System for agglomerating and comminuting recycled plastic

Abstract

The invention relates to a system for agglomerating and comminuting recycled plastic, comprising an agglomerator which is designed to receive plastic waste and form same into elongated pin-shaped or sausage-shaped agglomerates in a pasty state and which is designed in the form of a disc agglomerator, comprising two discs which are profiled on the mutually facing surfaces thereof, can be moved relative to each other, and are arranged parallel and at a distance to each other and between which a disc intermediate area is formed. The agglomerator has an inlet opening for the recycled plastic, said opening leading into the central region of the disc intermediate area, and an outlet opening for the agglomerates. According to the invention, an annular comminutor is arranged downstream of the disc agglomerator, said annular comminutor having a plurality of comminuting tools which adjoin the outlet opening in an annular manner, wherein the comminuting tools are arranged radially outside of the disc intermediate area such that agglomerates exiting the outlet opening are comminuted into shorter pieces by means of the comminuting tools.

Description

[0001] "Plant for agglomerating and shredding plastic recyclate"

[0002] Description:

[0003] The invention relates to a system according to the preamble of claim 1.

[0004] Generic systems are known from practice.

[0005] For example, EP 2 817 131 B1 discloses a disc agglomerator in which plastic waste is processed into elongated strands of material, which are then crushed to form small particles. For the purposes of this proposal, both the plastic waste to be recycled in the disc agglomerator and the agglomerates produced in the disc agglomerator are referred to as plastic recyclate.

[0006] These particles can later be used as raw materials in the plastics processing industry, for example, they can be further processed in an extruder.

[0007] The invention is based on the object of improving a generic system such that it can be operated with low energy and economic expenditure. This object is achieved by a system according to claim 1. Advantageous embodiments are described in the subclaims.

[0008] In other words, the invention proposes comminuting the agglomerated material strands emerging from the outlet opening of the disc agglomerator and radially outward into small particles directly at the disc agglomerator. The outlet opening in a disc agglomerator is either the gap opening resulting from the distance between the two discs, i.e., an annular slot or gap between the two discs corresponding to the disc circumference, or an opening in a housing surrounding the two discs. According to the proposal, the material strands are comminutioned using a ring comminutor, i.e., with several comminution tools arranged on a circular line and closely adjacent radially inside or outside the outlet opening, and thus downstream of the disc agglomerator in the flow direction of the plastic recyclate.The agglomerated material strands emerging from the outlet opening of the disc agglomerator are accordingly brought against the crushing tools and are cut into shorter pieces, namely the desired small particles.

[0009] The proposed system design eliminates the need to transport the material strands via an additional conveyor system to a comminution device located at a distance from the disc agglomerator. Not only can the energy required for this conveyor system be saved, but the proposed system also avoids the cooling that would otherwise occur during transport of the material strands. Instead, the comparatively softer material strands, which have not yet cooled down, are crushed directly at the exit of the disc agglomerator, so that the energy required for this comminution is lower than the energy required to crush the same, but cooled and thus harder, material strands. Finally, the proposed system design also achieves a particularly compact design.

[0010] The crushing tools can, for example, be arranged directly on a disc of the disc agglomerator, or they can be mounted on a specially provided ring, which is therefore referred to as a crushing ring.

[0011] In one embodiment of the system, the shredding ring can be adjustable in the axial direction of the ring agglomerator, i.e. essentially transversely to the plane of the two discs, so that it opens or closes the annular outlet opening to varying degrees in the axial direction, i.e. can make the gap width of the outlet opening narrower or wider. Adjusting the gap width of the outlet opening is likely to be of minor importance during continuous operation of the ring agglomerator. However, it does offer the possibility of adapting the gap width to different plastic recyclates to be processed, so that in different production facilities where different types or compositions of plastic recyclates are processed, the shredding can be easily adjusted to the optimal gap width of the outlet opening.

[0012] Secondly, however, particularly when starting up the plant after an interruption in operation, this axial adjustment option offers the advantage of initially setting the outlet opening of the ring agglomerator to a small size with a corresponding gap width, or even closing the outlet opening completely and only gradually increasing the gap width as the disc agglomerator's operating time increases. Such an adjustable shredding ring can therefore also be referred to as a start-up ring. When the ring agglomerator is started up, there is initially only a small amount of plastic recyclate between the two discs, and depending on the material used, it may happen that instead of the desired agglomerated material strands, incomplete, flake-like agglomerates are initially formed, which complicates further processing in plants downstream of the agglomerator.By making the outlet opening smaller or even completely closed, the residence time of the material in the disc agglomerator can be extended until the desired material strands are formed.

