EP0400359B1 - Method and device for the production of a coherent fleece of long fibres subsequently pressed into blocks or similar articles - Google Patents

Abstract

The invention relates to a process and to a device for producing a coherent web from long slivers which are produced by breaking-up the raw material fed and are then compacted to give a web which is subsequently glued and then pressed together with other webs to give blocks or the like. The raw material used is sticks or slabs which are split parallel to the fibers by vertically oscillating cutting motions, to give long slivers which are then compacted by ramming to give a web.

Description

The invention relates to a method and an apparatus for producing a coherent nonwoven from long splinters, which are produced by disassembling the supplied starting material and then compressed to form a nonwoven, which is subsequently glued and together with other nonwovens into blocks or the like. is pressed.

A corresponding method and devices for carrying out the method can be found, for example, in DE-OS 27 16 748. The aim here is to create a compressed wood product which, in contrast to conventional chipboard, is composed of elongated chips, which are arranged largely parallel to each other. Natural wood is used as the starting material, which is impacted by squeeze rollers in such a way that the wood is broken down parallel to the fibers to form a still-connected nonwoven. To support this crushing resolution, longitudinal notches or the like can be inserted into the natural wood from above. be introduced.

The production of such squeeze wood was described for the first time in Holz-Zentralblatt, Stuttgart, No. 11 of January 25, 1967 (essay "Squeeze wood - a new raw material for the pulp industry"). Other publications relating to this product are PCT-WO 85/02366, WO 85/02367, WO 85/02368, WO 85/02369 and WO 85/02370. US Pat. No. 3,674,219 still appears comparable.

The pinch of the wood common to this prior art for loosening its fiber composite and producing a mat from wood fiber sections which are still firmly connected to one another appears to be disadvantageous in several respects, but above all requires a very high expenditure of energy.

The invention has for its object to develop an improved method and an improved device for producing the nonwovens described above.

• a) Als Ausgangsmaterial werden Spreißel oder Schwarten verwendet, die neben- und übereinander angenähert parallel zueinander in Längsrichtung ausgerichtet und zu einem endlosen Paketstrang angenähert gleicher Breite und Höhe egalisiert werden;
• b) dieser Paketstrang wird in Längsrichtung der Spreißel oder Schwarten angenähert horizontal vorgefördert und dabei von oben mit Druckkräften beaufschlagt, um ein Ausweichen bei der nachfolgenden Zerlegung zu verhindern;
• c) der Paketstrang wird anschließend durch eine Zerlegungsvorrichtung hindurchgeführt, in der die einzelnen Spreißel oder Schwarten in Längsrichtung durch lotrechte Schnittbewegungen in kurzer Taktfolge in einzelne, faserparallel voneinander getrennte Langsplitter gespalten werden, wobei der Paketstrang an Höhe abnimmt, an Breite jedoch zunimmt;
• d) diese Langsplitter werden anschließend durch von oben auf sie einwirkende Stampfung zu einem Vlies verdichtet.

With regard to the process, this task is solved by the following process steps:

• a) As a starting material, chisels or rinds are used, which are aligned side by side and one above the other, approximately parallel to each other in the longitudinal direction and leveled to form an endless package strand of approximately the same width and height;
• b) this bundle of parcels is conveyed approximately horizontally in the longitudinal direction of the splitters or rinds and in the process is subjected to pressure forces from above in order to prevent evasion during the subsequent dismantling;
• c) the parcel strand is then passed through a disassembling device in which the individual splitters or rinds are split in the longitudinal direction by perpendicular cutting movements in a short cycle into individual longitudinal splinters which are separated from one another in a fiber-parallel manner, the parcel strand decreasing in height but increasing in width;
• d) these long fragments are then compressed to form a fleece by tamping acting on them from above.

According to the invention, no solid wood is used as the starting material, but rather chisels and rinds if necessary. Whereas prior art debarking of the starting material is required, this is not necessary according to the invention. According to the invention, the energy-consuming squeezing process is replaced by a fiber-parallel splitting process. Contrary to the previously known methods, the fiber composite is not only loosened according to the invention to a mat in which the fiber sections are still firmly connected, but the stacked starting material is split into individual, that is to say completely separate, longitudinal splinters, the cross sections of which are preferably on average 100 mm², but maximum Should be 200 mm². One speaks of "cutting movements"; however, these should be carried out in connection with the preferably continuous feed of the parcel strand in such a way that a splitting process results in the wood material, that is to say an air gap precedes the knife edge in the wood.

