IMPROVEMENTS IN THE MANUFACTURE OF MALLEABLE IRON AND STEEL AND IN THE APPARATUS EMPLOYED IN SUCH MANUFACTURE
Year: 1863

page_text: LETTERS PATENT to Henry Bessemer, of Queen Street Place, New Cannon
Street, in the City of London, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF MALLEABLE IRON AND STEEL AND IN THE APPARATUS
EMPLOYED IN SUCH MANUFACTURE."
Sealed the 8th March 1864, and dated the 5th November 1863.
PROVISIONAL SPECIFICATION left by the said Henry Bessemer at the
Office of the Commissioners of Patents, with his Petition, on the 5th
November 1863.
I, HENRY BESSEMER, of Queen Street Place, New Cannon Street, in the
City of London, do hereby declare the nature of the Invention for "IMPROVE-
MENTS IN THE MANUFACTURE OF MALLEABLE IRON AND STEEL AND IN THE
APPARATUS EMPLOYED IN SUCH MANUFACTURE," to be as follows: -
This Invention relates to the manufacture of malleable iron and steel from
pig or other carburet of iron by forcing atmospheric air into the molten metal,
and which is now generally known as the Bessemer process. When steel or
malleable iron is so made from pig iron a reverberatory furnace has generally
been employed to melt the crude metal, and it has been found that a loss in
the original weight takes place in such melting process, and also that some of
the carbon present in the iron is lost while the proportion of sulphurit contains
is augmented. Now, therefore, the first part of my said improvements has
for its object the lessening of the quantity of iron and carbon lost in the

page_text: melting process, and also the lessening ofthe quantity of sulphur absorbed, while
at the same time the quantity of fuel consumed in the melting furnace is
diminished. In order to carry into practical operation this first part of my
said improvements I employ a reverberatory furnace constructed in the usual
manner when for melting pig iron, excepting at that end of it which is nearest
the chimney, where it is provided with a second hearth or chamber having a
flat or nearly horizontal bottom through which the flames and heated products
of combustion pass on their way to the chimney. This chamber may, if desired,
be a simple elongation of the bank or part on which a portion of the metal
is to be melted; but I prefer to separate the melting chamber from the
second chamber by a dip in the roof so as to contract the aperture leading
from the first to the second hearth. The bed of the second hearth may, if
desired, be made moveable on wheels so as to facilitate the removal of the pig
metal and convey it to the converting vessel. As soon as that portion of the
metal occupying the first half or chamber is melted the metal occupying the
second one will have become highly heated and may then be put into the
converting vessel while still in a solid state and the molten part of the charge
be immediately run into the vessel with it; the converting vessel may then be
turned up and the forcing in of atmospheric air be proceeded with in the
usual manner. When steel is required the process may be arrested at that
stage when the desired amount of decarbonization has been arrived at, or
the metal may be wholly or nearly decarbonized and then have mixed with it
a further portion of carburet of iron in such quantity as will give to the
converted metal the degree of hardness or temper required. The white pig
iron known as franklinite, or the white pig iron known as spiegle eisen, mixed
with a small quantity of grey iron containing from 4 to 5 per cent. of silicon,
has been found most suitable for recarbonizing the converted metal and is now
It will be understood that the metal
generally employed for that purpose.
heated on the second hearth may be of the same quality as that melted on
the first hearth, or it may if desired be of some other kind or quality of iron
either in its crude or in a refined or partially refined state. And although I
prefer to economise fuel, by heating the unmelted portion of the metal in the
after part of the same furnace by means of the waste heat of such melting pro-
cess as herein-before described, it will nevertheless be understood that such
metal may be heated in any other suitable manner, or it may if preferred be
used in less quantity without being heated at all previous to its being put into
the converting vessel; in either case the addition of sulphur thereto, and the
loss of carbon therefrom, will be effected in a less degree than would result
from the fusion of the whole charge of metal in the reverberatory furnace as

