Improvements in Galvanic (Cells.
Year: 1887

page_text: Improvements in Galvanic (Cells.
I, NELSON WILLIAMS PERRY, of Norwood, County of Hamilton, and State of Ohio,
United States of America, Mining Engineer, do hereby declare the nature of my
invention for TMPROVEMENTS IN GALVANIC CELLS, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:-
The object of my invention is to produce an open circuit cell that will not polarize;
also to accomplish for single liquid batteries in general, in the way of depolarization,
what has heretofore been accomplished only by a second liquid.
My Conducting electrode is carbon, and in the form in which I use it, it accom-
plishes its own depolarization. I make use of the well known property of porous
carbon, viz: the property of condensing or occluding within its pores the various
gases. If one of these gases be oxygen it acts upon the other gases in the same way
as does nascent oxygen or ozone. This is the first feature of my invention.
This porous carbon exposes to the battery liquid a much larger surface than can be
obtained in any other way within a given space, and will therefore, in itself, be an
electrode superior to the usual donse carbon electrode of whatever shape it may be
made. If a piece of porous carbon be immersed in the battery liquid, this liquid
comes in contact with the boundary of each little pore in the carbon mass, in this
way making the electrical surface of the carbon equal to the sum of the surfaces of
the pores, and the exterior of the carbon thereby obtaining the greatest possible
surface in the least possible volume of the carbon. This is the second feature of my
invention.
If, however, the porous carbon be completely immersed in the battery liquid, and
the circuit be closed, polarization is merely a question of time, as there can be no
renewal of-the oxydizing agent, viz.: oxygen from the.air.

page_text: Therefore, another feature of my invention has reference to enabling the porous
carbon to be a constant means for depolarization, and this feature of invention consists
in such arrangement of the porous carbon, that while one side or portion of the carbon
is in contact with the battery liquid, the other side or portion is exposed to the air.
By this arrangement the porous carbon is occluding the polarizing gases on one side,
and occluding the depolarizing agent, oxygen, from the atmosphere, on the other side.
In this way I obtain a constant and inexhaustible supply of a depolarizer.
As the internal resistance of a galvanic cell, is (other things being equal) pro-
portional to the distance apart of the two electrodes, or in other words, is proportional
to the resistance of the conducting fluid, it is desirable to place the two electrodes as
near together as possible. Practically, the best results have been obtained by a
considerable separation of the two-the better circulation of the battery liquid thereby
obtained compensating for the loss due to their further separation.
In my device, (as will be fully set forth further on) I have succeeded in making
the mathematical axes of the two clectrodes coincident, at the same time having
sufficient actual space between the electrodes to allow free circulation of the battery
fluid. In this way, since each electrode may be considered as acting in its mathe-
matical axis alone, I have the electrodes coincident without interfering with the
circulation of the battery fluid.
Another feature of my invention therefore, consists in the arrangement of the
generating electrode and of the conducting electrode, so that the mathematical axis
of the generating electrode shall be coincident with the mathematical axis of the
conducting electrode.
Where the porous carbon is placed horizontally, and partly immersed in the battery
fluid, its tendency is to draw to the upper surface by capillary attraction, the battery
fluid, which, upon evaporation, deposits its salts, and eventually stops up the pores,
thereby precluding the possibility of occlusion of atmospheric oxygen which is to act
as the depolarizing agent. To prevent this action due to capillary attraction, I apply
to the upper surface of the porous carbon a substance not wetted with the battery
fluid, which opposes the capillary attraction. A grease of some kind meets this want
most fully, as it is not wetted by any of the battery liquids now in use, except alkaline
solutions, which may saponify it.
For this purpose I prepare a substance that is solid at ordinary temperatures, such
as paraffine. In applying it to the upper surface of the carbon, care must be taken
not to close the pores, else the efficiency of the carbon as an occluder of oxygen, and
consequently as a depolarizer, will be destroyed. Another feature of my invention,
therefore, is the application to one side of a piece of porous carbon, of a substance not
wetted by the battery fluid, and which therefore opposes capillary attraction.
In addition to the means already set forth for preventing and correcting polari-
zation, another feature of my invention consists in means whereby the conducting
electrode is arranged to collect the polarizing gases, and mechanically to disperse
them.
In the accompanying drawings forming part of this specification :-
Fig. 1, is a vertical central section of my improved cell.
Fig. 2, is a top view of same.
Fig. 3, is a view of the under side of the carbon element with its attachments.
Fig. 4, is a view of the under side of the carbon element, which is provided with
corrugations, instead of the depressions shown in fig. 3.
The containing vessel or cell A, is preferably made of glass, and may be either
circular, or square in cross-section, the latter form being preferred.
The conducting electrode C, is made of porous carbon. In outline, it preferably
conforms in shape to that of the containing vessel, and is flat, being of such thickness
as will best enable it to perform its functions.
This conducting electrode, in the preferred form of the element as illustrated, is
located at the surface of the battery fluid, and preferably has its upper surface out of
the fluid in direct contact with the atmospheric air. To enable it to maintain this

