IMPROVEMENTS IN THE CONSTRUCTION AND ARRANGEMENT OF APPARATUS FOR HEATING AND MELTING METALS IN CRUCIBLES
Year: 1877

page_text: LETTERS PATENT to Thomas James Smith, of the Firm of Robertson,
Brooman, and Company, of 166, Fleet Street, in the City of London, Patent
Agents, for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION AND
ARRANGEMENT OF APPARATUS FOR HEATING AND MELTING METALS IN
CRUCIBLES." Communicated from abroad by Albert Piat, residing at Rue des
Halles, Paris, France.
Sealed the 16th March 1877, and dated the 5th January 1877.
PROVISIONAL SPECIFICATION left by the said Thomas James Smith at
the Office of the Commissioners of Patents on the 5th January 1877.
THOMAS JAMES SMITH, of the Firm of Robertson, Brooman, and Company, of 166,
Fleet Street, in the City of London, Patent Agents. "IMPROVEMENTS IN THE CONT
STRUCTION AND ARRANGEMENT OF APPARATUS FOR HEATING AND MELTING METALS
IN CRUCIBLES." Communicated from abroad by Albert Piat, residing at Rue des
Halles, Paris, France.
This Invention relates to improvements in the construction and arrangement of
apparatus for heating and melting metals in crucibles, and consists of upright
bearings supporting trunnions on to which is fixed a cylindrical casing lined with
a refractory material, and forming a chamber in which the crucible is placed, a
space being left all round for the reception of the fuel by which the crucible is to be
heated.
Below the casing is a kind of jacket, which when the casing is in a vertical posi-
tion closes in the bottom, and forms a chamber leading to a channel through which
atmospheric air can enter to support combustion.
The air may be natural or under pressure, the channel having two gates which
can be opened or closed to suit.
The casing is open top and bottom, and one end is temporarily closed by a plug
of refractory material held in place by cross bars or other appliance, the plug serving
to support the crucible. The other end of the casing is provided with a plug or

page_text: stopper, preferably of metal floated with a refractory material. This stopper has
holes in it at the sides for the passage of air to the fuel in the fuel chamber, and it
forms what might be termed a cap to close up the end of the crucible. The cap has
a spout or "tap hole" through or from which the fluid metal can be poured when in
a liquid state, this hole being closed by a plug in the usual manner.
When the apparatus is at work the casing and the crucible are inverted, the
stopper forming the bottom for the time being, and the melting of the metal is
carried on while in this position; but when the metal has to be poured into
moulds the apparatus is turned proper way up and tilted to discharge the metal, as
desired.
On turning the apparatus proper way up the stopper is removed and an obturator
or lid is put in its place, which preserves the heat and permits of the pouring being
effected.
The crucible is held firmly in position on the plug as a base by adjustable side
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas James Smith in the Great Seal Patent Office on the 5th
July 1877.
THOMAS JAMES SMITH, of the Firm of Robertson, Brooman, and Company, of 166,
Fleet Street, in the City of London, Patent Agents. "IMPROVEMENTS. IN THE CON-
STRUCTION AND ARRANGEMENT OF APPARATUS FOR HEATING AND MELTING METALS
IN CRUCIBLES." (Communicated from abroad by Albert Piat, residing at Rue des
Halles, Paris, France.)
This Invention relates to the construction or combination of a crucible proper
within a furnace or casing containing fuel, by which the crucible can be heated and
metals melted therein, and from which the fluid metal can be poured by tilting the
furnace and crucible only as an apparatus in itself, either on bearers at the spot
where the melting takes place, or at a distance by conveying it suspended to the
spot desired, the furnace and crucible as one apparatus being of a portable and
movable character, independent of any separate carriage, or lower frame, or part of
the stack, to render it available for castings of high class order.