page_text: beretofore practised. And further when it is desired to employ a carburet of
iron of a cheap or inferior quality along with the purer kinds of iron, such as
are obtained from spathose or hæmatite ores, I prefer to melt the better
quality of iron in a reverberatory furnace, and the inferior or cheaper kinds of
iron to be mixed therewith I first subject to a refining process after any
of the methods now in use for refining crude iron, or such inferior or cheaper
quality of iron may be purified by puddling such metal more or less so that
it may be brought nearly or quite to the point of refinement where the pro-
cess is generally stopped when making puddled steel, or it may be carried to
the extent usual when making wrought or malleable iron. This puddling or
partial puddling of the metal prior to its mixture with a carburet of iron in
the converting vessel may be performed by any known mode of puddling
mechanically, or it may be simply effected by hand labor in the usual way, in
either case the metal thus purified is to be put while in a heated state into
the converting vessel, and the rest of the charge, consisting of the molten
carburet of iron, is then to be run in with it and the process of conversion
by air proceeded with in the same manner as herein-before described when
heated pig iron is employed in a solid state along with the fluid metal.
The converting vessels mounted on axes, such as are now generally employed
for converting crude molten iron into steel or into malleable iron by the
Bessemer process, are generally heated to a very high temperature previous to
running the fluid metal therein, and it has been the general practice to con-
tinue the combustion of fuel in the vessel during the whole or a great part of
the time occupied in melting the charge of pig iron in a reverberatory furnace
which is intended to be converted therein. Now the object of the second part
of my said improvements is to economize the fuel so employed, and at the same
time to lessen the wear and tear of furnaces by employing the converting vessel
as a heating or melting vessel wherein the metal to be converted may be highly
heated while in the solid state, or be wholly or in part melted therein, and be,
without removal from the vessel, at once converted into malleable iron or steel.
When solid fuel is to be employed for this purpose, a fire may be lighted in the
converting vessel, and a moderate blast may be employed until it is well ignited.
The carburet of iron, whether.in the state of pig iron, or refined in any way, is
to be thrown upon the fuel, and the blast then urged until the metal is very
highly heated; the vessel is then to be turned into the position to receive some
molten carburet of iron, which may then be run in from any suitable melting
furnace or ladle. When this is done,any fuel still remaining unconsumed may
be raked out at the mouth of the vessel, which may then be urned up, and
the process of the decarbonization at once commenced by forcing upwards

page_text: through the fluid metal at:nospheric air, or other gaseous matters capable of
decarbonizing and raising the temperature of the metal. When treating crude
or pig iron that is highly carbonized, the heating of it in the converting vessel
may bé proceeded with until the sparks thrown out of the mouth of the vessel
indicate the commencement of fusion; at this stage of the process the vessel
may be partly turned down so that the drops of fused metal will not accumulate
overthe orifices of the tuyeres, but will occupy the same part of the vessel which
a charge of iron usually occupies when first run into the vessel. In order to
effect this fusion of the metal without any undue oxidation thereof, I prefer to
divide the tuyere box or make separate tuyere boxes so that the blast of air
employed to urge the fire may be conveyed only from those tuyeres that are
below the fuel when the vessel is partly turned down as before described. As
soon as the whole or a sufficient quantity of the charge of iron is melted I
prefer to remove as much as possible of the unconsumed fuel, after which the
vessel may be turned up and the conversion of the metal effected, the charge
of metal so treated being composed wholly of pig or refined iron, or it may be
composed partly of crude pig or other carburet of iron and partly of iron that
has been more or less refined by any known or adequate process previous to
its being put into the converting vessel. The fusion of the metal may be
effected by coke as much freed from sulphur as possible, or any purer fuel
capable of giving sufficient heat may be employed in lieu thereof, where con-
venient the gases from the blast furnaces may be employed, or carbonic oixde,
or carburetted hydrogen or mixtures thereof, may be employed to heat or melt
the metal in the converting vessel. In such cases I make a division of the
tuyere box or boxes in such a manner as will admit of streams of air and
streams of gas being directed into the vessel through the tuyeres in such
manner as to cause a complete combustion of the gases, but nevertheless
capable of such regulation as will prevent any undue loss of metal from
oxidation. Both the air and gases may if desired be employed in a heated state.
When thus applying gases through the tuyere separate communications may
be made for them through the axes of the vessel or a temporary communica-
tion may be established by a moveable pipe in connection with a gasometer.
My improvements also relate to the mode of setting tuyeres in converting
vessels employed in the manufacture of malleable iron and steel. As now
generally practised the tuyeres project upward from the tuyere box into the
vessel, and the spaces between them are filled up with a mixture of powdered
ganister "and water, having the consistency of batter; as much as 15
or 20 gallons are sometimes used, and it has been found to occupy an
inconvenient amount of time and expenditure of fuel to evaporate the water
"

