RU2575233C2 - Device for polymer material processing - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: device contains a silo with an installed in it mixing and/or grinding tool with a possibility of rotation around an axis. In a side wall of the silo a hole is made; through it a polymer material is unloaded, and there is a multi-screw conveyor, at least with two screws rotating in the casing. The supposed continuation of the longitudinal axis of the conveyor passes opposite to the direction of transportation past the axis of rotation. The longitudinal axis of the screw nearest to the silo at the output side is displaced by a distance from the parallel longitudinal axis of the radial. The screws are made with the action synchronous to each other.

EFFECT: increased capacity of materials processing.

20 cl, 4 dwg

Description

FIELD OF THE INVENTION

The invention relates to a device for pre-processing and subsequent transportation, plasticization or agglomeration of polymers.

State of the art

The prior art numerous similar devices of various designs are known, including a receiving hopper or a cutting compactor for grinding, heating, softening and processing of recycled polymer material, as well as a conveyor or extruder attached thereto for melting the material processed in this way. In this case, the goal is to obtain the highest quality final product, in most cases in the form of granulate.

Thus, for example, in EP 123771 or EP 303929, devices with a receiving hopper and an extruder connected to it are described, the polymer material supplied to the receiving hopper being crushed by rotation of grinding and mixing tools, subjected to circulation, and simultaneously heated by entering energy. The result is a mixture with a fairly good thermal uniformity. After an appropriate residence time, this mixture is discharged from the hopper into a screw extruder, transported and plasticized or melted. In this case, the screw extruder is approximately at the height of the grinding tools. Thus, the softened polymer particles are actively pressed or stuffed with mixing tools into the extruder.

Also, in principle, the use of twin screw extruders and their attachment to such cutting seals is known.

However, many of these long-known designs do not satisfy with respect to the quality of the processed polymer material obtained at the screw outlet and / or with regard to the screw performance. First of all, when using double screws, special considerations apply, intolerable by the results in the case of individual screws.

Depending on the axial distance between the screw and the direction of its relative rotation, twin-screw conveyors or extruders of synchronized action (unidirectional twist) or counter-action (antidirectional twist) can be distinguished, as well as tangent and tightly engaged.

In the case of synchronous screws, both screws rotate at the same angular speeds in one direction.

Each of these species has special applications and purposes. Transportation and the creation of pressure in a synchronous twin-screw extruder are caused by the friction of the material rotating at the same time with the screw on a fixed body wall, and transportation occurs mainly from the forced flow. In a twin-screw counter-extruder, on the contrary, the principle of forced transportation prevails.

Of great importance for the final quality of the product are, on the one hand, the quality of the pre-processed or softened polymer material coming from the cutting sealant into the conveyor or extruder and the situation during feeding and transportation or possible extrusion. Here, relevant are, inter alia, the length of individual sections or zones of the screw, as well as its parameters, for example, thickness, depth of turns, etc.

The combinations of cutting sealant-conveyor that are available here therefore have special conditions, since the material entering the conveyor is not loaded directly untreated and cold, but has already been pre-processed in the cutting sealant, i.e. heated, softened and / or partially crystallized, etc. It is also crucial for nutrition and material quality.

Both systems i.e. the cutting seal and the conveyor influence each other, and the results of feeding and further transportation or possible compaction strongly depend on the pre-treatment and the consistency of the material.

An important area is therefore the interface between the cutting seal and the conveyor, i.e. the zone in which the homogenized, pre-processed material is transferred from the cutting seal to the conveyor or extruder. On the one hand, this is a purely mechanical problematic place, since here one has to connect two different working devices. Moreover, this interface is also “delicate” for the polymer material, since in most cases it is here near the melting region in a highly softened state, but should not be melted. If the temperature is too low, then productivity and quality fall, and if it is too high and in some places unwanted melting occurs, the power zone becomes clogged.

In addition, the exact dispensing and supply of the conveyor is difficult, since this is a closed system and there is no direct access to the feed zone, and the material is supplied from the cutting seal, i.e. it cannot be acted upon directly, for example through a gravimetric dispenser.

Therefore, it is crucial that this transition is thought out both from a mechanical point of view and with an understanding of the properties of the polymer and at the same time taking into account the profitability of the whole process, i.e. high performance and appropriate quality. Here it is necessary to pay attention to somewhat opposite conditions.

Synchronous multi- or twin-screw conveyors should be operated, as a rule, underloaded. In the underloaded mode, the material feed sets the productivity of the extruder, and high consistency of the material being drawn is required.

It is in systems in which a conveyor or extruder is attached to the cutting seal that loading into a twin-screw conveyor is difficult to configure, and, for example, dosing cannot be carried out by a gravimetric doser. On the contrary, in the cutting seal rotary mixing and grinding tools cause a continuous loading of pre-processed softened particles or a continuous flow of material to the feed opening of the conveyor or extruder.

