Year: 1897

page_text: ally united conductors leads to a conductor forming the pole of the plate. If
the said conductors are wires or cables of wires or metallic strips capable of
being strongly amalgamated they are covered at their ends (¿ª³³)* with a layer
of metal not susceptible of amalgamation, or with a suitable enamel, for the
purpose of preventing the passage of mercury by absorption from au upper con-
ductor to a lower conductor. The apertures made in the supports Bare
generally widened towards the outside so that if by accident the conductors AAA
happen to be placed at the end of the discharge in a vertical position, the drops
of mercury leaving the zinc will be collected in these cavities from which they
will re-issue and again spread themselves over the porous zinc when the con-
ductors are returned to the horizontal position. These cavities have also the
object of preventing too great a deposit of zinc at the ends of the conductors
a phenomenon well known in electrolysis. One may also with advantage con-
nect the supports together forming a rectangle by means of the pieces B¹ B¹ 60
as to form a rigid frame which supports all the conductors. Finally it is pre-
ferable to roughen the surface of the conductors or to cover them with wire gauze
in order to increase the adhesion of the mercury and of the deposited metal.
A second arrangement of the negative electrode is represented in Figures 3, 4,
and 5. The electrode is constructed of a single plate C in which are formed a
number of parallel channels c dividing the plate into ribs c. These ribs at their
ends are covered with a layer 1 of mastic or of adhesive enamel which resists acid
and which prevents the mercury from spreading by absorption from an upper
blade to a lower blade. These blades may be either formed of finely interwoven
wires forming rectangular interstices or perforated as shown in Figure 6, or they
may be pitted on their faces, the holes thus formed not passing completely
through them.
Figures 7, 8, and 9, represent a third arrangement of the plate E constructed
in a similar manner to that of the preceding modification but in which the con-
ductors or blades e are caused by twisting or by any other suitable means to be
placed horizontally in the direction of their widest face. This arrangement is
found to be the one which retains the greatest amount of mercury and adapts
itself to the most rapid charging. As in the previous pattern of plate the blades
are interwoven, perforated or cellular. Also the said blades are covered at their
ends with a layer of enamel or mastic preventing the escape of the mercury from
one blade to the other. When the plates are of a sufficiently large size I attach
upon the conductors one or more supports such as F(Figures 1 and 2) formed of
a substance not susceptible of amalgamation and which serves at the same time
to maintain a suitable separation between the negative and positive plates for
which purpose the dimensions of these supports are of course properly
proportioned
Having explained in detail my system of negative electrodes for accumulators
of lead-zine type and described in the foregoing paragraphs three principal
modifications for carrying the some into effect I will give some directions
respecting variations of my system of plates.
I usually employ a layer of zinc thicker than that which would be absolutely
necessary for the complete discharge of the negative plates, regulating the
quantity of mercury absorbed to that which is really necessary to prevent the
said layer being attacked when the circuit is open. Under these conditions,
when the normal discharge is finished the mercury remains enclosed in the pores
of the porous zinc, and has no tendency to remove from it if the conductor
remains practically horizontal. When the plate is charged the mercury
amalgamates with the zinc in proportion to its deposition upon the conductors.
In the case of a heavy surcharge, the zinc deposited being no longer combined in
Bufficient proportion with the mercury is redissolved in the acid bath, and there
remains only upon the negative plate the original quantity of zinc, that is to say,
about double the quantity which would be necessary for the capacity of the
accumulator. I would further point out that in these arrangements there is

page_text: during normal working no tendency of the mercury to descend or to rise up
along the conductora
The preceding arrangements and descriptions apply also in the case of the use
of cadmium in place of zinc, and I reserve the right of utilizing this metal,
although the high price thereof has hitherto prevented its industrial application
for this purpose.
It should also be clearly understood that I do not limit my invention expressly
to the three modifications of plates which I have described, and that the said
modifications may be varied without departing in any way from the principle of
my invention. Thus for instance a plate might be constructed with strips the
largest faces of which should be alternately vertical and horizontal thus com-
bining my section and my three described modifications. Also in one and
the same plate there might be interwoven portions and supports perforated or
pitted, and so forth.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, 1 declaro that what
I claim is:-
1. A system of negative plates for accumulators of the lead-zinc type con-
structed of zinc or of cadmium or of a suitable material covered with zinc or
cadmium, the said plates divided in sections or conductors of small height in the
shape of simple wires or of twisted or interwoven wires or of combinations of strips
either perforated or cellular, the said conductors (upon which is effected the
deposition of metal during the charge) being protected at their ends by an enamel
preventing the transfer of the mercury from one conductor to the other, and being
arranged horizontally for normal working, substantially as above described and
set forth.
2. In combination with a plate such as set forth in Claim 1 formed of con-
ductors arranged horizontally, the use of supports not susceptible of amalgama-
tion which hold the said conductors in place, and which can be provided with
cavities or orifices of any desired shape for the purpose of preventing the
electrolytic deposition from becoming more abundant at their ends, and also
for retaining in case of need the drops of mercury which may descend along the
conductors if these latter are placed vertically at the conclusion of the discharge,
the said supports serving generally to maintain a proper distance between the
plates, substantially as above described and set forth, with reference to the
accompanying drawing.
3. In a negative plate for accumulators of the lead-zinc type the use of a
porous layer of soluble metal either zinc or cadmium susceptible of retaining
a considerable quantity of mercury in its pores or in its cavities, the quantity
of metal being much greater than that which would be necessary to obtain the
normal capacity of the accumulator so that the mercury set free on discharging
will be absorbed by the underlying layers of porous metal and so that in normal
working there will be no apparent displacement of mercury.
Interdime
1000
Interme
August 1808.
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.