US1789949A - Electrolytic cell - Google Patents

Description

Jan, 20 1931. A. GEoRGIEv ELEGTROLYTIC CELL ashun-sneer 1 Filed Oct. 18, 1930 xNvENToR Alexaadered La ATToRNEYa IIHNHIINIHI Y Humm Jan. 20, 1931.

A. GEORGIEV ELEcTRoLYTIc CELL Filed Oct. 18. 19:50

2 Sheets-Sheet 2 Rwi. O E m@ m wm -M @YM/.M .AB/ n e Pltented Jul. 20, 1931 UNITED STATES yPATENTN oFr-l'cs ALEXANDER GEORGIEV, OF BROOKLYN, NEW Y'OBK, ASSIGNOB T0 AEROVOX WIRELESS CORPORATION, A CORPORATION 0F NEW YORK ELECTBOLYTIC CELL Application led October 18, 1980. SerialkNo. 489,521.

My present invention relates to electrolytic cells, useful as rectifiers and lightning arresters, but is more especially applicable to condensers of the electrolytic type, in which the di-electric is formed in a thin film upon the surface of the anode by electro-chemical action.

It is an object of the invention to provide an essentially dry condenser of the above type, of stablevand dependable character7 affording high capacitance in small bulk, of low electrical leakage, self-healing im character and which may be used without likelihood of breakdown in filter circuits and power supply units of radio receiving sets, in telephony and in other relations. Y

Another object is to provide a simple and practical method for producing and forming condensers of the above type, which shall require no expensive or highly specialized equipment, or close attention or delicate ad- Justrnent or regulation by highly skilled supervisors.

Another object is to avoid the loss in capacitance and the consequent increase in cost and bulk, incurred when the expedient of series-connection of two or more condensers is resorted to, in order to prevent breakdown under high voltages, the condenser by its mode of construction being rendered operative under higher voltages than ordinary electrolytic condensers.

Another object is to provide a condenser of the above type, devoid of liquid apt to slosh around in the casing and yet not subject to excessive heating or excessive evolution of gas pressure during use.

Another object is to provide a condenser of the above type, light in weight and compact in construction, which can be employed with substantially equal effectiveness, upright, inverted, horizontal or at any inclination, accord/ing to the space left available by associated apparatus.

v Another object is to provide an electrolytic condenser of the above type, of a minimum number of elements, or parts, yet with adequate shielding between the individual con# denser sections, enclosed in the same can and superior in performance though devoid of any filling of pitch, paraliin or the like.

Another object is to provide a condenser of the above type, devoid of joints, connections or other surfaces, subject to corrosion by gal-l vanic action or otherwise, which will maintainjts full eflicacy after even long period of use or of idleness or disuse, without high leakage currents when operation is resumed.

A feature ofthe invention is the lateral misalignment, as by stag erin of the longitudinal edges of the anode and cathode folls of the condenser roll. By virtue of this staggering, the edge of the cathode is spaced at a substantial distance from that of the anode, and the concentration of electrostatic field at the anode edge is consequently reduced; the undesirable consequences of imperfect film formation at the anode edge (such'as excessive electrical leakage and sparking over) being, to a great extent,- overcome. -By this4 arrangement, while the capacitance of the condenser is not reduced for practical urposes, as compared with a condenser in w ich the foils are in registry, yet the gap atvthe edges of the roll is so greatly increased that the leakage and the likelihood of break-down at theseregions arel greatly reduced and the condenser may be made to serve satisfactorily and with low power losses, at high peak voltages.

Another feature is the electrostatic shielding of the condenser roll by the simple ex pedient of the outermost convolution of thel outer orcathode foil completely encircling the condenser roll therewithin.

Another feature is the use of the identical metal, preferably aluminum for the cathode,

formed and the ohmic resistance of the condenser increases, the effective application of voltage rises in a direct proportion therewith, thereby insuring the formation of a uniform tough adherent lm on the anode foil.

Another feature is the treatment of all screws or metallic washers and similar parts connected to the anode and entering into the condenser construction, to form a di-electric film thereon, similar to that on the anode foil, thus to preclude areas of high leakage.

Another feature is thearrangement of condenser roll or rolls loosely within an otherwise empty can, to which the cathode terminals are directly connected, the anode being connected to bmding posts through an insulating can cover.

The method of impregnation and forming is not claimed herein but is the subject matter of a divisional application Ser. No. 504,911

lfiled Dec. 16, 1930.