[0013] The outlet opening can be enlarged based on in-house experience, for example, after a certain period of time. Alternatively, the outlet opening can be enlarged automatically, for example, by motorizing the shredding ring, depending on the current consumption, for example, if the disc agglomerator is driven by an electric motor and the current consumption reaches a certain value due to the increased rotational resistance between the discs. This can be an absolute value, i.e., a specific current of X amperes.

[0014] However, the specific value can also be a relative value, resulting, for example, from the temporal progression of the current consumption. For example, the current consumption can rise with increasing fill level if increasing amounts of plastic recyclate enter the space between the two discs. If less material exits the outlet opening per unit of time than plastic recyclate flows into the space because the outlet opening is partially or completely closed, this leads to an increase in the amount of plastic recyclate in the space. Due to the higher fill level and the longer residence time, the material is processed more intensively in the disc agglomerator and takes on higher temperatures due to external influences and internal friction.

[0015] The resulting softening of the material leads to a reduction in the rotational resistance of the disc agglomerator, so that the power consumption of the drive motor at least does not increase further and typically even decreases again. If the power consumption is monitored by an electronic system control system, the outlet opening can be automatically enlarged based on the current consumption curve. This is achieved by automatically controlling the drive means of the comminution ring and automatically moving the comminution ring in the axial direction. The agglomerated material in the disc agglomerator can now leave the disc agglomerator through the outlet opening in the form of the desired material strands, which are then divided into the desired shorter pieces in the comminution ring.

[0016] The possibility of completely or partially closing the outlet opening of the disc agglomerator during the start-up phase can be achieved, depending on the design of the disc agglomerator and its outlet opening, by an axial adjustment of the two discs relative to each other, by an adjustable start-up ring - with or without crushing tools - or by a movable slide or similar closure elements closing the outlet opening.

[0017] In a conventional manner, the disc agglomerator can be designed in such a way that not both discs rotate, but rather one disc remains stationary. This disc, known as the stator, has the inlet opening through which the plastic recyclate enters the space between the two discs. The other disc, known as the rotor, is rotatably mounted and driven. With this design, the shredding ring can be held non-rotatably on the stator. Initial practical tests have shown that excellent shredding can be achieved even when the shredding ring is stationary, since the rotor entrains the agglomerated material strands and moves them not only radially but also tangentially relative to the stator and, accordingly, to the shredding ring, allowing the shredding tools to act on the material strands.

[0018] In principle, the shredding tools can simply form a counterbearing against which the material strands emerging from the disc agglomerator collide, shearing them off and thus shredding them. In one embodiment, the shredding tools can be designed as knives, so that the shredding of the material strands can occur with as little resistance as possible and thus requires as little energy as possible.

[0019] The blades can advantageously be arranged at an angle of between 35° and 80° relative to the agglomerator axis, as far as the cutting edge of the blades is concerned. This achieves a pulling cut, which is advantageous in terms of energy consumption and also reduces the mechanical stress on the blades. With regard to these two aspects, the angle at which the cutting edges of the blades are aligned to the agglomerator axis can be between 45° and 60° in a configuration considered advantageous.

[0020] In one embodiment, the knives can each be arranged in the ring shredder so that they can be replaced. This enables quick and uncomplicated replacement of individual worn knives, or, if necessary, the replacement of one or all of the knives with ones with a differently designed cutting edge. In one embodiment, the knives can each be arranged in a knife holder that is replaceably held on the ring shredder. This also enables the replacement of individual or all of the knives as explained above. Furthermore, the knife holder can be designed as a stable element so that a narrow, delicate knife does not have to be handled separately. For example, the knife holder, which can have a greater material thickness than the knife itself, enables the knife to be screwed to the ring shredder with a high tightening torque of the fastening screw without endangering the knife.

[0021] Regardless of whether the knives are attached directly to the ring shredder or via a knife holder, they can be mounted in a radially adjustable configuration. This allows the width of the annular gap between the outlet opening and the knives to be adjusted, thus influencing the size of the shorter pieces produced.

