WO2005045104A1

WO2005045104A1 - Spinning head and filter device for said type of spinning head

Info

Publication number: WO2005045104A1
Application number: PCT/EP2004/011198
Authority: WO
Inventors: Andreas May; Stefan Becker; Markus Reichwein
Original assignee: Saurer Gmbh & Co. Kg
Priority date: 2003-10-21
Filing date: 2004-10-07
Publication date: 2005-05-19
Also published as: EP1678354A1; CN1863947A; TWI368677B; CN1863947B; DE10348766A1; TW200517534A; EP1678354B1

Abstract

The invention relates to a spinning head which is used to melt spin a plurality of synthetic filaments, and to a filter device for said type of spinning head. A filter device is arranged between an inlet plate comprising a melt inlet and a die base comprising several die holes, said filter device comprising a cylindrically-shaped filter ring element which can be cross-flown from the outside to the inside. A separate second filter ring element is associated with the first filter ring element in order to form a sufficient filter surface with large melt through-put rates, said second ring element being arranged at a distance in relation to the outer lying first filter ring element. A first partial flow of the melt is guided through the first filter ring element from the outside to the inside and a second partial flow of the melt is guided through the second filter ring element from the inside to the outside in order to combine them together in a release chamber formed between the filter ring elements.

Description

Spinning head and filter device for such a spinning head

The invention relates to a spinning head for melt spinning a plurality of synthetic filaments according to the preamble of claim 1 and a filter device for a spinning head according to the preamble of claim 12.

A generic spinning head and a generic filter device are known from EP 1 093 535 B1.

When polymer melts are extruded, the melt is filtered before it passes through a large number of nozzle bores in a nozzle plate inside the spinning head. For this purpose, the known spinning head has a filter device which contains a cylindrical filter ring element. The filter ring element is formed by a support tube and a filter jacket surrounding the support tube, the support tube and the filter jacket being joined to form a sealing edge on the support ends. The filter ring element is held in a self-sealing manner within the spinning head by a distributor piece, the melt flow flowing through the circumference of the filter ring element flowing through the filter jacket from the outside inwards. Spinning heads and filter devices of this type have proven themselves in the spinning of synthetic fibers for textile applications. However, there are natural limits in terms of melt throughput and service life, which an application for melt spinning synthetic fibers for technical applications with high melt throughputs only permits to a limited extent.

In order to provide correspondingly large filter areas for the realization of high melt throughputs, spinning heads with filter devices are known, for example, from US 4,405,548 or DE 199 15 700 AI (US 6,171,536), which are based on an annular filter element, the filter elements being U-shaped or have a V-shaped cross section. However, such filter devices have the disadvantage that the filter elements are not can be held self-sealing in the spinning head, so that a special sealing effort is inevitable when using the known filter device. In contrast, EP 0 178 570 AI discloses a spinning head and a filter device in which the filter device is formed by a plurality of individual filters used in a circular arrangement. In this case, a plurality of individual feed elements must be arranged sealingly between the melt inlet and the nozzle bores, so that the sealing requirements increase even further.

In the known solutions, in which profiled filter elements are used, there is also the problem that the flow characteristics over the entire surface of the filter element are different due to the shape of the filter elements, so that preferred flow ranges arise, which then lead to uneven use of the filter material. There is no uniform melt flow within the spinning head.

The invention is based on the object of equipping a spinning head of the type mentioned at the outset with the greatest possible filter capacity and at the same time avoiding the disadvantages mentioned.

Another object of the invention is to provide a filter device which is particularly suitable for high melt throughputs and which is suitable for self-sealing assembly in a spinning head.

For a spinning head, the object according to the invention is achieved in that a separate second filter ring element is provided, which is arranged at a distance from the first filter element located on the outside and from the inside to the outside can be flowed through, a delivery space being formed between the two filter ring elements.

For a filter device, the object of the invention is achieved in that the filter ring element is assigned a second filter ring element with a smaller diameter at a distance, through which a partial flow of the melt flow flows from the inside to the outside, that the support ends of the filter ring elements are designed to be concentric sealing edges, and that both Filter ring elements have an essentially equal stiffness.

The arrangement and design of the two filter ring elements according to the invention has the consequence that a uniform, homogenized melt flow for melt spinning is achieved at high melt throughput rates. The flow through each of the filter ring elements is very even. The nested design of the filter ring elements also leads to a compact design. Due to the substantially equal stiffness of the filter ring elements, a common fixation within the spinning head is possible without the risk of local leaks.

