INTEGRATED QUIESCENT PROCESSING OF MELTS

• US 20100116453A1
• Filed: 10/13/2009
• Published: 05/13/2010
• Est. Priority Date: 02/23/2007
• Status: Active Grant

• Current Assignee: Alotech, Ltd.
• Original Assignee: Alotech, Ltd.
• Inventors: Campbell, John, Grassi, John R., Shaw, Christopher
• Granted Patent: US 8,303,890 B2
• Time in Patent Office: Days
• US Class Current: 164/63
• CPC Class Codes: B22D 18/06 Vacuum casting, i.e. making use of vacuum to fill the mould
• CPC Class Codes: C21C 5/567 operating in a continuous way
• CPC Class Codes: C22B 21/0084 melting and handling molten aluminium C22B21/02, C22B21/04 and C22B21/06 take precedence
• CPC Class Codes: C22B 21/06 refining electrolytic refining C25C; C22B21/0046, C22B21/0061 take precedence
• CPC Class Codes: C22B 9/006 with use of an inert protective material including the use of an inert gas
• CPC Class Codes: C22B 9/023 By filtering filtration of aluminium C22B21/066
• CPC Class Codes: F27B 3/045 Multiple chambers, e.g. one of which is used for charging
• CPC Class Codes: F27D 3/145 Runners therefor
• CPC Class Codes: Y02P 10/20 Recycling

Abstract

A quiescent melt handling system includes a melting furnace and a holding furnace communicating with the melting furnace for holding a molten metal melt. The holding furnace has a relatively large surface area and a relatively shallow depth, having a width to depth ratio in the range of 4-100 to 1. Also provided is structure in the holding furnace for separating inclusions from the melt in the holding furnace. A mold communicates with the holding furnace. A counter gravity casting system, which might comprise a vacuum assisted casting system, draws the melt into the mold.

Claims

1. A quiescent melt handling system comprising:

a melting furnace;

a holding furnace communicating with said melting furnace, said holding furnace containing a molten metal, wherein said holding furnace comprises a relatively large surface area and a relatively shallow depth having a width to depth ratio in the range of 4-100 to 1;

a means for separating inclusions from the melt in said holding furnace;

a mold communicating with said holding furnace; and

,

a vacuum assisted casting system for said mold to draw the melt from said holding furnace into said mold.

2. The system of claim 1 further comprising:

a conduit communicating said holding furnace with said mold; and

a heating element disposed adjacent said conduit for transferring heat thereto.

3. The system of claim 1 wherein said melting furnace comprises a dry hearth furnace, including a sloping hearth.

4. The system of claim 1 further comprising a means for replenishing a dry atmosphere in said holding furnace, wherein said holding furnace allows hydrogen in the melt to equilibrate with the dry atmosphere being replenished into said holding furnace.

5. The system of claim 4 wherein the means for replenishing comprises a gas inlet located adjacent an outlet of said holding furnace so that a counter current flow of the dry atmosphere takes place.

6. The system of claim 3 wherein said holding furnace further comprises a dry heating means.

7. The system of claim 3 wherein said holding furnace has a length in the range of 1 to 200 meters and wherein a length to width ratio is in the range of 1-100 to 1.

8. The system of claim 1 wherein said means for separating inclusions comprises at least one of a filter and a flow obstructing device.

9. A quiescent melt handling system comprising:

a melting furnace for producing a molten metal melt;

a holding furnace communicating with the melting furnace for holding the molten metal melt, wherein said holding furnace comprises a relatively large surface area and a relatively shallow depth such that a width of said holding furnace in relation to a depth of said holding furnace has a ratio in the range of 4-100 to 1 in order to minimize convection in the melt in said holding furnace; and

a counter-gravity casting system communicates with said holding furnace and urges the melt to flow from said holding furnace into a mold.

10. The system of claim 9 further comprising:

a conduit connecting said holding furnace with said mold; and

,

a heating element disposed adjacent said conduit for transferring heat thereto.

11. The system of claim 10 wherein said conduit comprises:

a first section located adjacent said holding furnace;

a second section located adjacent said mold and spaced from said first section; and

a gasket disposed between said first and second sections.

12. The system of claim 10 further comprising a linear motor disposed around a portion of said conduit.

13. The system of claim 9 wherein said melting furnace comprises a dry hearth furnace, including a sloping hearth.

14. The system of claim 9 wherein said holding furnace further comprises a dry heating means.

15. The system of claim 9 wherein said holding furnace has a length in the range of 1 to 200 meters and wherein a length to width ratio of said holding furnace is in the range of 1-100 to 1.

16. The system of claim 9 wherein said means for separating inclusions comprises at least one of a filter and a flow obstructing device.

17. The system of claim 9 further comprising a means for replenishing a dry atmosphere in said holding furnace, wherein said holding furnace allows hydrogen in the melt to equilibrate with the dry atmosphere being replenished into said holding furnace, wherein the means for replenishing comprises a gas inlet located adjacent an outlet of said holding furnace so that a counter current flow of the dry atmosphere takes place.

18. The system of claim 9 wherein said counter gravity casting system comprises a vacuum assisted casting system.

19. The system of claim 18 wherein said vacuum assisted casting system comprises:

a base plate;

a cover supported by said base plate and defining a chamber therebetween;

an opening in said cover; and

a suction source in communication with said cover opening in order to draw a partial vacuum in said chamber.

20. The system of claim 19 further comprising an opening in said base plate communicating with a conduit, said conduit communicating with a suction source in order to draw a partial vacuum in said opening.

21. A method of quiescent melt handling comprising:

melting a metal in a melting furnace to produce a melt;

flowing the melt into a shallow holding furnace;

providing a substantially unvarying horizontal level of melt in the melting furnace and the holding furnace;

allowing oxide films in suspension in the melt to settle out in the holding furnace via gravity;

flowing the melt from the holding furnace, via a casting station, to a mold.

22. The method of claim 21, wherein the flowing of the melt from the holding furnace to the mold comprises drawing the melt from the holding furnace into the mold via a vacuum assist.

23. The method of claim 21, further comprising:

providing a conduit which communicates the holding furnace with the casting station and the mold; and

drawing a partial vacuum on an outer periphery of a distal end of the conduit, adjacent the mold.