IMPROVEMENTS IN CUPOLA FURNACES, AND IN THE PROCESSES OF SMELTING PIG METAL AND WROUGHT IRON BY MEANS OF SUCH FURNACES
Year: 1879

page_text: LETTERS PATENT to Gerard Wenzeslaus von Nawrocki, of the Firm of
J. Brandt and G. W. von Nawrocki, Patent Agents, of No. 124, Leipziger-
strasse, Berlin, in the German Empire, for the Invention of "IMPROVEMENTS
IN CUPOLA FURNACES, AND IN THE PROCESSES OF SMELTING PIG METAL AND
WROUGHT IRON BY MEANS OF SUCH FURNACES." A communication by Gustav.
Ibrügger of Norden. Ostfriesland, in the German Empire.
PROVISIONAL SPECIFICATION left by the said Gerard Wenzeslaus von
Nawrocki at the Office of the Commissioners of Patents on the 12th
September 1879.
GERARD WENZESLAUS VON NAWROCKI, of the Firm of J. Brandt and G. W von
Nawrocki, Patent Agents, of No. 124, Leipzigerstrasse, Berlin, in the German
Empire. "IMPROVEMENTS IN CUPOLA FURNACES, AND IN THE PROCESSES OF
SMELTING PIG METAL AND WROUGHT IRON BY MEANS OF SUCH FURNACES." [A
communication by Gustav Ibrügger, of Norden, Ostfriesland, in the German
Empire.]
The present Invention has mainly for its object an improved method of smelting
together pig metal and wrought iron in a cupola furnace, whereby instead of
introducing the wrought iron into the pig metal after this has been fused in the
cupola as is at present effected, the wrought iron is first heated to melting point in
a special chamber below the actual cupola chamber, from which the melted pig
metal is then caused to flow down into such lower chamber to become intimately
mixed with the liquid wrought iron.
For this purpose the cupola furnace has below its ordinary melting chamber a
second chamber with which it communicates by a channel or opening in its bottom
surface, and which is by preference of oblong form, so as conveniently to receive
bars of wrought iron, the cupola chamber being itself also by preference made of
oblong form.
The lower chamber has firstly a charging opening through which the wrought
iron is introduced, and secondly, a tapping hole towards which the bed of the
chamber slopes downwards, while at the opposite side at a higher level is provided
a hole for drawing off the liquid slag. This side of the chamber is by preference

page_text: made entirely removeable, so as to give access readily to the interior for repairs.
In operating with this furnace the wrought iron is first charged together with some
charcoal into the lower chamber, and fuel being introduced and ignited in the
cupola chamber, the gaseous products of combustion are caused to descend through
the communicating passage into the lower chamber, where the combustible particles
thereof enter into combustion with a blast of air introduced through a pipe. By.
this means the chamber becomes highly heated so that the wrought iron is fused;
the pig metal is then introduced into the cupola chamber together with fuel, and the
top aperture of the cupola being more or less closed, the gaseous products of com-
bustion continue to pass down into the lower chamber, so as to maintain this at a
high heat while the melted pig metal- is flowing down and mixing with the liquid
wrought iron, which by the shallow extended form of the chamber is spread out in
a comparatively thin layer, so that the cast iron mixes therewith very rapidly and
uniformly. On completion of the smelting the liquid compound metal is run off
through the tapping hole. In employing this furnace for smelting pig metal only,
the lower chamber is heated by the combustion of the gases descending from the
cupola chamber in the same manner as above described, so that the pig metal as it
melts and flows down into it is there maintained in a highly heated liquid
condition until it is run off. The cupola chamber has two rows of tuyeres or blast
holes, the inner orifices of which are made of a narrow vertical oblong shape,
whereby they are prevented from becoming choked with slag. The before
described lower chamber of the furnace may either be built in one therewith,
or it may be separate therefrom and mounted on wheels so as to be withdrawn
when required.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Gerard Wenzeslaus von Nawrocki in the Great Seal Patent Office on
the 11th March 1880.
GERARD WENZESLAUS VON NAWROCKI, of the Firm of J. Brandt and G. W. von;
Nawrocki, Patent Agents, of No. 124, Leipzigerstrasse, Berlin, in the German
Empire. "IMPROVEMENTS IN CUPOLA FURNACES, AND IN THE PROCESSES OF
SMELTING PIG METAL AND WROUGHT IRON BY MEANS OF SUCH FURNACES." A
communication by Gustav Ibrügger, of Norden, Ostfriesland, in the German
Empire.
The present Invention has mainly for its object an improved method of smelting
together pig metal and wrought iron in a cupola furnace, whereby instead of
introducing the wrought iron into the pig metal after this has been fused in the
cupola as is at present effected, the wrought iron is first heated to melting point in
a special chamber below the actual cupola chamber, from which the melted pig
metal is then caused to flow down into such lower chamber to become intimately

