US2430374A - Electrolytic alkali halogen cell - Google Patents

Description

Nov. l4, 1947. K. E. STUART 2,430,374 ELEC'HOLY'IIC ALKALI HALOGEN CELL Filed Aug. 25, 1945 2 Sheets-Sheet l INVENTOR Nov. 4, 41947. K.\ E. STUART l y ELECTROLYTIC ALKALI HALOGEN CELL Filed Aug, 25, 1945 2 Sheets-Sheet 2 Patented Nov. 4, 1947 ELECTROLYTIC HALO GEN CELL 4 Kenneth E. stuaiumagnra; FaiisN; Y., assigner `to Hooker` yEle otrochemical Company, Niagara Falls, Nail., acorporation of New Yorkj FAppl-icatioxrAligllst^23, 1945,' 'Serial'No:612,1 6-1Y My invention relates more particularly toan` improvement upon the cell disclosed in Patent No. 1,866,065, granted to me July 5, 1932. O-ne object of my invention is to provide a non-conducting member separating and forming liquid tight joints with the outer metal retaining Wall structure of the cathode assembly and the at metal plate to whichthe anodic electrodes are conductively affixed, when this plate constitutes a closure member of the cell. Another object of my invention is to protect this plate against electrolysisv which would otherwise result from aocdental minor leaks past said joints, when the plate constitutes the bottom closure member of the cell.

Referring to the drawings:

Fig. 1 is a sectional elevation through a cell of the type disclosed in the patent referred to, showing the construction of the cathode assembly and bottom closure member, and of the non-conducting separating member.

Fig. 2 is a sectional detail of a portion of cathodic outer metal retaining wall, the bottom olosure member and the non-conducting member, to an enlarged scale.

Fig. 3 is a plan view of the non-conducting member by itself, to a reduced scale.

Fig. 4 is a side elevation of the non-conducting member by itself, partly in section, to the scale of Fig. 3.

Fig. 5 is an end elevation of the non-conducting member by itself, partly in section, to the same scale.

Fig, 6 is a sectional detail of a portion of the oathodic outer metal retaining wall, bottom clo- Sure member and non-conducting member separating the 'tv/0,. all of Ymodified. constructionyto the scale of Fig. 2. L

' Fig'. 7 is a plan'viewof a corner of the nonconductingmember constructed in accordance with the detail of Fig.l 6, but to the scale of Figs. 3 to 5. v l

Fig. 8is a'sectional detail of the bottomgclosure member and non-conducting member` illustrated in Fig. 6, but adapted to aV modied type of cathodic outer metal retaining wall, f

VReferring to Figs. 1 to 5:

Element l is a gas collecting cover member of halogen-resistant, non-conducting material, such as concrete, provided with exit 25 for the halogen gas. Element 2 is the cathode assembly, comprising outer retaining wall 3, provided with exit 26 for hydrogen and Aeiiluent pipe 21 for caustic alkali solution, foraminous cathodc electrodes, #adapted tobe covered with asbestos diaphragm forms the bottom member of the cell, the 4lower endsui electrodes 5 being preferably embedded irisl'abs of lead "I, flgbondedto plate 6. Plate 6 fened by ribs `29, which in turn rest upon *MS-39.5" 1 11] -f.. y .n

Brine `is* supplied Ttothe inner compartment of the "cell, "to serveI ag electrolyte therein, by means bffa'tubular'lcontrolling device, not shown, in ac meeneemt-'nui js.-Paten1;No. 2,183,299, .gratifiedto"Mme December' l?, Element `28 is /afltrolytelevelindicating device, ofthe type `in which'tle pressure built up by Ygas; in this*.oaselchlineftrapped-in a chamber having an opfendofvnw'ardly directed mouth, is indicated by'fa manometer, Ythusgiving a measure of the sbmergence of themouth.

