FILTER CANDLE TO SEPARATE CONTAMINANTS FROM A PLASTIC MELT

Abstract

A filter candle to separate contaminants from a plastic melt is disclosed. The filter candle has a filter element through which a melt flow is directed to retain contaminants contained in the melt flow, and a supporting body to support the filter element. The supporting body is a hollow body having multiple passages for the melt flow. At least one additional supporting body is on the side of said filter element that faces away from the supporting body. The additional supporting body acts on surface regions of the filter element and/or accommodates them such that the filter element can be backwashable.

Claims

1. A backwashable candle filter configured to separate contaminants from a plastic melt, the backwashable candle filter comprising: at least one filter element through which a melt flow is directed and which is configured to retain contaminants contained in the melt flow; a supporting body to support the filter element, the supporting body being a hollow body having a wall region with multiple passages for the melt flow; and at least one additional supporting body on a side of said filter element that faces away from the supporting body, the additional supporting body configured to act on surface regions of the filter element or to accommodate the surface regions such that the filter element is backwashable.

2. The backwashable candle filter of claim 1, wherein the supporting body is an internal supporting body, and the additional supporting body is an external supporting body with passages for the melt flow.

3. The backwashable candle filter of claim 2, wherein the external supporting body is a hollow body having passages in its wall, and wherein the internal supporting body and the filter element are arranged in the cavity of the hollow body of the external supporting body.

4. The backwashable candle filter of claim 2, wherein the internal supporting body has a cylindrical external shape and the external supporting body has a cylindrical internal shape, and wherein the filter element is arranged in a gap between the internal and the external supporting body.

5. The backwashable candle filter of claim 2, wherein the internal supporting body and the external supporting body are arranged coaxially.

6. The backwashable candle filter of claim 2, wherein the filter element rests on the internal supporting body and the external supporting body.

7. The backwashable candle filter of claim 2, wherein the internal supporting body and the external supporting body have a polygonal or star external or internal shape.

8. The backwashable candle filter of claim 2, wherein the filter element has a tube body with a pleated circumference.

9. The backwashable candle filter of claim 8, wherein the internal supporting body on its external wall surface facing toward the filter element, or the external supporting body on its internal wall surface facing toward the filter element, has locking elements extending between the folds of the pleated circumference.

10. The backwashable candle filter of claim 8, wherein the internal supporting body and the external supporting body have pleated circumferences, and wherein the filter element is arranged in a corrugated gap between the internal and external supporting bodies.

11. The backwashable candle filter of claim 2, wherein the internal and external supporting bodies are coupled with one another via a releasable connection, and the filter element is designed to be exchangeable.

12. The backwashable candle filter of claim 2, wherein the internal supporting body or the external supporting body has an abutment part for the other supporting body.

13. The backwashable candle filter of claim 12, further comprising a clamping ring and an attachment part, said attachment part interacting with said clamping ring, such that when the attachment part is accommodated on one of the internal and external supporting bodies in a screwable manner, the internal and external supporting bodies are fixed to one another.

14. The backwashable candle filter of claim 13, wherein the attachment part has a conical segment that projects into internal space of the internal supporting body, and wherein the conical segment extends across part of the length of the internal supporting body.

15. The backwashable candle filter of claim 13, wherein the attachment part is a tie rod that extends through internal space of the internal supporting body from one end of the backwashable candle to the other end.

16. A plastic-processing device, comprising: a housing defining a flow path for a plastic melt flowing within the housing; and the backwashable candle filter of claim 1 arranged in the flow path.

17. A method of using the backwashable candle filter of claim 1 to separate contaminants from a plastic melt in a plastic-processing device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In the following, the invention is described in greater detail with reference to attached figures using various exemplary embodiments. Shown are:

[0033] FIG. 1: a perspective view of a first exemplary embodiment of a filter candle according to the invention, in an exploded view;

[0034] FIG. 2: a view of the filter candle according to FIG. 1, in longitudinal section;

[0035] FIG. 3: a view of another embodiment of the filter candle according to the invention, in cross section;

[0036] FIG. 4: a perspective view of a third exemplary embodiment of a filter candle according to the invention;

[0037] FIG. 5: a view of the filter candle according to FIG. 4, in longitudinal section;

[0038] FIG. 6: a perspective view of a fourth exemplary embodiment of a filter candle according to the invention, in an exploded view, and

[0039] FIG. 7: a view of the filter candle according to FIG. 6, in cross section.

DETAILED DESCRIPTION

[0040] FIG. 1 shows a filter candle 1 that has an internal supporting body 2 and an external supporting body 4 for a filter element 6 arranged between the internal and external supporting body 2, 4. The internal supporting body 2 and the external supporting body 4 are preferably designed as hollow cylinders 8, 8 which have a plurality of passages 10, 10 in their walls. The filter element 6 has a filter medium 12 covering the passages 10, 10 on the internal and external supporting body 2, 4, which filter medium 12 is arranged in the form of a filter tube between the external wall surface 14 of the internal supporting body 2 and the internal wall surface 16 of the external supporting body 4. The filter element 6 has an internal shell surface 18 and an external shell surface 18 which rest on the wall surfaces 14, 16 of the supporting bodies 2, 4.