In addition, the known devices are inherent in that the direction of transportation or rotation of the mixing and grinding tools and, thus, the direction in which particles of material circulate in the hopper, and the direction of transportation of the extruder are basically the same. Such a consciously chosen location was caused by the desire to stuff the screw as much as possible with material or to supply it with force. This idea of stuffing the conveying screw or screw of the extruder with particles in the direction of transportation of the screw was quite obvious and corresponded to the widespread ideas of the specialist, because the particles do not have to reverse the direction of their movement, and thus do not have to apply additional force to reverse the direction. On the basis of further developments proceeding from this, the desire was constantly observed to fill the auger as much as possible and to strengthen this stuffing effect. For example, attempts have also been made to conically expand the feed zone of the extruder or impart a sickle-shaped curvature to grinding tools so that they can fill the screw with a softened material like a spatula. Due to the displacement of the extruder from the inlet side relative to the hopper from the radial position to the tangential effect of the packing, it was further strengthened, and the polymer material was pressed even more strongly into the extruder with a rotating tool.

Such devices, in principle, are capable of functioning and work satisfactorily, albeit with periodic problems.

So, for example, in the case of materials with low energy consumption, such as PET fibers or films, or in the case of materials with a low temperature of stickiness or softening, such as polylactic acid, the effect is constantly observed that intentional packing in one direction under pressure of the zone feeding the extruder or conveyor with polymer material leads to its premature melting directly after the feeding zone or in the feeding zone of the extruder or screw. Due to this, on the one hand, the conveyor action of the screw is reduced, and, in addition, a partial reverse flow of this melt to the area of the cutting seal or the receiving hopper can occur, and this leads to the fact that the not-melted flakes stick to the melt, due to of which it again cools and partially hardens, and, thus, formation or conglomerate in the form of a buildup of partially solidified melt and solid polymer particles occurs. Due to this, the feed zone is clogged, and mixing and grinding tools stick together. As a result, the productivity or output of the conveyor or extruder decreases, since the screw is not full enough. In addition, mixing and grinding tools can get stuck. As a rule, in such cases, the installation must be turned off and completely cleaned.

In addition, problems arise in such polymeric materials, which in the cutting sealant have already been heated almost to the area of their melting. If at the same time the feed zone is full, then the material melts and the power decreases.

Problems also arise in elongated, in most cases, strip-like, fibrous materials of a certain length and small thickness or stiffness, i.e., for example, in polymer films cut into strips. This is primarily due to the fact that the elongated material at the output end of the auger feed hole hangs, with one end of the strip directed to the receiving hopper, and the other to the feeding zone. Since both the mixing tools and the screw rotate in the same direction or exert the same component of the direction of transport and compression on the material, both ends of the strip are loaded in tension and compression in one direction and the strip can no longer separate. In turn, this leads to the accumulation of material in this zone, narrowing the cross section of the feed hole, deteriorating the nature of the load and reducing productivity. In addition, due to the increased loading pressure in this zone, melting can occur, as a result of which the above problems arise.

First of all, for twin-screw conveyors of synchronous action, this stuffing effect is counterproductive, and it is very difficult to avoid overload.

The objective of the invention is to eliminate the aforementioned disadvantages and improve the device of the kind described above so that also susceptible or strip-like materials can be tightened with screws without problems, as well as processed or processed with high productivity with high quality, excluding conveyor overload.

Disclosure of invention

This problem is solved in the device of the type described above by the features of paragraph 1 of the claims.

In this case, first of all, it is provided that the imaginary continuation of the central longitudinal axis of the conveyor, in particular the extruder, if it contains only one screw, or the longitudinal axis of the screw closest to the feed hole, if it contains more than one screw, goes against the conveyor conveyance past the axis rotation, without crossing it, and the longitudinal axis of the conveyor, if it contains only one screw, or the longitudinal axis of the screw closest to the feed hole on the outlet side is shifted by a certain distance Radia tion hopper which is parallel to the longitudinal axis and is directed outwardly from the axis of rotation of the mixing and / or grinding tool in the conveying direction of the conveyor.

Thus, the direction of transportation of the mixing tools and the direction of transportation of the conveyor are not the same as the prior art, but at least slightly opposite, which reduces the aforementioned packing effect. Due to the intentional reversal of the direction of rotation of the mixing and grinding tools in comparison with previously known devices, the load pressure on the feed zone is reduced and the risk of overflow is reduced. Excess material is no longer filled with excessive pressure into the feed zone of the conveyor, but, on the contrary, excess material even moves away from there again, so that, however, there is always enough material in the feed zone, however, it is almost deprived of pressure or loaded with only a little pressure. Thus, the auger can be sufficiently filled and always feed on a sufficient amount of material without its overflow and the occurrence of local pressure peaks at which the material could melt.

Thus, the melting of the material in the feed zone of the extruder is prevented, resulting in increased operating efficiency, extended maintenance intervals and reduced downtime due to possible repair work and cleaning measures.

By reducing the loading pressure, the gates, by means of which it is possible to control the degree of filling of the screw in a known manner, react noticeably more sensitively, and the degree of filling of the screw can be adjusted even more precisely. In particular, in the case of heavy materials, such as high pressure polyethylene or PET, it is easier to find the optimal installation mode.

