HK1200765B - Apparatus for processing plastic material - Google Patents

Description

The invention relates to a device within the meaning of claim 1.

The state of the art has given rise to a number of similar devices of different types, including a receptacle or a cutting compressor for crushing, heating, softening and processing a plastic material to be recycled and a conveyor or extruder connected to it for melting the material so prepared.

For example, EP 123 771 or EP 303 929 describe devices with a reception tank and an extruder attached to it, whereby the plastic material fed to the reception tank is crushed by rotating the crushing and mixing tools and circulated in a drum and heated by the energy supplied at the same time. This results in a mixture with a sufficiently good thermal homogeneity. This mixture is then, after a suitable time, extracted from the reception tank into the screw extruder, and then extruded and plasticized or melted. The screw extruder is placed at about the height of the separation machine. This softening process is actively pushed by the plastic adhesive into the extruder.

It is also generally known to use double-slotted extruders and to attach them to such cutting compressors.

However, many of these long-established designs are not satisfactory in terms of the quality of the plastic material processed at the end of the slug and/or in terms of the slug's throughput.

EP 1 628 812 discloses a device in accordance with the general concept of claim 1.

Depending on the axis of the conveyor and the relative direction of rotation, a distinction can be made between conveyor or conveyor conveyors with parallel and opposite conveyor lines, and conveyor or conveyor or conveyor conveyors with tangent and compact compression.

In the case of opposite snails, the two snails rotate in opposite directions.

The pressure buildup and the drilling are mainly caused by friction of the material rotating with the screw on the upright housing wall in the parallel double-slotted extruder, the drilling is mainly due to a drag flow.

The quality of the pre-treated or softened polymer material entering the conveyor or extruder from the cutting compressor is of essential importance for the final product quality and the situation at the time of insertion and of the conveying or extrusion, if any, is also of importance.

The combinations of cutting compressor and conveyor presented here are therefore of a special nature, since the material entering the conveyor is not directly, untreated and cold-injected, but has already been pre-treated in the cutting compressor, i.e. heated, softened and/or partially crystallized, etc. This is decisive for the entry and quality of the material.

The two systems, the cutting compressor and the conveyor, have an influence on each other and the results of the inlet and further conveying or any compression depend greatly on the pre-treatment and consistency of the material.

The interface between the cutting compressor and the conveyor is therefore an important area, i.e. the area where the homogenised pre-treated material is transferred from the cutting compressor to the conveyor or extruder. On the one hand, this is a purely mechanical problem, since two different devices must be coupled together.

In addition, the exact dosing and feeding of the conveyor is difficult because it is a closed system and there is no direct access to the inlet, but the material is fed from the cutting compressor, so it cannot be directly controlled, for example by a gravimetric dosing device.

It is therefore crucial to carry out this transition both mechanically and with an understanding of the powertrain properties, while at the same time paying attention to the overall process's efficiency, i.e. high throughput and quality.

The distribution mixing effect of such systems is also, according to experience, worse than that of a single-slot and of equal-slip double-slots. However, such systems can build up a corresponding pressure flow to connect the extruder to corresponding tools such as profiles.

In systems where a conveyor or extruder is connected to a cutting compressor, however, the input or feed into the double-slotted conveyor is far from simple to set up and, for example, the dosing cannot be done via a gravimetric doser.

This deliberately chosen arrangement was guided by the desire to stuff or force feed the material into the snail as much as possible. This idea of stuffing the particles in the snail-conveyor into the conveyor or extruder-sniffer was also quite obvious and corresponded to the conventional notions of the specialist, since the part does not precisely change its direction of extrusion and no additional directional or rotational fuel is needed to turn the material. This was done in order to create a more tangible position in the extrusion area, and to increase the radial impact of the material, which can be used to stop the extrusion.

Such devices are generally functional and work satisfactorily, although with recurring problems:

For example, in the case of materials with a low energy content, such as PET fibres or films, or with an early adhesive or softening point, such as polylactic acid (PLA), it has been repeatedly observed that the effect of deliberately plugging the plastic material into the extruder or conveyor inlet under pressure leads to an early melting of the material immediately after or even in the single-sided area of the extruder or conveyor. This reduces the shredding effect of the conveyor and may also lead to a partial return of this melting into the conveyor or conveyor inlet, which results in the melting of the unfused mixture in a more stable manner, as this usually requires the first complete discharge of the melting mixture and the subsequent discharge of the mixture into the melting mixture, and in such cases the melting process can be completed and the final discharge of the mixture can be stopped and the resulting material can be removed and the mixture can be used in the most stable and stable form, and the resulting mixture can be used in the most difficult cases.

