U.S. patent application number 10/533438 was filed with the patent office on 2006-01-19 for method for producing a porous, plate-type metallic composite.
Invention is credited to Ulrich Muller.
Application Number | 20060014451 10/533438 |
Document ID | / |
Family ID | 29594648 |
Filed Date | 2006-01-19 |
United States Patent
Application |
20060014451 |
Kind Code |
A1 |
Muller; Ulrich |
January 19, 2006 |
Method for producing a porous, plate-type metallic composite
Abstract
A method of producing a porous, plate-shaped metallic composite,
wherein metallic fibers are compressed and fused together in a
single step.
Inventors: |
Muller; Ulrich;
(Huckelhoven, DE) |
Correspondence
Address: |
ROBERT W. BECKER & ASSOCIATES
707 HIGHWAY 66 EAST
SUITE B
TIJERAS
NM
87059
US
|
Family ID: |
29594648 |
Appl. No.: |
10/533438 |
Filed: |
October 30, 2003 |
PCT Filed: |
October 30, 2003 |
PCT NO: |
PCT/EP03/12045 |
371 Date: |
June 1, 2005 |
Current U.S.
Class: |
442/6 ; 442/13;
442/35; 442/376; 442/377 |
Current CPC
Class: |
Y10T 442/121 20150401;
Y10T 442/159 20150401; Y10T 442/109 20150401; G10K 11/168 20130101;
F23R 3/002 20130101; Y10T 442/655 20150401; Y10T 442/654 20150401;
B22F 3/002 20130101; B32B 15/14 20130101; F23M 20/005 20150115;
B23K 11/002 20130101 |
Class at
Publication: |
442/006 ;
442/013; 442/035; 442/377; 442/376 |
International
Class: |
D03D 15/00 20060101
D03D015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 31, 2002 |
DE |
102 50 716.3 |
Claims
1-14. (canceled)
15. A method of producing a porous, plate-shaped metallic
composite, including the steps of: providing metallic fibers, and
compressing and fusing said metallic fibers together in a single
step.
16. A method according to claim 15, wherein said providing step
comprises providing metallic fibers in the form of prefabricated
metallic fiber mats.
17. A method according to claim 15, wherein said metallic fibers
are derived from bulk material and are initially separated.
18. A method according to claim 15, wherein opposite flat sides of
said metallic composite are fused to respective cover layers in the
form of wire meshes.
19. A method according to claim 15, that is carried out
continuously to form an endless metallic composite.
20. A method according to claim 15, wherein said method is carried
out in inert gas.
21. A method according to claim 15, wherein said metallic fibers
are fused together via pulse fusing.
22. A method according to claim 21, wherein said pulse fusing is
capacitor pulse fusing.
23. A method according to claim 15, wherein the fusing step is
carried out in less than 1 s.
24. A method according to claim 23, wherein the fusing step is
carried out in less than 10 ms.
25. A method according to claim 15, wherein said metallic fibers
are subjected to pressure prior to or during the fusing step.
26. A method according to claim 25, wherein the pressure is
produced with a pressing force of 0.1 N/mm.sup.2 to 10
N/mm.sup.2.
27. A method according to claim 26, wherein said pressing force is
from 1.5 N/mm.sup.2 to 6.0 N/mm.sup.2.
28. A sound-dampening panel formed of metallic fiber fleece having
metallic fibers that are fused together, wherein said
fused-together fibers are disposed between two cover layers.
29. A sound-dampening panel according to claim 28, wherein said
metallic fiber fleece is fused to said cover layers.
30. A sound-dampening panel according to claim 28, wherein said
cover layers are in the form of wire meshes.
31. A gas burner insert formed of a metallic fiber fleece having
metallic fibers that are fused together, wherein said
fused-together metallic fibers are disposed between two cover
layers.
32. A gas burner insert according to claim 31, wherein said cover
layers are in the form of wire meshes.
Description
[0001] The invention relates to a method of producing a porous,
plate-shaped metallic composite. Also the subject matter of the
invention is a sound-absorbing panel.
[0002] The production of porous, plate-shaped metallic composites,
which can be used, for example, as light construction elements or
sound dampening panels, are known from the state of the art.
[0003] For example, DE 39 35 120 discloses a method of producing
metallic composite panels, according to which two outer,
non-perforated metallic panels having a bridging material in the
form of a metal grating of wire disposed between them are
interconnected. The special feature of this method is that the
grating intersections of the metallic grating, prior to a
connection of the metallic grating with the metallic panels, are
first rolled flat by means of a rolling process to the thickness of
a wire, so that thereafter the grating intersections of the
metallic grating can be welded or glued with the metallic panels.