page_text: from this semi-fluid matter. I therefore perforate the upper plate of the tuyere
box, and put on it felt or some woven fabric capable of allowing the water to
drain through; and I prefer to assist the extraction of the water by means of a
partial vacuum formed by an exhaust pump connected with the under side of
the perforated plate, an air-tight joint around the upper part of the tuyere box
being made by a turned ring of metal or by india-rubber, or other suitable
packing. A small exhausting pump may be connected to the tuyere box by a
moveable pipe, or the blast engine employed to force air into the metal may
have the valves so arranged as to render it capable of acting at any time as an
exhaust pump; in either case a receiver should be placed on the exhaust pipe
into which the water would flow instead of going into the exhaust pump. And
although I have explained how the drying of the material occupying the
spaces between the tuyeres may be facilitated by drawing off a large portion
of the water therefrom, I nevertheless desire it to be understood that this
application of the exhaust pump enables me to use a nearly or perfectly dry
material, such as coarse sand, "ganister," or other refractory material in a
state of powder, the pressure of air on the upper surface of the mass holding
it firmly in place until the heat and slags have sufficiently consolidated its
surface, and by which means the setting of tuyeres will be greatly expedited.
The loss of time occasioned by the drying of tuyeres set in the manner
herein firstly described, will be for the most part prevented by providing
several tuyere boxes or tuyere plates through which the tuyeres project; a
raised conical ring is to be placed around them, and the space between the
tuyeres rammed up with ground ganister or other material, and then baked
dry; the ring is then removed, and in that dry state they may be put into the
vessel,a hoop of iron, ora ring of brick work around the lower part of the vessel
defining the size of the opening left by the removal of a set of worn out
tuyeres. I prefer to make this opening of such a size as will admit the set of
dried tuyeres very freely, and leave a space of one or two inches around them,
which may be filled with "ganister" mixed with water running from the top,
or preferably by an opening on the outside of the tuyere box or vessel, or with
dry sand or other material. The tuyeres used in the manner herein-before
described sometimes break transversely, and the air getting into the crack
forces the upper end of the tuyere into the metal, and cause the lower part of
the tuyere to quickly wear away; to prevent this I make a somewhat larger
hole in the centre of the tuyere, roughened or corrugated throughout its
length, into this I insert an iron bolt or rod also roughened or formed with
rings on its surface; I pour some cement into the space formed between it

page_text: and the inside of the tuyere hole, so that the tuyere may be effectually held
in place, even if a fracture should take place.
In the manufacture of malleable iron and steel from crude iron or from
refined or partially refined iron by forcing atmospheric air into and below the
surface of the fluid metal, the air has hitherto been simply conveyed from the
blast engine or air vessel in a cold or in a heated state direct into the
converting vessel without otherwise altering the properties or gaseous con-
stituents of the air so employed, except in those cases where steam has been
mixed therewith; but I have found that the molten iron and the substances
incorporated therewith may be acted upon more or less advantageously by
charging or impregnating the air with the vapours of acids, alkaline, or saline
fluids,or hydrocarbons, or by passing the air through or between any solid sub-
stances capable of vaporizing or in part vaporizing or altering the properties
of the air, with a view to act upon or combine with the substances present
in the crude metal, and thus further refine, purify, or improve its quality;
the air and the fluid or solid substancos among which it is passed being kept
either in a cold or in a heated state, as may be found preferable. In carrying
this system into practical operation I prefer to line the lower part or the air
receiver with lead or with pottery ware, or with other substances not easily
destroyed by the fluids to be employed therein, the air from the blast engine
being conveyed through perforations situated below the surface of such fluid,
and being allowed to bubble up through it, and thus become more or less
altered in its properties and chemical constituents prior to its passage through
the tuyeres into the molten metal.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Bessemer in the Great Seal Patent Office on the
5th May 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BESSEMER, of Queen Street Place, New Cannon Street, in the City of London,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of November, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-seventh 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

page_text: Bessemer, my executors, administrators, and assigns, or such others as I, the
said Henry Bessemer, my executors, administrators, and assigns, should at an
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 MALLEABLE IRON AND STEEL, AND IN THE APPARATUS
EMPLOYED IN BUCH MANUFACTURE," 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 per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say :-
This Iuvention relates to the manufacture of malleable iron and steel from
pig or other carburet of iron by forcing atmospheric air into the molten metal,
and which is now generally known as the Bessemer process. When steel or
malleable iron is so made from pig iron, a reverberatory furnace has generally
been employed to melt the crude metal, and it has been found that a loss
in the original weight of metal takes place in such melting process, and also
that some of the carbon present in the iron is lost, while the proportion of
sulphur it contains is augmented. Now, therefore, the first part of my said
improvements has for its object the lessening of the quantity of iron and
carbon lost in the melting process, and also the lessening of the quantity
of sulphur absorbed, while at the same time the quantity of fuel consumed
in the melting furnace is diminished.
In order to carry into practical operation the first part of my said improve-
ments, I employ a reverberatory furnace constructed in the usual manner
when employed for melting pig iron, excopting at that end of it which is
nearest the chimney, where it is provided with a second hearth or chamber
having a flat or nearly horizontal bottom, through which the flames and heated
products of combustion pass on their way to the chimney; this chamber may,
if desired, be a simple elongation of the bank or part on which a portion of the
metal is to be melted, but I prefer to separate the melting chamber from the
second chamber by a dip in the roof, so as to contract the aperture leading

