US3627666A - Apparatus for automatically regulating the anode gap in electrolysis cells - Google Patents

Apparatus for automatically regulating the anode gap in electrolysis cells Download PDF

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Publication number
US3627666A
US3627666A US771834A US3627666DA US3627666A US 3627666 A US3627666 A US 3627666A US 771834 A US771834 A US 771834A US 3627666D A US3627666D A US 3627666DA US 3627666 A US3627666 A US 3627666A
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Prior art keywords
relay
cell
voltage
cells
potentiometer
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Expired - Lifetime
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US771834A
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English (en)
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Rene L Bonfils
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Pechiney SA
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Pechiney SA
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
    • C25C3/20—Automatic control or regulation of cells

Definitions

  • This invention relates to an apparatus for automatically regulating the anode gap in electrolysis cells.
  • the apparatus of this invention has particular advantage, in igneous electrolysis cells of the kind used in the production of aluminum, irrespective of whether the cells in question employ a continuous anode or a plurality of prebaked anodes, but the concepts are applicable also to other cells.
  • the anode gap of electrolysis cells can be automatically regulated by measuring a pseudoresistance taken as being equal to in which R is the pseudoresistance, U is the voltage at the terminals of the cell in question, e is the counterelectromotive force of electrolysis, I is the intensity of the current passing through the cell.
  • This pseudoresistance is then compared with a reference value R0, after which a motor controlling the position of one of the electrodes, i.e., the anode or cathode, is given a pulse whose sign is governed by that of R-Ro so that the anode gap increases if R-Ro is negative and decreases if positive.
  • the present invention relates to an apparatus for automatically regulating the anode gap in electrolysis cells which is simple, inexpensive, and unaffected by the atmosphere prevailing inside the electrolysis plant.
  • kRI which, through its regulation, can be made equal to kRI, where R is the predetermined value of the internal resistance of the cell
  • a third circuit comprising at least one threshold relay which is connected in series with the first two circuits arranged in opposed relation, and which emits an electric impulse every time that k( U-RI) differs from ice by more than a predetermined quantity, the sign of this pulse being governed by that ofkek( URI).
  • FIG. 1 is a block diagram of the regulating apparatus
  • FIG. 2 is a graph illustrating the operation of the apparatus illustrated in FIG. 1;
  • FIG. 3 is a modification ofa detail ofan element in FIG. 1.
  • a regulator which can only comprise static elements that are both inexpensive and unafiected by the surrounding atmosphere, by electrically establishing the value U-Rl where R is a predetermined value adopted for the internal resistance of the cell, and by giving a regulating order or command in the form of an identical electrical impulse every time that U-Rl is outside the range between two limiting values e-a and e+a where a is half the permissible deviation which is allowed on the value e.
  • FIG. 1 illustration is made in FIG. 1 of an electrolysis cell 5 with a cathode 51 connected to a pole 54, and an anode 52 connected to a pole 53.
  • the anode may have a vertical translatory movement imparted to it by the action of an electric motor 55, such as of the direct current or single-phase type, fed through its terminals 56 and 57.
  • An electrolysis current flows into the cell through the pole 53, flows through the anode 52, through the space between the electrodes and then through the cathode 51, leaving via the pole 54.
  • the voltage between the poles 53 is designated by the letter U, and the current which flows through the cell by I.
  • electrolysis takes place at an extremely high intensity of from about 65 to kiloamperes. Accordingly, a certain number of cells are branched in series in order to increase the overall voltage. Connected in series with the cells thus branched is a shunt 6 of which one terminal 61 is connected to the pole 54 of the cell and the other terminal 62 is connected to the negative pole of the device by which the cells of the series are fed.
  • the regulating apparatus comprises a first circuit consisting of an input voltage converter 1, a second circuit comprising an intensity converter 2 and a potentiometer 3 and finally a third circuit comprising at least one threshold relay 4.
  • the input converters enable the regulating apparatus to be isolated from the potential of the cell being regulated.
  • Each converter may comprise, for example, one modulator, one transformer and one demodulator.
  • the input voltage converter 1 supplies a voltage kU proportional to U. It comprises two input terminals II and 12 connected to the poles 54 and 53, respectively, of the cell, and two output terminals 13 and 14 between which the voltage kU appears.
  • the potentiometer 3 has two input terminals 31 and 32 connected to the output terminals 23 and 24, respectively, of the input intensity converter 2. It is regulated by means of a slide 33. Thus, between its output terminals 33 and 32, it supplies a voltage proportional to its input current k'l, that is to say a voltage equal to k'k"I.
  • the potentiometer is regulated in such a way that k'k"! is equal to kRl.
  • the potentiometer may be directly graduated in units of R, the predetermined value of the internal resistance of the cell 5.
  • the threshold relay 4 has two input terminals 41 and 42 connected to the terminals 13 and 33, respectively, and two output terminals 43 and 44 connected to the poles 57 and 56, respectively, of the motor 55 controlling the translatory movement of the anode 52.
