INSTALLATION AND METHOD FOR PRODUCTION OF FIBER PANEL

Description

1 / 14 INSTALLATION AND METHOD FOR PRODUCTION OF FIBER PANEL

[001] The present invention relates to a method for producing a fiberboard, in particular MDF or HDF, wherein lignocellulosic material, for example, fibers from annual plants or wood, for example, in the form of wood chips or sawdust, is cooked in a digester, then defibrated into fibers in a refiner, wherein the fibers form a first mixture with steam, which emerges from the refiner at a first pressure, and is fed to a dryer by means of a blow line. The invention also relates to a plant for producing a fiberboard, in particular an MDF or HDF panel, comprising a digester for cooking lignocellulosic fiber material, for example, fibers from annual plants or wood, a refiner for defibrating the material into fibers, a dryer for drying the fibers, the refiner and the dryer being connected by means of a blow line.

[002] In the production of fiberboard panels, in particular fiberboard panels In MDF, the fiber is blown from the refiner along with steam as a first mixture at a first pressure in the drying process and fed through the blow line to the dryer, which is operated without pressure, i.e., atmospherically. In this way, the fibers, especially wood fibers, are sized in the blow line. Therefore, someone skilled in the art would recognize such an arrangement, for example, from EP3027806 A1, where a device for continuous steam discharge and a sizing device are disclosed between the refiner and the dryer.

[003] WO 2021176326 A1 discloses a method for the production of particleboard, MDF or HDF panels, comprising the recycling step of particleboard, MDF and / or HDF panel material, in which recycled wood chips and recycled wood fibers are Petition 870250091586, dated 07 / 10 / 2025, page 6 / 36 2 / 14 provided as starting material in a production process for particleboard, MDF panels or HDF panels - preferably in a dry production process.

[004] WO 2023031763 A1 discloses a method for producing a wood fiber panel, wherein recycled wood fiber panels are converted into recycled wood fibers; and wherein the recycled wood fibers are fed as starting material to a production line - preferably in a dry production process - for the production of wood fiber panels.

[005] DE 202016101394 U1 discloses a jet pump for loosening and separating wood fibers, wherein the wood fibers are fed into the jet pump by means of a suction nozzle; and the wood fibers encounter a propellant at the outlet of a drive nozzle disposed in the jet pump and are accelerated by that propellant.

[006] The goal is increasingly to add other fibers, for example, recycled fibers from MDF or HDF panels or alternative fibers, for example, from annual plants, to the manufacturing process. It makes sense to mix the other fibers with the existing fibers, especially fresh wood fibers, and feed the mixture into the conventional manufacturing process as an input material. Alternatively, it is appropriate to put the other fibers directly into the dryer. Both variants are based on the idea of ​​introducing the additional fibers into the manufacturing process without pressure, which is very easy to implement. On the other hand, direct addition to an area with excess pressure, for example, a refiner, is not recommended, since this is technically and energetically difficult and a high pressure difference has to be overcome.To make matters worse, pressure addition can lead to clumping of other fibers, or the addition may not be sufficiently pressure-tight, resulting in incorrect flow or even a plant shutdown. In general, these variants do not offer [a solution]. Petition 870250091586, dated 07 / 10 / 2025, page 7 / 36 3 / 14 good mix of fibers and other fibers.

[007] The object of the invention is a plant or method in which more fibers can be safely and efficiently introduced into the method or plant. A further object of the invention is to obtain good mixing of the fibers and additional fibers.

[008] According to the invention, this is achieved by the fact that after the refiner and before entering the dryer, more fibers are added to the blowing line. Additional fibers advantageously comprise chips and / or recycled fibers from recycled fiberboard, in particular particleboard, MDF and / or HDF panels, or alternative fibers, for example, from annual plants, and are ideally suited for the new production of a fiberboard, in particular an MDF or HDF panel. Additional fibers, therefore, also advantageously originate from a lignocellulosic fiber material. Surprisingly, it has been found that the introduction of additional fibers according to the invention allows for particularly good mixing of the fibers and the additional fibers, since high speeds and advantageous turbulence are formed in the blowing line. On the other hand, the introduction of additional fibers into the blowing line is advantageous because the additional fibers are not degraded, shortened, etc.between the feed and the dryer and, in particular, they are not cooked or ground.