In the accompanying drawings in which is shown one of various possible embodiments of the several features of the invention,

vFig. 1 is a perspective view showing the constituent elements of the condenserCl before winding,

Fig. 2 is a perspective view showing the condenser partly wound,

Fig. 3 isa perspective view showing the condenser completely wound.

Fig. 4 is a plan view indicating themethod of forming,

' Fig. 5 is a,transverse sectional view on the line of lT ig. a, showing the forming arrangement,

Fig. 6 is a top view of cased condenser,

7 is a transverse sectional view talren on the line .7-7 of Fig. 0,

Fig. 8 is a View in transverse cross-section of the condenser on line 8-8 of Fig. 7

Fig. 9 is a fragmentary detail of vent construction, and,

Fig. 10 is a section on a larger scale on line 10-10 of Fig. 9.

Referring now to Fig. 1 of the drawings, the condenser is made preferably of a 'pair of armature foils comprising an anode 10 and a cathode 1l, of suitable film forming metal preferably aluminum, with an absorbent separator, which may comprisean interposed sheet 12, preferably of gauze, paper or the like, of width greater than that of the foils, reversely folded over an end of foil 10 to provide an additional sheet 13 superposed over foil 10. 0f course, two or more superposed sheets of gauze or paper may be used depending on the nature and texture of the interlay, the character of the electrolyte and the complete enthevoltage at which the apparatus is to be used. The absorbent separator should cover the total area of the anode in order to assure c. about the condenser which is .l

The cathode foil 11 is provided wlth a termi- C nal tab tpreferably formed by slitting the foil preferably transversely near one end for nearly the entire width thereof, to provide a tongue 15, which is reverselybent as at 16,

so that the tab t may protrude beyond one.

end of the condenser roll. The anode foil 10 is similarly provided with a similar termif nal tab t2, preferably at the other end, cut from the opposite longitudinal edge to protrude'from the opposite end of the condenser roll.

The superposed layers of foil and fabric are Wound together to provide a flattened roll with the terminal tabs t andz2 of the two foil ends protruding from opposite ends of the roll, the anode foil tab 252 from the axis of the roll, the cathode foil tab t from the surface of the roll. rlhe gauze or other electrolyte retainer should extend the free protruding edge of t? and preferably also of the catho 'lhe outer foil preferably aff length to provide one or two et.

Winding by. an encirclingband 28. turn or turns 1l perform the tiireef tion of a unitary capacitative chanical protector for the roil ig n dling prior to final lassembly' and asu erior conductor to dissipate heat generated in use.

The interlay of the condenser roll is now impregnated with a suitable liquid electrolyte. Thisis accomplished by immersion of the completed dry roll prepared as just set forth, in a tank containing the hot electrolyte. The general advantages of my invention are attained by the use of any of the electrolytes commonly employed for the purpose, for instance glycerol and carbonate of soda, as disclosed in the prior patent to Hiclrley No.4 900,27 8 of October '8, 1908, but the voltage withstood by the condenser and its capacitance willdepend largely upon the choice of electrolyte. 'f

The condenser elements are then subjected to the forming operation, preferably by laying them in trays or pans 21 of glass, aluminum or other material unaffected by the solution, filled preferably with liquid'identical with the batch in the impregnation tank. Preferably the condenser terminals t and t2 are connected to releasable terminal clips 23 and 24 respectively mounted at opposite edges of the -tray and abo-ve the level of the liquid therein. Care is taken that the foil 11 forming the electrostatic shield is connected to the negative terminal'of the current source, to constitute the cathode. In series with the condensers, a few only of which are connected in parallel in each tray 21 is connected a resistor R preferably of about 2000 ohms more or less depending on the voltage, the number of sections and their dimensions. Each resistor is in turn connected in series with a corresponding incandescent lamp L, the remaining terminal of which is connected to the positive terminal of the source of current G, which is preferably of a voltage slightly in excess of the eak voltage for which the condenser is to be adapted. The trays as indicated in Fig. 4, may be conveniently arranged in rows on racks or tables and all connected in parallel across the terminals of said source of forming current G. A closed circuit jack 26 is disposed in each circuit, for ready connection of a milli-ammeter, -for metering leakage current in ascertaining completion of the formlng process.

