US936039A - Electrolytic apparatus. - Google Patents

Description

I. L. ROBERTS.

ELBGTROLYTIG APPARATUS.

APPLICATION FILED APE. 3, 1905.

Patented Oct. 5, 1909.

o o O. o o o o o o o o o o o o o o o o o o o o o o o DJ o o o o o o o o o o o o o o. o. o o o o o o o o o o o o o o o o o o .o o o,o o o o o o o o o o o o o o o o o o o cel-l.

rairnerr herren,

ISAIH l.- EGBERTS, OF NEW' YGRII, N. Y.

ELEC'ROLYTIC AEPARATU.

Sp'eceaton of Letters Patent.

Patented Urt. 5, i909.

Application led April 3, 1905. Serial No. 25,384.

Yori: invented certain new and useful l covements in Electrolytic Apparatus.y of 1 1 wlnc ne foliowmgis specication, relerv had to the drawings accompanyrzning a part of the seine.

inve tion relates to porons dias :for e. in batteries and electro'- cells.' Hereofore such diaphragme been of various substances and f s, as for example, of clay molde-d and then baked at a .high temperature; of cements and various other mineral, vegetable and animal substances molded and halted; also of anthracite coal and other carbonaceous materials, the particles of same being hell between suitable mechanical supports, or cemented together. All theseA devices are more or less affected by the acids or alhalies with which they come in contact, while the anthracite diaphragme possess the disadvantage of requiring the use of cement or mechanical supports to hold them in forni. Efforts have been made to use a porous diaphragm or eonducring carbon, but without success, for the reason that, being conducting, the diaphragm will on closing the electrical circuit through it assume a polarity of its own, side beconfiinggjr positive and the other negative, thus setting up a double action in the battery or electrolytio l have therefore been led to devise my present invention, which has for its object the production of a porous diaphragm which is light and strong and which will be'aiiected to a minimum degree, it' at all, by the liquid or liquids in which it is used; and. also the provision of-a simple and elhcient apparatus in which such a diaphragm be employed;

. ln carryingq out the first part of my invention l 'take a sheet or vessel of wood, wood pulp.7 paper, strawboard, or similar material, of the proper size fior the. purpose desired, and char or partially mirbonize the same, suiiiciently to change the organic niaterials therein into acoiuilition in which they willV notV attached by the electrolyte, at

.the Same time without' rendering the `diaphragm suiiciently. conducting to up double electrolytic action. F or example, in making' a diaphragm in the forni or` a cup, l' may taire a bloclrof wood and turn from it a cup or vessel of the desired form and size, allowing of course for the usual slirinl age 1n the process of carbonization. The cup is then placed in a suitable oven and heated very slowly, keeping` the temperature 'as nearly as possible uniform throughout all parts of the vessel. The heating should be` carried only to such a degree that the diaphragm will be charred wit-hout becoming conducting to an appreciable extent.. lt' `the vessel is made from wood of goed quality, that is, of eren grain, free from cracks, etc., it will retain its for i very closely. Instead of making the vessel from wood, by turning the saine from a solid bloclz, it may be formed by molding wood-pulp, or similar material, in a plastic state, or may be built up from sheets of them in any suitable manner. Such a vessel is the-n carbonized in the manner as just described.

lf the diaphragm to be in the form of a fiat plate or sheet, it should be prevented from warping or twisting in the process of carbonization, and for this purpose I use a pair of pl'ates of iron or other suitable material, between which the sheet is clamped during the baking, apertures being provided in the clamping plates to permit escape of the gases of decomposition. The extent to which the diaphragnis are to be heated with- `out rendering them conducting varies, of

course, with the materials used. Within certain limits, however, it is immaterial at what point t-he carbonization is stopped, since it may be carried considerably beyond the point where the material becomes suiiciently resistant to the attack oi acids or alkalies used or developed in the electrolyte or battery solution, Without the diaphragm becoming sufficiently conducting to render it useless for, the purpose intended. It is impossible, on account of the wide ditl'crences in the substances from which the dia phra gms may be made, to give deinite temperatures, or degrees of carbonization, to which they may or shouldv be subjected, but these facts may be readily ascertained for anyparticular kind of material by preliminary trial. iii/'here the electrolyte is i watery that is, a liquid at ordinary temperatures, in contradistinction to a fused bath, the heat used to carbonize the diaphragm should be no higher than is necessary to decompose the organic matter to such a degree that itwill not be attacked by thel gases produced in the electrolysis or by the substances in the solution.