In addition, it was unexpectedly preferable that materials that have already been softened almost to melt are better loaded in the counter mode. In particular, when the material is already in a pasty or softened state, the screw cuts the material from the pasty ring, which is close to the wall of the hopper. In the case of the direction of rotation in the direction of transportation of the screw of the extruder, this ring would most likely be advanced further, and the screw would not be able to scrape it off, as a result of which the load would decrease. The proposed reversal of the direction of rotation eliminates this drawback.

In addition, when processing the strip-like or fibrous materials described above, the overhangs or clusters formed are easier to separate, or they do not form at all, since the direction vector of the mixing tools and the conveyor direction vector are almost opposite on the outlet edge or in the direction of rotation of the mixing tools or at least slightly oncoming, due to which the elongated strip cannot bend around this edge and get stuck, and is picked up again thrombus in the receiving hopper.

In General, due to the proposed implementation improves the nature of the diet and significantly increases consumption. The whole system of the cutting seal and conveyor becomes due to this more stable and more productive.

In this regard, the applicant experimentally discovered that this very tightening due to changing the direction of rotation of the tools is particularly suitable for synchronous twin-screw conveyors, since the absence of the stuffing effect contributes to underloading and thereby avoids the overload effect. The tightening takes place in a more controlled manner under less pressure, and the performance is higher, or the work is more reliable.

Thanks to this system, it was possible to operate the double auger of synchronous action in the underload mode. Different operating points can be set for different densities. Due to this, in the case of heavy bulk materials, the degree of compaction in the cutting sealant can be kept lower and both underloading and sufficient filling can be ensured. In the case of light input materials, the operating point is selected with a higher sealing power in the cutting seal, and the same effect can be achieved.

Other preferred embodiments of the invention are described by the following features.

In particular, it is preferable if exactly two screws are provided or the conveyor is made in the form of a twin-screw conveyor of synchronous action. In this case, the most reliable results are achieved.

According to one preferred embodiment, it is provided that the screws are cylindrical and parallel to each other or that the conveyor is made in the form of a parallel twin-screw conveyor, in particular a twin-screw extruder.

According to one alternative embodiment, it is provided that the screws are conical or that the conveyor is in the form of a conical twin-screw conveyor or extruder. Such a conveyor is particularly suitable for the reception of light bulk materials.

If it is provided that one of the screws is longer than the other (others), preferably by a length of ≥3 times the diameter of the screw, then there is a preferred possibility of creating melt pressure.

Further, it can be provided that the screws, at least in the area of the feed opening, are made tightly engaged or tangent in order to satisfy the requirements of the material being processed.

According to another compact and effectively addictive preferred embodiment, it is provided that the sections of the screws lie vertically one above the other, and the screws are located in the immediate area of the supply opening, in particular symmetrically with respect to its center, and are equally far removed from the plane of the supply opening.

Alternatively, it can be provided that the cross sections of the screws lie obliquely one above the other or horizontally next to each other and only the screw closest to the feed hole is located in the immediate area of the feed hole.

In this regard, for the nature of the feed, it is particularly preferable if the augers or the screw closest to the feed hole, when viewed from the engine start of the screws close to the feed hole or to the hopper from the engine side, or from the feed hole in the direction of the conveyor end or outlet, rotates or rotates clockwise arrow.

Especially preferred execution turned out to be crushed materials, since they are usually very loose. In known devices with the usual direction of rotation of the screw, it is filled only due to the action of gravity, and the tools have only a slight effect. Due to this, it is difficult to introduce energy into the material, since it was necessary to greatly reduce the height of especially external tools or often even abandon them. Because of this, the melting power in the screw is reduced, since the material in the cutting seal is not sufficiently heated. This is all the more critical in the case of crushed materials, since they are relatively thick compared to films and the more difficult it is to heat particles also inside.

If, according to the invention, the direction of rotation of the screw is reversed, then it will no longer automatically fill up, and tools are needed to transport the material to the top of the screw. Thanks to this, it is also possible to introduce enough energy into the material to achieve subsequent melting. This causes an increase in consumption and quality, since due to less cold particles it is possible to reduce shear in the screw, which, in turn, contributes to an increase in MFI (melt flow index).

Advantageously, the screws have the same diameter.

According to one preferred embodiment, it is provided that the conveyor is located on the receiving hopper so that the scalar product of the direction vector (direction vector of rotation), which is oriented tangentially to the circle described by the radially extreme point of the mixing and / or grinding tool, or to the polymer passing through the hole material, and perpendicular to the radial of the receiving hopper and indicates in the direction of rotation and / or movement of the mixing and / or grinding tool, and the direction vector The conveyance of the conveyor at each individual point or in the entire area of the hole or in each individual point or in the entire area immediately radially in front of the hole is zero or negative. The zone immediately radially in front of the hole is defined as that zone in front of the hole in which the material is right before it passes through the hole, but has not yet passed through it. Thus, the above advantages are achieved and any agglomerate formation caused by the effects of the packing is effectively prevented in the area of the feed opening. In particular, we are not talking about the spatial arrangement of the mixing tools and the screw with respect to each other, but, for example, the axis of rotation should not be oriented perpendicular to the bottom or the longitudinal axis of the conveyor or screw. The reversal of the direction of rotation and the vector of the direction of transportation lie in one, mainly horizontal, plane or in a plane oriented perpendicular to the axis of rotation.