[009] The method by which the feed is introduced into the blowing line at a second pressure, and the second pressure is closer to the dryer pressure than the first pressure, proves to be particularly advantageous. When feeding at a pressure closer to the dryer pressure, which is typically operated at atmospheric pressure, than to the first pressure, a large part of the first pressure has already been converted into kinetic energy, i.e., the flow of the first mixture of vapor and fibers occurs at a correspondingly high speed. On the other hand, feeding at such a second pressure is Petition 870250091586, dated 07 / 10 / 2025, page 8 / 36 4 / 14 advantageous, since the additional fibers – compared with the first pressure – only need to be brought to a correspondingly lower pressure level. Advantageously, the first pressure is particularly between 4 and 10 bar(g), the second pressure is particularly at a maximum of 3 bar(g), preferably a maximum of 2.0 bar(g) and particularly preferably a maximum of 0.5 bar(g).

[0010] According to the method of the invention, the additional fibers form a second mixture with steam and / or air and are fed into the feed through a second blow line. Feeding into the second mixture results in particularly effective mixing with the first mixture and, in particular, better mixing than if the additional fibers were fed in alone, for example, through a rotary valve.Routing the additional fibers in a separate second blow line also allows for the separate addition of chemicals, explicitly tailored to the needs of the additional fibers. At low second pressures, particularly down to a maximum of 0.2 bar(g), it may be technically sensible to introduce the second mixture as a mixture of additional fibers and air.

[0011] According to the invention, the second mixture is fed according to a jet pump principle, with the first mixture being fed to a mixing chamber as a motive medium and the second mixture being fed as a suction medium. Surprisingly, the momentum of the first mixture acting as a motive medium in a jet pump mixing chamber can be used to draw the second mixture into the mixing chamber as a suction medium. In this process, the first mixture of fibers and steam is fed to the mixing chamber via the blow line, and the second mixture of additional fibers and steam and / or air is fed via the second blow line. On the other hand, this achieves an energy-efficient feed and, on the other hand, the chamber of Petition 870250091586, dated 07 / 10 / 2025, page 9 / 36 The 5 / 14 jet pump mixing arrangement allows for excellent mixing of the first and second mixtures.

[0012] In a first, particularly advantageous embodiment of the method, the pressure of the second mixture is increased before it is fed through a pressure-increasing medium, so that the mixture of additional fibers and steam and / or air is fed into the pressure-increasing medium.

[0013] In an alternative, advantageous embodiment of the method, the pressure of the steam and / or air is increased by means of a pressure-increasing means before the second mixture is formed, then the other fibers are added to the steam and / or air and the second mixture is fed into the feed through the second blow line.

[0014] In both cases, the means for increasing pressure can be passive, i.e., a mixer for adding compressed air or pressurized steam, or active, i.e., a blower, fan, compressor, etc. The use of a blower or fan is recommended for a second mixing of additional fibers and air, such that blowers or fans allow only a small increase in pressure of 0.2 bar(g) at most in particular.

[0015] In both cases, additional fibers can also be added using a refiner, a fluffer, a rotary valve, a spindle, or similar.

[0016] Particularly advantageous is a method in which the fibers are subjected to sizing after the refiner and additional fibers are fed in after the fibers have been sized. This ensures sufficient residence time for the fibers between sizing and the dryer. To size the fibers, the dimension and air and / or steam are fed in particular to a two-substance nozzle, which achieves advantageous atomization of the dimension and efficient application. An equally advantageous method is one in which the fibers add Petition 870250091586, dated 07 / 10 / 2025, page 10 / 36 6 / 14 Fiber sizing is performed before feeding. This is advantageous if the quantity of the second blend increases relative to the quantity of the first blend. Sizing only the fibers of the first blend in the sense of "oversizing" is no longer effective or does not meet quality requirements. Fiber sizing before feeding can occur in the second blow line, for example, through the two-substance nozzle mentioned above, and allows controlled and specific sizing of the additional fibers in the second blend. Alternatively, sizing can also occur during the addition of the additional fibers to the second blow line, i.e., for example, in the refiner, fluffer, rotary valve, screw, or similar.

