ES2817854T3 - Vortex inhibitor - Google Patents

Abstract

A vortex inhibitor (20) for pouring molten metal from a discharge nozzle (14) consisting of: a meltable refractory body (22) having a geometrically proportioned shape so that its center of gravity is below its center of buoyancy and towards the apex of the pyramidal shape, whereby the body (22) is self-oriented in a position down from the apex (41) when supported in molten metal, wherein the body (22) comprises a hemispherical body having a top (26) and a vertex (41), and a plurality of constant dimension grooves (42, 44, 46, 48, 50, 52) extending between the top and the vertex (41) and comprising: an internal cone (28) tapering from an upper end (26) to the apex (41), a plurality of projections (30, 32, 34, 36, 38, 40) including a first projection that is projects outward from the inner cone (28) and extends from the top end (26) toward the vertex ice (41), where the first projection includes a triangular configuration that has a base aligned with the upper end and a corner that opposes the base and extends towards the vertex and where the internal cone (28) and the plurality of projections (30, 32, 34, 36, 38, 40) comprise a hemispherical shaped body (22); and a plurality of grooves (42, 44, 46, 48, 50, 52) extending from the upper end (26) towards the apex (41) and which are positioned on two sides of the first projection, wherein the plurality of grooves (42, 44, 46, 48, 50, 52) intersect at the corner of the first projection.

Description

DESCRIPTION

Vortex inhibitor

Cross reference to related patent applications

This application claims priority from US Provisional Patent Application No. 60 / 007,459, filed December 11, 2007, entitled: VORTEX INHIBITOR FOR MOLTEN METAL DISCHARGE HAVING CONSTANT DIMENSION GROOVES, in the name of Koffron et al.

Background

The present invention relates generally to a metal fabrication apparatus and more particularly to an apparatus for separating slag from molten metal when molten metal is transferred from a receptacle. This article is hemispherical in shape and has a plurality of constant-dimension grooves extending downwardly from its top.

In metal fabrication processes, the flow of molten metal through the discharge nozzle of a receptacle such as a furnace, tundish, or ladle induces a vortex in the molten metal above the discharge nozzle. At a certain level, the energy from the eddy creates a vortex, whereby the slag layer on top of the molten metal is sucked into the nozzle and mixes with the molten metal that is poured through the nozzle. . Various devices are known to inhibit the introduction of slag into the discharge nozzle in order to avoid contamination of the poured metal. Before such devices were introduced, it was necessary to terminate the pour by closing the nozzle while the molten metal is one level above the point where the suction action of the vortex draws the slag down towards the discharge nozzle. Such a process traps a large amount of molten metal in the receptacle and reduces the efficient production of the melt.

US Patent No. 4,494,734 to LaBate et al. discloses a dart incorporating a dependent guide member that can be hooked into the casting hole to direct the precise positioning of the plug body towards the casting hole. The patent describes alternative configurations of the plug body that are taught to cause a swirl of the metal. The patent teaches that visual observation of the swirling metal and slag indicates when the discharge of melt from the furnace is to be completed.

Many of the previously known devices for limiting slag flow through the discharge nozzle were in the form of plugs that are housed in the discharge nozzle to prevent further pouring through the nozzle. For example, US Patent No. 2,810,169 to Hofer describes the use of a slag dam, as well as a plug 3 that is mechanically controlled for placement during the pouring operation. However, such units are large and expensive to build, and many parts are subjected to the harsh environmental conditions of molten metal. Consequently, the cost of repairing or replacing the parts substantially increases metal fabrication costs.

Other known devices for separating slag and molten metal during discharge comprise bodies that are self-supporting in the molten metal layer. This is achieved by building the body with a specific gravity between the specific gravity of the molten metal and the specific gravity of the slag layer. One such device with such controlled density is a spherical body that is drawn through the vortex towards the nozzle and is housed in the nozzle to obstruct further flow. However, such a device is difficult, if not impossible, to remove and often requires replacement of the nozzle sleeve.

US 4,494,734 discloses a slag retaining device, comprising a manually insertable plug, incorporating a dependent guide member that can be hooked into the pouring hole, ensuring precise positioning of the plug body in a relationship of close with pouring hole.

US 5,044,160 describes a vortex inhibitor with a nozzle that includes a uniform meltable refractory body with a regular pyramidal shape.

