Air dispersion chamber and method for dispersing and shaping a free-flowing material on a forming belt

Abstract

The present invention relates to an air distribution chamber and a method for distributing a free-flowing material (8) on an endless forming belt (12) and forming it into a material fiber web (11) during the production of a material board in a press. The air distribution chamber (10) has a chamber (1) with a material feed opening (22) for introducing the material (8) into an air stream (13). In a first region (I) of the chamber (1), a first space height (2a) is formed by the spacing between a top plate (23) and the forming belt (12), and the space height is implemented to be variable in other regions (II, III, IV) along the flow direction (7). In a second region (II), a wall (4) is arranged below the top plate (23) to continuously reduce the space height (2b), and in a third region (III), a wall (5) is arranged to continuously increase the space height.

Description

Field of the Invention

[0001] The present invention relates to an air spreading chamber for spreading a free-flowing material and forming it into one or more layers of a material fiber web (non-woven fabric / non-woven material / felt / slab stock) on an endless forming belt, preferably during the production of a material board in a press.

[0002] Furthermore, the present invention relates to a method for spreading a free-flowing material and forming it into one or more layers of a material fiber web on an endless forming belt, preferably during the production of a material board in a press. Background Art

[0003] When producing a material board, natural materials such as annual plants, woody shrubs, trees or the like are mainly chopped, dried, mixed with an adhesive if necessary, spread into a material fiber web, and compacted into a material board in a press. It is also contemplated to use plastics or other materials to obtain a flat material strip that can be distributed (classified / divided) during continuous production. It is also conceivable to recycle the material fiber web, for example, to distribute the material fiber web before pressing. Particularly preferably, nowadays in the production of fiberboards and particleboards, natural materials are increasingly being replaced by recycled materials to minimize the material demand for virgin wood. It is common to combine an air spreading chamber with other spreading devices to achieve various layered structures.

[0004] For example, a device and method for air screening are known from DE 198 35 419A1. The prior art described in this document is sufficient to outline any discussion of the prior art of the present invention. From the above disclosure, it is known to use various techniques to influence air flow, particularly air screening devices and suction devices.

[0005] Air forming technology emphasizes the uniform laying of the material. Eddies in the air flow and the separation of the air flow on the walls should be avoided because these can affect the accuracy of the weight per unit area. Today's industry not only requires a high accuracy of the weight per unit area, but also increasingly demands a reduction in the required natural raw materials, while requiring the partial or complete replacement of the raw materials with recycled materials. This is sometimes also a national task in various countries. All these requirements lead to the use of very long air spreading chambers.

[0006] One possibility of reducing the structural length of the air distribution chamber is to arrange more sieves or flow obstacles in the air distribution chamber to speed up the laying of the material. Such an arrangement of a large number of sieves is not desirable because the energy expended to generate ventilation or air flow during operation is wasted unnecessarily without achieving a sufficiently good beneficial effect. This usually also leads to disturbing material accumulation or build-up, which, after hitting the forming belt, significantly enters (counts into) the mat and the subsequent product material sheet compared to the adjacent distribution.

[0007] This type of air distribution chamber is also known from DE 10 2006 038 183 A1 and DE 10 2009 007 944 A1.

[0008] The present invention is particularly based on DE 10 2009 007 944 A1. In this document, an air distribution chamber is proposed which can set different spatial volumes in the air distribution chamber according to different roof heights along the air flow. For this purpose, the roof is implemented as a variable housing which has a variably adjustable roof area. It is hereby provided that the roof heights in different chamber areas should maintain a constant distance relative to the forming belt and thus be oriented parallel to the forming belt. These roof heights can then, for example, adjust their distance from the forming belt in the vertical direction. Between the individual horizontal planes, inclined and / or curved transition parts can be provided in the flow direction, which connect the horizontal planes. In a detailed embodiment, a variant of the air distribution chamber is shown which contains a number of horizontal roof elements arranged at different heights in the flow direction and which are connected accordingly. This arrangement of horizontal and height-adjustable roof elements has basically proven itself in practice but still leaves room for improvement. Summary of the Invention

[0009] The object of the present invention is to provide an air distribution chamber and a method for distributing a freely flowing material on an infinitely circulating forming belt and forming it into one or more layers of a material fiber web, which meets the requirements of the industry for high quality and minimum raw materials with a short and concise structural length.

[0010] The present invention is hereby based on an air distribution chamber which is used for distributing a freely flowing material on an infinitely circulating forming belt and forming it into one or more layers of a material fiber web during the production of a material sheet in a press, wherein the air distribution chamber has a chamber with a material feed opening for introducing the material into the air flow, wherein the air flow is introduced into the chamber through an inlet opening and is preferably discharged via an outlet opening at the other end of the chamber, wherein in a first region of the chamber a first spatial height is formed by the distance between the roof (top / ceiling) and the forming belt, and this spatial height is implemented as variable in other regions in the flow direction.

[0011] The task for the air distribution chamber is solved as follows: In the second region, below the top plate, there is a wall that continuously reduces the space height, and in the third region, there is a wall that continuously increases the space height.

[0012] The present invention analogizes "continuously" with a mathematical or geometric function and understands it as the space height along the wall continuously decreasing or increasing in the flow direction.

[0013] The chamber has a top plate, side walls in front and at the back along the flow direction and transverse to the flow direction, and a bottom plate (bottom). When an open construction is selected, the bottom plate can also be formed by a forming belt.

[0014] Here, the space height is defined as the distance between the forming belt for receiving the material and the top plate or wall of the chamber. According to the present invention, compared with the first region of the chamber where the air flow and the material enter the chamber, the flat top plate is substantially covered by a wall having a predetermined geometric shape, and this wall mainly forms a lower height of the chamber between the forming belt and the wall.

