MXPA06004904A - Rippled surface stopper rod system - Google Patents

Abstract

The present invention concerns stopper rod system for use in a metallurgical vessel, comprising a stopper rod and a nozzle. At least one of the stopper rod nose (42,56) and the internal surface of the nozzle bore comprise (43,62) a plurality of ripples that are arranged such that the size of a flow channel between the stopper rod nose and the internal stopper rod when the stopper rod system is in an open position discontinuously increases in size as a function of the distance downstream from the point of contact between the stopper rod and the nozzle.

Description

For two-letter codes and other abbreviations, teferto ihe "Guid-ance Notes on Codes and Abbreviations" appearing at the beginning-ning ofeach regular issue of the PCT Gazette.

WAVE BARREL SURFACE BAR SYSTEM CROSS REFERENCE TO RELATED REQUESTS This application claims the benefit in accordance with 35 U.S.C. §120 of the filing date of the provisional application of E.U.A. 60 / 516,902 filed on November 3, 2003.

FIELD OF THE INVENTION The present invention generally relates to an apparatus for regulating the speed of metallic flow out of a container containing liquid metal. More specifically, the present invention relates to an improved sealing bar system.

DESCRIPTION OF THE RELATED TECHNIQUE In the processing of molten metals or liquids, for example steel, the flow of liquid metal comes from a metallurgical container, such as a pot, in a tundish. The liquid metal then proceeds through the tundish into a mold. At or near the bottom of the tundish, the liquid metal flow is controlled outside the tundish and in the mold. Generally, the flow is controlled using a shutter system.

The sealing rod system is comprised of a movable obturator bar and a nozzle. The nozzle has a hole through which the liquid metal is allowed to flow. The flow of liquid metal out of the trough through the orifice of the nozzle is generated by the action of gravity. The sealing rod has an end or edge immersed in the liquid metal that engages with an inlet portion of the nozzle orifice, so that if the sealing edge moves in contact with the nozzle, the nozzle orifice is blocked and the flow Liquid metal stops. When the edge of the sealing rod moves away from the contact with the nozzle, an opening between the sealing edge and the nozzle orifice is formed, allowing the liquid metal to flow from the container through the nozzle orifice. Through a precise movement of the sealing rod, the liquid metal flow rate is regulated, while maintaining a close proximity between the edge of the sealing rod and the nozzle orifice. In this way, adjusting the size of the opening regulates the flow rate of the liquid metal. In particular, the present invention relates to the shape of the edge of the sealing rod and / or the shape of the surface of the mouthpiece. A problem in traditional seal systems is the obstruction or restriction of the flow of liquid metal by the deposition and aggregation of non-metallic materials at the sealing edge and / or at the surface of the nozzle orifice. This deposition leads to difficulties in the proper regulation of the liquid metal flow. As a result of the formation of clogging deposits, the desired velocity of the liquid metal flow may be impossible to maintain leading to the early completion of the process. Also, the metal flow can arise suddenly if a portion of an obstruction tank escapes and is dragged by the metal flow. Poor regulation of the liquid metal flow as induced by the obstruction leads to defects in the quality of the metallic products. Prior busbar systems have attempted to deal with the problem of clogging using uneven honeycomb geometry, or by introducing gas into the metal flow through a porous element at the sealing edge. Examples of such prior sealing rod systems are described in Japanese Patent No. 62089566-24 / 04/87 and US Pat. No. 5,071,043. However, the use of uneven surfaces as taught in Japanese Patent 62089566-24 / 04/87 leads to a poor regulation of the metallic flow, since the size of the opening is not a uniform function of the separation between the orifice. nozzle and the sealing edge. This uneven geometry also causes problems in the seal between the sealing edge and the nozzle orifice when it is necessary to interrupt the metallic flow since the gaps in the uneven surfaces are deflected by the liquid metal flow thus trapping the liquid metal in the voids in the where they can block the flow by freezing. The patent of E.U.A. No 5No. 071,043 discloses the use of a porous sealing lip that allows the introduction of bubbles of an inert gas such as argon into the metallic flow. The introduction of gas helps to reduce the clogging by providing bubbles to which the non-metallic particles in the liquid metal can preferably be fixed, thus reducing the formation in the sealing rim or nozzle orifice. However, the gas injected through the sealing lip generally does not form a uniform distribution of gas bubbles through the metal flowing through the opening. The gas follows the path of least resistance and can reach the liquid metal and form bubbles only on one side of the opening, or only in portions of the metal flow. When this occurs, the obstruction is asymmetric, leading to uneven flow through the opening, and, in turn, to poor regulation of the metal flow. The present invention corrects the deficiencies of the prior sealing rod systems by providing a sealing rod system with a uniquely designed sealing edge and a nozzle orifice that controls the scale and location of turbulence in the metal flow. The design of the present reduces deposition by obstruction, and improves the distribution of gas bubbles in the metallic flow when the gas is introduced into the system.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides a sealing rod system for use in a metallurgical vessel. The sealing rod system comprises a sealing rod having an edge at one end thereof, and the nozzle having a hole therein, the opening having an internal surface. The sealing bar edge and the inner surface of the nozzle orifice have a point of contact when the sealing rod system is in the closed position. At least one sealing rod edge and the inner surface of the nozzle orifice comprise a plurality of corrugations that are arranged so that the size of a flow channel between the edge of the sealing rod and the internal sealing rod when the bar system shutter is in an open position increment discontinuously in size as a function of the distance downstream of the contact point. Another embodiment of the present invention provides a sealing rod for use in a sealing bar system. The sealing bar system comprises the sealing rod having an edge at one end thereof, and a nozzle having a hole therein, the opening having an internal surface. The sealing bar edge and the inner surface of the nozzle orifice have a point of contact when the sealing rod system is in the closed position. The sealing rod edge comprises a plurality of corrugations which are arranged so that the size of a flow channel between the edge of the sealing rod and the internal sealing rod when the sealing rod system is in an open position increments discontinuously the size as a function of the distance downstream from the point of contact.