page_text: from the first to the second hearth. The bed of the second hearth may, if
desired, be made moveable on wheels, so as to facilitate the removal of the
pig metal, and convey it to the converting vessel.
In order that this combination of a melting furnace with a beating chamber
may be fully understood, I have given a longitudinal section of such furnace at
Figure 1 on the Sheet of Drawings hereunto annexed, where a is the fire-grate;
b, the bed of the furnace where the molten metal accumulates; and c, the
bank on which the charge of pig iron (intended to be melted) is placed; the
additional heating chamber d communicates with the melting chamber by an
opening at e, and with the chimney f by an opening at g. The chamber d
extends downward to the floor level, so that the carriage may be readily
h
moved in and out of the heating chamber; this carriage consists of an iron
frame i, mounted on 4 wheels, two of which are shown at j; the upper part
of the carriage frame is recessed for the purpose of retaining the fire-brick
floor, on which the metal to be heated is packed in such a manner as to
admit of the passage of the heated products of combustion from the melting
chamber to pass through or between it as shown at n,and whereby the metal
placed on the bed k may be highly heated during the fusion of the other
portion in the melting chamber. A pair of folding doors or a sliding door
made after the manner generally used in such furnaces will allow the carriage
to be moved in and out of the furnace when required. If it be preferred to
employ a solid bottom to the heating chamber, it may be made at the same
level as bed k, and a smaller door may in that case be provided for the removal
of the heated metal. In this arrangement for melting and heating metal it
will be understood that no more fuel will be necessary than is sufficient to
melt the charge of metal on the first hearth, and also that the decarbonization
and absorption of sulphur will be less in the unmelted portion of the charge
than it is in the portion that has undergone fusion. From one-third to one-
half the whole charge may be thus heated without being melted in the furnace,
but these proportions may be varied to suit the heat producing quality of the
iron when undergoing the converting process. As soon as that portion of the
metal occupying the first hearth or chamber is melted, the metal occupying
the second one will have become highly heated, and may then be put into the
converting vessel while still in a solid state, and the molten part of the charge
be immediately run into the vessel with it; the converting vessel may then be
turned up, and the forcing in of atmospheric air be proceeded with in the
usual manner. When steel is required, the process may be arrested at that
stage when the desired amount of decarbonization has been arrived at; or the
metal may be wholly or nearly decarbonized, and then have mixed with it a

page_text: further portion of carburet of iron, in such quantityaswill give totheconverted
metal the degree of hardness or temper required. The white pig iron known
as franklinite, or the white pig iron known as spiegel eisen, mixed with a
small quantity of grey iron containing from 4 to 5 per cent. of silicium, has
been found most suitable for recarbonizing the converted metal, and is now
generally employed for that purpose. This carbuetting or alloying metal may
be put into the converting vessel in a heated and unfused state, or in a melted
state, as generally practised; but I desire it to be understood that the heating
or melting of metal in the after part of the melting furnace to be used at or
near the conclusion of the converting process for the purpose of recarboni-
zing or alloying the converted metal, forms no part of my present
Invention, which in this respect relates only to the heating of a portion of
the charge of metal that is intended to be put into the vessel at the com-
mencement of the converting process.
It will nevertheless be understood that the metal heated on the second
hearth may be of the same quality as that melted on the first hearth, or it may,
if desired, be of some other kind or quality of iron, either in its crude or in a
refined or partially refined state; and although I prefer to economize fuel by
heating the unmelted portion of the metal in the after part of thesamefurnace
by means of the waste heat of such melting process, asherein-beforedescribed,
it will nevertheless be understood that such metal may be beated in any other
suitable manner, or the metal forming a portion of the charge may, if preferred,
be used in less quantity without being heated at all previous to its being put
into the converting vessel; in either case the addition of sulphur thereto, and
the loss of carbon therefrom, will be effected in a less degree than would
result from the fusion of the whole charge of metal in the reverberatory
furnace, as heretofore practised. And further, when it is desired to employ a
carburet of iron of a cheap or inferior quality, such as is usually made from
the black-hand or argillaceous ores along with the purer kinds of iron, such as
are obtained from spathose or hematite ores, I prefer to melt the better
quality of iron in a reverberatory furnace, as heretofore generally practised,
except in those cases where such fluid iron from blast furnaces can be con-
veniently obtained, and the inferior or cheaper kinds of pig iron to be mixed
therewith, I first subject to a refining process after any of the methods now
in use for refining crude iron, or such inferior or cheaper quality of iron may
be purified and refined by puddling such metal more or less, so that it may be
brought nearly or quite to the point of refinementwheretheprocessisgenerally
stopped when making puddled steel; or it may be carried to the extent usual
when making wrought or malleable iron; this puddling or partial puddling