In addition, problems arise with polymer materials that have already been heated in the cutting compressor to close to their melting point, where the recess area is overfilled, the material melts and the recess slows.

Problems also arise in the case of materials, which are generally stretched, striped, fibrous, with a certain length extension and low thickness or stiffness, e.g. plastic films cut into strips, primarily because the elongated material is stuck at the outlet end of the screw inlet, with one end of the screw protruding into the receptacle and the other end into the inlet area. Furthermore, since both the mixing tools and the screw run in parallel or exert the same conveying and pressure components on the material, both ends of the screw inlet are subjected to poor pressure and screw inlet in the same direction and the throughput of the screw is no longer resolved. This can lead to further problems in the material's circulation in this area, which can result in a narrowing of the screw inlet and a further increase in the pressure of the screw inlet in this area.

The entrance is therefore also sensitive to opposite double-slug promoters.

The present invention is intended to overcome the aforementioned disadvantages and to improve a device of the type described at the beginning so that even sensitive or striped materials can be easily sucked in by the snails and processed or treated with high material quality and high throughput.

This problem is solved for a device of the type mentioned at the beginning by the characteristics of claim 1.

This first provides that the intended extension of the central longitudinal axis of the conveyor, in particular the extruder, if it has only one conveyor, or the longitudinal axis of the conveyor nearest the inlet, if it has more than one conveyor, passes opposite the conveyor direction on the rotating axis without cutting it, the longitudinal axis of the conveyor, if it has only one conveyor, or the longitudinal axis of the conveyor nearest the inlet, being displaced one radial axis from the conveyor direction to the outer side of the container, downstream of the longitudinal axis parallel to the three-axis, of the axis of the mixing and/or cutting tool in the conveyor direction.

This means that the direction of the conveyor and the direction of the conveyor are no longer identical, as is known from the state of the art, but at least slightly opposite, reducing the stopping effect mentioned at the beginning. By deliberately reversing the direction of rotation of the mixing and crushing tools compared to previously known devices, the pressure on the inlet area decreases and the risk of overflow is reduced.

This prevents the material from melting in the inlet area, thus increasing operational efficiency, extending maintenance intervals and reducing downtime due to any repairs and cleaning measures.

The reduction in the sealing pressure makes the slides, which are known to regulate the filling rate of the slug, much more sensitive and the filling rate of the slug even more precise, making it easier to find the optimum operating point of the system, especially for heavier materials such as high-density polyethylene (HDPE) or PET.

It has also been found to be surprisingly advantageous that materials which have already been softened to close to the melt are better absorbed in the reverse operation according to the invention. In particular, when the material is already in a malleable or softened state, the screw cuts the material from the malleable ring which is adjacent to the wall of the container.

In addition, when working the striated or fibrous materials described above, the deposits or accumulations formed can be more easily dissolved or not formed at all, since on the edge in the direction of rotation of the mixing tools, on the downstream or downstream edge of the opening, the direction vector of the mixing tools and the direction vector of the conveyor show almost opposite or at least slightly opposite directions, so that a longer strip cannot bend and deposit around this edge, but is torn away by the mixing drum in the reception tank.

Overall, the design according to the invention improves the inlet behaviour and significantly increases throughput, making the overall system of cutting compressors and conveyors more stable and efficient.

The opposing double-slotted bolt now benefits particularly from the material from the cutting compressor pre-homogenised by the opposing rotating tools. Furthermore, such a system is particularly suitable for temperature and scare-sensitive materials such as PLA/wood compounds. The cutting compressor plunges the already pre-homogenised, then heated material into the easily filled opposite double-slotted bolt with the lower clogging force due to the direction of rotation and thus ensures that there is no overfill and no premature melting.

The molten material is then usually processed immediately into a profile, especially if it is WPC (Wood Plastic Compound) and in particular PLA/long wood fibre compounds.

