AN IMPROVED PROCESS AND APPARATUS FOR THE DIRECT CONVERSION OF IRON ORES AND METALLIC IRON
Year: 1877

page_text: LETTERS PATENT to Bristow Hunt, of Serle Street, Lincoln's Inn, in the
County of Middlesex, Gentleman, for the Invention of "AN IMPROVED PROCESS
AND APPARATUS FOR THE DIRECT CONVERSION OF IRON ORES AND METALLIC
IRON." A communication from abroad by Mark John Hamilton, of the City
of St. Louis, State of Missouri, in the United States of America.
PROVISIONAL SPECIFICATION filed by the said Bristow Hunt at the Office of
the Commissioners of Patents on the 6th September 1877.
BRISTOW HUNT, of Serle Street, Lincoln's Inn, in the County of Middlesex,
Gentleman. "AN IMPROVED PROCESS AND APPARATUS FOR THE DIRECT CON-
VERSION OF IRON ORES AND METALLIC IRON. (A communication from abroad by
Mark John Hamilton, of the City of St. Louis, State of Missouri, in the United
States of America.)
The object of this Invention is to extend the field of steel manufacture by
utilizing low grades of pig metal, and such rich ores as are now discarded in the
manufacture of steel on account of the large per-centage of phosphorous and sulphur
which they contain, and also to economize production by substituting a cheap and
direct process for the expensive and indirect processes heretofore employed.
For the better understanding of the Invention it may be advisable to introduce
here the following brief description of what is known as the pneumatic process:-
Highly carburized pig metal is melted in a cupola, and is run thence into the
converter, which has been brought into a nearly horizontal position, but with the
throat so depressed that the liquid metal will not rise as high as the holes in the
tuyeres. The blast is then turned on and the converter brought into a vertical
position. As soon as the oxygen of the blast comes in contact with the molten mass
the silicon is oxydized, and, combining with a portion of the iron, forms a silicate of
the protoxide of iron. The carbon is next attacked by the oxygen and passes out
D

page_text: When
at the throat in a gaseous form. The blast is kept up until the metal is completely
decarburized, or in fact brought back to the same condition it was in the blast
furnace after the first change or deoxidation took place, with the exception that it
was then associated with the gangue of the ore from which it is now free.
the iron is thus decarburized the converter is brought into the same position in which
it was when the molten pig iron was run into it from the cupola. The blast is then
cut off and spiegeleisen or some other highly carburized iron in the molten state, and
in a determined proportion, is poured into it. In a few moments the carbon of
the spiegeleisen is disseminated through the mass and the iron is converted into steel.
The changes which the ore undergoes in its transition from ore to steel may be
described as follows:-The ore is deoxidized to metallic iron in the upper part of
the blast furnace, after which it is carburized, fused, and run into pigs. These
pigs are again melted in a cupola and run into the converter in which the
molten mass is completely decarburized to malleable iron and finally recarburized
to steel
The following is a description of the improved direct process and of the mechanical
construction of the apparatus connected therewith.
The converter is provided with hollow trunnions adapted to suitable bearings, and
one of which connects an annular pipe (1) with the gas puritier, described herein-after,
through other pipes (2,) (3,) and the other of which connects another annular pipe
(4) through other pipes 5, 6, with the blast main, also to referred to herein-after.
The lower end of the pipe 5 is arranged to fit snugly, but slide freely in the
upper branch of an elbow pipe 7, the lower branch of which is firmly secured to the
pipe 4.
In like manner the lower end of the pipe 3 is adapted to the upper
branch of the elbow pipe 8, the lower branch of which is firmly fixed in the
pipe 1.
The pipes 2, 6, are furnished with cocks or valves which are preferably operated
by water power in the manner explained herein-after. A series of branch pipes 9
conduct the air from the blast pipe 4 into chambers, and a series of branch pipes 10
conduct the gases from the pipe 1 into the same chambers. These chambers are
within boxes firmly fixed in a plate at the bottom of the converter, the boxes being
expanded above the plate in the shape of hollow truncated cones, which form
sockets into which the tuyeres are fitted with luted gas-tight joints. This plute is
strengthened by substantial radial ribs, and forms the top of the cylindrical chest to
which the pipes 4, 1, are secured, and which is connected to the converter by screw
bolts, keys, or otherwise.
The space between the plate and the bottom of the converter is filled with plastic
clay or some such material in order that no leakage can exist between the
tuyeres and the sockets in which they are luted. This is accomplished by filling the
space surrounding the sockets with the desired material, and allowing its upper
surface to project a little above them, and then forcing the chest up into its place by
hydraulic or other pressure, so as to force the plastic material into every crevice, or
it may be accomplished by fixing the chest in place, and then forcing the plastic
material through holes in its side above the plate by machines similar to those used
for making tile pipes.
The pipes 9, 10, are connected to branches by screw joints, and are also connected
to the boxes in like manner, and have traps fitted with gas-tight screw stoppers;
these traps are for the purpose of removing any pieces too large to be blown
through the tuyeres that may have found access to these pipes. When renewing
the tuyeres the traps must be kept open until the chest is firmly secured in place,
after which the stoppers will be screwed tightly in the said traps.
The carbon receiver is a gas-tight vessel of any shape provided that its lower end
is made tapering and terminates in a pipe having a cock which serves to regulate
the flow of the powdered carbon, the pipe ending in a slightly conical nozzle which
opens into the gas blast pipe 2, and in the direction of the blast, so that the current
of the passing gases will cause a partial vacuum at its open end. A pipe 11 forms
a communication between the gas blast pipe and the upper part of the interior of

page_text: the carbon receiver, and ends in a perforated nozzle, the blast being cut off when
necessary by a cock. On the other side of the converter, in connection with the air
blast pipe 6, is a flux receiver similar in every respect and similarly situated to the
carbon receiver, above described.
The above described converter can be revolved on its axis for purposes explained
herein-after.
In describing the permanent converter it will be necessary to refer minutely to those
parts only which differ from those of the movable converter described above.
The fixed converter is of a somewhat different form to that of the movable
converter; its outer shell is made of wrought iron plates strengthened internally by
ribs of I iron, which serve to keep the lining which is rammed between them
firmly in place when dried and hardened. A tuyere box made of wrought-
iron plates is connected to the shell preferably by angle irons rivetted both to the
plates and to the shell.
The tuyere box cover in which the said boxes containing the chambers are firmly
fixed, fits closely but not tightly into the tuyere box, and is kept in place by clamp
screws working in clamp bars. These clamp bars pass through holes in the projections
on the upper and lower sides of the tuyere box, and are so attached to the tuyere
box cover by the clamp screws. The space between the tuyere box cover and the
side of the converter is filled with plastic clay or some other suitable material to
prevent leakage between the tuyeres and the sockets in which they are luted.
The pipes 4, 1, rest on brackets attached to the shell, and are retained by clasps or
keys so arranged as to admit of their easy removal when necessary. These pipes
may be so connected with the said boxes that the tuyere box cover may be removed
when renewing the tuyeres without disturbing them by making the pipe connecting
the branch pipes 9, 10, with the chambers in two parts, and connecting by
screw collars above the level of the tuyere box.
The ends of the pipes 4, 1, connecting with the blast pipes are bent at right
angles to them, and are arranged to fit snugly, but slide freely in the short
pipes 7, 8, which are firmly fixed to the end of the converter.
When the converter is large, there should be two tap holes similar to those of a
blast furnace, and stopped in a similar manner, but having a plate to cover
over them, wedged to the end of the converter, so that no accident may occur
by the forcing out of the stoppers during the operation.
The tuyeres are arranged alternately, that is, a tuyere in one side is opposite the
space between two tuyeres on the other side, and all are placed a few inches
above the bottom, which slopes both ways from the centre down to the tap
holes in order to facilitate the flow of the cinder or slag after the metal is
tapped off, and thereby prevent any of it remaining from one operation to another.
The gases escape from the converter through an opening into the external air
or into a chamber in which the ore or blast can be heated. The converter is
charged through apertures which are closed with fire-brick stoppers properly
luted and fastened before the blast is let on. The stoppers are connected with
a balance weight and lever, having a horizontal as well as a vertical motion, so
that they may be removed without difficulty, and placed in a position where they
will not interfere with the charging operations.
When in place they are secured by a clamp bar and wedges similar to those used
in gas works to secure the covers of the retorts. A funnel may be used in charging
to prevent such wear of the lining as might interfere with the proper fitting of the
stoppers.
In another modification the movable converter is made with the tuyers in the
sides, and like those above described (over which it possesses some advantages), its
shell is made of wrought-iron plates lined inside with refractory material rammed
in between interior ribs of H iron. This converter has two cast-iron rings secured
to the shell, and connected to inner rings by radial arms, and to which inner rings
are secured cog wheels through which motion is given to the converter. Outer
rings rest on antifriction rollers on standards secured to a suitable foundation.

