US2599363A - Electrolytic cell - Google Patents

Description

June 3, 1952 A. BENNETT El'AL ELECTROLYTIC CELL Filed June 2, 1949 Inventors V ALFRED BE-NNET F163 DONALD HENRY 'PR INCE GEORGE ERNEST EDWARDS Attorney-s Patented June 3, 1952 g UNITED STATES PATENT OFFICE assasss ELECTROLYTIC CELL 'Alfred Bennett and Donald Henry Prince, Widnes, and George Ernest Edwards, Runcorn, England, assignors to Imperial Chemical Industries Limited, a corporation of Great Britain Application June 2, 1949, Serial No. 96,798 In Great Britain June 4, 1948 Claims.

This invention relates to improvements in electrolytic apparatus, in particular cells for the electrolysis of solutions of alkali metal salts.

Many forms of apparatus have been proposed or are employed for the electrolysis of solutions of alkali metal salts. One type of such apparatus which has found extensive use comprises a trough-shaped vessel having a smooth plane bottom, long in comparison with its width, and arranged to be at a slight angle to the horizontal so that a mercury cathode can be flowed thereon. In cells of this type the anodes, normally of graphite, are fixed on conducting rods which pass through the cover of the cell. The under surfaces of the'graphite anodes are so arranged that they are parallel to and a short distance from the mercury cathode. As electrolysis proceeds disintegration or wear of the graphite anodes takes place, chiefly on the under surface thereof, making necessary periodic readjustment of the position of the anodes in order to maintain the efiiciency of the process which is impaired by the increased interelectrode gap resulting from disintegration of the anode under-surface. A number of means are known for efiecting the required periodic adjustment of anode position in flowing mercury cathode cells. Disadvantages associated with such means are: the process must be stopped while the adjustment is being.

carried out; the gas-tightness of the cell is broken at each adjustment; each anode mass is provided with separate adjusting means, a fact which makes the operation of the means cumbersome and time consuming. In some of the known adjusting means one or other of these disadvantages may be absent, but in none of them are all three overcome.

The present invention has for its object the provision of means for the simultaneous adjustment of all the anodes of a cell of the flowing mercury cathode type, or of convenient groups of the said anodes without interruption of the electrolytic process or breaking of the gas-tightness of the cell.

The adjusting means according to the invention, comprise a rigid carrier located above the cover of the cell and adapted to have its position adjusted in a vertical direction, the anode blocks or masses being attached to the said carrier by means of electrically-conducting rods or tubes which pass through apertures in the cell cover and are flexibly sealed to the edges of the said apertures.

In a preferred form of our invention copper tubes, suitably protected from the products of electrolysis, supporting the anode blocks are carried by two copper bars located above the cell lid and running along the length thereof. The said copper bars are carried on a series of T-bars set at right angles to the cell length. Adjustment of the height of the carrier bars, and consequent- 2 1y of the anode blocks as a whole, is achieved by means of threaded pillar bolts which pass through lugs or flanges at the ends of the cross T-bars beforementioned at several convenient intervals along the length of the cell. Diaphragms of polychloroprene rubber, sold under the trade name Neoprene, or like flexible material, are secured by suitable means to the rods or tubes carrying the anode blocks and to the edges of the apertures in the cell cover through which the said rods or tubes pass. Although it is not an essential feature of our invention, the carrier bars may be employed to convey the electric current to the conducting rods or tubes supporting the anode blocks.

Variants of our invention which are envisaged include the supporting of groups of anode masses by carrier bars extending only along a suitable subdivision of the total length of the cell and the replacement of the individual flexible sealing means at each anode supporting rod or tube by a flexible seal extending round the entire periphery of the cell lid and secured thereto and to the Walls of the lower part of the cell. In the case of the latter variant, non-flexible sealing secures the gas-tightness of the cell at the points at which the anode supporting rods or tubes-pass through the cell cover.

An embodiment of the invention is illustrated by way ofexample in the accompanying-drawings, which are not to scale and in which:

Figure 1 is a sectional elevation of a cell and anode adjusting assembly, according to the in.- vention, and

Figure 2 is a plan of the same cell and anode adjusting assembly, and

Figure 3 is a vertical, cross-sectional end view of a slightly modified form of cell and anode adjusting assembly. v H

In the figures similar parts bear similar reference numbers.

Referring to the drawings, the number I refers to an anode block or mass, normally formed of a suitably impregnated graphite, 2 a supporting tube or rod; 3, 3 the carrier rods located above the cell cover 5; 4 the T-bars suitably secured to the carrier rods and having holes in flanges at their ends engaging the pillar- bolts 8, 8; 6 a flexible diaphragm sealing the supporting rod 2 to the edge of a circular aperture in the cell cover.

In the illustrated embodiment the electric current may be conveyed to the anode blocks l by the attachment of suitable busbars either to the carrier rods 3, 3 or to the T- bars 4, 4. The number of T-bars is determined by the length of the cell and only small number of the T-bars have flanges with holes engaging pillar-bolts.

In the slightly modified form of the cell and anode adjusting assembly shown in Figure 3, relative movement between anodes I and the -.cell base i is permitted by the flexible sealing 3 diaphragms 6,. These diaphmgms ,6 consist of thin, flexible, sheet material, for example, neoprene, or thin sheet metal, protected from attack by the products of electrolysis by meansoi resisting coatings.- The diaphragms 6 arebol'ted around their lower edge to thercell cover 5, while the apexes of the diaphragms .6 surround and flexibly seal the support'ng 'rods -2. The 'aper tures H which the diaphragms surround and which extend through the cell cover '5, have conically countersunk upper portions, thus providing for maximum relative movement between anodes I and cell base .1.

