U.S. patent application number 10/877187 was filed with the patent office on 2005-01-20 for device for the production of cellulose staple fibers.
Invention is credited to Feilmair, Wilhelm, Firgo, Heinrich, Nussbaumer, Franz, Rohrer, Christian, Schrempf, Christoph, Schwab, Helmut.
Application Number | 20050012238 10/877187 |
Document ID | / |
Family ID | 3689709 |
Filed Date | 2005-01-20 |
United States Patent
Application |
20050012238 |
Kind Code |
A1 |
Schrempf, Christoph ; et
al. |
January 20, 2005 |
Device for the production of cellulose staple fibers
Abstract
The invention is concerned with a device for the production of
cellulosic staple fibers comprising a cutting device (1) for
cutting cellulosic continuous filaments into staple fibers, a
liquid-transport device (2) for transporting the staple fibers. The
device according to the invention is characterized in that the
liquid-transport device (2) is provided with a portion (4) shaped
as a syphon (4).
Inventors: |
Schrempf, Christoph; (Bad
Schallerbach, AT) ; Feilmair, Wilhelm; (Seewalchen,
AT) ; Nussbaumer, Franz; (Vocklamarkt, AT) ;
Schwab, Helmut; (Schwanenstadt, AT) ; Rohrer,
Christian; (Linz, AT) ; Firgo, Heinrich;
(Vocklabruck, AT) |
Correspondence
Address: |
BAKER & BOTTS
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
|
Family ID: |
3689709 |
Appl. No.: |
10/877187 |
Filed: |
June 24, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10877187 |
Jun 24, 2004 |
|
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|
PCT/AT02/00363 |
Dec 19, 2002 |
|
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Current U.S.
Class: |
264/188 |
Current CPC
Class: |
D01G 1/04 20130101 |
Class at
Publication: |
264/188 |
International
Class: |
D01F 002/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 27, 2001 |
AT |
A2042/2001 |
Claims
1-19. (Cancelled)
20. A device for the production of cellulosic staple fibers
comprising a cutting device for cutting cellulosic continuous
filaments into staple fibers, and a liquid transport device
comprising a syphon for transporting the staple fibers.
21. The device according to claim 20, further comprising a
suspension means for suspending the staple fibers to form a
fleece.
22. The device according to claim 20, wherein the outlet of the
cutting device is connected to the suspension means by way of the
liquid transport device.
23. The device according to claim 21, wherein the outlet of the
cutting device is connected to the suspension means by way of the
liquid transport device.
24. The device according to claim 22, wherein the syphon is
immediately adjacent to the cutting device.
25. The device according to claim 20, wherein the syphon comprises
a downward limb and an upward limb connected by a horizontal
intermediate portion.
26. The device according to claim 25, wherein the horizontal
intermediate portion of the syphon has a length that is equal to or
greater than the length of the downward limb of the syphon.
27. The device according to claim 26, wherein the length of the
horizontal intermediate portion of the syphon is at least ten times
longer than the length of the downward limb of the syphon.
28. The device according to claim 26, wherein the length of the
horizontal intermediate portion of the syphon is at least thirty
times longer than the length of the downward limb of the
syphon.
29. The device according to claim 25, wherein the downward limb and
the upward limb of the syphon have lengths that are essentially
equal.
30. The device according to claim 21, wherein the liquid transport
device further comprises a portion configured as a tube leading
from the syphon to the suspension means.
31. The device according to claim 30, wherein the tube portion
comprises a downward partial section.
32. The device according to claim 31, wherein the downward partial
section of the tube portion leads downward in an essentially
vertical manner.
33. The device according to claim 31, wherein the syphon comprises
a downward limb and an upward limb connected by a horizontal
intermediate portion and the vertical dimension of the downward
partial section of the tube portion is essentially equal to a
vertical dimension of a limb of the syphon.
34. The device according to claim 31, wherein the downward partial
section changes into a further partial section leading to the
suspension means.
35. The device according to claim 34, wherein the further partial
section runs essentially horizontally.
36. The device according to claim 34, which further comprises a
downward bulge provided at a transitional point between the
downward partial section and the further partial section.
37. A process for producing cellulosic staple fibers, comprising
the steps of (i) cutting freshly spun cellulosic filaments in a
cutting device to produce staple fibers, (ii) transporting the
staple fibers from an outlet of the cutting machine to a suspension
means by a liquid transport device comprising a syphon and (iii)
suspending the transported staple fibers to form a fleece in the
suspension means.
38. The process according to claim 37, wherein the cellulosic
staple fibers are retained in the liquid transport device for a
period of from two to forty seconds.
39. The process according to claim 38, wherein the cellulosic
staple fibers are retained in the liquid transport device for a
period of from ten to thirty seconds.
40. The process according to claim 37, wherein the staple fibers in
the syphon have a flow rate of 0.15 to 2.0 m/s.
