IMPROVEMENTS IN BLAST FURNACES
Year: 1868

page_text: LETTERS PATENT to Charles Cochrane, of Woodside Iron Works,
near Dudley, in the County of Worcester, for the Invention of
"IMPROVEMENTS IN BLAST FURNACES."
PROVISIONAL SPECIFICATION left by the said Charles Cochrane at
the Office of the Commissioners of Patents, with his Petition, on
the 21st February 1868.
I, CHARLES COCHRANE, of Woodside Iron Works, near Dudley, in the
County of Worcester, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN BLAST FURNACES," to be as follows:-
My Invention has reference to that construction of blast furnaces
in which the upper end of the furnace is closed with a feeding valve or
"bell" situated just below the hopper, into which the ore and other
materials for charging the furnace are shot; this valve in being
periodically lowered to allow the charge to pass from the hopper into
the furnace permits a considerable quantity of the combustible gas
issuing from the top of the charge to escape past it into the open air;

page_text: thus occasioning a great loss of such gas, which is of considerable value
for heating purposes.
Now my Invention has for its object to prevent such loss of gas, and
consists in closing in the top of the hopper by means of a cover or
hood, in which are formed several large apertures, through which the
materials are shot into the hopper, which apertures are provided with
covers or doors that are closed down when it is desired to lower the bell
valve for admitting the charge from the hopper into the furnace. By
this means the before-mentioned loss of gas is effectually prevented,
the only loss that can take place during the charging being that small
quantity which rises into the space between the bottom of the hopper
and the cover. The charging doors are by preference arranged so as
all to be opened and closed simultaneously by connecting them by
means of chains passing over pulleys. carried. by standards to a central
balance weight, which weight however only partially balances the
weight of the doors, so that these are opened by drawing down the
balance weight by means of a winch connected thereto by chains, while
in releasing these chains that hold the balance weight down the. doors
will close down by gravity; or any other convenient arrangement may
be employed for opening and closing the doors. The cover is further-
more provided with explosion valves fitting with a sand or water joint
over small openings in the cover,. which valves in opening when any
explosion of gas takes place beneath the cover relieve the latter of the
pressure that results therefrom.
In addition to the great saving of gas effected by my Invention it has
the further advantage of obviating the necessity of maintaining a separate
fire in the stoves or boilers which the blast furnace gas is made to heat,
which fire is necessary with the present arrangement of bell valve,
owing to the cessation of combustion which frequently occurs in
consequence of the great escape of gas upon lowering the valve.
"
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles Cochrane in the Great Seal Patent.
Office on the 18th August 1868.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of February, in the '
year of our Lord One thousand eight hundred and sixty-eight, in the
thirty-first year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Charles Cochrane, Her special licence
that I, the said Charles Cochrane, my executors, administrators, and
assigns, or such others as I, the said Charles Cochrane, my execu-
tors, 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 "IMPROVEMENTS
IN BLAST FURNACES," upon the condition (amongst others) that I, the
said Charles Cochrane, 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 Charles Cochrane, 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, reference being had to the accom-
panying Drawings, and to the figures and letters marked thereon, that is
to say :-
My Invention has reference to that construction of blast furnaces
in which the upper end of the furnace is closed with a feeding valve or
"bell" situated just below the hopper, into which the ore and other
materials for charging the furnace are shot; this valve in being
periodically lowered to allow the charge to pass from the hopper into
the furnace permits a considerable quantity of the combustible gas
issuing from the top of the charge to escape past it into the open air,
thus occasioning a great loss of such gas, which is of considerable value
for heating purposes.
Now my Invention has for its object to prevent such loss of gas, and
consists in closing in the top of the hopper by means of a cover or hood,
in which are formed several large apertures, through which the materials
are shot into the hopper, which apertures are provided with covers or

