Device for air classification of classifiable material, and method for operating such a device

Abstract

A device (1) and method for air classification, having a housing (10) for an air flow (2) which preferably acts counter to gravitational force, and having an air supply (12) arranged on the housing (10), a material inlet (17) for the material (7) to be classified and at least a first outlet (13) for a first fraction (3) and a second outlet (14) for a second fraction (4), and an orifice plate (6), as flow resistance, which is arranged between the air supply (12) and the material inlet (17) over the length (L) and width (W) of the housing (10) and which has a plurality of openings (9) for predetermined distribution and / or orientation of the air flow (2), wherein the plane of the orifice plate (6) is preferably arranged perpendicularly or at an angle to the air flow (2), and adjusting means (24) are arranged (1638) for changing the orientation of the openings (9) and / or for changing the opening cross section (19) of individual, all or grouped openings (9).

Description

[0001] Device for air screening of classifiable material

[0002] AND METHOD FOR OPERATING SUCH A DEVICE

[0003] The invention relates to a device for air classification of classifiable material according to the preamble of patent claim 1.

[0004] The invention further relates to a method for operating a device for air classification of classifiable material according to the preamble of patent claim 15.

[0005] Such devices are used industrially to classify solids into different fractions according to defined criteria, such as density, inertia, and size. Usually, in addition to similar materials,

[0006] Mixtures are classified, for example, in recycling, to obtain pure fractions. Classification processes and corresponding equipment are demanding and maintenance-intensive systems in 24 / 7 operation or in large-scale industrial applications.

[0007] In the production of material boards based on lignocellulose-containing materials, foreign substances such as silicates, sand, and dust are often found. However, metals, plastics, and other foreign substances are also found in waste wood recycling. These foreign substances must be separated before the cleaned material can be used in large-scale industrial plants for the production of material boards, plastic boards, or mixed boards. A riser sifter is typically used here, in which an air stream is passed through a substantially vertical shaft against the force of gravity. Heavier material is not carried by the air stream and falls downwards, whereas lighter material is discharged at the top of the shaft. The material to be sifted is usually fed in from the side of the air stream.In addition to the basic physical principle, a zigzag air classifier is typically used in the technological field of air classification for lignocellulosic materials, resulting in improved separation efficiency. This air classifier features zigzag channels that guide the air flow, allowing for repeated redirection of the air flow and the materials to be classified.

[0008] EP 1 874 489 B1 discloses a multi-stage classification or cleaning process for separating foreign bodies, minerals, plastic, glass, and the like. In a second stage, an air-classifying classification device as described above is used, on which the invention is based. A perforated plate is arranged between the material feed and the air supply for the air flow, through which the (defective) fraction of heavier material (glass, minerals, metal) can generally fall. This perforated plate generally serves as a flow brake or to even out the incoming air, acting as a flow baffle in the housing of the classification device. The perforated plate can be arranged at an angle. Materials too large for the openings can thus slide down sideways and enter another discharge outlet for a separate fraction.

[0009] Such a device has generally proven itself for classifying materials, but exhibits weaknesses in 24 / 7 industrial application and ease of maintenance. Particularly with challenging input materials, such as waste wood, prolonged or continuous operation is problematic or even impossible. Furthermore, if the aperture is arranged at a sufficiently angled and thus self-cleaning position, the separation efficiency of the air classifier suffers significantly because, due to the angled position, the aperture is not fluidically perpendicular to the main flow direction. In fluid terms, each opening acts as a nozzle, which is thus directed at an angle against a wall of the housing.

[0010] In addition, it has been shown that larger foreign bodies tend to get caught or stuck in the openings and thus do not slide out of the air sifter along the slope, but cause further build-up of foreign material on the aperture or the perforated plate.

[0011] The object of the present invention is to create a device for air classification, or rather, an air classifier, and a method for operating such a device that avoids the above-mentioned disadvantages regarding maintenance compared to the prior art. It should also be possible to achieve not only improved ease of maintenance but also improved separation accuracy despite a structurally simpler air classifier. In addition, an expanded object should be to be able to adjust the device depending on the material to be classified, its properties, or its quantity per unit of time.

