IMPROVEMENTS IN THE MANUFACTURE OF STEEL, AND IN THE MANUFACTURE AND TREATMENT OF CAST METALS, AND IN THE APPARATUS EMPLOYED THEREIN
Year: 1876

page_text: Filed 14th March 1877.
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 Royal Letters
Patent bearing date the 10th day of March One thousand eight hundred and
seventy-six, and numbered 1047, did for Herself, Her heirs, and successors, give
and grant unto me, the said John Henry Johnson, my executors, administrators,
and assigns, Her special license, full power, sole privilege and authority, that I,
the said John Henry Johnson, my executors, administrators, 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 Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF STEEL, AND IN THE MANUFACTURE AND TREATMENT OF CAST
METALS, AND IN THE APPARATUS EMPLOYED THEREIN," a communication to me from
abroad by Auguste Ponsard, of Paris, in the Republic of France, upon the condition
(amongst others) that I, the said John Henry Johnson, by an instrument in writing
under my hand and seal, 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 iminediately after the date of the said Letters Patent :
And whereas, I, the said John Henry Johnson, by an instrument in writing
under my hand and scál, did declare the nature of the said Invention and in what
manner the same was to be performed, and caused the same to be filed in the Great
Seal Patent Office on the Ninth day of September, One thousand eight hundred
and seventy-six :
And whereas I have ascertained that the subject matter of the second and third
claims of the said Specification is of doubtful novelty, and that parts of the
apparatus which forms the subject matter of the first claim had previously to the
date of the said Letters Patent been used in a modified form, and that such parts

page_text: are moreover of doubtful utility, and I am therefore desirous of striking out the
second and third claiming clauses and such portions of the Specification as relate
to the said parts of the apparatus, and altering the first claiming clause for the
purpose of limiting the claim to such parts of the apparatus as are new and useful
in the manner herein-after more fully appearing:
NOW KNOW YE, that I, the said John Henry Johnson, by and with the leavo
of Her Majesty's Attorney-General, and for reasons aforesaid, do disclaim and alter
parts of the description and claims of the present Invention as contained in the
suid Complete Specification in manner following:-
**
I insert between the word "of" and the word "a" which occur in line 31, of
page 3 of the Queen's Printer's copy of the said Specification, published in One
thousand eight hundred and seventy-six, the words "a peculiar construction and
arrangement of converter or apparatus enabling;" I also insert between the words
"manufacture" and "combining," which occur in the same line 31 of page 3 of the
said Queen's Printer's copy, the words "to be employed;" I also strike out the
words "In carrying out this Invention and arrangement of" which occur at line 34
of the same page 3, and substitute therefor the word "This ;" I also strike out the
words "is adopted consisting" which occur in the same line 34 of the same page 3,
and substitute therefor the word "consists;" I also strike out the words commencing
"The Sheet of Drawings" and the following words down to and including the
words "in a liquid condition," which occur in lines 40 to 50 of the same page 3, of
the said Queen's Printer's copy; I also strike out the words "oscillating or rolling"
which occur in lines 9 and 10 of page 4, of the said Queen's Printer's copy, and
substitute therefor the word "inclined;" I also strike out the words commencing
Figures 4, 5, 6, and 7, shew," and of the following words down to and including
the words "shewn in Figures 1, 2, and 3," which occur on lines 40 to 57 of page 4,
and lines 1 to 12 of page 5, of the said Queen's Printer's copy; I also strike out
the word "First" which occurs on line 56 of the same page 5; I also strike out the
words "as herein-before described," which occur on line 57 of the same page 5, and
substitute therefor the words " consisting of the combination with a furnace of a
"removable sole or hearth mounted upon an inclined hollow axis, and provided
"with tuyeres so arranged that a blast may be introduced through the hollow axis,
"and the tuyeres into the molten metal, and that the surface of the molten metal
may be brought below such tuyeres by partially rotating the sole or hearth,
substantially as herein-before described;" I also strike out the words commencing
Second. The system," and the following words down to and including the words
in the manner herein-before described," which occur on lines 1 to 7 of page 6 of the
said Queen's Printer's copy.
"
"
«
ss
"
And in order that the effect of the said Disclaimer and Memorandum of Altera-
tion may be better understood, I annex hereto a copy of the said Specification as it
will appear when so altered and amended, the Provisional Specification and the
preamble and testing clause of the Complete Specification being omitted.
