U.S. patent application number 10/213806 was filed with the patent office on 2003-02-20 for spinning apparatus.
Invention is credited to Beck, Arnold, Brandt, Holger, Dreyer, Joachim, Rave, Henning, Schirber, Oliver.
Application Number | 20030035855 10/213806 |
Document ID | / |
Family ID | 7695888 |
Filed Date | 2003-02-20 |
United States Patent
Application |
20030035855 |
Kind Code |
A1 |
Brandt, Holger ; et
al. |
February 20, 2003 |
Spinning apparatus
Abstract
A spinning apparatus for extruding a group of filaments by means
of an annular spinneret. An annular collection chamber is arranged
upstream of the spinneret, which is provided with a plurality of
nozzle bores. The collection chamber has an upper inlet area and a
lower annular outlet area, which is connected to the upper inlet
area. In the inlet area of the collection chamber a filter device
is disposed, upstream of which is a melt feed. The inlet area of
the collection chamber is formed by a plurality of filter chambers,
which are each provided with a melt inlet and a melt outlet. The
filter device has a plurality of substantially cylindrical filter
elements, which are each provided with a powdered filter medium.
One of these filter elements is assigned to each filter chamber.
This ensures a large filtration area and deep bed filtration of the
polymer melt.
Inventors: |
Brandt, Holger; (Ehndorf,
DE) ; Rave, Henning; (Leezen, DE) ; Beck,
Arnold; (Neumunster, DE) ; Dreyer, Joachim;
(Aukrug, DE) ; Schirber, Oliver; (Neumunster,
DE) |
Correspondence
Address: |
SMITH MOORE LLP
P.O. BOX 21927
GREENSBORO
NC
27420
US
|
Family ID: |
7695888 |
Appl. No.: |
10/213806 |
Filed: |
August 6, 2002 |
Current U.S.
Class: |
425/382.2 ;
425/464 |
Current CPC
Class: |
D01D 4/06 20130101; D01D
4/00 20130101; D01D 1/106 20130101 |
Class at
Publication: |
425/382.2 ;
425/464 |
International
Class: |
D01D 001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 18, 2001 |
DE |
101 40 581.2 |
Claims
What is claimed is:
1. Spinning apparatus for extruding a group of filaments
comprising: an annular spinneret comprising a plurality of nozzle
bores; an annular collection chamber arranged upstream of the
spinneret comprising: an upper inlet area; and a lower annular
outlet area connected to the upper inlet area; a filter device
arranged in the inlet area of the collection chamber; and a melt
feed arranged upstream of the filter device; wherein the inlet area
of the collection chamber is formed by a plurality of filter
chambers each having a melt inlet and a melt outlet; wherein the
filter device comprises a plurality of substantially cylindrical
filter elements which each comprise a powdered filter medium; and
wherein each one of the filter elements is assigned to one of the
filter chambers.
2. Spinning apparatus as claimed in claim 1: wherein the filter
elements are each formed as a hollow cylinder with an outlet
opening that is connected to the melt outlet of the filter chamber;
wherein the filter elements each have a filter shell comprising the
powdered filter medium through which melt flows from the outside
toward the inside; and wherein a space is formed between the filter
shell of the filter element and the filter chamber.
3. Spinning apparatus as claimed in claim 2: wherein the filter
shell is formed by an inner tube that is open toward the outlet
opening and an outer tube that encloses the inner tube; wherein a
closed shell casing exists between the inner tube and the outer
tube to receive the powdered filter medium; and wherein the inner
tube and the outer tube each have a plurality of passages.
4. Spinning apparatus as claimed in claim 1, wherein the powdered
filter material is a sand or a metal powder.
5. Spinning apparatus as claimed in claim 1, wherein the filter
chambers are annularly spaced apart from one another within the
inlet area and wherein the melt outlets of the filter chambers open
directly into the outlet area of the collection chamber.
6. Spinning apparatus as claimed in claim 1, wherein the melt
inlets of the filter chambers are connected to the melt feed by a
plurality of distribution lines.
7. Spinning apparatus as claimed in claim 1, wherein the melt
inlets of the filter chambers are connected to the melt feed by an
annular distribution channel.
8. Spinning apparatus as claimed in claim 1, wherein an annular
perforated plate is arranged upstream of the spinneret within the
outlet area.
9. Spinning apparatus as claimed in claim 1, wherein the spinneret
and the filter device are held by an annular carrier and wherein a
heating element is arranged on the inside of the carrier.
10. Spinning apparatus as claimed in claim 9, wherein the heating
element is an electric heater band.
11. Spinning apparatus as claimed in claim 9, wherein the carrier
is connected to a heating box such that a shell of the carrier and
an upper end face of the carrier can be heated by a heat transfer
fluid.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to a spinning apparatus for extruding
a group of filaments comprising an annular spinneret.