page_text: mixed with the liquid wrought iron. For this purpose the cupola furnace has
below its ordinary melting chamber a second chamber, with which it communicates.
by a channel or opening in its bottom surface, and which is by preference of oblong
form, so as conveniently to receive bars of wrought iron, the cupola chamber being.
itself also by preference made of oblong form. The lower chamber has firstly a
charging opening through which the wrought iron is introduced; and secondly, a
tapping hole towards which the bed of the chamber slopes downwards, while at
the opposite side at a higher level is provided a hole for drawing off the liquid
slag. This side of the chamber is by preference made entirely removeable, so as
to give access readily to the interior for repairs. In operating with this furnace
the wrought iron is first charged together with some charcoal into the lower
chamber, and fuel being introduced and ignited in the cupola chamber, the gaseous
products of combustion are caused to descend through the communicating passage
into the lower chamber, where the combustible particles thereof enter into com-
bustion with a blast of air introduced through a pipe. By. this means the chamber.
becomes highly heated so that the wrought iron is fused; the pig metal is then
introduced into the cupola chamber together with fuel, and the top aperture of
the cupola being more or less closed, the gaseous products of combustion continue
to pass down into the lower chamber, so as to maintain this at a high heat,
while the melted pig metal is flowing down and mixing with the liquid wrought
iron, which by the shallow extended form of the chamber is spread out in a
comparatively thin layer, so that the cast iron mixes therewith very rapidly and
uniformly. On completion of the smelting the liquid compound metal is run off
through the tapping hole. In employing this furnace for smelting pig metal only,
the lower chamber is heated by the combustion of the gases descending from the
cupola chamber in the same manner as above described, so that the pig metal as it.
melts and flows down into it is there maintained in a highly heated liquid condition
until it is run off. The cupola chamber has two rows of tuyeres or blast holes, the
inner orifices of which are made of a narrow vertical oblong shape, whereby they.
are prevented from becoming choked with slag.
The before described lower chamber of the furnace may either be built in one
therewith, or it may be separate therefrom and mounted on wheels so as to be
withdrawn when required.
1
Fig. 1 of the accompanying Drawing shews a longitudinal section of a cupola
furnace constructed according to the present Invention; Fig. 2 shews an elevation;
and Fig. 3, a sectional plan on line x, x, Fig. 2. The smelting chamber A may be
of any suitable form and construction, but the form shewn in Fig. 3 is preferred as
being more suitable for the introduction of larger bars, and for a more uniform
distribution of the blast. The shaft is provided with two tiers of tuyeres or blast
orifices, which are by preference of elongated form as shewn, this form having the
advantage that they do not so readily become choked with slag. Below the
chamber A is the collecting chamber B, the floor of which slopes down to
the tapping hole a, while the back wall b of the chamber is provided with an
opening for drawing off the slag, and is entirely removeable for gaining access to
the interior for repairs. The roof of the chamber B is arched, and communicates
with the smelting chamber by means of a small opening d of any desired section.
Somewhat above the bottom of the smelting chamber is provided the discharging
hole f. The chamber B has in front, above the tapping hole, an aperture g, which
can also be arranged in a sloping position, and be provided with a sliding door, and
which serves for introducing the wrought iron and charcoal, and for observing and
stirring the metal. The chamber B also has a blast pipe leading from the main
blast pipe D. In operating with this furnace wood is in the first instance placed
on the bed of the chamber A, and upon this some coke, and the furnace is then
charged as an ordinary cupola furnace. As soon as the blast is admitted the gases
pass through the openings d into the chamber B, and heat this to such an extent
that the metal is not cooled afterwards, which is an advantage over ordinary cupola
furnaces without collecting chambers, in which the liquid metal has itself to effect

page_text: the heating of the hearth. The combustible gases passing with the products of
combustion into the chamber B are burnt by means of the blast h. If wrought
iron is to be smelted with the pig metal, the former in the form of scrap and the
like is first introduced into the chamber B together with a small quantity of
charcoal. The chamber A is then filled as above described, and the charge ignited,
and on admission of the blast the top of the furnace is closed so as to cause the
gases to pass through the openings d into the chamber B, where they are burnt.
An intense heat is thus produced in this chamber so as to melt the wrought iron.
This being completed, the chamber A is provided with its remaining charge of coke
and with pig metal, during the smelting of which the gases continuing to pass into
the chamber B heat the melted wrought iron to such a degree, that it readily and
intimately mixes with the melted pig metal, as this runs down through the
opening d into the extended surface of the bath of wrought iron. The charge of
pig metal having all been melted and mixed with the wrought iron, the mass is
stirred up and tapped off. If the operation is to be repeated, the slag is first drawn
off and fresh wrought iron placed in the chamber B, and the operation repeated, as
above described. This process may also be carried on in other constructions of
cupola furnaces with collecting chambers. It is to be observed that the collecting
chamber may be made to suit any section of furnace, its size being regulated by
the capacity of the furnace, and the proportion of wrought iron to be added; the
capacity of the chamber B can be reduced by moving the back wall further inwards
towards the opening d. It may also be made removeable from the furnace, as
before described.
<
Having thus described the nature of this Invention, and in what manner
the same is to be performed, as .communicated to me by my correspondent, I
claim,―
First. The use in combination with cupola furnaces of a separate collecting
chamber immediately below the smelting chamber, and communicating with the
latter by an opening in its floor, substantially as and for the purposes herein
described.
1
Second. The method of smelting wrought iron together with pig metal in cupola
furnaces by fusing the wrought iron in a separate chamber, so as to present an
extended surface of liquid metal into which the melted pig metal runs from the
smelting chamber, whereby the two metals are effectually combined without
affecting the degree of liquidity of the product, substantially as herein described.
In witness whereof, I, the said Gerard Wenzeslaus von Nawrocki, have here-
unto set my hand and seal, this Eighth day of March, in the year of our
Lord One thousand eight hundred and eighty.
GERARD WENZESLAUS V NAWROCKL
(LS)
+
GERARD WENZESLAUS V. NAWROCKI. (L.S.)