Improvements in Electrical Galvanic Batteries.
Year: 1895

page_text: Date of Application, 27th Feb., 1895-Accepted, 6th Apr., 1895
COMPLETE SPECIFICATION.
Improvements in Electrical Galvanic Batteries.
I, GIAMBATTISTA LAURA, of 41, Via Cavour, Turin, iu the Kingdom of Italy,
Doctor of Medicine, 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 Specification and accompanying drawing, that is to say :—
My present invention relates to that class of galvanic battery which depends
upon the use of a solution of sulphate of copper; and it has for its object to
obviate the numerous disadvantages present in all batteries of this kind hitherto
known, the principal of which are:-The easy polarization of the battery ;-
Consequent rapid diminution of the intensity of the current produced;-The great
expenditure of sulphate of copper and of zinc ;-The constant care and attention
necessary;-The difficulty and expense of construction and repair ;-The
inconvenience of moving and of transport, in which there are great risk of
breakages; and the like.
:-
The present invention has for its object, therefore, a novel method of construction
of the elements of a sulphate of copper battery, characterized substantially :-
(a.) More particularly by the use between the copper and the zinc, of a
diaphragm which is of the highest possible degree of impermeability;-replaces
the ordinary porous pot, than which it is much less costly ;-divides the single
vessel containing the element, into two parts separated by this means by an
absolutely hermetical division; allows its application to the vessel in such a
manner as to give to the element the desired solidity and stability ;-is applied so
easily that any one can make it without its being necessary to have recourse to a
special workman, either to construct the element or to re-construct it when it has
become inactive ;-of such kind in fact, that this fresh formation of the element
only becomes necessary after a time longer or shorter, according to the total amount
of energy which has been developed, but in any case, not before a year of work,
since even at the expiration of this period no traces of sulphate of copper are
found in the liquid surrounding the zinc, nor does the latter show any parasitic
deposits of copper.
(b.) And secondarily, by the combination in the element of such battery-with
the special diaphragm just mentioned-of a suitable receiver (preferably in the
shape of a globular or balloon-shaped bottle) serving as a store for the sulphate of
copper (that is to say, the depolarizer), and consequently, allowing the battery to
operate, by itself, and without attention or care, for a time of great length and
proportionate to the quantity of the depolarizer in the said bottle.
After numerous experiments with different substances for the composition of
this novel diaphragm, the inventor has adopted powdered marsh-mallow ("althæa")
mixed with a saturated solution of chloride of sodium, so as to form a stiff paste.
This diaphragm is not only the most impermeable of any known, but it is almost
entirely impervious to the passage (through its mass) of sulphate of copper, and
thus almost entirely prevents the deposit of the latter upon the zinc. The
polarization of the battery is consequently so small and so slow, that it affords the
favourable results explained above. Moreover, by forming the diaphragm of a
greater or less thickness, batteries of greater or less interior resistance can be
obtained, in which currents of less or greater intensity according to the different
applications for which they are required, are generated.
The accompanying drawing represents in axial vertical section, one element of
a battery constructed according to the present invention. Of course, the element