[0015] The wall transverse to the air flow or the forming belt is preferably flat or straight, but can also be fully curved according to the characteristics, or only curved on the outer side, that is, at the side of the chamber. This is useful for adapting to the flow conditions at the wall / side wall transition.

[0016] In a particularly preferred embodiment, the chamber has exactly three or four regions in said regions. In order to delimit the respective regions here, as can be determined as in other embodiments, the inflection point, that is, the lowest point of the wall, defines the boundary between the second region and the third region. The transition between the fourth region and the third region (transition region) is where the rise of the wall ends in the third region and turns into the fourth region of the wall or the top plate arranged parallel to the forming belt. If the rise of the wall continues until the end of the air flow, the chamber has only three regions.

[0017] The transition between the first region and the second region is at the site where the wall with a decreasing space height starting from the top plate begins. In a special variant, the wall has already started after the injection port where the material enters the chamber. Then, the first region will only be the injection port itself, and the space height corresponds to the distance from the forming belt to the injection port or the top plate height.

[0018] A particular advantage of the present invention is that by being able to adjust the respective walls according to the teachings of the present invention, the operator or supplier of the air distribution chamber can now adjust the length of its respective regions according to the application purpose. In a simple type and manner, the inflection point in the chamber can arbitrarily adjust its distance from the forming belt and can also arbitrarily adjust its distance from the entry point where the air flow enters the chamber, and adapt to various needs.

[0019] The present invention also unexpectedly finds that the technical efforts made so far to achieve the most uniform and stable transition of particle sizes in the layer to be dispersed in the air dispersion chamber do not have as great an impact on the quality of the sheet as previously assumed. It is very likely to divide the air dispersion chamber into regions of different heights, where the coarse part (coarse particles) is mainly laid in the first laying area along the flow direction, while the relatively finer particles are in a gentle air flow in the second chamber area. Therefore, due to the expansion of the available space, a rapid and strong air flow in the rear area along the flow direction should be avoided. For this purpose, after the space height is narrowed, the space height is then specifically expanded / increased so that the fine material has the opportunity to float onto the forming belt from the slow air flow. Therefore, a stepped classification is particularly preferably produced, which is caused by the difference in flow velocity. This difference can be supported by flow obstacles, especially in the transition area between the differentiated space heights.

[0020] The present invention can also reduce the structural length of the air dispersion chamber, flow as freely as possible, and preferably eliminate or reduce the conventional flow barriers (sieves) used so far. For this purpose, the flow vector is used to continuously reduce the space height to strengthen the classification, especially in the case where the wall is designed in a droplet shape, which will be introduced in detail later. At the same time, especially when the quality remains unchanged or even improves, the power of the blower can be reduced and / or the throughput per unit time can be increased.

[0021] The wall for changing the space height can be made of (metal) plates or plastics here, preferably made of a low-viscosity material, such as antistatic or low-viscosity for adhesives, so that the material for the material sheet does not adhere to it. The application of natural wood or material sheets can also be envisaged. Particularly preferably, the wall is composed of elastic elements or flexible elements and is therefore adjustable, but most preferably has sufficient resistance or strength (stiffness) so that it will not be deformed or vibrated by the air flow during operation. In an exemplary application, a conveyor belt or a conveyor can be envisaged to be suspended at the top plate in front or behind along the flow direction.

[0022] It should also be noted that the wall or the top plate should be arranged across the entire width of the chamber. Particularly preferably, in order to meet the frictional force or flow conditions at the side walls, the wall can be convex or concave across the entire width.

[0023] The present invention understands the continuous change of the space height as that no horizontal holding line of the wall (especially relative to the forming belt) should be introduced in this area.

[0024] In a particular embodiment, it is conceivable that instead of the reversal point, i.e., the transition from the descending to the ascending spatial height, a holding line is arranged, at which the spatial height changes only slightly. This section constitutes the transition between the regions. By means of such a transition, it is possible to avoid "carrying" the disturbing influences of the previous region "into" the subsequent region. Disturbing influences mean fluid-technical disadvantages such as eddies, different vectors in the velocity or direction of the air flow. The inclination of this section with respect to the forming belt is preferably not more than 25°, particularly preferably the inclination is less than 12.5°, and most preferably less than 5°.

[0025] In another preferred embodiment, the shape of the section or region around the reversal point is a downward arrow, wherein the reversal point forms the vertex, and sections are arranged that are inclined with respect to the forming belt in the flow direction or against the flow direction.

[0026] The air flow is arranged substantially parallel to the forming belt in the region of the chamber. This means that the air flow is guided along the forming belt, wherein even if there may be individual vector differences in the air components of the air flow, for example when the spatial height decreases, the change in the spatial height always causes the air flow to be guided along the forming belt. The air flow can be guided parallel to the forming belt in the inlet region, but an angled air flow is also conceivable in the sense of the present invention, particularly for optimizing the material input or the distribution of the material in the air flow. Thus, it can be considered that in the inlet region where the air flow enters the chamber, if guide plates, nozzles and / or regulators are arranged therein, they do not necessarily have to be implemented in parallel.

[0027] The following shows further cumulative or alternative additional functions, which improve the solution of the task by their interaction:

[0028] Preferably, as long as the solution or teaching of the present invention is satisfied, straight or curved walls can be arranged in the flow direction to change the spatial height.

[0029] Further preferably, screening devices can be arranged in the first region or the subsequent region, preferably screening devices for the coarser parts of the material.

[0030] Furthermore, preferably at least one, preferably two, most preferably three or more screening grids (lattices / meshes) are arranged as screening devices in the air flow. Additionally or alternatively, a coarse sieve and / or a roller bed composed of coaxially arranged spreading rollers can be arranged, particularly for discharging oversized material and removing it from the manufacturing process.