Another embodiment of the present invention provides a nozzle for use in a sealing bar system. The sealing rod system comprises a sealing rod having an edge at one end and the nozzle having a hole therein, the opening having an internal surface. The sealing bar edge and the inner surface of the nozzle orifice have a point of contact when the sealing rod system is in the closed position. The nozzle comprises a plurality of corrugations which are arranged so that the size of a flow channel between the sealing bar edge and the internal sealing bar when the sealing rod system is in the open position increases discontinuously in size as a function of the distance downstream of the point of contact.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view of a typical tundish used in the processing of liquid metal. Figure 2 is a cross-sectional view of traditional sealing rod systems. Figure 3 is a cross-sectional view showing the flow patterns located in a traditional sealing bar system.

Figure 4 is a cross-sectional view showing the flow patterns located in a sealing bar system as described in Japanese Patent No. 62089566-24 / 04/87. Figure 5 is a cross-sectional view of a sealing bar system in accordance with one embodiment of the present invention. Figure 6 is a cross-sectional view of a cross-sectional view of the sealing bar system of Figure 5, showing localized flow patterns. Figure 7 is a cross-sectional view of a sealing rod system in accordance with an alternative embodiment of the present invention. Figure 8 is a cross-sectional view of a sealing bar system in accordance with an alternate embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Figure 1 illustrates a traditional aresta configuration. On the ridge 1, a shutter bar 2 having a central axis 6 is aligned with the central axis 5 of the nozzle 3 and is used to regulate the flow of liquid metal through an opening 4. Figure 2 illustrates several alternative geometric configurations of the traditional shutter bar systems. The sealing rod 7 has a round or hemispherical edge that engages the rounded entry surface 8 of the nozzle orifice. Alternatively, the sealing rod 9 has a pointed or conical edge which engages the conical or tapered nozzle orifice inlet 10. Alternatively, the sealing rod 11 has a multiple radius or bullet-shaped edge. Figure 3 is a close view around the adjustment area in a traditional configuration such as that illustrated in Figure 2. The sealing bar edge 12 is positioned in relation to a nozzle orifice 13 to form an opening 15 that regulates the flow liquid metal represented by flow lines 14. The opening 15 lies along the closest proximity line between the sealing edge 12 and the nozzle orifice 13. Downstream of the opening 15, the flow lines can be detached from the liquid. the surfaces of the sealing rod edge 12 and the nozzle orifice 13 to cause uncontrolled turbulent currents as represented by the arrows 16. Turbulent streams are formed in regions of the liquid flow downstream of the opening 15 adjacent to the edge surface obturator 12 or on the interior surface of the nozzle orifice 13. Turbulent streams may appear and disappear in those two regions in an uncontrolled and unpredictable way. The size or scale of turbulent currents also varies over time. Variations in scale and location of the turbulent currents generated in the flow downstream of the minimum opening can affect the flow regulation to cause variation in the flow velocity even when the sealing position and thus the size of the opening, is fix Figure 4 illustrates an uneven surface as described in Japanese Patent 62089566. As shown in Figure 4, the sealing bar edge surface 17 represents multiple recesses 19. For illustrative purposes, only the surface of the obturator 17 in the figure 4 represents an uneven surface with voids, although the reference also teaches that the nozzle orifice may also have an uneven surface that represents similar voids. Thus, in Figure 4, the nozzle orifice surface 18 is shown as a rectifiable arc. The line 20 is tangential to the general curvature of the obturator edge surface 17 and connects to this surface in the aperture and extends in the general direction of the metal flow downstream of the aperture. Lines 21, 22, 23, 24, 25 and 26 are examples of lines perpendicular to line 20 and are sequentially additional to the opening. The lengths of several lines are proportional to the size of the flow channel that is formed downstream of the opening. It is clear that the size of the flow channel does not increase smoothly in the downstream direction as the position along the line 20 increases. In fact, the size of the flow channel increases rapidly at the entrance to each hole and subsequently decreases in the lower section (further downstream) of each hole. For example, line 22 is greater than line 21, line 23 is greater than line 22, but line 24 is less than line 23 and line 25 is less than line 24. Line 26 is greater than line 24. line 25 as the comment position below approaches the next gap. As used herein, both in the specification and in the claims, the term "flow channel", when used in connection with the shutter bar, is used to define the area between the sealing bar edge and a tangential line. at the sealing rod edge and parallel with the flow direction of the liquid metal at the point of contact