IMPROVEMENTS IN THE MANU- FACTURE OF IRON
Year: 1856

page_text: LETTERS PATENT to Richard Albert Tilghman, of Philadelphia, United
States of America, for the Invention of "IMPROVEMENTS IN THE MANU-
FACTURE OF IRON."
Scaled the 4th March 1856, and dated the 2nd January 1856.
PROVISIONAL SPECIFICATION left by the said Richard Albert Tilghman
at the Office of the Commissioners of Patents, with his Petition, on the
2nd January 1856:
I, RICHARD ALBERT TILGHMAN, of Philadelphia, United States of America,
do hereby declare the nature of the Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF IRON." to be as follows:-
It has been heretofore proposed to mix alkaline salts (particularly common
salt), and sometimes zinc ore, with the materials forming the charge of iron
furnaces, for the purpose of improving the quality of the metal. The method
in which these substances have. been applied has been to mix them with the
ordinary charge, and put them in at the top of the furnace, whence they
gradually descend to the bottom; but these substances being volatile at a
red heat, are vaporised in great part by the current. of heated gas, and are
lost before they can act with full effect upon the materials in the furnace.
Now, my Invention consists in introducing substances, such as alkaline
salts (particularly common salt), or zinc, in the state of metal, ore, or salt,

page_text: directly into the lower part of iron furnaces where the materials are already
at a high temperature. The effect of this is, that these substances being
immediately vaporized, diffuse themselves through the whole space, and come
in contact with the whole charge of materials at an intensely high tempera-
ture, and produce their full beneficial result.
These substances may be introduced into the hot parts of the furnace
either in the solid, melted, or gaseous state, as may be most convenient
respectively; but the method I prefer is to pass by suitable machinery a
constant stream of the dry powdered substance into the tuyere or blast pipe
of the furnace, so that the blast shall carry the powder at once into the hotest
part of the furnace.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Richard Albert Tilghman in the Great Seal Patent Office
on the 1st July 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
ALBERT TILGHMAN, of Philadelphia, United States of America, send grecting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of January, in the year of our Lord
One thousand eight hundred and fifty-six, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Richard Albert Tilghman, Her special licence that I, the said
Richard Albert Tilghman, my executors, administrators, and assigns, or such
others as I, the said Richard Albert Tilghman, my executors, administrators,
and 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 IRON," upon the condition
(amongst others) that I, the said Richard Albert Tilghman, my executors or
'administrators, by an instrument in writing under my, or their, or one of
their hands and seals, 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.
NOW KNOW YE, that I, the said Richard Albert Tilghman, do hereby
declare the nature of the said Invention, and in what manner the same is to

page_text: be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say:―
It has heretofore been proposed to mix common salt with the ordinary
charge of iron furnaces, as it is put in at the top of the furnace; but salt being
volatile at a red heat, is vaporized in great part by the current of heated
gas, and is lost before it can act with full effect upon the materials in the
furnace.
Now, my Invention consists in introducing common salt directly into the
lower parts of iron furnaces where the temperature is very high, so that being
there immediately vaporized and diffusing itself into the gaseous atmosphere,
it penetrates into the pores and cavities of the materials, and in consequence
of this great surface of contact at an intensely high temperature, it produces
a more powerful chemical effect.
The salt may be introduced either in the solid, melted, or gaseous form, but
the method I prefer is to feed dry powdered salt in a constant stream into the
blast pipes of the furnace, so that the blast shall carry it at once into the
hottest part of the furnace. The quantity of salt I have used is from about
three per cent. and upwards of the weight of the iron and slag produced, but
I do not confine myself thereto, as the quantity may be varied according to the
nature of the ore and fuel employed. And I would state, as a general rule,
that as the materials used are more highly sulphurous, I employ a larger
quantity of salt.
What I claim as my Invention is, the introduction of common salt into the
hot or lower parts of blast furnaces used in the manufacture of iron.
In witness whereof, I, the said Richard Albert Tilghman, have hereunto
set my hand and seal, this First day of July, in the year of our Lord
One thousand eight hundred and fifty-six.
Witness,
GEO. PITT,
4, Old Square.
R. A. TILGHMAN. (L.S.)