LT4826B - Method of extrusion of small plant parts, extruder and filling device for filling and pressing chamber of the extruder - Google Patents

Abstract

The invention relates to the horizontal extrusion of small plant parts in ram extruders, where it aims to make it easier to move the filling material to below the heating pipe (7) which runs through the filling and pressing chamber (5) along the extrusion axis. To this end the invention provides for the lateral walls (8, 9) to be displaced backwards in opposite directions before the start of the extrusion stroke and to be returned to their original position after filling. This makes it possible not only to secure the filling density below the heating pipe (7) but also to achieve a longer expulsion of pressed material for each ram stroke.

Description

BACKGROUND OF THE INVENTION The present invention relates to a method of extruding hollow sections from vegetable, especially wooden, particles by a horizontal piston extruder having a feed shaft lower end entering a filling and compression chamber and closed by a reciprocating sliding shut-off valve having an extruder piston in the compression chamber along at least one heating tube in the direction of extrusion and also in an extruder for implementing this method.

An extruder with the above features is known from DE-A-28 10 070.

The problem with the known extruder of this type is that the filling and compression chamber is unevenly filled with plant particles, which, when the extruder is raised, creates zones of different density in the already manufactured profile. This unevenness is caused by a heating tube arranged so that the plant material fed from the feeding shaft fills a sufficient area under the heating tube.

Thus, it is an object of the present invention to improve the filling of the fill and compression chamber with plant particles, avoiding as much as possible areas of different density in the profile, and generally improving the efficiency of the extruder.

The operation of the extruder according to the present invention differs from that of the analogue in that the filling and compression chamber is extended transversely to the extruder axis by moving the forming walls transversely and simultaneously, and the filling material can flow more easily under the heating pipe.

A suitable embodiment of this method is characterized in that the filling and compression chamber has a molding wall that moves rhythmically and simultaneously from one another across the axis of the extruder, which during the filling material is moved back against the front and back of the shaft wall.

Through the reciprocating reciprocating shut-off valve, the filling material is fed into the chamber which has been emptied by returning it to its original position by the forming wall.

Due to the movement of the back-forming walls to their original position, the filler material is pushed across the extruder axis in the filling and compression chamber, allowing for uniform density underneath the heating tube. This movement of the forming walls furthermore results in the feed rate of the primary extruder lifting line leaving the curing passage much higher than in conventional extruder lifts, resulting in a significant increase in extruder performance.

It is already known from US-A-2 717 420 that both the side forming walls of the extruder filling and compression chamber and its base plate are liftable, thereby compacting the particle mixture during compression. However, this known extruder does not have a heating tube provided in the extrusion and compression chamber in the extrusion direction, which is a drawback, in particular, since the outer surface of the profile is heated and dried but not enough inside. If, however, we were to place such a heating tube in the filling and compression chamber, then the known extruder would not function. This is due to the fact that the base plate of the filling and compression chamber is formed in an elevated manner after the side forming walls have been displaced against one another. Therefore, the heating tube in the filling and compression chamber, pressed against the bottom plate on one side from below, is inevitably displaced from its central position, causing the extruder piston to operate inaccurately and blocking the extruder after a short time.

For this reason, in the present invention, the base plate of the filling and compression chamber is formed rigidly and only the lateral forming walls are synchronously displaced against each other. The side wall forming pressure in the heating tube stabilizes the position of the heating tube.

US-A-2 717 420 does not solve the object of the present invention.

The present invention achieves the following advantages. For example, the displacement of the sliding forming wall is determined to be 30%, at most 50%, of the width of the extruded profile. Correspondingly, the size of the side compression of the mixture fed to the filling and compression chamber is significantly greater than that described in US-A-2 717 420, wherein the lateral displacement of the individual forming wall is only about 1/7 of the profile width. As a result, each section of the extruder of the present invention moves upward in profile lengths and consequently significantly improves the extruder performance.

The displacement of the lateral forming wall is usually caused by hydraulic or pneumatic displacement generators. These according to the invention may be gradual or uniform displacement generators, which is particularly useful for obtaining a pressable mixture of various properties and for changing the performance of the extruder.

The invention proposes to place the bottom edge of a separate forming wall on the most rigid base plate of the filling and compression chamber. The mixture thus fed into the filling and compression chamber is pushed evenly. Similarly, it is suggested that the upper edge of the individual forming wall be attached to the lower surface of the shut-off valve in its closed position.

These measures also require that the shut-off valve must be in the closed position before the lateral displacement of the forming wall begins.

In addition, the invention provides an opportunity to further accelerate or improve the filling and compression chamber filling process.

For this purpose, an occasional mixer is mounted in the lower part of the feed shaft parallel to the extruder axis.

