CN1006535B - Extrusion method and apparatus for plant fragments mixed with binder - Google Patents

Abstract

In order to reduce the specific weight and to increase the flexural strength and the modulus of elasticity of the extruded product (1) during the extrusion of the binder-mixed plant fragments, in particular wood fragments, the invention proposes that, during the introduction of the mixture into the extrusion chamber (10) of a piston extruder, the mixture is influenced at least in that the longer fragments are aligned (6) in an orientation approximately parallel to the extrusion axis (5). The protective layers (2, 3) of the mixture are then pre-compressed and extruded to a small extent, so that the already longitudinally oriented chips are fixed in position and the position does not change during the subsequent extrusion stroke.

Description

The invention relates to a method and a device for pressing plant fragments, especially wood fragments, mixed with a special weather-resistant adhesive in a piston extruder which is connected to heat-hardening channels in which the mixed The material is pre-compressed perpendicular to the extrusion axis before the extrusion stroke.

Such an invention is known from DE-AS 1247002, which aligns each pressurized small fragment in a certain direction during the extrusion process. For this purpose, the mixture is pre-compressed with a large degree of compression in a vertical pressurization line with a vertically acting pressurization piston during the first stage of pressurization. The final extrusion is then carried out during the second stage of pressurization with a horizontally acting extrusion piston. When one understands this specification, it will be seen that although the fragments at the outer extent assume a position approximately parallel to the surface, this is also long known from the molding process of extruded plates. There is still a random arrangement of fragments in the center of the billet, especially when producing thick-walled extrusions. Furthermore, the previously known solutions erroneously assume that the greater compression of the mixture during pre-extrusion increases the flexural strength of the extruded product. During pre-extrusion, the more intense the compression, the poorer the parts which are extruded relative to each other during extrusion are bonded. Therefore, such products are relatively prone to breakage along the joining surfaces of these individual parts, so that no usable flexural strength can be obtained.

Therefore, the basic task of the present invention is to further improve the already known extrusion method as follows: the longitudinal bending strength of the extruded product is greatly increased, but at the same time the individual extruded parts are tightly bonded, so that along these bonding areas There is no longer any danger of cracking. The present invention also specifically seeks to produce very strong high-quality extruded panels with a low specific gravity and an adhesive that is not affected by wind and rain, for applications such as inner walls of buildings, sheds, etc., for which the extruded panels have the required strength .

The solution of the above-mentioned task of the present invention is to be mixed with part longer fragments, when the mixture of for example pin-shaped fragments is fed into the extrusion chamber, the longer fragments are parallel or approximately parallel to the extrusion axis, thereby at least for the longer fragments The orientation works effectively, and the mixture is then pre-compressed at a small compression ratio so that the aligned fragments in the outer layer remain in place during subsequent extrusion strokes.

The invention proceeds from the recognition that in the final extruded extruded product, distinct layers must be extruded, in particular longer fragments must have an orientation essentially parallel to the extrusion direction at least in the outer layer, Strength also does not only depend on fragments being large parallel to a large extrusion surface. When this parallel is longitudinal, the strength will also increase a lot.

However, this orientation cannot be achieved solely by pre-extrusion of the compound, but at least the longer fragments of the compound must be pre-orientated when they are loaded into the extrusion chamber of the extruder. Therefore, the choice of pre-compression compression ratio should ensure that the orientation state of the fragments remains unchanged, and there will be no fundamental changes during the extrusion process. The optimal compression ratio of the pre-compression mixture is about 1:1.5 to 1:2.5 , 1:2 is preferred.

The pre-orientation of the chips takes place during the free fall of the chips into the extrusion chamber during charging. Surprisingly, this can be achieved in a very simple manner by filling the mixture with narrow, longitudinally extending wells in the direction of extrusion, which consist of vertically arranged thin shafts at a distance from each other. The wall web is formed, and the position of the web is fixed.

This orientation principle is already known by DE-OS2926087, wherein naturally be provided with a fibrous web, and this is necessary for the pressure forming of wooden pressboard. In addition, webs of different heights must be comb-staggered and subjected to vibrations.

However, the present invention uses webs of fixed position and same height which are mounted at a greater distance to one side of the extrusion chamber than in the prior art.

Another important idea of the invention is to compress the mixture collected in the extrusion chamber beforehand from both sides. Due to the structure of the webs described above, the pre-compression die must squeeze through the wells between the webs. make. However, the extrusion stroke of the pre-compression die is also limited by the height of the web. Consequently, only a limited compression of the outer layer can result with each pre-compression mold. This limited compression is much smaller than in DE-AS1247002.