[0031] Alternatively or additionally, within the fourth region, the outlet or at least one other outlet may be arranged on the top plate or the wall of the chamber. In particular, in the fourth region, it is advantageous to remove the air flow from the chamber in the upper region. In one possible alternative, this outlet may be arranged at the top plate above in the fourth region.

[0032] In addition, other outlets may also be arranged on the wall or the top plate at the transition between the third region and the fourth region, so as to partially discharge the air flow from the chamber without eddy currents.

[0033] Regarding the second and / or third regions, a wall that reduces the space height along the first straight line or the second curvature (bend) may be arranged in the second region, and a wall that increases the space height along the second straight line or the second curvature (bend) may be arranged in the third region after the inversion point.

[0034] Particularly preferably, in the side sectional view of the chamber, at least the curvature (bend) of the wall substantially has the geometric outer side of half a droplet intercepted along its symmetry plane. Here, the geometric outer side preferably shows a change from a hemispherical shape to the vertex or vice versa (from the vertex to the hemispherical shape) in the chamber. The droplet shape of the present invention is a ball that tapers to one side, which physically occurs just before the droplet separates, that is, during the droplet formation process. However, the wall preferably does not follow the droplet shape in the width of the forming belt, but is flat or arranged parallel to the forming belt.

[0035] In the first option, the first radius of curvature of the wall in the first region may be implemented to be smaller than the second radius of curvature, and preferably, the ratio of the first radius to the second radius may be 1:2, preferably 1:5, and particularly preferably 1:10.

[0036] In the second option, the first radius of curvature of the wall in the first region may be implemented to be larger than the second radius of curvature, and preferably, the ratio of the first radius to the second radius may be 2:1, preferably 5:1, and particularly preferably 10:1.

[0037] Particularly preferably, the radius of curvature of the second region or the third region is designed to decrease and / or increase along the air flow. This helps the uniformity of the air flow and avoids turbulence. Preferably, in such a geometry, the walls transverse to the forming belt are also implemented to be substantially parallel.

[0038] Alternatively or additionally (cumulatively), the geometry of the wall can be arranged unchanged to adjust the height of the space. This can represent a fixed geometry. This is particularly advantageous if the geometry of the wall is formed based on a simulation (simulation) calculation of the flow characteristics of the air flow and has thus been optimized. In this way, there is no need to make different settings for optimization during operation. This is particularly advantageous if the material or material mixture used to produce the material web does not undergo any influential changes during the production process.

[0039] If in the application of industrial technology it is stipulated to change the material throughput per unit time, the possibility of adjusting one or more walls can be preferred (considered).

[0040] For example, the material mixture can consist of fibers, chips, and shavings from "fresh" wood, where it is meant that these particles come on the one hand from the processing (cutting) manufacturing process directly used for board production or as waste from wood production (sawmills, cut-off machines, chippers), and thus from untreated wood, and on the other hand are mixed with waste wood from recycling.

[0041] Preferably, if any, the space height of the fourth region of the chamber is lower than that of the first region. If the wall extends into the fourth region, this also applies to the wall if possible.

[0042] In another preferred embodiment, the shape of this section is a downward arrow, where the inversion point forms the vertex and there are sections arranged inclined in the flow direction or against the flow direction relative to the forming belt.

[0043] In a preferred alternative, the wall in the second and third regions can be symmetric about a symmetry plane perpendicular to the forming belt and passing through the inversion point. In addition to the possibility of reducing production costs by using the same components, similar air flow compression and expansion characteristics can also be produced.

[0044] In another preferred alternative, in the second region along the flow direction, the space height can decrease along a negative gradient, while in the third region along the flow direction, the space height can increase along a positive gradient. This is mainly to avoid turbulence.

[0045] To improve the teaching of the present invention, flow obstacles can be arranged between the forming belt and the wall in the second and third regions and / or at the height of the inversion point. This helps to lay (deposit) the material faster and helps to shorten the structural length of the air dispersion chamber.

[0046] Preferably, the flow obstacle can be designed as a grid, bars and / or rotating rollers. Preferably, the grid, sieve or rod-shaped structure can be designed to be variable horizontally and / or vertically in terms of its length or dimensions. Here, the flow obstacle can start directly above the material on the forming belt or as close as possible thereto, and reach the wall, or provide a spacing between the forming belt and the wall. For example, an attempt can be made to arrange a free area in the region between the wall and the flow obstacle so that the flow is not abruptly slowed down. In this regard, it would be advantageous if the flow obstacle were arranged at a spacing from the wall and / or from the forming belt / fiber web of the material.

[0047] It would be advantageous if the flow obstacle were arranged such that its position and / or its position in the chamber is adjustable, and preferably the adjustability is achieved by a controllable servo device.

[0048] In another alternative or cumulative embodiment, the walls in the second and third regions preferably together with the wall in the fourth region can be hinged to each other or form an integral unit. Here, the hinge can have means that define a maximum rotation angle or a preset angular range. This is particularly advantageous if the servo device is arranged on the suspension (suspension device / suspension part / suspension point) of the wall or on the wall itself.

[0049] In another particularly preferred embodiment, the wall has in a side view of the chamber the shape of half an idealized droplet intercepted at the symmetry line of the droplet (in the side view). Thus, instead of a circle in the sole drawing, the shape of half a droplet of the wall can be seen. Here, the section in the drawing is perpendicular to the symmetry plane of the droplet, and the symmetry plane is arranged parallel to the top plate of the chamber. Here, the vertex of the droplet should be oriented along or against the air flow.

[0050] Preferably, the wall can be implemented in the form of a flexible belt or strip, preferably made of a material similar to or used for conveyor belts. Here, a rubber mixture with or without reinforcement can be used.

[0051] Preferably, it has an inherent stiffness that provides sufficient resistance to the air flow without allowing significant deformation. The flexible belt or strip provides sufficient flexibility for the adjustment or regulation of the conceivable wall, usually combined with good antistatic properties. They also offer the possibility of compensating for changes in the geometry of the chamber caused by temperature fluctuations during operation.

