Method and apparatus for the production of a particle based element with several tools in the particle dispersing section

Abstract

 The present invention relates to a method for the production of a particle based element, in particular a particle board or fiber board. Particles are dispersed in a dispersing section 5 to form a particle mass 7, while the particle mass 7 and the dispersing section 5 are moving relative to each other in a conveying direction C. The second particles 9 are arranged in a predetermined pattern with respect to first particles 2 in the particle mass, wherein the first and second particles 2,9 have different properties. The second particles 9 are provided in the particle mass 7 by means of several tools 8 being arranged in a spaced relationship substantially in the conveying direction C in the dispersing section 5 above the upper part of the particle mass 7. The invention further relates to an apparatus 1 for the production of a particle based element, in particular a particle board or fiber board, with a dispersing section 5 in which particles are dispersed, and several tools 8 for providing particles 9 with different properties, wherein the tools 8 are arranged in the dispersing section 5 and at least one tool 8 has a generally convex upper side facing the flow of particles 2 in the dispersing section 5.

Description

[0001] The present invention relates to a method for the production of a particle based element, in particular a particle board or fiber board and an apparatus for the production of a particle based element as defined in the preambles of the respective independent claims.

[0002] It is known in the prior art to provide particles with different properties in a particle mass. WO 2011/079934 A1 discloses the provision of particles with different properties either by treatment of particles or by inserting further particles with different properties. In one embodiment it is disclosed that tools can be provided in a dispersing section, in which the particle mass is formed by distributing the particles to form a particle mass. The tools are moved reciprocatingly in a direction along the upper side of the particle mass in the dispersing section, such that particles with different properties are arranged in a wave form in the particle mass.

[0003] It is the object of the invention to provide a method and an apparatus for the production of a particle based element in which the provision of particles with different properties in a particle mass is improved, in particular regarding the distribution precision of the different particles in the particle mass.

[0004] Therefore, the invention provides a method for the production of a particle based element, in particular a particle board or fiber board, comprising dispersing particles in a dispersing section to form a particle mass, while the particle mass and the dispersing section are moving relative to each other in a conveying direction, such that the second particles are arranged in a predetermined pattern with respect to first particles in the particle mass, the first and second particles having different properties, and providing the second particles in the particle mass by means of several tools being arranged in a spaced relationship substantially in the conveying direction in the dispersing section above the upper part of the particle mass. The relative movement of the particle mass and the dispersing section can be obtained by dispersing the particles in a stationary dispersing section on a movable part, such as a conveyor belt. Alternatively, a movable dispersing section can be moved over a stationary surface on which the particle mass is provided. The predetermined pattern of the second particles may for example be a wavelike form in one of the directions in the particle based element or in several directions of the particle based element. In particular, the wavelike form may connect the lower part and the upper part of a particle mass. However, various other forms of the predetermined pattern are possible, such as for example a zig-zag structure or linear inclined planes of particles with different properties in a particle mass. These inclined planes may preferably have an angle of 45° with respect to the main extension plane of the particle mass. The provision of the second particles relates either to the treatment of particles or to the additional insertion of particles. The spaced relationship substantially in the conveying direction of the several tools allows that even when the tools remain stationary, different layers of the particle mass can be treated or particles can be inserted into different layers of the particle mass to allow the formation of the predetermined pattern. In particular, the tools can be arranged in the area of the dispersing section, wherein the particles are falling substantially in a vertical direction on the particle mass. Preferably, the tools are arranged, such that they provide particles on the upper part of the particle mass during the formation of the particle mass, that is the tools are arranged along the upper part of the particle mass, on which the particles fall. The upper part of the particle mass is slightly inclined with respect to the conveying direction in the dispersing section. The tools may either only provide the particles at discrete points or along a line in the width direction of the particle mass. The width direction of the particle mass is perpendicular to the conveying direction and the height direction. The tools may provide particles in several discrete locations along the width direction of the particle mass.

[0005] In contrast to the prior art, the arrangement of several tools in a spaced relationship substantially in the conveying direction allows that the tools do not have to be moved along significant distances and therefore enables that the dispersing of the particles in the dispersing section is less disturbed and the particles are substantially evenly distributed. The most upstream arranged tools with respect to the conveying direction allow a treatment of the lowermost particles while the most downstream arranged tools allow a treatment of uppermost particles in the particle mass.

