Improvements in the Manufacture of Steel, and in the Refining of Fluid Iron.
Year: 1893

page_text: Date of Application, 27th Apr., 1893
Complete Specification Left. 23rd Jan., 1894-Accepted, 10th Mar., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Steel, and in the Refining of
Fluid Iron.
BENJAMIN HOWARTH THWAITE of Moorfields Chambers 95 Finsbury Pavement
London, E.C. Civil Engineer do hereby declare the nature of this invention to be as
follows:-
My invention relates to improvements in the manufacture of steel and in the
refining of fluid iron and consists in a novel mode of blowing or introducing
oxygen or admitting compressed oxygen or air alone or in combination with oxygen
into molten or fluid iron-
n-so as to effect the oxidation modification or elimination
of the usual metalloids, such as carbon, silicon, phosphorous and sulphur, and thus
either improve or modify the character of the iron or convert it into different
grades of steel.
The
Our invention may be applied on the treatment of large quantities of molten
metal but is more particularly applicable to the treatment of comparatively small
quantities of metal, and to facilitate the process, I have designed a useful form of
portable apparatus, which can be made and used without incurring the expense
incidental to the manufacture and employment of the usual large converters.
principle involved in my apparatus is that I am enabled to receive a small quantity
of the molten metal from the cupola into an ordinary or modified pouring ladle and
at once transfer the molten metal to a small adjacent converter where the metal is
subjected to a blast of oxygen or air or other gas which effects the desired changes
in the molten metal. The metal is again returned to the pouring ladle and the
ladle containing the converted metal is carried to the moulds. The apparatus
which I have designed to carry out these rapid shiftings of the metal from the
pouring ladle to the converter and again from the converter to the pouring ladle is
as follows: Upon a suitable carriage preferably running upon rails I mount a
strong shaft in bearings and upon this shaft I mount two strong bellcrank levers,
The
at the proper distance apart to accommodate the ladle and the converter.
pouring ladle is carried between two opposite arms of the two bellcrank levers and
the converter is similarly carried between the other two opposite arms of the bell-
crank levers. The converter may be fixed but the ladle should be so carried by
the arms that although it is held immovably during the operation of the apparatus.
it can at the same time be easily removed by means of the ordinary handles when it
is required to transport it to the moulds. The oxygen or air or gas is blown
through the bottom of the converter into the molten metal and through renewable
tuyere blocks made of compressed calcined magnesia or pulverised chrome ore or
siliceous material. The tuyere passages being specially formed and of very small
dimensions-not more than 1th of an inch in internal diameter-a cluster of such
passages being formed over one central supply passage. To permit of ready
removal and renewal of the tuyere blocks I apply a closed contracted chamber to
the foot of the converter which can be easily opened to permit access to the
tuyere blocks and permit the removal of any metal due to leakage. The oxygen air
or gas, is blown into this chamber through a pipe having a safety valve or through
The
flexible hose and from the chamber through the tuyeres into the metal.
tuyeres at the foot of the converter may however be disposed in any suitable
manner and we may arrange the tuyere openings so as to distribute the blast
laterally and cause a gyrating motion of the molten metal in the converter so as to

