GB2276437A

GB2276437A - A device for insufflating gas into molten metal

Info

Publication number: GB2276437A
Application number: GB9306436A
Authority: GB
Inventors: Ii Michael D Labate; Victor D Garcia; Jr Dallas F Mansell
Original assignee: Insul Co Inc
Current assignee: Insul Co Inc
Priority date: 1991-06-18
Filing date: 1993-03-27
Publication date: 1994-09-28
Anticipated expiration: 2013-03-27
Also published as: GB9306436D0; CA2091280A1; GB2276437B; CA2091280C

Abstract

A device for insufflating gas into a mass of molten metal in a vessel comprising a body member (12) having upper (16) and side (16A) surfaces positioned for engagement with said molten metal, a plurality of passageways (17, 17A) in the body member extending inwardly thereof from the upper surface and communicating with a gas supply manifold (24), the passageways being interconnected to one another at locations spaced from the manifold, so that gas flowing therethrough forms a plurality of streams of stirring gas and protective bubbles rising in said molten metal, so that swirling stirring motion is imparted to the molten metal and the bubbles move molten metal upwardly away from the device. <IMAGE>

Description

A DEVICE FOR INSUFFLATING GAS INTO NOLTEN METAL This invention relates to a device for insufflating gas into molten metal.

Prior structures of this type have generally employed pocket blocks having frustoconical openings therethrough, in which frustoconical plugs having similarly shaped metal shells thereabout are positioned so as to form an annular passageway upwardly through the opening in the pocket block. Such constructions are shown in the following LaBate-Insul Company U.S. Patents: 4,396,179, 4,483,520, 4,538,795, 4,632,367, 4,687,184, 4,725,047 and 4,840,356.

Additionally, U.S. Patent 4,568,066 to Grabner illustrates another version of the conventional pocket block and plug apparatus.

LaBate-Insul Company Patents U.S. 4,836,433 and 4,858,894 disclose pocket blocks and/or their equivalents in which gas conducting passageways are directly formed and U.S. Patent No. 4,535,975 to Buhrmann, et al. discloses a gas transmitting wall element in which a refractory brick is provided with a plurality of longitudinally extending grooves in the vertical sides thereof and encased in a metal box so that the grooves define passageways on the outer surfaces of the brick.

According to one aspect of the present invention, there is provided a device for insufflating gas into a mass of molten metal in a vessel having a refractory lining, the device forming, in use, part of said lining and comprising a body member of refractory material having a plurality of interconnected passageways within it and opening on one surface to be in contact with the molten metal and connected with gas supply means, said passageways being arranged in a web-like formation with some of said passageways extending in a first direction and others of said passageways extending in a second direction and said web-like formation of passageways being arranged to cause gas flowing therethrough in use to exit therefrom in streams of stirring gas and protective bubbles rising in said molten metal so that swirling stirring motion is imparted to said molten metal and said bubbles move molten metal upwardly away from said device.

According to another aspect of the present invention, there is provided a method of making a device for insufflating gas into molten metal, including the steps of providing a body comprising an interconnecting network of heat removable filaments, placing said body in a mould, adding refractory material to the mould around the filaments, applying heat to consume or liquefy said filaments, firing the refractory and removing the device so formed from the mould, said filaments thereby having formed a plurality of interconnected passageways in the device opening onto surfaces of the device.

The invention also extends to a ladle incorporating such a device.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:- Figure 1 is a vertical section through a device for insufflating gas into a mass of molten metal, with the device being in the form of a pocket block with its network of intercommunicating small passageways illustrated in enlarged detail; Figure 2 is a plan view of a modified pocket block with enlarged broken line representations of spiral and straight interconnecting passageways formed therein; Figure 3 is a perspective view of a portion of a pocket block with parts broken away and parts in cross-section illustrating in exaggerated detail the network of interconnecting passageways formed therein; and Figure 4 is an enlarged side view of a network of interconnecting members formed of synthetic resin filaments or cords in a preferred shape to be embedded in a pocket block and melted or burned and removed therefrom forming passageways as illustrated in Figures 1, 2 and 3.