page_text: position with the varying level of the fluid, means are provided to float it on the surface
of the fluid. The preferred means of accomplishing this is that illustrated in fig. 1.
A number of corks a, of sufficient buoyancy to float the carbon, are provided. The
carbon is mounted on these corks by means of the stems a³, which are made of wood
or other nonconducting material, not acted upon by the battery fluid. While the
corks form the preferable mode of supporting the carbon, other means may be provided;
but it is essential that the buoyant body be not affected by the battery liquid, in order
not to induce secondary currents within the cell.
The under surface of the carbon is provided with a number of depressions or
corrugations b. The tubules c extend entirely through the carbon. An opening c!
is cut through the center of the carbon. The generating electrode is preferably zinc,
but other metals which the battery liquid is capable of acting upon, may be substituted.
It is intended to have the axis of this generating electrode coincide with the axis of
the conducting electrode C. To accomplish this object, I pass the positive element
through the center of the opening c², and maintain it in a vertical position, that is to
say, at right angles to the surface of the horizontal floating plate C.
Preferably the bar Z, the generating electrode, rests on the bottom of the jar in a
seat S, which prevents displacement of its lower end. The upper end of the bar is
supported by the cap B, through which it passes loosely.
The cap or cover of the cell is preferably made in two parts B and B³, as shown in
figs. 1 and 2, so as to allow ready access to the cell.
To prevent the bar Z from coming into electrical contact with the conducting
electrode, the upper portion of the bar within the cell is insulated in any suitable
manner.
The upper end of the bar Z is fashioned into a binding post, and is provided with a
binding screw N for the attachment of a wire. The binding post P¹ is secured to the
top of the piece B₁ of the cover; it is provided with a vertical opening p, communi-
cating with the interior of the cell, and into which the platinum wire E passes, and is
there clamped by the binding screw P. The upper part of the post P1 is provided
with another binding screw P for the attachment of the conducting wire. The wire E
is coiled so as to allow the rise and fall of the carbon plate. The method of
attachment of this platinum wire to 'the carbon, is not important beyond securing
good electrical contact.
For the purposes already mentioned, the upper surface of the carbon, which is just
above the surface of the fluid, is preferably smeared with a hard fat or wax, such as
stearine or paraffine. This covering of the top of the carbon with a substance not
wetted by the battery fluid performs a very important function which will be fully
explained further on." As one means illustrative of the application of the principle,
mention the use of a saturated solution of Ammonium chloride as the battery fluid.
The operation of the battery is as follows: When the circuit is closed the battery
acts, electricity is developed, and the salt in solution, viz.: the Ammonium chloride, is
decomposed. In this decomposition the acid radical of the ammonium chloride,
enters into combination with the zinc to form zinc chloride, while the other products
of the decomposition, viz: Ammonia gas and perhaps hydrogen are liberated on the
carbon, and a certain degree of polarization would be expected, but polarization is
prevented in my cell, in the following manner :-The carbon is porous and has
the property of occluding gases within its pores; being continually exposed to the
atmosphere, an abundant supply of oxygen is provided, and is occluded within
the porous carbon. This Oxygen unites with the electro positive ements of the
decomposition as fast as they are liberated on the carbon, and in this way polarization
is prevented. The depressions or corrugations b, and the tubules c, act as collectors
and avenues of escape for the polarizing gases, and thus mechanically assist in
preventing polarization.
'
In consequence of the porosity of the carbon, capillary attraction draws the battery
fluid into the carbon, whose effective electrical surface is in this way multiplied
enormously, as previously explained,