The said Invention relates to improvements in the manufacture of steel and other
metals capable of being cast, and consists more especially in the employment of a
peculiar construction and arrangement of converter or apparatus enabling a mixed
system of manufacture to be employed combining the advantages resulting in the
Danufacture of steel by the method known as Bessemer's process, and by and from
the method by reaction.
This apparatus consists of a furnace having a moveable sole or hearth, which is
provided with a series of tuyeres arranged in such a manner as that a blast of
compressed air can be made to pass into and through the fluid metal during the
conversion or the treatment of the fused metal, and so arranged as that the buyeres
may be placed above the bath as soon as the blast in the apparatus is stopped.
The process of manufacture employed according to this Invention is a mixed
process, as previously stated. The melted cast iron placed in a furnace with a move-
able sole is first submitted to a strong current of air, as in the Bessemer process;
then the fluid kept hot in the furnace is treated as in the process by reaction, that

page_text: is to say, the metal is tested and modified by the addition of carburetting or
oxidizing substances as required, and run off when the desired quality is obtained.
The description of furnace employed may consist of a gas furnace or any other
furnace capable of obtaining and sustaining a high temperature, such for example
as a furnace constructed on the systems known as Ponsard's, Siemen's, or
Crampton's, a furnace for burning heavy oils, or a direct acting furnace, with or
without a blast; but in all cases it is provided with a moveable sole or heartlı,
pivotting, inclined, and arranged in such a manner that the molten metal may be
displaced sufficiently to uncover the tuyeres serving for the blast as soon as the
blast of air is arrested in the apparatus.
Figures 1, 2, and 3 of the Drawing hereunto annexed illustrate in vertical section
the use of a moveable pivoting sole or hearth (marked A in the Drawings)
arranged in an inclined plane and placed under the roof B of a gas furnace. The
gases enter at one end and escape at the opposite end as indicated by the arrows in
Figure 1.
A current of air supplied by a blowing engine enters by the pivot A¹ of the hearth
which forms a chamber, and the current is thence conducted by a pipe B¹ placed
under the sole or hearth A into the tuyere box C. The tuyeres a, a, are arranged
at one side and the tapping hole D is placed at the opposite side.
By reason of the sole or hearth being inclined all the molten metal becomes accu-
mulated on the side where the tuyeres are situate, as shewn in Figure 3, and
in this position the air passing through the metal refines it as in a Bessemer
converter.
When it is considered that the operation is sufficiently advanced the sole A is
caused to make half a revolution by the aid of the gearing A2 or other suitable
means, and the fluid metal flows over to the side at which the tapping hole D is
placed, as shewn in Figure 2.
The quality of the metal can then be tested through a manhole P (Figure 3) placed
above as in the ordinary manner when steel is manufactured on a sole or hearth,
carburetting or oxidising substances can be added, and at the desired moment spiegel
eisen, ferro-manganese, or other suitable metal may be introduced, and finally the
metal is run off either into a ladle D' as from a Bessemer converter, or into a series
of moulds passing before the tapping hole.
The cast iron may be charged either in a fluid state or in a cold condition and
melted, and when the cast iron is melted a portion of scrap may be fused in it
and the refining completed by the blast, or if desired cast iron may be employed
alone.
The cast iron may, as in the Bessemer process, be taken from the blast furnace,
the blowing engine of which may also be employed for the supply of air or blast by
suitably regulating the height of the fluid metal in the apparatus. The cast iron
may also be placed in the convertor when cold, be melted as in an ordinary rever-
beratory furnace, and afterwards be refined by the blast.
One of the most important features of this system is that it enables all kinds of
cast iron to be treated without distinction, that is to say, that whilst the cast iron
to be employed in the Bessemer apparatus is required to possess certaiu qualities
which are not suitable for the manufacture of steel on a sole or hearth, such cast
iron may be treated in this apparatus, since the refining is to be effected not by the
blast alone, but also by dissolving scrap iron or other suitable substances in the
fluid metal.
Cast iron which is not suitable for treatment by the Bessemer process, such for
example as cast iron deficient in silicon, may also be employed with equal advantage
in this apparatus, such cast iron being heated to the desired point in the furnace
before submitting it to the induced current of air or blast.
It should also be observed that in manufacturing steel by the Bessemer process
it is difficult to pass into the converter all the bar ends and waste pieces which the
manufacture requires, so that the establishment of melting furnaces becomes a
necessary complement to the said process; on the other hand, in the manufacture of

page_text: steel upon a hearth by reaction, cast iron cannot be treated alone, and it becomes
necessary to effect the refining by dissolving a considerable quantity of wrought
iron in the fluid metal, say about 2, or 3/4 of the total weight of the charge, which
involves considerable expense.
