IMPROVEMENTS IN GALVANIC BATTERIES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Charles Denton Abel at the Office
of the Commissioners of Patents on the 6th November 1883. Communicated
to him from Abroad by Gustav Przibram, Hermann Scholz, and Wilhelm
Wenzel, all of Vienna in the Empire of Austria
CHARLES DENTON ABEL of N° 28 Southampton Buildings, Chancery Lane, in the
County of Middlesex "IMPROVEMENTS IN GALVANIC BATTERIES". [communicated
to him from Abroad by Gustav Przibram, Hermann Scholz, and Wilhelm Wenzel,
all of Vienna in the Empire of Austria]
This invention relates to an improved construction of constant elements for
galvanic batteries. The galvanic element is composed of two electrodes which may
either both be of metal, or one of them may be of a mineral substance, and three
conducting liquids, these parts being disposed in a vessel divided by means of two
diaphragms or partitions into three compartments. The positive electrode, which
is made either of platinum, carbon, or silver, is placed in a compartment of the
element containing pure nitric acid of from 30° to 40° Beaumé. The negativo
electrode is placed in a second compartment of the element, containing a solution
of one part by weight of common salt in about 20 parts by weight of water, or
filled with some alkaline liquid. The third compartment of the element, separated
from the other two by a porous-diaphragm made of clay or other suitable porous
substance, contains concentrated sulphuric acid of from 50° to 70° Beaumé. The
clements may be of any desired shape, such as cylindrical, oval, prismatic or
rectangular and the diaphragms may be disposed one inside the other in the form of
concentric vessels, or one by the side of the other in the form of flat partitions.
According to one construction the outer vessel, which may be of glass or other
suitable material, has two concentric cylindrical partitions which may be formed in
one piece. The central compartment within the inner partition being filled with
nitric acid, contains the positive electrode of platinum or carbon. The annular
compartment between the inner and outer partition is only partially filled with
sulphuric acid in order to leave space for the increase of the volume of the liquid
caused by the energetic penetration into it of nitric acid through the inner
partition and of water through the outer partition. The annular compartment
between the outer partition and the inner wall of the outer vessel contains

page_text: preferably a solution of common salt or some alkaline solution, or a dilute mineral
or vegetable acid; in this is immersed the negative electrode of zinc. The above
arrangement may be variously modified; thus the position of the electrodes and
their liquids may be the reverse of that above described, or the positive electrode
may be in the outer compartment, the negative electrode in the intermediate one,
and the sulphuric acid in the central compartment; or again, the sulphuric acid
may be in the outer compartment, the positive electrode and the nitric acid in the
middle compartment, and the negative electrode in the central compartment.
In any of the enumerated dispositions, the diaphragın separating the nitric acid
from the sulphuric acid ought to be made somewhat lower than the other
diaphragm, or it ought to be provided in its upper portion with holes or with
incisions; the purpose of this arrangement is that, when the level of the sulphuric
acid is rising and the level of the nitric acid is falling, in consequence of the
constant absorption of the nitric acid by the sulphuric acid through the porous
diaphragm, the thus obtained mixture of both acids may overflow towards the
positive electrode. Thus the positivo electrode constantly remains immersed up to
a sufficient height in acid, whereby the constancy of the element and the duration
of its working is considerably increased.
-
When the improved element is so constructed, that the diaphragms are placed
not concentrically, one inside the other, but one beside the other, the prismatical
or rectangular shape may be very advantageously adapted. In this case the
diaphragus or partitions are by preference cemented or otherwise secured by
packing in grooves formed in the opposite walls of the outer vessel. The one
compartment for containing the sulphuric acid is preferably made smaller than the
other two, and is situated in the middle between the other two containing the
positive and negative electrodes; or the position of the compartments may be
modified in a similar manner to that above described, the sulphuric acid being
contained in one or other of the two end compartments.
The diaphragm or partition separating the sulphuric from the nitric acid is also
in this case made somewhat lower than the other, or provided with notches or
holes for the purpose above stated.
IN
The action of the above described improved element is based upon very energetic
chemical and electrolytical processes which take place as follows: from the nitric
acid, which is in contact with the positive electrode, oxygen, water and vapour of
nitrous acid are developed, whilst the sulphuric acid contained in the adjoining
compartment of the element absorbs through the porous diaphragm the free water
of the nitric acid and of course also a part of the diluted nitric acid; whereby in
the last compartment a mixture of sulphuric acid with nitrous acid containing
some oxygen and water is formed. The oxygen becomes free and the absorbed
water still further dilutes the sulphuric acid; the longer this process goes on, the
more the volume of the sulphuric acid increases. The quantity of the sulphuric
acid originally introduced into the element ought therefore to be so calculated,
that, on absorbing a considerable part of the water and of the nitric acid through
the porous diaphragm separating the said two acids, and some more water through
the diaphragm separating the nitric acid from the compartment containing the
negative electrode, the mixture thus obtained of sulphuric acid, water and nitrous
acid will have risen to such a level that it reaches the top of the separating
diaphragm and overflows into the compartment containing the positive electrode,
whereby the volume of the acid contained in this compartment is constantly
completed. On the other hand the sulphuric acid is dializing into the compartment
containing the solution of common salt or some alkaline solution, whereby the
negative electrode immersed in that solution becomes surrounded with sulphate of
soda; the chlorine becomes free, partly enters in combination with the zinc and
forms chloride of zinc, and partly escapes in a gaseous state. As more or less
deleterious gases are generated from the element, the outer vessel is enclosed by a
tightly fitting cover, cemented or screwed on so as to form a hermetic, joint, the
terminals of the electrodes being passed through the cover and cemented therein.

page_text: In order to prevent the pressure of the confined gases from rising to a dangerous
degree, the cover has a hole closed by a tightly fitting plug or valve, arranged to
give way when the pressure rises above a certain degree; or a cock may be
provided to be opened by hand when required.
Where a number of such elements are used together they may be enclosed by
one common cover. The hermetic joint between the cover and the vessel as also
the tops of the partitions may be conveniently made by means of caoutchouc
packing, the cover being pressed down by screw bolts secured in lugs on the outer
vessel.
A galvanic element of the above described construction gives a very constant
current; its electromotive force exceeds two "Volts" and the intensity of the
current is equal to that of a Bunsen element of the same size.