US2093574A - Venting device for electrolytic condensers - Google Patents

Description

p 2 1937- J. POITRAS 2,093,574

,YsuTmGpEvIcE FOR ELECTROLYTIC CONDENSERS Filed larch 26, 1934 zzmuu IIlllllll I.

u I I l l l I i I I l IINVENTOR JOSEPH .P TR/9S ATTORNEY r'atented Sept. 21, 1937 PATENT OFFICE 'VENTING DEVICE FOR ELEC'IBOLYTIO CONDENSEBS Joseph A. Poitras, Fort Lee, N. J., assignor to Solar Manufacturing Corporation, a corporation of New York Application March 26, 1934, Serial No. 717,348

4 Claim.

This invention relates to improvements in electrolytic devices, such as electrolytic condensers, rectifiers or the like, comprising film-forming electrodes.

5 In such devices, use is made of the film-forming eii'ect exhibited by certain metals, like aluminum, tantalum or magnesium, which when placed in suitable electrolytes, upon application of the proper voltage, are covered with a film. Such l films consist of partially hydrated aluminum or tantalum oxide and have a unidirectional conductivity for the electrical current.

'Ihese condensers are used for different purposes, one of their principal uses being in filter 15 circuits to eliminate the alternating current ripples from rectified currents. However, it should be well understood that my invention is not at all limited to such purposes and applications, but, as will become apparent, has a much wider scope 20 which will reach beyond that of electrolytic condcnsers in general.

In electrolytic condensers, such as are used for the above stated purpose, only one of the electrodes, namely the anodefis required to be of 25 film-forming metal,preferredly aluminum.

The cathode which, as a rule, also forms the container of the condenser, is either made of a metal which does not exhibit film formation, like copper or nickel, or even of aluminumalso, which, where 30 it comes into direct contact with the electrolyte, can be plated with chromium or the like. Such containers which simultaneously form the cathode, can be shaped in difl'erent ways,-as a rule they consist. substantially of a tubular mantle 35 which at one end is crimped over a dished lid, or the rim of the latter is beaded over the edge of the former, as shown in the present illustration, while the other end forms a hermetically sealed seam around an insulating bushing, supporting the anode member. In my copending application, Serial No. 71mm filed July 24, 193,4, 1 have shown the total construction of such a condenser, still as the present invention does not lay 45 any claims to any parts of such construction, .but

rather to asingle feature serving a special function, yet to be explained, all such details are omitted in the accompanying drawing, and the fiagode member itself is only indicated by its oute. It is also immaterial for. the present inventive concept how the inner electrode or anode is formed, whether in the form of single spaced plates or a single plate, rolled into a spiral, or 55 finally as is shown in my co-pendlng application mentioned above.

In either case the inner space between the anode and the cathode container is filled by the electrolyte solution, preferredly up to above the top rim of the anode plate, to prevent sparking over as well as corrosion in consequence of the sparking over, or any corona effect. This electrolyte filler may either be in a liquid or a semiliquid condition, and for aluminum electrodes a variety of acid or sodium electrolytic solutions are in use, as for example, sodium sulphate, potassium permanganate, ammonium chromate, cyanide of potassium, sodium silicate (semi-liquid) ammonium phosphate or citrate and finally, as the most commonly used: borax. Tantalum condensers use mostly an acid electrolyte, like sulphuric acid, or ammonium chloride, borate or sulphate or mixtures of sulphuric acid with other salts. In all cases, however, there occurs, as a result of the electrolytic action, a continuous more or less copious formation of gas bubbles,

mostly of oxygen (in the case of cyanide of potassium of nitrogen), as not all the oxygen is used in the formation of the film or forms water with the nascent hydrogen. For this accumulating gas pressure an outlet must be provided, especial- 1y as in addition the electrolytic action is accompanied by a development of heat, and to provide such an outlet in a novel and improved form, is the general purpose of the present invention.

I am aware that various schemes have been devised and triedin practiceto deaerize" electrolytic cells and thereby prevent eventual explosions", with spilling of acid and other accidents, but these safety devices, though effective when p of-N3 131:!v constructed and handled, do not take a sufficient care of the human element and are as me not foolproof. Consequently they will occasionally fail, besides having other drawbacks. Sometimes, where the lid consists of insulating material of considerable thickness, the gas vent consists of a hole drilled through the lid which for shipment or before installation is plugged with wax to prevent spilling of the electrolyte. when the condenser is put into service the wax plug is supposed to be removed or punctured to permit escape of the gases. Or a thin sheet of rubber is-cemented over the vent hole which also should be punctured before service commences. In another construction the vent hole device comprises a conical rubber nipple, the tip of which is to be perforated by a needle hole which ordinarily oses up but opens when the gas pressure is sumciently great, or the rubber nipple has a weakened portion which is supposed to rupture r I under the force of gas pressure. These latter two devices oftenfail under abnormal operating conditions; i. e. when a great volume of gas is suddenly developed. Moreover all these devices depend upon human precaution. While it is necessary that they should be kept hermetically closed during shipment and handling, it is presuming too muchthat all buyers of such devices, among Whom there are necessarily many amateurs who install their own radio hookups, will not neglect to provide proper perforations before connecting the condensers. Such an oversight is liable to happen even to those skilled in the art.