[0052] In order to be able to optimally calibrate the performance of the wall during operation, it can be provided that reinforcement elements, preferably adjustable or adaptable reinforcement elements, are arranged inside the wall and / or along the top plate side surface of the wall. Here, the inherent stiffness of the wall can be increased and / or adjusted in combination with adjustment elements or other calibration means. These can be set statically before commissioning or implemented to be dynamically adjustable during operation.

[0053] Preferably, it is provided that, especially for forming a droplet shape, the rear part (rear portion) of the wall, seen in the flow direction, is stiffer than the part of the wall in front of it. Thus, in the case of being suspended and mounted on the top plate, the rear part is steeply oriented towards the forming belt and only starts to form a curve (against the flow direction) at the end of the reinforcing part. This almost automatically forms a droplet shape, which can be particularly preferably supported correspondingly by the mutual connection of the two ends of the wall or the connection to the top plate and the spacer element or the reinforcing element.

[0054] It is further advantageous if the wall has a reinforcing part transverse to the flow direction, preferably over the entire width, in the center and / or near the side wall or in the area of the side wall. Thereby, the pressure increase caused by the air flow and / or the material in the chamber at the side wall / wall transition can be offset.

[0055] Furthermore, the present invention understands "transverse to the forming belt" as being oriented transverse to the conveying direction of the forming belt. Similarly, the term "over the (entire) width of the forming belt" can be understood, since the forming belt is arranged in a loop over its length and has a certain width. The width of the forming belt basically corresponds to the width of the chamber, where deviations at the edges can be envisaged according to the sealing principle.

[0056] Alternatively or additionally, it can be provided that a sealing element, preferably a sealing lip on the wall, is arranged between the side wall and the wall of the chamber. Thereby, the area between the wall and the top plate is prevented from being contaminated. If no material is introduced here, it can also improve the adjustment performance of the wall.

[0057] Another particular embodiment is to arrange fixing points, preferably adjustable fixing points, on at least one side wall and / or on one of the walls. For example, if the wall itself cannot achieve it, such fixing points can be used to give (determine) or influence a certain shape. When these walls are moved by a servo drive, such fixing points can also be adapted to influence the shape of the wall.

[0058] In particular, it can be provided that the reversal point is fixedly arranged as the minimum space height, while the shape of the wall, such as an integral or articulated strip, moves at its suspension point and thus changes the gradient of the ascending and descending space height. This fixing point can also be realized from the outside by insertable bolts, which can be inserted into or removed from the predetermined closable holes (drill holes) of the chamber. These can also be automated and / or adjustable in terms of height and position along the chamber in a sliding groove.

[0059] Alternatively or additionally (cumulatively), fixed connecting elements and / or adjusting elements for influencing the geometry of the wall are arranged in operative connection with the wall and the ceiling panel. Here, by means of the ceiling panel, a slide or a similar machine element can raise (lift / elevate) the wall or press the wall down at a predefined position. It is possible to form complex geometries of the spatial height. Although there is an increased structural outlay, it is an advantageous possibility to have a separate wall provided indoors or below the ceiling panel.

[0060] In the sense of a continuous wall, a one-piece wall can be arranged in several regions, i.e., the start of the wall is in the second region and the end of the wall is in the third or fourth region, where preferably only the start and the end of the wall are arranged at the ceiling panel.

[0061] In particular, but not limited to this embodiment, the position of the wall indoors and / or the adjustment of the geometry of the wall or the start and / or the end of the wall can be adjustable by means of a displacement (sliding) device, preferably parallel to the ceiling panel. For this purpose, a simple slide can be arranged on the ceiling panel, preferably parallel to the forming belt, which slide at least displaces the suspension (suspension point) of the wall. However, this slide can also connect two walls and displace them relative to each other to adjust the geometry of the wall and / or the position of the wall or the suspension (suspension point).

[0062] It can be provided that one of the plurality of walls or the wall is vibrated by an actuator (actuating device). This is done not only for cleaning but also to support the adjustment of the wall or to reduce the stress in the wall.

[0063] Preferably, only at the reversal point along the flow direction, the spatial height of the second region and the third region is equal.

[0064] In a specific embodiment, a retaining line can be arranged in the region of the reversal point at the adjacent parts of the wall, where the spatial height changes only slightly at the retaining line.

[0065] The inclination angle of the retaining line relative to the forming belt can be implemented here to be less than 25°, particularly preferably less than 12.5°, and most preferably less than 5°.

[0066] More specifically, the retaining line starting from the reversal point can extend in two adjacent regions of the wall and is particularly preferably formed as a downward arrow, where the reversal point forms the vertex and is provided with segments inclined relative to the forming belt along the flow direction or against the flow direction.

[0067] These prior embodiments can improve the turbulence problem within or at the reversal point by technical means, and in particular can be achieved by arranging a hinge at the reversal point between two walls, wherein the hinge particularly preferably has an inherent stiffness or a predetermined angle for adjusting the vertex. Special reinforcements on the walls that are generally flexibly adjustable can also be used to produce a specific geometry.

[0068] The present invention understands the term "flexible wall" to mean that the geometry of the wall can be influenced by an adjustment device or other means. Here, it is preferably ensured that the air flow and the material inside the chamber do not cause changes in the geometry during operation.

[0069] As a further measure for adjusting the chamber and the clearance (interaction) with the wall, the number, structure, orientation, size, and penetrability (permeability) of all sieves (e.g., screening devices, sieves) in the chamber can be designed to be variably adjustable (adapted), preferably by a servo drive.

