IMPROVEMENTS IN MECHANICAL PUDDLING FURNACES
Year: 1873

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 MECHANICAL PUDDLING FURNACES."-A communi-
cation from abroad by Charles Pernot, of Paris, in the Republic
of France, Manager.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 27th August 1873.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
3 of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN MECHANICAL PUDDLING FURNACES," a com-
munication to me from abroad by Charles Pernot, of Paris, in the
Republic of France, Manager, to be as follows:-
This invention relates to furnaces for effecting the mechanical puddling

page_text: of iron, and consists essentially in the employment of a moveable inclined
rotating hearth which may be changed at will, and admits of the pro-
duction of both heavy and ordinary charges and of one or more balls as
required, whilst ensuring a uniform heating and a continuous and
homogenous working of the bath.
•
The hearth is provided with a worm wheel on its periphery, to which
motion is imparted by an endless screw or worm for the purpose of
rotating it, and is supported on wheels, or rollers, carried by a truck,
which is moved along a line of rails, carrying the hearth with it when it
is desired to remove the hearth from the furnace. When the hearth is
in its place the joint between it and the fixed portion of the furnace is
maintained firm and tight by means of a lever and counterweight.
In preparing this improved furnace for working it is first heated say
for about six hours until of a sufficient temperature, when the hearth is
prepared with sand, scrap iron, calcareous stones, or ore. Taking scrap
iron as an example, when the furnace has attained a white heat some old
iron is disposed on the hearth and the clear flame is allowed to oxidize
the iron, which melts and forms a bath of a slight depth or thickness.
The furnace is then left to cool to a yellow heat, and the hearth is
rotated so as to cause the latter to be coated uniformly over its bottom
and sides with this primary fusion. This operation is repeated until the
requisite depth or thickness of oxyde is obtained, when after. having
been left to cool the furnace is ready for working.
In proceeding to operate upon a charge of cast iron the furnace is
first reheated to a white heat, and rich scoriæ are charged therein, and
afterwards the cast iron, which is then heated, care being taken to rotate
the hearth in order to move about the pieces of cast iron and heat the
same uniformly. The fusion continues for about half an hour, when the
operation of puddling commences. The hearth is rotated, and the
draught of the furnace is stopped by the damper, the scoriæ become
thick by cooling, and their admixture with the cast iron is effected; a
little heat is then given, and the slow rotation of the hearth is continued.
until the whole of the heat is imparted. The bath is then hot. By
continuing the motion the wrought iron is obtained separated from the
scoriæ, and either in a single bloom or in a number of balls if required
a

page_text: by simply dividing the iron obtained in the furnace with a rabble, and
the ball or balls are then removed from the furnace in the ordinary`
manner.
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 26th February 1874.
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-seventh day of August, in the
year of our Lord One thousand eight hundred and seventy-three, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and succes-
sors, give and grant unto me, the said John Henry Johnson, Her special
license that I, the said John Henry Johnson, my executors, adminis-
trators, 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 MECHANICAL PUDDLING FURNACES," a communication to
me from abroad by Charles Pernot, of Paris, in the Republic of France,
Manager, 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 ascer-
tain 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
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

page_text: I now proceed to describe the means for preparing and starting the
furnace: The operation is commenced by heating, 6 hours being
sufficient to raise the furnace to the temperature necessary for its
preparation, the fettling being effected with either sand, scrap iron,
calcareous stones, or ores. Taking scrap iron as an example when the
furnace has attained a white heat some scrap iron is placed on the hearth
and the flame is left clear or bright in order to oxidize the iron, which
melts and forms a bath of a slight depth or thickness. The furnace is
then left to cool down to a yellow heat in order to cause this primary
fusion to congeal over the bottom of the hearth whilst the latter is being
rotated. By this means the hearth is coated uniformly over the bottom
and the sides. This operation is repeated several times until a suitable
thickness of oxide is obtained; the hearth is then left to cool down and
the furnace is ready for working.
In treating a charge of cast iron the operation is performed in the
following manner :-The hearth having cooled down the furnace is raised
to a white heat, and rich scoriæ are charged therein. The cast iron is
afterwards inserted and heated, care being taken to rotate the hearth in
order to move about the pieces of cast iron and heat the contents
uniformly; the fusion having been continued for half an hour the
operation of puddling then commences. The hearth being rotated and
the draught of the furnace obstructed by means of the damper the
scoriæ thicken by cooling, and their mixture with the cast iron is
effected. A little heat is then imparted, and the slow rotation of the
hearth continued until the whole of the heat required is given. The
bath is then hot. By continuing the motion the wrought iron is separated
from the scoriæ, and the operation terminates in the production of a
single ball, which is removed from the furnace by the ordinary means.
A number of balls may be produced by cutting up in the furnace with
a rabble or other tool the wrought iron obtained.
•
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 by the herein-before in part recited Letters Patent is,
First. A puddling furnace provided with an inclined rotatory hearth,

page_text: substantially as and for the purpose herein-before described and illus-
trated by the accompanying Drawings.
.4
Secondly. The so arranging the apparatus as to admit of the rotatory
hearth being changed at will whilst retaining the fixed part of the
furnace, substantially as herein-before described and illustrated by the 5
accompanying Drawings.
In witness whereof, I, the said John Henry Johnson, have to
this my Specification set my hand and seal, this Twenty-sixth
day of February, One thousand eight hundred and seventy-
four.
1