[0002] An example of a spinning apparatus is disclosed in U.S. Pat.
No. 6,171,536.
[0003] This prior art spinning apparatus has an annular spinneret
on an underside with a plurality of nozzle bores through which a
polymer melt is extruded into strand-like filaments. Such spinning
apparatus' are used in staple fiber plants. The group of filaments
is combined into a filament bundle after cooling. To enable uniform
extrusion of the polymer melt, the polymer melt is filtered
immediately prior to extrusion to ensure its purity and
homogeneity. For this purpose, the prior art spinning apparatus
comprises an annular collection chamber with an outlet area
directly in front of the spinneret and an upper inlet area. In the
inlet area, a filter device is arranged comprising an annular
filter element with an approximately U-shaped cross section. For
this purpose, an outer and an inner screen wall are joined at one
end and inserted into the annular inlet area of the collection
chamber. The opposite ends of the screen walls form the melt inlet
of the collection chamber.
[0004] Although the filter device used in the prior art spinning
apparatus permits an enlargement of the filtration area, it has the
significant drawback that no deep action can be achieved by means
of the screen wall. The result is a shorter tool life and
decreasing throughputs due to the increasing degree of
contamination.
[0005] Another drawback of the prior-art spinning apparatus is that
the high melt pressure requires correspondingly strong side walls
of the collection chamber to realize the nozzle diameter.
[0006] European Application 0 178 570 A1 discloses a spinning
apparatus in which a plurality of filter candles are used to filter
a polymer melt prior to extrusion through a spinneret. The
drawbacks of this apparatus are that the spinning apparatus is
completely unsuitable for extruding an annular group of filaments
required for staple fiber production and the deep action of the
filter candles is insufficient.
[0007] Accordingly, there is a need in the art for a spinning
apparatus for extruding a group of filaments with an annular
spinneret in such a way that prior to extrusion the polymer melt is
filtered under the action of large filtration areas and deep bed
filtration.
BRIEF SUMMARY OF THE INVENTION
[0008] The present invention fulfills this need by providing a
spinning apparatus wherein the inlet area of the collection chamber
is formed by a plurality of filter chambers, each provided with a
melt inlet and a melt outlet, and the filter device has a plurality
of substantially cylindrical filter elements, each provided with a
powdered filter medium. One filter element is assigned to each
filter chamber.
[0009] The present invention is based on substantially cylindrical
filter elements, each of which is provided with a powdered filter
medium in order to obtain sufficient deep bed filtration.
Furthermore, the pressure load in the filter chambers is very small
due to the relatively small diameters of the filter chambers in the
region of the filter device.
[0010] A particularly advantageous further development of the
invention provides that the filter elements are each formed as
hollow cylinders with an outlet opening that communicates with the
melt outlet of the filter chamber. The filter elements each have a
filter shell made of the powdered filter medium through which the
molten material flows from the outside toward the inside. A space
is formed between the filter shell of the filter element and the
filter chamber. This ensures a uniform inflow of the polymer melt
over the circumference of the filter element. Due to the hollow
cylindrical configuration of the filter element, the paths traveled
by the polymer melt within the filter element are equally long in
radial direction irrespective of the entry of the polymer melt.
This has the advantage that equal retention times are obtained.
[0011] A particularly simple and effective construction of the
filter element of the present invention is also provided. The
filter shell is formed by an inner tube that is open toward the
outlet opening and an outer tube that encloses the inner tube. A
closed annular shell casing is arranged between the inner tube and
the outer tube to receive the powdered filter medium. In the inner
tube and the outer tube, a plurality of passages is provided to
allow the polymer melt to enter and exit. An additional screen
cover may be arranged along the circumference of the inner tube
and/or the outer tube.
[0012] The filter medium is preferably formed by a metal powder or
a sand, e.g. a silica sand.
[0013] In principle, however, the shell casing formed between the
inner tube and the outer tube can be filled with any type of filter
medium.
[0014] To obtain a uniform melt feed of the filtered melt over the
entire annular cross section of the spinneret, the filter chambers
are arranged annularly spaced apart from one another such that the
melt outlets of the filter chambers open directly into the outlet
area of the collection chamber.
[0015] The melt feed can advantageously be connected with the melt
inlets of the filter chambers by a plurality of distribution
channels, or it can be connected with the melt inlets of the filter
chambers by an annular distribution channel. It is essential that
between the melt feed and the melt inlets of the filter chambers,
paths of equal length are formed by the distribution channels to
avoid different retention times of the polymer melt within the
spinning apparatus.
[0016] In a particularly advantageous further development of the
invention an annular perforated plate is arranged in the outlet
area of the collection chamber upstream of the spinneret to achieve
better mixing of the melt streams exiting from the melt outlets of
the filter chambers in the outlet area of the collection
chamber.