Another preferred option arises due to the fact that the vector of the direction of rotation of the mixing and / or grinding tool encloses an angle of ≥90 ° ≤180 ° with the conveyor vector of the conveyor, and the angle at the intersection of both direction vectors is measured on the upstream relative to the direction of rotation or movement of the edge of the hole, in particular at the point farthest upstream on that edge or hole. Due to this, the angular range in which the conveyor should be located on the receiving hopper to achieve the preferred effects is described. At the same time, at least a slight counter orientation of the forces acting on the material or, in extreme cases, a pressure-neutral transverse orientation occurs in the entire zone of the hole or at each of its points. At no point in the hole is the scalar product of the direction vectors of the mixing tools and the screw is positive, even in the area of the hole does not occur, thereby, too much packing action.

In another preferred embodiment, it is provided that the rotation or movement direction vector encloses an angle of 170-180 ° measured at the intersection point of both direction vectors in the middle of the hole with the transport direction vector. This arrangement is justified when the conveyor is located tangentially on the cutting seal.

To prevent the occurrence of too much action of the packing, it can preferably be provided that the distance or offset of the longitudinal axis from the radial is greater than or equal to half the inner diameter of the conveyor housing or screw.

Further in this sense, it may be preferable to calculate the distance or offset of the longitudinal axis from the radial of ≥7%, even more preferably ≥20% of the radius of the receiving hopper. For conveyors with an extended feed zone, or a spline sleeve, or an extended pocket, it may be preferable if this distance or offset is greater than or equal to the radius of the receiving hopper. In particular, this applies to cases when the conveyor is connected tangentially to the receiving hopper or passes tangentially to its cross section.

In this case, in particular, it is preferable if the longitudinal axis of the conveyor or screw or the longitudinal axis of the screw closest to the feed zone or the inner wall of the housing or the envelope of the screw passes tangentially to the inner side of the hopper side wall, the screw being advantageously connected on its end face to the drive, and at its opposite end end it conveys the material to an outlet located at the end end of the housing, in particular the extruder head.

In the case of conveyors radially displaced, but located not tangentially, it is preferably provided that an imaginary extension of the conveyor longitudinal axis against the direction of conveyance passes through the interior of the receiving hopper, at least in separate sections as a secant.

Preferably, it is provided that the hole is directly and directly and without a large gap or transmitting portion, such as a conveying screw, connected to the feed hole. Thus, an efficient and gentle material transfer is possible.

The reversal of the direction of rotation of the mixing and grinding tools in the hopper can never happen arbitrarily or by mistake, and neither in the known devices, nor in the proposed device can you just make the mixing tools rotate in the opposite direction and, in particular, also because mixing and grinding tools are positioned in a certain way asymmetrically or oriented in a direction so that they act only on one side or in one direction. If such an assembly were made to rotate in the wrong direction, neither a good blood clot would form, nor the material would sufficiently crush or heat up. Any cutting seal has, therefore, a rigidly specified direction of rotation of the mixing and grinding tools.

In this regard, it is particularly preferable if the front sections or leading edges of the mixing and / or grinding tools acting on the polymeric material, indicating in the direction of rotation or movement, are differently formed, curved, installed or arranged in comparison with the rear or catching in the direction of rotation or movement plots.

Moreover, one preferred arrangement provides that on the mixing and / or grinding tool there are tools and / or knives that in the direction of rotation or movement have a heating, grinding and / or cutting effect on the polymer material. Tools and / or knives can be mounted directly on the shaft or located mainly on the rotary tool holder located on, in particular parallel to the bottom, or on the carrier disk, or made in it or molded on it, if necessary, in one piece.

In principle, the mentioned effects are significant not only for compression extruders or agglomerators, but also for non-compression or low compression conveying screws. Also in this case, local overflows are prevented.

In another particularly preferred embodiment, it is provided that the receiving hopper is made essentially cylindrical with a flat bottom and a side wall oriented vertically to it in the form of a side surface of the cylinder. Structurally, simply further, if the axis of rotation coincides with the central middle axis of the receiving hopper. In another preferred embodiment, it is provided that the axis of rotation or the central middle axis of the hopper is oriented vertically and / or perpendicular to the bottom. Due to this special geometry, the nature of the power supply is optimized in a device with a stable and structurally simple design.

