HK1200761B - 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.

EP 1 233 855 B1 discloses a device in accordance with the general concept of claim 1.

However, most of these long-established designs are not satisfactory in terms of the quality of the plastic material processed and/or the output or throughput of the slug.

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 in which 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 polymer properties, while at the same time paying attention to the overall process's efficiency, i.e. high throughput and quality.

The common feature of the devices mentioned above, which are known from the state of the art, is that the conveyor or rotation direction of the mixing and shredding tools and thus the direction in which the material particles in the receptacle move and the conveyor direction of the extruder are essentially the same or identical. This deliberately chosen arrangement was guided by the desire to push the material into the slug as much as possible or force it to feed. This idea of pushing the particles in the slug direction into the conveyor or extruder neck was also quite close and corresponded to the prevailing notions of the specialist, since this would not allow the part to move in the same direction and would not create an additional direction for the rotating fuel to be turned.

Such devices are generally functional and function satisfactorily, albeit with recurrent problems;

For example, in the case of materials with a low energy content, such as PET fibres or films, or with materials with an early adhesive or softening point, such as polylactic acid (PLA), the effect of deliberately plugging the plastic material into the extruder's inlet area under pressure in a uniform fashion has been repeatedly observed to lead to an early melting of the material immediately after or even in the extruder's inlet area. In addition, the extruder's shrinkage conductivity is reduced, and in some cases the material can partially re-flow into the shrinkage area of the cutting machine or the absorption tank, which results in a further reduction in the stability of the unmelted plastic material, which in turn results in a further reduction in the amount of the melted plastic material, which can be completely removed and the extruder's shrinkage process can be completed and the extruder's shrinkage process can be completed and the extruder's shrinkage process can be completed and the extruder's shrinkage process can be completed in a more stable manner, as a result of which the melted plastic material can be completely removed and the extruder's shrinkage process can be completed and the extruder's shrinkage process can be completed and the extruder can be removed.

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.

Different extruders or conveyors were connected to such uniformly rotating cutting compressors, with generally acceptable and attractive results.

The present invention is intended to overcome the aforementioned disadvantages and to improve a device of the type described at the beginning so that, in addition to the usual materials, also sensitive or striped materials can be easily drawn in from the snail and processed or treated with high material quality, energy saving and with high and constant throughput.

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

The first provision is 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's direction of rotation 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 triangular in the direction of the tool's exit parallel to the longitudinal axis, and radially spaced from the axis of the mixing and/or cutting tool in the direction of the conveyor, towards the direction of the conveyor.

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 material melting in the inlet area, thus increasing operational efficiency, extending maintenance intervals and reducing downtime through any repairs and cleaning measures.

The reduction in the discharge 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 applicant also found that a special design of the mixing and shredding tools allows surprisingly beneficial effects which have a direct impact on the inlet behaviour of the conveyor or extruder.

The invention also provides that the angle γ of the front edge of the radially outermost mixing and/or shredding tool or radially outermost tool and/or cutter nearest the ground satisfies the relation y = k * d + K, wherein d ... the mean diameter of the snail in the area of the inlet opening in mmK ... is a factor or a constant in the range of 15 to 35 k ... a factor in the range of 0.08 to 0.2.

The angle γ is measured at the radial extreme point of the nearest mixing and/or shredding tool or tool and/or knife to the ground, the angle between the extension of the front edge, especially the straight edge, and the radials passing through this extreme point.

The tools circulating in the container have both a stuffing effect on the material and a mixing effect, which drives and mixes the material in the container.

This means that the smaller the angle of attachment to the radials, the smaller the screw. The smaller the angle of attachment, the more the material to be treated is moved in the cutting compressor and the less it is stuffed into the screw. The larger the angle of attachment, the more stuffing the tools or knives do, so the material stays less in the cutting compressor and the particles are cut less often.

The smaller the slurry, the smaller the particles must be, with the already compacted and softened particles behaving fluid-like in the inlet area. This means that the material must be moved more, which causes the material to be more heavily pressurised by the tools or cut by the knives and consequently the particles become smaller. The tools of plants with smaller slurries are therefore more demanding and must be equipped with a correspondingly smaller adjustment angle.

The larger the slug, the more the tool can be plugged or spliced, i.e. the greater the angle of application, because a larger slug can tolerate larger particles or can absorb and process larger particles.

