IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL, AND APPARATUS THEREFOR.
Year: 1879

page_text: LETTERS PATENT to Charles William Siemens, of No. 12 Queen Anne's Gate,
Westminster, in the County of Middlesex, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF IRON AND STEEL, AND APPARATUS THEREFOR.'
"
PROVISIONAL SPECIFICATION left by the said Charles William Siemens at
the Office of the Commissioners of Patents on the 16th December 1879.
CHARLES WILLIAM SIEMENS, of No. 12, Queen Anne's Gate, Westminster, in the
County of Middlesex, "IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL,
AND APPARATUS THEREFOR."
In reducing iron ore or puddling iron in a rotary furnace the semi fluid or partially
molten mass is apt to slide along the lining instead of being rolled over on itself, so
as to expose continually fresh surface and undergo suitable agitation. One part of
my Invention relates to means for remedying this defect, and at the same time
providing protection for the throat of the furnace, which is most exposed to the
destructive action of the heat, and ensuring the division of the puddled mass into
balls of convenient size for handling. For this purpose I provide at the back of the
rotating vessel an annular casing surrounding the throat, and from this casing I
lead two or more pipes along and within the refractory lining of the vessel to a
trunnion joint at the centre of the front of the vessel. In this trunnion joint I
provide a facing like that of a rotating slide-valve, with ports communicating with
those pipes, and also with a supply and discharge pipe connected to the trunnion,
the former from a water cistern, pump, or accumulator, and the latter leading to &
drain or other outlet. As the vessel revolves water flows by the trunnion ports
along some of the pipes to the annular casing at the throat of the furnace, and back
thence to the discharge, a circulation of water being thus secured, keeping the pipes
themselves and the furnace throat comparatively cool. Owing to the coolness of
the pipes extending along the interior of the rotating vessel a portion of the molten
material solidifies on them, encrusting them so as to form inwardly projecting
longitudinal ribs, which as the vessel rotates cause the pasty mass to roll and tumble
over on itself, thereby facilitating and promoting the reducing and puddling action.
In order to subdivide the mass into portions, so as to form balls of convenient size,
I make the pipes that extend along the interior surface of the furnace chamber with

page_text: several bends or expansions projecting inwards. The material encrusting those
bends or expansions forms mounds projecting from the general surface of the lining,
which as the chamber rotates have the effect of dividing the more or less viscid
mass into separate lengths, each of which by the rolling becomes formed into a ball,
The working door of the furnace occupies a place in its front out of the centre clear
of the trunnion, and also of the branch pipes radiating from it to the longitudinal
pipes. For charging the vessel it is turned to such a position that the door is above
the centre, and the charge may be shot into the vessel from an elevated platform.
When the balling is effected the rotating vessel is stopped in such a position that
the door is under the centre; the door is then opened and the balls are withdrawn.
The balls may either be shingled and treated in the usual way to produce
malleable iron, or they may be introduced into a bath of molten pig, according to a
known process for the production of steel.
Steel, whether produced in this manner or otherwise, as for example by conver-
sion according to the Bessemer process, when it is run into ingot or other moulds
is apt to be more or less porous or spongy in its structure, and means have been
devised for remedying this defect and for obtaining sound, dense, and homogeneous
steel castings. For this purpose the molten metal in the mould has been subjected
to pressure by means of a plunger forced into it, and it has also been proposed to
subject it to steam pressure. According to my Invention I apply pressure to the
molten steel in the mould in the following manner :-Providing in the first place a
very strong mould somewhat higher than is required for the charge of metal, so as
to leave a little space in the mould above the metal, and providing a cap or cover
which can be strongly and quickly fixed by an elastic fastening, such as a steel key,
on the top of the mould after the metal is run into it, I connect this cap or the
upper part of the mould with an accumulator in which water is kept by pumping
under considerable pressure, such as several hundred pounds on the square inch.
After charging the mould with the fluid metal I quickly secure the cover on the
mould, and then, by opening a cock or valve, I admit the water under pressure
into the space in the mould above the metal. At first the water, being caused by
the heat of the metal to assume more or less the spheroidal condition, does not
rapidly become converted into steam, but as steam is generated from it the elastic
fastening yields, allowing gradual escape, so that the pressure in the mould is
maintained within safe limits while the whole of the metal in the mould is subjected
to pressure. In the meantime a second mould may be filled with metal, and this
in its turn may have its contents subjected to pressure as above described, and so
with mould after mould in succession; and obviously the mode of compression above
described is applicable to steel, however produced, whether it be poured into the
mould from a crucible or from a converter, or directly, or by a ladle, from any steel
producing or melting furnace. One connecting pipe from the accumulator may
serve for several moulds, being made flexible or jointed to allow for its being
shifted; also it may have in the union by which it is connected to the mould a
valve which is opened by the act of connecting the union, and is closed by the act
of disconnecting it, and the orifice in the mould or cover may be provided with a
check valve.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles William Siemens in the Great Seal Patent Office on the 16th
June 1880.