[0006] The invention provides the benefit that the particles are treated in an area of the particle mass wherein same is not yet built up such that tools do not have to cut open or pierce the particle mass. Thus, the arrangement of the particle mass, once built up, does not have to be rearranged, which could lower the stability of the particle based element or at least reduce the accuracy of the arrangement of first and second particles in the particle mass.

[0007] In a preferred embodiment, the first particles flow around the tools before reaching the upper part of the particle mass. The flow of the particles around the tools is in particular enabled by tools which have a generally convex upper side facing the flow of particles in the dispersing section. Thus, the tools do not significantly disturb the flow of particles before the particles reach the upper part of the particle mass.

[0008] The dispersing section is in particular a section, wherein a particle mass is formed by evenly distributing particles. Particularly, the particles are evenly distributed in a certain area and fall on the upper part of the particles mass by means of gravity.

[0009] In one embodiment, the second particles are treated by means of the tools, such that they have different properties than the first particles. In particular, they may be treated with fluid. For example, a treatment with water allows that the treated particles, i.e. the second particles, can be further compressed than the first particles in a subsequent compressing step, such that the second particles form areas of higher density in the particle based element. A treatment is also possible by means of energy, such as heat, or vapor. The particles may comprise additives, which interact with the treatment media, such as by building foam. Furthermore, the fluid, in particular the water, used for the treatment may comprise additives, which improve the interaction of the fluid with the particles. For example the fluid may comprise surface tension reducing additives, such as tensides. Furthermore, the insertion of fluid, in particular water, may improve the heat conduction in a later heating step, which may be carried out in particular during the compressing of the particle mass.

[0010] In another embodiment, the second particles are dispersed by means of the tools. Thus, initially only first particles are dispersed in the dispersing section, while tools disperse additional second particles, which are arranged in a predetermined pattern with respect to the first particles in the particle mass. The second particles may have different properties, in particular a different size, density, compressibility or may comprise different additives, or may have other properties which allow a different behavior during a later compressing or heating step.

[0011] Preferably, each of the tools is adapted to provide the second particles at predetermined time intervals, such that the predetermined pattern of the second particles in the particle mass is created. In particular, the second particles may be provided at predetermined discrete points in time. Thus, the second particles may be provided at predefined discrete locations in the particle mass. While the particle mass is moving with respect to the tools, different areas of the particle mass may be provided with second particles, such that the predetermined pattern of the second particles with respect to the first particles in the particle mass can be created.

[0012] In one embodiment, the tools are moving reciprocatingly along the upper part of the particle mass in the dispersing section. In particular, the tools are adapted to move less than a maximum distance defined by the distance in between the tools. Thus, the tools can provide the second particle at every desired location throughout the particle mass without the necessity that the tools move along long distances, as it is required in the prior art. The little movement of the tools enables that the unvoluntarily dislocation of particles by means of the tools is significantly reduced. Thus, a higher precision of the arrangement of the particles in the particle mass can be obtained.

[0013] In particular, the upper part of the particle mass is substantially a plane connecting the lowermost line of particles at the upstream end of the dispersing section and the uppermost line of particles at the downstream end of the dispersing section, wherein the lowermost line and the uppermost line extend in the width direction. This is due to the fact that throughout the dispersing section particles are substantially evenly distributed, and thus at the upstream end the initial, lowermost particles are dispersed, while at the downstream end the last, uppermost particles are dispersed. In between the upstream end and then the downstream end of the dispersing section the height of the particle mass is built up.

[0014] Preferably, the method comprises the subsequent step of compressing and bonding the particle mass to form a particle based element. The compressing may be carried out in two steps. In a first step the particle mass is compressed by means of a downwardly inclined conveyor which is arranged above the particle mass such that the height of the particle mass in between the conveyor on which it is arranged and the upper conveyor is reduced. Further, in a second step a continuous press compresses the particle mass and holds it in the compressed state for a certain time. In particular, during this continuous compression, the particle mass may be additionally heated. The heating enables in particular that the particles are bonded to each other. Preferably, resin, or other adhesive, is provided in the particle mass before the compression.

