GB2150868A - Porous plug assemblies for molten metal vessels e.g. ladles - Google Patents
Porous plug assemblies for molten metal vessels e.g. ladles Download PDFInfo
- Publication number
- GB2150868A GB2150868A GB08427491A GB8427491A GB2150868A GB 2150868 A GB2150868 A GB 2150868A GB 08427491 A GB08427491 A GB 08427491A GB 8427491 A GB8427491 A GB 8427491A GB 2150868 A GB2150868 A GB 2150868A
- Authority
- GB
- United Kingdom
- Prior art keywords
- plug
- assembly
- sleeve
- aggregate
- porous
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000002184 metal Substances 0.000 title claims abstract description 22
- 230000000712 assembly Effects 0.000 title description 6
- 238000000429 assembly Methods 0.000 title description 6
- 239000011819 refractory material Substances 0.000 claims abstract description 9
- 239000000919 ceramic Substances 0.000 claims abstract description 8
- 239000007787 solid Substances 0.000 claims abstract description 6
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 4
- 230000035699 permeability Effects 0.000 claims abstract description 4
- 238000005245 sintering Methods 0.000 claims abstract description 4
- 239000010959 steel Substances 0.000 claims abstract description 4
- 210000002268 wool Anatomy 0.000 claims abstract description 4
- 239000000463 material Substances 0.000 claims description 4
- 239000013043 chemical agent Substances 0.000 claims description 2
- 230000000295 complement effect Effects 0.000 claims 1
- 239000003795 chemical substances by application Substances 0.000 abstract description 2
- 230000003628 erosive effect Effects 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 9
- 239000011449 brick Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 1
- 229910001570 bauxite Inorganic materials 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 235000014380 magnesium carbonate Nutrition 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
- B22D1/002—Treatment with gases
- B22D1/005—Injection assemblies therefor
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The porous plug assembly comprises a plug (1) of porous refractory material that has a height substantially less than that of a vessel bottom lining (7), the plug being coaxially nested within and located at the upper end of a bore (2) in a non-porous ceramic or other refractory sleeve (3) having a height substantially equal to that of the vessel bottom lining, a second plug (9) of a porous refractory material having a higher gas permeability than that of the first plug being coaxially nested within and located at the lower end of the sleeve bore; a gas-tight mounting (16, 18) for the second plug base being provided to enable a gas pipe (14) to be connected to the assembly and means (20) are provided to retain the first, upper plug and the second, lower plug in their relative positions in the sleeve bore. The unoccupied space within the sleeve may be filled with steel wool or refractory aggregate (21) and the aggregate may be coated with a glaze/sintering agent to fuse/sinter the aggregate into a solid mass in the event of leakage of molten metal due to erosion and failure of the upper plug. <IMAGE>
Description
SPECIFICATION
Porous plug assemblies
This invention relates to porous plug assemblies to be removably inserted in the bottom of a refractory lined vessel for molten metal to enable a gas or gases to be bubbled through the molten metal.
Bottom bubbling has particular application in the continuous casting of steels.
The vessel may be a ladle, a tundish or a runner; although most applications are for ladles.
A known porous plug assembly consists of a generally frusto-conical plug of porous refractory material that tapers from its base to its head, has a height approximately equal to the thickness of the vessel bottom into which it is to be mounted, has a non-porous ceramic or other refractory sleeve about the side walls of the plug to leave the plug's head and base free, and has a gas-tight mounting to the plug base to enable a gas pipe to be coupled to the assembly; this mounting is often in the form of a metal shell covering the base of the plug and the sleeve and extending at least part-way up the circumference of the sleeve. The plug assembly is usually installed in the vessel bottom by mortaring the assembly into a nest brick assembly in the vessel bottom lining that is coaxially aligned with a port in the vessel bottom.
