IMPROVEMENTS IN APPARATUS TO BE EMPLOYED WHEN CASTING METALS OR ALLOYS UNDER PRESSURE
Year: 1876

page_text: LETTERS PATENT to Benjamin Joseph Barnard Mills, of the Firm of Harris and
Mills, of 23, Southampton Buildings, in the County of Middlesex, Patent
Agent, for the Invention of "IMPROVEMENTS IN APPARATUS TO BE EMPLOYED
WHEN CASTING METALS OR ALLOYS UNDER PRESSURE." A communication from
abroad by Pierro Ludovic Van den Berghie, of Paris, in the Republic of France.
PROVISIONAL SPECIFICATION left by the said Benjamin Joseph Barnard
Mills at the Office of the Commissioners of Patents on the 3rd March 1876.
BENJAMIN JOSEPH BARNARD MILLS, of the Firm of Harris and Mills, of 23,
Southampton Buildings, in the County of Middlesex, Patent Agent. 'IMPROVE
MENTS IN APPARATUS TO BE EMPLOYED WHEN CASTING METALS OR ALLOYS UNDER
PRESSURE." A communication from abroad by Pierre Ludovic Van den Berghe, of
Paris, in the Republic of France.
The Invention has for its object the casting metals or alloys under pressure in
general accordance with the methods patented by B. J. B. Mills, on the 11th day of
May 1869, No. 1443, and by James Mackintire, on the 31st day of December 1873,
No. 4287, and on the 30th day of December 1874, No. 4469, substituting however
for the cylinder and solid piston as therein described arrangements by which a fluid
piston, that is to say, the pressure given by or transmitted through a column of a
fusible metal, such as lead or any suitable alloy thereof shall force the metal intended
to be made into castings under pressure into mould or moulds, and shall give the
requisite pressure to cause the same to fill the moulds with exactness, and so
produce that sharpness of contour which is the main object of this method of
casting.
In carrying the Invention into effect the hydrostatic pressure of a column of
liquid lead of sufficient height, may be brought to press up the fused bronze or
other metal or alloy, and force it into the mould or the hydrostatic pressure of the
liquid lead upon the fused bronze, or other metal or alloy is produced by forcing a
cylindrical plunger into a close vessel containing the liquid lead in lieu of that
produced directly by a head or column of melted lead or the requisite pressure, to
force the melted bronze or other metal or alloy into the mould is produced by com-

page_text: pressed air, acting upon the surface of the liquid lead, and through that upon the
melted bronze or other metal or alloy.
The apparatus for the first of these methods is arranged somewhat as follows:-
A cylinder of cast iron is employed with flanges at its top and bottom ends, and at
the bottom a flange or fillet projecting inwards. This cylinder is lined with loam
which is dried or baked within the cylinder, and which must be cylindrical or
uniform in internal diameter when dried, such result being secured, either by
pressing the still plastic loam lining in the cylinder upon a core, afterwards to be
withdrawn, or by "spinning," or by boring the interior surface of the dried loam
by turning in a lathe according to methods well known to moulders. The bottom
or lower end of this cylinder is closed by a thin circular plate, which may be of
bronze, copper, or sheet iron, or other suitable material, but iron is preferred. This
plate whose diameter must be slightly less than that of the finished loam lining of
the cylinder, and the edge of which must be rounded, rests all round near its edge
upon the internal flange, projecting inwards, already described.
•
The lining of the cylinder composed of a suitable mixture of fine clay and sand,
with or without a mixture of fibrous matter, and well known to founders as "loam,"
being completed and baked or dried, is to be given one or more coats of that com-
position of clay, and pulverized coal, and water, well known to loam moulders as
"black wash" and the circular plate having been previously covered with one or
more coats of the same, which have been dried or baked upon it, is to be dropped
into its place upon the internal fillet, while the "black wash" upon that is still
wet, so that the plate may be rendered stanch to fluid metal at its junction with
the cylinder lining and the fillet. The lined cylinder and plate with their coatings
are now to be thoroughly dried together in the stove. The surfaces of the flanges at
the top and bottom of the cylinder being faced in the lathe, the lower flange is
placed upon a correspondingly faced recess provided in the cast-iron base, so that
there is a hollow space then enclosed beneath the sheet-iron or other plate, which
closes the bottom of the loam lined cylinder.
