IMPROVEMENTS IN METALLURGICAL FURNACES AND PROCESSES." SPECIFICATION
Year: 1879

page_text: LETTERS PATENT to Lieutenant Colonel William Hope, V.C., of the Army and
Navy Club, Pall Mall, and Roswell Sabine Ripley, of the Westminster Palace
Hotel, Victoria Street, both in the County of Middlesex, for the Invention of
"IMPROVEMENTS IN METALLURGICAL FURNACES AND PROCESSES."
PROVISIONAL SPECIFICATION left by the said Lieutenant Colonel William
Hope and Roswell Sabine Ripley at the Office of the Commissioners of Patents
on the 27th October 1879.
Lieutenant Colonel WILLIAM HOPE, V.C., of the Army and Navy Club, Pall
Mall, and ROSWELL SABINE RIPLEY, of the Westminster Palace Hotel, Victoria
Street, both in the County of Middlesex. "IMPROVEMENTS IN METALLURGICAL
FURNACES AND PROCESSES."
The furnaces are improvements on the modified "air furnace," described in our
previous Specification, No. 1421, of the 9th of April 1879. We found on con-
structing a furnace as therein described for gas that the flame was not well placed,
so that too much heat escaped up the chimney, and also that to get the full
advantage of our process the flame ought to be carried round the outside of the
purifying pot to increase and maintain the heat in the melted metal for an unlimited
time. We also found that if we used any alkaline chemicals for purifying purposes,
they had a tendency to combine with the silica of the firebricks or ganister lining,
and so to act as a flux on the internal surface of the purifying pot, which at times
partially melted and ran down in combination with such chemicals as a vitreous
slag.
To remedy these various imperfections it was apparent that the flame must enter
in another manner in order that it might be carried round the outside of the
purifying pot; that the whole internal surface ought to be formed of a perfectly
neutral material, not merely infusible by any heat required for metallurgical
operations, but equally infusible by such heat although alkalies or acids may be
present; and further, that such material must be, to some extent, a conductor of

page_text: neat, or the neat could not penetrate from the outside of the purifying pot to the
liquid metal within.
On a review of all the materials now in use, or substances available, we found
that plumbago made into bricks of the ordinary size and shape of furnace bricks,
and built in with plumbago mortar, inside an outer casing of fire clay bricks,
would best meet our requirements. The plumbago for these bricks may either be
mixed with fire clay, as in the manufacture of crucibles, or with powdered steatite,
(soapstone,) or cryolite.
In our first improved furnace we preserve the same relative positions of the
purifying pot and melting shelf; but instead of introducing the gas and blast of
air into the purifying pot, we introduce them through, or at all events from the side
of, the chimney into the melting shelf, so that the flame may pass along the shelf
over a division or bridge down into the purifying pot, through a passage made by
the farther side of the said bridge and a wall resting on an arch forming the roof
in the central part of the purifying pot, and through which arched roof descends the
plunger blow pipe. At the top of this passage should be more gas burners and
air pipes for occasional use, as may be requisite. Then, after playing over the
surface of the charge of molten metal in the purifying pot, the flame ascends through
a similar passage on the other side of the central part of the roof, and descends on
the other side of the wall of the purifying pot farthest from the chimney, and so
through flues at both sides of the latter (at the level of the charge), and underneath
the bottom of the pot. It then passes up the outside of the purifying pot on the
side next the chimney, then through flues underneath, and on each side of the
melting shelf into the chimney, where it may be used to heat the gas and air
coming in.
In building a furnace of this description, especially if of small size, care must be
taken to support and strengthen the plumbago brick work in all places where it has
to encounter the weight of the metal by a chequer work of fire bricks in the flues
abutting on the solid outside walls.
The melting shelf should be long and narrow, so as to give the flame every chance
of searching through the material placed in it, and rapidly melting it. The
purifying pot should be deep and narrow, so that the chemical blast may rise up
through it in such a way as to permeate every part of the molten metal.
