Improvements in the Production of Copper Tubes by Electrolysis.
Year: 1891

page_text: Date of Application, 8th June, 1891
Complete Specification Left, 8th Apr., 1892-Accepted, 14th May, 1892
PROVISIONAL SPECIFICATION.
Improvements in the Production of Copper Tubes by Electrolysis.
ALEXANDER WATT, 81, Fernlea Road, Balham, Surrey, Electro-chemist do
hereby declare the nature of this invention to be as follows:-
-
This invention relates to an improved method of obtaining electrolytic deposits
of copper, in the form of tubes, by means of which the metal is obtained in a more
compact and coherent condition than is obtainable by the methods hitherto
adopted.
In carrying out this invention, for the manufacture of copper tubes, the mandrel
or core upon which the copper deposit is to be obtained, is, by preference, composed
of a metal or alloy which is fusible at a moderately low temperature, such as type
metal, Britannia metal, stereotype metal, or any similar alloy, in order that the
core or mandrel may be readily separated from the copper deposit, or tube, by
simply heating the latter until the alloy melts, and the melted metal may be allowed
to run into a previously prepared mould to form another similar core or mandrel
for use in the same way. These mandrels may be cast in the form of hollow
cylinders of suitable thickness according to the length of the copper tube to be
produced, and are mounted on an axis connected by suitable gearing for giving the
mandrel a horizontal rotary motion, as will be well understood. The ends of
the cylindrical core or mandrel are fitted with discs of wood, Fig. I. (see drawing),
ebonite, or other suitable insulating material, and through these discs the axis
passes. In order to keep the discs securely in their proper position, several
equidistant grooves may be formed in the ends a a of the hollow mandrel Fig. II.,
and corresponding projections bb left on the wooden or other discs to fit into these
grooves. The axis may be of brass or hard wood, and may be secured to the
discs aforesaid by means of a pin at each end c. The mandrel is first coated with
a film of copper or brass in an ordinary cyanide solution of the metal or alloy,.and
after being well rinsed is next placed in the sulphate of copper bath in which the
tube is to be produced, and in which is suspended, or otherwise disposed, one or more
copper anodes, in connection with the positive pole of a dynamo-electric machine
or other source of electricity. The mandrel, which forms the cathode, or negative
electrode is put in connection with the negative pole of the source of electricity.
When it is desired to deposit the copper from the sulphate solution for the
purpose of extracting the copper therefrom, as when the sulphate of copper is
obtained by dissolving out the oxide of copper from calcined copper ores, as in the
author's Patent dated January 10th 1891, No. 516, anodes of carbon or sheet lead may
be used, and copper tubes may thus be formed without employing copper anodes,
provided the solution of sulphate be strengthened continuously by the addition of
concentrated copper liquor to the sulphate solution as it becomes deprived of its
metal during the electrolysis.
In order to improve the character of the copper deposit during its formation upon
the surface of the mandrel, an essential part of this invention consists in subjecting
the deposit, while deposition is progressing, to the action of a hard brush, or a
rubber, which, while the mandrel. is revolving presses against its surface, at any
desired part, but preferably upon the upper part of the revolving cylinder, causing
the deposit which would otherwise assume a dull, crystalline character-to become
moderately brightened, the brush or rubber producing a similar effect to the well-
known operation of "scratch-brushing" adopted by silver platers; that is to say,
the minute crystals of the deposited copper become laid down, so to speak, and are
thus prevented from acquiring definite crystalline form, which would be the case if
no brush or rubber were applied. The effect of the continuous brushing or rubbing

