US2350669A - Electrolyzer cell - Google Patents

Description

June, 1944. V w, BIOLLER 4 2,350,669

` ELECTROLYZER CELL Filedl April 25) 1940 i y l'NvENToR,

HfzZheZm Bolle):

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Patented June 6, 1944 UNITED STATES ATENT OFFICE ELECTROLYZER CELL Application April 25, 1940, Serial No. 331,608 In Germany May 5, 1939' 2 Claims.

It is well known that the separation of gas in water decomposing apparatus takes place not within the individual electrolyzer cells, but generallyfor a whole battery. The return of the electrolyte from the collecting tank by way of the distributer to the individual cells is similar, each cell being connected to the distributer at a connecting point. In contradistinction to the ducts leading to the gas separator, in which the electrolyte flows with gas, diminishing the eiective cross section and therefore the electric conductivity, only the resistance of the pure electrolyte lling the ducts is present in the return pipe. As a function of the decomposition potential, there ows an electric shunt current, which on the one hand represents a considerable loss, on the other hand the unintended production of gas reduces the purity of the gas. These injurious inuences could be diminished only in an unsatisfactory manner by a number of commonly known means such as lining the walls of the ducts with insulating material, or subdividing the collecting line by means of electrically insulating intermediate rings.

The present invention concerns an electrolyzer cell with an external electrolyte circulation, in which the return of the electrolyte is effected by means of an electrically insulating intermediate member. According to the invention, the proportion of the length of the insulating intermediate member to the cross section of its bore is so chosen that the impurities of the gases produced in the apparatus in consequence of the shunt caused by the returned electrolyte, does not exceed a definite maximum value (e. g. 1/2%) In order to be able to return a sufficient quantity of electrolyte, a substantially greater pressure is needed than is used in present designs. This pressure, which according to experience is 1/4 and more above atmospheric, is produced by means of a pump.

Devices it is true, are known in which the resistance of the entering column of electrolyte is increased by means of a nozzle greatly diminshing the cross section. The effect of this means is however limited, because it is proposed to increase resistance by diminishing the cross section and not by simultaneously greatly lengthening the column of liquid.

The diagrammatic drawing shows a form of embodiment of the subject matter of the invention, Fig. 1 showing the electrolyte supply in a block of several cells and, in Fig. 2, shown in a single element on a larger scale. I are the electrolyzer cells connected in series. The electrolyte is fed through the distributer 2 to the intermediate member 3, which connects the cell to the distributer 2. The intermediate member consists of an electrically insulating material, preferably glass, and has a narrow bore 4 in the longitudinal axis. On the one hand it is connected gas tight to the distributer by a commonly known means, and on the other hand it is carried through the wall of the cell by means of a solution tight passage. By suitably selecting the length L and the cross section 9 of the bore 4, the resistance L R--q9 can be raised to the required degree, q being the specio resistance of the electrolyte. The resistance can be increased so much that the disturbing influence of electric shunts can be kept down to any desired amount. In order to force the electrolyte in a suicient quantity through the narrow bore 4, it is subjected to excess pressure, e. g., by means of a centrifugal pressure pump.

Having thus described my invention I claim:

l. An electrolyzer cell for gas separation by water decomposition having the combination of means for externally circulating its electrolyte including a conduit for returning the electrolyte to the cell, said conduit including a tube of electrical insulation material having an extremely narrow bore with proportionately enhanced length w for producing sufciently high electrical resistance to prevent formation of the shunt currents that are responsible for causing gas impurities in the returning electrolyte passing through said tube, and pumping mechanism in said conduit for conveying the electrolyte through said tube to overcome the frictional resistance created by its said narrow bore and enhanced length.

2. An electrolyzer battery for gas separation by water decomposition consisting of a plurality of cells having the combination of means for externally circulating its electrolyte including an electrolyte distributor common to all of said cells, a tube for each of said cells joining it with said distributor consisting of electrical insulation material having an extremely narrow bore with proportionately enhanced length for producing sufficiently high electrical resistance to prevent formation of the shunt currents that are responsible for causing gas impurities in the returning electrolyte passing through said tube, and pumping mechanism in said means for conveying the electrolyte through said tubes to overcome the frictional resistances created by their said narrow bores and enhanced lengths.

WILHELM BOLLER.

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