[0041] Arranged on the internal supporting body 2 is a flange-like stop part 20 for the filter element 6 and the external supporting body 4, with which stop part 20 at least the alignment of the filter element 6 in the longitudinal direction and of the external supporting body 4 relative to the internal supporting body 2 takes place. The stop part 20 is arranged at the end of the internal supporting body 2 that has an outlet 21 for the melt flow during the regular filtration process. Arranged at the opposite end of the internal supporting body 2 is a clamping ring 22 and an attachment part 24 interacting with the clamping ring 22, which attachment part 24 is screwed together with the opposite end of the internal supporting body 2. The filter element 6 and the external supporting body 4 are fixed between the abutment part 20 and the clamping ring 22. An alignment of the supporting bodies 2, 4 and the filter element 6 in the radial direction relative to one another likewise takes place with the abutment part 20 and the clamping ring 22.

[0042] FIG. 2 shows the filter candle 1 from FIG. 1 in longitudinal section. As FIG. 2 illustrates, the internal supporting body 2, the external supporting body 4 and the filter element arranged between the supporting bodies 2, 4 are arranged coaxially. The passages 10, 10 in the supporting bodies 2, 4 are respectively completely covered by the filter medium 12 of the filter element 6. The attachment part 24 has a conical segment 26 that seals the end of the internal supporting body 2 that is situated opposite the outlet 21 for the plastic melt and protrudes into the free, internal cavity 28 of the internal supporting body 2. The conical segment 26 ensures that no or minimal no-flow zones arise in the cavity 28 and that the melt is thus supplied to the outlet 21 in a targeted manner.

[0043] During the filtration process of the plastic melt, said plastic melt flows with an essentially radially directed flow direction 30 from the outside through the passages 10 in the external supporting body 4 through the filter element 6 and through the passages 10 of the internal supporting body 2 into the free cavity 28. From there, the plastic melt flows with an essentially axially directed flow direction 32 from the free cavity 28 via the outlet 21 on the internal supporting body 2 out of the filter candle 1. During the backwash process, the plastic melt flows in directions opposite the flow directions 32, 30 in order to clean the filter element 6.

[0044] Shown in FIG. 3 is an additional exemplary embodiment of a filter candle 1 which has a filter element 6 arranged between the external wall surface 14 of the internal supporting body 2 and the internal wall surface 16 of the external supporting body 4, which filter element 6 is pleated in the circumferential direction. The filter element 6 has pleats in the circumferential direction, whereby its filter area is increased in comparison to the filter element 6 shown in FIG. 2.

[0045] FIGS. 4 and 5 show a third embodiment of a filter candle 1 which has an internal supporting body 2, [sic] an external supporting body 4. The filter element 6 designed as a tube body is arranged between the external wall surface 14 of the internal supporting body 2 and the internal wall surface 16 of the external supporting body 4, which are designed as hollow cylinders 8, 8. The filter candle 1 furthermore comprises an abutment part 20 that is designed separate from the internal supporting body 2. The abutment part 20 can be arranged and attached at the end of the internal supporting body 2 having the outlet 21 for the plastic melt. Via the abutment part 20, the filter element 6 and the external supporting body 4 in the embodiment shown here are also aligned and fixed in the axial and radial direction and sealed at the ends. At the end opposite the outlet 21, a clamping ring 22 is again provided that, in the shown embodiment, fixes the filter element 6 and the external supporting body 4 via an attachment part 24 having a tie rod 33. Similar to the attachment part 24 from FIG. 2, the tie rod 33 which extends up to the end having the outlet 21 has a conical segment 26.

[0046] As FIG. 5 furthermore shows, a screw-in bushing 34 for a threaded pin 36 arranged at the end of the tie rod 33 is also provided in the region of the outlet 21. A plurality of passage channels 38 via which the plastic melt can flow out of the cavity 28 inside the supporting body 2 are formed between an attachment segment 37 bordering the outlet 21 and the screw-in bushing 34.

[0047] A fourth exemplary embodiment of a filter candle 1 according to the invention is depicted in FIGS. 6 and 7. The filter candle 1 has an internal supporting body 2, an external supporting body 4, and a filter element 6, wherein the supporting body 2, 4 and the filter element 6 are designed as hollow bodies and have body walls 40, 40, 42 that are pleated, i.e. folded, in the circumferential direction. In the shown embodiment, the supporting bodies 2, 4 and the filter element 6 have a star shape in cross section. An increased filter area for the plastic melt to be freed of contaminants is produced by the folded embodiment.

[0048] The external supporting body 2 and the filter element 6 are again aligned via the abutment part 20 arranged or attachable in the internal supporting body 2 and via the clamping ring 22 as well as the attachment part 24 in the axial and radial direction relative to the internal supporting body 2, and/or are attached or arrested on the latter. The attachment part 24 has a conical segment 26 that projects in segments into the cavity 28 of the internal supporting body 2. Identical components are designated with the same reference numbers.

REFERENCE SYMBOL LIST

[0049] 1, 1, 1, 1 Filter candle [0050] 2, 2, 2 Internal supporting body [0051] 4, 4, 4 External supporting body [0052] 6, 6, 6 Filter element [0053] 8, 8 Hollow cylinder [0054] 10, 10 Passage [0055] 12 Filter medium [0056] 14, 14 External wall surface [0057] 16, 16 Internal wall surface [0058] 18, 18 Shell surface [0059] 20, 20 Abutment part [0060] 21, 21 Outlet [0061] 22 Clamping ring [0062] 24, 24 Attachment part [0063] 26, 26 Conical segment [0064] 28, 28 Cavity [0065] 30, 32 Flow direction [0066] 33 Tie rod [0067] 34 Screw-in bushing [0068] 36 Threaded pin [0069] 37 Attachment segment [0070] 38 Passage channel [0071] 40, 40 Body wall [0072] 42 Body wall