In assemblies of this type, the plug head is exposed to and eroded by the molten metal which necessitates the regular replacement of the plug assembly. The number of casts for which any one plug assembly could safely be used depends upon individual operating conditions but could typically be between 7 and 20; in use, a plug assembly would be replaced after a given number of casts irrespective of its condition. Thus the assembly has to be regularly replaced and it is a major disadvantage that the actual replacement can only be done after the ladle has cooled, typically taking some six hours with consequent loss of production.
It is one object of the present invention to overcome the above disadvantage and produce a porous plug assembly that can safely be replaced in a hot vessel.
A second porous plug assembly consists of a plug of porous refractory material that has a height substantially less than that of a vessel bottom lining into which the assembly is to be inserted, the plug being coaxially nested within and located at the upper end of a bore in a non-porous ceramic or other refractory sleeve; a gas-tight mounting for the plug base being provided to enable a gas pipe to be connected to the assembly.
The danger with plug assemblies of this second type is that the short plug can fail and leak molten metal. It is proposed in United Kingdom Patent
Specification No. GB 2094954A (Flogates Limited) to provide a sliding gate valve to control any such leakage. However, any metal leakage has first to be detected and then action taken to close the valve and seal the assembly.
It is a further object of the present invention to provide a porous plug assembly having built-in, fail-safe provisions against metal leakage due to failure of the porous plug, which provisions do not require saving action by an operator.
According to the present invention, a second plug of a porous refractory material having a higher permeability than that of the first plug is coaxially nested within and located at the lower end of the sleeve bore; the gas-tight mounting being to the base of the second plug, means being provided to retain the first, upper plug and the second, lower plug in their relative positions in the sleeve bore.
By this means, plug removal is facilitated because the relatively soft plugs and the eroded upper plug can be readily punched out upwards into an empty, but still hot, ladle by a bar or the like inserted through the sleeve bore, the inner end of the bar having a locking member pivoted thereon to turn and lock against the head of the sleeve to enable the remaining components of the plug assembly to be withdrawn by pulling on the bar.
Clearly, such an operation can be conducted by an operator at the cooler rear of the ladle. The second, lower plug permits passage of gas into the ladle but guards against leakage of metal through the upper plug.
In a first embodiment of the invention, a ceramic tube is used to maintain the separation between the two plugs; alternatively, a combustible tube may be used whilst the sleeve is cast about them.
The space between the plugs may be filled with wire wool or refractory aggregate.
In a second embodiment of the invention, the aggregate is coated with a glaze that, should the upper plug fail, would, in the heat of the molten metal as it first enters the sleeve bore, fuse the aggregate to seal the bore and prevent escape of metal. Alternatively, the aggregate could be coated with a chemical agent to promote sintering at temperatures above those of normal operation so that a solid plug would be formed before molten metal could escape.
The invention is illustrated, by way of example, in the Drawing of a cross-section of a porous plug assembly for insertion in a ladle bottom.
As shown, a porous plug assembly consists of a generally frusto-conical plug 1 of a porous refractory material such as fused alumina or maganesite.
The plug is coaxially nested within and is located at the upper end of a bore 2 in a frusto-conical sleeve 3 of a high alumina, castable refractory material. The upper plug 1 tapers from its base 4 to its head 5 that is approximately level with the head 6 of the sleeve 3. The upper plug 1 is considerably shorter than the sleeve 3, this latter component being of substantially the same height as the thickness of the lining 7 of the ladle bottom 8 into which the assembly is to be inserted.
A further, cylindrical plug 9 of a porous material such as fused bauxite or magnesite is located in the lower end of the sleeve bore 2 with its base 10 level with the base 11 of the sleeve; the permeability of the lower plug material being greater than that of the upper plug material.
A metal shell 12 covers the circumferential, outer surface 13 of the sleeve 3 nearly to the head 6 thereof and covers the sleeve and lower plug bases 11 and 12 to make a gas-tight seal therewith.