[0070] For designing a fixed geometry or adjustability, it can be provided that locking elements, preferably magnets and / or regions protruding from the wall / side wall, are arranged laterally on the wall, and these elements are preferably operatively connected to the corresponding supports at the side wall / wall, or can be made to establish an operative connection during the process of adjusting the geometry of the wall. In order to increase the stability of the transition between the wall / side wall and the durability against the air flow, these measures are useful in certain cases (indicated). These means also seem to be meaningful for the reproducibility (repeatability) of the adjustable wall geometry.

[0071] Grooves, blind holes (blind drill holes), protrusions, magnets, and / or other machine elements can be arranged on the inner side or inside of the side wall, and together with the corresponding supports of the wall, they exert a locking or holding function. This also applies vice versa. In order to increase the stability of the transition region between the wall / side wall and the durability against the air flow, these measures are useful in certain cases. In the case of operation-related changes in the geometry of the wall, it is meaningful to predetermine the locking position by means of an intervention or marking on the side wall. This is particularly used to reproduce the adjustment (setting) of the wall geometry in a specific production mode or to be able to return to a previous adjustment (setting) in a precisely fitting manner.

[0072] The above individual features / each feature can also be implemented in terms of process technology, especially in combination with process-executable changes to the geometry of the wall in different production modes.

[0073] A corresponding method for spreading a freely flowing material on a forming belt in an infinite loop and forming it into a single - layer or multi - layer fibrous material web during the production of a material board in a press is based on a known air - spreading chamber, which has a chamber with a material feed port for introducing the material into the air stream, wherein the air stream is introduced into the chamber through an inlet in a first region and discharged through an outlet at the other end of the chamber, and the distance between the top plate of the chamber and the forming belt constitutes the space height.

[0074] The task of the method is solved in such a way that, in the flow direction, the space height decreases in a second region and the space height continuously increases in a third region by means of a wall between the top plate and the forming belt.

[0075] Particularly preferably, in the second or third region, at the boundary between the two regions, the air stream is guided by a flow obstacle, such as a sieve, so that the coarser (granular) parts in the material are deposited on the forming belt more quickly.

[0076] Furthermore, the features and advantages shown in connection with the air - spreading chamber according to the invention and the method according to the invention and their corresponding advantageous design configurations are adapted to each other correspondingly, and vice versa.

[0077] The individual features and advantages separated in the above paragraphs can be interchanged or combined with each other as required, and further beneficial effects exceeding the sum of the individual effects can be produced. Description of the Drawings

[0078] Other advantages, features and details of the invention are given by the following description, in which embodiments of the invention are further explained with reference to the drawings.

[0079] For a person skilled in the art, the features disclosed in combination in the drawings, the description and the claims are suitable for being considered separately and can meaningfully be summarized into other combinations. Detailed Description of the Invention

[0080] The figure schematically shows an air - spreading chamber for producing a fibrous material web (non - woven fabric / non - woven material / felt / slab stock bed) on a forming belt during the production of a material board, wherein a wall for changing the space height is arranged in the air - spreading chamber.

[0081] As can be seen from the figure, the material 8 is introduced into chamber 1 of the air dispersion chamber 10 through the material feed port 22, moves in a direction opposite to the conveying direction of the forming belt 12 along the air flow 13, and is laid on the forming belt 12 as a material web 11 in regions I, II, III, and IV of chamber 1. In this example, a roller for loosening the material is arranged above the air flow 13. The air flow 13 reaching through the air feed port 24 enters chamber 1 through the inlet 14, causing the material 8 to move along the flow direction 7 of the air flow 13. Chamber 1 is divided into regions I, II, III, and IV, and the air flow 13 successively flows through these regions corresponding to the numbers. In the first region I, the top plate (ceiling) 23 and the forming belt 12 bounding chamber 1 below together form a space height 2a. The material flows through the screening device 17 together with the air flow, and at least one screening grid 18 is arranged in the screening device. Preferably, as shown in the figure, the coarse screen 19 can be arranged substantially parallel to the forming belt, and the coarse screen separates oversized material from the process through its operative connection (effective connection) with the discharge device 25. Additionally, instead of the coarse screen 17, a roller screen formed by coaxial rollers can be arranged to equalize the arriving material 8.

[0082] At the transition (transition region) to the second region II, the space height 2a changes to a space height 2b by means of the arranged wall 4. The wall 4 can exhibit different geometries and has a minimum space height 2b at the end of region II along the flow direction 7. The reversal point 9 is also located there, which marks the transition to the third region III, where the wall 5 is arranged such that the space height 2c increases again along the flow direction 7.

[0083] The walls 4, 5, and 6 can have different geometries, where in this embodiment, the first wall 4 has a first radius 20 and the second wall 5 has a second radius 21. These radii can be implemented as equal, but they can also be unequal.

[0084] At the end of the third region III, a region IV with a space height 2d is arranged, and this region IV has an outlet 15 at the end, through which the air flow 13 can be taken out of chamber 1 again. Alternatively, the outlet 15 can be arranged on the top plate 23 or, if any, on the wall 6 located in this region. The wall 6 or the top plate 23 can form a space height 2d that is lower than the space height 2a in the first region I here.

[0085] Particularly preferably, an additional or separate outlet 16 is arranged at the transition (transition region) between the third region III and the fourth region IV.

[0086] To support the Venturi constriction of chamber 1, a flow obstacle 3 can be arranged in the second region II or the third region III, which can decelerate the air flow 13 or the material 8 in the air flow 13. Through the flow obstacle 3, in particular, the still relatively large material particles 8 are decelerated and moved towards the forming belt 12.

[0087] In this embodiment, the covering layer is scattered. If there are other scatterers and / or air scatter chambers arranged in the running direction of the forming belt 12, the finest particles (finest part) of the material 8 first reach the forming belt 12, which moves against the air flow 13 or the flow direction 7, and form a partial layer of the multi-layer material fiber web 11. Then, the next air scatter chamber will be arranged laterally reversed in order to lay the smallest particles on the resulting surface of the material fiber web.

