TREATMENT ELEMENT FOR TREATING MATERIAL BY MEANS OF A SCREW MACHINE

Abstract

A treatment element for treating material by means of a screw machine comprises a conveying section and a melting section. The melting section is arranged downstream of the conveying section in a conveying direction and is connected in one piece with the conveying section. This reduces wear and increases the service life.

Claims

1. A treatment element for treating material by means of a screw machine comprising a conveying section and a melting section, which is arranged downstream of the conveying section in a conveying direction, and which is connected in one piece with the conveying section.

2. The treatment element according to claim 1, wherein the melting section comprises a number N of kneading disks, wherein: 1?N?7.

3. The treatment element according to claim 1, wherein the melting section comprises at least two kneading disks which are arranged one after the other in the conveying direction, and at least one of a respective first side and a respective second side of the at least two kneading disks have an offset angle c relative to one another, wherein: 0??c?90?.

4. The treatment element according to claim 1, wherein the melting section comprises at least one kneading disk which is twisted between a first side and a second side. The treatment element according to claim 4, wherein the at least one kneading disk has a twist angle d between the first side and the second side, wherein: 0?<d?30?.

6. The treatment element according to claim 4, wherein the at least one kneading disk has a pitch P.sub.A and an outer diameter D.sub.AA, wherein: 5?P.sub.A/D.sub.AA?10.

7. The treatment element according to claim 4, wherein the melting section comprises at least two kneading disks which are arranged one after the other in the conveying direction, and a first side of a kneading disk arranged downstream has an offset angle e relative to a second side of a kneading disk arranged upstream, wherein: 5??e?70?.

8. The treatment element according to claim 1, wherein the melting section comprises at least one kneading disk having a width L.sub.A and an outer diameter D.sub.AA, wherein: 0.1<L.sub.A/D.sub.AA?0.4.

9. The treatment element according to claim 1, wherein the melting section (32) comprises at least one kneading disk having a tip chamfer.

10. The treatment element according to claim 1, wherein the conveying section has a pitch P.sub.F and an outer diameter D.sub.AF, wherein: 0.75?P.sub.F/D.sub.AF?2.

11. The treatment element according to claim 1, wherein the conveying section has a length L.sub.F and a pitch P.sub.F, wherein: 0.2?L.sub.F/P.sub.F?1.5.

12. The treatment element according to claim 1, wherein the conveying section and the melting section have an offset angle b relative to one another, wherein: 0??b?90?.

13. The treatment element according to claim 1, comprising a supporting section which is arranged downstream of the melting section in the conveying direction and is connected in one piece with the melting section.

14. The treatment element according to claim 13, wherein the supporting section comprises at least one kneading disk.

15. The treatment element according to claim 14, wherein the at least one kneading disk is untwisted.

16. The treatment element according to claim 13, wherein the supporting section comprises at least one kneading disk having a width L.sub.S and an outer diameter D.sub.AS, wherein: 0.05?L.sub.S/D.sub.AS?0.5.

17. The treatment element according to claim 13, wherein the melting section has an outer diameter D.sub.AA and the supporting section has an outer diameter D.sub.AS, wherein D.sub.AA<D.sub.AS.

18. The treatment element according to claim 13, wherein the conveying section has an outer diameter D.sub.AF and the supporting section has an outer diameter D.sub.AS, wherein D.sub.AF<D.sub.AS.

19. A screw machine for treating material, comprising a housing, at least one housing bore formed in the housing, and at least one treatment element shaft which is arranged in the at least one housing bore, wherein the at least one treatment element shaft comprises at least one treatment element according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG. 1 shows a partially sectioned apparatus for treating material using a multi-shaft worm machine,

[0039] FIG. 2 shows a partially sectioned top view onto the apparatus in FIG. 1,

[0040] FIG. 3 shows a sectional illustration of the multi-shaft worm machine along section line III-III in FIG. 2,

[0041] FIG. 4 shows a perspective view of two treatment elements arranged in pairs next to each other according to a first embodiment example, which are part of the multi-shaft worm machine in FIG. 1,

[0042] FIG. 5 shows a first side view of one of the treatment elements in FIG. 4,

