U.S. patent application number 13/699668 was filed with the patent office on 2013-06-06 for nozzle plate.
This patent application is currently assigned to BAYER INNOVATION GMBH. The applicant listed for this patent is Karl-Robert Boos, Arne Braun, Maren Heinemann, Thomas Konig, Lars Lachmann. Invention is credited to Karl-Robert Boos, Arne Braun, Maren Heinemann, Thomas Konig, Lars Lachmann.
Application Number | 20130140725 13/699668 |
Document ID | / |
Family ID | 44532760 |
Filed Date | 2013-06-06 |
United States Patent
Application |
20130140725 |
Kind Code |
A1 |
Heinemann; Maren ; et
al. |
June 6, 2013 |
NOZZLE PLATE
Abstract
The present invention provides a nozzle plate and the use of the
nozzle plate for producing filaments, preferably silica gel
fibers.
Inventors: |
Heinemann; Maren; (Bergisch
Gladbach, DE) ; Braun; Arne; (Leverkusen, DE)
; Konig; Thomas; (Leverkusen, DE) ; Boos;
Karl-Robert; (Burscheid, DE) ; Lachmann; Lars;
(Berlin, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Heinemann; Maren
Braun; Arne
Konig; Thomas
Boos; Karl-Robert
Lachmann; Lars |
Bergisch Gladbach
Leverkusen
Leverkusen
Burscheid
Berlin |
|
DE
DE
DE
DE
DE |
|
|
Assignee: |
BAYER INNOVATION GMBH
Leverkusen
DE
|
Family ID: |
44532760 |
Appl. No.: |
13/699668 |
Filed: |
May 24, 2011 |
PCT Filed: |
May 24, 2011 |
PCT NO: |
PCT/EP2011/058504 |
371 Date: |
February 15, 2013 |
Current U.S.
Class: |
264/13 ;
425/464 |
Current CPC
Class: |
B29C 48/345 20190201;
D01D 4/027 20130101; C03B 37/011 20130101; D01F 9/08 20130101; C03B
37/083 20130101; B29C 48/05 20190201; D01D 4/02 20130101; C01B
33/14 20130101; C01B 33/157 20130101; B29C 48/022 20190201; D01D
5/06 20130101; B29K 2083/00 20130101 |
Class at
Publication: |
264/13 ;
425/464 |
International
Class: |
B29C 47/30 20060101
B29C047/30 |
Foreign Application Data
Date |
Code |
Application Number |
May 26, 2010 |
DE |
102010021636.4 |
Claims
1. A nozzle plate comprising at least one nozzle with a nozzle
opening, wherein the nozzle opening has a cross-sectional area of
size A1, wherein a tear-off edge with an angle .beta. in a range
from 5.degree. to 90.degree. extends around the nozzle opening,
wherein an area which immediately adjoins the nozzle opening
outside the nozzle and extends around the nozzle opening has an
area of the size A2, and wherein a ratio A2/A1 is not more than
20.
2. The nozzle plate as claimed in claim 1, wherein the ratio A2/A1
is not more than 15, optionally not more than 10.
3. The nozzle plate as claimed in claim 1, wherein the angle .beta.
of the tear-off edge is in a range from 10.degree. to 90.degree.,
optionally in a range from 20.degree. to 90.degree..
4. The nozzle plate as claimed in claim 1, wherein the nozzle plate
has a number of nozzles in a range from 1 to 1000.
5. The nozzle plate as claimed in claim 4, wherein each nozzle
comprises a channel which is initially cylindrical, then tapers
conically in a flow direction down to a cross-sectional area of
size A1 and again extends cylindrically to the nozzle opening,
wherein a cylinder adjoining the nozzle opening has a length L and
a diameter D, and wherein the following applies to a ratio L/D:
0.5.ltoreq.L/D.ltoreq.10.
6. The nozzle plate as claimed in claim 5, wherein the ratio L/D is
in a range 1 to 5, optionally in a range from 1.5 to 3.
7. The nozzle plate as claimed in claim 4, wherein each nozzle take
a form of a nozzle insert which is inserted into a corresponding
opening in the nozzle plate.
8. A nozzle plate as claimed in claim 1 for capable of producing a
filament, which optionally comprises silica gel fibers.
9. A method of producing a filament comprising using a nozzle plate
as claimed in claim 1.
10. A method of claim 9, wherein said filament comprises a silica
gel fiber.
Description
[0001] The present invention provides a nozzle plate and use of the
nozzle plate for producing continuous filaments, preferably silica
gel fibers.
[0002] Patent DE19609551C1 and published patent application
DE102004063599A1 disclose a method for producing silica gel fibers.
The method comprises a plurality of steps. In a first step, a
spinning composition is produced which, in a second step, is
pressed from a pressure vessel through nozzles, where it emerges in
the form of filaments. Depending on the size of the nozzles, the
filaments have a diameter of approx. 10 to 100 .mu.m.