Advantageously obtained in this manner is a metallic composite
panel that can still be further processed by a subsequent forming
process.
[0004] A further method of producing metallic composite panels is
known from DE 20 57 474. Disclosed are porous metallic fiber panels
as well as a method of producing the same. The method described
here is characterized by the use of a fiber fleece that at a
temperature between 1000 and 150.degree. C. is pressed in locally
determined regions with a pressure of 700 N/cm.sup.2 to 1200
N/cm.sup.2, whereby only in these predetermined regions is a
sintering of the fibers also effected. There thus results a
metallic fiber panel that is sintered only in certain regions, and
that has an adequately great strength, yet also has regions with a
relatively large fiber surface.
[0005] Additionally known from DE 199 24 675 is a sintering
metallurgical method for producing a filter body of smelt extracted
metallic fibers. This method is used, for example, for producing a
porous body, especially a filter body of fibers, in particular
metallic fibers. In this connection, it is provided that the loose
fibers, which are present as bulk material, are separated by
agitation, are filled into a mold, and a charge is subsequently
heated to sinter it. As a result of the sintering, there results a
solid and stable porous body that can be used, for example, as a
filter body. In addition to the previously described possibility of
use as a filter body, it is also known to use sintered metallic
fiber materials in the area of sound dampening. Thus, the use of
such sintered metallic fiber materials has proven itself, for
example, for reducing noise emission in gas turbines.
[0006] With all of the aforementioned methods, the sintering step
is typically effected at a temperature that is between the liquid
temperature and the solid temperature of the material that is used.
The fiber length and the fiber diameter of the fibers that are to
be interconnected by sintering can vary greatly, whereby the fiber
diameter can be in the range of 1 .mu.m to 250 .mu.m and the fiber
length can be in the range of between 50 .mu.m to 50 mm.
[0007] To prevent a premature oxidation of the fibers, the
sintering process is carried out in a vacuum oven. In this
connection, the actual sintering times are in the range of many
hours, whereby the material that is to be sintered is provided into
the sintering process in a mechanically compacted or initially
pressed state. The sintered bodies produced in this manner are cut
to size after the process has been carried out, and can then be
used, for example, as acoustical dampening material, and can be
placed, for example, in exhaust gas mufflers of gas turbines.
[0008] However, the known methods have the drawback that due to the
size of the sintering ovens that are available, it is possible to
produce only such sintered bodies that are limited in their
geometrical configuration in correspondence to the size of the oven
used. If, for example, sintered bodies of the aforementioned type
are produced that at least in their length exceed a size of, for
example, 1500 mm, this is not possible using the aforementioned
method. In order nevertheless to be able to produce such sintered
bodies, it is necessary to first produce relatively small sintered
bodies in a first method step that are then appropriately
interconnected in a second method step, for example being glued or
welded together. The drawback of carrying out such a method is that
it is not only time consuming but also expensive.
[0009] It is therefore an object of the invention, while avoiding
the aforementioned drawbacks, to provide a method with which while
simultaneously reducing manufacturing costs, it is possible to
produce a plate-shaped metallic composite of fibers of any desired
size, at least with regard to one dimension, that can be sintered.
The invention should also propose a sound-dampening panel.
[0010] To realize this object, the invention proposes a method of
producing a porous, plate-shaped composite according to which
metallic fibers are pressed and welded or fused together in a
single step.
[0011] In contrast to the methods known from the state of the art,
there consequently inventively results a material-flow connection
of the individual metallic fibers, not by sintering but rather via
fusion. This is not only relatively economical, but also opens the
possibility of being able to form a metallic composite of any
desired length, at least in one dimension.
[0012] For carrying out the inventive method, metallic fibers are
introduced into a welding or fusing device provided therefor. The
metallic fibers are preferably processed in the form of
prefabricated metallic fiber mats that are wound off from a roll,
for example as quasi endless mats. Alternatively, it is also
possible, where the metallic fibers are present as bulk material,
to possibly first separate them in a first step and subsequently to
supply them as loose metallic fiber material to the fusing device.
The introduction into the fusing device can be effected
continuously, so that in the further carrying out of the method,
metallic composite panels having an unlimited length dimension can
be produced. The fibers introduced into the fusing device are then
compacted and fused together in a single step, for which purpose
laminar electrodes are advantageously disposed on both sides of the
metallic composite that is to be formed, with the electrodes
serving on the one hand for fusing the individual metallic fibers,
and on the other hand also serving for the application of an
adequate pressure.