[0043] FIG. 6 shows a second side view of the treatment element in FIG. 5,

[0044] FIG. 7 shows a sectional view through the treatment element along section line VII-VII in FIG. 5,

[0045] FIG. 8 shows a perspective view of two treatment elements arranged in pairs next to each other according to a second embodiment example,

[0046] FIG. 9 shows a side view of one of the treatment elements in FIG. 8, and

[0047] FIG. 10 shows a sectional view through the treatment element along section line X-X in FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] A first embodiment example of the invention is described below with reference to FIGS. 1 to 7. An apparatus 1 for treating and preparing material M comprises a multi-shaft worm machine 2, a first dosing installation 3, a second dosing installation 4 and a control installation 5. The material M is in particular a plastic material.

[0049] The multi-shaft worm machine 2 comprises a housing 6 in which two interpenetrating housing bores 7, 8 are formed. The housing bores 7, 8 have the shape of a horizontal figure eight in cross-section. The two interpenetrating housing bores 7, 8 form approximate triangle regions Z. The approximate triangle regions Z are the tapered regions of the housing 6. The approximate triangle regions Z are illustrated in FIG. 3. Treatment element shafts 9, 10 are arranged in the housing bores 7, 8 so as to be rotatable about associated axes of rotation 11, 12. The treatment element shafts 9, 10 can be driven in rotation in the same direction, i.e. in the same directions of rotation, by means of a drive motor 13 via a transfer gear 14. A coupling 15 is arranged between the drive motor 13 and the transfer gear 14.

[0050] A first feed opening 16 and a second feed opening 17 are formed in the housing 6, which open into the housing bores 7, 8. The second feed opening 17 is arranged downstream of the first feed opening 16 in a conveying direction 18. The first dosing installation 3 opens into the first feed opening 16 and serves for feeding the material M. The second dosing installation 4 opens into the second feed opening 17 and serves for feeding at least one additive A. The first dosing installation 3 and/or the second dosing installation 4 is designed, for example, as a gravimetric dosing installation.

[0051] The multi-shaft worm machine 2 comprises, in succession in the conveying direction 18, a first feed zone 19, a melting zone 20, a second feed zone 21, a homogenizing zone 22 and a discharge zone 23. The housing 6 is closed off in the discharge zone 23 by a discharge plate 24 which forms a discharge opening 25.

[0052] The treatment element shafts 9, 10 each comprise a profiled shaft 26, 27, on which screw elements 28, 28, kneading elements 29, 29 and treatment elements 30, 30 according to the invention are arranged in pairs next to each other. In the first feed zone 19, screw elements 28, 28 are arranged on the shafts 26, 27 in a torque-transmitting manner In the melting zone 20, treatment elements 30, 30 and kneading elements 29, 29 according to the invention are arranged on the shafts 26, 27 in a torque-transmitting manner In the second feed zone 21, screw elements 28, 28 are arranged on the shafts 26, 27 in a torque-transmitting manner In the homogenizing zone 22, treatment elements 30, 30 and kneading elements 29, 29 according to the invention are arranged on the shafts 26, 27 in a torque-transmitting manner. In the discharge zone 23, screw elements 28, 28 are arranged on the shafts 26, 27 in a torque-transmitting manner The screw elements 28, 28 and/or the kneading elements 29, 29 are of conventional design. The screw elements 28, 28 and/or the kneading elements 29, 29 and/or the treatment elements 30, 30 according to the invention are in particular of two-flight design. The kneading elements 29, 29 are designed, for example, as individual kneading disks and/or as kneading blocks comprising a plurality of kneading disks that are connected to one another in one piece.

[0053] The treatment elements 30, 30 according to the invention are identical. Only one treatment element 30 is described below.

[0054] The treatment element 30 is used for treating and/or melting material M. The treatment element 30 comprises a conveying section 31, a melting section 32 and a supporting section 33. The melting section 32 is arranged downstream of the conveying section 31 in the conveying direction 18. The conveying section 31 and the melting section 32 are connected to each other in one piece. The supporting section 33 is arranged downstream of the melting section 32 in the conveying direction 18. The melting section 32 and the supporting section 33 are connected to each other in one piece.

