IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL AND HOMOGENEOUS MALLEABLE IRON, AND IN THE FUSION OR MELTING OF DIFFERENT KINDS OR QUALITIES OF IRON AND STEEL AND THEIR ALLOYS, AND ALSO IN THE CONSTRUCTION AND MODE OF WARKING SHE ANDRIAGE AND APPARATIS EMPLOYED FOR SUCH PURPOSES" PRO SP
Year: 1868

page_text: LETTERS PATENT to Henry Bessemer, of Queen Street Place, Cannon
Street, in the City of London, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF CAST STEEL AND HOMOGENEOUS MALLEABLE IRON,
AND IN THE FUSION OR MELTING OF DIFFERENT KINDS OR QUALITIES OF IRON
AND STEEL AND THEIR ALLOYS, AND ALSO IN THE CONSTRUCTION AND MODE OF
WARKING SHE ANDRIAGE AND APPARATIS EMPLOYED FOR SUCH PURPOSES"
PROVISIONAL SPECIFICATION left by the said Henry Bessemer at the
Office of the Commissioners of Patents, with his Petition, on the
10th November 1868.
I, HENRY BESSEMER, of Queen Street Place, Cannon Street, in the
City of London, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL, AND HOMOGENEOUS
MALLEABLE IRON, AND IN THE FUSION OR MELTING OF DIFFERENT KINDS OR
QUALITIES OF IRON AND STEEL AND THEIR ALLOYS, AND ALSO IN THE CONSTRUCTION
[Price 8d.]

page_text: AND MODE OF WORKING THE FURNACES AND APPARATUS EMPLOYED FOR SUCH
PURPOSES," to be as follows:-
When cast steel and homogeneous iron are made by the fusion in
crucibles of blistered steel or bar iron, or when they are made from
other qualities or kinds of iron or steel free or nearly free from carbon,
an extremely high temperature is required for their fusion, and in the
ordinary air furnaces employed for this purpose a very large quantity of
expensive fuel is consumed in this melting process. Now therefore one
of the chief objects sought to be obtained by means of my present
Invention is a more rapid and less expensive mode of fusing malleable
iron and steel of different kinds, and obtaining cast steel and homo-
geneous malleable iron therefrom. It will be understood that in fusing
substances requiring so extremely high a temperature as is necessary
to fuse malleable iron, that intensity of heat rather than quantity is the
condition essential to the successful working of furnaces employed for
that purpose, for a substance which requires 3000 degrees of temperature
to produce fusion may be kept at a temperature of 2900 degrees for
whole days in succession without becoming melted, when the mere
addition of only 100 or 200 degrees of heat would in that particular
case have produced a complete fusion of the substance in a very short
period of time. This well known law of matter operates most dis-
advantageously in those cases where the fusing point of the substance to
be operated upon closely approaches the limit of heat attainable by the
combustion of fuel by a draught or blast of air in ordinary furnaces.
It is well known that atmospheric air and other gaseous fluids in a
heated state require a still higher degree of temperature by their
compression or condensation into a smaller space than they had
previously occupied, such increase of temperature being in proportion
to their reduced bulk or to the number of atmospheres forced into the
space usually occupied by one. Now I avail myself of this last-named
property of
gaseous fluids, and I construct furnaces of sufficient strength
to withstand an internal pressure equal to two or more atmospheres,
and I retain in such furnaces the products of combustion under such
an excess of pressure over that of the external air as will produce
the high temperature necessary for rapidly fusing malleable iron and
steel of any kind or quality. I however desire it to be understood that
I do not propose by this means to generate a greater quantity of heat
by the combustion or union of a given quantity of carbon and oxygen

page_text: than is obtained by such means in well constructed furnaces, but by
retaining the heated products of combustion in a highly condensed or
compressed state in a close chamber or furnace I am enabled to retain a
much higher degree of temperature within the furnace than would result
from the same expenditure of fuel if the said gaseous matters were
allowed freely to expand into the larger space they would occupy under
ordinary atmospheric pressure.
In carrying my said Invention into practical operation I employ
several modified forms of furnace, depending partly on the kind or
quality of metal to be fused in them, and partly on the kind or quality
of the intended product when fused; but however much the form and
details of the furnace are varied, I in all cases prefer to construct the
shell or outer case of the furnace of rivetted plate iron or steel after the
manner of constructing steam boilers, and having all the joints well
caulked and rendered air-tight, and of sufficient strength to resist safely
the number of atmospheres or pounds pressure per square inch up to
which it is proposed to compress the products of combustion within
the furnace, allowance being also made for the additional pressure
caused by the expansion of the lining of the furnace. In some cases,
however, cast iron may be employed for the outer shell of the furnace,
the several parts being securely bolted together and caulked at the
joints; so in like manner those furnaces the shells of which are con-
structed of plate iron or steel may have their fittings made of cast iron
where the shape of the parts renders it desirable. The shell of the
furnace may be lined with good Stourbridge fire-bricks," "Dinas
bricks," or with plumbago or other refractory material, or it may he
lined with ground ganister, as practised in lining the Bessemer con-
verting vessels now used for making steel.
When the cheapness of the iron or steel produced is of more im-
portance than the extreme purity or high quality of the metal I prefer
to use the cupola form of furnace, consisting of an upright fixed
cylindrical or slightly conical vessel, with or without boshes, and having
a dome or covered top, through which the metal to be melted and the
fuel used for that purpose are admitted by an iron door faced with fire-
brick, but having externally a close metal fitting to prevent the escape
of flame and heated gases. The door may be circular in form, and be
supported on a strong moveable iron arm arranged with a lever and
cam or with a worm wheel and screw, for the purpose of securing the

page_text: door firmly in place. The iron arm also carries an upright cylinder of
plate iron having a moveable bottom or grid. Into this cylinder the
charge of fuel and metal is put, so that on the removal of the door the
cylinder is brought over the opening into the furnace; the bottom or
grid is then withdrawn, and the fuel and metal allowed to fall into the
furnace; after which the door is again moved over the opening and
secured firmly in place by means of the lever or screw; the blast should
be shut off, or nearly so, during the charging of the furnace, after which
it may be again turned on, and the operation of the furnace continued as
before.
There is also provided an escape opening (or openings) for the products
of combustion, the area of which is capable of alteration and adjustment
by means of small cylinders of fire-clay or other pieces of that material
inserted in the opening for the purpose of reducing its area. I prefer to
use several tuyeres for conveying the blast among the fuel, and to make
them of fire-clay or plumbago, although "water tuyeres" may be
employed in lieu thereof. The blast may be heated or cold, but I prefer
to heat it to a high temperature, and the pressure of the blast may range
from two to six pounds per square inch (more or less) over the pressure
of the confined gaseous products within the furnace; the pressure of the
latter will depend somewhat on the nature of the fuel employed, and
the more or less refractory character of the metal to be fused, and for
these and other reasons it may range from a few pounds per square inch
to several atmospheres. Some of the tuyeres employed direct the blast
horizontally or upwards, while others direct it downwards at about an
angle of 30 to 45 degrees, so as to heat as much as possible the lower
part of the furnace, and the molten metal collected there. The tuyeres
may also serve when required to convey any solid fluid or gaseous
matters into the furnace that may be found desirable to act on the fuel,
or as fuel, or on metal, or upon the impurities contained therein, as
already known or practiced with other furnaces. A tapping hole
is also provided as usual in cupola furnaces, and a door for cleaning
out the slags and for repairing the furnace when necessary; the tapping
hole I prefer to form by ramming loam around a small truncated cone
of well-burnt fire-clay, which may be easily driven into the furnace
by a blow of the tapping rod, and thus open the tap hole rapidly,
and of a size dependant on the diameter of the small end of the
conical piece of fire-clay. The metal when melted is thus drawn off

page_text: into a ladle, in order to be transferred to moulds, as practised in the
casting of ingots or other masses of Bessemer steel.
Although I have described a fixed or stationary cupola furnace, I
nevertheless prefer in most cases to employ another modification of the
apparatus, in which the cupola is suspended on trunnion's, and is capable
of being tipped or moved thereon in a manner similar to the motion of
the ordinary Bessemer converting vessel, and whereby the metal may
be poured out of the furnace from an opening situated above the level
of the metal, and thus much of the trouble and inconvenience of tapping
the metal from the lowest part of the furnace is avoided, while it also
affords a convenient means of pouring out a sample of the metal from
time to time and of running out any accumulated slags. When the
moveable form of cupola is employed the blast may be carried through
the hollow axis or trunnions, or it may be conveyed through an arrange-
ment of jointed pipes, so in like manner steam or water used for cooling
any part of the furnace may be conveyed to it. In order to prevent an
undue leakage of flame and heated gases from between the feeding door
and the adjacent parts, and their consequent rapid destruction by the
intense heat of the flame, I make a hollow channel around the door or
frame, into which I convey steam or a blast of air, the pressure of which
exceeds the pressure within the furnace, so that whatever leakage
unavoidably occurs, it is simply a leakage of steam or cold air inwards
instead of a leakage of flame outwards from the furnace. I also cool
the parts adjacent, and all openings where necessary, by the circulation
of water through suitable channels formed in those parts; and in furnaces
requiring a very large feeding door, in liew of using the lever or screw
arrangement I secure the door in place by means of air, steam, or water
pressure acting on the door by means of a piston with a greater force
than is exerted on the door in an opposite direction by the pressure of
the gases within the furnace, and thus secure the door firmly on its seat;
the removal of the pressure thus applied by opening or reversing a valve
allows the door to be removed readily. I would further remark that
the amount of pressure up to which the gaseous products are kept within
the furnace will depend chiefly on the regulation of the pressure of the
blast, the escape aperture being also regulated so as to prevent the
pressure going below or getting above the point desired. In some cases
the escape of the flame and heated matters may be regulated by a loaded
valve, the face of which is formed of well-burned fire-clay, in which
case a stop may be provided, so as to prevent the valve from entirely

page_text: closing; but I prefer that the escape should take place through one
or more plain apertures, as it may be thus more easily directed in a
manner so as effectually to utilize the heat of the escaping flame, which
may be directed on to or into a bath containing the spiegeleisen to be
used at the end of the process, or the heat may be employed to bring
up the temperature of the metal and fuel previous to its being intro-
duced into the furnace; it may also be used for heating the blast or to
generáte the steam required to work the blast engine by causing the
heated products to pass under or through the tubes of an ordinary steam
boiler. The fuel I prefer to use is a good härd coke or anthracite coal
as pure and free from sulphur as can be readily obtained; charcoal öt
other fuel may, however, be employed, and also lime or other fluxes
hitherto known or employed for keeping the slags or cinder in ä fluid
state, and although I prefer to employ solid fuel, it will nevertheless be
obvious that in cases where combustable gases and air are employed, as
in the furnaces known as "Siemens'," regenerative gas furnace or other
gas furnaces, or where liquid hydrocarbons are employed in the fusion
of malleable iron or steel or melting of iron of any kind, this same
system of increasing the temperature by confining the flame and heated
products of combustion under pressure within the furnace may be
employed, the gaseous and liquid fuels and air being forced by suitable
force pumps into the chamber or furnace, where combustion takes place,
and where they are retained under the desired pressure by means similar
to those herein-before described. In order to protect the metal from
an undue amount of oxidation or carburation during its passage down-
ward among the fuel and blast, I prefer to coat the metal with a
substance or compound capable of fusing at a moderate heat, and of
forming a vitreous or glassy covering to the metal; for this purpose a
mixture of clay, lime, and sand may be employed, either with or without
an admixture of "red ore "
or alkaline salts, these matters being mixed
with water to about the consistancy of cream; the pieces of metal are
to be dipped into or sprinkled over with this semi-fluid matter, and then
dried before they are charged into the furnace. The degree of car-
buration of the molten metal may be to some extent regulated by the
angle of the tuyeres and their height above the metal.
The several quantities or kinds of material to be fused in my improved
furnaces or apparatus, and be there converted into fluid steel, or into
fluid malleable iron, or into alloys of iron or mixtures of different kinds
of iron and steel, may consist of puddled iron or puddled steel in a