[0088] The preferred droplet shapes of the walls 4 and 5 are not shown in the figure. However, by way of example, it is pointed out that the wall 5 has a preferably approximately straight reinforcing part in the rear region; the wall 5 is drawn relatively thick here. This is useful in the case of the flexible material of the wall in order to better reproduce the geometry of the wall. For example, in the case of the wall 5, the increasing gradient of the space height 2c is greater compared to the decreasing gradient of the space height 2b. In particular, through the slider (symbolically represented by a double arrow) at the top plate 23, the suspension (suspension device / suspension point) of the wall 4 can move against the air flow 13. The reinforcing part will flatten the curvature along the wall 4, while the curvature 5 will change less (change less strongly) due to the extension of the distance between the suspensions (suspension devices / suspension points) of the walls 4 and 5.

[0089] List of reference numerals:

[0090] 1 chamber

[0091] 2a space height

[0092] 2b space height

[0093] 2c space height

[0094] 2d space height

[0095] 3 flow obstacle

[0096] 4 wall

[0097] 5 wall

[0098] 6 wall

[0099] 7 flow direction

[0100] 8 material

[0101] 9 reversal point

[0102] 10 air scatter chamber

[0103] 11 Material fiber web

[0104] 12 Forming belt

[0105] 13 Airflow

[0106] 14 Inlet

[0107] 15 Outlet

[0108] 16 (Second) outlet

[0109] 17 Screening device

[0110] 18 Screening grid

[0111] 19 Coarse screen

[0112] 20 (First) radius

[0113] 21 (Second) radius

[0114] 22 Material feeding section

[0115] 23 Top plate

[0116] 24 Air feeding port

[0117] 25 Discharge device

[0118] Zone I

[0119] Zone II

[0120] Zone III

[0121] Zone IV.

Claims

1. An air spreading chamber for spreading a free-flowing material (8) on an infinitely circulating forming belt (12) and forming it into one or more layers of a fibrous web (11), wherein, The air dispersion chamber (10) has a chamber (1) with a material feed port (22) for introducing the material (8) into the air stream (13), wherein the air stream (13) is introduced into the chamber (1) through an inlet (14), wherein a first space height (2a) is formed in a first region (I) of the chamber (1) by the spacing between a top plate (23) and the forming belt (12), and there are also a second region (II) with a second space height (2b) and a third region (III) with a third space height (2c) in the chamber (1), and the second space height (2b) and the third space height (2c) are implemented to be variable in the second region (II) and the third region (III) respectively along the flow direction (7) of the air stream (13), characterized in that, in the second region (II), a first wall (4) is arranged below the top plate (23) to continuously and continuously reduce the second space height (2b) along a first straight line or a first curvature, and in the third region (III) directly adjacent to the second region, a second wall (5) is arranged to continuously and continuously increase the third space height (2c) after an inversion point (9) along a second straight line or a second curvature, wherein the inversion point is the point directly connecting between the second region and the third region, the chamber (1) also has a fourth region (IV), in which a first outlet (15) is arranged, or a second outlet (16) is arranged at a third wall (6) or the top plate (23) of the fourth region (IV) of the chamber (1).

2. The air spreading chamber according to claim 1, characterized in that, In the first region (I), a screening device (17) for the coarser part of the material (8) is arranged.

3. The air spreading chamber according to claim 2, characterized in that, As the screening device (17), at least one screening grid (18) and / or a coarse sieve (19) and / or a roller bed composed of coaxially arranged dispersion rollers are arranged in the air stream (13).

4. The air spreading chamber according to claim 1, characterized in that, The outer side of the geometry of the droplet is arranged, partially along the symmetry axis of the droplet shape, as the curvature of the first wall and the second wall.

5. The air spreading chamber according to claim 1, characterized in that, The first curvature radius (20) of the first wall (4) is implemented to be smaller than the second curvature radius (21) of the second wall (5).

6. The air spreading chamber according to claim 1, characterized in that, The first curvature radius (20) of the first wall (4) is implemented to be larger than the second curvature radius (21) of the second wall (5).

7. The air spreading chamber according to claim 5 or 6, characterized in that, The first curvature radius (20) is set to decrease or increase along the air stream in the second region (II) or the second curvature radius (21) is set to decrease or increase in the third region (III).

8. The air spreading chamber according to any one of claims 1 - 6, characterized in that, The geometry of the walls for adjusting the second and third space heights is set to be unchanged.

9. The air spreading chamber according to any one of claims 1 - 6, characterized in that, The geometry of the first wall, the second wall or the third wall is implemented based on the simulation calculation of the flow characteristics of the air stream.

10. The air spreading chamber according to any one of claims 1 - 6, characterized in that, A fourth space height (2d) in the fourth region (IV) of the chamber (1) is smaller than the first space height (2a) in the first region (I) and / or the third wall (6) extends into the fourth region (IV).

11. The air spreading chamber according to claim 1, characterized in that, At the reversal point (9), there is a section where the second space height (2b) and the third space height (2c) change only slightly.

12. The air spreading chamber according to claim 1 or 11, characterized in that, The first wall is implemented symmetrically with respect to a symmetry plane within the second region (II), and the second wall is implemented symmetrically with respect to the symmetry plane within the third region (III). The symmetry plane is perpendicular to the forming belt and passes through the reversal point.

13. The air spreading chamber according to any one of claims 1 - 6, characterized in that, Within the second region (II), along the flow direction (7), the second space height (2b) decreases along a negative gradient, while within the third region (III), along the flow direction (7), the third space height (2c) increases along a positive gradient.

14. The air spreading chamber according to claim 1 or 11, characterized in that, Within the second region (II), a flow obstacle (3) is arranged between the forming belt (12) and the first wall; within the third region (III), a flow obstacle (3) is arranged between the forming belt (12) and the second wall; and / or at the height of the reversal point (9), a flow obstacle (3) is arranged between the forming belt (12) and the reversal point.