  • the relay has a threshold ka, in other words it only emits a current impulse that is always identical between its output terminals 43 and 44 if k(URI) is outside the range between k(ea) andk(e+), that is to say if U-RI is outside the range between (e-wz) and (e-l-a). if this is in fact the case, the relay '3 transmits an impulse which, though of the same intensity, has a polarity governed by the sign of the difference U-RI-e.
  • the polarity is such that the motor 55, once it has been started, reduces the anode gap, whereas if U-R1 is smaller than e-a, the polarity is inverse, and the motor 55 increases the anode gap.
  • the intensity I has been plotted as the abscissa in FIG. 2 and the voltage U as the ordinate.
  • the ordinate dots (e-a), e, and (e-l-a) are plotted on the axis of the U s, the first and the last of these values representing the limiting values ensured by regulation at the counter electromotive force of electrolysis.
  • a second relay 7 which is branched in exactly the same way, i.e., whose input terminals 71 and 72 are connected to the corresponding terminals 41 and 42, respectively, of the relay 4 and whose output terminals 73 and 74 are connected to the corresponding terminals $3 and 44, respectively.
  • This relay only functions when U-RI is smaller than e-a', where a is a predetermined quantity, very much greater than a (for example five times greater in the case of an actual reduction to practice).
  • This relay 7 transmits an electric impulse to the motor 55 which is either more powerful or of longer duration than that delivered by the relay 4.
  • a third relay 3 which, in the event of a lack of stability in the operation of the cell, causes the anode to ascend quickly.
  • This relay is of the same type as the relay 7 except that one of its input terminals, for example the terminal 81, is connected to the corresponding terminal 41 of the relay 3 through a capacitor which only allows unstable oscillations through.
  • the other input terminal 82 is connected to the terminal 62 while the output terminals 83 and 84 are connected to the corresponding terminals 43 and 44, respectively.
  • a fourth relay 9 may be provided for the purpose of interrupting the regulation of a cell too far outside the normal regulating tolerances.
  • the input terminals 91 and 92 of this relay are connected respectively to the terminals 41 and 42 while the output terminals 93 and 94 are incorporated in one of the connecting lines, for example the line 43-57 connecting the regulator to the motor 55.
  • This relay 9 is identical with the relay 4 except that its threshold is regulated to ka" where a" is greater than a.
  • the relay '7 is activated and transmits to the motor 55 a current impulse of either greater power or longer duration which starts the motor moving at a faster speed: the anode thus rises quickly until k( U-Rl) is again similar to ke.
  • k(U-Rl) undergoes rapid fluctuations which, filtered by the capacitor 85, affect the relay 8 which then functions like the relay 7 and ensures rapid ascent of the anode.
  • connections 11-54, 12-53 and 94-57 merely have to be switched providing that the same reference value R can be used for all the cells connected to one and the same regulator. if it is desired to be able independently to fix this value for each of the cells, the connecting lines 33-82 and 23-31 will also have to be switched and separate potentiome ter provided for each cell.
  • this potentiometer 10 it is possible by means of this potentiometer 10 to deliver to the regulator a fraction U, rather than all, of the cell voltage. in this case, the regulator keeps the cell at a higher voltage so that U is equal to U,,, the predetermined value for normal intensity.
  • An apparatus as claimed in claim 1 in which the regulator serves a plurality of cells in series, and which includes a switch between the poles of the cell and the voltage converter, and between the threshold relay and the motor.
  • An apparatus as claimed in claim 3 which includes a second potentiometer between the poles of the cell and the voltage converted, said second potentiometer enabling the reference value selected for the internal resistance to the individually regulated for the cells, the regulation of the first potentiometer remaining the same for all of the cells.
  • the third circuit comprises a second threshold relay branching parallel from the first which is only actuated when U-Rl is smaller than e-a', and in which a is a predetermined quantity considerably larger than a, said second relay being connected to the control motor for delivery of an electrical impulse more powerful than that delivered by the first relay to enable the electrode being controlled rapidly to rise in the event of resistance.
  • An apparatus as claimed in claim 1 which includes a third relay having its input connected in parallel with the input of the first relay through a capacitor which only allows unstable oscillations to pass therethrough, the output of said third relay being connected in parallel with the output of the first relay, said third relay causing the controlled electrode quickly to rise in the event of any instability in the cell.
  • An apparatus as claimed in claim 1 which includes a fourth relay having its input connected in parallel with the input of the first relay and its output connected in series with the circuit feeding the control motor, said fourth relay corresponding to the first relay except that its threshold is regulated to a value ka", in which a", is greater than a, said fourth relay enabling regulation to be interrupted whenever a cell is beyond the normal regulating force.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Engineering & Computer Science (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Hybrid Cells (AREA)
  • Motor And Converter Starters (AREA)
  • Feedback Control In General (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
  • Control Of Position Or Direction (AREA)
US771834A 1967-11-06 1968-10-30 Apparatus for automatically regulating the anode gap in electrolysis cells Expired - Lifetime US3627666A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR127012A FR1605433A (ja) 1967-11-06 1967-11-06

Publications (1)

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US3627666A true US3627666A (en) 1971-12-14

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US771834A Expired - Lifetime US3627666A (en) 1967-11-06 1968-10-30 Apparatus for automatically regulating the anode gap in electrolysis cells

