An Improvement in Blast Furnaces..
Year: 1892

page_text: Date of Application, 20th May, 1892
Complete Specification Left, 25th Nov., 1892-Accepted, 31st Dec., 1892
PROVISIONAL SPECIFICATION.
An Improvement in Blast Furnaces..
We, WILLIAM HAWDON of Holmhurst, Middlesbrough in the County, of York,
Engineer, and RICHARD HOWSON of Southfield Terrace, Middlesbrough in the
aforesaid County, Engineer do hereby declare the nature of this invention to be as
follows:-
It consists of an improved shape of the interior lining. In the ordinary
construction of blast furnaces, the interior lining widens out immediately above
the twyeres into an inverted cone called the bosh, after which the lines are
sometimes carried up parallel for a certain distance, and sometimes drawn in with a
narrowing diameter upwards.
We have observed from experience that the conformation of the lower part of the
furnace as thus constructed is often productive of irregular working, and a gradual
falling off in economy and general efficiency. This is partially due to the entire
weight of the charge resting upon the sloping sides of the bosh, and causing it to
get wedged so tightly as to prevent the descent of the materials, and partially to
the accumulation of scaffolds caused by the materials about the region of the bosh
being in a semi fluid or plastic state, and sticking to the sloping walls.
According to our invention we avoid these risks by raising the inverted cone or
bosh, either entirely or in greater part, to a higher region of the furnace, thus
relieving the lower region from pressure, and at the same time preventing the
formation of scaffolds, owing to the materials in that higher region being still in a
dry and unadhesive state.
The furnace will thus take a form of which any of the following examples may
be recommended in practice.
1st. The diameter of the hearth being fixed. upon, the same diameter may be
carried up to the desired point, which may be half way up the furnace, more or less,
where there is little or no softening of the smelting material. At this point the
bosh commences.
2nd. Instead of the lines preserving the same diameter from the twyeres up to
the diverging point above indicated, they may with advantage be drawn in so as to
narrow the diameter upwards.
3rd. Since the smelting material immediately above the twyeres is usually in a
loose or fluid state, owing to the high local temperature, it is quite admissable to
have a small bosh at this part, the larger, or wider bosh being, as above stated,
much higher up.
4th. The upper bosh may be divided into two or more stages, if it be so desired.
Dated this 19th day of May 1892.
WILLIAM HAWDON.
RICHARD HOWSON.
COMPLETE SPECIFICATION.
An Improvement in Blast Furnaces.
We, WILLIAM HAWDON, of Holmburst, Middlesborough, in the County of York,
Engineer, and RICHARD HOWSON, of Southfield Terrace, Middlesborough, in the
aforesaid County, Engineer, do hereby declare the nature of this invention and in
what manner the same is to he performed to be particularly described and
ascertained in and by the following statement :-
Our said invention consists in giving an improved shape to the interior or interior
lining of blast furnaces.

page_text: In blast furnaces, as hitherto constructed, the interior or interior lining widens
out immediately above the twyeres into the form of an inverted truncated cone
and this conical portion of the interior is usually termed the "bosh," whilst, above
the "bosh," the walls of the interior or lining are sometimes carried up parallel for
a certain distance and then contracted or caused to approach so as to give a
narrowing diameter to the shaft or funnel of the furnace, and, in some cases, the
" to
shaft or funnel is gradually narrowed or contracted from the top of the "bosh
the hopper or mouth.
During a long experience in smelting, we have observed that a furnace of a
conformation, such as, that above described, is often productive of irregular working
and consequently a gradual falling off in the economy and general efficiency of the
furnace, this is partially due to the weight of the entire charge resting upon the
inclined walls of the "bosh" and thereby becoming wedged or compressed so tightly
as to prevent the free descent of such charge, and partly to the formation and
accumulation of "scaffolds" caused by the charge in the region of the "bosh,"
which is in a semi-fluid or plastic state, adhering to the inclined walls of the
" bosh."
Now, according to our invention, we obviate these difficulties by removing the
inverted cone or "bosh" either wholly or in part from the bottom of the shaft or
funnel and immediately above the twyeres to a higher region of the furnace, thus
relieving the charge at the lower part of the shaft or funnel from pressure and
danger of congestion, and, at the same time, preventing the formation of "scaffolds"
in or about the "bosh" inasmuch as the heat of the furnace at the higher region is
not sufficient to liquefy or render plastic the charge, which therefore remains in a
solid and inadhesive state.
And in order that our said invention may be more clearly understood and readily
carried into effect we will proceed, aided by the accompanying drawings, more fully
to describe the same.
DESCRIPTION OF THE DRAWINGS.
Figure 1. is a vertical section of the interior of a furnace of an existing and well
known style.
Figure 2. is a similar view representing a furnace constructed according to our
invention, and,
Figures 3. and 4. are similar views illustrating slight modifications in the appli
cation of our invention.
In the several figures like parts are indicated by similar letters of reference.
Referring to Figure 1., a. represents the shaft or funnel of the furnace,
b. represents the "bosh," c. represents the well or "hearth," d. represents the
openings for the twyeres and e. represents the hopper or mouth which is closed. by
means of a bell f.
In this construction of blast furnaces, which is of the ordinary kind, the interior
or lining widens out immediately above or at the twyeres d. into the form of an
inverted truncated cone b. constituting the "bosh," whilst above the "bosh" b., the
shaft or funnel is slightly tapered or narrowed towards the top at which point
it is contracted to form the hopper or mouth e. and to form a seat for the
bell f.
The walls of the interior or lining are, however, from the "bosh" b., sometimes
carried upward parallel to near the top where a contraction is formed, as befor
explained, to form the hopper e.
During a long experience in smelting, we have observed that a furnace, having a
conformation such as either of those above described, is often productive o
irregular working and consequently a gradual falling off in the economy and
general efficiency of the furnace.
This is partially due to the weight of the entire charge resting upon the inclined
walls of the "bosh" b. and thereby becoming wedged or compressed so tightly a