[0015] The invention also provides an apparatus for the production of a particle based element, in particular a particle board or fiber board, wherein the apparatus comprises a dispersing section in which particles are dispersed, and several tools for providing particles with different properties. According to invention, the tools are arranged in the dispersing section and at least one tool has a generally convex upper side facing the flow of particles in the dispersing section. This allows that the particles in the dispersing section flow smoothly around the tools and do not accumulate on the tools. Thus, the tools are not significantly disturbing the even distribution of the particles in the dispersing section. In particular, the particles are distributed in the dispersing section on a conveyor in a substantially even distribution, to form a particle mass. In particular, all tools have a generally convex upper side facing the flow of particles in the dispersing section.

[0016] Preferably, the tools are arranged in a spaced relationship substantially in the conveying direction above and along the upper part of the particle mass in the dispersing section. This allows that various regions of the particle mass can be provided with particles by means of the several tools.

[0017] In particular, the tools are arranged at different heights. This allows that different layers of the particle mass may be provided with particles with different properties. Alternatively, the tools may be arranged at different locations in the conveying direction above the upper part of the particle mass.

[0018] Preferably, the at least one tool has a treatment means at its lower side. The treatment means can, thus, treat the particles, which are arranged below the tool. In particular, the lower side of the tool is arranged along the upper part of the particle mass in the dispersing section or above the upper part of the particle mass in the dispersing section. Thus, the particles which are currently at the upper part of the particle mass can be treated or the particles which are currently falling down by means of gravity in the dispersing section can be treated.

[0019] Alternatively, instead of a treatment means, a particle dispersing means may be provided at the lower side of the tool, to provide particles with different properties.

[0020] In one embodiment, the two upper sides of the at least one tool adjacent to an upper edge of the tool have an acute angle with respect to each other at the upper edge. In particular, the acute angle allows that the particles flow smoothly around the tool. In particular, the two upper sides are adjacent to the uppermost edge of the tool. In one embodiment, the upstream side of the tool may be substantially vertical while the downstream side may have an angle in between 20° to 60°, preferably around 45° with respect to the upstream side. This enables that an acute angle is formed at the uppermost edge of the tool. Furthermore, this enables that the particles at the upstream side are not changed in the flow direction, while at the downstream side the particles are smoothly guided towards the downstream end of the tool.

[0021] In one embodiment, the lower side of the at least one tool is inclined in a downstream and downwards direction, such that it serves to precompress the upper part of the particle mass. Thus, each tool allows a precompression of the particle mass building up in the dispersing section, which enables that the precision of the particles in the particle mass is better defined.

[0022] In one embodiment, a particle provision device is arranged inside the at least one tool adapted to provide particles with different properties below a lower opening at the lower side of the tool. The particle provision device may be a treatment device which is adapted to treat the particle mass being arranged below the lower opening of the tool. The treatment device may in particular be a spraying device or a device for providing energy, such as a heater. Furthermore, the particle provision device may also be a dosage element for dispersing particles with different properties through the lower opening of the tool.

[0023] In the following, the invention will be described by means of exemplary embodiments of the invention, which are shown in the following figures.

Figure 1 shows a schematic side view of an apparatus according to an embodiment of the invention.

Figure 2 shows a schematic side view of the dispersing section of an apparatus according to one embodiment of the invention.

Figure 3 shows a schematic side view of the dispersing section of an apparatus according to an embodiment of the invention.

Figure 4 shows a tool for the apparatus according to Figure 3.

Figure 5 shows a tool for an apparatus according to an embodiment of the invention.

