EP1480797A1

EP1480797A1 - Device for the production of a non-woven

Info

Publication number: EP1480797A1
Application number: EP03706585A
Authority: EP
Inventors: Friedrich Schröder
Original assignee: Binos Technologies & Co KG GmbH
Current assignee: BINOS GmbH
Priority date: 2002-03-02
Filing date: 2003-02-27
Publication date: 2004-12-01
Anticipated expiration: 2023-02-27
Also published as: ATE488344T1; EP1480797B1; AU2003208770A1; DE50313267D1; DE20203427U1; WO2003074243A1

Abstract

The invention relates to devices for the production of a non-woven (2) consisting of fibrous particles, comprising a pneumatic fractionating device (8) and a forming substrate (24) on which a fractionated flow of particles (9) can be arranged in such a way that relatively small particles are disposed in a lower and upper outer layer and relatively large particles are disposed in a middle layer (31) in said non-woven (2). A group of rollers (20) is arranged in a device on a first end section (10) of the fractionated particle flow containing the smallest particles and a conveyor belt (18) circulating around said group of rollers is arranged in a higher position. The fraction mixture can be fed by the conveyor belt to the group of rollers embodied in the form of a homogenizing unit which successively spreads partial flows (25,26,27) onto the forming substrate. In another device, one group of rollers (43) is provided on an end section of the particle flow containing the largest particles, in addition to an inclined screening device (40) which is arranged downstream from the fractionating device (8) and which conducts the larger particles to the group of rollers(43) acting as a homogenizing unit.

Description

DESCRIPTION

Device for producing a fleece

12. The invention relates to devices according to the preamble of claims 1 and 12 respectively.

In a known device according to the preamble of claim 1 (EP 0 800 901 A1), the starting mixture is subjected to a mechanical pre-dissolution and then pneumatically separated by an air flow directed transversely to the direction of fall. Part of the pneumatically separated material flow falls on a unit for controllable mechanical dissolution of this part and for its scattering in such a way that the material particle thickness in the fleece increases continuously. This unit has a roller chair with several rollers that can be rotated about their horizontal axis. Every second roll can be raised or lowered to influence the final separation. The unit can be moved horizontally by the pneumatically separated material flow. Each roller can be regulated in its speed and direction of rotation. This device is complex and complex to drive and coordinate all drivable elements.

DE 198 46 106 A1 describes a spreading station for evenly depositing a spreadable material with a pneumatic fractionation device and a roller group. The roller group is not assigned to a specific section of the fractionated litter material, but extends over the entire extent of the fractionated litter material in the direction of the mold base. The roller group also serves to mix the spreading material. Because of the arrangement of the roller group, however, no distinction is made according to the different size of the particles in different fractions of the scattering material; rather, all particles of the fractionated scattering material are equally affected by the roller group. influenced. In addition, a roller group arranged in this way is not very effective in terms of mixing the scattering material.

From DE 28 47 109 A1 a device is known per se in which two register groups blow sifter air in opposite directions through the falling starting mixture. The pneumatically fractionated particles are sprinkled directly onto the fleece carrier or the resulting fleece. This leads to an undesirable concentration of fine particles in the two outer layers, which are later lost when the sheets made from the fleece are sanded.

From WO 01/66324 A1 it is known per se to produce successive fraction mixtures of the particles with increasing average size from the starting mixture. Each fraction mixture is fed to a homogenization unit designed as a roller group, where it is divided into homogenized partial streams. These partial flows are successively scattered onto the mold base or onto the nonwoven that is created. The construction effort is comparatively high here.

DE 40 21 939 A1 discloses a device according to the type of the preamble of claim 12. In the area of the ejection parabolas of the pneumatic fractionation device, the device has a ball catching device which extends from the area perpendicularly under the ejection of the fibrous particles in the direction of the ejection parabolas and ends before the end of the area of the ejection parabolas. The ball catching device serves to catch balls that should have formed in the raw material to be scattered, even if they follow the wind forces, and to discharge them against the direction of the wind. However, the ball safety device allows chips to pass through. The ball catching device can have a disk sieve with a plurality of disk rollers with intermeshing disks which are driven in the same direction and whose intermeshing disk allows chips to pass through. Furthermore, the device can be provided with screens which are arranged within the discharge parabolas in order to catch balls and to guide them to the disk screen. The ball catching device is thus designed so that it only has one Has an influence on the balls, which are undesirable and therefore have to be sorted out, but has no influence on the chips which are intended for the production of the fleece.