Such a filling device is shown in FIG. 1 of DE-GM 89 06 494.1. The particle mixture is pushed down through a straight feed shaft toward the extruder filling and compression chamber. At the bottom of the feed shaft is a mixer consisting of two blades rotating about a common axis. The purpose of this mixer is to feed the particle mixture into the filling and compression chamber of the extruder faster than would occur if the free mixture had fallen.

Practice has shown that in addition to accelerating the filling process in the filling and compression chamber, pre-compression of the mixture can also be achieved, which increases the extruder performance.

However, if a heating tube is provided in the center of the filling and compression chamber in the extrusion direction, which is particularly necessary when extruding bead bars is desired, a known device is disadvantageous since this heating tube is subjected to transverse deformation of its axis. For this reason, the piston of the extruder that moves the heating tube is subjected to transverse forces during lifting of the extruder because the heating tube and the side walls of the filling and compression chamber are not parallel to each other.

Thus, it has become clear that the known agitator with faster filling and compression chamber filling is not suitable for filling such a filling and compression chamber with a heating tube.

Thus, it is an object of the invention to avoid this disadvantage and to accelerate the filling of the filling and compression chamber containing the heating tube without changing the position of the heating tube.

According to DE-GM 89 06 494.1, the solution to this problem is that the mixer consists of two blades arranged parallel to each other and rotated in opposite directions and eccentrically spaced, while the direction of the filling material in the blades does not coincide with that of the filling material. and a compression chamber in the direction of the passing heating tube.

However, when the two blades are rotating in the same direction about one common axis, each blade must be arranged and rotated separately, the direction of rotation of both blades must be selected so that they move against each other, and the blades must be arranged so that there would be no direct load on the pipe. The main direction of movement of the particles is directed to the space between the heating tube and the side walls of the filling and compression chamber, in which case the lower area of the filling and compression chamber, especially below the heating tube, is more evenly filled with plant particles.

The object of the present invention with counter-rotating blades is successfully used in extruders which do not have displaceable sidewalls in the filling and compression chamber.

It is known from DE-42 14111 A1 that in the feed area of the granulation shaft, two metering rollers are driven parallel to one another to compress the plant material to match the pushing power with the granulation power. However, this does not solve the object of the invention, nor does it render the subject of the invention clearer.

Further embodiments of the invention are set forth in claims 7-14.

For example, point 8 provides that the blade displacement may be chosen such that it extends in opposite positions in its initial position. In this way, an even filling of the filling and compression chamber is achieved. It is further recommended that the feed shaft be hollow cylindrical in the area surrounding the mixer. The agitator then becomes the same as the blade compressor.

The blades can be made of rubber or a solid material such as steel, it is recommended that the blades be spring-loaded.

Sections 12 and 14 provide for mounting the closure housing bracket covering the feed shaft and the filling chamber of the filling and compression chamber to an upper axis of rotation extending parallel to the extruder axis and moving in a rear pendulum motion position with the filling opening or congruently to the feed shaft outlet.

The principle of a rotating feed shaft is known from DE-GM 89 06 494.1. However, the pivot bearing for holding the closure body is separate from the pivot axis of the feed shaft. The present invention combines a mixer according to the invention with a rotatably disposed closure housing for covering the filling opening of a filling and compression chamber, this combination being particularly useful when it is desired to fill the extruder filling and compression chamber with a heating pipe provided therein.

Because the closure body must withstand the lateral pressure of the extruder when in the closed position, it is suggested that the closure body be attached to its bracket so that its height can be adjusted and, thus, the position of the closure body in the closed position accurately adjusted.

These and other features are exemplified schematically in the drawings in which:

Fig. 1 is a cross-sectional view of an extruder filling and compression chamber with a laterally formed forming wall;

Figure 2 is a cross-sectional view of the extruder filling and compression chamber of Figure 1 with the shut-off valve and the forming walls in the closed position;

Figure 3 is a sectional view of a vertical fixed feed shaft for a horizontal extruder filling and compression chamber;

Figure 4 is a sectional view of a vertical rotating feed shaft for a horizontal extruder filling and compression chamber;

Figure 5 is a vertical sectional view of the closed closure body of Figure 4.

Fig. 1 is a cross-sectional view of a filling and compression chamber 5 of an extruder 1 known from DE-A-28 10 070. The pressed particle mixture 3 is in a vertical feed shaft 2, the lower end 4 of which is closed by a shut-off valve 6, which is shown in the open position in Figure 1. This shut-off valve 6 has a passageway 28 having a diameter nearly equal to that of the filling opening 14 of the filling and compression chamber 5. When the closure valve 6 moves back and forth repeatedly as described in DE-A 28 10 070, the distribution of the filler material in the filling and compression chamber 5 is improved.

