US4034146A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for equalizing the wall lining wear in three phase alternating current electric arc furnaces
Assignee: ABB Norden Holding AB
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Filing: 1976-01-27
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Granted: 1977-07-05
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Expires: 1996-01-27
Abstract
Abstract Method and apparatus for increasing the life of the lining of a three phase AC electric arc furnace. An electro-magnetic coil, mounted under the furnace and powered by DC or low frequency AC sets up a magnetic field inside the furnace, intersecting the arcs. During consecutive half cycles of the alternating arc current, the arcs are then steered away, alternating between new positions on both sides of the usual hot spot areas on the furnace wall.
Inventors
- 👤 Sven-Einar Stenkvist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:37
CPC Classifications
F; F27; F27D; F27D11/00; C; C21; C21C; C21C5/00; C21C5/52; C21C5/5229; H; H05; H05B; H05B7/00; H05B7/02; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
113 words
A method of equalizing the wear of the wall lining in a three-phase AC electric arc furnace by using a magnetic field arranged substantially symmetrically to the electrodes and intersecting the arcs in the furnace space above the charge, the method comprising passing said magnetic field to the furnace space through the furnace bottom lining and the furnace charge, and maintaining the polarity of the magnetic field unchanged during a period of time substantially exceeding the time period of one complete cycle of the electrode supply current thereby deflecting the arcs alternatingly towards both sides of the arc directions resulting solely from the magnetic fields created by the currents passing through the electrodes.
Claim 2
Independent Claim
113 words
A method of equalizing the wear of the wall lining in a three-phase AC electric arc furnace by using a magnetic field arranged substantially symmetrically to the electrodes and intersecting the arcs in the furnace space above the charge, the method comprising passing said magnetic field to the furnace space through the furnace bottom lining and the furnace charge, and maintaining the polarity of the magnetic field unchanged during a period of time substantially exceeding the time period of one complete cycle of the electrode supply current thereby deflecting the arcs alternatingly towards both sides of the arc directions resulting solely from the magnetic fields created by the currents passing through the electrodes.
Claim 3
Dependent Claim
18 words
A method according to claim 1, comprising keeping the polarity of the magnetic field intersecting the arcs constant.
Claim 4
Dependent Claim
31 words
A method according to claim 1, comprising reversing the polarity of the magnetic field intersecting the arcs periodically with a frequency less than half the frequency of the electrode supply current.
Claim 5
Dependent Claim
19 words
A method according to any of claim 1, comprising varying the strength of the magnetic field intersecting the arcs.
Claim 6
Independent Claim
90 words
An apparatus for equalizing the wear of the wall lining in a three-phase AC electric arc furnace, including means for creating a magnetic field arranged substantially symmetrically to the electrodes and intersecting the arcs in the furnace space above the charge, the apparatus comprising at least one electromagnetic coil mounted under the furnace bottom lining and means for supplying an electric current to said coil of a polarity which is unchanged during a period of time substantially exceeding the time period of one complete cycle of the electrode supply current.
Claim 7
Independent Claim
90 words
An apparatus for equalizing the wear of the wall lining in a three-phase AC electric arc furnace, including means for creating a magnetic field arranged substantially symmetrically to the electrodes and intersecting the arcs in the furnace space above the charge, the apparatus comprising at least one electromagnetic coil mounted under the furnace bottom lining and means for supplying an electric current to said coil of a polarity which is unchanged during a period of time substantially exceeding the time period of one complete cycle of the electrode supply current.
Claim 8
Dependent Claim
15 words
An apparatus according to claim 5, comprising means for supplying DC current to said coil.
Claim 9
Dependent Claim
28 words
An apparatus according to claim 5, comprising means for supplying AC current to said coil of a frequency less than half the frequency of the electrode supply current.
Claim 10
Dependent Claim
19 words
An apparatus according to claim 5, comprising means for varying the strength of the current supplied to said coil.
Claim 11
Dependent Claim
23 words
An apparatus according to any of claim 5, wherein said coil is arranged outside the furnace bottom beneath a non-magnetic shell portion thereof.
Claim 12
Dependent Claim
35 words
An apparatus according to any of claim 5, wherein said coil is provided with a core or yoke means of magnetic material in order to increase the strength of the magnetic field inside the furnace.
Claim 13
Dependent Claim
21 words
An apparatus according to claim 10, wherein a coil suspension arrangement forms a core or yoke means in the magnetic circuit.
References Cited (Backward Citations)
GB252037A
Cited
US3409726A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-04 | 1981-01-03 | 1981-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-04 | 1985-01-03 | 1985-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-04 | 1989-01-03 | 1989-07-05 | $7700.00 | Window Closed / Lapsed |