IMPROVEMENTS IN THE PRODUCTION OF CAST HOLLOW COPPER CYLINDERS AND OTHER CASTINGS IN COPPER
Year: 1877

page_text: LETTERS PATENT to William Edward Everitt, of Birmingham, in the County
of Warwick, Manufacturer, for the Invention of "IMPROVEMENTS IN THE
PRODUCTION OF CAST HOLLOW COPPER CYLINDERS AND OTHER CASTINGS IN
COPPER"
Sealed the 6th July 1877, and dated the 5th May 1877.
PROVISIONAL SPECIFICATION left by the said William Edward Everitt at
the Office of the Commissioners of Patents on the 5th May 1877.
"
WILLIAM EDWARD EVERITT, of Birmingham, in the County of Warwick, Manu-
facturer. IMPROVEMENTS IN THE PRODUCTION OF CAST HOLLOW COPPER
CYLINDERS AND OTHER CASTINGS IN COPPER."
In the production of castings in copper, and especially in the production of cast
hollow copper cylinders and other cored articles great difficulty is experienced in
obtaining a thoroughly sound casting, the metal being generally porous or unsound
at and near the surface, and especially so in the case of surfaces formed in contact
with the core.
My Invention has for its object to remedy this defect, and consists of the improve-
ments herein-after described, whereby sound castings in copper can be produced
with great certainty.
My Invention is especially applicable to the production of cast hollow cylinders
of copper for the manufacture of seamless copper tubes.
In the production of cast hollow cylinders of copper or other castings in copper,
according to my Invention, I proceed in the ordinary way in the preparation of the
mould and in the melting of the copper, but shortly before removing the melted
copper from the furnace, or after having removed it therefrom, I introduce into the
melted metal a quantity of cyanide of potassium. The proportion of the cyanide
of potassium to the melted copper does not require to be adjusted with nicety, but
I have found in practice that twenty-four ounces of cyanide of potassium to one
hundred pounds of copper gives excellent results. The cyanide of potassium is
stirred for a short time with the melted copper, when the latter is ready to be poured
into the mould.
The casting produced is free from the sponginess or unsoundness common to copper

page_text: Although I prefer cyanide of potassium yet other analogous cyanide, such for
example as the cyanide of sodium, may be employed; or compounds which in contact
with melted copper yield a fusible cyanide may be employed, such for example, as
dried ferroprussiate of potassium.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Edward Everitt in the Great Seal Patent Office on the 24th
October 1877.
WILLIAM EDWARD EVERITT, of Birmingham, in the County of Warwick,
Manufacturer. "IMPROVEMENTS IN THE PRODUCTION OF CAST HOLLOW COPPER
CYLINDERS AND OTHER CASTINGS IN COPPER."
In the production of castings in copper, and especially in the production of cast
hollow copper cylinders and other cored articles, great difficulty is experienced in
obtaining a thoroughly sound casting, the metal being generally porous or unsound
at and near the surface, and especially so in the case of surfaces formed in contact
with the core.
My Invention has for its object to remedy this defect, and consists of the improve-
ments herein-after described, whereby sound castings in copper can be produced with
great certainty.
My Invention is especially applicable to the production of cast hollow cy
copper for the manufacture of seamless copper tubes.
lind
ers of
In the production of cast hollow cylinders of copper or other castings in copper,
according to my Invention, I proceed in the ordinary way in the preparation of the
mould and in the melting of the copper, but shortly before removing the melted
copper from the furnace, or after having removed it therefrom, I introduce into the
melted metal a quantity of cyanide of potassium. The proportion of the cyanide of
potassium to the melted copper does not require to be adjusted with nicety, but I
have found in practice that the proportion of twenty-four ounces of cyanide of
potassium to one hundred pounds of copper gives excellent results. The cyanide
of potassium is stirred for a short time with the melted copper when the latter is
ready to be poured into the mould.
The casting produced is free from the sponginess or unsoundness common to
copper castings.
Although I prefer cyanide of potassium, yet other analogous fusible cyanide, such
for example as the cyanide of sodium, may be employed; or compounds which in
contact with melted copper yield a fusible cyanide may be employed, such for
example, as dried ferroprussiate of potassium.
The cyanide of potassium which I have found to answer well in carrying my
Invention into effect is the ordinary cyanide of potassium of commerce, such as is
usually employed in electro-plating. This cyanide of potassium contains carbonate
of potash and cyanide of potash, impurities resulting from the method of its manu-
facture, but they do not affect its value for ordinary purposes, and the said commercial
cyanide of potassium practically answers as well in carrying my Invention into
effect as purer and more costly cyanide of potassium.
When I employ ferroprussiate of potash, otherwise called yellow prussiate of
potash, I reduce it to fine powder, and thoroughly dry it by heating it as long as
vapour of water is driven off. When it has been thus deprived of the whole of the
water contained in it in its commercial crystallized state, it is fit for use. When it
is brought into contact with the melted copper it is decomposed by the heat, and
cyanide of potassium is produced among other products of its decomposition.
When ferroprussiate of potash is employed in place of cyanide of potassium twice
as much of the said ferroprussiate of potash is required to replace a given quantity
of cyanide of potassium.

page_text: I wish it to be distinctly understood that although the various improvements I
have described are efficient in practice, and differ but little in the result produced,
yet I prefer, as being most efficient in result and simplest in practice, the improve-
ment herein first described, namely, the employment in the manner described of
commercial cyanide of potassium in the production of castings in copper.
Although my Invention is specially applicable to the casting of hollow copper
cylinders for the manufacture of tubes and rollers and other hollow and cored
castings in copper, yet it is also applicable to the casting of solid masses of
copper.
The spongy or porous character of copper castings, which it is the object of my
Invention to prevent, is common more or less to all the surfaces which have been
formed in contact with the mould or core, those surfaces cast in contact with the
core being generally the worst. By my Invention the spongy or porous character
referred to is wholly prevented, both on the surfaces cast in contact with the core,
as well as those cast in contact with the mould; but as the spongy or porous
character is generally worst in the case of articles cast in core moulds my Invention
is of especial value in the casting of such articles.
Having now described the nature of my Invention, and the manner in which the
same is to be performed, I wish it to be understood that I claim as my Invention,
the improvements in the production of cast hollow copper cylinders and other
castings in copper herein-before described, that is to say, adding cyanide of potassium
to the molten copper which is about to be cast, and immediately before pouring the
said molten copper into the mould, or adding to the said molten copper immediately
before casting the same other fusible cyanides or compounds, which by contact with
the molten copper yield a fusible cyanide, substantially as described.
In witness whereof, I, the said William Edward Everitt, have hereunto set
my hand and seal, this Twenty-third day of October, in the year of our
Lord One thousand eight hundred and seventy-seven.
Witness,
GEORGE SHAW.
WILLIAM EDWARD EVERITT. (L.B.)