding can also be carried out during the mixing of the additional fibers into the second blowing line, i.e., for example, in a refiner, fiber separator, rotary valve feeder, screw, or similar equipment.

[0017] Another advantageous method is to separate a portion of the steam from the first mixture after the refiner and before the feed, and to supply the feed along with the added fibers. After this separation, the first mixture, which further contains fibers and a small amount of steam, is then supplied to the feed. A portion of the steam separated from the blow line advantageously forms a second mixture with the added fibers, and is also supplied to the feed through a second blow line. This allows for particularly efficient steam utilization.

[0018] The present invention also relates to an apparatus for manufacturing fiberboard (particularly medium-density fiberboard (MDF) or high-density fiberboard (HDF)), said apparatus comprising a cooker for cooking lignocellulosic cellulose fibrous materials (e.g., annual plants or wood, for example in the form of sawdust or wood chips), a refiner for breaking down the fibrous material into fibers, and a dryer for drying the fibers, wherein the refiner and the dryer are connected via a blower line. According to the invention, a feeding device for feeding post-added fibers into the blower line is arranged between the refiner and the dryer. As explained above regarding the method according to the invention, this apparatus allows for efficient and good mixing of the fibers and post-added fibers, wherein a decline in the quality of the post-added fibers is prevented.

[0019] According to a preferred embodiment of this equipment, the feeding device is arranged such that, during operation, the feeding into the blow line is carried out under the pressure of the blow line, and this pressure is closer to the pressure of the dryer than the pressure of the refiner. This allows for feeding at high speeds of the corresponding first mixture, wherein a relatively small pressure rise is sufficient to feed the added fibers.

[0020] In an embodiment of the device according to the invention, the feeding device is configured as a jet pump and includes a mixing chamber. One end of the feeding device is connected to a refiner via a blow line, and the other end is connected to a second blow line designed for providing post-fibers. A first mixture comprising steam and fibers, as a propellant, is supplied to the mixing chamber via the blow line, while a second mixture comprising steam and / or air and post-fibers, as a suction medium, is supplied to the mixing chamber via the second blow line. Thus, the momentum of the first mixture can be used to draw the second mixture into the mixing chamber of the jet pump, thereby achieving effective and thorough mixing of the first and second mixtures. The mixture (containing fibers and post-fibers) subsequently entering the dryer is nearly homogeneous.

[0021] In a particularly advantageous device, the feeding device is configured as a cyclone separator, comprising an inlet, an immersion pipe, a conical region, and an outlet. A blow line is connected to or constitutes the immersion pipe, and a first mixture is supplied to the feeding device through the immersion pipe. A second mixture is supplied to the feeding device circumferentially through the inlet via a second blow line. The immersion pipe extends to the conical region, and a mixing chamber is designed to be located in the conical region between the immersion pipe outlet and the (cyclone separator) outlet. Here, the immersion pipe may include nozzles in the region of the immersion pipe outlet, or be designed as nozzles, to further accelerate the first mixture before it enters the mixing chamber. Designing the feeding device as a cyclone separator generally allows for easy integration of a jet pump into the blow line. By introducing the second mixture through the inlet along the circumference of the cyclone separator, the second mixture is uniformly distributed on the periphery of the cyclone separator and, particularly, uniformly supplied to the mixing region on the periphery, which in turn results in good mixing of the first and second mixtures in the mixing region. According to a particularly advantageous embodiment, to regulate the amount of the second mixture that can be introduced into the mixing chamber, the immersion tube outlet can be positioned relative to the outlet, particularly along the axial direction of the mixing chamber or cyclone separator. Here, the axial positioning of the immersion tube outlet relative to the outlet or the conical region can be achieved by simply moving the immersion tube or the blowing line. In this way, the open annular cross-section between the conical region and the immersion tube can be effectively affected or regulated, and thus the amount of the second mixture introduced into the mixing chamber can be affected or regulated.

[0022] In another embodiment of the device according to the invention, a pressurizing device for increasing the pressure of the second mixture is arranged on the second blowing line, or alternatively, the pressurizing device is located upstream of the point where the fiber is added in the second blowing line. The pressurizing device can be designed as an active blower, fan, compressor, etc., or it can be designed as a passive mixer, i.e., a mixer for mixing pressurized air or pressurized steam. For example, the fiber is added after mixing by a pulper, fiber separator, rotary valve feeder, screw, or similar equipment.

