IMPROVEMENTS IN CUPOLA FURNACES
Year: 1876

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS
IN CUPOLA FURNACES." A communication from abroad by the Firm of J. J.
Heurtier Carré and Company, of Paris, France.
Sealed the 8th May 1877, and dated the 10th November 1876.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 10th November 1876.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN CUPOLA FURNACES."
This Invention relates to improvements in cupola furnaces, and is illustrated in
the accompanying Drawings, in which Figure 1 represents a vertical section of the
furnace on the line A, B, C, Figure 3, passing through the axis of one of the upper
tuyeres; Figure 2, a vertical section on line D, E, Figure 3, passing through one of
the lower tuyeres and one of the hydrocarbon reservoirs; Figure 3, horizontal
section on line F, G, H, I, Figure 4; Figure 4, front elevation of the cupola.
The cupola, composed of the brickwork b, enveloped in an iron casing a, is sur-
rounded by a blast chamber f constructed of plate iron, in which the blast arrives
by a pipe branching from the blast main from the blowing engine, and whence it is.
distributed in the furnace by tuyeres ginclined downwards, placed at equal distances
apart around the circumference, and embedded in the brickwork forming the interior
lining of the furnace. The number and dimensions of the tuyeres vary according
to the quantity of metal to be melted. The blast chamber is provided with sight
holes h opposite the several tuyeres, each closed by a sliding door fitted with a blue
glass, through which when closed the progress of the operation may be watched,
and when opened the tuyeres cleared.
At a certain distance above the row of tuyeres there is another row of smaller
size l, also inclined downwards, and communicating with the blast chamber by
means of tubes furnished with stop-cocks i; l, sight holes closed by doors fitted
with blue glass, and sliding in grooves cast on the tubes j; they answer the the
same purpose as those h. Number of tuyeres l in this upper row is also variable, and
depends on that of the lower row g, the numbers in the two rows being always
equal. The size of the upper tuyeres should be between one-fourth and one-third
that of the lower tuyeres g; these limits should not be exceeded, because if on the

page_text: one hand they are greater than one-third the quality of the metal is affected, and
on the other hand if less these upper tuyeres, which simply act as regenerators for
the gases, obliging them to burn within well defined limits, will cease to have any
useful effect, and the gases, imperfectly utilized, will cause an increased expenditure
of fuel. This mechanical arrangement for regulating the distribution of the blast
enables the workman to govern the operation in the most complete and methodical
manner.
The various advantages obtained by this Invention are as follows:--
1st. In all cupolas having several rows of tuyeres the iron first melted does not
run hot enough, and many founders producing articles which require the metal very
hot at the beginning of the operation have been forced to abandon the use of such
cupolas, as they were obliged to run the metal into pigs instead of into the moulds.
This want of heat is due solely to the fact that owing to the position of the upper
row of tuyeres the gases are free to ascend rapidly before the lower tuyeres have
had time to heat the melting chamber of the cupola, which abstracts the heat from
the iron first melted, and until this part of the cupola is sufficiently heated the iron
continues to be thus cooled. With the mechanical arrangement of this Invention
it is only necessary in order to have the iron hot enough from the beginning to
shut the stop-cock i, so that the blast being on through the lower tuyeres only
the melting chamber will be heated because these tuyeres are in proximity to the
hearth; the commencement of the melting will thus be retarded, and the metal when
melted meets with a higher temperature in the melting chamber than its own, and
hence instead of being cooled the metal is from the commencement fit for the most
difficult casting.
2nd. The obstruction of a tuyere is immediately remedied by shutting off the
blast through that tuyere. Such obstructions are due either to the charge or
to the quality of coke used, and when they occur occasion much trouble in order to
clear the tuyere and restore the proper working of the furnace; but with this
Invention it is only necessary, as before mentioned, to shut off the blast through
that particular tuyere by means of the stop-cock, whereupon the metal being no
longer cooled by the blast is heated to melting point, and the obstruction thus dis-
appears in a few minutes, after which the blast may be again turned on, and the
normal working of the furnace restored.
3rd. At the end of the operation the difficulty is to melt the metal of the last
charge without leaving any unmelted, and for this purpose it is necessary to shut off
the blast from the upper tuyeres as soon as the charge descends to about three
feet above the tuyeres, so that the metal which might otherwise be cooled by
the blast of the upper row of tuyeres runs down into the melting chamber raised to
a high temperature by the lower tuyeres.
The Invention further comprises a special arrangement for the employment of
liquid hydrocarbons for melting large blocks of cast iron; it consists of two reser-
voirs m, m, located above the blast chamber, and connected at their lower part with
two diametrically opposite lower tuyeres g by pipes provided with stop-cocks for
conveying the hydrocarbons to these tuyeres. At the upper part of each reservoir
two short pipes or mouths are provided, of which one o, through which the
reservoir is filled, is closed by a plug or cover secured by a cross bar, whilst the is
continued up by a tube p opening into the interior of the shaft in order to admit
the pressure therein to the surface of the liquid in the reservoir m to balance that
coming through the tube n below. A sliding valve at the base of the pipe p cuts
off the communication with the reservoir. When it is desired to use the hydrocarbon
as fuel the valve is opened, and also the cock beneath. The liquid then descends
by its own gravity to the tuyere, where it is taken by the blast and conveyed into
the interior of the furnace. In contact with the coke and melted metal it ignites,
producing great heat, which assists the melting. As in ordinary cupolas there is a
door c at bottom at which the metal is tapped, and at a suitable height there is a
clearing hole.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the 9th
May 1877.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Mid-
dlesex, Patent Agent. "IMPROVEMENTS IN CUPOLA FURNACES." A communication
from abroad by the Firm of J. J. Heurtier Carré and Company, of Paris, France.
This Invention relates to improvements in cupola furnaces, and is illustrated
in the accompanying Drawings, in which Figure i represents a vertical section of
the furnace on line A, B, C, Figure 3, passing through the axis of one of the upper
tuyerės; Figure 2, a vertical section on line D, E, Figure 3, passing through one of
the lower tuyeres and one of the hydrocarbon reservoirs; Figure 3, a horizontal
section on line F, G, H, I, Figure 4; Figure 4, a front elevation of the cupola.
The cupola, composed of the brickwork b, enveloped in an iron casing a, is sur-
rounded by a blast chamber f constructed of plate iron, in which the blast arrives
by a pipe branching from the blast main from the blowing engine, and whence it is
distributed in the furnace by tuyeres ginclined downwards placed at equal distances
apart around the circumference embedded in the brickwork forming the interior
lining of the furnace. The number and dimensions of these tuyeres vary according
to the quantity of metal to be melted. The blast chamber is provided with sight
holes h opposite the several tuyeres, each closed by a sliding door fitted with a blue
glass, through which when closed the progress of the operation may be watched,
and when opened the tuyeres cleared.
At a certain distance above this row of tuyeres there is another row of smaller
size, also inclined downwards, and communicating with the blast chamber f by
means of tubes j furnished with stop-cocks i; k, sight holes closed by doors fitted
with blue glass, and sliding in grooves cast on the tubes j; they answer the same
purpose as those h. The number of tuyeres in this upper row is also variable, and
depends on that of the lower row g, the number in the two rows being always
equal. The size of the upper tuyeres should be between one-fourth and one-third
that of the lower tuyeres g. These limits should not be exceeded, because on the
one hand if they are greater than one-third the quality of the metal is affected, and
on the other hand if less these upper tuyeres, which simply act as regenerators for
the gases, obliging them to burn within well defined limits, will cease to have any
useful effect, and the gases, imperfectly utilised, will cause an increased expenditure
of fuel. This mechanical arrangement for regulating the distribution of the blast
enables the workman to govern the operation in the most complete and methodical
manner.
The various advantages obtained by this Invention are as follows :-
-
1st. In all cupolas having several rows of tuyeres the iron first melted does not
run hot enough, and many founders producing articles which require the metal very
hot at the beginning of the operation have been forced to abandon the use of such
cupolas, as they were obliged to run the metal into pigs instead of into the moulds.
This want of heat is due solely to the fact that owing to the position of the upper
row of tuyeres the gases are free to ascend rapidly before the lower tuyeres have
had time to heat the melting chamber of the cupola, which abstracts the heat from
the iron first melted, and until this part of the cupola is sufficiently heated the iron
continues to be thus cooled. With the mechanical arrangement of this Invention
it is only necessary in order to have the iron hot enough from the beginning to shut
the stop-cocks i, so that the blast being through the lower tuyeres only the melting
chainber will be heated because these tuyeres are in proximity to the hearth; the
commencement of the melting will thus be retarded, and the metal when melted
meets with a higher temperature in the melting chamber than its own, and hence
instead of being cooled the metal is from the commencement fit for the most difficult
castings.
2nd. The obstruction of a tuyere is immediately remedied by shutting off the
blast through that tuyere. Such obstructions are due either to the charge or to the

