US3598714A - Apparatus for protecting the anodes of an electrolytic cell against short circuiting - Google Patents

Apparatus for protecting the anodes of an electrolytic cell against short circuiting Download PDF

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Publication number
US3598714A
US3598714A US770045A US3598714DA US3598714A US 3598714 A US3598714 A US 3598714A US 770045 A US770045 A US 770045A US 3598714D A US3598714D A US 3598714DA US 3598714 A US3598714 A US 3598714A
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US
United States
Prior art keywords
anodes
anode
short
cell
cathode
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Expired - Lifetime
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US770045A
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English (en)
Inventor
Robert Schoberle
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Solvay SA
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Solvay SA
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Publication date
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/60—Constructional parts of cells
    • C25B9/65—Means for supplying current; Electrode connections; Electric inter-cell connections
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B15/00—Operating or servicing cells
    • C25B15/06—Detection or inhibition of short circuits in the cell

Definitions

  • the present invention relates to a method and an apparatus which prevents short-circuits between electrodes in a cell with a flowing mercury cathode for the electrolysis of aqueous solutions of alkali metal halides, without interrupting the electrolysis at any of the anodes of the cell.
  • the anodes are disposed as close as possible to the mercury cathode.
  • the distance between electrodes varies in general from 0.5 to 5.0 mm.; sometimes it is negative, that is the anodes are lowered several tenths of a millimetre beneath the normal level of the mercury surface, which enables very low electrolytic voltages to be used provided that the current density is high enough.
  • Their coating which generally consists of at least one metal of the platinum group or its oxide optionally mixed or alloyed with other metals or compounds, always offers a certain porosity which allows the atomic hydrogen formed to react with the metal underneath (titanium, tantalum, zirconium, niobium or their alloys) to form a hydride whose poor resistance to corrosion renders the anode useless.
  • the anode concerned, the anode group, or even the whole cell is always taken off load, that is all electrolysis is interrupted until the defective element is put back in place and in circuit.
  • the present invention avoids all these disadvantages. It relates to the automatic protection of the anodes of a cell with a flowing mercury cathode in a group of similar cells connected in series, against the effects of a shortcircuit due to contact with the mercury cathode while keeping all the anodes of the cell under electrolytic tension, i.e. without disconnecting any of them.
  • This protection is achieved by rapidly removing from the cathode, the anode or the group of anodes which is threatened with short-circuit, so as to increase substantially the anode-cathode gap, under the impulse of a shortcireuit detector.
  • the present invention also relates to an apparatus for effecting the displacement of one or more anodes before the short-circuit occurs between electrodes which comprises a bus-bar supporting the anode or group anodes, a flexible connection for leading current to said bus-bar, at least one electrically conducting probe protruding from the base of the anode plate, integral therewith and electrically insulated therefrom, short-circuit detector means electrically connected external to the cell between said probes and the cell base plate and means responsive to said detector means for raising the bus-bar so as to withdraw the anodes away from the cathode.
  • FIG. 1 is a schematic vertical sectional view of a horizontal cell
  • FIG. 2 is a similar view of a modified form of cell
  • FIG. 3 is a schematic fragmentary view, on an enlarged scale of a portion of a cell.
  • the rods 5 can be at least partially of titanium or a similar metal.
  • the substantially horizontal copper bar 7 conducts the current to the anode rods 5 which it supports; it is fed by a flexible connection *8 (for example a copper leaf) which connects it to the base-plate of the preceding cell in the series.
  • the adjusting nuts 9 limit the upward movement of the bar 7, thus determining the raised position of the anode, while the anode-cathode-gap adjusting nuts 10 fix the normal operating position of the anode. It is desirable to be able to adjust the movement of the bar 7 be tween 5 and mm. and accordingly the height of raising the anode 6 which is integral with it.
  • a pneumatic cylinder 11 releases the ascending movement of the anode under the impulse of a signal arising from the short-circuit detecting apparatus 19 (FIG. 3).
  • the approach of a shortcircuit is detected for each anode by means of one or more probes 20 projecting slightly from the active surface of the anode and connected to the apparatus for detecting a short circuit.
  • the probe 20 is carried by the anode plate through which it passes, but is electrically-insulated from the latter.
  • the probe 20 consists of a titanium wire whose protruding end is platinised, and the probe/ anode electrical insulation is ensured by a Teflon sheath 22 around the probe except at the platinised end.
  • one or more of the anode probes 20 makes contact with the mercury 18 so that the short circuit detecting means 19 causes removal of the anode before the latter makes contact with the liquid cathode, thus completely avoiding short-circuit between the electrodes.
  • the detecting means 19 may be activated by utilising the electrolysis current, by a contact voltmeter connected between the probes and the base-plate of the cell (which carries the flowing mercury cathode), or by recourse to an external source of low-strength current of which one pole is connected to the conducting base-plate and the other to the probe or to the group of probes which are connected in parellel.
  • the anode movement or the alarm signal will be activated by a contact ammeter connected in the circuit, for example between the probe and the current source, or again by a contact voltmeter or a relay tapped across the circuit and shunted by the probe.
  • the use of the probes according to the invention not only avoids untimely short-circuits during electrolysis, but also fixes a reference point when adjusting the anodes.
  • the electrolysis can be effected at a lower voltage because the anodes-cathodes gap can be distinctly smaller than in cells not provided with the protection apparatus claimed.
  • an electrolytic cell having at least one anode disposed above a base plate over which a mercury electrode flows, a vertically movable bus-bar supporting the anode, and a flexible electrical connection for leading current to said bus-bar, the improvement which protects the anode against a short circuit arising from contact thereof with the cathode, said improvement comprising: at least one electrically conducting probe protruding downwardly from the anode so as to be engageable with the cathode before contact between the anode and cathode occurs, said probe being carried by the anode and electrically insulated therefrom; short circuit detector means electrically connected external to the cell between the probe and the cell base plate for detecting a short circuit between the probe and the cathode; and means responsive to the detector means for raising the bus-bar to thereby withdraw the anode away from the cathode.
  • each of said probes consists of at least one titanium wire covered with Teflon except at the protruding end, which is platinised.
  • the short-circuit detector means comprises a contact voltmeter, connected between the said probe and the conducting base-plate of the cell and means for maintaining the voltmeter under electrolysis voltage when there is no short-circuit between any one cell and the cell cathode.
  • the short-circuit detector means comprises a contact ammeter connected in series with an auxiliary source of current between the said probes and the conducting baseplate of the cell.
  • the short-circuit detector means comprises a contact volt- 6 meter or a relay shunted across an auxiliary source of cur- 3,464,903 9/1969 Shaw 204-225X rent connected in an external circuit between the said 3,480,528 11/ 1969 Clement 204225X probes and the said conducting base-plate.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Metals (AREA)
US770045A 1967-10-31 1968-10-23 Apparatus for protecting the anodes of an electrolytic cell against short circuiting Expired - Lifetime US3598714A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
BE705921 1967-10-31
BE50297 1967-10-31
BE51167 1967-11-22
BE706879 1967-11-22