[0017] To supply a cooling air stream required to cool the group of
filaments, the spinneret and the filter device are held by an
annular carrier. The melt-carrying parts of the spinning apparatus
are heated by a heating element arranged on the inside of the
carrier. The heating elements used for this purpose are preferably
electric heater bands.
[0018] The remaining areas of the carrier can advantageously be
heated by means of a heat transfer fluid. The shell of the carrier
and the end face of the carrier are connected with a heating box
that contains the heat transfer fluid.
BRIEF DESCRIPTION OF THE FIGURES
[0019] An exemplary embodiment of the inventive spinning apparatus
will now be described in greater detail with reference to the
attached drawings in which:
[0020] FIG. 1.1 is a schematic sectional view taken in longitudinal
direction of the spinning apparatus according to a first embodiment
of the present invention;
[0021] FIG. 1.2 is a schematic cross section of the spinning
apparatus according to the first embodiment of the present
invention;
[0022] FIG. 1.3 depicts an enlarged detail of the sectional view of
FIG. 1.1.
[0023] FIG. 2 is a schematic sectional view of a second embodiment
of the spinning apparatus according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Unless express reference is made to one of the figures, the
following description applies to all of the figures.
[0025] The spinning apparatus of the present invention comprises a
heated carrier 17. The heating elements required to heat carrier 17
are not depicted. Carrier 17 serves to receive an annular spinneret
1, which is mounted to the underside of carrier 17. Spinneret 1 has
a plurality of nozzle bores 5. Above spinneret 1, an annular
collection chamber is formed, which comprises a lower annular
outlet area 2.2 and an upper inlet area 2.1. The outlet area 2.2 of
the collection chamber is annular and covers the entire surface of
spinneret 1. Within the outlet area 2.2, a perforated plate 16 and
an intermediate plate 29 are arranged. Perforated plate 16
comprises a plurality of vertical bores 32 through which an annular
chamber 33 formed between spinneret 1 and perforated plate 16 is
connected with the remaining sections of outlet area 2.2 of the
collection chamber. The intermediate plate 29 forms the connection
between the inlet area 2.1 and the outlet area 2.2 of the
collection chamber.
[0026] The inlet area 2.1 of the collection chamber is formed by a
plurality of filter chambers 3 that are spaced apart from one
another. In a preferred embodiment, a total of eleven filter
chambers 3 are introduced into carrier 17 so as to be uniformly
distributed over the annual cross section of outlet area 2.2. The
number of filter chambers 3 is given by way of example. Filter
chambers 3 each have an upper melt inlet 7 and a lower melt outlet
8. Melt outlets 8 of filter chambers 3 are formed in accordance
with the partitioning of the filter chamber arrangement in the
intermediate plate 29.
[0027] The inlet area 2.1 of the collection chamber serves to
receive a filter device. The filter device comprises a plurality of
filter elements 4, each of which are arranged in a filter chamber
3. Filter elements 4, of which there is a total of eleven in a
preferred embodiment, are hollow and cylindrical and have a
permeable filter shell 11. The diameter of filter shell 11 is
selected in such a way that a gap is formed between the wall of
filter chamber 3 and filter element 4.
[0028] Filter element 4 has an inner tube 12, which is closed at
one end and open at the opposite end. The open end of the inner
tube 12 forms the outlet opening 10 of the filter element, which is
connected with the melt outlet 8 of filter chamber 3. Along the
circumference of the inner tube 12, at its open end, a
circumferential collar 31 is formed, which in axial direction rests
against intermediate plate 29 and in radial direction against
carrier 17 forming a seal. On the side of collar 31 opposite
intermediate plate 29, an outer tube 13 rests against collar 31.
This outer tube 13 encloses the inner tube 12 at a distance and
extends up to the closed end of inner tube 12. At the closed end of
inner tube 12 a cover 24 is provided which connects the inner tube
12 with the outer tube 13. This creates a closed annular shell
casing into which a powdered filter medium 9 is introduced. Outer
tube 13, inner tube 12 and cover 24 have a plurality of passages
14. Filter element 4 is inserted upright in filter chamber 3.
Collar 31 forms a partition in filter chamber 3 between melt inlet
7 and melt outlet 8.
[0029] The filter elements 4 of the filter device are preferably
configured identically to achieve uniform filtration of the
melt.
[0030] The melt inlets 7 of filter chambers 3 are connected with a
melt feed 6. For this purpose, a distribution line system is
provided, assigning a separate distribution line 15 to each
individual filter chamber 3. This distribution line system is
supplied by a spin pump 21. Spin pump 21 is connected with a melt
generator, e.g. an extruder.