US Patent No. 4,526,349 to Schwer describes an annular disk that has a specific gravity that allows it to separate slag at the interface between slag and steel. However, this patent also contemplates that a spherical body is drawn by the suction of the vortex towards the opening of the discharge nozzle to cut off the flow of fluid. The patent describes that two discrete items are necessary. While the ring is taught to counteract the effect of the vortex formed on the discharge nozzle, the sphere merely closes the pour when the slag is about to be introduced into the discharge nozzle. Consequently, the problems discussed above are found.

A particularly self-supporting device developed to inhibit vortex formation is disclosed in present Applicant's earlier US Patent No. 4,601,415. That patent defined a tapered, polygonal body designed to generally conform to the shape of the vortex along its length to extract energy from the swirling motion of the molten metal. Unlike known plug bodies Previously, the patented vortex inhibitor was taught to be self-steerable due to its vortex-tight shape. However, to ensure downward positioning of the apex, the patent also describes a charging means embedded in the refractory body. Furthermore, while the patent teaches that the shape of a polygonal cross section can be changed to adjust the degree of plugging or the choking effect as the body enters the discharge nozzle, it was found that by changing the shape of the inhibitor of vortex from the tetrahedral shape of the preferred embodiment could affect the stability of the orientation of the body. In particular, as the body is subject to external influences during placement in the molten metal bath or during movement of the receptacle from which the molten metal is being discharged, the geometric ratio can alter the desired downward orientation of the vertex. Furthermore, the use of a separate weighting medium, such as a core, substantially increases the complexity of producing the vortex inhibitor and has been disapproved.

Consequently, as with most technologies, there is room for improvement in the art of vortex inhibiting articles.

Compendium

The present disclosure overcomes the above-mentioned disadvantages by providing a vortex inhibitor according to claim 1.

The body includes a plurality of constant-dimension grooves that extend downwardly from its top. The body narrows from the top towards its apex. In this way, the center of gravity is provided below the center of buoyancy and closer to the vertex. As a result, the body orients its apex downward into the molten metal without the time consuming and laborious efforts required to embed a filler core within the refractory body.

In general, the vortex inhibitor of the present disclosure comprises a body made of a uniform meltable refractory material. It is to be understood that the term "uniform" does not require complete material homogeneity and includes the intermixing of shot, steel fiber, or other materials that can be consistently mixed with a meltable refractory material to adjust the specific gravity of the body. In either case, the specific gravity of the uniform mixture is selected so that it is buoyantly supported at the interface of the slag layer and the molten metal layer.

The body is substantially hemispherical in shape and has a plurality of grooves of constant dimension extending from its upper side toward its apex. This arrangement allows a constant drainage capacity whereby the deviation value of the liquid flow will be constant as the pouring hole wears. According to the constant drainage capacity provided, even though the pouring hole is provided as the center of the device and, in general, the article provides a fairly constant plugging effect. This results in about the same throughput as if the normal practice of allowing the casting hole to wear at a rate where the final casting discharge is about half the initial casting discharge time were adopted. Then, the drain from the container, which is normally the inverse of that function, becomes a constant output at the completion of the casting. Accordingly, the article of the present disclosure actually functions as a disc with slotted relief openings.

The configuration of the article of the present description allows the manufacturer to use less material in the production of the part. Therefore, it is less expensive to manufacture.

The general shape of the article would allow a hole through the center of the part, thus making it a very good candidate for a dart application as used in connection with a sacrificial rod, disclosed in US Pat. No. 6,723,275, for "Vortex Inhibitor With Sacrificial Rod".

Thus, the present disclosure provides a body that is simple to manufacture, since it is easily formed by pouring a single mixture into a mold. However, the body automatically self-orients so that its apex extends downward toward the discharge nozzle of a molten metal receptacle. As a result, the vortex inhibitor self-aligns within the vortex eddy caused by the discharge of molten metal. Furthermore, a vortex inhibitor body constructed in accordance with the present disclosure maintains the separation of the relationship of the center of gravity and the center of buoyancy regardless of the number of sides, projections, recesses, or other configurations used to deactivate the vortex-induced eddy. As a result, the vortex inhibiting body can be constructed independently of the throttling ratio necessary to interrupt the discharge of molten metal through the nozzle while maintaining the separation between the slag layer and molten metal in the receptacle during a pouring operation.

Brief description of the drawings

The present description will be more clearly understood with reference to the following detailed description of a preferred embodiment when read in conjunction with the accompanying drawings in which the same reference characters refer to similar parts throughout and in which:

FIG. 1 is an elevation view of a molten metal receptacle containing a vortex inhibitor constructed in accordance with the present disclosure;

FIG. 2 is a side elevation view of the vortex inhibitor shown in FIG. 1;

FIG. 3 is a top plan view of the vortex inhibitor shown in FIG. 1;

FIG. 4 is an apex view of the vortex inhibitor shown in FIG. 1; Y

FIG. 5 is a perspective view of the vortex inhibitor shown in FIG. 1 seen generally from the vertex.

