KR102184274B1 - Apparatus for preventing entrainment of floating matters on free surfaces of ladle and tundish during continuous casting process - Google Patents

Abstract

In the continuous casting process according to an embodiment, a device for preventing mixing of floating matter on a free surface of a ladle and a tundish having discharge ports, respectively, is configured to be installed at the discharge port of the ladle and the tundish, and the device for preventing mixing of floating matters And a support portion installed on the plate and configured to support the plate with respect to the surface around each discharge port of the ladle and the tundish, and a ratio of the width of the plate to the radius of the discharge port of the ladle And a ratio of the width of the plate to the radius of the discharge port of the tundish is at least 1, respectively.

Description

A device to prevent mixing of floating matter on the free surface of ladle and tundish during continuous casting process{APPARATUS FOR PREVENTING ENTRAINMENT OF FLOATING MATTERS ON FREE SURFACES OF LADLE AND TUNDISH DURING CONTINUOUS CASTING PROCESS}

Hereinafter, the embodiments relate to an apparatus for preventing mixing of floating matter on the free surface of a ladle and a tundish during a continuous casting process.

When liquid in a container is discharged or sucked through a narrow port, dimples are often found on the free surface. When the swirling flow is caused by the Coriolis effect or external disturbance in the container, the dimple develops rapidly in the vertical direction and reaches the discharge port or pump inlet. This dimple penetration is called an air-core phenomenon. Air core phenomena during the liquid evacuation process cause serious problems for many industrial devices. For example, air core phenomena created by vortices in a liquid propellant tank cause fluctuations in the fuel supply rate. Since the effective drainage area occupied by the fluid in the liquid phase becomes narrow due to the air core, the fuel supply rate can be significantly reduced by the air core phenomenon. In a sump pump station, the air core can be formed by a vortex initiated by pump operation. Air entrained in the pump can cause cavitation on the pump blades, reduced pump efficiency, vibration and noise. In addition, according to the tundish discharging process in the continuous casting process, the slag floating on the molten metal can be entrained into the slab due to the air core phenomenon, which is a significant quality of the steel product. Cause defects. Therefore, a lot of research has been conducted to prevent this air core phenomenon.

Korean Patent Application Publication No. 10-2011-0028023 (published on March 17, 2011)

An object according to an embodiment is to provide an apparatus for preventing mixing of floating matter on free surfaces of a ladle and a tundish during a continuous casting process.

In the continuous casting process according to an embodiment, a device for preventing mixing of floating matter on a free surface of a ladle and a tundish having discharge ports, respectively, is configured to be installed at the discharge port of the ladle and the tundish, and the device for preventing mixing of floating matters And a support part installed on the plate and the plate, and configured to support the plate with respect to a surface around the discharge port of each of the ladle and the tundish, and a ratio of the width of the plate to the radius of the discharge port of the ladle or The ratio of the width of the plate to the radius of the discharge port of the tundish is at least 4, respectively.

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The ratio of the width of the plate to the radius of the discharge port of the ladle or the width of the plate to the radius of the discharge port of the tundish may be 8 or less, respectively.

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The ratio of the distance between the plate and the peripheral surface of the discharge port to the radius of the ladle discharge port or the ratio of the distance between the plate and the peripheral surface of the discharge port to the radius of the discharge port of the tundish is at least It can be 2 or more.

The ratio of the distance between the plate and the peripheral surface of the discharge port to the radius of the ladle discharge port or the distance between the plate and the peripheral surface of the discharge port to the radius of the discharge port of the tundish is 4 It can be below.

The support may include a plurality of protruding elements protruding from the plate.

The plurality of protruding elements may be arranged to be spaced apart from each other in a circumferential direction with respect to the center of the plate.

The apparatus according to an embodiment may prevent mixing of floating matter on the free surfaces of the ladle and the tundish during the continuous casting process.

In the continuous casting process according to an embodiment, the effect of the device for preventing the mixing of floating matter on the free surface of the ladle and tundish is not limited to those mentioned above, and other effects not mentioned are clearly to those skilled in the art from the following description. It will be understandable.

