US3287251A - Bi-polar electrochemical cell - Google Patents

Description

Nov. 22, 1966 y F. H. HORNE x-:TAL 3,287,251

BI-POLAR ELECTROCHEMICAL CELL Filed April 2, 1962 United States Patent O 3,287,251 BI-POLAR ELECTROCHEMICAL CELL Frederick H. Horne, 541 Prospect, Lake Bluff, Ill., and Robert Blevitzky, Evanston, Ill.; said Blevtzky assignmto said Horne Filed Apr. 2, 1962, Ser. No. 184,355 5 Claims. (Cl. 204-270) The invention is directed to an improved bi-polar electrochemical cell for fluid electrolysis involving simultaneous production of ya liquid product and a gaseous product. More particularly, the invention provides an unusually ellicient means ttor electrolysis of uids at atmospheric pressure, under vacuum or under pressure, and simultaneous removal and separation of gases formed in or brought into the cell, by causing fluid to pass through the cell which, acting on the uid, forms a liquid product and gaseous product in separate form .and in high purity.

Another object orf the invention is to provide an electrolytic cell `apparatus to process all or part of a fluid stream under pressure or vacuum in a conduit by means of interposing the cell in the path of said stream, or by means of admitting a portion of the uid to the cell and returning the cell liquid product to the conduit, and venting the gases formed or brought into the cell to the atmosphere or to a suitable gas container or to said conduit.

Another object of the invention i-s to provide an apparatus of simple, compact modular construction which is readily and economically adaptable to various electromechanical processes and Various electric current supplies and potentials.

Another object is to provide an apparatus to increase the current, power and material eiciency of an electrochemical process by increasing the apparent density of the uid undergoing electrolysis, through removal of the gaseous products from each cell chamber and returning de-entrained iluid to said cell chamber.

A further object of the invention is to provide a lai-polar cell apparatus which is adaptable for electromechanical processing of noxious, poisonous, corrosive or radioactive fluid or lluids becoming noxious, corrosive or poisonous or radioactive when processed electrochemically.

A further object of the invention is to provide an electrolytic cell apparatus which may be fixed or portable and which is adaptable for attachment yto a pressurized conduit handling a fluid containing for example, lsoluble halides, and electrolyzing such halides to produce hypohalites or halates.

Many other objects and advantages will be apparent to those xskilled in the art from the disclosure herein given.

In one application of this invention, using a pressurized sodium chloride solution of approximately 5% by weight, we have produced lsodium hypochlorite solutions at 75 p.s.i. bearing about 2% by weight available chlorine and less than 50 parts per million sodium chlorate, and using a total potential of 117 volts direct current of 21/2 amperes, and using electrodes of the character described in our copending application. Hydrogen gas formed in the bipolar cell was produced free of entrained electrolyte and was safely vented to the atmosphere.

In another application orf our invention, by using a pressurized salt pot feeder, We were able to chlorinate a stream of water to concentrations of 0.1 -to 500 parts per million using a variable voltage source. The apparatus also may be attached and used effectively for the method described in Ferris Patent No. 2,873,23 6, issued May 10, 1951.

The invention may be employed eectively in an electrochemical process requiring the use of different anode and cathode material as in sodium chlorate production,

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by using iron cathodes and graphite anodes of the character described in our copending application.

In the drawings, wherein like reference characters indicate like or corresponding part-s:

FIG. l is a perspective view 0f a unit or assembly embodying our invention.

FIG. 2 is a sectional view taken4 approximately on the line 2 2 of FIG. 3;

FIG. 3 is a sectional view taken approximately on the line 3 3 of FIG. 2;

FIG. 4 is a sectional view of a single cell element taken approximately on lthe line 4 4 of FIG. 3;

FIG. 5 is a sectional view taken approximately on the line 5 5 of FIG. 2; and

FIG. 6 is a [sectional View taken approximately on the line 6 6 of FIG. 2.

In general, the apparatus is of modular construction, comprising a body or housing structure rformed from a plurality of plate-like elements 1, suitably stacked or assembled with respective end elements 2 and 3 and secured in assembled relation between respective compression plates 4 and 5, by connecting bolts 6 and cooperable nuts 7.

