U.S. patent application number 13/711276 was filed with the patent office on 2013-07-11 for method and apparatus for spinning and crimping a synthetic multifilament yarn.
This patent application is currently assigned to Oerlikon Textile GmbH & Co. KG. The applicant listed for this patent is Oerlikon Textile GmbH & Co. KG. Invention is credited to Diethard Huebner, Mathias Stuendl.
Application Number | 20130174531 13/711276 |
Document ID | / |
Family ID | 32694890 |
Filed Date | 2013-07-11 |
United States Patent
Application |
20130174531 |
Kind Code |
A1 |
Stuendl; Mathias ; et
al. |
July 11, 2013 |
METHOD AND APPARATUS FOR SPINNING AND CRIMPING A SYNTHETIC
MULTIFILAMENT YARN
Abstract
A method and an apparatus for spinning and crimping a synthetic
multifilament yarn, wherein a filament bundle is spun from a
polymer melt and compressed to a yarn plug. The yarn plug is
advanced at a cooling speed and cooled within a cooling zone in a
moving cooling groove. After cooling, the yarn plug is disentangled
to form a crimped yarn, with the latter being wound to a package.
The method of the invention also provides for selecting the length
of the cooling zone and the cooling speed of the yarn plug such
that the yarn plug is cooled in the cooling groove over a period of
at least 1 second. To this end, the apparatus of the invention
includes a cooling groove, whose width is dimensioned such that the
yarn plug can be advanced in meander form in a plurality of
superposed layers.
Inventors: |
Stuendl; Mathias; (Wedel,
DE) ; Huebner; Diethard; (Bordesholm, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Oerlikon Textile GmbH & Co. KG; |
Remscheid |
|
DE |
|
|
Assignee: |
Oerlikon Textile GmbH & Co.
KG
Remscheid
DE
|
Family ID: |
32694890 |
Appl. No.: |
13/711276 |
Filed: |
December 11, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11181161 |
Jul 14, 2005 |
8342834 |
|
|
13711276 |
|
|
|
|
PCT/EP2003/002345 |
Mar 7, 2003 |
|
|
|
11181161 |
|
|
|
|
Current U.S.
Class: |
57/281 |
Current CPC
Class: |
D02G 1/122 20130101;
D02G 1/12 20130101; D01H 7/00 20130101; D02J 13/005 20130101 |
Class at
Publication: |
57/281 |
International
Class: |
D01H 7/00 20060101
D01H007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 15, 2003 |
DE |
103 01 212.5 |
Claims
1. A method for spinning and crimping a synthetic multifilament
yarn, comprising the steps of spinning at least one filament bundle
from a polymeric melt and compressing the bundle to a yarn plug,
cooling the yarn plug by advancing the plug at a cooling speed
through a cooling zone which comprises a moving cooling groove,
disentangling the yarn plug after cooling to form a crimped yarn
which is wound to a package, and wherein the length of the cooling
zone and the cooling speed of the yarn plug are in proportion with
respect to each other and so that the yarn plug is cooled in the
cooling groove over a time period of at least one second.
2. The method of claim 1, wherein the yarn plug is cooled in the
cooling groove over a period of at least two seconds.
3. The method of claim 1, wherein before being cooled, the yarn
plug advances at a yarn advancing speed, and while being cooled at
the cooling speed, with the cooling speed being lower than the yarn
advancing speed.
4. The method of claim 3, wherein the yarn advancing speed of the
yarn plug is at least twice as high as the cooling speed of the
yarn plug.
5. The method of claim 1, wherein at the beginning of the cooling
zone the yarn plug is laid in the cooling groove in meander
form.
6. The method of claim 5, wherein the yarn plug advances in the
cooling groove on the circumference of a rotatably driven cooling
drum, with the bottom of the cooling groove forming an air
permeable cooling surface.
7. The method of claim 1, wherein the yarn plug is cooled within
the cooling zone by a cooling medium flow.