DE 20 49 721 A describes a device for sprinkling wood chips in which a vibrating sieve is provided downstream of a pneumatic fractionation device perpendicular to a mold base. The sieve serves to catch the light particles with a particularly large surface area, which may be driven to the opposite outer ends of a distribution chamber, and to guide them onto the fleece at locations between the surfaces of the press-ready fleece, where they are of quality do not adversely affect the plate.

DE 42 12 001 A1 also describes a device for scattering fibrous particles, in which a sieve is arranged downstream of a pneumatic fractionation device. This sieve forms a flying chip catcher and has an overall orientation perpendicular to a mold base. The screen is wavy in cross section, in particular zigzag folded. As a result, a large screen area is achieved and, furthermore, it is achieved that, based on the folding, an upper screen area for the air flow is essentially freely and freely passable.

DE 44 39 653 A1 discloses a scattering device for glued particles, in which a collecting device for coarse material is provided at a transport end of a roller group.

The invention has for its object to improve the shaping of the fleece.

This object is solved by the features of claim 1. Glue is preferably used as a binder for the particles, in particular chips, in a manner known per se. The fleece is then fed to a press and pressed into a plate-shaped workpiece. On this workpiece the cover layers have a comparatively high density because of the relatively small particles arranged therein. These top layers are usually sanded smooth afterwards. In this grinding process, according to the invention, only comparatively small proportions of the finest particles are removed. This is achieved in that the first end section of the fractionated particle stream, which also contains the smallest particles, is caught by the conveyor belt and mixed and homogenized on the first roller group. This creates a fraction mixture of the smallest, but also larger particles. The homogenized fraction mixture is sprinkled in several partial streams onto the mold base or the resulting fleece. It is particularly advantageous that the disadvantages of so-called dust spots or glue spots on the fleece are avoided. Such stains have hitherto been caused by the fact that lumps of dust or glue, which form somewhere in the device over time, suddenly fall down in an uncontrolled manner and reach the fleece. Such stains not only lead to optically disruptive areas on the finished product, but also to a reduction in strength right up to scrap. According to the invention, such lumps of dust or glue cannot reach the surface of the fleece. If such lumps should reach the first roller group of the homogenization device, they are mixed there together with the fraction mixture and homogenized in such a way that they can no longer cause any impairment. According to the invention, the homogenized fraction mixture thus forms the outer layers of the fleece. In the aforementioned grinding process on the finished pressed plate, only the outermost part of the cover layers is removed. The particular advantage of the procedure according to the invention is that the ground surface of the plate contains significantly more fines than in the prior art. This results in a desirably higher density on the ground surface and less roughness on the outer surface of the plate created by the grinding.

According to claim 2, large particles entrained by the classifying air and in particular so-called flying chips can be intercepted in a simple and effective manner. Flying chips are chips that have a ratio of have a moderately large surface area and are nevertheless quite light, so they are easily carried away by the visible air.

Due to the features of claim 3, the relatively large particles are homogenized and scattered onto the fleece in several homogenized partial streams. In this way, a favorable, controlled particle distribution is obtained even in the middle area of the fleece. According to claim 4, it can also be provided to provide gaps of different sizes between the rollers of the second roller group.

According to claim 5 can be avoided in a simple manner that coarse material gets into the fleece.

The features of claim 6 are particularly favorable in terms of drive technology. In this case, the fraction mixture can be applied to an end region of the first roller group. The homogenization then takes place over the entire length of the first roller group in the direction of the relative movement. In particular, it can be provided that all rollers of the second roller group rotate in such a direction of rotation that the impinging particles are transported in the direction of the screening device. This enables particularly effective mixing to be achieved.

According to claim 7, the homogenization can be influenced favorably.

According to claim 8, all particles that have passed through the screen are collected by the conveyor belt and later homogenized by the first roller group.

