AN IMPROVED FURNACE FOR SMELTING IRON
Year: 1857

page_text: LETTERS PATENT to Charles Coffey Alger, of Newburgh, in the County
of Orange, of the State of New York, of the United States of America,
'for the Invention of "AN IMPROVED FURNACE FOR SMELTING IRON."
Sealed the 15th December 1857, and dated the 13th October 1857.
7.
PROVISIONAL SPECIFICATION left by the said Charles Coffey Alger at
the Office of the Commissioners of Patents, with his Petition, on the
13th October 1857.
I, CHARLES COFFEY ALGER, of Newburgh, Orange County, and State of New
York, of the United States of America, do hereby declare the nature of my
said Invention of "AN IMPROVED FURNACE FOR SMELTING IRON," to be fully
described and ascertained in and by the following description, and the accom-
panying Drawings, of which Figure 1 is a side elevation of said furnace';
Figure 2, an end elevation of it; Figure 3, a plan or top view; Figure 4, a
horizontal section taken through its tuyere passages; Figure 5, a vertical,
central, and longitudinal section of it; Figure 6, a vertical and transverse
section, the same being taken through the tuyure passages on opposite sides
of the furnace; Figure 7 is a horizontal section taken at the top of the
boshes.
Blast furnaces for smelting iron ores have always been constructed of a square,
polygonal, or circular form in their horizontal sections through either the
hearth or crucible, and as it is necessary to the proper working of a furnace
that the blast of air should penetrate the whole charge equally, experience has
demonstrated that with heavy coal, such as anthracite, a diameter or width of
about five feet in the hearth is the maximum limit of capacity for the proper
working of such furnaces in order to make good iron. Even with that

page_text: capacity, a blast from four to five pounds pressure to the square inch (such
depending on the quality of the coal) is necessary, the great weight of this
coal admitting of such pressure. But with lighter fuel, such as charcoal,
bitumenous coal, and coke, which is easily lifted, and the fine particles forced
up the blast and lodged in the boshes, and which therefore does not admit of a
blast of such heavy pressure, the furnace cannot advantageously be made so
large as five feet in width or diameter of hearth, and with the proportions
indicated, the use of a blast of heavy pressure is attended with serious incon-
venience on account of the expansion which the air undergoes in the cavities
or openings of the charge, as such occasions inequality in the distribution of
the body of air. The main objection, however, arises not only from the great
cost of machinery and power to produce and maintain a uniform blast under
such heavy pressure, but from an increased consumption of fuel, all of which
adds greatly to the cost of erecting and running furnaces under such con-
ditions. It is the general belief of intelligent and practical iron masters, that
the relative proportions of the hearth to the boshes should be about as one to
three, and that the diameter of the hearth should not much exceed five feet, to
work with economy and produce the best quality of iron. The product cannot
be increased with economy by increasing the diameter or width of the hearth
much beyond five feet, because that necessitates at times a still greater increase
of pressure beyond five pounds, and such increase of pressure would not only
be attended with a still greater proportional consumption of fuel, but besides
it is liable to injure the quality of the iron, causing all that which is melted at
or near the tuyers to be hard, however well the materials may be prepared.
Besides this difficulty, a blast of over five pounds pressure is liable to injure
the strength of the iron, and if the hearth or crucible is increased in diameter
or width much beyond five feet, whenever the furnace loses its required heat,
which often occurs, a hard mass is liable to form on or about the middle or
back wall of the hearth below the tuyeres, to the great detriment of the
smelting process.
These masses, when once formed, remain for a great
length of time after the furnace is brought back to the temperature required
for making good iron. For the reasons above stated, it has universally been
recognized that there is a practical limit to the capacity of such furnaces, and
although it has long been known that it would be a source of great economy if
the capacity of furnaces could be materially increased in some way, suitable to
the production of good iron, with the blast not exceeding the pressure usually
employed, yet prior to my Invention, no plan, to my knowledge, has been pro-
duced which would accomplish the desideratum. The object of my Invention
has been to produce a furnace for smelting iron, and having a capacity