By means of this Invention however these two objections are obviated, as it
enables all waste and bar ends, resulting from the conversion of cast iron into steel
or castings, to be dissolved in the fluid metal, and moreover cast iron may be
employed alone.
The facility which this system offers for refining, not only admits of all kinds of
cast iron being employed, whether containing manganese or silicon or not, but even
impure metal, which may be purified by injecting through the tuyere reagents,
which cannot be efficaciously employed in manufacturing upon a hearth. For
example, it is possible to dephosphorate cast metal by producing oxidized scorice in
as large quantities as may be judged desirable, this system of treatment admitting
of substances calculated to recarburize the metal to the degree required, being
introduced into the molten metal, and of the scoriæ formed being discharged by
the tap hole. In like manner iron containing a large proportion of silicon may
by employed by dissolving in it when required a large proportion of scrap iron.
of
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 therefore
claim as the Invention secured to me by the herein-before in part recited Letters
Patent is, the general arrangement and construction of apparatus for the production
of steel and cast metals, consisting of the combination with a furnace of a remove-
able sole or hearth mounted upon an inclined hollow axis and provided with
tuyeres so arranged that a blast may be introduced through the hollow axis and
the tuyeres into the molten metal, and that the surface of the molten metal may be
brought below such tuyeres by partially rotating the sole or hearth, substantially
as herein-before described.
A
In witness whereof, I, the said John Henry Johnson, have hereunto set my
hand and seal, this Nineteenth day of February, in the year of our Lord
One thousand eight hundred and seventy-seven.
I hereby grant my fiat giving leave to the above-named John Henry Johnson 3
to file in the Great Seal Patent Office, with the Specification to which the same
relates, the above-written Disclaimer and Memorandum of Alteration.
JOHN HOLKER,
Temple, March 12th 1877.

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 STEEL, AND IN THE MANUFACTURE AND TREATMENT OF CAST
METALS, AND IN THE APPARATUS EMPLOYED THEREIN." A communication from
abroad by Auguste Ponsard, of Paris, in the Republic of France.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 10th March 1876.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. IMPROVEMENTS IN THE MANUFACTURE OF STEEL, AND IN THE MANU-
FACTURE AND TREATMENT OF CAST METALS, AND IN THE APPARATUS EMPLOYED
THEREIN." A communication from abroad by Auguste Ponsard, of Paris, in the
Republic of France.
This Invention relates to improvements in the manufacture of steel and other
cast metals, and consists particularly in the employment of a mixed system of
manufacture, combining the advantages resulting in the manufacture of steel from
the method known as Bessemer's process, and from the method by reaction.
In carrying out this Invention an arrangement of apparatus is adopted, con-
sisting of a furnace having a movable sole or hearth which is provided with a
series of tuyeres arranged in such a manner that the blast of compressed air is
produced in the fluid metal during the operation, and that these tuyeres become
placed above the bath as soon as the arrival of air in the apparatus is
interrupted.
The apparatus employed may consist of any description of reverberating furnace
of high temperature, with revolving, oscillating, or pivotted sole or hearth, or of
cylindrical or barrel-shaped furnaces, capable of rotating on a horizontal axis.
The process and apparatus are applicable both to the manufacture of steel and to
the puddling of cast iron.
The operation of manufacturing cast steel and iron takes place either in treating
cast iron alone, as in the Bessemer process, or by treating a mixture of cast and
scrap iron as in the manufacture of steel upon a sole or hearth, and the cast iron may
be charged in a cold or in a liquid condition.
[Price 6d.]

page_text: The process of manufacture employed according to this Invention is a mixed
process, as previously stated. The melted cast iron placed in a furnace with a
movable sole is first submitted to a strong current of air, as in Bessemer's process,
then the fluid metal kept hot in the furnace is treated as in the process by reaction,
that is to say, that the metal may be tested and modified by the addition of
carburetting or oxidizing substances as required, and run off when the desired
quality is obtained.
