IMPROVEMENTS IN THE MANUFACTURE OF IRON
Year: 1853

page_text: LETTERS PATENT to George Mackay, of Buckingham Street,
Strand, in the County of Middlesex, Gentleman, for the In-
Sealed the 20th May 1853, and dated the 18th March 1853.
PROVISIONAL SPECIFICATION left by the said George Mackay at
the Office of the Commissioners of Patents, with his Petition,
on the 18th March 1853.
I, GEORGE MACKAY, do hereby declare the nature of the said In-
vention for "IMPROVEMENTS IN THE MANUFACTURE OF IRON " to be as
follows:-
This Invention relates to the use of a furnace, somewhat like a
puddling furnace of the reverberatory kind, but having three hearths
side by side, or a long hearth divided into three working sections, more
or less, and a fire grate divided from them by a fire bridge. Beyond
these hearths there is a chamber or chambers for holding the pulverized
ore and carbon; a small quantity of the latter of which is mixed with

page_text: it. The heat, &c., after passing over the hearths above named, passes
under or around the place containing the pulverized ore, and jets of
hot air are projected downwards from the arch of the furnace on to the
several sections of the hearth.
The operation with this apparatus is as follows:-
A charge of ore, mingled with carbon, is placed in the repository
beyond and above the hearths, which, when heated some time, is
allowed to be discharged upon the rear section or hearth, where it meets
a somewhat exhausted heat, driven by the downward blast directly upon
it. When it has been acted upon somewhat, and becomes pasty, it is
moved forward on to the adjoining hearth, where it is worked under a
blast somewhat more intense, till all the carbonic oxide is burned out of
it, which, under this process, is very rapid; thence it is passed forward
to the next hearth, and so on, if there are more hearths; and it is per-
fected under an intense downward blast, which drives down upon it the
flame as it comes over the fire bridge. The iron is gathered on the
hearth nearest the fire, and a loup is made in the ordinary manner
known to puddlers. This operation is followed up by successive feeds
of ore, as will be well understood.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Mackay, in the Great Seal Patent Office,
on the 17th September 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
GEORGE MACKAY, of Buckingham Street, Strand, in the County of
Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of March, in the year
of our Lord One thousand eight hundred and fifty-three, in the six-
teenth year of Fler reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said George Mackay, Her special licence
that I, the said George Mackay, my executors, administrators, and
assigns, or such others as I, the said George Mackay, my executors,
administrators, and assigns, should at any time agree with, and no

page_text: 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
5 THE MANUFACTURE OF IRON," being a communication from abroad, upon
the condition (amongst others) that I, the said George Mackay, 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.
NOW KNOW YE, that I, the said George Mackay, 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, reference being had to the drawings here-
unto annexed, and to the letters and figures marked thereon (that
is to say):
This Invention consists in an improved method of decarbonizing the
iron orc after it has been through the process of deoxidation, and
thereby of reducing it at once from the ore to malleable iron. To effect
this a blast of atmospheric air, cold or hot, is brought upon the ore,
regulated according to the state the ore is in, and the heat required;
the effect of which is to drive out the carbon and other impurities.
The blast is brought down upon the ore from above, either at the
roof or sides of the furnace, as is found most convenient; and thus an
intense heat is created upon the right point, not unlike the action of a
blow-pipe when used in laboratory experiments. In the manufacture
of iron of the malleable kinds, it is well known that the oxide of
which the ore is composed must be treated with carbon to deoxidize it
in the common way; this is done in the blast furnace employed for
converting the ore into pig iron, and the metal is then taken to a
puddling furnace; and after the carbon is driven out it "comes to
nature," as it is called. The impurities are separated, and the pure iron
is gathered into a loup; and under a trip hammer, or other analogous
device, it is formed into a "bloom," ready for the market. This is, how-

page_text: ever, a long and tedious process, and involving great expense; but, by
the present Invention, it is proposed to obtain the malleable iron
directly from the ore, without the intervention of a blast furnace.
To enable others to carry out this Invention, I proceed to describe the
apparatus which has been successfully employed for this purpose. Tu
the accompanying drawing, Fig. 1, shews in longitudinal section a
reverberatory furnace. Fig. 2, is a sectional plan of the same, taken in
the line, 1, 2, of Fig. 1; and Fig. 3, is a top view of the furnace. u, is
a fire chamber; a', the grate; b, is a fire bridge, built of fire-brick, over
which the heat and products of combustion pass to the first or balling
hearth c; thence it passes over the second and third hearth, and, if
necessary, to others beyond; all placed upon the same level, or other-
wise. Thus far, the furnace may be considered like many others, but
the important difference is, that at one or more of the successive hearths
a blast of cold or hot air is introduced, and made to impinge directly
upon the ore in its various stages of progress towards a perfect malle-
able iron.
The mechanical means to effect this may be described as follows,
referring to the drawing for illustration:-
A pipe d, is placed across the top of the arch, from which several
short pipes or tuyers are projected downward through the arch; or the
blast may be introduced from the pipe d, through an oblong opening,
and precipitated in a thin sheet directed upon the loup or carbonized
ore to produce the effect before indicated.
This must not be mistaken for or connected in any way with the
plans devised for the introduction of a blast of air into the furnace to
effect a more perfect combustion of fuel. The intention, however, of
the present device is quite different, namely, to decarbonize the
ore, &c., by means of which a very pure malleable iron is produced
directly from the ore. An arrangement of pipes similar to that shewn
at d, is introduced just over the second hearth at e, for producing a
second downward blast, and in like manner a third arrangement of
pipes f, is added, or more may be employed to the extent found re-
quisite, depending somewhat upon the ore and other causes. To heat
the blast a pipe may lead from the blower to the blast pipes d, e, &c.,