It is to be understood that binder materials are mixed into the particle mixture 3 and consist of plant particles, particularly wood particles, while the size and nature of the particles as well as their technical properties may vary as desired.

At the center of the filling and compression chamber 5 passes a heating tube 7 which coincides with the axis of the extruder, the function of which is to heat and harden the molded profile from the inside. The extruder piston (not shown in FIG. 1) contacts the heating tube 7. If the profile to be formed is wider than that shown in FIG. 1, it is recommended that several heating tubes 7 be placed side by side and spaced apart to form the extruder piston accordingly.

The filling and compression chamber 5 is bounded on the bottom by a base plate 10 and on both sides by side forming walls 8, 9 which can be slid by horizontal guides 11. The forming walls 8, 9 of Fig. back in the returned, position. Accordingly, the filling opening of the filling and compression chamber 5 is smaller than the space formed between the forming walls 8, 9 in the initial position. In order to fill the space formed by the mixture of particles 3, the closing valve 6 moves repeatedly back and forth.

After completion of the filling process, the filling opening 14 is closed by moving the closing valve 6 from the position shown in Fig. 1 to the position shown in Fig. 2. Thus, the lower plane 17 of the shut-off valve 6 forms a passage to the upper edges 13 of the forming walls 8, 9. The lower edges 12 of the forming walls 8,9 lie on the base plane 16.

The lateral forming walls 8, 9 move from the initial position of Fig. 1 to the position shown in the dashed line, thereby pushing the mixture of particles 3 in the filling and compression chamber towards the heating pipe 7. It is important that the forming walls 8, 9 move simultaneously so as to prevent deformation of the heating tube 7.

The side forming walls 8, 9 have a slant 18 facing each other at their upper and lower edges. These bevels 18 form the bevel surface of the finished profile, which reduces the wear on the edges.

Fig. 1 shows that the displacement of the individual forming wall 8 or 9 corresponds approximately to half the width of the formed profile. This ratio of displacement to width may, of course, be higher or lower. In any case, this ratio is substantially different from that described in US-A-2 717 420, where the displacement of the individual side forming wall corresponds to approximately 1/7 the width of the profile to be formed.

The forming walls 8 or 9 move by means of unobtrusive hydraulically and pneumatically controlled displacement motors, which according to the invention can be adjusted stepwise or otherwise to obtain the appropriate quality of the pressed mixture and / or the required extruder power.

As mentioned above, the effect of the significantly increased displacement of the side forming walls 8, 9 compared to the prior art is that the mixture 3 is compressed not only in the filling and compression chamber 5, but also in the prepared mixture compression profile. Furthermore, the present invention achieves that the heating tube 7 does not move from its initial position during the compression shift.

Fig. 2 shows the closing valve 6 in the closed position after the filling process has been completed and the forming walls 8, 9 are moved along the lower surface 17 of the closing valve to the closed position. The mixture 3 fed to the filling and compression chamber 5 was compressed by 50%.

Another object of the invention is illustrated and described with reference to Figures 3-5.

Figure 3 is a vertical sectional view of the feed shaft 2 through which the plant particles 3 fall down to compress the horizontal extruder in the filling and compression chamber 5. The plant particles can be mixed with binders depending on the properties to be formed in the profile.

At the lower end of the feed shaft 2 is an outlet 14, closed by a shut-off valve 6 which moves transversely and in an open position opposite to the congruent filling opening 14 of the filling and compression chamber 5 is a heating pipe 7 which is inserted into the hollow. the piston rod of the extruder not shown. The axis 7 of the filament tube coincides with the axis of the extruder.

In the lower area of the feed shaft 2 is a mixer 19 which is intended to rapidly and precisely push the plant particles 3 into the filling and compression chamber (5) without changing the position of the heating pipe.

The mixer 19 is composed of two separate and parallel shafts 20, each of which is fitted with a single blade blade.

21. The direction of rotation 22 of the shafts 20 is opposite to one another. In addition, the blades 21 are facing each other in the starting position shown in FIG. In this way, the particles 3 flow in the direction of the arrows 27. This feed direction 27 is deliberately selected so that the particles pass through the heating tube 7 and precisely fill the lower corners of the filling and compression chamber (5).

The agitator 19 shown in Fig. 3 is rotatably mounted in the hollow cylindrical shaft portion 23. The dimensions of the single-blade vanes may be such that they slide along the surface of the inner hollow cylindrical shaft portion 23, although not required. In one embodiment, the blades 21 may be made of flexible rubber, which is useful in the event of particle collision. However, the blade may also be made of a solid material such as steel. It is then recommended to fasten the blades to the shafts 20 elastically or to position the shafts so that they can slide as the particles collide.