page_text: The pipes 3, 5, are fixed to the shell of the converter, as are also the pipes 7, 8, into
which the elbows of the movable pipes 4, 1, are arranged to slide. To the ends of
the pipes 3, 5, (terminating in the centres of the said cast-iron rings) are bolted short
and slightly conical pipes, into which the elbows of the pipes 2, 6, fit. These short
conical pipes must be very carefully centred, so that when the converter moves
around its axis of revolution, the joints between them and the pipes 2, 6, will work
smoothly and remain gas-tight. All the other parts are similar to those herein-
before described and will not require description.
The apparatus used in operating the valves in the pipes 2, 6, and regulating the
admission of the gas and air blasts to the tuyeres is as follows:-One end of an arm
is secured to the spindle of the valve of the pipe 2, and the other end is connected
by a rod to the piston rod of a piston adapted to a cylinder which communicates
with another cylinder by pipes 12, 13, which pass from the converter under the floor
to the operator's stand, and have their horizontal parts connected with the waste
water reservoir by pipes in which are cocks emptying them when necessary. Imme-
diately under the stand, the pipes 12, 13, are connected with a supply pipe 14 by a
horizontal pipe 15, having in it cocks for cutting off both pipes from the supply pipe,
and for cutting off the connection between the pipes themselves. The piston in the
second cylinder is connected with a piston in a third cylinder by a common piston
rod, the upper end of which carries an index arm arranged so as to show
exactly the extent of the area of the opening of the valve of the pipe 2, so that the
flow of the gas may be regulated with certainty. The third cylinder is connected
with the supply pipe through a cock and connecting pipes.
In the supply pipe is a cock for purposes herein-after stated, and there is a
waste water pipe 16 leading to the waste water reservoir.
Apparatus similar in every respect to that described is used in connection with
the air valve pipe 6, so as to regulate the flow of the atmospheric air to the
tuyeres.
The third cylinder connected with the gas valve, and the similar cylinder
connected with the air valve, are so placed that both can be worked at the same
time by a boy standing between them.
When commencing operations, the gas valve is shut and clamped in that
position, the piston of the first cylinder being at the bottom thereof, and consequently
the other pistons at the tops of their respective cylinders. The cock above referred
to in the supply pipe, and the above referred to emptying cocks being closed, the
cocks in the pipe 15 are opened, and the water from the supply pipe allowed to flow
into and fill the first and second cylinders, after which the valve is unclamped and
the cocks in the pipe 15 are closed, and remain so during the subsequent operations.
In order to open the valve it is only necessary to gradually open the cock in the
supply pipe, and then turn another cock above referred to slowly, so as to let the
water flow above the piston in the third cylinder and press it down, and therefore
depress the piston in the second cylinder connected with it by the common piston
rod. By this means the water below the piston in the second cylinder is forced
through the pipe 12 into the first cylinder, and the piston in it pressed upward,
thereby displacing the water above the piston, and forcing it to flow back through the
pipe 13, and fill the vacant space caused by the descending piston in the second
cylinder. A reverse motion of the valve will of course close the gas valve. When
it is necessary that the valve shall only be partially opened, the index arm is brought
to the desired position, and the cock in the supply pipe closed so as to remove
the pressure from the piston in the third cylinder, and thus cause it to remain
at rest.
The gas purifier has an external shell of wrought iron and an internal lining of
fire brick for the purpose of preventing as far as possible the loss of heat by radia-
tion. The purifier is cylindrical and is divided into two parts by an inverted
conical bottom, the lower part being the cinder trap into which pieces of the fuel
too large to float in the gaseous atmosphere in the purifier will fall.
Attached to the bottom is a short pipe having a cock or valve through which

page_text: communication is formed between the upper and lower divisions. The rod by which
the cock is operated passes through a stuffing box. There is a pipe which leads from
the cinder trap to the open air, and has a cock, and there are man holes for allowing
of repairs and of the removal of the cinders from the cinder trap, both man holes
being furnished with suitable detachable covers. The cock of the short pipe is always
closed before the cock of the open pipe is opened, and vice versa.
The generator is a cylindrical vessel made of wrought-iron plates and lined with
fire-brick and has an ash pit. On the top of the vessel is a feeding device of which a
piston is adapted to a cylinder and operated either by steam or water power. The
rod of this piston is connected to a piston in a lower or charging cylinder in which
the fuel is placed before it is fed into the generator. The fuel is charged into the
lower cylinder through an aperture. A pipe connects the interior of a gas-tight
valve box with the cylinder, and has a cock. Another pipe connects a hollow
truncated cone with the open air, and has a cock. A poker passes through a gas-
tight stuffing box into the lower part of the hollow cone for loosening the fuel in
case it should become jammed. These cylinders and their attachments are supported
by girders which relieve the crown of the generator from pressure, and also support
the floor on which the men stand when at work.
The valve box contains a valve and has a double top, bottom, and sides so as to
form spaces through which water can circulate freely during the whole time that the
fuel in the generator is ignited, whether work is going on or not, in order to
the surfaces of the valve and seat.
preserve
Water may be supplied to the said spaces from an elevated reservoir, and may be
discharged from the spaces through suitable pipes, so that the valve box shall always
be in a comparatively cool condition.
The valve is hollow, as is also the valve rod, which passes through a stuffing box,
and is connected to any device for operating the valve by steam or water pressure.
A cold water pipe extends through the hollow valve rod to within a few inches
of the end of the valve, and an elastic tube connects with the pipe through the side
of the hollow valve rod, and conveys cold water to the valve. The water, after
cooling the valve, passes out through a space between the external surface of the
pipe and the internal surface of the hollow valve rod, and thence through a second
elastic tube similar to the tube on the opposite side of the hollow valve rod.
A circular pipe surrounds the upper part of the generator, and is supported on
brackets rivetted to the wrought-iron shell; it is connected with the interior of the
generator by openings, and also with the purifier by a pipe, having a cock through
which the gas generated is conveyed. Another circular pipe surrounds the generator,
and communicates with its interior through the pipes or tuyeres, and through
another pipe with the main blast pipe. In this other pipe is a cock for cutting off
the blast from the generator. Another pipe connects the blast pipe with the ash-
pit, and has a cock. Another pipe leads from the ash-pit to the open air, and has a
cock. A cast-iron-ring has two cold-water supply pipes and two hot-water discharge
pipes in order that the water may not become overheated. This ring is supported
by girders, which rest on the brick lining of the ash-pit, and may be made hollow
and have a stream of cold water passed through them. The grate bars are also
supported by these girders, and are supplied with streams of cold water through
pipes. A valve slightly wedge-shaped is fitted to the ring, and has a cold-water
tube supplied through an elastic tube, and a warm-water space connected with an
elastic discharge tube.
The hollow valve rod has a screw thread cut on its external surface, and adapted
to a screw on the internal surface of the nave of a wheel, which is tight against a
bracket plate, and is kept firmly in its place by a follower let into the nave. It is
evident, therefore, that by revolving the wheel the valve rod will be moved horizon-
tally in the required direction, and the wedge-shaped valve shut or opened, as
desired. This valve is always open except when it is found necessary to clean out
the ash-pit. As pieces of incombustible material may be too large to fall through
the grate bars, a poker is employed to remove them. This poker has a lateral but

