US1790249A - Electrode for electrolytic cells - Google Patents

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Jan. 27, 1931. K. ROTH ELECTRODE FOR ELECTROLYTIC CELLS 2 Shegts-Sheet 1 INVENTOR Karl R025 0. TTORNEYS Original File d Jan. 21, 1926 Jan. 27, 1931. K. ROTH ELECTRODE FORELECTROLYTIC CELLS 1926 2 Sheets-Sheet 2 Original Filed Jan. 21

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KARL ROTH, or LUDWIGSHAFEN-ON-THE-RHI1\TE, GERMANY, AssIGNoR 'ro I. e. FAB;

immunesrRmmKrIENeEsELLscHArr, or FRANKFORT-ON-THE-MAIN, GERMANY,

A con'ronerron or GERMANY ELECTRODE FOR ELECTROL Y'JJIG CELLS Original application filed January 21, 1926, Serial No. 82,761, and in Germany January 22, 1925. Divided and this application filed February 7, 1928, Serial No. 252,586. Renewed July 15, 1930.

The present inventionrelates to electrodes for the electrolytic development of gases, especially by the decomposition of water The subject-matter of this application has been divided out from my copend-ing applicat on Ser. No. 82,761, filed Jan. 21, 1926. My improved electrodes have the advantage that the formation of foam from the electrolyte and the fine gas bubbles formedvis avoided to a great extent and units of high capacity can be constructed on a comparatively small floor area. My invention Will be explained with reference to the accompanying drawings which,

however, are diagrammatical and to which I do not wish to limit my invention.

Fig. 1 shows a vertical section of one'form of my improved electrode. Fig. 2 shows a front perspective View thereof partly broken away. Fig. 3 shows a vertical section of a modified form of my electrode. Fig. 4 is a front perspective .view of same. Figs. 5, 6 and 7 are vertical sectional views of some other modifications of my electrode.

The electrode according to my invention consists of a number of pockets an arranged one upon another in one or several series. The front-wall (b in Figure '1) of the pockets fronting the counter-electrode or the diaphragm between the two electrodes is made from metal provided with suitable openings to allow the passage of gas as for example borings or slits, or it may be made from Wireme sh. If both sides of the-electrode are to be used for electrolysis, either as a doublesideunipolar or as bipolar electrode, both the frontand back-walls of the pockets must be made of metal and permeable for the gases. If only one side is used for electrolysis the pockets arepreferably also made wholly of metal though this is not necessary.

The bulk of the gas is developed in the form of fine bubbles at the outer surface of the electrode, part of which directly passes through the openings of the electrode wall to-the interior of the pocket. The rest of the gas bubbles is forced into the interior by suitable guiding devices, for example by horizontal partitions it between the electrode :and the diaphragm z (see Figure 6) which at electrolyte.

the same time may serve as supports for the diaphragm. The partitions may be made of any material resistant to the action of the The distance between the said partitions and the upper edges of the' pockets may vary in accordance with the construction of the walls of the pockets.

The gases collected in each pocket are led ofi" through the upper wall of the pocket in any suitable manner, for example by pipes or channels, and are generally introduced into the next higher pocket. The said pipes or channels leading the gases off may have any desired cross-section, and preferably their lower end extends a little into the upper part of the lower pocket, the walls of which are correspondingly left, impermeable to gases in their upper part; By this construction, the fine gas bubbles rising within the pockets are forced to collect near the top of them to form a kind of gas cushion. As soon as additional gas causes said gas cushion toexceed the extension of the pipes or channels into the pocket, gas is discharged in the form' of big bubbles through all upper pockets: Thereby the formation of a very fine emulsion of the electrolyte with the fine gas bubbles is'prevented which not only would give rise to a foam, but would be liable to run backto the outside of the pocketand on account of its reduced conductivity would increase the resistance of the cell. As the quantity of gas increases from below to above, it may be advantageous to increase the number or the cross se'ction of the gas leading pipes or channels in the upper pockets. In some cases it appears c-onvenientnot-to pass the big gas bubbles successively through all of the upper pockets, but directly intothe uppermost one or tothe collecting pipe whether by means of pipes running outside saidpockets' in the spaces between the pockets or through the said spaces themselves, or for example'by prolonged pipes or channels directly running through several of thesepockets as indicated in Figure 7. i e

- When gas is discharged from the cushion in a pocket, the bubbles drag along considerable quantities of the electrolyte contained in that pocket. The resulting vacuum causes be made of one piece with the 5 suitable pipes or channels 7 and g which must not necessarily connect vertically ad- .xjacent pockets. It may be desirable to connect more remote pockets by means of such 'pes and g which may be led between or bin or through adjacent pockets (seem .in Figure 7 a a By a suitable arran ement and size of the pipes or channels o y small quantities of the'emulsion formed of fine gas bubbles and electrolyte are allowed to pass to upper or lower pockets, and moreover a continuous circulation of the electrolyte in all pockets and thereby a uniform concentration of the electrolyte is produced.

