GB2147091A - Expandable, consumable stopper plug for steel making and handling vessels - Google Patents

Abstract

An improved stopper plug for sealing a tap hole in a molten metal receptacle comprising a radially expandable hollow elongated conical shape 13 formed of fibrous refractory material and a circular disc member 17 positioned thereon for expanding said conical shape within said tap hole when said circular disc member is moved inwardly thereof, a rod 19 having an enlarged portion 20 arranged to engage said circular disc member and move the same inwardly of the conical shape so as to expand said conical shape into sealing engagement with said tap hole. <IMAGE>

Description

SPECIFICATION Expandable, consumable stopper plug for steel making and handling vessels This invention relates to plugs for sealing the flow of metal from molten metal receptacles such as steel making furnaces, ladles, and the like.

Prior art devices of this type have relied on a number of different plugs or stoppers. See for example U.S. Patents 3,540,627, 4,010,936 and 4,030,709.

In Patent 3,540,627 a conical metal plug is attached to the end of a supporting rod and has a conical pad positioned thereover, the conical pad being formed of a layer of refractory fibers, such as alumina silica fibers, and a layer of glass fibers, the metal plug and its conical pad being insertable in the passageway defined by a tap hole in a molten metal receptacle.

Patent 4,010,936 discloses a stopper plug in a shape corresponding exactly to the shape of the tap hole and formed of non-porous refractory material, organic fibrous substance, and inorganic fibrous substance together with a combustible substance, the material forming a porous molding which is elastic and capable of shrinking and deformation so that it will remain in the tap hole of the vessel under nominal pressure of the molten metal and will deform and be extruded from the tap hole by the increasing pressure of the molten metal when the vessel is tilted.

Patent 4,040,709 discloses the use of a ceramic plug in the shape of a hollow cone over a solid backing plug which is maintained in place until the molten metal solidifies against the plug to seal off the tap hole.

The present invention discloses a novel, expandable, hollow cone-shaped stopper plug and a wedge-shaped member movable therein to expand the same in the tap hole of a molten metal receptacle so as to effectively seal the tap hole for a predetermined time.

An expandable, consumable stopper plug for steel making and handling vessels wherein a blunt nosed hollow refractory plug is formed of fibrous refractory materials, clay-like refractory materials consumable materials and a suitable binder to form an expandable, stretchable and deformable plug having means for expanding and deforming the same movably arranged therein.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a cross sectional side elevation of a stopper plug according to the invention; Figure 2 is an exploded side elevation with parts in cross section and parts broken away showing the stopper plug and a tool for expanding the same; Figure 3 is a cross sectional side elevation of the expandable stopper plug and the tool for expanding the same with broken lines showing the plug and tool in non-expanded relation and solid lines showing the plug and tool in expanded relation; and Figure 4 is a section through a wall of a molten metal receptacle and a tap hole therein showing the stopper plug therein.

Referring to Fig. 4 of the drawings, a portion of a molten metal receptacle 10 may be seen having a tapping block 11 therein defining a cylindrical orifice 1 2. An expandable consumable stopper plug 1 3 is shown in expanded position in the cylindrical orifice 1 2.

The stopper plug may be seen in Fig. 1 of the drawings to comprise a blunt nosed, hollow, conical body member 13, the nose portion 14 of which is relatively thicker than the wall portions extending therefrom. A steel cap insert 1 5 is positioned in the cavity 1 6 defined by the hollow body member 1 3 and immediately inwardly of and in contact with the material of the blunt nose portion 14 of the stopper plug.A round tapered member 1 7 having a central aperture 1 8 therethrough is positioned inwardly of the open end of the hollow body member of the stopper plug and is movable into the cavity 1 6 toward the steel cap 1 5 so as to expand and enlarge the hollow body member 1 3 deforming the wall portions thereof in an action which will securely position the stopper plug in the cylindrical orifice 1 2 in the molten metal receptacle 10 hereinbefore described.

In order that the hollow body member 1 3 forming the stopper plug may be quickly and efficiently expanded in sealing relation to a tap hole or the like, an applicator rod 1 9 is provided as best seen in Figs. 2 and 3 of the drawings, the applicator rod 1 9 having a metal disc 20 positioned thereon inwardly of an end 21 of the rod 19, the other end of the rod 1 9 being preferably provided with a suitable handle configuration 22.

The length of the rod 1 9 between the metal disc 20 and the end 21 is predetermined so that upon the end 21 of the rod 1 9 being positioned through the central orifice 1 8 in the round tapered member 1 7 and moved toward the steel cap 1 5, the metal disc 20 will engage the round tapered member 1 7 and move it inwardly of the hollow body member 1 3 to the position shown in solid lines in Fig. 3 of the drawings so as to distort and expand the hollow body member 1 3 until the end 21 of the applicator rod 19 reaches the steel cap 1 5 whereupon any further movement imparted the applicator rod 1 9 will distort the material of the blunt nose 1 4 of the hollow body member 1 3 and limit the movement of the round tapered member 1 7 and the expansion and distortion of the hollow body member 13.

It will thus be seen that the expandable, consumable stopper plug is moved into the tap hole and distorted and expanded by the wedging action imparted to the hollow body member of the plug by the round tapered member 1 7 as it is moved by the applicator rod 1 9 which is then removed.

In order that the hollow body member 1 3 of the stopper plug will retain its desirable consistency and hot metal stopping properties for a predetermined period of time, it is preferably formed of material comprising a mixture of fibrous refractory material such as FIBERFRAX as described in U.S. Patent No.

