US2088928A - Electrolytic condenser - Google Patents

Description

3, 1987. s. RUBEN 8 2,088,928

ELECTROLYTI C CONDENSER Filed nv. 4, 1955 I I \NVENTOR Jamaal ifuhm BY I ATTORNEY Patented Aug. 3, 1937 UNITED STATES EL CTROLYTI CONDENSER amuel Ruben, New Rochelle, "N. Y. Application November}, 1935, Serial No. 48,140

a "8 Claims.

ers and particularly to electrolytic condensers of dry ornon-aqueous type.

An object of the invention is to provide an electrolytic condenser having an improved electrolyte.

Another object is the provision of an electrolyte which is viscous, has a high boiling point, a high specific resistance, is hygroscopic, non-corrosive, non-crystalline, which has an organic acid radicle and 'which is adapted to the production oi dry electrolytic condensers by impregnation of the electrolyte into the spacer.

Still another object is the construction of an electrolytic condenser having low leakage and a relatively small amount of deformation when notin use.

A further object is the provision of an electrolytic condenser employing an electrolyte which allows operation on alt ating current with a low power factor over a wide operating temperature range.

Other objects will be apparent from the disclosure and'the drawing in which:

.Fig. 1 is a perspective view, partly broken away,

of one embodiment of the invention showing a ticular ionogen used and is probably due to the flat plate'condenser; t

Fig. 2 is a perspective view ofa modification showing the arrangement .of the invention in coiled form, and

Fig. 3 is a vertical section of an arrangement somewhat similar to Fig. 2, enclosed within a protective casing.

This invention may be said to be a continuation in part of. myco-pending application hearing Serial Number 680,688, filed July 17, 1933.

The present electrolyte differs markedly from the electrolytes of the prior art in its ability to maintain low power factors withspecific resistances many times higher than those of the earlier type of materials, such as borates. This is apparently' a characteristic associated with the parfact that the entire electrolyte is the ionization medium, that is to say, there are no inactive or partially active carriers, suspension mediums or fillers.

My invention comprises the use 01 a lactate of ammonium, potassium or sodium as an improved electrolyte material.

In the dry electrolytic condensers of the prior. art, the electrolytes have been essentially compounds and mixtures of a non-aqueous suspension material such as the polyhydric alcohols-'- glycols and glycerols. The electrolytes produced (Cl. 175-315) This invention relates to electrolytic condens-.

were partly compounds of the salts for instance those salts produced by the combination of boric acid or alkaline base borates with the alcohols, and the conduction was determined by the resulting boiling point aseregulated by the residual water content'inthe electrolyte. As the sparking potential varies with this residual aqueous content, control was naturally established by the boiling point. At some temperatures, these prior electrolytes comprise mixtures of the salt reaction products with the carrier, for example, glycol borates salts dissolved in glycol, so that variations in operating conditions due to changes in operating temperatures were, in part, dependent upon the ratio of compound in solution to the suspension material.

These conditions do not exist in the present electrolyte which is of the non-crystalline type and which is boiled to a temperature higher than that used in the prior art.

I have found that by employing ammonium lactate as t lQelectrolyte, I can produce an electrolytic condenser having a much higher specific resistance than is useable with the borate type and still have a low power factor. For example, it appears that in the construction of an ammonium lactate condenser capable of operation on alternating current, without increase in power factor, when operating at temperatures such as 50 to 60 C., it is very desirable that the electrolyte have a specific resistance in the order of 100,000 ohms per cm. at 20 C. Even with this high resistance, the electrolyte does not require the addition of conductive fillers; This re-- sistance value is obtained by boiling the materials to a temperature in the neighborhood of 195 C.

I prefer to make the electrolyte by the following method: 7.5 c. c. of 28% ammonium hydroxide is added slowly to 10 grams of lactic acid and the solution slowly 'mixed, to form ammonium lactate.

An excess of ammonia can be used as it will be lost on heating. The compound is then boiled to a temperature of 195 C. where it forms a brown viscous and somewhat hygroscopic compound. .The boiled electrolyte is more acidic than the original product, thus indicating the presence of a small amount of lactic acid.

While I preferaam onium' lactate, I have also used both sodium and potassium lactate boiled'to temperatures such as 150 C. to give adequate resistance values necessary for the proper contactv resistance to the formed electrodes. In the 'i'ormation of an electrolyte employing the sodium hydroxide, I have found that the proportion of densers.

solution oi sodium hydroxide is desirable.

The electrolyte can be readily impregnated into spacers commonly used in dry electrolytic con- I have round, that a porous grade of paper 4 mils thick is especially suitable in condensers employing the "electrolyte of this inelectrolyte are particularly useful as motor starting capacitors operating on 110 volts, the high specific resistance of the electrolyte which reduces the efi'ects of impurities and of leakage variations in plate areas being beneficial for alternating current operation. The electrolyte is also adaptable for use in direct current condensers."

The condenser structure used is similar to that now used in the art and is illustrated in the attached drawing in which like numbers indicate like parts.

In the fiat type condenser of Fig. 1, the two film formed aluminum electrodes l and 2 are spaced by the ammonium lactate impregnated spacer I.

In Fig. 2 is shown the condenser of Fig. 1 with the addition of another spacer, 3A, similar to I, which is necessary in order to prevent shorting of the electrodes.

In Fig. 3, the condenser section is housed in metal can I, having an insulator top 5, through which pass terminals Band 1 attached to the respective condenser toils. Insulation at the bottom of the can is provided by pitch 8.

Since certain changes in carrying out the construction of the condenser audits components and obvious substitutions can' be madedn the materials used without departing from the scope oithe invention, it is intended that all. matters contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Having described my invention, what I claim 3 8, 1000 grams of lactic acid to 790 c. c; of a 31% c as new and desire to secure by Letters Patent,

electrodes and a contacting conductive medium between the electrodes composed of a lactate of one of the materials ammonium, sodium or potassium.

2. An electrolytic condenser comprising two electrodes and an electrolyte 01' ammonium lactate.

3. An electrolytic condenser comprising two electrodes at least one of which is film-forming and a contacting conductive medium between the electrodes composed of ammonium lactate.

4. An electrolytic condenser comprising two electrodes at, least one of which is film formed and a cellulose spacing medium therebetween penneated substantially entirely with ammonium lactate, said permeated cellulose contacting the electrodes.

5. A conductive spacer for electrolytic condensers comprising a flexible cellulose sheet material permeated substantially entirely with ammonium lactate so as to ailord a conductive path therethrough.

6.- An electrolyte for electrolytic condensers composed of a lactate of one of the materials ammonium, postassium and sodium and containing a small amount of lactic acid.

7. An electrolytic condenser of the dry type comprising a container and a condenser section therein composed of a pair of electrode foils, at least one of which is filmed, a sheet spacer therebeween and a electrolyte held by said spacer composed of ammonium lactate.

BI An alternating current capacitor comprising a container and a capacitor section therein composed of a pair of med aluminum electrodes, a sheet spacer therebetween and an electrolyte held by said spacer composed of ammonium lactate.

SAMUEL RUBEN.

1. An electrolytic condenser comprising two

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