US2199447A - Electrolytic condenser - Google Patents

Description

May 7, 1940- s. RUBEN ELECTROLYTIC CONDENSER Filed sept. so, "51937 INVENTOR Bfamufjuflz ATTORNEY .Patented Mey 7, 1940 UNITED STATES PATENT ori-Ica 2,199,441' e amcfraounc coNDaNsEa samuel aubea'New Boehme. N. Y. l Application september so, 1931, serai No. 166,548

claim. (ci. 11s- 315) This invention relates to dry electrolytic con-.- densers, and more particularly to spacer elements employed therein.

`An object of the invention is the provision of 5 an improved composite spacer element comprising'.` two or more sheet materials cemented together. s

A further object is the provision of an adhesive material for cementing two or more condenser spacers into one sheet.

Another object is the provision of an adhesive. especially suitable for eementing non-brous and ilbrous sheet spacers so as to allow their use in composite form in -the'manufacture of dry electrolytic condensers.

vFurther objects will be apparent from the disclosure and from the drawing in which Fig. 1 shows a spacer element; Fig.. 2 illustrates a cross section of the spacer shown in Fig. 1; Fig. 2o 3 shows a spacer element wound in coil form between two electrodes to form a condenser unit, and Fig. 4 shows a condenser in coil form mounted within a container.

In my United States Letters Patent 1,918,716, I describe a dry electrolytic 'condenser employing a plasticized and electrically conductive regenerated cellulose spacer such as cellophane. The spacers referred to in this application are for use in condensers of the type described in that patent. f

The use of a cellophane spacer in dry electrolytic condensers permits the application of potentials beyond that possible with paper or gauze type spacers. 'I'he non-pervious, ,-non-ilbrous character of the cellulose forces a uniform distribution of current over the entire contacting electrode and prevents localization of current in any one area when high' potentials are applied or where higher operating temperatures are encountered or utilized. These advantages are somewhat reduced because the contact between the aluminum electrodes and Cellopha-ne" is not quite as satisfactory as with fibrous materials and because cellophane is more dimcult to impreg- 45 nate than paper or gauze. y To improve the contact and facilitate impregnation a combination of Q "cellophane and paper, or cellophane and gauze has been used. However, the use of such combinations involves additional machinery and 50 added cost of manufacture due to the extra care which is required in winding the added rolls with the two rolls of ioil and two rolls of spacer.

I have found that by cementing the spacers; for instance one layer of cellophane and one u layer oi' paper, or one layer of cellophane and one layer of gauze, or one layer of "cellophane" sandwiched between two papers, `a composite spacer is obtained whichA can be `'employed in place of single lspacers without the addition of extra rolls and which may'be woundinto con- 5 densers by the methods now generally employed. Although a large number of materials can be used to cement the cellophane and paper, -o1" hard and soft paper, the important requirement in an adhesive for this purpose is to provide the l0 Aproper chemical and electrical properties. The -f cementing agent must be misclble and compatible with the types of electrolytes used in dry electrolytic condensers, for example, ammonium glycol borate electrolytes, and must not contain ions l5 that will tend to reduce the sparking potential of the anode illm or bring about corrosion of the electrodes. Such an adhesive must also assist or allow the cellophane" or paper to become as conductive as possible so as to permit a low power factor.

In order to meet these requirements I have developed a cementing agent comprising a water soluble gum, such as gum arabic, and an aqueous mixture of tri-ethylene glycol. The preferred v proportions which allow practical handling without excessive distortion of the cellophane and provide necessary electrical conditions, are 50 grams of powdered gum arabic, U. S. P., dissolved in 200 c. c. of distilled water containing 20 c. c. of ,30 tri-ethylene glycol, maintained at 90 C. until a clear homogeneous mixture is obtained. 'These proportions may, of course, be changed depending upon the consistency desired, degree of heat which will be applied to the cemented materials, etc. In the preparation of a spacer comprising a sheet of cellophane between two sheets of paper, the Ce1lophane" is passed through the adhesive solution and rolled up in contact with the papers, and thereafter through a drying oven. o The composite spacer is then ready'for winding with the condenser foil armatures. In the case of a nat type condenser, only one spacer is required, but in the case of the conventional roll type condenser, two of the composite spacers are required. After the condenser has been rolled it can be impregnated with electrolyte. the porous character of the paper insuring the presence of an adequate quantity of electrolyte over the oper` ating life of the condenser.

The particular example given above describes the use of the adhesive in a spacer comprising a sheet of cellophane between two sheets of paper, but the adhesive may also be used in the following laminated spacer constructions: two u sheets oi.' hard or soft paper; one sheet of hard paper and one sheet oi' soft paper; one sheet of hardpaper between two sheets of soft paper; one sheet of cellophane and one sheet o1' paper; one sheet of Cellophane and one sheet of gauze; one sheet of cellophane between two sheets of gauze.

'I'he presence of the tri-ethylene glycol in the adhesive serves to plasticize and keep the Cellophane in a moist condition, at the same time facilitating impregnation of the cellophane and paper by the electrolyte and thereby providing good electrical conductivity from the elec-` trodes through the spacers. While ethylene glycol or glycerine can be substituted for the trlethylene glycol, they are not as satisfactory as they do not insure the permanent moist condition brought labout by the latter, Pure gum tragacanth or chloride free mannitol can be substituted for gum arabic, but the latter is preferred.

In order to afford a detailed description oi' the spacer and of the condenser using the spacer, reference is made to the accompanying drawing in which similar numerals indicate similar parts.

In Fig. 1, the spacer element I consists of nonbrous regenerated cellulose sheet 2, cemented between soft porous paper sheets 3 and l, by the tri-ethylene glycol-gum arabic adhesive described above and shown in exaggerated form at l in Fig. 2.

The coiled condenser construction of Fig. 3 shows spacers l, wound between aluminum electrode foils 6 and 1.

In Fig. 4, rthe condenser unit 8, similar to the condenser shown in Fig. 3, is mounted within aluminum container 3 and insulatedI therefrom by pitch I0. Cathode tab Il, is grounded to the wall or the container which acts as the negative terminal, and anode tab I2, is connected to termina] Il, which extends through "Bakelite top Il, which serves to seal the condenser.

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

1. A spacer pre-assembly for dry electrolytic condensers comprising at least two sheets of dry electrolytic condenser spacer material in faceto-iace relation, and an adhesive comprising triethylene glycol and a water soluble gum cementing said sheets together.

2. A spacer pre-assembly for dry electrolytic condensers comprising at least two sheets of dry 'electrolytic condenser spacer material in faceto-Iace relation, and an adhesive comprising triethylene glycol and gum arabic cementing said sheets together.

3. A spacer pre-assembly for dry electrolytic condensers comprising at least one sheet of nonfibrous cellulose film and at least one sheet oi flbrous cellulosic material in face-to-face relation, and an -adheslve comprising tri-ethylene glycol and a water soluble gum cementing said sheets together.

4. A spacer pre-assembly for dry electrolytic condensers comprising at least one sheet of non- Ilbrous cellulose lm and at least one sheet of fibrous cellulosic material in face-to-face relation, and an adhesive comprising tri-ethylene.

glycol and gum arabic cementing said sheets together.

5. The method of making dry electrolytic condenser assemblies which comprises cementing at least ltwo sheets of condenser spacer material together with a cement comprising a polyhydric alcohol and a water soluble gum and subsequently winding said cemented spacer between two sheet metal electrodes at least one of which is of film-forming metal and then impregnating SAMUEL RUBEN.

the assembly with a nlmmaintaining electrolyte. y

Images