IMPROVEMENTS IN THE MANUFACTURE OF STEEL
Year: 1872

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."-A communication
from abroad by George Francis Wilson, of Providence, Rhode
Island, United States of America.
Sealed the 18th June 1872, and dated the 30th April 1872.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 30th April 1872.
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 STEEL," a communi-
cation to me from abroad by George Francis Wilson, of Providence,
Rhode Island, United States of America, to be as follows :-
This Invention relates to the method of refining cast iron or con-
verting it into steel by the introduction into the molten metal for the

page_text: purpose of desulphurizing, dephosphorizing, and decarbonizing of air,
substantially in the manner practised in the well-known Bessemer
process. This process has heretofore generally been carried out in costly
apparatus, and has been not unattended with danger. The metal had to
be melted in one furnace and then transferred to a separate converting
furnace, which operation was expensive, laborious, and often dangerous,
while the apparatus was liable to get out of order, and delay was fro-
quently incurred in order to make the necessary repairs. It is proposed
to remedy these difficulties by combining the two necessary operations in
one furnace of a peculiar construction and operation.
The converting furnaces being built in connection with the melting
(or gas) furnaces for the purpose of utilizing the waste heat of the latter,
are necessarily stationary; therefore the blast must, as in the "Swedish
process," be introduced at the sides of the hearth; but it is proposed to
remedy the defect of the Swedish process while securing the advantages
connected with this general mode of admitting the blast. The defect
referred to is the irregularity and uncertainty of product in the Swedish
converters consequent upon the necessity of continuing to blow till the
converted metal has been tapped out to a level below that of the tuyere
holes.
It is proposed to avoid this defect by making the channels of ingress
of blast into the converting furnace sufficiently large in cross section to
allow the melted metal to penetrate them without danger of cooling and
consequent clogging. This is effected by so arranging that the wind
chest with its attached tuyere bricks is elevated nearly two feet above
the bottom of the hearth, with the side wall of which it is connected by
an arched passage curving downwards. By this arrangement the blast
need not be turned on till all the iron has been charged, and it may be
turned off as soon as the "blow" is finished, while the blast still enters
the metal in finely divided streams from the tuyere bricks.
The blast entering the furnace only at two opposite sides, the diameter
of the furnace in the direction of the blast should be greater than at
right angles to it.
Two gas furnaces back to back, and with a double-flued chimney at
each end, are arranged to stand between two converting furnaces in such
a manner that their waste heat can be made to go either directly or
through a converting furnace into either chimney, and these gas furnaces

page_text: can be used in either direction, that is, towards one converting furnace or
the other at will, the dampers being so arranged that the gas can be
admitted into the furnace at either end. While the gas and air are
heated before entering these furnaces there are no regenerators employed,
the heating being accomplished in underlying retort furnaces in a
manner generally analogous to the heating of the blast for blast.
furnaces.
The blast furnace may stand behind the gas furnaces at any con-
venient distance to allow the iron from it to be carried in the liquid form
to the gas furnaces. The iron should be tapped from the blast furnace
into a ladle or ladles and weighed. It can then be charged directly into
the door of the nearest gas furnace; but to charge it into the other gas
furnace, the door of which is on the opposite side, the ladle should be
lifted up to a level higher than that of the top of the furnaces, and the
metal charged through a hole in the roof, which can be closed with a
cover at all other times. A ladle could, if necessary, be lifted over the
furnaces, and the metal charged into the door of the second gas furnace.
In order to form a larger platform for the workmen on the top of the
converting furnace, the arched top of the said furnace is finished off with
a rectangular exterior by surmounting the curvilinear sheathing of the
main body of the furnace with a rectangular plate attached to it by
means of angle iron, and cut in its interior to correspondingly curvilinear
form and dimensions.
If pig iron be charged solid into the gas furnaces they become melting
as well as purifying furnaces. It is proposed also to use up scrap iron
and steel in the gas furnaces by adding them to the metal bath. This
will tend to shorten the period of its treatment in the converting
furnace.
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 October 1872.
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.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirtieth day of April, in the year of
our Lord One thousand eight hundred and seventy-two, in the thirty-
fifth 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, 1
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 STEEL," a communication to me from abroad by
George Francis Wilson, of Providence, Rhode Island, United States of
America, upon the condition (amongst others) that I, the said John 1
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 2
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 accompanying 2
Drawings and to the letters and figures marked thereon, that is to
say:-
The said Invention relates to the method of refining cast iron or
converting it into steel by the introduction into the molten metal,
for the purpose of desulphurizing, dephosphorizing, and decarbonizing 3
of air, substantially in the manner practised in the well known Bessemer
process. This process has heretofore generally been carried out in
costly apparatus, and has been not unattended with danger. The
metal had to be melted in one furnace and then transferred to a
separate converting furnace, which operation was expensive, laborious, S
and often dangerous, while the apparatus was liable to get out of
order, and delay was frequently incurred in order to make the necessary
repairs. It is proposed according to this Invention to remedy these

