Im- PROVEMENTS IN THE MANUFACTURE OF IRON
Year: 1857

page_text: LETTERS PATENT to Francis Hay Thomson, of Glasgow, in the County of
Lanark, North Britain, Doctor of Medicine, for the Invention of "Im-
PROVEMENTS IN THE MANUFACTURE OF IRON."
Scaled the 11th August 1857, and dated the 21st February 1857.
PROVISIONAL SPECIFICATION left by the said Francis Hay Thomson
at the Office of the Commissioners of Patents, with his Petition, on the
21st February 1857.
J, FRANCIS HAY THOMSON, of Glasgow, in the County of Lanark, North
Britain, Doctor of Medicine, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN THE MANUFACTURE OF IRON," to be as follows, that
is to say :-
This Invention relates to the manufacture and refining of iron either in
the smelting or refining furnace, and it consists in the introduction amongst
> the melted metal of coal gas, carburetted hydrogen, or any other combustible
gas, to be used or applied along with atmospheric air, either hot or cold, as fuel
in the blast or other furnaces in the manufacture of iron, by means of a double
tuyere or nozzle, usually known as a "gas blow-pipe." This treatment of the
iron removes a very large portion of the objectionable matters found in iron,
and the result is a comparatively pure and tough metal. The air and gaseous

page_text: matter may be variously applied by means of the tuyere or blow-pipe nozzle,
but it is preferred to effect the operation upon the fluid metal in the hearth of
the furnace subsequent to its reduction in the usual manner.
The double tuyere or nozzle is in itself a most important feature of the pre-
sent improvements, and it is available both for smelting and refining iron,
whether it is employed for introducing the gaseous matter herein-before
described or not. This Invention also relates to the adoption in the manu-
facture or refining of iron of what is known as the "poling" process in the
manufacture or refining of copper; this is the introduction of polos of green
wood or young trees pressed down amongst the melted metal, the effect of such
introduction being the obtainment of a highly refined and tough iron.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Francis Hay Thomson in the Great Seal Patent Office on
the 21st August 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANCIS
HAY THOMSON, of Glasgow, in the County of Lanark, North Britain, Doctor
of Medicine, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of February, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twentieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Francis Hay Thomson, Her special license that I, the said Francis
Hay Thomson, my executors, administrators, and assigns, or such others
as, I, the said. Francis. Hay Thomson, 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 IRON," upon the condition
(amongst others) that I, the said Francis Hay Thomson, 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.

page_text: NOW KNOW YE, that I, the said Francis Hay Thomson, do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement in writing, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to say:-1
My said Invention relates to the manufacture and refining of iron in the
smelting furnace. Hitherto attempts have been made to get rid of the
impurities in crudo iron by the use of gases known to chemists by the term of
oxygenous gases, that is to say, gases which yield or afford oxygen when brought
in contact with carbonaceous and other matters at a high temperature, to com-
bine with them and pass off as gascous matters. But experience has shown that
in many instances the use of such oxygenous gases is extremely deleterious
and wasting to the materials employed, from the fact that the oxygenous gases
alone or along with an uncombinable gas have been employed, thereby causing.
a too rapid decarbonization, and consequently exhaustion of the substance of
the iron. This is known to me, and has been proved by the experiments of
others; and in order to avoid it, and to obtain a profitable result, I havo
investigated the matter, and have found out that the use of gases known to
chemists under the name of carbonaceous gases are essential for the purpose
in view.
And in order that my said Invention may be properly understood I shall
now proceed to describe the illustrative Figures on my explanatory Sheet of
Drawings, which I have hereunto appended for the purpose of showing certain
modifications under which my improvements may be judiciously carried out in
practice.
Figure 1 on my Sheet of Drawings is a vertical section of a smelting or blast
furnace as ordinarily used in the smelting or reduction of iron ores, but fitted
up with compound or double blowing tuyeres, for the purpose of carrying
out my improvements; Figure 2 on my Sheet of Drawings is a detached
sectional view of this compound or double tuyere, in detail, on an enlarged
scale; Figure 3 is a plan of the tuyere, corresponding. The gaseous matters
may be variously applied, depending of course upon the materials to be
acted on; and whero it is necessary to use two gaseous substances a double
blowing tuyere is preferred. In this arrangement, the ordinary blast tuyere A
has a pipe B fitted within it, such pipe B communicating with a blast or
blowing engine in connection with reservoirs containing carbonaceous or other
combustible gases: These gases I introduce into the molten metal, subsequent
to its reduction, by: the usual-manner, in the hearth of the blast furnace. The
reservoirs might be charged with gases of a known composition, and the

page_text: supply of each regulated proportionally by passages of suitable size; but when
manufacturing iron on a large scale, it would be found troublesome and
expensive to prepare some of the gases, and I have found that a profitable
result is obtained when a carbonaceous gas is diluted to a certain extent.
with atmospheric air, the dilution depending altogether upon the materials to
be acted on. My views have been directed more particularly to the raw
material of iron ore employed in Scotland, and which consists principally of
the well-known ore commonly called "black band," and I have found that
the best results are obtained when carbonaceous gas, commonly called
"coal gas," is blown amongst the molten metal surrounded with a stream of
air in the proportion of one of gas to twelve of air. The use of oxygenous
gases, of which air may be considered one, has failed, owing to the too
rapid combustion and consequent oxidation of the metal; but by the use of
carbonaceous gases mixed suitably or diluted with oxygenous gases, not only
is the decarbonization less rapid, and the oxidation of the iron prevented, but
the silicon, sulphur, and phosphorus are attacked, and combining with some
of the elements resulting from the decomposition of the carbonaceous gases;
are carried off under this combination out of the metal, and the result will
be found to be a much more pure and tougher metal than has hitherto been
the result from any previous application of air or steam alone or mixed, either
in smelting or refining iron.
Another portion of my Invention relates to the application of what is well
known in the copper smelting trade as the "poling" process. In carrying out
this branch of my improvements, the iron is operated upon in its molten con-
dition, and before it has been acted upon by this, the herein-before described
process, or any other process, if the molten metal is run into the hearth of
a refining furnace, the operation proceeds by depositing in the mass of metal
suitable billets of wood, by preference green or unseasoned wood, such as
young trees; this young or green wood is pressed down into and amongst
the melted metal, so as to be entirely beneath the surface thereof, and the
resultant effect of this treatment is, that when the metal is run off it is found
to be of a highly refined and toughened character.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I may observe, in conclusion, that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to, as many variations may be made therefrom without
deviating from the principle or main features of my Invention; thus I
'occasionally vary the arrangement of the double tuyere, so as to make the outer

page_text: portion the carbonaceous gas duct, and the inner portion the oxygenous gas
duct; besides, other arrangements of furnaces than the one I have described,
and other arrangements of apparatus used for regulating the supply of gas,
which may to a certain extent vary the mechanical arrangements, may be
employed.
In witness whereof, I, the said Francis Hay Thomson, have hereunto
set my hand and seal, this Twentieth day of August, One thousand
eight hundred and fifty-seven.
FRANCIS HAY THOMSON. (L.B.)