By referring to Figure 1 of the drawings, a bottom (or lower wall) of a ladle or other vessel for molten metal is illustrated at 10 together with units 11 of a refractory lining units and a device for insufflating gas into molten metal in the form of a pocket block 12. A pipe 13 extends upwardly through an opening in the bottom of the ladle 10 and through an opening in the refractory lining and communicates with an opening 14 in the bottom of the pocket block 12, which opening 14 may be defined by a resin, ceramic or metallic pipe which communicates with a resin, ceramic or metallic cup 15 above it by way of an aperture in the bottom thereof.

Spaced thereabove communicating with the cup 15 and extending upwardly and outwardly to the upper and side surfaces 16 and 16A of the pocket block 12 there are a plurality of small interconnecting passageways 17 and 17A and preferably one or more individual upwardly extending passageways 18. The lower ends of the passageways 17 and 18 terminate above the apertured bottom of the cup 15 and all of them extend to the upper surface-16 of the pocket block 12. The interconnecting passageways 17A extend to the side surfaces 16A of the pocket block 12.

Preferably, but not necessarily, an anchor 19 with a loop 20 on its upper end is positioned in the pocket block 12 to form a pickup hook. A refractory erosion visual indicator 21, such as disclosed in LaBate-Insul Patent 4,744,544, is preferably embedded in the pocket block 12.

In order to form the network of interconnected gas conveying passageways 17 and 17A, a desirably-shaped, consumable or meltable, synthetic resin network of flexible shape retaining filaments or cords 22 and 22A is provided as best shown in Figure 4 of the drawings, the shape illustrated being exaggerated as to the thickness of the synthetic resin filaments 22 and the network desirably shaped, as for example in upstanding circular configuration with transverse portions is positioned in the pocket block 12 as it is formed of a suitable refractory. For example, as shown in Figure 1, the pipes 13 and 14 and the cup 15 are supported in a mould, not shown, a block of wax 23 as seen in Figure 4 is positioned in the cup 15 in the space in which a chamber forming a manifold 24 is to be formed and the desirably shaped network of synthetic resin filaments 22 is positioned on the block of wax 23 so that it extends upwardly to the level of the upper surface 16 and sideways to the sides of the pocket block to be formed thereabout so as to form the passageways 17 and 17A therein.

Additional resin filaments 25, preferably straight as seen in Figure 4, are positioned in the cup 15 in the mould so as to form the individual passageways 18 as seen in Figure 1.

The refractory is then added to form the pocket block as seen in Figures 1 and 3 with the network of interconnected synthetic resin filaments 22 and 22A and if desired the individual synthetic resin filaments 25 and the block of wax 23 are thus completely embedded in the refractory of which the pocket block 12 is formed. Instead of wax, synthetic resin could be used for the block 23 and wax could be used instead of synthetic resin for the filaments.

The pocket block with its embedded filaments and the cup 15 and pipe 14 is then removed from the mould and fired to an appropriate temperature to create a desired ceramic which will resist wear of molten metal supported thereby and of a temperature sufficient to liquefy or consume the network of interconnected synthetic resin filaments 22, 22A and 25 as well as the block of wax 23 or synthetic resin, as the case may be. The liquefied or combustible resin and/or wax drain or burn out of the refractory block and leave the desirable pattern of small interconnected passageways 17 and 17A therein communicating with a manifold 24 as formed when the block of wax 23 (or resin) liquefy or are consumed.

The size of the filaments 22, 22A and 25 can be varied to produce the desired small and/or very small and/or extremely small passageways 17 and 17A and 18 as seen in Figures 1 and 3 and that the cup 15 and the pipe 14 may also be formed of synthetic resin which will melt and drain away or be consumed simultaneously with the filaments 22, 22A and 23 so as to leave the desired arrangement of manifold and passageways in the pocket block thus formed.

The network of interconnecting synthetic resin cords or filaments 22 may be shaped in a number of configurations, for example in a spiral as shown in broken lines in Figure 2, and representing an alternative shape to that of Figure 1 and that the pattern of small or extremely small openings 26 in the upper surface 16 of the pocket block 12 which represent the upper ends of the passageways 17 are thus capable of being arranged in any desired pattern at any desired angle from vertical so that a desired stirring pattern of gas jets and gas bubbles can be achieved.

