IMPROVEMENTS IN SMELTING IRON AND STEEL, AND IN FURNACES AND APPARATUS EMPLOYED IN CONNECTION THEREWITH, PARTS OF WHICH IMPROVE- Maxim ADD ATRO ADDITOADER TO REARNED ATIVE GAO DODVICES GENERALLY " PROVISIONAL SPECIFICATION
Year: 1872

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 FURNACES AND
APPARATUS EMPLOYED IN CONNECTION THEREWITH, PARTS OF WHICH IMPROVE-
Maxim ADD ATRO ADDITOADER TO REARNED ATIVE GAO DODVICES GENERALLY
"
PROVISIONAL SPECIFICATION left by the said Charles William
Siemens at the Office of the Commissioners of Patents, with his
Petition, on the 3rd December 1872.
I, CHARLES WILLIAM SIEMENS, of No. 3, Great George Street, West-
minster, in the County of Middlesex, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN SMELTING IRON AND STEEL, AND IN
FURNACES AND APPARATUS EMPLOYED IN CONNECTION THEREWITH, PARTS OF WHICH
IMPROVEMENTS ARE ALSO APPLICABLE TO REGENERATIVE GAS FURNACES GENERALLY,'
to be as follows:-
-
"
In smelting iron ores, either in the blast furnace or in reverberatory

page_text: or fluid condition with reducing agents to deprive the ore of its oxygen,
and also to convert the solid substances contained in or mixed with the
ore, such as silica, alumina, and lime into a fluid slag, in order to
separate them from the solid or fluid metal produced.
For effecting the reduction of the ore I described in the Specification
to Letters Patent granted to me on the 10th June 1868, No. 1892, a
rotatory furnace, and in order to separate the spongy iron thus obtained
from its solid admixtures, I caused it to fall into a bath of fluid pig
metal under the influence of intense heat, where the spongy iron was
dissolved, and the solid admixtures or gangue was converted into fluid
slag. In carrying this process into effect it was found, however, that
the reduced or spongy metal in the rotating furnace or drum absorbed
sulphur very readily from the flame and the fuel used for effecting the
reduction, and moreover the spongy iron would float upon the metallic
bath of the steel melting furnace without being readily dissolved or
incorporated with the bath, and would be partially re-oxidized by the
action of the flame while thus floating. In order to remedy these
defects I adopted the plan of first melting the ore, and then subjecting
the fluid ore to the reducing action of solid carbon under the influence
of intense heat.
According to the Invention for which I obtained Letters Patent on
the 15th November 1871, No. 3077, I effected the fusion of the ore con-
tinuously in a stationary furnace provided with feeding hoppers, and the
reduction and consolidation of the metal was effected in a rotatory
furnace which was heated by means of gas and regenerators, and was so
constructed that the gases entered and left the rotatory furnace or
chamber at one and the same end or axial throat, while a working door
was provided at the other end or axial throat, through which access was
gained to the chamber during the working of the furnace.
The
According to my present Invention I effect the entire operation of
heating, reducing, and separating the metal from its scoria in a rotatory
furnace similar in construction to the one last above referred to.
ore to be treated is crushed and mixed with a suitable proportion of lime,
manganese, or other fluxing material, according to the relative amount
and nature of the gangue which the ore contains, in order to form a
fluid scoria; or, a mixture of ores may be employed which produce a
fusible slag without admixture of lime or other fluxing material. A