page_text: to prevent the free descent of the material constituting the charge and partly to
the formation and accumulation of "scaffolds " caused by the charge in the region
of the "bosh" b., which is in a semi-fluid or plastic state, adhering to the inclined
walls of the "bosh."
Now, according to our invention as represented at Figures 2., 3, and 4., we
obviate these difficulties by removing the inverted cone or bosh" either wholly
or in part, from the bottom of the shaft or funnel a. and immediately above the
twyeres d. to a higher region of the furnace thus relieving the charge at the lower
part of the shaft or funnel a. from pressure and danger of congestion, and, at the
same time, preventing the formation of "scaffolds" in or about the "bosh" b.
inasmuch as the heat of the furnace, at the higher region, is not sufficient to liquefy
or render plastic the charge, which latter therefore remains in a solid and inadhesive
state.
Referring more particularly to Figure 2. which illustrates our invention in
perhaps its broadest application, the "bosh" b. is located above a horizontal line
drawn about midway between the mouth or hopper e. and the twyeres d., that is to
say, about halfway up the furnace, more or less, where there is little or no softening
of the material constituting the charge.
Below the "bosh" b. the shaft or funnel a. is formed of the same diameter as the
hearth c., that is to say, the walls of the funnel are formed parallel in continuation
of the wall of the hearth c.
Or, in lieu of forming that part of the shaft or funnel a. below the "bosh" b.
with parallel walls in continuation of the hearth c., the diameter of the hearth at
the twyeres d. may be increased with relation to the diameter of the shaft or
funnel a. at its junction with the "bosh b. either by forming the hearth c. of a
larger diameter than the lower part of the shaft or funnel a., or, by forming the
shaft or funnel a. of gradually increasing diameter from the "bosh". downward
and forming the hearth c. in continuation thereof.
Referring more particularly to Figure 3., a large "bosh" b. is arranged in a
similar position to that shown and described with respect to Figure 2., but, in
addition thereto, a "bosh" 6' of smaller diameter is arranged immediately above
the twyeres d. in a similar position to that occupied by the large "bosh" b. in
Figure 1. whilst the hearth c. is of similar proportions.
We find, in practice, that the portion of the charge located immediately above
the twyeres d., in course of smelting, is usually in a loose or fluid state by reason
of the high local temperature and it is therefore possible to employ the small
"bosh" at that point and this peculiar combination of "boshes" b. and b¹ gives
the most satisfactory results and is the preferred arrangement.
Referring more particularly to Figure 4, the same arrangement of the small
"bosh" and hearth c. is employed as that described with respect to Figure 3,
but, in this example, the large "bosh" b. is divided into two stages or tiers b.
and separated by a cylindrical portion a* of the shaft or funnel a., or, if
desired, the number of such tiers might be increased, as will be readily understood.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. In a blast furnace, forming the "bosh" at a point about midway between the
hearth and the hopper or mouth, substantially as herein shown and described and
for the purpose stated.
2. In a blast furnace, forming the "bosh" in two or more stages or tiers located
about midway between the hearth and the hopper or mouth, substantially as herein
shown and described and for the purpose stated.
3. In a blast furnace, the combination of a large "bosh" located about midway
between the hearth and the hopper or mouth and a smaller "bosh'
" located
immediately above the twyeres, substantially as herein shown and described and for
the purpose stated.

page_text: 4. In a blast furnace, the combination of a large "bosh" divided into two or
more stages or tiers located about midway between the hearth and the hopper or
mouth and a smaller "bosh" located immediately above the twyeres, substantially
as herein shown and described and for the purpose stated.
Dated this 25th day of November 1892.
VAUGHAN & SON,
Agents for the Applicants.