IMPROVEMENTS IN CASTING ARTICLES IN COPPER, BRONZE, BRASS, YELLOW METAL, AND OTHER ALLOYS OF COPPER, AND IN THE MOULDS AND APPLIANCES USED FOR THE PURPOSE, PARTLY APPLICABLE TO CASTING ARTICLES IN STEEL
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Perceval Moses Parsons at the Office
of the Commissioners of Patents on the 21st July 1880.
PERCEVAL MOSES PARSONS, of Melbourne House, Blackheath, in the County of
Kent, Civil Engineer. "IMPROVEMENTS IN CASTING ARTICLES IN COPPER,
BRONZE, BRASS, YELLOW METAL, AND OTHER ALLOYS OF COPPER, AND IN THE
MOULDS AND APPLIANCES USED FOR THE PURPOSE, PARTLY APPLICABLE TO
CASTING ARTICLES IN STEEL."
The object of my improvements is to obtain castings of greater strength and
soundness than can be produced by the usual methods of casting in open moulds,
and consist in making the moulds of suitable forms and parts, and applying pressure
to the metal in the mould while in a fluid or soft state by forcing a plunger into.
the mouth of the mould by hydraulic or other mechanical power.
In order to obtain sufficient strength to sustain the pressure applied, I make the
moulds of strong cast iron, wrought iron, or steel.
.
For casting plain ingots I make the mould by preference cylindrical externally,
and internally slightly conical or taper, leaving a hole at the bottom of less diameter
than the inner diameter of the mould, which hole is closed by a plug. This hole is
for the purpose of introducing a drift or plunger, by which the ingot after it is cast
is forced out of the mould along with the plug.
For casting articles which have a projection on them, such as a bolt with a head
or a spindle with a collar, I make the upper part of the mould above the projection
with a lining in two or more pieces divided longitudinally. The part of the
imould which receives these lining pieces is bored out slightly conical, and the lining
pieces being carefully faced and fitted together are turned on the outside to fit it,
and are bored out or made internally to the required form of the casting. A plug
is provided at the bottom of the mould, as before described, & when the casting is
made both it, the plug, & the lining pieces are driven out together.
For casting plates or slabs I make the mould in two halves, the interior being of
the form required, the outside being provided with strengthening flanges, the edges
of which are turned to fit into a strong casing bored out slightly conical, or instead
of one casing several rings may be driven on to the mould to hold it together and
sustain the pressure.
For casting tubes or tube ingots the interior of the mould is made slightly

page_text: conical, and the plug at the bottom has a mandrell attached to it which stands up in
the centre of the mould to form the core.
The object in making the interior of the moulds conical or taper is to allow of the
ingot, after it is cast, being driven out of the mould with facility, and the amount of
taper need not be more than sufficient to effect this object. In general a taper of about
1 in 50 in the diameter will be sufficient, and even less than this, down to nothing,
when-the-mould-becomes-very-short-in-proportion-to-its-diameter-and-the-surface-
is true and smooth; but if required to produce ingots of considerable length
perfectly cylindrical or parallel, the lining pieces before described may be employed
for casting plain ingots as well as such as have projections on them.
In making castings in all the moulds hereinbefore described, the moulds having
their parts properly fitted together, are placed under a suitable' hydraulic or
other press capable of exerting a pressure of, several tons on each square inch
area of the plunger, and the metal being poured into the mould, the plunger which
is made to fit the mouth of the mould is forced in while the metal is in a fluid or
soft state. The plunger to be used for casting tubes has a hole bored up it a
sufficient distance for the mandrell to pass into as the plunger descends into the
mould.
In casting some of the copper alloys, particularly those which contain a large
proportion of zinc, such as brass & yellow metal, the surface of the fused metal
becomes rapidly oxydised and a quantity of dross accumulates, which it is impor-
tant to prevent getting into the mould. For this purpose I make the crucibles
used in casting the herein before mentioned alloys with a lip, provided with an
aperture through which the clean metal passes into the mould, while the lip
intercepts.the dross floating on its surface. In new crucibles this lip may be made
with and form part of the crucible, but for existing ones it may be made of sheet
iron, held in its place by a clip or other fastening.
The construction of mould hereinbefore described for casting articles which
have projections on them is applicable to the casting of similar articles in steel.