,Dirct""lectrie current is fsupplied to the cell ronafsurce notsho-Wn, through bus bars 25, 25. L Re'sting'fupon plate 16 and conforming with the xterior"shape` of` thecell, is a flat irameAS, of non-conducting material, such as slate, concrete, ,affcjoril'position,,of` asbestos Yber and cement, or otherequivalentmateriah but inthe drawings .sllwnasponstructed of wood. Frame 8 supports Qatliode assemblyzfand constitutes the non-conducting member referred to above. ',Wall is .outwardly ilanged'at 9 and lil, as will be .seen in Figs. ,l vand 2, and the joint between iiange ,LB and frameB is rendered liquid tight by? `,flexible `gasket l l, of foircular cross section, whiclfirlshall refer to as `a rope-type gasket, Iinaceor dan'ce".with Patent No. 2,208,778, granted teme July23 1949. .Gasket Il` isL housed in a groove l2 formed in the upper-surface of` frame 8, butpresents .a rounded surface to flange- Il), whichsurface ,becomes flattenedby pressure ,of tnedlange, ,as illustrated in` the gures. This type .of gasket requires `that the frame oe `Well fllleted at its, corners, as shown in Fig. 3. In the construction of Figs. .Land 2,in which the iriange f Wall -3 is. outwardly ydirected, frame in may ex tend-to the outer edgeof the `ilange, in which case frame Bis preferably formed of four side pieces and four cornerbleplgs i3, as clearly indicated in f3, the.-sidefpieees and corner blocks beingfsecuredQtogether by straps `ifi bolts-.15. The joint betweenlframe 3 and plate 6 is rendered liquid tightby gasket i6., which is similar to gasket il. and; similariymoused n in4 groove` Il, formed in the 4lower,surfage ojfranie' 8. lFrame is, how- 3 ever, secured to plate Ei by bolts I8, and adapted to remain in position when cover I and cathode assembly 2 are removed.

Lead slabs 1, in which the lower ends of anodic electrodes 5 are embedded, are formed by pouring molten lead into the pans `formed by plate 6 and ns I9. The space between electrodes 5, lead slabs '1, fins I9, plate 6, gasket I6 and frame 8 is sealed by pouring in molten bitumen, forming layer 28, which extends between electrodes 5 and completely covers and protects the metallic surfaces associated with the anode assembly.`

Layer 20 is preferably carried upward around its edges so as to cover the upper inner edge of frame 8 and over the upper surface of frame 8 as far as gasket I I. Frame 8 may have been previously rendered water-resistant by impregnation with a water repellent oil, such as linseed oil or a hydrocarbon drying oil; but in any case it is desirable to protect frame 8 as far as possible by carrying layer 2lover it to gasket II`. The material of layer 20 is plastic, even when cold, and will not prevent flange I from seating itself rmly upon gasket I I.

In Fig. 6 there is illustrated a modified structure in which the flanges 2| of cathodic retaining wall 3 are inwardly directed. In this case the anges may be integral with the wall as before, but in the figure are shown as separate pieces welded thereto. One object of this construction is to economize floor space occupied by the cell. A comparison of Figs. 2 and 6 will show at a glance that by the construction of Fig. 6 there is a considerable reduction in the outer dimensions of the cell. This is accomplished, however, at the expense of the lateral space available for the sides of the frame, which is indicated at 22, and which in Fig. 6 constitutes the non-conducting member. Owing to the reduced width of frame 22 as compared with frame 8, the corners may be formed by sawing, steaming and bending, as illustrated in Fig. 7. In this case, since there is no space outside gasket I8 for the holding down bolts, a lag screw 23 is used, and this is placed inside of gasket I6.

