Improvements in Diaphragms for Use in Electrolytical Apparatus.
Year: 1895

page_text: Date of Application, 17th May, 1895
Complete Specification Left, 28th May, 1895-Accepted, 6th July, 1895
PROVISIONAL SPECIFICATION.
Improvements in Diaphragms for Use in Electrolytical Apparatus.
I, ROGER COMBOUL, of 21 Rue Bergére, Paris, France, Gentleman, do hereby
declare the nature of this invention to be as follows:
In certain electro-chemical operations, and especially in the electrolysis of
soluble salts, the operations are often stopped or interfered with by the rapid
destruction of the diaphragms and cells or casings employed owing to these being
attacked by corrosive agents and particularly by oxygen, chlorine, or other
destructive substances present in or evolved from the electrolyte treated.
But
In order to obviate this drawback, there have been employed porous partitions
of material such as biscuit-baked porcelain, or even, sometimes, actual walls of
silicious bricks that are not attacked by the corrosive agents referred to.
these solid partitions possess the double inconvenience of occasioning a great
resistance, tb the detriment of the out-put, and of becoming encumbered with solid
matters that still further increase the resistance by gradually reducing the
porosity.
A thin sheet of material such as textile fabric, parchment, or parchment-like
paper would, on account of its small resistance and low cost, be a desirable material
to use as a diaphragm to separate the electrodes used in electrolysis, but for the
fact that such material is not usually in a state to resist the action of the corrosive
substances met with in electrolytical operations.
In certain cases, as for example in the electrolysis of chloride of sodium, it has
been attempted to entirely abolish these too rapidly destroyed partitions by using
the artifice of the differences of densities or of the special properties of mercury
and of amalgamated plates. But although these methods may have entered into
industrial practice, they present great inconveniences owing to the complexity of
the apparatus rendered necessary by them, the cost of repairing the same, and the
losses of various kinds that they involve.
It is therefore considered preferable to return to the use of permeable partitions,
which are more economical and easier to employ than the substitutes therefor above
referred to, and this invention has for object to provide means for safe-guarding
the existence of the membranes used in the construction of such diaphragms,
notwithstanding the presence of corrosive substances.
For this purpose I construct a diaphragm with two or more porous partitions
between which or each adjacent pair of which is held a layer of liquid, that may
be a solution of salt, the nature of which will not materially impede the electrolytic
operation. Whatever may be the nature of the porous partitions, it has been found
by comparative experiments that their duration is greatly prolonged by the
preservative action of the layer of liquid between them.
In general, the porous partition is composed of two membranes or sheets of
material such as cloth or other textile fabric, felt, and other porous sheet material
such as paper, parchment-like paper, (vegetable parchment) or wood, which are
consolidated and maintained in the desired form, by appropriate means, and between
which a layer of water, more or less charged with salts, is introduced. Such a
diaphragm is specially suitable for use in the electrolysis of chloride of sodium
and other chlorides in the wet way. Under the conditions explained, it is
remarkable to see how little the electrolytical action modifies the composition of the
liquid partition, which merely tends to become lower on account of a secondary
phenomenon. To obviate such tendency the liquid partition is maintained at a

page_text: constant level either mechanically or by means based on capillarity. This latter
result may be attained by juxtaposing two membranes or sheets of textile fabric
that are unequally porous and permeable, and between and in which the actions of
capillarity and of endosmosis maintain the required sheet or layer of liquid of
suitable composition to safe-guard the existence of the diaphragm. Under such
conditions it is found that the thin porous partitions or membranes are enabled to
well resist the action of destructive agents to which they are subjected.
Dated this 17th day of May 1895.
F. WISE HOWORTH,
46 Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
I, ROGER COMBOUL, of 21 Rue Bergére, Paris, France, Gentleman, 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 :-
In certain electro-chemical operations, and especially in the electrolysis of
soluble salts, the operations are often stopped or interfered with by the rapid
destruction of the diaphragms and cells or casings employed owing to these being
attacked by corrosive agents and particularly by oxygen, chlorine, or other
destructive substances present in or evolved from the electrolyte treated.
But
In order to obviate this drawback, there have been employed porous partitions
of material such as biscuit-baked porcelain, or even, sometimes, actual walls of
silicious bricks that are not attacked by the corrosive agents referred to.
these solid partitions possess the double inconvenience of occasioning a great
resistance, to the detriment of the out-put, and of becoming encumbered with
solid matters that still further increase the resistance by gradually reducing the
porosity.
A thin sheet of material such as textile fabric, parchment, or parchment-like
paper would, on account of its small resistance and low cost, be a desirable material
to use as a diaphragm to separate the electrodes used in electrolysis, but for the
fact that such material is not usually in a state to resist the action of the corrosive
substances met with in electrolytical operations.
In certain cases, as for example in the electrolysis of chloride of sodium, it has
been attempted to entirely abolish these too rapidly destroyed partitions by using
the artifice of the differences of densities or of the special properties of mercury
and of amalgamated plates. But although these methods may have entered into
industrial practice, they present great inconveniences owing to the complexity of the
apparatus rendered necessary by them, the cost of repairing the same, and the
losses of various kinds that they involve.
It is therefore considered preferable to return to the use of permeable partitions,
which are more economical and easier to employ than the substitutes therefor above
referred to, and this invention has for object to provide means for safe-guarding
the existence of the membranes used in the construction of such diaphragms,
notwithstanding the presence of corrosive substances.
For this purpose I construct a diaphragm with two or more porous partitions
between which or each adjacent pair of which is held a layer of liquid, that may
be a solution of salt, the nature of which will not materially impede the electrolytic
operation. Whatever may be the nature of the porous partitions, it has been
found by comparative experiments that their duration is greatly prolonged by the
perservative action of the layer of liquid between them.

page_text: In general, the porous partition is composed of two membranes or sheets of
material such as cloth or other textile fabric, felt, and other porous sheet material
such as paper, parchment-like paper, (vegetable parchment) or wood, which are con-
solidated and maintained in the desired form, by appropriate means, and between which
a layer of water, more or less charged with salts, is introduced. Such a diaphragm is
specially suitable for use in the electrolysis of chloride of sodium and other
chlorides in the wet way. Under the conditions explained, it is remarkable to see
how little the electrolytical action modifies the composition of the liquid partition,
which merely tends to become lower on account of a secondary phenomenon. To
obviate such tendency the liquid partition is maintained at a constant level either
mechanically or by means based on capillarity. This latter result may be attained
by juxtaposing two membranes or sheets of textile fabric that are unequally porous
and permeable, and between and in which the actions of capillarity and of endos-
mosis maintain the required sheet or layer of liquid of suitable composition to
safe-guard the existence of the diaphragm. Under such conditions it is found
that the thin porous partitions or membranes are enabled to well resist the action
of destructive agents to which they are subjected.
flaving 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 :-
1. In a diaphragm for electrical apparatus the use of a liquid partition arranged
between two or more partitions formed of permeable membranes or sheets of
material such as textile fabrics, felt, vegetable parchment, wood, and the like, for
the purpose of protecting such porous partitions against the action of corrosive
agents during electrolysis substantially as herein described.
2. In the electrolysis of chloride of sodium or other chlorides in the wet way,
the use of a diaphragm formed of two membranes, or sheets of material such as
vegetable parchment, or textile fabrics between which is constantly held a layer of
water which is more or less charged with salts and the presence of which acts to
greatly prolong the life of the said membranes or sheets in spite of the corrosive
actions of the chlorine and the soda produced by electrolysis, substantially as
herein described.
3. A diaphragm of the kind referred to in the preceding claims in which the inter-
posed layer of liquid is maintained practically constant in height by the combined
actions of capillarity and endosmosis, produced by the use of porous partitions of
unequal porosity and permeability, substantially as herein described.
Dated this 28th day of May 1895.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.