[0012] The invention relates to a device for air classification of classifiable material, comprising a housing for an air flow preferably acting against gravity, with an air supply arranged on the housing, a material inlet for the material to be classified and at least one first outlet for a first fraction and a second outlet for a second fraction, and a baffle arranged between the air supply and the material inlet over the length and width of the housing as a flow resistance with a plurality of openings for the predetermined distribution and / or orientation of the air flow, wherein the plane of the baffle is preferably provided perpendicular or at an angle to the air flow.The solution to the problem for the device is that, in order to adjust the air flow and / or to clean the aperture, adjusting means for changing the orientation of the openings and / or adjusting means for changing the opening cross-section of individual, all or grouped openings are arranged.

[0013] The solution to the problem for a method is that in order to adjust the air flow and / or to clean the aperture, preferably downstream, the orientation of the aperture openings and / or the opening cross-section of individual, all or grouped openings is changed.

[0014] Preferably, several segments are arranged to form the aperture. These segments should be arranged so that they can move or be moved differently relative to one another.

[0015] The actuators for moving the segments could be mechanically, pneumatically, hydraulically and / or electrically driven.

[0016] Particularly preferably, the segment is arranged substantially entirely across the length or width of the housing and, together with the other segments, forms the flow-related baffle. In addition, the baffle can serve not only as a flow brake or to even out or direct the air flow, but also as a sieve for fractionation.

[0017] In this constellation, the first fraction A would be a good fraction, the second fraction B would be oversized and the third fraction would be heavy goods such as metals, stones, sand or the like.

[0018] In principle, such an air classifier should produce at least two fractions: a good fraction for further use and a separated fraction that is either further processed, fractionated again, or disposed of. In such an air classifier, the good fraction A is transported upwards through the air classifier and used for its intended purpose, whereas heavier particles or particles not belonging to the good fraction are not sufficiently carried by the air flow and fall downwards against the air flow. Depending on the design of the baffle and the air classifier, the material that does not rise can be fractionated again through the baffle.For example, heavy material can fall or trickle through the openings of the baffle as one fraction and larger but non-rising material can remain on the baffle as another fraction and be discharged, for example, through an inclined baffle by means of vibration at the side of the housing.

[0019] Depending on the material feed used, material may become trapped in the openings and cannot pass through or be removed to the side. This material accumulates to a greater or lesser extent during operation, depending on the degree of contamination, and is usually removed from the screen during maintenance. These irregularly occurring additional flow resistances increase the effort required to create proper airflow, reduce the cleaning performance of the air classifier partially or in large quantities over a large area, and lead to a poorer separation efficiency and thus lower efficiency.

[0020] The inventive solution changes or shifts the orientation of the aperture openings relative to the airflow, resulting in a cleaning effect. The aperture is cleaned, for example, by the foreign material sliding sideways, the segments emerging from the airflow, or by changing their angle relative to the airflow. In the latter case, the aperture openings change their position or orientation, possibly until foreign bodies fall out of the openings. The regular airflow in the housing or in the inspection area is used as a reference or guide for the orientation of the openings. However, the cleaning effect can also be achieved or performed without airflow or using a stronger airflow.

[0021] Preferably, the individual segments are pivotable about an axis. The segments can be arranged so that they pivot laterally about an axis or, preferably, so that they rotate about a central axis. By pivoting the segments, foreign bodies resting on the segments or material caught in the openings can fall downwards and are ultimately discharged (see Figures 2 to 4).

[0022] Depending on the application and requirements, the axes can be arranged stationary or movable within, on, or relative to the housing. For example, the axes can be arranged reversibly or continuously along a guide and / or through a conveyor. In a preferred embodiment, the segments can leave the air flow or enter a separate area within the housing for the air flow, where they can change the position of the segments and be cleaned accordingly (see Figure 6).

[0023] Alternatively or cumulatively, the segments in the lower run or return run of the continuously rotating conveyor can be aligned parallel or orthogonal to the air flow. With a parallel alignment, the air flow would not be further impeded, and classified material could easily pass (only) through the upper run and be discharged from the air classifier below, see Figure 6.

