IMPROVEMENTS IN THE MANUFACTURE OF CAST AND WROUGHT IRON AND STEEL, AND IN THE FURNACES EMPLOYED THEREFOR
Year: 1868

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn
Fields, in the County of Middlesex, Gentleman, for the Invention
of "IMPROVEMENTS IN THE MANUFACTURE OF CAST AND WROUGHT IRON
AND STEEL, AND IN THE FURNACES EMPLOYED THEREFOR."-A communi-
cation from abroad by Auguste Ponsard and François Eugène
Boyenval, of Paris, in the Empire of France.
Sealed the 19th January 1869, and dated the 24th July 1868.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition,
on the 24th July 1868.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF CAST AND WROUGHT
IRON AND STEEL, AND IN THE FURNACES EMPLOYED THEREFOR," a communica
tion to me from abroad by Auguste Ponsard and François Eugène
Boyenval, of Paris, in the Empire of France, to be as follows:-
This Invention relates to a peculiar process and furnace for manu-
facturing cast and wrought iron and steel whereby the costly blast
furnaces hitherto employed are entirely dispensed with.

page_text: The peculiar furnace employed in carrying out this Invention is
constructed somewhat similar to a reverberatory furnace with a double
sloping hearth for the collection of the molten metal. The hearth is heated
either by an ordinary fire-place or furnace, or by gas, in which latter
case a Siemens' or other like apparatus well know to metallurgists would
be employed, the flame and products of combustion entering by suitable
conduits at one end of the furnace and passing off by other like conduits
situate at the opposite end. Upon each of the sloping sides of the
hearth rest the lower ends of a number of vertical fire-clay tubes or
crucibles without bottoms, such tubes entering at their upper ends with
holes in the roof of the furnace, which roof is covered by a cast-iron
plate forming a platform and being provided with moveable lids which
fit over the mouths of the different springs leading down into the tubes.
The ore, fluxes, and fuel are suitably fed into the several tubes from
the platform or plate above referred to, and heat is then applied to the
furnace, the flames circulating or playing round the exteriors of the
several charged tubes and effecting the fusion of the ore without coming
into actual contact therewith, and may be of any quality, whilst the
small amount of fuel contained inside the tubes along with the ore and
flux in order to effect the deoxidation of the ore and the carburation of
the metal should be of the best quality. It will thus be seen that two
distinct kinds of fuel are employed, namely, the ordinary fuel for the
purposes of fusion and a superior fuel of which only a small proportion
is required inside the tubes or bottomless crucibles, hence a considerable
economy is obtained over the ordinary system of blast furnace. The
molten cast iron runs out of the bottoms of the vertical tubes and down
the sloping sides of the hearth, and as fast as the contents of the tubes
subsides or descends fresh supplys of ore, fuel, and flux are added, thus
rendering the process continuous. The molten metal is run off through
a tapping hole in the side of the furnace, and the slag is removed through
a separate opening from time to time as required.
In making cast iron the ore previously roasted and broken up into
small fragments is thrown into the vertical tubes, and the requisite
quantity of flux added alternately. each charge of ore with a charge of
small coal or coke or wood, charcoal. The covers are placed over the
tubes and the furnace started, when the molten cast iron will be obtained
as above described, and may be cast into pigs or run direct into the
foundry ladle.

page_text: In making wrought iron the same apparatus is employed, and the
wrought iron is obtained direct from the ore. The ore employed should
be first reduced to a metallic state by subjecting it to an elevated
temperature in a furnace in contact with the fuel. The ore thus reduced
is introduced into the vertical fire-clay tubes, and the process continued
as for the production of cast-iron, taking care however that no coal be
mixed with the ore, which would in such case become carburated, the
result being cast iron or steel.
In making steel the process is the same as for cast and wrought iron,
the tubes being charged with ore reduced to a metallic state and mixed
with a suitable proportion of crushed fragments of cast iron.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 22nd January 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of July, in the year
of our Lord One thousand eight hundred and sixty-eight, in the 32nd
year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Henry Johnson, Her special
license that I, the said John Henry Johnson, my executors, ad-
ministrators, and assigns, or such others as I, the said John Henry
Johnson, my executors, administrators, or 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 Inven-
tion for "IMPROVEMENTS IN THE MANUFACTURE OF CAST AND WROUGHT IRON
AND STEEL, AND IN THE FURNACES EMPLOYED THEREFOR," a communication
from abroad by Auguste Ponsard and Francois Eugene Boyenval, of
Paris, in the Empire of France, upon the condition (amongst others)
that I, the said John Henry Johnson, my executors or administrators,
by an instrument in writing under my hand and seal, should particularly

