Improvements in the Manufacture of Iron and Steel, and in Furnaces for that purpose.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Iron and Steel, and in Furnaces
for that purpose.
I, DIMITRIS TSCHERNOFF, Engineer, of Pessotschnaya, 25, St. Petersburg,
Russia, do hereby declare the nature of this invention to be as follows:-
:―
It is well known that numerous trials have been made to employ in blast
furnaces combustible gases in place of expensive solid fuel (charcoal, coke, etc.),
and to control the action of blast furnaces in such a manner that in the tower
hearth, cast-iron, iron or steel may be obtained, but till now these trials have
never given satisfactory results.
The object of my invention is to construct a blast furnace attaining both these
purposes. This furnace differs from ordinary furnaces, in that the current or
flow of gas, which is generally single, is in my blast furnace divided into two
separate flows:-
1. The reducing flow, which is let in the furnace at the height of the cemen-
tation-zone of an ordinary blast furnace; this flow of incandescent gas is led
vertically from below to the top through the upper shaft of the furnace and
serves to reduce the ore; and-
2. The melting flow, which is led from a generator to the hearth of the blast
furnace together with air for combustion; this gas being ignited melts the
reduced metal and slag, which both move down in the shaft, and is directed
horizontally through a side-port, and flows through a covered front hearth to an
exhaust chimney.
The shaft of the furnace is continually supplied with ore and flux, to which
small quantities of charcoal or coke may be admixed or not. At a zone, corre-
sponding to the cementation zone of ordinary blast furnaces, ports or holes are
arranged, through which the incandescent gas arrives from the generator at a
temperature about 1000 to 1200° Celsius; this gas passes through the ore (which
becomes incandescent), reduces the metal and flows toward ports in a central gas
exhaust conduit. The reduced ore with the flux drops to the hearth and is
melted by the combustion of the gas admitted through ports, while air is let
through other ports arranged preferably in checkered rows; the flames of the gas
surround the ore column and are drawn through ports into a covered front
hearth which communicates with the main chimney. The front hearth is a kind
of gas regenerating furnace with this particularity, that it receives the flames
from the central hearth by a side port; all the gases exhausted by the common
main chimney. Moreover the reduced metal and slag flows directly through the
same port into the hearth. The slag is removed through a port and flows by a

page_text: channel into a trolly. The metal is treated on the bottom of the hearth in a
similar manner to the Martin process, that is to say, the metal is stirred and
mixed with spiegel iron, ferro-manganese, ferro-silicium or other similar matters
in a proportion according to the nature and destination of the metal. As soon as
sufficient metal is formed, it is removed through a tap hole and cast in ordinary
way. Thus my blast furnace can work without interruption as long as it does
not require any structural repairs. The walls of the furnace are provided with
sight holes for watching the process and to assist the moving down of the charge.
The controlling of the reduction of the metal and of the degree of its carbura-
tion is obtained partly by admixture to the charge of a required quantity of
carbonic matter (charcoal, coke, anthracite, resin, etc.), and partly by the greater
or less intensity of the firing in the lower central hearth in combination with
the temperature and the volume of reducing gas injected into the furnace. Thus
for obtaining cast iron, about 5% of charcoal or coke (by weight) must be added
to the charge of ore, and the temperature of the injected gas must be raised and
its volume must be greater. For obtaining wrought iron, 'the admixture of
coal can be dispensed with, and the temperaturd of the reducing gas must he
lowered, but the temperature in the lower central hearth must be raised; in this
manner the reduction and carburation are retarded, and the melting, and conse-
quently the moving down of the charge are hastened. For obtaining steel, more
or less soft, intermediate measures must be taken.
Certain construction features of this furnace also present improvements dis-
tinguishing it from ordinary apparatus of this kind.
I. The gas, obtained from solid or liquid fuel by means of a blast generator,
before it is supplied to the ports must be preferably heated to a temperature of
about 1000 to 1200° Celsius. For this purpose this gas is let through a brick-
work heating apparatus placed as nearly as possible to the blast furnace. The
gas generators are for this purpose arranged directly on the walls of the furnace
between the standards supporting the brickwork of the shaft, and of the boshes
of the blast furnace. It is preferable to provide relieving arches in the brick-
work above the places where the generators are placed to permit of easy repair
of the brickwork without disturbing the main masonry of the blast furnace.
The working of the generators presents this feature, distinguishing them from
ordinary generators, that the products of distillation and the wet vapours, which
are developed by the fuel, are exhausted separately from the combustible gases,
which are consequently more rich in carbonic oxide, more poor in nitrogen and
much more dry and hot than the gases of ordinary generators.