Extending through openings in the respective compression plates 4 and 5 and operably secured to the adjacent end elements 2 and 3 are respective conduits 8 and 9, the conduit 8 being designated as a fluid inlet and the conduit 9 as a iluid outlet. Also operatively connected to the end element 2 is a conduit 11 for the discharge of liberated gas.

Each element 1, as illusrtated in FIGS. 2, 3, 4 and 6, is provided with respective disc-like electrodes 12 and extending from the endmost elements 1 are respective terminals 12 and 14 operatively connected to the associated electrode 13 lby means of which a source of electric current may be operatively connected to the assembly.

Each element 1, as illustrated in FIGS. 3 and 4, and the end plates 2 and 3 are formed from a suitable nonconductive material which preferably is resistant to corrosion by fluids involved and depending upon the nature of the particular operation to be elTected, material such as concrete, ceramic clays, thermo-setting or thermoplastic polymers, either virgin, lilled or laminated, and other molded or machineahle materials may be employed.

As hereinafter discussed in details, electrolyte lluid is adapted to be admitted to the unit through the conduit 8, passing into the adjacent cell formed by the end plate 2 and adjacent element 1 from which the uid passes to the succeeding cells through openings 15 in each electrode 12, and finally discharged from the conduit 9. As a result of the connection of a source of current to the terminals 13 and 14, current will flow between the electrodes to partially electrolyze the luid in the cell cavities and any gas formed during such electrolysis will be suitably col-- lected and discharged through the conduit 11.

In assembly of the apparatus a suitable number of elements 1 are coupled with interposed gaskets 16 and to form a bi-polar cell apparatus of suitable predetermined voltage drop .and electrolyte conversion capacity. In operation of our invention electrolyte flowing through the cell cavity is thus subjected to a direct current and gases during electrolysis, and any entrained electrolyte forming a froth, is carried upward through suitable froth inlet ports 17. The gas-liquid mixture impinges on bailles 1S and 19 causing separation into a gaseous component which ows out via gas port 21, and a liquid component which re turns via electrolyte return port 22 and return groove 23 to the cell cavity at 24.

Ribs 25 Iserve the dual purpose of guiding the 'froth llow and strengthening the tcell element. Each cell section is vsuitably sealed to the subsequent section by means 3 of the gasket 16 which is inserted in cooperable grooves 26.

FIG. 5 illustrates the end element or plate 3 of the apparatus to which conduits 9 and 11 are connected. Fluid ports 27 and conduit 9 permit flow of electrolyte, with gas port 21 communicating with conduit 11. Gasket groove 11 is olf identical configuration as in cell element 4 of FIG. 2 and permits sealing ofl` of the cell assembly. The end element 2 is of corresponding construction, either omitting the port 21 or having the same plugged.

FIG. 4 illustrates the details of the construction of the electrical terminals 13 and 14. More specifically each terminal is attached to the first or the last electrode 12 of the apparatus by means of terminal bolt 28 which screws into the wall of the associated cell element and thence into the electrode 12 to make an electrical contact. A liquid tight seal is maintained by using seal gasket 29, bushing 31, gasket 32, washer 33 and compression nut 34 which compresses the gaskets 29 and 32 in a pressure tight manner, thus preventing leakage of uid along the threads of bolt 28. The remainder of bolt 28 is sufficiently long to permit attachment of an electrical cable lug 3S by means of washer 36 and nut 37. In the attachment of bolt 28 to the electrode 12, it may be desirable that the leading edges of the bolt 28 be self-tapping or fluted to assist in establishing good electrical contact with the electrode 12.

Referring to FIG. 2, electrolyte enters the cell cavity via conduit 8 and port 15 in the first electrode 12. The liquid then passes downward through the cell cavity, through the electrode port 15 in the adjacent electrode 12. and into the next cell cavity bounded by bi-polar electrode 12 on the left. The vertically reversing ow continues to the last cavity and out through outlet conduit 9.