A pipe 14, to supply a gas such as argon to the installed plug assembly, is shown to be connected to the shell base 15 by an internally-threaded piperunner 16 welded at 17 to the shell base 15 whilst an externally-threaded plug 18 is welded at 19 to the end of the gas pipe 14; providing a demountable connection.
The upper plug 1 is separated from the lower plug 9 by a ceramic tube 20, having a smaller diameter than either plug, and the void within the sleeve bore 2 between the plugs is fitted with steel wool or refractory aggregate 21.
The upper plug 1 is tapered so that gas pressure on its base 4 will only tend to maintain the plug in the sleeve bore. The sleeve 3 is outwardly tapered to fit the ladle nest brick assembly in the ladle bottom.
One method of manufacturing plug assemblies in accordance with the invention is to position a lower plug 9, a separator tube 20 and an upper plug 1 inside a shell 12 and then cast the sleeve 3 about the plugs and tube, using the shell as a mould. The shape of the upper plug serving to key with the cast sleeve, which retains the lower plug against the shell base 15. The tube 20 could be of a combustible material such as cardboard as it has effectively served its plug retaining purpose once the sleeve has been cast.
When the time comes to replace the plug assembly the two plugs, and sleeve bore filling, can readily be punched into an empty, hot ladle using a bar introduced through the gas pipe port 22 in the shell base 15 as they will be significantly softer than the surrounding sleeve; the port is of the same diameter as the lower plug so that this plug and the bore filling could be extracted through the port. The remaining assembly components, namely the sleeve and shell, can be removed from the surrounding brick nest into which the assembly has been mortered by means of a locking member pivoted to the inner end of the bar that, once the bar has been inserted, will swing to lock against the sleeve head 6 to enable the assembly to be pulled from the ladle bottom.
In an embodiment of the invention, the aggregate is either coated with a glaze that will not melt during normal operation of the assembly but which, should the upper plug fail, would fuse the aggregate into a solid plug on first being exposed to molten metal to prevent metal escaping through the assembly; or the aggregate is coated with a chemical sintering agent that, above normal operating temperatures, would sinter the aggregate into a solid safety plug.
Claims (9)
1. A porous plug assembly for a refractory lined vessel for molten metal comprising a plug of porous refractory material that has a height substantially less than that of a vessel bottom lining into which the assembly is to be inserted, the plug being coaxially nested within and located at the upper end of a bore in a non-porous ceramic or other refractory sleeve having a height substantially equal to that of the ladle bottom lining, a second plug of a porous refractory material having a higher permeability than that of the first plug being coaxially nested within and located at the lower end of the sleeve bore; a gas-tight mounting for the second plug base being provided to enable a gas pipe to be connected to the assembly and means are provided to retain the first, upper plug and the second, lower plug in their relative positions in the sleeve bore.
2. An assembly as claimed in claim 1, wherein the upper plug is generally of a frusto-conical shape tapering from its base to its head and is coaxially nested within a complementary bore in the ceramic or other refractory sleeve.
3. An assembly as claimed in claim 1, wherein a separator tube is located in the sleeve bore between the upper and lower plugs to retain them in their relative positions.
4. An assembly as claimed in claim 3, wherein the separator tube is of ceramic or combustible material.
5. An assembly as claimed in any of claims 1 to 4, wherein the pipe mounting is a metal shell covering the bases of the lower plug and sleeve and making a gas-tight seal therewith and extending at least part-way up the outer circumference of the sleeve.
6. An assembly as claimed in claim 5, wherein the sleeve is cast about the upper and lower plugs and the separator tube and within the metal shell.
7. An assembly as claimed in any of the previous claims, wherein the unoccupied space within the sleeve bore is filled with steel wool or refractory aggregate.
8. An assembly as claimed in claim 7, wherein the aggregate is coated with a glaze that will fuse the aggregate on contact with molten metal to form a solid plug to prevent escape of molten metal from the vessel through the plug assembly.