The description of furnace employed may consist of a gas furnace or any
other of high temperature, such, for example, as a furnace constructed on the
systems known as Ponsard's, Siemen's, or Crampton's, a furnace for burning heavy
oils, or a direct acting furnace, with or without a blast, but in all cases it is provided
with a movable sole or hearth, pivotting, oscillating, or rolling, and arranged in
such a manner that the liquid metal may be displaced sufficiently to uncover the
tuyeres serving for the blast as soon as the draught of air is interrupted in the
apparatus.
According to one modification a movable pivotting sole or hearth is arranged in
an inclined plane and placed under the roof of a gas furnace, the carburetting gases
enter at one end and escape at the opposite end.
A current of air supplied by a blowing engine enters by the pivot of the hearth,
which forms a chamber, and the current is thence conducted by a pipe placed under
the sole or hearth into the tuyere box. The tuyeres are arranged at one side, and
the tapping hole is placed at the opposite side. The sole or hearth being inclined
all the fluid metal becomes accumulated on the side where the tuyeres are situate,
and in this position the air passing through the metal refines it as in a Bessemer
converter.
When it is considered that the operation is sufficiently advanced the sole is
caused to make half a revolution and the fluid metal flows over to the side where the
tapping hole is placed.
The quality of the metal can then be tested through a door above, as is dono
when steel is manufactured on a sole or hearth; carburetting or oxidizing substances
can be added, and at the desired moment spiegel eisen, ferro-manganese, or other
metal may be introduced.
Lastly, the metal is run off either into a ladle, as with a Bessemer convertor, or
into a series of moulds passing before the tapping hole.
The cast iron may be charged either in a fluid state or cold, and melted under
the action of the furnace, and when the cast iron is melted a portion of scrap may
be fused in it and the refining completed by the blast, or, if desired, cast iron may
be employed alone.
According to another modification a revolving apparatus is employed, composed
of an iron or other metal cylinder lined with fireclay in the same manner as a
Bessemer retort; it is mounted on a carriage in order that it may be brought
between the two parts of a gas furnace constructed according to what is known as
Ponsard's system. The gas and the carburetting air arrive by conduits at one end,
pass through the hollow of the cylinder, and escape by a passage at the other end
into the regenerator and thence into the chimney.
The cylinder rests at each extremity upon a bearing formed of rollers, so that it
is capable of performing either one revolution or three quarters of a revolution or
merely a small fraction of a revolution on its centre, as required.
The cylinder is placed in position with the tuyeres covered when the fluid metal
is to be submitted to the action of the blast, and then turned into such a position
as to uncover the tuyeres as before-mentioned, and then further partially rotated
in order to enable the metal to be run into a ladle.
The air enters a tuyere box situate at one side and nearly opposite the working
door. The pipe supplying the air is flexible or jointed in such a manner as to be
free to accommodate itself to the various movements of the rotatory cylinder. The
air may be supplied either at one side or at one end of the tuyero box, which is
provided with a movable bottom to admit of the tuyeres being changed as repaired.

page_text: The cast iron may, as in the Bessemer process, be taken from the blast furnace,
the blowing engine of which may even be employed for the supply of air or blast
by suitably regulating the height of the fluid inetal in the apparatus.
The cast iron may also be placed in the converter when cold melted as in an
ordinary reverberatory furnace and afterwards fixed by the blast.
Cast iron may be employed with equal advantage in this apparatus which is not
suitable for treatment by the Bessemer process, such as cast iron deficient in silicon,
the same being superheated in the furnace before submitting it to the forced current
of air.
The facility which is presented by this system for fining not only admits of all
kinds of cast iron being employed, whether containing manganese or silicon or not,
but even impure metal, which may be purified by injecting through the tuyeres
reagents which cannot be efficaciously employed in manufacturing upon a hearth,
thus it is possible to dephosphorate cast metal by producing oxidized scorice in as
large quantities as may be judged advisable, this system of treatment admitting of
carburetting substances calculated to recarburet the metal to the degree required
being introduced into the fluid metal, and of the scorice formed being discharged by
the tap hole.
In like manner very silicious iron may be employed by dissolving in it when
required a large proportion of scrap 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 9th
September 1876.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN THE MANUFACTURE OF STEEL, AND IN THE MANU-
FACTURE AND TREATMENT OF CAST METALS, AND IN THE APPARATUS EMPLOYED
THEREIN." A communication to me from abroad by Auguste Ponsard, of Paris, in
the Republic of France.
The said Invention relates to improvements in the manufacture of steel and
other metals capable of being cast, and consists more especially in the employment
of a mixed system of manufacture, combining the advantages resulting in the
manufacture of steel by the method known as Bessemer's process, and by and from
the method by reaction.
