OVERTURNING DEVICE FOR OVERTURNING MOLTEN MATERIAL IN A MELT CHANNEL AND PURGING METHOD

Abstract

The present invention relates to an overturning device (10) for overturning a molten material (200) in a melt channel (110) comprising a melt inlet (20) and a melt outlet (30), wherein between the melt inlet (20) and the melt outlet (30) at least a melt guiding means (40) is assembled for a rearrangement of the molten material (200) from the centre (22) of the melt inlet (20) to the edge (34) of the melt outlet (30) and for a rearrangement of the molten material (200) from the edge (24) of the melt inlet (20) into the centre (32) of the melt outlet (30).

Claims

1. An overturning device for overturning a molten material in a melt channel comprising a melt inlet and a melt outlet, wherein between the melt inlet and the melt outlet at least a melt guiding means is assembled for a rearrangement of the molten material from the centre of the melt inlet to the edge of the melt outlet and for a rearrangement of the molten material from the edge of the melt inlet into the centre of the melt outlet, wherein the at least one melt guiding means comprises a separation section with a first separation channel and a second separation channel, wherein in front of the separation section a divisional section for dividing the molten material to the separation channels and after the separation section a combination section from merging the molten material from the separation channels is assembled, wherein the combination section is configured for a central merging of the edge sections of the molten material, wherein a recombination of separation streams of the molten material occurs by a complete or mainly complete rearrangement.

2. The overturning device according to claim 1, wherein the at least one melt guiding means comprises a first guidance channel with a guidance opening in the centre of the melt inlet and at least one guidance outlet at the edge of the melt outlet.

3. The overturning device according to claim 2, wherein the at least one melt guidance means comprises a second guidance channel with a guidance outlet in the centre of the melt outlet and at least a guidance opening at the edge of the melt inlet.

4-5. (canceled)

6. The overturning device according to claim 1, wherein a shifting device is provided for a shifting of the overturning device between the first position in which the melt inlet and the melt outlet are assembled in a fluid communicating connection with the melt channel and a second position in which the melt inlet and the melt outlet are separated from the melt channel.

7. The overturning device according to claim 1, wherein the melt inlet and the melt outlet comprise a free flow area, which corresponds to or mainly corresponds to the free flow area of the melt channel.

8. The overturning device according to claim 7, wherein the free flow area of the melt guidance means corresponds or mainly corresponds at least to the free flow area of the melt inlet or to the free flow area of the melt outlet.

9. A blow head for performing a blow head extrusion method comprising at least a melt channel for the conveyance of molten material to a blow outlet of the blow head, wherein in the at least one melt channel at least one overturning device for overturning a molten material in a melt channel comprising a melt inlet and a melt outlet is assembled, wherein between the melt inlet and the melt outlet at least a melt guiding means is assembled for a rearrangement of the molten material from the centre of the melt inlet to the edge of the melt outlet and for a rearrangement of the molten material from the edge of the melt inlet into the centre of the melt outlet, wherein the at least one melt guiding means comprises a separation section with a first separation channel and a second separation channel, wherein in front of the separation section a divisional section for dividing the molten material to the separation channels and after the separation section a combination section from merging the molten material from the separation channels is assembled, wherein the combination section is configured for a central merging of the edge sections of the molten material, wherein a recombination of separation streams of the molten material occurs by a complete or mainly complete rearrangement.

10. The blow head according to claim 9, wherein the overturning device with regard to the length of the melt channel is assembled in the centre or mainly in the centre of the melt channel.

11. A method for performing a purge process in an extrusion device, comprising the following steps: Insertion of the molten material into a melt inlet of an overturning device for overturning a molten material in a melt channel comprising a melt inlet and a melt outlet, wherein between the melt inlet and the melt outlet at least a melt guiding means is assembled for a rearrangement of the molten materials from the centre of the melt inlet to the edge of the melt outlet and for a rearrangement of the molten material from the edge of the melt inlet into the centre of the melt outlet, wherein the at least one melt guiding means comprises a separation section with a first separation channel and a second separation channel, wherein in front of the separation section a divisional section for dividing the molten material to the separation channels and after the separation section a combination section from merging the molten material from the separation channels is assembled, wherein the combination section is configured for a central merging of the edge sections of the molten material, Rearrangement of molten material from the centre of the melt inlet to the edge of the melt outlet of the overturning device and Rearrangement of molten material from the edge of the melt inlet into the centre of the melt outlet, wherein a recombination of separation streams of the molten material occurs by a complete or mainly complete rearrangement.

Description

[0032] Further advantages, features and details of the invention result from the subsequent description in which in relation to the drawings embodiments of the invention are described in detail. Thereby, the features described in the claims and in the description can be essential for the invention each single for themselves or in any combination. It is shown schematically:

[0033] FIG. 1 a schematic representation during a purge process of known extrusion devices,

[0034] FIG. 2 a situation according to FIG. 1 with the use of an overturning device according to the invention,

[0035] FIG. 3 an embodiment of an overturning device according to the invention,

[0036] FIG. 4 the embodiment of FIG. 3 with a further representation of flow conditions of the molten material,

[0037] FIG. 5 a further embodiment of the overturning device according to the invention,

[0038] FIG. 6 a schematic representation of the effect of an overturning device,

[0039] FIG. 7 a further embodiment of an overturning device according to the invention,

[0040] FIG. 8 a further embodiment of the overturning device according to the invention,

[0041] FIG. 9 an embodiment of a blow head according to the invention, and

[0042] FIG. 10 a further embodiment of a blow head according to the invention.