[0013] The fusing process is advantageously the pulse fusing
process, preferably the capacitator pulse fusing process, whereby
the electrodes that are used have a laminar area of preferably
between 10 mm.sup.2 and 25,000 mm.sup.2. A particular
characteristic of the capacitor pulse fusing process is the
relatively short duration of the actual fusing process, which is
generally less than is; in conjunction with carrying out the
inventive method, it can even be less than 10 ms.
[0014] Due to the very short and very high current pulse of up to
200,000 A, there is formed from fiber to fiber of the
compressed-together metallic composite an electrical resistance
that leads to heating of the material at that location and a
point-type fusing with the closest fiber. The specific welding or
fusing energy that is applied is in this connection 0.2 J/mm.sup.2
to 7.5 J/mm.sup.2.
[0015] Prior to and/or during the fusing process, the metallic
fibers of the metallic composite are subjected to a pressure,
whereby the pressure is preferably produced with a pressing force
of 0.1 N/mm.sup.2 to 10 N/mm.sup.2, preferably from 1.5 N/mm.sup.2
to 6 N/mm.sup.2.
[0016] The advantage of the inventive method is further that the
metallic composite, which is composed on a basis of individual
metallic fibers, due to the electrical charge that acts in a
shock-type manner, additionally has its structure compacted. As a
result, an overall greater compaction of the metallic composite can
be achieved during the fusing process.
[0017] Using a suitable automated device, which will not be
described in greater detail here, the metallic fibers, which are
present as bulk material or in the form of mats, can be endlessly
supplied to the electrodes in sections at least in one dimension.
In this connection, the width of the metallic composite can be
selected to be 10 mm to 2000 mm, preferably 250 mm to 1250 mm. The
fibers have an average diameter of 1 .mu.m to 250 .mu.m, preferably
from 30 .mu.m to 100 .mu.m. The metallic fibers that are used can
have the same thickness, but a different length, whereby precisely
by the use of metallic fibers having different lengths, a very
stable fiber structure, i.e. a fiber matrix, is formed during the
compression and fusion.
[0018] A metallic composite that is produced pursuant to the
inventive method can, subsequent to its manufacture, be finished
and used as a sound-absorbing medium, and can be placed, for
example, in a muffler system or exhaust gas pipe of a turbine. The
significant advantages over heretofore known metallic composites
that are produced by sintering, consists in the unlimited
measurements, at least relative to one dimension, as well as the
considerably more favorable manufacturing costs. Additionally, due
to the possibility of the capacitor pulse fusing process, the
thickness of the metallic composites can be influenced without
requiring a further finishing step, such as rolling. There also
results in this way an additional savings in cost, which is also
advantageous relative to the conventional process. A further
advantage is that the metallic composite produced pursuant to the
inventive method can be further processed in subsequent processing
steps. Thus, for example, it is possible via plastic shaping or
molding, for example by deep drawing, to also transform the
metallic composite produced pursuant to the method to geometrically
complex structures. Thus, for example, spherical shaped bodies can
also be formed. Since the metallic composite produced pursuant to
the inventive method is resistant to heat, it is particularly
suitable as sound dampening in combustion turbines. The inventively
produced metallic composite is also suitable as a gas burner insert
that advantageously enables a homogeneous combustion on the entire
surface of the burner.
[0019] To prevent oxidation during the fusing process, it is
possible pursuant to a further feature of the invention to carry
out the method in inert gas. Suitable inert gases are, for example,
argon, helium and the like.
[0020] Pursuant to a further feature of the invention, the two flat
sides of the metallic composite are respectively fused with a wire
mesh as a cover layer. The arrangement of such wire meshes is
advantageous to the extent that the method can to a large extent be
carried out independently of the length and diameter of the fibers
used, which can lead to ends of individual fibers extending out of
the metallic composites. To counteract this circumstance, both
sides of the fiber composite are fused with a wire mesh as a cover
layer. In this connection, a fusing of the wire can advantageously
be carried out at the same time as the fusing of the metallic
fibers, so that no additional step is required as a consequence of
the fusing of the cover layers.
[0021] With respect to the sound-dampening panel, to realize the
aforementioned object a sound-dampening panel is proposed that is
formed of a metallic fiber fleece, the metallic fibers of which are
fused together, that is disposed between two cover layers.
[0022] In contrast to conventional porous metallic fiber fleeces,
the individual metallic fibers of the inventive sound-dampening
panel are not connected with one another in a material-flowing
manner by sintering, but rather by fusing or welding. This permits
not only a relatively economical manufacture of the sound-dampening
panels, but it is also possible to continuously produce the
sound-dampening panels, at least with respect to one geometrical
dimension, so that a quasi endless metallic fiber fleece can be
produced. For the further use of the metallic fiber fleece, it is
then finished to length as required.
