EP3774245B1 - Scattering process. - Google Patents

Description

The disclosure relates to a scattering device for producing a mat of grit on a scattering belt conveyor in the course of the production of wood-based panels, with at least one grit bunker and a scattering head arranged below the grit bunker and above the scattering belt conveyor, with the scattering head distributing several along the transport direction (of the scattering belt conveyor), (preferably (rotatingly driven) spreader rollers, which spread the material to be spread onto the spreader belt conveyor, with the spreader head having at least two spreader areas arranged one behind the other with different roller geometry and/or different roller modes of operation.

In the context of the disclosure, wood-based panels means in particular fiberboards (e.g. MDF panels), or chipboards or OSB panels. The grit is consequently lignocellulose-containing grit, in particular wood fibers, wood chips or wood strands (which are also referred to as coarse chips). Fine materials such as B. wood fibers or fine chips are preferably used in order to obtain a high quality of board surfaces with good properties in terms of coatability or paintability. Other materials such as B. long wood chips, strands or even non-woody layers are used to improve other properties such. B. Bending properties, shear properties, tensile properties, screw pull-out resistance, millability. Still other fractions are used to improve the economy in the manufacturing process and to use certain residual products in non-critical situations and not lose these fractions for added value. In this respect, it is known to produce wood-based panels in a multi-layer structure from different fractions and consequently from different grit.

The grit is preferably provided with a binding agent and is consequently in the form of glued grit. The (glued) grit is initially temporarily stored in the grit bunker, which serves as a material buffer and is preferably designed as a dosing bunker. For this purpose, the grit bunker preferably has a dosing unit, which z. B. is designed as a (driven) bunker floor belt. Furthermore, the bunker preferably has a discharge unit which, for. B. is designed as a discharge roller front. Finally, preferably, the discharge of the bunker is followed by a chute which, e.g. B. is arranged between grit bunker and scattering head, so that the material from the grit bunker passes through the chute to the scattering head. The scattering head scatters and distributes the material onto the scattering belt conveyor, on which a mat of grit is continuously built up during transport. This grit mat is - if necessary after further intermediate steps such. B. pre-pressing, leveling, moistening or the like - fed to a press in which the mat of grit is pressed using pressure and / or heat to form a wood-based panel. The press may be a continuous press, e.g. B. double belt press, or a cycle press, z. B. act single-daylight or multi-daylight press.

The scattering head of such a scattering device, which generally has a large number of scattering rollers arranged one behind the other in the longitudinal direction, is in practice usually structurally adapted to the material to be processed with the scattering head (e.g. either fibers or chips). On the one hand, this relates to the roll geometry, ie both the design and geometry of the individual rolls and the arrangement of the rolls relative to one another, e.g. B. their distances. Furthermore, this adjustment relates to the roll mode provided for in the spreader head, e.g. B. Direction of rotation and/or speed of the rollers. In this way, a targeted optimization of the spreader head for a specific type of material takes place in practice. Furthermore, the scattering heads are regarding Roller geometry and/or roller mode of operation set up for different directions of orientation, ie spreading heads are provided for longitudinal orientation of the spreading material on the one hand and transverse orientation of the spreading material on the other hand. Finally, the spreading heads are also set up for a special direction of separation of the spreading material (relative to the mat cross section), so that z. B. a separation is realized in such a way that coarser material is scattered to the core of the mat and finer material to the surface of the mat. The roller geometries (e.g. disc rollers, spiked rollers or the like) that are optimally suited for the various purposes are known in principle from practice.

If a plant for the production of wood-based panels is only equipped with a single scattering head or several identically designed scattering heads for several layers, the plant is usually only designed for one type of mat and thus also for one type of panel, so that there are only possible variations with regard to the product to be manufactured are very limited.

It has therefore already been proposed in practice to equip a production plant with several spreading heads arranged one behind the other, which are designed differently and optimized for different types of spreading material or plate types, so that only one of these spreading machines or a group of spreading machines is then used for a specific product. Although such a system can be used flexibly for different types of materials and panels, it is characterized by very high investment costs and a very long construction and therefore high space requirements. In addition, there is a correspondingly required material logistics for the variable loading of the individual spreading machines, so that such variable-use production systems have economic disadvantages.