[0024] In a preferred embodiment, the segments can be arranged so that they abut one another to form the aperture. A continuous rotation would be conceivable here, in which the aperture opens and closes again after a 180° rotation of the segments, see Figures 2 or 3. The segments can also overlap at least partially or rest on the axes of adjacent segments. In this case, a reversing movement would be preferable.

[0025] Alternatively or cumulatively, the segments can be designed to be flat, cross-shaped, or star-shaped in cross-section or perpendicular to their axis. In such an application, it would not be necessary to perform a full 180° rotation to close the aperture again. Accordingly, smaller angles of rotation may be necessary, see Figure 4.

[0026] In a particularly preferred embodiment, if multiple segments are arranged on an axis, first and second segments with different openings can be arranged. This advantageously allows the aperture to be designed to be adjustable in terms of its permeability to the air flow and also to the material to be classified, and to be adjusted depending on the operating mode without having to manually replace the aperture. At the same time, the cleaning effect can still be achieved by pivoting / rotating the aperture segments.

[0027] In an alternative or even cumulative embodiment, the baffle or the segments of the baffle can be designed in at least two layers in the direction of the air flow, wherein each layer has identical and / or different openings and the layers are arranged so as to be adjustable or adjustable relative to one another to adjust the effective opening cross-section, see Figure 5. There are few limits to the possibilities here; for example, the entire baffle can consist of two layers, the openings of which can be moved relative to one another to influence the air flow accordingly or to adjust the screening effect of both the air sifter and the baffle. In addition, the baffle can be cleaned by enlarging the opening, as oversized or caught foreign bodies can fall through.

[0028] In addition, it can be advantageous to shift the layers along the width of the housing to adjust the opening cross-section relative to the flow brake, and along the length for a cleaning effect. For the cleaning effect, for example, the opening cross-section could be disproportionately larger.

[0029] It is also possible to arrange several segments with different setting effects or opening patterns in order to further vary the aperture setting options.

[0030] Especially when there are several segments, only some segments can be adjusted with regard to the opening cross-section, or the adjusting devices can be used in groups or the openings can be moved or swivelled in groups.

[0031] The same effect can also be used advantageously on the layers of individual segments, whereby advantageously and in accordance with the invention, the segmented arrangement makes it possible to set different flow velocities in the length and / or width of the air classifier or the flow cross-section of the air flow or to compensate for flow differences due to the design or material.

[0032] In addition to an equalization of the air flow through and after the aperture, it is advisable in a further preferred embodiment to design the supply of the sifting air into the housing laterally through the housing or at least to introduce it at an angle from below into the housing, so that the material passing through the aperture and sifted or the fraction can fall freely downwards and be discharged from the housing by a discharge device, for example a screw drive or a rotary valve.

[0033] In this regard, it may be advantageous to install air baffles in the area of ​​the airflow deflection, i.e., at the level of the air supply and upstream of the material inlet, preferably upstream of the baffle. These support the deflection and even out the airflow, which is usually deflected around an imaginary axis.

[0034] In the particular embodiment of the invention, the air supply is arranged at an angle to the air flow in the housing. The air baffles serve to optimally deflect the air flow into the vertical direction. These are preferably arranged at a distance and / or in a cascade along the height of the air supply.

[0035] Particularly preferably, the guide vanes are designed and arranged as a geometrically and flow-optimized row of guide vanes for low-loss flow deflection and / or to prevent flow separation. It is preferably provided that the guide vanes completely cover the axial extent of the rotation axis and preferably absorb only a portion of the air flow oriented orthogonally thereto, or leave the remaining areas of the air flow to further guide vanes arranged behind them or in a cascade.

[0036] Preferably, the air baffles would be arranged in the direction of flow on the outlet side of the baffle at equal distances from the baffle across the length or width of the housing. In this distance range without baffles, the baffle can, if necessary, exert its equalizing effect across the length and width of the housing. In an alternative embodiment, the air baffles can be arranged radially spaced along a deflection axis and / or in a cascade across the cross-section of the air flow. The deflection effect can be further optimized by the spaced and / or stepped arrangement along a radius.

[0037] Alternatively or cumulatively to the air baffles, further guide plates can be arranged on the radially outer region, preferably at the end of the deflection region or in the vertical region of the housing after the deflection.