8. The method of claim 7, wherein the cooling medium flow is
generated by a source of vacuum and/or a source of overpressure.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application is a divisional application of U.S.
patent application Ser. No. 11/181,161, filed on Jul. 14, 2005,
which is a continuation of international application
PCT/EP2003/002345, filed 7 Mar., 2003, and which designates the
U.S. The disclosure of the referenced applications are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a method for spinning and crimping
a synthetic multifilament yarn, as well as an apparatus for
spinning and crimping a synthetic multifilament yarn.
[0003] In the production of a crimped yarn, a plurality of
strandlike filaments are extruded in a first step from a
thermoplastic melt by means of a spin unit. After cooling, the
filament bundle is combined and subsequently compressed to a yarn
plug by means of a crimping device. In this process, the filaments
of the filament bundle are deformed in the yarn plug to loops and
coils by means of a preferably heated fluid. To realize such a
deformation of the filaments, the crimping device includes a
stuffer box chamber, in which the conveying medium compresses the
filament bundle to the yarn plug. Thus, the desired loops and coils
of the individual filaments form, as the filaments impact upon the
yarn plug inside the stuffer box chamber.
[0004] To obtain as much as possible a stable crimp, it is
preferred to advance the yarn through a heated conveying medium and
to heat it at the same time, so that a plastic deformation is able
to occur in the individual filaments. To set the crimp, the yarn
plug advances through a cooling zone. The cooling zone is formed by
a cooling groove preferably on the circumference of a rotating
cooling drum. In this arrangement, the length of the cooling zone
is defined by the diameter of the cooling drum and by a partial
looping on the circumference of the cooling drum. During the
cooling, the cooling drum is driven for rotation, so that the
circumferential speed of the cooling groove equals the cooling
speed of the yarn plug, at which the yarn plug advances through the
cooling zone. A method and an apparatus of this type for spinning
and crimping a synthetic multifilament yarn are disclosed, for
example, in DE 196 13 177 A1.
[0005] According to DE 196 13 177 A1, a most effective and uniform
cooling of the yarn plug requires a defined duration of the
cooling. Thus, the art proposes to increase the dwelling time in
that the yarn plug advances with a partial looping over a second,
subsequent cooling drum. With that, however, it is not possible to
achieve an uninterrupted, uniform cooling of the yarn plug, since
the transition from the first cooling drum to the second cooling
drum represents each time an undefined interruption of the cooling
process.
[0006] U.S. Pat. No. 5,974,777 discloses a method and an apparatus
for cooling a yarn plug, wherein the yarn plug advances with
several loopings over the circumference of a cooling drum. While
this procedure permits achieving longer dwelling times for cooling
the yarn plug even at higher process speeds, it has the
disadvantage that the combined yarn plugs interfere with one
another on the circumference of the cooling drum, so that, for
example, individual filaments of adjacent plugs interlock and lead
to undesired filament breaks upon disentanglement of the plugs. In
addition, it is necessary to displace the yarn plugs on the cooling
drum surface, so that additional shearing forces act upon the plug.
Furthermore, such a displacement on the circumference of the
cooling drum may cause individual filaments to interlock on the
cooling surface.
[0007] It is therefore an object of the invention to further
develop a generic type of method and apparatus for spinning and
crimping a synthetic multifilament yarn such that after cooling the
yarn plug, it is ensured that a stable and high crimp of the yarn
is achieved irrespective of the production speed.
SUMMARY OF THE INVENTION
[0008] The invention is based on the discovery that the dwelling
time of the yarn plug within the cooling zone or in the cooling
groove is the decisive parameter for cooling the yarn plug. Known
as further parameters for cooling the yarn plug are the temperature
difference between the yarn plug and the cooling medium as well as
the volume flow of the cooling medium. However, the influence of
these parameters is small in proportion with the duration of the
cooling. For example, in tests with a textured yarn of a polyamide
PA6 it was possible to find that duplicating the time from 0.25
seconds to 0.5 seconds resulted in an improvement of the crimp of
about 10%. A further duplication of the cooling period from 0.5
seconds to 1 second allowed to achieve a further improvement of the
crimp of 4%. This asymptotic behavior between dwelling time and
crimp applies to all types of polymers. Thus, the length of the
cooling zone and the cooling speed of the yarn plug are decisive
parameters for the cooling period of the yarn plug. The method of
the invention is characterized in that the length of the cooling
zone and the cooling speed of the yarn plug are proportionate to
each other, so that the yarn plug is cooled in the cooling groove
over a period of at least one second. This ensures a substantially
complete cooling of the yarn plug, so as to permit attaining a high
degree of crimp in the yarn.