Incidentally, from the DE 10 2016 109 987 A1 a scattering system for producing a mat of grit and a method for operating such a scattering system is known, in which the scattering head has at least one first feed area and at least one second feed area spaced from this in or against the production direction for feeding the grit and/or in which at least one, preferably all rollers of a roller arrangement are suitable for changing their direction of rotation. Consequently, the spreader head has differently configured roller areas which, for. B. for a different orientation, z. B. longitudinal orientation or transverse orientation are formed. The structure of the mat can be influenced by selecting an appropriate discharge opening and by selecting the direction of rotation of a dissolving device. So e.g. B. by selecting the output opening and selecting a direction of rotation of the rollers, either a fine chip fraction is initially deposited on the transverse orientation device and a coarse chip fraction is deposited on the longitudinal orientation device or, conversely, coarse chips are first deposited on the transverse orientation device and fine chips are deposited on the longitudinal orientation device. This makes it possible to influence the order of the layers and thus the layer structure when scattering the mat.

DE102007049947A1 discloses the subject-matter of the preamble of claim 1.

The disclosure is based on the object of creating a scattering device which, in a plant for the production of wood-based panels with a compact design and small space requirements, enables flexible production of different products, in particular using different types of material.

The invention is defined by the features of claim 1. The disclosed scattering device has a

• wobei der Streukopf zumindest zwei hintereinander angeordnete Streubereiche mit unterschiedlicher Walzengeometrie und/oder unterschiedlicher Walzenbetriebsweise aufweist,
• wobei zwischen Streugutbunker und Streukopf eine Umschalteinrichtung angeordnet ist, mit der der Streugutstrom aus dem Streugutbunker wahlweise auf entweder nur den ersten Streubereich oder nur den zweiten Streubereich des Streukopfes geleitet wird. Die Umschalteinrichtung ist folglich derart ausgebildet und derart einstellbar, dass stets nur einer der Streubereiche mit Material beschickt wird.

scattering material bunker and a scattering head arranged below the scattering material bunker and above the scattering belt conveyor, the scattering head having several scattering rollers distributed along the transport direction (of the scattering belt conveyor) (preferably arranged directly above the scattering belt conveyor), which scatter the scattering material (directly) onto the scattering belt conveyor which forms a grit mat,

• wherein the spreading head has at least two spreading areas arranged one behind the other with different roller geometries and/or different roller modes of operation,
• wherein a switching device is arranged between the grit bunker and the scattering head, with which the grit flow from the grit bunker is selectively directed to either only the first scattering area or only the second scattering area of the scattering head. The switching device is consequently designed and set in such a way that only one of the scattering areas is ever loaded with material.

The disclosure is based on the finding that a scattering device with (only a single) bunker for grit and (only a single) scattering head assigned to the bunker for grit can be used variably if a scattering head with two different scattering areas is made available, which can be switched via a switching device can be selected in a targeted manner, in such a way that only one of the areas that is optimally adapted to the desired properties of the material to be spread and/or the plate is fed, with the scattering area used being able to be selected very easily and quickly with the aid of a switching device , so that fast and flexible Adjustment of the spreader (also known as a spreader) is possible.

The two scattering areas are preferably characterized by different roller geometries. This means that different roller types and consequently rollers with different construction and/or geometry can be used in the two spreading areas, e.g. B. either spiked rollers or disc rollers. In addition, the different roll geometry z. B. also different arrangements of identical or different rolls, z. B. different roller distances, so that although identical types of rollers can be arranged in the two scattering areas, but in a different arrangement or with different distances. As an alternative or in addition, the two different scattering ranges can be differentiated by different roller modes of operation, i. H. they can basically have identical roll geometries, but the rolls can be operated with different modes of operation, e.g. B. different directions of rotation and / or different speeds. During operation, the two scattering areas always lead to different scattering results on the scattering belt conveyor.