For example, 'chlorin gas will `soon decompose such organic materials as wood, paperboard, strawboard, wood-pulp, etc., but if these are partially carbonized, as described,

' the ysubstancesv wliicli. would unite `.with

chlorin are decomposed or'driven o' in the baking, leaving the diaphragm in proper form and of sutlci'ent strength `to be used for the purpose intended.

For molten baths a cup diaphragm will generally be found more suitable, since 1t does not require the use ofsealed Joints 1n contact with the fusedelectrolyte; whereas Hat diaphragms usic-.d toy divide a tank into compartments requires the joint which its edges make with walls of the' tank to be scaled, as for `exa1nple,jby ,means of asphaltum, paraffin', or similar material. The substances just mentioned melt at comparatively low temperatures, and hence `:ould not withstand the heat of fused electrolytes, which usually are kept at higher temperatures than the melting point of asphaltum, parailin, etc. On the other hand, a hollow diaphragm, as a cup or other yessel, may be plunged to the desired depth into the molten electrolyte wh-ile the seal at the top of the cup, in cases where a seal is desirable, remains out of contact with the bath and may be kept at a much lower temperature.

Referring now to the drawings for a more complete explanation of my invention: Figure l is a perspective view, showing a vessel or lcup ready for carbonization. Fig. 2 is a plan view, showing a convenient clamping device for use in making flat plates or sheets. Fig. 3 is a side elevation of the clamping apparatus.

Referring now to Fig. l, A indicates a vessel in the form of a cylindrical cup, made of turned wood, or molded or otherwise shaped, from any of the materials already mentioned, or their equivalents. It will of course be understood that the cylindrical form of the vessel shown is not an essential feature of the invention, since the diaphragm may be of any desired shape. scribed, the vessel is now partially carbonized, making it porous and unattackable by the substances in the electrolyte'or battery solution, or by the gases evolved therefrom, but leaving` it substantially non-conducting.

In Figs. 2 and 3 I have shown convenient clamping device for retaining a flat plate in shape during its process of carbonization.

The apparatus shown consists of two plates of cast-iron, or other suitable material, indicated by B, 0. These are fastened toy getherat one sidey 1n a convenient manner,

as for example by means of a knuckle joint I), which will permit sheets of different thicknesses to be firmly clamped. At the edges -of the, plates are suitable clamping devices, such as bolts E, pivoted to ears out# standingfrom the plates, 'and carrying at izing of` the diaphragm. After the daphragrn-sheet has been locked in the clamp, I

it is placed in the oven and baked, being careful,as before, to raise the temperature very slowly and evenly so that the diaphragm will not be cracked by too rapid heating. As the carbonization progresses the diaphragmwill shrink and become loose in the clamp, but if the heating is gradual and regular no splitting or cracking of the diaphragm will occur. The cooling should.v also be gradual, so as to produce no sudden lstrain thereon. When the process is completed, it will se found that the sheet of Wood, pulp, strawboard,.or other material, as the case may be, is transformed into a plate of the necessary porosity, and resembling charcoal in its appearance and consistency. The porosity of the diaphragm, in whateverv form the same is made, depends, of course, upon the material used, a diaphragm of charred vstraw-board, pulp-board, etc., being more porous than one from a board or vessel of wood.

From the foregoing it will be seen that my invention provides diaphragms which are light, cheap', and strong, and withal sub.- stantially unaffected by the electrolytic acids or alkalies, etc. It will of course be understood that the method of making the diaphragms may be practiced in a variety of ways, so long as it involves the partial carbonization of a woody article to render itv unattackable by the substances used or evolved in the electrolyte, without making the diaphragm conducting. By the term woody I mean not only wood itself, but also wood-pulp; likewise strawboard, papier mache, paper, and similar organic materials which when partially carbonized retain theirA form to a substantial degree without the necessity of using a binder What I claim is:

l. The method of making porous diaphragins, which consists in forming of woody material 'an article of the desired shape, and'then partially carboniz'ing the vsame throughout to a non-conducting point,

phragms, which'consists in forming an article of'wood, and then partially carbonizin the same throughout to a Anon-conducti.'ig

pbint, asset forth.

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