page_text: not a vertical motion, and passes unrougu & monow stopper, WHICH
its vertical axis in a case rivetted to the wrought-iron shell. The stopper is hollow,
being cylindrical inside and slightly conical on its outer surface, fitting exactly into
its case.
The central hollow of the stopper forms the stuffing box, which, like the
other stuffing boxes and joints connected with this apparatus subject to a high
temperature, is packed with asbestos in the form of paper or cloth, or other suitable
form. A small quantity of graphite is placed around and in contact with the
movable member, which in this case is the poker, to which the packing is pressed
closely. The incombustible material which falls through the grate bars is removed
from the ash-pit.
OPERATION.
After the lining in the generator has been dried, some of the above-mentioned
blast cocks are closed, but the top and bottom valves remain open as well as the
ash-pit door. The piston in the lower cylinder is raised above the upper edge of
the charging aperture in this cylinder. The lower part of the generator is filled up
to about the level of the tuyeres with small pieces of thoroughly dried wood through
the said aperture; coke or charcoal is then charged on to the wood through the
same aperture until the generator is filled, after which the fire is lighted at the
grate bars, and fed by an air draught through the ash-pit opening. As soon as the
fuel has been properly ignited the grate bars and ash-pit are cleaned out and this
opening closed. The top valve is now closed, as are also certain of the cocks, so as
to make the generator gas-tight. Another cock, above referred to, is then partially
opened, and a gentle air blast allowed to enter the fire through the pipe in connection
with the tuyeres until the gases in the generator have attained their maximum
pressure, after which this cock is fully opened. When it is necessary to supply fuel
to the fire after the gases in the generator have attained their maximum pressure,
the piston in the charging cylinder is raised above the charging aperture, and the
former filled to within a few inches of the lower edge of the said aperture with
fuel, which may be coke, coal, charcoal, or thoroughly dried wood; the piston is
then lowered on the fuel, in which position it cuts off all communication between
the space occupied by the fuel and the open air. Others of the said cocks are now
closed and opened to allow the gases in the generator to flow into the cylinder
below the piston, and establish an equilibrium of pressure above and below the top
valve, which is then drawn back, and the fuel is allowed to drop into the generator.
These cocks are then reversed, and the piston lowered to the junction of the cylinder
with the hollow cone; the valve is then pushed forward, and the gases in the
hollow cone are allowed to pass into the open air. The equilibrium being thus
destroyed the valve is forced against its seat on the under side of the cover of the
valve box by the gases in the generator. The piston is again raised above the
aperture and the charging continued as before. If the fuel should jam in the
lower part of the cone it can be loosened by the operating poker or other equivalent
device.
When it is necessary to remove the ashes from the ash-pit one of the cocks is
closed, and the wedge-shaped slide valve pushed forward by turning the said wheel
until it is tightly pressed against a ring by being jammed between it and the grate
bars, which slope at the same angle as the lower side of the wedge-shaped valve,
and thus cause its upper surface to remain horizontal. A cock is now opened, and
the gases in the ash-pit allowed to flow into the open air until the pressure inside
and out are the same or nearly so; another cock is then opened and the remainder
of the gas removed by the atmospheric air flowing through some of the pipes.
Care must be taken to remove all the gases from the ash-pit before opening its door,
so as to avoid the explosion that would take place if any ignited matter chanced to
be in the ash-pit with the gases at the time. As soon as all the gases are thus
removed one of the cocks is closed, the door opened, and the ash-pit cleaned out,
after which another cock is closed and the door replaced as before. If the tuyeres

page_text: enter below instead of above the grate bars, one of the pipes will be dispensed with
and the door removed as soon as the lower valve is closed, and the pressure lowered
to that of the atmosphere by opening a cock.
The purifier is prepared by luting and firmly fixing the covers of the man holes,
closing one cock and opening another. When it is necessary to remove the cinders
from the trap the last referred to cock is closed and the other opened, so as to allow
the gases in the trap to flow into the open air until the pressure inside is equal to
the pressure of the atmosphere; the man hole is then opened and the cinders
removed, after which the cover is replaced as before, and the cocks reversed.
When coke or charcoal is used for fuel the gases which pass from the generator
into the purifier are nitrogen and carbonic oxide, but when coal is used there will
be an admixture of hydrocarbons, which are formed by distillation in the upper
part of the generator. The formation of the other gases may be described as
follows:-
Atmospheric air is composed of two gases, namely, nitrogen and oxygen, the
latter of which combines with carbon at a high temperature, setting the nitrogen
free. It forms two combinations with carbon, vizt., one equivalent of carbon and
one of oxygen forming carbonic oxide, and one equivalent of carbon to two of
oxygen forming carbonic acid. These gases pass very readily from one to the
other at a high temperature, according to the excess of oxygen or carbon, hence it
is evident that at the point of the tuyeres in the generator, where the oxygen of
the blast is in excess, carbonic acid must always be formed, and also that as this
gas passes through the incandescent fuel it will combine with an additional
equivalent of carbon and become carbonic oxide, in which form it will pass mixed
with nitrogen, and also with hydrocarbons when coal is the fuel employed, into the
purifier, and thence through pipes 23 into the chambers under the tuyeres in the
converter.
The term carbonic oxide will be understood in this Specification to mean
carbonic oxide with its associated gas or gases as they pass into the converter from
the generator.
When charging the converter the bottom is first covered with a thin layer of
ignited fuel, and on this is placed the ore to be converted. It must be washed
and broken to about the size of road metal, and spread as evenly as possible over
the ignited fuel. A very gentle air blast is then put on through the blast pipe 6,
so as to cause the fuel in the bottom of the converter to burn to flame. One of the
said cocks is then gradually opened, permitting streams or jets of carbonic oxide
gas to flow through the pipes 10, and meet similar streams of atmospheric air
through the pipes 9 in the chambers, where they commingle and pass through the
tuyeres in this mixed condition. On coming in contact with the flame in the bottom
of the converter the carbonic oxide burns to carbonic acid, and generates an
intense heat sufficient to melt even malleable iron, and by this heat the ore is fused.
Instead of placing fuel in the bottom of the converter the gases may be ignited at
the mouth of the same. After fusion is completed the atmospheric air is cut off by
closing a cock, and the flow of carbonic oxide gas through the molten mass con-
tinued until the ore is reduced, the gases formed escaping through the throat.
In order to facilitate this part of the operation certain of the cocks are opened to
permit the powdered carbon previously placed in the receiver to pass out through
its nozzle, and, borne on by the current of the gases, to pass up with it into the
molten mass, and combine with the oxygen in it, thereby materially assisting in the
deoxidation of the ore. This powdered carbon may be pulverized coke, charcoal,
coal dust, or any other suitable carbonaceous matter. The ore thus reduced may
now be fluxed by such agents in a powdered or gaseous state as may be found most
desirable. The receiver, similar and similarly situated to the carbon receiver, but
on the opposite side of the converter, is used for the powdered or gaseous flux,
which is carried through the tuyeres, and thence upward through the molten mass,
usually by the air blast. If, however, the ore contains a considerable per-centage
of foreign matter, such as silica, or the like, the carbonic oxide gas should be used