The following features describe other advantages of the invention: In particular, it is advantageous to have exactly two conveyors or to have the conveyor trained as an opposite conveyor. This is where the most reliable results can be obtained.According to a preferred further development of the invention, it is envisaged that the conveyors are cylindrically trained and parallel to each other or that the conveyor is trained as a parallel conveyor, in particular as a double conveyor extruder.According to an alternative further development, it is envisaged that the conveyor is conical trained or that the conveyor is conical conveyor or extruder.One conveyor may also be specially designed to take light shock.that one of the slugs is longer than the other.It may also be provided that the slugs are at least in the area of the inlet opening, combed or tangentially trained to meet the requirements of the material to be treated.Another advantageous embodiment, which saves space and effectively inlets, provides that the cross-sections of the slugs are vertically overlapping and the slugs are arranged in the immediate area of the inlet opening, in particular symmetrically to the centre of the inlet opening and at a distance equal to the plane of the inlet opening.Alternatively, it may be provided that the cross-sections of the slug are horizontally overlapping or adjacent and only the slug in the immediate area of the inlet opening is placed at the next corner.

in this context, it is particularly advantageous for the inlet behaviour of the conveyor to turn clockwise from the inlet or tank side, if applicable, towards the beginning of the conveyor towards the end or exit of the conveyor.

This is particularly advantageous for grinding tools, as they are usually very slippery. In known devices with the usual slug rotation, the slug is filled only by the influence of gravity and the tools have only a small influence. This makes it difficult to bring energy into the material, since one often had to specially reduce the external tools in their height or often also omit them. This again affects the melting performance in the slug, because the material in the cutting machine was not sufficiently heated. This is all the more critical for grinders, since grinders are relatively thick compared to sheets and it is all the more important to heat the particles inside.

The rotation of the screw no longer automatically fills the screw and the tools are needed to move the material to the top of the screw, which also provides sufficient energy to facilitate any later melting, which in turn results in increased throughput and better quality, as less cold particles can reduce shearing in the screw, which in turn contributes to improved MFI values.

Preferably both snails have the same diameter.

According to a further development of the invention, the conveyor is arranged on the reception vessel in such a way that the scalar product is oriented from tangential to the plane of the radial outermost point of the mixing and/or crushing tool or to the plastic material passing through the opening and normally to a radial of the reception vessel, in the direction of rotation or movement of the mixing and/or crushing tool (directional vector of rotation) and the directional vector of the reception vessel at each point or in the entire area of the opening or at each point or in the entire area immediately before the opening, radially zero or negative.In particular, the spatial arrangement of the mixing tools and the screw does not depend on the spatial arrangement of the screw, for example the axis of rotation does not have to be oriented normally to the ground surface or to the longitudinal axis of the conveyor or the screw. The directional vector of the direction of rotation and the directional vector of the conveyor are in a normal, preferably horizontal, or in a plane oriented normally to the axis of rotation.

Another advantage is that the directional vector of the direction of rotation of the mixing and/or crushing tool includes an angle greater than or equal to 90° and less than or equal to 180° with the directional vector of the conveyor, measured at the intersection of the two directional vectors at the edge of the opening upstream of the direction of rotation or movement, in particular at the point furthest upstream of this edge or opening. This describes the angle range in which the conveyor must be positively arranged at the receiving end of the conveyor to achieve the desired effects.

A further advantageous design of the invention is that the directional vector of the direction of rotation or motion with the directional vector of the conveyor direction includes an angle between 170° and 180°, measured at the intersection of the two directional vectors in the centre of the opening.

To ensure that no excessive stopping effect occurs, it may be advantageous to provide that the distance or displacement of the longitudinal axis to the radial is greater than or equal to half the inner diameter of the conveyor or check case.

In this respect, it may also be advantageous to measure the distance or displacement of the longitudinal axis to the radials greater than 7%, or even greater than 20%, of the radius of the reception vessel. In the case of conveyors with an extended inlet area or a nut or pocket, it may be advantageous if this distance or displacement is greater than or equal to the radius of the reception vessel.

This is particularly advantageous if the conveyor or the conveyor-beam or the conveyor-beam nearest to the inlet or the inner wall of the housing or the casing of the check is tangential to the inside of the side wall of the container, preferably with the conveyor-beam on its front side connected to a drive and on its opposite front side to an exit opening, in particular an extruder head, located on the front of the housing.