By the features of claim 9, however, a horizontal distance between the transport and a back of the screen is created. A central region of the fractionated particle stream which has penetrated through the sieve falls through this distance. This central area has a continuously changing particle size in the direction of the relative movement on. This creates a transition layer between the homogenized cover layer and the possibly also homogenized middle layer of the nonwoven. This transition layer with its continuously changing particle size can create a technologically particularly favorable transition from the top layer to the middle layer.

According to claim 10, the thickness of the aforementioned transition layer can be adjusted via the horizontal distance.

Due to the features of claim 11, the horizontal distance is structurally particularly easy to set.

The object is further achieved by the features of claim 12. Glue is preferably used as the binder. After the fleece is formed, it is fed to a press and pressed into a plate-shaped workpiece. The particles reach a mold support under the action of a pneumatic fractionation device. There is a relative movement between the fractionation device and the mold base. That is, the mold base either moves relative to the fractionation device or vice versa. Relatively small particles are arranged in a lower cover layer and an upper cover layer of the nonwoven to be produced. A sieve device with at least one sieve inclined with respect to the horizontal is arranged downstream of the particle trajectories of the fractionation device in such a way that relatively large particles can be captured from the fractionated particle stream. These trapped particles are used to make the fleece. As the finest and smaller particles pass through the screening device and into the lower cover layer, the trapped particles are placed on a roller group by the inclination of the screening device. This roller group is arranged in such a way that particles from an end section of the fractional particle stream containing the largest particles hit the roller group. The largest particles are the least widely blown by the fractionator. The roller group serves as a homogenization unit. The rollers of the roller group are arranged parallel to one another and transversely to a relative movement in terms of height between the mold base and the pneumatic fractionation device. There is a gap between the individual adjacent rolls of the roll group, which is uniform in the longitudinal direction of the rolls and each forms a partial flow of the homogenized particles. The rollers of the roller group rotate in the same direction of rotation and each scatter a particle stream of the homogenized particles on the mold base.

By means of the device according to the invention, a homogeneous middle layer is scattered on the lower cover layer, which consists of the fine particles that have passed through the sieve device. The middle layer consists of the particles trapped by the sieve device, which are larger than the particles forming the lower cover layer, and the still larger particles, which have not reached the sieve device through the fractionation device.

As a result of the device according to the invention, the middle layer, as described above, consists of particles of different sizes mixed and thus homogenized. This is very advantageous for the following reasons: First, existing air spaces between larger particles are filled with smaller particles. Since it is known that larger particles, when glued together with smaller particles, receive considerably less glue application than the finer particles, the finer particles with their higher glue content form glue bridges to the larger, less glued particles. This leads to a more closed middle layer, which in particular has higher transverse tensile strengths, and an improvement in the panel properties. Because if the roller group were not present, the particles in the scattered fleece would increase in size from the lower cover layer to the middle of the middle layer, ie the largest particles would be deposited in the middle of the middle layer. Without the screening device, the increase in the particles from the lower cover layer to the middle of the middle layer would be seamless. Because of the different glue application the weakest zone of the plate produced would be in the middle of the middle layer, since it would contain the least amount of glue and air spaces between the larger particles would not be filled with finer particles. Because of the air spaces, the middle class would make an "open" visual impression. Such a plate would in particular have low transverse tensile strengths, but it would also have poor nail and screw retention properties and poorer properties with regard to millability, grooves and tongues etc. These negative properties could only be achieved by using a higher amount of glue and / or a higher specific weight the overall plate can be improved.

On the other hand, according to the invention, the specific weight of plates and the amount of glue can be reduced due to the mixing of differently sized particles in the middle layer, the strength properties, in particular the transverse tensile strength, being retained. In this way, considerable savings in production costs can be achieved.

The rollers preferably have a direction of rotation such that the particles are transported in the direction of the screening device, that is to say the coarser particles are transported to the particles coming from the screening device onto the roller group. This enables particularly effective mixing to be achieved. The direction of rotation of the rollers can also be such that the smaller particles are transported to the larger particles.