41. The process according to claim 40, wherein the staple fibers in
the syphon have a flow rate of 0.3 to 1.5 m/s.
42. The process according to claim 37, wherein the liquid transport
device comprises a portion configured as a tube leading from the
syphon to the suspension means, said tube portion comprising a
downward partial section and the fibers in the downward partial
section are accelerated to a speed of 1 to 5 m/s.
43. The process according to claim 42, wherein the fibers in the
downward partial section are accelerated to a speed of 2 to 3
m/s.
44. The process according to claim 37, wherein the cellulosic
staple fibers are solvent-spun.
45. The process according to claim 37, wherein the outlet of the
cutting device is connected to the suspension means by way of the
liquid transport device.
46. The process according to claim 45, wherein the syphon is
immediately adjacent to the cutting device.
47. The process according to claim 37, wherein the syphon comprises
a downward limb and an upward limb connected by a horizontal
intermediate portion.
48. The process according to claim 47, wherein the horizontal
intermediate portion of the syphon has a length that is equal to or
greater than the length of the downward limb of the syphon.
49. The process according to claim 48, wherein the length of the
horizontal intermediate portion of the syphon is at least ten times
longer than the length of the downward limb of the syphon.
50. The process according to claim 48, wherein the length of the
horizontal intermediate portion of the syphon is at least thirty
times longer than the length of the downward limb of the
syphon.
51. The process according to claim 47, wherein the downward limb
and the upward limb of the syphon have lengths that are essentially
equal.
52. The process according to claim 37, wherein the liquid transport
device further comprises a portion configured as a tube leading
from the syphon to the suspension means.
53. The process according to claim 52, wherein the tube portion
comprises a downward partial section.
54. The process according to claim 53, wherein the downward partial
section of the tube portion leads downward in an essentially
vertical manner.
55. The process according to claim 53, wherein the syphon comprises
a downward limb and an upward limb connected by a horizontal
intermediate portion and the vertical dimension of the downward
partial section of the tube portion is essentially equal to the
vertical dimension of a limb of the syphon.
56. The process according to claim 53, wherein the downward partial
section changes into a further partial section leading to the
suspension means.
57. The process according to claim 56, wherein the further partial
section runs essentially horizontally.
58. The process according to claim 56, wherein the tube portion
further comprises a downward bulge provided at a transitional point
between the downward partial section and the further partial
section.
59. The process according to claim 53, wherein the staple fibers in
the downward partial section of the tube portion are accelerated to
a speed of from 1 to 5 m/s.
60. The process according to claim 59, wherein the staple fibers
are accelerated to a speed of from 2 to 3 m/s.
Description
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] The present application is a continuation of International
Patent Application No. PCT/AT02/00363, filed Dec. 19, 2002,
published in German on Jul. 10, 2003 as International Patent
Publication No. W003/056079A1, which claims priority to Austrian
Application No. A 2042/2001, filed Dec. 27, 2001, each of which are
incorporated herein in their entireties.
BACKGROUND OF THE INVENTION
[0002] The present invention is concerned with a device as well as
a process for the production of cellulosic staple fibers.
[0003] In conventional processes for the production of cellulosic
staple fibers, freshly spun, cellulosic continuous filaments are
cut into staple fibers in a cutting machine. From the outlet of the
cutting machine, the staple fibers are transported along and
treated further. For instance, the staple fibers are suspended to a
fleece in a suspension means. Thereafter, said fleece is subjected
to further treatment steps such as washing and finishing
stages.
[0004] Devices known from the state of the art comprise a cutting
device for cutting the continuous filaments into staple fibers and
a liquid-transport device for transporting the staple fibers.
[0005] According to the state of the art, the liquid-transport
device usually is configured as a groove the beginning of which is
arranged, for instance, underneath the cutting device. A bundle of
continuous filaments to be cut enters the cutting device and is cut
there into fibers of a particular length usually by means of
rotating knives. After cutting, the cut fibers form a bundle or
staple, respectively. The cut fibers are flushed from the cutting
device into the groove by means of a liquid such as water and are
transported along in the groove by means of the liquid, for
instance, towards a suspension means.
[0006] In those known processes or devices, respectively, the
problem arises that the staples formed during cutting fail to come
apart into individual fibers by the time the fiber fleece is formed
in the suspension means. Staples which have not sufficiently come
apart into individual fibers are referred to herein as "aggregated"
(or "agglomerated") staples.
[0007] Such aggregated staples in the fiber fleece cause
in-homogeneities with respect to the wash-out and exchange behavior
in the stages of after treating the fleece. Usually, the staples
are washed out worse, bleached less, cross-linked worse, finished
worse etc.
[0008] Furthermore, aggregated staples often cause quality problems
during the subsequent treatment and processing of the fibers.
