US4462457A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transformer-driven shield for electromagnetic casting
Assignee: Olin Corp
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Filing: 1982-09-22
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Granted: 1984-07-31
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Expires: 2002-09-22
Abstract
Abstract An electromagnetic casting process and apparatus utilizing an active transformer-driven copper shield. The shield is actively driven with a voltage out of phase with the voltage in the containment inductor with the result that a bucking current is produced in the shield which is out of phase with the current induced in the shield by the inductor. An active transformer-driven duplex variable impedance shield is also disclosed.
Inventors
- 👤 Peter J. Kindlmann
- 👤 John C. Yarwood
- 👤 Gary L. Ungarean
- 👤 Derek E. Tyler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 01:09
CPC Classifications
B; B22; B22D; B22D11/00; B22D11/01; B22D11/015
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
107 words
An apparatus for shape control in electromagnetic casting of molten materials, comprising: means for providing a magnetic field; an active non-magnetic shield comprising a primary loop magnetic field shielding means for attenuating said magnetic field by intercepting a portion of said magnetic field so that a current is induced in said shielding means; and means for delivering a bucking current to said primary loop shielding means, said bucking current being selected such that it is out of phase with said current induced in said shielding means by said magnetic field whereby in operation the resulting net current in said shielding means is less than the induced curent.
Claim 2
Independent Claim
107 words
An apparatus for shape control in electromagnetic casting of molten materials, comprising: means for providing a magnetic field; an active non-magnetic shield comprising a primary loop magnetic field shielding means for attenuating said magnetic field by intercepting a portion of said magnetic field so that a current is induced in said shielding means; and means for delivering a bucking current to said primary loop shielding means, said bucking current being selected such that it is out of phase with said current induced in said shielding means by said magnetic field whereby in operation the resulting net current in said shielding means is less than the induced curent.
Claim 3
Dependent Claim
19 words
An active non-magnetic shield as in claim 1 further including means for adjusting the phase of said bucking current.
Claim 4
Dependent Claim
23 words
An active non-magnetic shield as in claim 2 wherein said adjusting means comprises a capacitor connected in series with said primary shielding means.
Claim 5
Dependent Claim
31 words
An active non-magnetic shield as in claim 3 wherein said means for delivering a bucking current comprises a transformer, the secondary of which is connected to said primary loop shielding means.
Claim 6
Dependent Claim
22 words
An active non-magnetic shield as in claim 4 constructed of a material selected from the group comprising copper, aluminum, and alloys thereof.
Claim 7
Dependent Claim
20 words
An active non-magnetic shield as in claim 4 further including means for varying the overall impedance of said shielding means.
Claim 8
Dependent Claim
26 words
An active non-magnetic shield as in claim 6 further including a secondary loop attached to said primary loop shielding means to also carry said bucking current.
Claim 9
Dependent Claim
49 words
An active non-magnetic shield as in claim 7 wherein said secondary loop includes two legs and a movable shunt means in bridging engagement therewith adapted for movement along said legs, whereby the impedance of said secondary loop and, therefore, the overall impedance of said shielding means can be varied.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-07-31 | 1988-01-30 | 1988-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-31 | 1992-01-30 | 1992-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-31 | 1996-01-30 | 1996-07-31 | $7700.00 | Window Closed / Lapsed |