IMPROVEMENTS IN THE MANUFACTURE OF IRON
Year: 1856

page_text: LETTERS PATENT to Robert Mushet, of Coleford, in the County of
Gloucester, Metallurgist, for the Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF IRON."
Sealed the 30th December 1856, and dated the 16th September 1856.
PROVISIONAL SPECIFICATION left by the said Robert Mushet at the
Office of the Commissioners of Patents, with his Petition, on the 16th
September 1856.
I, ROBERT MUSHET, of Coleford, in the County of Gloucester, Metallurgist,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF IRON," to be as follows (that is to say) :-
My said Invention consists in the use or application of combustible car-
bonaceous matters, together with air or blast, in decarbonizing or purifying
iron.
When air or blast is used in the decarbonizing or purifying iron it has a
tendency to oxydise the iron or a portion of it, and my improvements consist
in the introduction into the furnace or vessel containing the melted iron to
be decarbonized or purified of a quantity of carbonaceous fuel or matter
sufficient to prevent or counteract the excessive oxydation of the iron, and
also for the purpose of making the iron more tough and malleable. This
I prefer to effect by introducing the carbonaceous fuel or matter together
with the air or blast, the carbonaceous fuel or matter being powdered, so

page_text: as to pass through a tuyere with the blast or air into the furnace or vessel
containing the iron; but the carbonaceous fuel or matter may be thrown upon
the top of the iron, or otherwise introduced into the purifying furnace or vessel,
during the process.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Mushet in the Great Seal Patent Office on the
16th March 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
MUSHET, of Coleford, in the County of Gloucester, Metallurgist, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of September, 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 grant unto me, the said
Robert Mushet, my executors, administrators, and assigns, Her special licence
that I, the said Robert Mushet, my executors, administrators, and assigns,
or such others as I, the said Robert Mushet, 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 Inven-
tion for "IMPROVEMENTS IN THE MANUFACTURE OF IRON," upon the condition,
amongst others, that I, the said Robert Mushet, my executors or adminis-
trators, 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 Robert Mushet, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement :-
My said Invention consists in the use or application of combustible car-
bonaceous matters, together with air or blast, in the decarbonizing or purifying
of iron.
When air or blast is used in the decarbonizing or purifying of iron, in the

page_text: manner described in the Specification of the Patent granted to Joseph Gilbert
Martien, dated the Fifteenth day of September, One thousand eight hundred
and fifty-five, it has a tendency to oxidize the iron or a portion of it, causing
a considerable waste of the iron during the process. And my improvement
consists in the introduction of a quantity of carbonaceous fuel or matter into
the furnace or vessel containing the molten iron to be decarbonized or purified,
for the purpose of preventing, counteracting, or diminishing the excessive
oxidation of the iron during the process of forcing the air or blast into, through,
and amongst the particles of melted cast iron whilst they are being decar-
bonized or purified, and likewise for the purpose of making the iron more
tough and malleable when purified.
I will now describe the mode which I prefer to adopt in carrying my Inven-
tion into operation for the purposes aforesaid.
When it is found to be convenient to introduce the carbonaceous fuel or
matter through the blast pipes and tuyeres into the purifying furnace or vessel
during the purifying operation, I reduce the carbonaceous fuel or matter to a
fine powder, and having placed it in a receptacle or receptacles attached to
and opening into or communicating with some one or more of the blast
pipes which convey the air into the tuyere pipes of the purifying furnace or
vessel, I cause the carbonaceous dust or powder to fall or pass from the
receptacle or receptacles into these blast pipes in a moderate and uniforin
stream, so that it may be carried along by the current of blast through the
pipes and tuyeres into and amongst the melted iron in the purifying furnace
or vessel. A receptacle may consist of a cylinder, accurately fitted with a
piston, which, when the cylinder is filled with carbonaceous matter finely pul-
verized, at the commencement of the operation may be made to pass down or
along the cylinder by the gradual action of a screw or similar means, so that
the powdered carbonaceous matter may be slowly, evenly, and uniformly pushed
out of or caused to fall from the cylinder into the blast pipes during the time
occupied in decarbonizing or purifying the molten iron; but I do not make any
separate claim to this method of introducing the carbonaceous matter into the
purifying vessel or furnace, and which may be done in any convenient manner
whatever.
The combustible carbonaceous matter employed in carrying out my Inven-
tion may be coal, coke, or charcoal of any kind, or any charred substance
of a carbonaceous composition reduced to a fine powder, and as free as
possible from sulphur and phosphorus, and I prefer to use coal dust from the
purest bituminous coals, producing much flame, and which should be as free
as possible from sulphur ; likewise charcoal dust or dried wood. reduced to fine

