Improvements in or connected with Means or Apparatus Employed in Electrolysis.
Year: 1891

page_text: Date of Application, 7th Apr., 1891-Accepted, 9th May,
1891
COMPLETE SPECIFICATION.
Improvements in or connected with Means or Apparatus Employed
in Electrolysis.
I ERNEST ARTHUR LE SUEUR of Ottawa Province of Ontario Dominion of
Canada 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 statement :-
The decomposition of the salts of potash and soda by an electrical current is not
new, but the decomposition of these salts for the production commercially of soda or
potash and the radical of the salt is not, so far as known to me, practised. A
sufficient reason for this is found in the large cost of the apparatus employed, its
high resistance and low efficiency and the lack of a satisfactory method for pre-
venting the escape of chlorine (which in the case of chlorides is perhaps the most
important product) as also the lack of simple and inexpensive means for removing
the liquid in the cell as well as for replacing certain parts of the apparatus which
require comparatively frequent renewal.
The object of this invention is to produce an apparatus which will obviate these
objections, which shall be durable, cheap, efficient, compact and of low resistance
and in which those parts which deteriorate in use, particularly the diaphragm and
the positive electrode, may be readily removed and replaced when desired. As the
apparatus arranged according to this invention is more especially intended for the
treatment of the chlorides of sodium and of potassium, I shall, in the following
description, refer to the said apparatus more particularly with reference to the
treatment of chloride of sodium and describe with reference to the accompanying
drawings, the best form of the said apparatus now known to me.
Figure 1 is a central vertical section and Figure 2 is a plan of a cell with the
improvements according to this invention.
Figure 3 is a perspective view of the carbon electrode removed.
Figure 4 is a plan of a tank or vessel adapted to contain liquid and of a size
sufficient to contain a number of inner cells and indicating the way in which said
inner cells may be connected up.
Figures 5 and 6 are respectively a plan view and section showing a negative
electrode detached.
Figure 7 is a plan view illustrative of the method of making the carbon electrodes
and showing the pieces of carbon placed in a cylindrical holder as also the shallow
vessel which contains the metal in which one end of each piece of carbon is
imbedded.
Figure 8 is a section on the line 8-8, Figure 7.
Figures 9 and 10 represent in side view and transverse section a piece of gas
carbon such as is taken from the inside of a gas retort and which is cut into sections
as shewn by the dotted lines in preparing it for use in the manufacture of an
electrode.
A Figure 1 is an outer tank which contains liquid the liquid being in this example
presumed to be a saturated solution of sodium chloride. B is a bell or inverted box
of earthenware or similar non corrosive material which is provided in the top with
three holes to accommodate the three metallic supports c, d, e, of the positive
electrode. The positive electrode which is shewn more clearly in Figure 3 consists
of a number of pieces of carbon, preferably gas graphite, cut to substantially
uniform length and cast in, or otherwise secured to, a backing or conducting plate
of lead or other suitable material; all as is hereinafter more fully described. The
carbon electrode requires to be lowered as the carbons are consumed by the action
in the cell while it also requires to be supported in the bell, and this is the primary

page_text: :
function of the metallic supports c, d, e, which are provided with collars f between
which and the top of the bell B are inserted filling pieces or wedges g, which serve
to support the carbon electrode in a given position. It is also necessary that there
should be an escape pipe leading from the inside of the bell for the escape of the
chlorine, a leading-in conductor for the passage of the electric current and an inlet
pipe for the admission or withdrawal of the liquid inside the bell in which the
positive electrode is partially immersed. The metallic supporting rods c, d, e are
each used for one of these inlets so that each is utilized for two functions, namely,
as a support for the positive electrode and as a means respectively for the passage
of the current, the liquid or the chlorine. The support which is marked c consists
of a leaden tube having inside it a leaden conducting pipe which passes through it
and through the backing of the electrode and into the space within the bell which
is filled with the chlorine which is formed at the positive electrode. By means of
this tube h the chlorine gas is conducted to the proper receptacle or absorbing
chamber where it is collected which may be effected in the well known manner.