The relationship indicated has led to an optimal cutting and plugging for this particular system.

It has been surprisingly found that, owing to the gentle stopping behaviour due to the opposite direction of rotation of the mixing tools, more aggressive tools can be used in the cutting compressor, which inject more energy into the material. The cutting compressor can therefore be operated at a higher temperature, which in turn results in better homogeneity with reduced residence time. According to the invention, a particularly good and efficient energy supply is achieved by the special adjustment angles of the tools in combination with their reverse direction of rotation of the tools.

In addition, such a combination of a cutting compressor with tools and a rotating direction and an extruder connected to it unexpectedly improves the melting performance of the material in the extruder, since already well-preheated particles enter the shell. This compensates for any inhomogeneities and the material entering the shell from the container and then compressed and melted has a high thermal and mechanical homogeneity. Accordingly, the final performance of the plastic or aggregate at the end of the extruder or aggregator is very high and shells can be used, which - due to the pre-treatment and the introduction of the polymer - cause the material to melt and have a particularly low melting capacity.

In addition, the throughput is more constant over time or the throughput is more uniform and the intake works reliably without problems when filling the snail.

The following features describe other advantages of the invention:

A practical advantage is the angle of 20° to 60°, especially 30° to 50°.

According to a preferred development, it is advantageous if the angle γ also satisfies the ratio γ = k1 * DB + K1, where DB is the diameter of the cylindrical cutting compressor or container in mm or the diameter of a fictitious cylindrical container of the same height converted to the same volume of container,K1 is a factor or constant in the range of 12 to 40. The angle of incidence of the outermost tools depends on the diameter of the cutter. The larger the diameter of the container, the greater the angle of incidence to the radial and the greater the distance of the tool to the wall of the cutter. The tool then acts more as a plugging than a floating one. If the distance to the wall of the container becomes very small, then the particles between the container and the tool will be bent and the disc may block.

In this connection, it has been shown experimentally to be advantageous to have the angle of attachment in the range of 20° to 35° for vessels of less than 750 mm in diameter, 28° to 47° for vessels of 750 mm to 1300 mm in diameter and 35° to 55° for vessels of more than 1300 mm in diameter.

It is particularly advantageous in this context if the radial distance of the tool mb, measured from the radial extreme point of the nearest mixing and/or crushing tool or tools and/or blades provided there, or from the circle defined by this point, to the inner surface of the sidewall of the container, is mb = k3 * D8, where DB ... is the inside diameter of a cylindrical container in mm or the inside diameter in mm of a fictitious cylindrical container of the same height converted to the same volume of container, and k3 ... is a constant in the range of 0,006 to 0,16.

The radial distance of the mb tool is preferably in the range of 15 mm to 120 mm, preferably in the range of 20 mm to 80 mm.

The smaller the angle of application, the closer the tools can get to the wall of the container; the greater the angle of application, the more the cutting of the knives pulls or pulls in, and the further the tools must be from the wall of the container to prevent blocking and braking caused by trapped particles.

The experimental results show that at an angle of 20° to 33° the minimum radial distance of the tool mb is preferably in the range of 15 mm to 20 mm. At an angle of 45° to 60° the minimum radial distance of the tool mb is preferably greater than 35 mm.

Furthermore, the applicant has found that a particular spacing of the mixing and crushing tools allows for favourable effects relative to the conch which have a direct effect on the inlet behaviour of the conveyor or extruder. d ... the mean diameter of the snail in the area of the inlet opening in mmK2 ... is a factor or constant in the range of 20 to 100, in particular 20 to 80,k2 ... a factor in the range of 0,03 to 0,4, in particular 0,04 to 0,25.

The distance ms is measured from the radial extreme of the lowest bottom of the mixing and/or crushing tool, or of the cutting tools and/or cutters provided therein, to a point on the shell of the screw nearest to the opening. The distance ms is along a wheel which starts from the axis of rotation of the container and passes through the opening and the opening to the screw. This is the minimum distance that the cutting edge of the tool can pass if the cutting edge of the tool passes the cutting edge. The operation of the cutting edge of the container is continuous and there is a change in the outermost distance of the cutting edge of the tool.