1 is a diagram of a continuous casting process system including a floating matter mixing prevention device according to an embodiment.
2 is a perspective view of an apparatus for preventing mixing of floating objects according to an exemplary embodiment.
3 is a conceptual diagram illustrating a device for preventing mixing of floating matters according to an embodiment of the present invention.
4 is a diagram of experimental equipment used to demonstrate the technical effect of the device for preventing mixing of floating matter according to an embodiment.
FIG. 5 is a graph comparing the discharge time and water height according to the height change of the device for preventing the mixing of floating matter from the bottom surface of the tank derived using the experimental equipment of FIG. 4.
6 is a graph comparing the discharge time and the water height according to the width change of the device for preventing the mixing of floating matter from the bottom surface of the tank derived using the experimental equipment of FIG. 4.
FIG. 7 is a graph showing the elapsed time of the water-air interface during drainage derived using the experimental equipment of FIG. 4, and when there is no device for preventing the mixing of floating objects (a), the mixing of floating objects having a width of 15 mm and a height of 10 mm is prevented. This is a graph comparing the case with the device (b) and the case with the device for preventing the mixing of floating matters having a width of 30 mm and a height of 20 mm (c).

Hereinafter, embodiments will be described in detail through exemplary drawings. In adding reference numerals to elements of each drawing, it should be noted that the same elements are assigned the same numerals as possible even if they are indicated on different drawings. In addition, in describing the embodiment, when it is determined that a detailed description of a related known configuration or function interferes with the understanding of the embodiment, the detailed description thereof will be omitted.

In addition, in describing the constituent elements of the embodiment, terms such as first, second, A, B, (a) and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, order, or order of the component is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected or connected to that other component, but another component between each component It should be understood that may be “connected”, “coupled” or “connected”.

Components included in one embodiment and components including common functions will be described using the same name in other embodiments. Unless otherwise stated, the description of one embodiment may be applied to other embodiments, and a detailed description will be omitted in the overlapping range.

1 is a diagram of a continuous casting process system including an apparatus for preventing mixing of floating matter according to an exemplary embodiment.

Referring to FIG. 1, the continuous casting process system 10 according to an embodiment includes a ladle 110, a tundish 120, a casting mold 130, and a ladle 110 and a tundish ( It may include a device 140 that suppresses the eddy current generated by the ladle 110 and prevents mixing of the floating material on the free surface of the ladle 110 and the floating material on the free surface of the tundish 120 into the casting mold 130. A first shroud 114 is installed between the ladle 110 and the tundish 120, and a second shroud 116 between the tundish 120 and the casting mold 130 ) Can be installed. A first valve 116 may be installed on the first shroud 114 to open and close the flow of fluid in a flow path leading from the ladle 110 to the tundish 120. A second valve 126 may be installed on the second shroud 124 to open and close a flow of fluid in a flow path leading from the tundish 120 to the casting mold 130.

The floating matter mixing prevention devices 140 are on the bottom surface of the ladle 110 and adjacent to the discharge port 112 of the ladle 110 and the discharge port 122 of the tundish 120, respectively, and the tundish 120 Can be installed on the bottom surface of the. Taylor vortex plays an important role in concentrating the axial momentum initiated by discharging fluid to the centers of each of the ladle 110 and tundish 120, and the ladle 110 and tundish 120 The strong axial momentum of the Taylor vortex aids in growth. Therefore, positioning of the floating matter mixing prevention devices 140 adjacent (or directly) to the discharge ports 112 and 122, respectively, helps to effectively block the interaction between the Taylor vortex and the axial momentum.

FIG. 2 is a perspective view of an apparatus for preventing mixing of floating objects according to an exemplary embodiment, and FIG. 3 is a conceptual diagram illustrating a device for preventing mixing of floating objects according to an exemplary embodiment.

Referring to FIGS. 2 and 3, the apparatus 140 for preventing mixing of floating matters according to an exemplary embodiment may include a plate 142 and a support part 144.

The plate 142 may have a shape suitable for effectively retarding the generation of air cores. For example, the plate 142 may have a disk shape such as a circle or an ellipse or several polygons.

The support 144 is configured to support the plate 142 against the bottom surface S1 of the ladle 110, in particular a surface S1 around the discharge port 112 of the ladle 110. Further, although not shown, the support 144 is configured to support the plate 142 against the bottom surface of the tundish, particularly a surface around the discharge port of the tundish.