However, this creates the prerequisite that precompression is not disadvantageous even if the individual extruded parts are joined to each other extremely firmly.

The method of the present invention can use either a vertically acting piston extruder, a horizontally acting piston extruder, or oblique extrusion. However, since horizontal extrusion is generally adopted, it is only used as a starting point, but not limiting the present invention.

In the dependent claims of the present invention, many solutions are mentioned, and the technical effects of these solutions can be seen from the accompanying drawings and the description of the invention. But unexpectedly, one can change the longitudinal orientation of fragments with appropriate methods. For example, one can have fragments in the outer layer preferentially oriented longitudinally, while in the inner layer more or less tangled. At the same time, longitudinal alignment of the fragments is sought, at least to a considerable extent, throughout the thickness of the extruded product. This is especially important when extruded products should have longitudinal through holes. At this time, it can be surprisingly found that when the method of the present invention is adopted, the wall around the through holes is compressed into a shell shape, and fragments are also found to be longitudinally oriented and arranged between the through holes. Surprisingly, the closer the vias are to the vias, the easier it is to align in the longitudinal direction. However, in order for the extrusion chamber to be fully charged, a minimum distance must be maintained. The optimal distance between vias is equal to or slightly greater than the radius of the vias.

In addition, the present invention proves that the upper pre-compression die is manipulated to move along the web covering the feed opening of the extrusion chamber in order to open the extrusion chamber for the filling process. According to experience, a part of the mixture accumulates on the upper end surface of the web during free fall. Therefore, a scraper moving along the web or perpendicular to the web can be added to scrape off the mixture, thereby facilitating the alignment of the fragments in the desired orientation.

Further details of the invention can be obtained from the dependent claims, the drawings and the description. In the drawings, the invention is described by way of illustration or example. Attached are:

Figure 1: Partial perspective view of a multi-layer extrusion product;

Figure 2: Partial perspective view of the multi-layer extrusion product in Figure 1 when there are straight through holes;

Figure 3: Partial perspective view of the extruded product along the III-III section in Figure 2;

Figure 4: Cross-sectional view of the pressure chamber of a piston extruder (perpendicular to the direction of extrusion);

Fig. 5: Fig. 4 is the cross-sectional view of the pre-compression mold in pressurized state;

Figure 6: Longitudinal section view of the piston extruder;

Figure 7: Partial longitudinal section of the feeding device with a scraper;

Figure 8: Cross-sectional view of an extruded product with through-holes, with dimensions;

Figures 9 and 10: Partial perspective views of squeeze pistons in two embodiments;

FIG. 1 shows a partial perspective view of an extruded product 1 which is very thick, for example up to 8.5 cm, and which is suitable for use as planks, building interior walls, bearing panels and the like. The invention also includes thin-walled extruded articles made as described below.

The product 1 produced along the extrusion axis 5 has a typical layered structure which should be formed during extrusion. The upper protective layer 2 and the lower protective layer 3 should be pre-compressed against the inner layer 4 . This is significant in that at least in the protective layers 2 , 3 , especially those longer fragments have a fragment orientation 6 parallel or approximately parallel to the extrusion axis 5 .

Proceeding from this, a mixture of plant fragments, especially wood fragments, and adhesive should be extruded, and the fragments should be mainly slightly longer fragments. However, it is not considered to use different ingredients to form the 2, 3, 4 layers. The adhesive used should be weather resistant.

Figure 2 shows another extruded product 1 in which through holes 7 are straight and parallel to each other. The layer 8 forming the walls of the through hole is compressed more strongly than the inner layer 4 . If the extruded product 1 is sectioned according to FIG. 3 (plane III-III in FIG. 2 ), a longer fragment and an alignment 6 of the fragments parallel to the extrusion axis 5 is also obtained in this section.

Figures 1 to 3 show the products which can be obtained by the process of the invention described below.

