IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL, AND IN THE PREPARATION OF "FUEL USED THEREIN
Year: 1856

page_text: LETTERS PATENT to Sir, Francis Charles Knowles, of Lovell Hill, in the
County of Berks, Baronet, for the Invention of ""IMPROVEMENTS IN THE
MANUFACTURE OF IRON AND STEEL, AND IN THE PREPARATION OF "FUEL USED
THEREIN."
Sealed the 7th April 1857,andidated the 20th October 1856.
PROVISIONAL SPECIFICATION, left by the said Sir Francis Charles
Knowles at the Office of the Commissioners of Patents, with his Petition,
, on the 20th, October 1856
I, Sir FRANCIS CHARLES KNOWLES, of Lovell Hill, in the County of Berks,
Baronet, do hereby, declare the nature of the said Invention for "IMPROVE.
MENTS IN THE MANUFACTURE OF IRON AND STEEL, AND IN THE PREPARATION OF
FUEL USED THEREIN," to be as follows:-
My Invention consists of three parts:-The first is an improved and more
economical method of preparing fuel, whether from wood, spent tan, peat, or,
coal, the said fuel to be used or admitting of being used in the manufacture of
iron. For this purpose I construct kilns, ovens, or retorts of considerable size,.
capable of containing a large quantity of the raw material to be employed,

page_text: and admitting of being closed up after being charged. These kilns, ovens, or
retorts may be conveniently constructed of fire brick in the usual way. I
do not confine myself, however, to any particular form or material, but the
form must be such as to admit of a pipe or pipes, flue or flues for the intro-
duction of the heated gases, to be presently described, and of other pipes or
flues for the exit of the various liquid products of the consequent dry distilla-
tion, and of the gases which will thereby be evolved, and for the proper
collection of the same, by passing them through such hydraulic and other
pipes as are used in gas works, or some convenient modification thereof,
and for their subsequent cooling, condensation, purification (it required,)
and collection in appropriate vessels, receptacles, and gasometers respectively.
To the pipes both of entrance and of exit I adapt cocks or taps, whereby
the current of the gases and other products may be cut off or diverted at
pleasure while the charcoal or the coke is cooling, ot being discharged, or
otherwise, and I employ a series of kilns, ovens, or retorts as usual, so that
some may be in work while others are out. The kilns, ovens, or retorts
being thus constructed and charged with the raw material, and the entrance
pipes or flues and the exit also being open, I introduce through the former
the heated gases collected from the top of the blast furnace by any of the
modes in use, and which gases issue at a heat of about 1800° Fahrenheit,
and I allow the current of these gases to pass through the kilns, ovens, or
retorts moderately at first until the fuel is dried, afterwards in full force, and
thence into and through the hydraulic to the receivers, purifiers, condensers,
and gasometers. The said furnace gases being incapable of supporting any
combustion, act merely by their heat in producing the requisite dry distalla-
tion, and pass away, afterwards mixed with the gases evolved during the opera-
tion; but after being cooled, purified (if need be), and collected in gasometers,
they form a fuel of great power, applicable in all the subsequent stages of
manufacture, and dispensing entirely with the further use of coal.
I claim the use of any blast furnace, whether actually making iron or not.
In the use of anthracite coal the process under the first head will be limited
to the gradual drying of the coal and the removal of volatile matter, so as
to prevent the peculiar decrepitation to which such coal is liable when
exposed to the heat of the blast furnace.
The second part of my Invention consists of a kiln or furnace for the
conversion of cast iron iuto malleable iron or steel. This is constructed of
fire brick or other refractory materials, and it may be cylindrical, square,
prismatic, or of a truncated, conical, or pyramidal form; it is furnished with
a tap-hole, like other furnaces.