[0024] In Figure 1 an apparatus 1 according to an embodiment of the invention is shown. In the apparatus, first particles 2 are conveyed through first drums 3, in which they are prepared for their distribution. In particular, the first particles 2 are wood fibers and the first drums 3 enable that they can be evenly distributed. The first particles 2 are then evenly distributed by means of several second drums 4, such that the first particles 2 are evenly dispersed in a dispersing section 5. In particular, a conveyor belt 6 is arranged in the dispersing section and extends downstream of the dispersing section 5. The conveyor belt 6 moves the particles arranged thereon in a conveying direction C. Thus, due to continuous movement of the conveyor belt 6 and the even distribution of the first particles 2 in the dispersing section 5, a particle mass 7 in the form of a particle mat can be formed. In the dispersing section 5 the particle mass 7 slowly gains height in the height direction H due to the continuous provision of particles thereon. Thus, the upper part of the particle mass extends in the slightly upwards inclined direction T. The particle mass is substantially evenly distributed in the width direction W which is perpendicular to the drawing plane. The width direction W is in particular perpendicular to the conveying direction C and the height direction H. In the dispersing section 5 several tools 8 are arranged. The tools 8 serve the purpose of providing second particles 9, which have different properties from the first particles 2. The provision of second particles 9 by the tools 8 may either be enabled by treating the first particles 2, or by additionally inserting the second particles 9 in the particle mass 7. In particular, the tools 8 are arranged in a spaced relationship in the direction T along the upper part of the particle mass in the dispersing section 5. The tools have a generally convex upper side which is facing the flow of particles in the dispersing section. In particular, the tools 8 extend in the width direction W through the particle mass 7.

[0025] The length of the dispersing section in the conveying direction C is several times the height of the particle mass 7 in the height direction H. This is due to the fact that the particles in the dispersing section 5 are evenly distributed in a lower concentration than the concentration of the particles arranged in the particle mass 7. If the density of particles in the first area 10 of the dispersing section is increased, the tools preferably show a conelike form to open the dense flow of particles.

[0026] As can be seen in Figure 1, the second particles 9 are provided on top and on the bottom of the particle mass 7. Further the second particles 9 form a wavelike structure inside the particle mass 7. In particular, the wavelike structure extends from the bottom to the top of the formed particle mass 7. Thus, when the second particles have a higher compressibility than the first particles 2, after compression the density in the region of the second particles 9 will be higher. Alternatively, the second particles 9 may be particles with a higher strength. In both cases the stability of the produced particle based element, in particular a particle board, can be significantly increased, without a substantial increase in weight of the particle board.

[0027] Each of the tools 8 is adapted to provide the second particles at specific points in time. While the uppermost tool 8 and the lowermost tool 8 provide the second particles in a substantially continuous manner, the intermediate tools 8 only provide particles at specific points in time to form the desired predetermined pattern, in this case a wavelike structure, in the particle board.

[0028] In particular, the dispersing section 5 can be divided in two areas. In the first area 10 the particles are falling under the influence of gravity, while in the second area 11 the particles form a particle mass 7. The border in between the first area 10 and the second area 11 is the upper part 12 of the particle mass.

[0029] The tools 8 have a generally convex upper side that is composed of one substantially horizontal side at the uppermost edge of the tool and two inclined sides at the upstream and downstream side of the tool. However, it is also possible to provide strictly convex tools, which have in particular a convex curved upper side.

[0030] In Figure 2, an alternative position for one of the tools 8 is indicated by numeral 8'. The other tools 8 may also be arranged accordingly at a higher position. In particular, all tools may be arranged at the same height in a spaced relationship in the conveying direction in the area 10. While in Figure 1, all tools are arranged at the upper part of the particle mass in the dispersing section 5, the tools may also be arranged at a higher position within the first area 10 of the dispersing section. Thus, the tool 8' treats the falling first particles or provides additional second particles in between the falling first particles to obtain the predetermined arrangement of the first particles in the second particles.

[0031] In Figure 3, a further embodiment of an apparatus according to the invention is shown. In this embodiment, the tools 8 are formed by an upstream upper side 13 and a downstream upper side 14. The upper sides 13 and 14 are connected to each other at the upper edge of the tool 8 with an acute angle. Thus, the particles can easily flow around the tools 8. In particular, the upstream upper side 13 extends in a substantially vertical direction in the height direction H while the downstream upperside 14 is an inclined plane. Inside the tool 8, a particle provision device 15 is arranged, which treats the particles below a lower opening 16 of the tool. The particle provision device may either be a treatment device, which treats particles below the lower opening 16, or a particle dispersing device, which disperses additional second particles 9 on the first particles 2. In Figure 4, it can be seen that in two different areas below the lower opening 16 second particles 9 are provided by means of the particle provision tool 15, while the remaining shown particle mass 7 is comprised of first particles 2. However, it is also possible that the whole area below the lower opening 16 is provided with second particles 9.