A further embodiment provides for at least one, preferably several, further tools or blades radially further inwards. The angle of attachment of each tool or blades, measured as the angle γ, at their respective radial extreme points, between the extension of their front edges, especially the straight edges, and the radials passing through that point, is each less than the angle of attachment of the immediately adjacent outermost tool or blades. The further tools or blades are preferably placed further inwards on the same horizontal plane or on the same supporting frame.

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 of the opening. This describes the second angle range in which the conveyor must be positively placed at the intake reservoir 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 at 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 in any way, but only arbitrarily or by accident, and it is not possible - neither in the case of the apparatus known nor in the case of the apparatus of the invention - to make the mixing tools 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 not deliberately turned in the wrong direction, a good mixing drum would not form, the material would not be sufficiently crushed or heated. Each cutter has thus given its fixed direction to the rotating 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.

Tools and/or blades may be either directly attached to the shaft or preferably mounted or formed on or moulded, where appropriate individually, on a rotating tool holder or a supporting disc, in particular 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 receptacle. The distance is defined and measured from the bottom edge of the opening or intake opening to the bottom of the container in the wheel area. Since the corner edge is usually rounded, the distance from the edge of the opening of the intended extension to the bottom of the intended receptacle is measured at a distance of approximately 400 mm from the outer side of the container.

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.

The examples given in the following figures show conveyors with a single conveyor, e.g. single-wave or single-wave extruders, but alternatively conveyors with more than one conveyor, e.g. double- or multi-wave conveyors or extruders, in particular with several identical conveyors having at least the same diameter d, may be provided.

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: Fig. 1 shows a vertical cut by a device according to the invention with an extruder connected approximately tangentially.Fig. 2 shows a horizontal cut by the embodiment of Fig. 1.Fig. 3 shows another embodiment with minimal displacement.Fig. 4 shows another embodiment with greater 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 advantageous cutting compressor-extruder combination for processing or recycling plastic material shown in Figures 1 and 2 has 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 height by gravity and back downwards in the area of the mixing container. The height of the mixing device 12 falls backwards without any special action. The material can be rotated upwards in the direction of its rotation, and therefore can only be moved upwards in the area of the mixing container height by gravity, and then backwards in the area of the mixing container height.

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

At the level of the single crushing and mixing tool 3 in the present case, the 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 single-screw extruder 5 located tangentially on tank 1, the housing 16 of the extruder 5 having a cowl opening 80 in its casing for the material to be extracted from the screw 6. Such an embodiment has the advantage that the screw 6 can be extracted from the bottom screw in Figure 6 by only a widely represented drive, so that the drive in the upper part of the screw is extracted from the top screw without the use of a screw. This is not possible for the screw 6 in the case of the screw 3 or 6 without the use of a screw. This is not possible for the screw 6 in Figure 4 without the use of a screw.

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, a compressing slug 6 is stored rotatively around its longitudinal axis 15. The longitudinal axis 15 of slug 6 and extruder 5 converge. Extruder 5 moves the material in the direction of the arrow 17. Extruder 5 is a well-known conventional extruder in which the softened plastic material is compressed and thereby melted down, and the melt is then released on the opposite side at the extruder head.

The mixing and/or crushing tools 3 and the cutters 14 are at approximately the same height and level as the central longitudinal axis 15 of the extruder 5.

In the embodiments shown in Figures 1 and 2, the extruder 5 is connected tangentially to the container 1 or runs tangentially to its cross section, as mentioned above. The intended extension of the central longitudinal axis 15 of the extruder 5 or the screw 6 in the direction of conveyance 17 of the extruder 5 is carried backwards in the drawing alongside the rotation axis 10 without cutting it. The longitudinal axis 15 of the extruder 5 or the screw 6 is parallel downstream to the longitudinal axis 15 and the rotation axis 10 of the mixing and/or separation tool 3 is passed in the direction of conveyance 17 of the extruder 5 outwards to the radial axis 11 of the container 1 by a distance of 18 knots. In the present case, the extension of the container 15 is not directed to the longitudinal axis 15 but to the inside of the container.

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 delivery 5 parallel to the central longitudinal axis 15 in the direction of delivery at each point of the opening 8 or in the radial area immediately in front of the opening 8, everywhere negative or positive, but nowhere positive.

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.

The angle of adjustment γ is shown in Fig. 2 and is measured at the radial extreme of point 23 of the nearest mixing and/or crushing tool 3 or tool or knife 14 to the ground.