between the sealing rod edge and the inner surface of the nozzle orifice. Similarly, as used herein, both in the specification and in the claims, the term "flow channel", when used in conjunction with the nozzle, is used to define the area between the interior surface of the nozzle orifice and a line tangential to the inner surface of the nozzle orifice and parallel to the flow direction of the liquid metal at the point of contact between the sealing bar edge and the inner surface of the nozzle orifice. It should be noted that the flow channel increases in size where the uneven surface is hollowed out, and thus, the rough voids are diverted by the liquid metal flow. The deviation of the voids allows the liquid metal to be trapped in the voids, resulting in a longer residence time for the trapped liquid compared to the liquid flowing near it. The trapped liquid can also freeze inside the gaps causing clogging of the liquid metal flow. This uneven geometry also causes problems in the seal between the sealing edge and the nozzle orifice when it is necessary to interrupt the metallic flow. Attention is now directed to Figure 5, which illustrates one embodiment of a sealing bar system of the present invention. The sealing rod edge 42 and the outlet nozzle orifice 43 shown are shown in the closed position. At the contact point 44, a tangential line 45 has been drawn tangentially to the surface of the sealing edge and extends downstream of the contact point. The variation of the distance between the tangential line 45 and the sealing rod edge 42 downstream of the contact point 45 is illustrated by the lines perpendicular to the tangential line 45. The lines 47, 48, 49 and 50 are a series of said perpendicular lines in a sequentially increased distance from the point 44. These lines illustrate that in this embodiment of the present invention, the surface of the sealing bar edge 42 comprises a plurality of depressions or corrugations. The corrugations are formed to form a flow channel between the tangential line and the sealing bar edge 42 which progressively increases in size, but in a gradual or discontinuous manner, as the distance downstream from the contact point 44 Increase When the sealing rod edge 42 moves away from contact with the nozzle orifice 43, the opening will be formed in the region of the contact point 44 and the flow channel between the tangential line and the sealing edge will increase in a discontinuous manner as that a distance downstream from the opening increases. For example, comparing lines 47 and 48 with lines 48 and 49, line 48 is greater than line 47, while line 49 is only slightly larger or of the same length as line 47. Thus, the difference in length between lines 48 and 47 significantly greater than the difference in length between lines 49 and 48. The wavy shape of obturating edge 42 provides for this discontinuous increase in the size of the flow channel. It should be noted that the flow channel size does not decrease as a function of the distance downstream from the opening. Instead, the size of the flow channel downstream of the opening increases in a series of steps. In a preferable configuration, first, a small increase in size (as a function of the distance of the contact point 44) adjacent the contact point 44 is used to ensure good closure of the sealing system. This is preferably followed by a larger increase, followed by a smaller increase or even no increase, followed by a larger increase, followed by a smaller or no increase, etc. Figure 6 illustrates the regulation area of one embodiment of the invention. The corrugated seal rod edge 56 is positioned relative to the nozzle orifice 62 to form an opening in the region 51 that regulates the flow of liquid metal represented by the flow lines. The opening lies along the closest proximity line between the sealing bar edge 56 and the nozzle orifice 62. Downstream of the opening, the flow lines are detached from the surfaces of the sealing bar edge 56 and form controlled turbulent currents as represented by the arrows 54, 55, and 60. Downstream of the point 53, the distance between the tangential line and the surface of The sealing edge increases rapidly in a first step causing the flow to detach from the sealing edge and generate a first region of turbulent streams as shown by arrow 54. Likewise, other regions of turbulent streams are formed downstream of other steps in where the distance between the tangential line 52 and the sealing edge surface increases rapidly, as illustrated by the arrows 55 and 60. Thus, in the invention, the location and scale of the turbulent flow regions are controlled by the Location and depth of the ripples on the surface of the sealing edge. In this embodiment of the invention, the deficiencies of the above shutter bar systems are connected by providing a shutter bar system with a uniquely designed shutter edge that controls the scale and location of turbulence in the metal flow. Controlled turbulence reduces the rate of deposition by obstruction in the sealing edge by continuously sweeping any non-metallic particle. Furthermore, if the gas is introduced into the system through the sealing edge, the controlled turbulence adjacent to the sealing edge surface distributes the gas bubbles uniformly around the sealing edge to further inhibit any deposition by obstruction.