[0023] In an equally advantageous apparatus, a first bonding device for bonding fibers is arranged in a blow line after the refiner and before the feed device, and optionally a second bonding device for bonding post-added fibers is arranged upstream of the feed device in a second blow line.

[0024] In a similarly advantageous apparatus, a separator is arranged in a blowing line between the refiner and the feed device for separating a portion of the steam from the first mixture, wherein the separated steam portion can be supplied to the feed device along with the added fibers. After the separator, the first mixture also includes fibers and a small amount of steam, and is supplied to the feed device via the blowing line. The steam portion separated from the blowing line advantageously forms a second mixture together with the added fibers, and is supplied to the feed device via a second blowing line. Attached Figure Description

[0025] The invention will now be described by way of example with reference to the accompanying drawings.

[0026] Figure 1 The diagram shows a machine for manufacturing fiberboard (particularly medium-density fiberboard (MDF) or high-density fiberboard (HDF)) according to the prior art.

[0027] Figure 2 A machine for manufacturing fiberboard (particularly medium-density fiberboard (MDF) or high-density fiberboard (HDF)) according to the present invention is shown.

[0028] Figure 3 A feeding device according to the invention is shown, wherein the feeding device is designed as a cyclone separator.

[0029] Figure 4 Another machine for manufacturing fiberboard (particularly medium-density fiberboard (MDF) or high-density fiberboard (HDF)) according to the present invention is shown. Detailed Implementation

[0030] Figure 1 A machine for manufacturing fiberboard (particularly medium-density fiberboard (MDF) or high-density fiberboard (HDF)) according to the prior art is shown, wherein fibrous material (particularly wood) is supplied from a digester 1 to a refiner 2 for fiber decomposition. The decomposed fibrous material forms a first mixture with steam in the refiner, and the first mixture is supplied from the refiner 2 to a dryer 4 via a blower pipe 3. It is also known from the prior art that the decomposed material (particularly wood) can be bonded together between the refiner 2 and the dryer 4 within a blower pipe (not shown).

[0031] Figure 2A machine for manufacturing fiberboard (particularly medium-density fiberboard (MDF) or high-density fiberboard (HDF)) according to the invention is shown. Fiber material (particularly wood, for example in the form of wood chips or sawdust) is also supplied from a digester 1 to a refiner 2 for fiber decomposition. The decomposed fiber material forms a first mixture with steam in the refiner, the first mixture exiting the refiner 2 at a first pressure and being supplied to a dryer 4 via a blow line 3. According to the invention, a post-fiber feed 5 is introduced into the blow line 3 after the refiner 2 and before the dryer 4 via a feed device 11. Advantageously, the feed 5 is performed closer to the dryer 4 than to the refiner 2, so that the feed 5 is performed at a pressure closer to the dryer 4 pressure than the refiner 2 pressure. Typically, the refiner pressure (i.e., the first pressure) is between 4 bar and 10 bar overpressure. Advantageously, the feeding device is positioned such that the feeding of post-added fibers into the blowing line is carried out at a pressure of up to 3 bar overpressure, preferably up to 2.0 bar overpressure, and particularly preferably up to 0.5 bar overpressure. The loosened fiber material can be bonded in a first bonding device 9, which is arranged upstream of the feed point 5 or between the refiner 2 and the feeding device 11.

[0032] Feeding device 11 is connected to refiner 2 and dryer 4 via blow line 3, wherein a second mixture comprising post-addition fibers and steam and / or air is supplied to feeding device 11 via second blow line 6. Advantageously, feeding 5 in feeding device 11 is performed according to the principle of jet pump, wherein a first mixture is supplied as a propellant to mixing chamber 7, and a second mixture is supplied as a suction medium to mixing chamber 7. The pressure of the second mixture can be increased upstream of feeding 5 by pressurizing device 8. The mixture comprising post-addition fibers and steam and / or air can be guided through pressurizing device 8, and the pressure of the mixture can be increased upstream of feeding 5, thereby performing mixing 18 of post-addition fibers and steam and / or air upstream of pressurizing device 8. Alternatively, steam and / or air can be guided through pressurizing device 8 only before the formation of the second mixture, wherein mixing 18 of post-addition fibers and steam and / or air is performed downstream of pressurizing device 8. Optionally, a second bonding device 10 is arranged on the second blowing line 6 for bonding the added fibers in the second mixture.