page_text: given quantity, say, one ton, of this mixture is introduced into the
heated furnace while this is made to revolve slowly. The charging door
is closed, and from 20 to 30 minutes are allowed for the mass to become
heated throughout to a point approaching the fusing point of the ore.
A given amount of reducing agent, such as pure coal, or anthracite, or
coke, previously crushed, but not ground fine, or charcoal, or wood
(which latter should be dried and cut up into pieces beforehand) is
thereupon introduced, which reducing agent, in falling to the bottom of
the slowly rotating furnace or chamber is at once covered up by and
mixed with the heated ore, and a rapid reducing action ensues. During
this period of the process carbonic oxide gas is generated from the mass
in such quantities that it nearly suffices to supply the fuel necessary to
maintain an intense heat within the rotating chamber, the supply of
producer gas to the furnace is therefore nearly stopped, and care is taken
to increase the supply of heated air from the regenerators. The reduc-
tion of the iron and the combination of the gangue contained in the ore
with the fluxing material into a fusible slag are thus effected simul-
taneously and with great rapidity, and inasmuch as the mass supplies its
own gaseous fuel, no sulphur is introduced, such as would occur by the
use of the generally impure producer gas.
In the course of about one hour the reaction should be completed;
when the liquid scoria may be tapped off to liberate the partially
agglomerated masses of metallic iron. The producer gas is now turned
on, and the speed of rotation considerably increased, when the metal
within the furnace will rapidly form into a ball or balls, which may be
taken out and put through squeezers, hammers, and rolling machinery,
for the production of metallic wrought iron; or the balls may be passed
through squeezers or a hammer, and thrown while still hot into a bath
of molten pig metal in an intensely heated furnace for the production
of cast steel; or, when comparatively pure ores are used the balls may
be transferred to the steel melting furnace without being subjected to
hammering or squeezing for the more thorough separation of the scoria,
but in the latter case the use of a separate steel melting furnace with its
bath of pig metal may be entirely dispensed with, and the ball or balls
of metal produced in the rotating chamber may be there converted into
cast steel, or into a pure cast metal holding a medium position between
cast steel and cast iron. For this purpose the fluid scoria is tapped
from the rotatory furnace after the ball or balls are formed, and some hard

page_text: carbonaceous substance, such as crushed anthracite or coke is thrown in.
The furnace is put into slow rotation, and the heat thereof is raised,
when the ball or balls will soon be seen to sink into a fluid mass ready
to be tapped and cast into forms or moulds, as the case may be; or
instead of introducing hard carbonaceous substances to effect the fusion
of the ball or balls, broken pig metal or spiegel eisen or ferro-manganese
may be introduced to effect the same purpose. Spiegel eisen or ferro-
manganese is especially desirable or necessary if malleable cast steel is to
be produced.
: The proportions of carbonaceous matter required for the conversion
of one ton of ore depends upon the richness of the ore and upon the
nature of the carbonacous matter employed, as also upon the nature of
the iron or steel to be produced, and had best be determined in each
case by experience; but half a ton of solid carbonaceous matter to the
ton of iron or steel produced will be found sufficient under ordinary
circumstances. If anthracite or hard coke is the reducing agent
employed it may be crushed moderately fine and charged into the
rotatory furnace with the ore to be heated simultaneously with the
same.
I prefer to construct the rotatory furnace of a cylindrical form with
conical truncated ends, one of which leads to the orifices for the ingress
of the gases for supporting combustion, and for the egress of the gaseous
products of combustion, while at the other end is provided the working
door, and if balls of iron are to be produced I increase the thickness
of the refractory lining of the furnace in places so as to form projecting
circular belts internally, which have the effect of dividing the contents
of the furnace into several balls, to facilitate the labor of removing and
consolidating the iron produced.
The lining may be formed of any known refractory material but I
prefer to use bricks or lumps formed of a mixture of argillaceous clay
with bauxite (or alumina containing some peroxide of iron) and about
ten per cent. of plumbago, which materials are mixed intimately, formed
into bricks or lumps of suitable form, and burnt in kilns in the usual
way. In burning such bricks the oxide of iron contained in the bauxite
is converted by the plumbago into metallic iron, and a very refractory
material is produced, capable of resisting the action of scoria for a
length of time. These bricks are built loosely into the rotatory furnace,
which, after being heated internally to a white heat is charged with