page_text: bring the oxygen, air or gases into more intimate contact with the metalloid
constitutents of the molten contents of the converter. Both ladle and converter
are lined with suitable refractory material. Upon the shaft carrying the two bell
crank levers we fix a worm wheel which gears with a worm on a shaft extending
alongside of the carriage. This shaft is provided with a hand wheel and the
result is that by turning the hand wheel and shaft the worm wheel and consequently
the frame composed by the two bell crank levers is rotated. One of the vessels is
thus lifted and the other lowered and as the converter and ladle stand at right
angles to each other, naturally the contents of the one are poured into the other
that is the higher vessel is emptied into the lower vessel. A bridge or conduit is
established between the two vessels to carry the molten metal from one to the
other. The oxygen or oxygen and air or other gaseous fluid blown into the
converter may be led from a source or from sources where it is stored under
pressure for example oxygen might be stored at high pressure in cylinders as is
usually done under Brins well known process and supplied to the foundry where it
is to be used; or the oxygen or gas or air might be blown into the converter in any
suitable manner.
When carrying my invention into effect the apparatus is run in front of the
cupola and the pouring ladle brought beneath the cupola delivering spout or
"lander." A supply of molten metal is then run into the ladle. The apparatus is
then run back from the cupola and the worm wheel shaft is turned so as to rotate
the frame and lower the converter into a vertical position and raise the ladle into a
horizontal position. The result is that the molten metal is poured from the ladle
into the converter.
The current of oxygen or air or other gas is then turned on and allowed to blow
through the tuyeres into the molten metal. I may also at this point add any
modifying constituents desired such for example as ferro-manganese. When the
metal has been sufficiently treated the current is cut off and the frame again rotated
so as to pour the converted metal back into the ladle whereupon the ladle is lifted
by its handles and taken to the moulds. I do not confine myself to the absolute
details of the apparatus so long as the main features are preserved namely the ease
and rapidity with which the molten metal can be transferred from the ladle to the
converter to be treated therein by the indicated means and again returned in its
converted state to the ladle. The apparatus herein before described is particularly
suitable for use in small foundries and works where it would be impossible to obtain
or use the larger types of converter.
:
In some instances and especially in cases where apparatus is used in treating
larger quantities of molten metal I might run the metal from the cupola direct into
the converter and after treatment run the converted metal into the pouring ladle or
into a succession of pouring ladles. In such cases either the apparatus already
described might be used or a different arrangement of apparatus embodying the
same principle. For example the converter might be made capable of being raised
vertically by hydraulic or fluid pressure or other means during or after or before
the process of converting the molten contents so that the metal when converted
could be run by gravity into a ladle or ladles on a lower level.
Of course it will easily be seen that the bottles or cylinders containing the
compressed oxygen or air may be attached to the converter carriage.
In commencing the blow-I prefer to employ air alone-until the metal has
covered the tuyeres so that in establishing a pressure-no oxygen is blown away or
wasted. After the pressure is established I turn on the oxygen.
い。
Dated this 25th day of April 1893,

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Steel, and in the Refining of
Fluid Iron.
I, BENJAMIN HOWARTH THWAITE of 95, Finsbury Pavement London Civil
Engineer do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
My invention relates to improvements in the manufacture of steel, and in
the refining of fluid iron, and consists in a novel mode of blowing or introducing
oxygen, or admitting compressed oxygen, or air alone, or in combination with
oxygen, into molten or fluid iron, so as to effect the oxidation modification or
elimination of the metalloids; such as carbon, silicon, phosphorus and sulphur,
either to improve or modify the character of the iron, or convert it into different
grades of steel.
My invention may be applied to the treatment of large quantities of molten
metal, but it is more particularly applicable to the treatment of comparatively
small quantities of metal, and to facilitate the process, I have designed a useful
form of portable apparatus, which can be made and used without incurring the
expense incidental to the manufacture and employment of the usual large
converters.
The principle involved in my apparatus, is that I am enabled to receive a small
quantity of the molten metal from the cupola, into an ordinary or modified pouring
ladle, and at once transfer the molten metal to a small adjacent couverter, where
the metal is subjected to a blast of oxygen, or air, or other gas which effects the
desired changes in the molten metal. The metal is again returned to the pouring
ladle and the ladle containing the converted metal' is carried to the moulder. The
apparatus which I have designed to carry out these rapid shiftings of the metal
from the pouring ladle to the converter, and again from the converter to the
pouring ladle is. as follows; Upon a suitable carriage, preferably running upon
rails, I mount a strong shaft in bearings, and upon this shaft I mount two strong
bell crank levers at the proper distance apart, to accommodate the ladle and the
converter; the pouring ladle is carried between two opposite arms of the two
bell-crank levers, and the converter is similarly carried between the other two
opposite arms of the bell-crank levers.. The converter may be fixed but the ladle
should be so carried by the arms, so that although it is held immovably during the
operation of the apparatus, it can at the same time be easily removed by means of
the ordinary handles when it is required to transport it to the moulds.
i
The oxygen air or gas is blown. through the bottom of the converter into the
molten metal and through renewable tuyere blocks made of compressed calcined
magnesia or pulverised chrome ore, or siliceous material.
The tuyere passages being specially formed and of very small dimensions say not
more than one sixteenth of an inch in internal diameter, a cluster of such passages
being formed over one central supply. passage.
To permit of ready removal and renewal of the tuyere blocks, I apply, a closed
contracted chamber to the foot of the converter which can be easily opened to
permit access to the tuyere blocks, and also permit the removal of any metal due
to leakage. The oxygen, air, or gas, is blown into this chamber through a pipe
having a safety valve, or through flexible hose, and from the chamber through the
tuyere into the metal. The tuyeres at the foot of the converter may however be
disposed in any suitable manner and we may arrange the tuyere openings so as to
distribute the blast laterally and cause a gyrating motion of the molten metal in
the converter, so as to bring the oxygen, air, or gas, into more intimate contact
with the metalloid constituents of the molten metal contents of the converter.

