Improvements in and relating to the Electrodeposition of Copper and other Metals.
Year: 1897

page_text: Date of Application, 2nd Feb., 1897
Complete Specification Left, 1st Nov., 1897-Accepted, 4th Dec., 1897
[Communicated from abroad by EMILIEN DUMOULIN of 23 Boulevard de Strasbourg
Paris in the French Republic Electrical Engineer.]
Improvements in and relating to the Electrodeposition of Copper and
other Metals.
I, WILLIAM EDWIN HEYS of 70 Market Street Manchester in the county of
Lancaster, Chartered Patent Agent, do hereby declare the nature of this inven-
tion to be as follows:
In the Specification of Letters Patent No, 16360 dated the 31st. day of August
A.D. 1895, for an Invention communicated by my Foreign Correspondent, there
is described a system of Electrodeposition in which temporarily high parts of a
rotary cathode are treated so as to prevent temporary deposition thereon, with the
ultimate object of obtaining a homogeneous deposit. The present Invention relates
to certain Improvements which my Foreign Correspondent has made in his system
and which are hereinafter described.
According to the present Invention, the "Impregnators" which are employed
consist of animal membranes such as inrestines, bladders, and skins which have
had removed from them any adherent or excessive fatty or fleshy matters and
which have, preferably, been subjected for a fow hours to the action of a
lime
bath. When these membranes are microscopically examined, they are found to
be composed of a tangled mass of very minuto fibres and filaments chiefly com-
posed of albumen, gelatine and fibrine; and if they are plunged for sonic time
in water, at a temperature not exceeding 16° C., or 60° F., or thereabouts, these
fibres and filaments remain unaltered and their mass is found to be very soft and
yielding to the touch. These Impregnators are simply arranged, without contact,
upon the surface of the rotary cathode so that the least asperity roughness or
projection upon the cathode seizes some of the minutes fibres and filaments, with
which it becomes so covered or insulated as to prevent or retrd the further
deposition of metal thereon. In the meantime, the deposition continues in the
spaces between the asperities which shallow spaces thus gradually become higher
and higher, and the filaments are removed by the wash of the electrolyte and by
the impregnator itself. As the asperities diminish they will, of course, also take
up or be covered Ity fewer and fewer of the fibres until finally, with the dis-
appearance of the asperity, no more fibres are taken up and the last fibres are
washed off by the motion of the mandrel or removed by the impregnator itself.
My Correspondent has found that so long as the temperature of the bath remain
below about 16° C., the above described mechanical action alone takes place with
reference to the impregnator, but that if the temperature materially exceeds 16° C.,
a solvent action on the impregnator occurs which not only wastes the impregnator,
but also fouls the electrolyte. In order to avoid this result, he takes care that
this temperature is not exceeded in the electrolyte. This may be effected in
various ways, as for example, by keeping down the temperature of the room in

page_text: which the electrolysis takes place. He prefers however to arrange a system of
circulation and refrigeration in carrying out which the electrolyte is removed
from the vat and passed through a filter or filters and is then returned to tho
vat with or without temporary storage in intermediate cisterns or reservoirs.
During this circulation, the electrolyte may be caused to pass over pipes through
which a cold liquid is circulated or it may be otherwise cooled by known means.
In addition to or in substitution for such means for cooling, he prefers to blow
cold air through the liquid, especially in the case of copper solutions. This
insufflation of cold air is doubly useful since it not only cools the liquid but also
oxidises any organic matter, and precipitates any iron which may be contained
in the liquid.
To further shew the importance of low temperaturo as maintained according
to this Invention, it need only be observed that when the organic matters come
into solution, they commence to adhere to the cathode and become imprisoned
in it. Then, in the process of annealing, these matters are burnt and thus
genorate gases within the metal under enormnous pressures, which, fact makes
the metal short and brittle.
It has already been stated that any organic matters which may, notwithstanding
the precaution taken, enter into solution in the electrolyte, may be oxidised by
an insufflation of air, but this result may also be obtained but not so advan-
tageously, by introducing chemical oxidising agents such as Potassium Perman-
ganate. Suh means for oxidation has however the disadvantage of introducing
impurities into the bath.
When the cathodes are exposed to friction in any degive by impregnators,
brushes, rubbers and the like, it is usually found that the circumferential strength
and the longitudinal strength of the deposit are unequal. To obviate this result,
my Correspondent arranges that the path traced by any point of the impregnator
brush or rubber shall be as nearly as possible, at an angle of 45°. This may be
effected by giving to these articles a definite rectilinear reciprocation.
Whilst on the one hand it is desirable that the temperature of the bath should
not exceed 16° C., it is equally desirable on the other hand that its temperature
should not fall much below this. For this regulation of the temperature, there may
be employed heating devices of a suitable character, such as maintaining the
temperature of the room, causing the liquid to be in contact with heated pipes
or surfaces, blowing warm air instead of cold into it, and the like. Usually the a
appliances which are used for heating in cold weather may be employed for
cooling in hot weather.
Dated this first day of February A D 1807
COMPLETE SPECIFICATION.
Improvements in and relating to the Electrodeposition of Copper and
other Metals.
4
I, WILLIAM EDWIN HEYS of 70 Market Street, Manchester in the county of
Lancaster, Chartered Patent Agent, do hereby declare the nature of this inven-
tion, and in what manuer the same is to be performed, to be particularly described 4
and ascertained in and by the following statement.
In the Specification of Lettons Patent No. 16300 dated the 31st day of August
A.D. 1895, for an Invention communicated by my Foreign Correspondent, there
is described a system of electrodeposition in which temporarily high parts of a

