IMPROVEMENTS IN SMELTING IRON AND STEEL AND IN APPARATUS AND FURNACES EMPLOYED IN CONNECTION THEREWITH
Year: 1869

page_text: LETTERS PATENT to Charles William Siemens, of No. 3, Great George
Street, Westminster, in the County of Middlesex, for the Invention
of "IMPROVEMENTS IN SMELTING IRON AND STEEL AND IN APPARATUS AND
FURNACES EMPLOYED IN CONNECTION THEREWITH."
Scaled the 7th December 1870, and dated the 14th October 1869.
PROVISIONAL SPECIFICATION left by the said Charles William Siemens
at the Office of the Commissioners of Patents, with his Petition,
on the 14th October 1869.
I, CHARLES WILLIAM SIEMENS, of No. 3, Great George Street,
Westminster, in the County of Middlesex, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN SHELTING IRON AND STEEL AND
IN APPARATUS AND FURNACES EMPLOYED IN CONNECTION THEREWITH," to be as
follows:-
Letters Patent were granted to me, bearing date the 20th September
1800, No. 2113, for smelting cast iron or cast steel directly from the
orcs by charging the orc together with reducing agents and fluxes

page_text: through inclined hoppers into a melting furnace (by preference a
regenerative gas furnace), it being intended that the reduction of the
ores into metallic or spongy iron should take place during its descent.
In the Specification to the same Patent I advocated the use of ferro-
manganeso or spiegel eisen to rectify the quality of the metallic bath
towards the end of each operation.
In putting the process into practico certain difficulties presented
themselves in effecting a sufficient reduction of the ores before
reaching the melting hearth of the furnace, to overcome which I had
recourse to vertical reducing muffics or rotorts described in the Specifi-
cation to my Patent of 21st August 1867, No. 2395, and also to
horizontal rotating reducing muffles, as described in my Patent of 10th
June 1868, No. 1892.
My present Invention has reference in the first place to an improved
mode of introducing the reduced ore into the open hearth of the melting
furnace without on the one hand exposing the reduced ore to the
oxydizing action of the flame, and on the other hand without exposing
the reducing hoppers, retorts, or muffles to the extreme heat of the
melting furnace. For this purpose I do not discharge the reduced ore
directly into the melting furnace as heretofore, but into a chamber or
chambers arranged at the back or along the sides of the same, in which
chamber or chambers a reducing atmosphere is maintained by an influx
of reducing gases, although there exists an open communication between
the chamber and the furnace. The bottom surface of this chamber (or
chambers) inclines towards the hearth of the melting furnace upon
which the metallic bath is prepared, in order to facilitate the introduction
of the reduced orc into the bath when required by means of rabbles
introduced through a door or doors opposite to the melting chamber.
From this reduced orc chamber (or chambers) vertical or inclined
hoppers or retorts rise upward, into which the raw or calcined orc
together with the reducing and fluxing materials are charged from above,
by preference, in a heated condition, and around these hoppers or retorts
channels are provided through which flame is made to circulate. This
flame may be derived from the melting furnace, as described in my
Patent No. 2395 of 1867, but I prefer to introduce heated gases coming
from a gas producer situated at a lower level, such as I have described in
my Patents Nos. 101 of 1801, and 3018 of 1864, but without passing
the gas previously through cooling tubes, and I introduce atmospheric
air which has been previously heated by being conducted over the roof

page_text: of the melting furnace, a double arch or moveable cover being formed
over the melting furnace to confine the air while being heated. This
cover I prefer to construct of metal with a brick lining fixed to its
under side, and I provide the same with hooks and lifting arrangements
for raising it when the furnace roof has to be repaired. The ore reducing
hoppers or retorts may with advantage be built up of fire-brick slabs,
and I prefer to construct them in the form of vertical blocks or clusters
bound with iron and containing several separate retorts or hoppers with
fire spaces between them, each hopper or retort containing, by preference
at regular intervals horizontal slabs or steps forming a zig-zag passage
for the ore, openings or doors being provided in the sides to push tho
ore from time to time from one step on to the next. The openings left
by these slabs or horizontal partitions may be closed occasionally by
covering plates or slides to admit of cach division being filled entirely
with ore. Or the arrangement of the apparatus may be so modified that
the ore is reduced in a separate block of retorts heated by a regenerativo
gas furnace, as described with reference to the reduction of zinc ores in
my Patent No. 1575 of 1869, by conveying the ores so separately reduced
to the melting furnace in closed receivers while still in a heated condition
by means of properly constructed tramroads or cranes.
If a rotating
ore reducing muffle is used I modify the arrangement of the same from
the plan described in my Patent No. 1892 of 1868, by not discharging
its contents directly into the melting furnace through the furnace roof,
but into the reduced ore chamber or chambers before mentioned. I also
prevent access to the reduced ore of the flame in the melting furnace by
closing all communication between the interior of the reducing muffle
and the fire flues or channels in the lining thereof, and by introducing the
gases for heating the muffle through separated orifices from without, care
being taken that both the combustible gases and atmospheric air enter
the fire flues within the lining in a heated condition. I further connect
the rotating calcining apparatus described in my Patent No. 1575 of
1869 with the reducing muffle, so that the hot calcined ores which may
be already partially reduced in the calciner descend directly into tho
reducing muffic, and I provide a separate feeding hopper for the intro-
duction of charcoal or other reducing agent, and of fluxing materials
which will become mixed with the heated ore within the muffle by its
rotation.
rotation.
The above described improved processos and arrangements of apparatus
are equally applicable for treating iron in a divided state which may

page_text: have been partially or wholly oxidized for the purpose of its purification
instead of or in conjunction with orc. Or cast-iron in a divided stato
may be used in lieu of other reducing agents with the ore. The melting
furnace which I employ is similar to those I have described in my
Patents above referred to, but I improvo the arrangement for mixing the
heated combustible gases and the heated air arising from the regenerators
by raising the vertical air ports very nearly to the roof of the furnace,
and by bringing the side walls of the flues forward towards the heated
chamber in a convergent manner until they meet. By this arrangement
the gas is introduced into the heated chamber below the air through
channels increasing in width towards the furnace, where it is met by the
air passing in in diverse directions, effecting its thorough combustion
whilo traversing the heated chamber, the uncombined air being at the
same time prevented from coming into contact with the metal on the
bed of the furnace. The quality of the metal produced by the before
described processes may be varied between the limits of mild cast steel
and cast iron without changing the apparatus in any material point. In
arranging steel works I place several melting furnaces side by side with
their fronts or tapping holes facing the foundry. Or I place two such
rows opposite each other with the foundry between them. From cach
centre of furnace or tapping hole a trench extends at right angles to the
line of furnaces into a wider and deeper trench running through the
middle of the foundry parallel with the line of furnaces. A line of rails
is laid upon the edges of the cross trenclics and across the central trench
upon girders, which line of rails carries the ladle carriages by which a
ladle when suitably lined and heated may be drawn up close to the
tapping hole to receive a charge of steel, and be moved by a wheel and
pinion or other agency over the central trench. A line of rails at the
bottom of this latter carries suitable trucks upon which the moulds to
receive the fluid metal are arranged. By opening the stopper in the
bottom of the ladle theso moulds are filled, and the truck upon which
they are mounted is moved out of the founday to a crane, or into an
annealing stove if the castings are not to be hammered or rolled. By
this general arrangement tho preparation of the moulds and the removal
of the cast ingots or castings is greatly facilitated.