page_text: doors that are closed down when it is desired to lower the bell valve for
admitting the charge from the hopper into the furnace. By this means
the before-mentioned loss of gas is effectually prevented, the only loss
that can take place during the charging being that small quantity
which rises into the space between the bottom of the hopper and the
cover. The charging doors are by preference arranged so as all to be
opened and closed simultaneously by connecting them by means of
chains, passing over pulleys carried by standards to a central balance
weight, which weight however only partially balances the weight of
the doors, so that these are opened by drawing down the balance weight
by means of a winch connected thereto by chains, while în releasing
these chains that hold the balance weight down the doors will close
down by gravity; or any other convenient arrangement may be employed
for opening and closing the doors. The cover is furthermore provided
with explosion valves fitting with a sand or water joint over small
openings in the cover, which valves in opening when any explosion
of gas takes place beneath the cover relieve the latter of the pressure
that results therefrom.
In addition to the great saving of gas effected by my Invention it
has the further advantage of obviating the necessity of maintaining a
separate fire in the stoves or boilers which the blast furnace gas is
made to heat, which fire is necessary with the present arrangement
of bell valve, owing to the cessation of combustion which frequently
occurs in consequence of the great escape of gas upon lowering the
valve..
But in order that my Invention may be readily understood, I will
now proceed more particularly to describe the manner of performing
the same, and I shall for that purpose refer to the accompanying Sheets
of Drawings which show one arrangement for carrying my Invention
into practice.
Figure 1, Sheet I., shows a plan of the blast furnace cover and its
adjuncts; Figure -2, Sheet II., shows a sectional elevation of the same
on line X, X, Figure 1; and Figure 3, Sheet II., shows a section through
one of the explosion valves. Similar letters of reference indicate similar
parts in each of the figures.
The hopper A of the blast furnace is closed as usual at its lower end
by the bell valve B, which is raised and lowered by means of the rod C
and lever D carried by the girder E and standards F. The upper end'

page_text: of the hopper is closed by the cover G formed of segments bolted
together, as shown, and fitting in between a flange a formed on the
upper end of the hopper; this cover is raised a certain height above
the top of the blast furnace, the central portion thereof being flat, while
the sides incline down towards the edge of the hopper; in these sloping
sides are formed the charging openings H, H, provided with doors I
hinged at i and capable of being opened and closed simultaneously by
the following arrangement:-From each door a chain J (shown in blue
dotted lines) passes up over the pulleys K carried by girders L on the
columns M, and thence over the pulleys N carried by the standards O
down to the central balance weight P, shown in blue lines in Figure 1..
To the under side of this balance weight are attached two chains Q, Q,
which passing down over the guide pulleys R, R, and between other
guide pulleys S, S, are conducted to a windlass. By this means it will
be seen that by hauling in the chains Q the balance weight P will be
drawn down, and thus all the doors I to the charging openings raised
simultaneously into the position shown in dotted lines in Figure 2. The
balance weight P being of such a size as only partially to balance the
weight of the doors, these will of themselves close down simultaneously
as the chains Q are let out from the windlass. Between each two
charging openings H is an explosion valve T fitting into annular sand
troughs U over openings Y in the cover, as shown at Figure 3. The
cover G is also tied down to the hopper A at these points by means of
angle iron stays V. The rod C to the bell valve B passes through a
stuffing box W in the centre of the cover G. In charging the furnace,
the bell valve being closed, the doors I are all raised and the ore and
other materials are tipped through the openings H into the hopper,
after which the doors are again closed and the bell valve is lowered
so as to allow the charge to pass into the furnace. By this it will
be seen that only so much of the blast furnace gas can escape during
the operation of charging as will fill the space. between the bell valve
and the cover G.
Having thus described the nature of my Invention, and in what
manner the same is to be performed, I wish it to be understood that
I do not limit myself to the precise arrangement and details of con-
struction as shown on the accompanying Drawings, as these may be
variously modified without departing from the essential feature of my
Invention, whereby the tops of blast furnaces having bell valves are
closed in by means of covers so arranged with charging holes provided

page_text: with doors that the materials are tipped through the charging holes on
to the bell valve, and the said doors then closed down before the valve
is lowered to allow the charge to descend into the furnace, substantially
as and for the purposes herein-before set forth.
In witness whereof, I, the said Charles Cochrane, have here-
unto set my hand and seal, this Thirteenth day of August, in
the year of our Lord One thousand eight hundred and sixty-
eight.