In a particularly preferred embodiment, the two scattering areas of the scattering head are designed for different grit and consequently a different type of grit, e.g. B. for fine litter material (especially fibers, dust or chip cover layer material) on the one hand or coarse litter material (e.g. chips or strands) on the other. Such a scattering head is preferably assigned to a single grit bunker, which can be optionally filled with grit of different types. This means that different materials can be processed in a very compact manner with one and the same spreading machine. One and the same grit bunker can be used - depending on required - fill with different material and accordingly use the switching device to select the spreading area of the spreading head that is optimally adapted to this spreading material. This aspect is of particular interest in systems in which several spreading devices (spreading machines) are arranged one behind the other along the transport direction of the spreading belt conveyor in order to produce multi-layer mats of spreading material. In practice, there is a need to produce grit mats from several layers, which consist of different materials or different fractions, e.g. B. fine material for a top layer and coarse material for a middle layer. Unless several of the disclosed

Because the spreading devices are arranged one behind the other, the individual spreading machine can be selected for a specific type of material (i.e. a specific fraction) by selective filling of the individual bunkers and selection of the respective spreading areas, and thus then adapted to the desired product.

In principle, however, the disclosure also includes embodiments in which a corresponding scattering area is selected with one and the same scattering material in the scattering material bunker in order to orientate and/or separate the scattering material in different ways. So e.g. B. be formed a scattering area for a longitudinal orientation and the other scattering area for a transverse orientation of the grit, z. B. by appropriate roller construction, ie on the one hand rollers for a longitudinal orientation and on the other hand rollers for a transverse orientation. Such roller types are known in principle from the prior art. In addition, it is known to provide a certain fractional separation in spreading heads by means of the roll geometry and/or the roll mode of operation, e.g. B. in a certain direction initially finer material then coarser material arrives on the scatter belt conveyor to the layer structure influence. In one possible embodiment, the first scattering area can be designed for one type of fraction separation and the second scattering area for another type of fraction separation (e.g. in the opposite direction), so that depending on the selection of the scattering area, a different fraction separation is realized in relation to the mat cross section . Always only one of the scattering areas of the scattering head is used, which is optimally suited for the specific purpose.

The selection of the spreading area is made via a switching device, which is arranged between the spreading material bunker and the spreading head. The material from the grit bunker always arrives in the same way in the area of this switching device, which can, however, be constructed in different ways. The switching device can be arranged completely or partially within the above-mentioned chute between the grit bunker and the spreading head.

In a first embodiment, the switching device has at least one adjustable guide element, e.g. B. an adjustable switching flap. It can be e.g. B. be a switching flap which is pivotable about a pivot axis which is oriented parallel to the roller axes of the rollers of the spreading head, wherein the pivot axis is preferably arranged at the lower end of the switching flap.

In a second embodiment, the switchover device can have a roller device or be designed as a roller device that has a plurality of switchover rollers that can be switched over in their direction of rotation. All of the material from the grit bunker can therefore reach these switchover rollers and, depending on the direction of rotation, promote them Switchover rollers the material onto either the first spread area or the second spread area of the spreader head. This embodiment can also be combined with the above-mentioned changeover flap or the adjustable guide element, so that the changeover device has an adjustable guide element on the one hand and a roller device on the other hand, with the adjustable guide element preferably being arranged above the roller device.

In the third embodiment, the switching device can have not only a single switching valve, but several adjustable guide elements, so that these guide elements z. B. form a variable product constriction in the chute within the chute. This product constriction z. B. be combined with an additional roller device as a switching device.

In all three embodiments or combinations of these three embodiments, the switching device can also have a stationary guide element, e.g. B. have a wedge or the like, which clearly separates the two scattering areas of the scattering head from each other, so that actually only one of the two scattering areas is charged.

As already mentioned, several scattering devices or scattering machines are often combined with one another in a production plant for the production of wood-based panels, e.g. B. arranged one behind the other along the transport direction of the conveyor belt. The disclosure consequently also relates to a scattering system which has a plurality of the described scattering devices which are arranged one behind the other along the transport direction of the scattering belt conveyor and which are optionally oriented in opposite directions to one another. However, all scattering devices of such a scattering system scatter in the Rule on one and the same scatter belt (or scatter belt conveyor), so that the scattering devices are arranged along the same scatter belt conveyor.