15. The air spreading chamber according to claim 14, characterized in that, As the flow obstacle (3), a grille, bars, and / or rotating rollers are arranged.

16. The air spreading chamber according to claim 14, characterized in that, Within the second region (II), the flow obstacle (3) is arranged spaced apart from the first wall and / or from the forming belt (12); within the third region (III), the flow obstacle (3) is arranged spaced apart from the second wall and / or from the forming belt (12); or at the height of the reversal point (9), the flow obstacle (3) is arranged spaced apart from the forming belt (12) and / or from the reversal point.

17. The air spreading chamber according to claim 14, characterized in that, The position and / or location of the flow obstacle (3) within the chamber (1) are set to be adjustable.

18. The air spreading chamber according to any one of claims 1 - 6, characterized in that, The first wall in the second region (II) and the second wall in the third region (III) are connected to each other hingedly or are formed integrally.

19. The air dispersion chamber according to any one of claims 1-4, characterized in that The first wall and the second wall form the outer shape of half a droplet intercepted at the symmetry line of a droplet in a side view of the chamber (1), wherein the symmetry line of the droplet is arranged parallel to the top plate (23) of the chamber (1).

20. The air dispersion chamber according to any one of claims 1-6, characterized in that The first wall, the second wall, or the third wall is arranged as a belt.

21. The air dispersion chamber according to any one of claims 1-6, characterized in that The first wall, the second wall, or the third wall is arranged as a flexible belt.

22. The air dispersion chamber according to any one of claims 1-6, characterized in that Reinforcing elements are arranged inside the first wall, the second wall, or the third wall and / or along the surface of the top plate side of the first wall, the second wall, or the third wall.

23. The air dispersion chamber according to claim 4, characterized in that In order to form the droplet shape of the wall, when viewed along the flow direction (7), the rear portions of the second wall (5) and the third wall (6) are constructed to be more rigid than the first portions of the first wall (4) and the second wall (5).

24. The air dispersion chamber according to any one of claims 1-6, characterized in that The first wall, the second wall, or the third wall has a reinforcing portion transverse to the flow direction (7).

25. The air dispersion chamber according to any one of claims 1-6, characterized in that Sealing elements are arranged between the side wall of the chamber (1) and the first wall, between the side wall of the chamber (1) and the second wall, and between the side wall of the chamber (1) and the third wall.

26. The air dispersion chamber according to any one of claims 1-6, characterized in that Fixing points are arranged at least at the side wall of the chamber (1) and / or fixing points operatively connected to the side wall of the chamber (1) are arranged at the first wall, the second wall, or the third wall.

27. The air dispersion chamber according to any one of claims 1-6, characterized in that The fixed connecting elements and / or adjusting elements are arranged in operative connection with the first wall, the second wall or the third wall and the top plate (23) in order to influence the geometry of the first wall, the second wall or the third wall.

28. The air dispersion chamber according to any one of claims 1-6, characterized in that In the case of an integral wall extending over a plurality of regions (II, III, IV), the start of the first wall (4) in the second region (II) and the end of the second wall (5) in the third region (III) or the end of the third wall (6) in the fourth region (IV) are respectively arranged at the top plate (23).

29. The air dispersion chamber according to any one of claims 1-6, characterized in that In order to adjust the position of the first wall, the second wall or the third wall within the chamber (1) and / or the geometry of the first wall, the second wall or the third wall, the start and / or end of the first wall, the second wall or the third wall is in operative connection with a displacement device.

30. The air dispersion chamber according to claim 29, characterized in that The displacement device is parallel to the top plate (23).

31. The air dispersion chamber according to any one of claims 1-6, characterized in that In order to excite the first wall, the second wall or the third wall by vibration, at least one excitation device is arranged.

32. The air dispersion chamber according to claim 1 or 11, characterized in that Only at the reversal point (9) along the flow direction (7), the spatial height of the second region (II) and the third region (III) is equal.

33. The air dispersion chamber according to claim 1 or 11, characterized in that Retention lines are arranged in the region of the reversal point (9) at the first wall (4) and the second wall (5), and the spatial height varies only slightly at the retention lines.

34. The air dispersion chamber according to claim 33, characterized in that The inclination angle of the retention line relative to the forming belt is implemented to be less than 25°.

35. The air dispersion chamber according to claim 33, characterized in that The retention line extends from the reversal point in two adjacent regions of the first wall (4) and the second wall (5), wherein the reversal point (9) forms a vertex, and there are segments inclined relative to the forming belt (12) along the flow direction or against the flow direction.

36. The air dispersion chamber according to claim 2 or 3, characterized in that The number, structure, orientation, size and penetrability of the screening device (17) in the chamber (1) are implemented to be variably adjustable.

37. The air dispersion chamber according to any one of claims 1-6, characterized in thatLocking elements are arranged laterally at the first wall, the second wall or the third wall, and the locking elements can be in operative connection with corresponding supports at the side walls of the chamber (1), or can establish operative connection during the process of adjusting the geometry of the first wall, the second wall or the third wall.

38. The wind dispersion chamber according to any one of claims 1-6, characterized in that, Grooves, blind holes, protrusions, magnets and / or other mechanical elements are arranged on the inner side of the side walls of the chamber (1) or in the side walls, and the grooves, blind holes, protrusions, magnets and / or other mechanical elements together with the corresponding supports of the first wall, the second wall or the third wall perform the locking or retaining function.

39. The wind dispersion chamber according to any one of claims 1-6, characterized in that, The air dispersion chamber is used to disperse the material (8) and form it into the one or more layers of material fiber web during the production of material plates in a press.