[0031] In the embodiment of the spinning apparatus shown in FIG. 1,
a polymer melt stream is supplied by spin pump 21 to distribution
lines 15. Distribution lines 15 each feed a partial melt stream to
one of the melt inlets 7. Thus, a partial polymer melt stream
enters into each of the filter chambers 3. In filter chamber 3, the
polymer melt is distributed over the entire circumference of filter
shell 11 and penetrates through passages 14 of outer tube 13 into
filter shell 11. The polymer melt passes through the powdered
filter medium 9 and via passages 14 of inner tube 12 is guided into
a central melt channel 30. From this central melt channel 30 the
partial stream reaches melt outlet 8 of filter chamber 3 via outlet
opening 10. From melt outlet 8 the partial melt stream passes into
outlet area 2.2 of the collection chamber. All the partial streams
flowing through filter chambers 3 are combined in outlet area 2.2.
The polymer melt is then guided through bores 32 of perforated
plate 16, such that additional mixing takes place in annular
chamber 33 between perforated plate 16 and spinneret 1. The polymer
melt is then extruded through nozzle bores 5 of spinneret 1. A
group of filaments is created resulting in a closed filament
curtain corresponding to the annular arrangement of the
spinneret.
[0032] To filter the polymer melt, filter elements 4 preferably
contain metal powder or a silica sand in filter shell 11. This
ensures deep action during filtration of the polymer melt. In
addition, filter shell 11 is constructed and integrated in filter
chamber 3 in such a way that the retention times of the polymer
melt during filtration are substantially independent of the entry
location. Furthermore, relatively high differential pressures can
be realized during filtering of the polymer melt. The pressure load
is limited to the diameter of filter chambers 3, which is small
compared to that of the spinneret.
[0033] The construction of the filter element in the embodiment
shown in FIG. 1 is only an example. It is possible, for instance,
to arrange additional filter screens in the inner and outer region
of the tubes. It is also possible to use any type of filter medium
in the shell casing.
[0034] FIG. 2 depicts a further embodiment of the inventive
spinning apparatus. Components with like function are provided with
identical reference numerals. The construction of the embodiment
according to FIG. 2 is substantially identical to that of the
preceding embodiment, so that only the significant differences will
be described below.
[0035] The embodiment of the spinning apparatus according to FIG. 2
has an annular carrier 17. This annular carrier 17 is integrated in
a heating box 20 such that shell 27 of carrier 17 and the upper end
face 28 of carrier 17 can be heated by a heat transfer medium
contained in heating box 20. In its center, carrier 17 forms a seat
34 for a cooling device (not depicted). On the inside 18 of carrier
17, a heating element 19 is arranged. Heating element 19 is
preferably embodied as a heater band, which heats the entire
interior 18 of carrier 17.
[0036] Carrier 17 serves to hold a spinneret 1, a perforated plate
16, an intermediate plate 29 and a plurality of filter elements 4.
The arrangement and configuration of spinneret 1, perforated plate
16, intermediate plate 29 and filter elements 4 is identical to the
embodiment shown in FIG. 1, so that reference is made to the
preceding description.
[0037] Melt inlets 7 of filter chambers 3 are connected with an
annular distribution channel 22. Distribution channel 22 is
connected with a spin pump 21 and a melt feed 6 via one or more
melt lines 23. Distribution channel 22, melt lines 23 and spin pump
21 are arranged in heating box 20 and are heated.
[0038] In contrast to the preceding embodiment of the spinning
apparatus, a polymer melt is first conveyed into the annular
distribution channel 22 via spin pump 21. From distribution channel
22 the polymer melt enters into the associated filter chambers 3 in
respective partial streams. After filtering, the partial streams
are combined again and mixed in the outlet area of collection
chamber 2.2. After passing through perforated plate 16, the polymer
melt is extruded by means of spinneret 1 to form the plurality of
filaments.
LIST OF REFERENCE NUMERALS
[0039] 1 spinneret
[0040] 2 collection chamber
[0041] 2.1 inlet area
[0042] 2.2 outlet area
[0043] 3 filter chamber
[0044] 4 filter element
[0045] 5 nozzle bore
[0046] 6 melt feed
[0047] 7 melt inlet
[0048] 8 melt outlet
[0049] 9 filter medium
[0050] 10 outlet opening
[0051] 11 filter shell
[0052] 12 inner tube
[0053] 13 outer tube
[0054] 14 passages
[0055] 15 distribution line
[0056] 16 perforated plate
[0057] 17 carrier
[0058] 18 interior
[0059] 19 heating element
[0060] 20 heating box
[0061] 21 spin pump
[0062] 22 distribution channel
[0063] 23 melt lines
[0064] 24 cover
[0065] 25 openings
[0066] 26 screen wall
[0067] 27 shell
[0068] 28 end face
[0069] 29 intermediate plate
[0070] 30 melt channel
[0071] 31 collar
[0072] 32 bores
[0073] 33 annular chamber
* * * * *