Filtration device

• US 5,511,766 A
• Filed: 09/28/1994
• Issued: 04/30/1996
• Est. Priority Date: 02/02/1993
• Status: Expired due to Fees

• Current Assignee: USX Corporation
• Original Assignee: USX Corporation
• Inventors: Vassilicos, Achilles
• Primary Examiner(s): ANDREWS, MELVYN J
• Application Number:
  US08/313,944
• Time in Patent Office: 580 Days
• Field of Search: 266/78, 266/227, 75/407, 75/387
• US Class Current: 266/78
• CPC Class Codes: B22D 11/11 Treating the molten metal
• CPC Class Codes: B22D 11/119 by filtering
• CPC Class Codes: C22B 9/023 By filtering filtration of aluminium C22B21/066
• CPC Class Codes: Y02P 10/20 Recycling

Abstract

A vessel used for transfer of molten metal having a refractory filter wall with filters for removing inclusion from molten metal as it flows through the vessel. The refractory filter wall having passages sized according to a predetermined volume of molten metal that is to be filtered, the desired flow rate of molten metal through the vessel and the limiting characteristics of the filters. In another aspect of the invention, protrusions are provided on refractory walls of the vessel to enhance deposition of non-metallic inclusions on the protrusions by disrupting the boundary layer flow in the molten metal.

Claims

1. A tundish for use with molten metal comprising:

a container having refractory bottom and a plurality of refractory side walls forming a cavity for holding and directing the flow of molten metal therein;

at least one refractory filter wall extending completely across the cavity to opposed refractory side walls of the container, said refractory filter wall being of essentially the same height as the refractory side walls and extending transverse to the direction of molten metal flow so as to divide said cavity into at least one upstream chamber and at least one downstream chamber;

said refractory filter wall having filter means for removing inclusions from said molten metal as the molten metal flows from the upstream chamber through the filter means to the downstream chamber, said filter means having an initial flow resistance coefficient that is a design characteristic of said filter means;

said container having at least one passage for permitting unfiltered flow of a portion of the molten metal from the upstream chamber to the downstream chamber, said passage having a cross sectional area greater than 0.75 square inches, said cross sectional area of the passage being selected based upon said initial flow resistance coefficient of the filter means so as to accomplish a desired initial distribution of the volume of flow of molten metal through said filter means with respect to the volume of flow through said opening.

2. A tundish according to claim 1 wherein said filter means comprises a plurality of openings each with a cross sectional area less than 0.75 square inches.

3. A tundish according to the claim 1 wherein said filter means comprises at least one porous ceramic filter element mounted in said refractory filter wall.

4. A tundish according to claim 1 wherein the initial ratio of the total cross section area of said passage for permitting unfiltered flow to the initial total open cross section area of said filter means does not exceed 1.0.

5. A tundish according to claim 1 wherein said passage for permitting unfiltered flow of molten metal is located in said refractory filter wall.

6. A tundish according to claim 1 further comprising a flow control device for regulating volume of molten metal through said passage for permitting unfiltered flow so as to adjust the distribution of flow of molten metal through the filter means and the unfiltered flow thereof.

7. A molten metal filtration apparatus for use in a tundish, comprising:

at least one refractory filter wall for extending completely across a cavity in the tundish in a direction transverse to a direction of molten metal flow therein so as to divide said tundish cavity into at least one upstream chamber and at least one downstream chamber;

said refractory filter wall having filter means therein for removing inclusions from said molten metal as the molten metal flows through said filter means, said filter means having an initial flow resistance coefficient that is a design characteristic thereof;

said refractory filter wall having at least one opening forming a passage through said refractory filter wall for permitting unfiltered flow of a portion of the molten metal from the upstream chamber to the downstream chamber of the tundish cavity, said opening having a cross sectional area greater than 0.75 square inches, said cross sectional area of the opening being selected based upon said initial flow resistance coefficient so as to accomplish a desired initial distribution of the volume of flow of said molten metal through said filter means with respect to the volume of flow through said opening.

8. A molten metal filtration apparatus according to claim 7 wherein said filter means comprises a plurality of openings each with a cross sectional area less than 0.75 square inches.

9. A molten metal filtration apparatus according to claim 7 wherein said filter means comprises at least one porous ceramic filter element mounted in said refractory filter wall.

10. A molten metal filtration apparatus according to claim 7 wherein the initial ratio of the total cross section area of said opening forming a passage for unfiltered flow to the initial total open cross section area of the filter means does not exceed 1.0.

11. A molten metal filtration apparatus according to claim 7 further comprising a flow control device for regulating volume of molten metal through said passage for permitting unfiltered flow so as to adjust the distribution of flow of molten metal through the filter means and the unfiltered flow thereof.