Feed device for electrolytic cells

March 23, 1954

C. C. S1LSBY, JR

2,673,232

FEED DEVICE FOR ELECTROLYTIC CELLS

Filed Jan. 24, 1950

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INVENTOR.

CHRISTOPHER C. SILSBY, JR.

BY

Patented Mar. 23, 1954

2,673,232

UNITED STATES PATENT OFFICE

2,673,232

FEED DEVICE FOR ELECTROLYTIC CELLS

Christopher C. Silsby, Jr., Euclid, Ohio, assignor to Diamond Alkali Company, Cleveland Ohio a corporation of Delaware

Application January 24, 1950, Serial No. 140,327 (Cl. 174—15)

Claims.

This invention relates feed device for delivering :___________„ — to an electrolytic cell, and more particularly relates to a means for disintegrating said stream into discrete droplets to prevent unwanted flow of electricity from a cell and for regulating the rate of delivery of the electrolyte stream to the cell.

It is of paramount importance in commercial electrolysis plants for the electrolysis of aqueous solutions of electrolytes that the electrolytic cells be isolated electrically from the source of the feed stream of electrolyte solution fed thereto m order that there be no dissipation of electric current to the stream outside the cell. Likewise, it is of importance that there be no means by which arcing of the electric current may take place between electrical conductors within the cell, since such arcing may touch off a chemical reaction of the evolved gases, i. e., hydrogen and chlorine or hydrogen and oxygen, which reaction may then proceed with explosive violence. An explosion may be touched off by arcing of the electric current between droplets of the electrolyte solution where the droplets of the feed solution are projected directly into the body of electrolyte within the cell.

Stream-breaking means heretofore proposed for disintegrating a feed stream of electrolyte solution have included devices in which the stream is projected at high pressure from an onfice longitudinally against the inside surface of a tubular member opening into a cell, whereby the stream impinging upon the inside surface of the tube spreads around the inner periphery thereof and is said to leave the end of the tub” °^{f a conical Bheet} which ultimately disintegrates into a mass of discrete particles A ^^Ornrifi?^P1® ^{fOr the same} P^urP°^se includes an orifice inserted in the feed line, the orifice ί,ΗτΌποΉ o «λ π — · , &gt; ally into the cell ^a sufficient to permit the stream to disintegrate by disrupting intermolecular cohesive forces of the solution during its fall

In addition to the dangers of the phenomenon of arcing between droplets noted hereinabove with such prior art stream disintegrating feed devices, the range of solution feed rates which tbre ^ρΓθξθ^{ηί electrica}l grounding of the cell through the feed stream is relatively narrow in the spray-type disintegrator because low feed rates preclude the feed stream moving with suffiH®,^PV^Pf^{ed to maintain th}c formation of a thin of^thi^hepf⁸’^ *5? ^subsequent disintegration ^th - ^{sh lnt0} discrete droplets, and in the to a stream-breaking a solution of electrolyte single orifice type because high feed rates preclude allowance for sufficient practicable vertical distances through which the stream must fall before its disintegration is effected.

An object of the invention is to provide a metering feed device for feeding electrolyte to an electrolytic cell which shall insulate the feed supply from the cell at all times.

Another object of the present invention is to provide an electrolyte solution stream disintegrator for electrolytic cells, which disintegrator may be operated over a relatively wide range of feed rates within which the disintegration of the feed stream, and consequently the isolation of uhe cell electrically, is assured.

Another object of the invention is to provide an electrolyte solution disintegrator for an electrolytic cell feed device, the capacity of which may be varied as the capacity of the cell changes from time to time.

_Q My7^{ther objeet of the} invention is to provide a feed device for feeding a solution of electrolyte to an electrolytic cell, which device precludes explosions within the cell due to arcing of an electric current between droplets of the electrolyte solution fed thereto.

These and other objects of the invention will e apparent from the detailed description of the invention set forth hereinafter.

nJt^hehi^r!7^{ing attaohed} h^eto and forming a ^{ereof 13 a} vertical sectional elevation, through an apparatus representing one form of the invention.

In the drawing, 2 is a take-off from a manifnirt ^^OlUiiOn header line, in which a metering orifice 4 is inserted and is supported by tube 6 entering chamber or reservoir 8 formed by supKXre ^mbr/^{2 a}?^{d St0PPer} ‘°’· ^a pfi of ber 12 ^1Π t^® ^{floor of su}PP°^rting memvoir i^ ^\^{the sides and floor of r}eseryp ’^Ms ‘⁶ discharge from chamber 8 into an “^{terior 01} eage 30, which is fabricated from an electrical insulating material, preferably a transparent material, such as glass or transpart pherl as S^1O38?^aStlCS’^ ^{iS Ventsd to the at}“⁰®Γη whirh ³⁸ ’ « ^{30 1S su}PP°rted by base 24, in which stopper 26 and line 28, emptying cage M are taeerted; _tes. _a, 1„ “g stopper 26, line 28, and the lower portion of °^age, ³θ’ *^{orins a} hquid-tight catch basin for droplets 20; base 24 and jet support 12 may be of electrical insulating material, similar to that 2;„f^{age and are heId in rigid} assembly by be 65 ta?/ ^{and bottom rin}S^s 34 secured by ke buck-stays 32, which may also, if desired be of

2,67 electrical insulating material, which are held in place by nuts 36. The object, of course, is to isolate the top and bottom zones of the apparatus electrically by whatever arrangement of non-conducting parts may be feasible in a given application of the invention.