page_text: as the vehicle or means by which the flux is carried through the molten mass,
using the carbon receiver on the same side for the powdered flux. If air be used,
when the quantity of the impurities is large, there will be an unnecessary wasto
of metal by the formation of silicates; on the other hand, if the gases are made the
vehicle, when the quantity of the impurities is small, there will be a waste of fuel
in generating the gas for that purpose. An analysis of the ore will determine
which should be used.
From one cause or another the temperature of the bath may be somewhat
reduced below the intense heat required to keep the malleable iron in that state
of fusion necessary for the subsequent operations. In this case the air and gas
must be used at the same time, in order to restore the lost heat and the air blast
employed to carry the flux from the flux receiver proper to the tuyeres, whence it
will be carried upward through the molten mass by the carbonic acid gas formed at
their inner ends. It will be observed that the mechanical arrangements are such
as to meet all these cases.
Under certain circumstances it will be found desirable to mix limestone broken
into small pieces with the ore when charging the converter. The ore having been
thus reduced and fluxed the converter is turned sufficiently to allow the cinder or
slag to flow into the ladle or other vessel prepared for that purpose. After the
slag has been removed the converter is brought again into the vertical position (the
full pressure of the air or gas being put on just before it begins to move), and a
stream of atmospheric air or carbonic acid gas sent through the metal to remove
any carbon that may have been in excess of that required for reduction, so that
the proper quantity of carbonic oxide gas and powdered carbon required to cause
the desired degree of hardness may be accurately determined. When thus purified
the metal can be carburized to any degree of hardness by cutting off the atmospheric
air and sending through the molten metal a determined weight of powdered
carbon from the re-filled carbon receiver in streams or jets of carbonic oxide gas
flowing for a definite time. As soon as this last operation is completed the con-
verter is turned, the gas cut off, and the metal poured into ladles ready for casting
into ingots or moulds of any required shape.
When it is desired to change scrap iron or pig metal into steel it must be broken
or cut into small pieces, and spread as evenly as possible on a thin layer of ignited
fuel in the bottom of the converter. The atmospheric air and carbonic oxide gas
are then turned on, as herein-before described, but in this case the carbonic oxide
gas should be in excess in the fusing flame, a part only being burnt to carbonic
acid gas so as to avoid the unnecessary waste that would otherwise be caused by
the oxidation of the metal. After fusion is completed the removal of the
impurities and the final carburization of the metal ore accomplished in the same
manner and by the same means employed in the case of metal made direct from 4
the ore.
If the ore or metal contain phosphorous or sulphur, and it is considered desirable
to use the carbonic oxide gas as the vehicle by which the regular flux is carried
through the molten mass, the agents, such as chlorine or chloride of sodium employed
for their removal, must be used after the fluxing of the other impurities is com- 4
pleted, and should be carried through the molten metal by atmospheric air or
carbonic acid gas; but if the regular flux is carried into the metal by either atmo-
spheric air or carbonic acid gas the agents used for the removal of the phosphorous
or sulphur may be mixed with it, and all the impurities acted on at the same time.
If gases are used as fluxes instead of powder for the removal of phosphorous or 5
sulphur they are put into a gas receiver similarly placed to the powder flux receiver,
and blown through the molten metal in a similar manner to that herein-before
described.
If steel is made by the ordinary process now employed, and it is only necessary
to remove the phosphorous or sulphur from the molten metal before carburization, 5
the generator and gas pipes can be dispensed with, the air pipes alone being
necessary.

page_text: Certain of the cocks in the converter must be gradually opened and shut when
the converter is in a vertical position, so that the pressure at the point of the
tuyeres may be constant.
When the permanent converter is employed the slag or cinder cannot be
removed until the iron is tapped off, on account of its floating on the molten
metal.
It must also be remarked that the flow of carbonic oxide gas must be continued
during the time that the iron and slag are running from the converter, and at a
pressure sufficient to prevent them from filling the holes in the tuyeres. The
metal is tapped off in exactly the same manner as the iron from the blast furnace,
and the tap hole stopped in the same manner, except that in this case there is the
additional security of the wedged cover over it.
With these exceptions the process is substantially the same as that herein-before
described.
The direct process may also be conducted as follows:-The ore can be melted in
a separate furnace, such as a reverberatory furnace, or any other suitable furnace and
poured into the converter in a liquid state, where it can be deoxidized, fluxed, and
carburized, as herein-before stated, or after deoxidation and fluxing are completed
and the cinder removed, the metal can be carburized in the manner now practised
by pouring into it either spiegeleisen or some other highly carburized iron previously
melted in a separate furnace or cupola.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Bristow Hunt in the Great Seal Patent Office on the 6th March
1878.
BRISTOW HUNT, of Serle Street, Lincoln's Inn, in the county of Middlesex,
Gentleman. "AN IMPROVED PROCESS AND APPARATUS FOR THE DIRECT CON-
VERSION OF IRON ORES AND METALLIC IRON." (A communication from abroad by
Mark John Hamilton, of the City of St. Louis, State of Missouri, in the United
States of America.)
The object of this Invention is to extend the field of steel manufacture by
utilizing low grades of pig metal and such rich ores as are now discarded in the
manufacture of steel on account of the large per-centage of phosphorous and sulphur
which they contain, and also to economize production by substituting a cheap and
direct process for the expensive and indirect processes heretofore employed.
For the better understanding of the Invention it may be advisable to introduce
here the following brief description of what is known as the pneumatic process:-
Highly carburized pig metal is melted in a cupola, and is run thence into the
converter, which has been brought into a nearly horizontal position, but with the
throat so depressed that the liquid metal will not rise as high as the holes in the
tuyeres. The blast is then turned on, and the converter brought into a vertical
position. As soon as the oxygen of the blast comes in contact with the molten
mass the silicon is oxydized, and combining with a portion of the iron forms a
silicate of the protoxide of iron. The carbon is next attacked by the oxygen and
passes out at the throat in a gaseous form. The blast is kept up until the metal is
completely decarburized, or in fact brought back to the same condition it was in
the blast furnace after the first charge or deoxydation took place, with the excep-
tion that it was then associated with the gangue of the ore from which it is now
free. When the iron is thus decarburized the converter is brought into the same
position in which it was when the molten pig iron was run into it from the cupola.
The blast is then cut off, and spiegeleisen or some other highly carburized iron in
the molten state, and in a determined proportion, is poured into it. In a few
moments the carbon of the spiegeleisen is disseminated through the mass, and the
iron is converted into steel.
The changes which the ore undergoes in its transition from ore to steel may be
described as follows:-The ore is deoxidized to metallic iron in the upper part of
the blast furnace, after which it is carburized, fused, and run into pigs. These pigs
are again melted in a cupola and run into the converter, in which the molten mass
is completely decarburized to malleable iron and finally re-carburized to steel.
The following is a description of the improved direct process, and of the mechanical
construction of the apparatus connected therewith.
Figure 1, Sheet 1 of the Drawings, is a vertical section of a converter having an
outer shell of wrought-iron plates, and an interior lining of the most refractory
materials obtainable; and Figure 2 is an under plan view thereof.
The converter is provided with hollow trunnions B1, B2, adapted to suitable
bearings, and one of which, B', connects an annular pipe Z with the gas purifier,
described herein-after, through other pipes K, Q, and the other of which, B2, connects
another annular pipe Y, through other pipes S, R, with the blast main, also referred
to herein-after.
The lower end of the pipe S is arranged to fit snugly, but slide freely, in the
upper branch of an elbow pipe X, the lower branch of which is firmly secured to
the pipe Y. In like manner the lower end of the pipe Q is adapted to the upper
branch of an elbow pipe W, the lower branch of which is firmly secured to the
pipe Z.
The pipes K, R, are furnished with cocks or valves, which are preferably operated
by water power in the manner explained herein-after. A series of branch pipes a