[0055] The treatment element 30 has a profiled bore 34 which passes through the conveying section 31, the melting section 32 and the supporting section 33. The profiled bore 34 serves to arrange the treatment element 30 in form-fit manner on the associated profiled shaft 26, so that a torque can be transmitted from the shaft 26 to the treatment element 30.

[0056] The conveying section 31 is designed as a conveying element or screw element. The conveying section 31 comprises a first side S.sub.1F, which is directed upstream in the conveying direction 18, and a second side S.sub.2F, which is directed downstream in the conveying direction 18. The conveying section 31 has a two-flight profile. The conveying section 31 has an outer diameter D.sub.AF and a length L.sub.F in the conveying direction 18. Further, the conveying section 31 defines a helix S.sub.F which has a pitch P.sub.F at one full revolution, i.e. at an angle of 360?. The pitch P.sub.F is also referred to as the lead. For a ratio P.sub.F/D.sub.AF of the pitch P.sub.F to the outer diameter D.sub.AF, the following applies in particular: 0.75?P.sub.F/D.sub.AF?2, in particular 1?P.sub.F/D.sub.AF?1.75, and in particular 1.25?P.sub.F/D.sub.AF?1.5.

[0057] Furthermore, for a ratio L.sub.F/P.sub.F of the length L.sub.F to the pitch P.sub.F, in particular: 0.2 ?L.sub.F/P.sub.F?1.5, in particular 0.3?L.sub.F/P.sub.F?1.2, and in particular 0.4?L.sub.F/P.sub.F?0.9. For the embodiment example in FIG. 5, for example: L.sub.F/P.sub.F=0.5.

[0058] The melting section 32 comprises a number N of kneading disks, wherein the following generally applies: 1?N?7, in particular 2?N?6, and in particular 3?N?5. For the embodiment example according to FIGS. 1 to 7, the following applies by way of example: N=2. The melting section 32 thus comprises a first kneading disk 35 and a second kneading disk 36. A first spacer element 37 is arranged between the first kneading disk 35 and the second kneading disk 36. The spacer element 37 is arranged downstream of the first kneading disk 35 in the conveying direction 18. The second kneading disk 36 is arranged downstream of the spacer element 37 in the conveying direction 18. The first kneading disk 35, the spacer element 37 and the second kneading disk 36 are formed in one piece with each other.

[0059] The first kneading disk 35 has a first side S.sub.1A which is directed upstream in the conveying direction 18. Further, the first kneading disk 35 has a second side S.sub.2A which is directed downstream in the conveying direction 18. Accordingly, the second kneading disk 36 has a first side S.sub.3A which is directed upstream in the conveying direction 18 and a second side S.sub.4A which is directed downstream in the conveying direction 18.

[0060] The second side S.sub.2F of the conveying section 31 is connected in one piece to the first side S.sub.1A of the first kneading disk 35. An offset angle b is defined between the conveying section 31 and the melting section 32, i.e. between the second side S.sub.2F of the conveying section 31 and the first side S.sub.1A of the first kneading disk 35, wherein the following generally applies: 0??b?90?, in particular 5??b?45?, and in particular 10??b?15?. For the embodiment example according to FIGS. 1 to 7, the following applies by way of example: b=0?. The offset angle b is only illustrated in FIG. 6.

[0061] The first kneading disk 35 and the second kneading disk 36 are twisted. The first kneading disk 35 has a twist angle d between the sides S.sub.1A and S.sub.2A. Correspondingly, the second kneading disk 36 has a twist angle d between the sides S.sub.A3 and S.sub.A4. The following generally applies to the twist angle d: 0?<d?30?, in particular 5??d?25?, and in particular 10??d?20?. For the example according to FIGS. 1 to 7, the following applies by way of example: d=15?.

[0062] An offset angle c is formed between the first side S.sub.1A of the first kneading disk 35 and the first side S.sub.3A of the second kneading disk 36. Since the kneading disks 35, 36 have an identical twist angle d, the offset angle c is also formed between the second side S.sub.2A of the first kneading disk 35 and the second side S.sub.4A of the second kneading disk 36. The following generally applies to the offset angle c: 0??c?90?, in particular 15??c?75?, and in particular 30??c?60?. For the embodiment example according to FIGS. 1 to 7, the following applies by way of example: c=45?.