According to one arrangement I arrange fixed and immovable uprights as fixed
appendages to the stack, said uprights forming supports or bearings on to which is
temporarily hung by its axle arms or trunnions a cylindrical or other shaped casing
(furnace), lined or not with a refractory material, and forming a chamber in which
the crucible is placed, a space being left all round between the crucible and the
lining for the reception of the fuel by which the crucible is to be heated, aided or
not by a blast.
Below the casing is a kind of jacket, which when the casing is in. a vertical
position closes the bottom by a luting at the joint or seam, and forms a chamber
leading to a channel through which atmospheric air can enter to support com-
bustion.
The air may be natural or under pressure, the channel having two gates, which
can be opened or closed to suit.
. The casing is open ended top and bottom, and both ends can be temporarily closed
by plugs or stoppers held in place by cross bars or other appliances. To support
the crucible therein one of the stoppers is preferably of metal floated with a refrac-
tory material, the other being wholly of refractory material. The metallic stopper
has holes in it at the sides for the passage of air to the fuel in the fuel chamber, and
it forms what might be termed a cap to close up the end of the crucible, and also
that end of the casing. When this cap is removed, as herein-after explained, the
spout or tap hole" of the crucible becomes uncovered to enable the fluid metal to

page_text: be poured into moulds or other receptacles, the top of the casing being however
closed by a plug of refractory material to prevent loss of heat and to prevent the top.
surface of the metal being chilled or otherwise acted upon by atmospheric air before
the pouring can take place, whether the crucible be tilted upon its bearings to pour
the metal out, or the crucible and casing as one article be carried to the moulds.
When the apparatus is about to be set to work, the casing and the crucible,.
according to one method, are inverted, the cap or stopper forming the bottom for the
time being. The fuel is then put into the chamber between the crucible and the
lining of refractory material and lighted in order to heat the crucible to the desired
degree, this being aided by a blast through the apertures in the cap stopper if
necessary. The other end of the casing is during this process open, or it may be
closed by a plug with apertures in its flange for the passage of the products of com-
bustion to the chimney.
When the desired heat is obtained the apparatus is turned on its bearings, the
plug being by this time fitted in to bring the crucible the proper way up; the cap
stopper is then removed to enable the chamber to be filled up with fuel, and the
metal to be melted inserted into the crucible. The top of the apparatus is then
closed by an obturator or lid, a chamber being left under it in which the flame can
play to establish a top heat upon the metal within the crucible. When the metal is
sufficiently fused the spout or tap hole is tapped (if it has been closed), and the apparatus
tilted on its bearings to pour the fluid metal into moulds brought under it for the
purpose, or it may be carried by suspension to the moulds, as before explained.
The crucible is held firmly in position on the plug as a base by adjustable side
pieces.
This Invention will be clearly understood by the aid of the annexed Drawings,
Figures 1 and 2 in section, which represent one arrangement of enclosed crucible
for melting metals, and from which the metal can be poured without removing it
from the casing in which it has been heated by the surrounding fuel assisted by a
current of air, as before described.
A is the crucible or melting pot, here shown of conical bellied form, but it may be
of any shape.
B is a casing, preferably of sheet iron, within which is a lining of fire-clay or
refractory material C of such a thickness as to leave a chamber between it and the
crucible for the reception of coke or other fuel D.
The pot A in Figure 1 is shown resting upon a hollow cap or stopper E, the
present upper part F of which is floated with a refractory body if the cap be made
of iron; this cap E is held in position in the end of the casing by fitting in a rim
piece G and by cross bars H, of which there are two, as in Figure 2, for the purpose..
The opposite end of the casing is also closed by a plug I, which rests upon the
proper bottom of the crucible, and is held firmly in that position by fitting in a
rim or plate J and by cross bars K, of which there are two, as is also shown in
Figure 2.
The plate J has holes to correspond with other holes in the plug flange M to
permit the waste gases to pass away to the chimney or up-take while the crucible is
being heated.
