IMPROVEMENTS IN BLOWING ENGINES AND CUPOLAS
Year: 1877

page_text: LETTERS PATENT to Benjamin Walker and John Frederick Augustus Pflaum,
both of Leeds, in the County of York, Engineers, for the Invention of
"IMPROVEMENTS IN BLOWING ENGINES AND CUPOLAS."
Sealed the 20th April 1877, and dated the 14th February 1877.
PROVISIONAL SPECIFICATION left by the said Benjamin Walker and John
Frederick. Augustus Pflaum at the Office of the Commissioners of Patents on
the 14th February 1877.
BENJAMIN WALKER and JOHN FREDERICK AUGUSTUS PFLAUM, both of Leeds, in
the County of York, Engineers. "IMPROVEMENTS IN BLOWING ENGINES AND
CUPOLAS."
•
Our improvements in blowing engines consist in the application of 3 square
compressors fitted with pistons worked by 3 crank pins placed at equal divisions of
the circle so as to produce uniformity of blast. The advantages arising from the
square instead of the usual cylindrical compressors are the saving of port space, and
obtaining an easier inlet and outlet for the air, also greater facility of construction.
The steam piston for driving the blowing engine is coupled to the piston rod of the
middle compressor, which is joined by a suitable connecting rod to the middle
crank pin. The piston valves of compressors are made rectangular for the same
purpose that the compressor is made square, viz., to economize port space and
facilitate the construction.
Where it is desirable to have a very uniform blast, or where only one or two
compressors are used, we insert in the delivery pipe a syphon, which is filled to a
certain height with water. When the pressure of blast is unequal the pulsation
will cause the water in the syphon to rise and fall, and this will make the blast
more uniform.
Our Invention further relates to the construction of cupola furnaces for the
melting of iron and other metals. We place 4 or more boxes outside the cupola
and near its base. These boxes are each fitted with 2 tuyere holes, one near the,
top, the other near the bottom of the box. If a large quantity of metal is intended
to be melted in the cupola the lower holes are plugged up with fire-clay or other

page_text: material. If only a small quantity of iron has to be melted the upper holes are
plugged up and the blast enters through the lower holes. By these means we
effect a saving in coke every time the cupola is charged for the small quantity.
In the upper part of the cupola above the charging hole we form a fire-brick
chamber containing a number of metallic pipes. These pipes are cylindrical and
joined to one common ring at the top. Inside each of these pipes is a smaller pipe,
and these smaller pipes are joined in another ring. The blast from the blowing
engine enters through the last-named ring into the smaller pipes, and thence returns
through the larger pipes into the first-named ring and so on to the cupola tuyeres.
These pipes are fitted with suitable scrapers for removing soot or dust. When the
cupolas are only employed for a few hours we use a sinall supplementary fire, so
that the pipes and chambers in which the pipes are inserted are made hot. Some-
times we place this chamber, not in the upper part of the cupola, but on one side,
and the top of the cupola is fitted either with a bell and charged in the same way
as a blast furnace, or the top of the cupola is joined with a flue to the heating
chamber, and the cupola is charged in the ordinary way through a door. Some-
times we employ U pipes, such as are usually employed in the hot blast stove for
blast furnaces, except that we fit these pipes with a scraper. Two cupolas may be
arranged in connection with the chamber containing pipes for heating the blast.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Benjamin Walker and John Frederick Augustus Pflaum in the Great
Seal Patent Office on the 14th August 1877.
BENJAMIN WALKER and JOHN FREDERICK AUGUSTUS PFLAUM, both of Leeds, in
the County of York, Engineers. "IMPROVEMENTS IN BLOWING ENGINES AND
CUPOLAS.'
Our improvements in blowing engines consist in the application of three square
compressors fitted with pistons worked by three crank pins placed at equal divisions
of the circle so as to produce uniformity of blast. The advantages arising from the
square instead of the usual cylindrical compressors are the saving of port space, and
obtaining an easier inlet and outlet for the air, also greater facility of construction.
The steam piston for driving the blowing engine is coupled to the piston rod of the
middle compressor, which is joined by a suitable connecting rod to the middle
crank pin. The piston valves of compressors are made rectangular for the same
purpose that the compressor is made square, viz., to economize port space and
facilitate the construction.
Where it is desirable to have a very uniform blast, or where only one or two
compressors are used, we insert in the delivery pipe a syphon which is filled to a
certain height with water. When the pressure of blast is unequal the pulsation
will cause the water in the syphon to rise and fall, and this will make the blast
more uniform.
Our Invention further relates to the construction of cupola furnaces for the
melting of iron and other metals. We place four or more boxes outside the cupola
and near its base. These boxes are each fitted with two tuyere holes, one near the
top, the other near the bottom of the box. If a large quantity of metal is intended.
to be melted in the cupola the lower holes are plugged up with fire-clay or other
material. If only a small quantity of iron has to be melted the upper holes are
plugged up, and the blast enters through the lower holes. By these means we
effect a saving in coke every time the cupola is charged for the small quantity.
In the upper part of the cupola above the charging hole we form a fire-brick.
chamber containing a number of metallic pipes. These pipes are cylindrical and
joined to one common ring at the top. Inside each of these pipes is a smaller pipe,
and these smaller pipes are joined in another ring. The blast from the blowing.