Publications (1)

Publication Number Publication Date
US3598714A true US3598714A (en) 1971-08-10

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Family Applications (1)

Application Number Title Priority Date Filing Date
US770045A Expired - Lifetime US3598714A (en) 1967-10-31 1968-10-23 Apparatus for protecting the anodes of an electrolytic cell against short circuiting

Country Status (6)

Country Link
US (1) US3598714A (hu)
BE (2) BE705921A (hu)
DE (1) DE1805460A1 (hu)
FR (1) FR1604383A (hu)
GB (1) GB1224760A (hu)
NL (1) NL6814586A (hu)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3902983A (en) * 1974-01-07 1975-09-02 Olin Corp Method and apparatus for preventing voltage extremes in an electrolytic cell having automatic adjusting of the anode-cathode spacing

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3902983A (en) * 1974-01-07 1975-09-02 Olin Corp Method and apparatus for preventing voltage extremes in an electrolytic cell having automatic adjusting of the anode-cathode spacing

Also Published As

Publication number Publication date
DE1805460A1 (de) 1969-05-22
GB1224760A (en) 1971-03-10
FR1604383A (hu) 1971-11-08
BE705921A (hu) 1968-04-30
BE706879A (hu) 1968-05-22
NL6814586A (hu) 1969-05-02

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