In the forming operation, the initial resistance of the immersed condenser roll is very low since the current flows only across a thin film of conductive electrolyte of large area interposed between the two condenser electrodes. The initial voltage across the condenser will be very small as practically the entire volta-ge drop will be across resistor R and lamp L. The small voltage on the condenser roll will form a very thin film upon the anode foil 11, the electrical resistance of which rises accordingly. Therefore, a larger proportion of the applied voltage will now be applied across the condenser foils, which brings about the form ation of a greater thickness of film, resulting in the application of still higher voltage to the condenser. In this manner the voltage applied across the condenser foils will gradually and automatically increase in a direct proportion with the formation of the di-electric film, until, upon the completion of the forming operation, the resistance of the condenser will be vastly higher than that of the resistor R and practically all of the voltage will be applied across the condenser terminals. This operaton' 1s continued until the voltage impressed across the condenser foils is slightly in excess of the peak voltage on which the condenser is to be used. Where the peak voltage is 500, the forming voltage is preferably about 510.

With the arrangement above described,

the lamp L serves to give visual indication when -the forming lprocess is about completed. At the beginning of the forming operation, and while it is in progress, the voltage applied to the lamp will be sufficiently high for incandescence thereof, but as the formation proceeds and the resistance of the condenser dominates, thelamp will becomedimmer due to' the resulting reduction in voltage thereacross and finally will beextinguished. The supervisor will thus be apprised of the substantial progress of the forming operation and thereafter, with the aid of the milli-ammeter applied at the closed circuit jack 26, he will know when the forming operation has been completed,' at which time the condenser roll is removed from the tray. `The condenser roll thus formed, willv have a di-electric film uoonl the anode 10 of thickness depending on the voltage and duration of forming o eration, and the intcrlay will be soaked wit the electrolyte liquid in contactwith the film.

The individual formed condenser is preferably enclosed in a can C, preferably of the same metal as the condenser electrodes. Preferably the cathode tab t is at the bottom of the can and the anode t2 at the top, as shown in the drawings. Depending on the choice of capacitances desired in the' completed unit, one, two or more separate condenser rolls in parallel may be used. In the vexample shown in the drawings, three such condenser rolls D', D2 and Ds are shown,

separately and jointly encircled by a single wrapping band W of insulatin fiber or paper, as shown,the upper edge o which, as shown, extends above the condenser rolls. Preferably, no electrolyte, except what remains absorbed in the interlay 12-13 is put in the can, nor is the same sealed with pitch, paraffin or other filling composition.

To complete the assembly, the one, two or more terminal tabs t of the cathode, protruding from the lower ends @f the condenser rolls are riveted, soldered or welded at 29 to a metal strip 30 extending downward within the can C from near the upper end thereof, or the tabs may, if desired, be

-riveted or otherwise connected directly to the can. A terminal lug 3l is riveted as at 43 to the exterior of the can C, said rivets also mechanically holding the upper end of the conductive strip 30, thereby connecting the lower terminals of the condenser rolls to the can, which itself serves as one terminal of the condenser assembly. The other terminals t? of the condenser 'elements are respectively clamped directly as shown, under the heads of screws 33. The screws 33 extend upward Athrough the insulating cover 34 of the can and with corresponding nuts 33', serve as binding posts. The cover is preferably molded with shoulders 35, which lock the square headed binding post screws, and prevent turning thereof, when the corresponding nut 33 is tightened or loosened. The

can is preferably formed with a bead 36 upon which the cover 34 rests and the rim of the can is turned inward as at 37 to permanently affix said cover, an interposed gasket 38 assuring a tight connection. Preferably rubber washers w and wz encircle each binding post screw and are pressed against opposite faces of cover 34, thereby to prevent any lll possible ooze of electrolyte by creepage from the interlay 12--13.

The binding posts 33, rivets 29 and preferably also the rivets 43 and 44, hereinafter described, are joints at which corrosive action might occur in the absence of other precautions. tion, these screw connectors and rivets are made of the saine metal, aluminum, as the electrodes, and the can, and in addition, the binding posts and other aluminum fittings or parts, such as the washers connected to the anode, are subjected to a forming operation, prior to incorporation into the condenser. This forming operation is analogous to that performed on the condenser rolls themselves. vrl'he washers and screws in a perforated can are submerged in electrolyte liquid, preferably identical with that used in the condenser rolls, and there subiected to direct current until a thin tough i'ilm has formed over the surface of elements. The anode tab t2 being an integral p t the anode foil and submerged in the electrolyte is simultaneously wi i the anode.