page_text: 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 John Henry Johnson, 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, reference being had to the accom-
panying Drawings, and to the letters and figures marked thereon, that
is to say:-
The said Invention relates to a peculiar process and furnace for
manufacturing cast and wrought iron and steel whereby the costly blast
furnaces employed are entirely dispensed with.
The peculiar furnace employed in carrying out this Invention is con-
structed somewhat similar to a reverberatory furnace, with a double
sloping hearth for the collection of the molten metal. The hearth is
heated either by an ordinary fire-place, or furnace, or by gas, in which
later case a Siemens' or other like apparatus well known to metallurgists
would be employed, the flame and products of combustion entering by
suitable conduits at one end of the furnace and passing off by other like
conduits situate at the opposite end. Upon each of the sloping sides
of the hearth rest the lower ends of a number of vertical fire-clay tubes
or crucibles without bottoms, such tubes entering at their upper ends
into holes in the roof of the furnace, which roof is covered by a cast-
iron plate forming a platform, and being provided with moveable lids
which fit over the mouths of the different openings leading down into
the tubes. The ore, fluxes, and fuel are suitably fed into the several
tubes from the platform or plate above referred to, and heat is then
applied to the furnace, the flames circulating or playing round the
exteriors of the several charged tubes, and effecting the fusion of the ore
without coming into actual contact therewith. The fuel employed in
the furnace may be of any quality, but the small amount of fuel
contained inside the tubes along with the ore and flux for the purpose of
effecting the deoxidation of the ore and the carburation of the metal
should be of the best quality only. It will thus be seen that two distinct
kinds of fuel are employed, namely, the ordinary fuel for the purposes
of fusion, and a superior fuel of which only a small proportion is
required inside the tubes or bottomless crucibles, hence a considerable

page_text: economy is obtained over the ordinary system of blast furnace. The
molten cast iron runs out of the bottoms of the vertical tubes and down
the sloping sides of the hearth, and as fast as the contents of the tubes
subsides or descends fresh supplies of ore, fuel, and flux are added, thus
rendering the process continuous. The molten metal is run off through
a tapping hole in the side of the furnace, and the slag is removed
through a separate opening from time to time as required.
In making cast iron the ore previously roasted and broken up into
small fragments is thrown into the vertical tubes and the requisite
quantity of flux added, alternating each charge of ore with a charge of
small coal, or coke, or wood charcoal. The covers are placed over the
tubes and the furnace started, when the molten cast iron will be obtained
as above described, and may be cast into pigs or run direct into the
foundry ladle.
In making wrought iron the same apparatus is employed, and the
wrought iron is obtained direct from the ore. The ore employed should
be first reduced to a metallic state by subjecting it to an elevated
temperature in a furnace in contact with the fuel. The ore thus reduced
is introduced into the vertical fire-clay tubes and the process continued
as for the production of cast iron, taking care, however that no coal be
mixed with the ore, which would in such case become carburetted, the
result being cast iron or steel.
In making steel the process is the same as for cast and wrought iron,
the tubes being charged with ore reduced to a metallic state and mixed
with a suitable proportion of crushed fragments of cast iron.
And in order that the said Invention may be fully understood I shall
now proceed more particularly to describe the same, and for that purpose
shall refer to the several Figures on the Sheet of Drawings hereunto
annexed, the same letters of reference indicating corresponding parts in
all the Figures.
Figure 1 of the annexed Sheet of Drawings is a longitudinal vertical
section (taken along the line A, B, (Figures 2 and 3,) Figure 2 a
horizontal section taken along the line E, F, (Figures 1 and 3, and
Figure 3 a transverse section taken along the line C, D, (Figure 1)
of the improved furnace or apparatus herein-before referred to.
A is a furnace somewhat similar to a reverberatory furnace in which
are placed tubes B of refractory clay herein-after called crucible tubes.
These tubes are disposed vertically in the interior of the furnace, their