page_text: pure ore or hammer slag while rotating slowly. This ore on melting soaks
in between the bricks constituting the lining, and cements them firmly
together. The excess of fused ore is then tapped off, and the furnace is
ready for work.
It is important that the regenerative gas furnace employed to heat the
rotatory chamber should be very powerful, and that consequently leakages
or stoppages in the reversing valves should be carefully avoided. For.
this purpose I employ, instead of the usual two reversing valves for air
and gas, one "turnstile" valve having a central orifice leading towards
the chimney surrounded by six orifices, two opposite ones of which lead
respectively to the gas and air supply channels, while the other four lead
to the four regenerators of the furnace. These orifices are all formed in
one cast-iron face, which is turned perfectly true and smooth, and upon
this face rests a dome-shaped moveable cap divided into three compart-
ments by radial partitions, one of which compartments communicates'
with a central space in the cap situated over and communicating with
the before-mentioned central orifice leading to the chimney. This central
space is closed at the top by a light wrought-iron cover suitably guided
to allow of vertical motion, which cover acts as a safety valve in case of
an explosion occurring by an admixture of air and gas in the chimney
flue at the time of reversing.
In reversing the position of the cover the compartment communi-
cating with the central passage is brought over two of the before-
mentioned orifices leading to one pair of the regenerators, while the other
two compartments are brought over the other orifices in such manner
that the gas orifice is thereby made to communicate with one of the
orifices leading to the second pair of regenerators, and the air orifice is
made to communicate with the other orifice leading to the second pair of
regenerators.
The influx of air into the rotatory furnace is accelerated by means of
a jet of compressed air directed through the axis of the air channel, the
force of which jet can be regulated by means of a valve to be worked by
the operator in front of the furnace.
The two last-described improvements are also applicable to regenera-
"

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles William Siemens in the Great Seal
Patent Office on the 2nd June 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
WILLIAM SIEMENS, of No. 3, Great George Street, Westminster, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Third day of December, in the
year of our Lord One thousand eight hundred and seventy-two, in the
thirty-sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Charles William Siemens, Her
special license that I, the said Charles William Siemens, my execu-
tors, administrators, and assigns, or such others as I, the said Charles
William Siemens, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN SMELTING IRON AND STEEL, AND IN FURNACES
AND APPARATUS EMPLOYED IN CONNECTION THEREWITH, PARTS OF WHICH IMPROVEMENTS
ARE ALSO APPLICABLE TO REGENERATIVE GAS FURNACES GENERALLY,”
upon the
condition (amongst others) that I, the said Charles William Siemens,
my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
७
NOW KNOW YE, that I, the said Charles William Siemens, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement thereof, reference being had
to the accompanying Sheets of Drawings, and to the figures and letters
marked thereon, that is to say :-
In smelting iron ores either in the blast furnace or in reverberatory
furnaces it is necessary to react upon the heated ore either in its solid or

page_text: fluid condition with reducing agents to deprive the ore of its oxygen,
and also to convert the solid substances contained in or mixed with the
ore, such as silica, alumina, and lime into a fluid slag in order to
separate them from the solid or fluid metal produced.
For effecting the reduction of the ore I described in the Specification
to Letters Patent granted to me on the 10th June, 1868, No. 1892, à
rotatory furnace, and in order to separate the spongy iron thus obtained
from its solid admixtures I caused it to fall into a bath of fluid pig metal
under the influence of intense heat, where the spongy iron was dissolved
and the solid admixture or gangue was converted into fluid slag. In
carrying this process into effect, it was found, however, that the reduced
or spongy metal in the rotating furnace or drum absorbed sulphur very
readily from the flame and the fuel used for effecting the reduction, and
moreover the spongy iron would float upon the metallic bath of the
steel melting furnace without being readily dissolved or incorporated
with the bath, and would be partially re-oxidized by the action of the
flame while thus floating. In order to remedy these defects, I adopted
the plan of first melting the ore and then subjecting the fluid ore to the
reducing action of solid carbon under the influence of intense heat.
According to the Invention for which I obtained Letters Patent on
the 15th November, 1871, No. 3077, I effected the fusion of the ore con-
tinuously in a stationary furnace provided with feeding hoppers, and the..
reduction and consolidation of the metal was effected in a rotatory
furnace, which was heated by means of gas and regenerators, and was so
constructed that the gases entered and left the rotatory furnace or:
chamber at one and the same end or axial throat, while a working door
was provided at the other end or axial throat through which access was
gained to the chamber during the working of the furnace.
According to my present Invention I effect the entire operation of '
heating, reducing, and separating the metal from its scoria in a rotatory
furnace, similar in construction to the one last above-referred to. The
ore to be heated is crushed and mixed with a suitable proportion of lime,
manganese, or other fluxing material, according to the relative amount
and nature of the gangue which the ore contains, in order to form a'
fluid scoria. Or a mixture of ores may be employed which produce a
fusible slag without admixture of lime or other fluxing material. A
given quantity, say one ton, of this mixture is introduced into the