page_text: conduct the air from the blast pipe Y into chambers c, and a series of branch pipes b
conduct the gases from the pipe Z into the same chambers. These chambers are
within boxes c¹, firmly fixed in a plate x at the bottom of the converter, the boxes
being expanded above the plate in the shape of hollow truncated cones which form
sockets, into which the tuyers d are fitted with luted gas-tight joints. This plate x
is strengthened by substantial radial ribs a, see Figure 2, and forms the top of a
cylindrical chest P, to which the pipes Y, Z, are secured, and which is connected to
the converter by screw bolts, keys, or otherwise.
The space between the plate x and the bottom of the converter is filled with
plastic clay or some such material in order that no leakage can exist between the
tuyers d and the sockets in which they are luted. This is accomplished by filling
the space surrounding the sockets with the desired material, and allowing its upper
surface to project a little above them, and then forcing the chest P up into its place
by hydraulic or other pressure, so as to force the plastic material into every crevice;
or it may be accomplished by fixing the chest P in place, and then forcing the
plastic material through holes in its side above the plate by machines similar to
those used for making tile pipes.
The pipes a, b, are connected to branches a¹, b', by screw joints, and are also con-
nected to the boxes c' in like manner, and have traps a², 62, (fitted with gas-tight
screw stoppers) for removing any pieces too large to be blown through the tuyers
that may have found access to the pipes a, b. When renewing the tuyers the
traps must be kept open until the chest P is firmly secured in place, after which the
stoppers will be screwed tightly in the said traps.
The carbon receiver M is a gas-tight vessel of any shape provided that its lower
end is made tapering, as shown, and terminates in a pipe having a cock t, which
serves to regulate the flow of the powdered carbon, the pipe ending in a slightly
conical nozzle, which opens into the gas blast pipe K, and in the direction of the
blast, so that the current of the passing gases will cause a partial vacuum at its
open end v.
N is a pipe which forms a communication between the gas blast
pipe K and the upper part of the interior of the carbon receiver M, and ends in a
perforated nozzle N¹, the blast being cut off when necessary by a cock 8. On the
other side of the converter in connection with the air blast pipe R, is a flux receiver
S¹, similar in every respect, and similarly situated to the carbon receiver above
described. It is not necessary that the receivers should be in the exact position shown
on the Drawings, but the conical nozzle v must open in the direction of the current
of the blast passing through the pipe in which it is inserted.
The above described converter can be revolved on its axis for purposes explained
herein-after.
The permanent converter is illustrated in Sheet 2 of the Drawings, Figure 3
being a longitudinal vertical section; Figure 4, a side view; Figure 5, a transverse
vertical section; Figure 6, an end view; and Figures 7 and 8, enlarged detail
views.
In describing this part of the Invention it will be necessary to refer minutely to
those parts only which differ from those of the movable converter described above.
The parts which are similar in the two converters are marked and designated by
the same letters.
The fixed converter 0₁ is preferably of a different form to that of the movable
converter. Its outer shell is made of wrought-iron plates, strengthened internally
by ribs P of I iron, which serve to keep the lining t¹, which is rammed between
them, firmly in place when dried and hardened. A tuyer box x¹ made of wrought-
iron plates is connected to the shell, preferably by angle irons rivetted both to the
plates and to the shell.
The tuyer box plate or cover x, in which the boxes c¹ containing the chambers c
are firmly fixed, fits closely, but not tightly, into the tuyer box x¹, and is kept in place
by clamp screws ³, working in clamp bars x, as shown in Figure 7. These clamp
bars pass through holes in the projections on the upper and lower sides of the tuyer
box, as shown in the same Figure, and are so attached to the tuyer box cover by

page_text: the clamp screws. The space between the cover x and the side of the converter is
filled with plastic clay or some other suitable material to prevent leakage between
the tuyers and the sockets in which they are luted.
The pipes Y, Z, rest on brackets attached to the shell, as shown in Figures 3 to 8,
and are retained by clasps or keys so arranged as to admit of their easy removal
when necessary. These pipes may be so connected with the boxes c that the
cover x may be removed when renewing the tuyers without disturbing them by
making the pipe connecting the branch pipes a, b, with the chambers c in two parts,
and connecting them by screw collars above the level of the tuyer box.
The ends of the pipes Y, Z, connecting with the blast pipes are bent at right
angles to them, and are arranged to fit snugly but slide freely in the short pipes X, W,
which are firmly fixed to the end of the converter.
When the converter is large, there should be two tap holes C', similar to those of
a blast furnace, and stopped in a similar manner, but having a plate to cover over
them, wedged to the end of the converter, so that no accident may occur by the
forcing out of the stoppers during the operation; these tap holes being also provided
with spouts C2 for directing the molten iron or steel into the ladles.
The tuyers are arranged alternately, that is, a tuyer in one side is opposite the
space between two tuyers on the other side, and all are placed a few inches above
the bottom which slopes both ways from the centre down to the tap holes, as shown
in Figure 3, in order to facilitate the flow of the cinder or slag after the metal is
tapped off, and thereby prevent any of it remaining from one operation to another.
The gases escape from the converter through an opening g into the external air
or into a chamber in which the ore or blast can be heated. The converter is charged
through apertures g', which are closed with fire-brick stoppers et properly luted, and
fastened before the blast is let on. The stoppers are connected with a balance
weight and lever having a horizontal as well as a vertical motion, so that they may
be removed without difficulty and placed in a position where they will not interfere
with the charging operations.
When in place they are secured by a clamp bar and wedges similar to those used
is gas works to secure the covers of the retorts. A funnel 92 may be used in charging
to prevent such wear of the lining as might interfere with the proper fitting of the
stoppers.
In another modification, illustrated in Figures 9 and 10, the movable converter 02
is made with the tuyers in the sides, and like those above described (over which it
possesses some advantages), its shell is made of wrought-iron plates lined inside
with fire-bricks or other refractory material, ranimed in between interior ribs p of
I iron. This converter has two cast-iron rings 9 secured to the shell, and connected
to inner rings q² by radial arms q', and to which inner rings are secured cog
wheels, through which motion is given to the converter, the outer rings q resting
on antifriction rollers p' on standards secured to a suitable foundation.
The pipes Q, S, are fixed to the shell of the converter, as are also the pipes X, W,
into which the elbows of the movable pipes Y, Z, are arranged to slide. To the
ends of the pipes Q, S, (terminating in the centres of the rings q) are bolted short
and slightly conical pipes, into which the elbows of the pipes K, R, fit; these short
conical pipes must be very carefully centred, so that when the converter moves
around its axis of revolution the joints between them and the pipes K, R, will work
smoothly and remain gas-tight. All the other parts are similar to those herein-
before described, and will not require description, as the same letters are marked on
similar parts in this and the permanent converter.
The apparatus used in operating the valves in the pipes K, R, and regulating the
admission of the gas and air blasts to the tuyers is shown in Figure 11. One end
of an arm w² is secured to the spindle of the valve W' of the pipe K, and the other
end is connected by a rod e³ to the piston rod y' of a piston o³, adapted to a
cylinder, which communicates with another cylinder by pipes w³, w, in the 5
manner shown, and which pipes pass from the converter under the floor to the
operator's stand, and have their horizontal parts connected with the waste water

