Improvements in Electrolytical Apparatus.
Year: 1892

page_text: Date of Application, 9th Nov., 1892
Complete Specification Left, 26th May, 1893-Accepted, 23rd Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Electrolytical Apparatus.
A communication from Dr. OSKAR KNÖFLER, officially appointed Chemist, and
FR. GEBAUER, both of Charlottenburg, in the Empire of Germany.
I, ALFRED JULIUS BOULT of 323 High Holhorn in the County of Middlesex,
Member of the Institution of Mechanical Engineers, do hereby declare the nature
of this invention to be as follows:-
:―
The apparatus herein described is intended for the technical electrolysis of
solutions of all descriptions especially aqueous solutions of chlorides of metals for
the purpose of obtaining bleaching solutions and it is so arranged as to occupy
little room and require little electrical energy for its operation so that it may be
utilized in comparatively small plants and enables high tension currents to be
employed. It may for example be without any difficulty connected to any electric
lighting plant, however high the tension of current may be with which it is operated.
It is also possible to employ a dynamo which during the night is employed for
lighting, for operating the present apparatus for electrolytic purposes during the
day and it is mainly intended for establishments or factories where paper is
manufactured or bleached, for the preparation of the required bleaching solution.
The apparatus mainly consists of electrodes in the shape of plates separated by
insulated intermediate frames. These electrodes may be made of sheet-metal or
consist of plates of carbon, manganese ore, (brownstone), peroxide of lead, or the
like or they may be made of iron, preferably coated with hard rubber, or of
ceramic material, such as clay, glass, etc., or of celluloid, impervious wood, or the
like. The electrodes and frames are preferably of either round or angular shape,
and when joined, form a series of closed divisions or chambers adapted to receive
the solution to be treated by electrolysis.
The plates and frames are arranged in a supporting frame not unlike that used
for filtering presses, and these frames and electrodes have lateral lugs or projections
by means of which they are supported upon guide-rods or rails insulated by means
of a lining or covering of hard rubber or the like. Two terminal plates and a
spindle, similar to those used in filtering presses serve for compressing this series of
electrodes and the joints between the frames and plates are made tight by means of
indiarubber, asbestos or the like.
Each of the frames is provided with a cock or tap through which the liquid
to be electrolysed is admitted, and also with an outlet through which the liquid
is discharged in corresponding quantities. A distributing pipe supplies all the
divisions or compartments simultaneously with the fresh solution, while the liquid
that has undergone electrolysis is conducted away by a channel provided for the
purpose.
The solution to be decomposed in this manner may also be circulated transversely,
or in other words, it may be conducted from one compartment to another, and not
discharged till it has passed the last compartment.
Instead of being arranged after the style of a filtering press the electrodes and
frames may be also arranged in the shape of boxes, somewhat like Cruikshank's
current generating batteries in which case the frames form one connected whole
with the case or box.
Instead of employing separate plates as before stated, each plate may be integral
with its frame; the electrodes being in this case provided on both sides with.a
projecting edge so that by the simple juxtaposition of such plates a row of compart-
ments, similar to those described above is formed. Or each electrode-plate may be

page_text: on one side only rigidly connected with the frame, so that frames are obtained
which are open on one side and closed on the other by its plate.
Whichever of the above mentioned arrangements is given the preference it is in
all cases necessary that each electrode should combine both poles in its operation.
Whether therefore it consists entirely of homogeneous material, or is composed of
different materials, it must at all events act as an anode on one side and as a cathode
on the other.
This feature is the chief improvement this apparatus offers, and in order to carry
it out the electrodes are here arranged, not as they have been in the electrolytic
decomposing apparatus hitherto used, viz. parallel to each other, but so as to be
operated by tension, only the first and last plate of each series being connected each
with one
pole of the source of electricity. The current is thus conducted only
through the liquid between the electrodes and throughout the whole surface of the
Jatter, and in each case the sides turned towards the positive electrodes form
cathodes, and the sides turned towards the negative electrodes, anodes. Thus each
of the compartments formed jointly by the electrodes and frames and filled with
liquid to be electrolysed forms an electrolytic decomposing cell, and in each
electrolysis takes place according to Faraday's law.
The electro-chemical production or yield is in all cases the same and will increase
(assuming that the strength of current is the same for all cells) exactly in a
predetermined proportion as the cells are in succession included in the circuit i.e.
according as the tension of current becomes more powerful.