The support 144 may include a plurality of protruding elements 1441. The plurality of protruding elements 1441 may protrude from the lower surface of the plate 142. For example, the plurality of protruding elements 1441 may have a cylindrical shape. The plurality of protruding elements 1441 may be arranged to be spaced apart from each other in the circumferential direction based on the center of the plate 142. Alternatively, the plurality of protruding elements 1441 may be arranged in a matrix form on the lower surface of the plate 142.

In one embodiment, the descending pattern of the fluid may depend on the width 2R of the plate 142. In a preferred embodiment, the descending pattern of the fluid may depend on the ratio of the width 2R of the plate 142 and the width 2r of the discharge port 112.

In one embodiment, the descending pattern of the fluid may not depend on the distance h between the plate 142 and the surface S1. In other words, the height of the plate 142 from the surface S1 may not affect the descending pattern of the fluid.

4 is a diagram of experimental equipment used to demonstrate the technical effect of the device for preventing mixing of floating matter according to an embodiment.

Referring to FIG. 4, there is shown an experimental equipment used in a liquid discharge experiment in order to prove the technical effect of the apparatus for preventing mixing of floating matter according to an embodiment. The inside of the tank T contained air and water at a set ratio. At this time, a discharge port is formed at the bottom of the tank T. For numerical analysis, the width of the discharge port was set to 10 mm, that is, the radius of the discharge port was set to 5 mm. In addition, the width of the tank T was set to 90 mm, the height of the water contained in the tank T was set to 250 mm from the bottom, and the height of the air layer was set to 100 mm from the free surface of the water. Here, the free surface was implemented by removing the top cover of the tank T. In addition, in order to implement a vortex phenomenon according to the discharge of water in the tank T, the motor (M) is connected to the shaft (S) connected to the tank (T) with a belt (B) and the motor (M) is driven to (T) was rotated. In order to capture the instantaneous fluid discharge pattern, the CCD camera C acquired an image image of the water contained in the tank T at a speed of 20 frames per second. Based on the image image received from the CCD camera C, the level of the liquid over time was measured through the computer P. Finally, an anti-floating device was placed adjacent to the discharge port of the tank as a prototype.

5 is a graph comparing the discharge time and the water height according to the height change of the device for preventing the mixing of floating matter from the bottom surface of the tank derived using the experimental equipment of FIG. 4.

Referring to FIG. 5, a graph showing a comparison according to the presence or absence of a floating material mixing prevention device and a comparison according to the height of a floating material mixing prevention device having a certain width is shown. In the category, "Rot" refers to the rotation of the tank, and "Supp" refers to a device for preventing incorporation of floats. Therefore, "No Rot" means that there is no rotation of the tank, and "No Supp" means that there is no device for preventing the mixing of floating matter.

In the first case without the device for preventing rotation of the tank and mixing of floating matters, the time taken for the water in the tank to be completely discharged, that is, the complete discharge time, took about 21 seconds.

On the other hand, in the second case where there is no device for preventing the mixing of floating matter and the tank is rotated, the rate of descent of the water level suddenly changes around 3 seconds after the start of discharge. This is due to air entrained to the discharge port by the generation of air core. The discharge flow rate decreased sharply after this time (about 3 seconds). In addition, the speed of lowering of the water level decreased. In preparation for the first case, the second case took almost twice as long as the complete discharge time.

On the other hand, when there is a device for preventing the mixing of floating matters, a sudden change in the discharge flow rate did not occur, and the complete discharge time was relatively significantly reduced compared to the second case. In addition, the instantaneous discharge flow rate became more uniform over the entire discharge time. This showed that the fluid descending pattern according to the water level was not significantly affected by the height of the floating matter mixing prevention device.

6 is a graph comparing the discharge time and water height according to the width change of the device for preventing the mixing of floating matter from the bottom surface of the tank derived using the experimental equipment of FIG. 4.

Referring to FIG. 6, a graph showing a comparison according to the width of the floating matter mixing prevention device spaced apart from the tank bottom surface at a constant height is shown. Here, "width" means the maximum length in the horizontal direction of the floating matter mixing prevention device. Therefore, if the floating matter mixing prevention device has a circular disk shape, "width" can also be interpreted as "diameter".