CHARLES WILLIAM SIEMENS, of No. 12, Queen Anne's Gate, Westminster, in the
County of Middlesex. "IMPROVEMENTS IN THE MAnufacture of IRON AND STEEL,
AND APPARATUS THEREFOR.'
"
In reducing iron ore or puddling iron in a rotary furnace the semifluid or
partially molten mass is apt to slide along the lining instead of being rolled over on
itself, so as to expose continually fresh surface, and undergo suitable agitation.
One part of my Invention relates to means for remedying this defect, and at
the same time providing protection for the throat of the furnace, which is most
exposed to the destructive action of the heat, and ensuring the division of the
puddled mass into balls of convenient size for handling For this purpose I provide
at the back of the rotating vessel an annular casing surrounding the throat, and
from this casing I lead two or more pipes along and within the refractory lining of
the vessel to a trunnion joint at the centre of the front of the vessel. In thistrunnion
joint I provide a facing like that of a rotating slide valve with ports communicating
with those pipes, and also with a supply and discharge pipe connected to the
trunnion, the former from a water cistern, pump, or accumulator, and the latter
leading to a drain or other outlet As the vessel revolves water flows by the
trunnion ports along some of the pipes to the annular casing at the throat of the
furnace, and back thence to the discharge, a circulation of water being thus secured,
keeping the pipes themselves and the furnace throat comparatively cool. Owing to
the coolness of the pipes extending along the interior of the rotating vessel, a portion
of the molten material solidifies on them, encrusting them so as to form inwardly
projecting longitudinal ribs, which, as the vessel rotates cause the pasty mass to
roll and tumble over on itself, thereby facilitating and promoting the reducing and
puddling action. In order to subdivide the mass into portions, so as to form balls
of convenient size, I make the pipes that extend along the interior surface of the
furnace chamber with several bends or expansions projecting inwards. The material
encrusting these bends or expansions forms mounds projecting from the general
surface of the lining, which as the chamber rotates have the effect of dividing the
more or less viscid mass into separate lengths, each of which by the rolling becomes
formed into a ball. The working door of the furnace occupies a place in its front
out of the centre, clear of the trunnion, and also of the branch pipes radiating from
it to the longitudinal pipes. For charging the vessel it is turned to such a position
that the door above the centre, and the charge may be shot into the vessel from
an elevated platform. When the balling is effected the rotating vessel is stopped in
such a position that the door is under the centre; the door is then opened, and the
balls are withdrawn. The balls may either be shingled and treated in the usual way
to produce malleable iron, or they may be introduced into a bath of molten pig,
according to a known process for the production of steel.
Steel, whether produced in this manner or otherwise, as for example, by con-
version according to the Bessomer process, when it is run into ingot or other moulds,
is apt to be more or less porous or spongy in its structure, and means have been
devised for remedying this defect, and for obtaining sound, dense, and homogeneous
steel castings. For this purpose the molten metal in the mould has been subjected
to pressure by means of a plunger forced into it, and it has also been proposed to
subject it to steam pressure.
According to my Invention I apply pressure to the molten steel in the mould in
the following manner:-I provide a mould which may be of the ordinary form, but
should be of considerable strength, and if it be open as usual at the top and the
bottom I provide on it suitable lugs, so that the mould can be firmly secured to

page_text: the base block, and that a cover can be secured on the mould by bolts or otherwise.