page_text: materially increased beyond that of furnaces as heretofore constructed, and at the
same time preserving what is recognized as the proper relations of the blast to
the charge. And to this end my Invention consists in making the furnace of
an elliptical or oblong form in the planes of its horizontal sections from and
including the hearth or crucible upwards, and having two mouths (one at each
end of the hearth), and one or more ranges of two or more tuyeres in each of
the two opposite sides, so as to. introduce the blast in the direction of the
breadth of the hearth.
In the accompanying Drawings, A represents the hearth or crucible, which
is of an elliptical or oblong form in the plane of its horizontal section, but in
'all other respects formed in the usual manner. B, B, B, B', B', B', are two
series of tuyere arches or openings, one on each side, and arranged between the
main working arches H, H. To those tuyere arches are fitted tuyeres and
blast pipes, in the usual manner, in order to introduce the blasts in the
direction of the breadth of the hearth. C, C¹, are the dam stones; D, D, the
boshes; and E, the stack, bearing the same proportions to the hearth, so far
as width is concerned, that they do in furnaces of the usual form. F, F, are
arches, one at each end of the working mouths G, G. I contemplate, in some
instances, employing two ranges of tuyeres, one above the other. H, H, are
main arches, leading B, B, B, to smaller or tuyere arches. The boshes as
well as the stack are of an elliptical form, and in all other respects bear the
same relations in form to the hearth that they do in furnaces of the usual
construction. The breadth of the hearth is to be determined by the kind of
fuel and the pressure of the blast, with a view to the quality of the iron to be
produced and economy of fuel, the length of hearth being due to the quantity
of iron which it may be desirable to smelt within a given time.
It will be seen from the above, that on my improved plan, the capacity of
the furnace can be materially increased without changing the relations of the
blast to the charge, a result which cannot be obtained, as I believe, by any
other known, method, thus inducing economy, as it is well known that the
greater the quantity of ore and fuel which can be in preparation and reduc-
tion at one time, the less will the relative cost of the smelting process be, as
the labor and number of the keepers will be much less in proportion to the
product of iron, which under such proportions will produce more soft iron with
less fuel.
My Invention or plan for a furnace may also be used to advantage, either
in whole or in part, in the construction of cupola furnaces.
What I claim as my Invention is an improved furnace constructed
substantially as described, that is, with its hearth or crucible and boshes of an

page_text: elliptical or elongated form, substantially and for the purposes as specified,
in combination with two mouths (one at each end for working and tapping),
and two or more tuyeres at each side, so arranged as to introduce the blast in
the direction of the breadth and for the object as herein-before explained.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Coffey Alger in the Great, Seal Patent Office
on the 12th April 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
COFFEY ALGER, of Newburgh, in the County of Orange, of the State of New
York, of the United States of America, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of October, in the year of our
Lord One thousand eight hundred and fifty-seven, in the twenty-first year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
the said Charles Coffey Alger, Her special licence, that he, the said
Charles Coffey Alger, his executors, administrators, and assigns, or such
others as he, the said Charles Coffey Alger, his 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 Invention
for "AN IMPROVED FURNACE FOR SMELTING IRON ORES," upon the condition
(amongst others) that he, the said Charles Coffey Alger, his executors: or
administrators, by an instrument in writing under his, 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.
F
NOW KNOW YE, that he, the said Charles Coffey Alger,. do...hereby.
declare the nature of his said Invention, and in what manner, the same. is
to be performed, to be particularly described and ascertained in and..by. the
following statement and the accompanying Drawings, of which Figure 1 is a
side elevation of said furnace; Figure 2, an end elevation of it; Figure 3, a plan
or top view; Figure 4, a horizontal, section, taken through its tuyere passages;
Figure 5, a vertical, central, and longitudinal section of it; Figure 6, a

page_text: vertical and transverse section, the same being taken through the tuyere
passages on opposite sides of the furnace; Figure 7 is a horizontal section,
taken at the top of the bosbes.
Blast furnaces for smelting iron ores have always been constructed of a
square, polygonal, or circular form in their horizontal sections through either
the hearth or crucible, and as it is necessary to the proper working of a
furnace that the blast of air should penetrate the whole charge equally,
experience has demonstrated that with heavy coal, such as anthracite, a
diameter of about five feet in the hearth is the maximum limit of capacity for
the proper working of such furnace in order to make good iron. Even with
that capacity a blast from four to five pounds pressure to the square inch
(such depending on the quality of the coal) is necessary, the great weight of
this coal admitting of such pressure. But with lighter fuel, such as charcoal,
bituminous coal, and coke, which is easily lifted, and the fine particles forced
up the blast and lodged in the boshes, and which therefore does not admit of
à blast of such heavy pressure, the furnace cannot advantageously be made so
large as five feet in width or diameter of hearth; and with the proportions
indicated the use of a blast of heavy pressure is attended with serious incon-
venience on account of the expansion which the air undergoes in the cavities
or openings of the charge, as such occasions inequality in the distribution of
the body of air. The main objection, however, arises not only from the great
cost of machinery and power to produce and maintain a uniform blast under
such heavy pressure, but from an increased consumption of fuel, all of which
adds greatly to the cost of erecting and running furnaces under such con-
ditions. It is the general belief of intelligent and practical ironmasters that
the relative proportions of the hearth to the boshes should be about as one to
three, and that the diameter of the hearth should not much exceed five feet,
to work with economy and produce the best quality of iron. The product
cannot be increased with economy by increasing the diameter or width of the
hearth much.beyond five feet, because that necessitates at times a still greater
increase of pressure beyond five pounds, and such increase of pressure would
not only be attended with a still greater proportional consumption of fuel, but
besides it is liable to injure the quality of the iron, causing all that which is
melted at or near the tuyeres to be hard, however well the materials may be
prepared. Besides this difficulty, a blast of over five pounds pressure is liable to
injure the strength of the iron. And if the hearth or crucible is increased in
diameter or width much beyond five feet, whenever the furnace loses its
required heat, which often occurs, a hard mass is liable to form on or about
the middle or back wall of the hearth below the tuyeres, to the great detriment