The support d also consists of a cylinder or tube of lead secured to the leaden
backing of the positive electrode, and the positive conductor is placed in this
leaden tube and the tube is filled with molten metal, thereby casting the conductor
into it. The support e is also a cylinder or tube of lead which is secured to the
leaden backing of the positive electrode, and inside it is placed one leg k of a leaden
siphon which projects downwardly to a point near the leaden backing where it is
joined by means of a rubber band to a glass tube 1 (shewn in dotted lines Figure 1)
which projects downwardly into the liquid of the bell to a point as low as or slightly
below the ends of the carbons of the positive electrode. The other leg m of the
siphon projects downwardly into a vessel n of any convenient shape which is placed
outside the bell B and within the tank A. The said vessel n is filled with liquid
to the same level as the liquid within the bell and the level of which is somewhat
higher than that of the liquid in the tank A, as will be clear from Figure 1.
The conductor rises from the positive electrode to a stationary support o set inside
the tank A. as shown Fig. 2. and supporting a horse shoe magnet p the upper end
of one leg of which is hollowed out to form a mercury cup g. A lever is pivoted
to a studs set in an upright outside the tank A., see Figure 2. One end of
this lever projects over the magnet p and a finger or stud wo thereon projects
normally into the mercury cup g. The current passes through this lever con-
nection being made with it in any suitable manner, for example by securing the
positive wire to the studs. The other end of the lever r has suspended from it a
weight a' which is normally wholly, or almost wholly, immersed in the liquid
contained in the vessel n as shown Figure 1. Should the siphons act to reduce the
level of the liquid in the vessel n the strain of the weight a¹ on the lever would be
increased until the magnetic influence of the horse-shoe magnet was overcome when
the stud would be suddenly raised out of the mercury cup 1 and the circuit
broken, thus stopping the action of the apparatus. In this way the circuit is
suddenly broken at the proper time. The partial escape of the liquid within the
bell will cause the siphon to act and the circuit to be broken. If it is not desiredito
cut out the cell automatically this device may be dispensed with and the cutting
out be accomplished by the operator by means of a switch or plug which may be of
ordinary construction. As the space in the bell above the liquid contents thereof
is full of chlorine gas when the apparatus is in use, and as this gas is very
corrosive and poisonous, it is necessary to close any opening in the bell with great
care. The openings in the bell through which the tubes c d e pass are therefore
made slightly larger in diameter than the tubes and the spaces around the tubes are
filled with asphalted asbestos or equivalent material.
The mouth of the bell B is covered by a diaphragm which may be of any
suitable material (such for instance as asbestos or vegetable parchment) and
which is secured in place preferably by being clamped between the edge of the
bell and a ring s¹, which may be of lead iron brass or other suitable metal.
It is preferred to secure the diaphragm in place as follows: The upper face of the

page_text: rings which is in contact with the diaphragm, and also the edge of the bell should
be smooth and regular enough to come together with a considerable degree of
precision. The metallic rings is laid upon and is in electrical contact with the
negative electrode t which is preferably constructed of a number of layers of
iron or other suitable metal wire tape or netting. The negative wire u is con-
nected with the ring s The diaphragm lies close to both electrodes but it
is nearer the negative electrode and preferably rests thereon. I prefer that the
positive electrode should be within about one quarter of an inch of the diaphragm
and negative electrode. By using a metallic rings which is connected with the
negative electrode, as stated, and securing the diaphragm by clamping it between
said ring and the edge of the bell, the weight of the bell resting on the edge of
the diaphragm and compressing the diaphragm against the ring all leakage is
effectually prevented, because the hydrogen gas which forms at the ring, and
particularly that which forms at the upper surface thereof next the diaphragm,
operates to force the diaphragm up and hold it tightly against the edge of the
bell. This method of securing the diaphragm is simple, cheap and effective and
avoids the necessity of using a retaining ring or rings and of sealing the diaphragm
with paraffine or the like. It is to be noted however that the latter method may
be employed, that is, the edge of the bell may be tapered and a correspondingly
tapered ring be forced on over the edge, the diaphragm being between the
ring and the edge of the bell, but the arrangement described and shewn is
preferred. By placing the positive electrode over the diaphragm the latter is
kept from direct contact with the chlorine and its durability is thereby increased.