In the case of conveyors which are radially displaced but not tangentially arranged, it is advantageous to provide that the intended extension of the conveyor's longitudinal axis in the direction of conveyance passes through the interior of the reception vessel at least in secant form.

It is advantageous to provide that the opening is connected to the inlet opening directly and directly and without any longer distance or transfer distance, e.g. a conveyor belt, allowing for an efficient and gentle transfer of material.

The reversal of the direction of rotation of the mixing and crushing tools in the container cannot be done by accident or accident, and neither in the case of the apparatus known nor in the case of the apparatus of the invention can the mixing tools be made to rotate in the opposite direction without further delay, especially because the mixing and crushing tools are arranged in a certain way asymmetrically or directionally so that they act only on one side or in one direction. If such an apparatus were deliberately rotated in this direction, neither a good mixing drum would be formed nor the material would be sufficiently crushed or heated. Each has thus fixed its own direction of rotation and cutting of the mixing and crushing machine.

In this context, it is particularly advantageous to provide that the front and front axes of the mixing and/or shredding tools acting on the plastic material in the direction of rotation or movement are differently formed, curved, positioned or arranged compared to the rear and rear axes in the direction of rotation or movement.

A favourable arrangement is to arrange on the mixing and/or shredding tool tools and/or blades which act on the plastic material in a rotational or motion direction to heat, shred and/or cut. The tools and/or blades may be either directly attached to the shaft or preferably mounted on, or formed or shaped into, a rotating tool holder or a supporting disc, especially parallel to the floor surface.

In principle, the effects mentioned are relevant not only for compressing extruders or agglomerators, but also for no-compressing or less compressing conveyor slugs.

Another particularly advantageous design provides that the reception tank is essentially cylindrical with a flat floor surface and a cylindrical sidewall oriented vertically to it. It is also simpler in design when the rotation axis coincides with the central axis of the reception tank. Another advantageous design provides that the rotation axis or the central axis of the reception tank is oriented vertically and/or normally to the floor surface. This particular geometry optimizes the intake behaviour in a structurally stable and easily constructed device.

In this context, it is also advantageous to provide that the mixing and/or crushing tool, or, if several mixing and/or crushing tools are provided in a stack, the lowest, nearest to the ground mixing and/or crushing tool, and the opening are placed at a short distance from the floor, in particular in the lower quarter of the height of the reception tank. The distance is defined and measured from the bottom edge of the opening or intake opening to the bottom of the tank in the periphery of the tank. Since the corner edge is usually rounded, the distance from the edge of the opening of the intended extension to the bottom of the tank is measured at a distance of approximately 400 mm from the intended extension to the outer edge of the tank.

It is also advantageous for machining if the radial outermost edges of the mixing and/or shredding tools reach close to the sidewall.

The container need not necessarily be cylindrical, although this is advantageous for practical and manufacturing reasons. Container shapes which differ from the circular shape, such as conical or cylindrical containers with an elliptical or oval base, must be converted into a cylindrical container of the same volume of barrel, assuming that the height of this fictitious container is equal to its diameter. Heights of containers which are significantly higher than the resulting mixing drum (taking into account the safety distance) are not taken into account, as these containers are therefore not overheated and no longer affect the material used.

The term 'conveyor' here refers to both systems with non-compressing or decompressing conveyor belts, i.e. pure conveyor belts, and systems with compressing belts, i.e. extruder belts with an agglomerating or plasticizing effect.

For the purposes of this Regulation, the term 'extruder' or 'extruder slug' means both extruders or slugs used to fully or partially melt the material and extruders used only to agglomerate the softened material but not to melt it. In the case of aggregate slug, the material is only briefly compressed and sheared, but not plasticized. The aggregate slug therefore produces at its output material which is not fully melted but consists only of particles fused at its surface, which are baked together by sintering. In both cases, however, pressure is applied to the material and the material is compacted.

Further features and advantages of the invention are shown by describing the following non-limiting examples of the subject matter of the invention, which are shown in the drawings in a schematic and non-scale manner: Figure 1 shows a vertical cut by a device of the invention with approximately tangentially connected extruders with overlapping slugs.Figure 2 shows a horizontal cut by an alternative embodiment with approximately tangentially connected extruders with adjacent conical slugs.Figure 3 shows another embodiment with minimal extruder displacement.Figure 4 shows another embodiment with greater extruder displacement.