page_text: heating furnace, while this is made to revolve slowly the charging door
is closed and from 20 to 30 minutes are allowed for the mass to become
heated throughout to a point approaching the fusing point of the ore.
A given amount of reducing agents, such as pure coal, or anthracite,
or coke, previously crushed but not ground fine, or charcoal, or wood,
(which latter should be dried and cut up into pieces beforehand) is
thereupon introduced, which reducing agent, in falling to the bottom of
the slowly rotating furnace or chamber, is at once covered up by and
mixed with the heated ore, and a rapid reducing action ensues. The
mixing of the reducing agent with the ore may then be accelerated by a
quicker rotation of the chamber. During this period of the process,
carbonic oxide gas is generated from the mass in such quantities that it
nearly suffices to supply the fuel necessary to maintain an intense heat
within the rotating chamber; the supply of producer gas to the furnace
is thereupon nearly stopped, and care is taken to increase the supply of
heated air from the regenerators. The reduction of the iron and the
combination of the gangue contained in the ore with the fluxing
material into a fusible slag are thus effected simultaneously and with
great rapidity, and, inasmuch as the mass supplies the greater part of
its own gaseous fuel, little or no sulphur is introduced, such as would
occur by the use of the generally impure producer gas.
In the course of about one hour the reaction should be completed,
when the liquid scoria may be tapped off to liberate the partially
agglomerated masses of metallic iron. The producer gas is now turned
on and the speed of rotation considerably increased, when the metal
within the furnace will rapidly form into a ball or balls, which may be
taken out and put through squeezers, hammers, and rolling machinery
for the production of metallic wrought iron. Or the balls may be passed
through squeezers or a hammer, and thrown while still hot into a bath
of molten pig metal in an intensely heated furnace for the production of
cast steel. Or, when comparatively pure ores are used the balls may be
transferred to the steel melting furnace without being subjected to
hammering or squeezing for the more thorough separation of the scoria.
But in the latter case the use of a separate steel melting furnace with
its bath of pig metal may be entirely dispensed with, and the ball or
balls of metal produced in the rotating chamber may be there converted
into cast steel or into a pure cast metal, holding a medium position
between cast steel and cast iron. For this purpose the fluid scoria is