is
At one side of the base there is a pipe provided with an inlet cock, constructed
after the manner herein to be described, and which like the vertical pipe with which
it communicates, is of iron and enables the melted lead contained in the pot placed
above the level of the rest of the apparatus to enter and fill the space between the
circular plate, and so to produce upon the lower side of that plate the pressure due
to a column of lead. An iron plug forced and held into its place by a screw,
employed for the purpose of letting out the liquid lead from the cylinder and base,
and permit same to fall into a pan, whence it may be returned into the melting
pot. The loam lined cylinder being in its place, and the lead in the melting pot being
in fusion, and the pipe connecting same with the base of the cylinder as well as
the latter being preserved at a temperature above that at which lead is in perfect
fusion by means of Bunsen or other gas burners (one of which is immediately
beneath the base, or by the heat of ignited coke or other fuel), the loam lined top
cover of the similarly lined cylinder provided with a fosset fitting a conical spigot,
forming part of the mould box, is placed on the top flange of the cylinder and
secured down thereon by means of two jointed straps, each provided with a cotter
bearing upon lugs projecting from the cylinder cover, by which the cover is held
firmly down upon the cylinder and the base. A funnel formed of cast iron or of
sheet iron, thinly lined with clay wash properly dried (or altogether of baked clay
or clay and plumbago, or of the material of plumbago crucibles), is then placed in
the fosset, and through this the cylinder is to be filled full of the melted bronze or
other metal intended to be cast under pressure; the funnel is then withdrawn and
the spigot of the mould box to be inserted in the fosset of the cylinder cover, and
if necessary made stanch thereto by a little clay wash. The cock being opened the
descending column of liquid lead immediately fills the hollow base of the cylinder,
forces up the circular plate and the liquid bronze above it, and injects the latter
rapidly and forcibly into the mould.
For the purpose of more effectually guiding the circular plate in its upward

page_text: motion, and preserving its horizontality, a stem connected with the centre of the
plate, and tapered at its lower extremity, may be inserted into a hole in a vertical
direction provided in the base to receive it, the stem being of such a length that a
small part of its extremity shall still remain in the hole when the circular plate
shall have risen to the top of the cylinder. The cock is to be now closed, and the
melted lead which has displaced the bronze and forced it into the mould, and
which now fills the cylinder, is to be run off into the pan by means of the screw
plug. The straps holding down the cylinder and cylinder cover being now with-
drawn the cylinder cover is to be removed, and the neck or gate of bronze or other
metal which fills the adjutage is to be broken through, so as to detach the cylinder
cover from the mould box, which is easily done at a temperature a little below the
fusing point at which the bronze is brittle. The loam lined cylinder is to bo now
removed, and another similarly prepared along with another cover are to be fixed
in place upon the base, and being, in the manner already described, filled with the
melted bronze or other metal to be cast, the melted lead is again to be admitted
beneath the plate, and a new casting in another box made by repeating the process
as already described.
The capacity of the cylinder may be varied to suit the volume of melted bronzo
required to be cast by one operation, and more than one mould may be cast at the
same time by clamping or otherwise, securing together several moulds with inter-
communicating gates, all communicating with the adjutage in a box.
The box has its spigot in two parts, one on each half of the box, together making
a conical spigot turned to fit and make a stanch joint in the socket of the cover.
The box may be secured in its place by means of a weight placed on the upper part
or by clamps, or other means known to founders. By constructing the spigot of
the box thus in two parts the box can be opened, and the casting removed without
difficulty, in the event of the neck or gate of bronze not being broken through at
the proper moment while the metal is still brittle, in which case the neck or grate
is to be cut through by a circular saw or otherwise, when the cylinder cover can be
shipped off, and made ready to be used again by lining with loam.
It will be readily understood that the height of the lead pot can be varied, so as
to suit the pressure with which it is desired to inject the bronze or other metal into
the casting mould, the rule being that the height of the surface of the load pot
should be about 25 inches above the highest part of the casting when in the mould
box for each ten pounds pressure per square inch under which it may be determined
to make the castings, or in that proportion more or less.