[0038] Preferably, the guide plates are arranged at a distance from the air baffle to the baffle, which differs on the outlet side, near or in front of the baffle to direct the air flow. The guide plates are preferably spaced apart from the deflecting air baffles and most preferably arranged in areas with a greater distance between the air baffles and the baffle, see Figure 7.

[0039] Furthermore, the following advantageous embodiments or explanations would be beneficial for understanding the invention:

[0040] A zigzag guide for the air flow can be arranged downstream of the material inlet in the direction of the air flow. This serves to improve the separation efficiency of the air separation. Larger or overly heavy particles are physically slowed down by contact with the plates of the zigzag guide and are not discharged as the good fraction at the top.

[0041] Preferably, the axis for rotating or pivoting the segments is arranged across the entire length or width of the housing. However, it should at least be located in the area of ​​the airflow. The axis does not have to be mechanically continuous, but can also be implemented with a one- or two-sided suspension.

[0042] From a process engineering perspective, it may be useful for the orifice plate to switch to a cleaning mode at specified intervals during operation or during a break in operation, and for the segments to be rotated, tilted, or shifted. This enlarges the openings or directly or as a result changes their orientation relative to a normal flow direction, particularly to remove foreign matter that may become trapped in the openings.

[0043] The rotation or tilting preferably takes place in a stationary manner along an axis. The pivot or rotation angle for the segments depends on their design and arrangement. For example, with a star-shaped segment structure with four segments, pivoting by 90° may be sufficient, but other rotation or pivot angles are conceivable, such as 120° with three radially arranged segments, or a plurality of the necessary pivot angles to adjust a usable aperture again. For example, rotation by 360° is also possible. After the cleaning rotation, the segment returns to its original position. Reversing pivoting movements are also conceivable, such as 180° in one direction and 180° back again.

[0044] In addition, it may be useful to provide safety elements or corresponding sensors that provide feedback to the personnel in the event of blockage of the segments or the actuating means to initiate maintenance of the device.

[0045] Advantageously, it is now possible to clean the aperture without having to provide excessively angular bevels or vibrating elements, which in turn reduce the cleaning performance, increase the environmental impact through noise or wear.

[0046] In a particularly preferred embodiment of the classifier, the material fed in is divided by the air classifier into a first fraction A, a second fraction B and a third fraction C, wherein above the baffle, the first fraction A is discharged upwards by the air flow and the third fraction C is discharged laterally, whereas the second fraction B passes through the baffle as a sieve passage against the air flow. In this case, it is particularly provided that the baffle can be cleaned by preferably briefly changing the position or orientation of the openings or by enlarging the opening cross-section of the openings, by preferably briefly carrying out this change. Particularly preferably, an automated control system is provided for this purpose, which at predetermined intervals or on the basis of a controlled system, based on measuring devices for or during the discharge of the fractions orThe necessary change is caused or activated by the dynamic pressure of the air flow in front of and / or after the aperture.

[0047] The present invention is particularly intended for the use of the device or classifier in which the aperture or a corresponding screen is used to separate a separate fraction. Apertures or screens that are arranged sufficiently obliquely relative to gravity and / or the air flow exhibit a kind of self-cleaning effect or will not have a significant sieve passage, thus no second fraction B.

[0048] The cleaning action can preferably be carried out during a sifter shutdown in the sense of a lack of feeding and / or air flow. In this case, suspended solids that are not currently discharged as the first fraction A but remain in the sifter during the air flow can be separated as a further second fraction B', separated and discharged through the baffle plate due to the lack of further feeding of material, when the air flow is deactivated and this material comes to rest on the baffle plate. In addition, when feeding is stopped, the oversized material that has accumulated and / or become entangled on the baffle plate can also be advantageously discharged as a separate fraction B* if the second fraction B has left the sifter during regular operation.

[0049] The invention preferably provides, among other things, that the openings and / or their opening cross-section are arranged or used in a first operating position for sifting the fractions and that in a second operating position, preferably briefly, the possibility for the sieve fall-through or sieve passage is expanded or increased by the change in the aperture.

[0050] It is particularly preferred that the segments rotate to such an extent that the openings are no longer arranged or are arranged exactly opposite to each other in the air flow.