It will be appreciated that the use of a network of filaments or cords of synthetic resin or combustible materials enables the member thus formed to be of any desired size, design and shape so that the passageways which deliver the gas to the molten metal may be controlled so that the gas jets and bubbles formed in the molten metal bath by the gas flowing through the passageways can be arranged to result in the most efficient swirling and block penetrating pattern possible.

As envisaged above, other consumable materials can be substituted for the synthetic resin filaments to form a filament web-like construction by placing interconnecting and/or overlapping combustible strands such as cordage, cellulose based fibre compounds and carbon fibres so as to form the interconnecting passageways upon combustion.

It will be appreciated that the arrangement of interconnecting small gas conveying passageways formed in the pocket block results in an unusually efficient pattern of upwardly and horizontally extending passageways individually capable of producing small jets and bubbles of pressurised gas in a bath of molten metal, the passageways being so formed provide for equalisation of the gas pressure over the block's top and side surfaces thereby diminishing uneven erosion of the block, thus enhancing its performance and usual life expectancy.

Claims

CLAIMB:

1. A device for insufflating gas into a mass of molten metal in a vessel having a refractory lining, the device forming, in use, part of said lining and comprising a body member of refractory material having a plurality of interconnected passageways within it and opening on one surface to be in contact with the molten metal and connected with gas supply means, said passageways being arranged in a web-like formation with some of said passageways extending in a first direction and others of said passageways extending in a second direction and said web-like formation of passageways being arranged to cause gas flowing therethrough in use to exit therefrom in streams of stirring gas and protective bubbles rising in said molten metal so that swirling stirring motion is imparted to said molten metal and said bubbles move molten metal upwardly away from said device.

2. A device according to claim 1, wherein said refractory material is moulded into a uniform refractory block.

3. A device according to claim 1 or 2, wherein the refractory material is ceramic.

4. A device according to claim 1, 2 or 3, wherein said plurality of passageways have been formed by providing an interconnecting network of heat removable filaments, embedding said filaments in said refractory material and applying heat to consume or liquefy said filaments, thereby to produce said passageways.

5. A device according to claim 4, wherein said heat removable filaments are of various cross-sectional shapes and sizes whereby the cross-sectional shapes and sizes of said plurality of interconnecting passageways in said device are of the same cross-sectional shapes and sizes as said filaments when said network of filaments are removed by heating said device.

6. A device according to any one of the preceding claims, wherein said gas supply means includes a manifold chamber between a lower surface of said body member and an upstream end of said passageways.

7. A device according to claim 4 or 5 and 6, wherein said manifold chamber has been formed by providing a heat removable member engaging said heat removable filaments.

8. A device according to claim 6 or 7 and further comprising a gas supply passageway communicating with said manifold.

9. A device according to any one of the preceding claims, wherein some of said interconnected passages extend laterally of the device to open in side walls thereof in contact with molten metal.

10. A device for insufflating gas into a mass of molten metal, substantially as hereinbefore described with reference to the accompanying drawings.

11. A ladle incorporating a device according to any one of the preceding clailms.

12. A method of making a device for insufflating gas into molten metal, including the steps of providing a body comprising an interconnecting network of heat removable filaments, placing said body in a mould, adding refractory material to the mould around the filaments, applying heat to consume or liquefy said filaments, firing the refractory and removing the device so formed from the mould, said filaments thereby having formed a plurality of interconnected passageways in the device opening onto surfaces of the device.

13. A method according to claim 12, wherein said heat removable filaments are made of resin or wax.

14. A method according to claim 12 or 13, wherein a block of heat removable material is provided in a cup adjacent ends of said filaments on one side, thereby to form a manifold chamber on an upstream side of the passageways of the device.

15. A method according to claim 14, wherein said block is made of resin or wax.

16. A method of making a device for insufflating gas into molten metal, substantially as hereinbefore described with reference to the accompanying drawings.