[0022] In one embodiment, the shredding ring can have multiple receptacles designed to accommodate shredding tools, for example, by holding the knives themselves or the knife holders equipped with the knives in the receptacles. In this embodiment, the shredding ring can have such a large number of receptacles that in many practical applications, a corresponding number of knives is not required. Accordingly, in this system embodiment, not all receptacles are equipped with a shredding tool. The number of shredding tools used can vary depending on the plastic recyclate used or the desired size of the shorter pieces into which the agglomerated material strands are to be shredded.In this design, the receptacles that are not required and therefore not equipped with a shredding tool are covered with a cover element. This protects the receptacles themselves, for example, from contamination that could potentially complicate the subsequent installation of a shredding tool in this receptacle. Furthermore, personnel protection is achieved in terms of accident prevention by ensuring the system has the smoothest possible surface and avoiding a jagged outer surface of the shredding ring.

[0023] In one embodiment, it can be provided that the ring shredder not only has a row of shredding tools arranged in a ring on the stator of the disc agglomerator, but rather has a row of shredding tools arranged in a ring on each of the discs, so that the agglomerated material strands emerging radially outward from the outlet opening are shredded into short pieces by a shearing movement between the two different rows of shredding tools. The system therefore has first shredding tools arranged on a first circular line with a first diameter and connected to a first disc of the disc agglomerator, and second shredding tools arranged on a second circular line with a second diameter and connected to a second disc of the disc agglomerator.The first and second comminution tools are movable relative to one another, as the two disks of the disk agglomerator are movable relative to one another. The diameters of the first and second circular lines are different, so that the first and second comminution tools interact like scissors and comminute the agglomerated material strands between them. In this described embodiment of the system, it can be provided that the first and second comminution tools are each arranged on a retaining ring that is connected to the respective first and second disk of the disk agglomerator. Both retaining rings each have a free space designed as an annular groove, into which the comminution tools arranged on the respective other retaining ring can penetrate when comminution tools are adjusted in the axial direction of the disk agglomerator.For example, when the crushing tools arranged on the stator are adjusted axially toward the rotor, the crushing tools each engage the annular groove of the opposing retaining ring. Because they can be accommodated in the opposing retaining ring, the crushing tools can be designed long enough to ensure a shearing effect between the crushing tools across the entire gap width, even with a large outlet opening gap width.

[0024] The invention is explained in more detail below using purely schematic representations, whereby individual design features of a specific embodiment of a plant for agglomerating and shredding plastic recyclate are not limited to this embodiment, but can also be implemented in other configurations and / or in other combinations.

[0025] Fig. 1 is a perspective view of a plant for agglomerating and shredding plastic recyclate, with a first embodiment of a disc agglomerator,

[0026] Fig. 2 and 3 views of a first embodiment of a ring crusher, in a normal position

[0027] Fig. 4 and 5 views of the ring crusher of Fig. 2 and 3, in a starting position, Fig. 6 a perspective view of a crushing ring of the ring crusher of Fig. 2 to 5,

[0028] Fig. 7 is a vertical cross-section through a second embodiment of a disc agglomerator,

[0029] Fig. 8 is a perspective view of a longitudinal section through a second embodiment of a ring crusher in the starting position,

[0030] Fig. 9 is a view of the ring crusher of Fig. 8 in the normal position,

[0031] Fig. 10 is a perspective view of a longitudinal section through a third embodiment of a ring crusher in the starting position,

[0032] Fig. 11 is a view of the ring crusher of Fig. 10 in the normal position,

[0033] Fig. 12 a vertical cross section through a third embodiment of a disc agglomerator,

[0034] Fig. 13 is a vertical longitudinal section through the upper portion of the third embodiment in the starting position, and

[0035] Fig. 14 a vertical longitudinal section through the lower area of ​​the third embodiment in the starting position.

[0036] Fig. 1 shows a plant 1 for agglomerating and shredding plastic recyclate, which has a disc agglomerator 2. Fig. 1 shows the viewer the rear side of a first disc, referred to as stator 3, of the disc agglomerator 2, with a central inlet opening 4 through which the plastic recyclate is introduced into a space between the two discs. Through the inlet opening 4, the view falls on a rotationally driven second disc, referred to as rotor 5, of the disc agglomerator 2. By means of three stator actuating cylinders 6s, the stator 3 can be moved in the axial direction so that the gap width between the stator 3 and the rotor 5 can be changed. By means of three ring actuating cylinders 6r, each of which has an essentially cylindrical protective cover, a shredding ring can be moved in the axial direction, as will be explained in more detail later.