page_text: may not only be made of different sizes but also of different shapes, according to
the purpose to which it is to be applied, without in any way affecting the nature
and substantial characteristics of the invention.
V is the external vessel (of any suitable form, but supposed to be cylindrical in
the drawing) containing the clement, as usual in all liquid batteries;-C is the
copper (consisting of a plate of a shape suitable to that of the vessel, a disc in
the drawing), which has soldered to its centre one of the conducting wires c', the
disc resting on the bottom of the vessel;-t is a glass tube of suitable diameter,
the lower edge of which is serrated or raised somewhat above the copper C in order
to allow the solution in the central reservoir to run into the vessel ;-D is the
diaphragm, the composition of which will be hereinafter described ;-Z is the zinc
(also of a shape adapted to the vessel,-cylindrical in the drawing), which has a
central opening to allow the passage of the tube t, and has an extension or
projection above, to which is soldered the other conducting wire d;-B is the
reservoir for the depolarizer (of any suitable shape globular or balloon shaped in
the drawing); it rests upon the upper edge of the tube t, and is provided below
with a neck a which passes down the tube, and the mouth of which is closed by
a stopper of wood or other suitable substance, through which pass two small
glass tubes, y.
g
The diaphragm is supported upon the bottom of V at a height which may be
varied as found advisable, (for instance, about 1 centimètres), either by a slight
contraction v in the outer vessel V, or by small supports of wood or other suitable
substance, arranged round the edge of the bottom of V. It is composed of two
superposed thicknesses, the lower one S consisting of very fine sawdust, and the
upper one of powdered marsh-mallow ("althwa "), both mixed with a saturated
solution of chloride of sodium, and held in place by the three divisions, (the lower
one d', intermediate one d², and upper one d³), which are fitted exactly to the shape
of the section of the vessel, and are each formed of a piece of thick cloth the
edge of which is sewn upon a light ring of cane, or other suitable material
sufficiently flexible to allow it to be bent to the exact shape required. Both the
diaphragms S, A, and the divisions d', d, and , bave an opening at their centre
to allow the tube t to pass through them. The height (or thickness) of the entire
diaphragm is about two to five centimètres; but of course it may be made more or
less strong according to the special application for which the cell of the battery is
intended.
The putting together of the cell is extremely simple. The plate of copper C is
placed at the bottom of the outer vessel V, the tube t is arranged in the centre of
the vessel, the conducting wire e passing through it, the partition d' is then fitted
in place by passing it over the tube t, round which it should fit exactly,-
which is facilitated by its central opening being of slightly less diameter than
that of the tube upon which it is pressed with a uniform pressure, and it is
pushed down until it rests upon the contraction of the outer vessel or upon the
small supports already described; the solution of sulphate of copper is then
poured into the tube until it fills the space in the outer vessel below d' and wets
the latter, the sawdust prepared as already described is then placed upon and is
pressed well down so as to make it adhere uniformly to the cloth, the partition d²
is then applied in the same as d', and upon it is then placed the paste or compound
of prepared marsh mallow in the same way as had been previously done with the
sawdust, and finally the upper cloth partition is applied in the same manner as
and d²; and upon d³ is then placed the zine Z, round which is poured a saturated
solution of chloride of sodium, and, finally, the neck a of the reservoir B (which has
been previously filled with pieces of sulphate of copper and solution of the same
salt, and has been closed with a stopper, as already explained), the conducting
wire c passing up by the side of the tube.
In order that the putting together of the apparatus may be perfect, it is
sufficient to take great care that no trace of air remains between the liquid
surrounding the copper and the lower face of the diaphragm, or in any of the parts

page_text: of the latter. This result,-to succeed in which is the only delicate part of the
operation, is obtained easily enough by taking care to pour in sufficient of the
solution of sulphate of copper to saturate, as already explained, the lower cloth
partition or disc d', and to allow sufficient time for this purpose; a slight excess of
the liquid will not be injurious as it will be afterwards forced back into the central
tube by the introduction and compression of the sawdust. As this last has for its
principal object the formation of a bed upon which may rest the diaphragm
properly so called, consisting of the layer of marsh-mallow paste, it will be as well
not to compress the sawdust too much but to leave it, ou the contrary, somewhat
lightly pressed in order that the liquid surrounding the copper may be better
able to saturate it, and more easily come in contact with the marsh-mallow
diaphragm.
The electro-motive force of an element such as that described is 0-8 volts; the
interior resistance and its intensity may be varied as desired. I have constructed
cells in which such interior resistance has equalled 5, 2, 1, or 0.5 ohms, and the
intensity has equalled 0.1, 0.2, 0.6, and 1 ampère. In fact, this element gives a
current of very great constancy, so that practically, no variation is observed, either
in the electro-motive force or in the interior resistance of one of these elements
for fifteen together.
kept constantly in short circusxpressly to days togect arrangement described and
shewn, of the element and of its different parts, one or more of which accessory
parts may be omitted as may be found desirable, but,
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
==
1. In galvanic batteries using two liquids, the new element characterized
essentially by the use of a vessel (into which the two electrodes dip in the
usual way), single, but divided into two parts (adjoining each other, but
preferably one above the other), by a partition fixed to the vessel so as to be
sufficiently strong to avoid all risk of displacement and breakage in transport, and
taking the place of the ordinary porous pot which is no longer required, and,
unlike the latter, impermeable to such an extent as to prevent, entirely, or almost
entirely, the liquid surround the positive electrode from coming in contact with the
negative electrode.
2. In the element of a galvanic battery using two liquids, as claimed in Claim 1,
the novel diaphragm, characterized essentially by the use in its composition of the
powder of marsh-mallow ("althæa "), mixed to a paste in a saturated solution
of chloride of sodium, the said paste being applied in such a manner as to give to
the said diaphragm a nearly absolute impermeability by the presence in it of the
marsh mallow.
3. In the clement of a galvanic battery using two liquids, as claimed in
Claim 1, the combination, with the diaphragm as claimed in Claim 2, of the reservoir
for the depolarizer, of any suitable form but preferably in the form of an
inverted globe, communicating with the vessel containing the positive electrode.
All substantially as and for the purposes described and illustrated.
Dated this 27th day of February 1895.
EDWARDS & Co.,
65 and 66, Chancery Lane, London, Agents for the Applicant.