IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL AND IN FURNACES TO BE EMPLOYED THEREIN, WHICH FURNACES ARE ALSO APPLICABLE TO THE REMELTING OF METALS GENERALLY
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 STEEL AND IN
FURNACES TO BE EMPLOYED THEREIN, WHICH FURNACES ARE ALSO APPLICABLE
TO THE REMELTING OF METALS GENERALLY."-A communication from
abroad by Francis Ellershausen, of Ottawa, in the Dominion of
Canada, Metallurgist.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition,.
on the 30th March 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 STEEL AND IN
FURNACES TO BE EMPLOYED THEREIN, WHICH FURNACES ARE ALSO APPLICABLE
TO THE REMELTING OF METALS GENERALLY," a communication to me from
abroad by Francis Ellershausen, of Ottawa, in the Dominion of Canada,,
Metallurgist, to be as follows:-
This Invention relates to the manufacture of cast steel from pig
iron in conjunction with wrought iron or iron ore; also to the

page_text: melting of blistered steel and other metals in large quantities, and
in furnaces employed therein.
According to this Invention the furnace is divided into two fire
chambers separated by a fire bridge, the one chamber serving to
contain the crucible which is surrounded by fuel, whilst the other
chamber forms a reverberating fire chamber, the top being so curved
or arched as either to direct the flame round the sides of the crucible
in the adjoining chamber or down into the open mouth thereof as
required. An opening is made in the roof immediately above the
crucible to afford easy access thereto; and a lid or cover, as well as a
discharge hole, are also provided for the crucible, which is of larger
size than usual. In using this furnace, after both fires have been
brought to a white heat, molten cast iron is poured into the crucible in
such quantities as will form steel of the required quality in conjunction
with malleable iron; vitrious fluxes are then introduced in order to
protect the metal from oxidation. Wrought-iron scraps are then
brought to a white heat in an adjoining furnace and introduced in
suitable quantities into the cast iron already in the crucible. When
the cast and wrought iron have been thus mixed and melted together
in the crucible the contents is drawn off as cast steel through the
discharge pipe. This furnace may also be used for the smelting
and refining of blistered or other steel or for the remelting and
refining of metals generally. The puddling process may also be
carried on in the improved furnace by making the working hole on
the top in lieu of on the side of the furnace, the puddling being
effected by means of a ball of iron attached to the lower end of an
iron bar, which is worked up and down inside the crucible by a
pulley and chain or by hand. Pulverized iron ore and purifying
fluxes or agents with pulverized charcoal are added to the cast iron
by degrees through the feed hole and worked up with the metal
until it comes to "nature;" the slag is then run off through the slag
hole, and the required proportion of cast iron to form the required
quality of steel is added. The cover of the crucible is either put on
or vitrious flux added to prevent oxidation of the steel, whilst the
blast is increased in the fire chamber containing the crucible. The
cast iron last added will carbonize the pasty material and the whole
will become liquid, and after allowing sufficient time for fusing the
cast steel is ready for drawing off.

page_text: 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 30th September 1868.
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 Thirtieth day of March, in the year
of our Lord One thousand eight hundred and sixty-cight, in the thirty-
first 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, 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 for
"IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL AND IN FURNACES TO
BE EMPLOYED THEREIN, WHICH FURNACES ARE
APPLICABLE TO THE RE-
MELTING OF METALS GENERALLY," a communication from abroad by Francis
Ellershausen, of Ottawa, in the Dominion of Canada, Metallurgist,
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 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.
ALSO
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 he particularly described and ascertained in and
by the following statement, reference being had to the accompanying
Drawings and to the letters and figures marked thereon, that is to

page_text: The said Invention relates to the manufacture of cast steel from pig
iron in conjunction with wrought iron or iron ore; also to the melting
of blistered steel and other metals in large quantities, and in furnaces
employed therein.
According to this Invention the furnace is divided into two fire
chambers separated by a fire bridge, the one chamber serving to contain
the crucible which is surrounded by fuel, whilst the other chamber
forms a reverberating fire chamber, the top being so curved or arched
as either to direct the flame round the sides of the crucible in the
adjoining chamber or down into the open mouth thereof as required.
An opening is made in the roof immediately above the crucible to
afford easy access thereto; and a lid or cover, as well as a discharge
hole, are also provided for the crucible, which is of larger size than
usual. In using this furnace after both fires have been brought to a
white heat, molten cast iron is poured into the crucible in such
quantities as will form steel of the required quality in conjunction with
malleable iron; vitreous fluxes are then introduced in order to protect
the metal from oxidation. Wrought-iron scraps are then brought to
a white heat in an adjoining furnace and introduced in suitable
quantities into the cast iron already in the crucible. When the cast
and wrought iron have been thus mixed and melted together in the
crucible the contents is drawn off as cast steel through the discharge
pipe. This furnace may also be used for the smelting and refining of
blistered or other steel, or for the remelting and refining of metals
generally. The puddling process may also be carried on in the improved
furnace by making the working hole on the top in lieu of in the side
of the furnace, the puddling being effected by means of a ball of iron
attached to the lower end of an iron bar, which is worked up and
down inside the crucible by a pulley and chain or by hand. Pulverised
iron ore and purifying fluxes or agents with pulverised charcoal are
added to the cast iron by degrees through the feed hole and worked
up with the metal until it comes to "nature;" the slag is then run
off through the slag hole, and the required proportion of cast iron to
form the required quality of steel is added. The cover of the crucible
is either put on or vitreous flux added to prevent oxidation of the steel,
whilst the blast is increased in the fire chamber containing the crucible.
The cast iron last added will carbonize the pasty material and the
whole will become liquid, and after allowing sufficient time for fusing
the cast steel will be ready for drawing off.

