MELT DISTRIBUTOR

Abstract

A melt distributor (1) having a plurality of bifurcated melt passages melt passages (5.1, 5.2, 5.3) for redirecting and distributing melt flows from a thermoplastic plastic. The melt distributor can be connected to a multiple extrusion head for producing multi-layer preforms. The branched junction (8) is configured as a rounded y-shaped conduit branch, and at least the branched junction (8) between a supply passage part (6) and the discharging passage parts (7.1, 7.2) of the bifurcated melt passage follows a continuously bent curve, the curvature of which is not equal to zero. The rounded and continuously bent configuration of the branched junction (8) contributes to shorter flow paths and avoids the formation of dead zones.

Claims

1. A melt distributor for deflecting and distributing melt from a thermoplastic plastic, wherein the melt distributor can be connected to a multilayer extrusion head for the manufacture of multilayer preforms from the melt of the plurality of melt flows, the melt distributor comprising: one or more bifurcated melt passages, each of the one or more bifurcated melt passages comprising: a feeding passage part at least two discharging passage parts; and a branched junction provided between the feeding passage part and the at least two discharging passage parts, wherein the feeding passage part has an inlet for the melt at an end thereof, and each of the at least two discharging passage parts has an outlet for the melt at an end thereof, wherein at least the branched junction is configured as a rounded Y-shaped line branch, and wherein the branched junction is arranged between the feeding passage part and the two connected discharging passage parts follows a continuously bent curve, a curvature of which is not equal to zero; and wherein the melt distributor comprises a one-piece component and each of the one or more bifurcated melt passages are arranged in the one-piece component, and wherein the one piece component provided with the one or more bifurcated melt passages is manufactured with a mold-less, additive manufacturing process for metallic material.

2. A melt distributor for deflecting and distributing a melt of a thermoplastic plastic, wherein the melt distributor is connected to a multilayer extrusion head for the manufacture of multilayer preforms from the melt of the plurality of melt flows, the melt distributor comprising: a plurality of bifurcated melt passages, each of the plurality of bifurcated melt passage comprising: a feeding passage part; at least two discharge passage parts; and a branched junction between the feeding passage part and the discharging passage parts, wherein the feeding passage part has an inlet for the melt at an end thereof and each discharging passage part has an outlet for the melt at an end thereof, wherein at least the branched junction is a rounded Y-shaped line junction and wherein the branched junction between the feeding passage part and the two connected discharge passage parts follows a continuously bent curve, which is not equal to zero, wherein the melt distributor is configured with two or more ring segments which are arranged radially adjacent to each other, wherein each of the plurality bifurcated melt passages is arranged in one of the ring segments and the melt distributor is configured as a one-piece component; or a subset of the plurality of bifurcated melt passages is arranged in one of the ring segments and the melt distributor is configured as a one-piece component, and wherein in the one-piece component with the bifurcated melt passage or with the bifurcated melt passages is manufactured with a mold-less, additive manufacturing process for metallic materials.

3. A melt distributor according to claim 1, wherein arc lengths of the bent curves in the branched junction have a center angle of less than 90°.

4. A melt distributor according to claim 1, wherein at the branched junction of a bifurcated melt passage a upstream section of the feeding passage part and/or wherein each branched junction is followed by a downstream section of the discharge passage parts, and wherein the upstream section or the downstream sections also follow a continuously bent curve, the curvature of which is not equal to zero.

5. A melt distributor according to claim 1, wherein a plurality of inlets of the plurality of bifurcated melt passages are located on a straight line at an inlet side of the melt distributor and/or wherein a plurality of outlets or all of the outlets of the bifurcated melt passages are located on a straight line at the outlet side of the melt distributor.

6. A melt distributor according to claim 1, wherein all inlets are arranged on an inlet side of the melt distributor are and/or all outlets are arranged on an opposite outlet side of the melt distributor.

7. A melt distributor according to claim 1, wherein the one or more bifurcated melt passages has downstream located diameters, comprising an end diameter or exit diameter of the discharging passage parts and/or of the outlet, and has an upstream located diameter, comprising an inlet diameter of the feeding passage part and/or the inlet, wherein a ratio of the downstream located diameter to the upstream located diameters is selected such that a flow velocity of the incoming plastic melt is essentially equal to a flow velocity of the plastic melt being released; and/or wherein along the melt flow, the sum of the passage diameters located downstream is essentially equal to the passage diameters located upstream.

8. A melt distributor according to claim 1, wherein the one or more bifurcated melt passages along a melt flow direction have a uniform overall passage diameter, so that within the one or more bifurcated melt passages a uniform flow velocity exists.