[0063] Furthermore, an offset angle e is formed between the second side S.sub.2A of the first kneading disk 35 and the first side S.sub.3A of the second kneading disk 36. The following applies in particular to the offset angle e: e=c?d. The following applies in general to the offset angle e: 5??e?70?, in particular 10??e?55?, and in particular 15??e?40?. For the embodiment example according to FIGS. 1 to 7, the following applies by way of example: e=30?.

[0064] The kneading disks 35, 36 have an outer diameter D.sub.AA and a width L.sub.A in the conveying direction 18. The outer diameter D.sub.AA of the kneading disks 35, 36 can be identical and/or different. Accordingly, the width L.sub.A of the kneading disks 35, 36 can be identical and/or different. For a ratio L.sub.A/ D.sub.AA of the width L.sub.Ato the outer diameter D.sub.AA, the following applies in particular: 0.1?L.sub.A/ D.sub.AA?0.4, in particular 0.15?L.sub.A/ D.sub.AA?0.35, and in particular 0.2?L.sub.A/ D.sub.AA?0.3.

[0065] The kneading disks 35, 36 define a helix S.sub.A due to the twist or the twist angle d. The helix S.sub.A has a pitch P.sub.A at one full revolution, i.e. at an angle of 360?. The pitch P.sub.A is also referred to as the lead. The pitch P.sub.A is merely indicated in FIG. 5. For a ratio P.sub.A/D.sub.AA, the following applies in particular: 5?P.sub.A/D.sub.AA?10, in particular 6?P.sub.A/D.sub.AA?9, and in particular 7?P.sub.A/D.sub.AA?8.

[0066] The supporting section 33 comprises a kneading disk 38 and a second spacer element 39. The kneading disk 38 is connected in one piece to the second spacer element 39. The kneading disk 38 is arranged downstream of the second spacer element 39 in the conveying direction 18. The kneading disk 38 comprises a first side S.sub.1S which is directed upstream in the conveying direction 18, and a second side S.sub.2S which is directed downstream in the conveying direction 18. The second spacer element 39 is connected in one piece to the second side S.sub.4A of the kneading disk 36 and to the first side S.sub.1S of the kneading disk 38.

[0067] The kneading disk 38 is untwisted or not twisted. This means that a twist angle between the first side S.sub.1S and the second side S.sub.2S is zero. The first side S.sub.1S and the second side S.sub.2S of the kneading disk 38 are thus congruent with each other in the conveying direction 18.

[0068] The kneading disk 38 has an outer diameter D.sub.AS and a width L.sub.S in the conveying direction 18. For a ratio L.sub.S/D.sub.AS of the width L.sub.S to the outer diameter D.sub.AS, the following applies in particular: 0.05?L.sub.S/D.sub.AS?0.5, in particular 0.1?L.sub.S/D.sub.AS?0.35, and in particular 0.15?L.sub.S/D.sub.AS?0.2.

[0069] The spacer elements 37, 39 each have an outer diameter D.sub.AD and a width L.sub.D in the conveying direction 18. The outer diameter D.sub.AD of the spacer elements 37, 39 can be identical and/or different. Further, the width L.sub.D of the spacer elements 37, 39 may be identical and/or different. For a ratio L.sub.D/D.sub.AD of the width L.sub.D to the outer diameter D.sub.AD, the following applies in particular: 0<L.sub.D/D.sub.AD?0.1, and in particular 0.01?L.sub.D/D.sub.AD?0.02.

[0070] The following applies in particular: D.sub.AA<D.sub.AS and/or D.sub.AF<D.sub.AS. Furthermore, D.sub.AD?D.sub.AS and/or D.sub.AD?D.sub.AA and/or D.sub.AD?D.sub.AF applies in particular.

[0071] The housing bores 7, 8 have a diameter D.

[0072] For a ratio D.sub.AF/D applies in particular: 0.8?D.sub.AF/D<1, in particular 0.9?D.sub.AF/D?0.99, and in particular 0.95?D.sub.AF/D?0.98.

[0073] For a ratio D.sub.AA/D, in particular: 0.8?D.sub.AA/D<1, in particular 0.9?D.sub.AA/D?0.99, and in particular 0.95?D.sub.AA/D?0.98.