[0051] In a further cumulative or alternative application, preferably for a device for classifying at least three fractions, a baffle is provided which consists of several segments, wherein adjacent segments are preferably closed to one another at their joints and the air flow can only pass through the segments or the openings in the segments. Alternatively, it can also be provided that the openings at the joints or between the segments approximately correspond to the openings in the segments, wherein the effect of the change in position of the segments would be the same for the openings at the joints. The term "joint between the segments" is understood to mean the adjacent or closed arrangement between two segments, preferably in the operating position.

[0052] In a further particularly preferred embodiment, it should be noted that the segments are provided as perforated sheets or with a plurality of openings suitable for the air flow, wherein a single opening is preferably not arranged over the entire width W but rather a plurality of openings are arranged on the segment over the width W and also along the length L.

[0053] Alternatively or additionally, the aperture can be segmented longitudinally and / or transversely. The segments would then be arranged longitudinally and / or transversely, i.e., along the length L or width W of the intended aperture.

[0054] Depending on the device design, the aperture can be in an operating position in which the openings or segments remain stationary in an operating position, preferably for a given material over a longer period of time, and the aperture's function for the air flow and / or for the second fraction B is fulfilled. In a second cleaning position, the cleaning effect is achieved and the aperture or segments are cleaned. The cleaning position can be static, for example, remaining in a different position for a short time, but can also be dynamic, for example, in which one or more movements or one or more rotations are performed for cleaning.

[0055] This sifter or device will be used primarily for biomass or woody materials. This can be particularly useful for sifting woody materials prior to the production of particleboard, fiberboard (MDF, HDF), or OSB (oriented strand board). In this example, the material in the feedstock would then consist of shredded fresh wood, possibly with bark, minerals, or foreign bodies (nails, staples, etc.), or of waste wood with contaminants such as paint layers, foils, plastics, metals, etc.). However, annual plants or other biomass, with varying degrees of woodiness or even no woodiness at all, can also be sifted using this device or sifter.

[0056] Preferably, the second fraction is intended for the separation of minerals, silicates, or the like. The screen, preferably designed as a segmented perforated plate, should have openings large enough to minimize the loss of material or the passage through the screen, while minimizing the loss of usable material, such as wood.

[0057] In a further preferred embodiment, the size of the openings or the sieve mesh width can be adjusted differently along the length of the baffle. For example, it is advantageous if the holes or the openings of the baffle become continuously or gradually larger along the material flow (from the material inlet to the discharge of the third fraction C). This has the advantage that initially only fine foreign bodies or minerals are separated through the small openings and the lightest and / or smallest part of the first fraction A is carried away from the material inlet by the air flow, while further along the length L larger openings are arranged through which larger mineral particles can be separated without an excessive amount of material from the first fraction A passing through the sieve into the third fraction C.

[0058] Alternatively or cumulatively, different hole patterns can also be selected, for example elongated holes.

[0059] The advantage is reduced effort or even elimination of the subsequent cleaning of the third fraction C (screen overflow of the orifice plate). In addition, the material loss of the first fraction A or the third fraction C, which would otherwise be partially discharged as off-cuts in the fraction, is reduced.

[0060] With regard to the openings and their position and orientation, it is preferably specified that the openings or the aperture are set or arranged in a predetermined working position in order to enable the predetermined effect as an aperture for the air flow but also as a sieve for the material not transported by the air flow. The openings or the opening cross-section are therefore preferably arranged in one plane. Preferably, for cleaning, these openings are adjusted and / or moved with regard to their orientation, preferably with the segments containing the openings. For cleaning, these openings or segments therefore preferably assume a second cleaning position or are guided along a movement kinematics or a cleaning movement.

[0061] Further advantageous measures and embodiments of the subject matter of the invention emerge from the subclaims and the following description with the schematic drawing.