[0009] In making further use of the asymptotic behavior between the
duration of the cooling and the crimp of the textured yarn, the
length of the cooling zone and the cooling speed of the yarn plug
are preferably selected such that the yarn plug is cooled on the
circumference of the cooling drum over a period of at least two
seconds.
[0010] In this process, there basically exist two possibilities of
maintaining the ratio of the length of the cooling zone to the
cooling speed of the yarn plug, which is decisive for cooling the
yarn plug. Thus, a predetermined cooling speed permits varying the
length of the cooling zone, or a predetermined length of the
cooling zone permits changing the cooling speed of the yarn plug.
The cooling length is largely defined by the constructional
condition of the cooling groove that is provided for receiving the
yarn plug, and is often limited by an allowed space. However, to
maintain even in the case of relatively short cooling zones, the
decisive ratio of length of the cooling zone to cooling speed of
the yarn plug, it is preferred to use the variant of the method,
wherein the yarn plug advances before cooling at a yarn advancing
speed, and during the cooling at a cooling speed, with the cooling
speed being lower than the yarn advancing speed. Thus, more yarn
plug material advances to the cooling zone per unit time.
Consequently, the greater the difference is between the yarn
advancing speed and the cooling speed, the longer the period for
cooling the yarn plug.
[0011] With the use of the advantageous further development of the
method according to the invention, wherein at the beginning of the
cooling zone, the yarn plug is laid in the cooling groove in
meander form, preferably in a plurality of superposed layers, it is
possible to achieve a uniform filling of the groove and with that a
uniform cooling of the yarn plug.
[0012] Preferably, the yarn plug is cooled by a cooling medium flow
that penetrates the yarn plug. To this end, it is possible to
generate the cooling medium flow by a source of vacuum. To
intensify cooling, it also possible to use a source of overpressure
to generate an additional cooling medium flow, which is blown, for
example, as cooling air, onto the yarn plug.
[0013] The method of the invention is characterized by a clearly
increased crimp in the yarn. A carpet produced from such a yarn
exhibited a high cover ability without any streak or cloud
formation.
[0014] The method of the invention is suited for all polymer types,
such as, for example, PA and PP.
[0015] To be able to carry out the method of the invention, the
apparatus of the invention has been found particularly suitable,
and wherein the width of the cooling groove for receiving and
advancing the yarn plug is dimensioned such that the yarn plug is
allowed to advance in meander form in a plurality of superposed
layers. This allows to ensure an intensive cooling of the yarn plug
even at high process speeds, since the yarn advancing speed can be
adjusted substantially higher than the cooling speed of the yarn
plug.
[0016] To achieve a uniform filling of the cooling groove, a
spacing is adjusted between the outlet of the texturing device and
the cooling groove, with the width of the cooling groove being at
least twice as large as the diameter of the yarn plug.
[0017] Basically, the cooling groove can be provided on a belt-type
carrier, or according to an advantageous further development of the
invention, on the circumference of a cooling drum. This
construction permits controlling the cooling speed for advancing
the yarn plug in a simple manner by the drive of the cooling
drum.
[0018] Preferably, a source of vacuum is associated to the cooling
drum, which permits generating a cooling medium flow that
penetrates the yarn plug and the screen-type bottom of the cooling
groove.