In carrying out this Invention, an arrangement of apparatus is adopted consisting
of a furnace having a moveable sole or hearth, which is provided with a series of
tuyeres, arranged in such a manner as that a blast of compressed air can be made
to pass into and through the fluid metal during the conversion or the treatment
of the fused metal, and so arranged as that the tuyeres may be placed above the
bath as soon as the blast in the apparatus is stopped.
The Sheet of Drawings hereunto annexed illustrates various arrangements of
apparatus whereby this result may be obtained, and which I shall proceed herein-
after particularly to describe, but any description of reverbatory furnace of high
temperature, with revolving, oscillating, or pivotted sole or hearth, or of cylindrical
or barrel shaped furnaces, capable of rotating on a horizontal axis may be employed
in carrying out the Invention.
The operation of producing cast steel and cast iron, according to the methods
usually adopted, is carried out either by treating cast iron alone, as in the process
known as the Bessemer process, or by treating a mixture of cast and scrap iron as
in the manufacture of steel upon a sole or hearth, the cast iron being charged either
in a cold or in a liquid condition.
The process of manufacture employed according to this Invention is a mixed
process as previously stated, the melted cast iron, placed in a furnace with a
inoveable sole, is first submitted to a strong current of air, as in the Bessemer

page_text: process; then the fluid kept hot in the furnace is treated as in the process by
reaction, that is to say, the metal is tested and modified by the addition of
carburetting or oxidizing substances as required, and run off when the desired
quality is obtained.
The description of furnace employed may consist of a gas furnace, or any other
furnace capable of obtaining and sustaining a high temperature, such for example
as a furnace constructed on the systems known as Ponsard's, Siemen's, or Crampton's,
a furnace for burning heavy oils, or a direct acting furnace with or without a blast;
but in all cases it is provided with a moveable sole or hearth, pivotting, oscillating,
or rolling, and arranged in such a manner that the molten metal may be displaced
sufficiently to uncover the tuyeres serving for the blast, as soon as the blast of
air is arrested in the apparatus.
Figures 1, 2, and 3 of the Drawing hereunto annexed illustrate in vertical
section the use of a moveable pivoting sole or hearth (marked A in the Drawings),
arranged in an inclined plane, and placed under the roof B of a gas furnace; the
gases enter at one end and escape at the opposite end, as indicated by the arrows
in Figure 1.
A current of air supplied by a blowing engine enters by the pivot A of the
hearth, which forms a chamber, and the current is thence conducted by a pipe B¹,
placed under the sole or hearth A, into the tuyere box C. The tuyeres a, a, are
arranged at one side, and the tapping hole D is placed at the opposite side.
By reason of the sole or hearth being inclined, all the molten metal becomes
accumulated on the side where the tuyeres are situate, as shewn in Figure 3, and
in this position the air passing through the metal refines it as in a Bessemer
converter.
When it is considered that the operation is sufficiently advanced, the sole A is
caused to make half a revolution by the aid of the gearing A², or other suitable
means, and the fluid metal flows over to the side at which the tapping hole D is
placed, as shewn in Figure 2.
The quality of the metal can then be tested through a manhole P (Figure 3),
placed above as in the ordinary manner; when steel is manufactured on a sole or
hearth, carburetting or oxidising substances can be added, and at the desired
moment spiegel eisen, ferro-manganese, or other suitable metal may be introduced,
and finally the metal is run off either into a ladle D¹ as from a Bessemer converter,
or into a series of moulds passing before the tapping hole.
The cast iron may be charged either in a fluid state or in a cold condition and
melted, and when the cast iron is melted, a portion of scrap may be fused in it,
and the refining completed by the blast, or if desired, cast iron may be employed
alone.
Figures 4, 5, 6, and 7 show a revolving apparatus which may be employed for
the same purpose. It is composed of an iron or other metal cylinder A, lined with
fireclay, and is mounted on a carriage A³ in order to facilitate its introduction
between the two parts B, B2, of a gas furnace constructed according to what is
known as Ponsard's system, as shewn in longitudinal section in Figure 4. The
combustible gases, together with the air, arrive by conduits E, F, at one end, pass
through the interior of the cylinder A, and the products escapo by a passage G at
the other and into the regenerator, and are thence finally discharged into the
chimney. The cylinder A rests at each extremity upon a bearing formed of
rollers b, b, so that it is capable of being made to rotate with facility, and of
performing either one revolution, or three quarters of a revolution, or merely a
small fraction of a revolution on its centre as required.