page_text: But what I claim as the essence of this part of my Invention is, the
adaptation of pipes in the interior of the furnace or kiln, which commencing
at the top thereof descend nearly to the bottom, where they are open, so as
to admit of the metal rising within them when the 'furnace is filled with it
in its hot and liquid state. "These pipes are to be made of good fire clay or
some very refractory material, and to their tops are to be: fitted closely the
blast pipes of the blowing engine. When I operate to refine or convert the
metal, I first let in the metal as hot as possible into the kiln or furnace, and
this rising to the same level in the pipes and in the furnace, I turn on the
blast of adequate pressure and I force the same through the surface of the
metal 'downwards, which is refined thereby in the usual way to any required
degree, whether for steel or for iron, according to the time of the operation.
I do not in any way claim the blowing of air on, into, or through .the
melted metal, that being the principle of the present fineries long in use; but
what I do claim is, the above construction of furnace, by which this operation
is to be performed.
The third branch of my Invention consists in the blowing or forcing of pure
hydrogen gas or of carburetted hydrogen gas, either pure or mixed, as
above, with the blast furnace gases, and purified into the melted metal in
any direction whatever, so that the metal and the gasumybe thoroughly
agitated together. The effect is to purify the metal from sulphur and
phophorous, and farther, in the case of the carburetted gases, to give
carbon to the metal, in case in the making of steel the previous operation
of decarbonization should have been carried too far for the particular
quality of steel sought to be produced.
I do not limit this operation to. any particular form of. furnace, but I
recommend the form last described as the:most. simple and convenient in
practice; neither do I limit myself to any special mode of generating the
hydrogen gas used; but as the most.simple, direct, and economical, I adopt
the common mode of passing steam over red-hot iron in a closed pipe or
other vessel which is to transmit it to the metal in the furnace.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Sir Francis Charles Knowles in the Great Seal "Patent
Office on the 18th April 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Sir FRANCIS
CHARLES KNOWLES, of Lovell Hill, in the County of Berks, Baronet, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twentieth day of October, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her
reign, did, for Herself, Her heirs and successors, give and graut unto me,
the said Sir Francis Charles Knowles, Her special licence that I, the said Sir
Francis Charles Knowles, my executors, administrators, and assigns, or such
others as I, the said Sir Francis Charles Knowles, my executors, administra-
tors, 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 AND STEEL, AND IN
THE PREPARATION OF FUEL USED THEREIN," upon the condition (amongst others)
that I, the said Sir Francis Charles Knowles, 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 Sir Francis Charles Knowles,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 thereof, reference being had to the Drawings here-
unto annexed, that is to say:-
My Invention consists of three parts:--The first is an improved and more
economical method of preparing fuel, whether from wood, spent tan, peat, or
coal, the said fuel to be used or admitting of being used in the manufacture of
iron. For this purpose I construct kilns, ovens, or retorts of considerable size,
capable of containing a large quantity of the raw material to be employed,
and admitting of being closed up after being charged. These kilus, ovens, or
retorts may be conveniently constructed of fire brick in the usual I do
not confine myself, however, to. any particular form or material, but the form
way.