page_text: more or less granular or concrete state, or as puddled balls, if sufficiently
purified from phosphorus, or the puddled metal, either in the condition
of iron or steel, may be shingled and made into blooms or puddled bars,
and be cut into small or convenient pieces; but for the manufacture of
the better kinds of homogeneous malleable iron or cast steel, I how-
ever prefer to use finished iron or puddled steel bars, or bars of blistered
or cemented steel also cut into convenient lengths, which by preference
may be fused in crucibles in the improved furnace herein-after described,
although they may be fused in either of the different forms or modifi-
cations of my improved cupola or reverberatory furnaces. The materials
to be fused may also consist of iron or steel that has been obtained from
pig or crude iron, and wholly or partially decarburized and purified by
the action of nitrate of soda, or any analogous or other substances
containing or capable of evolving oxygen on coming in contact with
molten pig or crude iron, provided that the metal so obtained does not
contain so large a quantity of phosphorus, sulphur, or other impurities
as to render it unfit when fused for making into a marketable homo-
geneous malleable iron or cast steel.
The materials which I employ in my improved furnaces or apparatus
may also consist of any iron or steel in the form or condition of a
"metallic sponge," or of any metallic iron obtained by the deoxydation
of iron ore by cementation or otherwise, whether such sponge or metallic
iron does or does not contain an admixture of earthy or other substances,
or slags or substances which by fusion yield slags provided that it be
sufficiently free from carbon, sulphur, and phosphorus to render it
capable of producing by fusion a marketable quality of homogeneous
malleable iron or cast steel.
The materials which I employ may also consist of any wrought iron,
or steel scrap, such as the crop ends of iron or steel rails, also old or
worn out iron or steel rails, ingot ends, ladle skulls, and scrap Bessemer
iron aud steel, or other refuse steel and iron known generally as scrap,
provided that such scrap or refuse metal does not contain so much
phosphorous or other impurities as to render it unfit for the production of
a marketable cast steel or homogeneous malleable iron.
I would further state that in employing any of the aforesaid materials
an addition may be made thereto when desired of some good pig or
refined iron, or other carburet of iron or alloy of iron and manganese,
either for the purpose of forming a bath in which the other metals to be

page_text: fused are received, or for otherwise assisting their fusion or of adding
cheaply to the quantity of metal, or for the purpose of carburizing or of
deoxydizing it to the desired extent, for this last purpose, however,
spiegeleisen or ferromanganese is greatly to be preferred. I would also
remark that the addition of spiegeleisen or ferromanganese, when em-
ployed for the purpose of altering the degree of carburation of the metal
or for removing any oxygen therefrom, may be most advantageously
used after the molten metal has run out of the furnace by putting it in
a heated granular form or as a fluid into the ladle which receives the
charge of molten metal from the furnace. I would further remark that
the choice of the several kinds of metal before named for melting and
obtaining cast steel and homogeneous malleable iron will depend on
their known quality, on the local cost, and on the quality of the product
desired to be obtained. The manufacturer will for these several reasons
also employ them separately or mixed in such proportions às he may
think fit, or as their nature and properties may render necessary or
desirable. I also desire it to be understood that furnaces constructed so
as to have their temperature raised by the compression or condensation of
the gaseous products of combustion within them may also be employed in
fusing any of the more or less malleable kinds of iron and steel before
enumerated, and combining therewith pig iron or other carburet of iron
in such proportions as to form a sort of steely cast iron or mixed metal
suitable for casting "railway crossings" and wheels, bells, anvil blocks,
stamp heads, guns, mortars, projectiles, and other articles where a metal
stronger and harder than ordinary cast iron is required. My improved
furnaces may also be advantageously employed to melt any pig or other
carburet of iron to be afterwards converted into steel or malleable iron by.
the Bessemer process, and also in such cases when a carburet of iron
difficult of fusion is employed, and also in all cases where the melted
iron is required to be of a very high temperature.
I have herein-before described two modifications of the cupola furnace
in both of which the metal to be fused and the fuel employed to fuse it are
mixed and occupy one common chamber, I desire it, however, to be.
understood that my Invention also consists in melting steel or malleable
iron of any of the kinds or qualities herein-before enumerated when con-
tained in fire-clay, plumbago, or other crucibles, and also in fusing the
before-named metallic substances or either of them on the hearth of a
reverberatory furnace arranged for working with the products of com-
bustion under pressure, as in the cupola furnaces herein-before described.

page_text: be
In constructing furnaces in which crucibles are to be used, I prefer to
make the fuel chamber cylindrical, and to supply it with blast in a
similar manner to that already described in reference to the cupola
furnace. The upper part of the furnace is enlarged, and an annular seat
or space is formed around the fuel chamber, on which the crucibles are
placed; the furnace is covered with a dome-shaped roof, and several
small openings are left around the furnace for the escape of flame,
suitable doors being formed in the dome or roof for the removal of the
crucibles, the regulation of the pressure of the gaseous products and the
feeding of the fuel being arranged in a manner similar to that already
described in reference to the cupola furnace. Instead, however, of
removing the crucibles in order to empty them, they may if desired be
tapped from the exterior of the furnace while they still remain in place,
and so also the materials to be acted upon or fused therein may sup-
plied to them through openings in the outer wall of the furnace in a
similar manner to that by which a supply of materials is put into pots
or crucibles employed in making flint glass, or the dome or top of the
furnace may be made to turn round, and all the crucibles may in that case
be lifted out through a single opening, which is brought in succession
over each crucible. I desire it also to be understood that when crucibles
are employed in my improved furnaces, that both cast steel and
homogeneous maleable iron, and also any alloys of iron and manganese
that have been or may be made in crucibles contained in ordinary furnaces,
may in like manner be made in my improved furnaces, whether such cast
steel or homogeneous malleable iron, or alloys of iron with manganese or
other metals, be the result of simple fusion or be produced by the
chemical action or reaction of any materials put into them for that
purpose. In constructing furnaces in which the metal is to be fused on
the hearth of the furnace in the manner of reverberatory furnaces the
same general arrangement of fire chamber and tuyeres may be used as
that already described, the roof or arch of the furnace being a short
distance only above the hearth; the escape of gaseous matters at the
opposite end to the fire chamber, and the regulation of the pressure of
the confined gaseous products, and also the feeding in of the materials
and fuel being arranged in a similar manner to that herein-before
described in reference to the cupola furnace.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Bessemer in the Great Seal Patent Office
on the 10th May 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BESSEMER, of Queen Street Place, Cannon Street, in the City of
London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of November, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Henry Bessemer, Her special licence
that I, the said Henry Bessemer, my executors, administrators, and
assigns, or such others as I, the said Henry Bessemer, 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
THE MANUFACTURE OF CAST STEEL AND HOMOGENEOUS MALLEABLE IRON, AND IN
THE FUSION OR MELTING OF DIFFERENT KINDS OR QUALITIES OF IRON AND STEEL
AND THEIR ALLOYS, AND ALSO IN THE CONSTRUCTION AND MODE OF WORKING THE
FURNACES AND APPARATUS EMPLOYED FOR SUCH PURPOSES," upon the condition
(amongst others) that I, the said Henry Bessemer, 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.
NOW KNOW YE, that I, the said Henry Bessemer, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say:-
When cast steel and homogeneous iron are made by the fusion in
crucibles of blistered steel or bar iron, or when they are made from other
qualities or kinds of iron or steel free or nearly free from carbon, an
extremely high temperature is required for their fusion, and in the

page_text: ordinary air furnaces employed for this purpose a very large quantity of
expensive fuel is consumed in this melting process. Now therefore
one of the chief objects sought to be obtained by means of my
present Invention is a more rapid and less expensive mode of fusing
malleable iron and steel of different kinds, and obtaining cast steel
and homogeneous malleable iron therefrom. It will be understood that
in fusing substances requiring so extremely high a temperature as is
necessary to fuse malleable iron, that intensity of heat rather than
quantity is the condition essential to the successful working of furnaces
employed for that purpose, for a substance which requires 3,000 degrees
of temperature to produce complete fusion may be kept at a temperaturé
of 2,900 degrees for whole days in succession without becoming
thoroughly melted, when the mere addition of only 100 or 200 degrees
of heat would in that particular case have produced a complete fusion
of the substance in a very short period of time. This well-known law of
matter operates most disadvantageously in those cases where the fusing
point of the substance to be operated upon closely approaches the limit
of heat attainable by the combustion of fuel by a draught or blast of air
in ordinary furnaces. It is well known that atmospheric air and other
gaseous fluids in a heated state acquire a still higher degree of temperá-
ture by their compression or condensation into a smaller space than they
had previously occupied, such increase of temperature being in proportion
to their reduced bulk or to the number of atmospheres forced into the
space usually occupied by one. Now I avail myself of this last-named
property of gaseous fluids, and I construct furnaces of sufficient strength
to withstand an internal pressure equal to two or more atmospheres ;
and I retain in such furnaces the products of combustion under such an
pressure over that of the external air as will produce the high
temperature necessary for rapidly fusing inalleable iron and steel of any
kind or quality. I however desire it to be understood that I do not
propose by this means to generate a greater quantity of heat by the
combustion or iinion of a given quantity of carbon and oxygen than is
obtained by such means in well-constructed furnaces, for the com-
pression of the gaseous products of combustion within a furnace does
not generate heat, but merely concentrates into a smaller space and gives
greater intensity to the same quantity or number of units of heat as
would have existed in a more diffused state had not pressure been
applied, hence wherever the temperature produced by the combustion
of fuel in ordinary furnaces having a free escape to the chimney is
excess of

page_text: sufficient for any desired object, as, for instance, the evaporation of
water in steam boilers, a loss would be sustained by compressing the
gaseous products of combustion in such furnaces, for the amount of
engine power required to compress the gases would exceed the power
obtained from the increased quantity of steam generated in consequence
of such compression, all other conditions being equal; but when the
highest temperature produced in ordinary furnaces with a free escape is
actually less, or when it only by a small amount exceeds the temperature
absolutely required in any process, the case is entirely altered, and by
retaining the heated products of combustion in a highly condensed or
compressed state in a closed chamber or furnace I am enabled to
obtain a much higher degree of temperature within the furnace than
would result from the same expenditure of fuel if the said gaseous
matters were allowed freely to expand into the larger space they would
occupy under ordinary atmospheric pressure. Thus it will be seen that
the temperature produced in such furnaces will chiefly depend on the
amount of pressure maintained within the furnace in excess of the
pressure of the external atmosphere into which the gaseous products
of combustion escape. The temperature being always in relation to
the pressure is consequently under the complete control of the operator,
and he may choose between employing a temperature only a little above
the heat necessary to produce a complete fusion of the metal under
operation, in which case the rate of fusion would be slow, or he may
considerably increase the pressure and obtain a temperature so much in
excess of the actual fusing point of malleable iron or steel as to fuse
these substances with great rapidity, and impart to the fused metal so
high a temperature as to allow ample time for the diffusion of any alloy
through it if required, and at the same time admit of its being poured
without undue haste into a succession of moulds prior to the solidifica-
tion of any part thereof; but if the heat of the furnace is driven to an
excess with a view of economizing fuel or for the purpose of saving
time, it must be borne in mind that the wear and tear of the furnace
lining will be also increased, I therefore prefer a moderately rapid
fusion in preference to working at unnecessarily high temperatures; no
precise rule can, however, be rigidly laid down on this point, which
must be left to the judgment, skill, and experience of the workman; but
as a guide for him I may state that in a small furnace, using coke as
fuel, with a cold blast of 20 lbs. per square inch, and a pressure of
17 lbs. in the furnace over that of the external atmosphere, small