[0033] Figure 3A feeding device designed as a cyclone separator according to the present invention is shown. Here, the feeding device 11 is configured as a cyclone separator 12 and forms a jet pump. The cyclone separator 12 includes an inlet 13, an immersion pipe 14, a conical region 15, and an outlet 16. A blow line 3 is connected to or forms the immersion pipe 14, and a first mixture is supplied to the cyclone separator 12 through the blow line 3 or the immersion pipe 14. A second mixture is supplied to the cyclone separator 12 in the circumferential direction through the inlet 13. Here, the axis of the immersion pipe substantially defines the axial direction of the cyclone separator. The circumferential direction of the cyclone separator is considered to be concentric with the axial direction. The immersion pipe 14 extends into the conical region 15 of the cyclone separator 12, wherein a mixing chamber 7 is formed in the conical region 15 between the immersion pipe outlet 17 and the outlet 16. Corresponding to the jet pump, a first mixture comprising steam and fiber is supplied to the mixing chamber 7 as the propellant, while a second mixture comprising steam and / or air and subsequently added fiber is supplied to the mixing chamber 7 as the suction medium. Advantageously, the immersion tube outlet 17 can be positioned relative to the (cyclone separator) outlet 16, particularly along the axial direction of the cyclone separator or mixing chamber 7. This allows for control over the amount of the second mixture introduced into the mixing chamber 7.

[0034] Figure 4 Another machine for manufacturing fiberboard according to the present invention is shown, the machine being similar to... Figure 2 The machine illustrated differs in that it contains a separator 19. Here, the separator 19 is arranged within the blow line 3 between the refiner 2 and the feed device 11. The separator 19 is advantageously designed as a cyclone separator, wherein the first mixture is supplied to the cyclone separator through an inlet, and a portion of the steam of the first mixture is discharged through the impregnation tube of the cyclone separator. The separated steam, together with the added fibers, is supplied to the feed device 11 through the second blow line 6, wherein a portion of the separated steam can be guided through the pressurization device 8, supplying the steam to the added fibers upstream or downstream of the pressurization device 8. Optionally, the bonding of the second mixture can be performed before the feed 5. After the separator 19, the first mixture further contains fibers and a correspondingly reduced amount of steam, and is supplied to the feed device 11 through the blow line 3, wherein bonding 9 can optionally be performed between the separator 19 and the feed device 11. Steam can be utilized particularly efficiently using the separator 19.

[0035] This invention offers numerous advantages. It allows for efficient (due to good) mixing of fibers with added fibers. Because the energy or momentum of the first mixture is utilized in the blowing line, this invention allows for efficient (due to energy-advantageous) mixing.

[0036] List of reference numerals 1. Steamer 2. Pulping machine 3. Blowing Pipeline 4. Dryer 5. Feeding Area 6 Second blow line 7. Mixing Chamber 8. Pressure boosting device 9. Fiber bonding 10. Adhesive with added fibers 11 Feeding device 12 Cyclone Separator 13 Entrances 14 Immersion tubes 15 Conical Region 16 Exports 17 Immersion pipe outlet 18 Mixed 19. Separator

Claims

1. A method for manufacturing fiberboard, wherein, The lignocellulose fiber material is cooked in a digester (1) and then broken down into fibers in a refiner (2), wherein the fibers form a first mixture with steam, the first mixture exits from the refiner (2) at a first pressure and is supplied to a dryer (4) through a blow line (3), wherein after the refiner (2) and before entering the dryer (4), additional fibers are fed to the blow line (3), the additional fibers form a second mixture with steam and / or air and are supplied to a feed point (5) through a second blow line (6), characterized in that the feed is performed according to the principle of a jet pump, wherein the first mixture is supplied to a mixing chamber (7) as a propellant medium and the second mixture is supplied to the mixing chamber (7) as an intake medium.

2. The method according to claim 1, wherein, The fiberboard is medium-density fiberboard or high-density fiberboard.

3. The method according to claim 1, wherein, The lignocellulose fiber material is an annual plant or wood.

4. The method according to claim 3, wherein, The lignocellulose fiber material is in the form of wood chips or sawdust.

5. The method according to claim 1, wherein, The feed to the blow line (3) is carried out at a second pressure, and the second pressure is closer to the pressure of the dryer (4) than the first pressure.

6. The method according to claim 5, wherein, The first pressure is between 4 bar and 10 bar overpressure, and the second pressure is at most 3 bar overpressure.