[0032] In Figure 5, a tool according to a further embodiment of the invention is shown. The tool 8 comprises as well the upper sides 13 and 14, wherein the upstream upper side 13 is substantially vertical in the height direction, and the downstream upper side 14 is inclined. Further, the tool comprises a lower side 17, which is inclined in a downstream and downwards direction, such that it serves to precompress the upper part 12 of the particle mass 7. This can be seen in Figure 5, as the upstream particle mass 7 is higher than the downstream particle mass 7. Furthermore, on the lower side 17 of the tool 8 a particle provision device 15 is arranged. In this embodiment, the particle provision device 15 is arranged at the downstream end of the lower side 17. The particle provision device either provides additional second particles 9 to the particle mass comprised of first particles, or it treats the first particles 2, such that they turn into particles with different properties, namely second particles 9. The inclined lower side 17 as shown in Figure 5 allows that the particles are precompressed before they reach the particle provision device 15, in particular the particle treatment device. Thus, it can be guaranteed that the particles are already in the form of a slightly compressed particle mass, such that they remain in substantially the same position with respect to each other. Furthermore, the close contact of the particles and the treatment device enables a cleaning effect of the treatment device. If the density of particles at the treatment device would not be sufficiently high, treatment fluid could remain on the treatment device without being immediately picked up by the particles.

[0033] The tool 8 according to Figure 5 can be arranged substantially in the positions of the tools 8 as shown in Figure 2 or Figure 3. In particular, the tool 8 is arranged in a manner, such that its lower side 17 is provided at the height of the upper part 12 of the particle mass 7 in the dispersing section 5.

[0034] In the following, the method according to an embodiment of the invention is described with respect to Figure 1. First particles 2 are evenly distributed in a dispersing section 5 and are dispersed to form a particle mass on a conveyor 6, which continuously conveys the particle mass 7 in the dispersing section 5. Further, in the dispersing section 5 second particles 9 are arranged in a predetermined pattern with respect to the first particles 2, wherein the first and second particles 2,9 have different properties. Several tools 8, being arranged in a spaced relationship substantially in the conveying direction and along the upper part of the particle mass 7 provide the second particles 9 in the particle mass 7. The provision of the second particles in the particle mass may be effected either by treatment of the first particles 2 or by additionally inserting second particles 9.

[0035] The above described embodiments of the invention enable that a particle mass in a dispersing section can be treated or provided with additional different particles in horizontal layers in a dispersing section 5. Thus, various predetermined patterns of second particles 9 with different properties than first particles 2 can be provided in a particle mass 7. Generally, all 3D geometries for the second particle 9 pattern in the first particles 2 are possible. In particular, the second particles 9 form zones of higher stability, to improve the stability of the particle based element manufactured with the inventive apparatus or method. However, the second particles may also be particles which are lighter and less stable than the first particles. In this case the second particles 9 serve the purpose of lowering the weight of the particle based element, while the first particles 2 provide the stability of the particle based element.

[0036] The treatment of the first particles 2 may involve that foam is generated. In particular polyurethane foam can be injected into the first particles 2. Then the second particles 9 would refer to an area of particles, whereas the particles are mixed with polyurethane foam.

[0037] In all embodiments, the tools may be vibrated to enable a better flow of particles around the tools.

[0038] Treatment openings or particles dispersing openings may be provided all around the tools. Furthermore, tools can be provided which rotate, to enable that the particle provision devices treat various regions of the particle mass in the particle dispersing section.

[0039] Possible treatment fluids for the particle mass are water, adhesive, resin, or steam. Further, microcapsules may be injected in the particle mass. The application of fluid can be enabled by spraying, flowing, injecting, shooting, stamping, etc.

