FI69785B - ANORDINATION FOER BESKICKNING AV FYLLRUMMET I EN HORIZONTAL KOLVSTRAENGPRESS MED EN BLANDNING AV VAEXTPARTIKLAR OCH BINDEMEDEL FOER FRAMSTAELLNING AV IHAOLIGA PROSMAFORMIGA STRAENGPRESSPROFILER - Google Patents

Abstract

1. Device for charging the filling chamber of a horizontal extruder with a mixture of small plant parts and binders in order to produce hollow prismatic extrusion profiles,in which the upwardly open side, facing a charging hopper, of the filling chamber traversed by at least one mandrel can be covered by a reciprocally moving closing slide valve, characterised in that at least one reciprocally driven pair of stop slide valves (16, 17) is arranged so as to laterally enter the filling chamber underneath the mandrel (9).

Description

69785

Apparatus for charging the filling space of a horizontal piston extruder with a mixture of plant particles and a binder to produce hollow rectangular extrusion profiles 5

The invention relates to a device for charging a filling space of a horizontal piston-nozzle blender with a mixture of plant particles and a binder to produce hollow rectangular extrusion profiles, in which device the upwardly closing side of the filling space pierced by at least one mandrel

The piston extruders work in step. The piston protruding into the filling space seals the mixture therein and compresses it through a shaping space into a heated curing channel where the binder binds under the influence of heat during the continuous synchronized movement of the extrudate.

The raising of the filling space of such a piston extruder generally takes place in the form of a free fall from a charging hopper arranged above the filling space and the lower outlet opening of which is limited by a closing slide. In the known device according to DE application publication 28 10 070, there is a passage opening 25 in the closing slide, the cross section of which corresponds approximately to the filling opening of the filling space. When the through hole is aligned with the outlet of the hopper, the filling space can be filled with the mixture. This occurs when the extrusion piston is in the retracted position.

30 In practice, it has now proved expedient to move such a closing slide back and forth at least twice before the extrusion piston performs its compression stroke. It is further known and expedient to select the stroke of the closing slide so large that its passage opening is located in one end position 2 69785 on this side of the filling space and in another end position on that side. Thus, the filling of the filling space takes place during the movement of the closing slide, namely when the passage opening of the closing slide passes the outlet of the loading-5 funnel. As a result of this operation, due to the repeated reciprocating movement of the closing slide, there is a regular distribution of the mixture in the filling space. Extrudates prepared according to this method generally have a more uniform homo-10 genus and density distribution than articles prepared according to previous methods.

Difficulties in charging the filling space occur when the filling space is pierced by a mandrel whose cross section is dominant to form a through cavity in the extrusion profile.

It is known to control an extrusion piston with this spindle. Practice has shown that, contrary to theoretical notions, only circular or oval-shaped spindles have not prevented the production of unusable extrudates. This is because the circular lower edge of the mandrel at least does not prevent the mass filled on both sides of the mandrel from flowing together. As a result, the density below the mandrel is not less than above.

25 If there are certain differences in the charge intensity of the filling space, these are compensated for in the known cross-sectional shapes by an extended stroke of the extrusion piston, as is known from DE-A-29 32 406.

However, the invention seeks to solve a hitherto unresolved problem of producing hollow cross-sectional extruded profiles from a mixture of plant particles and a binder. Such hollow angular cross-sections require a corresponding cross-section of the mandrel in the filling space 35.

3 69785

In the case of horizontal piston extruders, it would then be possible to fill the area of the filling space below the square-shaped mandrel which, due to the free fall of the mixture, which is often not fluid, cannot be sufficiently filled. A vertical cold extruder would not have this problem. Such cold extruders are known per se for the production of press chip sheets, for which purpose, however, it is necessary to combine the vertical action of the extruder with the horizontal forward pushing movement of the bound extrudate. Such an operation would be impossible in the manufacture of hollow square extruded profiles.

It is therefore a particular object of the invention to enable the production of hollow rectangular extrusion profiles in a horizontal cold extruder.

Based on the known device mentioned at the beginning, the essence of the invention is that at least one other pair of reciprocating pushers, reciprocating from the side and inserted into the filling space below the mandrel, is arranged in the device.

This pair of sealing pushers, arranged at a certain point in the filling space, has the task of pushing (sealing) the damming mixture along the side surfaces of the mandrel into the filling space below the mandrel in this way to obtain approximately similar filling densities around the mandrel.