Preferably, the condenser, after complete assembly thereof, as shown in Figs. 7 and 8, is subjected to further forming operation by connection across lreni-*rater toassure completion of the he condens,

described, is not subject isturbance on, as would be in curred in use on es or other rapidly moving vehicles, 3 sorbed liquid were LJ T I the con x, and ii a non-volaes erred, i ce ir esing or evaporation.

" l nce of liquid, also afantage in installa l Ji or inclined, and thus oe ntteci many relations, where may a wet condenser could not be employed withincreasing the bulk of the apparatus.

By the present invention, the use of paper, oil cloth or other wrapping for the individual condenser rolls, the p fallin or wax dipping and the pitch sealing, all are eliminated, with a resultant product of reduced weight, reduced cost for .labor and materials, and reduced bulk for a given capacitance.

By the elimination of paran, waX or' pitch, there is avoided, on the one hand, any injury to the electrolytic iilm, due to the heat of' suoli composition, when poured in, and, on the other hand, any heat generated in use of the condenser is more readily dissipated due to the absence from the structure of any such poor heat conductors as paper, oil-cloth, wax or pitch. Substantial voids between the condenser roll and can are substantially devoid of filling composition, thereby to facilitate convection currents of air and heat dissipation.

According to the present-inven-- No disturbing coupling eifects occur as between the individual condenser sections rwithin the can, each such section though not otherwise enclosed, being completely shielded electrostatically `by the outermost turn or turns of the cathode foil.

'llhe film being built up or formed upon the pre-wound condenser, it is not subject to such injurious strain as may be incurred where the foil section is formed rst, and the section then wound. The film by my forming method having, moreover, been built up gradually on the pre-wound condenser section, such film is homogeneous, tough and permanent, so that the condenser remains effective even after long periods 'of use or idleness, and requires no reforming operation to i restore it to operativeness.

rlhe formation occurring in a tray with a comparatively large quantity of electrolyte, free circulation thereof occurs and excessive heat especially inthe inner convoutions of 'the section is avoided, and at the same time complete retention of liquid electrolyte in the interstices of the absorbent interlay is assured.

By the staggering of the electrode foils, there is effected a multiplication in the length of path for leakage current of dashover between the sharp edge ofthe anode and'- tl e sharp of the catho-de foils, which edges the greatest electrostatic intensity occurs. Thus both leakage current danger of breakdown are ininimivt Vf here the cathode anode foils are not breakdown the edge of the rely occur because of the prokiini'ty of two sharp edges of high electrostatic inten 'ty, because of the comparative imperfection oi forming at the sharp more or less jagged anode edge, and such breakdown is to be permanent.,

By staggering, the distance between the anode and cathode edges is greatly increased, correspondingly reducing the probability of should such flash-over .nevertheless occur under an abnormal surge of voltage, it would be attenuated and therefore reforming or healing of the afiected'part on the anode edge would take place more readily.

Unlike the case of non-inductively wound wan' impregnated condensers, no marked loss in effective area of the electrolytic condenser results by staggering of the Jfoils, since the dielectric film will form on substantially the entire area of the anode, even o n that protruding beyond the cathode, the electrolyte in the gauze which is the true cathode being in engagement. with the entire area of the dielectric film.

All metal parts being of aluminum and all washers and screws associated with the anode being electrolytically formed, the condenser has long life, as there are no parts, subjectl 130 to corrosion b chemical or lvanic action,

.and no objectionable variations in leakage,

tuberance within the .can formed by the in dentation, and is preferably backed by a heavier metal washer 42, the latter assisting in secure mechanical and electrical contact of the parts, held together by rivets 43 and 44 through the lug 31, the can C, the strip 30 and the'backing washer 42. J The lug, the indentation, the strip and the washer 42 are erforated at p for venting through* the ruber washer 41, which has a pin hole 41 therethrough, shown exaggerated in the drawl ings.

The pin hole 41 is normally closed and excludes dust and dirt and other foreign matter. Under eventual gas pressure within the case, the rubber will expand to open the pinhole and allow venting therethrough by way of perforations p, the vent immediately closing when the pressure has thus been relieved. The Vent thus normally closed, also prevents escape of any electrolyte by creepage from the moist interlay. l p

It will thus be seen that there are herein described, apparatus and methods, in which the several features of this invention are embodied, and which in service attain the various objects of the invention and are well suited to meet the requirements of practical use. f

As many changes could be made in the above disclosure, l'and many apparently widely different vembodiments of this invention could be made without departing from the scope thereof, it i-s intended that all matter contained in the above description or shown in the accompanying drawings lshall be interpreted as illustrative and not in a limiting' sense.