page_text: tapped from the rotatory furnace after the ball or balls are formed, and
some hard carbonaceous substance, such as crushed anthracite or coke, is
thrown in. The furnace is put into slow rotation and the heat thereof is
raised, when the ball or balls will soon be seen to sink into a fluid mass
ready to be tapped and cast into forms or moulds, as the case may be.
Or, instead of introducing hard carbonaceous substances to effect the
fusion of the ball or balls, broken or fused pig metal, or spiegel eisen, or
ferro-manganese may
be introduced to effect the same purpose.
Spiegel eisen or ferro-manganese is especially desirable or necessary if
malleable cast steel is to be produced.
The proportions of carbonaceous matter required for the conversion of
one ton of ore depends upon the richness of the ore and upon the nature
of the carbonaceous matter employed, as also upon the nature of the iron
or steel to be produced, and had best be determined in each case by
experience; but half a ton of solid carbonaceous matter to the ton of
iron or steel produced will be found sufficient under ordinary circum-
stances. If anthracite or hard coke is the reducing agent employed, it
may be crushed moderately fine, and charged into the rotatory furnace
with the ore, to be heated simultaneously with the same; and in the
same manner coal or wood may be introduced along with the ore, these
becoming converted respectively into coke or charcoal by the heat.
I prefer to construct and arrange the rotatory furnace as shown in the
two Sheets of accompanying Drawings.
Fig. 1, Sheet J., represents a longitudinal section taken on the line
marked A, A, in Fig. 2, which Figure represents in its lower part a
partial sectional plan on the line B, B, in Fig. 1, and in its upper part a
partial sectional plan on the line C, C, in Fig. 1. Fig. 3, Sheet II.,
represents on its left hand side a half transverse section on the line D, D,
in Fig. 1, and on its right hand side a half transverse section on the
line E, E, in Fig. 1. Fig. 4, Sheet II., represents a transverse section of
the rotating chamber taken on the line F, F, in Fig. 1. Fig. 5, Sheet II.,
represents a front elevation of the furnace, and Figs. 6 and 7, Sheet II.,
represent respectively a sectional plan and a vertical section of the
arrangement of the reversing valves for the flues, which will hereafter be
described.
The rotating chamber a is of cylindrical form, with truncated conical

page_text: ribs b, b, which rest on two pairs of rollers c, c. It has also a toothed
rib ¹, gearing with a pinion fixed on a shaft d, which is extended to the
working gear situated at any convenient distance from the front of the
furnace. This working gear is arranged as follows:-e is a shaft driven
by any convenient prime mover, having loosely mounted on it a large
and a small wheel e¹ and e², with a sliding clutch between them,
working on a feather on the shaft e, so that it can be moved to either
hand by a hand lever e*. The wheels e¹ and e² gear respectively with a
small and a large wheel d² and d², fixed on the shaft d. When the clutch e³
is in the middle position, as shewn in Figs. 1 and 2, no motion is
imparted by the revolving shaft e to the shaft d, and the rotatory
chamber a remains at rest. But when the clutch e³ is moved to the one
side or the other, so as to engage either of the wheels e¹ or e³, the shaft d
is caused to revolve, in the one case rapidly, and in the other case slowly,
and the rotatory chamber a can thus be made to rotate quickly or slowly
so as to suit the different stages of the process described above. The
front of the rotatory chamber a is fitted with a door a¹, mounted so as to
slide vertically between guides a², a², and counterbalanced by a weight
on a lever a³. In the front of the chamber a is a tap hole a', which, the
chamber a being turned round to the position shewn in Fig. 1, can be
tapped so as to discharge the contents of the chamber on to a slanting
shoot a*, whence they can be delivered into a truck a*, running on rails
below the furnace.
g,
The back of the chamber a is formed with a circular throat facing two
flues g', each of which is divided into two flues marked respectively g³,
g', 9', g. These last-mentioned flues communicate respectively with
four regenerative chambers h³, ha, ha, h, that is to say, the upper flues on
either side communicate with the larger chambers h¹ and h³, and the
lower flues with the smaller chambers * and h*. The four regenerative
chambers communicate respectively with four of the six divisions of the
reversing valve box k, the other two divisions of which communicate
respectively with k', the pipe for supplying combustible gas, and k³ the
pipe for supplying air. The central part of the valve box k (which is
shewn in Fig. 2 with its cap removed) communicates with a flue
leading to the chimney. The valve box k is surmounted by a cap 1 (of
which Fig. 6, Sheet II., shews a sectional plan on the line G, G, of
Fig. 7) having three divisions round a central part corresponding to the
central part of the valve box k, one of which divisions opens to this