Advantage will be found from very carefully regulating the proportions, as well
as absolute amount of gas and air admitted. For instance, in the case of iron,
more or less impure, and containing both sulphur and phosphorous, it will be
better to have a slight deficiency of air, so that the flame will be a reducing flame,
as part of these substances will be carried off in combination with the hydrogen,
and a small addition of air should be added to the flame after it has passed through
the purifying pot, either at the top or the bottom of the second "passage," sufficient
to make the flame neutral, and, therefore, to maintain the maximum heat round the
outside of the purifying pot.
In the case of very impure pig iron the chemicals should be introduced into both
the melting shelf and the purifying pot, and so the former is made to assist the
latter. Instead of being "blown" in, they may be simply thrown in, and allowed
to form a slag on the surface. The iron in the shelf, after it has melted, may be
from time to time agitated and splashed up through the slag by a blast of hydrogen,
or say, the gas known as "Harkness gas," introduced from one or both sides or the
top. This may be effected either by short plunger pipes, like the large one in the
purifying pot, working either perpendicularly through the roof, or at an angle
through the sides, or by tuyers made to plunge in from the sides a short distance
at an angle. When the charge being simultaneously purified in the pot is finished,
the slag in the melting shelf should be tapped off. The metal may then be either
tapped direct into the pot, or through a tap hole conveying it round the outside,
and so into the pot. It should fall upon a fresh charge of chemicals, previously
introduced into the pot, and then the blast through the chemical blast pipe into the
pot should be of Harkness or other similar gas, acting partly on the phosphorous and

page_text: Then;
витрат спецпсацу, and partly and chieny mechanically as a mere stirrer.
when the other impurities are eliminated, the blast should be changed (the plunger
pipe being momentarily raised for the purpose) to air or oxygen, until the silicon
and carbon are, burned out. By maintaining a reducing flame during this latter
operation, any iron that may be oxidized will be again reduced. Or the operations
may be inverted, and the silicon and carbon burned out before the other impurities
are eliminated, in which case, a blast of air may be used as a “stirrer," but this is
not recommended, as the presence of the silicon and carbon assists in maintaining a
high state of fluidity while the purifying is going on.
Our second improved furnace differs from the above in detail of construction, but
not in principle or mode of working. The purifying pot is placed next the chimney,
and its plan is of the same general size and shape as that of the melting shelf.
The object is by spreading out the molten ore or metal to get a great extent of
surface for the flames to play over, while keeping the depth of metal very shallow,
coupled with the constant agitation of the blast, will maintain heat and fluidity
without the necessity of carrying the flames round the outside of the pot. In this
way the furnace may be built of any material that is sufficiently refractory without
regard to whether it conducts heat or not. The roof of the pot and the passages
for the entrance and exit of the flames will be just the same, only to ensure the
blast permeating the whole of the iron or other metal or melted ore there must be
two, three, or more plunger pipes, according to the length of the pot. In order to
keep the metal as shallow as possible in the pot, and also as evenly distributed as
possible, there should be very little inclination in the length of the pot, only just
enough to ensure the metal running out through the tap hole, but in order to assist
the flow the floor of the pot should also be inclined inwards from the sides to the
centre.
In all cases, whichever form of furnace is adopted, the melting shelf can always
be omitted if arrangements can be made for running molten ore or metal, iron, for
instance, direct out of a blast or other furnace. On the other hand the melting
shelf may be used to reduce ore as well as to melt pig iron or other metal.
The chemicals used are chalk, lime, or lime stone, whichever is cheapest, common
salt and caustic soda, generally in equal proportions, but the proportions of these
substances to each other, and also to the pig iron, must necessarily depend wholly
upon the composition of the particular kind of pig used, and in some cases one or
two of the above may be dispensed with; so also as to the length of time during
which the purifying process is continued. As regards the pressure at which the
chemical blast is blown in this must depend on the depth of the molten iron, but it
should be so adjusted as to thoroughly agitate and gently splash up the iron, but
not so as to splash it unnecessarily high, as, unlike the Bessemer process, the heat
being maintained there is no occasion for hurry.