To secure eflicient cell operation, froth formed in the cell cavities during electrolysis should be removed. This removal or separation is facilitated by the bailles 18 and 19, which, with the webs 17 and the channel or grooves 23, form a de-entrainment section in the upper portion of each cell element. De-entrainment proceeds by means of impingement of the froth on the batiles and by means of contact of the froth with separated liquid. Separated electrolyte liquid is returned through ports 24 to the cell cavity from whence it came without dilution with liquid from different cell cavities. Removal of froth and accumulating gases from the cell cavity increases the bulk density of the electrolyte in the cavity and increases electrolyte conductivity which in turn increases the overall cell voltage efiiciency and power eficiency.

Separated gas passes through ports 21 in cell element 1 and thence out through port 21 and conduit 11. Also by means of rapid and efficient separation of electrolyte from the froth and return of such electrolyte to the cell cavity, maximum electrolytic conversion of the electrolyte entering the apparatus is realized. Such return is effected by means of the hydrostatic head of the separated electrolyte just above return port 22, illustrated in FIG. 3.

Each bi-polar electrode 12, containing port 15, preferably rests against a gasket 38 with sufficient pressure to maintain a seal equal to or greater than the dynamic pressure drop from cell cavity to cell cavity. Electrodes may be of metal, non-metals, impregnated or coated nonmetallic materials. It will be understood by those skilled in the art from the compressibility of gasket 38 and the thicknesses of electrodes 12 will be governed in part by cell operating pressures and electrode strength.

As electrolyte passes through the apparatus it is discretely converted in part in each cell cavity C until it reaches the last or outlet cavity 3 formed by the last cell element 1 and adjacent element 3. By means of addition or subtraction of cell elements 1 and associated electrode 12, the parameter of voltage drop can be controlled at constant current density, thus enabling operation of an electrochemical process at the highest efficiency. The

modular construction of the cell elements also permits simple and economical manufacture of cells for widely varying voltage supplies. Only the rst and last electrodes 12 of the apparatus need be directly connected to the electric power supply. It is known, however, by those skilled in the art that the electrode may be ,connected in a series parallel bi-polar arrangement by addition of more terminals at intermediate electrodes of the apparatus and connection of terminals in a series parallel manner.

Each cell element 1 contains gasket grooves 26 on both faces and each conduit connector or end element 2 and 3 contains gasket grooves on the liquid face. In assembling the apparatus embodying our invention, continuous O-ring or groove gaskets 16 are inserted in the grooves 26 and each element and connector plate is placed in juxtaposition. The sub-assembled apparatus is subsequently compressed with metal compression plates 2 and 6 by tightening compression bolts 6 and nuts 7. Flat or full face gaskets may be substituted for groove gaskets 16 by substitution lof flat gasket faces on cell elements 1,`

and end elements 2 and 3. Non-metallic end or compression plates may be used for environments where metals are not desirable.

As previously mentioned, each electrode 12 is engaged with an associated gasket 38 on the shoulder 39 of the cell element. sembly of the apparatus is sufliciently compressible so that the `outer surface of the electrode 12 may be disposed `in the same plane as the vertical surface of the cell elements.

Electrodes 12 and the cell cavity portion of each cell element 1 are preferentially cylindrical in shape for purposes of achieving highest mechanical strength; however, it is feasible and practical to use rectangular, elliptical or other shapes. Certain electrodes are preferred for specific electrochemical processes conducted in the apparatus described. For example, we have found that production of hypohalite solutions is best carried out using graphite electrode on which platinum has been deposited.

Also, halate solutions are very efficiently produced in apparatus embodying our invention using a laminated platinum foil graphite electrode.

From the above description of our invention, it is seen that the invention clearly provides means to efficiently electrolyze a fluid under all conditions of pressure, tem-` perature, concentration, flow rate, voltage and current density, while automatically maintaining the electrolyzing solution in the best state for the highest yield of` cell product coupled with high overall economy.

The invention also provides simple means for carrying out electrolysis of a uid in a bi-polar cell where noxious or harmful cell products or fluids must be completely sealed off from the ambient environment. Means are also provided by the invention for froth separation in each compartment enabling operation at very high cell ow rates and high material efficiencies.