The device described in Fig. 2 has two additional radially inward-pointing blades 14 arranged side by side on the same supporting panel 13 and the angle of attachment of these blades 14 is measured analogously to the angle of attachment γ at their radial extreme points, between the extension of their straight front edges 22 and the radials passing through this point 11.

The L/D ratio, i.e. the ratio of the length L of the slurry 6, measured from the 20' edge downstream of slurry 6 or the 20' point of the inlet 80 at the furthest downstream, to the end of slurry 6 or to the earliest outlet 30 upstream of slurry 6 in housing 16 for the removal of molten metal during storage, distal end 31 of slurry 6, to the nominal diameter d of slurry 6, is given in Figure 2.

The radial distance of the tool mb, measured from the radial extreme point 23 or the outermost point of the blade 14 or the circle defined by it, to the inner surface of the sidewall 9 of the container 1 is shown in Figure 2 as an example, which satisfies the relation mb = k * DB. The tools or blades 14 are above or protruding over the supporting disc 13.

The minimum distance ms between the tool and the screw, measured from the radial extreme point 23 or the outermost point of the blade 14 or the circle defined by it, to the screw 6 envelope, is also illustrated in Figure 2. The distance ms is essentially in the middle of the length of the inlet 80 and on the radial 11 which is oriented at an angle of 90° to the longitudinal axis 15 of the extruder 5. If the tool 3 moves further down or upwards, the distance is again greater. At the edges of the inlet 80 the distance is maximum if the inlet 80 is symmetrical with its length, as in Figure 2.

In Figures 3 and 4, the distances mb, ms and the angle γ have not been shown, but are primarily intended to illustrate the connection possibilities of the extruder.

Figure 3 shows an alternative embodiment in which the extruder 5 is not tangential but is connected to the container 1 by its front side 7. The screw 6 and the housing 16 of the extruder 5 are aligned and repositioned at the bottom to the outline of the inner wall of the container 1 in the area of the opening 8. No part of the extruder 5 protrudes through the opening 8 into the interior of the container 1.

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, in which the extruder 5 is slightly further out than in Fig. 3 but not yet tangential as in Fig. 1 and 2. In this case, as in Fig. 3, the rearward-facing extension of the longitudinal axis 15 of the extruder 5 penetrates the interior of the container 1 in a secant fashion. This results in the opening 8 being wider than in the embodiment of Fig. 3 as measured in the perimeter direction of the container 1. The gap 18 is also correspondingly larger than in Fig. 3, but slightly smaller than the current radius 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 the mixing and/or comminution implement (3) comprises implements and/or blades (14), which with their frontal edges (22), in the direction (12) of rotation or movement, have a mixing, comminuting, cutting and/or heating effect on 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 conveyor (5), in particular one extruder (5), is provided to receive the pretreated material, and has at least one screw (6) which rotates in a housing (16) and which in particular has 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 connection between the intake aperture (80) and the aperture (8), where the setting angle (γ) of the radially outermost mixing and/or comminution implement (3), closest to the base, or of the radially outermost implement and/or blade (14) complies with the following relationship: where d is the diameter of the screw (6) in mm, Kis a factor in the range from 15 to 35, k is a factor in the range from 0.08 to 0.2, where the setting angle (γ) is measured at the radially outermost point (23) of the mixing and/or comminution implement (3), closest to the base, or of the implement and/or blade (14), that is, between the continuation (24) of the, in particular straight, frontal edge (22) and the radius (11) running through the point (23), and in that the ratio of the length (L) of the screw (6), measured from the edge (20') situated downstream in the direction of conveying of the screw (6), or from the point (20) of the intake aperture (80), situated furthest downstream, to the end of the screw (6) or to the first discharge aperture (30) in the housing (16) for the melt situated furthest upstream in relation to the direction of conveying of the screw (6) at the distal end (31) of the screw (6) remote from the container, to the nominal diameter (d) of the screw (6) is ≥7, preferably ≥ 10 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 downstream in the direction (12) of rotation or of movement of the mixing and/or comminution implement (3), 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) of the container (1) 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 the setting angle γ lies in the range from 20º to 60º, in particular 30º to 50º.
3. Apparatus according to any of Claims 1 to 2, characterized in that the setting angle (γ) complies with the following relationship: where