The embodiment shown in Figures 4 to 6 is an extrusion chamber 10 bounded by the die profile 12 of a typical extrusion piston. The extrusion piston 20 further described in FIGS. 9 and 10 has the same The extruded product in 1 has a cross-section of the same shape, especially a rectangular cross-section. The piston is actuated perpendicular to the plane of the drawing in FIG. 4 between the extrusion chamber walls 11 . Joining with the upper and lower sides of the die profile 12, a lot of fixed webs 13 are arranged, and there is a certain interval between the webs, such as 8 millimeters apart, and they are thin-walled and vertically positioned tightly. Since wearing parts are involved, strip steel suitable for saw blades should be used. Between the upper webs 13, the mixture in the feeding device 14 can freely enter; the mixture should enter the extrusion chamber 10 in free fall. In the well 18 between the lower webs 13 stands the toothed splines of the lower pre-compression die 16, which in the embodiment reciprocates in the vertical direction indicated by the arrow 22. The free end faces of these wedge-shaped appendages form the strip-shaped pressing surface 40 . The web 13 engages the play in the fitting gap 17 between the lower pre-molds 16 .

The function of the webs 13 is to align the fragments contained in the mixture in the feeder 14 during free fall, so that an orientation 6 of the fragments substantially parallel to the extrusion axis 5 is obtained as shown in FIGS. 1 and 2 . The fragment orientation 6 is facilitated by the reciprocating movement of the feeder 14 (as shown in Figure 6) and its outlet 15 along the web 13. The lower edge of the feeding device 14 can be mounted near the upper edge of the upper web 13 at a certain distance. In this case, a small portion of the mix can be expected to bridge the upper edge of the web 13 . In order to distribute these accumulations correctly and evenly into the extrusion chamber 10, it is best to install at least one scraper 27 on the vibrating feeding device 14 according to FIG. Finale 5 orientations are arranged.

As soon as the extrusion chamber 10 is filled, the upper pre-compression die 19 enters a position between the upper webs 13 by moving longitudinally parallel to the extrusion axis 5, which is approximately the same as that of the lower pre-compression die shown in FIG. The positions of 16 are consistent. In this position, the mixture is effectively precompressed approximately vertically by means of the precompression dies 16, 19 (using a horizontal piston extruder). The wedge-shaped appendages on the pre-compression dies 16, 19 pass through the well 18 between the webs 13 to their final position (as shown in Figure 5), which is similar to that of the extrusion piston shown in Figure 4. The shape 12 matches. In this way, the pre-compression of the protective layers 2, 3 (see Figures 1 and 2) is achieved to such an extent that the subsequent extrusion strokes can firmly combine the various extrusion parts with each other . For example, precompression in a ratio of 1:2 has proven suitable. As a result of this precompression, the already The longitudinally oriented fragments are fixed in their position and remain in this position during the extrusion stroke.

Figure 6 shows a vertical longitudinal section through the extrusion device. The squeeze piston 20 is driven to reciprocate in the horizontal direction according to the arrow 21 . It is best to use an extrusion technology equivalent to DE-PS 29 32 406, that is, to extrude the pre-compressed mixture at least to a strip of 200 mm or more, preferentially to a strip of 400 to 600 mm, and at least part of it is made of The frictional forces affecting extrusion caused by age-hardening channels are reduced or counteracted during the extrusion process. The movement distance of the extrusion piston 20 is represented by the upper and lower arranged webs 13 . Here, the position of the lower pre-press die 16 is described by its stroke direction 22 . In the direction of the extrusion axis 5, the extrusion chamber 10 is connected with an age-hardening channel 25, which is preferably made according to the technical solutions of DE-PS 25 35 989 and DE-PS 27 14 256. On the upper web 13 there is a feeder 14 which reciprocates in the direction indicated by arrow 26 . This feeding device 14 is contained on the carriage 24 of carrying upper die 19 in the embodiment. The upper die 19 enters the well-shaped structure 18 between the upper webs 13 (see FIG. 4 ) at a certain depth, and when the carriage 24 reciprocates, the upper die 19 also attaches the pressure that will be supplied to the extrusion chamber 10. The mixture is stacked neatly. As long as the extrusion chamber 10 is full of compound, the carriage 24 will enter the position where the upper pre-compression die 19 and the lower pre-compression die 16 overlap. Arranged on the carriage 24 are stroke generators 23 which push the upper pre-press mold 19 in the direction of the arrow 22 into the end position shown in FIG. 5 .

During the extrusion stroke of the extrusion piston 20, the pre-compression dies 16, 19 remain in their position shown in FIG. 5 .

One can obtain different effects with the apparatus shown in Fig. 4 to Fig. 6 . If attention is paid to the generation of a large longitudinal fragment arrangement 6 on the entire cross-section of the extruded product 1 shown in Figures 1 and 2, the feeding device 14 should be continuously reciprocated in the direction shown by the arrow 26 , until the extrusion chamber is full of compound. Conversely, if one takes into account that only the protective layers 2, 3 are provided with this preferred longitudinal orientation 6, and that the compound in the inner layer 4 is somewhat tangled without discernible fragments Orientation, then the reciprocating motion is most suitable only when feeding the well 18 (Fig. 4) between the webs 13, while the extrusion for forming the inner layer 4 The feeding of the press chamber can then take place during a substantially reduced feed movement of the feeding device 14 . In this case, there is substantially no interference with the orientation of the fragments in the falling mix.

In view of the above considerations, a scheme that can achieve similar effects is proposed. For example, the feeding device 14 can be modified so that it covers the entire filling range of the extrusion chamber 10. It is then conceivable to subject the web 13 to vibrations along its longitudinal extension, the vibrations being of small amplitude and high frequency. With this measure, a longitudinal orientation 6 of the fragments parallel to the extrusion axis 5 can also be achieved without the dynamic flow effect of the moving feed device 14 shown in FIG. 6 . Such movement is achieved by combining the front face of the web 13 with means for generating vibrations, such as an electromagnetic vibrator. The same purpose can also be achieved if the web 13 is kept in a constant fixed position, while the feeding device 14 is in a vibrating state along the extrusion axis 5 .

In addition, it must be pointed out that the wedge-shaped attachment on the pre-compression dies 16, 19, despite its gap 17, does not cause a pre-compression of the mixture at all. According to experience, the pre-compression pressure is transmitted along the strip extrusion surface 40 . Only band streaks are produced on the surface of the finished extruded product, but there is no adverse effect on the strength. If you do not want to glue the extruded product1 with colored paper, such as glued veneer panels, you can eliminate this streak by simply sanding the surface a little.

If the extruded product 1 shown in FIG. 2 is to be produced, the distance of the through-holes 7 from each other is important. In known extruded products, the distance between the through holes 7 is at least 1.5 times the radius of the through holes 7 . In contrast, the present invention proposes to reduce this distance. This distance is shown in FIG. 8 to be approximately equal to half the diameter D of the through-hole 7 . The optimum distance may be slightly larger than the suggested size ratios above, but significantly smaller than the known size ratios. Tests have shown that the dimensions shown in FIG. 8, on the one hand, allow an optimum compressive layer 8 (see FIG. 2), which is arched around the individual through-holes 7, to be obtained. On the other hand, when the material is supplied to the extrusion chamber 10, the core web 34 located between the through holes 7 has a considerable part of the fragments 6 arranged parallel to the extrusion axis 5, as shown in FIG. 3 .

However, the closer the through-holes 7 are to each other, the more difficult it is for the fragments to fall into the part of the extrusion chamber below the mandrel forming the through-holes 7 . In order to avoid this defect, the lower pre-compression die 16 can be reciprocated perpendicular to the extrusion axis 5 together with the lower web 13 and the shell that accommodates these components while feeding movement while distributing the mixture accumulated in the lower part of the extrusion chamber through this movement (Figure 4).

Finally, a partial perspective view of the pressing piston 20 is shown in FIGS. 9 and 10 . Known by DE-AS 12 47 002, the end face of extruding piston 20 is that the concave shape retracts and installs. Instead of this mounting method, FIG. 9 illustrates a convex shape formed by a protruding end striation 35 and two intermediate striations 36 which are constantly shifting into each other and slightly set back. However, unlike the known specifications, there is an undulating bend 39 at the edge portion between the joining lines 37, 38, whereby an advantage is obtained that the mutually bonded extruded parts snap together more tightly, while The orientation of the fragments is not substantially affected6.

In the embodiment shown in FIG. 10 , the end surface of the extruding piston 20 has a concave arch structure 41 , and turns into a circular zigzag 42 along the edge of the piston.

In both cases of Figures 9 and 10, the extrusion piston should be cooled to prevent premature sticking of the portion of the compound that is against the extrusion piston.

The end face stripes of the extrusion die can be changed to wedge stripes and screwed on the respective die bodies. In such cases, it proves to be advantageous if a stud screw is used, since its replication on the extruded object promotes a tight bond of the extruded parts which are extruded against each other.

Attached list

1. Extruded products (eg, boards)

2. Upper protective layer

3. Lower protective layer

4. Inner layer

5. Extrusion shaft

6. Fragment Orientation

7. Through hole

8. Compression layer

9. Separation surface

10. Extrusion chamber

11. Squeeze the chamber wall

12. Die shape

13. Web

14. Feeding device

15. Export

16. Lower pre-compression mold

17. Clearance

18. Well structure

19. Upper pre-compression mold

20. Squeeze piston

21. Squeeze the stroke direction of the piston

22. The stroke direction of the pre-compression die

23. Stroke generator

24. Carriage

25. Age Hardening Channel

26. The stroke direction of the feeding device

27. Scraper

28. Web extension

29. Single open room

30. Stroke direction

31. Rotating web

32. Steering shaft

33. Mixture

34. Core web

35. End stripes

36. Middle Stripe

37. Coupling

38. Closing line

39. Wavy bend

40. Ribbon extrusion surface

41. Concave arch structure

42. Jagged stripes

Claims (15)

1, utilize the especially method of wooden flakes of phytoclasts that piston extrusion machine compacting is mixed with weather proof especially adhesive, this extruder is connected with heating age-hardening passage (25), in passage, compound was carried out precommpression perpendicular to extrusion axis (5) before extrusion stroke, it is characterized in that, to be mixed with the longer fragment of part, for example the compound of pin shape fragment is when infeeding extrusion chamber (10), will the parallel or approximate extrusion axis (5) that is parallel to of longer fragment, thereby at least longer fragment aligned the generation useful effect, then compound is carried out precommpression with small reduction ratio, the position of fragment in extrusion stroke subsequently that has aligned in the skin (2,3) remained unchanged.

2, by the described method of claim 1, it is characterized in that compound is with about 1: 1.5 to 1: 2.5 compression ratio, the compression ratio that preferentially adopted 1: 2 carries out precommpression.

3, by the described method of claim 2, it is characterized in that, fragment is aligned by in compound free-falling scope, being parallel to extrusion axis (5) and stretching, erect the thin-wall web plate of installing (13) with spacing distance.

4, by the described method of claim 3, it is characterized in that, the compound that is deposited on the web is scraped in the scope of the well columnar structure between the web.

5, by the method for claim 1, it is characterized in that compound is to infeed extrusion chamber at the feeding device that discharging opening is arranged when extrusion axis moves back and forth.

6,, it is characterized in that the compound in the extrusion chamber carries out precommpression by the well columnar structure between the constant web of fixed-site by the described method of claim 1.

7, by claim 1 or 6 described methods, it is characterized in that, will be through extrude at least rectangular to more than 200 millimeters of precompressed compound, preferential extrusion to 400～600 millimeters rectangular, and have at least frictional force that a part is caused by the age-hardening passage, the influence extruding in the extruding process, to be reduced or to offset.

8, by the described method of claim 1, it is characterized in that, extrusion piston is cooled off.

9, implement the equipment of the described method of claim 1, form by a piston extruder, this extruder is equipped with the extrusion chamber of band heating age-hardening passage and compresses the device of compound in the extrusion chamber perpendicular to extrusion axis in advance, it is characterized in that, the charging side and the offside that are right after extrusion chamber (10) dispose many settings and are parallel to extrusion axis (5), thin-wall web plate spaced a certain distance (13), between these webs, perpendicular to extrusion axis (5), the pre-pressing mold of handling (16,19), be moveable to the corresponding plane of the pressing mold profile (12) of extrusion piston (20) on.

By the described equipment of claim 9, it is characterized in that 10, the pre-pressing mold of each of pectination profile (16,19) has the gap (17) of the held web (13) that is parallel to the extrusion axis stretching, extension at the formed between cog of its banded compressive plane (40).

By claim 9 or 10 described equipment, it is characterized in that 11, configuration moves to the position that covers this charging door along web (13) from the position of an open charging door for the pre-pressing mold (19) of extrusion chamber (10) charging door.

12, by the described equipment of claim 9, it is characterized in that this equipment is furnished with a movable scraping plate (17) that acts on the compound (33) that is deposited on the web (13).

13, by the described equipment of claim 9, this equipment be furnished be parallel to extrusion axis, by extrusion chamber and extrusion piston, in extruded product, form the plug of through hole, it is characterized in that the distance between plug roughly is equivalent to the radius of plug.

14, by the described equipment of claim 9, the end face wedgewise of extrusion piston in this equipment, it is characterized in that, the mid portion of extrusion piston (20) end face is the striped (35,36) of spill or convex, and the edge part of extrusion piston (20) is divided into corrugated or dentation perpendicular to extrusion axis (5).

15, by the described equipment of claim 9, it is characterized in that the pre-pressing mold (16) that web (13) and guider are housed with respect to the charging door place is back and forth handled perpendicular to extrusion axis.

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