3,124,854, or CERAFELT, a product of Johns-Manville Company, in a range of approximately 8% by weight to approximately 25% by weight. These are alumina-silica fibers, dolomite in a range of approximately 32% to approximately 64% by weight, sodium silicate in a range of approximately 8% by weight to 16% by weight, and sawdust in a range of approximately 18% by weight to 27% by weight.

The material from which the stopper plug is formed is completely mixed to a uniform consistency which is essential in the expanding and distortion of the material when the plug is inserted in the tap hole and expanded as herein before described.

In addition to the materials above mentioned, mineral wool, such as blast furnace slag fibers may be incorporated and silica, quartz, magnesia, olivine, mullite, aluminum oxide, chamotte, magnesite or perlite may be incorporated with the dolomite or in place of the same. Resin binders, such as phenolformaldehyde resins, urea-formaldehyde resins, and furan resins may be used in place of the sodium silicate, all in substantially the same proportions. Other combustible substances such as paper pulp and wood flour may be used in addition to the sawdust and/ or in place of same, again in substantially the same proportions.It is essential that the proportions of the dolomite or its alternate substances be sufficient in any of the mixtures to insure the desirable consistency of the material from which the hollow body member 1 3 of the stopper plug is formed so as to enable it to be deformed and expanded as hereinbefore described.

It will be recognized that the proportions of combustible and/or disintegrable materials are such that the life of the stopper plug when subjected to molten metal can be readily predetermined. The consistency and/or density of the material also comprises a factor in determining the life expentancy of the plug when subjected to molten metal.

As disclosed herein the stopper plug is formed of the herein before disclosed materials so as to have a predetermined life whereupon the consumable and/or disintegrable or combustible materials incorporated therein will react and/or oxidize to weaken or change including disintegration of the material of the plug so as to open the tap hole which has been sealed thereby.

It will occur to those skilled in the art that tap holes in molten metal receptacles become enlarged by being worn away to irregular configurations by molten metal flowing therethrough. The expandible consumable stopper plug disclosed herein easily accommodates such irregular shaped tap holes as the construction, materials and arrangement of the walls and nose of the plug body distort and expand outwardly as a result of forward pressure applied to the plug in the tap hole as hereinbefore described. The expansion and distortion of the plug thus fills any cavity limited only by the initial diameter measure of the plug itself with the filled tap hole remaining filled for the desired predetrmined time whereupon the consumable and/or disintegrable characteristics of the material of the plug act to open the tap hole.

In a typical metal receptacle the tap hole will be found to vary from two to four inches (50.8 to 101.6mm) in its initial diameter and the self-expanding consumable stopper plug of this invention is accordingly preferably formed so that the blunt nose is approximately three inches (76.2mm) in diameter, the opposite open end of the conical body member thereof being from eight to ten inches (203.2 to 254 mm) in diameter and the walls of the conical body member being approximately two inches (50.8mm) thick and the overali length of the expandable, consumable stopper plug being between twenty five and thirty inches (635 to 762 mm).

Those skilled in the art will recognize that these dimensions may be very considerable without affecting the utility, time factor and deformable expandable properties of the stopper plug.

A typical and satisfactory analysis of the refractory materials of which the stopper plug is formed may comprise silicon dioxide in an amount between 31% and 36% by weight, calcium dioxide in an amount between 21 % and 26% by weight, aluminum oxide in an amount between 11 % and 15% by weight, magnesium oxide in an amount between 3% and 6% by weight with the amounts of the several ingredients being sufficient to provide for an ignition loss of from 25% to 28% and wherein the density, pounds per cubic inch, is between .0075 Ibs. and .0105 Ibs.

Claims (7)

1. A stopper plug for sealing a tap hole in a molten metal receptacle for a predetermined time, wherein the plug is in a hollow elongated conical shape with means for expanding said conical shape within a tap hole, said hollow elongated conical shape being formed of a refractory material, a fibrous substance and a binder, said means for expanding said conical shape comprising a cross sectionally circular disc member positioned in said hollow elongated conical shape, a rod having a disc thereon which is arranged to engage said cross sectionally circular disc member whereby movement of said rod in one direction moves said cross sectionally circular disc member inwardly of said hollow conical shape and the disc on said rind holds said cross sectionally circular disc member in transverse relation to said hollow conical shape so as to expand said hollow conical shape into sealing engagement with said tap hole.

2. A stopper plug according to Claim 1, wherein the refractory material is at least one of silica, quartz, magnesia, olivine, mullite, aluminum oxide, chamotte, dolomite, magnesite or perlite.

3. A stopper plug according to Claim 1 or 2, wherein the fibrous substance is at least one of an inorganic fibrous substance selected from the group consisting of aluminum silicate, rock wool and slag wool.

4. A stopper plug according to Claim 1, 2 or 3 wherein the consumable and/or disintegrable material is at least one of a group consisting of paper, sawdust and wood flour.

5. A stopper plug according to Claim 1, 2, 3 or 4, wherein the binder is at least one of phenol-formaldehyde resin, a urea-formaldehyde resin, a furan resin or sodium silicate.

6. A stopper plug for sealing a tap hole in a molten metal receptacle set forth in any one of Claims 1 to 5 and wherein a metal member is positioned in said hollow conical shape adjacent the closed end thereof so as to limit the inward movement of said rod and disc thereon and said cross sectionally circular body member with respect to said closed end of said hollow conical shape.

7. A stopper plug for sealing a tap hole substantially as herein before described with reference to and as illustrated in the accompanying drawings.