page_text: central part. The cap 1 is truly faced on its under surface, so as to rest
on the truly faced upper surface of the valve box k, and it is mounted on
a vertical spindle so that it can turn in the manner of a rotating slide.
It will be readily seen that when this cap is turned into one position gas
from the pipe k¹ and air from the pipe k² can pass into two of the
regenerative chambers ¹, h³, on the one side, and thence by two of the
flues g² and g³ to the flue g, where, having been highly heated by their
passage through the regenerative chambers, they mingle and produce
intense flame. This flame enters the rotatory chamber a, and playing
round therein issues from it by the other flue g¹, and the products of
combustion thence pass by the flues 9* and g³ through the other pair of
regenerative chambers ³ and * (which they heat in passing), and up
through divisions of the valve box k, and down the central part thereof
to the chimney flue k³. The directions of the currents in one position of
the
cap Zare indicated by arrows.
When the one pair of regenerative chambers have become sufficiently
cooled by the passage of the air and gas through them, and the other
pair have become sufficiently heated by the passage through them of the
products of combustion from the rotatory chamber a, the cap of the
valve box kis turned round so as to alter the direction of the ingoing
currents of gas and air, sending them through the second pair of
regenerative chambers, and the direction of the products of combustion,
passing them through the former pair of chambers according to the
usual method of working regenerative gas furnaces. The cap of the
rotating valve is preferably made open at top and fitted with a light
cover which closes the orifice of the cap, but is capable of lifting so as
to act as a safefy valve, permitting the issue of gaseous matter in case
of explosion in the flues by admixture of air with gas at the time of
altering the valve.
The pipe for supplying combustible gas is provided with a stop
valve connected by levers and rods to a screw and hand wheel k³ at
the front of the furnace whereby the supply of gas can be regulated or
entirely cut off as may be desired. The pipe for supplying air is pro-
vided with a throttle valve also connected by levers and rods or chains
to a rod at the front of the furnace by drawing out or pushing in
which the supply of air can be regulated. The quantity of air supplied
by the pipe k can be increased beyond that due to the natural draught
by a jet of air from a blast pipe ³.

page_text: As the producer gas is generally supplied at a pressure somewhat
above that of the atmosphere, and as the acceleration of the air supply
cffected by the blast above described causes an increase of pressure in
the air, the furnace is thus worked under a plenum, so that any leakage
is outwards instead of inwards. It is obvious that this method of
working, and the rotary slide valve above described, are applicable to
regenerative gas furnaces generally.
The flue is provided with a damper kº connected by a chain to a
counterweight at the front of the furnace. Thus the relative supplies
of gas and air, and the general draught of the furnace can be readily
controlled by the attendant at the front of the furnace.
The rotatory chamber a may have lining of any known refractory
material that is not readily affected by scoria. I prefer however to use
for it a lining formed in the following manner:-I take the mineral
known as bauxite, consisting chiefly of alumina with a proportion of
peroxide of iron. I calcine it and reduce it to powder and mix with it
from ten to fifteen per cent. of powdered plumbago, graphite, or other
carbonaceous matter in a dense form, and such a quantity of argillaceous
clay or other binding material, such as lime, cement, or alkaline silicate
as is necessary to give cohesion. I form this mixture into bricks or
blocks of suitable form, and burn them in a kiln under the influence of
a reducing atmosphere. In burning these bricks the oxide of iron
contained in the bauxite is converted by the carbonaceous matter into
metallic iron, and a very refractory matter is thus produced capable of
resisting the action of scoria for a considerable time. If the iron oxide
be not in such large proportion in the bauxite as to render the mass
easily fusible, the admixture of carbonaceous matter may be dispensed
with. These bricks may be built inside the rotatory chamber with cement
made from the mixture above described used in an unburnt condition.
But I prefer to build them in loosely, and after heating the furnace to a
white heat to charge it with pure ore or hammer scale while rotating
slowly. The ore or scale is melted and sinks into the crevices between
the bricks, serving as a cement which binds them firmly together, and
also as a glaze which prevents access of air to the interior of the bricks.
When the bricks are so cemented and glazed the excess of fused ore or
scale is tapped off and the furnace is ready for work.
Instead of forming the compound above described into separate
bricks or blocks to be built into the furnace, it may be laid or rammed