II. As the reduction of the metal from its oxide by means of the carbonic
oxide is performed without expense of heat, the quantity of heat, brought to the
furnace by the incandescent gases, will be expended only in heating the ore and
flux consequently the gases, arriving to the furnace from the generator at a
temperature about 1000 to 1200° C., will have on entering the chimney or con-
duit at lease a temperature of 800° C. This circumstance allows these gases to
be regenerated by placing in the conduit a certain quantity of coal loaded through
a hopper at the upper part of the conduit. The regenerated gas after having
passed through a dry dust catching apparatus, can be advantageously used, par-
ticularly after being previously heated for melting the reduced metal and slag
in the central hearth and front hearth. In case the combustion temperature
should be too low for melting iron, a certain bulk of acetylene may be added to
the gas.
III. For melting the reduced metal and the cinders, liquid fuel may be used
advantageously for this purpose a liquid fuel (for instance naphtha) and hot
air may be injected through the ports by means of jet burners.
Dated this 10th day of February 1898
CARPMAEL & Co.,
Agents for the Applicant,

page_text: Improvements in the Manufacture of Iron and Steel, and in Furnaces
for that purpose.
I, DIMITRIS TSCHERNOFF, Engineer, of Pessotschnaya 25, St. Petersburg,
Russia, 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:-
―
It is well known that numerous trials have been made to employ in blast
furnaces combustible gases in place of expensive solid fuel (charcoal, coke, etc.),
and to control the action of blast furnaces in such a manner that in the tower
hearth, cast-iron, iron or steel may be obtained, but till now these trials have
never given satisfactory results.
The object of my invention is to construct a blast furnace attaining both these
purposes. This furnace differs from ordinary furnaces, in that the current or
flow of gas, which is generally single, is in my blast furnace divided into two
separate flows:-
1. The reducing flow, which is let in the furnace at the height of the cemen-
tation-zone of an ordinary blast furnace; this flow of incandescent gas is led
vertically from below to the top through the upper shaft of the furnace and
serves to reduce the ore; and
2. The melting-flow, which is led from a generator to the hearth of the blast
furnace together with air for combustion; this gas being ignited melts the
reduced metal and slag, which both move down in the shaft, and is directed
horizontally through a side port, and flows through a covered front hearth to an
exhaust chimney.
Figure 1 is a vertical section of a blast furnace constructed according to this
invention. Figure 2 is a vertical section on the line 2, 2, Figure 1 of the regenera-
tive gas furnace E. Figure 3 is a part vertical section (on the line 3, 3, Figure 1)
and part elevation and Figure 4 is a part elevation showing the ports a.
The shaft A of the furnace is continually supplied with ore and flux, to which
small quantities of charcoal or coke may be admixed or not. At a zone B corre-
sponding to the cementation zone of ordinary blast furnaces, ports or holes aa
are arranged, through which the incandescent gas arrives from the generator at
a temperature about 1000 to 1200° Celsius; this gas passes through the ore (which
becomes incandescent), reduces the metal and flows toward ports in a central
gas exhaust conduit C. The reduced ore with the flux drops to the hearth D and
is melted by the combustion of the gas admitted through ports d while air is let
through other ports arranged preferably in checkered rows; the flames of the
gas surround the ore column F and are drawn through ports e into a covered front
hearth E which communicates with the main chimney. The front hearth is a
kind of gas regenerating furnace with this particularity, that it receives the flames
from the central hearth D by a side port e, all the gases exhausted by the common
main chimney. Moreover the reduced metal and slag flows directly through the
same port e into the hearth E. The slag is removed through a port f and flows by
a channel into a trolley. The metal is treated on the bottom of the hearth E in
a similar manner to the Martin process, that is to say, the metal is stirred and
mixed with spiegel-iron, ferro-manganese, ferro-silicium or other similar matters
in a proportion according to the nature and destination of the metal. As soon
as sufficient metal is formed, it is removed through a tap hole g and cast in
ordinary way. Thus my blast furnace can work without interruption as long as
it does not require any structural repairs. The front hearth E can in some cases
be arranged at a certain distance from the central hearth D, in which case the side

page_text: port a will be replaced by an elongated conduit connecting both hearths. The
walls of the furnace are provided with sight holes s for watching the process and
to assist the moving down of the charge. Should the action of the furnace become
disturbed, the sight holes s, s can be used for introducing into the furnace various
substances in order to liquify the slags, such as silicates of alkalis, fluorspar and
the like. The controlling of the reduction of the metal and of the degree of its
carburation is obtained partly by admixture to the charge of a required quantity
of carbonic matter (charcoal, coke, anthracite, resin, ite.), and partly by the greater
or less intensity of the firing in the lower central hearth in combination with the
temperature and the volume of reducing gas injected into the furnace through the
ports a. Thus for obtaining cast iron, about 5% of charcoal or coke (by weight)
must be added to the charge of ore, and the temperature of the injected gas must
be raised and its volume must be greater. For obtaining wrought iron, the ad-
mixture of coal can be dispensed with, and the temperature of the reducing gas
must be lowered, but the temperature in the lower central hearth must be raised;
in this manner the reduction and carburation are retarded, and the melting, and
consequently the moving down of the charge are hastened. For obtaining steel,
more or less soft, intermediate measures must be taken.