page_text: difficulties by combining the two necessary operations in one furnace
of a peculiar construction and operation.
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 annexed Sheet of
Drawings, the same letters of reference indicating corresponding parts
in all the Figures.
Figure 1 of the Drawings is a longitudinal vertical section of the
combined furnace taken along the line 1-2, in Figure 2. Figure 2
is a plan of the furnace shewing the alternate air and gas channels;
Figure 3 is a transverse vertical section of the converter taken along
the line 3-4, in Figure 1, and Figure 4 is a similar section of the
reducing or heating furnace taken along the line 5-6, in Figure 1.
A is the reducing furnaco and B the converter, the bed of cach
being built upon a suitable arch a or b. The hearth or sole of tho
reducing furnace inclines slightly towards the retort shaped converter,
the bottom of which is considerably lower than that of the heating
furnace A, and the two furnaces are connected by one or more channels
provided with tap holes c through which the molten metal in the
reducing furnace will flow into the converter. These holes are closed
by means of removable plugs of fire-brick or other refractory material,
and arranged in a manner well understood by iron manufacturers, so
that they may be tapped or removed when occasion requires. Tho
air and combustible heated gases required to produce the high degree
of heat needed, are supplied to the reducing furnace through flucs or
conduits C, D, the former being the air flues, the latter the gas flues.
All these flues are supplied with dampers d or valves for regulating
the degree of heat, and they discharge the air and gases into the
reducing chamber through ports f suitably arranged in the upper
part of the chamber, the mixture of said air and gases taking place
in the chamber and setting up intense combustion of the charge in
the furnace. The air and gas flues are arranged alternately and in
pairs, the two flues of each pair being close together, as shown, and
discharging their contents in close proximity so as to effect speedy
3 intermixture of the same. The products of combustion are carried
from the reducing to the converting furnace through flues i, heating
the latter as intensely as may be required. There is also provision
made for the admission of gas and air into the converting furnace,