Having thus described our invention, it will be obvious to those skilled in the art from the disclosure herein given that various immaterial modifications may be made in the same without departing from the spirit of our invention; hence we do not Wish to be understood as limiting ourselves to the exact form, construction, arrangement and combination of parts herein shown and described or uses mentioned.

What we claim as new and desired to secure by Letters Patent is:

1. A bi-polar multi-cell electrochemical apparatus for fluid electrolysis, comprising a housing having an inlet and an outlet therein, the housing being constructed to form a uid path operatively connecting said inlet and outlet for the passage of fluid through the housing, a plurality of flat, substantially plate-like modular elementsr Gasket 38 when compressed 'during as.`

including disc-like electrodes interposed in spaced relation in said fluid path and forming a plurality of individual cells operatively connected in series, means for connecting the outermost electrodes to a current supply source, said housing constructed in the form of modular elements operatively disposed between spaced end elements, said modular elements each including a disc-like electrode provided with an opening carried thereby through which the fluid for iluid electrolysis passes to the succeeding cells through openings in each of said disc-like electrodes, each modular element provided with oppositely disposed substantially parallel end faces each adapted to abut an adjacent element, said end faces being constructed to receive and cooperate with gasket means disposed between abutting end faces to eiect a fluid-tight seal therebetween, means operatively connected to each cell for withdrawing liberated gas therefrom, said means for withdrawing liberated gas comprising a de-entraining chamber including baie means associated with each cell provided with a gas port and operatively communicating therewith for the separation of liberated gas from the liquid and oth, said housing provided with a uid passage therein for each de-entraining chamber operatively communicating with liquid in such cell to eiect a liquid return from said chamber to said liquid.

2. A bi-polar multi-cell electrochemical apparatus for uid electrolysis, comprising a housing having an inlet and an outlet therein, the housing being constructed to form a lluid path operatively connecting said inlet and outlet for the passage of fluid through the housing, a

plurality of flat, substantially plate-like modular elements y including disc-like electrodes interposed in spaced relation in said uid path and forming a plurality of individual cells operatively connected in series, means for connecting the outermost electrodes to a current supply source, said housing constructed in the form of modular elements operatively disposed between spaced end elements, said modular elements each including a disc-like electrode provided With an opening through which the uid for iiuid electrolysis passes to the succeeding cells through openings in each of said disc-like electrodes, each modular element provided with oppositely disposed substantially parallel end faces each adapted to abut an adjacent element, said end faces being constructed to receive and cooperate with gasket means disposed between abutting end faces to elect a Huid-tight seal therebetween, means operatively connected to each cell for withdrawing liberated gas therefrom, said means for withdrawing liberated gas comprising a de-entraining chamber including baffle means associated with each cell provided with a gas port and operatively communicating therewith so that the gas-liquid mixture impinging on the bafe means causes separation into a gaseous component which flows out through a gas port provided in each plate-like modulor element and operatively connected with each cell cavity formed by said spaced plate-like modular elements, and a liquid component which returns by an electrolyte passage means provided with a return port and a return groove to the cell cavity, each modular element compris-V ing a body member of a material that is relatively inert to the iiuids with which it is to be employed, said body member having substantially parallel end walls adapted to abut like end walls of like adjustment cooperable body members, said body member having an annular-shaped portion, the inner periphery of which is provided with an inwardly extending shoulder, the associated disc-like electrode having substantially parallel faces and of a configuration to be received in and supported by said annularshaped portion with one disc-like electrode face disposed substantially in the plane of the adjacent end wall of the body member and the other face inwardly spaced from the opposite end wall, operative with the adjacent modular element to define a cell space therein, and each body member provided with means including said bafile means and rib means providing froth inlet ports and integrally formed therewith and cooperable with an adjacent body member similarly formed to provide the de-entraining chamber associated with each successive cell space operatively connected together.