page_text: in moist, and dried and baked in its place, after which the ore or hammer
scale is fused in the chamber, which has the effect of cementing cracks
in the lining and glazing its surface.
When the furnace is employed, as has already been described, for
puddling or forming balls, it is convenient that several balls of moderate
size should be produced instead of one large ball, which is difficult to
handle. In order to divide the contents of the furnace into several
such balls, I form on the lining internally projecting circular ribs m,
which have the effect of separating the semi-fluid mass into portions
during rotation, each such portion forming a ball. As these ribs, if
carried entirely round the interior of the chamber, would act as stops to
prevent the flow of a portion of the fluid contents towards the tap hole
at, I provide gaps m¹ in the ribs in the line of the tap hole, so that when
the rotatory chamber is turned with the tap hole downwards there shall
be a clear course for fluid along the bottom of the chamber.
Several gaps may be made in the periphery of these ribs, which serve
to prevent the sliding of the semi-fluid masses and give them a tendency
to roll, and this effect may be also attained by providing other pro-
jections on the inner surface of the lining, or giving the lining inwardly
a polygonal form.
Having thus described the nature of the said Invention, and in what
manner the same is to be performed, I claim, —
-
First. The process of effecting the separation of metallic iron from
heated or mingled with fluxing materials and carbonaceous matter, the
reaction being promoted by slow rotation of a rotative furnace, and
forming the separated metal by means of a quicker rotation into balls
for the production of wrought iron or puddled steel, or for the production
of cast steel in a separate furnace, substantially as herein described.
Second. The process of separating metallic iron from ore in the
manner and by the means above referred to, and converting the
separated metal into cast iron or cast steel in one and the same rotative
furnace by the farther addition of solid carbonaceous matter, cast iron,
spiegel eisen or ferro-manganese, substantially as herein described.
Third. The use for effecting the process above referred to of a
regenerative gas furnace, so that highly heated air is supplied for the.
combustion of the carbonic oxide produced by the reaction of the car-
bonaceous matter in the ore, substantially as herein described.

page_text: Fourth. The use for lining rotative furnaces employed in metallurgical
operations of a compound consisting chiefly of bauxite, substantially as
herein described.
Fifth. The method substantially as herein described of cementing
and glazing the bauxite lining of rotative furnaces by fused ore or
hammer scale.
Sixth. Forming the lining of rotative furnaces employed for the
production of iron with internally projecting circular ribs for dividing
the contents of such furnaces into several balls, substantially as herein
described.
Seventh. The use for regenerative gas furnaces, whether rotative or
not, of a single rotary slide valve for altering the inflow of air and gas
and the outflow of products of combustion, such valve being arranged
to act as a safety valve in case of explosion, substantially as herein
described.
Eighth. The method of increasing the inflow of air to regenerative
gas furnaces by means of a jet of air from a blast pipe, substantially as
herein described.
In witness whereof, I, the said Charles William Siemens have
hereunto set my hand and seal, this Thirty-first day of May,
in the year of our Lord One thousand eight hundred and seventy-
thro
described.
Eighth. The method of increasing the inflow of air to regenerative
gas furnaces by means of a jet of air from a blast pipe, substantially as
herein described.
In witness whereof, I, the said Charles William Siemens have
hereunto set my hand and seal, this Thirty-first day of May,
in the year of our Lord One thousand eight hundred and seventy-
tha
Witness,
JNO. A. HEAD,
3, Gt George St.,
London, S.W.
C. WILLIAM SIEMENS. (L.S.)