Improvements in Furnaces, such as Cupola and Blast Furnaces.
Year: 1889

page_text: Date of Application, 16th Oct., 1889
Complete Specification Left, 14th July, 1890-Accepted, 23rd Aug., 1890
Improvements in Furnaces, such as Cupola and Blast Furnaces.
I, FRANCIS EDWARD Ross, of No. 10 Whitehorse Road, Croydon, in the County
of Surrey, Civil Engineer, do hereby declare the nature of this invention to be as
follows:-
-
This invention relates to improvements in furnaces of the kind in which a con-
siderable height or mass of fuel mixed with metal or ore, is maintained upon the
furnace hearth; such for example as cupola and blast furnaces. The hot gases and
products of combustion that escape from the upper part of such furnaces usually
contain a large proportion of combustible gas such as carbonic oxide, and the object
of this invention is to utilize this heated combustible gas or a portion thereof by
causing it to be withdrawn from an upper part of the furnace and to re-enter the
furnace at a lower part thereof where it is completely.burnt. By this means furnaces
of the kind mentioned can be worked in a more economical manner than usual.
The jets of air usually blown into the lower portions of furnaces of the kind
mentioned may advantageously be utilized to induce the hot gases or incomplete
products of combustion (hereinafter called hot gases) to flow from the upper part of.
such a furnace through a suitably arranged pipe or flue and to re-enter the lower
portion of the furnace.
L
In a bot blast furnace constructed according to this invention the vertical pipe or
flue used for conducting the hot gases downward is arranged to communicate at its
upper end with the upper part of the furnace either directly or through a chamber.
that communicates with the furnace by one or more openings or ports. The lower
end of the pipe or flue is in communication with a box casing or chamber that com-
municates with the lower part of the furnace and through which passes the air tuyere
When the top of the furnace is open or
or tuyeres used for supplying air thereto.
only partially closed, the exit opening or port (or each if there be more than one) for
When the furnace is closed at the
hot gases is arranged below the top of the fuel.
top and the whole of the hot gases are drawn off, the opening or port, or openings or
ports, can be situated above the fuel. In this case the lower part of the furnace is
provided with one or more exit openings or ports through which hot gases after being.
completely burnt can escape and be thence led either to a chimney or to a heating
device such as a blast heater wherein the heat of the gases may be utilized.
In cases where a blast furnace is provided with a downtake for conducting the hot
gases to a hot blast stove, a branch pipe is according to this invention provided for
conducting a portion of the hot gases from such downtake to the casing or chamber
through which the air tuyeres pass.
In some cases the flue for hot gases as well as the lower chamber into which they
are discharged before re-entering the furnace may be formed in the furnace wall.
In another form of furnace according to this invention the outlets for hot gases are
arranged near the throat or contracted part of the furnace.
By my invention a quantity of hot gases will be caused to continuously circulate
through the furnace.
Dated this 16th day of October 1889.
'
1.

page_text: COMPLETE SPECIFICATION.
Improvements in Furnaces, such as Cupola and Blast Furnaces.
I, FRANCIS EDWARD Ross, of No. 10 Whitehorse Road, Croydou, in the County
of Surrey, Civil Engineer, 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 :-
This invention relates to improvements in furnaces of the kind in which a con-
siderable height or mass of fuel mixed with metal or ore, is maintained upon the
furnace hearth, as for examples, cupola and blast furnaces. The hot gases and products
of combustion that escape. from. the upper part of such furnaces usually contain a
large proportion of combustible gas, consisting mainly of carbonic oxide produced by
the carbonic acid gas resulting from the combustion of fuel in the combustion zone of
the furnace, combining with an additional quantity of carbon in passing through the
superincumbent mass of heated fuel; and the object of this invention is to utilize in
a continuous manner for heating purposes, the carbon contained in a portion of the:
carbonic acid so produced, by causing the same after it has been converted into
carbonic oxide in the manner described, to be withdrawn, with the other gases present,
from the upper part of the furnace. and to re-enter the furnace at the lower part.
thereof where it is again burnt and converted into carbonic acid, which is again con-
verted into carbonic oxide for re-use as before. Thus heat is produced for melting or,
other purpose by the complete combustion of a quantity of carbon, which is practically,
caused to continuously circulate through the furnace, and is used over and over again
in conjunction with other carbon, which, after complete combustion, is allowed to
escape from the furnace as carbonic acid. By this means furnaces of the kind.
mentioned can be worked in a more economical manner than usual.
The jets of air usually blown into the lower portions of furnaces. of the kind.
mentioned, may advantageously be utilized to induce a portion of the gases containing
carbonic acid to flow through the mass of fuel and after conversion of. the carbonic
acid into carbonic oxide, to flow from the upper part of the furnace through a suitably,
arranged pipe or flue and to re-enter the lower portion of the furnace.
In a hot blast furnace or a cupola constructed according to this invention, a vertical
pipe or flue used for conducting the hot gases downward, is arranged to communicate
at its upper end with the upper part of the furnace, either directly or through a
chamber that communicates with the furnace by one or more openings or ports. The
lower end of this pipe or flue is in communication with a box, casing, or chamber,
that communicates with the lower part of the furnace, and through which passes the
air tuyere (or tuyeres) used for supplying air thereto. The furnace is closed at the top
and the hot gases drawn upward through the mass of fuel therein by the inductive action
of the air tuyere or tuyeres, are drawn off through an opening or port, or openings or
ports situated near the top of the furnace. The lower part of the furnace is provided
with one or more exit openings or ports through which that portion of the hot gases
and products of complete combustion which is not drawn through the mass of fuel,
can escape, and be thence led either to a chimney, or to a heating device such as a
blast heater, wherein the heat of the gases may be utilized.
In cases where the furnace is already provided with a downtake for conducting the
waste gases to a hot blast stove, a branch pipe is, according to this invention, provided
for conducting a portion of the waste gases from such downtake to the casing or
chamber. through which the air tuyeres pass, for the purpose and in the manner
herein before described.
In some cases the flue for hot gases, as well as the lower chamber into which they
are discharged before re-entering the furnace, may be formed in the furnace.wall.
In the accompanying drawings,
Fig. 1 is a vertical section, partly in elevation; and
Fig. 2 is a plan, partly in section, of a cupola furnace according to this invention.
175