page_text: The continued action of this capillarity would however, be unfortunate, as it would
result in some of the fluid collecting on the top of the carbon plate, where the water
would evaporate, and leave the salt to mechanically stop up the pores of the carbon,
thus interfering with its depolarizing action. To avoid this condition, the use of the
stearine or paraffine, is resorted to. Such substance is applied to the top of the
carbon in such small quantity and in such manner as not to clog up the small pores,
and thus prevent the occlusion of the oxygen: yet nevertheless, it does prevent the
deposit of battery salts on the top of the carbon plate.
The axes of the two electrodes being coincident, so much of the internal resistance
as is due to separation of the elements, is eliminated, because these elements act as if
their whole action was concentrated in their mechanical centers.
When a cell has continued long in action, crystals form on the generating electrode,
and tend to reduce the effective electrical surface. On trial of my cell, I have found
these crystals to form only after the expiration of a very long period, much longer
than that at which they appear in the Leclanche cell, and moreover they have formed
on the zinc only below the level of the bottom of the corks, and to some slight extent,
on the corks themselves. By coating the corks with paraffine this crystalization on
them is prevented, and at the same time, the corks are rendered much more durable.
As the water evaporates from the fluid, the floating carbon sinks, and thus maintains
the proper relations of the parts of the cell. It is well to have an excess of the
ammonium chloride in the cell so that the fluid may be renewed by the addition of
water alone.
This battery is peculiarly constant and continuous in action; it presents a minimum
of internal resistance, and polarization is almost impossible. Its mechanical features
are such as make it cheap in price, easy of repair, certain in action, and not liable to
derangement.
While the various features of my invention are preferably employed together, one
or more of said features may be employed without the remainder; and in so far as
applicable, one or more of said features may be employed in connection with galvanic
cells, of a description other than that herein specifically set forth.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed, I declare that what I claim is :-
(1). An electric cell in which the conducting electrode. is a plate floated on the
surface of the fluid, substantially as and for the purposes specified.
(2). An electric cell in which the conducting electrode is a plate floated on the
surface of the fluid, and provided with opening's for the escape of the polarizing gases,
substantially as and for the purposes specified.
(3). An electric cell in which the conducting electrode is a plate of porous carbon,
floated upon the surface of the fluid, as and for the purposes specified.
(4). As the conducting electrode in an electric cell, a horizontal floating plate of
porous carbon, substantially as and for the purposes specified.
(5). As the conducting electrode in an electric cell, a plate of porous carbon, one
surface of which is coated with a substance not wetted by the battery fluid, substantially
as and for the purposes specified.
(6). The horizontal plate of porous carbon C, provided with tubules c, as and for
the purposes set forth.
(7). The horizontal porous carbon plate C, provided with tubules c, and having its
upper surface covered with a substance not wetted by the battery fluid, substantially
as and for the purposes specified.
(8). The horizontal porous carbon plate C, provided with depressions or
corrugations b, and tubules c, as and for the purposes set forth.
(9). The porous carbon plate C, provided with depressions or corrugations b

page_text: C,
and having its upper surface covered with a substance not wetted by the
tubules
battery fluid.
(10). As an electrode in a battery cell, a porous carbon in combination with a
buoyant body to float the same, as and for the purposes specified.
(11). The porous carbon plate C, in combination with the corks a, substantially as
and for the purposes specified.
(12). The combination of the cell A containing a saturated solution of ammonium
chloride, the carbon plate C, buoyed by corks, and zinc bar Z passing vertically
through the center of the carbon plate, substantially as and for the purposes specified.
Dated the 11th day of January 1887.
Witnesses:
W. P. GULICK.
F. J. CowE.
NELSON WILLIAMS PERRY.