The design of the containers, the snails and the mixing tools is not in scale, either as such or in relation to each other.

The combinations of cutting compressor and extruder shown in Fig. 1 and Fig. 2 from different positions are very similar in their construction and are therefore described together below.

The advantageous cutting compressor-extruder combinations for processing and recycling plastic material shown in Figures 1 and 2 each have a cylindrical container or cutting compressor or shredder 1 with a flat horizontal floor area 2 and a normally oriented vertical cylindrical sidewall 9.

At a small distance from floor 2, at a maximum height of about 10 to 20 per cent, or less if applicable, of the sidewall 9 - measured from floor 2 to the upper edge of the sidewall 9 - is a flat support disc or tool holder 13 aligned parallel to floor 2 which is arranged around a central pivot axis 10 which is also the central axis of the container 1 into which the direction of rotation 12 marked by an arrow 12 can be attached. The support drive 13 is driven by a 21 motor located below the container 1. On the top of the support disc 13 are the cutters or cutters, which together with the supporting disc 13 and the cutting tool 13 form the 14 small cutters.

As shown in the diagram, the blades 14 on the supporting disc 13 are not symmetrically arranged but are specially trained, positioned or arranged on their front edges 22 pointing in the direction of rotation or movement 12 to have a specific mechanical effect on the plastic material.

The container 1 has a filling opening at the top through which the product to be processed, e.g. portions of plastic foil, is thrown in towards the arrow, e.g. by means of a conveyor. Alternatively, container 1 may be closed and evacuated to at least a technical vacuum, with the material being introduced via a locking system. This product is captured by the circulating mixing and/or shredding tools 3 and rotated upwards in the form of a mixing drum 30, whereby the product is raised along the vertical sides 9 and crushed upwards in the area of the mixing container by gravity and back downwards in the area of the mixing container 12 without any further movement. The height of the mixing device 1 is not to be adjusted in the direction of its movement, and therefore the material can only be rotated upwards in the direction of its movement, either from the top or the bottom, without any special adjustment of the height of the mixing device 12 or 12 and without any further adjustment of the height of the mixing device 12 or 12 and therefore the material can only be rotated in the opposite direction of the mixing device 12 or 12 due to the special adjustment of the mixing device 12 and 12 and 12 respectively.

The plastic material is crushed, mixed and heated and softened by the circulating mixing and shredding tools 3 but not melted by the mechanical friction energy applied; after a certain time in container 1, the homogenised, softened, doughy but not melted material, as discussed in detail below, is released from container 1 through an opening 8 and brought into the intake area of a double-slotted extruder 5 where it is captured by the slugs 6 and subsequently melted.

At the level of the single crushing and mixing tool 3 in the present case, the above-mentioned opening 8 is formed in the sidewall 9 of tank 1 through which the pre-treated plastic material can be extracted from the inside of tank 1. The material is passed to a double-slit extruder 5 located tangentially on tank 1, whereby the housing 16 of the extruder 5 has a casing opening 80 in its casing for the material to be extracted from the slugs 6. Such an embodiment has the advantage that the slugs 6 are driven from the upper slope 7 by a drive only shown in Figure 3 below, so that the drives in the figure 6 above can be extracted from the slope 6 without being driven by the cutting engine. This is not possible in the case of the plastic material 6 or 6 which is not in the shape shown in Figure 6 above.

The intake opening 80 is connected to opening 8 for the conveyance or transfer of materials and is in this case directly, directly and without any longer interval or distance connected to opening 8 and only a very short transfer area is provided.

In case 16, two compressing cylindrical slugs 6 are rotatably stored around their longitudinal axis 15 each. Alternatively, the slugs can also be conical, as shown in Figure 2. The extruder 5 moves the material in the direction of the arrow 17. The extruder 5 is a well-known conventional double-slug extruder, in which the softened plastic material is compressed and thus melted, and the melt is then released on the opposite side at the extruder head.

In the embodiment shown in Figure 1, the two cones 6 are placed vertically on top of each other, and in the embodiment shown in Figure 2, the two cones 6 are placed horizontally next to each other.

Both snails 6 are rotating in opposite directions, so they're opposite.