3. A bi-polar multi-cell electrochemical apparatus for uid electrolysis, comprising a housing having an inlet and an outlet therein, the housing being constructed to form a iluid path operatively connecting said inlet and outlet for the passage of fluid through the housing, a plurality of flat, substantially plate-like modular elements including disc-like electrodes interposed in spaced relation in said iiuid path and forming a plurality of individual cells operatively connected in series, means for connecting the outermost electrodes to a current supply source, said housing constructed in the form of modular elements operatively disposed between spaced end elements, said modular elements each including a disc-like electrode provided with an opening through which the lluid for uid electrolysis passes to the succeeding cells through openings in each of said disc-like electrodes, each modular element provided with oppositely disposed substantially parallel end faces each adapted to abut an adjacent element, said end faces being constructed to receive and cooperate with gasket means disposed between abutting end faces to effect a fluid-tight seal therebetween, means operatively connected to each cell for withdrawing liberated gas therefrom, said means for withdrawing liberated gas comprising a de-entraining chamber including baille means associated with each cell provided with a gas port and operatively communicating therewith so that the gas-liquid mixture impinging on the bae means causes separation into a gaseous component which flows out through a gas port provided in each plate-like element and operatively connected with each cell cavity formed by said spaced plate-like modular elements, and a liquid component which returns by an electrolyte passage means provided with a return port and a return groove to the cell cavity, each modular element comprising a body member of a material that is relatively inert to the fluids with which it is to be employed, said body member having substantially parallel end walls adapted to abut like end walls of like adjustment cooperable body members, said body member having an annular-shaped portion, the inner periphery of which is provided with an inwardly extending shoulder, the associated disc-like electrode having substantially parallel faces and of a configuration to be received in and supported by said annular-shaped portion with one disclike electrode face disposed substantially in the plane of the adjacent end wall of the body member and the other face inwardly spaced from the opposite end wall, operative with the adjacent modular element to define a cell cavity therein, each body member provided with a portion adjacent the associated disc-like electrode cooperable when disposed adjacent a like portion of a similar modular element to form the aforesaid de-entraining chamber operatively communicating with said cell cavity.

4. As an article of manufacture, a modular cell section for use in uid electrolysis, comprising a plate-like element of a material that is relatively inert to the fluids with which it is to be employed, said plate-like element including substantially parallel end walls adapted to abut Y like end walls of similar plate-like elements, and formed with an annular-shaped portion, the inner periphery of which is provided with an inwardly extending shoulder, a disc-like electrode provided with an opening therein for the passage of fluid from one side of the electrode to the other side thereof, said electrode being formed with substantially parallel faces and of a configuration to be received in and supported by said annular-shaped portion with one electrode face disposed substantially in the plane of the adjacent end wall of the plate-like element and the other face inwardly spaced from the opposite end wall, operative to form a cell space therebetween, said platelike element provided with a portion adjacent said disclike electrode and cooperable when disposed adjacent a like portion of a similar section to form a de-entrainment chamber operatively communicating with said cell space, means carried by said plate-like element forming bales for said de-entrainment chamber, and said plate-like element provided with a passageway therein and operatively connecting said de-entrainment chamber with the cell space at a point spaced from the connection thereof with said de-entrainment chamber for the return of uid from the latter to said cell space, and the side walls of said plate-like element provided with respective grooves therein disposed adjacent the peripheral edges thereof and of a size to receive an endless gasket member for effecting a seal between assembled cell sections.

5. As an article of manufacture, a modular cell section for use in Huid electrolysis, comprising a plate-like element of a material that is relatively inert to the fluids with which it is to be employed, said plate-like element including substantially parallel end Walls adapted to abut like end walls of similar plate-like elements, and formed with an annular-shaped portion, the inner periphery of which is provided with an inwardly extending shoulder, a disc-like electrode provided with an opening therein for the passage of fluid from one side of the electrode to the other side thereof, said electrode being formed with substantially parallel faces and of a configuration to be re ceived in and supported by said annular-shaped portion with one electrode face disposed substantially in the plane of the adjacent end wall of the plate-like element and the other face inwardly spaced from the opposite end wall, operative to form a cell space therebetween, said plate-like element provided with a portion adjacent said disc-like electrode and cooperable when disposed adjacent a like 'portion of a similar section to form a de-entrainment chamber operatively communicating with said cell space, means carried by said plate-like element forming bales for said de-entrainment chamber, said plate-like element provided with a passageway therein and operatively connecting said de-entrainment chamber with the cell spaced at a point spaced from the connection thereof with said de-entrainment chamber for the return of fluid from the latter to said cell space, said plate-like element provided with an electrical connecting terminal extending through the edge of said plate-like element and in current conducting engagement with said disc-like electrode, and said terminal comprises an externally threaded member threaded into said plate-like element and partially into said disc-like electrode.