[0037] In the lower peripheral area of ​​the two discs of the disc agglomerator 2, a conveyor device 7 is connected to the disc agglomerator 2, so that the agglomerates produced in the disc agglomerator 2 can be transported by means of the conveyor device 7 in a conveying direction F to a downstream device. An exhaust connection 7a serves to remove gases produced during agglomeration from the agglomerate stream, so that unwanted gas entry, for example into a downstream extruder, can be reduced as much as possible.

[0038] Figs. 2 and 3 each show the central components of a disc agglomerator 2, namely the rotor 5, which can be connected to a drive shaft, and the stator 3, which is largely concealed by a ring shredder 8. The ring shredder 8 consists of a shredding ring 9 and several shredding tools 10, with the shredding ring 9 in turn being composed of three segments 11. In Figs. 2 and 3, the disc agglomerator 2 is in its normal position, which it normally assumes during operation, namely with a certain distance between the stator 3 and the rotor 5, so that a circumferential gap 12 is formed on the outer circumference of the disc agglomerator 2 between the two discs. In this normal position, the gap 12 forms an open, annular outlet opening 34 on its outer circumference between the two discs of the disc agglomerator 2.

[0039] The three ring actuating cylinders 6r allow the comminution ring 9, which is arranged radially outward on the lateral surface of the stator 3, to be moved in the axial direction and thus brought closer to or further away from the rotor 5, even if the stator 3 maintains its position. This allows the comminution ring 9 to be brought into the working position shown in Figs. 2 and 3, namely into a retracted position away from the rotor 5, in which the outlet opening 34 is open, so that the comminution tools 10 of the ring comminutor 8 are arranged radially outside the circumferential gap 12 and the outlet opening 34. The elongated agglomerates emerging from the outlet opening 34 between the stator 3 and the rotor 5 at the circumference of the gap 12 are captured by the comminution tools 10 and, assisted by the rotational movement of the rotor 5 and the inclined position of the comminution tools 10 shown in Figs. 2 and 3, are crushed in a pulling cut.

[0040] When the ring actuating cylinders 6r are extended, the comminution ring 9 of the ring comminutor 8 is pushed over the gap 12 and in this way the outlet opening 34 is closed, which is referred to as the starting position of the disc agglomerator 2 and has the effect that the material located in the disc agglomerator 2 between the stator 3 and the rotor 5 cannot escape radially outwards from the outlet opening 34 as quickly when the disc agglomerator 2 is started up, but can be held in the disc agglomerator 2 for a longer time and can be mechanically processed.Although direct contact between the stationary and rotating components of the disc agglomerator 2 is avoided, the minimal opening width of the outlet opening 34 and the required directional deflection that the material must take on its path radially outwards create a type of labyrinth seal with the comminution ring 9 moved into the start-up position, which seals the outlet opening 34 sufficiently tightly from a practical point of view.

[0041] The start-up process is shortened by closing the outlet opening 34, and the escape of insufficiently agglomerated material can be largely or even completely prevented. Therefore, in deviation from the illustrated embodiment and outside the scope of the present proposal, it can also be provided to use the comminution ring 9 without comminution tools 10, so that in this case it can be referred to as a start-up ring, which merely has the closing function of closing the outlet opening 34 when the disc agglomerator 2 starts up.

[0042] Figs. 4 and 5 show the central components of the disc agglomerator 2 of Figs. 2 and 3, but in a so-called starting position, in which the two discs are spaced closer together, so that there is practically no gap 12 between the stator 3 and the rotor 5. In particular, it can be seen from Fig. 4 that the rotor 5 is provided with a number of deflectors 14, which serve to convey plastic recyclate, which has reached behind the rotor 5 in the agglomerated or non-agglomerated state, radially outwards and to prevent it from reaching the drive shaft of the disc agglomerator 2.

[0043] Fig. 6 shows the ring shredder 8 separate from the other components of the disc agglomerator 2. The structure of the shredding ring 9, consisting of three segments 11, is visible. The shredding tools 10 each have a holder 15 and an interchangeable blade 16 arranged therein. The cutting edges of the blades 16 are each aligned at an angle of approximately 45° to the axis of the disc agglomerator 2, so that a pulling cut is achieved when, due to the rotational movement of the rotor 5, the agglomerates emerging from the gap 12 are guided in the direction of rotation against the blades 16. Because the agglomerates are carried along by the rotor 5 in the direction of rotation, the rotor 5 also provides the cutting energy required for cutting.