The mixing and/or shredding tools 3 and/or the blades 14 are at approximately the same height or level as the central longitudinal axis 15 of the lowest snail 6 in Figure 1 or the snail 80 adjacent to the inlet.

In the embodiments shown in Figures 1 and 2, the extruder 5 is connected tangentially to the container 1 as mentioned, or runs tangentially to its cross section. The intended extension of the central longitudinal axis 15 of the lower or of the inlet opening 80 adjacent snails 6 opposite the conveyor direction 17 of the extruder 5 backwards, passes along the axis of rotation 10 in the drawings without cutting them. The longitudinal axis 15 of this snail 6 is parallel to the longitudinal axis 15 at the outlet, from the axis of rotation 10 of the mixing and/or separating tool 3 passes along the conveyor direction of the container 17 through the container 5 to the outer radial axis 11 of the container 1 by 18 knots. In the present case the longitudinal axis 15 of the container 15 runs not parallel to the longitudinal axis 15 but in a straight line.

The distance 18 is slightly larger than the radius of the container 1. This slightly displaces the extruder 5 outwards or the intake area is slightly lower.

Err1:Expecting ',' delimiter: line 1 column 63 (char 62)

In other words, the scalar product is composed of a directional vector 19 of the direction of rotation 12 tangential to the circumference of the outermost point of the mixing and/or crushing tool 3 or tangential to the plastic material passing through the opening 8 and having a direction of rotation 12 of the mixing and/or crushing tool 3 and a directional vector 17 of the extruder's direction of propagation 5 parallel to the central longitudinal axis 15 of the screw 6 in the direction of propagation, zero or negative everywhere but nowhere in each point of the opening 8 or in the radial area immediately in front of the opening 8, respectively.

In the inlet aperture in Figures 1 and 2, the scalar product from the direction vector 19 of the direction of rotation 12 and the direction vector 17 of the direction of conveyance at each point of the aperture 8 is negative.

The angle α between the direction vector 17 of the conveyor and the direction vector 19 of the rotor, measured at the point 20 of aperture 8 and at the edge of aperture 8 which is the furthest upstream of the direction of rotation 12, is approximately 170°.

If you go downwards along the opening 8 in Fig. 2 in the direction of rotation 12, the blunt angle between the two directional vectors will become larger and larger. In the middle of the opening 8 the angle between the directional vectors is about 180° and the scalar product is at its maximum negative, further below it the angle even becomes > 180° and the scalar product decreases slightly again, but always remains negative.

An angle β between the direction vector of the direction of rotation 19 and the direction vector of the direction of conveyance 17 measured at the centre or centre of the opening 8 and not shown in Fig. 2 is approximately 178° to 180°.

The device described in Figure 2 is the first limit or extreme value. Such an arrangement allows a very gentle stopping effect or a particularly advantageous feeding and is particularly advantageous for sensitive materials which are processed near the melting point or for long-range goods.

Figures 3 and 4 are merely illustrative of the connections of the extruder with respect to the direction of rotation of the tools.

An alternative embodiment is shown in Figure 3 where an extruder 5 with two vertically overlapping, opposite cones 6 is not tangential but is connected to container 1 with its front side 7. The cones 6 and the housing 16 of the extruder 5 are aligned to the outline of the inner wall of container 1 in the area of opening 8 and are repositioned at the bottom.

The distance 18 corresponds here to about 5 to 10% of the radius 11 of the container 1 and about half the inner diameter d of the housing 16. This embodiment thus represents the second limit or extreme value with the smallest possible shift or distance 18 in which the direction of rotation or movement 12 of the mixing and/or crushing tools 3 is at least slightly opposite to the conveyor direction 17 of the extruder 5 over the entire area of the opening 8.

The scalar product is exactly zero in the limiting point 20 of Fig. 3 at the furthest upstream point 20 at the furthest upstream edge of aperture 8. The angle α between the direction vector 17 of the conveyor direction and the direction vector 19 of the rotation direction is exactly 90° as measured in Fig. 3. If one goes downwards along aperture 8, i.e. in the direction of rotation 12, the angle between the direction vectors increases and becomes a blunt angle > 90° and the scalar product becomes negative at the same time.

