ROTARY DEGASSERS AND COMPONENTS THEREFOR

• US 20110163486A1
• Filed: 09/09/2010
• Published: 07/07/2011
• Est. Priority Date: 08/07/2009
• Status: Active Grant

• Current Assignee: Molten Metal Equipment Innovations Incorporated (Molten)
• Original Assignee: Molten Metal Equipment Innovations Incorporated (Molten)
• Inventors: Cooper, Paul V.
• Granted Patent: US 8,524,146 B2
• Time in Patent Office: Days
• US Class Current: 266/217
• CPC Class Codes: C21C 1/06 Constructional features of mixers for pig-iron
• CPC Class Codes: F01D 5/18 Hollow blades, i.e. blades with cooling or heating channels or cavities structure of hollow blades in general F01D5/147; Heating, heat-insulating or cooling means on blades
• CPC Class Codes: F16C 3/02 Shafts; Axles
• CPC Class Codes: F16D 1/108 having retaining means rotating with the coupling and acting by interengaging parts, i.e. positive coupling
• CPC Class Codes: F27B 3/22 Arrangements of air or gas supply devices
• CPC Class Codes: F27D 2027/002 Gas stirring
• CPC Class Codes: F27D 27/00 Stirring devices for molten material F27D3/14 takes precedence
• CPC Class Codes: F27D 3/16 Introducing a fluid jet or current into the charge porous elements for gas flushing of molten metals B22D1/005

Abstract

Disclosed are degassers, couplings, impeller shafts and impellers for use in molten metal. One such coupling transfers gas into an impeller shaft, the coupling having a smooth, tapered internal surface to align with a corresponding surface on the impeller shaft and help prevent gas leakage and to assist in preventing damage to the impeller shaft. Improved impellers for shearing and mixing gas are also disclosed, as is a degasser including one or more of these components.

Claims

1. A rotary degas ser for introducing gas into molten metal, the rotary degas ser comprising:

an impeller shaft, the impeller shaft comprising a gas-transfer conduit and having a first end that is not threaded and a second end;

a coupling coupled to the first end of the impeller shaft and including at least one retainer to retain the first end of the impeller shaft;

an impeller connected to the second end of the impeller shaft, wherein the impeller comprises;

at least one impeller opening communicating with the gas-transfer conduit;

at least one channel juxtaposed the opening;

at least one cavity; and

wherein the at least one channel guides gas exiting the opening to the at least one cavity of the impeller.

2. The rotary degasser of claim 1 that further includes a drive source.

3. The rotary degasser of claim 2, wherein the drive source is a pneumatic motor.

4. The rotary degasser of claim 2, wherein the device further includes a drive shaft, the drive shaft comprising the impeller shaft coupled to a motor shaft by the coupling.

5. The rotary degasser of claim 1 that further includes a gas source.

6. The rotary degasser of claim 5, that further includes a motor shaft and the gas source introduces gas into the motor shaft.

7. The rotary degasser as defined in claim 1, wherein the cavity comprises a top surface and at least one curved impeller side surface and at least one of the channels is in communication with the curved impeller side surface.

8. The rotary degasser of claim 1, wherein the impeller has a top surface, a bottom surface and one or more cavities, wherein each cavity is defined by a curved side surface and a top surface.

9. The rotary degasser of claim 8, wherein the top surface has an outer perimeter and at least part of each of the one or more curved side surfaces is inside the outer perimeter of the top surface.

10. The rotary degasser of claim 9 that has four cavities.

11. The rotary degasser of claim 10 that has four channels and each channel leads to the center of one respective curved side surface.

12. The rotary degasser as defined in claim 1, wherein each cavity is juxtaposed a shearing structure.

14. The rotary degasser as defined in claim 1, wherein the impeller is comprised of graphite.

15. The rotary degasser as defined in claim 1, wherein the impeller is threadingly received onto the second end of the impeller shaft.

16. The rotary degasser as defined in claim 1, wherein the retainer is at least one set screw.

17. The rotary degasser as defined in claim 1, wherein the coupling comprises a tapered interior surface for receiving the impeller shaft.

18. The rotary degasser as defined in claim 1, wherein the impeller shaft comprises at least one groove for receiving one or more retainers.

13. The rotary degasser of claim 13, wherein each shearing structure is an edge of a curved surface that partially forms the cavity.

19. An impeller having a top surface and a bottom surface, the impeller for dispersing gas into molten metal and comprising:

an opening in the bottom surface through which gas can be released;

at least one channel in communication with the opening, the channel for directing the gas; and

at least one cavity, the channel directing gas to the cavity.

20. The impeller as defined in claim 19, further comprising a plurality of cavities and a plurality of channels, wherein each of the plurality of channels leads to one of the cavities.

21. The impeller as defined in claim 19, wherein the cavity is defined by a curved side surface and a top surface and the channel extends from the center of the impeller to the center of the curved side surface.

22. The impeller as defined in claim 21, comprising four channels, wherein each channel extends from a center of the impeller to a cavity.

23. The impeller as defined in claim 19 that further includes a shearing structure juxtaposed the cavity.

24. The impeller as defined in claim 19, wherein the impeller is comprised of graphite.

25. A coupling configured for an impeller shaft, the coupling comprising:

a passage through which gas can be transferred;

an inner surface defining a tapered opening and having no threads; and

one or more openings for receiving a retainer.

26. The coupling as defined in claim 25, wherein the retainer is a set screw.

27. The coupling as defined in claim 25, that is comprised of steel.

28. The coupling as defined in claim 27, wherein the interior surface has a cylindrical inner surface beneath the tapered portion.

29. The coupling as defined in claim 25, wherein the coupling comprises a plurality of openings, each of the openings for receiving a retainer.

30. An impeller shaft for use in a rotary degasser, the impeller shaft having a first end for being received by a coupling and a second end for connecting to an impeller, the first end having no threads for being threadingly received in the coupling, and having a smooth, tapered portion, and including at least one groove for being retained by a retainer.

31. The impeller shaft of claim 30 that has one, helical groove.

32. The impeller shaft of claim 31, wherein the groove is not on the smooth, tapered portion.

33. The impeller shaft of claim 30 that is comprised of graphite.

34. An impeller for use in a rotary degasser, the impeller comprising:

an opening through which gas can escape;

a first cavity for capturing gas released form the opening; and

a second cavity above the first cavity, the second cavity for capturing gas released from the gas-release opening.

35. The impeller of claim 34 wherein there are a plurality of first cavities and a plurality of second cavities.

36. The impeller of claim 35, wherein each of the plurality of first cavities is juxtaposed by a shearing structure.

37. The impeller of claim 35, wherein each of the plurality of second cavities is juxtaposed by a shearing structure.

38. The impeller of claim 36, wherein each of the plurality of second cavities is juxtaposed by a shearing structure.

39. The impeller of claim 35, wherein there are eight first cavities and four second cavities.