In operating the feed device of the present invention, a solution of electrolyte is fed from takeoff tube 2 through metering orifice 4 under suitable hydrostatic head of pressure into chamber 8; the rate of flow of the electrolyte solution into this chamber, and consequently the rate at which the solution is fed to the cell, is governed by the size of the opening in orifice 4 and the hydrostatic pressure upon the solution above the orifice; the stream of electrolyte solution is discharged from chamber 8 through jets 16 initially as a solid stream 18, which ultimately disintegrates into droplets 20, which are collected at the base of cage 30 as a continuous body of solution, which then flows to the cell through line 28.

Opening 38, shown above the normal liquid level of cage 30 but suitably below the lower limit of unbroken electrolyte stream from jets 16, serves a two-fold purpose, in that it is open to the atmosphere and therefore permits the stream issuing from orifice 4 and jets 16 to be discharged against a substantially constant head of pressure, whereby the flow of brine or the like through the apparatus may readily be maintained at any desired constant rate, and in that the opening 38 serves as an overflow in the event of blocking along line 28 from cage 30 to a cell suitably to prevent the flow of current through the disintegrator. If cage 30 is not vented to the atmosphere, pressure variations within the cage, due to the hydrostatic head of pressure above orifice 4 and the pressure within the electrolytic cell exerted through line 28, may cause erratic operation of the metering orifice, for example, by in- 40 creasing the pressure within the cage and thereby diminishing the flow to an amount substantially less than the capacity of the cell to electrolyze the solution, and thereby allow the level of electrolyte in the cell to fall below the top of the elec- ₄₅trodes, which in turn permits intermixing of cathodic and anodic gases, for example, hydrogen and chlorine or hydrogen and oxygen, and increases the danger of explosion within the cell.

The rate of flow of electrolyte solution through ₅₀orifice 4 at any given time is necessarily determined by and is proportional to the working capacity of the cell, i. e., the amperage, at that time, and is controlled directly by the hydrostatic head of liquid in line 2 above orifice 4. The effective- ₅₅ness of the apparatus to disintegrate the feed stream is not impaired as the flow of liquid through the jets 16 approaches zero, and therefore flow rates less than that required to satisfy the maximum capacity of the cell need not be taken into account in designing the apparatus. This follows from the fact that at a given solution flow rate, for example, a flow rate equal to the maximum capacity of the cell to which it is fed, the streams issuing from the jets will disintegrate within a determinable distance proportional to the size of the openings in the jets and the speed with which the issuing stream moves. Any lesser rate of flow will cause these streams to disintegrate within a lesser distance. The length of cage 30 and the size of the openings in jets 16, as well as the number of jets, may thus be integrated to the maximum working capacity of a cell to electrolyze the solution and to the requisite rate of flow of solution through orifice 4 to satisfy

3,232 that capacity. In determining the size of the orifice 4 and the number and sizes of jets 16 to be used in the stream disintegrating mechanism, it is important first to determine the available hy6 drostatic head above orifice 4 and to co-ordinate the size of the opening in the orifice with the hydrostatic head, so as to obtain a flow somewhat greater than the maximum capacity of the cell to electrolyze the solution fed thereto. Thereafter, 10 the number and size of the openings of the jets 16 to be employed are suitably adjusted to the maximum allowable length of cage 30 in order that the streams of liquid issuing from the jets disintegrate into discrete droplets before reaching the 15 body of solution at the base of cage 30.

In gauging the size of the openings in jets 16, the diameter of the orifice 4 is suitably less than the sum of the diameters of the openings in the total of jets 16, whereby the disintegration of the 20 streams issuing from the jets is effected within a distance less than that required theoretically to disintegrate a stream issuing from orifice 4; suitably orifice 4 is within the range 0.1 to 0.8 the sum of the diameters of the total of jets 16, but pre25 ferred value of operations lies in the range from

0.6 to 0.8. In ordinary commercial practice, a suitable allowable length for cage 30 has been found to be of the order of 12 to 20 inches.

Data relative to these features of the invention 30 are tabulated below to show the relationship of the size of the openings in the jets to the flow rates obtainable therethrough and the distance through which the stream issuing from the jets must fall in order to effect the disintegration 35 thereof into discrete particles.

TABLE

Using 3 lets

Diameter, Inches

Flow Rate, cc./min.

Distance of Stream Fall to Disinter grate, Inches

0.125.

0.157.

0.157.

0.187.

0.250.

1,100

200

3,000

2,100

3,200

19.5

In designing cage 30 for a cell having a maximum capacity within the range of flow rates given in the table above, it is preferred practice to have the length of the cage at least 3-4 inches more than the corresponding distance of stream fall to disintegrate. This assures sufficient free fall of the droplets to prevent electrolysis of the feed stream, either because of arcing of the current between the droplets or because of a continuous stream of electrolyte solution reaching the pool at the bottom of the cage. However, any arcing 60 which may occur within cage 30 is ineffective in initiating an explosion since intermixing of anodic and cathodic gases cannot occur in this region in the apparatus and therefore, a much safer operation of an electrolytic cell is assured.

While there has been illustrated and described in detail an embodiment of the invention, the described structure is not intended to be understood as limiting the scope of the invention as it is realized that changes therewithin are possible 70 and it is further intended that each element or instrumentality recited in any of the following claims is to be understood as referring to all equivalent elements or instrumentalities for accomplishing substantially the same results in 75 substantially the same or equivalent manner, it

2,673,232 5 being intended to cover the invention broadly in whatever form its principle may be utilized.