[0017] An equally advantageous method is one in which, after the refiner and before the feed, a portion of the steam is separated from the first mixture and the additional fibers are fed to the feed along with this portion of the steam. After this separation, the first mixture still contains the fibers and a smaller amount of steam is fed to the feed. The portion of steam separated from the blow line advantageously forms the second mixture along with the additional fibers and is also fed to the feed via the second blow line. This allows for particularly efficient use of steam.

[0018] The subject matter of the invention is also a plant for the production of a fiberboard, in particular an MDF or HDF panel, comprising a digester for cooking lignocellulosic fiber material, for example, fibers from annual plants or wood, for example, in the form of wood chips or sawdust, a refiner for defibrating the fiber material into fibers, a dryer for drying the fibers, the refiner and the dryer being connected by means of a blowing line. According to the invention, a feeding means is provided between the refiner and the dryer to feed Petition 870250091586, dated 07 / 10 / 2025, page 11 / 36 7 / 14 Addition of additional fibers to the blow line. As already explained in relation to the method according to the invention, this arrangement allows for efficient and particularly good mixing of the fibers and the additional fibers, so that degradation of the additional fibers is avoided.

[0019] According to an advantageous embodiment of the plant, the feeding medium is arranged so that, in operation, the feed to the blow line occurs at a blow line pressure, and the pressure is closer to the dryer pressure than to the refiner pressure. This allows the first mixture to be fed at a correspondingly high pressure, so that a comparatively small increase in pressure is sufficient to feed in the additional fibers.

[0020] In the embodiment of the plant according to the invention, the feeding medium is designed as a jet pump and comprises a mixing chamber, wherein the feeding medium is connected to the refiner by means of the blow line on one side and to a second blow line designed to provide additional lines on the other, and a first mixture of steam and fibers can be fed to the mixing chamber by means of the blow line as a motive medium and a second mixture of steam and / or air and additional fibers can be fed to the mixing chamber by means of the second blow line as a suction medium. In this way, the impulse of the first mixture can be used to draw the second mixture into the mixing chamber of the jet pump, so that an efficient and excellent mixture of the first and second mixtures is obtained. The mixture that later enters the dryer, comprising the fibers and the additional fibers, is virtually homogeneous.

[0021] Particularly advantageous is a plant in which the feeding medium is designed as a cyclone, the cyclone comprising an inlet, an immersion tube, a conical region and an outlet, the line Petition 870250091586, dated 07 / 10 / 2025, page 12 / 36 The 8 / 14 blow line is connected to the immersion tube or forms the latter, and the first mixture can be fed to the medium for feeding through the immersion tube. The second mixture can be fed through the inlet to the medium for feeding in a circumferential direction through the second blow line. The immersion tube extends into the conical region, and the mixing chamber is formed in the conical region between the outlet of one immersion tube and the outlet. Here, the immersion tube may include a nozzle or be designed as a nozzle in the area of ​​the immersion tube outlet in order to further accelerate the first mixture before it enters the mixing chamber. Designing the medium for feeding as a cyclone makes it easier to integrate the jet pump into the blow line.By introducing the second mixture through the inlet and in the convection direction of the cyclone, the second mixture is uniformly distributed around the circumference of the cyclone and, in particular, uniformly fed to the mixing area on the circumference, which in turn leads to very good mixing of the first and second mixtures in the mixing area. According to a particularly advantageous embodiment, the outlet of the immersion tube can be positioned relative to the outlet, in particular along an axial direction of the mixing chamber, respectively the cyclone, in order to regulate the amount of the second mixture that can be introduced into the mixing chamber. The axial positioning of the immersion tube outlet can be adjusted relative to the outlet or the conical area simply by moving the immersion tube or the blow line.In this way, the open ring cross-section between the conical area and the immersion tube can be effectively influenced or regulated and, consequently, the amount of secondary mixture introduced into the mixing chamber.

[0022] In a further embodiment of the plant, a means for increasing pressure is provided in the second blow line to increase the pressure of the second mixture or, alternatively, the means for Petition 870250091586, dated 07 / 10 / 2025, page 13 / 36 9 / 14 pressure increase is arranged upstream of an addition of additional fibers in the second blowing line. The means for pressure increase can be designed actively as a blower, fan, compressor, etc., or passively, i.e., as a mixer for adding compressed air or pressurized steam. The additional fibers are added using a refiner, a fluffer, a rotary valve, a screw, or similar.