It will be understood that in one apparatus more than one series or row of
electrodes may be operated by tension in the manner described, the two, three or
more additional rows being parallel to the first.
The switching method above suggested offers the great advantage that tensions
of any required magnitude may be employed while formerly the electrolytic process
could only be carried out with a low tension, comparatively high tensions having
only been serviceable in large plants, where a number of apparatus could be switched
into the circuit in succession.
The described arrangement will prove particularly advantageous in the special
case of platinum electrodes. It is a well-known fact that the attempt made to
introduce platinum into general use as a material for electrodes has been frustrated
by the enormous cost involved in the construction of apparatus with such electrodes.
In consequence of the manner in which electrolytic apparatus have been operated
hitherto, it was necessary that the electrode-material should have a very large
sectional area in proportion to its surface so that the current might be sent into the
electrolyte without too considerable loss of tension. Other materials coated or
lined with platinum have also proved failures. But in the present apparatus the
whole of the surface forms the current-conducting area and therefore platinum
plates not exceeding one millimetre in thickness may be employed; plates in fact
through which in the old arrangements only a small number of ampères could be
sent while here currents representing hundreds of ampères may be employed. One
gramme of platinum with a surface of 100 square centimetres will on an average
admit of the economical employment of 10 or more ampères.
The method of operating this apparatus also offers the advantage that all contact
pieces are dispensed with, thus doing away with all the trouble connected with
keeping them in repair. Even very large electrodes may according to this invention
be readily composed of smaller ones which in the same way as large window-panes
have in former times and not unfrequently are still composed of a number of small
glass plates. The idea is extremely simple in itself, but what has prevented its
being carried out in practice hitherto is that in consequence of the old method of
employing the current it was necessary for the different plates of say carbon,
platinum or the like to be connected so as to form a conductor. It was therefore
necessary to make the frames of metal or some other electrical conductor and such
material was generally very soon destroyed by the electrolysis.
The present method of operation admits of the frames connecting the different

page_text: plates being made of non-conducting material such as hard rubber, celluloid,
glass, clay, or the like, or it may be made of metal and covered or coated with
some such material, so that their construction is greatly facilitated. For example
the electrode may be set in a frame made of non-conducting material such as
hard rubber, celluloid clay glass or the like, or of metal such as iron, copper
or the like covered or coated with such non-conducting material, somewhat after
the style of a window; or a number of plates may be joined together by means
of sulphur, cement, or the like or by simple juxtaposition and subsequent
framing so as to form one casement-like series or large plate.
Hitherto compartments have been devised without diaphragms, but apparatus
can also be used in connection with diaphragms and in that case the diaphragms
may be arranged exactly in the same manner as the electrode plates.
Dated this Ninth day of November 1892
ALFRED J. BOULT,
Chartered Patent Agent.
COMPLETE SPECIFICATION.
Improvements in Electrolytical Apparatus.
A communication from Dr. OSKAR KNÖFLER, officially appointed Chemist, and
FR. GEBAUER, both of Charlottenburg, in the Empire of Germany.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered Patent Agent, 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 apparatus herein described is intended for the technical electrolysis of
solutions of 11 descriptions especially aqueous solutions of chlorides of metals,
for the purpose of obtaining bleaching solutions, and it is so arranged as to occupy
little room and require little electrical energy for its operation, so that it may
be utilized in comparatively small plants and enables high tension currents to be
employed. It may for example without any difficulty be connected to any electric
lighting plant however high the tension of current may be with which it is
operated. It is also possible to employ a dynamo, which during the night is
employed for lighting, for operating the present apparatus for electrolytic purposes
during the day and it is mainly intended for establishments or factories where
paper is manufactured or bleached, for the preparation of the required bleaching
solution.
The invention will be best understood by reference to the accompanying drawings
in which
Figures 1 and 2 are respectively a side and end elevation of one form of the
apparatus constructed according to this invention.
Figures 3 and 4 are transverse vertical sections of the apparatus taken through
an intermediate frame, Figure 4 showing a frame of somewhat modified form to
that shown in Figure 5; both these figures are drawn to a scale smaller than that
to which Figures 1, 2 and 5 to 10 are drawn.
Figure 5 is an elevation of one of the electrode-carrying frames.
Figure 6 is an elevation of a circular electrode carrying frame, and
Figures 7, 8, 9 and 10 are transverse sections through electrode carrying frames
of various constructions.
