IMPROVEMENTS IN CRUCIBLES AND PORTABLE FURNACES FOR THE SAME
Year: 1876

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
•
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS IN
CRUCIBLES AND PORTABLE FURNACES FOR THE SAME." A communication
from abroad by Alexandre Jules Plichon and Casimir Louis Thuau, both of
Paris France.
Sealed the 13th July 1877, in pursuance of an Order of the Lord Chancellor, and
Sealed the 13th July 1877, in pursuance of an Order of the Lord Chancellor, and
dated the 14th December 1876.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 14th December 1876.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN CRUCIBLES AND PORTABLE FURNACES FOR THE
SAME." A communication from abroad by Alexandre Jules Plichon and Casimir
Louis Thuau, both of Paris, France.
This Invention relates to improvements in crucibles, and consists mainly in
providing the crucible with means for keeping back the dross or scum when pouring,
in making the crucible portable and oscillating, and providing it with a heater and
special arrangement of tuyeres for avoiding the cracking of the crucible by the blast
striking against it.
The accompanying Drawings represent one arrangement of the crucible of this
Invention.
Figure 1 is a central vertical section, and Figure 2 a plan of the crucible.
Figure 3 is a plan of the tuyeres, the crucible being removed.
Figure 4 is a transverse section of the crucible cover.
Figure 5 is a sectional elevation taken through the axis of the air circulation
pipes.
Figure 6 shows the air supply pipe; and Figure 7, a longitudinal section, showing
the mode of connecting the air supply and circulation pipes.
Figure 8 is a plan of the forked shank or handle, by which the crucible is tilted
for pouring.

page_text: The same letters of reference are used to indicate the same parts in all the
Figures.
a is the crucible provided with two spouts or channels b, b, at opposite sides,
communicating with the interior of the crucible at its lower part by openings c, c,
of round or preferably of oval form, so that by inclining the crucible to one side or
the other the pure melted metal at the bottom will run out through the spout b, the
dross or scum which floats on the surface being retained. The crucible is made
portable and oscillating by addition of the heating chamber, which has two
trunnions and a hoop d provided with handles, and which receives these trunnions,
and enables two men to carry the crucible and tilt it in either direction.
The heater consists mainly of a casing, on the bottom of which is placed the
tuyere provided with a nozzle pipe g for the introduction of the blast, and con-
sisting of two compartments, viz., a lower one / receiving, the metal which flows
down through channels i in the event of the fracture of the crucible, and out of
the sliding door j, and an upper compartment & forming a reservoir for the blast,
which passes through a nuinber of openings in the cover m into the heating
chamber n. The gases of combustion from the latter pass through a passage o into
the ash-pan, and in so doing serve to heat the air blast. The crucible is fitted in a
socket in the top of cover m, having a hot-air circulation. The tuyere is screwed
to the casing.
By the aid of the cover m the air is prevented from impinging against the red-
hot crucible, and injury to the latter is thus avoided. Coke is placed around the
crucible in chamber m, which is then covered by a plate p of fire-clay. The interior
is also lined with fire-clay, care being taken to provide gutters on cover m leading
to the discharge channels. When pouring the cover p is removed, and a cast-iron
cover also lined with fire-clay substituted, said cover being secured by a cross
bars having a circular movement, and fixed by a key bolt t, and a screw u passing
through a nut at the centre of the bar, serving to press the cover down upon the
crucible, and the latter upon the socket of the air reservoir. The screw u is con-
nected to cover r, and the latter is provided with a pin v passing through a hole in
the bar s, so that the cover will partake in the rotary movement of the said bar.
ac, a, openings in the cover through which the spouts b project; y, horizontal pipo
introducing the air blast, to which are connected elbow pipes fitted with a valve 1,
and connected telescopecally with the tuyere of the crucible, as shown in Figure 7.
A number of these crucibles may be connected with the same horizontal pipe y on
either side of same.
Before pouring, the crucible is slightly withdrawn, and the elbow pipe z then
drops into a cavity in the ground, and the crucible may then be transported where
required. The crucible if of large dimentions would be suspended from a crane.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by 4
the said Alexander Melville Clark in the Great Scal Patent Office on the
14th July 1877.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN CRUCIBLES AND PORTABLE FURNACES FOR THE
SAME." A communication from abroad by Alexandre Jules Plichon and Casimir Louis 4
Thuau, both of Paris, France.
This Invention relates to improvements in crucibles and in portable crucible
furnaces for melting metals.
The improvements consist,-
First. In providing the crucible with means for keeping back the dross or scutit 5
when pouring the inetal into moulds.