[0074] For a ratio D.sub.AS/D, in particular: 0.95?D.sub.AS/D<1, in particular 0.98?D.sub.AS/D?0.998, and in particular 0.99?D.sub.AS/D?0.995.

[0075] The functional principle of the apparatus 1 and the treatment elements 30, 30 according to the invention are described below:

[0076] The material M to be processed is fed as bulk material, in particular as powder and/or granules, by means of the first dosing installation 3 through the first feed opening 16 into the multi-shaft worm machine 2. In the first feed zone 19, the material M is conveyed by means of the screw elements 28, 28 in the conveying direction 18 to the melting zone 20.

[0077] In the melting zone 20 the material M is melted by means of the treatment elements 30, 30 according to the invention and the kneading elements 29, 29 arranged downstream in the conveying direction 18. To this end, the treatment elements 30, 30 reduce the load on the shafts 26, 27, on the treatment elements 30, 30 themselves and on the housing 6. Due to the fact that the conveying section 31 and the melting section 32 are formed in one piece with each other, the conveying section 31 and the melting section 32 are not pressed apart even under high loads, so that no gap is formed in front of the first kneading disk 35 and material M or a melt already produced from the material M could penetrate into a resulting gap. In addition, the stiffness of the treatment elements 30, 30 is increased in the critical transition region between the conveying section 31 and the melting section 32, so that deformations and relative movements of the treatment elements 30, 30 and the associated shafts 26, 27 are reduced. The supporting section 33, which is connected in one piece with the melting section 32, additionally reduces relative movements and deformations of the treatment elements 30, 30. The loads on the treatment elements 30, 30, on the shafts 26, 27 and on the housing 6 are reduced in particular in the approximate triangle regions Z. Furthermore, the load on the treatment elements 30, 30 can be adjusted as desired via the offset angles b, c and e as well as the twist angle d, the outer diameters D.sub.AF, D.sub.AA and D.sub.AS as well as the pitch P.sub.F and P.sub.A as well as the length L.sub.F and the widths L.sub.A and L.sub.S.

[0078] In the second feed zone 21, at least one additive A is fed into the multi-shaft worm machine 2 through the second feed opening 17 by means of the second dosing installation 4. The at least one additive A is fed into the melted material M in the second feed zone 21. The melted material M and the at least one additive A are conveyed in the conveying direction 18 to the homogenizing zone 22 by means of the screw elements 28, 28.

[0079] In the homogenizing zone 22, the at least one additive A is melted by means of the treatment elements 30, 30 according to the invention and the kneading elements 29, 29 arranged downstream thereof and mixed into the melted material M. The mixture is homogenized in the homogenizing zone 22. The advantages of the treatment elements 30, 30 according to the invention correspond to the advantages of the treatment elements 30, 30 that are arranged in the melting zone 20.

[0080] In the discharge zone 23, the homogenized mixture is discharged in the usual manner through the discharge opening 25.

[0081] A second embodiment example of the invention is described below with reference to FIGS. 8 to 10. In contrast to the first embodiment example, the kneading disks 35, 36 of the melting section 32 have tip chamfers 40, 41. First tip chamfers 40 are formed as bevels which are arranged on the first side S.sub.1A of the first kneading disk 35 and form a beveled surface between the first side S.sub.1A and a circumferential side U.sub.1A of the first kneading disk 35.

[0082] Second tip chamfers 41 are formed on the circumferential side U.sub.1A of the first kneading disk 35 and on a circumferential side U.sub.2A of the second kneading disk 36. Compared to the first embodiment example, the tip chamfers 41 lead to edge-free circumferential sides U.sub.1A and U.sub.2A. To illustrate a tip chamfer 41, a fictitious edge is drawn on the circumferential side U.sub.2A in FIG. 9, which fictitious edge is actually not present due to the tip chamfer 41.

[0083] Due to the tip chamfers 40, 41, the material volume of the treatment element 30 or 30 is reduced so that the free volume for the material M to be processed is increased in the housing bores 7, 8. This further reduces the load on the treatment elements 30, 30, the shafts 26, 27 and the housing 6. Due to the tip chamfers 41, the kneading disks 35, 36 have an involute profile in the region of the circumferential sides U.sub.1A and U.sub.2A. With regard to the further structure and the functional principle, reference is made to the description of the first embodiment example.