[0019] For additionally cooling the yarn plug inside the cooling
groove, an additional blower with a source of overpressure may be
associated to the cooling drum, which permits generating an
additional cooling medium flow that is directed into the cooling
groove and onto the yarn plug.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In the following, the method of the invention is described
in greater detail by reference to preferred embodiments of the
apparatus according to the invention. In the drawing:
[0021] FIG. 1 is a schematic view of a first embodiment of the
apparatus according to the invention;
[0022] FIG. 2.1 is a schematic fragmentary side view of the
embodiment of FIG. 1;
[0023] FIG. 2.2 is a schematic end view of the crimping device and
the cooling device as shown in FIG. 2.1;
[0024] FIG. 3 is a schematic view of a diagram for illustrating the
interdependence of the cooling period of the yarn plug and the
crimp of the yarn; and
[0025] FIG. 4 is a schematic view of a further embodiment for
cooling the yarn plug.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] FIG. 1 schematically illustrates a first embodiment of an
apparatus according to the invention for carrying out the method of
the invention. The apparatus comprises a spin unit 1 that connects
via a melt supply line 3 to a melt producer, for example, a pump or
an extruder (not shown). The spin unit 1 contains a spin head 2
which mounts on its underside at least one spinneret 4. The
spinneret 4 includes a plurality of spin holes, through which a
polymer melt supplied to the spin head 2 is extruded under pressure
to a plurality of individual filaments 6. Downstream of the spin
unit 1, a cooling shaft 5 is provided, through which the filaments
6 advance, so that the filaments emerging at approximately the melt
temperature are cooled. To this end, the cooling shaft 5 could be
connected, for example, to a cross-flow quench system, which blows
a cooling air substantially crosswise to the filaments 6.
[0027] In the outlet region of the cooling shaft 5, a yarn guide
and a yarn lubrication device 8 extend. The yarn lubrication device
8 applies to the filaments 6 a lubricant, so that the filaments 6
combine to a filament bundle 10. A yarn feed godet unit 9
downstream of the cooling shaft 5 withdraws the filament bundle 10
from the spinneret 4, and advances it to a subsequent draw godet
unit 12. From the draw godet unit 12, the filament bundle 10 enters
a crimping device 7. In the crimping device 7, the previously drawn
filament bundle 10 is compressed to a yarn plug 13.
[0028] Arranged downstream of the crimping device 7 is a cooling
device 11 with a moving cooling groove 26. The cooling groove 26
serves to receive and cool the yarn plug 13. The construction and
operation of the cooling device 11 will be described in greater
detail in the following. To disentangle the yarn plug 13, a
withdrawal godet unit 14 withdraws the crimped yarn 15, and
advances it to a takeup unit 16. In the takeup unit 16, the crimped
yarn 15 is wound to a package 17.
[0029] The construction and arrangement of the individual units of
the embodiment shown in FIG. 1 are exemplary. For example, it is
possible to supplement, exchange, or replace the treatment devices
and guide elements. To produce a yarn cohesion of the filaments or
the crimped filaments, it is possible to arrange an entanglement
device 18 upstream and/or downstream of the crimping device.
[0030] The embodiment of the apparatus according to the invention
as shown in FIG. 1 is particularly suited for producing carpet
yarns. To this end, it is necessary that the crimped yarn have a
crimp that is adequate for final processing. Thus, the crimping
device 7 and the cooling device 11 downstream thereof represent an
important treatment step, which will be described in greater detail
in the following.
[0031] FIG. 2.1 illustrates a fragment of the embodiment of FIG. 1,
and is a schematic cross sectional view of the crimping device 7
and the subsequent cooling device 11. FIG. 2.2 is a schematic end
view of the units. Unless specific reference is made to one of the
Figures, the following description will apply to both Figures.
[0032] FIGS. 2.1 and 2.2 illustrate the crimping device 7 and the
cooling device 11 downstream of the crimping device 7 of the
embodiment of the apparatus according to the invention as shown in
FIG. 1. The crimping device 7 comprises a nozzle-shaped yarn feed
channel 20. The yarn feed channel 20 essentially consists of two
sections, which are separated from each other by a narrowest cross
section. In a first section, a short distance upstream of the
narrowest cross section, the nozzle holes of an injector 19 extend
into the yarn feed channel 20. The injector 19 connects to a source
of fluid (not shown). In the second section, downstream of the
narrowest cross section, the yarn feed channel 20 widens and ends
in a directly following stuffer box chamber 22.