[0044] The holders 15 are fixed to the segments 11 by means of elongated holes in the radial direction so that the radial distance at which the knives 16 are located in front of the gap 12 can be adjusted. Each segment 11 has three so-called receptacles 17, namely mounting locations for comminution tools 10, and thus offers the possibility of mounting three comminution tools 10 on a segment 11. In the illustrated embodiment, only one comminution tool 10 is shown per segment 11, while the two remaining receptacles 17 are each protected against contamination and the ingress of plastic by means of a cover element 18 in order to enable problem-free mounting of a comminution tool 10 if necessary.

[0045] Fig. 7 shows a vertical section through the gap 12 of a disc agglomerator 2, so that the stator 3 is not visible, but rather the rotor 5 and its central opening for receiving a drive shaft are visible. On the surface of the rotor 5, a multitude of differently designed kneading bars 19 can be seen. These serve to mechanically treat, heat, and agglomerate the plastic recyclate entering the disc agglomerator 2 in cooperation with the stator 3, which also has a profiled surface, forming elongated agglomerates. The plastic recyclate migrates radially outward from the central inlet opening 4 and leaves the space between the two discs through the gap 12. In the embodiment of Fig. 7, the outlet opening 34 is also created on the outer circumference of the two discs, as a circumferential opening of the gap 12 between the stator 3 and the rotor 5.

[0046] 7 and 8, the agglomerates enter a ring shredder 8 which has shredding tools 10 which, in contrast to the embodiment in Figs. 2 to 6, are not designed as knives. Rather, the ring shredder 8 in Fig. 7 has two shredding rings 9 with different effective diameters. The shredding ring 9 shown on the right in Fig. 8 is referred to as the outer shredding ring 9 because its shredding tools 10 are located on a circular line with a comparatively larger diameter, and is connected to the stator 3. In the so-called inner shredding ring 9, shown on the left in Fig. 8, the shredding tools 10 are located on a circular line with a smaller diameter than the outer shredding ring 9.The inner comminution ring 9 is connected to the rotor 5, thus achieving a relative movement between the two comminution rings 9. Since the comminution tools 10 of the two comminution rings 9 are arranged on circular lines of different radii, the inner and outer comminution tools 10 interact to produce a cutting effect, breaking up the elongated agglomerates through their combined shearing action. A rhomboid cross-sectional shape of the comminution tools 10 promotes this shearing action.

[0047] At a radial distance from the two discs of the disc agglomerator 2, a housing 20 extends outside the illustrated rotor 5, so that the agglomerates emerging through the gap 12 and reduced into shorter pieces in the ring crusher 8 can be pneumatically removed. For this purpose, the housing 20 is connected to a pneumatic conveying line 21, as shown in Fig. 7. Apart from the fact that a fan (not visible in the drawing) generates an air flow in the conveying line 21, the direction of rotation of the rotor 5 also generates or supports an air flow that transports the agglomerates reduced into shorter pieces through the conveying line 21 in a conveying direction F indicated by an arrow.

[0048] Fig. 8 shows a section through the upper circumferential region of the disc agglomerator 2 of Fig. 7. The stator 3 and the rotor 5 can be seen within the housing 20. Similar to the exemplary embodiment in Figs. 4 and 5, the exemplary embodiment in Fig. 8 is also in its starting position. In the exemplary embodiment in Figs. 7 and 8, the starting position is achieved by axially adjusting the stator 3 using the disc adjusting cylinders 6s, so that the gap 12 on the outer circumference of the two discs is closed by adjusting the stator 3 axially up to the rotor 5. Accordingly, the two comminution rings 9 of the ring comminutor 8 also bear against one another. On their mutually facing end faces, both comminution rings 9 are each provided with a circumferential annular groove 22, which serves to accommodate the comminution tools 10 of the opposite comminution ring 9.A space between the discs 23 tapers down to a gap 12, and in the starting position shown, both the gap 12 and the outlet opening 34 on its outer circumference are considered to be practically closed, even if the stationary and rotating components of the disc agglomerator 2 do not touch each other, but rather have a minimal distance from each other.