[0023] Pursuant to a further proposal of the invention, a metallic
fiber fleece is fused on both of its opposite flat sides with a
cover layer, which is preferably formed of wire mesh. In this way,
there results an on the whole sandwiched construction having two
cover layers that comprise wire mesh and between which the metallic
fiber fleece is disposed.
[0024] The inventive sound-dampening panel is advantageously
inherently stable, yet nevertheless permits a further processing in
a subsequent processing step. Thus, for example, it is possible to
further form the inventive sound-dampening panels into spherical
bodies by plastic shaping, for example by deep drawing. This was
not possible up to now with conventional sound-dampening panels
produced by sintering, so that the inventive sound-dampening panel
provides new possibilities, even for the further processing.
[0025] Due to the porous structure, the inventively produced
metallic composites are suitable in particular as sound-dampening
panels. In contrast to the conventional sintering process, the
originally present porosity of the metallic fibers that are joined
together to form the later metallic composite also remains to a
great extent present after a fusing of individual metallic fibers,
so that the inventive sound-dampening panels have a relatively
greater porosity than do the sound-dampening panels that are known
from the state of the art and are produced by sintering. The
inventive sound-dampening panels can therefore exhibit an improved
emission characteristic relative to conventional sound-dampening
panels.
[0026] A further possibility of use for the inventive metallic
composite is the use as a gas burner insert. An advantage in this
connection is the multiple applicability due to the possible
geometrical variety of shapes due, for example, to plastic shaping,
the controlled and determinable expansion during thermal expansion,
the low weight, as well as the guarantee of a homogeneous
combustion over the entire surface of the burner. In addition, the
inventive metallic composite offers a high reliability against
flame rebound, corrosion protection even at higher temperatures, a
high mechanical resistance to shock, as well as a low thermal
inertion.
[0027] Further advantages and features of the invention are derived
from the description with the aid of the following figures, which
show:
[0028] FIG. 1: in a schematic illustration, the inventive method
pursuant to a first step;
[0029] FIG. 2: in a schematic illustration, the inventive method
pursuant to a second step; and
[0030] FIG. 3: in a schematic illustration, the inventive method
pursuant to a third step.
[0031] FIGS. 1 to 3 show how to carry out the inventive method. In
this connection, a first method step is schematically illustrated
in FIG. 1, a second method step in FIG. 2, and a third step in FIG.
3.
[0032] Pursuant to the illustration of FIG. 1, in a first method
step the metallic fibers 1 as non-compressed fibrous material, are
overlaid on both opposite planar sides with a respective wire mesh
2. On those sides of the wire meshes 2 that respectively face away
from the metallic fibers 1, a respective laminar electrode 3 is
provided, both of which are respectively moved in the direction
toward the metallic fibers 1 and thus bring and press together the
wire meshes 2 and the metallic fibers 1 in the manner of pliers or
tongs. This method step is schematically illustrated in FIG. 2.
[0033] The electrodes 3, with a pre-defined force F, are moved
together, for example hydraulically, to such an extent until a
defined surface load i.e. a defined pressure, is applied to the
metallic fibers 1 and the wire mesh 2. At the same time as the
pressing together of the metallic fibers 1 and the wire meshes 2,
current is introduced into the electrodes 3 via the power lead 4.
The introduction of power is inventively effected via capacitors
that are not illustrated in this figure, whereby as a result of
abrupt discharge of the capacitors, a short and strong current
pulse of up to 200,000 A is conveyed through the wire meshes 2 and
the metallic fibers 1. As a consequence of the introduction of this
current pulse, electrical resistances are formed between the
individual metallic fibers, as a result of which the material at
these locations is locally heated up and is welded or fused in a
point-type manner with the closest fiber. To prevent oxidation
during this fusing process, the entire process is carried out in an
inert gas atmosphere.
[0034] FIG. 3 shows the finished metallic fiber composite, which is
built up in a sandwich-like manner and, as cover layers has two
wire meshes between which are disposed the metallic fibers 1, which
are pressed together and fused with one another. As a consequence
of the previously described fusing process, not only are the
individual metallic fibers 1 fused with one another, but rather
also the wire meshes 2 are fused with the metallic fibers 1, so
that an overall stable, porous and sound-absorbing metallic
composite results that nonetheless at the same time still enables
the possibility of a further processing by, for example, deep
drawing.
REFERENCE NUMERAL LIST
[0035] 1 Metallic Fibers [0036] 2 Wire Mesh [0037] 3 Electrode
[0038] 4 Power Lead [0039] F Pressing Force
* * * * *