In the case where the width of the device for preventing mixing of floating matters having a width of 5 mm, that is, the width of the device for preventing mixing of floating matters relative to the radius of 5 mm of the discharge port, was relatively small, the water level decreased considerably during the first 4 seconds. On the other hand, as the width of the floating matter mixing prevention device increased relative to the radius of the discharge port of the tank, the abrupt change in the water level during initial discharge disappeared, and the initial descending speed of the water level significantly decreased. However, in about 17 seconds, the descending water level of the cases (W = 20mm, 30mm, 40mm) in which the width of the floating object mixing prevention device is relatively large is lower than that of the cases (W = 5mm, 10mm ) Has exceeded the descent level. Eventually, despite the size of the floating matter mixing prevention device, the complete discharge time was reduced. This means that if the width of the floating matter mixing preventing device is 20 mm or more, the width of the floating matter mixing preventing device hardly affects the descending pattern of the water level.

FIG. 7 is a graph showing the elapsed time of the water-air interface during drainage derived using the experimental equipment of FIG. 4, and when there is no device for preventing the mixing of floating objects (a), the mixing of floating objects having a width of 15 mm and a height of 10 mm is prevented. This is a graph comparing the case with the device (b) and the case with the device for preventing the mixing of floating objects having a width of 30 mm and a height of 20 mm (c).

Referring to FIG. 7, in the case of (a), it was confirmed that the dimples generated by the rotation of the tank were rapidly sucked into the discharge port in about 3 seconds. Air core remained during the discharge time. Since the air phase partially occupied the cross section of the discharge port, the discharge flow rate of water started to decrease after air core creation.

On the other hand, in the cases (b) and (c), no sudden inhalation of the dimples occurred. Sloshing, i.e. repeated up and down motion of the free surface, appeared in the center of the tank while the discharge continued. However, compared to the case of (c), the case of (b) showed a slightly faster drop in water level during the initial discharge period. After about 4 seconds, the speed of lowering the water level in the case (b) was considerably slowed. However, the complete discharge time was longer in the case of (b) than the case of (c).

As described above, when the width of the floating matter mixing prevention device is within an appropriate range, it is possible to effectively delay the generation of the air core, and it can be confirmed that it is advantageous in terms of the discharge rate of the fluid and the complete discharge time.

As described above, although the embodiments have been described by the limited embodiments and drawings, various modifications and variations are possible from the above description by those of ordinary skill in the art. For example, the described techniques are performed in a different order from the described method, and/or components such as a system, structure, device, circuit, etc. described are combined or combined in a form different from the described method, or other components Alternatively, even if substituted or substituted by an equivalent, an appropriate result can be achieved.

Claims (8)

In the apparatus for preventing mixing of floating matter on the free surface of a ladle and a tundish each having a discharge port during a continuous casting process,
The floating matter mixing prevention device is configured to be installed at the discharge port of the ladle and the tundish,
The floating matter mixing prevention device
A disk-shaped plate; And
A support part installed on the plate and configured to support the plate against a surface around each discharge port of the ladle and the tundish;
Including,
The ratio of the width of the plate to the radius of the discharge port of the ladle or the width of the plate to the radius of the discharge port of the tundish is at least 4 or more.
delete The method of claim 1,
The ratio of the width of the plate to the radius of the discharge port of the ladle or the width of the plate to the radius of the discharge port of the tundish is 8 or less, respectively.
delete The method of claim 1,
The ratio of the distance between the plate and the peripheral surface of the discharge port to the radius of the ladle discharge port or the ratio of the distance between the plate and the peripheral surface of the discharge port to the radius of the discharge port of the tundish is at least A device to prevent mixing of 2 or more floating objects.
The method of claim 5,
The ratio of the distance between the plate and the peripheral surface of the discharge port to the radius of the ladle discharge port or the distance between the plate and the peripheral surface of the discharge port to the radius of the discharge port of the tundish is 4 A device to prevent mixing of floating matters below.
The method of claim 1,
The support unit includes a plurality of protruding elements protruding from the plate.
The method of claim 7,
The plurality of protruding elements are spaced apart from each other in a circumferential direction with respect to the center of the plate and arranged to prevent mixing of floating matter.

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