[0033] In the inlet region of the stuffer box chamber 22, the wall
of the stuffer box chamber is made air permeable, and arranged
inside a pressure relief chamber 21. Downstream of the pressure
relief chamber 21, the stuffer box chamber 22 continues in the form
of a discharge channel 23 having a substantially unchanged cross
section. The end of the discharge channel 23 forms a plug outlet
24.
[0034] The cooling device 11 is constructed as a rotatable cooling
drum 25. The cooling drum 25 is driven at a circumferential speed
via a drive shaft 30 by a drive 31 (FIG. 2.2). To receive the yarn
plug 13 produced by the crimping device 7, the cooling drum 25
comprises a cooling groove 26 that extends over its circumference.
A bottom 27 of the cooling groove 26 is made air permeable, so that
a cooling medium flow that is preferably generated from the outside
inward, penetrates and cools the yarn plug 13 advancing in the
cooling groove 26. To this end, a pressure chamber 34 is formed in
the interior of the cooling drum 25, which connects via a suction
line 28 to a source of vacuum 29. With that, the ambient air
outside the cooling drum 26 is used as medium for cooling.
[0035] The cooling groove 26 formed on the circumference of the
cooling drum 25 has a width B. The width B of the cooling groove 26
is dimensioned in relation to the yarn plug 13 such that the width
B is preferably greater than twice the amount of the yarn plug
diameter D, i.e., B.sub.>2D.
[0036] Between the plug outlet 24 and the cooling groove 26, a free
spacing A extends to permit an unobstructed deposit of the yarn
plug 13 in the cooling groove 26. During the crimping process, the
spacing A remains unchanged.
[0037] In the crimping device 7, a heated conveying fluid enters
the yarn feed channel 20 via the injector 19. This causes a suction
effect to develop at the upper end of the yarn feed channel 20,
which sucks the filament bundle 10 into the crimping device 7. The
conveying fluid advances the filament bundle 10 through the yarn
feed channel 20 into the stuffer box chamber 22. In the stuffer box
chamber 22, the filament bundle 10 compacts to a yarn plug 13. In
so doing, the filament bundle 10 opens up, and the individual
filaments come to lie on top of one another in loops and coils. In
this process, the formation of the yarn plug 13 is largely defined
by the quality of the conveying fluid and by the pressure of the
conveying fluid. As conveying fluid it is preferred to use hot air.
To decrease the pressure of the conveying fluid, the upper region
of the stuffer box chamber 22 is made air permeable in the form of
air slots or lamellas, so that the conveying fluid is able to
escape into a pressure relief chamber 21 and from there to the
outside.
[0038] The yarn plug 13 advances at a defined, adjusted speed
v.sub.F through the stuffer box chamber 22 to the plug outlet 24.
From there, the yarn plug 13 enters the cooling groove 26 at the
yarn advancing speed v.sub.F. The cooling groove 26 moves at a
cooling speed v.sub.K, which is defined by the circumferential
speed of the cooling drum 25. The cooling speed v.sub.K is adjusted
substantially lower than the yarn advancing speed v.sub.F. As a
function of the ratio of the yarn advancing speed to the cooling
speed, the yarn plug 13 is deposited in the cooling groove 26 in
multiple layers and in meander form because of the unobstructed
advance. In this connection, the width B of the cooling groove 26
and the ratio of the yarn advancing speed to the cooling speed are
adapted to each other such that they allow the yarn plug 13 to fill
the cooling groove 26 uniformly.
[0039] The yarn plug 13 advances through the cooling zone on the
circumference of the cooling drum 25. The cooling zone is defined
by the degree of the looping of the yarn plug 13 on the cooling
drum 25. In the embodiment of FIG. 2.1, the yarn plug 13 loops the
cooling drum 25 at an angle of 180.degree.. Within the cooling
zone, the yarn plug 13 undergoes a cooling by the cooling medium
flow that is generated from the outside inward. After cooling, the
yarn plug 13 is disentangled at the end of the cooling zone to form
the crimped yarn 15.