The gaps between the individual adjacent rolls of the roll group can be the same. However, the gaps between the individual rolls can also be of different sizes, in particular the gaps within groups of rolls of the roll group can be the same, but the groups can have gaps of different sizes. The gaps can also increase or decrease in the transport direction. In this case, an increase or decrease in the gap size can also be provided in groups. At the end of the roller group to which the particles are transported, a coarse material collecting device can be provided which has not fallen through the gaps of the roller group.

These and other features and advantages of the invention are explained in more detail below on the basis of the exemplary embodiments illustrated in the drawings. It shows

1 shows a schematic longitudinal section through a first embodiment of the device according to the invention,

2 shows another embodiment of a detail from FIG. 1,

3 shows a schematic longitudinal section through a further embodiment of the invention,

Fig. 4 is a schematic longitudinal section through yet another embodiment of the invention and

Fig. 5 is a schematic longitudinal section through yet another embodiment of the invention.

1 shows a device 1 for the continuous production of a nonwoven 2 from fibrous particles provided with a binder, in particular chips, of different sizes. An output mixture 3 of the particles arrives in a manner known per se on a conveyor belt 4 from a metering hopper (not shown) to a discharge point 5. The output mixture 3 dropped there initially falls vertically downwards and is then acted upon by sifting air 6, which comes from a register in the horizontal direction 7 of a pneumatic fractionation device 8 exits.

The sight air 6 has the consequence that the starting mixture is fractionated into a fractional particle stream 9. The finest particles of the partial stream 9 in a first end section 10 and the coarsest particles in a second end section 11 of the fractionated particle stream.

This fractionation of the starting mixture 3 takes place in a viewing chamber 12, the housing 13 of which is only partially indicated. A wall 14 of the housing 13 facing away from the register 7 is provided with fine openings 15 through which the exhaust air 16 can leave the viewing chamber 12. The visual exhaust air 16 is cleaned in a manner known per se from residual dusts and preferably recirculated to the register 7.

The first end section 10 of the fractionated particle stream 9 is caught by an upper run of a conveyor belt 18 which runs in the direction of an arrow 17. The first end section 10 collected in this way is dropped onto a first roller group 20 according to an arrow 19 at the right end of the conveyor belt 18 in FIG. 1. Rollers 21 of the first roller group 20 are arranged identically and with longitudinal axes parallel to one another and oriented transversely to a relative movement 22 and in this case can be driven in the same direction as the arrows 23 in the same direction. The relative movement 22 takes place between a mold base 24 and the device 1. In the exemplary embodiment shown, the mold base 24 is designed in the form of a band and can be driven to generate the relative movement 22. In this case, the device 1 itself is arranged stationary. Alternatively, the device 1 can be moved and the mold base 24 can be arranged in a stationary manner during the spreading process.

The first end section 10 forms a fraction mixture which is fed onto the first roller group 20 in the direction of the arrow 19. The first roller group 20 ensures intensive mixing and homogenization of the fraction mixture. Between adjacent rolls 21 of the first roll group 20 there is a gap 28 of equal size, each forming a partial flow 25 to 27 of the homogenized fraction mixture.

The partial flows 25 to 27 are successively scattered in the manner schematically indicated in FIG. 1 and form a lower one on the mold base 24 Cover layer 29 with a thickness of 30. The lower cover layer 29 is thus formed by three homogenized layers from the partial streams 25 to 27 which are essentially identical to one another.

A lower half 31 of a middle layer is subsequently sprinkled on this lower cover layer 29. This takes place with the second end section 11 of the fractionated particle stream 9. The second end section 11 extends in FIG. 1 to the right up to the conveyor belt 18 and has a decreasing particle size from left to right. Correspondingly, the lower half 31 of the middle layer in FIG. 1 has a particle size increasing from bottom to top and a thickness 32.

In a manner known per se, the upper half of the fleece 2 is subsequently scattered in the reverse order by a further device (not shown), which is arranged in mirror image with respect to FIG. 1, in accordance with the device 1. Thus, first the upper half and subsequently an upper cover layer corresponding to the lower cover layer 29 is applied to the lower half 31 of the middle layer. The fleece 2 thus finished is then fed in a manner known per se to a preferably continuous press for the production of plates.