page_text: of the metalprior to its mixture with a carburet of iron in the converting vessel
may be performed by any known mode of puddling mechanically; or it
may
be simply effected by hand labor in the usual way; in either case the metal
thus purified or refined is to be put, while in a heated state,into the converting
vessel, and the rest of the charge, consisting of the molten carburet of iron, is
then to be run in with it, and the process of conversion by air proceeded
with in the same manner as herein-before described when heated pig iron
is employed in a solid state along with the fluid metal.
In carrying into practical operation this part of my said Invention, the
inferior or cheaper kinds of iron, such as are produced from the black-band
ironstone, or from argillaceous and other ores of iron, may be employed in
combination with other and purer carburets of iron in the production of steel
or malleable iron of a quality for which such cheap or inferior iron is not so
well adapted in its unrefined state; and although the puddling or partial
puddling of such cheap or inferior kinds of iron may be performed by manual
labor in the ordinary way, it will be obvious that the metal may be more
cheaply and advantageously refined in large quantities by some of the well-
known arrangements of mechanical puddling apparatus, in which that process
is effected in a revolving cylinder or otherwise. I prefer that the metal should
be carried to about that stage of the puddling process at which it has the
general properties of steel, or it may, if preferred, be carried on until its
complete decarbonization is effected; in either case it may be roughly balled
up for convenience of removal while still in a heated state to the converting
vessel; or it may, if preferred, be mixed with the molten iron in a loose
granular state, without balling it up. The molten crude iron, which I prefer
to employ in combination with the puddled metal, is highlycarburretted, being
of the quality known as No.1,since this quality of metal will furnish sufficient
heat to melt down a considerable quantity of the puddled metal, especially
if the latter be not entirely decarbonized, and is put into the converting vessel
in a highly heated state, from one-fourth to one-half, more or less, of the
puddled metal may be employed at the discretion of the manufacturer, but
this may be much varied.
The converting vessels, mounted on axes such as are now generally
employed for converting crude molten iron into steel or into malleable
iron by the Bessemer process, or generally heated to a very high tempe-
rature previous to running the fluid metal therein, and it has been the
general practice to continue the combustion of fuel in the vessel during the
whole or a great part of the time occupied in melting the charge of pig-
iron in a reverberatory furnace, which is intended to be converted therein.

page_text: Now the object of the second part of my said improvements is to economize
the fuel so employed, and at the same time to lessen the wear and tear of
furnaces by employing the converting vessel as a heating or melting vessel,
wherein the metal to be converted may be highly heated while in the
solid state, or be wholly or in part melted therein, and be, without removal
from the vessel, at once converted into malleable iron or steel. When solid
fuel is to be employed for this purpose a fire may be lighted in the convert-
ing vessel, and a moderate blast may be employed until it is well ignited.
The carburet of iron, whether in the state of pig iron or refined in any way,
is to be thrown upon the fuel and the blast then urged until the metal is
very highly heated.
This mode of heating the metal may be readily understood, by reference to
the annexed Drawings, where Figure 2 is a vertical section of a converting
vessel, such as is now generally employed in the manufacture of steel. It will
be perceived that the fuel m,lying over the numerous orifices of the tuyeres ",
will be highly ignited by the powerful blast issuing from them, and con-
sequently the lumps of metal p, will acquire a very high temperature by the
time the vessel has been sufficiently heated. It is desirable to use no more
fuel than will suffice by its combustion to heat the vessel and the metal
sufficiently, or there may be some difficulty in removing the unconsumed fuel
which floats on the surface of the metal that is afterwards put in. When the
metal is sufficiently heated the vessel is then to be turned into the position to
receive some molten carburet of iron, which may then be run in from any
suitable melting furnace, blast furnace, or ladle. When this is done any fuel
still remaining unconsumed may be raked out at the mouth of the vessel,
which may then be turned up, and the process of decarbonization at once
commenced by forcing upwards through the fluid metal atmospheric air or
other gaseous matter capable of decarbonizing and raising the temperature
of the metal. When treating crude or pig iron that is highly carbonized, the
heating of it in the converting vessel may be proceeded with until the sparks
thrown out of the mouth of the vessel indicate the commencement of fusion;
at this stage of the process the vessel may be partly turned down, so that the
drops of fused metal will not accumulate over the orifices of the tuyeres,but will
occupy the same part of the vessel which a charge of iron usually occupies
when first run into the vessel. This position of the vessel and its contents is
shown in vertical section at Figure 3 on the annexed Sheet of Drawings. In
order to effect this fusion of the metal without any undue oxidation thereof,
I prefer to divide the tuyere box, or make separate tuyere boxes, so that the
blast of air employed to urge the fire may be conveyed only from those tuyeres

