Rotary degasser

• US 5,678,807 A
• Filed: 06/13/1995
• Issued: 10/21/1997
• Est. Priority Date: 06/13/1995
• Status: Expired due to Term

• Current Assignee: Molten Metal Equipment Innovations Incorporated (Molten)
• Original Assignee: Paul V. Cooper
• Inventors: Cooper, Paul V.
• Primary Examiner(s): KASTLER, SCOTT R
• Application Number:
  US08/489,962
• Time in Patent Office: 861 Days
• Field of Search: 266/216, 266/217, 266/233, 266/235
• US Class Current: 266/216
• CPC Class Codes: C22B 21/064 using inert or reactive gases C22B21/066 and C22B21/068 take precedence
• CPC Class Codes: C22B 9/05 Refining by treating with gases, e.g. gas flushing also refining by means of a material generating gas in situ
• CPC Class Codes: F27D 27/00 Stirring devices for molten material F27D3/14 takes precedence

Abstract

A rotary degasser for removing impurities from molten metal is disclosed that includes a degasser shaft, an impeller block and a coupling. The shaft is preferably hollow to allow for the passage of gas therethrough. The impeller block is connected to the degasser shaft, is formed of heat resistant material and has at least one metal-transfer recess, which displaces molten metal when the block is rotated. The block preferably includes at least one gas inlet in communication with the hollow portion of the degasser shaft and a gas-release opening formed in each metal-transfer recess. Each gas-release opening communicates with one of the gas inlets. The coupling connects the degasser shaft to a drive shaft and is formed of two or more coupling members. The coupling has a closed position in which it retains the degasser shaft and an open position in which it does not retain the degasser shaft. The coupling also includes a retainer that is connected to one of the coupling members and an adjustment device connected to the retainer. The adjustment device has a first position in which the coupling is retained in its closed position and a second position in which the coupling is not retained in its closed position and can be moved to its open position.

Claims

1. A device for introducing gas into molten metal, said device including:

a) a degasser shaft, said shaft comprising a gas-transfer conduit;

b) an impeller block connected to said degasser shaft, said impeller block having a gas inlet communicating with said gas-transfer conduit and at least one metal-transfer recess formed therein;

c) at least one gas-release opening formed in each of said recesses; and

d) a coupling connected to said degasser shaft;

whereby said device is positioned in a molten metal bath and said degasser shaft is connected to a drive source by said coupling;

the drive source turns the degasser shaft and the impeller block, the impeller block thereby displacing the molten metal substantially entirely radially and simultaneously, gas is introduced into said conduit whereby it passes into the gas inlet and out of the gas-release opening(s) where it is sheared by the molten metal being displaced by the recess.

2. A device as defined in claim 1 wherein said impeller block is comprised of graphite.

3. A device as defined in claim 1 wherein said impeller block has two ends and a metal-transfer recess formed at each end.

4. A device as defined in claim 1 wherein said impeller block is threadingly received onto said degasser shaft.

5. A device as defined in claim 2 wherein said block is generally rectangular.

6. An impeller block for dispersing gas into molten metal, said block formed of heat resistant material, said block comprising at least one gas inlet, at least one metal-transfer recess and at least one gas-transfer opening formed in said recess, and in communication with said gas inlet, said block connectable to a degasser shaft whereby said shaft turns said block thereby substantially entirely radially displacing the molten metal and gas is introduced into said gas inlet and passes out of said gas-transfer opening where it is sheared by the molten metal being displaced by the recess.

7. An impeller block as described in claim 6 which further includes at least one gas-inlet and at least one gas-release opening in each metal-transfer recess, said at least one gas-release opening being in communication with said at least one gas inlet.

8. An impeller block for dispersing gas into molten metal, said block formed of heat resistant material, said block comprising at least one metal-transfer recess, as defined in claim 6 which further includes a bottom surface and an opening in said bottom surface, whereby said block is connectable to a degasser shaft that turns said block thereby substantially entirely radially displacing the molten metal and gas or flux is released through said opening where it travels into said recess and is sheared by the molten metal entering said recess.

9. An impeller block as defined in claim 8 which further includes a one or more channels in said bottom, said channels directing the gas released through said opening.

10. A device as defined in claim 6 wherein said at least one metal-transfer recess is at least 10% of the length of said block.

11. A device as defined in claim 6 wherein said at least one metal-transfer recess is at least 25% as wide as said block.

12. A device as defined in claim 11 wherein said at least one metal-transfer recess is at least 25% the depth of said block.

13. A device as defined in claim 6 wherein said block is at least 6" in length.

14. A coupling for connecting a hollow degasser shaft to a drive device, said coupling comprising an annular flange with an inner surface defining an opening and a generally cylindrical collar connected to, and extending perpendicularly from said annular flange;

said collar comprising at least a first coupling member and a second coupling member and said annular flange comprising at least a first flange section connected to the first coupling member, and a second flange section connected to the second member;

said coupling device further comprising a retainer and an adjustment device, said retainer being connected to said retainer and having a first position wherein said coupling is in a closed position, and is able to retain the hollow degasser shaft within said opening, and said adjustment device having a second position wherein said coupling is not retained in a closed position and can be moved to an open position, where the hollow degasser shaft is not retained within said opening.

15. A coupling as defined in claim 14 wherein said adjustment device is in contact with said second coupling member when said adjustment device is in said second position.

16. A coupling as defined in claim 14 wherein said retainer surrounds said second coupling member.

17. A coupling as defined in claim 14 wherein said adjustment device is a bolt threadingly received in said retainer.

18. A device for introducing gas into molten metal, said device including:

a) a degasser shaft, said degasser shaft comprising a gas-transfer conduit;

b) an impeller block connected to said degasser shaft, said impeller block having a gas inlet communicating with said gas-transfer conduit and at least one metal-transfer recess formed therein; and

c) at least one gas-release opening formed in each of said recesses;

whereby said device is positioned in a molten metal bath and said degasser shaft is connected to a drive source by said coupling;

the motor turns the degasser shaft and the impeller block, the impeller block thereby displacing the molten metal substantially entirely radially and simultaneously, gas is introduced into said conduit whereby it passes into the gas inlet and out of the gas-release opening into the molten metal being displaced by the recess.

19. In combination, a degasser shaft connected to a coupling for connecting a hollow degasser shaft to a drive device, said coupling comprising an annular flange with an inner surface defining an opening, and a generally cylindrical collar connected to, and extending perpendicularly from said annular flange;

said collar comprising at least a first coupling member and a second coupling member and said annular flange comprising at least a first flange section connected to the first coupling member, and a second flange section connected to the second coupling member;

said coupling device further comprising a retainer and an adjustment device, said retainer being connected to said first coupling member, said adjustment device being connected to said retainer and having a first position wherein said coupling is in a closed position, and is able to retain the hollow degasser shaft within said opening, and said adjustment device having a second position wherein it does not contact said second coupling member and said coupling can be moved to an open position where the hollow degasser shaft is not retained within said opening.