Improvements in Dry Galvanic Batteries.
Year: 1892

page_text: Date of Application, 4th Aug., 1892-Accepted, 1st Oct., 1892
COMPLETE SPECIFICATION.
Improvements in Dry Galvanic Batteries.
We, CARL CHRISTIAN LESENBERG, of Rostock in the Province of Mecklenburg,
German Empire, Consul, and JOHN VON DER POPPENBURG of 27 Brandenburg
Strasse, Berlin, S., Germany, Manufacturer do hereby declare the nature of our
invention and in what mauner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
Our invention relates to improvements in dry batteries, and consists in employing
a novel filling material of great cheapness, as hereinafter described, whereby the
constancy of the current yielded is preserved for a long time.
The galvanic batteries as constructed hitherto, (and especially those in which
the current is produced by the decomposition of salts and the formation of oxides,)
are subject to a rapid decline of the electromotive force; and in addition to this
inconvenience the materials employed for the production of the current which need
renewal from time to time, are too dear to permit of a general application in
practice. Now the constancy of the current, and the cheapness of its production
are two points of primary importance in galvanic batteries. In the electric
batteries as constructed hitherto the constancy of the current was impaired
principally by the gradual decomposition of the cathode, which was not compensated
by a recombination when the battery was in a state of repose. Furthermore, the
oxidized metal of the cathode was precipitated on the anode (generally of carbon),
and gradually stopped the production of the current, notwithstanding that the
materials were still able by themselves to yield a galvanic current.
We avoid the above defects by filling our improved battery with finely chopped
or ground fibrous materials, such as straw, chaff, and other vegetable matters;
these substances are steeped in warm or hot water, and may then be used for filling
the cells.
Another characteristic feature of our invention is, that the chopped straw or
other vegetable matter may be mixed with hydrates of carbon, such as dextrine,
glucose or starch, and we add such a quantity of water that the entire mass is moist
in itself, yet will not give off any water or moisture.
A further characteristic of our invention consists in partly filling the carbon
cylinder with a hydroxide of chrome prepared in a particular manner. This is a
very important feature of our invention. This hydroxide of chrome is prepared in
the following manner: we take common bichromate of potash, dissolve it in hot water
and precipitate hydroxide of chrome by means of sulphuric acid. Hereafter the
deposit is separated from the liquid above the same, and again dissolved in water.
The carbon cylinder is steeped in this solution, so that it is soaked thoroughly with
hydroxide of chrome, and we also place a small quantity of the precipitate into the
hollow of the carbon cylinder, which is finally closed by means of a cork.
Our invention will be more fully understood by reference to the accompanying
drawings, in which :
Fig. 1 is a central sectional elevation of our improved dry battery.
Fig. 2 is a similar view of a modification thereof.
Figs. 3 & 4 are plane views corresponding to Figs. 1 & 2 respectively.
Similar letters denote similar parts throughout the several views.
In Fig. 1a is a zinc vessel or cup which contains the exciting substance n, i.e. the
chopped straw prepared in the beforesaid manner (the addition of matter containing
dextrine or starch is however not absolutely necessary). In the centre of the said
zinc cup a we place the cylindrical hollow carbon electrode b, which is made
tapering at its upper end, as shown. The opening at the bottom of the carbon
cylinder bis closed up by a cork k, but previously we insert a small quantity of the

page_text: before described hydroxide of chrome as shown at m. When all parts are inserted
in their right position, the cell is closed at the top by means of a cork or similar
substance made impervious by a coating of pitch, as shown at p.
The filling
material constituted by the moist chopped straw or other vegetable matter is
humid enough to effect the production of a current, but will not give off any
moisture. Our improved dry battery yields a very constant current and remains
active for a very long time, especially if it is given a period of repose from time to
time.
In Figs. 2 & 4 we have shown a modification in which the position of the metal and
carbon electrodes has been reversed. In all other respects the construction of the
cell is the same as before described, and will be readily understood by the aid of
the letters of reference marked on the drawing.
We do not confine ourselves to any particular construction of the battery, and
our invention consists in the employment of the new filling material, and in the
novel preparation and use of hydroxide of chrome.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
:-
1. A galvanic dry battery for the production of a constant current, in which the
filling material is constituted by finely chopped or ground vegetable fibrous.material,
and especially chopped straw, said material being soaked in warm or hot water and
filled into the battery in a moist state sufficient for the production of a current, but
not so moist as to cause liquid to exude, for the purpose as described.
2. The addition of a hydrate of carbon, such as starch, glucose, dextrine, or
matters containing these substances, to the vegetable fibrous material constituting
the filling material of the herein before described dry battery, substantially as set
forth.
3. The preparation of hydroxide of chrome by treating a solution of bichromate
of potash with sulphuric acid, and dissolving the precipitated hydroxide of chrome
in water, substantially as and for the purpose described.
4. Soaking the carbon electrode of galvanic batteries in hydroxide of chrome
prepared in the manner set forth in Claim 3.
Dated this 4th day of August 1892.