[0003] Published patent application DE102004063599A1 discloses
details regarding the nozzles through which the spinning
composition is pressed. A 7- or 19-hole nozzle plate is used. The
drill bore leading up to a hole is 3.0 mm wide and the hole
diameter D amounts to 0.15 mm. At a capillary length L of 0.45 mm,
an L/D ratio of 3 is obtained. FIG. 2 of the published patent
application shows a schematic diagram of the nozzle plate and an
individual hole-type nozzle in cross-section.
[0004] This nozzle plate described in the prior art exhibits
disadvantages. At the start of a pressing operation of the spinning
composition through a nozzle as disclosed in DE102004063599A1, the
emerging spinning composition wets the planar zone around the
nozzle orifice. Spinning composition collects around the orifice
until, under the effect of gravity, it gradually becomes detached
from the nozzle orifice and falls to the ground in the form of a
drop which takes a spun filament with it.
[0005] The individual nozzles here exhibit a different behavior
over time. There are individual nozzles from which a filament
immediately emerges, the thickness of which is, however, initially
nonuniform, since some of the emerging spinning composition sticks
behind on the region around the nozzle orifice and, apart from a
thin film, only becomes detached from the nozzle plate after
varying lengths of time. There are individual nozzles for which the
filament breaks off and only forms a new uniform filament once a
certain amount of time has elapsed. In addition to the
nonuniformity, the spinning composition located in the region
around the nozzle orifice may impair filament formation during the
entire spinning procedure if said spinning composition only becomes
very incompletely detached from the nozzle plate and the
composition which is left behind comes into contact with the
filament. This may give rise to disruption of filament formation
and movement which may go as far as a plurality of filaments
becoming tangled or the periodic formation of drops.
[0006] These problems result, for example, in its being necessary
to discard the filaments which initially emerge from the nozzles
due to their nonuniformity. If the method for producing filaments
is interrupted, uniform filaments can only be produced again after
a significant startup time and elaborate cleaning of the nozzle
plate. It is here very often observed that spun material, which
inevitably remains behind as a thin film around the nozzle opening
after detachment of the spinning composition from the nozzle plate,
leads to spinning composition only becoming very incompletely
detached from the nozzle plate when the spinning operation is
restarted, such that the nozzle plate must first be cleaned before
it can be used again.
[0007] On the basis of the described prior art, a person skilled in
the art is therefore faced with the problem of finding a solution
to the adhesion of spinning composition at the nozzle orifices and
the concomitant initial formation of nonuniform filaments. The
solution is in particular intended to be suitable for the
production of silica gel fibers.
[0008] According to the invention, said problem is solved by a
nozzle plate as claimed in claim 1. Preferred embodiments are
stated in the dependent claims.
[0009] The present invention accordingly provides a nozzle plate
comprising at least one nozzle with a nozzle opening, wherein the
nozzle opening has a cross-sectional area of size A1, wherein a
tear-off edge with an angle .beta. in the range from 5.degree. to
90.degree. extends around the nozzle opening, wherein the area
which immediately adjoins the nozzle opening outside the nozzle and
extends around the nozzle opening has an area of size A2,
characterized in that the ratio A2/A1 is less than 20.
[0010] A composition is pressed outwards out of the nozzle through
the nozzle opening. The size of the nozzle opening determines the
thickness of the strand emerging outwards out of the nozzle. The
nozzle opening has a cross-sectional area of size A1.
[0011] The spinning composition may be pressed through the spinning
nozzle in various ways. In the prior art, a pressure vessel, which
is pressurized with gas, is conventionally used. It is likewise
possible to press the spinning composition through the nozzle plate
with a suitable pump. Depending on the field of application, a
plurality of pumps are suitable for this purpose, such as for
example piston pumps, gear pumps, eccentric pumps and screw pumps.
Gear pumps are preferably used. It is likewise possible to press
the spinning composition through the nozzles from a cylindrical
container by means of a piston.
[0012] The spinning composition emerging outwards through a nozzle
opening should wet the region around the nozzle opening as little
as possible, since an uncontrollable accumulation of material
otherwise occurs around the nozzle opening. In particular at the
start, this accumulation results in nonuniform filament
formation.
[0013] A tear-off edge is therefore located around the nozzle
opening and the area outside the nozzle opening which extends
around the nozzle opening is kept as small as possible.
[0014] A tear-off edge with a minimum area of the orifice region
may in principle be achieved in that the nozzle takes the form of a
channel which extends perpendicularly through the tip of a straight
cone (see for example FIG. 3(a)). However, since for manufacturing
reasons there is always a ring with a finite width around such an
opening, the ratio A2/A1 cannot be minimized at will. This is
illustrated by FIGS. 3(b) and 5. The lower part of FIG. 3(b) shows
a nozzle in cross-section, in which a ring with a finite width
extends around the nozzle opening. FIG. 5 shows a plan view from
below of the same nozzle. The nozzle opening has a cross-sectional
area of size A1 while the ring has an area of size A2. According to
the invention, the ratio A2/A1 is less than 20.
[0015] The ratio A2/A1 is preferably less than 15, particularly
preferably less than 10, very particularly preferably less than 5
and most preferably less than 1.