-The. exchange of concentration between anolyt'e and catholytemay be assisted by arranging the anode pockets and cathode pockets fronting one diaphragm in a vertically staggered relation to .each other.

The uppermost pockets may be, built as chief gas collecting chambers (see Figures 2 and 4). For this purpose, the upper arts of their side walls must be impermeable to for nearly any desired capacity by assembling the required number of pockets in ver-' tical and horizontal direction without encountering the difiiculties that would be caused with other cells by enlarging their size.

The electrodes may be constructed in many different ways. -Instead of using one layer of pockets, there may be two layers w1th their 'backsides against each other (see Fi es 3 and 4) so as to obtain a double-side v. electrode (Figures 4' and 7) which may be used as a unipolar or as a bipolar electrode. In the latter case, care must be taken that the electrode alsosecures aseparation of the electrolytes and gases of the two adjacent compartments which may be efiected by suitable tightenings k (Figure 7) between the pockets.'

The pockets of one electrode can be made, all or in groups, of one or a few single ieces of a metal, for example of a casting. The front walls, of perforated sheet-metal or of wire-mesh or the like are put on the said pockets afterwards and connected there-' to metal to metal to secure good electric conductivity. By this manner of producing 1 the electrode of one or a few single pieces to of metal the metallic contact of the front walls with the source of current isv easily efiected. Y v

the case of bipolar electrodes the tightening walls between thefpockets may name. Douconsisting of a a number of poo ets by horizontal and vergas. I

The hereinbefore described electrode has the advantage that it may be built as a unit ble side-unipolar electrodes (Figures 5 and ,6) may be made of one layer of.pockets with perforated frontand back-walls so as to allow the gases to enter into the pockets.

Or, all pockets may be surrounded by a wall common to all which means an electrode reat chamber divided into tical walls. The horizontal walls are provided with pipes or channels, as described above, so as to form gas collecting rooms, and mayalso be provided with pipes for circulating the electrolyte exactly as when using separate pockets. Figure 6' shows one form .of such electrodes.

Automatic devices may be arranged for a supply of water to replace that consumed during the electrolysis so as to maintain a certain quantity of electrolyte in each cell. In order to enable a cooling which when working at great outputs may become necessa'ry, suitable hollow spaces are provided in or between some of the pockets apart from the room containing the electrolyte and filled with a cooling liquid.

I do not claim in this claimed in the aforesaid original application Ser. No. 82,761. 7

What I claim 1. A double side unipolar electrodefor application my -new or improved electrode generically nor bipolar electrodes specifically, such being the development of gases, which consists-in l a structure comprising a number of pockets arranged one u on another and having permeable metal rontand back-walls and connection pipes between the pockets for pocket.

leading the gases upwards which pipes exv tend a little into the upper part 0 alower 2. A double-side unipolar electrode for the development of gases, which consists in a structure comprising a number of pockets per-= e arranged one upon another and ha meable metal frontand back-walls an connection pipes between the pockets for leading the gases upwards which pipes extend a little into the upper part of a lower pocket, and separate pipes for circulating the electrol 3. A dou le-side unipolar electrode for the development of gases, which consists in a structure comprising a number of pockets arranged one upon another and having permeable metal frontand back-walls and connection pipes between the pockets for leading the gases upwards which pi s extend a little mto the upper part o a lower pocket, and separate pipes for circulating the electrolyte, 'the upper edge of the front and back-walls of each pocket being provided with a guiding device forcing gas bubbles into the interior of the pocket.

4. A. double-side unipolar. electrode for the development of gases, which consists in a structure comprising a number of pockets arranged one upon another and havin permeable metal frontand back-walls an connection pipes between the pockets for leadin the ases upwards whlch pi extend a 'ttle into the upper part a lower pocket, and separate pipes for circulating my hand.

the electrolyte the upper art of the front: wall of the highest 00 et of a vertical series being impermea le to gas.

5. A double-side unipolar electrode for the development of gases, which consists in a structure comprisin a frame divided by partitions into a num er of pockets having permeable metal frontand back-walls and connection pipes between the pockets for leading the gases upwards which pipes extend a little into the upper part of a lower pocket.

In testimony whereof I have hereunto set' KARL ROTH.

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