The second arrangement, namely, that in which the hydrostatic pressure is
obtained by a weighted plunger forced down into liquid lead, is somewhat as
follows: The cylindrical plunger of cast iron works in a hollow cylinder also of
cast iron, which it enters through an ordinary gland or stuffing box packed with
asbestos, and beneath which is placed a steel ring. Upon the stem attached to the
upper end of the plunger a weight is placed, which presses it down. The stem
passes through a bush at the top of the framing surmounted by a standard carrying
a pulley or sheave, which conducts the chain connected to the stem down to a little
winch by which the weight and plunger are lifted.
The top of the plunger stem being seized by a claw, so constructed that upon
striking up a latch the claws open, and the weight and plunger drop, their descent
being checked by a collar coming in contact with a plate resting upon the cork
washer or buffer. The plunger being raised to its highest point by the arrange-
ment just described melted lead is permitted to enter and fill the cylinder in which
the plunger is to descend through a cock which is connected by an iron pipe to tho
melting pot. A screw plug is employed for letting out any air which may accu-
mulate in the upper part of the plunger cylinder.
The rest of the apparatus appertaining to this arrangement is the same as that
previously described, the plunger cylinder being connected by means of a cock and
pipe, so that on the descent of the plunger the melted lead is forced through tho
cock into the base of the clay lined cylinder full of bronze, all as already described.

page_text: The function of the weighted plunger and its adjuncts, as just described, being to
supply the place of the pressure of the insistent column of lead, so that all the parts
of the apparatus first described are also needed for the arrangement secondly
described, with the exception of the lead melting pot being no longer required to
stand at as great a height above the level of the clay lined cylinder, but only at
such a height above the level of the inlet cock as shall cause the lead to flow into
the plunger. The plunger cylinder and its adjuncts must be maintained above the
melting point of lead by means of one or more gas burners within the chamber, or
by a small fire of other fuel.
The third arrangement, by which the pressure of compressed air is employed in
licu either of the insistent lead column or the plunger to force the liquid lead beneath
the melted bronze in the cylinder, the lead melting pot and furnace are similar to
that before described, but placed close to and somewhat above the level of the
cast-iron cylinder, which is filled with melted lead from the melting pot by a short
connecting pipe and cock. The lowermost part of this cylinder is in connection by
a pipe with the inlet cock first described. At the top of the cylinder is a pipe,
which, with an intervening cock or air-tight valve of any well-known construction
communicates with a vessel of condensed or compressed air, the tension in which
must somewhat exceed the greatest pressure at which it is intended to force the
melted bronze into the mould. The cock, valves, and this compressed air vessel
may be of any suitable form; the capacity of the air vessel should be about twenty
times that of the cylinder, and the compressed air may be supplied by pumps of
well-known forms worked by hand or power.
The operation of this modification of the apparatus is as follows:-The clay lined
cylinder, and other parts herein-first described, being arranged in place, as described
already, the lead from the melting pot is permitted to flow into the cast-iron
cylinder through a cock, and pass thence through the pipe as far as the inlet cock in
the base of the clay lined cylinder first described. The cock communicating with
the melting pot and the cast-iron cylinder is now to be closed, and the cock being
opened, and the cylinder being already filled with melted bronze or other metal or
alloy, as described, the valve or cock communicating with the compressed air is to
be opened, so that the pressure of the condensed air may through the connecting
pipe act upon the surface of the liquid lead contained in the iron cylinder, and
forcing it through the inlet cock into the hollow base beneath the circular plate
force up the same, and inject the melted bronze, or other metal or alloy, into the
mould, as before described. In this arrangement the compressed air performs the
same function as the insistent column of lead in the arrangement first described, or
ns the weighted plunger does in the second described modification.
The details of construction of the cocks common to all the arrangements for per-
mitting the flow of liquid lead, or cutting it off, are as follows:-This cock is
altogether made of iron, and consists of a cylindrical pin partly contained within a
cylindrical barrel or casing, which forms part of the lead conducting pipe. This
barrel may be of cast iron, but the pin must be of wrought iron or steel. Trans-
versely through the pin is bored a cylindrical hole equal in diameter to the lead
conducting pipe. The movement of the pin of this cock is limited to one in the
direction of its own axis by a collar forged upon one end of the pin, and a collar at
the other end secured by a cross pin when the first-mentioned pin is moved in one
direction, as far as the first-mentioned collar will permit; the aperture through it is
fair with the bore of the communicating pipe or the cock is open. When the pin is
against the other collar the cock is shut, so that by this simple arrangement a tap
with a light wooden mallet on either one or the other end of the pin is sufficient to
inanipulate the cock. The pin is prevented from twisting when in its place by a
screw stud of iron or steel, which is tapped through the barrel or shell, and the
point of which enters a slot provided in one side of the cock pin, and of sufficient
length to admit of its end-on movements.
