IMPROVEMENTS IN THE MANUFACTURE OF IRON
Year: 1856

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 IRON."
Sealed the 10th February 1857, and dated the 18th November 1856.
PROVISIONAL SPECIFICATION left by the said Henry Bessemer at the
Office of the Commissioners of Patents, with his Petition, on the 18th
November 1856.
I, HENRY BESSEMER, of Queen Street Place, New Cannon Street, in the
City of London, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF IRON," to be as follows:-
This Invention relates to certain modes of constructing and employing
reverberatory or puddling furnaces in the manufacture of iron, whereby I am
enabled to facilitate the process of puddling, and to employ the spare heat of
the puddling furnace in the process of remelting, and in the process of refining
other portions of iron, and also for the reduction of the slags or oxides of iron
and the obtainment of metallic iron therefrom.
In carrying my Invention into practical operation I construct a puddling
furnace with its fire-grate and puddling hearth of the usual form, or nearly so.
At that end of the hearth farthest from the fire-grate I make a second hearth
or chamber, by preference of smaller area, but deeper than the first-named one
and at a higher level. Beyond this second hearth or chamber I construct a

page_text: third one, at a lower level than the first or puddling hearth, and I give to the
roof of the furnace such a form as will best deflect the heated products of
combustion on to the materials occupying the three hearths. At one end of
the furnace I construct a chimney, which I prefer to make somewhat higher
than those generally used for puddling furnaces, so as to insure a powerful
draught. The reverberatory furnace having been thus arranged may be
employed according to either of the following modes :-
Firstly, pig iron, refiners' plate metal, or other refined iron is put into the
hearth No. 2. while another charge is being puddled in the hearth No. 1. As
soon as the latter is made into puddle balls and is removed from the furnace
the metal melted in the hearth No. 2 is to be let down by removing a sand or
clay plug, and may then be replaced by another charge of pigs or plate metab
which will in turn be melted while the puddling of the charge last let down
into the lower hearth is being proceeded with.
In the second modified process pig iron is put into the hearth or chainber
No. 2, and when melted is blown by tuyeres, in the same manner as that
usually practised in the finery furnace, whereby the metal will pass from the
condition of pig irou to that of finers' plate metal, and in that state may be let
down while yet fluid into the hearth No. 1 to be there puddled while another
charge of pig iron is undergoing the remelting and refining process. Water
boxes and tuyeres as usually employed in finery furnaces may be used, but I
prefer to use fire-brick to form the finery hearth.
In the third modified process the pig iron is to be melted in the hearth
No. 2, as lastly described, and the hearth is to be provided with tuyeres
situated below the level of the metal, so that air or steam, or a mixture of
air and steam alone or mixed also with any substance containing or capable
of evolving oxygen, or with a mixture of salt, oxide of manganes, lime, or
other substances that have been heretofore employed in the refinement of
iron, is to be blown or forced into and below the surface of the molten
iron until it is thereby highly refined, when it may be let down into the
lower hearth and be quickly puddled and formed into balls.
When treating iron according to either of the processes herein-before
described, slag containing oxide of iron will be formed both in the puddling
hearth No. 1 and in the melting or refining hearth No. 2, from which a
channel or gutter will convey it when desired into the hearth No. 3; this
quantity of slag will in some cases be increased by the addition of mill scales,
red iron ore, or other oxides of iron used to facilitate the puddling process; or
the mill scales or other slags or oxides produced in the manufacture of iron
may be put direct into the hearth No. 3, where the heat and flame that has

