An Improvement in Blast Furnaces.
Year: 1891

page_text: Date of Application, 5th Jan., 1891
Complete Specification Left, 8th Oct., 1891-Accepted, 14th Nov., 1891
PROVISIONAL SPECIFICATION.
An Improvement in Blast Furnaces.
I, CHARLES COCHRANE of Green Royde, Pedmore near Stourbridge,
Worcestershire, Ironmaster, do hereby declare the nature of this invention to
be as follows:-
In blast furnaces as at present constructed there is always a strong tendency of
the gases to rises in a column at the centre of the furnace charge, instead of being
more or less uniformly distributed throughout the mass, owing mainly to the fact
that the resistance of the furnace charge to the passage of the gases is considerably
less at the centre than at the sides. The result hereof is that by far too great a
proportion of the gases passing off consist of carbonic oxide instead of being
converted into carbonic acid by being brought into effectual contact with the ores
in the upper zone so as to reduce these before descending into the incandescent
zone, as should be the case for an economical working of the furnace.
My present invention has for its object to remedy this defect, and it consists in
interposing in the upper part of the furnace, a fixed impediment to the central
ascent of the gases, thereby causing these to be deflected laterally all round such
impediment and to pass up through the masses of ore situated at the circumference
of the furnace, so that in being thus brought into more extended contact with the
ore before escaping at top, the carbonic oxide gas can more effectually operate
its proper reduction.
The said fixed impediment may be constructed in a variety of ways; thus,
according to one arrangement, it may consist of a conical baffle plate, similar in
form to the conical valve closing the charging hopper at top, and supported at a
certain distance below this, so as to be more or less imbedded in the upper zone of
the furnace charge. Such cone may be supported either by suspension rods from
the top of the furnace or it may be carried by transverse bearers, or by struts or
arched butresses projecting upward at an angle from the sides of the furnace.
According to another arrangement I construct an arch or dome in the upper part
of the furnace, the central part of which is solid brickwork strengthened if
necessary by a metal structure, while all round such central part sufficiently large
openings are formed for the free passage of the descending ore through the arch
or dome.
I prefer to make the upper surface of the baffle of conical shape in order to
facilitate the descent of the ore upon its sloping sides; it may however also be
made of a curved or even flat shape in which case a certain portion of the ore
would accumulate on the upper surface until the slipping angle was attained.
The underside of the battle may be either concave or flat or it may project down-
wards with a convex or conical surface, which would assist in deflecting the rising
central column of gases.
As the zone of the furnace in which I place the said baffle has a comparatively
moderate temperature, the baffle as also its supports may be made of suitable
metal, cast iron, or wrought, either alone or in structural combination-or of metal
combined with firebrick or it may be entirely of firebrick.
Dated this 5th day of January 1891.
ABEL & IMRAY,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
An Improvement in Blast Furnaces.
_I, CHARLES COCHRANE, of Green Royde, Pedmore, near Stourbridge,
Worcestershire, Ironmaster, do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
In blast furnaces as at present constructed there is always a strong tendency of
the gases to rise in a column at the centre of the furnace charge, instead of being
more or less uniformly distributed throughout the mass, owing mainly to the fact
that the resistance of the furnace charge to the passage of the gases is considerably
less at the centre than at the sides. The result hereof is that by far too great a
proportion of the gases passing off consists of carbonic oxide instead of being
converted into carbonic acid by being brought into effectual contact with the ores
in the upper zone so as to reduce these before descending into the incandescent
zene, as should be the case for an economical working of the furnace.
My present invention has for its object to remedy this defect, and it consists in
interposing in the upper part of the furnace, a fixed impediment to the central
ascent of the gases, thereby causing these to be deflected laterally all round such
impediment and to pass up through the masses of ore situated at the circumference
of the furnace, so that in being thus brought into more extended contact with the
ore before escaping at top, the carbonic oxide. gas can more effectually operate its
proper reduction.
