IMPROVEMENTS IN BLAST FURNACES AND IN. OBTAINING A HOT BLAST FOR THE SAME
Year: 1868

page_text: LETTERS PATENT to John Watson, of Seaham Chemical Works, near
Sunderland, in the County of Durham, Manufacturing Chemist,
for the Invention of "IMPROVEMENTS IN BLAST FURNACES AND IN.
OBTAINING A HOT BLAST FOR THE SAME."
Sealed the 19th February 1869, and dated the 22nd August 1868..
PROVISIONAL SPECIFICATION left by the said John Watson at; tho
Office of the Commissioners of. Patents, with his Petition, on the
22nd August 1868..
I,, JOHN WATSON, of Seaham Chemical Works, near Sunderland, in the
County of Durham, Manufacturing Chemist, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN BLAST FURNACES AND*;
IN OBTAINING A HOT BLAST FOR THE SAME," to be as follows:-
My Invention consists, firstly, in contracting the blast furnace at one
or more elevations, whereby a support is afforded to the superincumbent.
mass, which prevents. an undue pressure. on the materials in the lower
part thereof, and thus avoids the existence of a dense mass, through which.

page_text: the air has to pass, and by the same means the upper part of the
furnace is considerably increased in internal capacity.
Secondly. I propose to raise the temperature of air which is forced
into blast furnaces by heat arising from gases or other fuel which has
been used for raising steam or other purposes. As practised at present
the air is supplied from tubes which are heated by ignited gas or other
fuel playing upon their surfaces, and it is also the practise to economise
the fuel used in blast furnaces by using the heat arising therefrom
for the production of steam. According to my Invention I use heat
derived from the furnace for the purpose of obtaining a hot blast,
but instead of using the gases direct I conduct them in the first
instance to the steam boiler as now in use, but in place of allowing
the remaining heat to pass off by the chimney I apply it to the
purpose of heating air for the blast. Or instead of using the said
gases in the first instance for raising steam I employ them for
any other ordinary intermediate purpose. Or instead of the above-
described arrangement I employ for the aforesaid purpose the waste
heat arising from steam boilers which are fixed separately from the blast
furnace.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Watson in the Great Seal Patent Office
on the 22nd February 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
WATSON, of Seaham Chemical Works, 'near Sunderland, in the County of
Durham, Manufacturing Chemist, send greeting:
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of August, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself; Her heirs, and successors, give
and grant unto me, the said John Watson, Her special license that
I, the said John Watson, my executors, administrators, and assigns,
or such others as I, the said
my executors, adminis-
trators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein

page_text: 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, AND IN OBTAINING A HOT BLAST FOR THE SAME," upon the condition,
amongst others, that I; the said John Watson, 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 John Watson, 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 and accompanying Drawings, that is to say:-
The first part of my Invention is shewn at Fig. 1, which represents a
blast furnace constructed according to my improvements in vertical
section. The masonry of the furnace is at a, and at 6 is the aperture
for the escape of the gases; at c is the conical hopper through which
the materials are fed, and at d the usual stopper to be raised or lowered
by a chain or similar contrivance, as now adopted. According to the
ordinary method of constructing blast furnaces they are built vertically
or are gradually tapered inward towards the upper part thereof from the
point e or above the bosh, but according to my Invention I commence at
the point e or above the bosh to taper the internal capacity outward, as
from e to f. After this I continue the furnace by parallel lines f, g, and
then commence another tapered portion g, h, succeeded by a second parallel
parti. By these means it will be evident that the internal capacity of
the furnace is much increased, while at the same time the superin-
cumbent mass is sustained by the inclined parts and prevented in great
measure from bearing upon the material below, thereby avoiding a
crushing effect upon the softer parts of the charge and allowing an
easier access of air through the mass. In the illustration of my
Invention which I have given the masonry is carried outward at k, by
which means I obtain a greater internal capacity at the upper part, but
the exterior walls may be continued without this projection if desired.
I have also described two tapered parts e, f, g, h, but more or one only
of such slopes may be adopted. Care should be taken not to make the
first hopper-formed part e, f, of the furnace too near the tuyeres or hearth,.

page_text: so that they may not be within the melting or "softening" zone of the
furnace, in which case the materials might adhere to the sides and form.
an arch or "scaffold," as it is technically termed.
The second part of my Invention is shewn at Fig. 2, in which 7 represents
a portion of the flue of a steam boiler, in which is placed one or a series
of tubes m, say thirty feet each in length, connected together, if more
than one be used, by U-formed or other connecting pipes n in order to.
counteract the effect of expansion, as is well understood when such tubes.
are applied to other purposes. The products of combustian from a
steam boiler, the furnace of which has been fired with gases generated
in a blast furnace, pass through the space l, and therefore surround the
tubes m. Through these tubes the air intended to be used for the hot
blast is passed by a blast engine or fan in the ordinary manner, and
during its passage it becomes heated by the products of combustion
conducted from the boiler furnace, after which it passes to the blast
furnace to be used in the ordinary manner. Should it be found that
the heat is not sufficiently taken from the flue la pipe extending from
the last tube m may extend upward in the chimney, and then pass
downward to the air trunk leading to the blast furnace, or it may pass
through an ordinary heating stove. I have described tubes of a certain
description as applied to the boiler flue, but any ordinary similar
apparatus may be adopted. Thus far I have alluded to this part of my
.Invention as applied to heating air for the hot blast by means of products
of combustian derived from steam boilers which have been fired by gases
from blast furnaces, but it is also applicable to using the heat which arises
from any other process or apparatus which has been fired by the blast
furnace gases, and which is intermediate between the said blast furnace
and the apparatus for heating the air therefor. This arrangement will
be more readily understood by reference to the diagram Fig. 3.
Having thus described and ascertained the nature of my said Invention,
and the manner in which the same is to be performed, I desire it to
be understood that I claim as secured to me under the above recited
Letters Patent,-
Firstly. As applied to blast furnaces, constructing them with one or
more tapered portions above the bosh and extending outward.
Secondly. Obtaining a hot blast by heating air through the medium
of otherwise waste heat arising from furnaces of steam boilers which have
been fired by gases arising from blast furnaces, or by heat arising from

page_text: any other apparatus or process fired by the said gases, and which is
intermediate between the blast furnace and apparatus for heating
the air.
In witness whereof, I; the said John Watson, have hereunto
set my hand and seal, this Twentieth day of February, in
the year of our Lord One thousand eight hundred and sixty-
nine.