IMPROVEMENTS IN SMELTING IRON ORE. AND IN FURNACES EMPLOYED THEREIN.
Year: 1870

page_text: LETTERS PATENT to George Fowler, of Basford, in the County of
Nottingham, for the Invention of "IMPROVEMENTS IN SMELTING IRON
ORE. AND IN FURNACES EMPLOYED THEREIN.
Sealed the 13th May 1870, and dated the 9th March 1870.
PROVISIONAL SPECIFICATION left by the said George Fowler at the
Office of the Commissioners of Patents, with his Petition, on the
9th March 1870.
I, GEORGE FOWLER, of Basford, in the County of Nottingham, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
SMELTING IRON ORE, AND IN FURNACES EMPLOYED THEREIN," to be as follows:-
This Invention has for its object improvements in smelting iron ore,
and in furnaces employed therein.
In the manufacture of pig iron from the ore two principle results
must be obtained,―

page_text: (1.) The combination between the iron and oxygen of the ore must be
made to give way to a combination of iron and carbon.
(2.) The silica, alumina, and other earthy minerals must be fused and
separated.
In the deoxidizing of the ore and carburization of the iron carbonic
oxide is the agent. In the separation of the earthy matter a flux aided
by heat is the agent.
These operations are carried out in the modern blast furnace as
follows: The fuel, ore, and flux being fed in together at the top slowly
descend. In the descent they meet with the carbonic acid resulting
from the combustion of the fuel near the tuyeres. The carbonic acid
attacks the carbon, and absorbs from it a sufficiency to convert it into
carbonic oxide. This vapor thus obtained envelopes the ore, effects.
its reduction, and then escapes as a mixture of carbonic oxide and
carbonic acid at the top of the furnace, the proportion being about i
70% of the former to 30% of the latter. It is in the escape of this
carbonic oxide that the waste arises, and it is lessened and not removed
by subsequently burning it in the hot blast stoves and under the
boilers.
According to my Invention I reverse the action of the furnace I
force into it at the top carbonic oxide gas by preference generated by
passing air through ignited fucl in insufficient quantity to effect its
complete combustion. The carbonic oxide gas thus obtained is in a
highly heated state, and as it descends through the iron ore in the
furnace it deoxidizes it and becomes itself in part converted into car-
bonic acid gas. When it arrives at the tuyeres it is brought in contact
with a blast by preference highly heated, and so the combustion of the
remaining carbonic oxide is effected. The heat resulting from this
combustion fuses the metal and the cinder, which fall down to the
hearth of the ¡furnace as in furnaces worked in the usual way. The
gases, which now consist almost entirely of carbonic acid and nitrogen,
are led away laterally at a point immediately above the hearth. They
are caused to pass through one of a pair of Siemens' regenerating
chambers, to which they yield up their heat and then escape into the air.
The air blast enters through another regenerating chamber and these a
chambers are worked alternately as is well understood. Or in other
ways the heat of the escaping gases may be communicated to the blast;

page_text: I prefer to feed some solid fuel into the furnace at the top together
with the ore and flux, so that as carbonic acid gas is produced in the
upper part of the furnace it may be immediately reduced and carbonic
oxide reformed. The blast is so adjusted as to effect a complete or nearly
complete combustion at the tuyeres.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Fowler in the Great Seal Patent Office on
the 9th September 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
FOWLER, of Basford, in the County of Nottingham, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Ninth day of March, in the year of our
Lord One thousand eight hundred and seventy, in the thirty-third year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said George Fowler, Her special licence that I, the
said George Fowler, my executors, administrators, and assigns, or
such others as I, the said George Fowler, my executors, adminis-
trators, 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 SMELTING
IRON ORE, AND IN FURNACES EMPLOYED THEREIN," upon the condition (amongst
others) that I, the said George Fowler, 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 George Fowler, 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 thereof, that is to say:-
This Invention has for its object improvements in smelting. iron ore,
and in furnaces employed therein.