Ünder whatever modification of the apparatus all the parts receptive of the
melted lead must be kept constantly at or above the fusing point of that metal, and

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Benjanin Joseph Barnard Mills in the Great Seal Patent Office on the
1st September 1876.
BENJAMIN JOSEPH BARNARD MILLS, of the Firm of Harris and Mills, of 23,
Southampton Buildings, in the County of Middlesex, Patent Agent. " IMPROVE-
MENTS IN APPARATUS TO BE EMPLOYED WHEN CASTING METALS OR ALLOYS UNDER
PRESSURE." A communication from abroad by Pierre Ludovic Van den Bergho, of
Paris, in the Republic of France.
The Invention has for its object the casting metals or alloys under pressure in
general accordance with the methods Patented by B. J. B. Mills on the 11th day
of May 1869, No. 1443, and by James Mackintire on the 31st day of December,
1873, No. 4287, and on the 30th day of December, 1874, No. 4469, substituting,
however, for the cylinder and solid piston as therein described arrangements by
which a fluid piston, that is to say, the pressure given by or transmitted through
a column of a fusible metal such as lead or any suitable alloy thereof, shall
force the metal intended to be made into castings under pressure into mould or
moulds and shall give the requisite pressure to cause the same to fill the moulds
with exactness, and so produce that sharpness of contour which is the main
object of this method of casting.
In the accompanying Drawings three arrangements are shewn in detail for
casting under pressure by means of a fluid piston.
The apparatus for the first of these methods is shown in the Figures 1, 2, 3, and
4, and consists in bringing the hydrostatic pressure of a column of liquid lead of
sufficient height to press up the fused bronze, or other metal or alloy, and force it
into the mould. In the Figures 4 and 5 the hydrostatic pressure of the liquid
lead upon the melted bronze or other metal or alloy is produced by forcing a
cylindrical plunger into a close vessel containing the liquid lead in lieu of that
produced directly by a head or column of melted lead. And in Figures 7 and 8
the requisite pressure to force the melted bronze or other metal or alloy into the
mould is produced by compressed air acting upon the surface of the liquid lead and
through that upon the melted bronze or other metal or alloy.
I will now proceed to describe the several parts of these three differont modifica-
tions of apparatus and the mode of their operation.
The apparatus for the first of these methods is shewn in Figures 1, 2, 3, and 4.
Figure 1 is a vertical section of the apparatus generally; Figure 2 a side eleva-
tion of the same; Figure 3 an end elevation in a plane at right angles to the last
named; Figure 4 is a vertical section of the lead melting pot and the furnace beneath
it. a is a cylinder of cast iron with flanges at its top and bottom ends, and at the
bottom a flange or fillet 6 projecting inwards (see Figure 1). This cylinder is lined
with loam which is dried or baked within the cylinder and which must be cylindrical
or uniform in internal diameter when dried, such result being secured either by
pressing the still plastic loam lining in the cylinder upon a core afterwards to be
withdrawn or by "spinning" or by boring the interior surface of the dried loam by
turning in a lathe according to methods well known to moulders. The bottom or
lower end of this cylinder is closed by a thin circular plate c which may be of
bronze, copper, or sheet iron, or other suitable material, but iron is preferred. This
plate whose diameter must be slightly less than that of the finished loam lining of
the cylinder and the edge of which must be rounded rests all round near its edgo
upon the internal flango b projecting inwards already described.
The lining of the cylinder composed of a suitable mixture of fire-clay and sand
with or without a mixture of fibrous matter, and well known to founders as "loam,"
being completed and baked or dried, is to be given one or more. coats of that
.