It will be seen that furnaces of this kind may be constructed of unlimited size,
so that in the case of the heaviest cannon, armour plates, screw shafts, or other very
large castings, which it is intended to forge while liquid by rotation, the whole
mass of metal may be run out of the same furnace at exactly the same temperature.
For tapping the purifying pot it is recommended to adopt two tap holes, so to
say, one inside the other. The smaller one, which is manipulated like the tap of
an ordinary cupola furnace, is cut in a great wedge shaped block of steatite,
plumbago, or other brick, which is made to draw out occasionally in order to rake
out the slag. There should further be a manhole with a moveable cover at one
or both sides above the level of the molten metal, and one or both of these may
advantageously have a little window.
When it is desired to convert iron when isolated in a state of chemical purity
into steel, this may be done either by introducing spiegel-eisen into the pot, or by
blowing in powdered charcoal by Harkness or other similar gas, or by blowing in
gaseous carbon, as for instance, vapourised naphtha.
Or any other alloy, as for instance, chrome-steel, either of iron or any other
metal, should equally be made at this last stage,

page_text: "
The roof of the melting shelf should, as mentioned in our previous Specification,
be moveable for charging. Outside the plumbago portions of the above first
described furnace the very best non-conducting fire clay bricks, as for instance, the
'Dinas" bricks, should be used so as to prevent loss of heat by radiation.
The gas and air should be introduced in either of the above described furnaces
downwards at an angle of 45° at the top of the melting shelf at the end farthest
from the purifying pot, and they may be mixed together in huge Bunsen burners
of or cased with fire clay, steatite, cryolite, plumbago, asbestos, or a mixture of some
of these.
The plunger pipes may either be made altogether of plumbago or they may be
strengthened by a central wrought iron pipe, terminating in a swell, and protected by
a thick covering of asbestos, ganister, or some other non-conducting material inside
the plumbago, or they may be built up round a similar iron pipe of a mixture of
the substances indicated toughened with asbestos fibre. In all cases they must be
first dried very slowly and then baked. We have tried many different kinds of
material, but prefer plumbago strengthened with an iron pipe protected as
described. For the second of the above described furnaces, where the metal is very
shallow, the holes in the plunger pipes (if these are not open at the ends), should
be made sufficiently near the ends and pointing downwards, and the top ends of
the two, three, or more pipes should be fastened in an iron frame, so that they may
all be lifted simultaneously. For this arrangement the best way of connecting them
with the blast pipe is to carry the latter straight out over them at a suitable height,
and then to fill up between it and the plunger pipes with two or three lengths of
telescopic pipes, fitted with stuffing boxes or other similar arrangement adapted to
the pressure, and so preventing escape.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by.
the said Lieutenant Colonel William Hope and Roswell Sabine Ripley in the
Great Seal Patent Office on the 27th April 1880.
Lieutenant Colonel WILLIAM HOPE, V.C., of the Army and Navy Club, Pall
Mall, and RoSWELL SABINE RIPLEY, of the Westminster Palace Hotel, Victoria
Street, both in the County of Middlesex. "IMPROVEMENTS IN METALLURGICAL
FURNACES AND PROCESSES."
The furnaces are improvements on the modified "air furnace" described in our
previous Specification, No. 1421, of the 9th of April 1879. We found on con-
structing a furnace as therein described for gas that the flame was not well placed,
so that too much heat escaped up the chimney, and also that to get the full
advantage of our process the flame ought to be carried round the outside of the
purifying pot to increase and maintain the heat in the melted metal for an
unlimited time. We also found that if we used any alkaline chemicals for purifying
purposes, they had a tendency to combine with the silica of the fire bricks or
ganister lining, and so to act as a flux on the internal surface of the purifying pot,
which at times partially melted and ran down in combination with such chemicals
as a vitreous slag.