Having thus described my invention, whaty I claim as new and desirel to secure by Letters Patent is 1. An elctrolytic cell'having anvactive cell element comprising cathode and anode foils displaced with respect to each other with substantially the entire length of the anode edge protruding with respect to the corresponding length of the cathode edge, said cell including a thin dielectric :[ilm closely adhering substantially to the entire effective area of the anode foil, means for retaining a layer of electrolyte interposed between the .cathode and anode foils and extending at least to the free protruding edge of the anode foil, a container enclosing the active cell element and presenting substantial voids therein, said protruding foil edge freely exposed to the air within sai container to facilitate cooling and the escape into the voids in the container of gas generated in the cell during o ration.

2. An electric con'denser roll inc uding convolute cathode and anode foils having their longer edges at the ends of the roll displaced with respect to each other longitudinally of the roll with the cathode foil protruding at one end of the roll beyond the anode and the latter similarly protrudl beyond the cathode at the opposite end ldigthe roll, said condenser including a thin film of dielectric closel adherin substantially to the entire effective area o the anode means for retaining a layer of electrolyte interposed between the cathode andanode foils and extending at least to the free rotrudin edge of the anode foil and means or establiiing terminal connection of the res ective foils at the respective protruding e ges thereof.

3. An electrolytic condenser comprising elongated cathode and anode foils of substantially equal width, an interposed sheet of librous material having electrolyte absorbed therein, said foils and sheet being convolute to form a roll, the foils staggered with respect to each other lengthwise of the roll with the anode edge protruding beyond the cathode at one end of the roll and the cathode edge beyond the anode at the opposite end of the roll, said sheet of fibrousmaterial extending at least to the protruding edges of both cathode and anodel foils.

4. An electrolytic condenser comprising a pair of metal foils of substantially the same width including elongated cathode and anode foils, the latter having a dielectric ilm over substantially the entire area thereof, an absorbent separator sheet interposed between said film and said cathode foil and having electrolyte absorbed therein, said foils and Y -each other, said separator sheet extending at least tothe protruding edges of both cathode and anode foils and terminal tabs unitary with the respective foils and extending from the respective protruding edges thereof.

5. An electrolytic condenser having an active condenser element including a pair of elongated metal foils withy an interposed absorbent separator sheet, electrolyte absorbed therein, said foils and sheet being -rolled together, the various edges of said foils being non-aligned with respect to each other, said separator sheet superposed'over the entire area of said metal foils, a container enclosing and determining substantial voids about said active condenser element, said container being substantially devoid of filling composi.

tion or of electrolyte externally of the active terminal'cooperating with said `joint, a cover condenser element, thereby to facilitate conof insulating material for said container, vection currents of air. and a binding post through said cover and `6.1m electrolytic condenser comprising a aflxed to the other terminal of saidconroll having convolute layers of anode foil and denser. y cathode foil, a dielectric film u on the anode 12. An electrolytic condenser comprising foil in contact therewith', the oil at the ex a sheet metal can, an electrolytic condenser terior of the roll having an outer turn comroll therein longitudinally thereof, said roll pletely encircling the roll, the outer end of having one terminal near the lower end of said outer foil protrudin beyond -the end of Said can and the other at the upper art the other foil, and direct y overlying and enthereof, a terminal lug at the exterior o? the gaging the underlying area of said outer foil. can wall, a sheety metal strip riveted to said 7. An electric condenser comprising a roll terminal lug, the lower terminal of said conhavin convolute layers' of anode foil end denser roll aflixed to said sheet metal strip catho e foil, a dielectric film upon the anode an insulating cover for said can, a binding A foil in Contact therewith, the cathode foil post therethrough, the outer terminal of said being at the exterior of the roll and having Condenser roll connected to said binding post, an outer turn completely encircling the roll saidcan being substantially devoid of filling the outer end of said cathode foil protrudcempollnd. ing beyond the end of the anode and directly 13. An electrical condenser comprising an overlying` and engaging the underlying active electrolytic condenser unit inclu ing cathode area. y cathode and anode foils, the latter coated with 8.v An electrolytic condenser roll eempris'. a dielectric film, a separator between said film ing an elongated cathode foil, an elongated` end Seid CethOde and impregnated With anode foil, the long edges of said foils' stagelectrolyte, ametal jacket about the condenser gered-with respect to each other and a brous unit, n can enClOSing the jaeketed unit and interla sheet impregnated with electrolyte, having an insulating cover, the cathode havsaid foil and sheets being rolled to ether with ing; e terminal Strip electrically and mechanthe'cathode foil completely encircling the exically J'Olned t0 the body Of the een fOr electerior of the roll the outer end of seid cathode trical connection thereat, an electrical termifoil protrudingvbeyond the end of the anode nal cooperating with said joint, and a termiand directly overlying and engaging the nal through the cover of the can connected underlying cathode area. to the anode.