page_text: engine enters through the last-named ring into the smaller pipes, and thence returns.
through the larger pipes into the first-named ring, and so on to the cupola tuyeres..
These pipes are fitted with suitable scrapers for removing soot or dust. When the
cupolas are only employed for a few hours we use a small supplementary fire, so.
that the pipes and chambers in which the pipes are inserted are made hot.. Some--
times we place this chamber, not in the upper part of the cupola, but on one side,
and the top of the cupola is fitted either. with a bell and charged in the same way,
as a blast furnace, or the top of the cupola is joined with a flue to the heating..
chamber, and the cupola is charged in the ordinary way through a door. Some-,
times we employ U pipes, such as are usually employed in the bot blast stove for:
blast furnaces, except that we fit these pipes with a scraper. Two cupolas may be.
arranged in connection with the chamber containing pipes for heating the blast.
In order that our said Invention may be most fully understood and readily.
carried into effect, we will proceed to describe the Drawings hereunto annexed..
DESCRIPTION OF THE DRAWINGS.
..
"Figure 1 is a plan and Figure. 2 is a side elevation, both partly in section, of a
triple blowing engine constructed according to our Invention, it is suitable for.
working cupola furnaces; Figure 3 is a section taken on the line 1, 1, in Figures 1
and 2; Figure 4 is a section taken on the line 2, 2, in Figures 1 and 2.
}
a, a, a, are the three rectangular blowing "cylinders" or compressors; b, b, b, are.
the pistons working therein. Their piston rods are coupled by the connecting
rods c, c, c, with the crank throws of the crank shaft d, which are set at angular
distances of 120 degrees around the shaft; e is the cylinder which is supplied with.
steam to actuate the machine. The rod of the piston which works within the
cylinder e passes through a stuffing box in the bottom of the middle blowing
"'cylinder" or compressor, and is attached to the piston which works in it; f is the
eccentric upon the crank shaft from which the ordinary slide valve of the steam
cylinder receives its motion; and g. g, g, are the eccentrics for working the rect-
angular valves h, h, h, of the blowing "cylinders or compressors. The valves h
work over the ports a, a, a, in the "cylinders" or compressors, admitting atmo-
spheric air first to one side of the piston, then to the other. The three valve
chambers communicate the one with the other, and the air as soon as it passes
from the "cylinders "-or compressors is free to reach the opening i, from whence it
is led to the cupola or other place where it may be required for use.
"
Figure 5 is a side elevation partly in section of a cupola arranged according to
our Invention with apparatus for heating the blast; Figure 6 is a plan of the
same.
a is the body of the cupola, and b, b, are the tuyere boxes, of which there are
three, arranged at equal distances around the lower part. In Figure 6 however
two of these boxes are omitted in order that the cylindrical form of the body of
the cupola may more clearly appear. In each of the boxes b there are two tuyere
openings, one over the other, and either of them can be employed, according to the
quantity of metal which it is desired to melt; the hole which is not in use is
plugged. Doors are provided in the tuyere boxes to give ready access to the boles.
c is a trunk by which air is brought to the cupola from the blowing engine, and
d is another trunk by which the same air when it has been heated is led into the
tuyere boxes. The trunk c is connected with the ring e, into which the iron
pipes f, f, are fixed. These pipes descend into the interior of other iron pipes g
contained within a fire-brick chamber h constructed at the upper part of the
cupola. The pipes g, which are closed at their lower ends, are fixed to a ring pipe i,
with which they communicate, and the ring i is in connection with the descending
trunk d. The pipes g become highly heated by the flame of the cupola and the air
from the blowing engine, which is delivered into these pipes near their lower ends
by the interior tubes f takes up the heat, and in a heated state it rises up and
enters the ring i, and so passes to the tuyere boxes. k, k¹, are fire-ash doors, which

page_text: are employed only when first heating the chamber h. A fire-grate is inserted and
a small fire is established when it is needed.
Mechanical scrapers are employed to keep the surfaces of the pipes g clean, but
these scrapers being of well-known construction are not represented in the
Drawing..
Figure 7 is a vertical section and Figure 8 is a plan of another arrangement of
cupolas for heating the blast according to our Invention. Here one heating
chamber serves for two furnaces. The furnaces can both be worked at once, or
either of them may be shut off when desired. They are fed at the top by means of
cones, which when not open for feeding close the mouths of the furnaces. The
heating chamber in these Figures is represented with U pipes, one limb of each of
which communicates with the trunk in connection with the blowing engine, and
the other with the trunk for leading the heated air to the tuyeres. In place of
this arrangement however straight vertical tubes may be employed as in Figures 5.
and 6.
Having thus described the nature of our said Invention and the manner of per-
forming the same, we would have it understood that we claim,―
First. The construction of blowing engines with rectangular blowing "cylinders "
or compressors, substantially as described.
Second. The construction of blowing engines, substantially as described and
represented in the annexed Drawings.
Third. The construction of cupolas with air heating pipes ƒ and g for heating
the blast, as represented in Figures 5 and 6.
Fourth. The construction of cupolas in such manner that two furnaces may com-:
municate with the same chamber containing pipes for heating the blast, substantially
as described.
Fifth. The construction of cupolas, substantially as described and represented in
the annexed Drawings.
In witness whereof, we, the said Benjamin Walker and John Frederick
Augustus Pflaum, have hereunto set our hands and seals, this Eleventh day
of August, in the year of our Lord One thousand eight hundred and seventy-
seven.
:
B. WALKER.
(L.S.)
J. F. A. PFLAUM.
(L.S.)