page_text: that are below the fuel when the vessel is partly turned down, as before
described.
In Figure 3 of the Drawings annexed the tuyere box r is shown with a
division plates formed therein, so that the blast of air may be admitted to
each compartment of the tuyere box, when necessary, by pipes communicating
with it at t and u, but when the fusion of the metal commences, the vessel
should be turned on its axis until it assumes the position shown in Figure 3,
and the supply of air should then be turned off by a suitable valve from the
pipe t, and consequently be prevented. from passing through the tuyeres v,
where there would be little or no fuel for it to act upon, the communication
with the blast engine is, however, still to be kept up by means of the pipe u,
which enters the lower part of the tuyere box, and admits a powerful blast
through the lower set of tuyeres w, and will act on the fuel which will have
fallen in front of these tuyeres somewhat into the position shown at x, the
flame thus produced will rapidly bring about the fusion of a part or the whole
of the charge of metal shown at y, the fused portion of which is also shown
accumulating at Z, where it will be still subjected to the action of the flame
and heated products of combustion, and its temperature be thus kept up
although it is at toɔ low a level to rise above the orifices of the tuyeres. As soon
as the whole or a sufficient quantity of the charge of iron is melted, I prefer
to remove as much as possible of the unconsumed fuel, which will be found
floating on the surface of the fluid metal,and nearly on a level with the mouth
of the vessel, the fuel may be raked forward and allowed to fall out on to the
floor of the casting pit, and if the blast be turned on at full pressure from the
upper set of tuyeres, while the vessel is still in the position shown in Figure3,
any remaining portions of the fuel will be blown out of the mouth of the
vessel, after which the vessel may be turned up and the conversion of the
metal effected by forcing atmospheric air into and below the surface thereof,
as now generally practised; the charge of metal so treated being composed
wholly of pig or refined iron, or it may be composed partly of crude, pig, or
other carburet of iron, and partly of iron that has been more or less refined
by any known or adequate process previous to its being put into the converting
vessel. The fusion of the metal may be effected by coke as much freed from
sulphur as possible, or any purer fuel capable of giving sufficient heat may be
employed in lieu thereof, where convenient the gases from the blast furnaces
may be employed, or carbonic oxide or carburetted hydrogen or mixtures
thereof may be employed to heat or melt the metal in the converting vessel
in order to prepare such metal for conversion. I, however, desire it to be
understood that I lay no claim in these in part recited Letters Patent to the

page_text: heating of the interior of the converting vessel, by the waste gases of the blast
furnace, or by other gaseous products when conveyed into the vessel by an
opening made in the side of it for that purpose; but I employ jets of com-
bustible gases and atmospheric air conveyed into the vessel through the tuyeres,
for the purpose of heating or melting in the converting vessel a portion or
the whole of the metal that is to be converted therein. In such cases I
make a division of the tuyere box or boxes, in such a manner as will admit of
streams of air, and streams of gas being directed into the vessel through the
tuyeres in such manner as to cause a complete combustion of the gases, but
nevertheless capable of such regulation as will prevent any undue loss of
metal from oxidation. Both the air and gases may, if desired, be employed
in a heated state, and when thus applying gases through the tuyeres, separate
communication may be made for them through the axes of the vessel, or a
temporary communication may be established by a moveable pipe in connection
with a gasometer.
And in order that this mode of heating or melting metal by gas in the
converting vessel prior to the conversion of such metal may be fully under-
stood, I have shown, at Figure 4 of the annexed Drawings, a vertical section
of a tuyere box having a division plate A therein; as before referred to; this
plate is provided with a series of conical openings which are placed opposite
to a similar set of openings formed in the upper part B* of the tuyere box B
The tuyeres C have an elongated part at C* which passes through the
openings in the plate A, and is kept air-tight therein by ramming some clay
into the joint around the lower end of the tuyere. Every alternate hole in
the tuyeres should have another hole C¹ made in it at right angles to the
main passage which passes longitudinally through it, the bottom ends of each
such passage being plugged with clay, whereby all such passages through the
tuyere may be made to convey gas from the upper or gas chamber D of the
tuyere box into the vessel, but can convey no air from the lower or air.
chamber E in consequence of the lower ends of such passages being plugged,
while all those longitudinal passages in the tuy ere which have no cross passage
communicating with the upper or gas chamber D, and are open at their lower
ends, will convey atmospheric air into the vessel. By this arrangement, each
tuyere will somewhat resemble an "Argand" gas burner with air and gas
issuing from alternate holes around its outer edge; a horizontal section view
of such a tuyere is shown at Figure 5. This mode of supplying air and gas
in separate streams through the tuyeres into the vessel will produce an intense
combustion, and rapidly heat or melt the metal therein, the quantity of air
and
I gas supplied for this purpose being regulated by valves on their respective

page_text: supply pipes, as well as by the amount of pressure under which the air and
gas are supplied.
My improvements also relate to the mode of setting tuyeres in converting
vessels employed in the manufacture of malleable iron and steel. As now
generally practised, the tuyeres project upward from the tuyere box into the
vessel, and the spaces between them are filled up with a mixture of powdered
6 ganister " and water having the consistency of batter; as much as 15 or
20 gallons are sometimes used, and it has been found to occupy an incon-
venient amount of time and expenditure of fuel to evaporate the water from
this semi-fluid matter. I therefore perforate the upper plate of the tuyere box,
and put on it felt or some woven fabric capable of allowing the water to drain
through, and I prefer to assist the extraction of the water by means of a
partial vacuum formed by an exhaust pump connected with the under side of
the perforated plate, an air-tight joint around the upper part of the tuyere
box being made by a turned ring of metal, or by india-rubber or other suitable
packing. A small exhausting pump may be connected to the tuyere box by
a moveable pipe, or the blast engine employed to force air into the metal may
have the valves so arranged as to render it capable of acting at any time as
an exhaust pump; in either case a receiver should be placed on the exhaust
pipo, into which the water would flow instead of going into the exhaust pump.
And although I have explained how the drying of the material occupying the
spaces between the tuyeres may be facilitated by drawing off a large portion
of the water therefrom, I nevertheless desire it to be understood that this
application of the exhaust pump enables me to use a nearly or perfectly dry
material, such as coarse sand, "ganister," or other refractory material in a
state of powder, the pressure of air on the upper surface of the mass holding
it firmly in place until the heat and slags have sufficiently consolidated its
surface, and by which means the setting of tuyeres will be greatly expedited.
It has hitherto been the general practice to so connect the tuyere box to
the converting vessel as to leave a space between them for the free escape of
air should any portion leak out by the side of the tuyeres, a provision which
it is important to retain ; when, therefore, it is intended to apply the principle
of exhaustion to the removal of water from the semi-fluid materials run in
between the tuyeres, I so arrange the closing up of this space that when the
drawing-off of the water has been effected the space for the escape of air
from leakage may again be readily opened.
The mode by which I effect this object will be better understood by
reference to the Sheet of Drawings hereunto annexed, where Figure 6 is a
vertical section through the tuyere box and a portion of the lower part of the