To remedy these various imperfections it was apparent that the flame must enter
in another manner in order that it might be carried round the outside of the
purifying pot; that the whole internal surface ought to be formed of a perfectly
neutral material not merely infusible by any heat required for metallurgical
operations, but equally infusible by such heat although alkalies or acids may be
present; and farther that such material must be to some extent a conductor of heat,
or the heat could not penetrate from the outside of the purifying pot to the liquid
metal within.
On a review of all the materials now in use or substances available, we found
that plumbago made into bricks of the ordinary size and shape of furnace bricks
and built in with plumbago mortar inside an outer casing of fire clay bricks would
best meet our requirements. The plumbago for these bricks may either be mixed
with fire clay, as in the manufacture of crucibles, or with powdered steatite
(soapstone) or cryolite.
In our first improved furnace we preserve the same relative positions of the
purifying pot and melting shelf, but instead of introducing the gas and blast of air
into the purifying pot we introduce them through, or at all events, from the side
of the chimney into the melting shelf, so that the flame may pass along the shelf
over a division or bridge down into the purifying pot, through a passage made by
the farther side of the said bridge and a wall resting on an arch forming the roof
in the central part of the purifying pot, and through which arched roof descends the
plunger blow pipe. At the top of this passage should be more gas burners and air
pipes for occasional use as may be requisite. Then after playing over the surface
of the charge of molten metal in the purifying pot, the flame ascends through a
similar passage on the other side of the central part of the roof, and descends on
the other side of the wall of the purifying pot farthest from the chimney, and so
through flues at both sides of the latter (at the level of the charge) and underneath
the bottom of the pot. It then passes up the outside of the purifying pot on the
side next the chimney, then through flues underneath and on each side of the
melting shelf into the chimney, where it may be used to heat the gas and air coming
in. Figure 1 of the Drawings annexed is a plan in section, and Figure 2 a vertical
longitudinal section of a furnace constructed as above described. In Figure 2 the
parts marked with sectional lines, set close together so as to appear darker than the
other parts, are made of plumbago. In building a furnace of this description the
plumbago brickwork in all places where it has to encounter the weight of the metal

page_text: is supported by a chequer work of firebricks in the flues abutting on the solid
outside walls. The plumbago brick work is thereby supported and kept in place,
whilst at the same time a free passage for the heated gases from the furnace is left
at the back of the plumbago brickwork.
A is the melting shelf; B, B, are three or it might be other number of pairs of
tubes set one within the other, and through which a blast of gas and air to be
consumed in the furnace is maintained.
Air is supplied through the annular space between the inner and outer tubes of
each pair, whilst Harkness or other gas is supplied through the inner tube; C is the
purifying pot of plumbago brickwork supported at the back by a checkerwork of
firebricks wherever required; D is a hanging bridge descending for a distance into
the purifying pot; E, E, are flues surrounding the sides and bottom of the
purifying pot and leading into a flue F below the melting shelf, and thence to the
chimney G; H is a tap hole from the melting shelf leading into the purifying pot,
and I a tap hole for drawing off metal from the purifying pot; K is a pipe coated
externally with plumbago, and which can be raised or lowered into the melting
pot and used for forcing air or other gas or vapour into the metal to be purified.
At L additional gas burners may be placed, from which a blast of flame can be
directed downwards into the purifying pot and increase the heat in this pot when-
ever required.
The melting shelf should be long and narrow, so as to give the flame every chance
of searching through the material placed in it and rapidly melting it. The purifying
pot should be deep and narrow, so that the chemical blast may rise up through it in
such a way as to permeate every part of the molten metal.
Advantage will be found from very carefully regulating the proportions as well
as absolute amount of gas and air admitted. For instance in the case of iron, more
or less impure, and containing both sulphur and phosphorus, it will be better to have
a slight deficiency of air so that the flame will be a reducing flame, as part of these
substances will be carried off in combination with the hydrogen, and a small
addition of air should be added to the flame after it has passed through the purifying
pot, either at the top or the bottom of the second "passage," sufficient to make the
flame neutral, and therefore to maintain the maximum heat round the outside of the
purifying pot.