page_text: reservoir by pipes, in which are cocks c, c², for emptying them when necessary.
Immediately under the stand the pipes w³, w, are connected with a supply pipe w
by a horizontal pipe w7, having in it cocks c, c, the former for cutting off both
pipes from the supply pipe, and the latter for cutting off the connection between
the pipes themselves. The piston o* in the cylinder is connected with a piston o
in a third cylinder vi by the part y³ of the piston rod y², the upper end of which
carries an index arm arranged so as to show exactly the extent of the area of the
opening of the valve W', so that the flow of the gas may be regulated with certainty.
The cylinder 3 is connected with the supply pipe we through a cock c³ and
connecting pipes.
In the supply pipe w is a cock for purposes herein-after stated, and there is a
waste water pipe 20 leading to the waste water reservoir.
Apparatus similar in every respect to that described is used in connection with
the air valve pipe R, so as to regulate the flow of the atmospheric air to the tuyers.
The cylinder connected with the gas valve 20¹ and the similar cylinder con-
nected with the air valve w² are so placed that both can be worked at the same
time by a boy standing between them.
When commencing operations the gas valve W₁ is shut and clamped in that
position, the piston of being at the bottom of the cylinder 4, and consequently the
pistons o, o, at the tops of their respective cylinders. The cocks c, c, c7, being
closed, the cocks c', c", are opened, and the water from the supply pipe wallowed
to flow into and fill the cylinders v³, v, after which the valve W₁ is unclamped and
the cocks c¹, c, are closed and remain so during the subsequent operations.
In order to open the valve W¹ it is only necessary to gradually open the cock c³
and then turn the cock slowly so as to let the water flow above the piston in the
cylinder, and press it down, and therefore depress the piston in the cylinder v³,
connected with it by the common piston rod. By this means the water below the
piston in the cylinder 3 is forced through the pipe w³ into the cylinder, and the
piston in it pressed upward, thereby displacing the water above the piston and
forcing it to flow back through the pipe w, and fill the vacant space caused by the
descending piston in the cylinder v. A reverse motion of the valve cs will of
course close the valve W₁. When it is necessary that the valve shall only be
partially opened the index arm is brought to the desired position, and the cock c³
closed so as to remove the pressure from the piston in the cylinder 2, and thus
cause it to remain at rest.
The gas purifier I, Figure 12, has an external shell of wrought-iron, and an
internal lining of fire-brick for the purpose of preventing as far as possible the loss
of heat by radiation. The purifier is cylindrical and is divided into two parts by
an inverted conical bottom f, the lower part f being the cinder trap into which
pieces of the fuel too large to float in the gaseous atmosphere in the purifier
will fall.
Attached to the bottom f is a short pipe f³ having a cock or valve f¹, through
which communication is formed between the upper and lower divisions. The rod f*,
by which the cock is operated, passes through a stuffing box f³. J is a pipe which
leads from the cinder trap to the open air, and has a cock J₁; and h, h', are man-
holes, the former being for the purpose of repairs, and the latter for the removal of
the cinders from the cinder trap, both man-holes being furnished with suitable detach-
able covers.
The cock fis always closed before the cock J¹ is opened, and vice
versa. The pipe K communicates with the converter, and the pipe H with the
generator, which will now be described, reference being had to Figures 13 and
14, which are vertical sections, and Figure 15, a vertical section of the feeding
device; and to Figures 16, 17, and 18, which are detached views drawn to an
enlarged scale.
The generator A is a cylindrical vessel made of wrought-iron plates, and lined
with fire-brick, and has an ash-pit n². On the top of the vessel is a feeding device,
of which a piston o is adapted to a cylinder V, and operated either by steam or
water power.
The rod y of this piston is connected to a piston U in a second

page_text: cylinder T, in which the fuel is placed before it is fed into the generator A. The
fuel is charged into the cylinder T through an aperture e; G is a pipe, which
connects the interior of a gas-tight valve box E with the cylinder T, and has a
cock Gl Another pipe B connects a hollow truncated cone Z¹, forming the
bottom of the cylinder T, with the open air, and has a cock B³. A poker F passes
through a gas-tight stuffing box into the lower part of the hollow cone Z¹, for the
purpose of loosening the fuel, in case it should become jammed; and F¹ is a lever by
which the poker F is operated. The cylinders T, V, and their attachments are
supported by girders, as shown, which relieve the crown of the generator A from
pressure, and also support the floor on which the men stand when at work.
The valve box E contains a valve E', and has a double-top, bottom, and sides, so
as to form spaces through which water can circulate freely during the whole time
that the fuel in the generator A is ignited, whether work is going on or not, in
order to preserve the surfaces of the valve and seat.
Water may be supplied to the said spaces from an elevated reservoir, and
may be discharged from the spaces through suitable pipes, so that the valve
box shall always be in a comparatively cool condition.
The valve E is hollow, as is also the valve rod which passes through a stuffing
box, and is connected to any device for operating the valve by steam or water
pressure.
A cold water pipe a extends through the hollow valve rod as to within a few
inches of the end of the valve E', and an elastic tube d' connects with the pipe a®
through the side of the hollow valve rod a³, and conveys cold water to the valve E¹.
The water after cooling the valve E¹ passes out through a space a between the
external surface of the pipe a" and the internal surface of the hollow valve rod, and
thence through a second elastic tube, not shown on the Drawings, being similar to
the tube d', and on the opposite side of the hollow valve rod a³.
A circular pipe D¹ surrounds the upper part of the generator A, and is supported
on brackets rivetted to the wrought-iron shell; it is connected with the interior of
the generator by openings ¹, and also with the purifier I, Figure 12, by the pipe H,
which has a cock H, through which the gas generated is conveyed. Another
circular pipe D surrounds the lower part of the generator A, and communicates with
its interior through pipes or tuyers j, and through another pipe D³, with the main
blast pipe. D³ is a cock in the pipe D2 for the purpose of cutting off the blast from
the generator A. Another pipe k¹ connects the blast pipe D with the ash-pit
n2, and has a cock 2. Another pipe leads from the ash-pit to the open air, and
has a cock. A cast-iron ring 75, of the form shown in Figures 13 and 14, has
two cold water supply pipes h7, and two hot water discharge pipes h², in order that the
water may not become overheated. This ring is supported by girders i¹, which
rest on the brick lining of the ash-pit, and may be made hollow, and have a stream
of cold water passed through them. The grate bars g³ are also supported by these
girders, and are supplied with streams of cold water through pipes t². A valve V₁ is
fitted to the ring p, and, with the exception that it is slightly wedge-shaped, is
similar in every respect to the valve E¹, herein-before described, and has a cold
water tube 6 supplied through an elastic tube t, and a warm water space b
connected with an elastic discharge tube, not shown on the Drawing, being on the
opposite side to the supply pipe t7.
The hollow valve rod p' has a screw thread cut on its external surface, and
adapted to a screw on the internal surface of the nave of a wheel c2, which is tight
against a bracket plate m³, and is kept firmly in its place by a follower m² let into
the nave, as shown. It is evident therefore that by revolving the wheel c², the
valve rod p¹ will be moved horizontally in the required direction, and the valve V₁
shut or opened, as desired. The valve V' is always open except when it is found
necessary to clean out the ash-pit. As pieces of incombustible material may be too
large to fall through the grate bars, a poker p³ is employed to remove them. This
poker has a lateral but not a vertical motion, and passes through a hollow stopper ³,
which revolves around its vertical axis in a case rivetted to the wrought-iron