page_text: of the smelting process. These masses, when once formed, remain for a great
length of time after the furnace is brought back to the temperature required
for making good iron. For the reasons above stated, it has been universally
recognized that there is a practical limit to the capacity of such furnaces, and
although it has long been known that it would be a source of great economy
if the capacity of furnaces could be materially increased in some way, suitable
to the production of good iron, with the blast not exceeding the pressure
usually employed, yet prior to my Invention no plan, to my knowledge, has
The object of my
been produced which would accomplish the desideratum.
Invention has been to produce a furnace for smelting iron, and having a
capacity materially increased beyond that of furnaces as heretofore constructed,
and at the same time preserving what is recognized as the proper relations of
the blast to the charge. And to this end my Invention consists in making
the furnace of an elliptical or oblong form in the planes of its horizontal
sections, from and including the hearth or crucible upwards, and having two
mouths (one at each end of the hearth), and one or more ranges of two or
more tuyeres in each of the two opposite sides, so as to introduce the blast in
the direction of the breadth of the hearth.
In the accompanying Drawings, A represents the hearth or crucible, which
is of an elliptical or oblong form in the plane of its horizontal section, but in
all other respects formed in the usual manner; B, B, B, B', B¹, B¹, are two
series of tuyere arches or openings, one on each side, and arranged between
the main working arches H, H. To these tuyero arches are fitted tuyeres
and blast pipes, in the usual manner, in order to introduce the blasts in the
direction of the breadth of the hearth. C, C, are the dam stones; D, D,
the boshes; and E, the stack, bearing the same proportions to the hearth, so
far as width is concerned, that they do in furnaces of the usual form; F, F,
are arches, one at each end of the working mouths G, G. I contemplate, in
some instances, employing two ranges of tuyeres, one above the other. H, H,
are main arches, leading B, B, B, to smaller or tuyere arches. The boshes as
well as the stack are of an elliptical form, and in all other respects bear the
same relations in form to the hearth that they do in furnaces of the usual con-
struction. The breadth of the hearth is to be determined by the kind of fuel
and the pressure of the blast, with a view to the quality of the iron to, be pro-
duced and economy of fuel, the length of hearth being due to the quantity of
iron which it may be desirable to smelt within a given time.
It will be seen from the above that on my improved plan the capacity of
the furnace can be materially increased without changing the relations of the
blast to the charge, a result which cannot be obtained, as I believe, by any

page_text: other known method, thus inducing economy, as it is well known that the
greater the quantity of ore and fuel which can be in preparation and reduction
at one time, the less will be the relative cost of, the smelting process, as the
labor and. number of keepers will be much less in proportion of the product
of iron, which, under: such proportions,, will produce more soft. iron with
less fuel.
My Invention or plan for a furnace may also be used to advantage, either
in whole or in part, in the construction of cupola furnaces.
What I claim as my Invention is, an improved furnace, constructed sub-
stantially as described, that is, with its hearth or crucible and boshes of an
elliptical or elongated form, substantially and for the purposes as specified, in
combination with two mouths (one at each end, for working and lapping,) and
two or more tuyeres at each side, so arranged as to introduce the blast in the
direction of the breadth of the hearth, and for the object as herein-before
explained.
In witness whereof, I, the said Charles Coffey Alger, have hereunto set
my hand and seal, this Fifteenth day of February, in the year of
our Lord One thousand eight hundred and fifty-eight.
ゆい
City and County of New York, S.S.
On this Fifteenth day of February, in the year of our Lord One thousand
eight hundred and fifty-eight, before me, Horace Andrews, a Notary Public,
in & for said City and County, duly commissioned and sworn, personally
appeared Charles Coffey Alger, signer of the foregoing instrument, and
acknowledged that he executed the same, for the purposes therein named.
In witness whereof I have hereunto set my hand and affixed my official
seal, the day and year first above written.

page_text: thereof a Notary Public, in and for the State of New York, duly commissioned.
and sworn, to whose official acts faith and credit are due.
In testimony whereof,. I do hereunto set my hand and seal of office, at..
the City of New York, this Fifteenth day of February, in the year of..
.our Lord One thousand eight hundred and fifty-eight.
5
Consulate
Seal.
E. M. ARCHIBALD,
H. B. M: Consul.