When very impure pig iron is to be purified we introduce chemical substances,
such as hereinafter mentioned, into both the melting shelf and the purifying pot, and
so the former is made to assist the latter. The chemical substances may either be
"blown in by the aid of a blast of air or gas, or they may be simply thrown in
and allowed to form a slag on the surface. The iron in the shelf after it has
melted may be from time to time agitated and splashed up through this slag by a
blast of hydrogen, or say the gas known as "Harkness gas," introduced from one or
both sides or the top. This may be effected either by short plunger pipes like the
large one in the purifying pot, working either perpendicularly through the roof or
at an angle through the sides, or by tuyeres made to plunge in from the sides a
short distance at an angle. When the charge being simultaneously purified in the
pot is finished, the slag in the melting shelf should be tapped off. The metal may
then be either tapped direct into the pot or through a tap hole conveying it round
the outside and so into the pot. It should fall upon a fresh charge of chemicals
previously introduced into the pot, and then the blast through the chemical blast
pipe into the pot should be of Harkness or other similar gas acting partly on the
phosphorus and sulphur chemically, and partly and chiefly mechanically as a mere
stirrer. Then when the other impurities are to be eliminated, the blast should be
changed to air or oxygen until the silicon and carbon are burned out. When the
blast is to be changed from one kind of gas to another the plunger pipe should be
momentarily raised out of the metal to allow of the requisite changes in the
connections between it and the gas supply pipes being made.
By maintaining a reducing flame during this latter operation. any iron that may
be oxidised will be again reduced, and still further to ensure this being effected it is

page_text: well to pass a blast of Harkness gas through it for a very brief space after the
completion of the decarburisation. Or the operations may be inverted, and the
silicon and carbon burned out before the other impurities are eliminated, in which
case a blast of air may be used as a "stirrer," but this is not recommended, as the
presence of the silicon and carbon assists in maintaining a high state of fluidity
while the purifying is going on.
Our second improved furnace differs from the above in detail of construction, but
not in principle or mode of working. The purifying pot is placed next the chimney,
and its plan is of the same general size and shape as that of the melting shelf. The
object is by spreading out the molten ore or metal to get a great extent of surface
for the flames to play over, while keeping the depth of metal very shallow, coupled
with the constant agitation of the blast, will maintain heat and fluidity without the
necessity of carrying the flames round the outside of the pot. In this way the
furnace may be built of any material that is sufficiently refractory without regard
to whether it conducts heat or not. The roof of the pot and the passages for the
entrance and exit of the flames will be just the same, only to ensure the blast
permeating the whole of the iron or other metal or melted ore, there must be two,
three, or more plunger pipes according to the length of the pot. Figure 3 shows a
vertical section of a furnace thus constructed. A is the melting shelf; B are
tubular gas burners; C is the purifying pot; H and I are tap holes, and K, K, are
pipes by which blasts of air or other gas may be forced into the metal in the
purifying pot. In order to keep the metal as shallow as possible in the purifying
pot, and also as evenly distributed as possible, there should be very little inclination
in the length of the pot, only just enough to ensure the metal running out through
the tap hole, but in order to assist the flow the floor of the pot should also be
inclined inwards from the sides to the centre.
In all cases, whichever form of furnace is adopted, whether the one shewn at
Figures 1 and 2 or the one shewn at Figure 3, the melting shelf can always be
omitted if arrangements can be made for running molten ore or metal, iron for
instance, direct out of a blast or other furnace, but in this case sufficient space
must be allowed to enable the flame to focus itself upon the purifying pot. On the
other hand the melting shelf may be used to reduce ore as well as to melt pig iron
or other metal.