In this regard, it is also preferable to provide that the mixing and / or grinding tool, or in the case of several mixing and / or grinding tools located one above the other, the lowest, mixing and / or grinding tool closest to the bottom and the opening, are located at a small distance from the bottom, in particular in the region of the lowest quarter of the height of the receiving hopper. In this case, the distance is determined and measured from the lowest edge of the hole or feed hole to the bottom of the hopper in the region of the edge of the latter. Since the corner edge is rounded in most cases, the distance is measured from the lowest edge of the hole along the imaginary extensions of the side wall down to the imaginary extension of the bottom of the hopper out. Suitable distances are 10-400 mm.

Further, for processing, it is preferable if the radially extreme edges of the mixing and / or grinding tools reach close to the side wall.

The hopper does not have to be in the form of a circular cylinder, although it is preferred for practical and technological reasons. The capacity of silos that are different from the shape of a circular cylinder, for example truncated cone-shaped silos or elliptical or oval cylindrical silos in terms of shape, should be recalculated to be equal to the capacity of circular-shaped silos, assuming that the height of this conditional silo is equal to its diameter. The height of the bunkers, significantly exceeding the thrombus formed (taking into account the safe distance), remains unaccounted for, since such an excessive height is not used and therefore no longer has any effect on the processing of the material.

The term "conveyor" should be understood in this case as installations with non-compression or decompression augers, i.e. purely conveying augers, and installations with compression augers, i.e. extruder screws of agglomerating or plasticizing action.

The terms "extruder" and "extruder screw" in this case should be understood as extruders and screws, with which the material is completely or partially melted, and extruders, with which the softened material only agglomerates, but does not melt. In the case of agglomerating augers, the material is only very briefly compacted and cut, but not plasticized. Therefore, the agglomerating screw gives at its outlet a material that is not completely molten, but consists of particles melted only on its surface, which are as if sintered. However, in both cases, the auger exerts pressure on the material and compacts it.

Brief Description of the Drawings

Other features and advantages of the invention are given in the description of the following examples of implementation of its object, which should not be construed as limiting it and which are schematically and not to scale shown in the drawings, which represent:

FIG. 1 is a sectional view of a device with an extruder connected approximately tangentially with screws lying one above the other;

FIG. 2 is a sectional view of an alternative embodiment of a device with an extruder connected approximately tangentially with cylindrical screws lying parallel to each other;

FIG. 3 - another option with minimal displacement of the extruder;

FIG. 4 is another embodiment with a large displacement of the extruder.

The implementation of the invention

Neither the bins nor the augers or mixing tools are shown on a scale either as such or in relation to each other. So, for example, in reality, the bins in most cases are larger or the screws are longer than shown.

Depicted in FIG. 1 and 2 from different positions of the combination of the cutting seal and the extruder are very similar in design and are therefore described below together. They differ, first of all, by the location of the screws 6 in relation to each other, which is described below in more detail.

Depicted in FIG. 1 and 2, preferred combinations of a cutting sealant and an extruder for preparing or recycling polymeric material comprise a hopper 1 in the form of a circular cylinder with a flat horizontal bottom 2 and vertical side wall 9 oriented perpendicular to it in the form of a cylinder side surface.

At a small distance from the bottom 2, a maximum of 10-20%, if necessary, less than the height of the side wall 9, measured from the bottom 2 to its uppermost edge, there is a flat carrier disk or tool holder 13 oriented parallel to the bottom, which rotates around a central axis rotation 10, which is simultaneously the central middle axis of the hopper 1, in the direction of rotation or movement 12 indicated by the arrow. The carrier disk 13 is driven by a motor 21 located under the hopper 1. On the upper side of the carrier disk 13 are knives or tools, such as cutting knives 14, which together with it form a mixing and / or grinding tool 3.

As shown schematically, the knives 14 are located on the carrier disk 13 not symmetrically, and on their front edges 22 pointing in the direction of rotation or movement 12 are made, installed or arranged in a special way, mechanically acting on the polymer material in a specific way. The radially extreme edges of the mixing and / or grinding tools 3 fit relatively close, by about 5%, of the radius 11 of the hopper 1, to the inner surface of the side wall 9.

The hopper 1 has a loading hole at the top through which, in the hopper 1, for example, by means of a conveying device, the processed material, for example, portions of polymer films, is loaded in the direction of the arrow. Alternatively, it can be provided that the hopper 1 is closed and air is pumped out of it, at least to a technical vacuum, and the material is loaded through a lock system. This material is captured by rotating mixing and / or grinding tools 3 and swirls in the form of a thrombus 30, and the material rises up along the vertical side wall 9, and then approximately in the active height zone H of the hopper 1 again falls inward and downward into the zone of it by gravity the middle. The active height H of the hopper 1 is approximately equal to its inner diameter D.

Therefore, a thrombus is formed in the hopper 1, the material of which is swirling from top to bottom, and in the direction of rotation 12. Thus, due to the special arrangement of mixing and grinding tools 3 or knives 14, such a device can only be operated with a given direction of rotation or movement 12, and the direction of rotation 12 cannot be reversed simply or without additional changes.