9. A melt distributor in accordance with claim 1, wherein the curvature in each length area of the one or more bifurcated melt passages is selected such that a ratio of the local radius of curvature to a local diameter of the one or more bifurcated melt passages is greater than or equal to a minimum ratio limit value, wherein the minimum ratio value is greater than.

10. An assembly unit comprising an extrusion head, and a melt distributor according to claim 1.

11. A mulitple extrusion head for a simultaneous manufacture of a plurality of multilayer preforms, the multiple extrusion head comprising a plurality of assembly units in accordance with claim 10, in which a plurality of adjacent groups of bifurcated melt passages are provided.

12. A melt distributor according to claim 2, wherein arc lengths of the bent curves in the branched junction have a center angle of less than 90°.

13. A melt distributor according to claim 2, wherein at the branched junction of a bifurcated melt passage a upstream section of the feeding passage part and/or wherein each branched junction is followed by a downstream section of the discharge passage parts, and wherein the upstream section or the downstream sections also follow a continuously bent curve, the curvature of which is not equal to zero.

14. A melt distributor according to claim 2, wherein a plurality of inlets of the plurality of bifurcated melt passages are located on a straight line at an inlet side of the melt distributor and/or wherein a plurality of outlets or all of the outlets of the bifurcated melt passages are located on a straight line at the outlet side of the melt distributor.

15. A melt distributor according to claim 2, wherein all inlets are arranged on an inlet side of the melt distributor are and/or all outlets are arranged on an opposite outlet side of the melt distributor.

16. A melt distributor according to claim 2, wherein the one or more bifurcated melt passages has downstream located diameters, comprising an end diameter or exit diameter of the discharging passage parts and/or of the outlet, and has an upstream located diameter, comprising an inlet diameter of the feeding passage part and/or the inlet, wherein a ratio of the downstream located diameter to the upstream located diameters is selected such that a flow velocity of the incoming plastic melt is essentially equal to a flow velocity of the plastic melt being released; and/or wherein along the melt flow, the sum of the passage diameters located downstream is essentially equal to the passage diameters located upstream.

17. A melt distributor according to claim 2, wherein the one or more bifurcated melt passages along a melt flow direction have a uniform overall passage diameter, so that within the one or more bifurcated melt passages a uniform flow velocity exists.

18. A melt distributor in accordance with claim 2, wherein the curvature in each length area of the one or more bifurcated melt passages is selected such that a ratio of the local radius of curvature to a local diameter of the one or more bifurcated melt passages is greater than or equal to a minimum ratio limit value, wherein the minimum ratio value is greater than.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In the drawings:

[0037] FIG. 1 is a melt distributor according to the in-house state of the art;

[0038] FIG. 2A is a partially transparent view of a melt distributor according to the present disclosure in a front view and a side view from the left-hand side;

[0039] FIG. 2B is a partially transparent perspective view of the melt distributor according to FIG. 2A; and

[0040] FIG. 3 is a multiple extrusion head, which is connected to a plurality of extruders for providing different melt flows.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0041] Referring to the drawings, A preferred embodiment of the melt distributor 1 according to the present disclosure is shown in related views in FIGS. 2A and 2B.

[0042] The melt distributor 1 comprises in the example a one-piece, metallic component 2 with an inlet side 3 and with an outlet side 4. The inlet side 3 is the upper side in the example and the outlet side 4 is the opposing lower side. This constellation is assumed below for simplification of the view. As an alternative, the inlet side 3 and the outlet side 4 may have a different orientation in relation to one another or in space.

[0043] Three bifurcated melt passages 5.1, 5.2, 5.3 extend between the inlet side 3 and the outlet side 4 in the example shown. The number of the melt passages may deviate from this example. One, two, three, four or even more melt passages may be provided. These melt passages may preferably be located in space zones adjacent to one another, so that the melt passages do not touch each other. One or more space zones may have a segment shape, which extends especially along a principal axis X as a linear body. A space zone may thus especially preferably have the shape of a cylinder ring. The principal axis X may be located in an axial center of the melt distributor. Another and preferably linear passage (not shown) may be provided there, which may be used, for example, for the passing through of a media connection or of a mechanical component.

[0044] In the simplest case, the melt distributor 1 comprises precisely one bifurcated melt passage with the branched junction 8 according to the present disclosure with the continuous curvature. In addition, other melt passages with different courses may be provided. As an alternative, two, three or all melt passages may, in turn, have a bifurcated course and a branched junction 8 according to the present disclosure.

[0045] The component 2 is configured, for example, as a one-piece, metallic block, in which the one or more bifurcated melt passages 5.1, 5.2, 5.3 are arranged as fluid-conveying passages. The block with the fluid-conveying passages forming the melt passages 5.1, 5.2, 5.3 is manufactured by way of an additive manufacturing process, especially by way of selective laser melting (Selective Laser Melting, abbreviated as SLM).