[0062] They show:

[0063] Figure 1 is a schematic side view of an air sifting device according to the invention with a cross-sectional view of the housing below, perpendicular to the plane of the drawing, Figure 2 is the structure of a segmented aperture with three different positions of the segments relative to the axes shown one below the other,

[0064] Figure 3 shows the structure of an alternative segmentation with segments arranged on both sides of the rotation axis with different positions and an exemplary ejection of a foreign body from a segment by its rotation, Figure 4 shows a further preferred embodiment of a star-shaped or cross-shaped segment and, if applicable, a preferred embodiment with different openings,

[0065] Figure 5 shows a segment in layered construction with an adjustable opening cross-section,

[0066] Figure 6 is a schematic representation of a diaphragm formed from a plurality of movable segments along an endlessly rotating conveyor and

[0067] Figure 7 is a schematic representation of a deflection of the air supply for the air flow in the housing with air baffles and guide plates.

[0068] The drawing shows, in Figure 1, a schematic side view of a device 1 for air classification of a material 18, which is fed to the device 1 via a material inlet 17. The device 1 preferably has a rectangular housing with a width W and a length L, in which a vertical air flow 2 fractionates the material 18 entering the housing 10 into various fractions. It is provided that the good material, as the first fraction 3, is transported upwards with the air flow 2 to the discharge 13 of fraction A and from there is fed for further use in a manufacturing process.

[0069] For example, in the case of woody materials, this could be the production of particleboard, fiberboard (MDF, HDF), or OSB (oriented strand board). In this example, material 18 in material input 17 would then consist of shredded fresh wood, possibly with bark, minerals, or foreign bodies (nails, staples, etc.), or of waste wood with contaminants such as paint layers, foils, plastics, metals, etc.).

[0070] Minerals or heavy foreign bodies such as nails, screws are removed by the

[0071] Air flow is not transported upwards and falls below the

[0072] Material inlet 17 is directed to a baffle 6, which has openings 9 for the passage of the air flow 2 and the second fraction 4. Through the air inlet 12 arranged laterally on the housing 10, a sealed conveyor screw can be arranged in the lower area and discharge the second fraction 4 via the discharge 14. Fraction B, consisting predominantly of heavy material, is generally disposed of or recycled.

[0073] In a preferred and optional embodiment, a third fraction 5 can be generated, which generally consists of reusable oversized pieces, for example, pieces of wood that are too thick or too heavy. This third fraction 5 moves along the baffle 6 away from the material inlet 17 towards the discharge 15. This can be achieved by the air flow 2, by an inclined arrangement of the baffle 6 as in Figure 1, or by other conveying means. To deflect the air arriving orthogonally to the sifting air flow 2 via the air supply 12, air baffles 11 are arranged, which are blade-shaped across the width W. The air baffles are arranged in a cascade and spaced apart from one another, and their total number represents the height of the incoming air in a stepped manner.Preferably, the downstream ends of the air baffles 11 are spaced apart from the aperture 6 in order not to reduce the effect of the flow brake through the openings 9 of the aperture 6.

[0074] To improve the classifying effect of the device 1, a zigzag guide 16 for the air flow 2, formed by corresponding sheets, can be arranged in the upper area of ​​the housing.

[0075] Figure 2 schematically illustrates the structure of a segmented diaphragm 6. The segments 8 are hinged to axes 7, which form a pivot axis for the segments. Actuating means 24, mechanical, electrical, or pneumatic, are suitable for pivoting the axes 7 with the attached segments 180° counterclockwise. The second line shows the initial pivoting process, and the third line shows the completed pivoting process.

[0076] Figure 3 shows an alternative structure for the segmentation of the aperture 6 with segments 8 arranged on either side of the (rotational) axis 7 or with one segment 8 and a centrally arranged axis 7. A foreign body 20, for example a screw or a nail, is arranged in the left segment 8 and cannot fall through the opening 9. The cleaning function is represented in the second line by a staggered position of the segment 8 from left to right. After activation of the adjusting means 24, the segment begins to rotate counterclockwise; in the middle, the segment 8 is vertical, and shortly before completing a 180° rotation, the foreign body 20 falls downwards.

[0077] Figure 4 shows another preferred embodiment of a star-shaped or cross-shaped segment. In this embodiment, the cross-shaped segment 8 has smaller openings 9 than the segment 8', which is arranged offset at a 90° angle. In addition to the possible adjustment of a different effect of the orifice plate 6 with respect to a flow brake or as a sieve, the cleaning effect is also achieved by rotating the cross-shaped segment.