Before they are processed, the splinters or rinds can be combined into individual bundles in the sawmill and separated from these bundles to form the endless bundle of packages. It is useful if the package strand is at a height is equalized, which is considerably smaller than the diameter of a collar.

On their way between the individual cutting processes, the splinters or rinds are acted upon from above with their compressive forces in order to compress the starting material, which is stacked on top of one another, during its longitudinal decomposition.
Due to the longitudinal division of the splitters or rinds as a result of the repeated longitudinal splitting, internal tensions in the wood are released and lead to a fabric-like mat formed from loose longitudinal fragments lying next to or on top of one another. This mat-like structure is then compressed into a fleece by the tamping provided according to the invention. The pressure of the tamper can be adjusted so that the fiber composite can be loosened in a preselectable manner, which cannot be achieved with squeeze rollers.

In order to intensify the mutual felting of the long splinters during the formation of the fabric, it can be advantageous if the long splinters are guided on paths crossing at an acute angle. This further supports the spreading effect which already results from the longitudinal splitting, in which the longitudinal splinters formed from a splitter are slightly deflected from the original conveying direction on both sides by the splitting knife, which divides them lengthwise, so that subsequently there is a different direction course.

In principle, it would be possible to perform longitudinal splitting in a short cycle with splitting knives, the cutting edges of which are aligned horizontally and parallel to the fibers. However, longitudinal gaps, which are carried out with perpendicularly oscillating cutting movements of splitting knives, the cutting edges of which are at least approximately perpendicular, have proven to be advantageous, but in particular energy-saving, so that the splitting is carried out against the direction of the wood advance.

A particular advantage of the method according to the invention is that it does not process logs, but chisels and possibly rinds, which can normally be stacked on top of each other in several layers. In this case, raw material of any length can be used, while cut logs are required in the prior art. It is also advantageous that the process according to the invention can be used with controllable feed and cutting forces. According to the invention, the connection of the individual longitudinal splinters produced beforehand to form a transportable, continuous fleece takes place exclusively by pressurization. Any bark is separated or crumbled during the longitudinal cutting of the splinters or rinds and can therefore be easily removed.

If the splitters or rinds are combined in bundles before they are processed, it is advantageous if the bundle of strands is then leveled to a height that is considerably smaller than the diameter of a bundle.

According to the invention, the oscillation of the cutting movements for producing the long splinters can be up to 80 Hz. For the subsequent formation of the nonwoven, it is advantageous if the tamping acting on the long splinters or the braid to compress them from above exerts a sudden, sudden, high force effect, with a stored energy being converted in the range of milliseconds without large kinetic energies being developed have to. The fleece pressed in this way can then be subjected to thickness equalization. The parcel strand or the braid can be fed continuously at the same speed. As a result, a material jam combined with a compression of the longitudinal splinters, which burst open like a needle under this force, is achieved, inter alia, before the discontinuous stamping. This improves the matting, the effect mentioned being controllable.

• a) Ein Förderer für einen endlosen, aus längs ausgerichteten Spreißeln oder Schwarten bestehenden Paketstrang;
• b) eine oberhalb diese Förderers angeordnete, sich über die Förderbreite erstreckende und lotrecht nach unten wirkende, auf dem Paketstrang abrollende Druckvorrichtung;
• c) eine dem Förderer nachgeschaltete Zerlegungsvorrichtung, bestehend aus mehreren, quer zur Förderrichtung ausgerichteten, hintereinander und zueinander versetzt angeordneten Messerreihen, die sich jeweils aus mehreren, in lichtem Abstand nebeneinander angeordneten Spaltmessern zusammensetzen, die lotrecht verschiebbar geführt sind und einem Antrieb mit kurzer Taktfolge unterliegen;
• d) der Zerlegungsvorrichtung ist eine Verdichtungseinrichtung nachgeschaltet, in der die zuvor gespaltenen Langsplitter zu einem Vlies verdichtet werden.

The object on which the invention is based is achieved with regard to the device by the following features:

• a) A conveyor for an endless package strand consisting of longitudinally oriented splitters or rinds;
• b) a printing device which is arranged above this conveyor, extends across the conveyor width and acts vertically downwards, and rolls on the package strand;
• c) a dismantling device connected downstream of the conveyor, consisting of a plurality of rows of knives aligned transversely to the conveying direction, one behind the other and offset from one another, each of which is composed of a plurality of splitting knives which are arranged next to one another at a short distance from one another and are guided vertically displaceably and are subject to a drive with a short cycle ;
• d) the dismantling device is followed by a compacting device in which the previously split long fragments are compacted to form a fleece.