   D_B is the internal diameter in mm of the cylindrical cutter compactor or container (1) with circular cross section or the internal diameter in mm of an imaginary cylindrical container (1) with circular cross section which is of the same height and is calculated to have the same volume capacity,

   K1 is a factor in the range from 12 to 40,

   k1 is a factor in the range from 0.005 to 0.015.
4. Apparatus according to any of Claims 1 to 3, characterized in that the setting angle (γ) for containers (1) with diameters (D) smaller than 750 mm lies in the range from 20º to 35º and/or that the setting angle (γ) for containers (1) with diameters (D_B) of 750 mm to 1300 mm lies in the range from 28º to 47º and/or that the setting angle (γ) for containers (1) with diameters (D_B) greater than 1300 mm lies in the range from 35º to 55º.
5. Apparatus according to any of Claims 1 to 4, characterized in that the radial distance of the implement (mb), measured from the radially outermost point (23) of the mixing and/or comminution implement (3), closest to the base, or implements and/or blades (14) provided there, or from the described circle defined by this point (23), as far as the inner surface of the side wall (9) of the container (1), complies with the following relationship: where

   D_B is the internal diameter in mm of a cylindrical container (1) with circular cross section or the internal diameter in mm of an imaginary cylindrical container with circular cross section which is of the same height and is calculated to have the same volume capacity, and

   k3 is a constant in the range from 0.006 to 0.16,

   where the radial distance of the implement (mb) preferably lies in the range from 15 mm to 120 mm, more particularly in the range from 20 mm to 80 mm.
6. Apparatus according to Claim 5, characterized in that with a setting angle (γ) in the range from 20º to 33º the minimum radial distance of the implement (mb) lies in the range from 15 mm to 20 mm and/or in that with a setting angle (γ) in the range from 45º to 60º the minimum radial distance of the implement (mb) is greater than or equal to 35 mm.
7. Apparatus according to any of Claims 1 to 6, characterized in that the smallest possible distance (ms) between the implement (3) and the screw (6) is described by the following relationship: where

   d is the diameter of the screw (6) in mm,

   K2 is the factor in the range from 20 to 100, more particularly 20 to 80,

   k2 is the factor in the range from 0.03 to 0.4, more particularly 0.04 to 0.25,

   where the distance (ms) is measured between the radially outermost point (23) of the lowermost mixing and/or comminution implement (3), closest to the base, or implements and/or blades (14) provided there, and a point located on the envelope of the screw (6) closest to the intake aperture (80), that is, along a radius (11) that issues from the axis (10) of rotation and passes through the aperture (8) and the intake aperture (80), where the distance (ms) preferably lies in the range from 15 mm to 150 mm.
8. Apparatus according to any of Claims 1 to 7, characterized in that preferably on the same horizontal plane there is provided at least one, preferably a plurality of, further implements or blades (14) situated further inwards radially, where the setting angle of each implement or blade (14), measured at their respective radially outermost points, between the continuation (24) of their, in particular straight, frontal edges (22) and the radius (11) running though this point is in each case smaller than the setting angle of the adjacent implement or blade (14) situated further outwards, where the setting angle of the implement or blade (14) located furthest inside radially preferably lies in the range from 0º to 30º.
9. Apparatus according to any of Claims 1 to 8, 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.
10. Apparatus according to any of Claims 1 to 9, 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 (20') 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.
11. Apparatus according to any of Claims 1 to 10, 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).
12. Apparatus according to any of Claims 1 to 11, 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, in particular an extruder head, arranged at the end of the housing (16).
13. Apparatus according to any of Claims 1 to 12, 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.
14. Apparatus according to any of Claims 1 to 13, characterized in that the mixing and/or comminution implement (3) comprises implements and/or blades (14) which, in the direction (12) of rotation or of movement, have a comminuting, cutting and heating effect on the plastics material, where the implements and/or blades (14) are preferably arranged or formed on or at a rotatable implement carrier (13) which is in particular a carrier disc (13) and which is in particular arranged parallel to the basal surface (2) and/or that the manner of formation, set-up, curvature and/or arrangement of the frontal regions or frontal edges (22) that are associated with the mixing and/or comminution implements (3) or with the blades (14), act on the plastics material and point 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 (10) 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) and/or that the conveyor (5) is a single-screw extruder (6) with a single compression screw (6), or is a twin- or multiscrew extruder, where the diameters d of the individual screws (6) are all identical.