Molten metal degassing device and impellers therefor
First Claim
1. A device for releasing gas into molten metal, the device comprising:
- (a) an impeller having a top surface, a bottom surface, three or more sides, and at least one cavity in each of the sides open to the bottom surface;
(b) a shaft having a first end, a second end and a passage for transferring gas, the second end connected to the impeller;
(c) a drive source connected to the first end of the shaft, the drive source for rotating the shaft and the impeller; and
(d) one or more gas-release openings positioned in or beneath the bottom surface;
whereby a gas source is supplied to the passage of the shaft, and the drive source is operated to rotate the shaft and impeller and the gas passes through the passage and is released through the one or more gas-release openings and at least some of the gas enters the cavities, where it is mixed with molten metal and the molten metal/gas mixture is displaced by the impeller.
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Accused Products
Abstract
A device for dispersing gas into molten metal includes an impeller and a shaft having a first end and a second end. The second end of the shaft is connected to the impeller and the first end is connected to the drive source that rotates the shaft and impeller. The impeller includes a bottom surface, one or more cavities open to the bottom surface, one or more gas-release openings and a connector. The shaft has a gas-transfer passage therein. A gas source is connected to the first end of the shaft. Gas is transferred through the gas-transfer passage and exits through the gas-release opening(s). At least some of the gas enters the cavities where it is mixed with the molten metal being displaced by the impeller. The configuration of the impeller causes the gas and metal to mix efficiently throughout the molten metal bath. Also disclosed are dual-flow and tri-flow impellers that can be used to practice the invention.
298 Citations
39 Claims
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1. A device for releasing gas into molten metal, the device comprising:
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(a) an impeller having a top surface, a bottom surface, three or more sides, and at least one cavity in each of the sides open to the bottom surface;
(b) a shaft having a first end, a second end and a passage for transferring gas, the second end connected to the impeller;
(c) a drive source connected to the first end of the shaft, the drive source for rotating the shaft and the impeller; and
(d) one or more gas-release openings positioned in or beneath the bottom surface;
whereby a gas source is supplied to the passage of the shaft, and the drive source is operated to rotate the shaft and impeller and the gas passes through the passage and is released through the one or more gas-release openings and at least some of the gas enters the cavities, where it is mixed with molten metal and the molten metal/gas mixture is displaced by the impeller. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 35, 36)
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16. A device for releasing gas into molten metal contained within a vessel having a vessel wall and a vessel bottom, said device comprising:
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(a) a drive source;
(b) a shaft having a first end, a second end and a passage for transferring gas, the first end connected to the drive source; and
(c) a dual-flow impeller including a bottom surface and a plurality of vanes, wherein each of the vanes includes;
(i) a first surface for moving molten metal downward towards the vessel bottom, the first surface being formed at an angle other than vertical;
(ii) a second surface for moving molten metal outwards away from the impeller, the second surface being positioned closer to the vessel bottom than the first surface; and
(d) one or more gas-release openings. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 37, 38)
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24. An impeller for use in a device that mixes gas with molten metal, the impeller being square in plan view, having four sides, a top surface, a bottom surface, and comprising:
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(a) one or more gas-release openings for releasing gas into a molten metal bath; and
(b) cavity means for mixing gas with the molten metal. - View Dependent Claims (25, 26, 30, 31, 32, 33, 34)
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27. A device for releasing gas into molten metal contained in a vessel, the vessel having a bottom, the device comprising:
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(a) a shaft having a first end, a second end and a passage therein for the transfer of gas;
(b) a tri-flow impeller comprising;
(i) a connective portion connected to the second end of the shaft;
(ii) a plurality of vanes wherein;
(1) at least one vane includes a first surface for moving molten metal downward towards the vessel bottom, the first surface being formed at an angle other than vertical;
(2) at least one vane includes a second surface for moving molten metal outward away from the impeller; and
(3) at least one vane includes a third surface for moving molten metal upward away from the vessel bottom, the third surface being formed at an angle other than vertical;
(c) one or more gas-release openings in communication with the passage; and
(d) a drive source connected to the first end of the shaft, the drive source for rotating the shaft and the impeller. - View Dependent Claims (28, 29, 39)
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Specification