page_text: composition of clay and pulverized coal and water well known to loam moulders as
"black wash," and the circular plate c having been previously covered with one or
more coats of the same which have been dried or baked upon it is to be dropped
into its place upon the fillet b while the "black wash" upon that is still wet, so that
the plate c may be rendered stanch to fluid metal at its junction with the cylinder
lining and the fillet b. The lined cylinder and plate with their coatings are now to
be thoroughly dried together in the stove. The surfaces of the flanges at the top
and bottom of the cylinder being faced in the lathe the lower flange is placed upon
a correspondingly faced recess provided in the cast iron based so that there is a
hollow space then enclosed beneath the sheet iron or other plate cwhich closes the
bottom of the loam lined cylinder a
At one side of the base there is a pipe e provided with an inlet cock f, con-
structed after the manner herein to be described with respect to Figures 9, 10, 11,
and 12, and which, like the vertical pipe e with which it communicates, is of iron,
and enables the melted lead contained in the pot g, Figure 4, placed above the level
of the rest of the apparatus, to enter and fill the space between the circular plate
c and so to produce upon the lower side of that plate the pressure due to a column
of lead e, c.
At h is an iron plug forced and held into its place by a screw, the
purpose of which is to let out the liquid lead when required from the cylinder a
and based and permit same to fall into the pan i, whence it may be returned
into the melting pot g. The loam lined cylinder a being in its place, and the lead
in the melting pot g being in fusion and the pipe connecting same with the base of
the cylinder d as well as the latter being preserved at a temperature above that at
which lead is in perfect fusion by means of Bunsen or other gas burners (of which
one is shewn at j, Figure 1, immediately beneath the base d, or by the heat of ignited
coke or other fuel), the loam lined top cover k of the similarly lined cylinder a,
provided with a fosset l, fitting the conical spigot o, forming part of the mould
box m is placed on the top flange of the cylinder a and secured down
thereon by means of the two jointed straps n, n, each provided with a cotter g
bearing upon the lugs p, projecting from the cylinder cover k by which the cover is
held firmly down upon the cylinder a and the base d. A funnel, Figures 15 and
16, formed of cast iron or of sheet iron thinly lined with clay wash properly dried
(or altogether of baked clay or clay and plumbago or of the material of plumbago
crucibles) is then placed in the fosset 1, and through this the cylinder a is to be filled
full of the melted bronze or other metal or alloy intended to be cast under pres-
sure; the funnel is then withdrawn and the spigot o of the mould box m is to be
inserted in the fosset 7 of the cylinder cover k, and if necessary made stanch thereto
by a little clay wash. The cock f, Figure 1, being opened, the descending column
of liquid lead immediately fills the hollow base of the cylinder, forces up the circular
plate c and the liquid bronze or other metal or alloy above it, and injects the latter
rapidly and forcibly into the mould.
For the purpose of more effectually guiding the circular plate c in its upward
motion and preserving its horizontality a stem, as in Figure 13, connected with the
centre of the plate and tapered at its lower extremity may be inserted into a hole
in a vertical direction provided in the base d to receive it, the stem being of such a
length that a small part of its extremity shall still remain in the hole when the
circular plate c shall have risen to the top of the cylinder a. The cock fis to be
now closed and the melted lead which has displaced the liquid bronze and forced it
into the mould, and which now fills the cylinder a is to be run off into the pan i by
means of the screw plug h. The straps n holding down the cylinder and cylinder
cover being now withdrawn, the cylinder cover k is to be removed, and the neck or
gate of bronze or other metal which fills the adjutage is to be broken through so as
to detach the cylinder cover from the mould box, which is easily done at a
temperature a little below the fusing point at which the bronze is brittle. The
loam lined cylinder is to be now removed and another similarly prepared along
with another cover are to be fixed in place upon the base d, and being in the
manner already described filled with the melted bronze or other metal to be cast,

page_text: the melted lead is again to be admitted beneath the plate c, and a new casting in
another box made by repeating the process as already described.
The capacity of the cylinder a may be varied to suit the volume of melted
bronze or other metal or alloy required to be cast by one operation, and more than
one mould may be cast at the same time by clamping or otherwise securing together
several moulds with intercommunicating gates, all communieating with the adjutage
on a box, as shown at o and b, Figure 1.
The box m has its spigot in two parts one on each half of the box, together
making a conical spigot turned to fit and make a stanch joint in the socket of the
cover . The box may be secured in its place by means of a weight placed on the
upper part or by clamps or other means known to founders. By constructing
the spigot of the box thus in two parts the box can be opened and the casting
removed without difficulty in the event of the neck or gate of bronze not being
broken through at the proper moment while the metal is still brittle, in which case the
neck or gate is to be cut through by a circular saw or otherwise, when the cylinder
covor k can be shipped off and made ready to be used again by lining with loam,
as shewn in Figure 1. Thus the inconvenience called "rivetting" is avoided.