References Cited by the Examiner UNITED STATES PATENTS 522,839 7/1894 Knoer 204-268 892,983 7 1908 Digby 204-220 968,492 8/ 1910 McDorman 204-268 1,292,024 1/ 1919 Niswonger et al 204-268 1,397,239 1 1/ 1921 Slater 204-228 1,996,799 4/ 1935 Evans 204-275 2,191,574 2/ 1940 Martin 204-238 2,862,864 12/ 1958 Berghaus 204--256 2,873,236 2/1959 Ferris 204-95 FOREIGN PATENTS 28,353 12/ 1902 Great Britain.

400,247 10/ 1933 Great Britain.

745,048 2/ 1956 Great Britain.

202,238 4/ 1939 Switzerland.

JOHN H. MACK, Primary Examiner.

D. JORDAN, Assistant Examiner.

Claims (1)

1. A BI-POLAR MULTI-CELL ELECTROCHEMICAL APPARATUS OR FLUID ELECTROLYSIS, COMPRISING A HOUSING HAVING AN INLET AND AN OUTLET THEREIN, THE HOUSING BEING CONSTRUCTED TO FORM A FLUID PATH OPERATIVELY CONNECTING SAID INLET AND OUTLET FOR THE PASSAGE OF FLUID THROUGH THE HOUSING, A PLURALITY OF FLAT, SUBSTANTIALLY PLATE-LIKE MODULAR ELEMENTS INCLUDING DISC-LIKE ELECTRODES INTERPOSED IN SPACED RELATION IN SAID FLUID PATH AND FORMING A PLURALITY OF INDIVIDUAL CELLS OPERATIVELY CONNECTED TO A CURRENT SUPPLY SOURCE, SAID THE OUTERMOST ELECTRODES TO A CURRENT SUPPLY SOURCE, SAID HOUSING CONSTRUCTED IN THE FORM OF MODULAR ELEMENTS OPERATIVELY DISPOSED BETWEEN SPACED END ELEMENTS, SAID MODULAR ELEMENTS EACH INCLUDING A DISC-LIKE ELECTRODE PROVIDED WITH AN OPENING CARRIED THEREBY THROUGH WHICH THE FLUID FOR FLUID ELECTROLYSIS PASSES TO THE SUCCEEDING CELLS THROUGH OPENINGS IN EACH OF SAID DISC-LIKE ELECTRODES, EACH MODULAR ELEMENT PROVIDED WITH OPPOSITELY DISPOSED SUBSTANTIALLY PARALLEL END FACES EACH ADAPTED TO ABUT AN ADJACENT ELEMENT, SAID END FACES BEING CONSTRUCTED TO RECEIVE AND COOPERATE WITH GASKET MEANS DISPOSED BETWEEN ABUTTING END FACES TO EFFECT A FLUID-TIGHT SEAL THEREBETWEEN, MEANS OPERATIVELY CONNECTED TO EACH CELL FOR WITHDRAWING LIBERATED GAS THEREFROM, SAID MEANS FOR WITHDRAWING LIBERATED GAS COMPRISING A DE-ENTRAINING CHAMBER INCLUDING BAFFLE MEANS ASSOCIATED WITH EACH CELL PROVIDED WITH A GAS PORT AND OPERATIVELY COMMUNICATING THEREWITH FOR THE SEPARATION OF LIBERATED GAS FROM THE LIQUID AND FROTH, SAID HOUSING PROVIDED WITH A FLUID PASSAGE THEREIN FOR EACH DE-ENTRAINING CHAMBER OPERATIVELY COMMUNICATING WITH LIQUID IN SUCH CELL TO EFFECT A LIQUID RETURN FROM SAID CHAMBER TO SAID LIQUID.

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