An Improved Galvanic Element with Constant Current, Applicable Especially for Producing Incandescent Light.
Year: 1890

page_text: Date of Application, 3rd May, 1890-Accepted, 7th June, 1890
COMPLETE SPECIFICATION.
An Improved Galvanic Element with Constant Current, Applicable
Especially for Producing Incandescent Light.
I, JOHN VON DER POPPENBURG of 27 Brandenburg Strasse, Berlin, in the Kingdom
of Prussin, German Empire, manufacturer, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
All galvanic elements hitherto known, more particularly those in which the current
is derived from the decomposition of salts and the formation of oxides, are insufficient
for producing electric light, owing to their rapid decrease in tension and to the high
cost of the requisite material. Constancy of current and cheapness of the material
for producing it are very essential for lighting purposes. In the said clements, the
stability of the current is particularly prejudiced by the decay of the electrode,
without regeneration while the element is inoperative, and by the consequent
deposition of the oxidized metal therefrom on the carbon, whereby the production of
the electric current is discontinued while a sufficient quantity of current producing
material is still at disposal.
The said inconveniences are intended to be obviated by a mechanical means for
preventing the premature decay of the plate of zinc, iron or other metal and by .an
electro-chemically operating means serving to cause the element to be regenerated
while disengaged.
The said mechanical means for obviating the corrosion of the zinc plate during the
formation of oxide of zinc consists in introducing and pressing a suitable porous
filling material, which may be of granular or other consistency, between the two
electrodes of the element. This material is thoroughly pressed into the receptacle
containing the element so as to surround the zinc plate on all sides and cause the
oxide of zinc produced by the electric current to be retained near the surface of the
plate. Consequently, when the disengaged element is being re-formed a complete
regeneration takes place, as the whole of the oxide, owing to its vicinity to the zinc
plate, is allowed to re-unite therewith in the shape of projecting points or bodies of
zinc. As the porous material above referred to, preferably finely cut chaff is
employed but also hay, horse dung, flax or other fibre will be found suitable
material for accomplishing the purpose in question.
To effect the regeneration of zinc while the element is inoperative, I propose
to employ aromatic waters such as are obtained in the manufacture of odorous
oils, for instance rose oil, but also decoctions of wood, branches, straw, flax and
similar vegetable matter constitute a liquid sufficiently aromatic for producing the
desired effect, the degree of which naturally depends on the capacity of the
respective solution.
The vegetable ethers held in solution by the aromatic liquid tend to favor the
regeneration of the element when at rest. This fact, although the nature of the
respective process does not lend itself at present to theoretical explanation, can be
empirically demonstrated by examining the zinc plate shortly after the element
has been in use for some time, and also after it has been allowed to be at rest
for a certain period, subsequent on such use. The difference observable is very
salient. In the first instance, the element shows distinctly the particles of oxide of
zine separated from the zinc plate and detained in the case of chaff by the chips
thereof, while in the second instance, zinc powder and flocks are noticed as adhering
firmly to the zinc plate, together with single chips of chaff which they enclose.
The chips penetrate, so to speak, into the zinc plate.
The improved element may be filled with corresponding
saltpetre, sal-ammoniac, bitter salt, mixed with the boiled chaff.
salts, for instance
But the decoction

page_text: alone, as also constituting an aromatic water through the vegetable ethers in
solution, suffices to produce a constant current.
The mounting of the improved olement is effected as follows:-
Finely cut straw, hay, flax or offal therefrom, or other vegetable hodies, are boiled
in water for the purpose of dissolving the vegetable ethers. The boiled substance
when still moist is brought, with or without admixture of salt or salts as stated above,
into an ordinary element vessel of wood or other convenient material enclosing a
zine plate or two zine plates, and a carhon plate. (Also other electrodes may he
employed). The moist chait, or other substance, is firmly pressed or stamped into
the said vessel. Subsequently a quantity of aromatic water is poured in (which may
also contain corresponding salts in solution) sufficient to completely saturate the
chaff or other filling material and be on the same level therewith.
For producing an element of greater capacity, first a thin zine or other plate is
temporarily placed in the middle between the zinc plate and the carbon plate
introduced into the element vessel. Subsequently the half containing the zine
electrode is filled, up to about 5 centimetres from the rim of the vessel, with smull
pieces of sulphate of copper or other oxide of metal, while the other half con-
taining the carbon plate is stuffed with boiled chaff, which retains, being in a moist
state, the vegetable ethers and is mixed with pulverized sal-ammoniae or other salts.
After taking out the intermediate plate referred to, cold water, saturated with bitter
salt is poured over the whole so as to moisten the sulphate of copper. By this mode
of mounting the element, a very uniform operation of the whole electrodes is attained
until the zine plate is entirely decomposed, which process however is extremely slow.
If the chaff or equivalent material is mixed with corresponding salts, the enrrent
is indeed wenker, as the current-producing material in this arrangement lasts for
years, before it has to be replaced. It is to be observed, that the filling liquid
operates through its vegetable ethers owing to the hydrogen produced during the
generation of the current forming ammonia by the action of these ethers, while the
latter, when the element is inoperative, effect the regeneration of the element.
Having now particularly described and ascertained the nature of my said Invon-
tion and in what manner the same is to be performed, I declare that what I
claim is:
In galvanic elements, the application of porous filling material, moro particularly
cut vegetable matters containing vegetable ethers, for instanco chaff, hay, wood,
leaves, flax, rushes, horse dung, as an interinediate layer between the electrodes, in
combination with a liquid, containing vegetable ethers in aqueous solution, for the
purpose of obviating through the filling material the mechanic decay of the electrode
and effecting by means of the vegetable ethers a regeneration of tho elemont when
inoperative, substantially as set forth.