It will be readily understood that the height of the lead pot g can be varied, so as
to suit the pressure with which it is desired to inject the bronze or other metal into
the casting mould; the rule being that the height of the surface of the lead pot
should be about 25 inches above the highest part of the casting when in the mould
box, for each ten pounds pressure per square inch under which it may be determined
to make the castings or in that proportion more or less.
Figures 5 and 6 shew the second arrangement, namely, that in which the
hydrostatic pressure is obtained by a weighted plunger forced down into liquid lead ;
Figure 5 is a vertical section; and Figure 6 is an elevation in a vertical plane at
right angles to that of Figure 5. The cylindrical plunger a, Figure 5, of cast iron
works in the hollow cylinder b, also of cast iron, which it enters through an ordinary
gland or stuffing box c packed with asbestos d, and beneath which is placed a steel
ring e seen in the separate Figure 17, and at e, e, in the section. Upon the stem ƒ
attached to the upper end of the plunger a a weight w is placed which presses it
down. The stem passes through the bush h at the top of the framing a surmounted
by a standard k, carrying a pulley or sheave i which conducts tho chain down to
the little winch m, by which the weight and plunger are lifted.
The top of the plunger stem f being seized by a claw n, Figures 5 and 14, so
constructed that upon striking up the latch o the claws n open and the weight and
plunger drop, their descent being checked by a collar t coming in contact with the
plate y resting upon the cork washer or buffer x. The plunger a being raised to
its highest point by the arrangement just described melted lead is permitted to
enter and fill the cylinder b in which the plunger a is to descend through the
cock p, which is connected by an iron pipe to the melting pot g (Figure 4). The
screw plug n in Figure 6 is employed for letting out any air which may accumulate
in the upper part of the plunger cylinder b.
The rest of the apparatus appertaining to this arrangement is similar to that
shown by the Figures 1, 2, 3, 4, the plunger cylinder being connected by means of
the cock f Figure 1, and pipe g, Figure 6, so that on the descent of the plunger a
the melted lead is forced through the cock f, Figure 1, into the base of the clay
lined cylinder a full of melted bronze or other metal or alloy, all as already described.
The function of the weighted plunger and its adjuncts as just described being to
supply the place of the pressure of the insistent column of lead (of the height e, e,)
as shewn in the Figures 1 and 4, so that all the parts of the apparatus first described
and shown at Figures 1 to 4 are also needed for the arrangement shown and
described with respect to Figures 5 and 6, with the exception of the lead melting
pot g, Figure 11, being no longer required to stand at as great a height above the
level of the clay lined cylinder a, Figure 1, but only at such a height above the
level of the inlet cock p, Figure 6, as shall cause the lead to flow into the plunger
cylinder b, Figures 5 and 6. The plunger cylinder and its adjuncts must be

page_text: maintained above the melting point of lead by means of one or more gas burners
within the chamber r, Figures 5 and 6, or by a small fire of other fuel.
In Figures 7 and 8 are shewn the details of the apparatus by which the pressure
of compressed air is employed in lieu either of the insistent lead column e, e,
Figures 1 and 4, or the plunger a, Figure 5, to force the liquid lead beneath the
melted bronze in the cylinder a, Figure 1. E, Figure 7, is a vertical elevation, and
H, Figure 8, a plan of the lead melting pot and furnace, similar to that in Figure 4,
but placed close to and somewhat above the level of the cast-iron cylinder a, shown
in section at Figure 7 and in plan in Figure 8, which is filled with melted lead or
other readily fusible metal or alloy from the melting pot g by the short connecting
pipe and cock b. The lowermost part of this cylinder a, Figure 7, is in connection
by the pipe e, Figure 7, with the inlet cock f, Figure 1. At the top of the cylinder
a, Figure 7, is a pipe d, which, with an intervening cock or air-tight valve of any
well known construction, communicates with a vessel of condensed or compressed
air, the pressure in which must somewhat exceed the greatest pressure at which it is
intended to force the melted bronze into the mould. The cock, valve, and this com-
pressed air vessel, which may be of any suitable form, are not shewn in the Draw-
ing the capacity of the air vessel should be about twenty times that of the
cylinder a, Figure 7, and the compressed air may be supplied by pumps of well
known forms worked by hand or power.