In order to fix the filter ring elements to one another, the development of the invention in which a distributor ring is assigned to the filter ring elements has proven particularly useful. Here, the distributor ring contains a distributor head, which abuts an upper support end of the filter ring elements, and a distributor collar, which projects into the delivery space between the filter ring elements. In the case of a self-sealing arrangement of the filter device within the spinning head, the distributor ring is kept movable.

The distributor ring is thus particularly suitable, on the one hand, to form a seal between the distributor head and the upper support ends of the filter ring elements, and on the other hand to seal off the dispensing space from the melt inlet Increase the stability of the filter ring elements to ensure radial support. For this purpose, the distributor collar has a plurality of webs distributed around its circumference on both sides, which abut the filter ring elements.

To ensure centering, in particular on a movably held distributor ring, according to an advantageous development of the invention, a holding plate is provided between the inlet plate and the nozzle plate, by means of which a support for the lower support ends of the filter ring elements is formed.

It is particularly advantageous here if the holding plate has an annular distributor chamber above the support, in which the filter ring elements are held. Thus, by shaping the walls of the distributor chamber, an optimized melt feed to the individual filter ring elements can be carried out. The supply of melt from the melt inlet to the distributor chamber can advantageously take place through an outer ring channel and an inner ring channel which is formed between the distributor ring and the holding plate at the opposite support end of the filter ring elements.

The holding plate can also be used to distribute the melt to the individual nozzle bores of the nozzle plate after it has left the discharge space. For this purpose, at least one distributor groove is formed on the underside of the holding plate. The distributor groove can be expanded to form a groove system by additional partial grooves, so that both annular and circular nozzle bore arrangements in the nozzle plate can be supplied with a melt evenly.

However, it is also possible to arrange an additional distributor plate between the holding plate and the nozzle plate, through which the distribution of the melt is carried out. In order to achieve sufficient pressure stability with favorable flow properties, the filter ring elements are preferably each formed by a support cylinder with fluid passages on the wall and a filter jacket. Here, the outer support cylinder with the outer filter jacket and the inner support cylinder with the inner filter jacket are each connected to a unit. The desired rigidity can be influenced by the fluid passages in the support cylinder on the wall side. The size and the number of fluid passages can be designed differently for the two filter ring elements.

The outer filter jacket and the inner filter jacket are preferably formed by a pleated filter material in order to obtain the largest possible filter area. The pleated filter material can advantageously be formed as a wire mesh or a fleece.

Further advantages of the invention are described below with reference to some embodiments of the spinning head according to the invention and an exemplary embodiment of the filter ring element with reference to the accompanying drawings.

They represent:

1 shows schematically a longitudinal sectional view through a spinning head according to the invention with a filter device according to the invention;

Fig. 2 schematically shows a longitudinal section of the filter device according to the invention from the embodiment of the spinning head according to Fig. 1;

Fig. 3 schematically shows a cross section of the filter device according to the invention from the embodiment of the spinning head according to Fig. 1; 4 schematically shows a longitudinal sectional view of a further exemplary embodiment of the spinning head according to the invention.

In Fig. 1, a first exemplary embodiment of the spinning head according to the invention is shown schematically in a longitudinal sectional view. The spinning head has a cylindrical housing 1. On the underside of the housing 1, an inner housing collar 7 is formed. On the housing collar 7 there is a nozzle plate 5 guided inside the housing 1. The nozzle plate 5 has a plurality of nozzle bores 6> on its underside, which are connected to the top of the nozzle plate 5 by nozzle channels 35.

At the upper end of the housing 1, an internal thread 8 is formed, through which an inlet plate 2 is guided inside the housing 1. The inlet plate 2 has a central one. Melt feed 3, which is connected to a melt line, not shown here. The melt inlet 3 is connected to the underside of the inlet plate 2 via inlet channels 23.

Between the inlet plate 2 and the nozzle plate 5, a filter device 4 is formed within the housing 1, through which the inlet channels 23 formed in the inlet plate 2 are connected to the nozzle channels 35 of the nozzle plate 5.