It is also a crucial difference from a purely radial arrangement, since at point 20 or at the edge 20', if the extruder 5 were fully radial, there would be an angle α < 90° and those areas of the opening 8 which are above radials 11 or upstream or downstream in the drawing would have a positive scalar product, so that local molten plastic material could accumulate in these areas.

In Fig. 4 another alternative embodiment is shown, where an extruder 5 with two vertically overlapping, opposite cones 6 is slightly more displaced on the outlet side than in Fig. 3, but not yet tangential as in Fig. 1 and 2. In this case, as in Fig. 3, the rearward extension of the length 15 of cones 6 penetrates the inside of the container 1 secantly. This results in that - measured in the perimeter direction of the container 1 - the opening 8 is wider than in the embodiment of Fig. 3. The distance 18 is also correspondingly larger than in Fig. 3, but slightly smaller than in Fig. 11.

Claims (15)

1. Apparatus for the pretreatment and subsequent conveying, plastification or agglomeration of plastics, in particular of thermoplastics waste for recycling purposes, with a container (1) for the material to be processed, where the arrangement has, in the container (1), at least one mixing and/or comminution implement (3) which rotates around an axis (10) of rotation and which is intended for the mixing, heating and optionally comminution of the plastics material, where an aperture (8) through which the pretreated plastics material can be removed from the interior of the container (1) is formed in a side wall (9) of the container (1) in the region of the level of the, or of the lowest, mixing and/or comminution implement (3) that is closest to the base, where at least one multiscrew conveyor (5) is provided to receive the pretreated material, and has at least two screws (6) which rotate in a housing (16) and which has a conveying, in particular a plastifying or agglomerating, action, where the housing (16) has, located at its end (7) or in its jacket wall, an intake aperture (80) for the material to be received by the screw (6), and there is a connection between the intake aperture (80) and the aperture (8), where the two screws (6) closest to the intake aperture (80) are counter-rotating relative to one another, and the imaginary continuation of the central longitudinal axis (15) of the conveyor (5) or of the screw (6) closest to the intake aperture (80), in a direction opposite to the direction (17) of conveying of the conveyor (5), passes, and does not intersect, the axis (10) of rotation, characterized in that, on the outflow side or in the direction (12) of rotation or of movement of the mixing and/or comminution implement (3), there is an offset distance (18) between the longitudinal axis (15) of the conveyor (5) or of the screw (6) closest to the intake aperture (80), and the radius (11) that is associated with the container (1) and that is parallel to the longitudinal axis (15) and that proceeds outwards from the axis (10) of rotation of the mixing and/or comminution implement (3) in the direction (17) of conveying of the conveyor (5).
2. Apparatus according to Claim 1, characterized in that precisely two screws (6) are provided and the conveyor (5) is designed as a counter-rotating twin-screw conveyor.
3. Apparatus according to any of Claims 1 to 2, characterized in that the screws (6) are cylindrical and are parallel to one another, and in that the conveyor (5) is designed as a parallel twin-screw conveyor or that the screws (6) are conical, and in that the conveyor (5) is designed as a conical twin-screw conveyor.
4. Apparatus according to any of Claims 1 to 3, characterized in that one of the screws (6) is longer than the other(s).
5. Apparatus according to any of Claims 1 to 4, characterized in that the screws (6) are intermeshing or tangential at least in the region of the intake aperture (80).
6. Apparatus according to any of Claims 1 to 5, characterized in that the cross sections of the screws (6) lie vertically one above the other and the screws (6) in the immediate area of the intake aperture (80) are arranged in particular symmetrically with respect to the centre of the intake aperture (80) and are spaced at equal distances away from the plane of the intake aperture (80) or that the cross sections of the screws (6) lie obliquely one above the other or horizontally one next to the other and only the screw (6) closest to the intake aperture (80) is arranged in the immediate area of the intake aperture (80).
7. Apparatus according to any of Claims 1 to 6, characterized in that the screw (6) closest to the intake aperture (80) or the lowermost screw (6), as seen from the start of the screw (6) closest to the intake or container or from the intake aperture (80), towards the end or the discharge aperture of the conveyor (5), rotates in the clockwise direction.