[0023] A similarly advantageous embodiment of the plant is a first sizing device for sizing the fibers in the blow line, arranged downstream of the refiner and upstream of the feed medium, and optionally a second sizing device for sizing the added fibers is arranged in the second blow line upstream of the feed medium.

[0024] Particularly advantageous is a plant in which a separator for separating a portion of the vapor from the first mixture is arranged in the blowing line between the refiner and the feed medium, wherein the separated portion of vapor can be fed back to the feed medium along with the additional fibers. After the separator, the first mixture still contains the fibers and a smaller amount of vapor and is fed back to the feed medium through the blowing line. The portion of vapor separated from the blowing line advantageously forms the second mixture along with the additional fibers and is also fed back to the feed medium through the second blowing line.

[0025] The invention will now be described using the examples in the drawings.

[0026] Figure 1 shows a machine for producing a fiber panel, in particular an MDF or HDF panel, according to the state of the art.

[0027] Figure 2 shows a machine according to the invention. Petition 870250091586, dated 07 / 10 / 2025, page 14 / 36 10 / 14 for the production of a fiberboard panel, in particular an MDF or HDF panel.

[0028] Figure 3 shows a means for feeding according to the invention, which is designed as a cyclone.

[0029] Figure 4 shows an additional machine according to the invention for the production of a fiber panel, in particular an MDF or HDF panel.

[0030] Figure 1 shows a machine for producing a fiberboard, in particular an MDF or HDF panel, according to the state of the art, such that the fiberboard material, in particular wood, is fed from a digester 1 to a refiner 2 for defibration of the fiberboard material. The defibrated fiberboard material forms a first mixture with steam in the refiner, which is fed from the refiner 2 to a dryer 4 via the blowing line 3. It is also known from the prior art that the defibrated material, in particular wood, can be sized between the refiner 2 and the dryer 4 in the blowing line (not shown).

[0031] Figure 2 shows a machine according to the invention for producing a fiberboard panel, in particular an MDF or HDF panel. Fiber material, in particular wood, for example, in the form of wood chips or sawdust, is fed again from a digester 1 to a refiner 2 for defibration of the fiber material. The defibrated fiber material forms a first mixture with steam in the refiner, which is allowed to exit the refiner 2 with the first pressure and fed to a dryer 4 by means of a blowing line 3. According to the invention, after the refiner 2 and before entering the dryer 4, additional fibers are fed 5 into the blowing line 3 through a feeding means 11. Advantageously, the feeding 5 takes place closer to the dryer 4 than to the refiner 2, which means that the feeding 5 takes place in a Petition 870250091586, dated 07 / 10 / 2025, p. 15 / 36 11 / 14 pressure that is closer to the pressure of dryer 4 than to the pressure of refiner 2. Typically, the refiner pressure, i.e., the first pressure, is between 4 and 10 bar(g). It is advantageous to position the feed medium so that additional fibers are fed into the blow line at a maximum pressure of 3 bar(g), preferably a maximum of 2.0 bar(g) and particularly preferably a maximum of 0.5 bar(g). The defibrated material can be sized in a first sizing device 9, wherein the first sizing device 9 is arranged upstream of the feed 5 or between the refiner 2 and the feed medium 11.

[0032] The feed medium 11 is connected to the refiner 2 and the dryer 4 via the blow line 3, so that a second mixture of additional fibers and steam and / or air is fed to the feed medium 11 via a second blow line 6. Advantageously, the feeding 5 into the feed medium 11 occurs according to the principle of a jet pump, where the first mixture is fed to a mixing chamber 7 as a motive medium and the second mixture is fed as a suction medium. The pressure of the second mixture can be increased before feeding 5 via a pressure-increasing medium 8. It is possible to feed the mixture of additional fibers and steam and / or air via the pressure-increasing medium 8 and increase the pressure of the mixture upstream of the feed 5, so that the addition 18 of the additional fibers to the steam and / or air occurs upstream of the pressure-increasing medium 8.Alternatively, before the second mixture is formed, only steam and / or air can be passed through the pressure-increasing medium 8 and only then, that is, downstream of the pressure-increasing medium 8, more fibers 18 are added to the steam and / or air.