The loaded polymer material is crushed by mixing and grinding tools 3, mixed, and at the same time, it is heated and softened due to the introduced mechanical friction energy, but it does not melt. After a certain residence time in the hopper 1, the homogenized, softened, pasty, but not molten material is discharged from the hopper 1 through the hole 8, fed into the feed zone of the twin-screw extruder 5, captured there by the screws 6 and melted, which is explained in detail below.

At the height of the only grinding and mixing tool 3 in this case, the aforementioned hole 8 is made in the side wall 9 of the hopper 1, through which pre-processed polymer material is unloaded from the hopper 1. It is transferred to a twin-screw extruder 5 located tangentially on the hopper 1, and its housing 16 has a feed hole 80 in its side wall for the material captured by the screws 6. Such an option has the advantage that the screws 6 can be driven from the lower end ends of the drawing 7 by a schematically shown drive, so that the upper end ends of the screws 6 in the drawing can be free from the drive. This makes it possible to arrange at these upper end ends an outlet for the plasticized or agglomerated polymer material supplied by the screws 6, for example in the form of an extruder head (not shown). Therefore, the polymer material, without deviating by the screws 6, can be fed through the outlet, which is not possible in the variants of FIG. 3 and 4.

The feed hole 80 is in the feed or transfer material communication with the hole 8 and is connected with it in this case directly, directly and without a long intermediate part. Only a very short transmission area is provided.

Two compression cylindrical screws 6 are installed in the housing 16 with the possibility of rotation around their longitudinal axes 15. Alternatively, the screws can also be made conical. The extruder 5 conveys the material in the direction of the arrow 17. The extruder 5 is a conventional twin-screw extruder known per se in which the softened polymer material is compacted and thereby melts, and the melt then exits from the opposite side on the extruder head.

In the embodiment of FIG. 1, both screws 6 are arranged vertically one above the other, and in the embodiment of FIG. 2 - horizontally next to each other.

Both screws 6 rotate in the same direction, i.e. performed synchronized action.

Mixing and / or grinding tools 3 or knives 14 lie almost at the same height or in the same plane as the central longitudinal axis 15 of the lowest screw 6. The extreme ends of the knives 14 are sufficiently far from the ridges of the screws 6.

As already mentioned, in the embodiment of FIG. 1 and 2, the extruder 5 is connected tangentially to the hopper 1 or passes tangentially to its section. An imaginary continuation of the central longitudinal axis 15 of the screw 6, lower or adjacent to the feed hole 80, against the conveying direction 17 of the extruder 5 backwards leads in the drawing past the axis of rotation 10 without crossing it. The longitudinal axis 15 of this screw 6 is offset from the exit side by a distance of 18 relative to the radial 11 of the hopper 1, which is parallel to the longitudinal axis 15 and directed outward from the rotation axis 10 of the mixing and / or grinding tool 3 in the transport direction 17 of the extruder 5. In this case, an imaginary continuation back of the longitudinal axis 15 does not pass through the inner space of the hopper 1, but passes right past it.

The distance 18 is slightly larger than the radius of the hopper 1. The extruder 5 is offset, thereby slightly outward, or the feed zone is a little deeper.

The term “counter directional”, “counter” or “opposite” should be understood here to mean any orientation of the vectors relative to each other not at an acute angle, as is explained in detail below.

In other words, the scalar product of the vector 19 of the direction of rotation 12, which is oriented tangentially to the circle described by the extreme point of the mixing and / or grinding tool 3, or tangent to the material passing through the hole 8, and indicates in the direction 12 of the rotation or movement of the mixing and / or grinding tools 3, and the vector 17 of the transport direction of the extruder 5, passing in the transport direction parallel to the Central longitudinal axis 15 of the screw 6, at each individual point of the hole 8 or in the zone radially directly in front of the hole 8 everywhere it is equal to zero or negative, but nowhere positive.

At the supply opening in FIG. 1 and 2, the scalar product of the vector 19 of the direction of rotation 12 and the vector of the direction of transportation 17 at each point of the hole 8 is negative.

The angle α between vectors 17 and 19, measured at the point 20 of the hole 8 farthest upstream from the direction of rotation 12 or at the edge of the hole 8 farthest upstream, is almost a maximum of about 170 °.

If you move along the hole 8 further down, i.e. in the direction of rotation 12, the obtuse angle α will increase. In the middle of hole 8, the angle between the direction vectors is about 180 °, and the scalar product is as negative as possible, further to the left the angle becomes even more than 180 °, and the scalar product again decreases slightly, but remains always negative. However, these angles are no longer called angles α, since they are not measured at point 20.

Not shown in FIG. 2, the angle β measured in the middle or in the center of the hole 8 between the vector 19 of the rotation direction 12 and the transport direction vector 17 is 178-180 °.

The device of FIG. 2 represents the first extreme case or extreme value. With this arrangement, a very gentle action of the packing is possible, or a very preferable loading is possible, and such a device is preferable, in particular, for susceptible materials being processed close to the melting region, or for long-strip material.

FIG. 3 and 4 serve only to illustrate the possibilities of connecting the extruder with respect to the direction of rotation of the tools. Values L, B, A are not shown.