In this latter form of cell, the T-bars 4 are slightlymodifled in shape from .those employed in the :cells illustrated in Figures 1 and I2. and the-cell base I has lining material 9 on the walls thereof with the cell cover S'being sealed :to the oellbase 1 by the solid seal l0.

Since -many changes may be made in 'the details and illustrations set :forth above without :departing from the spirit and scope of the invention, 'it is to be understood that the invention -is not limited to such details except as indicated in the appended claims.

We claim:

'1. An electrolytic cell comprising in combination a trough-shaped vessel having .a smooth plane bottom, long in comparison with its width, arranged at a slight angle to the horizontal so that mercury cathode can be flowed thereon, a cover therefor, said cell cover provided with apertures, the upper portions of which are conical-1y countersunk, a plurality of graphite anodes distributed uniformly along the inside of said vessel supported in an elevated position above said plane bottom by means for simultaneous adjustment of a plurality of said anodes all at one time, said adjustment means comprising metal-lie rods running -in a direction parallel 'to the length of the cell and fixed to cross bars at right angles to the cell length, the cross bars having at their ends vertical holes through which pass threaded pillars bolts provided with adjusting nuts, the anodes masses being secured to said metallic rods by a series of rigid metal rods which pass through said apertures in the cell cover and sealing means providing for vertical relative movement between said cell cover and said anodes without escape of gas from within said vessel comprising flexible diaphragms secured at their peripheries to said cell cover apertures and said diaphragms surrounding said conducting rods and being in fluid-tight engagement therewith.

2. An electrolytic cell comprising in combination a trough-shaped vessel having 'a smooth plane bottom, long in comparison with its width, arranged at a slight angle to the horizontal so that a mercury cathode can be flowed thereon,

a cover therefor, said cell cover provided with apertures, the upper portions of which are conically countersunk, a plurality of graphite anodes distributed uniformly along the inside of said vessel supported in an elevated position above said plane bottom by means for simultaneous adjustment of a plurality of said anodes all at one time, said adjustment means comprising a carrier located above the cell cover the carrier being formed from parallel metallic rods running along'th'e length of the cell and metallic T-bars secured to the said parallel rods at right angles thereto at suitable intervals, the T-bars being furnished at their ends with flanges through --which pass holes engaging threaded pillar bolts projecting vertically upward fromthelower part of the cell, vertical adjustment of the position of the carrier being produced by suitable adjustment of nuts on the pillar-bolts, the said anodes being rigidly secured to said carrier by electrically-eonduc-ting rods, which rods are flexibly sealed Site the edges of said apertures in the cell cover :through which they pass by flexible diaphragmssecured at their peripheries to said cell cover-apertures and said diaphragms surrounding said :conduct'ing rods and being in fluid-tight engagement therewith.

3. An electrolytic cell comprising in combination a, trough-shaped vessel, long in comparison with its "width, a cover therefor, said cell :cover provided with apertures, :the upper portions of which are sonically countersunk, :and .a plurality oiamdes' distributed uniformly along the inside of said wessel supported in an elevated position above thezbottom of said vessel by means forthe simultaneous adjustment of .a .plm'ality of said anodes allat one time, said means :comprising a rigid :carrier located above said :cell cover and extending longitudinally thereof, said carrier being adjustable .a substantial distance :relative'to said cover ncrmal'to the plane of said cover, electrically-conducting trods connected to said rigid carrier passing through said openings .in said cover and being attached :to :said anodes, means for adjusting the vertical height of said rigid carrier, and flexible sealing diaphragms providing for vertical, relative movement between said :cell cover. :andsaid anodes without escape of gas from within said umSsLc-nmprising flexible diaphragm-s secured at their peripheries to said cell :cover -.openings ,and said diaphragms surrounding sairl conducting rodsand .beinginiluidtight engagement :themwith.

4. Means according to :claim 3 for the simultaneous adjustment of the height of convenient groups of the anode masses of an electrolytic cell of the :flowing mercury cathode type, and in which the vertical rods supporting the anode .masses are sealed to :theedges :of the apertures .in the cell cover by means of adiaphragms of polychloroprene;rnbber.

5. .-An electrolytic cell according to claim 3, and in which the anode supporting rods are sealed'to the edges 'of the apertures in the cell cover :by means of diaphragms of thin sheet ."metal pro-'- tected from attack by the products .of electrolysis by means of a resistant coating.

ALFRED BENNETT. DONALD HENRY PRINCE. GEORGE ERNEST EDWARDS.

REFERENCES CITED The following references are of record in the file of this patent:

.U'NI'Ii'IiD STATES PATENTS Number Name Date 667,498 Chapman ,Feb. '5; 1901 1,187,903 Greenawalt June 20, 1916 2,231,030 Scofield 'Feb. '11, 1941 2,328,665 Munson Sept. Fl, 1943 2,502,888 Ravenscroft Apr. :4, 1950 2,503,337 Hirsh et al Apr. 11, 1950 FOREIGN PATENTS Number Country Date 173,520 Germany July 26, 1906 OTHER REFERENCES Fiat, 'Final Report .816 (P. B. 33,22I), released September 13, 1946, pages 14, 18 and 22.

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