Fig. 2 shows a way to change the effective length of the conveyor belt 18. For this purpose, a right deflection roller 33 is arranged in a stationary manner. A left deflection roller 34, however, is horizontally adjustable in the directions of a double arrow 35. 2, the left deflection roller 34 is drawn in the end position in which the minimum effective length of the conveyor belt 18 results. To increase the effective length of the conveyor belt 18, an adjusting roller 36 is moved to the left in FIG. 2, while the conveyor belt 18 continues to run over a stationary deflection roller 39. The effective length of the conveyor belt 18 can be adjusted continuously. Correspondingly, the first end section 10 of the fractionated particle stream 9 caught by the conveyor belt 18 becomes larger or smaller and the thickness 30 of the lower cover layer 29 becomes larger or smaller. In all drawing figures, the same parts are provided with the same reference numbers.

In FIG. 3, the conveyor belt 18 is preceded by a screening device 40 which is inclined with respect to the horizontal. As shown, the sieve device 40 can have only one sieve, or alternatively also several sieves. In this case, the conveyor belt 18 is brought up to a rear side 41 of the screening device 40. Thus, all of the particles of the fractional particle stream 9 which pass through the sieving device 40 are caught by the conveyor belt 18 and used in the manner already described to scatter the lower cover layer 29. On the other hand, relatively large particles 42 are intercepted from the fractionated particle stream 9 by the left-hand side of the screening device 40 in FIG. 3 and are fed together with the second end section 11 of the fractionated particle stream 9 onto a second roller group 43. This second roller group 43 is also designed as a homogenization unit, by means of which the charged particles are homogenized with regard to the particle size. Between adjacent rollers 44 of the second roller group 43 there is a gap 48 of equal size, each forming a partial stream 45 to 47. The partial streams 45 to 47 are essentially identical and homogenized with one another and are successively scattered to form the lower half 31 of the middle layer. Finally, in the exemplary embodiment according to FIG. 3, there is also a homogenized size distribution of the particles in the middle layer.

At a transport end of the second roller group 43, a collecting device 49 for coarse material 50 is provided, which the gaps 48 of the second roller group 43 could not pass. In this case, a transport screw 51 transports the coarse material 50 out of the collecting device 49.

The embodiment according to FIG. 4 represents a modification of the device 1 according to FIG. 3. The difference lies in the fact that in FIG. 4 the conveyor belt 18 is at a horizontal distance 52 from the rear side 41 of the screen device. device 40 is arranged. The size of the horizontal distance 52 can be adjustable, for example by the features according to FIG. 2.

Due to the horizontal distance 52, not all of the particles that have passed through the sieving device 40 fall onto the conveyor belt 18. Rather, the area of these particles on the left in FIG. 4 between the conveyor belt 18 and the rear side 41 of the sieve 40 passes directly onto the lower cover layer 29 scattered. This creates a transition layer 53 with a thickness 54 and a scattering length 55 on the lower cover layer 29. In the transition layer 53, the size of the particles increases continuously from bottom to top. In this way, a technologically favorable transition from the homogenized, relatively small particle size in the lower cover layer 29 and the homogenized, relatively large particle size in the lower half 31 of the middle layer is created.

5 shows a further device 1 for the continuous production of a fleece 2 from fibrous particles provided with a binder, in particular chips of different sizes. An output mixture 3 of the particles arrives in a manner known per se on a conveyor belt (not shown) from a metering bunker (not shown) to a discharge point 5. The output mixture 3 dropped there initially falls vertically downward and is then acted upon by classifying air 6, which comes from a horizontal direction Register 7 of a pneumatic fractionation device 8 emerges.

The sight air 6 has the consequence that the starting mixture is fractionated into a fractional particle stream 9. The finest particles of the particle stream 9 can be found in a first end section 10 and the coarsest particles in a second end section 11 of the fractionated particle stream.

This fractionation of the starting mixture 3 takes place in a viewing chamber 12, the housing 13 of which is only partially indicated. A wall 14 of the housing 13 facing away from the register 7 is provided with fine openings 15, through which viewing air 16 leaves the viewing chamber 12 can. The visual exhaust air 16 is cleaned in a manner known per se from residual dusts and preferably recirculated to the register 7.

