CASTING SYSTEM WITH A DEVICE FOR APPLYING FLUID ON A CAST STRIP

Abstract

A casting system (1) having a reservoir (2) for a fluid (3), such as, in particular, liquid metal, a dispensing chamber (5) connectable by a connection (4) with the reservoir, and an application device (7) with which the fluid is spreadable to a predetermined width and with which it is spread on a movable strip (9), with the connection between the dispensing chamber and the application device being formed as a closed tubular connection including a plurality of tubes (6) arranged in a pattern corresponding to a pattern of a spread hand-held fan.

Description

RELATED APPLICATION

This application is a continuation-in-part application of U.S. application Ser. No. 12/734,761 filed Jul. 16, 2010, which is a national stage application of an international application PCT/EP2008/009662 filed Nov. 14, 2008 and which claims priority of German application DE 10 2007 055 346.5 filed Nov. 19, 2007, all of the three applications being incorporated herein by reference thereto.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a casting system with an application device for applying fluid such as, in particular, liquid metal onto a cast strip.

2. Description of the Prior 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.

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 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 B1. 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.

SUMMARY OF THE INVENTION

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 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 that includes a plurality of closed pipes arranged relative to each other in a pattern corresponding to a pattern of a spread hand-held fan.

Providing a tube pattern corresponding to the pattern of a spread handheld fan permits spreading of the fluid over a greater strip width.

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.

With regard to the discharge of fluid, it is advantageous when the end profile of the pipes is flattened, so that an optimal discharge can take place. Further, flattening of the pipe end profile permits to increase the outlet velocity of the fluid and to adapt it to the height of the stream as it exits from the tubes. Furthermore, different flattening of the central and outer tubes provides for a more uniform distribution of the fluid over the strip width.

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.

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;

FIG. 1A a schematic view of a casting system according to the present invention with a device for applying a fluid, with delivery pipes arranged in a fan-shaped manner;

FIG. 2 a schematic view of the application device; and

FIG. 3 a cross-sectional view of the application device shown in FIG. 2.

DETAILED DESCRIPTION OF THE 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 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 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 so that the pipes 6 are spread somewhat in a manner of a hand-held fan, as shown in FIG. 1A.

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 pipes 6 at an end of the end profiles 13 are flattened and/or widened in the plane of the application device 7.

Advantageously, the pipes 6 can be formed as heat-insulating pipes 6, e.g., as a double-wall pipes, so that the liquid metal that flows through the pipes 6, retains 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 direction R of the metal. The sidewise demarcation of the spread can be staggered or continuous.

Claims

1. A casting system (1), comprising a reservoir (2) for liquid metal; a dispensing chamber (5) connectable by a connection (4) with the reservoir; and an application device (7) with which the liquid metal is spreadable to a predetermined width onto a movable strip (9),

wherein the connection between the dispensing chamber and the application device is formed as a closed tubular connection (6) having a plurality of closed pipes, and the application device (20) has a bottom (21) with side walls (22, 23),

wherein at the end of the device (20) remote from the dispensing chamber, a closure wall (26) is provided, and between the closure wall (26) and a remote wall (25), spaced from the closure wall, an outlet opening (27) is provided, and

wherein the plurality of closed pipes (6) is arranged in a pattern corresponding to a pattern of a spread hand-held fan.

2. A casting system according claim 1, wherein the inlet (12) for liquid metal is located, during operation of the system, in a region of the dispensing chamber (5) beneath the surface of the fluid (3) in the dispensing chamber (5).

3. A casting system according to claim 1, wherein the outlet opening (27) is provided in the bottom (21).

4. A casting system according to claim 1, wherein the side walls (22, 23) and the closure wall (26) have essentially the same height.

5. A casting system according to claim 1, wherein the side wall (22, 23), the closure wall (26), and the remote wall (25) extend perpendicular to the bottom (21) and wherein the remote wall (25) has a smaller height than the side walls (22, 23) and the closure wall (26).

6. A casting system according to claim 1, wherein end profiles (13) of the pipes (6) are flattened.