page_text: in order that the same may be supplied to the converter in caso it
should be found necessary at any time. The valves or dampers and
flues are however so arranged that the products of combustion may
if desired, be turned directly from the reducing furnace into the
chimney E through flues k, without passing through the converting
furnace. The converting chamber is provided with pressure blast
pipes F entering the furnace at or near the bottom, so as to discharge
air into the molten mass therein contained. The top of the retort-
shaped furnace is shaped and constructed to admit of the spectroscope
test being made at this point to determine when tho metal has come
to proper condition. The products of combustion pass from the con-
verter to the chimney through one or more flues . The blast tubes F
are arranged on opposite sides of the converter at or near the bottom
and one end thereof, and the chimney flue or flues in the opposite
end of the converter, at the top or side of the arch. In this way all 1
of the crudo iron is with greater certainty acted on by the air, and a
more uniform conversion of the same into steel is obtained. A furnace
thus constructed is cheap but very efficient. Both operations are carried
on in the same structure and a continuity of operation is secured. After
the reducing furnace has been charged the iron is melted thoroughly, 2
and the molten mass is then permitted to pass through the tap hole
or holes c into the converter, where it is converted into refined iron
or steel, as desired, and as well understood by manufacturers of iron. Tap
holes g, h, are of course formed in the converter, and the metal, after
having been brought to a proper condition is run out from the furnace 2
into suitable moulds. The tap holes are closed with fire-brick held in
place by clamps attached to the ironwork inclosing the body of the
furnace. The converting furnaces being built in connection with the
melting (or gas) furnaces for the purpose of utilizing the waste heat
of the latter are necessarily stationary. Therefore the blast must, as in 3
the “Swedish process," be introduced at the sides of the hearth; but it
is proposed to remedy the defect of the Swedish process, while securing
the advantages connected with this general mode of admitting the blast.
The defect referred to is the irregularity and uncertainty of product in
the Swedish converters, consequent upon the necessity of continuing to 3
blow till the converted metal has been tapped out to a level below that
of the tuyere holes.

page_text: of blast into the converting furnace sufficiently large in cross section
to allow the melted metal to penetrate them without danger of cooling
and consequent clogging. This is effected by so arranging that the wind
chest with its attached tuyere bricks is elevated nearly two feet above
the bottom of the hearth, with the side wall of which it is connected by
an arched passage curving downwards. By this arrangement the blast
need not be turned on till all the iron has been charged, and it may be
turned off as soon as the "blow" is finished, while the blast still enters
the metal in finely divided streams from the tuyere bricks.
The blast entering the furnace only at two opposite sides the diameter
of the furnace in the direction of the blast should be greater than at
right angles to it.
Two gas furnaces, back to back, and with a double flued chimney at
each end, are arranged to stand between two converting furnaces in such
a manner that their waste heat can be made to go either directly or
through a converting furnace into either chimney, and these gas furnaces
can be used in either direction, that is towards one converting furnace,
or the other, at will, the dampers being so arranged that the gas can be
admitted into the furnace at either end.
The blast furnace may stand behind the gas furnaces at any convenient
distance to allow the iron from it to be carried in the liquid form to the.
gas furnaces. The iron should be tapped from the blast furnace into a
ladle or ladles and weighed. It can then be charged directly into the
door of the nearest gas furnace. But to charge it into the other gas
furnace, the door of which is on the opposite side, the ladle should bo
lifted up to a level higher than that of the top of the furnaces and the
metal charged through a hole in the roof, which can be closed with a
cover at all other times. A ladle could if necessary be lifted over the
furnaces and the metal charged into the door of the second gas furnace.
In order to form a larger platform for the workmen on the top of the
converting furnace, the arched top of the said furnace is finished off with
a rectangular exterior by surmounting the curvilinear sheathing of the
main body of the furnace with a rectangular plate attached to it by
means of angle iron, and cut in its interior to correspondingly curvilinear
form and dimensions.
If pig iron be charged solid into the gas furnaces they become melting

page_text: and steel in the gas furnaces by adding them to the metal bath. This
will tend to shorten the period of its treatment in the converting furnace.
While the gas and air are heated before entering these furnaces there
are no regenerators employed, the heating being accomplished in under-
lying retort furnaces, in a manner generally analogous to the heating of
the blast for blast furnaces.
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 Invention secured to me 1
by the herein-before in part recited Letters Patent is,―
First. The combination of the reducing and converting chamber
comprised in one furnace, with the air and gas flues, substantially as
shown and described.
Second. The alternate arrangement in the furnace of the air and gas
flues, substantially as shown and described.
Third. The mode of heating the converter by the introduction therein
of the products of combustion from the reducing furnace, substantially
as shewn and set forth.
Fourth. The combination with and relative arrangement in the con-
verter of the air tuyeres or blast tubes, and the chimney fluo or flues,
substantially as and for the purposes set forth.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and soal this Twenty-ninth day of
1