page_text: prassed over the other hearths of the furnace will act upon them and assist in >
their reduction. Coke, coal, bituminous shale, coal tar, or other carbonaceous
matters are to be added to or forced into the fluid-slag or cinder, and be well.
incorporated with it by stirring or otherwise, until it is judged that the process
of reduction is complete, when the fluid scoria that still remains may be run,
off, by, a suitable tapping hole, and the molten.iron-obtained therefrom.be also.
run off at a lower level and be afterwards refined and puddled or be used..for
other purposes.
In the reduction of the slag, lime, clay, sand, salt; oxide of manganese, or
blast furnace slag may be used to flux the materials and assist in taking up
the impurities as the nature of the slags may render expedient; carbonaceous-
gases may also be forced into the fluid cinder in addition, to or in lieu of the
use of the solid carbonaceous matters, as before described.
In such cases as it may be preferred to remelt or refine the metal in. a.
separate furnace to that in which the iron is puddled, I dispense with the use
of the melting or refining hearth No. 2, and only employ the usual puddling
hearth combined with a hearth for reducing slags and oxides of iron; and here
I would remark that in the arrangement of reverberatory furnace with two or
three hearths for the purposes herein described, it will be obvious that the
relative position of the hearths and the size of them, may be considerably.
varied without departing from the principle of my Invention:
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed.
by the said Henry Bessemer in the Great Seal Patent Office on the
18th May 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BESSEMER, of Queen Street Place, New Cannon Street, in the City of London,
send gecting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of November, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth 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
terp therein expressed, should and lawfully might make, use, exercise, and

page_text: 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 IRON," 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 sune 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 :-
-
This Invention relates to certain modes of caustructing and employing
reverberatory or puddling furnaces in the manufacture of iron, whereby I am
enabled to facilitate the process of puddling, and to employ the spare heat of
the puddling furnace in the process of remelting and in the process of refining
other portions of iron, and also for the reduction of the slags or oxides of iron,
and the obtainment of metallic iron therefrom. In carrying my Invention into
practical operation I construct a puddling furnace with its fire-grate and
puddling hearth of the usual form, or nearly so. At that end of the hearth
farthest from the fire-grate 1 make a second hearth or chamber, by prefer-
ence of smaller area, but deeper than the first-named one, and at a higher
level. Beyond this second hearth or chamber I construct a third one at a
lower level than the first or puddling hearth, and I give to the roof of the
furnace such a form as will best deflect the heated products of combustion
on to the materials occupying the three hearths. At one end of the flunaeo
I construct a chimney, which I prefer to make somewhat higher than those
generally used for puddling furnaces, so as to insure a powerful draught.
And in order that the construction and arrangements of the several parts
which constitute my improved furnace may be readily understood, I have
represented the same on the Sheet of Drawings hereunto annexed, whero
Figure 1 is a longitudinal vertical section through the centre of the furnace;
Figure 2, a horizontal section on the line A, B, of Figure 1; and Figure 3 is
a vertical cross section of the same, taken on the line C, D, of Figure 2.
a is the fire-place, supplied with fuel through the opening à; and c is the fire
bridge, which separates the fire-place from the puddling hearth No. 1. These
parts of the furnace may be constructed in the usual manner both as regards
tlicir general configuration and the materials used in their construction, and in

page_text: like manner may be provided with a sliding door e, having an opening e*
through which the workman operates upon the charge of metal, as in the ordi-
nary process of puddling iron. No. 2 represents the second hearth, used for,
remelting and refining the metal; and No. 3 is the third hearth, in which the
fluid cinder is reduced to the metallic state. f is a door for the purpose of
introducing the metal into the furnace; and g, g, are fire-clay or other suitable
tuyere pipes, for the purpose of introducing a blast of air, steam, or other
matters into and below the surface of the molten iron in the hearth No. 2; an.
opening is also made at the lowest part thereof for the purpose of discharging;
the fluid matters therefrom into the gutter i; this gutter is made to com-.
municate by means of the opening m with the hearth No. 1, and also with the
hearth No. 3 by means of the opening n; cach of the openings h, m, and n
being closed, when desired, by a stopping of sand or loam, as practised in stop-
ping the tapping holes of the cupola furnaces in common use for founding iron.
The hearth No. 3 is also provided with a sliding door p, having a hole therein
for the purpose of allowing the workman to stir up and operate upon the
cinder, as required; at the lowest part of this hearth there is formed the dis-
obarge holo q, secured with a stopping of loam, and used for running out tho
reduced metal and other matters by the spout r. The chimneys I prefer to
make about twenty feet higher than those generally employed in puddling.
furnaces, in order to compensate for any dimunition of draught which may be.
caused by the absorption of a portion of the heat in passing through the hearths
Nos. 2 and 3. The chimney may be made to rest on the end of the furnace,
as represented in the Drawings, or it may form an independent structure sup-.
ported on an iron frame, as already practised; or, whon preferred, the flue may,
be carried downward and connected with an underground flue leading to a.
large chimney shaft of sufficient height to insure a powerful draught. The
reverberatory furnace having been thus arranged may be employed according
to either of the following modes.:―
Firstly, pig iron, refiners' plate metal, or other refined iron is put into the.
hearth No. 2, while another charge is being puddled in the hearth No. 1. As
soon as the latter is made into puddled balls and is removed from the furnace,
the metal melted in the hearth No. 2 is to be let down by removing a sand or
clay plug , and may then be replaced by another charge of pig or plate metal,
which will in turn he melted while the puddling of the charge last let down
into the lower hearth is being proceeded with.
In the second modified process, pig iron is put into the hearth or chamber
No. 2, and when melted is blown by tuyeres, in the same manner as that
usually practised in the finery furnace, whereby the metal will pass from the