[0049] Because the gap 12 is completely open as in Fig. 8 or, in contrast to the embodiment of Fig. 8, possibly slightly open, the plastic recyclate is held in the space between the discs when the disc agglomerator 2 is put into operation, i.e. when it is “started up”. Losses in the form of plastic recyclate that is not sufficiently agglomerated and is therefore not suitable for further processing can be reduced or even completely avoided in this way. Only when the material that has entered the space between the discs between the stator 3 and the rotor 5 during start-up has sufficiently agglomerated is the stator 3 removed from the rotor 5 by means of the adjusting cylinders 6r and the gap 12 opened wide enough that agglomerates can escape and enter the ring shredder 8. Fig. 9 shows the embodiment of Fig.8 after the disc agglomerator 2 has been started up, when it has assumed its normal position and the space between the discs has been enlarged by adjusting the stator 3, and the gap 12 and the outlet opening 34 have been opened. It can be seen how the comminution tools 10, arranged at different radii, interact with each other in a shearing manner and have emerged from the annular groove 22 of the respective opposite comminution ring 9.

[0050] Fig. 10 shows a situation similar to Fig. 8, wherein in Fig. 10, a disc space 23 between the stator 3 and rotor 5 is closed at the outer circumference by means of a disc actuating cylinder 6s, since the disc agglomerator 2 shown in Fig. 10 is in its starting position. In this embodiment, the comminution tools 10 are shown as cylindrical pins, which have a comminution-effective cutting or inclined surface outside their respective comminution ring 9.

[0051] Fig. 11 shows a situation similar to Fig. 9 for the embodiment of Fig. 10, in which the gap 12 is opened by corresponding adjustment of the stator 3 and the disc agglomerator 2 assumes its normal position.

[0052] Fig. 12 shows a view similar to Fig. 7 of a further embodiment of a disc agglomerator 2 and its rotor 5, but the kneading bars 19 of the rotor 5 are configured differently than in Fig. 7. The housing 20 is also designed differently in that it runs at a comparatively smaller distance around the two discs of the disc agglomerator 2. A ring shredder 8 is designed such that it interacts with the housing 20. The ring shredder 8 does not have a physically realized shredding ring 9, but rather a plurality of shredding tools 10 that are arranged on a circular line and thus form a shredding ring. In the embodiment of Fig. 12, no pneumatic conveying of the agglomerates cut into shorter pieces is provided. Instead, the elongated agglomerates emerging from the gap 12 are conveyed by means of the shredding tools 10.Unlike the deflectors 14 of Fig. 7, the comminution tools 10 in Fig. 12 are not arranged on the rear side of the rotor 5, but are radially connected to the outer circumference of the rotor 5. However, similar to the deflectors 14 in Fig. 7, they also serve to clear the space inside the housing 20 into which plastic material enters and to transport the captured material.

[0053] By means of the comminution tools 10, the captured material is conveyed within the housing 20 to a housing opening 24, which forms the outlet opening 34 of the disc agglomerator 2. There, a shearing action to comminute the agglomerates occurs not with the aid of a second comminution ring, but rather in interaction with the edge of the housing 20 surrounding the housing opening 24. The elongated agglomerates are not crushed into separate, shorter pieces, but are literally shovelled into the space adjacent to the housing opening 24 and thus crushed. For this purpose, the comminution tools 10 have a front side acting on the material, which deviates from a purely radial orientation to the rear at a suitable angle.In this way, a spatula effect is achieved with which the material is introduced into a conveying line 21 which, in the illustrated embodiment, is directly connected to the housing 20.

[0054] In contrast to the embodiment of Fig. 7, the conveyor line 21 of Fig. 12 does not serve for the pneumatic transport of the material, but rather has a conveyor screw 25 that transports the material in the conveying direction F. To ensure that the conveyor screw 25 is well filled, in this embodiment the conveying direction F runs opposite to the direction in which the rotor 5 moves in the region of the housing opening 24. The conveyor line 21 can, for example, be the intake screw of an extruder or a short transfer screw that in turn connects to an extruder screw.In both cases, the temperature losses of the material can be kept as low as possible, so that in an energetically particularly favorable design of the plant 1, the plastic material, which is initially agglomerated and then cut into shorter pieces, can be further processed in an extruder which is connected downstream of the disc agglomerator 2 by the shortest possible route.

[0055] The conveyor line 21 has an opening where it connects to the housing 20 of the disc agglomerator 2. Deviating from the illustrated embodiment, a closure element can be arranged between the housing 20 and the conveyor line 21, for example in the form of a slide valve arranged on the housing 20 or on the conveyor line 21. Similar to the possibility of closing the outlet opening 34 by means of an axially adjustable comminution ring 9 or an axially adjustable stator 3, the closure element can also be used to initially hold material in the disc agglomerator 2 during the start-up phase of the disc agglomerator 2 until the material is sufficiently agglomerated.