The operation of this modification of the apparatus is as follows:-The clay lined
cylinder and other parts shewn in group, Figures 1 to 4, being arranged in place, as
described already, the lead from the melting pot g, Figure 7, is permitted to flow
into the cast-iron cylinder a, Figure 7, through the cock h, and pass thence through
the pipe c, Figure 7, as far as the inlet cock fin the base of the clay lined cylinder
a, Figure 1. The cock communicating with the melting pot g and the cast-iron
cylinder a, Figure 7, is now to be closed, and the cock f, Figure 1, being opened, and
the cylinder a, Figure 1, being already filled with melted bronze or other metal or
alloy, as described, the valve or cock communicating with the compressed air is to
be opened, so that the pressure of the condensed air may through the pipe d,
Figure 7, act upon the surface of the liquid lead contained in the iron cylinder a,
Figure 7, and forcing it through the inlet cock f, Figure 1, into the hollow base"
beneath the circular plate c force up the same and inject the melted bronze or other
metal or alloy into the mould, as before described. In this arrangement the compressed
air performs the same function as the insistent column of lead e, e, in the arrangement
shewn in Figures 1 and 4, or as the weighted plunger a does in Figures 5 and 6.
Figures 9, 10, 11, and 12, show the details of construction of the cocks common to
all the arrangements for permiting the flow of liquid lead or cutting it off. This
cock is altogether made of iron and consists of a cylindrical pin a, partly contained
within a cylindrical barrel or casing b, which forms part of the lead conducting pipe.
This barrel may be of cast iron, but the pin a must be of wrought iron or steel.
Transversely through the pin a is bored a cylindrical hole c equal in diameter to the
lead conducting pipe. The movement of the pin of this cock is limited to one in
the direction of its own axis by a collar d forged upon one end of the pin and collar
e at the other end, secured by a cross pin f, when the pin a is moved in one direction
as far as the collar e will permit, the aperture c through it is fair with the bore g of
the communicating pipe, that is to say the cock is open. When the pin is against
the other collar d the cock is shut, so that by this simple arrangement a tap with a
light wooden mallet on either one or the other end of the pin is sufficient to mani-
pulate the cock. The pin a is prevented from twisting when in its place by a screw
stud h of iron or steel, which is tapped through the barrel or shell b, and the point
of which enters the slot a provided in one side of the cock pin a, and of sufficient
length to admit of its end-on movements, as seen in Figure 12. Figure 9 is a section
through the bore of the cock pipe at right angles to the pin. Figure 10 is an eleva-
tion of the cock in the same direction. Figure 12 is a partial section of the cock
in a plane passing through the axis of the pin. Figure 11 is an end elevation of the
cock in a direction parallel to the pin.

page_text: Under whatever modification of the apparatus all the parts receptive of the melted
lead must be kept constantly at or above the fusing point of that metal, and the
clay lined cylinder a, Figure 1, should be put in its place and brought into use at as
nearly the same temperature as may be convenient.
Having thus described the nature of the said Invention, and the mode in which
the same may be carried into effect, I would have it understood that what I claim
is,―
Casting molten metals or alloys by causing them to be injected into and per-
fectly to fill the properly prepared moulds, whether formed as described in the said
patent of B. J. B. Mills, or James Mackintire, or otherwise, by the fluid or hydro-
static pressure of a fusible metal such as lead or some of its alloys with tin, being
in a liquid state, by means of the apparatus and operations described (which may bo
varied as to many of the details) or by means of any apparatus and operations
substantially similar.
I also claim the improved arrangement of adjutage both as respects the cylinder
cover and as respects its division between the separate parts of the mould boxes,
by which increased facilities for perfect casting are obtained, and for the separation
of the cylinder and gate from the casting when made, and from the remains of
bronze or other metal or alloy, if any, within the cylinder cover.
In witness whereof, I, the said Benjamin Joseph Barnard Mills, have hereunto
set my hand and seal, this Thirtieth day of August, in the year of our Lord
One thousand eight hundred and seventy-six.
B. J. B. MILLS. (LS.)