IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES FOR MELTING METALS IN CRUCIBLES, AND ALSO IN THE CONSTRUCTION OF CRUCIBLES
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by Theodore Anthony Rochussen at
the Office of the Commissioners of Patents, with his Petition, on the
21st September 1864.
I, THEODORE ANTHONY ROCHUSSEN, of No. 9, Friday Street, Cheapside, in
the City of London, do hereby declare the nature of the Invention for
"IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES FOR MELTING METALS IN
CRUCIBLES, AND ALSO IN THE CONSTRUCTION OF CRUCIBLES," to be as follows:-
In constructing furnaces for melting metals in crucibles the furnace is
composed of two concentric cylinders of wrought iron closed at the bottom,
the inner cylinder being lined with fire-clay. In the centre of the inner
cylinder is placed the crucible containing the metal to be melted, and
around it the coke or other fuel used. The furnace is supported by two
trunnions resting on suitable bearings, one or it may be both of these trun-
nions is made hollow for the purpose of admitting blast into the hollow space
between the cylinders, thus absorbing the heat radiating from the exterior of
the furnace. Openings or tuyeres are made into the side of the inner cylinder
near its bottom, which are formed in such a manner as to carry the blast in
the direction of a tangent to the crucible containing the metal to be melted.
The leading the blast in this direction prevents the burning of the crucible by
heat impinging upon one particular spot, and also ensures a complete distri-
bution of the blast and consequently equal combustion of the fuel. The
Furnace is provided with a moveable top lined with fire-clay; the top is made
n the form of a truncated cone, and is open at the top for the purpose of

page_text: allowing the products of combustion to pass away. The crucible is also formed
with a conical moveable top, and the opening at the summit of the moveable
top is covered with a lid. By forming the crucible in this manner the charge
of metal in the crucible may be piled up to the top of the cover, so that as the
charge melts the contents sink down and fill the crucible. When the contents
of the crucible have been melted the blast is shut off by means of a valve in
the trunnion or other suitable position, the cover is then removed from the
furnace and the upper part of the crucible is gently nipped by a pair of tongs,
the opposite ends of the tongs are connected by suitable fastenings to opposite
sides of the top of the furnace, and so hold the crucible in its place. Each shank
of the tongs has attached to it a semicircular plate of iron, these plates cover
entirely the top of the furnace, and so prevent the escape of heat, and the work-
man being incommoded thereby. After the upper part of the crucible has been
thus secured the furnace is gently turned on its trunnions by means of a lever
handle attached to it and the contents of the crucible emptied into a mould or
receiver; the crucible is by this means emptied of its contents without moving
the crucible from the furnace. In place of the furnace being tilted by.a lever,
it may be tilted by a cog wheel on one of its trunnions or by other suitable
When the crucible has been emptied the furnace is turned back into
its original position, the crucible is again charged and its cover replaced and
filled, the cover is then put on the furnace and the fresh charge is melted.
As the crucible is emptied of its contents without moving the crucible
from the furnace the charges of metal will be melted. quicker than in the
ordinary furnaces, as there will be but little loss of heat from the furnace
or from the crucible whilst emptying it of melted metal; much larger crucibles
may also be used than those now employed, as. the crucibles have not to be
lifted or moved from the furnace by workmen as heretofore. Two or
more crucibles may if desired be contained in a single. furnace by making the
furnace oblong in horizontal section, and when large castings are required to
be produced a number of furnaces constructed as above described may be ranged
side by side either in a straight line or around a pit, and the mould or receiver
be placed on a truck moving on a tramway to collect successively the contents
of the crucibles. Crucibles constructed as herein-before described may be
.used with other descriptions of melting furnaces.
means.