[0040] The length of the cooling zone is determined by the diameter
of the cooling drum 25 and the degree of looping of the yarn plug
13 on the circumference of the cooling drum 25. Cooling drums 25
normally have a diameter from 0.3 to 0.6 m. In an example, a
cooling drum with a diameter of 400 mm was used. With a looping
angle of 180.degree., this resulted in a length of the cooling zone
of about 0.6 m. The yarn advancing speed v.sub.F was 90 m/min. The
cooling speed v.sub.K was adjusted to 20 m/min. This resulted in a
cooling time of about 1.8 seconds for cooling the yarn plug. With
that, it was ensured that the yarn plug underwent an intensive
cooling after advancing through the cooling zone, and that the yarn
15 thus exhibited a stable and high crimp.
[0041] In FIG. 3, a diagram illustrates the interdependence of time
for cooling the yarn plug and the crimp in the produced crimped
yarn. The illustrated slope of the curve makes it clear that in the
range of less than 1 sec. cooling time, a high dependence exists
between the cooling time and the crimp. As the cooling time
increases, the curve becomes flatter to approximate asymptotically
a limit value of the crimp. This relation between the cooling time
and the crimp of the crimped yarn basically applies to all polymer
types. In this respect, the method of the invention ensures that at
a minimum cooling time of 1 second, preferably 2 seconds, a high
degree of crimp is obtained in the produced yarn.
[0042] Tests with an additional cooling of the yarn plug by
unheated air further resulted in that the positive effect of
cooling with unheated air sets in only at longer dwelling times of
about 0.5 seconds. Thus, the method of the invention accomplishes a
maximum of crimp stability and crimp irrespective of the way of
cooling the yarn plug.
[0043] Preferably, a uniform filling of the cooling groove 26 on
the circumference of the cooling drum 25 is achieved. The
multilayer deposit of the yarn plug in meander form is adjusted
such that no significant gaps form within the cooling groove 26.
This results in a uniform flow resistance and thus in a uniform
cooling of the yarn plug. The deposit of the yarn plug can be
influenced by additional guide elements. However, the random
orientation of the yarn plug in the cooling groove can also be
realized in a simple manner by adjusting the spacing A (FIG. 2.1)
between the yarn plug outlet and the cooling groove, as well as by
the selection of the width B of the cooling groove. The ratio of
the yarn advancing speed v.sub.F, at which the yarn plug advances
before being cooled, to the cooling speed v.sub.K, at which the
yarn plug advances while being cooled, is in a range from
v.sub.F/v.sub.K=0.1 to 0.4. With that, it is possible to realize
even high production speeds of more than 3,000 m/min. (crimping
speed) and a long dwelling time.
[0044] FIG. 4 schematically illustrates a modification of the
cooling device of the embodiment of FIG. 1. In this modification, a
blower 32 is arranged in spaced relationship with the cooling drum
25 in the region of the cooling groove 26, and connected to a
source of overpressure 33. The blower 32 has an elongate shape that
overlaps at least one section of the cooling zone. A cooling medium
flow is generated by the source of overpressure 33 through a
plurality of air outlets, and directed to the yarn plug 13 in the
cooling groove 26.
[0045] The construction of both the crimping device 7 and the
cooling device 11 is identical with the foregoing embodiment, so
that the foregoing description may herewith be incorporated by
reference.
[0046] Many modifications and other embodiments of the invention
set forth herein will come to mind to one skilled in the art to
which the invention pertains having the benefit of the teachings
presented in the foregoing description and the associated drawings.
Therefore, it is to be understood that the invention is not to be
limited to the specific embodiments disclosed and that
modifications and other embodiments are intended to be included
within the scope of the appended claims. Although specific terms
are employed herein, they are used in a generic and descriptive
sense only and not for purposes of limitation.
* * * * *