[0040] Preferably, the fluid is provided through individual openings in the tool. The openings are preferably in a distance to each other of about 5 mm. The tools may have a width of preferably 300 to 4000 mm, preferably around 2700 mm. The tools preferably have a height of about 15 mm to 200 mm and a length in the conveying direction of about 20 mm up to 200 mm. The treatment fluid may be provided to the tools from the side. Each of the openings of the tools may be controlled separately to release the treatment fluid. Furthermore, all treatment openings of each tool, respectively, may be controlled to open at the same time. The first alternative allows providing more complex patterns in the particle mass, while second alternative is more cost effective. The tools may be openable for small time intervals as low as 0.01 seconds. Preferably the tools may be openable for time intervals around 0.05 seconds. The fluid amount which is injected through one of the openings in the tool is around 0.1 mm per injection. In particular, only low pressure is required.

[0041] Measurement devices may be provided after the dispersing section to control the humidity, density and/or other properties of the particle mass 7.

[0042] At least one rotating element may be arranged on top of or above the at least one tool 8, to enable a smooth flow of particles around the tool 8. In particular, one rotating element may be arranged centrally above the tool, or two rotating elements with opposite rotation directions may be arranged next to each other above the tool. The rotation axis of the rotating element is preferably in the width direction. The rotating element may be a rotating drum. The rotating element may rotate around a centered or off-centered axis. The rotating element may rotate continuously or may rotate reciprocatingly around an angle less then 360°. In some embodiments the reciprocating rotation may be around such small angles that it can be considered a vibration of the rotating element.

Claims

1. Method for the production of a particle based element, in particular a particle board or fiber board, comprising:

dispersing particles in a dispersing section (5) to form a particle mass (7), while the particle mass (7) and the dispersing section (5) are moving relative to each other in a conveying direction (C),

such that second particles (9) are arranged in a predetermined pattern with respect to first particles (2) in the particle mass, the first and second particles (2,9) having different properties,

characterized by

providing the second particles (9) in the particle mass (7) by means of several tools (8) being arranged in a spaced relationship substantially in the conveying direction (C) in the dispersing section (5) above the upper part of the particle mass (7).

2. Method according to claim 1, wherein the first particles (2) flow around the tools (8) before reaching the upper part (12) of the particle mass (7).

3. Method according to claim 1 or 2, wherein the second particles (9) are treated by means of the tools (8), such that they have different properties than the first particles (2).

4. Method according to claim 1 or 2, wherein the second particles (9) are dispersed by means of the tools (8).

5. Method according to any one of the previous claims, wherein each of the tools (8) is adapted to provide the second particles (9) at predetermined time intervals, such that the predetermined pattern of second particles (9) in the particle mass (7) is created.

6. Method according to any one of the previous claims, wherein the tools (8) are moving reciprocatingly along the upper part (12) of the particle mass (7) in the dispersing section (5).

7. Method according to any one of the previous claims, wherein the upper part (12) of the particle mass (7) is substantially a plane connecting the lowermost line of particles at the upstream end of the dispersing section (5) and the uppermost line of particles at the downstream end of the dispersing section (5).

8. Method according to any one of the previous claims, comprising the subsequent step of compressing and bonding the particle mass (7) to form a particle based element.

9. Apparatus (1) for the production of a particle based element, in particular a particle board or fiber board, comprising:

a dispersing section (5) in which particles are dispersed, and

several tools (8) for providing particles (9) with different properties,

characterized in that

the tools (8) are arranged in the dispersing section (5) and at least one tool (8) has a generally convex upper side facing the flow of particles (2) in the dispersing section (5).

10. Apparatus according to claim 9, wherein the tools (8) are arranged in a spaced relationship substantially in the conveying direction (C) above and along the upper part of the particle mass (7) in the dispersing section (5).

11. Apparatus according to claim 9 or 10, wherein the tools (8) are arranged at different heights.

12. Apparatus according to any one of the previous claims 9 to 11, wherein the at least one tool (8) has a treatment means at its lower side.

13. Apparatus according to any one of the previous claims 9 to 12, wherein two upper sides (13,14) of the at least one tool (8) adjacent to an upper edge of the tool (8) have an acute angle with respect to each other at the upper edge.

14. Apparatus according to any one of the previous claims 9 to 13, wherein the lower side (17) of the at least one tool (8) is inclined in a downstream and downwards direction, such that it serves to precompress the upper part (12) of the particle mass.

15. Apparatus according to any one of the previous claims 9 to 14, wherein a particle provision device is arranged inside the at least one tool adapted to provide particles with different properties below a lower opening at the lower side of the tool.

Drawing