page_text: upper ends entering the roof, whilst their lower extremities rest on the
inclined hearth of the furnace in such a manner however as to admit
of the molten metal flowing freely over the hearth into the central
basin C, where it collects, and whence it is withdrawn through the tap
holes D formed in the sides of the furnace. The appertures E placed
above the tap holes are provided for the purpose of removing the slag
and cleaning off the dirt. The crucible tubes B which enter the roof
of the furnace are continued to a certain height by brickwork F of
refractory bricks or fire-clay, at the level of which there is laid down
a flooring G of cast iron for the workmen employed to charge the
crucible tubes B, the appertures of the prolonged portions of such tubes
being situate on the flooring G. These apertures are provided with
lids or covers which serve to cover them after each successive charge.
The furnace herein-before described and represented on the Drawing is
supposed to be heated by gas by means of a special apparatus, such as
that of Siemens' or of any other system. The gas and air are introduced
at the extremities of the furnace through the flues H, and the products of
combustion escape through the appertures I after circulating or playing
round the crucible tubes, which the ignited current of air and gas is in-
tended to raise to an elevated temperature in order to produce fusion of
the ore contained in such tubes. These crucible tubes may be of a round,
rectangular, or elliptic section, and any required number may be used, and
they may be of any suitable dimensions; they are, in fact, crucibles
without bottoms, so that crucibles placed in the same conditions and with
the bottom perforated with one or more holes in order to allow the melted
metal to run out would give precisely the same results, and the tubes
are only preferred on account of their being less costly. This furnace
may be heated by a fire direct like the majority of reverberatory and
puddling furnaces.
I shall now proceed to describe the mode of operation for the manu-
facture of cast iron, wrought iron, and steel.
Manufacture of Cast Iron.-In order to manufacture cast iron, iron ore
previously calcined and suitably crushed is introduced into the crucible
tubes B, and the requisite quantity of flux is added, consisting of either
lime, clay, or silica, according to circumstances, each charge of ore being
alternated by a charge of small coal or coke, or what is better of charcoal.
The quantity of fuel should be increased in proportion to the required
degree of carburation of the cast iron. The tubes having thus been filled

page_text: to the level of the flooring G, the covers are placed on the top and the
operator may then commence to heat the furnace. In lieu of charging
the crucible tubes with alternate layers of ore, flux, and fuel, these
three materials may be previously mixed and supplied in that state to
the crucible tubes. As the fusion proceeds and the charges sink in the
crucible tubes the supplies are renewed, and the operation may thus be
carried on in a continuous manner. When the slag has accumulated
in the central basin C, which receives all the molten metal from the
whole of the crucible tubes B, it is tapped off through the apertures E,
care being taken to leave a sufficient quantity to preserve the cast iron
from oxidizing currents. When a sufficient quantity of cast iron has
been collected in the basin C it is tapped off through the hole D formed
in the gutter. The cast iron is either run direct into pigs, as in blast
furnaces, or received into ladles to be run into moulds.
Manufacture of Wrought Iron.-For the manufacture of malleable iron
direct from the ore the same apparatus is employed. The ore employed
should be reduced to a metallic state, which is effected in a retort furnace
by maintaining the ore to be reduced in contact with suitable fuel and
submitting it to an elevated temperature. The ore having been thus
reduced the operation is conducted as for the manufacture of cast iron
by charging the crucible tubes with this ore mixed with the fluxes
necessary for the fusion of the gangue. Great care should be taken to
prevent any of the fuel from remaining with the ore, which in that case
would be carburetted and produce either cast iron or steel, according to
the quantity of fuel remaining mixed with it. The operation is con-
tinued the same as for cast iron by charging the crucible tubes in
proportion to the progress of the fusion and when a sufficient quantity.
of the molten metal has accumulated in the central basin C it is run
into cast iron ingot moulds or otherwise tapped off.
Manufacture of Steel.-For the manufacture of steel the process is
conducted the same as for cast iron and wrought iron by employing the
same apparatus. The crucible tubes B are charged with the iron ore
reduced to a metallic state and mixed with cast-iron fragments in such
proportions as is considered necessary for the due carburation required
for the particular quality of steel to be produced. The tapping-off is
effected in the manner herein-before described for cast and wrought
iron.
In producing iron and steel the ore may also, if desired, be treated
directly without being previously reduced as herein-before described,

page_text: the reduction being effected in the crucible tubes; in this case iron
and steel will only be obtained by the-admixture with the ore in the
crucible tubes of a suitable quantity of carburetting material or
fuel.
In producing wrought iron such a quantity only of coal or charcoal is
employed as is sufficient for the reduction of the ore, but for steel
rather more coal or charcoal must be used than is required for wrought
iron in order to effect the required carburation.
The form of apparatus or furnaces employed in carrying out the
processes herein-before described may be varied from that indicated in
the Drawing, and may contain a greater or less number of crucible tubes
which may be heated either direct with any ordinary or other fuel
or by means of gas produced in special apparatus.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used
or carried into effect, I would observe in conclusion that what I
consider to be novel and original, and therefore claim as the Inven-
tion secured to me by the herein-before in part recited Letters
Patent is,―
First. The production of cast iron, malleable iron, and steel by a
continuous process in crucibles of a tubular form open at both
extremities, or in crucibles perforated at the lower portion, substantially
as herein-before described.
Second. The construction and arrangement of apparatus for producing
cast iron, malleable iron, and steel, substantially as herein-before described
and illustrated by the annexed Sheet of Drawings.
In witness whereof, I, the said John Henry Johnson, have to
this my Specification set my hand and seal, this Twenty-second
day of January, One thousand eight hundred and sixty-nine.
T HENRY JOHNSON
J HENRY JOHNSON
(L.C.)