It may also be advantageous if guide elements for deflecting the longitudinally split splinters or rinds or elongated splinters are arranged within the dismantling device over their increasing conveying width in such a way that guide paths intersecting at an acute angle are formed for them.

A metering device can be connected upstream of the parcel strand conveyor to separate the splitters or rinds from bundles supplied. The pressure device upstream of the disassembly device can preferably pressure rollers and / or pressure balls have, which can be actuated via interconnected hydraulic cylinders, the pressure rollers are preferably floating. This results in an optimal adaptation of the printing device to the surface contour of the package strand.

In order to improve or ensure the parallel guidance of the splinters or rinds, the pressure device upstream of the disassembly device can have pressers with guide webs.

In order to avoid wedging of the splinters or rinds between the splitting knives, it is advantageous if the distance between the cutting edges of two splitting knives arranged in a row next to one another is smaller than between the rear knife edges.

The pressure devices provided in the disassembly device can also comprise floating, freely rotating pressure rollers. So that the vertically arranged splitting knives do not pull up the respectively applied splinters or rinds during their stroke movement, it can be expedient if the splitting knives are arranged inclined against the conveying direction and thereby enclose an acute angle with the latter.

The compression device downstream of the disassembly device can be composed of several force units, which convert the energy stored in them in a rapid cycle in the range of milliseconds. It is expedient if force units such as those used in German are used both for the oscillating drive of the splitting knife and for the drive of the compression device Patent specification 26 00 948 are described.

Further features of the invention are the subject of the dependent claims and are explained in more detail with further advantages of the invention on the basis of exemplary embodiments.

• Figur 1 in Seitenansicht eine Anlage zur Herstellung eines Vlieses aus Langsplittern;
• Figur 2 in vergrößertem Maßstab einen Anlagenabschnitt gemäß Figur 1 in Draufsicht und zum Teil im Horizontalschnitt;
• Figur 3 in gegenüber der Figur 1 vergrößertem Maßstab eine Druckvorrichtung in Stirnansicht und zum Teil im Querschnitt;
• Figur 4 ein Detail der Figur 2 in vergrößertem Maßstab und in abgewandelter Ausführungsform und
• Figur 5 in gegenüber Figur 1 vergrößertem Maßstab ein Detail der Figur 1 in abgewandelter Ausführungsform.

Some exemplary embodiments of the invention are shown schematically in the drawing. Show it:

• Figure 1 is a side view of a plant for producing a nonwoven from long splinters;
• Figure 2 on an enlarged scale a plant section according to Figure 1 in plan view and partly in horizontal section;
• Figure 3 on an enlarged scale compared to Figure 1, a printing device in front view and partly in cross section;
• Figure 4 shows a detail of Figure 2 on an enlarged scale and in a modified embodiment and
• Figure 5 on a larger scale than Figure 1 shows a detail of Figure 1 in a modified embodiment.

The system shown in FIG. 1 begins with a conveyor 1 for an endless parcel strand 2 consisting of longitudinally aligned splitters or rinds. Above the conveyor 1 there is a pressure device 3 which extends across the conveying width and acts vertically downwards and which forms the top of the parcel strand 2 acted upon and rolls on this. Figure 3 shows a presser 4 of this printing device 3, the pressure rollers 5 and / or pressure balls and guide webs 6 for better parallel guidance of the splinter 7 or rinds.

Downstream of the printing device 3 is a disassembly device 8, which has a plurality of rows of knives 10 which are aligned transversely to the conveying direction 9 and which are arranged one behind the other and offset from one another, each of which is composed of a plurality of splitting knives 11 arranged next to one another at a small spacing with the bundle strand 2 of opposing vertical cutting edges 12. The splitting knives 11 are guided such that they can be moved vertically and are subject to an oscillating drive 13. At least the splitting knives 11 of a row of knives 10 are arranged in a common gate 14 (see FIG. 5) which is acted upon by the oscillating drive 13 (not shown in more detail). The conveyor that transports the parcel strand 2 through the dismantling device 8 is formed by driven chains 15, which are passed between the splitting knives 11 and are arranged in an interleaved manner. In the disassembling device 8, pressing devices 16 are arranged between the individual rows of knives 10, which in turn may have pressure rollers and / or pressure balls and firmly compress the package strand 2 from above on the way through the disassembling device 8.