The invention relates to a method for producing a grit mat with a scattering device of the type described or with a scattering system (consisting of several scattering devices) of the type described, with the switching device arranged between the grit bunker and the scattering head, the flow of grit from the grit bunker being selectively directed to only the first scattering area or only the second scattering area of the scattering head is conducted. The operation of such a system is therefore also protected.

According to the invention, the grit bunker is optionally filled with grit of different types. With that, e.g. B. different material types, z. B. meant either fiber or chips or different material fractions, z. B. fibers of different sizes or chips of different sizes. Depending on the grit contained in the grit bunker, the grit bunker is then selectively routed from the grit bunker to either only the first scattering area or only the second scattering area of the scattering head with the switching device, so that the grit is either fed via the first scattering area or the second scattering area to the Scatter belt conveyor arrives, the two scattering areas are each optimally adapted to the respective grit. With the same bunker filling or the same material type, there is the option of directing the material to one of the two spreading areas, which are set up for different orientation directions of the spreading material and/or for different separation directions of the spreading material, so that the material - depending on the selection of the spreading area - is oriented differently and/or is separated differently.

Overall, within the scope of the invention, an economic adaptation to the increased requirements and in particular the desire for flexibility in the wood-based panel industry is achieved. The disclosure may respond to the need to provide equipment that uses different material in different layers to achieve appropriate properties and economies for specific products. In terms of diversification, we can react quickly and flexibly, so that different products can be offered in smaller batch sizes economically and as required, even taking into account the increasing competition. This is achieved with little investment in terms of system technology.

Fig. 1

eine Streuanlage mit zwei Streuvorrichtungen (Streumaschinen) in einer ersten Ausführungsform,

Fig. 2

den Gegenstand nach Fig. 1 nach einer abgewandelten zweiten Ausführungsform und

Fig. 3

den Gegenstand nach Fig. 1 in einer dritten Ausführungsform.

The disclosure is explained in more detail below with reference to drawings that merely show exemplary embodiments. Show it

1

a spreading system with two spreading devices (spreading machines) in a first embodiment,

2

the object 1 according to a modified second embodiment and

3

the object 1 in a third embodiment.

In each of the figures, a scattering system is shown, which has two scattering devices 1 arranged one behind the other along the transport direction T of a scattering belt conveyor 2, which are also referred to as scattering machines. Each of these scattering devices 1 has a grit hopper 3 and a scattering head 4 arranged below the grit bunker 3 and above the scattering belt conveyor 2, the scattering head 4 several along the Transport direction T of the scatter belt conveyor 1 distributed, immediately above the scatter belt conveyor 2 arranged spreading rollers 5, which sprinkle the grit directly onto the scatter belt conveyor 2. The grit bunker 3 takes the grit (e.g. fibers or chips) as a material buffer and delivers it to the scattering head 4 . For this purpose, the grit bunker is preferably designed as a dosing bunker with a dosing unit 6, which is designed as a bunker floor belt in the exemplary embodiment. In addition, the grit bunker 3 has a discharge unit that is only indicated, the z. B. is designed as a discharge roller front 7. A chute 8 is arranged between the grit hopper 3 and the scattering head 4, so that the material reaches the scattering head 4 via the discharge roller front 7 of the grit bunker 3 and the chute 8, and from there it reaches the scattering belt conveyor 2, so that a grit mat is formed on the scattering belt conveyor 2 . In the exemplary embodiment shown, the system has two spreading machines 1 in order to realize a multi-layer structure of the mat of spreading material, ie the two spreading machines 1 are assigned to one and the same spreading belt conveyor 2 .

It is now provided that the spreading head 4 of the spreading machine 1 has at least two spreading areas 4a, 4b arranged one behind the other with different roller geometries and/or different roller modes of operation. A switching device 10 is arranged between grit hopper 3 and scattering head 4, with which the grit flow from grit bunker 3 can be directed either to only the first scattering area 4a or only to the second scattering area 4b of scattering head 4, so that with the aid of the switching device 10 it is possible to always only one of the scattering areas 4a, 4b is charged. In this way, a variable adjustment of the spreader 1 to the desired conditions, z. B. to the material used, to the desired direction of orientation of the material and / or to the desired fraction separation (based on the cross-section of the mat).