In FIG. 3 shows an alternative embodiment, in which the extruder 5 with two synchronous screws 6 lying vertically one above the other is connected to the hopper 1 not tangentially, but with its end side 7. The screws 6 and the extruder body 16 in the area of hole 8 are aligned the inner wall of the hopper 1 and flush shifted back. No part of the extruder 5 or screws 6 passes through the hole 8 into the interior of the hopper 1.

The distance 18 here corresponds to 5-10% of the radius 11 of the hopper 1 and about half the inner diameter d of the housing 16. Thus, this option is the second extreme case or extreme value with the smallest possible offset or distance 18, when the direction of rotation 12 or movement of the mixing and / or grinding tools 3, at least slightly counter-directed to the direction of transportation 17 of the extruder 5, namely over the entire area of the hole 8.

In FIG. 3, the scalar product is exactly zero at that point 20 most distant upstream, which lies at the edge of the hole 8 farthest upstream. The angle α between the transport direction vector 17 and the rotation direction vector 19, measured at point 20 in FIG. 3 is exactly 90 °. If you move along the hole 8 further down, i.e. in the direction of rotation 12, the angle between the direction vectors will increase and become an obtuse angle of more than 90 °, and the scalar product will be negative at the same time. The scalar product is not at any point or in any zone of the hole 8, however, is positive or the angle is not less than 90 °. Due to this, local excessive loading cannot occur even on one section of the hole 8, or in no area of the hole 8 a dangerous excess of the packing effect can occur.

This is the decisive difference from a purely radial arrangement, since the point 20 or edge 20 ′ with a radial arrangement of the extruder would have an angle α less than 90 °, and the areas of the hole 8 lying to the right next to the radial 11 or upstream or from the input side, would have a positive scalar product. Consequently, locally molten polymeric material could accumulate in these zones.

In FIG. 4, another alternative embodiment is shown in which the extruder 5 with two synchronous-action screws 6 vertically lying one above the other is offset a little further than in FIG. 3, but not yet tangentially, as in FIG. 1 and 2. In this case, as in FIG. 3, an imaginary backward extension of the longitudinal axis 15 of the screws 6 passes through the interior of the hopper 1 as a secant. As a result, when measuring in the direction of the periphery of the hopper 1, the opening 8 is wider than in the embodiment of FIG. 3. Also, the distance 18 is correspondingly greater than in FIG. 3, however, smaller than the radius 11. The angle α, measured at point 20, is about 150 °, so that compared with FIG. 3, the effect of the packing is reduced, which is preferable for certain susceptible polymers. The inner edge or the inner wall of the housing 16, which is right from the hopper 1, is adjacent to the hopper 1 tangentially, due to which, unlike in FIG. 3 there is no blunt transition edge. At this farthest downstream point of the hole 8, in FIG. 4 on the left, the angle is about 180 °.

Claims (20)