page_text: through the fire bridge, or the air may be heated in any other con-
venient way; the cold blast is introduced directly from the blower, in
the common way.
In place of the ordinary arrangement for the doors of the hearth, by
the use of which some inconvenience has been experienced in the
handling of the ore, the furnace is provided with but one door to each
hearth, and these are placed alternately on opposite sides, by which
means sufficient space for working is obtained, as well as convenient
access to the ore during the process.
Another device which may be found important is to make the hearth
hollow (as at g, in the drawing), and to cause cold air to pass under it
to prevent its burning out, which it would otherwise do very rapidly under
the action of a down blast. This arrangement will also afford a means
of heating the air used for the blast by connecting the blast pipes in
any convenient way with the air passages under the hearth.
The mode of operating according to this Invention is as follows:-
The pulverized ore, mixed with a due proportion of carbon according
to the kind of ore, as well known, is placed upon a table heated by
flucs, as hercin-after described, in large quantities, where it remains till
wanted; thence it is let in upon the first hearth, and the process of
burning out the carbon from the metal commences, and is carried on as
rapidly as is allowable, by directing the downward blast, either hot or
cold, upon it, regulated by a valve in the ordinary way of blast pipes.
The hot or cold air thus blown down through the burning gases
rapidly absorbs the carbon, and refines the ore by driving out the
impurities. This process is carried on during the progress of the ore
to the balling hearth, the heat upon the ore being gradually increased
as the ore is worked forward to the second hearth, where the process is
nearly or quite completed. The decarbonized ore is next brought
forward upon the balling hearth, under the blast proceeding from the
arrangement of pipes d, where the loop is rapidly formed and refined.
It will be understood that the processes upon each hearth are simulta-
neous, and that the manufacture is therefore continuous after it has
commenced.

page_text: The iron ore, after being pulverized and intimately mixed with
carbon, is thrown into a hopper n, at the upper end of a table o, upon
which the ore falls, and is spread out to a depth of three inches, more
or less. This table o, is slightly inclined in its position towards the
rear hearth, over the rear end of which there is an opening at p, below
the roof of the furnace, through which the ore is thrown down on to the
hearth, where the first process of decarbonizing commences. The table
forms the upper side of the flue 7, leading directly from the furnace to
the stack. This flue is made to run under the table in a zigzag
course, so that the escaping gases of combustion may yield up their
heat as much as may be, before entering the chimney. The table o,
may be covered with the roof, as shewn in the drawing, but should not
exclude atmospheric air, and it is always open to the furnace. It not
being necessary, in this improved process, to exclude the products of
combustion, the greatest facility in manipulating is thus gained, as well
as expedition, in following up the successive operations. After the ore
reaches the rear hearth, it is worked forward to the balling hearth, as
before clearly set forth. The manipulations on this table are to spread
the ore by a "firgin," or other well known tool, and to push it down,
when in a proper state, on to the first hearth of the reverberatory
furnace.
When a cold blast is wanted, a pipe leads directly from the blower
to the pipes d, c. f, above the arch of the furnace; and if a hot
blast is used, the course of the blast must pass to the pipes d, e, f,
through the bridge wall, or some other heating apparatus. As these
devices are obvious, and well known to all practical workmen in iron,
they need no further illustration.
Having thus fully described the Invention of Improvements in the
Manufacture of Iron, as communicated to me by my foreign corre-
spondent, I wish it to be understood that, under the above in part
recited Letters Patent, I claim forcing down upon the iron ore, from
the roof of the furnace, in the different stages of the process, as
required, and on the different hearths, atmospheric air, either heated
or coal, for the purpose of decarbonizing the ore, and bringing the iron

page_text: to nature, or refining the same, and regulating the degree of heat,
substantially in the manner and for the purpose herein described.
In witness whereof, I, the said George Mackay, have hereunto
set my hand and seal, the Seventeenth day of September, in
the year of our Lord One thousand eight hundred and fifty-
three.
GEO. MACKAY. (L.B.)