Improvements in Electrolytic Cells.
Year: 1893

page_text: Date of Application, 12th Sept., 1893-Accepted, 21st Oct., 1893
COMPLETE SPECIFICATION.
Improvements in Electrolytic Cells.
1, THOMAS CRANEY, of 624 Harrison Street, in the City of Bay City, County
of Bay and State of Michigan, United States of America, Manufacturer, de
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:―
This invention relates more specifically to the construction of electrolytic cell for
the commercial electrolysis of chlorides, such as chloride of sodium for making
chlorine and caustic soda.
The electrolysis of chlorides, such as chloride of sodium is a delicate and difficult
matter and the progress of commercial electrolysis in this particular field has met
with many obstacles. This arises largely from the presence of chlorine the intense
chemical action of which also results in the formation of hypochlorites which are
especially destructive to the anode. Carbon which is the most available material
for the anode is not exempt from this destructive action and thus while it cannot
be avoided I propose to construct the cell and carbon anode in such a manner that
the destructive action is limited and made harmless so that the permanency and
efficiency of the cell is not impaired.
To this end my invention consists in the peculiar construction of the cell, all as
more fully hereinafter described and shown in the accompanying drawings, in
which,
Fig. 1 is a vertical, central section through the anode and cathode compartments
of an electrolytic cell containing an anode of my improved construction.
Fig. 2 is a plan of the cell.
Fig. 3 is a detached, vertical section of one of the two like vessels of the cell,
the section being taken at right angles to Fig. 1.
Fig. 4 is a similar view to Fig. I with the diaphragm differently arranged.
A A' represent two like vessels or jars forming respectively the anode and cathode
compartments of an electrolytic cell.
Each vessel is formed with a lateral branch B which branches form sockets for
the ends of the bent tube C supported and suitably sealed therein. This tube is
filled with a porous medium adapted to form an electrolytic diaphragm, such as
asbestos. To hold the material in place in the tube, the latter has its lower ends
closed and provided with perforations a and an opening D is formed in the top of
the tube.
Each vessel is also provided with the lateral branches E, F, arranged to form
suitable inlet and outlet connections for feeding and discharging the liquid or
solution to be electrolized and for the escape of any gaseous products.
The cathode G shown in the vessel A' may be of any known construction, it is
supported in position in the cathode compartment by a suitable cover H which may
be sealed by means of cement V in the vessel. I have shown the cathode as formed
from a piece of sheet metal doubled upon itself.
The construction of the anode is as follows: I use an open ended tube I of
non-porous uudestructible material and which forms a non-conductor (such as
vitrified clay, stoneware or porcelain). This tube I fill with powdered gas carbon
or other dense form of pure carbon body in finely so as to make it homogeneous
carbon pencil, and if desired it may be baked in the tube all for the purpose of
making it a good conductor.
The positive terminal from the electric source of supply is carefully embedded in
this carbon and its contact with the carbon is preferably made more perfect by a
metallic enlargement T of the wire terminal.

page_text: The tube I is preferably sealed by seal U in the cover H, and is of suitable
length to extend with its upper end above the vessel and with its lower end to or
near the bottom thereof. The lower end of the tube is embedded in a body of
carbon J which fills the entire vessel from the bottom up to about the point where
the lateral branch B connects, it is preferably of powdered carbon packed tightly
around the tube I so as to make good electrical connection with the carbon in the
tube and exclude the liquid from any access thereto.
In practice the parts being arranged and constructed as described, the anode
compartment is filled with the liquid or solution to be decomposed up to the height
of the outflow F and the cathode compartment is filled to the same height, either
with the solution or with water alone or with a weak solution of the product to he
obtained. The tube C is made effective as an electrolytic diaphragm by absorbing
the liquid from the compartments by capillary attraction or some solution may be
poured into the opening D, so that the medium in the tube will absorb it.
Electrolytic action can now take place and as the solution in the anode compartment
becomes exhausted fresh solution may be added through the inlet E, whereby the
exhausted solution is displaced through the outlet F.
The product in the cathode compartment may be obtained in the same manner by
causing it to overflow through the outlet F by the addition of fresh solution or
water through the inlet E and suitable supply and receiving tanks may be
permanently provided for the purpose.
The gaseous products may readily be carried off through one of the two
connections E, F, of each compartment and be separately collected if desired.
My apparatus is thus adapted for continuous operation and the permanency of
the anode is insured as the disintegration of the carbon is now mainly confined to
the surface portion of the body J where it is of no consequence.
It is well known that it is mechanically difficult to make good carbon contacts,
but by compacting the carbon directly into the lower part of the vessel A it is
firmly held in position and cannot become displaced while at the same time the
tube I is firmly held in place, thus the electrical contact between the carbon in the
tube and the carbon in the vessel if once properly made is not likely to be broken.
By keeping the liquid out of the tube the wire terminal is also kept from corroding,
an additional safe guard the tube is preferably provided with small
perforations c above the liquid so that if by chance some gaseous product, such as
chlorine, should find its way into the tube or be formed therein, it can escape into
the space above the liquid, thus preventing it from forcing its way up the wire
terminal which would otherwise be soon corroded. The upper layer or layers of
the carbon body J may be formed if desired of coarser particles of carbon, so as to
make them permeable to the liquid, and thus reduce the electrical resistance.
but as
In the modification shown in Fig. 4, the diaphragm C projects with its lower
ends directly into the vessel A, this renders the lateral branches G unnecessary and
a single vessel divided into two separate compartments may be used instead of two
separate vessels. I consider a capillary form of diaphragm especially adapted to
accomplish the full object of my invention, as it keeps the liquids in the two
compartments better separated than a mere partition, as in case it breaks down the
liquids remain separated; it has also the advantage of being easily renewed, or
removed if it is desired to renew the anode and with a view to the latter con-
tingency the carbon body J may be formed separately in a mold of the proper
dimensions and baked solid with the tube I secure in place therein, so that the old
anode can be removed and a new one put in place without much trouble or delay.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The combination in an electrolytic cell having separate anode and cathode
compartments united by an electrolytic diaphragm, of an anode composed of carbon
compacted into a protective tube or casing extending through the liquid of the

page_text: compartment and carbon compacted into the bottom portion of the compartment
itself and around the lower end of said tube or casing, and extending to the walls
thereof, substantially as described.
THOMAS CRANEY.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.