[0016] The angle .beta. of the tear-off edge is preferably in the
range from 10.degree. to 90.degree., particularly preferably in the
range from 20.degree. to 90.degree., very particularly preferably
in the range from 30.degree. to 90.degree..
[0017] The nozzle plate according to the invention preferably
comprises a plurality of identical nozzles with the above-described
features. The number of nozzles is for example in the range from 1
to 1000, more preferably from 4 to 100.
[0018] The nozzles may be produced by drilling and/or milling
operations in the nozzle plate. The nozzle plate is preferably of
modular construction. This means that the nozzle plate has openings
into which nozzle inserts may be inserted. It is for example
conceivable to shrink-fit or screw the nozzle inserts into the
nozzle plate.
[0019] The nozzle plate according to the invention is suitable for
producing filaments, in particular silica gel fibers, in particular
in a dry spinning process as is disclosed by way of example in
DE19609551C1 and DE102004063599A1. The present invention
accordingly also provides the use of the nozzle plate according to
the invention for producing silica gel fibers.
[0020] Preferred embodiments of the nozzle plate according to the
invention are described in greater detail below, but without
limiting the invention to these examples. The nozzle openings shown
have a round cross-section. A round cross-section is always
preferred, but it is however also conceivable to make the
cross-section in any other conceivable shape, in particular oval.
It is likewise conceivable to combine features of individual
illustrated embodiments to create further embodiments according to
the invention which are not shown.
[0021] FIG. 1 is a schematic diagram of a preferred embodiment of a
nozzle plate according to the invention in plan view. The nozzle
plate is round and has 19 nozzles.
[0022] FIG. 2 is a schematic diagram of the nozzle plate from FIG.
1 in cross-section along the dashed line. The individual nozzles in
each case comprise a channel which tapers conically downwards.
[0023] FIGS. 3(a) to (e) are schematic diagrams of various
embodiments of nozzles. In FIG. 1(a), the nozzle opening is formed
by a channel which extends through the tip of a straight cone. In
this way, a sharp tear-off edge is formed around the nozzle
opening. The angle .beta. between the conically tapering cone
envelope and the vertical through the nozzle opening is in the
range from 10.degree. to 80.degree., preferably in the range from
20.degree. to 70.degree. and particularly preferably in the range
from 30.degree. to 60.degree..
[0024] In FIG. 3(b), the angle .beta. of the tear-off edge is
90.degree.. Around the nozzle opening there is a ring which is of
the smallest possible width so that the least possible wetting
occurs.
[0025] In the nozzles of FIGS. 3(c) to 3(e), the cylindrical region
of the nozzle channel has been lengthened in comparison with the
embodiments of FIGS. 3(a) and 3(b). This results in a larger L/D
ratio. The L/D ratio of the cylindrical region is in the range from
0.5 to 10, preferably in the range from 1 to 5, particularly
preferably in the range from 1.5 to 3.
[0026] In FIGS. 3(b), (d) and (e), the areas A1 and A2 extend
parallel to one another. It is, however, also conceivable for the
area A2 to extend at an angle to area A1. This is shown by way of
example in FIG. 4(a). The angle .omega. is preferably in the range
from 0.degree. to 80.degree., particularly preferably in the range
from 0.degree. to 60.degree..
[0027] It is also conceivable for the area A2 to be curved, as
shown by way of example in FIG. 4(b). It is, however, important for
there to be an edge extending around the nozzle opening which acts
as a tear-off edge for the filaments emerging from the nozzle
opening. As illustrated by the example of the embodiment of FIG.
3(a), this edge is characterized by the angle .beta..
[0028] If the angle .beta. amounts to 90.degree., the areas A1 and
A2 extend parallel to one another and wetting of the area A2 is
minimized according to the invention in that the ratio A2/A1 is
less than 20, preferably less than 15, particularly preferably less
than 10, very particularly preferably less than 5 and most
preferably less than 1.
[0029] FIG. 5 is a schematic diagram of a nozzle according to FIGS.
3(b), 3(d), 3(e), 4(a) and 4(b) in plan view from below.
[0030] FIG. 6 shows an enlarged portion of the nozzle plate
according to the invention from FIGS. 1 and 2 in cross-section
through the nozzles.
[0031] FIG. 7 shows a preferred embodiment of an individual nozzle
which takes the form of a modular insert which may be inserted into
a corresponding passage through a plate. The nozzle insert
comprises a vertically extending channel. In the figure shown, the
channel would be supplied from above with spinning composition,
which would then leave from the lower region of the channel under
pressure. The shape of the channel is initially cylindrical in the
direction of flow, then tapers conically with an angle .gamma. to
the vertical in the range from 10.degree. to 80.degree., preferably
in the range from 20.degree. to 70.degree., particularly preferably
in the range from 30.degree. to 60.degree., until the diameter D of
the channel cross-section is reduced to a size in the range from
0.05 mm to 0.5 mm, preferably in the range from 0.1 to 0.3 mm,
particularly preferably in the range from 0.12 to 0.18. The conical
region of the channel is followed by a cylindrical region of length
L. The same preferred L/D ratios as were discussed in the example
relating to FIG. 3 apply to the embodiment shown in FIG. 7.
* * * * *