Even so, if the perforations are in time provided, 7

there remains the danger, especially in portable sets, that, should the assembled apparatus be brought into a lateral or overturned position, the electrolyte may seep out of the now permanently open vent hole, which in addition may have been made too large. This is another drawback which is successfully prevented in applicant's improved I "venting device.

It is therefore among the objects of the present invention to provide a degassing or venting device for gas containers which from the start works automatically.

A further object of my invention is to provide an automatic degassing or venting device for electrolytic condensers which from the start is in a 80 working condition.

Another corollary object is to provide such an automatic venting device which while always being in an efilcient working condition, is hermeti cally closed during shipment or handling.

85 Another object of my invention is to provide a venting device which automatically opens without rupture of any rubber diaphragm whenever sumcient gas pressure is applied to it and automatically and hermetically closes again.

A further object is to provide a venting device of the kind described which, when open, provides an ample exit for a sudden excess gas pressure.

A further object of my invention is to provide a venting device for electrolytic condensers which .45 can be shipped ready for installation and immediate service.

A further object of my invention is to provide a venting device for electrolytic condensers which does not require any manual preparation, previous to active and automatic service and is therefore ,foolproof.

Other more specific objects and advantages of my device will appear as the nature of the improvements is better understood, the invention consisting substantially in the novel arrangement and correlation of instrumentalities herein fully described and illustrated in the accompanying drawing wherein similar reference characters are used to describe corresponding parts throughout 0 the several views and then finally pointed out and specifically definedand indicated in the appended claims.

The disclosure made the basis of exemplifying the present inventive concept suggests a practical 5 embodiment thereof, but the invention is not to be restricted to the exact details of this disclosure, and the latter therefore is to be understood from an illustrative, rather than a restrictive standpoint. In the accompanying drawing- Fig 1 is a top view of a condenser, in which one form of my invention is embodied;

Fig. 2 is a cross-section along line 2-2 of Fig. 1; Fig. 3 is a detail view in perspective, partly I broken, showing the valve cap and the gasket over scribed.

the gas escapes in cross section, with the clamp for the resilient member partly turned to better disclose its shape;

Fig. 4 is a top view of a modified form;

Fig. 5 is a cross-section along line 55 of Fig. 4;

Fig. 6 is a detail view in perspective, showing the star-shaped spring which gives resiliency to the valve lid;

Fig. 7 shows a third modification, embodying the principles of my invention, partly in crosssection;

Fig. 8 illustrates the valve body, shown in full in the previous figure, in cross-section.

Referring more in detail to the different views, III indicates the cylindrical mantle of the container of the condenser in the different modifications, and I I designates the dished lid, inserted into one end of this mantle. In most cases this is the top end, the terminal connections being provided at the bottom end, as shown more fully in my copending application, although such an arrangement is not indispensable and might as well be reversed, if so desired. The container, including the dished lid, is usually made of aluminum, as aforesaid, and the anode element I2 which is only outlined, is, of course, of film-forming material, aluminum or tantalum.

The dished lid II has an annular flange Ila which is slightly tapered toward the inside and the upper edge IIb is crimped over the extreme end of the tubular mantle Ill, which is spun inwardly to secure a tight fit with the lid. The electrolyte which fills the space between the container and the inner electrode and also any empty spaces within the portions of the latter, is indicated by I3. 3

The middle portion of the dished member II (see Figs. 1 and 2) is raised to form a cylindrical head I I which has a bigger central opening I5 and several smaller perforations I 6, concentrically located around the latter, through which gas can 40 escape. Over these gas holes is provided a pliable 1; gasket I'|, made of soft rubber or leather or an equivalent material, and this loose gasket is kept in place by a mushroom-shaped lid I8, clamped over said gasket by a resilient member, anchored on the underside of the cylindrical head I 4. The resilient member comprises a saddle-like anchor -I 9, made of a metal strip, bent in inverted U form, and a resilient cushion 20, which may consist either of a very soft rubber ring supported on the projecting ends of the anchor I9, or even of alight coil spring (not especially illustrated) applied in the same way. The depressed central portion of the lid I8 is coupled to the top of the anchor I9 through opening I5 by a rivet 2|, and it will be clear from the description that ordinarily the gas holes I6 are kept closed by the tension of the resilient member 20, pressing the lid l8 and gasket I1 against them, but that any excess gas pressure will evenly raise the gasket against the resiliency of the anchor, until enough gas has escaped. 1 The modification shownin Figs. 4 and 5 differs from the first device principally by the shape of the anchor I9u. and the absence of a special resilient cushion. The anchor itself is a resilient washer, having the shape of a three-pointed star, as shown separately in Fig. 6. The device functions in a similar way as the one previously. de-

