Overflow transfer furnace and control system for reduced oxygen production in a casting furnace

• US 20030201583A1
• Filed: 04/25/2002
• Published: 10/30/2003
• Est. Priority Date: 04/25/2002
• Status: Active Grant

• Current Assignee: Shipston Aluminum Technologies (Indiana), Inc. (Shipston Aluminum Technologies International, Inc.)
• Original Assignee: Alcoa Incorporated (Howmet Aerospace, Inc.)
• Inventors: Klingensmith, Marshall A., Borns, Rick A., Kinosz, Michael J.
• Granted Patent: US 6,902,696 B2
• Time in Patent Office: Days
• US Class Current: 266/94
• CPC Class Codes: C22B 21/0084 melting and handling molten aluminium C22B21/02, C22B21/04 and C22B21/06 take precedence

Abstract

An apparatus for transferring molten metal from a melting furnace to a casting furnace is provided. A sensing and control system for the transfer of molten metal from a transfer furnace to a casting furnace is also described. The combination of the transfer apparatus with the sensing and control system provides for the introduction of reduced oxide molten metal into a casting furnace.

Claims

1. An apparatus for supplying molten metal to a casting furnace, the apparatus comprising:

(a) a plurality of chambers;

(b) at least one connection between the chambers that allows for the transfer of molten metal between the chambers; and

(c) an outlet from one of the plurality of chambers, said outlet being connected to a casting furnace, arranged to accept an over-flow of molten metal from the chamber such that said over-flow of molten metal can be discharged into the casting furnace, and comprised of a trough and a downspout.

2. The apparatus of claim 1, wherein the molten metal is aluminum.

3. The apparatus of claim 1, wherein the over-flow of molten metal that is discharged into the casting furnace is transferred substantially without contacting the atmosphere.

4. The apparatus of claim 1, further comprising a pump for the transfer of molten metal from an upstream chamber to a downstream chamber.

5. The apparatus of claim 3, wherein said pump is a variable speed centripetal pump.

6. The apparatus of claim 4, further comprising a control arrangement, said control arrangement being functional to vary the rate of speed of said pump to thereby control the over-flow of molten metal to the casting furnace.

7. The apparatus of claim 4, further comprising a sensing system to sense downstream parameters.

8. The apparatus of claim 7, wherein said sensing system comprises an outlet sensor adapted to detect the presence of molten metal in said outlet.

9. The apparatus of claim 8, wherein said outlet sensor is adapted to measure the level of molten metal present in said outlet.

10. The apparatus of claim 4, further comprising a recirculation conduit that allows molten metal to flow from the downstream chamber to the upstream chamber.

11. The apparatus of claim 1, wherein said trough is connected to said downspout such that molten metal from the trough flows into the downspout and exits the downspout below a surface of molten metal previously discharged into the casting furnace.

12. The apparatus of claim 6, wherein said pump is responsive to a signal initiated by said sensing system.

13. An apparatus for the introduction of molten metal to a casting furnace comprising:

(a) an upstream chamber for holding molten metal;

(b) a downstream chamber for holding molten metal;

(c) a wall substantially separating the upstream chamber from the downstream chamber;

(d) a pump disposed within an opening in the wall, said pump adapted to raise the level of molten metal in the downstream chamber above the level of metal in the upstream chamber; and

(e) an outlet trough connected to the downstream chamber.

14. The apparatus of claim 13, wherein said pump raises the level of molten metal in the downstream chamber to a level wherein the molten metal over-flows the downstream chamber.

15. The apparatus of claim 14, wherein said pump operates to over-flow molten metal in the downstream chamber in response to a signal received from level sensor located in a casting furnace.

16. An apparatus for the introduction of molten metal to a casting furnace comprising:

(a) an upstream chamber for holding molten metal;

(b) a downstream chamber for holding molten metal;

(c) a sensor adapted to measure the level of molten metal in a trough connecting the downstream chamber to the casting furnace, said sensor being capable of generating a prompt representing the level; and

(d) a pump adapted to transfer molten metal from the upstream chamber to the downstream chamber, wherein said pump is adapted to be responsive to said prompt.

17. A sensing and control system for facilitating the transfer of molten metal to a casting furnace comprising:

(a) a first level sensor located adjacent the casting furnace, said first sensor operably connected to a controller that controls the transfer of molten metal from a source of molten metal to the casting furnace.

18. The sensing and control system of claim 17 further comprising:

(a) a trough located between said source of molten metal and the casting furnace; and

(b) a second level sensor located adjacent said trough, said second sensor operably connected to said controller.

19. The sensing and control system of claim 18 wherein said controller comprises a pump.

20. The sensing and control system of claim 19 wherein said pump is selected from the group consisting of a Holmsley pump, a Lindberg pump and a centripetal pump.

21. The sensing and control system of claim 17 wherein the transfer of molten metal occurs in response to the controller causing an overflow of molten metal from its source, said overflow being initiated by a signal from the first sensor.

22. The sensing and control system of claim 18 wherein said second sensor and said first sensor work independently of one another.

23. A method of transferring molten aluminum from a melting furnace to a casting furnace, the steps comprising:

(a) supplying molten aluminum to a transfer furnace; and

(b) overflowing the transfer furnace such that the molten aluminum flows through a trough and downspout into a casting furnace.

24. The method of claim 23 wherein the molten aluminum is supplied to an upstream chamber of the transfer furnace and subsequently pumped into a downstream chamber of the transfer furnace such that the pumping causes the overflow of molten aluminum from the downstream chamber into the casting furnace.

25. The method of claim 23 wherein the flow of molten aluminum into the casting furnace occurs substantially without contacting the atmosphere.

26. The method of claim 23 further comprising the step of recirculating molten aluminum in the transfer furnace.