To this end, the invention proposes that the stroke of a single pusher of a pair of 30 compression pushers corresponds at least to the wall thickness of the extrusion profile, in which case the vertical wall thickness of the extrusion profile is intended if such a profile had different wall strengths.

4,69785

A preferred embodiment of the invention is such that each stroke of the extrusion piston always corresponds to at least two strokes of a pair of compression pushers. It is even conceivable that the movement of a pair of compaction pushers is different from the movement of a pair of slides covering the top of the filling space. Namely, when the passage opening of the slide pair is aligned with the outlet opening of the loading hopper, then the pushers of the sealing pusher pair should be in the retracted, i.e. inoperative position position, where they form a part of the wall of the filling space. But when the normal closing slide is located in its end positions and thus the filling space is covered from above, it is recommended to move the closing pushers into the filling space, which can also take place in a rapid, vibrating manner. This results in the mixture introduced into the filling space in connection with the movement of the first pusher preferably being distributed in the area of the filling space below the mandrel and in subsequent movements of the closing slide the regular introduction of the mixture introduced into the filling space from below upwards.

In view of the above, the invention also offers, within a variant of an embodiment, the possibility that, when fitting the partitions of the extrusion profiles or the inwardly projecting strip-like projections, these are oriented horizontally in the piston extruder and have additional blocking work in their plane. In the case of an extrusion profile with a through-partition, this wall 30 can be systematically filled by means of the invention in both a horizontal and a vertical position. But if list-like projections are used, then it is advisable to fit them horizontally in accordance with the latter feature of the invention and to provide corresponding 35 additional pairs of compression pushers in connection with these 5 69785 list-like projections to ensure regular filling of the filling space.

The details of the invention will become apparent from the drawing. There, the invention is shown schematically and as in Example 5.

Figures 1-3 show cross-sections of hollow rectangular extrusion profiles of different shapes, Figure 4 shows a cross-section of the filling space of a horizontal piston extruder 10, and Figure 5 shows a cross-section of the filling space modification of Figure 4.

The extrusion profile 1 according to Figure 1 has a hollow square cross-section, which in this example is square, without limiting the invention thereto. Thus, rectangular, trapezoidal and polygonal cross-sections are also included in the review according to the invention, all of which have in common that they are based on an angular cavity 4, the cross-section of which may or may not be proportional to the overall cross-section. If such an extrusion profile 1 according to Fig. 1 is manufactured in a horizontal piston extruder, then it is difficult to make the bottom wall of the extrusion profile 1 equal to the other walls.

In the exemplary embodiment of Fig. 2, an extrusion profile 2 with a partition wall 6 is shown in cross-section, whereby distinct faceted cavities 4 are formed.

6 69785

Finally, Fig. 3 shows an extrusion profile 3 with inwardly projecting strip-like projections 7, so that an I-shaped triangular cavity 4 is formed.

The representation of the extrusion profiles according to these Figures 1-3 is not exhaustive, but it should nevertheless illustrate that the solutions described below make it possible to produce such and similar profiles with a horizontally located piston extruder 10.

The example of Figure 4 shows the filling space 8 of the horizontal piston extruder in cross section. This filling space 8 is pierced by the mandrel 9, namely in the extrusion direction, so that with such an arrangement 15 an extrusion profile according to FIG. 1 can be produced. The filling space 8 is bounded on the side by side walls 10 connected to the base 11.

Thus, a U-shaped base profile is provided, the upwardly open side of which is delimited by a closing slide 13, which separates the filling space 8 from the loading funnel 12 with a mixture of plant parts and binders. Particles from the plant can consist of wood chips, wood fibers, sawdust, but also agricultural waste products, such as straw and the like. These particles are provided with a suitable binder which has the property of binding under the influence of heat and providing a strong structure of the particles joined together in an extrusion process. If it proves expedient to add other types of particles, the invention also covers this possibility.

The closing slide 13 according to Fig. 4 has a through-opening 14 which corresponds approximately to the outlet-cross section of the charging hopper 12, in which the mixed mass to be pressed is located in the hopper. As soon as the closing slide 35 13 has been set 7 69785 by means of the impact actuator 15 schematically shown so that the passage opening 14 is located at least partially at the outlet of the hopper 12, the mixture can enter the filling space 8 delimited by the side walls 8 and the mandrel 9 under free fall conditions. However, only the substantially vertical areas of the filling space 8 and the point above the mandrel 9 can be filled, in contrast to which the areas below the mandrel 9 remain to some extent unfilled.

