Abstract
A toothed disc cleaner includes a first cleaning tool and a second cleaning tool that face each other and a rotary drive configured to rotationally drive at least one of the first and second cleaning tools. The first and second cleaning tools each include a working surface including a plurality of cleaning teeth, and an annular working gap delimited between the working surfaces and structured for pre-cleaning the plastic waste. An inlet opens centrally into the working gap and a feed apparatus is structured to feed the plastic waste through the inlet. An outlet is structured to discharge the pre-cleaned plastic waste in the working gap. A width of the working gap narrows outward from the inlet in a first section and is kept constant in a second section arranged radially outside of the first section. The cleaning teeth of the working surfaces mesh together in a mutually spaced manner.
Claims
1-14. (canceled)
15. A toothed disc cleaner for pre-cleaning pre-comminuted plastic waste, during a process of plastic recycling, comprising: a first cleaning tool and a second cleaning tool, wherein the first and second cleaning tools face each other; a rotary drive configured to rotationally drive at least one of the first and second cleaning tools; wherein the first and second cleaning tools are each structured to comprise: a working surface including a plurality of cleaning teeth, and an annular working gap delimited between the working surfaces of the first and second cleaning tools and configured for pre-cleaning the plastic waste; an inlet configured to opens centrally into the working gap; a feed apparatus configured to feed the plastic waste to be cleaned through the inlet; and an outlet provided on an outer edge of the working gap configured to discharge the pre-cleaned plastic waste in the working gap, wherein a width of the working gap narrows radially outward starting from the inlet in a first section, wherein the width of the working gap is constant in a second section arranged radially outside of the first section, and wherein the cleaning teeth of the working surfaces of the first and second cleaning tools mesh together in a mutually spaced manner.
16. The toothed disc cleaner according to claim 15, wherein the second section directly follows from the first section.
17. The toothed disc cleaner according to claim 15, wherein the second section extends to an outer edge of the working gap.
18. The toothed disc cleaner according to claim 15, wherein the working surfaces of the first and second cleaning tools comprise a cone shape in the first section and parallel surfaces in the second section.
19. The toothed disc cleaner according to claim 15, wherein the plurality of cleaning teeth are arranged on the first and second sections of the working surfaces of the first and second cleaning tools that form the first section at a greater distance from each other than on the surface sections of the working surfaces of the first and second cleaning tools that form the second section.
20. The toothed disc cleaner according claim 15, wherein each of the plurality of cleaning teeth comprises a flank in a direction of rotation and that comprises an angle of between 30and 60relative to a respective working surface.
21. The toothed disc cleaner according to claim 15, wherein each of the plurality of cleaning teeth comprises a flank in a direction opposite to a direction of rotation and arranged at an angle of between 70and 90relative to a respective working surface.
22. The toothed disc cleaner according to claim 15, wherein at least one radially outer lateral flank of the plurality of cleaning teeth is configured obliquely with respect to a respective working surface.
23. The toothed disc cleaner according to claim 22, wherein mutually opposing lateral flanks of meshing cleaning teeth are mutually spaced in parallel.
24. The toothed disc cleaner according to claim 15, wherein the first and second cleaning tools are comprised of stainless steel cast parts.
25. The toothed disc cleaner according to claim 15, wherein at least one of the first and second cleaning tools comprises a cleaning disc.
26. The toothed disc cleaner according to claim 25, wherein the inlet opens into the working gap in an axial direction of the at least one cleaning disc.
27. The toothed disc cleaner according to claim 15, wherein the feed apparatus comprises a liquid supply apparatus configured to feed a liquid directly into the feed apparatus.
28. The toothed disc cleaner according to claim 15, further comprising a liquid supply apparatus configured to supply a liquid directly into the working gap.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] One exemplary embodiment of the invention is explained below in greater detail using figures.
[0035] FIG. 1 schematically illustrates a perspective view of an embodiment of a cleaning disc of a toothed disc cleaner.
[0036] FIG. 2 schematically illustrates a plan view of the embodiment of the cleaning disc from FIG. 1.