The transverse sections Figures 5, 6, and 7 represent various positions of the
cylinder. The cylinder is placed in the position shewn in Figure 7, with the
tuyeres a, a, covered when the fluid metal is to be submitted to the action of
the blast, and then turned into the position shewn in Figure 6, so as to uncover
the tuyeres a, a, as before-mentioned, and then further partially rotated in order
to enable the molten metal to be run into a ladle D¹, which latter position is

page_text: indicated in Figure 5. The apparatus is thus capable of assuming the required
positions both for receiving the molten metal and of permitting it to be submitted
to the blast, and of being discharged into a ladle or mould.
The air enters a tuyere box C situate at one side and nearly opposite the
outlet D. The pipe B₁ supplying the air is flexible or jointed so as to be capable
of being employed in conjunction with the rotatory cylinder A. The air may be
supplied either (as shewn in the Drawing) at one side of the tuyere box C, or at
one end thereof; the box is by preference provided with a moveable bottom to
admit of the tuyeres being charged or repaired.
The cast iron is placed in the cylinder either in a liquid or in a solid condition by
the inlet D, and the operation is effected in the manner herein-before described in
the case of the inclined pivoted sole or hearth shewn in Figures 1, 2, and 3.
The cast iron may as in the Bessemer process be taken from the blast furnace,
the blowing engine of which may also be employed for the supply of air or blast
by suitably regulating the height of the fluid metal in the apparatus. The cast
iron may also be placed in the converter when cold, be melted as in an ordinary
reverbatory furnace, and afterwards be refined by the blast.
One of the most important features of this system is that it enables all kinds
of cast iron to be treated without distinction, that is to say, that whilst the cast
iron to be employed in the Bessemer apparatus is required to possess certain
qualities which are not suitable for the manufacture of steel on a sole or hearth,
such cast iron may be treated in this apparatus, since the refining is to be effected
not by the blast alone, but also by dissolving scrap iron or other suitable substances
in the fluid metal.
Cast iron which is not suitable for treatment by the Bessemer process, such for
example as cast iron deficient in silicon, may also be employed with equal advantage
in this apparatus, such cast iron being heated to the desired point in the furnace
before submitting it to the induced current of air or blast.
It should also be observed that in manufacturing steel by the Bessemer process
it is difficult to pass into the converter all the bar ends and waste pieces which
the manufacture requires, so that the establishment of melting furnaces becomes a
necessary complement to the said process; on the other hand, in the manufacture
of steel upon a hearth by reaction, cast iron cannot be treated alone, and it becomes
necessary to effect the refining by dissolving a considerable quantity of wrought
iron in the fluid metal, say about 2/3 or 3/4 of the total weight of the charge which
involves considerable expense.
By means of this Invention, however, these two objections are obviated, as it
enables all waste and bar ends resulting from the conversion of cast iron into
steel or castings to be dissolved in the fluid metal, and moreover cast iron may be
employed alone.
For
The facility which this system offers for refining, not only admits of all kinds
of cast iron being employed whether containing manganese or silicon or not, but
even impure metal which may be purified by injecting through the tuyere reagents
which cannot be efficaciously employed in manufacturing upon a hearth.
example, it is possible to dephosphorate cast metal by producing oxidized scorice
in as large quantities as may be judged desirable; this system of treatment
admitting of substances calculated to recarburize the metal to the degree required
being introduced into the molten metal, and of the scorice formed being discharged
by the tap hole. In like manner iron containing a large proportion of silicon may
be employed by dissolving in it when required a large proportion of scrap iron.
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 there-
fore claim as the Invention secured to me by the herein-before in part recited
Letters Patent is--
First. The general arrangement and construction of apparatus for the production
of steel and of cast metals, as herein-before described.

page_text: Second. The system or mode of producing steel by means of compressed air forced
into and through a strata of molten metal, such molten metal being at the same
time submitted to the action of heated gases.
Third. Effecting the extraction of phosphorous from cast iron in the manner
herein-before inentioned, by the production of a scorice which shall contain the
impurity or impurities it is desired to remove, and then recarburising the product
in the manner herein-before described.
In witness whereof, I, the said John Henry Johnson, have to this my Speci-
fication set my hand and seal, this Eighth day of September One thousand
eight hundred and seventy-six.
J. HENRY JOHNSON. (L.S.)