page_text: converting vessel. 1 is the tuyere box secured by studs 5 to the lower part
of the couverting vessel, which studs pass through the plate 4; this plate
is secured to the tuyere box at several places by bolts. The plate 4 is per-
forated, and has upon it a piece of felt or wire gauze or other pervious woven
fabric, in which holes are cut for the tuyeres 6 to pass through, and which
will prevent the solid particles of ganister or sand from passing through the
perforations in the plate 4; although it will allow the passage of water from
the semi-fluid mass, shown at 7, and which fills the spaces between and
around the tuyeres, the outside of the tuyere box is turned truly to fit the
inside of the ring of metal 8. The upper part of this ring is made true, or it
may be covered with some elastic material, so as to make a nearly close or
air-tight joint with the plate 4; there are vertical ribs at intervals formed
around the inside of the upper part of the ring 8, so as to guide it up and
down steadily on the outside of the tuyere box,and which ribs do not obstruct
the communication between the space 10 and the annular space 9 which
surrounds the tuyere box, and into which space a pipe 11 is fitted; this pipe
may be unscrewed so soon as the withdrawal of the water is effected. The
ring 8, when in use, is forced upward in contact with the plate 4 by several
screws 12, which pass through lugs 13 cast on the tuyere box; the with-
drawal of these screws will allow the ring 8 to sink down on to the lugs 13,
and again open the space 10, so that any air that may leak from the tuyere
box around the tuyeres may escape freely.
The loss of time occasioned by the drying of tuyeres set in the manner
herein firstly described will be for the most part prevented by providing
several tuyere boxes or tuyere plates through which the tuyeres project; a
raised conical ring is to be placed around them, and the spaces between the
tuyeres rammed up with ground ganister or other material, and then baked
dry. The ring is then removed, and in that dry state they may be put into
the vessel, a hoop of iron or a ring of brickwork around the lower part of the
vessel defining the size of the opening left by the removal of a set of worn
out tuyeres. I prefer to make this opening of such a size as will admit the
set of dried tuyeres very freely, and leave a space of one or two inches
around them, which may be filled with "ganister" mixed with water run in
from the top, or preferably by an opening on the outside of the vessel, or
with dry sand or other material.
This mode of building up and baking a set of tuyeres in a tuyere box pre-
vious to putting them into the converting vessel will be better understood by
reference to the Sheet of Drawings hereunto annexed, where Figure 7 is a
section of a tuyere box and the lower part of the converting vessel so arranged

page_text: as to carry out this part of my said Invention, the tuyere box having the
tuyeres built up and ready for inserting into the vessel is shown in elevation
at Figure 8. The tuyere box G is, as usual, provided with a plate H with
an interval for the escape of air in case of leakage; to the plate H a conical
ring of thin iron I is fixed and serves to retain the material which occupies
the space between and around the tuyeres; this material, which consists
generally of ground ganister moistened with water is to be rammed into the
space included within the ring I, and is also to be carried up at the same
angle as high as the top end of the tuyeres, aad it may then be slowly dried
or baked; when inserted in the lower part of the vessel a space J will be
left, which is to be filled with a semi-liquid mixture of ganister and water,
which may be run in in the way generally practised when setting tuyeres;
the water from this small portion will be soon absorbed by the dry sur.
rounding materials, and the vessel will thus, in a short time, be in a condition
suitable for the converting process; when worn out the whole mass, shown
in Figure 8, can be removed. The conical ring K, shewn in section at Figure 7,
and bolted to the lower part of the vessel, will determine the line of separa-
tion of the materials when the tuyere box is removed.
I desire it to be understood that I do not, in these in part recited Letters
Patent, claim the removal of the whole bottom of the vessel with the tuyeres
therein, as the same has already been practised.
The tuyeres used in the manner herein-before described sometimes break
transversely, and the air getting into the crack forces the upper end of the
tuyere into the metal and causes the lower part of the tuyere to quickly wear
away. To prevent this I make a somewhat larger hole in the centre of the
tuyere, roughened or corrugated throughout its length; into this I insert an
iron bolt or rod, also roughened or formed with rings on its surface; I pour
some cement into the space formed between it and the inside of the tuyere
hole, so that the tuyere may be effectually held in place even if a fracture
should take place. A longitudinal section of a tuyere so constructed is shown
at Figure 9 on the Sheet of Drawings annexed, where N, N, show the air
passages, and P the corrugated or ribbed iron rod or bolt put into the cor-
rugated central opening and then run in with a mixture of Portland cement
and ground fire-brick, or with other suitable cement.
In the manufacture of malleable iron and steel from crude iron, or from
refined or partially refined iron, by forcing atmospheric air into and below the
surface of the fluid metal the air has hitherto been simply conveyed from the
blast engine or air vessel, in a cold or in a heated state, direct into the con-
verting vessel without otherwise altering the properties or gaseous constituents