1 shows a first embodiment in which the switching device 10 has an adjustable guide element 11 which is designed as an adjustable switching flap 11, this switching flap 11 being pivotable about a pivot axis which is oriented parallel to the axis of the rollers 5 of the spreading head 4. It can be seen that by switching over the switching flap 11 either the first spreading area 4a or the second spreading area 4b of the respective spreading head 4 can be charged.

In this way, it is possible to optimize the first scattering area 4a and the second scattering area 4b for different types of material, so that z. B. the first scattering area 4a is optimized for fibers and the second scattering area 4b for chips or strands. In a preferred embodiment, the grit bunker 3 of a scattering device 1 is now optionally filled with either a first type of material (e.g. fibers) or a second type of material (e.g. chips) or with different fraction sizes of a material and the switching device 10 is then used the scattering range is selected which is optimally suited for the type of material arranged in the bunker 3. In this way, the spreading machine 1 can be variably adapted to different types of material and thus also to different types of panels, so that different types of panels can be pressed with one and the same system. In this embodiment it is indicated that within a scattering area 4a or 4b different scattering rollers 5 can be used, ie the first scattering area 4a or the second scattering area 4b can in turn be subdivided into further scattering areas. Regardless of the type of material used, the two different scattering areas can also be adapted for different scattering characteristics. B. the first scattering area 4a for a certain type of orientation (e.g. longitudinal orientation or Transverse orientation) and/or be designed for a different fraction separation. In 1 An exemplary embodiment is indicated in which the first scattering area 4a for fibers is formed without separation but with a fractional separation, in which the fine material is arranged closer to the product surface and the coarse material is arranged closer to the core of the plate. In contrast, the second scattering area 4b is optimized for chips, but also without orientation and in this case also without separation.

2 shows a modified embodiment in which the switching device 10 has a roller device 12 with a plurality of switching rollers 13 that can be switched in terms of their direction of rotation. In addition, in this embodiment, the already in 1 mentioned switching flap 11 is provided, but in principle a switching device 10 can also be realized without a switching flap and only with switching rollers. It is indicated that the switching rollers 13 are reversible. These are acceleration rollers with a reversible direction of rotation, so that the respective spreading area 4a, 4b can be selected by selecting the direction of rotation, in the exemplary embodiment combined with the switching flap 11.

3 shows an embodiment in which, on the one hand, a switching device 10 with switching rollers 13 is provided and, in addition, several adjustable guide elements 14 are arranged above the switching rollers 13, which form a variable product constriction in the chute 8. In this embodiment, the roller plane of the switching device 10 can also have a distribution function in addition to the switching function. For this purpose, distribution rollers can follow the switching rollers 13 (eg in one direction).

Incidentally, in the Figures 1 to 3 shown that the switching device 10 also has a stationary guide element 15, z. B. can have a wedge that separates the two scattering areas 4a, 4b from one another, so that overall it is ensured that actually only one of the scattering areas is charged.

In connection with the 1 the possibility that different material is processed with the scattering areas 4a, 4b has already been mentioned as an example. Optionally, there is the possibility, e.g. B. to work with the same type of material, z. B. with strands (OSB strands), which should be separated differently. So e.g. B. the first scattering area 4a for strands and for a longitudinal orientation, but be designed for a first specific separation direction, in which the coarse material is closer to the product surface and the fine material is closer to the core of the plate. The second scattering area 4b can also be designed for strands and for a longitudinal orientation, but with a reverse separation, in which the fine material is arranged closer to the product surface and the coarse material is arranged closer to the plate core. This is exemplary with the embodiment shown in FIG 2 feasible.

There is also the option of working with the same type of material but with a different orientation of the material. So e.g. B. the same type of material (z. B. strands for OSB boards) in the first scattering area 4a oriented transversely and oriented longitudinally in the second scattering area 4b. Alternatively or additionally, a different separation can also be implemented in the two scattering areas. This option is e.g. B. with the embodiment 3 possible.