Fig. 3 shows a stationary feed shaft 2 with a reciprocating valve 6, while Figs. 4 and 5 show a movably mounted feed shaft 2 with a shutter valve 25 which, together with its holder 26 and the feed shaft 2, can move from an open position. 4, in the closed position shown in FIG. The holder 26 and the feed shaft 2 are rotatably disposed on their axis of rotation 24. The position of pivot 24 is relative. In fact, the feed shaft 2 and the bracket 26 are considerably longer, resulting in a significantly flatter turning path of the closing 25 than shown in Figures 4 and 5.

The similarity of the embodiment of the invention according to Figures 4 and 5 is that filling and closing of the filling and compression chamber (5) can take place even faster, since the agitator 19 is still running during the movement of the feed shaft 2 and the filling and compression chamber 5 areas.

The shut-off valve 25 in the position shown in Fig. 5 must completely close the filling opening 14 of the filling and compression chamber 5 and withstand the pressure exerted on the wall planes during the working displacement.It is recommended to fit the shut-off valve 25 to its bracket 26 so that the height can be adjusted to obtain a proper closing position during installation and can be adjusted when worn. An adjusting device of this construction is shown in the drawing, and adjustment can be made by conventional means.

Claims (14)

DEFINITION OF INVENTION Extrusion of hollow sections from vegetable, in particular wooden, particles (3) by means of a horizontal piston extruder, the bottom end (4) of which feed shaft (2) passes into the filling and compression chamber (5) and is closed by sliding back and forth. a method comprising: pushing an extruder piston in a filling and compression chamber along at least one heating tube provided in the direction of extrusion, characterized in that, prior to raising the extruder, expanding the filling and compression chamber (5) across the extruder axis rhythmically and simultaneously with forming walls (8, 9) movable from one another to facilitate the flow of filler material under the heating pipe (7). An extruder for carrying out the method of claim 1, comprising a feed shaft (2) having a lower end (4) entering the filling and compression chamber (5) and closed by a reciprocating slide having a spout (28). a valve (6), wherein the extruder piston is pushed in the filling and compression chamber (5) along at least one heating tube (7) in the extrusion direction, characterized in that the filling and compression chamber (5) has transverse and simultaneous movement against the extruder axis. forming walls (8, 9), which are extended into position in front of the front and rear wall of the shaft during the filling of the filling material. Extruder according to Claim 2, characterized in that the displacement (15) of the individual forming wall (8, 9) corresponds to 30%, at most 50%, of the width of the extruded profile. Extruder according to Claim 2 or 3, characterized in that the displacement (15) of the individual forming wall (8, 9) is adjustable stepwise or incrementally. Extruder according to Claim 2 or one of the following claims, characterized in that the lower edge (12) of the separate forming wall (8, 9) is arranged on a fixed plate (10) of the filling and compression chamber (5). Extruder according to Claim 2 or one of the following claims, characterized in that the upper edge (13) of the separate forming wall (8, 9) is arranged at the lower surface (17) of the shut-off valve (6) in its closed position. A horizontal extruder filling and compression chamber (5) filling unit comprising a vertical feed shaft (2) for supplying compressible plant particles (3) having a bottom outlet (14) arranged congruently in a shut-off valve (6) and a filling chamber (14) for the compression chamber (5), wherein a mixer (19) rotatably mounted on the lower part of the feed shaft (2) parallel to the axis of the extruder is operable at least occasionally to accelerate the filling process. (21) with shafts (20) rotated in opposite directions and eccentrically disposed relative to one another, while the direction of filling material created by the blades (21) passes through the heating pipe (7) adjacent to the filling and compression chamber (5). 8. Filling device according to claim 7, characterized in that the blades are arranged so that they are facing in opposite positions in the starting position. 9. Filling device according to claim 7 or 8, characterized in that the feed shaft (2, 23) in the area surrounding the mixer (19) has the form of a hollow cylinder. 10. Filling device according to claim 7 or one of the preceding claims, characterized in that the blades (21) are made of rubber. 11. Filling device according to claim 7 or one of the preceding claims, characterized in that the blades (21) are made of a hard metal such as steel and, if necessary, are spring-mounted. 12. Filling device according to Claim 7 or one of the following claims, characterized in that the holder (26) for the feeding shaft (19) and the closure housing (25) covering the filling opening (14) of the filling and compression chamber (5) are pivotally mounted on an upper axis parallel to the axis of rotation of the extruder (24) such that, in the final pendulum movement position, the filling opening (14) is either enclosed in a closure housing (25) or congruent to the outlet (14) of the feed shaft. 13. Filling device according to claim 12, characterized in that the axis of rotation (24) is in the vertical plane of the extruder axis. 14. Filling device according to claim 12 or 13, characterized in that the shut-off valve (25) is attached to its holder (26) so that the height can be adjusted.