US4024034A
Expired / Lapsed
US
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Method for operating the furnaces of an electrolysis plant
Assignee: Siemens AG
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Filing: 1975-08-11
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Granted: 1977-05-17
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Expires: 1995-08-11
Abstract
Abstract A method and apparatus for operating an electrolysis plant including a plurality of furnaces in which the anode spacing of each furnace is controlled by means of a computer as a function of furnace resistance. A desired furnace resistance is varied as a function of the furnace current yield, the optimum of which is given by a selected number of furnace voltage variations which exceed a specified voltage level, and, in addition, as a function of furnace energy consumption as indicated by the furnace resistance gradient, the rate of change of that gradient, and the difference between the expected furnace metal production with respect to long-term current yield and the measured furnace metal production.
Inventors
- 👤 Christfried Doring
- 👤 Johann Thomas
- 👤 Manfred Volcker
- 👤 Volker Sparwald
- 👤 Walter Habersack
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:03
CPC Classifications
C; C25; C25C; C25C3/00; C25C3/06; C25C3/20; G; G05; G05B; G05B13/00; G05B13/02
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
121 words
In a method of operating an electrolysis plant which includes a plurality of furnaces, and in which the anode spacing of each furnace is controlled by a computer as a function of furnace resistance, said furnace resistance being calculated from furnace current and voltage, the improvement comprising selecting a desired furnace resistance and adjusting said desired resistance in response to the detection of a selected number of furnace voltage variations which exceed a specified voltage level, and, additionally, in response to the calculated furnace resistance, variations of the furnace resistance gradient, variations, of the rate of change of said gradient, and the difference between the expected furnace metal production with respect to long-term current yield and the measured furnace metal production.
Claim 2
Dependent Claim
121 words
In a method of operating an electrolysis plant which includes a plurality of furnaces, and in which the anode spacing of each furnace is controlled by a computer as a function of furnace resistance, said furnace resistance being calculated from furnace current and voltage, the improvement comprising selecting a desired furnace resistance and adjusting said desired resistance in response to the detection of a selected number of furnace voltage variations which exceed a specified voltage level, and, additionally, in response to the calculated furnace resistance, variations of the furnace resistance gradient, variations, of the rate of change of said gradient, and the difference between the expected furnace metal production with respect to long-term current yield and the measured furnace metal production.
Claim 3
Dependent Claim
24 words
The method recited in claim 1, wherein said desired furnace resistance is adjusted only when said furnace current remains within predetermined limits selected therefor.
Claim 4
Dependent Claim
61 words
The method of claim 2, wherein said desired furnace resistance value is increased by a predetermined increment in response to said selected number of furnace voltage variations exceeding said specified voltage level, and is decreased by the same increment in the absence of said selected number of said furnace voltage variations exceeding said specified level over a predetermined period of time.
Claim 5
Dependent Claim
41 words
The method recited in claim 3, wherein each desired furnace resistance value adjustment is effected only after a predetermined time interval subsequent to a previous adjustment thereof, said interval corresponding to the time intervals between adjustments in the furnace anode spacing.
Claim 6
Dependent Claim
30 words
The method recited in claim 4, wherein the occurrence of said number of furnace voltage variations exceeding said specified level subsequent to adjustment of said furnace resistance is visually indicated.
Claim 7
Dependent Claim
33 words
The method recited in claim 5, wherein said furnace resistance is readjusted to said desired resistance value subsequent to adjustment thereof by said computer after correction of the condition causing said adjustment thereof.
Claim 8
Dependent Claim
23 words
The method recited in claim 6, wherein said furnace resistance gradient comprises the mean value of a plurality of furnace resistance mean values.
Claim 9
Dependent Claim
26 words
The method recited in claim 7, wherein said rate of change of said resistance gradient comprises the difference between a pair of consecutively determined resistance gradients.
Claim 10
Dependent Claim
56 words
The method recited in claim 8, wherein said desired furnace resistance is increased by said computer in response to an increase in the measured resistance gradient and the rate of change of said resistance gradient, and is decreased by said computer in response to a decrease of said resistance gradient below a selected lower limit therefor.
Claim 11
Dependent Claim
68 words
The method recited in claim 9, wherein adjustment of said anode spacing of said furnaces is effected only whenever said resistance gradient does not exceed an upper selected limit therefor and said rate of change of said resistance gradient does not exceed an upper limit therefor simultaneously with said resistance gradient, and wherein an impending anode effect is visually indicated by an output signal generated by said computer.
Claim 12
Dependent Claim
36 words
The method recited in claim 10, wherein said current yield is determined from continuously sliding mean values therefor within a selected period of time required for the equalization of the statistical variations of furnace metal production.
Claim 13
Dependent Claim
20 words
The method recited in claim 11, wherein said expected metal production is calculated from long term current yield values therefor.
Claim 14
Dependent Claim
36 words
The method recited in claim 12, wherein said difference between said expected and actual metal production is continuously calculated, and wherein an output signal is generated by said computer whenever a limit selected therefor is exceeded.
Claim 15
Dependent Claim
53 words
The method recited in claim 13, wherein said desired furnace resistance is increased as a function of a positive difference, which exceeds a predetermined limit, between said actual and expected metal production, and is decreased in response to a negative difference which exceeds a predetermined limit, between said actual and expected metal production.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-16 | 1980-11-15 | 1981-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-16 | 1984-11-15 | 1985-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-16 | 1988-11-15 | 1989-05-17 | $7700.00 | Window Closed / Lapsed |