page_text: rotary cathode are treated so as to prevent temporary deposition thereon, with
the ultimate object of obtaining a homogeneous deposit. The present Invention
relates to certain improvements which my Foreign Correspondent has made in
bis system und which are hereinafter described.
According to the present Invention, the "impregnators," by which term is
meant the substances or matters which come into contact with the rotary cathodes
and leave a deposit on the temporarily high parts, consist of animal membranes
such as intestines, bladders, and skins which have had removed from them any
adherent or excessive fatty, greasy or fleshy matters and which have preferably
been subjected for a few hours to the action of a lime bath, or of an equivalent
bath containing, for example, alum and common salt. Any other equivalent treat-
ment may be adopted with the essential object of ensuring that there does not
remain in or upon the impregnators any free greasy matters, or matters which
will become adhesive or sticky at temperatures of said below 16° C. (say 60° F),
or which at that temperature will readily come into solution in the electrolyte.
When these prepared membranes are examined under the microscope, they are
found to be composed of a tangled mass of very minute fibres and filaments which
are composed chiefly of albumen, gelatine and fibrine, and if these membranes
are plunged into water at a temperature not exceeding 16° C or 60° F, or there-
abouts for some time, the component fibres and filaments are found to be prac-
tically unaltered but the mass of the membranes will be found to be very soft and
yielding to the touch. The membraneous impregnators are simply arranged in
contact with the cathodes without pressure, so that the least asperity or roughness
on the cathode seizes upon some of the fibres and filaments with which the
asperities become covered or thatched so as to prevent or retard the further deposi-
tion of metal thereon. Thus, instantly upon a tendency to the production of a high
part on the cathode, this part temporarily by his means ceases to receive deposit,
or the progress of the deposit thereon is retarded. In the meantime, the deposi-
tion continues at the normal rate in the space or spaces between the temporarily
high or rough parts, and in a short time these parts reach the level of the
temporarily high parts. During the progress of the growth outwards of the normal
level and the comparative decrease in the height of the rough parts, the
fibres and filaments are bit by bit swept off by the motion of the cathode through
the eleclyte until uniformity of level is obtained and the last trace of the protec-
tive fibres has disappeared. Should the fibrous coating on an asperity be removed
before uniform level is reached, it will be evident that the asperity will re-protect
itself at its next contact with the impregnator. It will be evident also that by
this improvement, the asperities of the cathode, instead of being temporarily
coated with an adhesive insulator, as type is inked in the process of typography,
are simply conted or thatched temporarily with a filamentous covering which is
removed with the greatest ease by the motion of the cathode. There is conse-
quently less risk of organic matter being occluded in the deposited metal.
My Correspondent has found that so long as the temperature of the electrolytic
bath remains below about 16° C, the above described mechanical action alone
takes place with reference to the impregnator, but that if the temperature
materially exceeds 16° C, a solvent or disintegrating action on the impregnators
takes place, which not only wastes the impregnators but also fouls the electrolyte.
In order to avoid this result he adopts precautions to ensure that the temperature
of the electrolyte in the vats shall be maintained below the critical point and at
the same time, as far as may be required, to purify the elctrolyte by filtration,
by blowing air into it, by chemical action and other wise.
This part of the said Invention will be described with reference to the accom-
panying drawings in which —
Figure 1 represents a longitudinal sectional elevation: Figure 2, a plan and
Figure 3 a transverse sectional elevation of part of an installation, diagrama-
tically.