[0033] Optionally, a second sizing device 10 for sizing the additional fibers in the second Petition 870250091586, dated 07 / 10 / 2025, page 16 / 36 12 / 14 mixture is placed on the second blow line 6.

[0034] Figure 3 shows the feeding means according to the invention in the form of a cyclone. The feeding means 11 is designed as a cyclone 12 and forms a jet pump. The cyclone 12 comprises an inlet 13, an immersion tube 14, a conical section 15 and an outlet 16. The blow line 3 is connected to or forms the immersion tube 14 and the first mixture is fed to the cyclone 12 through the blow line 3 or the immersion tube 14. The second mixture is fed to the cyclone 12 in a circumferential direction through the inlet 13. This means that the axis of the immersion tube essentially defines the axial direction of the cyclone. The circumferential direction of the cyclone is concentric to the axial direction. The immersion tube 14 extends into the conical area 15 of the cyclone 12, so that a mixing chamber 7 is formed in the conical area 15 between the outlet of an immersion tube 17 and the outlet 16.According to a jet pump, the first mixture of steam and fibers is fed to the mixing chamber 7 as a motive medium and the second mixture of steam and / or air and additional fibers as a suction medium. Advantageously, the outlet of the immersion tube 17 can be positioned relative to the outlet 16, in particular along the axial direction of the cyclone or the mixing chamber 17. This allows the amount of the second mixture introduced into the mixing chamber 7 to be regulated.

[0035] Figure 4 shows an additional machine according to the invention for producing a fiber panel, which differs from the machine shown in Figure 2 by the presence of a separator 19. In this case, the separator 19 is arranged in the blowing line 3 between the refiner 2 and the feed medium 11. The separator 19 is advantageously designed as a cyclone, in which the first mixture is fed to the cyclone through an inlet and a portion of the vapor from the first mixture is discharged through an immersion tube from the cyclone. The separated part of Petition 870250091586, dated 07 / 10 / 2025, p. 17 / 36 13 / 14 steam is fed together with the additional fibers to the feed medium 11 through the second blow line 6, so that the separated part of the steam can be fed through a pressure-boosting medium 8 and the additional fibers are fed to the steam upstream 18 or downstream 18 of the pressure-boosting medium 8. Optionally, the second mixture can be sized before the feed 5. After the separator 19, the first mixture still comprises the fibers and a correspondingly reduced amount of value and is fed to the feed medium through the blow line 3, so that a sizing 9 can optionally occur between the separator 19 and the feed medium 11. The use of the separator 19 allows particularly efficient use of the steam.

[0036] The present invention offers several advantages. It allows for effective mixing – because it is good – of the fibers with the additional fibers. It also allows for efficient mixing – because it is energy-advantageous – since the energy content or momentum of the first mixture is used in the blowing line. Reference Numbers Digester Refiner Blow line Dryer Food Second line of blowing Mixing chamber A means of increasing pressure Fiber sizing Sizing of additional fibers Medium for feeding Cyclone Petition 870250091586, dated 07 / 10 / 2025, page 18 / 36 14 / 14 Prohibited Diving tube Conical section Exit Diving tube outlet Addition Separator Petition 870250091586, dated 07 / 10 / 2025, page 19 / 36

Claims

1 / 4 CLAIMS 1. Method for producing a fiberboard, in particular an MDF or HDF board, wherein lignocellulosic fiber material, for example, fibers from annual plants or wood, for example, in the form of wood chips or sawdust, is cooked in a digester (1) and then defibrated into fibers in a refiner (2), the fibers forming a first mixture with steam, which emerges from the refiner (2) at a first pressure and is fed to the dryer (4) through a blow line (3), additional fibers being fed (5) to the blow line (3) after the refiner (2) and before entering the dryer (4), the additional fibers forming a second mixture with steam and / or air and are fed to the feed (5) through a second blow line (6), characterized in that the feed (5) is based on the principle of a jet pump,the first mixture being fed to a mixing chamber (7) as a motive medium and the second mixture being fed as a suction medium.