9. An electrolytic cell comprising mede 14. An electr1c condenser comprising a and cathode foils extending in substantially @OndeIlSeI 10ll including' en anode an a superposed relationship, with the anode foil' Cathode fOll in SllPeIpOSed relatiOnShip, a

protruding beyond the edge of the cathode thin dielectric film closely adhering to the` foil and coated with 'e thin adhering film 0f anode foil, a fibrous interl'ay between the di-electric, said cell having an l encircling film end the cathode and impregnated with layer of metal about and in electrical and electrolyte, the cathode foil being at the exmechanical contact with the cathode foil and teIiOr and having One Ol InOre Outer cOnvOluconstituting en electro-Statie shield, d tions completely encircling the roll, the outer- 10. An velectrol tic condenser roll includ-#nest parttef the cathode foil prOtrlldng ,being convolute cat ode and anode foils, havyOnOl the nOde and the interlay to directly ing their longer edges at the ends of the roll Overlie endengege the cathode area theredis laced with respect to each other longiunder, a metal can enclosing said roll, the tudmally of the roll, said condenser includ- CethOde being electrically cOnnected to the ing a thin film of di-electric closely adhering een, and the anode being electrically insuto the entire effective area of the anode foil, lated With respect to the can.

means for retaining a layer of electrolyte 15. An electrolytic condenser comprisin interposed bet-Ween the film and the cathode, a sheet metal can, an electrolytic condenser the outer convolution of the cathode foil therein extending longitudinally thereof completely encircling the roll the outer end comprising an anode foil, a cathode foil, an of seid cathode foil protruding beyond the interposed fibrous layer soaked with electroend of the anode and directly overlying and lyte,said super osed'layers in rolled relation, engaging the underlying cathode area wherewith the catho e at the exterior and presentby said outer convolution constitutes an elecing an Outer cOnvOlntiOn encircling the roll, tro-static shield. the outermost 11. An electric condenser comprising a truding beyon the anode and the layer to conductive container, a wound electrolytic dllectly OVeI'lie and engage the Cathode area condenser roll therein and extending longithereunder, Seid IOll hnving One terminal tudinally thereof, a terminal strip protrudv teh et the bOtiOm end the Other et the top 0f (part of the cathode foil .pro.

ing from one end of said roll and mechanithe can, meansy electrically connecting thel cally joined directly to the wall of said conbottom terminal with respect to the can wall, tainer, said container having an electrical an insulating cover for the can and a binding post therethrough and connected t'o the upper condenser terminal.

16. -An electrolytic condenser comprising a sheet metal can, a lurality'of electrolytic condenser rolls therein each including a convolute cathode, anode and fibrous nterlay, the latter having electrol te soaked therein, each of said condensers aving the cathode foil as an outer enclosing layer thereof, insulating sheet material isolating the several condenser rolls with respect to each other, a terminal lug on the condenser can, the cathode terminals of the respective condenser rolls electrically connected to said terminal tab, and an insulating coverfor the can having binding posts therethrou h connected to the respective anode termina s of the condenser rolls.

17. An electro] ic condenser comprising an anode foil, a brous sheet and a cathode foil in superposedrelation, wound in a roll with the anode foil protruding beyond the cathode foil at one end of the roll, the cathode foil having one or more turns at the' exterior completely encircling said roll, the outermost part of the cathode foil protruding beyond the anode and the sheet to directly overlie and, engage the cathode area thereunder, a metal can enclosing said roll, the cathode electrically connected'to the Wall of the can and the anode electrically insulated from the wall of the can. 18. An electrolytic condenser comprising anode and cathode foils of aluminum, fibrous sheet means between said foils and impregnated with electrolyte, a closely adhering film of dielectric on the anode area, a can of aluminum enclosing said condenser roll and presenting air spaces thereabout, an aluminum part unitary with said cathode foil and in direct mechanical contact with the lateral wall of said can for terminal connection thereto, the anode having a terminal insulated from the can, the voids between the condenser roll and the can being substantially devoid of filling composition thereby to facilitate convection currents of air.