page_text: of the deposit during the deposition of the metal is to produce a smooth, uniform,
compact deposit of the metal throughout its entire substance, by which it is rendered
perfectly dense without becoming in any way foliated or stratified. The brush or
rubber used for the purpose before mentioned may extend the entire length of the
mandrel, or a smaller brush or rubber may be adjusted by suitable mechanical
arrangement by which it may be made to travel from end to end of the mandrel
and back again, as will be well understood.
Another important result of the brushing or rubbing action upon the deposited
copper is that, by allowing the mandrel to run at a tolerably high speed, a strong
electric current may be employed, and in this way considerable quantities of metal
may be deposited per hour without its assuming the crystalline form. Thus very
thick deposits of copper may be obtained in a comparatively short time.
The brushes to be employed for the purposes of this invention may be made from
strong bristles, cocoa-nut fibre, whalebone, or any suitable material, and the rubbers
may consist of pads of leather, cork, felt, india-rubber, or any substance capable
of brightening, by moderate pressure, the naturally dull surface of electro-deposited
copper.
In the manufacture of copper tubes by this invention, the mandrels or cores may
be made of iron instead of the fusible metal or alloy, if preferred, in which case it
will be necessary to give the mandrel a preliminary coating of brass or copper in
an alkaline bath, to protect it from the action of the sulphate of copper solution in
which the main deposit is afterwards effected.
Dated this 8th day of June 1891
ALEXANDER WATT.
COMPLETE SPECIFICATION.
Improvements in the Production of Copper Tubes by Electrolysis.
1 MARTHA WATT, Widow and Administratrix of the late Alexander Watt,
81 Fernlea Road, Balham, Surrey, Electro-chemist, 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:-
This invention relates to an improved method of obtaining electrolytic deposits
of copper in the form of tubes, by means of which a more compact and coherent
deposit of the metal is secured, than by the methods hitherto adopted.
In carrying out this invention for the manufacture of copper tubes, the copper
deposit takes place on a suitable mandrel or core, to which rotary motion is given
in any convenient manner, while immersed in the electrolytic bath.
The mandrel is first coated with a film of copper or brass in an ordinary cyanide
solution of the metal or alloy, and after being well rinsed, is next placed in a
sulphate of copper bath in which the tube is to be produced, and in which is
suspended, or otherwise disposed, one or more copper anodes in connection with the
positive pole of a dynamo-electric machine or other source of electricity. The
mandrel, which forms the cathode or negative electrode, is put in connection with
the negative pole of the source of electricity.
When it is desired to deposit the copper from the sulphate solution, for the
purpose of extracting the copper therefrom, as when the sulphate of copper is
obtained by dissolving out the oxide of copper from calcined copper ores, anodes
of carbon or sheet lead may be used, and copper tubes may thus be formed without
employing copper anodes, provided the solution of sulphate be strengthened con-
tinuously by the addition of concentrated copper liquor to the sulphate solution, as it.
becomes deprived of its metal during the electrolysis.
•
In order to produce a homogeneous deposit on the mandrel, the deposit is subjected
(while deposition on the immersed mandrel is progressing) to the friction of a fixed
or travelling brush or rubber (in contrast to the burnishers hitherto employed),
winch, while the mandrel is revolving, presses against its surface at any desired part,

page_text: but preferably upon the upper part of the revolving cylinder, causing the deposit
which would naturally assume a dull crystalline character, or, if burnished, receive
a metallic lustre, to become compacted or consolidated, the minute crystals of the
deposited copper being thereby laid down," and prevented from acquiring definite
crystalline form, which would be the case if no brush or rubber were applied. The
effect of the continuous brushing or rubbing of the copper tube during the deposition
of the metal, is to produce a uniform compact deposit throughout the thickness of
the tube, thus avoiding the defects hitherto realised in the production of tubes by
electrolysis, there being no tendency for the deposit to become laminated, foliated,
or stratified.
The brush or rubber used for the purpose before mentioned, may extend the
entire length of the mandrel, or a smaller brush or rubber may, by suitable
mechanical arrangements, be made to travel from end to end of the mandrel and
back again, as will be well understood.
An important result obtained from the use of brushes, or yielding rubbing
surfaces, upon the deposited copper, is that the mandrel may be run at a tolerably
high speed, thereby permitting of the employment of a strong electric current, in
consequence of which a rapid deposit of the metal takes place, without assuming
the crystalline form. Thus, very thick deposits of copper may be obtained in a
comparatively short time.
The brushes to be employed for the purposes of this invention, may be made from
strong bristles, cocoa-nut fibre, or whalebone, and the rubbers may consist of pads
of leather, cork, felt, or india rubber, which friction surfaces will, by the aid of
moderate pressure, produce the desired result.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, it may be here remarked,
that it is not intended, in this Specification, to claim the use of a burnishing tool
of agate, glass, or other hard substance, acting under considerable pressure on the
copper deposit in the bath, while the deposition is taking place, as the effect of
the action of such a tool is to foliate or stratify the deposit, a result which it is the
sole object of the present invention to overcome, but what is claimed is :-
In the manufacture of copper tubes by electrolysis, the use of friction produced
by the application of yielding surfaces, such as brushes and pads, as above set forth,
the same being placed in the electrolytic bath, and acting on the deposited copper,
as and for the purpose set forth.
Dated this 8th day of April 1892.
NEWTON & SON,
Agents for the Applicant.