[0056] Furthermore, not shown in the embodiment of Fig. 12, a suction connection can be arranged in the region of the transition from the housing 20 to the conveyor line 21 in order to be able to suck out gases produced during agglomeration before these gases can reach the conveyor screw 25.

[0057] Deviating from the embodiment shown in Fig. 12 and outside the present proposal, it is possible to dispense with the scraper-like comminution tools 10 and to have the housing 20 extend radially outwardly tightly around the discs of the disc agglomerator 2. The smallest possible distance between the housing 20 and the discs ensures friction-free and trouble-free operation of the disc agglomerator 2, but also prevents larger accumulations of agglomerates from radially outwardly moving between the discs. The pressure that builds up in the space 23 between the discs due to the material being conveyed into the disc agglomerator 2, as well as the centrifugal forces generated by the rotor 5 in the disc agglomerator 2 and the conveying effect of the kneading bars 19 cause the agglomerates to push radially outward.

[0058] Fig. 13 shows a section through the upper region of the disc agglomerator 2 of Fig. 12, which is in its starting position, so that the gap 12 and the outlet opening 34 on the outer circumference of the disc space 23 are closed. The section in Fig. 13 runs through a comminution tool 10 of the ring comminutor 8. By means of various screws 26, both the housing 20 is fastened to the stator 3 and the comminution tools 10 are fastened to the rotor 5. Behind the rotor 5, a rotor holder 27 is shown, which is provided with a sealing ring 28 on its outer circumference.

[0059] The sealing ring 28 has a thread profile 30, namely a helical groove, extending toward a space 29 that extends radially outside the gap 12 in a ring around the discs of the disc agglomerator 2, as well as on its radial outer side, toward the housing 20. The pitch of this thread profile 30 is coordinated with the direction of rotation of the rotor 5 in such a way that any material that has penetrated into the helical groove is conveyed back into the space 29.

[0060] Furthermore, sealing air is used to counteract the penetration of plastic into the area of ​​the thread profile 30: the housing 20 is provided with an air connection 31 to which a compressed air line can be connected. The compressed air flows into a circular sealing air channel 32 and from there into the area of ​​the thread profile 30, forcing any material located between the sealing ring 28 and the housing 20 back into the space 29.

[0061] Fig. 14 shows the lower circumferential area of ​​the disc agglomerator 2 of Figs. 12 and 13. The section runs in the longitudinal direction of the axis of rotation around which the rotor 5 rotates, and thus transversely to the conveyor screw 25. On the inside of the tubular housing of the conveyor line 21, the conveyor line 21 has several retaining grooves 33, each having a wedge cross-section. They serve to prevent the material, which has been introduced into the conveyor line 21 through the housing opening 24 with the aid of the comminution tools 10, from rotating together with the conveyor screw 25, so that a translational movement of the material within the conveyor line 21 can be achieved by means of the conveyor screw 25 with the greatest possible conveying efficiency.

[0062] Reference symbol:

[0063] Plant disc agglomerator stator

[0064] Inlet opening rotor

[0065] 6s = Stator actuating cylinder 6r = Ring actuating cylinder Conveying device, 7a = Suction connection F = Conveying direction Ring shredder Shredding ring Shredding tool Segment Gap Deflector Holder Blade Receptacle Cover element Kneading bars Housing Conveying line Ring groove Disc space Housing opening Conveyor screw Screw Rotor receptacle Sealing ring Space

[0066] Thread profile Air connection Sealing air duct Retaining groove Outlet opening

Claims

Claims:

1. Plant (1) for agglomerating and crushing plastic recyclate, comprising an agglomerator, o designed to receive plastic waste and form it into elongated, cone-shaped or sausage-shaped agglomerates in a doughy state, o and designed as a disc agglomerator (2), with two discs, ■ which are profiled on their mutually facing surfaces, ■ are movable relative to each other, ■ are arranged parallel to each other and at a distance from each other ■ and create a disc space (23) between them, o and which has an inlet opening (4) for the plastic recyclate, which opens into the central area of ​​the disc space (23), o and which has an outlet opening (34) for the agglomerates, characterized in that the disc agglomerator (2) is equipped with a ring shredder (8) is downstream, which has several comminution tools (10) arranged in a ring shape adjacent to the outlet opening (34), wherein the comminution tools (10) are arranged radially outside the disc space (23) such that agglomerates emerging from the outlet opening (34) are cut into shorter pieces by means of the comminution tools (10).