Overall, very different embodiments can be realized, in which the scattering areas for different material types and/or for different orientation directions and/or for different fraction separations are formed in different combinations.

Otherwise, only two spreading machines 1 of such a system are indicated in the figures. However, it is also possible that further spreading machines 1 are provided, e.g. B. each left and right another spreader. Then the spreaders shown z. B. intended for the creation of intermediate or middle layers and the two left and right arranged spreading machines for top layers or optionally other intermediate layers. However, the serial arrangement of several such spreaders is known from the prior art. In the foreground of the disclosure is the variable adjustment of a single spreading machine to different product types.

Claims (12)

1. A method for producing a scattered particle mat on a scattering conveyor belt (2) in the course of manufacturing wood material boards,

   with a scattering device that comprises at least one scattering particle silo (3) and a scattering head (4), which is arranged underneath the scattering particle silo (3) and above the scattering conveyor belt (2),

   wherein the scattering head (4) has multiple scattering rollers (5) that are distributed along the transport direction (T) and scatter the scattering particles on the scattering conveyor belt (2),

   wherein the scattering head (4) has at least two scattering regions (4a, 4b) that are arranged behind one another and respectively have a different roller geometry and/or a different roller operating mode,

   and wherein a switching device (10) is arranged between the scattering particle silo (3) and the scattering head (4) and the scattering particle flow out of the scattering particle silo (3) is selectively conveyed to either only the first scattering region (4a) or only the second scattering region (4b) of the scattering head (4) by means of said switching device,

   characterized in that the scattering particle silo (3) is selectively filled with different types of scattering particles,

   and in that the scattering particle flow out of the scattering particle silo (3) is selectively conveyed to either only the first scattering region (4a) or only the second scattering region (4b) of the scattering head (4) by means of the switching device (10) in dependence on the scattering particles contained in the scattering particle silo (3).
2. The method according to claim 1, characterized in that the switching device (10) used has at least one adjustable guide element (11).
3. The method according to claim 2, characterized in that an adjustable switching flap is used as adjustable guide element (11).
4. The method according to one of claims 1 to 3, characterized in that the switching device (10) used has at least one roller device (12) with multiple switching rollers (13), the rotating direction of which is reversible.
5. The method according to one of claims 1 to 4, characterized in that the switching device (10) used has multiple adjustable guide elements (14) that form a variable material constriction, e.g. within a drop shaft (8).
6. The method according to one of claims 1 to 5, characterized in that the switching device (10) used has at least one stationary guide element (15), e.g. a wedge or the like.
7. The method according to one of claims 1 to 6, characterized in that a drop shaft (8) is arranged between the scattering particle silo (3) and the scattering head (4), wherein the switching device (10) preferably is arranged at least sectionally within the drop shaft (8).
8. The method according to one of claims 1 to 7, characterized in that the two scattering regions (4a, 4b), e.g. their roller geometries, are designed for different orientations of the scattering particles, e.g. for a longitudinal orientation of the scattering particles on the one hand and a transverse orientation of the scattering particles on the other hand.
9. The method according to one of claims 1 to 8, characterized in that the two scattering regions (4a, 4b), e.g. their roller geometries and/or roller operating modes, are designed for different separating directions of the scattering particles referred to the mat cross section.
10. The method according to one of claims 1 to 9, characterized in that the two scattering regions (4a, 4b), e.g. their roller geometries, are designed for different scattering particles, e.g. for fibers on the one hand and for chips or strands on the other hand.
11. The method according to one of claims 1 to 10, characterized in that a scattering system with two scattering devices for producing multilayer scattered particle mats is used, wherein the two scattering devices (1) are arranged behind one another along the transport direction (T) of the scattering conveyor belt (2).
12. The method according to one of claims 1 to 11, characterized in that the scattering particles are selectively conveyed to one of the two scattering regions (4a, 4b), which are designed for different scattering particles or different types of scattering particles and/or designed for different orientations of the scattering particles and/or designed for different separating directions of the scattering particles referred to the mat cross section.

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