page_text: In the manufactu
must be obtained.
(1.) The combination between the iron and oxygen of the ore must be
made to give way to a combination of iron and carbon.
(2.) The silica, alumina, and other earthy minerals must be fused and
separated.
In the deoxidizing of the ore and carburization of the iron carbonic
oxide is the agent. In the separation of the earthy matter a flux aided
by heat is the agent.
These operations are carried out in the modern blast furnace as
follows: The fuel, ore, and flux being fed in together at the top slowly
descend. In the descent they meet with the carbonic acid resulting
from the combustion of the fuel near the twyeres. The carbonic acid
attacks the carbon and absorbs from it a sufficiency to convert it into
carbonic oxide. This vapor thus obtained envelopes the ore, effects its
reduction, and then escapes as a mixture of carbonic oxide and carbonic
acid at the top of the furnace, the proportion being about 70% of the
former to 30% of the latter. It is in the escape of this carbonic oxide
that the waste arises which it is the object of this Invention to remedy.
According to my Invention I reverse the action of the furnace. I force
into it at the top carbonic oxide gas by preference generated by passing
air through ignited fuel in insufficient quantity to effect its complete
combustion. The carbonic oxide gas thus obtained is in a highly heated
state, and as it descends through the iron ore in the furnace it deoxidises
it and becomes itself in part converted into carbonic acid gas. When it
arrives at the twyere it is brought in contact with a blast, by preference
highly heated, and so the combustion of the remaining carbonic oxide
is effected. The heat resulting from this combustion fuses the metal
and the cinder, which fall down to the hearth of the furnace as in
furnaces worked in the usual way. The gases which now consist almost
entirely of carbonic acid and nitrogen are led away laterally at the point
immediately above the hearth. They are caused to pass through one of
a pair of Siemens' regenerating chambers, to which they yield up their
heat and then escape into the air. The air blast enters through another
regenerating chamber, and these chambers are worked alternately as is
well understood. Or the heat of the escaping gases may be com-
municated to the blast by means of the common hot blast stove. I
prefer to feed some solid fuel into the furnace at the top together with

page_text: the ore and flux, so that as carbonic acid gas is produced in the upper
part of the furnace it may be immediately reduced and carbonic oxide
reformed. The blast is so adjusted as to effect a complete or nearly
complete combustion at the twyeres.
The annexed Drawing illustrates the arrangement which I prefer in
carrying my Invention into effect. a, a, is the carbonic oxide generator;
it is charged with coal by an opening at the top provided with a tightly
fitting cone valve, and air under pressure is forced into it near the
bottom, but in insufficient quantity to complete the combustion of the
fuel into carbonic acid. The gas from the generator is led into the
furnace b at the top, and the furnace is charged by an opening at the
top fitted with a cone valve. I prefer to charge into the furnace
together with the ore and flux about two-fifths of the total weight
of fuel employed, the remainder being used in the gas generator. 1, 1,
are twyeres at which a highly heated blast is introduced to mingle
with the descending current of gas and effect a complete combustion;
2,2, are channels by which the highly heated carbonic acid gas and
nitrogen is led away from the furnace to the pair of regenerating
chambers c, through which it is caused to pass alternately, whilst the
incoming air for the blast passes through the other chamber of the pair
in the ordinary way of working regenerators. A high chimney carries
away from the regenerator the gases when they have become comparatively
cool. 3, 3, is the hearth of the furnace in which the metal and slag
accumulate; the slag is allowed to run out continuously and the metal
is tapped out from time to time. By this arrangement it will be seen
that I convert the fuel into carbonic oxide and hydrogen in a separate
generator. Having got thus far I convey it not to the bottom of the
smelting furnace but to the top where the calcined stone and caustic
lime and a certain proportion of carbon are fed in. No effect is
produced on the lime, but the rich atmosphere of carbonic oxide speedily
acts upon the ore, and as it combines with its oxygen the resulting
carbonic acid takes up sufficient free carbon to reconvert it into carbonic
oxide. As these changes form a regular consecutive series I know
the exact state and position of affairs, and can estimate the quantities
of the different substances required in each. Following the ore in its
descent in the furnace I reach the point where it has parted with its
oxygen, is absorbing carbon, is in contact with unchanged caustic lime
and solid carbon, and is immersed in an atmosphere of carbonic oxide.

page_text: I have now reached the stage for fusion, and having the fuel in the
shape of carbonic oxide and hydrogen all I require is the air necessary
to effect complete combustion; this air the twyeres supply, and the
products of combustion descend and pass away from the furnace at the
level where in present furnaces it now enters it. The fusion of the
iron and slag will occur as at present except that the iron being never
in contact with oxygen the possibility of oxidation is reduced to a
minimum. The escaping gases are heated up to a point somewhat in
excess of the melting temperature of cast iron and will thus carry off
a considerable quantity of heat, and this waste I minimise by inter-
cepting the heat in a regenerator or by a hot blast stove and return it
in the blast to the furnace and gas generator.
I claim as my Invention of improvements in smelting iron ore and in
furnaces employed therein, the smelting iron ore by means of a des-
cending current of carbonic oxide gas permeating the column of ore which
itself is passing downwards through the furnace, air being introduced
into the furnace at a distance from the top to complete the combustion
of the gas, and the resulting carbonic acid and nitrogen being led away
from the furnace near the bottom through a regenerator which abstracts
the surplus heat and returns it to the incoming air.
I also claim the general arrangement of the furnaces for smelting
iron ore, substantially as described.
In witness whereof, I, the said George Fowler, have hereunto
set my hand and seal, this Seventh day of September, in the
year of our Lord One thousand eight hundred and seventy.
AHA
TAT