[0046] At least one and preferably each bifurcated melt passage 5.1, 5.2, 5.3 has a feeding passage part 6 for the melt as well as at least two discharging passage parts 7.1, 7.2 and precisely two discharging passage parts 7.1, 7.2 according to the preferred embodiment. The bifurcated melt passage 5.1, 5.2, 5.3 according to the present disclosure has a branched junction 8, which is highlighted by a box in FIG. 2A, between the feeding passage part 6 and the two discharging passage parts 7.1, 7.2. The branched junction 8 is configured as a rounded y-shaped line branch. The line branch may further preferably be configured as symmetrical, especially symmetrical to a central plane.

[0047] The feeding passage part 6 has an inlet 9 at the end. The inlets of a plurality of bifurcated melt passages may according to a preferred embodiment be located on the inlet side 3 of the component 2. Each discharging pipeline part 7.1, 7.2 has an outlet 10 at the end. All outlets 10 are preferably arranged on the outlet side 4. Adjoining the inlet 9 or the outlet 10, the individual passage parts or each passage part 6, 7.1, 7.2 may have a upstreeam section 18 or a downstream section 19 with a different geometry. A upstream section 18 or a downstream section 19 may have, in particular, a short, linear, cylindrical passage section 11. This may extend, for example, at right angles to the inlet side 3 or to the outlet side 4 of the component 2.

[0048] The branched junction between the feeding passage part 6 and the discharging passage parts 7.1, 7.2 of the bifurcated melt passage 5.1, 5.2, 5.3 and possibly the downstream sections of the discharging passage parts 7.1, 7.2, which sections adjoin the branched junction 8, follow, however, a bent curve, the curvature of which is continuous and is not equal to zero. This continuously bent course according to the present disclosure of the bifurcated melt passage has no deflections and no dead zones. A continuous curvature may also be called a steady curvature or as a course with a steadily changing value of the curvature.

[0049] The arc lengths of the bent curves in the branched junction 8 have according to an especially preferred embodiment a center angle W of less than 90°. This configuration may be intended for one, a plurality of or all bifurcated melt passages of the melt distributor 1.

[0050] FIG. 3 shows an example for the interaction of the melt distributor 1 according to the present disclosure with one or more extruders and with an extrusion head. The inlets 9 of the melt distributor shown in FIGS. 2A and 2B can be connected or are connected in the example shown (directly) to the outlets of three extruders 14.1, 14.2, 14.3, shown only in FIG. 3. One extruder is a melt conveyor, which provides and conveys the melt flow from a thermoplastic plastic. In alternative embodiments, only one, two, four or any desired other number of extruders may be provided. Further, at least one melt flow may be provided from a different source.

[0051] The inlet 9 of the bifurcated melt passage 5.1 is connected to the extruder 14.1 for the formation of the principal layer of a preform from thermoplastic plastic. This bifurcated melt passage 5.1 has the largest inlet diameter. Thermoplastic plastic materials are fed via the two other bifurcated melt passages 5.2, 5.3 for the formation of other layers of the multilayer preform, which layers are combined in a tube-forming unit of a multilayer extrusion head 15.

[0052] The diameter located downstream, i.e., the outlet diameter at the outlets 10 and/or the passage diameter of the discharging passage parts 7.1, 7.2, are preferably smaller than the diameter located upstream, i.e., the inlet diameter of the feeding passage part 6. The ratio of the diameter located downstream to the diameters located upstream is preferably selected to be such that the flow velocity of the entering plastic melt is essentially equal to the flow velocity of the plastic melt being released. Furthermore, the sum of the passage diameters located downstream is preferably essentially equal to the passage diameters located upstream along the melt flow. As a result, the formation of dwell zones in the run of the melt flow is prevented. Dwell zones are often formed in passage areas, in which a local increase in the (cross-sectional) diameter occurs, which leads to a local reduction in the flow velocity. This reduced flow velocity may lead to the formation of deposits in the edge area of the passage, which may generate the same adverse effect, such as the dead zones mentioned above.

[0053] A bifurcated melt passage (5.1, 5.2, 5.3) has especially preferably a uniform overall passage diameter along the melt flow, so that the flow velocity (average in relation to the cross section) of the melt is essentially identical along the passage, especially preferably regardless of whether the melt is located in the feeding passage part (6) or (as a split melt flow) in the discharging passage parts (7.1, 7.2). In other words, the overall diameter of the passage parts is thus selected to be such that a uniform flow velocity is present within the bifurcated melt passage (5.1, 5.2, 5.3).