page_text: test pieces of cold wrought iron were fused with great rapidity; for
example, a piece of 2-inch square wrought-iron bar, 12 inches long,
weighing 13 lbs., was introduced cold into the furnace, and was com
pletely fused in 5 minutes; in the same small furnace 3 cwt. of
wrought-iron scrap was put in cold, and was poured fluid from the
furnace after an interval of 15 minutes; the furnace was then
working with an average internal pressure of 15 to
16 lbs. per
square inch in excess of the pressure of the external atmosphere. I
believe that a pressure of 20 to 30 lbs. over that of the external atto-
sphere will be found the most economical in practice, for it is probable
that if much greater pressure is employed it would raise the temperature
so high as to drive the iron rapidly off in the form of vapor, and
create great loss.
"
In order to distinguish this new system of fusing malleable iron and
steel from other methods that are known and practised, I have adopted
the term "high-pressure furnace for all the modifications of furnaces
working with the gaseous products of combustion blowing off from them
under great pressure, thus " high-pressure cupola furnace," "high-
pressure crucible furnace," and "high-pressure reverberatary furnace,"
will indicate by a common term the three classes of furnaces herein.
after described.
In carrying my said Invention into practical operation I employ
several modified forms of furnace, depending partly on the kind or
quality of metal to be fused in them, and partly on the kind or quality
of the intended product when fused, but however much the form and
details of the furnace are varied, I in all cases prefer to construct the
shell or outer case of the furnace of rivetted plate iron or steel after the
manner of constructing steam boilers, and having all the joints well
caulked and rendered air-tight, and of sufficient strength to resist safely
the number of atmospheres or pounds pressure per square inch up to
which it is proposed to compress the products of combustion within the
furnace, allowance being also made for the additional internal pressure
caused by the expansion of the lining of the furnace. In some cases,
however, cast iron may be employed for the outer shell of the furnace,
the several parts being securely bolted together and caulked at the
joints; but when using cast iron to form the shell of the furnace, I
prefer to employ strong tie-bolts and hoops of wrought iron or steel for
the purpose of retaining the several parts of the shell together in case of

page_text: a fracture of any part of the cast iron by expansion or internal pressure;
the several parts may be thus retained in position by the bolts or hoops,
so that in case of fracture the disastrous consequences of an explosion
will be avoided; so in like manner those furnaces the shells of which
are constructed of plate iron or steel may have their fittings made of
cast iron where the shape of the parts renders it desirable. The shell of
the furnace may be lined with good "Stourbridge fire-bricks," "Dinas
bricks," or with plumbago or other refractory material, or it may be
lined with ground ganister, as practised in lining the Bessemer con-
verting vessels now used for making steel. The extremely high
temperature of steel-melting furnaces render desirable the employment
of the most refractory materials for the linings of them. When I
employ plumbago as a lining for furnaces in which malleable iron
and steel or other carburets of iron are fused under pressure, I mix the
plumbago with as small a quantity of good fire-clay and water as will
render the plumbago sufficiently coherent to admit of its being rammed
or kneaded in a moistened state into place, and be retained there until it
is sufficiently dry to allow the furnace to be fired; the ramming in of
the plumbago may be effected in a manner similar to that employed to
line the "Bessemer steel converters" with moistened ganister; or the
plumbago mixed with clay may be formed into moulded bricks of the
same composition as employed in the manufacture of " plumbago
crucibles;" in either case it will be found more economical to partly line
the furnace with ordinary fire-brick, and to form an internal skin or
lining only of a few inches in thickness of the more expensive plumbago
composition. It is also desirable to use the ordinary fire-brick for the
external part of the lining, because it is a much slower conductor of
heat than plumbago, and will better protect the outer metal shell from
the effects of internal heat. When the cheapness of the iron or steel
produced is of more importance than the extreme purity or high quality
of the metal, I prefer to use the cupola form of furnace, consisting of an
upright fixed cylindrical or slightly conical vessel, with or without
boshes, and having a dome or covered top, through which the metal to
be melted and the fuel used for that purpose are admitted by an iron
door faced with fire-brick, but having externally a close metal fitting to
prevent the escape of flame and heated gases. The door may be circular
in form, and be supported on a strong moveable iron arm arranged with
a lever and cam, or with a worm wheel and screw, for the purpose of
securing the door firmly in place. The iron arm also carries an upright

page_text: cylinder of plate iron having a moveable bottom or grid; into this
cylinder the charge of fuel and metal is put, so that on the removal
of the door the cylinder is brought over the opening into the furnace;
the bottom or grid is then withdrawn, and the fuel and metal allowed to
fall into the furnace; after which the door is again moved over the
opening, and secured firmly in place by means of the lever or screw;
the blast should be shut off, or nearly so, during the charging of the
furnace, after which it may be again turned on, and the operation of the
furnace continued as before. In order to prevent an undue leakage
of flame and heated gases from between the feeding door and the
adjacent parts, and their consequent rapid destruction by the intense
heat of the flame, I make a hollow channel around the door or frame,
into which I convey steam or a blast of air, the pressure of which
exceeds the pressure within the furnace, so that whatever leakage
unavoidably occure, it is simply a leakage of steam or cold air inwards
instead of a leakage of flame outwards from the furnace. I also cool
the parts adjacent to all openings where necessary by the circulation of
water through suitable channels formed in those parts, and in furnaces
requiring a very large feeding door;-in lieu of using the lever or screw
arrangement, I secure the door in place by means of air, steam, or water
pressure acting on the door by means of a piston with a greater force
than is exerted on the door in an opposite direction by the pressure of
the gases within the furnace, and thus secure the door firmly on its
seat, the removal of the pressure thus applied by opening or reversing a
valve allows the door to be removed rapidly. There is also provided an
escape opening (or openings) for the products of combustion, the area
of which is capable of alteration and adjustinent by means of small
cylinders of fire-clay or other pieces of that material inserted in the
opening for the purpose of reducing its area. I prefer to use several
tuyeres for conveying the blast among the fuel,
and to make them of
fire-clay or plumbago, although "water tuyeres may be employed in
lieu thereof. Tha blast may be heated or cold, but I prefer to heat it
to a high temperature, and the pressure of the blast may range from
two to six pounds per square inch (more or less) over the pressure of
the confined gaseous products within the furnace; the pressure of the
latter will depend somewhat on the nature of the fuel employed and the
more or less refractory character of the metal to be fused, and for these
and other reasons it may range from a few pounds to several atmospheres

page_text: of pressure on each square inch of the interior surface of the furnace.
Some of the tuyeres employed direct the blast horizontally or upwards,
while others direct it downwards at about an angle of 30 to 45 degrees,
so as to heat as much as possible the lower part of the furnace and the
molten metal collected there, When the tuyeres which dip downwards
are intended to heat the metal on the hearth, I place them sufficiently
high up to cause the air to traverse a considerable depth of incandescent
fuel before reaching the surface of the metal; but if the tuyeres which
are directed downward are placed only a short distance above the level
of the fluid metal the blast will tend to refine or decarbonize the
metal, so that the quantity of carbon taken up from the fuel may if
desired be thus reduced. The horizontal or upward tuyeres may be used
simultaneously with them, or they may be shut off during the refining
operation. The tuyeres may also serve when required to convey any
solid fluid or gaseous matters into the furnace that may be found
desirable to act on the fuel or on the metal; or upon the impurities
contained therein, such as lime, carbonate of soda, chloride of calcium,
or other flux, as already known or practised with other furnaces and in
other processes of manufacturing iron and steel. The mode and
apparatus by which I prefer to convey any solid substances in the form
of powder along with the blast of air into the furnace is shewn in vertical
section at Figure 4, Sheet C. I introduce such matters in the close
vessel through a valvular opening x, which is closed by a bail y,
through which the screw z passes, and by means of which the valve is
held down the lower part of the vessel is conical, and is fitted on to
the main blast pipe by flange m with which it communicates; a
vertical spindle p passes up the centre of the vessel, and also passes
out through the stuffing box q formed in the cover n* of the vessel.
The spindle p carries at its upper end a drum 7, by means of which
rotatory motion may be communicated thereto; the lower end of this
spindle is provided with a screw blades, which reaches down into the
blast pipe a; the pipe u and stop-cock supply air to the upper part
of the vessel n, by means of which the pressure above and below the
powdered substances is equalized, so that the powder may fall down into
the blast pipe as quickly or slowly as desired, depending on the velocity
of the feeding screw, and be carried forward into the furnace and dis-
tributed among the lumps of incandescent fuel. A tapping hole is
also provided as usual in cupola furnaces, and a door for cleaning out
a

page_text: the slags and for repairing the furnace when necessary. There is also
provided a means of taking the cupola in two parts, for the purpose of
facilitating the lining of it with brickwork or for lining it with moistened
powdered materials to be rammed in around a suitable core or mould,
as practised in lining the Bessemer converter. The flanges which unite
the two parts I prefer to face in the lathe, so as to admit of their
forming a sound joint when bolted together. The upper portion of
the cupola may be lifted off with a crane, and will not require relining
so frequently as the lower part, which is acted on by the fused metal
and slags. The tapping hole I prefer to form by ramming loam around
a small truncated cone of well-burned fire-clay, which may be easily
driven into the furnace by a blow of the tapping rod, and thus open
the tap hole rapidly, and of a size dependent on the diameter of the
small end of the conical piece of clay. The metal when melted is thus
drawn off into a ladle in order to be transferred to moulds, as practised
in the casting of ignots or other masses of Bessemer steel. The addition
of spiegal eisen, or other alloys of iron if they be used, may be made
to the metal after it has been tapped from the furnace into the casting
ladle, or the metal may be used alone or be mixed with ordinary molten
pig iron in any desired proportion, and be used for casting a variety of
articles requiring a foundry iron of superior strength and hardness, or
it may be applied to such other purposes as its peculiar properties may
render it suitable for.
And in order that the mode of constructing and working the fixed
high-pressure cupola furnace may be fully understood, I have represented
the same on Sheet A of the Drawings hereunto annexed, where Figure 1
is a vertical section on the line A, B, of Figure 2; Figure 2 is a hori-
zontal section on the line C, D, of Figure 1; Figure 3 is a front elevation
of the furnace, and Figure 4 a plan of the upper part of the same; and
Figures 5 and 6, vertical sections of the escape aperture.
a is the outer shell of the furnace formed of strong plates of iron
rivetted and caulked air-tight at all laps and joints, and having gusset
pieces a to strengthen the bottom of it; b is an internal lining of fire-
brick, plumbago, ganister, or other refractory material; c, c, are fire-clay
tuyeres moulded square externally and having a round hole through them
for the passage of the blast; they are inserted through the square iron
frames d, which are secured by countersunk rivets to the shell a, and are