page_text: condition of pig iron to that of finers' plate metal, and in that state may be let
down while yet fluid into the hearth No. 1, to be there puddled, while another
charge of pig iron is undergoing the remelting and refining process. Water
boxes and tuyers, as usually employed in finery furunces, may be used, but I
prefer to use firo-brick to form the finery hearth.
In the third modified process, the pig iron is to be melted in the hearth
No. 2, as lastly described, and the hearth is to be provided with tuyers. 9, 9,
situated below the level of the metal, so that air or steam, or a mixture of air
and steam alone, or mixed also with any substance containing or capable of
evolving oxygen, or with a mixture of salt, oxide of manganese, lime, or other
substances that have heretofore been employed in the refinement of iron, are to
be blown or forced into and below the surface of the molten iron until it is.
thereby highly refined, when it may be let down into the lower hearth and be
quickly puddled and formed into balls.
When treating iron according to either of the processes herein-before
described, slag containing oxide of iron will be formed both in the puddling
hearth No. 1 and in the melting or refining hearth No. 2, from which a
channel or gutter i will convey it when desired into the hearth No. 3; this
quantity of slag will in some cases be increased by the addition of mill
scales, red iron ore, or other oxides of iron used to facilitate the puddling
process; or the mill scales or other slags or oxides produced in the manu-
facture of iron may be put direct into the hearth No. 3, where the heat and
flame that has passed over the other hearth of the furnace will act upon them
and assist in their reduction. Coke, coal, bituminous shale, coal tar, or
other carbonaceous matters are to be added to or forced into the fluid slag
or cinder, and be well incorporated with it by stirring or otherwise until
it is judged that the process of reduction is complete, when the fluid scoria
that still remains may be run off by a suitable tapping hole q, and the
molten iron obtained therefrom be also run off at a lower level, and be
afterwards refined and puddled, or be used for other purposes.
In the reduction of the slag, lime, clay, sand, salt, oxide of manganese or
blast furnace slag may be used to flux the materials and assist in taking up
the impuritics as the nature of the slags may render expedient; carbonaceous
gases may also be forced into the fluid cinder in addition to or in lieu of the
use of the solid carbonaceous matters, as before described. In such cases, as
it may be preferred to remelt or refine the metal in a separate furnace to that
in which the iron is puddled, I dispense with the use of the melting or refining
hearth No. 2, and only employ the usual puddling hearth, combined with a
hearth for reducing slags and oxides of iron.

page_text: And here I would remark that in the arrangement of a reverberatory fur-
nace with two or three hearths, for the purposes herein described, it will be
obvious that the relative position of the hearths and the size of them may be
considerably varied without departing from the principle of my Invention, and
the details herein specified for carrying into effect my Invention may be varied,
provided the peculiar character thereof be retained.
In witness whereof, I, the said Henry Bessemer, have hereunto set my
hand and seal, this Eighteenth day of May, in the year of our Lord
One thousand eight hundred and fifty-seven.
Witness,
S. CARPMAEL.
HENRY BESSEMER. (L.S.)