SUMMARY OF THE INVENTION
[0009] The present invention relates to a device for the production
of cellulosic staple fibers comprising a cutting device for cutting
cellulosic continuous filaments into staple fibers and a
liquid-transport device for transporting the staple fibers, where
the liquid-transport device comprises a syphon.
[0010] The object of the present invention is to provide a device
as well as a process by means of which the above mentioned
drawbacks are avoided and especially the number of aggregated
staples and their sizes (i.e. the number of fibers per staple) in
the fiber fleece is reduced.
[0011] That object is achieved by the aid of a device which
comprises a cutting device for cutting cellulosic continuous
filaments into staple fibers and a liquid-transport device for
transporting the staple fibers and which is characterized in that
the liquid-transport device is provided with a portion shaped as a
syphon.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows a schematic of the basic structure of a
cellulosic staple fiber production device in the prior art.
[0013] FIG. 2 shows a schematic of the basic structure of the
cellulosic staple fiber production device of the present
invention.
[0014] FIG. 3 shows a schematic of an embodiment of the cellulosic
staple fiber production device of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0015] It was found that, surprisingly, replacing the groove known
from the state of the art with a syphon facilitated the coming
apart of the fibers during the transport.
[0016] The syphon is filled to capacity by the liquid emerging from
the cutting device together with the fibers. Because of that, the
transport of the fiber staples is no longer effected in a streaming
but in a freely floating manner. The tendency to agglomerate
occurring in the known streaming process and the tumbling staple
movement is avoided.
[0017] Furthermore, the staples are able to swell freely since they
are wetted with liquid from all sides.
[0018] Preferably, the device according to the invention
furthermore comprises a suspension means for suspending the staple
fibers to a fleece. The liquid-transport device preferably leads
from the outlet of the cutting device to the suspension means.
[0019] Preferably, the syphon is immediately adjacent to the
cutting device.
[0020] In a further preferred embodiment of the device according to
the invention, an intermediate portion preferably running
essentially horizontally is provided between the downward and
upward limbs of the syphon.
[0021] The length of said intermediate portion is at least equal
to, preferably at least 10 times as long as, particularly
preferably at least 30 times as long as, the length of the downward
limb of the syphon.
[0022] In the intermediate portion, which preferably is a few times
as long as the length of the downward limb of the syphon, the flow
of the staples in the tube may develop further and the staples are
opened up even better.
[0023] The lengths of the two limbs of the syphon may essentially
be equal.
[0024] In a further preferred embodiment it is provided that the
liquid-transport device has a further portion preferably also
configured as a tube and leading from the syphon to the suspension
means.
[0025] Said further portion preferably comprises a downward partial
section, which, furthermore, preferably leads downward in an
essentially vertical way. The vertical dimension of the downward
partial section advantageously is essentially equal to the vertical
dimension of one of the limbs of the syphon.
[0026] By providing a downward partial section, the potential
energy of the fiber staples may be utilized even better at the
outlet of the syphon-type portion. During the downward movement,
the fiber staples are accelerated. To this end, it has proven to be
beneficial if an aperture for airing the tube is provided at a high
point of the syphon.
[0027] Preferably, the downward partial section changes into a
further partial section leading to the suspension means, which
further partial section preferably runs essentially
horizontally.
[0028] With the accelerated fiber staples impinging in the passage
leading from the downward partial section to the further partial
section, a further opening of the staples occurs.
[0029] To this end, preferably a downward bulge may be provided at
the transitional point between the downward partial section and the
further partial section, by means of which bulge the effect of that
impact is increased even further.
[0030] According to a further aspect, the object of the present
invention is achieved by means of a process wherein freshly spun,
cellulosic filaments are cut into staple fibers in a cutting
machine, the staple fibers are transported from the outlet of the
cutting machine to a suspension means and are suspended to a fleece
in the suspension means and the fleece is subjected to further
treatment steps, which process is characterized in that the
transport of the fibers from the outlet of the cutting machine to
the suspension means is carried out in a device according to the
invention.
[0031] In doing so, the retention time of the fibers in the
liquid-transport device preferably amounts to from 2 to 40 s.
preferably from 10 to 30 s. The flow rate of the fibers in the
portion shaped in the manner of a syphon preferably amounts to from
0.15 to 2 m/s, preferably from 0.3 to 1.5 m/s.
[0032] In a preferred embodiment of the process according to the
invention, which is realized using a device provided with a
downward partial section, the fibers in the downward partial
section preferably are accelerated to a speed of from 1 to 5 m/s,
preferably from 2 to 3 m/s.
[0033] The device according to the invention as well as the process
according to the invention are particularly suitable for the
production of solvent-spun, cellulosic staple fibers. Those fibers
are also known under the generic name "Lyocell fibers" and are
produced from a solution of cellulose in a tertiary amine oxide
(amine-oxide process).
