US5438588A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Direct current-electric arc furnace system
Assignee: Concast Standard AG
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Filing: 1994-03-17
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Granted: 1995-08-01
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Expires: 2014-03-17
Abstract
Abstract The direct current-electric arc furnace system includes a furnace vessel 8, one or more electric arc electrode 7 connected as a cathode, a bottom contact 12 connected as an anode, a furnace transformer 2 and a rectifier assembly 5 for feeding the furnace, an electrode control system E, and a current regulator I. A choke 6 is switched into the direct current main current circuit. A voltage control circuit F underlies the current control circuit I, whereby the output voltage of the current regulator 14 delivers the desired value for the voltage regulator 24. A filter 25 tuned to the flicker frequency follows the voltage regulator 24 with a frequency response, which is tuned to the frequency sensitivity of the human eye. Optionally, an additional control voltage signal U flick that is delivered by flicker meter can be provided to the voltage control circuit F. With a furnace control constructed in such a manner it is possible to obtain an optimal integration of the effective power that is made available by the furnace transformer 2 and rectifier 5 and simultaneously to dampen modulation swings and thus reactive power surges that lead to flicker.
Inventors
- 👤 Ernst Wanner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:14
CPC Classifications
H; H05; H05B; H05B7/00; H05B7/02; H05B7/144; H05B7/148; C; C21; C21C; C21C5/00; C21C5/52; C21C5/5229; H05B7/156; Y; Y02; Y02P; Y02P10/00; Y02P10/20; Y02P10/25
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
257 words
A direct current-electric arc furnace system comprising: a) a furnace having (i) a furnace vessel, (ii) at least one electric arc electrode connected to said furnace vessel and serving as a cathode, and (iii) a bottom contact connected to said furnace vessel and serving as an anode; b) a furnace transformer for supplying a voltage between said anode and said cathode of said furnace to generate an electric arc current therebetween; c) an electrode control circuit for controlling a position of said electric arc electrode; d) a current control circuit, for maintaining said electric arc current constant, said current control circuit including a rectifier connected between said furnace transformer and said at least one electric arc electrode, for regulating a voltage supplied from said furnace transformer to said at least one electric arc electrode; and e) a voltage regulating circuit including (i) a multiplier for receiving a voltage output from said current control circuit and multiplying said voltage by a first value to generate an output, (ii) a summing circuit for summing said output of said multiplier and a voltage output from said rectifier to generate a voltage output, (iii) a voltage regulator for regulating said voltage output from said summing circuit, and (iv) a filter exhibiting a frequency characteristic which is tuned to a filter frequency perceivable by the human eye, for eliminating components of said output of said voltage regulator having said filter frequency and outputting a filtered signal to said rectifier for controlling said voltage applied to said at least one electric arc electrode.
Claim 2
Dependent Claim
257 words
A direct current-electric arc furnace system comprising: a) a furnace having (i) a furnace vessel, (ii) at least one electric arc electrode connected to said furnace vessel and serving as a cathode, and (iii) a bottom contact connected to said furnace vessel and serving as an anode; b) a furnace transformer for supplying a voltage between said anode and said cathode of said furnace to generate an electric arc current therebetween; c) an electrode control circuit for controlling a position of said electric arc electrode; d) a current control circuit, for maintaining said electric arc current constant, said current control circuit including a rectifier connected between said furnace transformer and said at least one electric arc electrode, for regulating a voltage supplied from said furnace transformer to said at least one electric arc electrode; and e) a voltage regulating circuit including (i) a multiplier for receiving a voltage output from said current control circuit and multiplying said voltage by a first value to generate an output, (ii) a summing circuit for summing said output of said multiplier and a voltage output from said rectifier to generate a voltage output, (iii) a voltage regulator for regulating said voltage output from said summing circuit, and (iv) a filter exhibiting a frequency characteristic which is tuned to a filter frequency perceivable by the human eye, for eliminating components of said output of said voltage regulator having said filter frequency and outputting a filtered signal to said rectifier for controlling said voltage applied to said at least one electric arc electrode.
Claim 3
Dependent Claim
32 words
A direct current-electric arc furnace system according to claim 1, wherein said first value of said multiplier is a correction value generated in accordance with said voltage supplied by said furnace transformer.
Claim 4
Dependent Claim
68 words
A direct current-electric arc furnace system according to claim 2, further comprising: a voltage transformer for transforming said voltage supplied by said furnace transformer; a flicker meter for receiving an output of said voltage transformer and detecting reactive power surges and flicker in said output; and a signalling device for receiving an output of said flicker meter and generating said correction value to be supplied to said multiplier.
Claim 5
Dependent Claim
68 words
A direct current-electric arc furnace system according to claim 2, further comprising: a voltage transformer for transforming said voltage supplied by said furnace transformer; a reactive power meter for receiving an output of said voltage transformer and detecting reactive power surges in said output; and a signalling device for receiving an output of said reactive power meter and generating said correction value to be supplied to said multiplier.
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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) | 1998-07-31 | 1999-01-30 | 1999-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-07-31 | 2003-01-30 | 2003-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-07-31 | 2007-01-30 | 2007-08-01 | $7700.00 | Window Closed / Lapsed |