The pneumatic fractionation device 8 is followed by a sieving device 40 which is inclined with respect to the horizontal. As shown, the sieve device 40 can have only one sieve, or alternatively also several sieves. All particles of the fractionated particle stream 9 passing through the screening device 40 are deposited by gravity on a mold base 24, which moves relative to the pneumatic fractionation device 8, and form a lower cover layer 29 with a thickness 30. In the exemplary embodiment shown, the mold base 24 is in the form of a band trained and driven to generate the relative movement 22. Alternatively, the mold base 24 can also be arranged in a stationary manner during the spreading process, while the other parts of the device 1 move relative to the mold base 24.

The size of the particles in the lower cover layer 29 increases with increasing distance from the mold base 24.

A lower half 31 of a homogeneous middle layer is subsequently sprinkled onto the lower cover layer 29. This is done, as explained below, with the second end section 11 of the fractionated particle stream 9 and the particles 42 collected by the sieve device 40. These particles 42 are finer relative to the particles of the second end section 11, but coarser relative to the particles of the first end section 10. The second end section 11 extends in FIG. 5 to the right up to the screening device 40 and has a particle size that decreases from left to right.

The relatively large particles 42 are intercepted from the fractionated particle stream 9 by the screening device 40 and, together with the second end section 11 of the fractionated particle stream, are fed onto a roller group 43. The roller group 43 is designed as a homogenization unit, by means of which the particles fed in with regard to the partial size can be mixed thoroughly and homogenized. The gaps 48 between adjacent rollers 44 of the roller group 43 are the same size and each form a partial flow 45 to 47. The rollers 44 can rotate in such a way that the impinging particles are transported in the direction of the screening device 40, that is to say the larger particles to the smaller particles be transported. The direction of rotation can also be reversed. Due to the homogenizing effect of the rollers 44, the particle streams 45 to 47 are essentially the same and homogenized. The particle streams 45 to 47 are successively scattered to form the lower half 31 of the middle layer. The lower half 31 has a thickness 32.

It can also be provided that the gaps have different sizes, individually or in groups.

In a manner known per se, the upper half of the fleece 2 is subsequently scattered in the reverse order by a further device (not shown), which is arranged in mirror image with respect to FIG. 5, corresponding to the device 1. Thus, first the upper half and subsequently an upper cover layer corresponding to the lower cover layer 29 is applied to the lower half 31 of the middle layer. The fleece 2 thus finished is then fed in a manner known per se to a preferably continuous press for the production of plates.

Claims

EXPECTATIONS

Device (1) for the continuous or discontinuous production of a fleece (2) from fibrous particles provided with a binder, in particular chips of different sizes,

with at least one pneumatic fractionation device (8) for the fractionation of an initial mixture (3) of the particles into a fractionated one

Particle stream (9),

with a mold base (24) onto which the fractionated particle stream (9) can be applied by means of a relative movement (22) between the mold base (24) and the device (1) in such a way that in the finished fleece (2) in a lower one

Cover layer (29) and relatively small particles in an upper cover layer and relatively large particles in a middle layer (31),

and with at least one each a section (10; 1 1) of the fractionated

Particle stream (9) associated roller group (20; 43),

wherein the rollers (21; 44) of each roller group (20; 43) are arranged with longitudinal axes parallel to one another and oriented transversely to the relative movement (22) and can be driven in rotation,

characterized in that a first roller group (20) is arranged on a first end section (10) of the fractured particle stream (9) which also contains the smallest particles,

that, higher than the first roller group (20), a circulating conveyor belt (18) collecting the first end section (10) of the fractionated particle stream (9) as a fraction mixture is arranged, that the fraction mixture can be applied to the first roller group (20) by the conveyor belt (18),

that the first roller group (20) is designed as a homogenization unit, by means of which the fraction mixture can be homogenized with regard to the particle size,

that between adjacent rolls (21) of the first roll group (20) there is a gap (28) of equal size, each forming a partial flow (25, 26, 27) of the homogenized fraction mixture,

and that the partial streams (25, 26, 27) can be scattered in succession onto the mold base (24) or onto the resulting fleece (2).