Certain construction features of this furnace also present improvements dis-
tinguishing it from ordinary apparatus of this kind.
I. The gas, obtained from solid or liquid fuel by means of a blast generator,
before it is supplied to the ports a must be preferably heated to a temperature of
about 1000 to 1200° Celsius. For this purpose this gas is let through a brickwork
heating apparatus, placed as nearly as possible to the blast furnace as shown in
Figure 3. The gas generators N are for this purpose arranged directly on the
walls of the furnace between the standards supporting the brickwork of the shaft,
and of the boshes of the blast furnace. It is preferable to provide relieving arches
in the brickwork above the places where the generators are placed as shown in
Figure 4 to permit of easy repair of the brickwork of the wall L without disturb-
ing the main masonry M of the blast furnace.
The working of the generators N prevents this feature, distinguishing them
from ordinary generators, that the products of distillation and the wet vapours,
which are developed by the fuel, are exhausted separately from the combustible
gases, which are consequently more rich in carbonic oxide, more poor in nitrogen
and much more dry and hot than the gases of ordinary generators..
In Figure 30 is an air pipe, provided with a controlling valve t; this pipe leads
air from the blowing apparatus to an air chamber (as usual) and from this to the
generator N through the ports n, n. Here the air penetrates the bed of incan-
descent fuel; the carbonic oxide produced, with a part of nitrogen, passes through
the ports a, a to the hearth D of the blast furnace, and the products of distillation
and also the wet vapours, produced by the fuel, which is loaded through the
hopper m, ascends the pipe P and passes through the branch pipes p, to the upper
part of the blast furnace; here the gases traverse the upper beds of fuel, that is
to say the parts recently loaded, and after having transmitted to them their heat
are exhausted, as products almost without value, through the mouth of the
furnace, or are withdrawn in order that the gases may not incommode the work-
men. The pipe P can be made of brickwork, in order to prevent the cooling of
the gases.
The bulk of the products of combustion, exhausted from the generator,
can be controlled by means of valves, on the branch pipes p, p.
II. As the reduction of the metal from its oxide by means of the carbonic
oxide is performed without expense of heat, the quantity of heat, brought to the
furnace by the incandescent gases, will be expended only in heating the ore and
flux; consequently the gases, arriving to the furnace from the generator at a
temperature about 1000 to 1200° C., will have on entering the chimney or con-
duit C at least a temperature of 800° C. This circumstance allows these gases to
be regenerated by placing in the conduit C a certain quantity of coal k (Figure 3)
loaded through a hopper H at the upper part of the conduit; certain excess of

page_text: this coal will go out through the lower aperture of the conduit C with the ashes
and will follow the column of ore as it moves down to the lower hearth D. The
regenerated gas after having passed through a dry dust catching apparatus, can be
advantageously used, particularly after being previously heated for melting the
reduced metal and slag in the central hearth 1) and front hearth E. In case the
combustion temperature should be too low for melting iron, a certain bulk of acety-
leno may be added to the gas.
The generators NN can be also arranged at some distance from the walls of the
blast furnace; in this case the gas will be supplied to the ports or openings a, a
by conduits, which may be iron pipes with a refractory lining.
III. For melting the reduced metal and the cinders, liquid fuel may be used
advantageously; for this purpose a liquid fuel (for instance naphtha) and hot air
may be injected through the ports d¹ by means of jet burners.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. The use of a separate current or flow of incandescent gas, into the shaft of the
furnace in order to reduce the ore, and of another current or flow of gas mixed
with hot air and acting in the hearth of the furnace in order to melt the metal
and the cinders or slags.
2. The special means for controlling the composition of the products of the
furnace by controlling at will the reciprocal quantitative and qualitative correla-
tions of the two currents or flows of gas, referred to in the preceding claim.
3. The arrangement of the covered front gas regenerating hearth for the final
treatment of the metal before its removal from the furnace.
4. The blowing gas generators arranged directly on the walls of the furnace
and having means for separating the products of the distillation and the wet
vapours of the fuel from the generator gases properly speaking, by means of special
conduit pipes, arranged directly above the fuel freshly loaded into the generator.
5. The regeneration of the return gases by means of coal, charged in a central
gas exhaust conduit.
6. The manufacture of iron and steel and furnaces for that purpose substan-
tially as described and illustrated in the drawings.
Dated th: 01.1 1
1000
CARPMAEL & Co.,
Agents for the Applicant.