2. System according to claim 1, characterized in that the outlet opening (34) is arranged in the outer circumference of the disc space (23), and the ring crusher (8) has a crushing ring (9) carrying the crushing tools (10), which is arranged radially outside the outlet opening (34).

3. System according to claim 2, characterized in that the comminution ring (8) is movable in the axial direction of the ring agglomerator (2) in such a way that it selectively opens or closes the outlet opening (34) to different extents.

4. System according to claim 3, characterized in that one of the two disks of the ring agglomerator (2) is arranged as a stator (3) in a rotationally fixed manner and has the inlet opening (4), and the second disk is rotatably mounted as a rotor (5), wherein the comminution ring (8) is held rotationally fixed to the stator (3).

5. Plant according to one of the preceding claims, characterized in that the comminution tools (10) are designed as knives (16).

6. System according to claim 5, characterized in that the knives (16) are aligned at an angle to the axis of the disk agglomerator (2) which is between 35° and 80°.

7. System according to claim 6, characterized in that the angle is between 45° and 60°.

8. Plant according to one of claims 1 to 4, characterized in that the comminution tools (10) are designed as pins with an inclined surface.

9. Plant according to one of claims 1 to 4, characterized in that the comminution tools (10) have a rhomboid cross-section.

10. Plant according to one of the preceding claims, characterized in that the comminution tools (10) are each interchangeable.

11. Plant according to one of the preceding claims, characterized in that the crushing tools (10) are each arranged in a holder (15) which is replaceable.

12. Plant according to one of the preceding claims, characterized in that the comminution tools (10) are each adjustable in a radial direction such that their radial distance to the outlet opening (34) is adjustable.

13. Plant according to one of the preceding claims, characterized in that the ring crusher (8) has first crushing tools (10) which are arranged on a first circular line with a first diameter and are connected to a first disk of the disk agglomerator (2), and has second comminution tools (10) arranged on a second circular line with a second diameter and connected to a second disk of the disk agglomerator (2), wherein the first and second comminution tools (10) are movable relative to each other, and the diameters of the first and second circular lines are different, such that the first and second comminution tools (10) interact in a scissor-like manner.

14. Plant according to claim 13, characterized in that the first and second comminution tools (10) are each arranged on a comminution ring (9) which is connected to the respective first or second disk of the disk agglomerator (2), wherein the two comminution rings (9) each have a free space designed as an annular groove (22) which is intended to accommodate the comminution tools (10) located on the respective other comminution ring (9).

15. System according to one of claims 2 to 14, characterized in that the comminution ring (9) has a plurality of receptacles (17) which are intended for mounting comminution tools (10), wherein a comminution tool (10) is arranged in at least one receptacle (17) and at least one receptacle (17) is free of a comminution tool (10) and is covered by means of a cover element (18).

16. Plant according to one of claims 2 to 15, characterized in that, that the comminution ring (9) is formed by several segments (11). System according to claim 1, characterized in that a housing (20) extends annularly around the outside of the discs of the disc agglomerator (2) and has the outlet opening (34) in the form of a housing opening (24) which connects to a conveying line (21), and that the comminution tools (10) extend radially within the outlet opening (34) effectively conveying into the space (29) between the housing (20) and the discs of the disc agglomerator (2), such that they convey agglomerates located in this space to the housing opening (24). System according to one of the preceding claims, characterized in that a conveying line (21) with a screw conveyor (25) connects to the disc agglomerator (2). The system according to claim 18, characterized in that the conveying line (21 ) is designed as an extruder screw or as a transfer screw connected to an extruder.A system according to one of the preceding claims, characterized in that a thread profile (30) with a helical groove extends between a rotatable disk, designated as rotor (5), and the housing (20) of the disk agglomerator (2), wherein the pitch of the thread profile (30) is adapted to the direction of rotation of the rotatable disk in such a way that between the rotor (5) and the housing. (20) material that has penetrated is conveyed back. System according to one of the preceding claims, characterized in that a sealing air channel (32) runs circumferentially between a rotatable disk, designated as rotor (5), and a housing (20) of the disk agglomerator (2), which is in flow communication with an air connection (31) opening outside the housing (20), wherein an air gap between the rotor (5) and the housing (20) connects at one end to the sealing air channel (32) and at the other end to a space (29) into which the outlet opening (34) opens.

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