2. Device according to claim 1,

characterized in that the conveyor belt (18) is preceded by a screening device (40) inclined with respect to the horizontal and having at least one screen,

and that relatively large particles (42) can be captured from the fractionated particle stream (9) by the screening device (40).

3. Device according to claim 2,

characterized in that the captured relatively large particles (42) can be applied to a second roller group (43) together with a second end section (11) of the fractionated particle stream (9) which also contains the largest particles,

that the second roller group (43) is designed as a homogenization unit, by means of which the applied particles can be homogenized with regard to the particle size, that between adjacent rollers (44) of the second roller group (43) there is an equally large gap (48) forming a partial stream (45, 46, 47) of the homogenized particles,

and that the partial streams (45, 46, 47) can be successively scattered onto the resulting fleece (2).

4. The device according to claim 2,

that the second roller group (43) is designed as a homogenization unit, by means of which the applied particles can be homogenized with regard to the particle size,

that between adjacent rollers (44) of the second roller group (43) there are gaps (48) of different sizes, each forming a partial stream (45, 46, 47) of the homogenized particles,

and that the partial streams (45, 46, 47) one after the other can be scattered onto the resulting fleece (2).

5. The device according to claim 3 or 4,

characterized in that a collecting device (49) for a coarse material (50) is provided at a transport end of the second roller group (43) which has not passed through the gaps (48) of the second roller group (43).

6. Device according to one of claims 1 to 5,

characterized in that all rollers (21; 44) of each roller group (20; 43) rotate in the same direction of rotation.

7. Device according to one of claims 1 to 5,

characterized in that the rollers of each roller group (20; 43) rotate in different directions of rotation.

8. Device according to one of claims 2 to 7,

characterized in that the conveyor belt (18) is brought up to a rear side (41) of the screening device (40).

9. Device according to one of claims 2 to 7,

characterized in that the conveyor belt (18) is arranged at a horizontal distance (52) from a rear side (41) of the screening device (40).

10. The device according to claim 9,

characterized in that the size of the horizontal distance (52) is adjustable.

11. The device according to one of claims 1 to 10,

characterized in that an effective length of the conveyor belt (18) can be changed.

12. Device (1) for the continuous or discontinuous production of a nonwoven (2) from fibrous particles provided with a binder, in particular chips of different sizes, with at least one pneumatic fractionation device (8) for fractionating an initial mixture (3) of the particles into a fractionated particle stream (9),

with a mold base (24) onto which the fractionated particle stream (9) can be applied by means of a relative movement (22) between the mold base (24) and the pneumatic fractionation device (8) such that in the finished fleece (2) in a lower cover layer ( 29) and relatively small particles are arranged in an upper cover layer and relatively large particles are arranged in a middle layer (31),

with at least one roller group (43) assigned to a section (10; 11) of the fractionated particle stream (9),

wherein the rollers (44) of each roller group (43) are arranged with longitudinal axes parallel to one another and oriented transversely to the relative movement (22) and can be driven in rotation,

and with a sieve device (40) inclined with respect to the horizontal, which has at least one sieve and is connected downstream of the pneumatic fractionation device (8),

characterized in that

the screening device (40) is designed to capture relatively large particles (42) from the fractionated particle stream (9) intended for producing the fleece (2),

that the intercepted relatively large, to manufacture the fleece

(2) provided particles (42) together with an end section (11) of the fractionated particle stream (9) also containing the largest particles can be applied to a roller group (43), that the roller group (43) is designed as a homogenization unit, by means of which the applied particles can be homogenized with regard to the particle size,

that between adjacent rollers (44) of the roller group (43) there is a gap (48) which is uniform in the longitudinal direction of the rollers (44) and forms a partial stream (45, 46, 47) of the homogenized particles,

that the rollers (44) of the roller group (43) rotate in the same direction of rotation

13. The device according to claims 12,

characterized in that the gaps (48) between adjacent rollers (44) are of different sizes.

14. The apparatus according to claim 13,

characterized in that the gaps (48) between adjacent rollers (44) are of different sizes individually or in groups.