The third modification, illustrated in Figs. 7 and 8, shows the whole venting device countersunk in the top lid 22 and consisting principally of non-metallic valve parts.

The dished lid 22 has a middle portion in the 15 form of a depressed funnel-shaped cup 22a. The conical portion of the funnel can either be smooth or be provided with an annular offset to better seat the valve body, and the vent holes 23 are provided in this conical portion. At the end, protruding toward, the interior of the container, the

funnel ends in a short cylindrical nozzle 22b.

In this cylindrical nozzle and partly on the conical slope is seated the valve body P, represent 2lb. The other part 25 consists of a rather flat saucer-shaped disk which fits into the part 2! by means of a male and female connection. A short cylindrical plug 250, integral with the disk, fits into a close fitting recess 140 in the inner end of the cylindrical neck 24a. Opposite the male connection part 25c is a recess 25d for countersinking the slotted buttonhead of the tap screw 2.6 which passes through a central perforation in the member 25 and is threaded tightly into the member 24, as plainly shown in Fig. 8. A little metal washer (which advantageously may. be a resilient split washer, to prevent spontaneous loosening of the screw) may be inserted underneath the head of the screw. The saucer-shaped flange 25a, when the screw 26 is tightened, should press tightly against the vent holes 23, and to insure a tight fit, the slope of the flange 25a should be somewhat less than that of the funnel portion 2211., so that by tightening the screw the slight clearance over the neck portion 24a, between the flange 25a and the funnel 22a is eliminated.

It is evident that any excessive gas pressure reaching the saucer-shaped flange 25a through the vent holes 23, temporarily lifts up the flange which, as so as the pressure is released, will hermetically lose the holes again. It is equally evident that normally, when there is no gas pressure, the resilient part 25a or in the formerly described constructions, the gaskets I'I effectively seal the vent holes, no matter in what position the condensers are held or are being shipped; also that, to install the latter, no perforations or unscrewing oi. shipping caps or'the like, are necessary.

In accordance with the provisions of the patent statutes, I have described my invention, but I desire it understood that it is not confined to the particular form shown and described, the same being merely illustrative, and that the invention may be carried out in other ways without departing from the spirit of my invention, and therefore I claim broadly the right to employ all equivalent instrumentalities comingwithin the scope of the appended claims, and by means of which, objects of my invention are attained and new results accompllshed, as it is obvious that the particular embodiments herein shown and described are only some of many that may be employed to attain these objects and accomplish these results.

Having thus described my invention, what I "claim and desire to secure by Letters Patent, is:

1. A self-closing relief valve, adapted to release gas from an electrolytic condenser, provided with a multiplicity of concentrically arranged vent holes in its container wall, said valve comprising an annular gasket, seated over said vent holes, a cover enclosing said annular gasket, and resilient means to normally press said cover against said gasket, closing the vent holes hermetically.

2. A self-closing relief valve, adapted to release gas from an electrolytic condenser, provided witha multiplicity of concentrically arranged vent holes in its container wall, said valve comprising an annular gasket, seated over said vent holes, a dished cap inverted over said annular gasket, and a resilient anchor positioned in the center oi said cap and adapted to yieldingly anchor the dished cap with the gasket to the container wall.

3. A self -closing automatic relief valve, adapted to relieve the surplus gas pressure in an electrolytic condenser, provided with avent in a cupped portion of its container wall, said valve comprising a pliable gasket adapted to yieldingly close said vent, a cover clamped over said gasket and a spring member positioned on the opposite inner side of the container, coupled to the cover through an aperture in the container and adapted to anchor the cover and gasket resiliently to the container-wall.

4. A self-closing automatic relief valve, adapted to relieve the surplus gas pressure in an electrolytic condenser, provided with a multiplicity of vent holes in circular arrangement through its container wall, said valve comprising a pliableannular member adapted to cover the vent holes from the outside, a resilient member seated on solid unperforated parts of the container wall on the inside, and clamping means to couple the outside annular member to'the inside resilient member in such a way that the gas pressure can lift the outside member away from the vent holes against the resiliency of the inside member.

JOSEPH A. POI'I'RAS.

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