40. The wind dispersion chamber according to any one of claims 1-6, characterized in that, The air flow (13) is discharged via a first flow outlet (15) at the other end of the chamber (1).

41. The wind dispersion chamber according to claim 2, characterized in that, As the screening device (17), two screening grids (18) and / or coarse sieves (19) and / or a roller bed composed of coaxially arranged dispersion rollers are arranged in the air flow (13).

42. The wind dispersion chamber according to claim 2, characterized in that, As the screening device (17), three or more screening grids (18) and / or coarse sieves (19) and / or a roller bed composed of coaxially arranged dispersion rollers are arranged in the air flow (13).

43. The wind dispersion chamber according to claim 4, characterized in that, The outer side of the geometry is implemented to be from a hemispherical shape towards the vertex.

44. The wind dispersion chamber according to claim 4, characterized in that, The first wall, the second wall, or the third wall is implemented as substantially flat in the width of the chamber (1).

45. The wind dispersion chamber according to claim 5, characterized in that, The ratio of the first radius of curvature (20) to the second radius of curvature (21) is set to 1 to 2.

46. The wind dispersion chamber according to claim 5, characterized in that, The ratio of the first radius of curvature (20) to the second radius of curvature (21) is set to 1 to 5.

47. The wind dispersion chamber according to claim 5, characterized in that, The ratio of the first radius of curvature (20) to the second radius of curvature (21) is set to 1 to 10.

48. The wind dispersion chamber according to claim 6, characterized in that, The ratio of the first radius of curvature (20) to the second radius of curvature (21) is set to 2 to 1.

49. The wind dispersion chamber according to claim 6, characterized in that, The ratio of the first radius of curvature (20) to the second radius of curvature (21) is set to 5 to 1.

50. The wind dispersion chamber according to claim 6, characterized in that, The ratio of the first radius of curvature (20) to the second radius of curvature (21) is set to 10 to 1.

51. The wind dispersion chamber according to any one of claims 1 to 6, characterized in that, The geometry of the first wall, the second wall, or the third wall is implemented based on a simulation calculation of the flow characteristics of the air flow and is a static setting.

52. The wind dispersion chamber according to claim 14, characterized in that, The flow obstacle (3) is arranged at a distance from the first wall (4), the second wall (5), and / or from the forming belt (12), and is implemented such that its length is variable.

53. The wind dispersion chamber according to claim 51, characterized in that, The orientation of the flow obstacle (3) within the chamber (1) is set to be adjustable.

54. The wind dispersion chamber according to claim 52, characterized in that, The adjustability of the flow obstacle (3) is implemented by a controllable servo device.

55. The wind dispersion chamber according to any one of claims 1-6, characterized in that, The first wall (4) in the second region (II) and the second wall (5) in the third region (III) are connected to each other hingedly or are formed integrally with the third wall (6) of the fourth region (IV).

56. The wind dispersion chamber according to claim 19, characterized in that, The apex of the droplet is oriented against the air flow (13).

57. The air distribution chamber according to claim 20, wherein, The belt has an inherent stiffness that provides sufficient resistance to the air flow (13) without deforming.

58. The air distribution chamber according to claim 21, wherein, The flexible belt has an inherent stiffness that provides sufficient resistance to the air flow (13) without deforming.

59. The air distribution chamber according to claim 22, wherein, The strengthening element is an adjustable or adaptable strengthening element.

60. The air distribution chamber according to claim 24, wherein, The strengthening part is within the region of the side wall of the chamber (1).

61. The air distribution chamber according to claim 25, wherein, The sealing element is a sealing lip at the first wall, the second wall, and the third wall.

62. The air distribution chamber according to claim 26, wherein, The fixing point is an adjustable fixing point.

63. The air distribution chamber according to claim 34, wherein, The inclination angle of the holding line relative to the forming belt is implemented to be less than 12.5°.

64. The air distribution chamber according to claim 34, wherein, The inclination angle of the holding line relative to the forming belt is implemented to be less than 5°.

65. The air distribution chamber according to claim 35, wherein, The holding line is formed as a downward arrow.

66. The air distribution chamber according to any one of claims 2 or 3, wherein, The number, structure, orientation, dimensions, and penetrability of the screening device (17) in the chamber (1) are implemented to be variably adjustable by a servo drive.

67. The air distribution chamber according to claim 37, wherein, The laterally arranged locking elements are magnets and / or regions protruding from the first wall, the second wall, or the third wall.

68. The air distribution chamber according to any one of claims 1 to 6, wherein, In the chamber (1), four regions (I, II, III, IV) with spatial heights (2a, 2b, 2c, 2d) are arranged.

69. A method for distributing a free-flowing material on an infinitely circulating forming belt and forming it into one or more layers of a fibrous web, wherein, The air dispersion chamber has a chamber with a material feed port for introducing the material into the air flow, wherein the air flow is introduced into the chamber in the first region through an inlet. Among them, the distance between the top plate of the chamber and the forming belt forms different spatial heights. It is characterized in that in the second region along the flow direction of the air flow, the second spatial height continuously and continuously decreases along a first straight line or a first curvature through a first wall, while in a third region directly adjacent to the second region, after the inversion point, the third spatial height continuously and continuously increases along a second straight line or a second curvature through a second wall located between the top plate and the forming belt, wherein the inversion point is a point directly connecting between the second region and the third region. The chamber has a fourth region, in which a first flow outlet is arranged, or a second flow outlet is arranged at a third wall or the top plate of the fourth region of the chamber.

70. The method according to claim 69, wherein, At the transition between the second region and the third region, the air flow is guided by a flow obstacle.

71. The method according to claim 69, wherein, The method is used to spread the material and form it into the one or more layers of material fiber webs during the process of producing a material plate in a press.

72. The method according to claim 69, wherein, The air flow is discharged via the first flow outlet or the second flow outlet at the other end of the chamber.

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