page_text: bevilled on the inside; the outer ends of the tuyeres c are enlarged or made
taper, and the space between these enlarged parts and the bevilled sides
of the frames d is caulked with iron cement (iron borings and sal-
ammoniac), so that the escape of gases from the furnace around the
tuyeres is prevented, and the pressure of the flanges e of the blast pipes f
against the enlarged ends of the tuyeres is also prevented from forcing
the tuyeres e into the furnace by reason of their enlarged ends and the
iron cement around them, while the blast-pipe flanges e, by being securely
bolted to the iron frames d, also prevent the internal pressure acting on
the ends of the tuyeres from driving them outward; the blast pipes f
are bolted to the main air trunk g by flanges f*. The air trunk g may,
if desired, be placed below the level of the floor, and in that case the
pipe g*, conducting air from any suitable blast engine, will be more
conveniently situated. Blast engines such as are generally employed in
the Bessemer process are well adapted for this purpose. An equilibrium
valve is placed in the main pipe g* conveniently near to the furnace, by
means of which the blast may be turned on or off or moderated from
time to time as desired. The feeding doors of these furnaces are so small
that it is necessary to provide a special means of entering the furnace
for relining the interior from time to time for the purpose of giving
convenient access to all parts of the interior. I divide the furnace into
two parts by massive angle flanges h, h, which are faced so as to form an
air-tight joint and are secured together by bolts and nuts, as shown at h°.
When the furnace is to be repaired the upper part may be lifted off with
a crane when the lower part will be readily accessible. A sinall
flange a¹ prevents the brick work of the upper part from being displaced
when lifted off. The furnace is provided with a spout i lined with loam
for conducting the metal into the casting ladle; a door is formed at
this part having only a small opening in it; by unbolting this door and
removing part of the lining the furnace may be cleaned out, the lining
being afterwards made up as in ordinary cupola furnaces; but I prefer
in making up the tap hole to insert a conical piece of well-burnt fire-
brick as shown at n, so that when the metal is to be drawn off from the
furnace the workman instead of having to drive a hole through the
solid material with a pointed bar will simply drive the cone n into the
furnace, and thus open a passage at once equal to the size of piece
detached; a small cross bar and screw (not shown in the Drawings) may
be employed to prevent the accidental blowing out of the cone, the bar

page_text: extending across the door j, and the screw pressing against the small end
of the cone 1.
It will be readily understood that in furnaces working under great
internal pressure that a special arrangement is necessary to secure the
feeding door against the leakage of the highly heated products of
combustion, and against a force, it may be of several tons, tending to
force it open, the arrangement also being such as to admit of the easy
and rapid opening and closing of the door for the admission of fuel and
metal. One of the modes which I employ for this purpose is shown
On the
applied to the upper part of the furnace delineated on Sheet A.
upper or crown plate or dome a* of the furnace I rivet a stout ring of
iron p, around which a hoop r is tightly shrunk on leaving a space
or annular channels, in which water circulates for the purpose of keeping
it cool; the water is supplied by the pipe o, and after circulating round
the ring p it escapes by the pipe ; the ring p is also further protected
by the lining of the furnace as shown at 6*. The fire-door frame u and
its covering plate is made by preference of wrought iron, the frame
having a conical interior in order the better to support the fire lump
the frame has a channel a formed around its exterior surface, over
which a hoop of iron w is shrunk, so as to complete the annular
passage; the lower surface of the frame u rests on the upper edge of
the ring b, both these faces being surfaced and made true; the under
side of the frame u has a small V-shaped groove or channel turned into
it and at about an inch apart; all round this groove small holes are
drilled which pass upward at an angle and connect the V-shaped grooved
channel with the annular space ; a pipe Q* conducts air from the
main blast pipe into the channel, which passes thence down the
numerous small drilled channels, and thus supplies air under pressure to
the V-shaped groove before named, now the pressure of the blast exceeds
the pressure of the gases within the furnace, consequently any imper-
fection in the fitting of the door frame down upon the upper rim p
of the furnace instead of allowing the highly heated gases to escape
and act destructively on the metal fittings, such gases are prevented
from escaping, because in case of imperfect fitting of the inetallic
surfaces the air under pressure in the V-shaped grcove will by reason
of its superior pressure force its way between the imperfect joint,
partly escaping into the upper part of the furnace and partly into
the external atmosphere, thus keeping the surface cool and the metal

page_text: work from injury. By this means it is found that so much only
of the fire lump as is exposed to the direct radiant heat of the fire
becomes red hot; this part of the lump which forms the upper side of
the narrow annular space left between it and the top of the furnace
lining not attaining a red heat in consequence of the slow leakage of
cold air inwards; it will be understood that steam in lieu of air may be
applied to this purpose, if desired, provided its pressure exceeds that of
the gaseous products within the furnace. In order to remove the door u
from the mouth of the furnace and readily replace it as required, I
employ a sort of crane arm which consists of two stout plate ironed
cheeks A, A, bolted to the crane post B, this latter is supported at its
lower end in a socket C bolted to the angle flange h. The upper end
of the crane post is supported by a strong bracket D having a hole
through it in which the crane post turns; at E is a moveable collar
fitting into a journal formed on the crane post for the purpose of pre-
venting the crane post from being lifted upward when pressure is applied
to the furnace door; between the cheeks A a piece of iron A* is firmly
bolted having a slot in the centre in which a worm wheel G is fitted.
This wheel and its elongated bosses G forms also a screw nut through
which the screw H works, a square part H° being formed on the upper
end of the screw to prevent its turning round, but not preventing its free
motion upward or downward through the block of iron A*, the holes
in which are of a diameter equal to the largest diameter of the screw, and
have no internal threads formed in them, the holes merely acting as
guides for the screw H, which carries on its lower end a plate J fitting
loosely inside a flanged ring K which is secured by bolts to the upper
plate of the furnace door. The object of the ring K and loosely fitting
plate J is to cause the door when lifted to be suspended in a horizontal
position. The freedom thus given to the door is for the purpose of
allowing it always to find its proper bearing on the ring p, the end of
the screw H then coming in contact with the upper plate ° of the
door will bind it firmly on its seat. For this purpose the handles L are
mounted on the shaft N, which also carries the worm P, this worm gears
into the worm wheel G, by the rotation of which the screw H is made
to rise and fall without rotation, carrying with it the door u. By the
compound screw motion thus arranged a very small exertion of force on
the handles will enable the door to be raised or lowered and retained in
position against the internal pressure of the gaseous products of the
furnace. The movement upward of the door need not exceed one quarter

page_text: of an inch to allow of its being moved on the crane from over the
opening of the furnace. Two stops (not shown in the Drawings) may
be used to prevent the crane arm from being moved too far in either
direction. For the purpose of facilitating the introduction of fuel and
metal into the furnace I employ a vertical feeding cylinder I made of
thin plate iron, which I secure by a strong iron bracket O to the crane
arm; the lower part of the cylinder I has a plate Q fitted to it; the
plate Q is keyed on to an upright spindle R supported by bearings S
attached to the side of the cylinder. The upper end of the spindle
having a handle T by means of which the plate Q is made to close or
open the bottom end of the cylinder. While the furnace is under blast
the workmen will put a charge of coke or other fuel into the cylinder
and along with it the scrap or other malleable metal to be fused, and
when the cylinder is filled the blast may be turned off, the handles L
put in motion, and the door u lifted sufficiently to allow the craue arm
to be moved round until the feeding cylinder is brought vertically over
the mouth of the furnace, a slight movement of the handle T will remove
the plate Q from beneath the cylinder, and allow all the fuel and metal
to fall at once into the furnace, the crane arm is then quickly moved
back into its former position, and the door is again forced down by
turning the handles, an operation in practice occupying from 30 to 40
seconds of time. Immediately after the closing of the furnace the
blast is iurned on and the operation of the furnace resumed, and at such
intervals as are found necessary the same oporation may be repeated.
In the plan, Figure 4, the crane arm is shown in the position it occupies
during the time that the fuel is being discharged into the furnace; the
plate Q is also shown removed from under it. I prefer to take the
supply of air to the door a from the main blast pipe at a point where the
equilibrium valve does not shut off the supply, the air will thus continue
to flow during the time the fuel is being supplied to the furnace, and
in the act of moving the door again over its seat the numerous jets
of air from the small drilled passages before named will blow away
with considerable force any small particles of fuel or other matter from
the surface against which the door fits. In order to admit of the motion
of the crane arm and to continue the connection with the air supply
the pipe q is taken to the top of the crane post and is there jointed to
the pipe q*; this piece of pipe q* is made of thin copper or pewter and
will spring sufficiently to allow of the slight rise and fall of the furnace
door. One of the chief peculiarities of this mode of working furnaces

page_text: under a high pressure of the gaseous products within them is the outlet
for the escape of flame, so different to the ordinary cupola furnace, where
the outlet is generally equal to the full diameter of the furnace; but
when working under pressure in one of these high pressure furnaces
I have found that an opening of 24 inches in diameter is sufficient for
a furnace whose transverse area is 572 square inches, the outlet being
about 144th part of the sectional area of the furnace. Thus it has been
found that with an internal pressure of 16 to 18 lbs. per square inch in
excess of the atmospheric pressure one square inch area of outlet may
be reckoned approximately as the area required for every 2 cwt. of coke
burned per hour in such furnaces.
a
On Sheet A of the Drawings I have shown the outlet of the furnace
at U. In its simplest form it consists of a square block of fire-brick
having a round hole in it of the desired size. It is made with a shoulder
externally which abuts against the interior of the casing a to prevent its
being forced out by internal pressure. A slight difference in the area
of the outlet materially effects the condition of the furnace, it is hence
desirable to have some means of altering it. In Figure 5 I have shown
a vertical section of an outlet block V, having two internal diameters
forming a shoulder, into this a small fire-clay cylinder W is put for the
purpose of contracting the area of outlet; and at Figure 6 a similar
outlet block is shown at X, having a small piece of moulded fire-brick Y
inserted therein, and, projecting sufficiently to be lifted out by pair of
tongs and be replaced by other pieces of different size. In both Figures
I have shown a flange plate % by which the outlet blocks are retained in
place; by unscrewing this flange plate the outlet block when too much
worn can be readily replaced by a new one. I would remark that the
amount of pressure up to which the gaseous products are kept within
the furnace will depend chiefly on the regulation of the pressure of the
blast, the escape aperture being also regulated so as to prevent the
pressure going below or getting above the point desired. In some
the escape of flame and heated matters may be regulated as as herein-
after more fully described by a loaded valve, the face of which is formed
of well burned fire-clay or other refractory matters, in which case a stop
may be provided so as to prevent the valve from entirely closing, but I
prefer that the escape should take place through one or more plain
apertures as above described as it may be thus more easily directed
in a manner so as effectually to utilize the heat of the escaping flame,
cases

page_text: which may be directed on to or into a bath containing the spiegeleisen
to be used at the end of the process, or the heat may be employed to
bring up the temperature of the metal and fuel previous to its being
introduced into the furnace; it may also be used for heating the blast, or
to generate the steam required to work the blast engine by causing the
heated products to pass under or through the tubes of an ordinary steam
boiler. Although I have described a fixed or stationary cupola furnace,
I nevertheless prefer in most cases to employ another modification of the
apparatus in which the cupola is suspended on trunnions, and is capable
of being tipped or moved thereon in a manner similar to the motion of
the ordinary Bessemer converting vessel, and whereby the metal may
be poured out of the furnace from an opening situated above the level
of the metal, and thus much of the trouble and inconvenience of tapping
the metal from the lowest part of the furnace is avoided, while it also
affords a convenient means of pouring out a sample of metal from time
to time and running out any accumulated slags. When the moveable
form of cupola is employed the blast may be carried through the
hollow axis or trunnions, or it may be conveyed through an arrange-
ment of jointed pipes; so in like manner steam or water used for cooling
any part of the furnace may be conveyed to it. In order that the mode
in which I construct high pressure cupola furnaces moveable on axes
may be fully understood I have represented the saine on Sheets B. and C.
of the annexed Drawings where Figure 1, Sheet B., is a vertical section
on the line A., B., of Figure 1, Sheet C., and Figure 2, Sheet B., is a front
elevation of the furnace; Figure 3, Sheet B., is a vertical section showing
the mode of admitting air and water through the trunnion or axis.
Figure 1, Sheet C., is a plan, and Figure 2, Sheet C., is a horizontal
section of the same furnace on the line C, D, of Figure 1, Sheet B. In
this modification of the cupola furnace the mode of constructing the
outer shell of rivetted plates, its lining of fire-brick, plumbago, or
ganister, and the modes of making and fixing the tuveres are all identical
with those already described in reference to the fixed cupola furnace
shown on Sheet A. of the annexed Drawings, as herein-before described,
so also it will be seen that the whole of the crown or upper part of the
moveable cupola furnace, and the crane arm, and crane post, furnace
door, worm and screw arrangement, and the feeding cylinder is precisely
like those before shown and described, and will therefore be understood
without again repeating a description of them. I have, however,