Country Status (13)

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US (1) US3627666A (ja)
JP (2) JPS4818710B1 (ja)
AT (1) AT293738B (ja)
BE (1) BE723451A (ja)
CH (1) CH506326A (ja)
DE (1) DE1807336B2 (ja)
ES (1) ES359882A1 (ja)
FR (1) FR1605433A (ja)
GB (1) GB1251519A (ja)
NL (1) NL164616C (ja)
NO (1) NO124784B (ja)
RO (1) RO54518A (ja)
SE (1) SE356535B (ja)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3888747A (en) * 1972-10-18 1975-06-10 Nat Southwire Aluminum Method of and apparatus for producing metal
US4008142A (en) * 1973-07-25 1977-02-15 Siemens Aktiengesellschaft Apparatus for operating the furnaces of an electrolysis plant
US4069118A (en) * 1975-11-10 1978-01-17 Stauffer Chemical Company Electrolysis control apparatus and method
US5785826A (en) * 1996-12-26 1998-07-28 Digital Matrix Apparatus for electroforming
US5843296A (en) * 1996-12-26 1998-12-01 Digital Matrix Method for electroforming an optical disk stamper
US20040055873A1 (en) * 2002-09-24 2004-03-25 Digital Matrix Corporation Apparatus and method for improved electroforming

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3396095A (en) * 1964-01-24 1968-08-06 Solvay Method and apparatus for the continuous regulation of the distance between the electrodes of electrolytic cells with liquid mecury cathodes
US3434945A (en) * 1963-08-30 1969-03-25 Alusuisse Terminal voltage regulation in electrolytic aluminum production
US3455795A (en) * 1964-01-14 1969-07-15 Pechiney Prod Chimiques Sa Apparatus and method for the operation of cells for the igneous electrolysis of alumina
US3480528A (en) * 1964-10-19 1969-11-25 Solvay Process for the adjustment of the distance between the electrodes of operating electrolysis cells
US3531392A (en) * 1965-11-11 1970-09-29 Knapsack Ag Arrangement for measuring the current intensity at the single electrodes of electrolytic cells
US3558454A (en) * 1967-07-04 1971-01-26 Bayer Ag Method of regulating voltage and eliminating short circuits in cells for the electrolysis of alkali metal chlorides
US3573179A (en) * 1965-12-14 1971-03-30 Ibm Method and apparatus for the control of electrolytic refining cells

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3434945A (en) * 1963-08-30 1969-03-25 Alusuisse Terminal voltage regulation in electrolytic aluminum production
US3455795A (en) * 1964-01-14 1969-07-15 Pechiney Prod Chimiques Sa Apparatus and method for the operation of cells for the igneous electrolysis of alumina
US3396095A (en) * 1964-01-24 1968-08-06 Solvay Method and apparatus for the continuous regulation of the distance between the electrodes of electrolytic cells with liquid mecury cathodes
US3480528A (en) * 1964-10-19 1969-11-25 Solvay Process for the adjustment of the distance between the electrodes of operating electrolysis cells
US3531392A (en) * 1965-11-11 1970-09-29 Knapsack Ag Arrangement for measuring the current intensity at the single electrodes of electrolytic cells
US3573179A (en) * 1965-12-14 1971-03-30 Ibm Method and apparatus for the control of electrolytic refining cells
US3558454A (en) * 1967-07-04 1971-01-26 Bayer Ag Method of regulating voltage and eliminating short circuits in cells for the electrolysis of alkali metal chlorides

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3888747A (en) * 1972-10-18 1975-06-10 Nat Southwire Aluminum Method of and apparatus for producing metal
US4008142A (en) * 1973-07-25 1977-02-15 Siemens Aktiengesellschaft Apparatus for operating the furnaces of an electrolysis plant
US4069118A (en) * 1975-11-10 1978-01-17 Stauffer Chemical Company Electrolysis control apparatus and method
US5785826A (en) * 1996-12-26 1998-07-28 Digital Matrix Apparatus for electroforming
US5843296A (en) * 1996-12-26 1998-12-01 Digital Matrix Method for electroforming an optical disk stamper
US20040055873A1 (en) * 2002-09-24 2004-03-25 Digital Matrix Corporation Apparatus and method for improved electroforming

Also Published As

Publication number Publication date
BE723451A (ja) 1969-05-06
NL164616B (nl) 1980-08-15
ES359882A1 (es) 1970-06-16
GB1251519A (ja) 1971-10-27
JPS5637318B2 (ja) 1981-08-29
NO124784B (ja) 1972-06-05
JPS4818710B1 (ja) 1973-06-07
NL6815719A (ja) 1969-05-08
DE1807336A1 (de) 1971-02-11
JPS527314A (en) 1977-01-20
CH506326A (fr) 1971-04-30
DE1807336B2 (de) 1971-11-04
FR1605433A (ja) 1975-10-17
SE356535B (ja) 1973-05-28
NL164616C (nl) 1981-01-15
AT293738B (de) 1971-10-25
RO54518A (ja) 1973-02-17

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