The disassembly device 8 is followed by a compression device 17, in which the previously split long splinters are compressed into a fleece 18. The disassembly device 8 is followed by a plate belt 19 as a conveyor for the fleece 18. A leveling roller 20 is arranged downstream of the compacting device 17.

FIG. 2 shows the area of the dismantling device 8, the pressing devices 16 provided between the rows of knives 10 not being shown for reasons of better clarity. In the area of this disassembly device 8 (and subsequently in the area of the compacting device 17 and the leveling roller 20), however, the package strand 2 increases in height and in width. The dismantling device 8 is preceded by a leveling roller 21 and the compression device 17 composed of several force units 17a is connected downstream. Guide elements 22 for deflecting the longitudinally split splinters or rinds or longitudinal splinters are arranged within the dismantling device 8 over their increasing conveying width in such a way that guide paths 23 which intersect at an acute angle are formed for them.

FIG. 4 shows that the distance a between the cutting edges 12 of two gap knives 11 arranged side by side in a row 10 is smaller than between the rear knife edges. The thickness of the knives 11 designed with a sharp cutting edge 12 is preferably 2-3 mm. The knife stroke can be around 200 mm.

The splitters or rinds used as the starting material are aligned side by side and one above the other, approximately parallel to one another in the longitudinal direction and equalized to form the endless package strand 2 of approximately the same width and height. This parcel strand, which is conveyed continuously or discontinuously on the conveyor 1, is acted upon by the printing device 3 in order to prevent evasion during the subsequent dismantling. The chain strand 2 is then transported by the disassembling device 8 in the conveying direction 9 from the chain conveyor 15. At the end, the packet strand 2 comes into the range of action of the splitting knives 11 which perform vertical oscillating cutting movements and which, with their vertical cutting edges 12, split the splinters or rinds in the longitudinal direction against their feed direction 9, longitudinal splits resulting from the repeated longitudinal splitting and being separated in parallel with the fibers. In order to intensify their matting, the guide elements 22 indicated in FIG. 2 are provided. By arranging the above Guide paths 23 ensure that the long fragments cross on their way through the separating device 8 and thus form a fabric, which is then compressed by the downstream compression device 17, which exerts a pounding on the fabric from above, to form the fleece 18 in which the long splinters are arranged predominantly in their longitudinal direction.

Claims (30)

1. Process for producing a coherent web from long slivers which are produced by breaking up the raw material fed and are then compacted to give a web which is subsequently glued and then pressed together with other webs to give blocks or the like, characterised by the following process steps:

   a) the raw material used is sticks or slabs which are aligned approximately parallel to each other in the longitudinal direction side by side and in superposition and are dressed to give a continuous packet strand of approximately equal width and height;

   b) this packet strand is advanced approximately horizontally in the longitudinal direction of the sticks or slabs and at the same time subjected to pressure forces from above, in order to prevent yielding during the subsequent breaking-up;

   c) the packet strand is then passed through a breaking-up device in which the individual sticks or slabs are split in the longitudinal direction by vertical cutting motions in a short time cycle to give individual long slivers which are mutually separate parallel to the fibres, the packet strand decreasing in height but increasing in width;

   d) these long slivers are then compacted into a web by ramming which acts on them from above.
2. Process according to claim 1, characterised in that the long slivers are moved on paths crossing at acute angles to form a mesh.
3. Process according to claim 1 or 2, characterised in that long slivers are produced having a cross-section of on average 100 mm², at most 200 mm².
4. Process according to claim 1, 2 or 3, characterised in that the individual sticks or slabs are split into long slivers against their direction of advance by vertically oscillating cutting motions.
5. Process according to one of the preceding claims, characterised in that, before they are processed, the sticks or slabs are combined into individual bundles and detached from these bundles to form the continuous packet strand.
6. Process according to claim 5, characterised in that the packet strand is dressed to a height which is considerably smaller than the diameter of a bundle.
7. Process according to one of the preceding claims, characterised in that the packet strand or its sticks or slabs are subjected successively to a plurality of vertically oscillating cutting motions.
8. Process according to one of the preceding claims, characterised in that the oscillation of the cutting motions amounts to up to 80 Hz.
9. Process according to claim 7 or 8, characterised in that the sticks or slabs are subjected from above to pressure forces promoting the advance of said sticks or slabs when said sticks or slabs are being passed between the individual cutting operations.
10. Process according to one of the preceding claims, characterised in that the ramming, to which the long slivers or the mesh respectively are/is subjected from above for the purpose of compacting them/it, exerts a sudden, abrupt action of a large force, with stored energy being converted within milliseconds, without large kinetic energies having to be evolved.
11. Process according to one of the preceding claims, characterised in that the compressed web is subjected to thickness dressing.
12. Process according to one of the preceding claims, characterised by the use of un-barked raw material of any length.
13. Process according to claim 9, characterised in that when the sticks or slabs are broken up or the mesh is formed, the bark is separated off and removed.
14. Process according to one of the preceding claims, characterised in that the packet strand, which is preferably advanced continuously at constant speed, is supported while being transported through the breaking-up step.
15. Device for producing a coherent web from long slivers which are produced by breaking-up the raw material fed and are then compacted to give a web which is subsequently glued and then pressed together with other webs to give blocks or the like, in particular for carrying out the method according to one of the preceding claims, characterised by the following features:

    a) a conveyor (1) for transporting a continuous packet strand (2) which consists of longitudinally aligned sticks or slabs;

    b) a pressing device (3) arranged above said conveyor (1) extending across the conveyor width, acting vertically downwardly and rolling on the packet strand (2);

    c) a breaking-up device (8) arranged downstream of the conveyor (1) including a plurality of rows of knives (10) aligned transversely to the direction of conveyance (9) and arranged with an offset behind one another and relative to one another, each of said rows of knives (10) being composed of a plurality of splitting knives (11) arranged side by side with a clearance, being guided to be vertically displaceable and being governed by a drive (13) with a short time cycle;

    d) a compacting device (17) provided downstream of the breaking-up device (8), in which the previously split long slivers are compacted to produce a web (18).
16. Device according to claim 15, characterised in that located within the breaking-up device and extending across an increasing conveying width thereof, there are guide elements (22) for deflecting the longitudinally split sticks or slabs, or long slivers respectively, the guide elements (22) being arranged in such a way that guide paths (23) crossing at acute angles are formed for said split sticks or slabs, or long slivers respectively.
17. Device according to claim 15 or 16, characterised in that a metering device for detaching the sticks (7) or slabs from bundles fed is arranged upstream of the packet strand conveyor (1).
18. Device according to claim 15, 16 or 17, characterised by a dressing device associated with the packet strand conveyor (1) to form a packet strand (2) of approximately equal width and height.
19. Device according to one of the claims 15 to 18, characterised in that the pressing device (3) arranged upstream of the breaking-up device (8) has pressing rolls (5) and/or pressing balls which can be actuated by interconnected hydraulic cylinders.
20. Device according to claim 19, characterised in that the pressing rolls (5) include floating mounts.
21. Device according to claim 15 or 16, characterised in that the pressing device (3) arranged upstream of the breaking-up device (8) includes contact pressure blocks (4) with guide strips (6) for improving the parallel guidance of the sticks (7) or slabs.
22. Device according to one of the claims 15 to 21, characterised in that the splitting knives (11) are arranged at least approximately vertically with approximately vertical cutting edges (12) directed against the pocket strand (2).
23. Device according to claim 22, characterised in that the distance (a) between the cutting edges (12) of two splitting knives (11) arranged side by side in one row (10) is smaller than the distance between the rear knife edges.
24. Device according to one of the claims 15 to 23, characterised in that at least the splitting knives (11) of one row (10) are arranged in a common frame (14) which is subject to an oscillating drive (13).
25. Device according to one of the claims 15 to 24, characterised in that the conveyor passing through the breaking-up device (8) comprises driven chains (15) guided through between the splitting knives (11).
26. Device according to one of the claims 15 to 25, characterised in that a plate belt (19) for the web (18) is provided downstream of the breaking-up device (8).
27. Device according to one of the claims 15 to 26, characterised in that arranged in the breaking-up device (8) between the individual rows of knives (10) there are contact pressure devices (16) which firmly compress the packet strand (2) or the mesh being formed from above on the way through the breaking-up device (8).
28. Device according to claim 27, characterised in that the contact pressure devices (16) comprise freely rotating pressure rolls in floating mounts.
29. Device according to one of the claims 15 to 28, characterised in that the splitting knives (11) are arranged with an inclination against the direction of conveyance (9) and thereby form an acute angle with the latter.
30. Device according to one of the claims 15 to 29, characterised in that the compacting device (17) downstream of the breaking-up device (8) is composed of a plurality of power units (17a) which convert the energy stored in them within milliseconds in a rapid time cycle.

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