In Fig. 6 there is also illustrated another feature of considerable importance, namely drip rim 24, formed along the outer face of frame 22 and extending downwardly around, outside of and below the edge of plate 6, as clearly illustrated in the figure. The purpose of drip rim 24 is as follows: In an alkali halogen cell, the metal parts of the cathode assembly, if of iron, are unaffected by electrolysis. However, plate 6, and all metal parts associated with it, are anodic. There is no known metal but platinum which will withstand nascent halogens. If iron be exposed to anodic conditions in an electrolytic chlorine cell, the chlorine combines with it as fast as withdrawn from the electrolyte. No chlorine whatsoever is liberated upon the iron surface, but all the chlorine appears as ferric chloride. Since this is Very soluble,A under these conditions the iron itself melts away almost as if it were itself soluble. Any accidental minor leak past gaskets II or I6 will therefore have a serious destructive effect upon the edge of plate 6, and in a very short time. Leakage past gasket I6 need never occur if bolts 23 are properly drawn down, and if it should start, can be quickly stopped. Leakage past gasket I I is, however, not always so easily prevented. Nevertheless, by the construction of Fig. 6, electrolyte leaking past gasket I I ows over the outer surface of frame 22 and runs 01T from drip rim 24, without any possibility of its contacting the edge of plate 6. This plate is therefore completely protected against the destructive effect of electroylsis.

In the modification illustrated in Fig. 8, the

cathodic outer retaining wall 3| is flangeless, as

more fully described and illustrated in co-pending application Serial No. 597,259, led June 2, 1945. The upper and lower rims 34 and 35 of wall 3| constitute flat gasket bearing surfaces.

1o The lower rim 34 of wall 3| rests upon gasket 32,

which in this case is a fiat sheet of resilient material covering the upper bearing surface of frame 22. Similarly, the weight of top member I is supported by the upper rim 35 of wall 3|, with flat sheet gasket 33 between.

This application is a continuation-impart of application Serial No. 438,725, led April 13, 1942, now abandoned.

I claim as my invention:

l. In an electrolytic alkali chlorine cell comprising a cathode assembly including a foraminous structure and cathode electrodes housed in an upright liquid-retaining wall provided with a normally horizontal fiat gasket bearing surface 25 all around its lower edge, and an anode assembly co-operative with said cathode assembly including upright anodic electrodes having their lower ends embedded in a slab of low melting metal; the improved support for said cathode and anode assemblies and bottom closure for said retaining wall comprising a at metal plate extending beneath said retaining wall completely across from side to side thereof and conductively affixed to said slab; a flat, four-sided open frame of impervious electrically non-conducting material intervening between said plate and the cathode assembly conforming with said gasket bearing surface in plan View, and having upper and lower boundary surfaces lying in planes paralleling said gasket bearing surface; a gasket of resilient material between said gasket bearing surface and said frame supporting the weight of the cathode assembly; a drip rim around the lower outer edge of said frame outside and extending downwardly of said plate, protecting said plate against anodic electrolysis in case of leakage of electrolyte past said gasket; a second gasket between said frame and said plate and tension means compressing said second gasket between said frame and said plate; said slab and plate being protected against anodic electrolysis by a layer of impervious electrically non-conducting pressure-plastic material extending around and between the lower ends of said anodic electrodes to said frame and making a sealing bond therewith.

2. In an electrolytic alkali chlorine cell comprising a cathode assembly including a foraminous structure and cathodic electrodes housed in an upright liquid-retaining wall provided with a normally horizontal flat gasket bearing surface all around its lower edge and an anode assembly cooperative with said cathode assembly including upright anodic electrodes having their lower ends embedded in a slab of low melting metal;

the improved support for said cathode and anode assemblies and bottom closure for said retaining wall comprising a fiat metal plate extending beneath said retaining wall completely across from side to side thereof and conductively aflixed to said slab; a flat, four-sided open frame of impervious, electrically nonconducting material intervening between said plate and the cathode assembly, conforming with said gasket bearing surface in plan View, and having upper and lower boundary surfaces lying in planes paralleling said gasket bearing surface; a gasket of resilient material between said gasket bearing surface and said frame supporting the weight of the cathode assembly, said plate being mortised into the bottom of said frame, leaving said frame extending 5 outwardly and downwardly of said plate to form a drip rim protecting said plate against anodic electrolysis in case of leakage of electrolyte past said gasket; a second gasket between said frame and said plate; and tension means compressing 10 said second gasket between the frame Vand the plate; said slab and plate being protected against anodic electrolysis by a layer of impervious electrically non-conducting pressure-plastic material extending around and between the lower ends of said anodc electrode to said frame and making a sealing bond therewith.

KENNETH E. STUART.

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

UNITED STATES PATENTS

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