The casing, in which the crucible or melting pot A thus held free from contact
with external air by the joints or seams being luted, is arranged with a band or
lugs N, having trunnions or axle arms P, P, attached to enable it to be suspended
upon forked bearings Q, Q, of standards or uprights R, R, and upon which the casing
with the crucible can be turned as on a centre or pivot when desired.
The trunnions terminate in square or other shaped ends, over or on to which
sockets or clips of long arms can be shipped, and by which the furnace can be lifted
from the bearings and be carried to the moulds into which the fluid metal from the
crucible has to be poured.
While the casing is in the position shown in Figure 1, and the work of heating is
proceeding, the casing is locked securely by the key or bolt S, the seam or meeting

page_text: edge of the casing and of the blast chamber T being luted to prevent escape of air
at that part.
The blast comes into the chamber T by the pipe U, shown in Figure 2, from a
blower or fan. The pipe U is provided with a gate or valve V to regulate the feed
and to shut it off when desired, such as when the melting is complete, or when the
same blast feeds several crucibles, as is common in foundries.
The cap E is loosened by the removal of the cross bars H and an obturator or
lid W, Figure 2, fitted in and locked by the re-insertion or refixing of the cross bars.
By this means the top heat becomes retained on the fluid metal; the long arms are
then slipped on to the trunnions, as in the plan view, Figure 4, and in some cases
keyed to fix them to enable the crucible to be tilted on the trunnions and standard
bearings, and the fluid metal to be poured into moulds or boxes brought to the
furnace, or for the furnace to be lifted off and carried to the moulds or boxes,
which may be in another part of the foundry. The furnace thus portable can be
lifted off and carried even into exposed situations without chilling the fluid metal
or in any way interfering with the heat of the crucible proper on account of the
surrounding body of fuel, which remains incandescent by reason of all apertures
being closed by the obturator and there being no atmospheric contact, and by reason
of the great heat of the refractory material lining of the casing, which is also not
exposed to the atmosphere.
It is essential that moulds to be charged with fluid metal should be clean and
free from dust; also that the moulds should not be shaken or moved, more especially
with high class castings, such as ornamental work, mountings, statuettes, and other
metallic works of art usually in bronze, for which this Invention is more particularly
intended.
The great value and importance of this Invention is conceivable from the facility
it affords of conveying highly fused true liquid metal to moulds in rooms and places
not subjected to the deposit of floating dust and the rough usages generally found
in open foundries and the like.
Figure 3 of the annexed Drawings represents a section of a portable crucible and
furnace combined, in which the cap E is fitted for the bottom proper of the crucible to
rest upon, in contradistinction to the top proper, as in Figure 1. In this arrangement
(Figure 3) the crucible is brought up to the desired heat while in the position shown
in contradistinction to being inverted, as in Figure 1. The mouth or top of the
crucible is hermetically closed for the first heating, when the apparatus is inverted
by an intermediate obturator Y, on which the lid W is caused to bear by the cross
bars H, H; this obturator is removed when the apparatus is rotated on its uprights
R, R, Q, Q, and the top lid W re-adjusted.
The first heating of the melting process may however be conducted with regard
to Figures 1 and 2, and also Figure 3, by supplying the air to one end of the furnace
only, namely, at the bottom end of the crucible. In this case no reversing of the
apparatus is necessary.
When the desired heat of the crucible is attained, the lid W and plug Y are
removed, the chamber is filled up with fuel, and the metal to be melted is inserted
in the crucible. The lid W only is then put on, and the fusion proceeds as described
with reference to Figure 2.
This crucible has an aperture a at the bottom on one portion of its smaller dia-
meter, and another aperture 6 at the upper part or larger diameter, the two
apertures leading to a branch pipe c of the same or like material as the crucible
itself, of which it, when set in the furnace, forms a part. The branch pipe c ter-
minates in a spout or "tap hole" d for directing the fluid metal from the crucible
into the moulds or boxes when the apparatus is tilted, as shown by the dotted lines
in Figure 3.
e represents in Figures 2 and 3 a fire-brick stud to retain the top of the crucible
within the furnace securely by an outside screw f.
