PROCESS AND SYSTEM FOR PUMPING MOLTEN METAL

• US 3,759,635 A
• Filed: 03/16/1972
• Issued: 09/18/1973
• Est. Priority Date: 03/16/1972
• Status: Expired due to Term

• Current Assignee: Donald C. Kush, Melvin A. Carter, Theodore D. Steinke
• Original Assignee: Donald C. Kush, Melvin A. Carter, Theodore D. Steinke
• Inventors: Carter, Melvin A., Steinke, Theodore D., Kush, Donald C.
• Primary Examiner(s): Freeh, William L.
• Assistant Examiner(s): Winburn, John T.
• Application Number:
  US05/235,441
• Time in Patent Office: 551 Days
• Field of Search: 266/38 310/11,86,87 417/50,53
• US Class Current: 417/50
• CPC Class Codes: H02K 44/06 Induction pumps

Abstract

This invention relates to an electromagnetic pumping system for molten metal which comprises a device for generating a rotating, helically shaped electromagnetic field which induces downwardly directed molten metal flow in the annular space defined by two concentric upstanding cylindrical surfaces. A preferred embodiment of the invention relates to a process and system for pumping molten metal, wherein one discharge conduit recycles molten metal to a chamber at a predetermined flow rate and when the recycling is completed, the flow rate is substantially increased, thereby pumping metal to a second chamber without increasing substantially the molten metal flow to said first container.

Claims

1. A molten metal pumping system comprising a. an upstanding inner member formed of molten metal resistive material having a substantially cylindrical outer surface which is supported in the vertical direction on the bottom portion of said member by a support surface, b. an outer member formed of molten metal resistive material having a substantially cylindrical inner surface concentric with the outer surface of said inner member and defining an annular space therebetween, said outer member being supported on the bottom portion thereof by said support surface and thereby closing the lower end of said annular space, c. a feed trough attached to the upper portion of said outer member, said trough adapted to feed molten metal to said annular space and said trough in fluid communication with a container, d. at least a first discharge conduit attached to the lower portion of said outer member, said first conduit in fluid communication with said annular space and with a container, e. a circumferentially extending flux return path means associated with said outer member, and f. means within said inner member to generate a rotating, helically shaped electromagnetic field resulting in molten metal flow in a downward direction in said annular space.

2. The pumping system of claim 1 in which the means to generate a rotating, helically shaped electromagnetic field comprises a magnetic, cylindrically shaped body having a plurality of helically shaped grooves in the periphery thereof forming a pluralitY of poles, and an electrical conductor wrapped at least one time around each of said poles to form field windings, said field windings adapted to be electrically connected to a direct current source whereby adjacent poles have opposite polarity.

3. The molten metal pumping system of claim 1 in which at least one discharge conduit is oriented with said outer member to provide for substantially tangential molten metal flow.

4. The pumping system of claim 1 wherein said concentric surfaces of said inner and outer members are spaced apart from about 1-3 inches.

5. The pumping system of claim 1 wherein means are provided to press said inner member against said support plate.

6. The pumping system of claim 1 wherein said inner member, outer member, feed trough and support plate are formed of a refractory material selected from the group consisting of silicon nitride bonded silicon carbide and silicon oxynitride bonded silicon carbide.

7. The pumping system of claim 6 wherein said inner member, outer member, feed trough and support plate are joined in a unitary piece.

8. The molten metal pumping system of claim 1 wherein at least a second discharge conduit is attached to the lower portion of said outer member and is in fluid communication with said annular space defined by said inner and outer members, the cross section of one of said conduits being substantially greater than said other discharge conduit, said conduit having the greater cross section extending above the molten metal level in said feed trough and in fluid communication with a first container and adapted to discharge molten metal therein and said conduit having the lesser cross section in fluid communication with a second container and adapted to discharge molten metal therein.

9. The molten metal pumping system of claim 8 wherein said conduit having the greater cross section is provided with a discharge conduit, said discharge conduit in fluid communication with the feed trough to thereby recycle molten metal to the feed trough and maintain metal in said conduit having the greater cross section in a molten state.

10. The molten metal pumping system of claim 8 in which said discharge conduit having the smaller cross section is in fluid communication with the container with which the feed trough is in fluid communication.

11. A process of transporting molten metal comprising a. withdrawing molten metal from a first container, b. feeding said molten metal to the upper portion of an annular space defined by two upstanding members through a feeding trough attached to the outermost member, c. inducing substantial downward molten metal flow within said annular space by generating a rotating, helically shaped electromagnetic field of a predetermined magnitude, d. directing said downwardly moving metal in said annular space to two conduit means, a first conduit means having a cross-sectional area substantially greater than the second conduit means and having at least one discharge opening above the level of the molten metal being fed to said annular space, and e. discharging at least substantially all of said downwardly moving molten metal from said smaller conduit into said first container.

12. The process of claim 11 wherein at least a portion of the metal in said first conduit means is returned to the feed trough from a second discharge opening in said first conduit positioned below said first discharge opening above the molten metal level in said feed trough, thereby maintaining the metal in said first conduit means in a substantially molten state.

13. The process of transporting molten metal of claim 11 wherein a. the magnitude of the electromagnetic field is increased to substantially increase the molten metal flow in a downward direction, and b. discharging at least a portion of said molten metal in said first conduit through a discharge opening into a second container.

14. The process of claim 11 wherein a. the rotational speed of the helically shaped electromagnetic field is increased to increase the molten metal flow in a downward direction, and b. discharging at least a portion of said molten metal in said first conduit through a discharge opening into a second container.

15. The process of claim 11 wherein said rotating helically shaped electromagnetic field is generated by rotating a substantially cylindrical shaped magnetic body having a plurality of helically shaped grooves on the periphery thereof forming a plurality of poles, and having a conductor wrapped at least one time around each of said poles, said conductor electrically connected to a direct current source.

16. A process of preparing and transporting a homogeneous melt of molten metal comprising a. providing a supply of molten metal in a first chamber, b. withdrawing molten metal from said first chamber, c. feeding said molten metal to the upper portion of an annular space defined by two upstanding refractory members through a feeding trough attached to the outermost upstanding member, d. inducing downward molten metal flow within said annular space by generating a rotating helically shaped electromagnetic field of a predetermined magnitude, e. directing said downwardly moving molten metal in said annular space to two conduits, a first conduit having a cross-sectional area substantially greater than the second conduit, said first conduit extending above and having at least one discharge opening above the level of molten metal in said feed trough, f. discharging substantially all of said downwardly moving molten metal from said second conduit into said first chamber until a melt of the desired homogenuity is obtained in said first chamber, g. increasing the magnitude of the rotating helically shaped electromagnetic field, thereby sufficiently increasing the molten metal flow through said annular space to discharge molten metal from the discharge opening in said first conduit, h. discharging molten metal from said discharge opening in said first conduit to a second chamber until a desired amount of molten metal is transported into said second chamber, and i. decreasing the magnitude of the electromagnetic field to thereby cease molten metal flow to said second chamber.

17. The process of claim 16 wherein molten metal is returned from said first feed conduit to the feed trough.

18. The process of claim 16 wherein the molten metal is aluminum.