The said fixed impediment may be constructed in a variety of ways; thus,
according to one arrangement it may consist of a conical or bell shaped baffle plate
supported at a certain distance below the charging valve so as to be more or
less imbedded in the upper zone of the furnace charge. Such baffle may be
supported either by suspension rods from the top of the furnace or it may be
carried by transverse bearers, or by struts or arched buttresses projecting upward at
an angle from the sides of the furnace.
I prefer to make the upper surface of the baffle of a rounded shape in order to
facilitate the descent of the ore upon its sloping sides; it may however also be
made of a conical or even flat shape in which case a certain portion of the ore
would accumulate on the upper surface until the slipping angle was attained.
The underside of the baffle may be either hollow or flat or it may project down-
wards with a convex or conical surface, which would assist in deflecting the rising
central column of gases.
As the zone of the furnace in which I place the said baffle has a comparatively
moderate temperature, the baffle as also its supports may be made of suitable
metal, cast iron, or wrought, or steel either alone or in structural combination, or
of metal combined with firebrick, or it may be entirely of firebrick.
Figs. 1, 2 and 3 of the accompanying drawings shew the arrangement which I
prefer to employ in carrying out my before described invention.
Fig. 1 shews a vertical section of the upper part of a blast furnace with the
baffle A in position ;
Fig. 2. shews a sectional plan, and
Fig. 3 a part vertical cross section of the baffle to an enlarged scale, shewing the
mode in which it is supported.
The baffle A is in this case made of a bell shape, of cast iron, or other suitable
metal; it is held in a central position below the valve B by means of a box-shaped
wrought iron girder C which passes through corresponding rectangular openings
in the side of the bell, as shown more clearly at Fig. 3. This girder extends
across the blast furnace, and rests in wall boxes built in the walls thereof. In
order to stay it against sinking in the middle in the event of its becoming some-
what overheated, the rectangular wall boxes D through which the girder passes

page_text: are made somewhat higher than the girder, in order to allow of the passage of a
plate C¹ fixed on the two ends of the girder. When the latter has been introduced,
it is raised so as to cause the plates C¹ to fit into recesses D' formed on the upper
sides of the wall boxes and packing plates E are then inserted under the bottom
of the girder, so as to hold it in the said position, in which the plates C¹ abut
against the ends of the recesses, while the girder is free to expand in the
outward direction.
The wall boxes are also made slightly wider than the girder, and the narrow
spaces thus left are packed with suitable stemming F, which is also introduced
at F at top and bottom, thus forming a close joint round the girder and preventing
any escape of furnace gases at those points. Within the box girder is by
preference placed a rolled iron girder G, having for its object to support the
girder C in the event of its sinking somewhat owing to overheating. The ends of
the girder C being left open, a current of cold air will continuously pass through it,
tending to keep it at a moderate temperature, and as the girder G is effectually
protected against the heat by the said current of air, it will always afford a reliable
support for the girder C and bell A. The latter is made in two halves vertically
as shewn, which are bolted together over the girder, being constructed so as together
to form a rectangular hole on each side through which the girder passes as shewn
at Fig. 3.
The bell is prevented from shifting its position on the girder, by angle iron
stops H fixed on the latter.
The bell and girder being situated near the top of the furnace, where the
temperature can be kept comparatively low with due care, they will not be
injuriously affected by the heat.
Figs. 4, 5 and 6 shew respectively a vertical section, plan, and part cross section
of a modification of the first described arrangement in which the girder C is made
of cast iron, the bell A being, made with internal ribs A' by which it rests upon
the girder.
It is supported in addition by the inclined stay pieces I secured by bolts to the
bell and girder.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. The use in the upper part of blast furnaces of a central baffle forming an
impediment to the central ascent of the gases, and causing these to be deflected
laterally so as to pass through the masses of ore round the sides of the furnace,
substantially as and for the purposes herein described.
2. Constructing the baffles referred to in the preceding claim of a bell shape,
supported by a girder or girders passing transversely across the furnace substan-
tially as described with respect to the accompanying drawings.
Dated this 6th day of October 1891.
ABEL & IMRAY,
Agents for the Applicant.