Like letters indicate like parts throughout the drawings.
The apparatus mainly consists of electrodes A. in the shape of flat plates, such as
shown in Figures 1 and 7 separated by insulated intermediate frames B. These
electrodes may be made of sheet-metal, or consist of plates of carbon, manganese,
(brownstone), peroxide of lead, or the like, or they may be made of iron, preferably
coated with hard rubber, or of ceramic material such as clay, glass, etc. or of

page_text: celluloid, impervious wood, or the like. The electrodes A and frames B are
preferably of either round as shown in Figure 6 or angular shape as shown in
Figures 2 to 5, and when joined as in Figure 1, form a series of closed divisions
or chambers B¹, Figures 3 and 4, adapted to receive the solution to be treated by
electrolysis.
The plates or electrodes A. and frames B are arranged in a supporting
frame CC, Figures 1 and 2, not unlike that used for filtering presses and these
electrodes and frames have lugs or projections A and B respectively by means of
which they are supported upon guide rods or rails C¹ insulated by means of a lining
or covering (not shown in the drawing) of hard rubber or the like. Two terminal
plates D and E and a screwed spindle E similar to those used in filtering presses
serve for compressing this series of electrodes A, and the joints between the
frames B and plates or electrodes A are made tight by means of indiarubber,
asbestos, or the like.
Each of the frames B is provided with a cock or tap B³ through which the liquid
to be electrolysed is admitted, and also with an outlet B' through which the liquid
is discharged in corresponding quantities. The outlet B4 may either consist of a
pipe connected to the bottom of the frame B and extending to near the top of it as
shown in Figure 3 or it may consist of a bent pipe such as B4 connected with one
side of the frame B as shown in Figure 4. A distributing pipe F supplies all the
divisions or compartments B¹ simultaneously with the fresh solution while the
liquid that has undergone electrolysis is conducted away by a channel G provided
for the purpose.
The solution to be decomposed in this manner may also be circulated transversely
or in other words it may be conducted from one compartment B' to another and
not discharged till it has passed the last compartment.
Instead of being arranged after the style of a filtering press, the electrodes and
frames may be also arranged in the shape of boxes, somewhat like Cruikshank's
current generating batteries, in which case the frames form one connected whole
with the case or box.
Instead of employing separate plates or electrodes A as before stated, each
electrode may be integral with its frame B; the electrodes being in this case
provided on both sides with a projecting edge, so that by the simple juxtaposition
of such plates a row of compartments, similar to those described above is formed.
Or each electrode-plate may be on one side only rigidly connected with the frame,
so that frames are obtained which are open on one side and closed on the other by
its plate.
Whichever of the above mentioned arrangements is given the preference, it is in
all cases necessary that each electrode A should combine both poles in its operation.
Whether therefore it consists entirely of homogeneous material, or is composed of
different materials, it must at all events act as an anode on one side and as a
cathode on the other.
This feature is the chief improvement this apparatus offers, and in order to
carry it out the electrodes are here arranged not as they have been in electrolytic
decomposing apparatus hitherto used viz. parallel to each other, but so as to be
operated by tension, only the first and last plate of each series being connected
each with one pole of the source of electricity. The current is thus conducted
only through the liquid between the electrodes and throughout the whole surface
of the latter, and in each case the sides turned towards the positive electrodes
form cathodes, and the sides turned towards the negative electrodes, anodes.
Thus each of the compartments formed jointly by the electrodes and frames and
filled with liquid to be electrolysed forms an electrolytic decomposing cell and in
each electrolysis takes place according to Faraday's law.
The electro-chemical production or yield is in all cases the same and will
increase (assuming that the strength of current is the same for all cells) exactly
in a predetermined proportion, as the cells are in succession included in the
circuit, i.e. according as the tension of current becomes more powerful.

page_text: It will be understood that in one apparatus more than one series or row of
electrodes may be operated by tension in the manner described, the two, three or
more additional rows being parallel to the first.
The switching method above suggested offers the great advantage that tensions
of any required magnitude may he employed, while formerly the electrolytic
process could only be carried out with a low tension, comparatively high tensions
having only been serviceable in large plants, where a number of apparatus could
be switched into the circuit in succession.
The described arrangement will prove particularly advantageous in the special
case of platinum electrodes. It is a well-known fact that the attempt made to
introduce platinum into general use as a material for electrodes has been
frustrated by the enormous cost involved in the construction of apparatus with
such electrodes. In consequence of the manner in which electrolytic apparatus
have been operated hitherto, it was necessary that the electrode-material should
have a very large sectional area in proportion to its surface, so that the current
might be sent into the electrolyte without too considerable loss of tension. Other
materials coated or lined with platinum have also proved failures. But in the
present apparatus the whole of the surface forms the current conducting.arca, and
therefore platinum plates not exceeding one millimetre in thickness may be
employed plates in fact through which in the old arrangements only a small
number of ampères could be sent while here currents representing hundreds of
ampères may be employed. One gramme of platinum with a surface of 100 square
centimetres will on an average admit of the economical employment of 10 or more
ampères.
;
The method of operating this apparatus also offers the advantage that all contact
pieces are dispensed with, thus doing away with all the trouble connected with
keeping them in repair. Even very large electrodes may according to this
invention and as shown in Figures 5, 6, 8, 9 and 10 be readily composed of smaller
ones which in the same way as large window panes have in former times and not
unfrequently are still composed of a number of small glass plates.
In these figures A represents the electrode plates and A2 the frames into which
they are fitted. In Figure 8 the plates A are fitted between two frames in
Figure 9 let into one side of the frame and in Figure 10 supported centrally in a
frame A narrower than the electrodes A. Each of these devices as also that
shown in Figure 7 which consists of a large plate A with a thin frame A² on each
side, when in use has a frame B on either side of it.
The idea is extremely simple in itself, but what has prevented its being carried
out in practice hitherto is that in consequence of the old method of employing the
current, it was necessary for the different plates of say carbon, platinum, or the
like, to be connected so as to form a conductor. It was therefore necessary to
make the frames of metal or some other electrical conductor, and such material was
generally very soon destroyed by the electrolysis.
The present method of operation admits of the frames connecting the different
plates being made of non-conducting material such as hard rubber, celluloid, glass,
clay or the like or it may be made of metal and covered or coated with some
such material, so that their construction is greatly facilitated. For example the
electrode A may be set in a frame A² made of non-conducting material such as hard
rubber, celluloid, clay, glass, or the like, or of metal such as iron, copper or the
like covered or coated with such non-conducting material, somewhat after the style
of a window; or a number of plates may be joined together by means of sulphur,
cement, or the like, or by simple juxtaposition and subsequent framing so as to
form one casement-like series or large plate.
Hitherto electrolytical apparatus have been devised without diaphragms, but if
desired the before described apparatus may be used in connection with diaphragms
and in that case the diaphragms may be arranged exactly in the same manner as
the electrode-plates.

page_text: Having now particularly described and ascertained the nature of the said
invention as communicated to me by my foreign correspondents, and in what
manner the same is to be performed, 1 declare that what I claim is ;-
1. Apparatus for the electrolysis of solution consisting of electrodes arranged
like a filter press and combining both poles substantially as described and
illustrated in Figures 1 and 2 of the accompanying drawings.
2. Apparatus for the electrolysis of solutions consisting of electrodes arranged
like a filter press and combining both poles and consisting of plates of metal or
other conducting material and insulating intermediate frames which are either
separate from or united with the electrodes and are composed of hard rubber
celluloid clay glass or other non-conducting material or of metal covered or coated
with non-conducting material and when pressed against the electrodes form a series
of closed divisions or chambers adapted to receive the solution to be treated only
the first and last plate of each series being connected each with one pole of the
source of electricity substantially as described.
3. In the apparatus characterized in Claim 1 the substitution for the electrodes
therein mentioned of compound electrodes composed of several small plates of
platinum carbon or other conducting material set in a frame made of non-conducting
material such as hard rubber, celluloid clay glass or the like or of metal covered
or coated with non-conducting material somewhat after the style of a window or
joined together by means of sulphur cement or the like or by simple juxtaposition
and subsequent framing substantially as described and illustrated in Figures 5, 6,
7, 8, 9 and 10 of the accompanying drawings.
4. In the apparatus characterized in Claim 2 the insertion of compound diaphragms
in the shape of plates composed in the same manner as the compound-electrodes
characterized in Claim 3 of smaller plates of clay of similar porous material and
arranged like the electrodes between the frames substantially as described.
Dated this 25th day of May 1893.
W. P. THOMPSON & BOULT,
Agents for the Applicants.