[0037] FIG. 3 schematically illustrates a sectional view along an embodiment of a toothed disc cleaner.
[0038] FIG. 4 schematically illustrates two views of an embodiment of the cleaning disc of the toothed disc cleaner.
[0039] FIG. 5 schematically illustrates a partial sectional view of an embodiment of a toothed disc cleaner.
[0040] FIG. 6 schematically illustrates the embodiment of the toothed disc cleaner according to FIG. 5 with an embodiment of a feed apparatus for feeding plastic waste to be cleaned.
[0041] FIG. 7 schematically illustrates the embodiment of the toothed disc cleaner according to FIG. 5 with an embodiment of a feed apparatus for feeding plastic waste to be cleaned.
[0042] FIG. 8 schematically illustrates the embodiment of the toothed disc cleaner according to FIG. 5 with an embodiment of a feed apparatus for feeding plastic waste to be cleaned.
[0043] FIG. 9 schematically illustrates a sectional view of an embodiment of a toothed disc cleaner with an embodiment of an outlet.
[0044] If not otherwise specified, the same reference signs denote the same objects in the figures.
DETAILED DESCRIPTION OF THE INVENTION
[0045] In FIGS. 1 and 2, a cleaning tool 10 of a toothed disc cleaner according to some embodiments of the invention is represented, in the present case a circularly annular cleaning disc 10 which may, for example, also be constructed from multiple circular ring segments. The cleaning disc 10 comprises a circularly annular working surface 12 on which a large number of cleaning teeth 14 are arranged. At the center, the cleaning disc 10 forms an inlet 16 for plastic waste to be pre-cleaned, for example plastic flakes from pre-comminuted plastic films. An outlet 18 for the pre-cleaned plastic waste is formed on the outer edge of the cleaning disc 10. A feed apparatus for feeding the plastic waste to be cleaned is connected to the inlet. The plastic waste may be fed, for example, together with a process liquid, such as water.
[0046] In FIG. 3, the cleaning disc 10 shown in FIGS. 1 and 2 is represented as a lower cleaning disc 10 together with an upper cleaning tool 20, in the present case an upper cleaning disc 20. The upper cleaning disc 20 is also configured circularly annularly and comprises a circularly annular working surface 22. Again, there are a large number of cleaning teeth 24 on the working surface 22 of the upper cleaning disc 20. At least one of the cleaning discs 10, 20 can be driven in rotation about the axis thereof by means of a rotary drive, such that a corresponding relative rotation between the cleaning discs 10, 20 is produced. The upper cleaning disc 20 is largely identical to the lower cleaning disc 10, with the difference that the rows of teeth formed from the cleaning teeth 24 are in each case radially offset with respect to the rows of teeth of the lower cleaning disc 10 formed from the cleaning teeth 14, such that the cleaning teeth 14 and 24 mesh together in a mutually spaced manner, as shown in FIG. 3. FIG. 3 also shows that mutually opposing lateral flanks 26, 28 of the meshing cleaning teeth 14, 24 are mutually spaced in parallel. It can also be seen that the lateral flanks 26 of the cleaning teeth 14 and the lateral flanks 28 of the cleaning teeth 24 are in each case designed mirror-symmetrically and are arranged obliquely, for example at an angle of between 10and 30, with respect to the working surface 12 and 22 bearing the cleaning teeth 14 and 24, respectively.
[0047] It is also particularly clear from FIG. 3 that the working surfaces 12 and 22 of the cleaning discs 10 and 20, in a first section, extend radially outward conically relative to each other starting from the inlet 16, such that the working gap formed between the working surfaces 12, 22 narrow radially outward starting from the inlet 16 in this first section. In a second section following on from the first section and continuing up to the outlet 18, the working surfaces 12 and 22 of the cleaning discs 10 and 20 are arranged in parallel with each other, such that the width of the working gap in this second section is constant. In FIG. 2, for illustrative purposes, the circular separation line between the radially inner first section in FIG. 2 and the radially outer second section is drawn in at the reference sign 30. It can also be seen in FIGS. 1 and 2 that the cleaning teeth 14 on the surface section of the working surface 12 forming the first section are arranged at a greater distance from each other than in the outer surface section of the working surface 12 forming the second section. The tooth density of cleaning teeth 14 is thus lower in the first section than in the second section. This is also the case for the upper cleaning disc 20.