7. The method according to claim 6, wherein, The second pressure is a maximum of 2.0 bar overpressure.

8. The method according to claim 7, wherein, The second pressure is a maximum of 0.5 bar overpressure.

9. The method according to any one of claims 1 to 8, wherein, The pressure of the second mixture in the second blow line (6) is increased by the pressurizing device (8) before the feed, or alternatively, the pressure of steam and / or air is increased by the pressurizing device (8) before the formation of the second mixture, and then the added fiber is mixed into the steam and / or air, and the second mixture is supplied to the feed point (5) through the second blow line (6).

10. The method according to any one of claims 1 to 8, wherein, The fibers are bonded after the refiner (2), and the subsequent fiber feeding is carried out after the fiber bonding.

11. The method according to claim 10, wherein, The added fibers are bonded before feeding.

12. The method according to any one of claims 1 to 8, wherein, After the refiner (2) and before the feed station (5), a portion of the steam is separated from the first mixture, and the added fibers are supplied to the feed station along with the portion of the steam.

13. An apparatus for manufacturing fiberboard, the apparatus comprising: A digester (1) for cooking lignocellulosic fiber materials, a pulper (2) for dissolving the fiber material into fibers, and a dryer (4) for drying the fibers, wherein the pulper (2) and the dryer (4) are connected by a blower pipe (3), and a feeding device (11) for feeding post-added fibers to the blower pipe (3) is arranged between the pulper (2) and the dryer (4), characterized in that the feeding device (11) is designed as a jet pump and includes a mixing chamber (7), one end of the feeding device (11) is connected to the pulper (2) through the blower pipe (3), and the other end is connected to a second blower pipe (6) for providing post-added fibers, wherein a first mixture comprising steam and fibers as a propellant can be supplied to the mixing chamber (7) through the blower pipe (3), and a second mixture comprising steam and / or air and post-added fibers as a suction medium can be supplied to the mixing chamber (7) through the second blower pipe (6).

14. The device according to claim 13, wherein, The fiberboard is medium-density fiberboard or high-density fiberboard.

15. The device according to claim 13, wherein, The lignocellulose fiber material is an annual plant or wood.

16. The device according to claim 15, wherein, The lignocellulose fiber material is in the form of wood chips or sawdust.

17. The device according to claim 13, wherein, The feeding device (11) is arranged in such a way that the feed into the blowing line (3) during operation is carried out under the pressure of the blowing line (3), and the pressure is closer to the pressure of the dryer (4) than the pressure of the refiner (2).

18. The device according to any one of claims 13 to 17, wherein, The feeding device (11) is designed as a cyclone separator (12), which includes an inlet (13), an immersion tube (14), a conical region (15), and an outlet (16). The blowing line (3) is connected to the immersion tube (14) or the blowing line (3) forms the immersion tube. The first mixture can be supplied to the feeding device (11) through the immersion tube (14), and the second mixture can be supplied to the feeding device (11) in the circumferential direction through the inlet (13). The immersion tube (14) extends to the conical region (15), and the mixing chamber (7) is formed in the conical region (15) between the immersion tube outlet (17) and the outlet (16).

19. The device according to claim 18, wherein, In order to control the amount of the second mixture that can be introduced into the mixing chamber (7), the immersion tube outlet (17) can be positioned relative to the outlet (16) of the cyclone separator.

20. The device according to claim 19, wherein, The immersion tube outlet (17) can be positioned relative to the outlet (16) of the cyclone separator along the axial direction of the mixing chamber (7).

21. The device according to any one of claims 13 to 17, wherein, A pressurizing device (8) for increasing the pressure of the second mixture is arranged on the second blowing line (6), or alternatively, the pressurizing device (8) is arranged upstream of the point where the fiber is recycled on the second blowing line (6).

22. The device according to any one of claims 13 to 17, wherein, A first bonding device (9) for bonding fibers is arranged in the blowing pipe (3) after the refiner (2) and before the feed device (11).

23. The device according to claim 22, wherein, The second bonding device (10) for bonding the added fibers is arranged upstream of the feeding device (11) in the second blowing pipe (6).

24. The device according to any one of claims 13 to 17, wherein, A separator (19) for separating a portion of the steam of the first mixture is arranged in the blowing line (3) between the refiner (2) and the feed device (11), wherein the separated steam portion can be supplied to the feed device (11) together with the added fibers.

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