[0078] Figure 5 shows a further preferred embodiment of a diaphragm 6, with a segment 8 in a layered construction and thus with an adjustable opening cross-section 19. Both layers 21, 22 have openings 9, which can be of different sizes if necessary. By shifting the layers 21, 22 relative to one another using appropriate adjusting means, the opening cross-section 19 can be enlarged or reduced. In addition to adjusting the function of the diaphragm 6, it is also possible to carry out cleaning when larger heavy particles cannot fall through the diaphragm 6. In this case, the layers 21, 22 are shifted relative to one another such that the largest possible opening cross-section 19 can be set.The displacement of the layers 21, 22 relative to one another can be carried out by displacing one layer, but it would also be conceivable to displace a layer along the width W of the housing in order to adjust the opening cross-section and to displace a layer along the length W or vice versa in order to carry out a cleaning function, wherein in the latter displacement the opening cross-section could be disproportionately enlarged in order to increase the cleaning effect.

[0079] According to Figure 6, a schematic representation shows the formation of a baffle 6 from a plurality of movable segments 8 along a continuously rotating conveyor 23. The segments are moved clockwise along the length L of the housing 10 by an adjusting means 24 and hang in the lower run 25 on the axes 7 parallel to the air flow 2. As a result of the conveying, the segments 8 are deflected towards the upper run and lie flat against one another, in steps or on corresponding holders, forming a baffle 6 in the upper run. For example, the axes 7 can serve as abutments. The continuously rotating conveyor 23 is preferably formed by two externally running chains to which the segments 8 are articulated via the axes 7. Foreign bodies 20 on the baffle 20 fall into a discharge when they transfer to the lower run 25 due to a folding effect caused by gravity.In contrast to the embodiment shown in Figure 1, the foreign bodies 20 do not fall through downwards, but remain in a different fraction. The removal of the other fraction is significantly improved with this embodiment. Because the segments "hang" in the lower run, only one baffle 6 is in operation. However, with appropriate guides, the segments 8 could also be aligned orthogonally to the air flow 2 in the lower run, so that the classifier air passes through the flow brake twice to even out the air flow 2.

[0080] Figure 7 is a schematic representation of a further advantageous embodiment of a deflection of the secure air downstream of the air supply 12 for the air flow 2 in the housing 10 with air baffles 11 and guide plates 26. An imaginary deflection axis 27 with a radius has been drawn schematically, which is intended to represent the deflection area or the deflection radius. The air baffles 11 are spaced apart in the height of the air flow, offset, and essentially arranged in a cascade, as in Figure 1, in order to cover and redirect the height of the horizontal air flow. The air baffles 11 preferably extend across the entire width W of the housing. With a substantially horizontal arrangement of a panel 6, the distance between the panel 6 and the air baffles 11 may be too large.In order to avoid uncontrollable air flows, it may be necessary to arrange guide plates 26 between the air baffles 11 and the cover 6 in the area of ​​the larger distance 1638.

[0081] Reference symbol list 1638:

[0082] 1 device

[0083] 2 Air flow (sighted)

[0084] 3 Fraction (A)

[0085] 4 Fraction (B)

[0086] 5 Fraction (C)

[0087] 6 aperture

[0088] 7 Axis

[0089] 8 segments

[0090] 9 Opening

[0091] 10 housings

[0092] 11 air deflectors

[0093] 12 Air supply

[0094] 13 Discharge (Fraction A)

[0095] 14 Discharge (Fraction B)

[0096] 15 Discharge (Fraction C)

[0097] 16 Zigzag guide

[0098] 17 Material entry

[0099] 18 Materials

[0100] 19 Opening cross-section

[0101] 20 foreign bodies

[0102] 21 shift (first)

[0103] 22 shift (second)

[0104] 23 Conveyor system

[0105] 24 setting agents

[0106] 25 lower strand

[0107] 26 guide plates

[0108] 27 Deflection axis

[0109] L length of 10

[0110] W width of 10

Claims

Patent claims 1. Device for air classification of classifiable material, comprising a housing (10) for an air flow (2) preferably acting against gravity, with an air supply (12) arranged on the housing (10), a material inlet (17) for the material (18) to be classified, and at least one first outlet (13) for a first fraction (3) and a second outlet (14) for a second fraction (4), and a baffle (6) arranged between the air supply (12) and the material inlet (17) over the length (L) and width (W) of the housing (10) as a flow resistance, with a plurality of openings (9) for the predetermined distribution and / or orientation of the air flow (2), wherein the plane of the baffle (6) is preferably arranged perpendicularly or at an angle to the air flow (2), characterized in that adjusting means (24) for changing the orientation of the openings (9) and / or Adjusting means (24) are arranged for changing the opening cross-section (19) of individual, all or grouped openings (9).