Figure 7 illustrates a further alternative embodiment of the present invention. In this embodiment, the surface of the nozzle orifice 71 is formed into corrugations to form a flow channel between the tangential line and the nozzle orifice 71 that progressively increases in size, in a discontinuous manner, as the distance downstream of the point of contact 57 increases. This discontinuous increase in the size of the flow channel is similar to that described above in relation to Figures 5-6. At the point of contact 57 between the sealing bar edge 70 and the nozzle orifice 71 a tangential line 58 has been drawn tangentially to the surface of the nozzle orifice 71 extending downstream of the contact point. The wavy shape of the nozzle orifice 71 provided that the size of the flow channel between the tangential line and the nozzle orifice 71 does not decrease as a function of the distance downstream of the contact point 57. Instead, the channel size flow increases as the distance downstream of the opening increases, in a series of steps, with first a low increase adjacent to the point of contact to ensure a good closing, followed by a rapid increase, followed by a slow increase or even no increase, followed by a rapid increase, followed by a slow increase or no increase, etc. This causes the formation of turbulent flow regions in the flow channel adjacent to the nozzle orifice surface downstream of the passages where the distance between the tangential line and the nozzle orifice surface rapidly increases. In this way, the shutter rod system of this embodiment of the present invention controls the location and scale of the turbulent streams. Figure 8 shows another embodiment of the invention wherein the sealing edge 81 and the nozzle orifice 83 are corrugated. In this embodiment, as described above with respect to the above embodiments, the flow channel between the tangential line of the nozzle orifice and the nozzle orifice surface and the flow channel between the tangential line of the sealing edge and the edge surface. The obturator progressively increases in size, in a gradual manner, downstream of the opening. This controls the turbulence in the liquid metal flow adjacent to the nozzle orifice surface and adjacent the sealing edge surface downstream of the opening. Obviously, numerous modifications and variations of the present invention are possible. Therefore, it should be understood that within the scope of the following claims, the invention can be practiced in another way than specifically described.