8. Apparatus according to any of Claims 1 to 7, characterized in that, for a conveyor (5) in contact with the container (1), the scalar product of the direction vector that is associated with the direction (19) of rotation and that is tangential to the circle described by the radially outermost point of the mixing and/or comminution implement (3) or that is tangential to the plastics material transported past the aperture (8) and that is normal to a radius (11) of the container (1), and that points in the direction (12) of rotation or of movement of the mixing and/or comminution implement (3) and of the direction vector (17) that is associated with the direction of conveying of the conveyor (5) at each individual point or in the entire region of the aperture (8) or immediately radially in front of the aperture (8) is zero or negative.
9. Apparatus according to any of Claims 1 to 8, characterized in that the angle (α) included between the direction vector that is associated with the direction (19) of rotation of the radially outermost point of the mixing and/or comminution implement (3) and the direction vector (17) that is associated with the direction of conveying of the conveyor (5) is greater than or equal to 90° and smaller than or equal to 180°, measured at the point of intersection of the two direction vectors (17, 19) at the inflow-side edge that is associated with the aperture (8) and that is situated upstream in relation to the direction (12) of rotation or of movement of the mixing and/or comminution implement (3), in particular at the point (20) that is on the said edge or on the aperture (8) and is situated furthest upstream.
10. Apparatus according to any of Claims 1 to 9, characterized in that the angle (β) included between the direction vector (19) that is associated with the direction (12) of rotation or of movement and the direction vector (17) that is associated with the direction of conveying of the conveyor (5) is from 170° to 180°, measured at the point of intersection of the two direction vectors (17, 19) in the middle of the aperture (8).
11. Apparatus according to any of Claims 1 to 10, characterized in that the distance (18) is greater than or equal to half of the internal diameter of the housing (16) of the conveyor (5) or of the screw (6), and/or greater than or equal to 7%, preferably greater than or equal to 20%, of the radius of the container (1), or in that the distance (18) is greater than or equal to the radius of the container (1) or that the imaginary continuation of the longitudinal axis (15) of the conveyor (5) in a direction opposite to the direction of conveying is arranged in the manner of a secant in relation to the cross section of the container (1), and, at least in sections, passes through the space within the container (1) or that the conveyor (5) is attached tangentially to the container (1) or runs tangentially in relation to the cross section of the container (1), or in that the longitudinal axis (15) of the conveyor (5) or of the screw (6) or the longitudinal axis of the screw (6) closest to the intake aperture (80) runs tangentially with respect to the inner side of the side wall (9) of the container (1), or the inner wall of the housing (16) does so, or the envelope of the screw (6) does so, where it is preferable that there is a drive connected to the end (7) of the screw (6), and that the screw provides conveying, at its opposite end, to a discharge aperture which is in particular an extruder head and which is arranged at the end of the housing (16).
12. Apparatus according to any of Claims 1 to 11, characterized in that there is immediate and direct connection between the aperture (8) and the intake aperture (80), without substantial separation, in particular without transfer section or conveying screw.
13. Apparatus according to any of Claims 1 to 12, characterized in that the mixing and/or comminution implement (3) comprises implements and/or blades (14) which perform a comminuting, cutting and heating action on the plastics material in the direction (12) of rotation and movement, where the implements and/or blades (14) are preferably formed or arranged on a rotatable implement carrier (13), in particular a carrier disc (13), which is arranged in particular parallel to the basal surface (2).
14. Apparatus according to any of Claims 1 to 13, characterized in that the manner of formation, set-up, curvature and/or arrangement of the frontal regions or frontal edges (22) of the mixing and/or comminution implements (3) or the blades (14), acting on the plastics material and pointing in the direction (12) of rotation or of movement, differs when comparison is made with the regions that, in the direction (12) of rotation or of movement, are at the rear or behind.
15. Apparatus according to any of Claims 1 to 14, characterized in that the container (1) is in essence cylindrical with circular cross section and with a level basal surface (2) and with, orientated vertically in relation thereto, a side wall (9) which has the shape of the jacket of a cylinder, and/or the axis (10) of rotation of the mixing and/or comminution implements (3) coincides with the central axis of the container (1), and/or the axis (12) of rotation or the central axis are orientated vertically and/or normally in relation to the basal surface (2) and/or that the lowest implement carrier (13) or the lowest of the mixing and/or comminution implements (3) and/or the aperture (8) are arranged close to the base at a small distance from the basal surface (2), in particular in the region of the lowest quarter of the height of the container (1), preferably at a distance of from 10 mm to 400 mm from the basal surface (2).