page_text: indicated the several parts of the apparatus which have been before
described by the same letters of reference as were used to denote them
on sheet A., so that no mistake may be made as to the nature or purpose
of any such parts; and in describing the several parts of the moveable
furnace which are peculiar to it and not before described, I have used
figures instead of letters of reference to denote such parts.
The cupola moveable on axes may be supported on strong standards
resting on the ground at each side, but as such standards would be more
or less in the way I prefer to support the enpola on the cantilevers 1
which project from a solid wall 2 forming part of a chimney or furnace
into which the gaseous matters are projected with considerable velocity;
the trunnions 3 and 4 project from a strong iron flanged band or
trunnion ring 5 extending around the cupola and to which the lower
angle flange is boited, and thus the two parts of the cupola are
suspended; the trunnion 3 extends beyond the plummer block 1* which
is formed on the end of the cantilever 1 and is provided with a stuffing
box and gland 6, through which the blast pipe 7 enters; this is best
seen in section at Figure 3, Sheet B.; a small pipe 8 passes through a
stuffing box formed at on the elbow of the blast pipe; the pipe 8 then
passes upward through the trunnion at 8 and is for the supply of
water to the ring p which forms the mouth of the furnace, the pipe 8
after passing some distance beneath the floor rises up and is connected
with an elevated reservoir for the supply of water to the ring p; after
circulating through the ring p the water descends by the pipe 11
through the axis 4, and by means of the pipe 12 is conveyed away. The
blast of air after passing through the trunnion 3 descends by means of the
pipe 13 into a cast-iron box 14 secured to the lower plates of the cupola;
from this box the pipes ff, convey the blast into the tuyeres before
described. In reference to the fixed cupola upon the upper part of the
brick work a stage is formed by the iron plate 16, which is supported by
upright standards 17, which rest on the cantilevers 1; the stage thus
formed is surrounded by a railing 18, and on it the workman is stationed
who supplies fuel and metal to the furnace; a similar feeding stage may
be employed for the supply of fuel and metal to the fixed cupola herein.-
before described, but which is not shown in the Drawings; a stage or
standing place should also be provided in both cases for the use of the
workman who operates the crane arm and opens and shuts the furnace
door when required. The notion of the vessel on its axes may be

page_text: effected by ordinary spur gearing in connection with a revolving shaft
slowly turned by engine power and capable of being thrown in and out
of gear or reversed by the ordinary means used for such purposes, or the
cupola may be moved by means of hydrostatic pressure as usually applied
for giving motion to Bessemer converting vessels. I have shown a spur
wheel 19 on the axis 4 of the cupola for this purpose, but have omitted
in the Drawings the hydrostatic apparatus, which is now well known
and understood. In cupola furnaces moveable on axes the ordinary
tapping hole is replaced by an opening of much larger size made in a
piece of fire-brick and shown at 20; this piece is fitted into a ring
21, leaving a conical space between the fire-clay and ring 21; this space
is caulked with iron borings, and not only serves to prevent the escape of
gaseous matters from the furnace, but a conical part being formed on
the fire-clay piece the latter is prevented from being forced out of the
furnace by internal pressure; the ring 21 is secured to the shell of the
furnace by countersunk rivets, and the front face of it is fitted to an
iron cover 23, by means of which the opening is closed, an arched-
shaped piece of iron 24 falls into two notches made to receive its outer
ends, and a screw 25 passes through a central boss in the arched
piece; by means of this screw and its cross handle the cover 23 is firnily
held in place, the end of the screw is formed into a loose cone, fitting
so as to give some play and allow the cover to fit freely in place, a false
ring or lip of fire-clay 26 is fitted in so as to cause the stream of metal
to flow clear of the iron surfaces when the cupola is tipped up for the
discharge of the metal, a rough lump of burned fire-clay 27 is put into
the opening to intercept the radiant heat on its passage to the cover, a
little loose sand may also be used, but I have not found it necessary.
I have before stated that some of the tuyeres may be made to dip so as
to direct the blast downward at an angle on to the metal; an example of
this form of tuyere is given at Figure 3, Sheet C., which shows a section
through the side of the cupola and tuyerc, the several parts being
indicated by the same letters of reference as are used to denote similar
parts on Sheet A. And here I would remark that the same general
node of working may be followed in fusing malleable iron and steel or
other carburets of iron in moveable cupolas, as described in reference to
the fixed one, except that instead of tapping all the metal at once the
moveable cupola admits of taking out tests or samples of metal from
time to time, if desired, and also of running off the slags as they accumu-
late. In order to facilitate the fusion into a liquid cinder all the im-

page_text: purities of the fuel, and the materials derived from the furuace lining,
lime, or other fluxes, heretofore employed for such purposes, may be used
in my improved furnaces in such quantities as the nature of the fuel
and other circumstances may render necessary, such fluxing materials
being introduced with the charges of fuel or conveyed into the furnace
by means of the blast in the manner herein-after described; the usual
door for cleaning out cupola furnaces after use, although not shewn in
the Drawings on Sheets B. and C., may be used, if desired, but it will be
found that by keeping the slags fluid by a sufficient quantity of alkaline
or other fluxes this opening may be dispensed with. I would also
observe that when malleable iron or steel is fused in cupola furnaces
there is a tendency to take up more carbon than is desirable in some
cases notwithstanding that the metal is coated with a vitreous flux as
hereafter described, it will therefore be preferable to also protect the
surface of the molten metal as it accumulates by allowing a little fluid
cinder always to remain floating upon it, and for the same reason to
employ as small a quantity of fuel as is found sufficient to generate the
necessary heat; for these reasons I prefer to employ the cupola furnace
in those cases where a slight degree of carburation of the metal is not
injurious, and to use the reverberatory furnace for the fusion of malleable
iron and the milder qualities of steel. The fuel I prefer to use is a
good hard coke or anthracite coal as pure and free from sulphur as can
be readily obtained. Charcoal or other fuel may however be employed,
and also lime or other fluxes hitherto known or employed for keeping
the slags or cinder in a fluid state, and although I prefer to employ solid
fue! it will nevertheless be obvious that in cases whore combustible
gases and air are employed as in the furnace known as "Siemens'"
regenerative gas furnace, or other gas furnaces or where liquid hydro-
carbons are to be employed in the fusion of malleable iron or steel or
melting of iron of any kind, this same system of increasing the tempera-
ture by confining the flame and heated products of combustion under
pressure within the furnace may be employed, the gaseous and liquid
fuels and air being forced by suitable force pumps into the chamber or
furnace where combustion takes place and where they are retained
under the desired pressure by means similar to those herein-before
described.
In carrying into practice that part of my Invention which relates to
the combustion of gases under pressure in what may be called a high-

page_text: pressure gas furnace I proceed as follows:-The gases to be employed
may be generated by the slow combustion of coal fuel on an inclined
grate or in close retorts, as generally practised in making coal gas for
illuminating purposes, to neither of which modes of producing gas do
I lay any claim; the gas thus or otherwise made may be received
in suitable gasometers. I employ a combined gas and air forcing
apparatus in order to force both the air and gas into separate receivers
under the desired amount of pressure; for this purpose I prefer to
use a blast engine constructed after the manner of the blast engines
in general use in the Bessemer steel process (and described in a Patent
granted to me on the 1st day of March 1860 and numbered 578), when
using this kind of blast engine I disconnect the pipes of one of the
air cylinders from the air vessel; and I connect the exhaust pipe of such
cylinder with the gasometer before named, and the delivery pipe of
such cylinder I connect with a gas receiver in which the gas is to be
compressed to the desired extent; the other air cylinder of the blast
engine may be as at present connected to an air receiver, so that by
the simple alteration of these pipes and the addition of a gas receiver
the blast engine becomes applicable to the condensation both of gas
and air in separate reservoirs under any desired amount of pressure.
The furnace which I prefer to employ for the fusion of malleable iron
and steel by the combustion of gases under pressure is of the rever-
beratory kind, and may be constructed after the manner of the several
kinds of gas furnaces known and in use, except that in all cases the entire
mass of brickwork or other refractory substances of which the furnace
is constructed must be enclosed in a strong iron casing rivetted and
caulked air-tight, and sufficiently strong to withstand the internal
pressure to be used therein. An example of this mode of casing a
reverberatory furnace is given at Figures 3 and 4 on Sheet D. of the
annexed Drawings, which is however arranged for the combustion
of solid fuel. In constructing similar furnaces for the combustion of
gases under pressure the fire chamber will not be needed and will
be replaced by the air and gas flues or by the compound or other
jet pipes that are used to convey or mix and distribute the gas and
air into such furnaces; the door for the admission of the metal to be
fused and the exit aperture for the escape of flame and other gaseous
products of combustion may be made in the manner hercin-before
described in reference to the feeding door and exit openings of the fixed

page_text: cupola furnace, or such modifications thereof and alteration of position
as the nature and arrangement of the several kinds of gas furnaces
known or in use may require. The quantity of air and gas admitted
to the furnace from time to time will be under the control of the
workman; for this purpose a slide valve or equilibrium valve is
fitted both to the gas and air main pipes, and by means of them
the supply of gas and air may be turned on or off or be regulated
as required. The gas and air may be used at their natural tem-
perature, or one or both may be heated in pipes, preferably made
of malleable iron or steel, or the gases may be heated under the
system known as "Siemens' regenerative furnace," in which case
the regenerators and all passages or flues employed for the passage of
the air and gases must be contained in a close case or jacket of
rivetted iron or steel, or made of cast iron and well bolted together,
and caulked and rendered air-tight when employing liquid hydro-
carbons for the fusion of malleable iron or steel in furnaces in which
the gaseous products of combustion are retained under pressure. I
prefer to use the reverberatory form of furnace, which may be con-
structed in the manner represented at Figures 3 and 4 on Sheet D. of
the Drawings hereunto annexed and herein-after described; in this
case I employ also solid fuel such as coke, and I cause the fluid bydro-
carbon to be taken in by the blast and be distributed among the pieces
of incandescent coke, and thus produce a large amount of flame. The
mode of introducing the fluid fuel into the blast pipe is shown in
vertical section at Figure 5, Sheet C. of the annexed Drawings, where a
is the main blast pipe leading to the tuyeres; the vessel is bolted by
a flange * to this pipe, the lower part of the vessel terminating in a
cone valve c, the spindle d of which is carried upward through a
suitable stuffing box e formed in the cover of the vessel; in the boss
of this cover at a screw thread is forined, and the screw is also formed
on the spindled so that the rotation of the spindle by means of the
hand wheel g will raise or lower the valve and regulate the velocity of
flow of liquid fuel into the blast pipe, along which the powerful blast
will carry it as a spray into and through the tuyeres. The vessel b
is provided with a funuel and cock for the supply of liquid fuel, and
also with an air pipe and cock *for the purpose of supplying air
under pressure to the upper surface of the fluid, and thus allow it to
flow by gravity into the blast pipe. In some cases it may be found