page_text: As shewn by the drawings the vats A are arranged in parallel series, but any
other convenient arrangement may be adopted at will.
In connection with each vat there is an overflow pipe h joined by a pipe h
to the main i, which discharges into the tank kat a level lower than that of the
vats. From this tank the liquid is pumped by the pump or elevator to the 5
tank mat a higher level. From this tank there may be an overflow pipe n
adapted to return any excess of liquid to the tank k. The liquid flows by gravity
from the tank m to the filter o, and thence to the reserve tank p. If however
the electrolyte does not require any further treatment, it can be returned to the
vats direct from the tank m, or from the filter o. It may also be returned direct 1
from the reserve tank p. In either case suitable connections are made as will
be obvious, with the return main pipe g. It is generally advantageous to provide
a second reserve tank pinto which the liquid can flow or overflow from the
tank P. From this tank the liquid is raised by the pump through the suction
pipe and delivery pipe to the tank m on the same level with the tank m.
Any overflow from the tank m is conveyed back to the tank through the over-
flow pipe The liquid returns from the tank m¹ through the pipes g', g, f'; fr
to longitudinal perforated pipes in the vats. The flow of the liquid is controlled
by valves at the necessary points. The incoming liquid displaces the liquid
already in the vats, which overflows as already described and completes the 2
circulation.
The cooling of the liquid, when necessary, may be achieved in various way of
which the following are mentioned only as examples. (a) By local cooling in the
vats by known means such as by circulating a cold liquid through pipes contained
therein (b) By blowing air into it at suitable points: (c) By causing it to flow
over or rest in contact with serpentina or other pipes in which a cold fluid is
circulated, on its way to or from, or in any of the tanks k, m, m', p, p².
When filtration is not required, the filter o may be cut out by a bye-pass, not
shown, between the pipes and the latter of which leads to the tank p.
For the purification of the electrolyte, so far as any organic matter which may
have come into it is concerned, either chemical treatment or aerial oxidation
may be employed according to the nature of the bath. In copper deposition
cupric oxide (CuO) may be added. In other cases potassium pormanganate or
other suitable oxidising agents may be employed. When aerial oxidation is
employed, it is best to blow air into the solution, as this not only oxidises the a
organic matter but also brings down any iron that may be contained in the
liquid. The insufflation of air may be effected in the tank m, and the cooling
in the tank or similarly. The matters rendered insoluble by the oxidation are
then removed by the filtor.
To shew the importance of low temperature as maintained according to this
invention, it need only be observed that when the organic matters come into
solution, they commence to adhere to the cathode and become imprisoned in it.
Then, in the process of annealing, these matters are burnt and thus generate
gases within the metal under enormous pressures, which fact makes the metul
short and brittle.
The oxidation by the injection of air or, in the case of copper by the addition
of cupric oxide, offers the advantage that no foreign matter is introduced which
might deteriorate the electrolyte.
Electric current may be supplied from the generating dynamo u and conductors
as indicated by Figure 2 or otherwise.
4
The cooling of the electrolyte may be effected by continuously withdrawing it
from the vats and returning it thereto after passing it through cooling tanks or
a cooling apparatus. A suitable cooling apparatus is sectionally illustrated by
Figure 4. It consists of a tank containing a serpentine pipe or coil w.
This
may be used in either of two ways, that is to say the electrolyte may be caused 5
to pass through the pipe immersed in a cooling liquid in the tank, or by passing
the electrolyte through the tank and a freezing or cooling fluid through the pipe."

page_text: Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed, as communicated to
me by my Foreign Correspondent, I declare that what I claim is:—
1. The hereinbefore described method of and means for obtaining a smooth
homogeneous electrodeposit of metal on a rotary cathode which consists in
employing animal membranes from which the, excess of greasy and flesh matters
have been removed which come into light contact with the cathode, substantially
us hereinbofore described.
2. The hereinbefore described method of and means for circulating and cooling
the electrolyte used in depositing copper and other metals, substantially as set
forth.
3. The hereinbefore described method of and means for circulating, cooling
and filtering the electrolyte used in the electrodeposition of copper and other
metals, substantially as set forth.
4. The hereinbefore described method of and means for circulating, oxidising.,
and filtering the electrolyte used in the electrodeposition of copper and other
metals substantially as set forth.
The hereinbefore described method for the purification of the electrolyte
used in the electrodeposition of copper and other metals, which consists of injecting
air therein, and afterwards cooling the electrolyte (if necessary): substantially
as set forth.
6. The use of impregnators coming into light contact with rotary cathodes in
electrodepositing vats for the purpose set forth such impregnators being composed
of animal membranes freed from excess of grease and from matters which are
or can become soluble or adhesive at or below about 16° C and consisting of
una..ered albumeu, fibrine and gelatine: substantially as set forth.
Dated this tuti dan
1007
Deted A..
1007
W. E HEYS & SON,
Agents for the Applicant.