The chemicals used are chalk, lime, or limestone, whichever is cheapest, common
salt, and caustic soda, generally in equal proportions, but the proportions of these
substances to each other and also to the pig iron must necessarily depend wholly
upon the.composition of the particular kind of pig used, and in some cases one or
two of the above may be dispensed with; so also as to the length of time during
which the purifying process is continued. As an example of the proportions in
which we should use the purifying chemical substances, we should use for an iron
containing say 1 per cent. phosphorous, about 1 per cent. by weight of chalk or
lime or lime stone, 1 per cent. common salt, and 1 per cent. caustic soda.
regards the pressure at which the chemical blast is blown in this must depend on
the depth of the molten iron, but it should be so adjusted as to thoroughly agitate
and gently splash up the iron, but not so as to splash it unnecessarily high, as,
unlike the Bessemer process, the heat being maintained there is no occasion for
hurry.
As
It will be seen that furnaces of this kind may be constructed of unlimited size,
so that in the case of the heaviest cannon, armour plates, screw shafts, or other
very large castings which it is intended to forge while liquid by rotation the whole
mass of metal may be run out of the same furnace at exactly the same temperature
and of exactly the same quality.
For tapping the purifying pot it is recommended to adopt two tapholes so to
say, one inside the other. The smaller one, which is manipulated like the tap of
an ordinary cupola furnace, is cut in a great wedge shaped block of steatite,
plumbago, or. other brick, which is made to draw out occasionally in order to rake
out the slag, or to tap and rake out the pure iron if sluggish in its flow from too

page_text: low a heat. There should further be a manhole with a moveable cover at one or
both sides above the level of the molten metal, and one or both of these may
advantageously have a little window.
When it is desired to convert iron, when isolated in a state of chemical purity,
into steel, this may be done either by introducing spiegeleisen into the pot, or by
blowing in powdered charcoal by Harkness or other similar gas, or by blowing in
gaseous carbon, as for instance vaporized naphtha.
Or any other alloy, as for instance chrome steel, either of iron or any other
metal, should equally be made at this last stage.
The roof of the melting shelf should, as mentioned in our previous Specification,
be moveable for charging. Outside the plumbago portions of the above first
described furnace, the very best non conducting fire-clay bricks, as for instance the
"Dinas" bricks, should be used, so as to prevent loss of heat by radiation.
The gas and air should be introduced in either of the above described furnaces
downwards at an angle of about 45° at the top of the melting shelf at the end
farthest from the purifying pot, and they may be mixed together in huge Bunsen
burners of or cased with fire clay, steatite, cryolite, plumbago, asbestos, or a mixture
of some of these.
The plunger pipes may either be made altogether of plumbago, or they may be
strengthened by a central wrought iron pipe terminating in a closed and perforated
swell, and protected by a thick covering of asbestos, ganister, or some other non-
conducting material inside the plumbago; or they may be built up round a similar
iron pipe of a mixture of the substances indicated toughened with asbestos fibre.
In all cases they must be first dried very slowly and then baked. We have tried
many different kinds of material, but prefer plumbago strengthened with an iron
pipe protected as described, and the holes may be drilled through the covering into
the swell of the iron pipe either radially or tangentially. For the second of the
above described furnaces, where the metal is very shallow, the holes in the plunger
pipes (if these are not open at the ends) should be made sufficiently near the ends
and pointing downwards, and the top ends of the two, three, or more pipes should
be fastened in an iron frame so that they may all be lifted simultaneously. For
this arrangement the best way of connecting them with the blast pipe is to carry
the latter straight out over them at a suitable height, and then to fill up between it
and the plunger pipes with two or three lengths of telescopic pipes fitted with
stuffing boxes, or other similar arrangement, and adapted to the pressure, and so
preventing escape at the joints.
Having thus described the nature of our Invention and the manner of performing
the same, we would have it understood that we claim,-
First. The construction and use of furnaces, both when provided with and when
constructed without the herein named melting shelf, substantially as herein before
described and illustrated at Figures 1 and 2 of the Drawings.
Second. The construction and use of furnaces, both when provided with and
when constructed without the herein named melting shelf, substantially as herein
before described and illustrated at Figure 3 of the Drawings.
In witness whereof, I, the said William Hope, have hereunto set my hand
and seal, this Twenty first day of April, in the year of our Lord One
thousand eight hundred and eighty.