page_text: preferable to supply the fluid in jets at the tuyeres, the jet being in
the centre of the tuyere, in which case the employment of solid fuel
may be dispensed with as is now well understood, I however prefer
to employ it in conjunction with solid fuel for the purposes of my
Invention.
In order to protect the metal from an undue amount of oxidation
or carburation during its passage downward among the fuel and blast,
I prefer to coat the metal with a substance or compound capable of
fusing at a moderate heat and of forming a vitreous or glassy covering
to the metal for this purpose a mixture of clay, lime, and sand may
be employed either with or without an admixture of "red ore" or
alkaline salts, these matters being mixed with water to about the
consistency of cream; the pieces of metal are to be dipped into or
sprinkled over with this semi-fluid matter and then dried before they
are charged into the furnace. The bath of metal in the reverberatory
furnace may also be protected by a covering of fluid slag or cinder
by adding a small quantity of the before nained materials to the bath
during the fusion of the metal, or in lieu of this bottle glass (where it
can be cheaply obtained) may be used. The degree of carburation of
the molten metal may also be to some extent regulated by the angle of
the tuyeres and their height above the metal as before described.
The several quantities or kinds of materials to be fused in my improved
furnaces or apparatus, and be there converted into fluid steel or into
fluid malleable iron or into alloys of iron or mixtures of different kinds
of iron and steel, may consist of puddled iron or puddled steel in a
more or less granular or concrete state, or as puddled balls if sufficiently
purified from phosphorous, or the puddled metal either in the condition
of iron or steel may be shingled and made into blooms or puddled bars
and be cut into small or convenient pieces, but for the manufacture of
the better kinds of homogeneous malleable iron or cast steel I
however prefer to use finished iron or puddled steel bars or bars of
blistered or cemented steel, also cut into convenient lengths, which by
preference may be fused in crucibles in the improved furnace herein.
after described although they may be fused in either of the different
forms or modifications of my improved cupola or reverberatory furnaces.
The materials to be fused may also consist of iron or steel that has been
obtained from pig or crude iron and wholly or partially decarburized
und purified by the action of nitrato of soda or any analogous or other

page_text: substances containing or capable of evolving oxygen on coming in
contact with molten pig or crude iron, provided that the metal so
obtained does not contain so large a quantity of phosphorus, sulphur,
or other impurities as to render it unfit when fused for making into a
marketable homogeneous malleable iron or cast steel.
13
The materials which I employ in my improved furnaces or apparatus
may also consist of any iron or steel in the form or condition of a
"metallic sponge
or of any metallic iron obtained by the deoxidation
of iron ore by cementation or otherwise, whether such sponge or metallic
iron does or does not contain an admixture of earthy or other substances
or slags, or substances which by fusion yield slags, such as the
compounds of iron ore or oxides of iron and clay or other fusible
matters that are or may be made into bricks or lumps and cemented or
otherwise so treated as to convert such ores or oxides of iron into
metallic iron, provided that it be sufficiently free from carbon, sulphur,
and phosphorus as to render it capable of producing by fusion a
marketable quality of homogeneous malleable iron or cast steel.
The materials which I employ may also consist of any wrought-iron
or steel scrap, such as the crop ends of iron or steel rails, also old or
worn out iron or steel rails, ingot ends, ladle skulls, and scrap Bessemer
iron and steel or other refuse steel and iron, known generally as scrap,
provided that such scrap or refuse metal does not contain so much
phosphorus or other impurities as to render it unfit for the production
of a marketable cast steel or homogeneous malleable iron; I would
further state that in employing any of the aforesaid materials an addition
may be made thereto when desired of some good pig or refined iron
or other carburet of iron or alloy of iron and manganese either for the
purpose of forming a bath in which the other metals to be fused are
received or for otherwise assisting their fusion or of adding cheaply to
the quantity of metal, or for the purpose of carburizing or of deoxidizing
it to the desired extent, for this last purpose however spiegel eisen or
ferromanganese is greatly to be preferred; 1 would also remark that
the addition of spiegel eisen or ferromanganese when employed for the
for
purpose of altering the degree of carburation of the metal or
removing any oxygen therefrom may be most advantageously used after
the molten metal has run out of the furnace by putting it in a heated
granular form or as a fluid into the ladle which receives the charge of
molten metal from the furnace. I would further remark that the choice

page_text: of the several kinds of metal before named for melting and obtaining
cast steel and homogeneous malleable iron will depend on their known
quality, on the local cost, and on the quality of the product desired to
be obtained. The manufacturer will for these several reasons also employ
them separately or mixed in such proportions as he may think fit or as
their nature and properties may render uccessary or desirable.
I also desire it to be understood that furnaces constructed so as to
have their temperature raised by the compression or condensation of the
gaseous products of combustion within them, as herein described, may
also be employed in fusing any of the more or less malleable kinds of
iron and steel before enumerated and combining therwith pig iron or
other carburet of iron in such proportions as to form a sort of steely
cast iron or mixed metal suitable for casting railway crossings and
wheels, bells, anvil blocks, stamp heads, guns, mortars, projectiles, and
other articles where a metal stronger and harder than ordinary cast
iron is required.
My improved furnaces may also be advantageously employed to melt
any pig or other carburet of iron to be afterwards converted into steel
or malleable iron by the now well known Bessemer process, and also in
such cases where a carburet of iron difficult of fusion is employed, and
also in all cases where the melted iron is required to be of a very high
temperature.
I have herein-before described two modifications of the cupola furnace
in both of which the metal to be fused and the fuel employed to fuse
it are mixed and occupy one common chamber, I however desire it to he
understood that my Invention also consists in melting steel or malleable
iron of any of the kinds or qualities herein-before enumerated when
contained in fire-clay, plumbago, or other crucibles, and also in fusing
the before named metallic substances or either of them on the hearth of
a reverberatory furnace arranged for working with the products of
combustion under pressure as in the cupola furnaces herein-before
described.
In constructing furnaces in which crucibles are to be used I prefer to
make the fuel chamber cylindrical and to supply it with blast in a similar
manner to that already described in reference to the cupola furnace; the
upper part of the furnace is enlarged and an annular seat or space is
formed around the fuel chamber on which the crucibles are placed, the
furnace is covered with a dome-shaped roof and several small openings

page_text: are left around the furnace for the escape of flame, suitable doors being
formed in the dome cr roof for the removal of the crucibles, the
regulation of the pressure of the gaseous products and the feeding of
the fuel being arranged in a manner similar to that already described
in reference to the cupola furnace. Or the dome or top of the furnace
may be made to turn round, and all the crucibles may in that case be
lifted out through a single opening which is brought in succession over
each crucible.
I desire it also to be understood that when crucibles are employed in
my improved furnace that both cast steel and homogeneous malleable
iron, and also any alloys of iron and manganese that have been or may
be made in crucibles contained in ordinary furnaces, may in like manner
be made in my improved furnaces, whether such cast steel or homogeneous
malleable iron or alloys of iron with manganese or other metals be the
result of simple fusion or be produced by the chemical action or reaction
of
into them for that purpose.
any materials put
In order that the mode of constructing high-pressure crucible furnaces
employed for the fusion of malleable iron and steel or alloys of iron with
other metals may be fully understood, I have represented two methods of
effecting this object on Sheet C. of the Drawings hereunto aunexed, where
Figure 1 is a vertical section of a crucible furnace with a revolving
crown or dome; the outer shell a of the furnace is made of stout iron
or steel boiler plate securely rivetted and caulked at all laps and joints.
The bottom is further strengthened by stout T-angle irons rivetted
across it. The lower part of the furnace casing is sunk into the ground,
as shewn by the position of the floor line b around the upper part of
the shell a, the massive cast-iron ring c is secured by bolts through the
angle iron d. A channel or air passage eis cored in the ring c, and its
upper surface is truly faced in the lathe; a second cast-iron ring e is
also employed and forms a "skewback" in which the arch or done fis
built, the ring e is strengthened by shrinking on it a band of wrought
iron or steel g, and also by the webs e; the lower side of the rin ge
is surfaced truly in the lathe, and has a small channel n formed in it.
When the ring e rests on the ring c the channel n forms a close annular
passage, a great many small holes m are drilled into the channel c*, so
that when air from the main blast pipe is allowed to flow into the
channel c, it will pass through the numerous small holes m and occupy
the channel n, so that in case of any imperfection of the fitting together

page_text: of the rings e and c, the air under pressure in the channel c* will find
an escape between the rings flowing chiefly outward where there is only
the external atmospheric pressure to oppose it, but the air supplied
from the main blast pipe to the channel c* being under a somewhat
greater pressure than the confined gases within the furnace, a small
portion of the compressed air will pass inwards through such imperfect
joint, and effectually prevent the escape of any flame or heated gases,
and thus prevent the injurious action that might otherwise result from
such escape. The pipe which conveys air from the main blast pipe
into the channel c* is not shown in the Drawings, but it may convey
it into any part of that channel. This pipe should be provided with a
sluice valve, by means of which the quantity and pressure of air
flowing into the channel c may be so controlled that scarcely any air
is allowed to flow into the furnace. The dome or crown of the furnace
is formed externally of strong rivetted plates i secured to the ring e
by a wrought-iron angle ring j, and is lined with fire-bricks for other
refractory material, as herein-before described with reference to the
cupola furnaces. The lower part is also lined in a similar manner, as
shewn at ; that part of the furnace where the crucibles rest I
however prefer to make of large brick lumps, as they form a more
solid bed for the pots than ganister or other similar lining; at p, p, are
shown the orifices of two fire-clay tuyeres, of which several may be
used, and which are fitted into the furnace and to the outer shell, and
are also connected to the blast pipe in the same mauner as the tuyeres
shown in detail as applied to the cupola furnaces herein-before described.
A similar arrangement is also made for clearing out the slags and
residue of fuel, as shown in the cupola furnace, Figures 1 and 2,
Sheet A. of the annexed Drawings, small ash-pits being formed in the
floor for gaining access to this cleaning-out hole and to the tuyeres.
The ash-pits are covered with an iron plate or grating at the floor level.
An opening is made in the dome at k through which the crucibles q
are put in and removed by means of tongs, as usually practised in steel
melting furnaces. The metal to be melted in them may also be supplied
through this opening, and the pot lids put on after charging as usual
in other crucible furnaces, the crucibles are also placed on stands r as
usual. The fuel may be supplied when necessary through the opening k*.
by means of a funnels, shewn by dots, which is temporarily intro-
duced at the time of putting in the fuel, which I prefer to be good hard
coke. A flanged ring of metal t is rivetted to the crown plates i. This