A holding plate 17 is arranged between the inlet plate 2 and the nozzle plate 5 for receiving and holding the filter device 4. The inlet plate 2 is inserted into the housing 1 such that the sealing gaps between the nozzle plate 5 and the holding plate 17 and between the inlet plate 2 and the holding plate 17 are sealed. An annular distributor chamber 18 is formed in the holding plate 17 and is connected via a passage 32 to a distributor groove 19 on the underside of the holding plate 17. The passage 32 is also annular. For this purpose, the holding plate 17 consists of an outer and an inner half. Symmetrical to the passage 32 is a first one, outer filter ring element 9 and a second, inner filter ring element 10 arranged within the distribution chamber 18. The structure of the filter ring elements 9 and 10 is described in more detail below. The outer filter ring element 9 and the inner filter ring element 10 are cylindrical and are arranged at a distance from one another. A distribution ring 12 bears against an upper support end 15. The distributor ring 12 is formed by the distributor head 13 formed outside the filter ring elements 9 and 10 and the distributor collar 14 projecting between the filter ring elements 9 and 10. The distributor ring 12 is supported on the upper side of the holding plate 17 to the opposite inlet plate 2 by a spring element 25. The distributor head 13 extends essentially over the entire opening cross section of the distributor chamber 18 within the holding plate 17, an inner ring channel 21 formed between the holding plate 17 and the distributor ring 12 on the inner circumference of the distributor head 13 and an intermediate ring on the outer circumferential side of the distributor head 13 the outer ring channel 20 formed are arranged in the distributor ring 12 and the holding plate 17. An inlet chamber 22, in which the inlet channels 23 open, is formed above the distributor head 13 on the underside of the inlet plate 2. Through the outer ring channel 20 and the inner ring channel 21, the inlet chamber 22 is connected to the distribution chamber 18, which is divided into an outer and an inner half by the filter ring elements 9 and 10.

A discharge space 11 is formed between the filter ring elements 9 and 10, the lower support ends 16 of the filter ring elements 9 and 10 being supported on the holding plate 17 at the lower end of the distribution chamber 18. The distributor collar 14 of the distributor ring 12 protruding into the discharge space 11 has a plurality of webs 24 on its inner and outer longitudinal sides, through which the filter ring elements 9 and 10 are supported radially. In operation, a melt of a polymer is fed to the spinning head under pressure via the melt feed 3. The melt reaches the feed chamber 22 via the feed channels 23. A part of the flow of the melt flow passes through the outer ring channel 20 into the outer half of the distribution chamber 18 from the feed chamber 22 and a second part of the melt flow flows into the inner ring channel 21 Half of the distribution chamber 18. A resulting compressive force is generated on the distributor ring 12, which presses the distributor ring 12 in the direction of the nozzle plate 5. Thus, the lower support end 16 of the filter ring elements 9 and 10 is pressed against the support of the holding plate 17 and the upper support end 15 against the underside of the distributor head 13. The sealing edges formed on the support ends 15 and 16 thus lead to a seal between the distributor chamber 18 and the delivery space 11. The filter ring elements 9 and 10 are flowed through uniformly. A partial flow flowing from the outside of the distribution chamber 18 inwards in the direction of the discharge space 11 acts on the outer filter ring element 9. On the other hand, an opposite partial flow acts on the inner filter ring element 10, which flows from the inside out of the distribution chamber 18 to the outside in the direction of the discharge space 11. In the delivery space 11, the partial flows are brought together via the distributor collar 14 and guided into the distributor groove 19 via the passage 32. The melt reaches the nozzle channels 35 from the distributor groove 15 in order to be extruded through the nozzle bores 6 as a plurality of synthetic filaments.

In order to be able to offer a uniform flow on the one hand and the largest possible filter area on the other hand, the filter ring elements 9 and 10 can be designed according to the following exemplary embodiment. 2 and 3, a filter device according to the invention for a spinning head is shown schematically in several views. 2 schematically shows a longitudinal section and FIG. 3 schematically shows a cross section. So far no explicit reference is made to one of the figures, the following description applies to both figures.

The filter device has an outer filter ring element 9 and an inner filter ring element 10 with a smaller diameter. The diameter of the two filter ring elements 9 and 10 is selected such that there is a sufficient distance between the filter ring elements 9 and 10 to form a delivery space 11. The fixing and assignment of the filter ring elements 9 and 10 is preferably achieved by a distributor ring 12. The distributor ring 12 is shown in dashed lines in FIGS. 2 and 3. The assignment and fixing of the filter ring elements in FIGS. 9 and 10 can, however, also be achieved by other equivalent means.