[0048] The configuration of the toothed disc cleaner according to the invention shall be explained in more detail based on FIG. 4. Firstly, the cone angle 32 of the conical arrangement of the working surfaces 12 and 22 in the first section is represented in the right-hand view of FIG. 4, in which only the lower cleaning disc 10 is represented in section. The left-hand view in FIG. 4 is a sectional representation along the line A-A in the right-hand view of FIG. 4. In particular, one of the cleaning teeth 14 is shown there in a sectional view, wherein the direction of rotation of the cleaning disc 10 extends from left to right in the left-hand representation of FIG. 4. A flank 34 of the cleaning tooth 14 that is leading in the course of the relative rotation between the cleaning discs 10, 20 is arranged at an angle 36 of between 30and 60, in the present case approximately 45, with respect to the working surface 12. A flank 38 of the cleaning tooth 14 that is trailing in the course of the relative rotation between the cleaning discs 10, 20 is arranged at an angle 40 of between 80and 90, in the present case approximately 85, with respect to the working surface 12. The crown surface 42 of the cleaning tooth 14 may be in parallel with the working surface 12.
[0049] In some embodiments, edges between the various surfaces of the cleaning tooth 14, in particular the leading and trailing flanks 34, 38 and the crown surface 42 and/or between the leading and trailing flanks 34, 38 and the lateral flanks 26 and/or between the lateral flanks 26 and the crown surface 42 may be rounded. All cleaning teeth 14 and 24 may be designed as represented in FIG. 4 by way of example for one of the cleaning teeth 14. In some embodiments, the cleaning discs 10, 20 can, in each case, be produced as a stainless steel cast part.
[0050] In FIG. 5, cleaning discs 10, 20, which may, for example, be configured as explained with reference to FIG. 1 to 4, are arranged in a cleaner housing 44 so as to be rotatable relative to each other. During operation, a rotary drive 46 may, for example, drive the cleaning disc 20 in rotation about a rotary shaft 48, such that the cleaning discs 10, 20 perform a rotation relative to each other. The working gap between the cleaning discs 10, 20 can be set via an adjusting apparatus 50 comprising an adjusting drive 52 and an adjusting element 54.
[0051] Various possibilities for feeding plastic waste to be pre-cleaned into the toothed disc cleaner will be explained based on FIGS. 6 to 8. In FIG. 6, the feed system comprises a feed screw 58 which is driven via a worm drive 56 and to which plastic waste 62 to be pre-cleaned is supplied on one side via an inlet opening 60 and to which a cleaning liquid 66, such as water, is supplied on the other side by means of a pump 64. The cleaning liquid can, in principle, be added via a screw feed, also via multiple inlets, into the feed screw 58 downstream of the inlet, via a hollow shaft of the feed screw 58 and/or via feed nozzles in the cleaner housing 44. The feed screw 58 conveys the plastic waste 62 together with the cleaning liquid 66 centrally into the working gap formed between the cleaning discs 10, 20. The pre-cleaned plastic waste is discharged for further processing via the outlet 18, as represented in FIG. 6 at the reference sign 68.
[0052] The exemplary embodiment according to FIG. 7 differs from the exemplary embodiment according to FIG. 6 merely in that, instead of the feed screw 58, a feed hopper 70 is provided which comprises, on the upper edge thereof, multiple feed nozzles 72 arranged, for example, so as to be distributed at regular intervals. Cleaning liquid 66 supplied by the pump 64 is fed into the feed hopper 70 via the feed nozzles 72, for example in each case as a liquid jet onto an inner wall of the feed hopper 70, in which the supplied plastic waste 62 is located. The plastic waste 62 together with the cleaning liquid 66 is supplied via a connection 74 again centrally into the working gap between the cleaning discs 10, 20. Such a feed apparatus is known, for example, from EP3 423 203 B1.