In the construction, Figure 3, of which Figure 4 is a plan with the long arms Z

page_text: affixed on the axles P, P, the air for supporting combustion of the fuel passes from
the chamber T through the apertures or orifices in the cap-shaped bottom support E
to the fuel D, from whence the escaping gases pass away to the chimney by holes in-
the rim G or lid W, which lioles can be temporarily stopped by plugs in the usual
manner to prevent loss of heat while the apparatus is being carried to the moulds or
casting boxes.
The crucible shown in Figure 3 has two apertures a, b, but only one of them may
be required for some kinds of metal, and then it is preferable to have one at the
bottom only, so that as the metal becomes fluid it may charge the lower part of the
pipe c, and thus by its being thinner in bulk be acted upon with greater force by
the heat of the fuel as to not only liquify itself the sooner, but impart its heat to the
newly formed fluid metal which is in bulk in the body of the crucible, at the same
time keeping the scum or dross in the body of the crucible.
g is a grate by which an ordinary feed of air to the furnace can be established.
The foregoing description refers to the Invention according to two methods which
have been found practically useful, but I do not limit myself to the exact shape of
the apparatus shown in the Drawings nor to the arrangements in detail, as many
changes can be made in the shape of the crucible, the number of its outlets, and in
the casing without departing from the nature of the Invention, which is clearly set
forth.
I am aware that suggestions have been made from time to time, notably in
Percy's Metallurgy, and in two instances provisional applications have been deposited
in which a crucible within a furnace with a degree of portability is explained, con-
sequently I make no claim in the broad sense to a crucible within a furnace of a
portable character.
The chief novelty in this Invention is arranging a crucible within a furnace or
casing which can be supported and turned on fixed standards at or from about the
central or balancing part of said furnace, in order that when removed by hand from
the fixed uprights it can be carried as one article by hand or otherwise to the
moulds if desired, and be then tilted to pour the metal from the crucible inde-
pendently of the uprights of the bottom air casing or of any part of the stack, and
without any bottom or other carriage as part thereof, the furnace and crucible being
as one article independent of other accessories, as before explained.
Having now described the nature of the said Invention and the manner in which
the same is to be performed, I declare that I claim as the Invention communicated
to me be by Albert Piat as aforesaid, and as secured by the part herein-befort recited
Letters Patent,-
Firstly. The improvements in the construction and arrangement of apparatus for
heating and melting metals in crucibles, as herein-before set forth and substantially
as shown in the annexed two Sheets of Drawings, especially a crucible or melting
pot in combination with a furnace, the two as one article being independent of a
carriage or other appliances as part thereof for its transport, except the axle arms or
trunnions, by which it can be placed upon forked supports for the heating operation
and be turnable thereon, and from which it can be lifted and detached to make it
movable and removable or portable in a suspended form, as described, without
reference to the shape of the crucible or of the furnace.
Secondly. The "first heating" of an enclosed crucible and its contents, if any, by
surrounding fuel and air, the apparatus, viz., furnace and crucible, being inverted
and the crucible mouth closed by an obturator having perforated sides through
which air can pass from a supply, as described and as shown in Figure 1.
Thirdly. I claim completing the heating or melting of metals in enclosed crucibles
turned proper way up for this treatment after first heating, as set forth, and after
the removal of the obturator and the reclosing of the top opening, as described with
reference to Figure 2.
Fourthly. I claim the application or employment of crucibles within portable
furnaces, said crucibles having openings at or near the bottom from which by an

page_text: attachable pipe spout arrangement the fluid. metal can be poured into moulds, or as
desired. With this system I especially claim the crucible and pipe shown in
Figure 3 of the annexed Drawings.
In witness whereof, I, the said Thomas James Smith, have hereunto set my
hand and seal, this Twenty-eighth day of June One thousand eight hundred
and seventy-seven.
T. J. SMITH. (L.S.). ·