[0054] The overall passage diameter is identical to the local diameter of the feeding passage part (6) in a length section of the feeding passage part (6). In a length section of the (related and adjacent to one another) discharging passage parts (7.1, 7.2), the overall diameter is formed by the sum of the individual diameters of these discharging passage parts (7.1, 7.2), which are present at the length sections, which correspond to one another in the flow direction.

[0055] According to another aspect of the present disclosure, the curvature is preferably selected in each length area of the bifurcated melt passage (5.1, 5.2, 5.3) to be such that the ratio of the local radius of curvature to the local diameter of the passage is greater than or equal to a minimum ratio limit value. The minimum ratio limit value may be set as a function of the material of the plastic melt to be processed and of the pressure. It is especially at least 2.5. The minimum ratio limit value has especially preferably the value 3.

[0056] The above views assume that the passage parts (6, 7.1, 7.2) have an essentially circular or oval cross section, so that the diameter correlates directly with the cross-sectional area of the passage. Such a view is common in rheology and the essentially circular or oval cross-sectional shape is the preferred configuration. A person skilled in the art recognizes that a different geometric variable is also covered by the term “diameter,” which variable is suitable for describing the width of the respective passage and has a corresponding action for the conduction of the melt flow, taking the fluid-dynamic laws into consideration, especially with respect to the influence of the local flow velocity and with respect to the formation of dead zones and dwell zones.

[0057] All inlets 9 of the three bifurcated melt passages 5.1, 5.2, 5.3 extend in the example from FIG. 3 on a straight line 12 on the inlet side 3 of the melt distributor. And all outlets 10 of the bifurcated melt passages 5.1, 5.2, 5.3 extend on a straight line 13 on the outlet side 4 of the melt distributor 1. The lines 12, 13 extend in this case in the viewing direction of the principal axis X at right angles to one another, so that the passage parts 6, 7.1, 7.2 follow a branching, bent space curve between the inlet 9 and the two outlets 10. The two discharging passage parts 7.1, 7.2 have a matching shape, so that the melt flow distributed in the bifurcated melt passage 5.1, 5.2, 5.3 enters in the multilayer extrusion head 15 adjoining the melt distributor 1 under corresponding conditions. This matching symmetrical shape and length of the discharging passage parts may preferably be provided in a plurality of or in all melt passages.

[0058] A melt distributor 1 and a multilayer extrusion head 15 may each form an assembly unit 16.

[0059] As shown in FIG. 3, a plurality of assembly units 16 are preferably combined to form a multiple extrusion head 17 in order to extrude a plurality of preforms simultaneously, which preforms are each preferably built up from a plurality of melt layers.

[0060] It is, furthermore, possible to provide two, three or more adjacent groups of melt passages with the configuration according to the present disclosure in a melt distributor, wherein an extrusion head is arranged downstream of each group of melt passages.

[0061] Different variations of the present invention are possible. Especially the features shown, described or claimed in relation to the respective exemplary embodiments may be combined with each other in any desired manner or be replaced with each other.

[0062] A melt passage is according to the present disclosure a line passage for deflecting and possibly for distributing a melt from a thermoplastic plastic. The melt passage may be configured as a pipeline. A passage part may be correspondingly configured as a pipeline part.

[0063] While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

LIST OF REFERENCE NUMBERS

[0064] Present invention (FIGS. 2 and 3)

1 Melt distributor

2 Component

[0065] 3 Upper side/inlet side
4 Lower side/outlet side
5.1 Bifurcated melt passage/bifurcated pipeline
5.2 Bifurcated melt passage/bifurcated pipeline
5.3 Bifurcated melt passage/bifurcated pipeline
6 Feeding passage part/feeding pipeline part
7.1 Discharging passage part/discharging pipeline part
7.2 Discharging passage part/discharging pipeline part
8 Branched junction

9 Inlet

10 Outlet

[0066] 11 Cylindrical passage section
12 Straight line
13 Straight line
14.1 Extruder/melt conveyor
14.2 Extruder/melt conveyor
14.3 Extruder/melt conveyor
15 Multilayer extrusion head
16 Assembly unit
17 Multiple extrusion head
18 Upstream section
19 Downstream section
20.1 Ring segment
20.2 Ring segment
20.3 Ring segment
W Center angle

[0067] State of the Art (FIG. 1)

30 Melt distributor
31.1 Bifurcated pipeline
31.2 Bifurcated pipeline
31.3 Bifurcated pipeline
32 Upper plate
33 Lower plate
34 Separating plane
35 Feeding pipeline part
36.1 Discharging pipeline part
36.2 Discharging pipeline part

37 Junction