The bell is raised at one side by means of a block or in any other suitable
manner so that the diaphragm has a sufficient inclination to permit of the ready
escape of the hydrogen which is formed at the negative electrode, and the weight
of the liquid inside the bell, the level of which is considerably higher than that of
the liquid outside, serves to hold the diaphragm down and prevent it from bulging
in case any accumulation of hydrogen should take place. In this way the
diaphragm is kept flat and the escape of the hydrogen is facilitated, thus
insuring the most effective action of the cell. Morcover the excess of pressure
prevents the flow and tends to prevent the diffusion of the solution on the negative
electrode side to the positive electrode side of the diaphragm.
When the diaphragm is worn out the weight of liquid above it will rupture it,
and as soon as it is broken this liquid will escape causing the siphon to act and the
circuit to be broken as hereinbefore described. To replace the diaphragm, the
liquid is drawn off, the bell raised, the old diaphragm removed, a new one put in
position and the bell lowered again.
The upper end of the part k of the siphon is extended above the part m and serves to
receive any gas which may collect in the siphon, thus preventing its being scaled as
soon as it otherwise would be. Any well known or suitable appliance may be
attached to this upward extension of the part k for the purpose of drawing off any
gas which may accumulate therein.
For the negative electrode I have found wire netting, to be preferable to other
forins because by its use a large amount of surface is obtained which is com-
paratively free from adhering bubbles of gas, which is desirable. When a large
apparatus is used a central rivet which may also serve to secure the layers of wire
netting of the negative electrode together is arranged to project downwardly below
the level of any other portion of the electrode and is received in a mercury cup y
which is in the bottom of the large tank or vessel shewn in Figure 4 in which a
number of these inner cells or elements are placed and which may thus be connected
up in a suitable manner as shewn so that any one of the cells may be removed
without interfering with the action of the others. In such an apparatus, when
more than one inner cell is to be employed a tank or containing vessel, preferably
of a size sufficient to contain a considerable number of inner cells, as shown in
Figure 4 is provided, on the bottom of which are the cup shaped depressions y
containing mercury, one for each inner cell used and into which the projections

page_text: from the negative electrodes dip. The mercury cups make connection with the
wire surfaces collectively forming the negative electrode, and the wires from the
top of the cells make connection with the lead carbon positive electrodes collectively
forming the positive electrode; and these wires are joined up in any convenient
way to the negative and positive terminals respectively of the source of electricity.
By this arrangement in a large apparatus any one of the inner cells may be
detached and removed to replace any of its parts without interfering with the
action of the other cells. The large tank, Figure 4, is supplied with a saturated
solution of chloride of sodium and the same solution is supplied to each of the
inner cells.
An electric current being passed through the apparatus, the operation thereof is
as follows: Decomposition takes place in the chloride of sodium solution, free
chlorine and oxygen appearing at the positive electrode, rising to the top of the
bell, and passing off through the tube and its connections to the chlorine
absorbing chamber, where the chlorine is absorbed and retained which may be
effected in any one of the several well known ways. At the negative electrode frce
hydrogen is formed which is allowed to pass off and sodium hydrate is also formed
and remains in the liquid. After a sufficient percentage of the sodium hydrate has
been formed in the solution, the solution may be run off and the hydrate or caustic
soda separated from the sodium chloride which may be done in any well known
manner. As that portion of the carbon electrode which is in the liquid is used up,
the electrode is set down a proper distance into the liquid and again secured in
place by smaller filling pieces or wedges g.
In a large apparatus where a large tank is employed it will be obvious that a
single negative electrode ean if desired be used underlying all the inner cells,
and if the tank be made of iron it may also be connected with the negative wire.
If a large negative electrode is used for all the inner cells the mercury cup arrange-
ment as at У will not be needed. These changes will be obvious to those skilled in
the art and require no further description.