According to the invention, folding pushers 16, 17 with their associated impact actuators 18, 19 are provided, which can be moved back and forth in the plane of the area of the filling space below the mandrel 9, as indicated by the arrows. The function of these sealing pushers 16, 17 is to push the mixture in front of them from the sides into the filling space below the mandrel 9, i.e. to fill in there. For this reason, it is advantageous to dimension the stroke of the compression pushers 16, 17 at least as large as the free width of the filling space 8 on the sides of the mandrel 9. To increase this impact 20 to the end position shown by the dotted line in Fig. 4, there is no obstacle if the control of the impact actuators 18, 19 is chosen so that when the crushing pushers 16, 17 hit a considerable resistance, the crushing pushers 25 are not forced to move forward.

It is preferred to use the compression pushers 16, 17 at a higher frequency than the extrusion piston (not shown), the function of which is to seal the mixture in the filling space 8 perpendicular to the plane of the drawing for which the extrusion piston is guided by the mandrel 9.

But it is also expedient to choose the dependence of the movement of the closing pushers 16, 17 with respect to the movement of the closing slide 13. Thus, for example, such a control 35 is provided that as the passage opening 14 passes along the filling space 8, the sealing pushers 16, 17 remain stationary in the initial position 8 69785 shown. But as soon as the closing slider 13 is located in one of the rubber at both of its end positions, the closing slides 16, 17 move back and forth at least once, preferably several times.

Thus, it is provided that the area of the filling space 8 below the mandrel 9 is first filled with the mixture sealed on the sides of the mandrel 9. Once this has been done, the movement of the closing slide 13, 15 can then be continued without the closing pushers 16, 17 no longer moving.

10 Practice has shown that the operation can actually produce the extrusion profiles shown in Figures 1 to 3, as well as these corresponding profiles in horizontal piston extruders, which has hitherto been considered impossible to perform.

The embodiment of Fig. 5 shows the fitting of a filling device for producing the extrusion profiles according to Fig. 2, leaving open whether the extrusion profile to be manufactured has a through-partition wall 6 or strip-like projections 7 according to Figs. 2 and 3. The compression pushers 16, 17 with their actuators 18, 19 are similar to or counter, however, in the horizontal plane of the strip-like projections 7 (cf. Figs. 2 and 3) are provided additional compression pushers 20, 21 with corresponding impact actuators 25 22, 23 for filling the mass on the sides of the spindles 9 into the space between the spindles 9.

It is clear that the order of the movements of the compression pushers 16, 17 on the one hand and 20, 21 on the other hand is adapted to each other. Preference is given, of course, to the naturally occurring crushing pushers 16, 17 and only then to the central crushing pushers 20, 21.

The presentation of the above embodiments may give the impression that the theory according to the invention would be time consuming, since the movements of the sealing pushers 16, 17, 35 20, 21 and the closing slide 13 must take place, 9 69785 before the extrusion piston can perform compaction in the extrusion direction. However, this is a mistake, as practice has shown that an extrusion piston which performs a large compaction distance at a relatively low thrust speed 5 can in principle produce high quality extrusion products.

Claims (4)

69785 10 An apparatus for charging a filling space of a horizontal piston extruder with a mixture of plant particles and a binder 5 for producing hollow rectangular extrusion profiles, in which device at least one one other pair of compaction pushers (16, 17) reciprocating from the side into the filling space below the mandrel (9). Device according to Claim 1, characterized in that the impact of the individual pusher of the pair of compression pushers (16, 17) corresponds at least to the wall thickness of the extrusion profile (1, 2, 3). Device according to Claim 1 or 2, characterized in that each stroke of the extrusion piston 20 always corresponds to at least two strokes of a pair of compression pushers (16, 17). Device according to Claim 1 or one of the following claims, characterized in that, when fitting the partitions (6) of the extrusion profiles (1, 2, 3) or the inwardly projecting strip-like projections (7), these are oriented horizontally in the piston extruder and are arranged in the plane. additional pairs of compaction pushers (16, 17) reciprocatingly.