[0043] In FIG. 1 a melt channel 110 with the flow direction from left to the right is shown like it is represented during the purge process. Within, the melt channel 110 a free flow area 70 is provided through which molten material 200 is flowing. Here, it has to be distinguished between old molten material 220 and new molten material 210. It can be recognized that via the longitudinal course of the melt channel 110 during the purge process a ramp-like or cone-like configuration between the old molten material 220 and the new molten material 210 is configured. This cone moves during the course of the purge time to the right until finally the greatest part of the old molten material 220 is pushed out and now it can be continued with an active production.

[0044] In FIG. 2 the mode of action of an overturning device 10 according to the invention is shown. Here now a rearrangement from the edge of the molten material 200 into the centre of the molten material 200 and vice versa occurs. At the melt inlet 20 of the overturning device 10 accordingly material is received from the edge of the molten material 200 and is provided in the centre at the melt outlet 30. In an inverse manner fresh or new molten material 210 is guided from the centre of the melt inlet 20 to the edge of the melt outlet 30. Like it can be recognized, therewith the adapted amount of old molten material 220 at the right end of the melt channel 110 is reduced. The representation of FIG. 2 occurs at the same time during the purge process like FIG. 1.

[0045] FIGS. 3 and 4 show a first embodiment of the overturning device 10 according to the invention. This overturning device 10 is configured with two guidance channels 42 and 44 as melt guidance means 40. Via a not further described ring collector a guidance opening 44a at the edge 24 of the melt inlet 20 is provided such that the corresponding molten material 200 can flow into the guidance channel 44. This is shown with arrows in FIG. 4. Via a guidance outlet 44b in the centre 32 of the melt outlet 30 now the rearrangement from the edge into the centre for this material of the molten material 200 occurs.

[0046] In the same manner in the centre 22 of the melt inlet 20 a guidance opening 42a of the first guidance channel 42 is provided, which renders it possible to rearrange the molten material 200 at the edge 34 of the melt outlet 30 and the corresponding guidance outlet 42b along the arrows of FIG. 3. This is a technical solution using an active rearrangement, wherein the overturning device 10 is part of the melt channel 110.

[0047] FIG. 5 shows a reduced complexity concerning the embodiment of FIG. 3 and FIG. 4. Here only a closed second guidance channel 40 with corresponding guidance openings 44a and guidance outlet 44b is provided. The remaining material of the molten material 200 is either not contacted at the upper edge guided through the melt guidance means 40 or guided at the lower edge starting from the melt inlet 20. The corresponding sections A-A and B-B are shown in the lower area of FIG. 5, wherein likewise the arrows show the corresponding rearrangement movements.

[0048] FIGS. 6 and 7 show the possibility to provide a rearrangement by a separation functionality. Starting from a melt channel 110 according to FIG. 7 via a divisional section 47 a division of the molten material 200 to two separation channels 46a and 46b of the separation section 46 occurs. This leads schematically to a distribution according to FIG. 6. While starting from the melt channel 110 old molten material 220 completely encloses the new molten material 210, by a separation in the separation channels 46a and 46b only approximately half of the extent with old molten material 220 is covered. The other half of the separation channels 46a and 46b is at the edge equipped with already new molten material 210. If now by clever combining the central merging of two separation channels 46 for the edge sections with the old molten material 220 is performed, likewise a complete or at least partial rearrangement according to the invention can occur by this separation function.

[0049] FIG. 8 schematically shows a further possible embodiment of an overturning device 10 with this separation functionality. Here, a separation in total four separation channels 46a and 46b and a recombining in a combination section 48 occur. Further, the corresponding distribution of old molten material 220 and new molten material 210 in the corresponding channels is schematically shown. After a combination or merging at the combination section 48 the edge sections with old material 220 are assembled in the centre such that the extent edge in the melt channel 110 is configured mainly completely by the new molten material 210.

[0050] FIG. 9 shows how in a melt channel 110 in a blow head 100 an overturning device 10 can be assembled. Thereby, each of the described embodiments of the overturning device 10 can be involved.

[0051] FIG. 10 shows a solution similar to FIG. 9, wherein however here a shifting device 60 for the overturning device 10 is shown. According to FIG. 10 the overturning device 10 is in the second position and therewith not in fluid communicating connection with the melt channel 110. This is the operation position. For the purge situation the overturning device 10 is introduced in the melt channel 110 via the shifting device 60 and therewith the functionality according to the invention for the reduction of the purge time can be provided.

[0052] The previous description of the embodiments describes the present invention only within the scope of examples. Naturally, single features of the embodiments as far as technically meaningful can be freely combined with one another without leaving the scope of the present invention.

REFERENCE LIST

[0053] 10 Overturning device

[0054] 20 Melt inlet

[0055] 22 Centre of melt inlet

[0056] 24 Edge of melt inlet

[0057] 30 Melt outlet

[0058] 32 Centre of melt outlet

[0059] 34 Edge of melt outlet

[0060] 40 Melt guiding means

[0061] 42 First guidance channel

[0062] 42a Guidance opening

[0063] 42b Guidance outlet

[0064] 44 Second guidance channel

[0065] 44a

[0066] Guidance opening

[0067] 44b Guidance outlet

[0068] 46 Separation section

[0069] 46a First separation channel

[0070] 46b Second separation channel

[0071] 47 Divisional section

[0072] 48 Combination section

[0073] 60 Shifting device

[0074] 70 Free flow area

[0075] 100 Blow head

[0076] 110 Melt channel

[0077] 120 Blow output

[0078] 200 Molten material

[0079] 210 New molten material

[0080] 220 Old molten material