page_text: dust, or charred peat dust, or peat dried and pulverised; and I prefer to intro-
duce a constant stream of the carbonaceous dust into the purifying furnace
or vessel during the whole time that the molten cast iron is undergoing the
process of decarbonization or purification by having air blown into or through
it. The quantity of carbonaceous dust to be thus introduced into the puri-
fying furnace or vessel may vary in a general way from about five pounds to
about ten pounds for every one hundred pounds of the molten iron contained.
in the purifying furnace or vessel, care being taken in every case that the
quantity of carbonaceous matter used shall be sufficient to prevent the waste of
the iron by oxydation as much as practicable. The carbonaceous fuel or matter
may, however, be thrown upon the top of the melted iron, or otherwise intro-
duced into the purifying furnace or vessel, during the process. Thus, when it
is not convenient to introduce the carbonaceous matter or fuel into the purify-
ing furnace or vessel by passing it through the blast tubes or tuyeres, it may be
effected as follows:-I fill or partly fill the purifying furnace or vessel (through
any convenient opening) with such combustible carbonaceous matter as afore-
said, either in lumps or otherwise, and when this carbonaceous matter has been
ignited, and has subsequently been brought into a state of intense combustion.
by the blast passing into the purifying furnace or vessel through the tuyeres,
I next run into the purifying furnace or vessel, through a suitable opening
in its side or top, the molten cast iron which it is intended shall be purified or
decarbonized therein, and which molten cast iron may be run in either from a
blast furnace or cupola, or from a ladle, or in any other convenient manner.
The iron is now to be purified or decarbonized by blowing air through it, as
before mentioned, or in any other convenient manner, the object being that
the superincumbent mass of ignited carbonaceous matter may protect the iron
from waste and loss by oxidation, and prevent, counteract, or diminish the
violent eruptions of cinder or slag, which usually occur when cast iron is purified
or decarbonized by blast or air being forced through and amongst its particles
without the addition of carbonaceous fuel or matter in the purifying vessel
during the process.
I do not claim the use of carbonaceous matters or fuel when iron is
refined or purified by blasts of air directed upon the surface of the molten
iron covered with coke or other fuel as in the old refining process, but
solely the use of carbonaceous matter or fuel to be introduced into furnaces
or vessels when cast iron is decarbonized or purified by forcing currents of air
into and through it, either according to the Invention described in the said
Specification of the said Joseph Gilbert Martien, or in any similar or con-
venient manner.

page_text: The carbonaceous fuel or matter may likewise be introduced into the puri-
fying furnace or vessel from time to time, during the operation of decarbonizing
or purifying molten cast iron, through an opening or openings left in the top or
sides of the purifying furnace or vessel, and upon or amongst the molten iron
in any convenient manner.
Having thus particularly ascertained and described the nature of my said
Invention, and the manner in which it is to be performed or may be carried
into effect, I declare that I do not claim as of my said Invention any appa-
ratus herein mentioned, nor do I claim any particular mode of blowing air
into or through the melted iron, so long as the melted iron is decarbonized or
purified by air being caused to pass through it; and that what I do claim is,
the use or application of combustible carbonaceous matters together with air
or blast in the decarbonizing or purifying of molten cast iron, by introducing
such combustible carbonaceous matters into the furnace or vessel containing
such molten cast iron during the process of decarbonizing or purifying it,
for the purpose of preventing, counteracting, or diminishing the excessive
waste of iron which takes place during such process of purification and
decarbonization when no such addition of carbonaceous matter is made to the
molten iron, and also for the purpose of rendering the iron where decarbonized
or purified more tough and malleable.
In witness whereof, I, the said Robert Mushet, have hereunto set my
hand and seal, this Eleventh day of March, in the year of our Lord
One thousand eight hundred and fifty-seven.
Witness,
MAXWELL MUSHET,
Coleford, Gloucestershire.
JOHN LOCKE, Clerk to Mr. Rob Mushet,
Coleford, Gloucestershire.
ROBT MUSHET. (L.S.)