It will be clear that that feature of this invention which prevents the diaphragm
from bulging and thus approaching the positive electrode, namely, the higher level
of the liquid on the positive side of the diaphragm, may be utilized regardless of
the exact inclination or position of the diaphragm. By this means the diaphragm
is prevented from approaching the positive electrode whenever it is so situated that
the liquid on the positive electrode side exerts a greater pressure upon the diaphragm
than does the liquid on the negative electrode side..
It is further to be noted that the method of packing the diaphragin and preventing
leakage by utilizing the gas formed at the metallic rings which is in connection
with the negative electrode is adopted for the purpose chiefly of saving expense in
the construction of the bell or box B which contains the positive electrode and of
the ring between which and the edge of the bell the diaphragm is clamped. If
expense were of no importance the edge of the bell could be ground with great
accuracy and a ring provided which, in that case, could be of metal not connected
with the negative electrode, or of inactive material also ground with great accuracy
to accurately meet the edge of the bell so that the weight of the bell would be
sufficient to clamp the diaphragm accurately and securely and prevent leakage.
Practically, however, the method hereinbefore described, in which the bubbles of
gas are utilized to insure the packing of the diaphragm and prevent leakage, is the
most economical method and the one which is preferred.
It will be obvious that a carbon electrode can be constructed employing, instead
of the rough sided sticks of carbon, short rods of cylindrical or other regular form,
but the form of electrode shewn composed of rough-sided pieces of gas graphite
is preferred and they can be constructed as follows:-A³, Figure 9 represents an
irregularly shaped piece of gas graphite such as is taken from the inside of a gas
retort and which is hard and difficult to cut. This piece is divided by transverse
cuts a into pieces of equal length, the cut ends being smooth or practically so, that
is, the end pieces of the strip are cut as shewn at c to trim them off so that they

page_text: may be smooth and true at both ends. The sections or pieces 63 are then set on
end and packed tightly into the metal holder C³ Figures 7 and 8 which preferably
flares slightly, that is, it is slightly of frusto-conical or frusto-pyramidal shape.
The shape of this holder will obviously depend upon the shape of electrode desired.
The one shown in the drawings is circular in horizontal section and the holder is
therefore cylindrical or frusto-conical in shape. Wedges may be inserted if
required to secure the pieces 63 in the holder, and the holder and pieces of carbon
contained within it are placed in a shallow vessel e³ (Figure 8) which contains
molten lead or other suitable metal. The lead is then allowed to cool. The
vessel is taken off and the carbons and their metallic backings are separated
from the holder (Figure 7) by turning the holder over and knocking the metal
and carbons out through the top thereof. It is to enable the metal and carbons to
be thus more readily separated from the holder that the holder is made flaring, that
is, of a greater diameter at the top than at the bottom. The electrode composed
of the carbon pieces cast into the metal or leaden backing is then ready for use.
The carbon pieces are of irregular shape thus presenting a large surface, which is
desirable, and by the method described they may be prepared for use with a
minimum of cutting and at a very low cost. It is preferred to place the carbon
pieces in the molten lead as described instead of arranging them in the dish e³ and
pouring the lead around them although the latter course may be adopted.
Figures 11. 12 and 13 illustrate modifications in the arrangement wherein sealing
of the bell where the rods project through it is effected by liquid.
Figure 11 is a section corresponding to Figure 1 and
Figures 12 and 13 are details shewing modified forms.
The parts which correspond to those shewn in the preceding figures are marked
with the same letters of reference and require no further description.