page_text: Secondly. In a crucible furnace made portable as a whole without the addition of
any other apparatus, and provided with specially arranged chambers and passages,
for heating the air blast by the oscaping products of combustion, for supplying
heated air to the furnace in such way as to avoid the liability of the crucible to
crack, to which it is subject if a blast of cold air strikes against it, and for con-
veying away the molten metal should the crucible happen however to crack.
The accompanying Drawings represent the improved portable furnace and crucible
of this Invention.
Figure 1 is a central vertical section, and Figure 2 a plan of the crucible and
furnace.
Figure 3 is a plan of the furnace, the crucible being removed to show the sloping
top of the air chamber and the apertures or tuyeres therein.
Figure 4 is a transverse section of the crucible cover, showing the means for
securing it.
Figure 5 is a vertical section of a part of the furnace taken through the axis of
the coil, in which the incoming blast is heated by the escaping products of com-
bustion.
Figure 6 represents the air supply pipes; and Figure 7 is a longitudinal section
showing the way the air supply pipes are connected to the coil in which the air is
heated, as above mentioned.
Figure 8 is a plan showing the hoop which embraces the furnace, and has two
pairs of handles attached, by which the crucible furnace is carried about and tilted
like a foundry ladle for the purpose of pouring the metal from the crucible into the
moulds.
The same letters of reference indicate the same parts in all the Figures.
a is the crucible provided with two spouts or channels b, b, at opposite sides, and
which communicate with the interior of the crucible at its lower part only by
openings c, c, of round or oval form, so that when the crucible and furnace are tilted
to either side the pure metal at the bottom of the crucible only will run out through
the spout, the dross or scum which floats on the surface being kept back and
retained in the crucible. This is a great advantage, as it enables pure metal to be
obtained at once, and obviates the necessity of skimming the metal in the crucible.
The crucible a is fixed in a heater or furnace constructed of a cylindrical casing n
of sheet iron, with two lugs n' fixed on it, embraced by the hoop d, with handles
like a foundry ladle, by which the furnace is carried and tilted. On the bottom f' is
placed an air chamber k having a top or cover m inclined downwards towards the
sides. At the centre of this cover a socket is formed to receive the bottom of the
crucible, with a space 2 beneath it for the circulation of the heated air which enters
by a hole 3, and passes out at holes 4 into the furnace chamber n filled with coke
around the crucible. are orifices in the cover m surrounded by flanges to direct a
blast of hot air upwards through the fuel, and to prevent the molten metal running
into chamber k in the event of the crucible cracking, the cover m to guard against
this contingency being moreover provided with gutters leading to escape holes or
passages i communicating with a chamber h beneath the bottom f, and provided
with a sliding door j. The heated blast after performning its duty in the furnace
and the gases of combustion pass from the furnace chamber n, down through the
passages into the lower chamber h, and thence through an aperture o into a
casing 5 fixed outside the casing n, and containing a coil of pipe g', through which
the air blast passes, and thus becomes heated on its way into the chamber k. The
casing 5 has a vertical partition 6 to cause the gases of combustion to pass up one
side and down the other before escaping. p is a fire-clay cover for the crucible and
furnace during the melting operation. The interior of the furnace chamber is also
lined with fire-clay before placing the crucible and fuel therein.
Before pouring the metal out of the crucible the cover pis replaced by a cast-iron
cover r, Figure 4, which closes the crucible, with the exception of the spouts, which
pass through openings x, x, in the cover. The cover is lined with fire-clay, and
secured by a cross bar s, pivoted at one end and locked at the other by a key bolt t,

page_text: the cover being pressed down upon the crucible by a screw u passing through a nut
in the bar, whereby the crucible is held firmly in place when the furnace is tilted.
The screw is connected to the cover, and the latter has a pin passing through a
hole in the bar, so that the cover moves with the bar. The air is conveyed from a
fan through a horizontal pipe y, and elbow and other pipes z provided with
a valve, and fitted together so as to slide telescopically, as in Figure 7, to admit of
the spigot end being readily inserted and removed from the socket g. The
crucible furnace stands upon the ground, and in order to convey it to the moulds it
is withdrawn to detach the pipe ¹, which then falls into a cavity in the ground, so
as to be quite out of the way of the crucible furnace, and the escape of air through
it is prevented by the closing of the valve 1. A crane may be employed for moving
the furnace about when of large dimensions.
I may modify the furnace above described by making the air chamber at the
bottom of the furnace, and the casing containing the air heating coil detachable, so
as not to be moved about with it.
Having described the nature of the said Invention, and the manner of performing
the same, I would observe that I am aware of the Provisional Specifications of
W. H. Brown, dated June 22nd, 1854, No. 1370, and T. A. Rochussen, dated
September 21st 1864, No. 2318, and I am also aware that portable crucible furnaces
for laboratory use have been described in "Percy's Metallurgy;" and, further, in
pursuance of a condition imposed by Her Majesty's Attorney-General, I declare
that, notwithstanding anything herein contained, I do not claim any contrivance or
combination covered by the following description of an Invention "Which 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 or 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
position 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 at the 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 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 forins 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 pieces;" but what I claim as the Invention to be pro-
tected by the herein-before in part recited Letters Patent is,-
"
"
"
"
First. Providing the crucible with spouts which communicate with the interior
of the crucible at the lower part only, substantially as and for the purpose
specified.
Second. A furnace having a crucible fixed therein, and capable of being carried
and tilted as a whole by hand like a foundry ladle, substantially as and for the
purpose specified.
Third. A portable crucible furnace constructed and operating substantially as
herein shown and described.

page_text: Fourth. The method of and arrangements for causing the incoming air for com-
bustion to become heated by the escaping gaseous products of combustion.
Fifth. The means for carrying off the molten metal in the event of the crucible
cracking, substantially as herein specified.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Fourteenth day of July, in the year of our Lord One
thousand eight hundred and seventy-seven.
15 AT DV
A. M. CLARK. (L.S.)