page_text: ring is constructed in the same manner (except in so far as it fits
eccentrically on to the dome) as the ring or hoop p, shown at Figures
il,and 2, Sheet A. of the annexed Drawings. The opening * is intended
to be closed by a furnace door suspended from the crane arm moving
laterally on a crane post in suitable bearings attached to the shell of
the furnace, in the manner herein-before shewn and described in
reference to Figures 1 and 2, Sheet A., similar arrangements for the
admission of air to the joint and the flow of cold water for keeping
down the temperature of the ring t, as is also made in the ring p,
Sheet A. In the centre of the dome I provide an opening for the escape
of the gaseous products of combustion, which opening is constructed
as follows A stout ring of iron u is rivetted to the dome plates, and
to this ring is bolted the moveable flanged ring v, a piece of well burned
fire-clay w is fitted into the conical interior of the ring v; the size of
the opening in the piece of fire-clay w determines the quantity of gases
allowed to escape under any given pressure. By unbolting the ring v
different sized outlet pieces can be employed; a pipe x pendant from
the roof of the building and passing through it at its upper end will
convey away the flame and heated gases accompanied by a large quantity
of the surrounding air taken up as an induced current, and thereby
preventing the overheating of the pipex. In order to secure the dome
of the furnace in place during the period when the furnace is working
under pressure ten or twelve stout wrought-iron brackets A are bolted
securely to the ring c, and have strong steel capstan headed screws B
passing through the overhanging part of them before turning on the
blast to the furnace.
All these screws must be brought to bear firmly
on the upper side of the hoop, by which means the pressure within
the furnace is unable to raise the dome from its seat; so soon however
as the workman judges that the metal in his crucibles is in a state
of complete fusion he will shut off or moderate the blast for a short
time in order to cool down the pots as usual before "teaming." He
will then slacken all the screws B, raise the furnace door by means of
the screw apparatus, and swing it round so as to afford easy access to
the crucible immediately beneath the opening which he will lift out
with his tongs as usual. By then turning on a little blast to the
channel c*, the pressure of it acting on the lower surface of the ring
will cause the dome to either entirely float off its seat or by moderatiug
the pressure he can relieve it of so much only of the weight pressing
on the ring c as to allow it to be moved round with great freedom. Six

page_text: or more small guide rollers D are mounted on studs which project down-
wards from the ring e, the rollers run in contact with the inner face of
the ring c, and thus insure the proper position of the dome, on the
upper side of which several snugs or staples E are rivetted, into which
á staff F can be inserted for the purpose of turning round the dome of
the furnace, and thus giving access to each crucible in succession; the
crucibles may again be replaced when emptied, after which the furnace
may be supplied with fresh fuel, the crucibles charged with metal, and
the screws B tightened down, and the furnace door again brought over
the opening and secured there. The operation of the furnace may then
be continued under such an amount of internal pressure as is found
best adapted for the economical fusion of the particular quality of metal
employed.
At Figure 2, Sheet D., I have shown another modification of the
high-pressure crucible furnace, the outer shell G of which is constructed
with rivetted plates; and is lined throughout with fire-brick or other
refractory material H, the tuyeres and the mode by which they are
secured and connected to the blast pipe being the same as in the furnace
last herein described; in lieu however of the moveable dome for giving
access to the several crucibles I, four or other convenient number of
openings are made in the dome or crown of the furnace through
which the crucibles may be placed and removed when required, a pair
of tongs with the joint formed on one side of the claws will allow the
workman to place through the opening one crucible to the right hand
of the opening and the next one to the left, and finally he can place
one centrally between the other two and directly beneath the opening,
so that the four openings into the furnace will suffice for the placing
of twelve crucibles and also serve to introduce the fuel when required;
a lump of moulded fire-clay K having a ring inserted in it is placed in
the opening J and above it is placed a strong iron plate L having its
edge truly formed into a coñe; a flanged ring M is rivetted to the plates
of the dome and is made conical on its interior surface to fit the plate L
around which a little luting may be put as practised in keeping the
joints tight at the mouth of gas retorts; two strong staples N are
rivetted to the crown plates, through these staples the iron bar P is passed,
a screw O passes through this bar, which is employed to bind tlie plate L
firmly ou its seat; the openings Q; Q, for the escape of the products
of combustion may be placed on the sides of the furnace opposite to a
fite or chimney opening or they may be fitted into the crown of the

page_text: furnace as herein-before described in reference to the crucible furnace
with a revolving dome, and which latter form of crucible furnace I prefer
for the purposes of my Invention.
In constructing furnaces in which the metal is to be fused on the
hearth of the furnace in the manner of reverberatory furnaces the same
general arrangement of fire chamber and tuyeres may be used as that
already described, the roof or arch of the furnace being a short distance
only above the hearth, the escape of gaseous matters at the opposite
end to the fire chamber, and the regulation of the pressure of the
confined gaseous products and also the feeding in of the materials and
fuel being arranged in a similar manner to that herein-before described
in reference to the cupola furnace.
The mode of constructing high-pressure reverberatory furnaces for the
fusion of malleable iron and steel or other carburets of iron is represented
in Sheet 1), of the annexed Drawings, where Figure 3 is a longitudinal
vertical section on the line A, B, of Figure 4, and Figure 4 is a vertical
cross section on the line C, D, of Figure 3, shewing the fire chamber in
elevation, the feeding door and its appendages being omitted in this
view. a is the outer shell of the furnace formed of stout iron or steel
boiler plates well rivetted together and caulked air-tight at all laps and
joints; the end plates a" are further supported by stout angle gusset
plates a¹; the fire-box end of the shell a is in the form of a vertical
cylinder and is strengthened at bottom by stout T angles rivetted across
it at a² the upper part of the shell of the fire-box is strengthened by a
massive hoop of iron 6 into which numerous screwed studs care tapped
by means of which and the nuts fitted to them the dome or crown of
the shell is held securely on its seat. This mode of fixing on the crown
is adopted to facilitate the relining of the furnace from time to time;
the body of the furnace is oval in cross section; the oval part at a³ is
rivetted up to a corresponding opening in the cylindrical fire-box and
terminates at the angle flange d to which it is also rivetted; the end
piece a' has a similar angle flange e rivetted to it; this part of the furnace
is supported on a cast-iron standard f by which it is retained in position
when the central part as is taken away on a truck for the purpose of being
relined. There are also angle flanges g and h rivetted to the central part a',
all of which flanges d, e, g, and h are truly faced in the lathe so as to be
firmly bolted together and form a close air-tight junction of the different
parts of the furnace capable of resisting the great internal pressure of the

page_text: gaseous matters confined within the furnace, and at the same time
admitting the central part of the outer shell being removed, and thus
affords facility for relining the furnace when required, and which lining
may be readily effected by inserting a properly shaped wooden pattern
into the part to be lined and ramming in the moistened ganister around
it. The orifices of the tuyeres are shown at i, they are formed of fire-clay
or plumbago and are secured air-tight to the outer shell of the furnace
and connected to the tuyere pipes in the same manner as herein-before
described, and shewn with reference to the tuyeres and pipes employed
in the cupola furnace represented on Sheet A. of the annexed Drawings.
An opening for running out slug from the fire chamber j is shewn at k, it
may be stopped with loam as usual in cupola furnaces and be secured by
a covering plate / securely bolted on to prevent the loam from being
blown out. A slightly conical aperture m leads from the fire chamber to
the crown of the furnace where the door for feeding the fuel is situated;
a flanged ring of metal n is rivetted to the crown of the furnace having
a passages for the circulation of water formed in it, and also pipes r, r,
to convey water to and away from it; this arrangement and the con-
struction of the large circular door q are precisely the same as herein-
before shewn in detail as applied to the cupola furnace represented in
Sheet A. of the annexed Drawings, but instead of applying the screw and
worm wheel arrangement for opening the door, and by tightening it down
as before described, I employ the pressure of the blast or the pressure of
steam or water to act on a piston and thus exert the force necessary to
keep the furnace closed. This method is shown in elevation as attached
to the reverberatory furnace on Sheet D, and is also shown at Figure 6
on Sheet C. of the annexed Drawings, partly in section and in plan at
Figure 7, on the same Sheet, the same letters of reference are used'
where the parts are repeated in these Figures. t is the crane post with a
tubular passage t* formed in it; u is the footstep in which the crane
post moves; the footstep u is bolted to the shell of the furnace. A small
pipe v conveys air under pressure into it, and from which it is prevented
escaping by a stuffing box and gland; the air can however pass upward
through the small passage t*. The upper part of the crane post is
supported in a bracket piece w, which is rivetted by a flange w° to the
shell of the furnace and is formed into a shallow open cylinder t¹, two
arms forming part of the crane post casting also project upward and
carry between them the beam y, which is supported on a pin joint I.

page_text: At y another pin joint is formed; and by means of the links D the
beam is attached to the piston E; which is made air-tight by packing
rings in the usual manner. The opposite end of the beam y is jointed to
the upper side of the furnace door by the joint piece G and pin I. In the
lower part of the metal of the cylinder a small cock J is provided
having a very small way through it to prevent the too sudden passage
of air or other fluid into the cylinder, a small hole is drilled horizontally
through the metal forming the lower part of the cylinder and at right
angles to the axis of the cock J, so that the cock may act two ways;
that is, it may discharge air from beneath the piston when turned into
the position shewn in Figure 6 by the horizontal passage before referred
to; and by reversing it the air passing up through the crane post will be
conveyed beneath the piston, and by means of the pressure so exerted
the piston will rise and the beam or lever y will force the furnace door
firmly on to its seat; by this arrangement the opening and closing of
the furnace door may be rapidly effected with the labour only of turning
the small stop cock J, the piston requires to travel only about 1 inch
in order to lift the door sufficiently high to admit of its being moved
on one side, the feeding cylinder will thus be brought over the
opening m and discharge its fuel into the furnace; the feeding cylinder
is however omitted in Figures 3 and 4, Sheet D:, and in Figures 6 and 7,
Sheet C., but it is made and attached to the crane arm in the manner
shown in Figures 1 and 2, Sheet A.
I would also remark that although I have shown the arrangement for
closing the furnace door in the reverberatory furnace, and the screw and
worm wheel arrangement as applied to the cupola furnace, it will be
obvious that either mode may be employed in both kinds of furnaces:
The exit passage for the gaseous products of combustion shown at M
is moulded in fire-clay and well burned, a joint is formed between
it and the ring N with rust cement, with which the joint is caulked;
the ring N is securely rivetted to the end furnace plate and
to it is bolted the flanged collar P by means of which moveable
rings of fire-brick Q or other refractory materal are retained in
their position, and from which they may when necessary be removed
or exchanged for other rings, having a different area of outlet: In
addition to or in substitution of this mode of regulating the escape
of the gaseous products of combustion from high-pressure furnaces I

page_text: may
sometimes employ a valve formed of well burned fire-brick or other
refractory non-metallic substance. A valve so constructed is shewn
at Figure 8 on Sheet C., where a represents 'the upper portion of any
furnace to which it may be applied; 6 is a bevilled flanged ring rivetted
to the shell of the furnace; c is a hollow core of fire-brick, the large
end of 'which is capable of passing through the small part of the ring b,
the space being afterwards filled with "rust 'cement;" d is a part of 'an
iron bar fixed to any convenient part of the apparatus and serving as a
guide through which the rod e slides freely up and down; the lower end
of the rod is screwed into an iron box or frame f bevilled on the inside
for the purpose of receiving the fire-clay valve g, which is held in the
box by cement run in between it and the bevilled sides of the box;
a weight is placed on the top of the rod to regulate the pressure,
and a nut and collar at h will prevent the fire-clay surfaces from at any
time coming in contact and adhering together; although this valve will
not prevent the escape of some heated gases it will nevertheless prevent
the pressure from rising above the limit assigned. The reverberatory
furnace is provided with a tap hole shown by dots at M*; this hole
be stopped with a fire-clay cone as shown at Figures 1 and 2, on
Sheet A., as applied to the cupola furnace. I prefer to employ two
doors for charging on the metal to be melted; one may be placed on
each side of the furnace, or they may both be on one side of it, as
shown at m*, m*, Figure 3, Sheet i'. Figure 5 on this Sheet also
shows a horizontal section of one of these doors, and Figure 6 a front
elevation of the same; a strong iron frame n is rivetted by its flange to
the shell of the furnace; the outer face of this frame is faced and has a
deep groover formed in it, into which air from the main blast pipe may
be supplied by a small pipe having a stop-cock; upon it there are
projecting lugs p formed on the ring n, which form a hinge joint, and
at the opposite side of the ring are similar lugs q, through which the
moveable pin o is placed; an arm or jointed levers is fitted at one end
in between the lugs p, and thus forms a hinge joint on which the door
may be moved when the pin o is withdrawn. The door consists of
a circular iron box t, into which a fire-brick m¹ is fitted; the box t has
two studs u projecting from it which pass freely through the arms for
the purpose of supporting the door when it is thrown back on the
hinge joint. A powerful steel capstan-headed screw w passes through
the lever s, by means of which the door is forced tightly against the
grooved face of the frame n, after which air is allowed to flow into the