page_text: 1 is the shaft of the furnace normally closed at its top by a cup and cone arrange-
ment of ordinary construction as shown and in communication at its lower end with
an enlarged combustion or melting chamber 2 above which it is centrally arranged.
3 is an air tuyere for introducing into the combustion chamber, air supplied by a
pipe 3 and which may have been heated by passing through a pipe or conduit 4
located within a stove or heater 5. 6 is a box or casing formed with an opening at 6ª
that forms a continuation of an inclined opening 7 through which air is injected into
the combustion chamber through the air tuyere and by which the interior of the box
or casing communicates with the combustion chamber. The interior of the box or
easing 6 is also in communication, by a pipe 8, and valve chest 8' with an annular
chamber 9 that is in communication by openings 10, with the interior of the upper
part of the shaft of the furnace. 8b is a valve for controlling the passage of gases
through the pipe 8. The air tuyere is arranged to project into the box or casing 6
and is arranged in relation to the openings 6 and 7 as shown, so that air under
pressure passing through the air tuyere will induce hot gases, containing carbonic
acid to pass from the combustion chamber 2 upward through the mass of heated fuel
in the shaft, 1 where the carbonic acid will be converted into carbonic oxide, and then
to pass through the openings 10, chamber 9 and pipe 8 to the box or casing 6 whence
they are discharged with the air from the tuyere, through the opening 7 into the
combustion chamber so that the carbonic oxide present in them will be completely
burnt and reconverted into carbonic acid which is again drawn through the fuel and
re-used as before. Thus whilst the furnace is in operation a portion of the gases
produced, containing a definite quantity of carbon, will be caused to circulate through
the furnace in a continuous manner for the purpose hereinbefore mentioned. 11 is
an opening for the escape of the hot gases and products of combustion that are not
induced to flow through the shaft of the furnace. This opening is placed in communi-
cation by a flue 12 with the stove or heater 5, or it may communicate with a chimney
direct as may be desired. 12ª is a damper for controlling the passage of gases through
the flue 12.
13 is a poking hole fitted with a tube 14 carrying a hinged or pivoted cover 15.
This tube and cover are shown separately in Fig. 3. Through the hole 13 a bar can
be introduced from time to time to ensure the regular descent of the charge in the
furnace shaft 1. The outer end of the air tuyere may be provided with a glazed
peephole at 16.
In carrying out my invention I find it necessary, to obtain good results, to keep
the top of the furnace normally closed.
Fig. 4 is a central section; and Fig. 5 a sectional plan of a modified construction
of cupola furnace according to which the combustion chamber 2 communicates at
one end with the shaft 1, and the air blast is introduced at the opposite end
through a vertical opening 7. 16 is the peephole normally closed by a brick ;
and 17 is the tap hole. The operation of this furnace is similar to that shown in
Figs. 1 and 2.
As will be obvious a pump may be used for withdrawing the hot gases from the
top of the furnace and introducing them into the lower portion thereof, but I prefer
the arrangement described and shown.
For melting metal in cupolas as ordinarily constructed and worked it is necessary
to use coke as fuel but by constructing and working cupolas in the manner herein
described, coal can be used as it will be converted into coke before it reaches the
combustion or melting chamber. The combustible gases and vapours driven off
during the coking operation, are drawn off with the hot gases withdrawn from the
combustion chamber, and introduced with these gases into the combustion chamber
by the inducing action of the air from the air tuyere, and are thus utilized.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The combination with a furnace of the kind bereinabove referred to, having a

page_text: closed top, upper and lower outlet openings for hot gases and products of combustion,
and a lower inlet opening or openings for air, and for bot gases, of means for
causing a portion of the hot gases and products of combustion to pass from the
combustion chamber or .zone of the furnace through the mass of fuel and afterwards
to re-enter the combustion chamber or zone substantially in the manner and for
the purpose herein set forth.
2. My improved furnaces with means for causing circulation of hot gases and
products of combustion, constructed arranged and operating substantially as herein-
before described with reference respectively to and shewn in Figs. 1 and 2 and in.
Figs. 4 and 5 of the drawings annexed for the purpose specified..
Dated this 14th day of July 1890.
F. E. ROSS..
W. Lloyd Wise,
46, Lincoln's Inn Fields, London, W.C., Applicant's Agent..