The cover is made with an aperture, through which water can be injected into
the mould after it is charged with the fluid metal, the aperture being then
closed. At first the water being caused by the heat of the metal to assume more
or less the spheroidal condition does not rapidly become converted into steam, but
as steam is generated from it the metal in the mould becomes subjected to a high
pressure, which prevents the formation of cavities in the mass. In order to prevent
passage of steam to the sides of the mould, and thence down between these sides as
they expand, and the contained metal as it contracts, I make the cover with an
inverted cup or bonnet forming a projecting bell or cone under the cover, the lower
edge of which dips into the fluid steel in the mould; this cup should be coated
with loam or blacklead before use to prevent its adhesion to the fluid steel. In order
to limit the pressure within the mould the cover may be secured by an elastic
fastening, such as a steel key, or it may be provided with a safety valve, which
may be a spring valve capable of withstanding great pressure, the spring being
adjustable by a screw. When steel has been poured into the mould, and the
inverted cup cover fixed in its place, a measured quantity, say, one pound, of water
is injected through a hole in the cover, which may be that for the safety valve into
the mould on the top of the liquid steel; and in the interval of time during
which the water remains spheroidal the safety valve is fixed in the cover of the
mould, or the injecting hole is closed by a screw plug or stop cock. As steam is
generated in the confined space within the inverted cup, the pressure causes the
metal therein to be depressed and forced up into the narrow wedge shaped space
between the outside of the cup and the ingot mould, where it rapidly chills and stops
all exit, and the steam pressure continuing to accumulate in the inverted cup
compresses the fluid steel in the mould until the desired limit, which may be a very
bigh pressure, such as 1000 pounds per square inch, is reached as determined by the
adjustment of the safety valve. The water may be injected by a syringe, or by
connecting the aperture in the cover with a high pressure water service or
accumulator, or a measured quantity of water may be introduced into the mould in
a sealed jar or case thrown upon the fluid steel before the inverted cup cover is
fixed in position. Obviously instead of water other liquid or solid substances, such
as ammonium carbonate or mixtures of alkaline nitrates with charcoal, which when
heated generate vapours or gases of high tension, might be introduced into the
mould, care being taken that the substances employed are such as develop pressure
in a steady manner without explosive action, such solid substances instead of being
introduced in closed cases might be fused before hand and poured into the cup of
the cover so as to become consolidated therein, care being taken in this case to leave
a free communication to the safety valve. When the metal under pressure has
nearly set the fixing of the cover is eased and the pressure remaining under the cup
causes it to become detached from the steel casting, which can be removed from the
mould in the usual way. The mode of compression above described is obviously
applicable to steel however produced, whether it be poured into the mould from a
crucible or from a convertor, or directly or by a ladle from any steel producing or
melting furnace. Also it is obvious that it may be applied to cluster moulds, that
is to say, the arrangement described for producing the pressure would be applied to
a central mould which communicated at bottom by runners with a series of other
moulds closed at top, so that the pressure exerted on the metal in the central mould
would be transmitted through the runners to the other moulds.
DESCRIPTION OF THE DRAWINGS.

page_text: and pipes B as indicated by the arrows. In the interior of the furnace the pipes B
and their bends B' form projecting ridges and mounds covered with cinder or
molten ore which has set thereon owing to the presence of water in them, and these
ridges and mounds cause the pasty mass under treatment to tumble over on itself
and to be subdivided into portions, thereby facilitating and promoting the reducing
and paddling action by causing every part of the mass to be exposed to the intense
beat of the flame, and the particles of metal to be agglomerated into balls of con-
venient size for handling. Instead of one annular casing A, several separate
casings may be employed each having its circulating pipes, and there might be a
greater or less number of the pipes B and of their bends
Fig. 4 is a vertical section, and Fig. 5 a plan of an ingot mould arranged to
operate according to this Invention. E is the ingot mould secured to the base
block F by means of cotter bolts ƒ, ƒ, as shewn in the part section, Fig. 6; G is the
cover having a lip forming an inverted cup or bell g, which dips into the fluid steel
in the mould to which the cover is secured by the wedge g'; H is the safety valve,
shewn to an enlarged scalo at Figs. 7, 8, and 9, and I is the stop cock which may
sometimes be employed for injection of the liquid. The valve his held down by a
spring the pressure of which is adjusted by screwing the head h² down on a
washer h³ of certain thickness, so that if the valve should be taken to pieces the
desired pressure, such as 1000 pounds per square inch, may again be determined
by screwing the head down on the washer.
Figs. 10 and 11 show a modified arrangement in which the cup of the cover is
made with a cavity containing water to keep it cool and prevent its lower edge
from fusing together with the steel, and the safety valve is in the form of a rod
kept down by an adjustable weight or spring, part of the slide of the rod boing
flattened to form a passage for escape of gas or vapour when the pressure is sufficient
to raise the rod in opposition to the weight or spring; K is a piece of wood which
may be employed for the generation of gas when it is pushed down by the safety
valve rod on to the hot metal. This piece of wood may be made with a cavity k
containing substances such as water, ammonium carbonate, or pitch to assist in
generating vapour or gas to furnish the pressure required.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I would have it understood that I make no general claim
to the compression of molten steel by subjecting it to the pressure of elastic fluid
within the mould, but I claim,—
First. The construction of rotative furnaces with internally projecting tubes and
bends filled with water so as to be encrusted by molten material or cinder forming
ridges and mounds on the lining, substantially as and for the purposes herein set
forth.
Second. The combination of the tubes referred to in the preceding claim with a
water casing at the furnace throat, substantially as herein described.
Third. Subjecting molten steel in an ingot mould to the pressure of steam or
gases of high tension generated within the mould by the heat of the molten metal
therein, substantially as herein described.
In witness whereof, I, the said Charles William Siemons, have hereunto set
my hand and seal, this Fifteenth day of Juno, in the year of our Lord One
thousand eight hundred and eighty.
C. WILLIAM SIEMENS. (L.S.)