Note: Descriptions are shown in the official language in which they were submitted.
CA 02705297 2012-03-02
CASTING SYSTEM WITH A DEVICE
FOR APPLYING A CASTING STRIP
Technical Field
The invention relates to a casting system with an application device for
applying fluid
such as, in particular, liquid metal onto a cast strip, in particular,
comprising a fluid
reservoir, a dispensing chamber connectable with the reservoir, and an
application device
with which fluid is spreadable to a predetermined width onto the strip.
State of the Art
In the state of the art, known are horizontal casting systems in which liquid
steel as fluid is
fed from a reservoir in a dispensing chamber and from the dispensing chamber
to an
application device for applying liquid metal onto a movable about rollers,
continuous strip.
The liquid steel is fed from the reservoir into the dispensing chamber more or
less
continuously and therefrom by the application device, essentially without a
large height
difference, onto a cooled movable continuous strip that, as a rule, is a metal
strip. There,
the liquid metal is carried with a casting speed and cooled and is so
processed in a metal
strip.
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It is essential that the applied liquid metal is applied uniformly with
respect to
the casting width and thickness and with a thin layer onto the movable strip
because otherwise a non-uniform cast metal strip is produced.
Advantageously, this is effected by having the width of the dispensing chamber
to correspond to the predetermined strip width, and the liquid metal then
flows
parallel from the dispensing chamber through the application device onto the
movable strip. This, however, requires dispensing chambers with an increased
width, so that different dispensing chambers in accordance with respective
strip
width were required.
The application can be effected with the dispensing chamber having a smaller
width than the width of the casting strip, so that the liquid metal is widened
to
the predetermined casting width in the application device and is so
distributed.
The drawback consists in that the uniform thickness and distribution is not
optimally achievable, and damaging thickness variations occur. This is also a
result of heat losses by the liquid metal as it flows from then dispensing
chamber toward the movable strip, which causes irregular casting behavior of
the partially cooled liquid, with the liquid metal not being adequately
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spreadable and, therefore, non-uniformly cooled. The produced surface waves
reduce the quality which basically affects the value and usefulness of the end
product.
The devices described above are disclosed, e.g., in European Patent EPO 962
271 B l. This document discloses a system of casting metal strips with a
reservoir for supplying a dispensing chamber with fluid metal, with the liquid
metal flowing from the dispensing chamber through a channel to a widening
device for applying metal on a movable continuous strip. Here, the above-
mentioned problems of unevenly cast strips occur.
Disclosure of the Invention, Objects, Solution, Advantages
It is an object of the present invention to provide a casting system with a
device
for applying fluid, in particular, metal onto a cast strip and with which the
drawbacks of the state of the art are minimized or even completely eliminated.
According to the invention, this object is achieved with a casting system
having
in particular, a reservoir for a fluid, such as, in particular, liquid metal,
a
dispensing chamber connectable by a connection with the reservoir, and an
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application device which spreads the fluid to a predetermined width and with
which it is spread on a movable strip, and wherein the connection between the
dispensing chamber and the application device is formed as a closed tubular
connection.
In such casting system, it is advantageous when the tubular connection is a
closed pipe. According to another embodiment, it may be appropriate when the
tubular connection includes a plurality of closed pipes. With closed pipes,
the
free surface of the fluid is reduced. Thereby, an increased measure of heat
insulation is achieved and, therefore, the liquid metal is not cooled very
much.
It is further advantageous when the plurality of closed pipes is arranged
beneath
and/or next to each other. According to a further embodiment, it may be
appropriate when the plurality of closed pipes is arranged parallel to each
other.
According to yet another embodiment it may be appropriate when the plurality
of closed pipes is arranged relative to each other in a fan-like manner.
Those can be so formed that the pipes at their end adjacent to the dispensing
chamber lie closer to each other than at their opposite ends.
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With regard to the discharge of fluid, it is advantageous when the end profile
of the at least
one pipe is flattened and/or spread, so that an optimal discharge can take
place.
According to still a further advantageous embodiment, it may be appropriate
when the
inlet for the fluid, or for liquid metal, is located, during operation of the
system, in a region
of the dispensing chamber beneath the surface of the fluid or the fluid metal
in the
dispensing chamber.
Accordingly, in one aspect the present invention resides in a casting system
comprising a
reservoir for a fluid, a dispensing chamber connectable by a connection with
the reservoir;
and an application device with which the fluid is spreadable to a
predetermined width and
with which it is spread onto a movable strip, wherein the connection between
the
dispensing chamber and the application device is formed as a closed tubular
connection,
and the application device has a bottom with side walls, wherein at an end of
the
application device remote from the dispensing chamber, a closure wall is
provided and
between the closure wall and a remote wall, an outlet opening is provided.
Further improvements are described hereafter.
Brief Description of the Drawings
Below the invention will be described in detail based on an exemplary
embodiment with
reference to the drawings.