2. Device according to claim 1, characterized in that a plurality of segments (8) are arranged to form the aperture (6), wherein preferably one segment (8) extends substantially completely over the length (L) or width (W) of the housing (10).

3. Device according to claim 2, characterized in that the individual segments (8) are arranged pivotably on an axis (7), preferably rotatably on a central axis (7).

4. Device according to claim 3, characterized in that the axes (7) are arranged stationary or movable, preferably reversing or endlessly circulating along a guide and / or a conveyor device (23).

5. Device according to claim 4, characterized in that in the lower run (25) or in the return run of the endlessly circulating conveyor device (23) the segments (8) are aligned parallel or orthogonal to the air flow (2).

6. Device according to at least one of claims 2 to 5, characterized in that the segments (8) for forming the diaphragm (6) are arranged abutting, at least partially overlapping or resting on the axes (7) of adjacent segments (8).

7. Device according to at least one of the preceding claims, characterized in that the segments (8) are flat, cross-shaped or star-shaped in cross section or perpendicular to their axis (7).

8. Device according to claim 7, characterized in that, in the case of a plurality of segments (8), first and second segments (8) with mutually different openings (9) are arranged on an axis (7).

9. Device according to at least one of the preceding claims, characterized in that the diaphragm (6) or the segments (8) of the diaphragm (6) are arranged in at least two layers in the direction of the air flow (2). are designed, wherein each layer (21, 22) has identical and / or different openings (9) and the layers (21, 22) are arranged to be adjustable or adjustable relative to one another in order to adjust the effective opening cross-section (19).

10. Device according to at least one of the preceding claims, characterized in that air baffles (11) are arranged at the level of the air supply (12) and in the flow direction in front of the material inlet (17), preferably in the flow direction in front of the aperture (6).

11. Device according to claim 10, characterized in that the air supply (12) is arranged at an angle to the air flow (2) in the housing (10) and the air baffles (11) for deflecting the air flow (2) into the vertical, preferably spaced apart and / or cascading over the height of the air supply (12).

12. Device according to claim 10 or 11, characterized in that the guide plates (11) are arranged as a geometrically and flow-optimized row of guide vanes, preferably with a blade-shaped contour, for low-loss flow deflection and / or for preventing flow separation.

13. Device according to one of claims 10 to 12, characterized in that the air baffles (11) are arranged in the flow direction on the outlet side of the aperture (6) over the length (L) or width (W) of the housing at the same distances from the aperture (6).

14. Device according to one of claims 10 to 12, characterized in that the air guide plates (11) are arranged radially on a deflection axis (27) and / or over the cross section of the air flow are arranged in a cascade, wherein, preferably with a different distance between the air baffles (11) and the baffle (6) on the outlet side, further guide plates (26) are arranged in the direction of flow near or in front of the baffle (6) to guide the air flow, wherein these guide plates (26) are arranged at a distance from the deflecting air baffles (11) and most preferably in regions with a greater distance between the air baffles (11) and the baffle (6).

15. Method for operating a device (1) for air classification of classifiable material, comprising a housing (10) for an air flow (2) preferably acting against gravity, with an air supply (12) arranged on the housing (10), a material inlet (17) for the material (18) to be classified, at least one first outlet (13) for a first fraction (3) and a second outlet (14) for a second fraction (4), and a baffle (6) arranged between the air supply (12) and the material inlet (17) over the length (L) and width (W) of the housing (10), with a plurality of openings (9) for the predetermined distribution and / or orientation of the air flow (2), characterized in that for adjusting the air flow (2) and / or for cleaning the baffle (6), preferably downstream, the orientation of the openings (9) of the baffle (6) and / or the opening cross-section (19) individual, all or grouped openings (9) are changed.

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