page_text: shall now proceed more particularly to describe the same, and for that
purpose shall refer to the several Figures on the annexed Sheet of
Drawings, the same letters of reference indicating corresponding parts
in all the Figures.
Figure 1 of the Drawings represents a side elevation of the improved
furnace; Figure 2 is a horizontal section of the same taken along the
fire-bars on the line A, B, in Figure 1; Figure 3 represents a vertical
longitudinal section of the said furnace; and Figure 4 is a vertical
longitudinal section of a modified form of the roof of the fire chambers
in the said furnace.
a is the shell of the furnace which may be built in the form shewn
in the Drawings of ordinary bricks or stones, but lined on the inside
with fire-bricks; it will be strengthened by an iron casing on the outer
side; b is the principal fire chamber supplied with coke or anthracite
coal, and provided with grate bars c, c, ash-pit d, d, and side door e
through which the fuel and the crucibles are introduced; f is the
outlet from the fire chambers into the chimney g; is a stand for
the support of the crucible built of fire-brick, and of sufficient size for
any convenient dimension of crucible employed; is the crucible
referred to; is a discharge pipe leading from the bottom of the crucible
for running off the steel or molten metal; k is the aperture in the
roof of the furnace immediately above the mouth of the crucible; this
aperture is also made use of for manipulating the material in the
crucible during the process of conversion; p is the cover of the crucible
shown in Figure 4; a suitable hole situate higher up than is
provided in the crucible for discharging the slag; is a second fire
chamber separated from the first fire chamber 6 by the fire bridge m;
this second fire chamber is also provided with the requisite grate bars
and ash-pit, but with an arched roof, as shewn at n; o is the door for
the admission of fuel into the fire chamber, which in this case must
consist of bituminous coal for the purpose of creating a flame. Both
of these fire chambers are supplied with air pipes from a fan blast for
facilitating the combustion.

page_text: from that shewn in the other Figures, being
throwing the flame from the second fire chamber into the mouth of
the crucible, while in Figure 3 the reverberatory fire is to increase the
heat on and around the crucible.
With the foregoing brief description of this Invention I will now
proceed to describe its mode of operation.
By the use of the improved furnace a degree of temperature is
obtained greatly in excess of any degree of heat heretofore produced
in crucibles or reverberatory furnaces used in the manufacture of
steel. Thus a crucible of two inches in thickness, and sufficiently
large to contain one thousand pounds of metal, will convert this quantity
in one half the time now occupied in smelting the metal contained in
a crucible holding about fifty pounds. By this Invention also the
heated crucible will stand for many days' work as its temperature is
not varied, and by tapping the crucible the operation can be continued
without interruption.
In the first modification of furnace shewn in Figures 1, 2, and 3 the
modus operandi is as follows:-After both fires are started, and the
furnace brought to a white heat, molten cast iron is poured into the
crucible in such quantities as will form steel of the required quality
in conjunction with malleable iron. After the introduction of cast
iron vitreous fluxes are introduced in order to protect the metal from
oxidation. Wrought-iron scraps are then brought to a white heat in
an adjoining furnace, and are introduced in suitable quantitics into the
cast iron already contained in the crucible, such introduction being
effected slowly and as fast as the same is melted by contact with the
cast iron. When the proper proportions of cast and wrought iron have
been thus mixed in the crucible, and the proper fusion secured, the
metal is drawn off in the condition of cast steel through the discharge
pipe (Figure 1), and the process is repeated.
The next and important advantage afforded by the improved furnace
is its capacity for smelting and refining blistered or any other steel
or any other metals desired to be resmelted or refined, as this furnace
will perform the same work in less than half the time hitherto required,
and in far larger quantities at each operation.

page_text: In the second modification of furnace shewn in Figure 4 the well-
known puddling furnace is adopted with the following modifications:-
The working hole is on the top of the furnace in place of on the side;
the puddling itself is effected by means of a ball of iron attached to
the end of an iron bar, operated in a vertical direction by a pulley and
chain or by hand. The crucible takes the place of the hearth, and in
doing so the hearth or crucible is heated from the reverberatory fire,
and at the same time assisted by the fire around the crucible, thereby
producing an intense heat. When the interior of the chambers are at
a white heat a quantity of cast iron is introduced into the crucibles,
the puddling process begins, and sufficient quantities of pulverised iron
are mixed with purifying fluxes or agents, and pulverized charcoal
are introduced by degrees through the feed hole K, and worked up
with the melted cast iron until the metal comes to "nature" or
becomes "pasty." The slag is then run off through a slag hole in
the crucible, and the required proportion of cast iron is added to form
the required quality of steel. The cover p is either put on the crucible
or vitreous flux is added to prevent the oxidation of the steel, and the
blast is increased in the fire chamber b. The cast iron last added
will carbonize the pasty material before alluded to, and the whole will
become liquid, and after allowing sufficient time for fusing the cast
steel is ready for drawing off.
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 combination in metallurgical furnaces of two fire chambers
separated by a fire bridge, the one chamber being intended for the
reception of a crucible, and the other constituting a reverberatory fire
chamber, both such chambers being in connection with the crucible,
and working together substantially in the manner and for the purpose
herein-before described.
Second. The process of smelting and refining metals by the employ-
ment of a large crucible provided with a discharge holes, as herein-before
described.

page_text: Third. The puddling of cast iron and producing cast steel therefrom
in a crucible placed in the said improved furnace, and surrounded by
fire, substantially as herein-before described.
In witness whereof, I, the said John Henry Johnson, have to
this my Specification set my hand and seal, the Tenth day of 5
September, One thousand eight hundred and sixty-eight.