Detailed description

Referring first to FIG. 1, a molten metal receptacle 10 is shown having a bottom wall 12 with a discharge nozzle 14. The receptacle 10 may be a furnace, ladle, tundish, or other form of receptacle into which molten metal is discharged through of nozzle 14. Regardless of the type of receptacle, receptacle 10 is shown containing a layer of molten metal 16. A slag layer 18, having a specific gravity less than the specific gravity of molten metal 16, rests on top of molten metal layer 16. A vortex inhibitor 20 according to the present disclosure is shown supported at the interface of slag layer 18 and molten metal layer 16 within receptacle 10.

Referring now to FIGS. 2 to 5, the vortex inhibitor 20 comprises a body 22 having a base 24 defined as a vertex and a top 26. An inner cone 28 is shown that is formed within a plurality of outwardly extending elements 30, 32, 34, 36, 38 and 40. The projection (or extension) elements 30, 32, 34, 36, 38 and 40 are separated by a similar number of grooves 42, 44, 46, 48, 50 and 52 of constant dimensioned width. It is to be understood that six outwardly extending elements are illustrated, but a greater or lesser number of elements may be used. The inner cone 28 ends at a vertex 41.

The diameter of the vortex inhibitor 20 is preferably greater than the diameter of the opening of the nozzle 14 (which may vary with use) so that only a portion of the body 22 becomes located within the nozzle 14. Due to the harsh environmental conditions within the furnace, the diameter of the vortex inhibitor 20 may be substantially larger than the diameter of the nozzle opening 14 so that erosion of body 22 (such as erosion of the projection (or extension) elements ) 30, 32, 34, 36, 38 and 40) does not substantially reduce the diameter of the outermost points of the vortex inhibitor 20 to less than the diameter of the opening of the nozzle 14, even if the diameter of the opening of the nozzle 14 grows larger with use.

As shown, if there is a general hemispherical shape of the body 22, the constant dimension grooves 42, 44, 46, 48, 50 and 52 in combination with the cone 28 are designed to provide a generally constant plugging effect. Therefore, formed in this way, the vortex inhibitor 20 can effectively fit and function within a hole that has an increasingly large size due to wear. This design allows the throughput to remain the same even if one follows the normal practice of allowing the hole to wear at a rate where the final casting discharge is half the initial casting discharge time. Then the drain, which is in an inverse of that function, becomes a constant set-out at the completion of the casting.

Having thus described the present disclosure, many modifications thereto will become apparent to those skilled in the art to which it belongs without departing from the scope of the present disclosure as defined in the appended claims.

Claims (3)

1. A vortex inhibitor (20) for pouring molten metal from a discharge nozzle (14) consisting of: a meltable refractory body (22) having a geometrically proportioned shape so that its center of gravity is below from its center of buoyancy and towards the apex of the pyramidal shape, whereby the body (22) is self-oriented in a position down from the apex (41) when supported in molten metal, wherein the body (22) comprises a hemispherical body having an upper part (26) and a vertex (41), and a plurality of grooves of constant dimension (42, 44, 46, 48, 50, 52) extending between the upper part and the vertex (41 ) and comprising: an internal cone (28) that tapers from an upper end (26) to the apex (41), a plurality of projections (30, 32, 34, 36, 38, 40) including a first projection projecting outward from the inner cone (28) and extending from the upper end (26) toward the apex (41) , wherein the first projection includes a triangular configuration having a base aligned with the upper end and a corner opposing the base and extending toward the vertex and wherein the inner cone (28) and the plurality of projections ( 30, 32, 34, 36, 38, 40) comprise a hemispherical shaped body (22); and a plurality of grooves (42, 44, 46, 48, 50, 52) extending from the upper end (26) towards the vertex (41) and which are positioned on two sides of the first projection, wherein the plurality of grooves (42, 44, 46, 48, 50, 52) intersect at the corner of the first projection. 2. The vortex inhibitor of claim 1, wherein the plurality of grooves (42, 44, 46, 48, 50, 52) have a constant width. The vortex inhibitor of claim 1, wherein the inner cone (28) includes a hemispherical shape that includes a substantially constant radius from the upper end (26) to the apex (41).