[0053] In the exemplary embodiment according to FIG. 8, a feed tank 76 with a stirring apparatus 78 arranged therein is provided, into which the plastic waste 62 and the cleaning liquid 66 are supplied. The plastic waste 62 is stirred with the cleaning liquid 66 in the feed tank 76. The plastic waste 62 mixed with the cleaning liquid 66 is supplied via a pump 80 again centrally into the working gap between the cleaning discs 10, 20, as illustrated in FIG. 8 at 82.
[0054] By way of example, FIG. 9 shows an outlet of a toothed disc cleaner according to the invention, wherein only the cleaner housing 44 of the toothed disc cleaner is represented in section with the outlet in FIG. 9. The design represented in FIG. 9 corresponds, for example, to the design described in EP 3 057 751 B1. The exemplary embodiment according to FIG. 9 can be combined with any of the above-explained exemplary embodiments.
[0055] In the example represented, an outlet pipe 84 follows on from the outlet 18 of the toothed disc cleaner tangentially with respect to the working gap between the cleaning discs 10, 20. The outlet pipe 84 may be connected directly via a flange 86 or via a further pipe to a separating apparatus, in which the pre-cleaned plastic is separated from the impurities abraded in the working gap. In the example shown, at the end of the outlet pipe 84 that is remote from the flange 86 or else separating apparatus, a nozzle pipe 88 is connected to a pump 90, in particular a liquid pump 90, for example a water pump 90, such as a centrifugal pump.
[0056] During operation of the toothed disc cleaner, the plastic pre-cleaned in the working gap enters the outlet pipe 84 via the outlet 18 together with abraded impurities and the cleaning liquid on account of a centrifugal force. At the same time, liquid, such as water, is fed by means of the liquid pump 90 through the nozzle pipe 88, in the conveying direction of the suspension coming out of the working gap to the separating apparatus, and into the outlet pipe 84 in the form of a directed liquid jet, as illustrated in FIG. 9 at the reference sign 92. The directed liquid jet thus extends tangentially to the working gap, like the outlet pipe 84. The liquid jet transports the mixture of cleaning liquid and pre-cleaned plastic as well as abraded impurities in the outlet pipe 84 further to the separating apparatus, as illustrated in FIG. 9 at the reference sign 94. In the process, the liquid jet exerts a suction effect on the working gap as per the principle of a jet pump, such that the suspension of pre-cleaned plastic, abraded impurities, and cleaning liquid is sucked out of the working gap and into the outlet pipe 84. At the same time, the discharge consistency, i.e. the consistency in the outlet pipe 84, can be set in a suitable manner by means of the liquid jet. A solids pump is therefore not required, nor is a pump sump.
LIST OF REFERENCE SIGNS
[0057] 10 Cleaning disc [0058] 12 Working surface [0059] 14 Cleaning teeth [0060] 16 Inlet [0061] 18 Outlet [0062] 20 Cleaning disc [0063] 22 Working surface [0064] 24 Cleaning teeth [0065] 26 Lateral flanks [0066] 28 Lateral flanks [0067] 30 Separating line [0068] 32 Cone angle [0069] 34 Leading flank [0070] 36 Angle [0071] 38 Trailing flank [0072] 40 Angle [0073] 42 Crown surface [0074] 44 Cleaner housing [0075] 46 Rotary drive [0076] 48 Rotary shaft [0077] 50 Adjusting apparatus [0078] 52 Adjusting drive [0079] 54 Adjusting element [0080] 56 Worm drive [0081] 58 Feed screw [0082] 60 Inlet opening [0083] 62 Plastic waste [0084] 64 Pump [0085] 66 Cleaning liquid [0086] 68 Arrow [0087] 70 Feed hopper [0088] 72 Feed nozzles [0089] 74 Connection [0090] 76 Feed tank [0091] 78 Stirring apparatus [0092] 80 Pump [0093] 82 Arrow [0094] 84 Outlet pipe [0095] 86 Flange [0096] 88 Nozzle pipe [0097] 90 Pump [0098] 92 Arrow [0099] 94 Arrow