In this arrangement there is used preferably one rode projecting upward from
the metal backing of the positive electrode and having a central aperture
therethrough and through the metallic backing the said aperture being for the
purpose of introducing or withdrawing the liquid contents of the bell. When
one rode is employed it must be somewhat larger and stronger than if more than
one were employed, as will be obvious. Around the aperture in the bell through
which the rode passes an annular cup is provided it being formed by the concentric
walls or upward projections m² n² which are preferably formed of the same material
as and in one with the bell B. The hole in the top of the bell through which the
rode passes is preferably somewhat larger than the rod to provide for the escape
of the chlorine which will pass up around the rod and between it and the inner
walls of the cup which walls are preferably slightly less in height than the outer
wall so that the escaping chlorine may pass over said wall ². The annular cup
is used as a lute cup to hold the sealing liquid. On the rod c and firmly secured
thereto by solder preferably, is a metallic bell shaped collar 2 which extends
outwardly from the rode and then downwardly into and below the surface of the
liquid in the lute cup. The downwardly-projectingly edge of the bell or collar
should be a sufficient distance from the bottom of the lute cup to permit of the
lowering of the electrode whenever required by the destruction of the lower ends
of the carbons of the positive electrode. Projecting from the collar p² are three
or more arms which are provided with adjusting or levelling screws the lower
ends of which rest on the top of the stoneware bell B as shewn and by means of which
the positive electrode may be raised or lowered in the bell. As will be obvious
any well known means may be employed instead of the levelling screws and the
arms for raising or lowering the positive electrode and holding it in a given
position. Wedges for example, might be employed under the arms 7² instead of
the screws. At one point on the top of the metallic bell or collar p² an
aperture is made which communicates with the interior thereof, the said
aperture being surrounded on the upper or exterior surface of the collar på by
a lute cup u, by means of which the conducting pipe which conveys the chlorine

page_text: gas to the absorbing chamber or other receptacle may be connected with the
apparatus. It will be obvious however that the chlorine escape pipe may be
connected by any well known means.
As the rod is of metal and in contact
with the backing of the positive electrode, the positive conducting wire may
be connected with the rod e or, if the collar be of metal, which is preferably
the case, the said wire may be connected either with the rod c or with said part p²
as desired.
By this device one supporting rod e will ordinarily be sufficient for cells of
the usual size or even for cells of large size but if it be desirable to use in any
case more than one supporting rod, as for example three as shewn in the
preceding figures then in that case the rode will be solid as shown Figures 12
and 13.
The passage Figure 11 through which the liquid of the bell is introduced
or withdrawn will, when the cell is in use, be securely plugged.
In Figure 12 I have shown a somewhat modified form of the device in which
the collar or metallic bell p which is soldered or otherwise secured to the rod
projects downwardly in the lute cup so that its edge rests on the bottom of the
cup and no means are employed for raising or lowering the positive electrode,
this being accomplished by chiselling or cutting away the metal of the part p²
(which is generally lead) where it joins the rod c then raising or lowering the
rod and electrode, and again soldering and sealing the part to the rod in its
new position. In Figure 13 the construction is modified by using in place of the
lute cup and sealing liquid a number of rings or washers like that shewn at a²
of asbestos paper or similar material which are tarred or otherwise suitably
treated to resist the action of the chlorine gas and which are placed underneath
the edge of the metallic bell p so that the weight of the electrode will rest
upon them and they will form a backing to hermetically close or scal the
opening to the bell B and thus prevent the escape of the gas.
The bell may be provided with an indicator communicating with its lower
part and rising to a suitable height to show the level of liquid within the bell.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
First. In an electrolytic cell a bell or inverted box of stoneware or other
non-corrosive material and a positive electrode situated within the said bell and
secured therein by metallic securing and supporting rods which pass through
apertures in the said bell and secure the said positive electrode in position therein,
substantially as hereinbefore described and illustrated.
Second. In an electrolytic cell a bell or inverted box (as B) of non corrosive
material, a positive electrode within the said bell and a diaphragm covering the
mouth of the said bell, substantially as hereinbefore described and illustrated.
Third. In an electrolytic cell a bell or inverted box of stoneware or other
non corrosive material, a diaphragm covering the mouth of the bell or box a
positive electrode placed within the said bell or box and in proximity to the
inner surface of said diaphragm, and a negative electrode secured outside the
said diaphragm in proximity to or in contact with the outer surface thereof,
substantially as and for the purpose hereinbefore described and illustrated.
Fourth. An electrolytic cell comprising the combination with a tank to contain
liquid, of a bell or inverted box in the said tank a positive electrode in said
bell or box a negative electrode below the said bell or box a metallic piece or
ring in contact with the said negative electrode and a flexible diaphragm held
between the said piece or ring and the lower edge of the said bell or box
substantially as and for the purpose herein before set forth.