The outer filter ring element 9 is formed by a support cylinder 26 and a filter jacket 29 surrounding the support cylinder 26. The support cylinder 26 and the filter jacket 29 are each joined together at the upper support end 15 and at the lower support end 16 and each form a circumferential sealing edge 31. The support cylinder 26 has a plurality of fluid passages 27. Such a filter ring element is known for example from EP 1 093 535, so that reference can be made here.

The filter jacket 29 is preferably formed by a pleated filter material.

The inner filter ring element 10 is constructed identically to the outer filter ring element 9 with the only difference that an inner filter jacket 30 is arranged on the support cylinder 28. The inner filter jacket 30 and the support cylinder 28 are also joined together at the support ends 15 and 16 to form a sealing edge 31. With reference to the above, further explanation about the inner filter ring element 10 can be dispensed with. The formation of the fluid passages 27 in the support cylinders 26 and 28 are selected in particular with a view to an essentially uniform axial rigidity of the filter ring elements 9 and 10. However, it is also possible to vary the wall thickness of the support cylinders 26 and 28 in consideration of the fluid passages 27 in order to equalize an axial rigidity. In operation, the support cylinders 26 and 28 are supported by the distributor ring 12. As shown in dashed lines in FIG. 3, the distributor ring 12 on its collar which grips between the support cylinders 26 and 28 has on both sides a plurality of webs 24 which bear against the support cylinders 26 and 28. The intermediate space between the webs 24 forms the delivery space 11.

The filter device shown in FIGS. 2 and 3 is thus suitable for bringing two partial melt streams together after the filtration. Here, an external partial melt flow can be conducted from the outside in and an internal partial melt flow from the inside to the outside. The sealing edges 31 formed on the support ends 15 and 16 ensure a self-sealing insert within the spinning head.

4 shows a further exemplary embodiment of a spinning head according to the invention schematically in a longitudinal section. The components with the same function were identified with identical reference symbols.

The exemplary embodiment according to FIG. 4 is essentially identical to the previous exemplary embodiment according to FIG. 1, so that only the differences are explained at this point.

In the housing 1, a nozzle plate 5 is arranged on the underside, which has a circular arrangement of nozzle bores 6. A holding plate 17 is arranged between the nozzle plate 5 and the inlet plate 2 and an additional distribution plate 33 is arranged between the holding plate 17 and the nozzle plate 5. The holding plate 17 has an annular distributor chamber 18 which over a Passage 32 is connected to the underside of the holding plate 17. The passage 32 is in this case carried out through a plurality of bores formed in a circular arrangement, so that the holding plate consists of one part. The filter ring elements 9 and 10 are symmetrical to the passage 32 by means of a distributor ring 12 arranged at the upper support end 15. The distributor ring 12 is formed here by a distributor collar 14 and a plate-shaped distributor head 13. An inlet chamber 22 is formed above the distributor ring 12 in the inlet plate 6 and is connected to the outer and inner half of the distributor chamber 18 by an outer ring channel 20 and by a plurality of inlet channels 36.

The distributor plate 33, which has a plurality of distributor grooves 19 and distributor bores 34, is arranged below the holding plate 17. The groove and bore system within the manifold plate 33 is exemplary. Here, the melt discharged from the discharge space 11 through the passage 32 is evenly distributed over the nozzle channels 35 of the nozzle plate 5.

The function of the exemplary embodiment of a spinning head shown in FIG. 4 is identical to the previous exemplary embodiment, so that no further explanation is given here.

The exemplary embodiments according to FIGS. 1 and 4 represent a preferred variant of the spinner head according to the invention with a self-sealing filter device. However, the spinner head according to the invention can also be advantageously designed with the variants in which the filter device is not self-sealing but rather is produced by, for example, clamping forces. LIST OF REFERENCE NUMBERS

Housing inlet plate melt inlet filter device nozzle plate nozzle bores housing collar thread outer filter ring element inner filter ring element delivery space distributor ring distributor head distributor collar upper support end lower support end

Retaining plate

distribution chamber

Distributor groove outer ring channel inner ring channel

inlet chamber

inlet channel

Stege

Spring element outer support cylinder

Fluid passages inside support cylinder outer filter jacket inner filter jacket

sealing edge

passage

distribution plate

distributor bores

nozzle channel

inlet channel

Claims

claims

1. Spinning head for melt spinning a plurality of synthetic filaments with a housing (1) for receiving an inlet plate (2) with a melt inlet (3) and a nozzle plate (5) with a plurality of nozzle bores (6) and with one between the inlet plate (2 ) and the nozzle plate (5) arranged filter device (4), which has a cylindrical filter ring element (9) through which flows from the outside in, characterized in that a separate second filter ring element (10) is provided, which is spaced apart from the outer first filter ring element (9) is arranged and can be flowed through from the inside to the outside, a delivery space (11) being formed between the two filter ring elements (9, 10).