19. An electrolytic condenser including an active condenser element having electrodes of identical metal, a dielectric film formed on one of said electrodes, an enclosing metallic can of the same metal as said electrodes, the wall of which determines air spaces about the active condenser element, a terminal for said latter electrode insulated from the can, a terminal for'the other electrode directly afiixed to said can mechanically and electrically, metallic connecting members electrically and mechanically associating said electrodes with their respective terminals, each of said mmetal as said electrodes, the voids between the active condenser element and the can being substantially devoid of filling composition,

thereby-to'facilitate convection currents of air.

20. An electrolytic condenser including an active condenser element having electrodes bers being of the same metal as said electrodes, those of said connecting members that are aflixed to the anode having a film formed thereon of substantially the same composition as the (li-electric film on the anode foil.

21. An electrolytic condenser comprising f an aluminum can, a condenser unit containe v therein comprising electrodes of aluminum, the anode having an electrolytic film adhering to the active surface thereof, a fibrous interlay kbetween the two electrodes impreg nated withl a liquid electrolyte, aluminum connectors mechanically and electrically bonding the cathode to said can, an insulating cover for said can, aluminum binding post screws and associated metal parts of aluminum in electric contact with the anode foil, said aluminum screws and parts having cach a film formed thereon of substantially the same composition as the anode film.

22. In van electrolytic condenser, a can having an indentation, a piece of rubber in said indentation having a pin-hole therethrough, a terminal lug superposed over said rubber and affixed to said condenser, said can and said lug having each al small aperture at opposite faces ofthe rubber piece and substantially aligned with the pin-hole therein.

23. An electrolyticl condenser including an anode foil having an integral terminal tab, acathode foil contiguous to said anode, and an electrolytic film upon said anode, said con-` denser section being enclosed in a metal can, said cathode electrically connected to said can, an anode bindinglpost insulated with respect to said can, means clamping said anode l terminal tab to said binding post, said anode tab, said binding post and associated metal v elements being all of the same metal as said identical with that of said anode. 4

24. An electrolytic cell including cathode and anode foils displaced with respect to each other with substantially the entire length of the anode edge at one end of the cell protruding beyond the corresponding edge of the cathode area, said cell includin a thin electrolytic film closely adhering su stantially to the' entire areaof the anode foil, means for retaining a layer "of electrolyte interposed between the cathode and anode foils and extending at least to the free protruding edge of the anode foil, 'the cathode foil having a portion encircling the anode parts and 1nsulated therefrom and having an end portion no i protruding beyond the anode and directl en- 1. ga 'ng and overlying theV cathode area t e ereun er.

25. An electrolytic condenser including convolute cathode and anode foils having their lon er edges at the ends of the roll displaced with respect to each other longitudinally of the roll, said condenser including a -thin film of dielectric'closely adhering substantially to theentire area of the' anode foil, means for retaining a layer of electrolyte inter osedbetween the cathode and anode foils, an extending atleast to the free protruding edge ofthe anode foil, the cathode foil being at the exterior and having one or more outer convolutions completely encircling' the roll, f

the outermost end of the cathode foil protruding beyond the anode to directly overlie and engage the cathode area thereunder.

26. Anelectrolytic condenser including an active condenser element having cathode and anode elements of identical metal displaced withl respect to each other with the entire length of the anode edge protruding beyond the cathode at one end of the condenser, said cell including a ,thin electrolytic -flm closely adhering substantiallyv to the entire area of the anode foil, means for retainin a layer of electrolyte interposed between t e cathode and anode foils, and extending at least to the free protruding edge ofthe anode vfoil, the cathode presenting one or more convolutions at the exterior of the cell insulated with respect to the anode and presenting a free protruding end portion in direct engagement with the underlying cathode portion, an en- DISCLAIMER 1,789,949. Alexander Georgien, Brooklyn, N. Y. ELEcTRonYTIc CELL. Patent dated January 20, 1931. Disclalmer filed February 27, 1936, bythe assignee, A670002: Corporation.

Hereby enters its disclaimer to claims 6 and 7 of said patent.` [Oficial Gazette March 17, 1.936.]

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