page_text: groove or channel r, under sufficient pressure to prevent the escape
of the flame or heated gases of the furnace. When employing such
furnaces for the fusion of malleable iron and steel or other carburets
of iron I charge on the materials by the doors last described, allowing
a small part of them to occupy the hearth or bed of the furnace and the
remainder I dispose on the "bank" or higher part of the bed in such
way as to intercept the flow of flame towards the outlet. The inalleable
metal may be fused alone or some good grey hematite or other pig
iron nearly free from sulphur and phosphorus may he employed, or in
lieu thereof some iron known as spiegel eisen may be put into the
hearth of the furnace and form a bath to collect the other fused
materials in, or the malleable part of the charge may when thoroughly
heated be pushed forward into the bath of molten carburet of iron,
but when steel, wrought iron, or malleable iron of any kind, or when
iron sponge or iron bricks are to be fused in such furnaces in the
absence of any pig iron I use a higher pressure than when pig iron
is used in admixture with them, in which case the pressure of the
confined gases may range conveniently from 30 to 50 lbs. pressure
per square inch, and after tapping such molten malleable metal from
the furnace into a casting ladle provided with a valve and stopper as
generally employed in the Bessemer process, I add molten or hot
granulated spiegel eisen or ferromanganese thereto in order to deprive
the fluid metal of any oxygen it may have taken up and to carburize it
to the extent desired. The fuel I prefer to use in the high-pressure
reverberatory furnace is a good hard coke, and in order to produce
a powerful flame I employ along with the coke a liquid hydrocarbon.
The creosote, petroleum, or other hydrocarbon may be supplied to the
blast pipe by means of the apparatus shown at Figure 5 on Sheet C.
of the annexed Drawings. I however desire it to be understood
that other fuel, such as anthracite or ordinary coal and dried wood
or charcoal, may be employed as found desirable.
Having thus described my Invention, and the manner in which
the same has been and may be carried into practical operation, I desire
it to be understood that I do not limit my claims to the precise details
and modes herein described of carrying the same into effect, provided
that the general and distinctive character of the said Invention and
the several parts thereof be retained. And in order that the extent
and limits of my said Invention may be more clearly ascertained I

page_text: desire to state that since the filing of the Provisional Specification
of my present Invention I have been made aware that it has been,
proposed by others to force air into the ash-pits of steam engine boilers
and other furnaces, in which the air so to be forced was in its escape
from the furnace proposed to be passed through a vessel of water and
through a valve. It has also been proposed to "trap" the chimneys
of steam boiler and other furnaces, and thus prevent the free escape
of the products of combustion, with the idea of thereby saving fuel.
It has also been proposed to cause the complete combustion of gases in
furnaces employed to melt pig iron for heavy castings by supplying air
to the ash-pit, and also in jets above the fuel by means of a blower,
a damper being used in the chimney to prevent the too free escape of
the gases, and causing the air to commingle more thoroughly with
the combustible gases; but I am not aware that any proposal prior to
the date of my present Invention has ever been made to so construct
furnaces as to enable them to withstand any considerable internal
pressure, nor that any proposal has been made to fuse malleable or
wrought iron and steel in furuaces where the products of combustion
are kept under high pressure, and the temperature of the furnace
thereby raised to the melting point of those refractory metals. I have
stated that I am aware of the proposals made prior to the date of iny
Patent, and above referred to, in order that it may be clearly understood
that I lay no claim thereto. But what I do claim as new and of my
own Invention is as follows:-
Firstly. I claim the melting or fusing of malleable or wrought iron
and steel or other similar carburets of iron difficult of fusion in a furnace
constructed so as to be capable of sustaining a high internal pressure by
compressing the gaseous products of combustion within the said furnace
which contains the said iron or steel to such a high pressure as will raise
the temperature of the said furnaces sufficiently high to fuse or liquify
the malleable or wrought iron and steel or other similar carburet of iron
difficult of fusion which is contained therein.
Secondly. I claim the melting or fusing of malleable or wrought iron
and steel or other similar carburets of iron difficult of fusion in furnaces
supplied with a blast or current of compressed air, and in which furnaces
the gaseous products of combustion are by reason of the smallness of the
escape aperture or apertures prevented from escaping from the furnace
until the pressure of such gaseous products contained in every part of

page_text: the said furnace is substantially in excess of one pound per square inch
above the external atmospheric pressure.
Thirdly. I claim determining the pressure of and the rate of discharge
of the gaseous products of combustion from furnaces employed for the
fusion of malleable or wrought iron and steel and other similar carburets
of iron difficult of fusion when working with the gaseous products of
combustion under high pressure by employing simple contracted escape
openings in lieu of valves or traps.
Fourthly. I claim the construction and employment of cupola furnaces
for fusing malleable or wrought iron and steel or other similar carburets
of iron difficult of fusion, such furnaces having a domed or covered top
with a door (for the admission of fuel and metal), which door is faced
with fire-brick or other refractory material, and is provided with a close
external metal fitting for preventing the escape of the gaseous products
of combustion confined under pressure within the furnace.
Fifthly. I claim the mode of opening or shutting the feeding door of
furnaces for melting malleable iron and steel or other similar carburets
ot iron difficult of fusion, and confining the gaseous products therein by
means of a compound screw apparatus constructed and applied in the
manner herein described.
Sixthly. I claim the arrangements for regulating or altering the
pressure of the gaseous products of combustion in furnaces employed
for the fusion of malleable or wrought irou and steel or other similar
carburet of iron difficult of fusion by means of moveable escape
apertures of different areas of outlet, and also by diminishing or in-
creasing the outlet by the insertion or removal from the escape aperture
of pieces of fire-clay or other refractory material as herein described.
Seventhly. I claim mounting on axes (through which air and water
may be passed) the cupola furnaces employed in the fusion of malleable
or wrought iron and steel and other similar carburets of iron difficult of
fusion when such fusion is effected by the accumulated heat resulting
from the retention of the gaseous products of combustion under high
pressure within the said furnace.
Eighthly. I claim the arrangement for preventing the escape of flame
and heated products of combustion through the joints of feeding or
other doors of furnaces employed under pressure, as described for the
fusion of malleable or wrought iron and steel and similar carburets of iron

page_text: difficult of fusion by means of currents of air or steam supplied to the
joint at a greater pressure than that of the confined gaseous products
within the furnace.
Ninthly. I claim cooling the metal fittings or parts adjacent to the
feeding or other doors or openings of furnaces employed under the
pressure of the gaseous products of combustion, as herein described,
to fuse malleable or wrought iron and steel or other similar carburets
of iron difficult of fusion by suitable channels formed in the parts to be
cooled through which a stream of water is passed.
Tenthly. I claim closing or securing the feeding or other doors of
furnaces employed under pressure of the gaseous products of combustion
for the fusion of malleable or wrought iron and steel or other similar
carburets of iron difficult of fusion by means of air, steam, water, or
other fluid pressure acting on a piston or plunger in connection with
such feeding or other doors.
Eleventhly. I claim the regulation of the pressure of gaseous matters
contained in furnaces employed in the fusion of malleable or wrought
iron and steel or other similar carburet of iron difficult of fusion by
means of a loaded valve faced with fire-brick or other analogous refrac-
tory material.
Twelfthly. I claim the fusion of malleable or wrought iron and stoel
or other similar carburets of iron difficult of fusion by the combustion of
carbonic oxide, carburetted hydrogen, or other combustible gases with
atmospheric air, such gas or gases and atmospheric air being forced into
and ignited in furnaces, the escape aperture of which is so small as to
cause the products of combustion to accumulate to high pressure within
the furnace so as to effect the fusion of said iron or steel.
Thirteenthly. I claim the fusion of malleable or wrought iron and steel
or other carburets of iron difficult of fusion by the combustion of liquid
hydrocarbons in high-pressure furnaces, the fusion being effected under
the accumulated heat arising from the compression and retention of the
gascous products of combustion under pressure within the furnace in
which the said iron or steel is fused.
Fourteenthly. I claim coating the surfaces of pieces of malleable or
wrought iron and steel or other similar carburets of iron difficult of
fusion with clay, lime, silica, or mixtures thereof, or other materials
capable of fusing into a glassy or vitreous covering, and thus protecting

page_text: their surfaces from oxidation or carburation, and the fusion of such
coated pieces in cupola or other furnaces where the gaseous products of
combustion are retained under pressure, as herein described.
Fifteenthly. I claim the fusion in crucibles of malleable or wrought
iron and steel or other carburets of iron or alloys of iron with other
metals, and the fusion of materials which yield malleable iron or steel
when melted, such crucibles being heated in chambers or furnaces in
which the gaseous products of combustion are retained under high
pressure as herein described.
Sixteenthly. I claim the fusion of malleable or wrought iron and steel
or other similar carburets of iron difficult of fusion in reverberatory
furnaces in which the gaseous products of combustion are retained under
high pressure, so that an accumulated heat is thereby obtained capable of
fusing the said iron and steel.
Seventeenthly. I clain in the construction of reverberatory furnaces
employed for the fusion of malleable or wrought iron and steel or
other similar carburets of iron difficult of fusion, the closely enveloping
the brickwork or other equivalent refractory lining of such furnaces
with a casing or jacket of rivetted iron or steel plates caulked at the
joints or made of cast iron bolted securely together, such casing being
sufficiently strong and tight at all points to withstand great internal
pressure.
Eighteenthly. I claim the fusion or remelting and heating of pig or
crude iron in high-pressure furnaces in which the gaseous products of
combustion are confined under high pressure as described, and the
conversion of such metal so melted and highly heated into malleable
iron or steel by blowing air through such metal according to the Bessemer
process, as is well understood.
Nineteenthly. I claim lining high-pressure furnaces employed for the
fusion of malleable or wrought iron and steel or other carburets of iron
under the pressure of the gaseous products of combustion contained
therein as described by ramming or pressing plumbago moistened with
water and fire-clay into the cavity or space to be lined.
Twentiethly. I claim the construction of high-pressure furnaces
employed in the fusion of malleable or wrought iron and steel or other
carburets of iron under pressure of the gaseous products of combustion

page_text: as herein described with tuyeres or pipes made of fire-clay or of plumbago
for the conveyance of a blast of air into such furnaces.
Twenty-firstly. I claim in the construction of reverberatory gas
regenerative furnace or other furnaces employing gaseous fuel the closely
enveloping of the fire-brick or other refractory lining of such furnaces
with a shell of plate iron or steel rivetted, caulked, and rendered tight at
all laps and joints or when such shell is made of cast iron well bolted
together and rendered tight at all joints, such iron, steel, or cast iron
shells being sufficiently strong and tight to withstand safely a great
internal pressure.
Twenty-secondly. I claim the general arrangement of the furnaces
and apparatus for the fusion or melting of iron and steel, substantially
as herein described.
In witness whereof, I, the said Henry Bessemer, have hereunto
set my hand and seal, this Tenth day of May, in the year of
our Lord One thousand eight hundred and sixty-nine.
HENRY BESSEMER. (L.S.)