page_text: shell. The stopper r¹ is hollow, being cylindrical inside and slightly conical on its
outer surface, fitting exactly into its case 2. The central hollow of the stopper I
forms the stuffing box, which, like the other stuffing boxes and joints connected
with this apparatus subject to a high temperature, is packed with asbestos in the
form of paper or cloth, or other suitable form. A small quantity of graphite is
placed around and in contact with the movable member, which in this case is the
poker, to which the packing is pressed closely by screwing in. The incom-
bustible material which falls through the grate bars is removed from the ash-pit
at n³.
OPERATION.
After the lining in the generator has been dried, the cocks ², D³, are closed, but
the valves E', V₁, remain open, as well as the ash-pit door n. The piston U is
raised above the upper edge of the aperture e in the charging cylinder T,
Bee Figure 15. The lower part of the generator A is filled up to about the level of
the tuyers with small pieces of thoroughly dried wood through the aperture e;
coke or charcoal is then charged on to the wood through the same aperture until the
generator is filled, after which the fire is lighted at the grate bars g³, and fed by an air
draught through the ash-pit opening n³. As soon as the fuel has been properly ignited,
the grate bars and ash-pit are cleaned out, and the opening n³ closed. The valve
E' is now closed, as are also the cocks G', H¹, 5, so as to make the generator gas-
tight. The cock D³ is then partially opened, and a gentle air blast allowed to
enter the fire through the pipe D and the tuyers j, until the gases in the generator
have attained their maximum pressure, after which the cock D³ is fully opened.
When it is necessary to supply fuel to the fire, after the gases in the generator have
attained their maximum pressure, the piston U in the charging cylinder T is raised
above the charging aperture e, and the former filled to within a few inches of the
lower edge of the said aperture with fuel, which may be coke, coal, charcoal, or
thoroughly dried wood; the piston U is then lowered on the fuel, in which position
it cuts off all communication between the space occupied by the fuel and the open
air. The cock B5 is now closed, and the cock G¹ opened to allow the gases in the
generator A to flow into the cylinder T below the piston U, and establish an
equilibrium of pressure above and below the valve E', which is then drawn back,
and the fuel is allowed to drop into the generator A. The cock G¹ is now closed,
and the piston U lowered to the junction of the cylinder T with the hollow cone Z¹;
the valve El is then pushed forward, and the cock B opened to allow the gases in
the hollow cone Z₁ to pass into the open air. The equilibrium being thus
destroyed, the valve E¹ is forced against its seat on the under side of the cover of
the valve box E by the gases in the generator A. The piston U is again raised
above the aperture e, and the charging continued as before. If the fuel should
jam in the lower part of the cone Z₁ it can be loosened by the operating poker F
or other equivalent device.
When it is necessary to remove the ashes from the ash-pit n² the cock D³ is
closed, and the wedge-shaped slide valve V' pushed forward by turning the wheel c²
until it is tightly pressed against the ring p³ by being jammed between it and the
grate bars gs, which slope at the same angle as the lower side of the valve VI, and
thus cause its upper surface to remain horizontal. The cock ³ is now opened, and
the gases in the ash-pit allowed to flow into the open air until the pressure inside
and out are the same or nearly so; the cock k is then opened, and the remainder of
the gas removed by the atmospheric air flowing through the pipe k', and thence
through the pipe ³. Care must be taken to remove all the gases from the ash-pit
n² before opening the door n', so as to avoid the explosion that would take place if
any ignited matter chanced to be in the ash-pit with the gases at the time of
opening the door n*. As soon as all the gases are thus removed the cock k² is closed,
the door n opened, and the ash-pit cleaned out, after which the cock is closed, and
the door replaced as before. If the tuyers enter below instead of above the grate
bars g³ the pipes k¹ will be dispensed with, and the door n³ removed as soon as the

page_text: .
valve V' is closed, and the pressure lowered to that of the atmosphere by opening
the cock k³.
The purifier I, Figure 12, is prepared by luting and firmly fixing the covers of
the man-holes h, h, closing the cock J', and opening the cock f. When it is
necessary to remove the cinders from the trap f the cock f' is closed, and the
cock J opened, so as to allow the gases in the trap f to flow into the open air
until the pressure inside is equal to the pressure of the atmosphere; the man-hole h¹
is then opened, and the cinders removed, after which the cover is replaced as before,
and the cock J¹ closed, and the cock f' opened.
When coke or charcoal is used for fuel the gases which pass from the generator
into the purifier are nitrogen and carbonic oxide, but when coal is used there will
be an admixture of hydrocarbons, which are formed by distillation in the upper
part of the generator. The formation of the other gases may be described as
follows:-
Atmospheric air is composed of two gases, namely, nitrogen and oxygen, the latter
of which combines with carbon at a high temperature, setting the nitrogen free.
It forms two combinations with carbon, namely, one equivalent of carbon to one of
oxygen, forming carbonic oxide, and one equivalent of carbon to two of oxygen,
forming carbonic acid. These gases pass very readily from one to the other at a
high temperature, according to the excess of oxygen or carbon, hence it is evident
that at the front of the tuyers in the generator, where the oxygen of the blast is in
excess, carbonic acid must always be formed, and also that as this gas passes through
the incandescent fuel it will combine with an additional equivalent of carbon, and
become carbonic oxide, in which form it will pass mixed with nitrogen and also
with hydrocarbons when coal is the fuel employed into the purifier, and thence
through the pipes K, Q, Z, b, into the chamber c under the tuyers in the
converter.
The term carbonic oxide will be understood in this Specification to mean carbonic
oxide, with its associated gas or gases as they pass into the converter from the
generator.
When charging the converter the bottom is first covered with a thin layer of
ignited fuel, and on this is placed the ore to be converted. It must be washed and
broken to about the size of road metal, and spread as evenly as possible over the
ignited fuel.
A very gentle air blast is then put on through the blast pipe R, so as
to cause the fuel in the bottom of the converter to burn to flame. The cock or
valve W₁ is then gradually opened, permitting streams or jets of carbonic oxide gas
to flow through the pipes b, and meet similar streams of atmospheric air through the
pipes a in the chambers c, where they commingle and pass through the tuyers d in
this mixed condition. On coming in contact with the flame in the bottom of the
converter the carbonic oxide burns to carbonic acid, and generates an intense heat,
sufficient to melt even malleable iron, and by this heat the ore is fused. Instead of
placing fuel in the bottom of the converter the gases may be ignited at the mouth
of the same. After fusion is completed the atmospheric air is cut off by closing the
cock W, and the flow of carbonic oxide gas through the molten mass continued
until the ore is reduced, the gascs formed escaping through the throat. In order to
facilitate this part of the operation the cocks s, t, are opened to permit the powdered
carbon previously placed in the receiver M to pass out through its nozzle v, and
borne on by the current of the gases to pass up with it into the molten mass, and
combine with the oxygen in it, thereby materially assisting in the deoxidation of
This powdered carbon may be pulverized coke, charcoal, coal dust, or
any other suitable carbonaceous matter. The ore thus reduced may now be fluxed
by such agents in a powdered or gaseous state, as may be found most desirable.
The flux receiver S', similar and similarly situated to the carbon receiver M, but
on the opposite side of the converter, is used for the powdered or gaseous flux,
which is carried through the tuyers, and thence upward through the molten mass,
usually by the air blast. If however the ore contains a considerable per-centage of
silica or other foreign matter the carbonic oxide gas should be used as the vehicle
the ore.