2. Spinning head according to claim 1, characterized in that a distributor ring (12) is assigned to the filter ring elements (9, 10), which rests with a distributor head (13) on an upper supporting end (15) of the filter ring elements (9, 10) and which projects with a distributor collar (14) between the filter ring elements (9, 10).

3. Spinning head according to claim 2, characterized in that the distributor head (13) and the upper support ends (15) of the filter ring elements (9, 10) form a seal of the discharge space (11) with respect to the melt inlet (3).

4. Spinning head according to claim 2 or 3, characterized in that the distributor collar (14) on the sides facing the filter ring elements (9, 10) has a plurality of webs (24) for radially supporting the filter ring elements (9, 10).

5. Spinning head according to one of the preceding claims, characterized in that a holding plate (17) is provided which is arranged between the inlet plate (2) and the nozzle plate (5) and which supports the lower support ends (16) of the filter ring elements (9, 10). forms.

6. Spinning head according to claim 5, characterized in that the holding plate (17) above the support has an annular distributor chamber (18) in which the filter ring elements (9, 10) are held, between the distributor head (13) and the holding plate ( 17) at the end of the distribution chamber (18) an outer ring channel (20) and an inner ring channel (21) are formed, through which the distributor chamber (18) is connected to the melt inlet (3).

7. Spinning head according spoke 5 or 6, characterized in that the holding plate (17) below the support has a distributor groove (19) through which the delivery space (11) with the nozzle bores (6) of the nozzle plate (5) is connected.

8. Spinning head according to one of claims 5 to 7, characterized in that the holding plate (17) is formed in two parts by an outer section and an inner section.

9. Spinning head according to one of the preceding claims, characterized in that the outer filter ring element (9) is formed by a support cylinder (26) with wall-side fluid passages (27) and an outer filter jacket (29), the support cylinder (26) and the filter jacket (29) are joined together at the support ends (15, 16).

10. Spinning head according to one of claims 1 to 9, characterized in that the inner filter ring element (10) by a support cylinder (28) with wall-side fluid passages (27) and an inner filter jacket (30) is formed, the support cylinder (28) and the filter jacket (30) being joined together at the support ends (15, 16).

11. Spinning head according to one of claims 1 to 10, characterized in that the filter ring elements (9, 10) on the support ends (15, 16) are held in a self-sealing manner between the distributor ring (12) and the holding plate (17).

12. Filter device for a spinning head, in which a melt flow is passed through a cylindrical filter ring element (9) from the outside inwards and in which the filter ring element (9) with an upper support end (15) and a lower support end (16) self-sealing within the spinning head , characterized in that the filter ring element (9) is assigned a second filter ring element (10) with a smaller diameter at a distance, through which a partial flow of the melt flow flows from the inside to the outside, so that the support ends (15, 16) of the filter ring elements ( 9, 10) are formed into concentric sealing edges (31) and that both filter ring elements (9, 10) have an essentially equally high stiffness.

13. Filter device according spoke 12, characterized in that the filter ring elements (9, 10) are each formed by a support cylinder (16, 28) with wall-side fluid passages (27) and a filter jacket (29, 30), the outer support cylinder (26 ) are connected to the outside filter jacket (29) and the inner support cylinder (28) to the inside filter jacket (30).

14. Filter device according spoke 13, characterized in that the outer filter jacket (29) and the inner filter jacket (30) are each formed by a pleated filter material.

15. Filter device according to one of claims 12 to 15, characterized in that the filter ring elements (9, 10) are combined with a distributor ring (12) which has a distributor collar (14) for supporting the filter ring elements (9, 10).

16. A method for melt spinning a plurality of synthetic filaments from a plastic melt, in which the melt is filtered before extruding, characterized in that the melt is divided into two partial streams before filtering, that the partial streams are filtered by two separate filter elements and that the partial streams are brought together before extrusion.