2. Method according to claim 1, characterized in that the feed (5) in the blowing line (3) occurs at a second pressure, and the second pressure is closer to the dryer pressure (4) than to the first pressure, and in that the first pressure is in particular between 4 and 10 bar(g), the second pressure is in particular at most 3 bar(g), preferably at most 2.0 bar(g) and particularly preferably at most 0.5 bar(g).

3. Method according to any one of claims 1 or 2, characterized in that the pressure of the second mixture in the second blow line (6) is increased by means of a pressure-increasing means (8) before the feed (5) or, alternatively, the pressure of the steam and / or air is increased by means of a pressure-increasing means (8) before the second mixture is formed, after Petition 870250091586, dated 07 / 10 / 2025, page 20 / 36 2 / 4 that additional fibers are added to the steam and / or air and the second mixture is fed to the feed (5) through the second blow line (6).

4. Method according to any one of claims 1 to 3, characterized in that the fibers are subjected to a sizing (9) after the refiner (2) and the feeding (5) of additional fibers occurs after the sizing (9) of the fibers, wherein optionally a sizing (10) of additional fibers occurs before the feeding (5).

5. Method according to any one of claims 1 to 4, characterized in that after the refiner (2) and before the feed (5) a portion of the steam is separated from the first mixture and the additional fibers are fed to the feed along with that portion of the steam.

6. Plant for the production of a fiberboard, in particular an MDF or HDF panel, characterized in that it comprises a digester (1) for cooking lignocellulosic fiber material, for example, fibers from annual plants or wood, for example, in the form of wood chips or sawdust, a refiner (2) for defibration of the fiber material into fibers, a dryer (4) for drying the fibers, wherein the refiner (2) and the dryer (4) are connected via a blowing line (3), wherein a feeding medium (11) for feeding (5) additional fibers into the blowing line (3) is disposed between the refiner (2) and the dryer (4), wherein the feeding medium (11) is designed as a jet pump and comprises a mixing chamber (7), the feeding medium (11) is connected on one side to the refiner (2) via the blowing line (3) and on the other side to a second blowing line (6) designed to provide the additional fibers,wherein a first mixture of steam and fibers may be fed to the mixing chamber (7) via the blow line (3) as a motive medium and a second mixture of steam and / or air and additional fibers may be fed via the second blow line (6) as a suction medium.

7. Plant according to claim 6, characterized in that the feeding medium (11) is arranged so that, in operation, the feeding (5) into the blow line (3) occurs at a blow line pressure (3), and the pressure is closer to the dryer pressure (4) than to the refiner pressure (2).

8. Plant according to any one of claims 6 or 7, characterized in that the feed medium (11) is designed as a cyclone (12), the cyclone (12) comprises an inlet (13), an immersion tube (14), a conical region (15) and an outlet (16), the blow line (3) is connected to or forms the immersion tube (14) and the first mixture can be fed to the feed medium (11) through the immersion tube (14), the second mixture can be fed to the feed medium (11) in a 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 outlet of an immersion tube (17) and the outlet (16).

9. Plant according to claim 8, characterized in that the outlet of the immersion tube (17) can be positioned in relation to the outlet (16), in particular along an axial direction of the mixing chamber (7), in order to regulate the amount of the second mixture that can be introduced into the mixing chamber (7).

10. Plant according to any one of claims 6 to 9, characterized in that a means for increasing the pressure (8) of the second mixture is disposed in the second blow line (6) or alternatively the means for increasing the pressure (8) is disposed upstream of a mixture of the recycled fibers in the second blow line (6).

11. Plant according to any one of claims 6 to 10, characterized in that a first sizing device (9) for sizing the fibers in the blow line (3) is arranged downstream of the refiner (2) and upstream of the feed medium (11) and optionally a second sizing device (10) for sizing the additional fibers is arranged in the second blow line (6) upstream of the feed medium (11).

12. Plant according to any one of claims 6 to 11, characterized in that a separator (19) for separating a portion of the vapor from the first mixture is disposed in the blow line (3) between the refiner (2) and the feed medium (11), wherein the separated portion of the vapor can be fed to the feed medium together with the added fibers. Petition 870250091586, dated 07 / 10 / 2025, p. 23 / 36

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