page_text: or means by which the flux is carried through the molten mass, using the carbon
receiver on the same side for the powdered flux. If air be used when the quantity of
the impurities is large there will be an unnecessary waste of metal by the formation
of silicates; on the other hand, if the gases are made the vehicle when the quantity
of the impurities is small, there will be a waste of fuel in generating the gas for that
purpose. An analysis of the ore will determine which should be used.
From one cause or another the temperature of the bath may be somewhat reduced
below the intense heat required to keep the malleable iron in that state of fusion
necessary for the subsequent operations. In this case the air and gas must be used
at the same time in order to restore the lost heat, and the air blast employed to
carry the flux from the flux receiver proper to the tuyers, whence it will be carried
upward through the molten mass by the carbonic acid gas formed at their inner
ends. It will be observed that the mechanical arrangements are such as to meet all
these cases.
Under certain circumstances it will be found desirable to mix limestone broken
into small pieces with the ore when charging the converter. The ore baving been
thus reduced and fluxed the converter is turned sufficiently to allow the cinder or
slag to flow into the ladle or other vessel prepared for that purpose. After the slag
has been removed the converter is brought again into the vertical position (the full
pressure of the air or gas being put on just before it begins to move), and a stream
of atmospheric air or carbonic acid gas sent through the metal to remove any carbon
that may have been in excess of that required for reduction, so that the proper
quantity of carbonic oxide gas and powdered carbon required to cause the desired
degree of hardness may be accurately determined. When thus purified the metal
can be carburized to any degree of hardness by cutting off the atmospheric air, and
sending through the molten metal a determined weight of powdered carbon from
the refilled carbon receiver in streams or jets of carbonic oxide gas flowing for a
definite time. As soon as this last operation is completed the converter is turned,
the gas cut off, and the metal poured into ladles ready for casting into ingots or
moulds of any required shape.
When it is desired to change scrap iron or pig metal into steel it must be broken
or cut into small pieces, and spread as evenly as possible on a thin layer of ignited
fuel in the bottom of the converter. The atmospheric air and carbonic oxide gas
are then turned on, as herein-before described; but in this case the carbonic oxide
gas should be in excess in the fusing flame, a part only being burnt to carbonic
acid gas, so as to avoid the unnecessary waste that would otherwise be caused by
the oxidation of the metal. After fusion is completed the removal of the impurities
and the final carburization of the metal are accomplished in the same manner, and
by the same means employed in the case of metal made direct from the ore.
If the ore or metal contain phosphorous or sulphur, and it is considered desirable
to use the carbonic oxide gas, as the vehicle by which the regular flux is carried
through the molten mass, the agents, such as chlorine or chloride of sodium,
employed for their removal must be used after the fluxing of the other impurities
is completed, and should be carried through the molten metal by atmospheric air
or carbonic acid gas; but if the regular flux is carried into the metal by either
atmospheric air or carbonic acid gas the agents used for the removal of the
phosphorous or sulphur may be mixed with it, and all the impurities acted on at
the same time.
If gases are used as fluxes instead of powder for the removal of phosphorous or
sulphur, they are put into a gas receiver, similarly placed to the powder flux
receiver, and blown through the molten metal in a similar manner to that herein-
before described.
If steel is made by the ordinary process now employed, and it is only necessary
to remove the phosphorous or sulphur from the molten metal before carburization,
the generator and gas pipes can be dispensed with, the air pipes alone being
necessary.

page_text: The cocks W¹, W2, must be gradually opened and shut when the converter is in
a vertical position, so that the pressure at the point of the tuyers may be constant.
When the permanent converter is employed the slag or cinder cannot be removed
until the iron is tapped off, on account of its floating on the molten metal.
It must also be remarked, that the flow of carbonic oxide gas must be continued
during the time that the iron and slag are running from the converter, and at a
pressure sufficient to prevent them from filling the holes in the tuyers. The metal
is tapped off in exactly the same manner as the iron from the blast furnace, and
the tap hole stopped in the same manner, except that in this case there is the
additional security of the wedged cover over it.
With these exceptions the process is substantially the same as that herein-before
described, and as the same letters are employed in similar parts of the movable and
the permanent converter, the description given will answer for both.
The direct process may also be conducted as follows:-The ore can be melted in
a separate furnace, such as a reverberatory furnace or any other suitable furnace,
and poured into the converter in a liquid state, where it can be deoxidized, fluxed,
and carburized, as herein-before stated; or after deoxidation and fluxing are com-
pleted, and the cinder removed, the metal can be carburized in the manner now
practiced by pouring into it either spiegeleisen or some other highly carburized
iron previously melted in a separate furnace or cupola.
Having thus fully described the direct process, and the apparatus connected
therewith constituting the present Invention, I would remark in conclusion, that
the Inventor, the said Mark John Hamilton, desires it to be distinctly understood,
that he does not limit his Invention to the exact details of the process and
apparatus, as herein-before described, but to the general and distinctive character
of the Invention, both with regard to the process and the apparatus necessary to
put the same in operation, and I therefore claim as the Invention communicated to
me by the said Mark John Hamilton,―
First. As a means of operating the piston U in the charging cylinder T, the
piston o in the cylinder V, and connected with the piston U by the piston rod y.
Second. In combination with the generator A and the charging cylinder T,
through the hydraulic valve box E, the pipe G, for the purpose of equalizing the
pressure above and below the hollow hydraulic valve E¹.
Third. In combination with the charging cylinder T and the generator A, through
the bydraulic valve box E, the hollow hydraulic valve E'.
Fourth. In combination with the generator A and the charging cylinder T, the
reciprocating poker F in the hollow truncated cone Z'.
Fifth. The truncated wedge-shaped hydraulic valve V¹ in combination with the
generator A, the ring p5, and the grate bars g³.
Sixth. As a means of operating the truncated wedge-shaped hydraulic valve V¹,
the wheel c³, connected therewith by the hollow hydraulic valve rod pl.
Seventh. The stopper 1 in combination with the generator A, through the
stopper case ³, for the purpose herein-before described.
Eighth. The oblong permanent converter, substantially as described and shown
on the Drawings.
Ninth. The oblong movable converter having the tuyers in the sides, substantially
as described and shown on the Drawings.
Tenth. In combination with the converters, having the tuyers in the sides, the
tuyer box x¹ and the tuyer box cover x, having in it the chambers c.
Eleventh. As a means of operating the valve W¹, the piston 0%, in the cylinder v³,
connected therewith by the piston rod y, the connecting rod e³, and the valve
crank w².
Twelfth. In combination with the cylinder v* and the piston 0%, the water
pipes w³, w, connecting the cylinder with the cylinder v, for the purpose of
giving motion to the piston o³ in the cylinder v.
Thirteenth. In combination with the pipes w³, w, the cylinder
piston o'
and the

page_text: Fourteenth. As a means of operating the piston o' in the cylinder w, the piston o³
in the cylinder v³, connected therewith by the piston rod y³, the part y³ thereof
being connected with an index arm, as shown on the Drawings.
Fifteenth. The perforated nozzle N¹ in combination with the carbon receiver M
(the carbon receiver itself not being claimed), 'and through the pipe Qwith the
pipe Z, and similarly the perforated nozzle N' in combination with the flux
receiver S', and through the pipe S with the pipe Y.
Sixteenth. The pipe Z so arranged as to receive the carbonic oxide and powdered
carbon or flux from the pipe Q, and conduct the same to the tuyers d through the
pipes b and the chambers c.
Seventeenth. The pipe Y, so arranged as to receive atmospheric air and flux
through the pipe S, and conduct the same to the tuyers & through the pipes a and
the chambers c.
Eighteenth. The branch pipes a, b, in combination with the pipes Y, Z, and the
chambers c, for the purpose specified.
Nineteenth. In combination with the tuyers d the chambers c, so arranged as to
permit the commingling of the atmospheric air and carbonic oxide gas prior to
their passage through the tuyers, and thence upwards through the molten mass in
the converter.
Twentieth. The process of deoxidizing molten ore by blowing carbonic oxide gas,
with or without powdered carbon, through the tuyers in the converter, and thence
upwards through the inolten mass.
Twenty-first. The process of fluxing molten ore or metal by jets of powdered
fluxing agents, blown through the tuyers in the converter, and thence through the
molten mass therein.
Twenty-second. The process of fluxing molten ore or metal by jets of gaseous
fluxing material, blown through the tuyers in the converter, and thence through
the molten mass therein.
Twenty-third. The process of carburizing molten iron by carbonic oxide gas,
with or without powdered carbon, blown through the tuyers, and thence through
the molten metal.
And, Twenty-fourth. The herein described mode of supplying fuel to the generator
without changing the pressure of the gases therein; all substantially as described,
and as illustrated on the accompanying Sheets of Drawings.
In witness whereof, I, the said Bristow Hunt, have hereunto set my hand and
seal, this Fifth day of March, in the year of our Lord One thousand eight
hundred and seventy-eight.
BRISTOW HUNT. (LS)