Year: 1893

page_text: Figure 2-represents a vertical central longitudinal section of the same;
Figure 3-represents a perspective view of a modified form of the same with the
side partly broken away.
Figure 4-represents a vertical central section through another modified form of
the same;
Figure 5-represents a detail view of one of the conducting plates and,
Figure 6-represents a vertical section of the modification shown in Figure 3
on a plate taken along the axis of tube indicated by the line 2-2 of the latter
figure preferably in the form of a broad shallow inverted basin, having a
depression a in its top surrounded by a rim a'. This depression is provided with
an insulating lining A', if as is generally most convenient, the said base be made of
metal or other conducting material. Of course the lining A' will not be needed
when-a-base-of-pottery or other non-conducting material is used.
B designates the heating shell hollow-forge-or-receptacle which fits at the
bottom into the side depression; and consists of two end sections BB and inter-
vening insulating material B³. The latter is an U-shaped strip of fire clay or its
equivalent. The end sections B' B2-which may be side sections if preferred-are
moulded from a mixture of fire clay and graphite. The proportion of one of the
former to four of the latter will suffice. This makes a conductor of high resistance
giving forth a considerable quantity of heat. In each of these sections a copper or
other plate C of high conductivity is embedded. The ends of these plates are
allowed to protrude from connection to wires D D' completing, directly or
indirectly, the circuit through the generator of electricity. The said connection
may be made by clamps, as in the application aforesaid or in any other convenient
manner.
E designates a bed of pulverized graphite or other material of similar electrical
conductivity and resistance, filling the interior of the said shell or heating
receptacle below and around a stove crucible F which, as shown in Figure 2, is set
freely and centrally into the said bed. In Figure 4 the position of the crucible F¹
is the same but it is secured at its bottom rigidly by a post or stud to the
insulating strip B2, the said crucible insulating strip and stud being of fire-clay and

page_text: preferably in one piece. In this instance the crucible, not being removable, is
provided at its bottom with an outlet tube g which extends obliquely outward and
downward through the wall of the heating receptacle to incidentally acting as an
additional brace or fastening for the crucible and allows the molten metal to flow
out of the apparatus from the interior of the said crucible. The said tube is kept
plugged with fire clay until the time for such outflow.
The crucible shown in Figures 1 and 2 has the advantage of being easily
removable. Its material may of course be of other stone.
The heating receptacle or shell B may be used without the crucible for many
metal working and other operations. Thus, as shown in Figure 3 a tube G may be
inserted through one side of the insulating strip B2 for allowing the introduction
of bars of metal to the interior of the said receptacle. The ends of this tube may
be closed by doors and it may then be used as a muffle for baking porcelain and
similar uses.
In any case the current passes from one of the sections B or B' to the other
through the graphite filling E, generating so much heat in the said sections and,
both directly and by conduction from the sections, in the filling aforesaid, as to
heat the crucible and its contents intensely with the usual results; or similarly to
heat the rods or muffle exposed to such action.
The copper plates C are of such area that the discharge of electricity is from the
greater part of one of the sections aforesaid and to a corresponding part of the
other, effectually heating the said sections and the intervening graphite filling.
Having thus described my invention, what I claim as new and desire to secure
by Letters Patent is :-
First. A heating receptacle for crucibles and other articles and substances
consisting of the conducting and sections B B of relatively high resistance having
electrical circuit connections in combination with the interposed U-shaped insulating
strip B and the filling of pulverized conducting material substantially as set forth.
Second. A heating receptacle for crucibles and other articles and substances,
the said receptacle being composed of two sections of refractory heating material
of electrically high resistance and an interposed strip of insulating material and
provided with a filling of pulverized graphite or similar substance in combination
with electrical circuit connections to the said sections substantially as set forth.
Third. The end sections B' B2 of fire brick and graphite mixed in combination
with the interposed insulating material B³ the conducting plates imbedded in the
said sections, and electrical connections for the said plates, the receptacle which is
composed of the said sections and interposed insulating material being adapted to
contain a crucible or similar article substantially as set forth.
Fourth. A heating receptacle provided with a filling of pulverized graphite or
similar substance, and consisting of two sections of electrically conducting material
and an interposed insulating strip in combination with an enclosed crucible attached
to and removable with the said strip and the electrical circuit connections to the
said sections substantially as set forth.
Fifth. A hollow heating receptacle or electrical forge consisting of two con
ducting sections of high electrical resistance and interposed insulating material, in
combination with broad plates imbedded in the said sections and presenting a
considerable surface for the clectrical discharge, and the necessary circuit con
nections for these conducting plates substantially as set forth.
SM1 1002
Signed in the presence of :
EDWIN W. PIERCE.
PELATIAH R. TRIPP.
WILLIS MITCHELL.