IMPROVEMENTS IN MAKING STEEL AND RELATING TO BLAST FURNACES AND STEEL MAKING FURNACES
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by John Bromilow at the Office
of the Commissioners of Patents, with his Petition, on the 3rd
December 1875.
I, JOHN BROMILOW, Manager of Steel Furnaces, Newton, in the
County of Lanark, North Britain, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN MAKING STEEL AND RELATING TO BLAST
FURNACES AND STEEL MAKING FURNACES," to be as follows, that is to say :-
This Invention relates to the making of steel in a direct and
economical manner, and consists partly of an improved mode of utilizing
blast furnace gases, and gases from coke ovens or retorts; and partly of
improved modes of constructing and working, refining, or steel making
furnaces.
In carrying out the first part of the Invention according to one
modification, a portion of the blast furnace gases is led by one flue or
set of flues into a mixing chamber, and gases given off in making coke
are led by another flue or set of flues into the same mixing chamber.
The proportions of each kind of gas are regulated by valves, and the
resulting mixture is led to and used in the steel making furnace just as

page_text: at present the gases are from the gas producers, the steel making
furnace being in general construction and action of the kind known as
Siemens' regenerative furnace. In this way the too dilute and in-
sufficiently combustible quality of the blast furnace gases on the one
hand, and the too strong and too combustible nature of the coal gases
on the other hand correct each other, and the combination produces a
very suitable and inexpensive gas for the steel making furnace. Another
portion of the gases is used for heating the coke ovens or retorts, being
burned with the aid of the necessary air in flues surrounding the
ovens or retorts. The coke is of course required in the blast furnace for
smelting the particular iron ore used for making the steel.
The essential feature of the first part of the Invention is the enriching
of the comparatively poor blast furnace gases to make them available in
the steel making furnace, and this enriching may be effected by the
admixture of other gases as herein-before described, or by passing the
blast furnace gases in contact with the heated coal or coke in the ovens
or retorts, or in apparatus more or less like gas producers, in order that
the carbonic acid in the gases may be wholly or partially converted
into carbonic oxide.
In carrying out the second part of the Invention the reverberatory or
melting chamber of the furnace is constructed with the roof inclining
from each end downwards to the middle, and the ports of the air flues
which are made nearer the roof than the gas flues, are made with
considerable lengths of flue inclining downwards towards the middle of
the chamber so as to give direction to the currents of air. In a similar
way the ports of the gas flues are shaped to direct the gas currents so as
to be parallel to and separate from the air currents, and so that the two
currents may not completely combine until they reach or nearly reach
the middle of the chamber at which part it is intended the most intense
combustion shall take place. These improvements are expected to admit
of a furnace large enough to deal with fourteen tons of metal at one
charge being constructed and satisfactorily worked, whereas heretofore
a furnace for ten tons has been considered the largest workable size.
It is an object of the Invention to make one steel making furnace use
all the cast iron produced by one blast furnace, although if found more
convenient two or more steel making furnaces may be worked in
connection with one blast furnace. The steel making furnace is con-

page_text: structed beside the blast furnace, and with provision for running the
melted iron directly from the latter to the former so as to save the cost
of fuel for remelting; and before running each charge of melted iron into
the steel making furnace, the melting chamber of the latter is heated to
a temperature at least equal to, and by preference higher than that of
the iron, so that the refining and boiling or decarbonising process may
commence without loss of time. It may also be desirable to put the
fluxing materials in the chamber before hand, so that the melted iron
may be at one protected.
By these arrangements the very considerable proportion of time
hitherto generally required for melting and heating the iron will be
saved, and the furnace will be able to deal with many more charges of
iron in a given time.