Claims (15)

NOVELTY OF THE INVENTION CLAIMS

1. - A sealing rod system for use in a metallurgical container, comprising a sealing rod having an edge at one end thereof, and a nozzle having a hole therein, the orifice having an internal surface, the edge of which sealing rod and the inner surface of the nozzle orifice having a contact point when the sealing rod system is in the closed position; characterized in that at least one sealing bar edge (42) and the inner surface of the nozzle orifice (43) comprises a plurality of corrugations that are arranged so that the size of a flow channel when the sealing bar system is located in the open position increment discontinuously in size as a function of the distance downstream of the contact point (44).

2. The shutter bar system according to claim 1, further characterized in that the size of the flow channel remains the same or increases downstream of the contact point (44).

3. The sealing rod system according to claim 1, further characterized in that the increase in size of the flow channel due to the corrugation closest to the point of contact (44) is greater than the increase in size of the flow channel due to to the ripple immediately downstream of the ripple closest to the point of contact (44).

4. The sealing rod system according to claim 1, further characterized in that the increase in size of the flow channel due to each successive undulation is alternately greater and smaller than the latter with each successive undulation downstream of the point of contact ( 44).

5. The sealing rod system according to claim 1, further characterized in that the sealing rod edge (42) comprises the plurality of corrugations.

6. The sealing rod system according to claim 1, further characterized in that the internal surface of the nozzle orifice (43) comprises the plurality of corrugations.

7. The sealing rod system according to claim 1, further characterized in that the sealing rod edge (42) and the internal surface of the nozzle orifice (43) comprises a plurality of corrugations.

8. A sealing rod for use in a sealing rod system, the sealing rod system comprises the sealing rod having an edge and an end thereof, and a nozzle having a hole therein, the orifice has a surface internal, the sealing rod edge and the inner surface of the hole have a contact point when the sealing rod system is in the closed position; characterized in that the sealing rod edge (42) comprises a plurality of corrugations which are arranged so that the size of a flow channel when the sealing rod system is in an open position increments discontinuously in size as a function of the distance downstream of the point of contact (44).

9. The shutter bar according to claim 8, further characterized in that the size of the flow channel remains the same or increases downstream of the contact point (44).

10. The shutter bar according to claim 8, further characterized in that the increase in flow channel size due to the ripple closest to the point of contact is greater than the increase in size of the flow channel due to the immediately current ripple. below the corrugation closest to the contact point (44)

11. The shutter bar according to claim 8, further characterized in that the increase in size of the flow channel due to each successive corrugation is alternately greater and less than the last with each successive undulation downstream of the contact point (44).

12. A nozzle for use in a shutter system, the shutter system comprises a shutter bar having an edge at one end thereof, and the nozzle has a hole therein, the orifice has an internal surface, the sealing bar edge and the inner surface of the hole have a point of contact when the sealing rod system is in the closed position; characterized in that the internal surface of the nozzle orifice (43) comprises a plurality of corrugations that are arranged so that the size of the flow channel when the shutter system is in the open position increments discontinuously in size as a function of the distance downstream from the point of contact (44).

13. The nozzle according to claim 8, further characterized in that the flow size remains the same or increases downstream of the contact point (44).

14. The nozzle according to claim 8, further characterized in that the increase in size of the flow channel due to the ripple closest to the point of contact is greater than the increase in size of the flow channel due to the ripple immediately downstream. from the wave closest to the point of contact (44).

15. The nozzle according to claim 8, further characterized in that the increase in size of the flow channel due to each successive corrugation is alternately greater and smaller than the last with each successive corrugation downstream of the contact point (44).