page_text: of the air so employed, excepting in those cases where steam has been mixed
therewith; but I have found that the molten iron and the substances incor-
porated therewith may be acted upon more or less advantageouslybycharging
or impregnating the air with the vapours of acids, alkaline or saline fluids, or
hydrocarbons, or by passing the air through or between any solid substances
capable of vaporizing or in part vaporizing or altering the properties of the
air with a view to act upon or combine with the substances present in the
crude metal, and thus further refine, purify, or improve its quality. The air
and the fluid or solid substances among which it is passed being either in a
cold or in a heated state, as may be found preferable. In carrying this system
into practical operation I prefer to line the lower part of the air receiver,
which is in communication with the blast engine, with lead or with pottery-
ware, or with other substances not easily destroyed by thefluids to beemployed
therein, the air from the blast engine being conveyed through perforations
situated below the surface of such fluid and being allowed to bubble up
through it, and thus become more or less altered in its properties and chemical
constituents prior to its passage through the tuyeres into the molten metal.
I desire it to be understood that I do not claim as my Invention the employ-
ment of any special fluid matters through which the air is to be passed or
to become impregnated with, as the same will depend on the nature of the
substances contained in the iron which it is intended to act upon, or whether
such alteration of the constituents of the air is effected for the purpose of
increasing the temperature of the contents of the converting vessel, or for
so combining with the oxygen contained therein as better to adapt the air
for use as a means of mixing or agitating the fluid metal after conversion
or otherwise.
Having described the several parts of my said Invention, and the manner
in which the same may be carried into practical operation, I desire it to be
understood that I do not confine myself to the precise details herein given
provided the essential parts of my said improvements be retained, but
what I claim in the manufacture of malleable iron and steel, and in the
apparatus employed in such manufacture, is,-
Firstly, I claim, in the manufacture of malleable iron and steel (when
effected by forcing atmospheric air or other gaseous matters into molten iron)
the employment in the converting vessel of a portion of the charge of pig or
refined iron in a solid and unmelted state, when used at the commencement of
the converting process, in combination with another portion of crude iron in
a fluid state, in the manner and for the purposes herein-before described.
Secondly, I claim the manufacture of cast steel and cast malleable iron

page_text: by mixing and combining molten carburet of iron with other iron or steel in
an unfused state, such unfused iron or steel having been refined, or partially
refined, by puddling, but which has not been manufactured into finished iron,
when the fusion of such refined or partially refined iron or steel is effected
by forcing atmospheric air or other gaseous matters into the molten carburet
of iron mixed therewith.
Thirdly, I claim, when heating the converting vessel, heating or melting
of pig or other iron therein (prior to the conversion thereof), such heating
or melting being effected by a blast of air acting on the fuel contained in
such converting vessel.
Fourthly, I claim the heating or melting of pig or other iron in the con-
verting vessel (prior to the conversion thereof), such heatingor melting being
effected by jets of carbonic oxide, carburetted hydrogen, or other gases and
jets of air forced through the tuyeres into the converting vessel.
Fifthly, I claim the use of a perforated plate covered by a suitable woven
fabric, and the employment of a partial vacuum for drying or consolidating
the materials employed in setting tuyeres in converting vessels.
Sixthly, I claim the mode herein described of securing the tuyeres to the
tuyere box, and the removal or replacing them in a dried state without taking
off the bottom of the converting vessel, as described.
Seventhly, I claim the mode herein described of strengthening a tuyere
by a central iron rod and thus holding the parts thereof together when
fractured.
Eighthly, I claim, in the manufacture of malleable iron and steel, passing
the atmospheric air to be employed in its conversion through and in contact
with acids or alkaline solutions or hydrocarbons, prior to the passage of
the air through the tuyeres into the converting vessel.
In witness whereof, I, the said Henry Bessemer, have hereunto set my
hand and seal, this Fifth day of May, in the year of our Lord One
thousand eight hundred and sixty-four.
HENRY BESSEMER. (L.S.)