page_text: must be such as to admit of a pipe or pipes, flue or flues for the introduction
of the heated gases, to be presently described, and of other pipes or flues for
the exit of the various liquid products of the consequent dry distillation, and
of the gases which will thereby be evolved, and for the proper collection of
the same, by passing them through such hydraulic and other pipes as are used
in gasworks, or some convenientmodification thereof, and for their subsequent
cooling, condensation, purification (if required), and collection in appropriate
vessels,receptacles,and gasometers respectively. To the pipes both of entrance
and of exit I adapt cocks or taps, whereby the current of the gases and other
products may be cut off or diverted at pleasure while the charcoal or the
coke is cooling, or being discharged, or otherwise, and I employ a series of
kilus, ovens, or retorts as usual, so that some may be in work while others are
out. The kilns, ovens, or retorts being thus constructed and charged with the
raw material, and the entrance pipes or flues and the exit also being open, I
introduce through the former the heated gases collected from the top of the
blast furnace by any of the modes in use, and which gases issue at a heat
of about 1800° Fahrenheit, and I allow the current of these gases to pass
through the kilns, ovens, or retorts moderately at first until the fuel is dried,
afterwards in full force, and thence into and through the hydraulic pipes to the
receivers, purifiers, condensers, audgasometers. The said furnace gases being
incapable of supporting any combustion, act merely by their heat in producing
the requisite dry distillation, and pass away afterwards mixed with the gases
evolved during the operation; but after being cooled, purified (if need be), and
collected in gasometers, they form a fuel of great power, applicable in all the
subsequent stages of manufacture, and dispensing entirely with the further
use of coal. In the use of anthracite coal, the process under the first head will
be limited to the gradual drying of the coal and the removal of volatile matter,
so as to prevent the peculiar decrepitation to which such coal is liable when
exposed to the heat of the blast furnace.
I claim, under this first part of my Invention, the passing of the hot gases
from blast furnaces through kilns or coke ovens, so as to coke the fuel placed
therein without consuming the same, and so that the said gases combining with
the gases distilled from the fuel may be collected and employed as a powerful
gaseous fuel,and the liquid product of the distillation also economised and saved.
The second part of my Invention consists of a kiln or furnace for the con-
version of cast iron into malleable iron or steel. This is constructed of
fire brick or other refractory materials, and it may be cylindrical, square,
prisinatic, or of a truncated, conical, or pyramidal form; it is furnished with
a tap-hole, like other furnaces.
But the essence of this part of my Inven-

page_text: tion is, the adaptation of pipes in the interior of the furnace or kiln, which
commencing at the top thereof descend nearly to the bottom, where they
are open, so as to admit of the metal rising within them when the furnace is
filled with it in its hot and liquid state. These pipes are to be made of good
fire clay or some very refractory material, and to their tops are to be fitted
closely the blast pipes of the blowing engine. When I operate to refine
or couvert the metal, I first let in the metal as hot as possible into the kiln
or furnace, and this rising to the same level in the pipes and in the furnace,
I turn on the blast of adequate: pressure, and I force the-same through the
surface of the metal downwards, which is refined thereby in the usual way
to any required degree, whether for steel or for irou, according to the time
"of the operation.
In the annexed Drawing, which: shews the kiln in perspective, P., p, are
the pipes, connected with the blast at P and open at p. M, M, is the level
of the surface of the metal; and T is the tap-hole for withdrawing the
metal when converted.
I do not in any way seek to claim the blowing of aircon, into, or
throngh the melted metal, that being. the principle of the present fineries
long. in use; but what I do claim under this: second part of any Invention
is, the construction of furnace.before described, by which this operation is
to be performed.
The third part of my Invention consists in the blowing or forcing of
pure hydrogen gas or of carburetted hydrogen gas,. either pure or mixed, as
before described, with the blast furnace gases, and purified, into the melted
metal, in any direction whatever, so that the metal and the gas. may be
thoroughly agitated together. The effect is to purify the metal from
sulphur and phosphorous, and further, in the case of the carburetted. gases,
to give carbon to the metal, in case in the making of steel. the previous
-operation of decarburization should have been carried too far for the par-
ticular quality of steel sought to be produced.
I do not limit this operation to any particular form of. furnace, but I recom-
mend the form last described as the most simple and convenient in practice;
neither do limit myself to any special. mode of generating the hydrogen
gas used; but as the most simple, direct, and .economical, I adopt. the
common mode of passing steam over red-hot iron in a closed pipe or other
vessel which is to transmit it to the metal in the furnace.
I claim,under this third part of my Invention, the employment of hydrogen
gas or of carburetted hydrogen.gas; either alone or mixed together, or mixed
with purified blast furnace gases obtained in coking, as herein-before.described,

page_text: for purifying melted iron, by forcing the same through it, as described, and
for preventing it from being burned and wasted by over oxidation from
the air, and for adjusting the required degree of carburization thereof.
In witness whereof, I, the said Sir Francis Charles Knowles, have
hereunto set my hand and seal, this Fourteenth day of April, One
thousand eight hundred and fifty-seven.
FRANCIS CHARLES KNOWLES. (L.S.)