9. An assembly as claimed in claim 7, wherein the aggregate is coated with a chemical agent to promote sintering of the aggregate at above normal operating temperatures to form a solid plug to prevent escape of molten metal from the vessel through the plug assembly.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB838329038A GB8329038D0 (en) | 1983-10-31 | 1983-10-31 | Porous plug assemblies |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8427491D0 GB8427491D0 (en) | 1984-12-05 |
| GB2150868A true GB2150868A (en) | 1985-07-10 |
| GB2150868B GB2150868B (en) | 1986-11-26 |
Family
ID=10550999
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB838329038A Pending GB8329038D0 (en) | 1983-10-31 | 1983-10-31 | Porous plug assemblies |
| GB08427491A Expired GB2150868B (en) | 1983-10-31 | 1984-10-31 | Porous plug assemblies for molten metal vessels e.g. ladles |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB838329038A Pending GB8329038D0 (en) | 1983-10-31 | 1983-10-31 | Porous plug assemblies |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB8329038D0 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2177485A (en) * | 1985-06-28 | 1987-01-21 | Didier Werke Ag | Gas purging device |
| EP0224657A1 (en) * | 1985-12-04 | 1987-06-10 | Didier-Werke Ag | Gas-flushing installation for melt containers |
| GB2194028A (en) * | 1986-07-12 | 1988-02-24 | Didier Werke Ag | Gas purging device |
| WO1988006191A1 (en) * | 1987-02-18 | 1988-08-25 | Injectall Limited | Devices and apparatus for injecting gas into high temperature liquids, e.g. molten metals |
| US4944496A (en) * | 1987-04-10 | 1990-07-31 | Injectall Limited | Apparatus for injecting gas into high temperature liquids, e.g. molten metals |
| US5198179A (en) * | 1989-04-24 | 1993-03-30 | Injectall Limited | Gas injector |
| US5249811A (en) * | 1990-08-16 | 1993-10-05 | Didier-Werke Ag | Refractory joint packing for an annular gap in a metallurgical vessel |
-
1983
- 1983-10-31 GB GB838329038A patent/GB8329038D0/en active Pending
-
1984
- 1984-10-31 GB GB08427491A patent/GB2150868B/en not_active Expired
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2177485A (en) * | 1985-06-28 | 1987-01-21 | Didier Werke Ag | Gas purging device |
| EP0224657A1 (en) * | 1985-12-04 | 1987-06-10 | Didier-Werke Ag | Gas-flushing installation for melt containers |
| GB2194028A (en) * | 1986-07-12 | 1988-02-24 | Didier Werke Ag | Gas purging device |
| US4779849A (en) * | 1986-07-12 | 1988-10-25 | Didier-Werke Ag | Gas washing device with reduced gas flow upon wear of gas sink |
| GB2194028B (en) * | 1986-07-12 | 1990-04-18 | Didier Werke Ag | Gas purging device |
| WO1988006191A1 (en) * | 1987-02-18 | 1988-08-25 | Injectall Limited | Devices and apparatus for injecting gas into high temperature liquids, e.g. molten metals |
| EP0281267A1 (en) * | 1987-02-18 | 1988-09-07 | Injectall Limited | Devices and apparatus for injecting gas into high temperature liquids, E.G. molten metals |
| US4899992A (en) * | 1987-02-18 | 1990-02-13 | Injectall Limited | Devices and apparatus for injecting gas into high temperature liquids, e.g. molten metals |
| US4944496A (en) * | 1987-04-10 | 1990-07-31 | Injectall Limited | Apparatus for injecting gas into high temperature liquids, e.g. molten metals |
| US5198179A (en) * | 1989-04-24 | 1993-03-30 | Injectall Limited | Gas injector |
| US5249811A (en) * | 1990-08-16 | 1993-10-05 | Didier-Werke Ag | Refractory joint packing for an annular gap in a metallurgical vessel |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2150868B (en) | 1986-11-26 |
| GB8329038D0 (en) | 1983-11-30 |
| GB8427491D0 (en) | 1984-12-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |