Improvements in and connected with Tanks for the Electrical Decomposition of Chloride of Sodium or Potassium in Solution.
Year: 1893

page_text: Date of Application, 30th June, 1893
Complete Specification Left, 30th Mar., 1894-Accepted, 5th May, 1894 '
PROVISIONAL SPECIFICATION.
Improvements in and connected with Tanks for the Electrical
Decomposition of Chloride of Sodium or Potassium in Solution.
I JAMES CHARLES RICHARDSON of 23 Claremont Square, London, N.,
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
:
The present invention relates to that class of electrical decomposing apparatus
wherein there is no diaphragm between the electrodes, to prevent re-combination
of the products of decomposition, the re-combination in such apparatus being
prevented by the employment of a substance which acts chemically to absorb and
remove the cause of such re-combination, viz., the hydrogen gas which forms at the
cathode or negative electrode.
In working apparatus of this kind on a large scale in the electrolysis of solutions
of chloride of sodium or potassium, there is found a slight tendency to re-combinė
on the part of the products of decomposition from another cause, that is to say, the
negative electrode is below, and the positive, or anode, is above. Around the
cathode forms the caustic alkali, which stratifies at a certain level, approaching
sometimes to near the bottom of the anodes. Although the disturbance of the
solution by the evolution of hydrogen gas at the cathode does not take place,
nevertheless a slight disturbance does take place, by reason of the chlorine gas
formed round and about the anode, and struggling to get to the surface of the
solution. This disturbance, together with some pressure incidental to the formation
and collection of the chlorine gas, is sufficient to bring about an appreciable amount
of mixing and re-combination between the products of decomposition collected
around and near their respective electrodes.
To prevent re-combination, and obviate the loss thereby accrning, I now propose
to arrange horizontally between the electrodes, a screen, preferably of slate or glass
strips or other material uninfluenced by the action of the decomposition. These
strips are supported on ledges in the tank, and may be placed so as to overlap one
another, like the slats of a Venetian blind, with spaces, however, between them, so
as not to obstruct the passage of the current between the electrodes. This screen,
which may be varied in form to suit different circumstances, will be quite sufficient
to prevent any downward pressure of the chlorine, or other source of disturbance
above alluded to, which is liable to bring the products of decomposition into too
close proximity in the tank.
Dated this 29th day of June 1893.
NEWTON & SON,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and connected with Tanks for the Electrical
Decomposition of Chloride of Sodium or Potassium in Solution.
I JAMES CHARLES RICHARDSON of 23 Claremont Square, London, N.,
0 Electrical Engineer, 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 present invention relates to that class of electrical decomposing apparatus

page_text: wherein there is no diaphragm between the electrodes, to prevent recombination
of the products of decomposition, the recombination in such apparatus being
prevented by the employment of a substance which acts chemically to absorb and
remove the cause of such recombination, viz. :-the hydrogen gas which forms at the
cathode or negative electrode.
In working apparatus of this kind on a large scale, in the electrolysis of solutions
of chloride of sodium or potassium, there is found a slight tendency to recombine,
on the part of the products of decomposition from another cause, which I am
about to explain. The negative electrode is below, and the positive, or anode, is
above, and around the cathode is formed the caustic alkali which stratifies at a
certain level, approaching sometimes to near the bottom of the anodes. Although
the disturbance of the solution by the evolution of hydrogen gas at the cathode
does not take place, nevertheless a slight disturbance does take place, by reason of
the chlorine gas formed round and about the anode, and struggling to get to the
surface of the solution, and causing sometimes pressure in a downward direction.
This disturbance, together with the pressure incidental to the formation and
collection of the chlorine gas, is sufficient to bring about an appreciable amount of
mixing and recombination between the products of decomposition collected around
and near their respective electrodes.
To prevent recombination, and obviate the loss thereby accruing, I now propose
to arrange horizontally between the electrodes, a screen, preferably of slate, or
glass strips, or other material uninfluenced by the action of the decomposition. These
strips are supported on ledges in the tank, and may be placed so as to overlap one
another, like the slats of a Venetian blind, with spaces, however, between them,
so as not to obstruct the passage of the current between the electrodes. This
screen, which may be varied in form to suit different circumstances, will be quite
sufficient to prevent any downward pressure of the chlorine, or other source of
disturbance above alluded to, which is liable to bring the products of decomposition
into too close proximity in the tank.
In the accompanying drawing I have shown in sectional side view, at Fig. 1, just
so much of an electrolytic tank as will serve to illustrate my invention. Fig. 2
shews a portion of a tank fitted with a modification of my invention.
a-are the positive electrodes, or anodes, suspended from the cover of the tank
which contains the solution to be electrolysed. care the cathodes, which may
consist of metallic trays containing the substance which acts chemically to absorb
the hydrogen as it is formed. These trays, which are lowered into the tank through
the uncovered portion shown to the left of Fig. 1, rest upon conducting ledges
extending longitudinally of the tank on either side.
B is a screen, which may be of lattice or other form, arranged horizontally
immediately beneath the anodes.
In Fig. 1, the horizontal screen is formed of slats of slate or glass, or 'some
other material not influenced by the chemical action' of the "electrolysis, supported
on ledges in the tank. The slats 6 are laid so as to overlap slightly at their edges,
and are held sufficiently apart by small blocks of paraffined wood or slate inserted
between them at their ends.
In Fig. 2, the screen takes the form of separate V-shaped troughs b, supported
beneath the anodes. These troughs serve not 'only to prevent the downward
pressure of gas formed at the anodes, but also to catch particles of the material of
which the anodes are composed, should any become detached during the progress
of the electrolysis.
The form of the horizontal screen may obviously be varied greatly without
departing from the general arrangement which I have laid down in the foregoing
remarks, the point of the invention being, shortly, to place a mechanical obstruction
between the electrodes, which will serve to prevent a disturbancet of the solution
by a downward pressure of gas from above, without in any way impeding the
passage of the current.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what mauner the same is to be performed, I declare that what I
claim is :-
In electrical decomposing apparatus of the kind hereinbefore referred to, the
employment of a horizontal screen of lattice, or equivalent open form, arranged
between the electrodes, as and for the purpose above set forth.
Dated this 27th day of March 1894.
NEWTON & SON,
Agents for the Applicant.