1. A device for pre-processing and subsequent transportation, plasticization or agglomeration of polymers, in particular thermoplastic polymer waste for recycling, containing a hopper (1) for the material to be processed, in which a mixing and / or grinding tool is installed with the possibility of rotation around the axis (10) ( 3) for mixing, heating and, if necessary, grinding the polymer material, moreover, in the side wall (9) of the hopper (1) in the height zone of the mixing and / or grinding tool (3) or near about the bottom of the mixing and / or grinding tool (3) there is a hole (8) through which the pre-treated polymer material is discharged from the hopper (1), at least one multi-screw conveyor (5) is provided for receiving the pre-processed material at least two screw conveyors, in particular plasticizing or agglomerating screws, mounted in the housing (16) rotatably mounted in the housing (16), the housing (16) having a feed on its end side (7) or in its side wall a hole (80) for the material captured by the screws (6), which is in communication with the hole (8), characterized in that the imaginary extension of the central longitudinal axis (15) of the conveyor (5) or the screw (6) closest to the feed hole (80) extends against directions (17) of transporting the conveyor (5) past the axis of rotation (10) without crossing it, moreover, the longitudinal axis (15) of the conveyor (5) or the screw (6) nearest to the feed hole (80) from the outlet side and in the direction (12) ) rotation or movement of the mixing and / or grinding tool (3) is shifted to the radiance (18) from the radial (11) of the hopper (1), which is parallel to the longitudinal axis (15) and directed outward from the rotation axis (10) of the mixing and / or grinding tool (3) in the direction (17) of conveyor conveyance (5), while the screws (6) are made synchronous action. 2. The device according to claim 1, characterized in that exactly two screws (6) are provided or the conveyor (5) is made in the form of a twin-screw conveyor of synchronous action. 3. The device according to p. 1 or 2, characterized in that the screws (6) are made cylindrical and parallel to each other or the conveyor (5) is made in the form of a parallel twin-screw conveyor. 4. The device according to p. 1 or 2, characterized in that the screws (6) are made conical or the conveyor (5) is made in the form of a conical twin-screw conveyor. 5. The device according to claim 1 or 2, characterized in that one of the screws (6) is longer, mainly by a length ≥3 times the diameter (d) of the screw (6). 6. The device according to p. 1 or 2, characterized in that the screws (6), at least in the area of the feed hole (80) are made tightly engaged or tangent. 7. The device according to claim 1 or 2, characterized in that the cross sections of the screws (6) lie vertically one above the other, and the screws (6) are located in the immediate area of the feed hole (80), in particular symmetrically with respect to its center, and equally far removed from the plane of the feed hole (80). 8. The device according to claim 1 or 2, characterized in that the cross sections of the screws (6) lie obliquely one above the other or horizontally next to each other and only the screw (6) closest to the feed hole (80) is located in the immediate area of the feed hole ( 80). 9. The device according to claim 1 or 2, characterized in that the screws (6) or the screw (6) closest to the feed hole (80), when viewed from the start of the screws (6) close to the feed hole or to the hopper, or from the feed hole (80) in the direction of the end or outlet of the conveyor (5), mounted or mounted rotatably clockwise. 10. The device according to claim 1, characterized in that for the conveyor (5) connected to the hopper (1), the scalar product of the rotation direction vector (19), which is oriented tangentially to the circle described by the radially extreme point of the mixing and / or grinding tool ( 3), or to the polymer material passing through the hole (8) and perpendicular to the radial (11) of the hopper (1) and indicates in the direction (12) of rotation and / or movement of the mixing and / or grinding tool (3), and the vector (17) conveyor transport directions (5) to each individual point or in the entire area of the hole (8) or immediately radially in front of the hole (8) is zero or negative. 11. The device according to p. 10, characterized in that the vector of the direction (19) of rotation of the radially extreme point of the mixing and / or grinding tool (3) and the vector (17) of the conveying direction of the conveyor (5) enclose an angle (α) ≥90 ° ≤ 180 °, measured at the intersection of both vectors (17, 19) on the upstream relative to the direction (12) of rotation or movement of the mixing and / or grinding tool (3) the edge of the hole (8) from the input side, in particular in the most remote upstream point (20) on this edge or hole (8). 12. The device according to p. 10, characterized in that the vector (19) of the direction (12) of rotation or movement and the vector (17) of the direction of transport of the conveyor (5) enclose an angle (β) of 170-180 °, measured at the intersection of both vectors (17, 19) in the center of the hole (8). 13. The device according to p. 1, characterized in that the distance (18) is greater than or equal to half the inner diameter of the housing (16) of the conveyor (5) or screw (6) and / or greater than or equal to 7, mainly greater than or equal to 20 the radius of the hopper (1) or the distance (18) is greater than or equal to the radius of the hopper (1). 14. The device according to p. 1, characterized in that the imaginary continuation of the longitudinal axis (15) of the conveyor (5) against the direction of transportation is located as a secant to the section of the hopper (1) and at least partially passes through the inner space of the hopper (1) ) 15. The device according to claim 1, characterized in that the conveyor (5) is connected tangentially to the hopper (1) or passes tangentially to its cross section or the longitudinal axis (15) of the conveyor (5) or auger (6) or the longitudinal axis of the nearest to the feed hole (80) of the screw (6) passes tangentially to the inner side of the side wall (9) of the hopper (1), moreover, the screw (6) is predominantly connected to the drive on its end side (7), and is made with the opposite end end the ability to transport material to the outlet located at the end end of the housing (16) bottom hole, in particular the extruder head. 16. The device according to p. 1, characterized in that the hole (8) directly and directly and without a significant gap, in particular without a transmitting section or a conveying screw, is connected to the feed hole (80). 17. The device according to claim 1, characterized in that the mixing and / or grinding tool (3) contains tools and / or knives (14), which in the direction (12) of rotation or movement have a grinding, cutting or heating effect on the polymer material moreover, the tools and / or knives (14) are made or located mainly on the installed tool holder for rotation, in particular parallel to the bottom (2), tool holder (13), in particular the carrier disk (13). 18. The device according to p. 1 or 17, characterized in that acting on the polymeric material, indicating in the direction (12) of rotation or movement of the front sections or front edges (22) of the mixing and / or grinding tools (3) or knives (14) differently executed, installed, curved and / or located in comparison with the rear or catching up in the direction (12) of rotation or movement of the sections. 19. The device according to p. 1, characterized in that the hopper (1) is made mainly in the form of a circular cylinder with a flat bottom (2) and a side wall (9) oriented vertically to it and / or mixing axis (10) and / or grinding tools (3) coincides with the central middle axis of the hopper (1), and / or the axis of rotation (10) or the central middle axis is oriented vertically and / or perpendicular to the bottom (2). 20. The device according to claim 1, characterized in that the lowest tool holder (13) or the lowest of the mixing and / or grinding tools (3) and / or hole (8) is located close to the bottom (2) at a small distance from it in particular in the area of the lower quarter of the height of the hopper (1), mainly at a distance of 10-400 mm from the bottom (2).

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