page_text: quality of coke used, and when they occur occasion much trouble in clearing the
tuyere and restoring the proper working of the furnace; but with my Invention it
is only necessary, as before mentioned, to shut off the blast through that particular
tuyere by means of the stop-cock, whereupon the metal being no longer cooled by
the blast is heated to melting point, and the obstruction thus disappears in a few
minutes, after which the blast may be again turned on, and the normal working of
the furnace restored.
3rd. At the end of the operation the difficulty is to melt the metal of the last
charge without leaving any unmelted, and for this purpose it is necessary to shut
off the blast from the upper tuyeres as soon as the charge descends to about three
feet above these tuyeres, so that the metal, which might otherwise be cooled by the
blast of the upper row of tuyeres, runs down into the melting chamber raised to a
high temperature by the lower tuyeres.
The Invention further comprises a special arrangement for the employment of
liquid hydrocarbons for melting large blocks of cast iron; it consists of two reservoirs
m, m, located above the blast chamber f, and connected at their lower part with
two diametrically opposite lower tuyeres g by pipes provided with stop-cocks n for
conveying the hydrocarbons to these tuyeres. At the upper part of each reservoir
two short pipes or mouths are provided, of which one o, through which the reservoir
is filled, is closed by a plug or cover secured by a cross bar, whilst the other is
continued up by a tube p opening into the interior of the shaft in order to admit
the pressure therein and on to the surface of the liquid in the reservoir m to balance
that coming through the tube n below. A sliding valve at the base of pipe p
cuts off the communication with the reservoir. When it is desired to use the
hydrocarbon as fuel the valve is opened and also the cock beneath. The liquid then
descends by its own gravity to the tuyere, where it is taken by the blast and
conveyed into the interior of the furnace. In contact with the coke and melted
metal it ignites, producing great heat, which assists the melting. As in ordinary
cupolas there is a door c at bottom. The furnace is braced at top by an angle iron
hoop, and is provided with a shoot to prevent injury to the lining in charging.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein-before in part recited Letters Patent is,-
In apparatus arranged and operating substantially as herein shown and described,
1st. distributing the blast to the lower tuyeres by a circular or annular chamber.
2nd. Governing the distribution of the blast to the upper tuyeres by stop-
cocks.
3rd. The method of introducing and employing liquid hydrocarbons, all as set
forth.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Ninth day of May, in the year of our Lord One
A. M. CLARK. (LS.)