The drawings show:
Fig. 1 a schematic view of a casting system according to the present invention
with a device for applying a fluid, in particular liquid metal or liquid
steel onto a cast strip;
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Fig. 2 a schematic view of the application device; and
Fig. 3 a cross-sectional view of the application device shown in Fig. 2.
Preferred Embodiment of the Invention
Fig. 1 shows schematically a casting system 1 according to the present
invention. The casting system 1 has a reservoir 2 in which preferably a fluid
such as fluid metal is produced, e.g., warmed up and/or liquefied or made
available. Through the pipe 4, the liquid metal reaches a dispensing chamber 5
from which it is fed to the application device 7 and is distributed over a
predetermined width 8 and is applied to a movable metal strip 9. The metal
strip 9 is a continuous strip movable around a pair of rollers 10, with only
one
roller 10 being shown in Fig. 1. The other roller cannot be seen. The
continuous metal strip 9 is wound about both rollers 10, forming a closed
strip.
According to the inventive embodiment of the casting system shown in Fig. 1,
the pipe 6 is closed so that the free surface of the fluid is reduced.
Inasmuch as
the pipe serves as heat insulation and, therefore, the flowing-through liquid
metal hardly cools before it spreads toward the application device 7 and is
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applied to the movable metal strip 9 and is cooled there further. Thereby,
essentially, a uniformly cast metal strip 11 is produced. By forming the
closed
pipe 6 as connection between the dispensing chamber 5 and the application
device 7, the heat losses of the liquid flowing-through metal are reduced
because the free surface is reduced. It is further advantageous to form the
connection as the closed pipe 6 because inserting of the liquid metal 3 in the
region of the closed pipe 6 can be dispensed with because apart from then
application device 7, hardly any or no free surface is available that could
lead to
cooling or oxidation of the liquid metal.
Further, the advantages of the inventive device consists in that the pipe 6
with
its inlet 12 is located in the region of the dispensing chamber 5 beneath the
surface of the liquid metal, so that during the operation, the pipe 6 is
located
beneath the level of the liquid metal. Thereby, the surface waves, which are
produced upon flow of the liquid metal in the dispensing chamber, cannot
spread sufficiently strongly against the liquid metal in the pipe, so that the
casting process is not influenced very strongly, and the cast product thereby
is
advantageously influenced with respect to the surface evenness. It is also
advantageous that based on the arrangement of the inlet 12 of the tube in the
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region of the dispensing chamber beneath the liquid surface, upon flowing
through, the pressure loss takes place, which also causes decoupling of fluid
oscillation and flows in the chamber 5 from those in pipe 6, so that fluid
oscillations and flows in the pipe are again reduced. It is further
advantageous
that because of all of this, the volume of the dispensing chamber can be
retained
small.
Instead of the shown pipe 6, several pipes 6 can be used which are arranged
between the application device 7 and the dispensing chamber 5. E.g., two or
more pipes 6 can be arranged parallel to each other and/or above each other.
Also, pipes 6 can be provided which spread somewhat in a fan-shaped manner.
Pipe 6 or pipes 6 advantageously have a discharge geometry of the end profile
13 which insures a uniform discharge of the liquid metal. Thereby, it can be
achieved that the pipe 6 at an end of the end profile 13 is flattened and/or
widened in the plane of the application device 7.
Advantageously, the pipe 6 can be formed as a heat-insulating pipe 6, e.g., as
a
double-wall pipe, so that the liquid metal that flows through the pipe 6,
retains
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its temperature substantially unaffected, and an unavoidable temperature
reduction is advantageously minimized.
Fig. 2 shows schematically an application device 20, and Fig. 3 shows its
cross-
section. The device 20 has a bottom 21 and two opposite side walls 22, 23.
The liquid metal flows from the pipe 6 conventionally over the bottom 21 in
the
direction of arrow R toward a remote wall 25 the height of which is so
selected
that it is lower than both side walls 22, 23. The liquid metal flows over the
wall
25 and flows between the wall 25 and a closure wall 26 through an opening 27,
so that the stream of the liquid metal is essentially deflected downwardly by
90 . The closure wall 26 is so formed that it extends essentially
perpendicular
to the flow direction of the liquid metal with respect to the bottom 21.
Viewing
perpendicular to the bottom, the closure wall height is so selected that it is
essentially equal to the height of both side walls 22, 23.
The side walls 22, 23 advantageously are so formed that they spread from the
region 24, in which the liquid metal is fed to the device 20, in the direction
toward the both walls 25, 26 transverse to the expanding direction or flow
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direction R of the metal. The sidewise demarcation of the spread can be
staggered or continuous.
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List of Reference Numerals
1 Casting system
2 Reservoir
3 Fluid, liquid metal
4 Pipe
Dispensing chamber
6 Closed pipe
7 Application device
8 Width
9 Movable metal strip
Roller
11 Cast metal strip
12 Inlet
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13 End profile
20 Application device
21 Bottom
22 Side wall
23 Side wall
24 Region
25 Wall
26 Closure wall
27 Opening
28 Flow direction
29 Section
30 Region
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