[0034] In the following, preferred embodiments of the present
invention are explained in more detail by way of the figures as
well as the examples:
[0035] Thereby, FIG. 1 schematically shows the basic structure of
the device according to the genus. FIG. 2 schematically shows a
preferred embodiment of the device according to the invention. FIG.
3 shows a detail of a preferred embodiment with respect to the
downward partial section.
[0036] FIG. 1 shows a cutting device 1, a liquid-transport device 2
and a suspension means 3. By means of a liquid, the fibers cut into
staple fibers in the cutting device 1 are flushed into the
liquid-transport device 2, which, in the state of the art, is
configured as a groove not completely liquid-filled, and are
transported therein towards the suspension means 3. In the
suspension means 3, a fiber fleece is formed, which is washed and
after treated in further stages (not shown).
[0037] According to a preferred embodiment of the device according
to the invention, the liquid transport device 2, as seen in FIG. 2,
is provided with a portion 4 which, as a tube shaped as a syphon,
is configured with two limbs 5,6. Between the two limbs of
essentially equal lengths, an intermediate portion 7 running
essentially horizontally is provided, the length of which amounts
to a few times the length of the downward limb 5.
[0038] At the outlet of the syphon 4, a further portion 8 leading
to the suspension means 3 is provided. The portion 8 is provided
with a partial section 9 leading downward in an essentially
vertical way and changing into a further partial section 10 running
essentially horizontally and advantageously being tubular as well.
The vertical dimension of the partial section 9 is essentially
equal to the vertical dimensions of the two limbs 5,6 of the syphon
4. Optionally, however, the partial section 10 might also be open,
i.e., shaped as a groove, for instance.
[0039] In the preferred embodiment shown in FIG. 3, a downward
bulge 11 is provided at the transitional point between the downward
partial section 9 and the further partial section 10.
[0040] In the embodiment shown in FIGS. 2 and 3, furthermore, a
partial section 12 running essentially horizontally is provided
between the outlet of the syphon 4 and the partial section 9. At
the transitional point between the partial section 12 and the
partial section 9, air holes (not shown) may be arranged at the top
surface of the tube.
[0041] The functioning of the device according to FIGS. 2 and 3 is
as follows:
[0042] The staple fibers cut in the cutting device 1 are flushed by
means of a liquid from the cutting device 1 into the portion 4 of
the liquid-transport device 2, said portion being shaped as a tube,
and are transported along from there. Due to the syphon-type
configuration of the portion 4, the tube is completely
liquid-filled up to the outlet of the syphon. Thus, the fibers are
transported in the floating state and are completely surrounded by
liquid, whereby the staples are enabled to swell freely and better
opening (coming apart to release individual fibers) will occur.
[0043] After leaving the syphon 4, the fibers fall down in the
downward partial section 9 and hence are accelerated. With the
impact on the transitional point between partial section 9 and
partial section 10, a further opening of the staples occurs. That
effect may even be increased by means of the bulge 11 shown in FIG.
3. Thereafter, the fibers are transported in partial section 10 to
the suspension means 3, where a fleece is formed in a manner known
per se. In partial section 10, the tube is liquid-filled by about
50%, for instance.
EXAMPLE
[0044] In a continuously operating pilot plant for the production
of solvent-spun, cellulosic staple fibers, the fibers were cut and
transported in a device according to FIG. 3.
[0045] Thereby, the length of the limbs 5,6 of the syphon-type
portion 4 amounted to 0.5 m, the length of the intermediate portion
7 amounted to 10 m. The flow rate of the fibers in the syphon-type
portion 4 amounted to about 0.45 m/s. In the downward partial
section 9, the fibers were accelerated to a speed of about 2.5 mis.
The entire retention time of the fibers in the liquid-transport
device 2 amounted to about 20 s.
[0046] In order to assess the effect of the device, samples of the
fleece formed in the suspension means are taken. The number of
aggregated staples per 50 cm.sup.2 of fleece cross-section is
determined. Furthermore, the staples are grouped according to their
size ranges. The number of aggregated staples encountered according
to the respective size ranges is multiplied by a conversion factor
as follows: size range conversion factor
1 size range conversion factor >20 mm .times.20 20-10 mm
.times.10 10-5 mm .times.5 5-3 mm .times.3
[0047] (Staples of a size of less than 3 mm are not included in the
calculation.)
[0048] The values thus obtained are summed up. From this
calculation, a characteristic staple number results, which supplies
information about the quality of the formed fleece with respect to
the aggregated staples contained therein.
[0049] The characteristic staple number of the fleece made up of
fibers transported by means of the device according to the
invention amounted to 39. In contrast to that, the characteristic
staple number of a fleece made up of fibers produced in the same
way but transported in accordance with the state of the art
amounted to 67.
* * * * *