IMPROVEMENTS IN THE MANUFACTURE OF CAST HOLLOW CYLINDERS OF COPPER AND OTHER CASTINGS OF COPPER."
Year: 1879

page_text: LETTERS PATENT to Samuel Walker, of Birmingham, in the County of Warwick,
Manufacturer, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
CAST HOLLOW CYLINDERS OF COPPER AND OTHER CASTINGS OF COPPER."
PROVISIONAL SPECIFICATION left by the said Samuel Walker at the Office
of the Commissioners of Patents on the 2nd December 1879.
SAMUEL WALKER, of Birmingham, in the County of Warwick, Manufacturer.
"IMPROVEMENTS IN THE MANUFACTURE OF CAST HOLLOW CYLINDERS OF COPPER
AND OTHER CASTINGS OF COPPER."
My Invention has reference principally to the manufacture of the cast hollow
cylinders of copper from which copper tubes are made, but is also applicable to the
production of other castings of copper, such, for example, as copper rollers used for
printing fabrics.
I will describe my Invention in connection with a cast hollow cylinder of
copper.
In the ordinary method of casting hollow cylinders of copper the casting produced
is porous or unsound. In order to prevent porosity or unsoundness in the casting
I add to the melted copper, a short time before pouring it into the mould, crushed
or powdered cryolite, or an artificially prepared compound having a similar com-
position. In pouring the copper into the mould the fused cryolito is poured with
it. By the action of the said cryolite on the melted copper a sound casting, that is,
a casting free from the porosity of an ordinary copper casting, is produced. The
copper casting so obtained is however harder than is desirable for the manufacture
of tubes. In order to remedy this hardness I add to the melted copper, in addition
to the cryolite, acetate of lead, which gives the required ductility to the copper.
The mineral cryolite is a double fluoride of aluminium and sodium, and is an
article of commerce.
.
I find in practice that somewhat less than one part by weight of cryolite to one
hundred parts by weight of copper, and a quantity of acetate of lead equal to about
one third the quantity of cryolite, produce satisfactory results. The proportions of
the ingredients may however be varied.
After the copper has been melted I add the cryolite and acetate of lead. After
from ten minutes to a quarter of an hour I pour the melted copper, together with
the flux (cryolite and lead salt), into the mould.
By my Invention copper may be cast for a variety of purposes to which copper
cast in the ordinary way cannot be applied.
Where only freedom from porosity is required in the casting the cryolite alone
may be used. Where, in addition to freedom from porosity, ductility is required,
acetate of lead must be used in addition to the cryolite.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Samuel Walker in the Great Seal Patent Office on the 19th May
1880.
88
SAMUEL WALKER, of Birmingham, in the County of Warwick, Manufacturer.
IMPROVEMENTS IN THE MANUFACTURE OF CAST HOLLOW CYLINDERS OF COPPER
AND OTHER CASTINGS OF COPPER."
My Invention has reference principally to the manufacture of the cast hollow
cylinders of copper from which copper tubes are made, but is also applicable to the
production of other castings of copper, such, for example, as copper rollers used for
printing fabrics.
I will describe my Invention in connection with a cast hollow cylinder of
copper.
In the ordinary method of casting hollow cylinders of copper the casting produced
is porous or unsound. In order to prevent porosity or unsoundness in the casting
I add to the melted copper, a short time before pouring it into the mould, cryolite,
preferably crushed or powdered, or any compound natural or artificial having a
similar composition.
In pouring the copper into the mould the fused cryolite may be poured with it.
This however is not necessary, and in cases where it is for any reason inconvenient
or undesirable to pour the fused cryolite into the mould it may be retained in the
melting pot, and the fused copper only be poured into the mould. By the action
of the said cryolite on the melted copper a sound casting, that is, a casting free from
the porosity of an ordinary copper casting, is produced. The copper casting so
obtained is however harder or less ductile than is desirable for the manufacture of
tubes. In order to correct this hardness or want of ductility I add to the melted
copper, in addition to the cryolite, acetate of lead, which gives the required ductility
to the copper.
The mineral cryolite is a double fluoride of aluminium and sodium, and is an
article of commerce.
I find in practice that somewhat less than one part by weight of cryolite to one
hundred parts by weight of copper, and a quantity of acetate of lead equal to about
one third the quantity of cryolite produce satisfactory results; that is, to every one
hundred pounds of copper I add about one pound of cryolite and one quarter of a
pound of acetate of lead. To these materials about one pound of borax may be
added. The proportions of the ingredients may however be varied.
After the copper has been melted I add the mixture of cryolite and acetate of
lead either with or without borax. After from ten minutes to a quarter of an hour,
or soon after the mixture of cryolite, acetate of lead, and borax has thoroughly
melted, I pour the melted copper either with or without the flux (cryolite and lead
salt with or without borax) into the mould.
Copper castings made according to my Invention may be used for a variety of
purposes to which copper cast in the ordinary way cannot be applied. Where only
freedom from porosity is required in the casting the cryolite alone may be used.
Where, in addition to freedom from porosity, ductility is required, acctate of lead
may be used in addition to the cryolite.
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 of
"Improvements in the Manufacture of Cast Hollow Cylinders of Copper and other
Castings of Copper,"-
First. Preventing porosity or unsoundness in cast hollow cylinders of copper and
other castings of copper by adding to the melted copper, before pouring it into the

page_text: mould, cryolite or other compound natural or artificial of similar composition, either
alone or with the addition of borax, substantially as herein before described.
Secondly. Preventing porosity or unsoundness in cast hollow cylinders of copper
and other castings of copper, and at the same time giving ductility to the said
cast hollow cylinders and other castings of copper by adding to the melted copper,
before pouring it into the mould, cryolite or other compound natural or artificial
having a similar composition, together with acetate of lead either with or without
the addition of borax, substantially as herein before described.
In witness whereof, I, the said Samuel Walker, have hereunto set my hand
and seal, this First day of April, in the year of our Lord One thousand eight
hundred and eighty.
Witness,
RICHARD SKERRETT,
Clerk to George Shaw,
Birmingham.
SAMUEL WALKER. (L.S.)