Fifth. An electrolytic cell comprising a bell of earthenware, a positive electrode
therein, a diaphragm covering the mouth of said bell a negative electrode and

page_text: a tank in which said bell is placed, the level of the liquid within the bell being
higher than that of the liquid outside the bell, whereby the diaphragm is
prevented from bulging, substantially as set forth.
Sixth. An electrolytic cell comprising the combination with a tank to contain
liquid, of a bell or inverted box in said tank, positive and negative electrodes,
a flexible diaphragm between said electrodes and covering the bottom of said
bell the whole being arranged so that the liquid on the positive electrode side
of the said diaphragm is maintained at a higher level than that of the liquid
on the negative side of the said diaphragm, substantially as and for the purpose
hereinbefore set forth.
Seventh. In an electrolytic cell a bell or inverted box of earthenware or
other non corrosive material, a positive electrode therein, a negative electrode,
and a diaphragm separating the said electrodes, the said diaphragm being placed
on an incline below the positive electrode, whereby the escape of the gas formed
at the negative electrode is facilitated and the efficiency of the cell is maintained
without exposing the diaphragmn to the action of the gas formed at the positive
electrode, substantially as hereinbefore shewn and described.
Eighth. An electrolytic cell adapted to maintain the liquid which is in contact
with the positive electrode on a higher level than the liquid in contact with the
negative electrode, such cell having an outer vessel (such as that at n) containing
liquid of the same level as the liquid in contact with the positive electrode and
connected therewith, with or without means for breaking the circuit when the
level of the liquid in the outer vessel falls, substantially as and for the purpose
hereinbefore shewn and described.
Ninth. An electrolytic cell comprising the combination with a tank to contain
liquid, of a bell or inverted box of earthenware or similar inactive material, a
positive electrode within the said bell, hollow metallic supports for the said electrode,
the said supports passing through the top of said bell or box and some or all of the
said supports serving to admit the liquid to the cell, to convey the electric current
and to discharge the gas formed at the positive electrode, substantially as herein-
before set forth.
Tenth. The combination with a containing tank of a series of inner cells, each of
said cells having a bell or inverted box of non corrosive material, a positive electrode
therein and a pipe or pipes communicating with the said cell and projecting through
the said bell or box and downwardly to a level with the lowest portion of the said
electrode therein for the admission or withdrawal of the fluid of the said cell
without disturbing the liquid in the said tank substantially as hereinbefore shewn
and described.
Eleventh. An electrode for an electrolytic cell consisting of pieces of rough
carbon cut to equal or approximately equal lengths and having rough uncut sides,
and a metallic backing in which the said pieces are imbedded at one end, substantially
as hereinbefore shewn and described with respect to Figure 3 of the drawings.
Twelfth. An electrolytic cell having a bell of stoneware or similar non-corrosive
material, a positive electrode within the said bell, a supporting rod secured to the
said positive electrode and projecting through an aperture in the said bell, a collar.
or bell shaped part secured to the said supporting rod and a lute cup surrounding
the aperture in the said hell, for containing liquid into which the edge of said collar
or bell shaped part projects with or without means for raising or lowering the said
positive electrode and an opening at t in the collar or bell shaped part p² for the
escape of the gas, substantially as and for the purposes hereinbefore described and
shewn in Figure 11 and also the modifications described with regard to Figures 12
and 13.
Thirteenth. In an electrolytic cell the feeding of the positive electrode towards
the negative electrode so as to keep the distance between them substantially the
same the distance moved corresponding to the shortening of the positive electrode
during the working of the cell substantially as hereinbefore described.

page_text: Fourteenth. The general arrangement and combination of parts constituting the
electrolytic apparatus substantially as hereinbefore described and illustrated under
the various modifications in the accompanying drawings with or without the means
for breaking the circuit upon the rupturing of the diaphragm.
Dated the 7th day of April 1891.
J. H. JOHNSON & Co.,
Agents.