page_text: into a
Both ladle and converter, are lined with suitable refractory material. Upon the
shaft carrying the two bell crank levers, we fix a worm wheel which gears
worm fixed on a shaft extending, alongside the carriage. This shaft is provided
with a hand wheel, and the result is, that, by turning the hand wheel and shaft, the
worm wheel, and consequently the frame composed by the two bell-crank levers is
rotated. One of the vessels, is thus lifted and the other lowered, and as the
converter and ladle stand at right angles to each other, naturally the contents of
the one are poured into the other, that is, the higher vessel is emptied-into-the-
lower vessel; a bridge or conduit is established between the two vessels to carry
the molten metal from one vessel to the other. The oxygen or oxygen and air or
other gaseous fluid blown into the converter, may be led from a source or from
sources where it is stored under pressure, for example, oxygen might be stored at
high pressure in cylinders, as is usually done under Brins well known process and
supplied to the foundry where it is to be used; or the oxygen gas or air might be
blown into the converter in any suitable manner.
When carrying my invention into effect, the apparatus is run in front of the
cupola and the pouring ladle brought beneath the cupola delivering spout or "lander."
A supply of molten metal is then run into the ladle. The apparatus is then run
back from the cupola and the worm wheel shaft is turned, so as to rotate the frame
and lower the converter into a vertical position and raise the ladle into a horizontal
position. The result is, that the molten metal is poured from the ladle into the
converter. The current of oxygen or air, or other gas, is then turned on, and.
allowed to blow through the tuyeres into the molten metal.
I may also at this point, add any modifying constituents desired, such for example
as ferro-manganese. When the metal has been sufficiently treated, the blast is cut
off and the frame again rotated, so as to pour the converted metal back into
the ladle, whereupon the ladle is lifted by its 'handles and taken to the moulds.
I do not confine myself to the absolute details of the apparatus so long as the
'main features are preserved, namely, the ease and rapidity with which the molten
metal can be transferred from the ladle to the converter, to be treated therein_by
the indicated means; and again returned in its converted state to the ladle. The
apparatus hereinbefore described is particularly suitable for use in small foundries,
and works, where it would be impossible to obtain or use the larger types of
converter.
In some instances, and especially in cases where apparatus is used in treating
larger quantities of molten metal, I might run the metal from the cupola direct into
the converter, and after treatment, run the converted. metal into the pouring ladle
or into a succession of pouring ladles. In such, cases either the apparatus already
described, might be used, or a different arrangement of apparatus embodying the
same principle. For example, the converter might be made capable of being raised
vertically, by hydraulic or fluid pressure or other means, during, after, or before the
process of converting the molten contents, so that the metal when converted could
be run by gravity into a ladle or ladles onto a lower level. Of course it will be
easily seen that the bottles containing the compressed oxygen or air may be attached
to the converter carriage.
In commencing the blow I prefer to employ air alone, until the metal has
covered the tuyeres so that in establishing a pressure, no oxygen is blown away or
wasted.
In reference to the employment of magnesia for the tuyeres-1 form the
tuyeres in two portions, the upper one or that to be brought into contact with
the fluid metal; I make of calcined magnesia or lime, the lower portion or base
of such tuyere I make of silica-or fireclay-the two portions of the tuyere,
being baked together and dovetailed or otherwise formed so as to make a satisfactory
combination.
I make the tuyere blocks-either of magnesia, lime, or such other material, as is
not easily oxidised by the oxide of iron. When siliceous character of tnyere is
-used-I find that the oxide of iron produces with the silica, of the tuyere, a

page_text: fusible slag that rapidly corrodes away such siliceous character of tuyere. In order
to obviate this-I either employ calcined magnesia or calcined lime or chrome ore
compressed into tuyere formed by ordinary methods of compression.
Referring to the two sheets of drawings
Figure is a side elevation of the plant-Figure 2 being an end elevation
thereof.
A is the converter, B the receiving and mixing ladle. Both vessels being
mounted on bell crank shaped levers C-which are carried by the bearings D
mounted on carriage. The worm wheel E. is turned by the worm F fixed on &
shaft G, provided with a handle H-placed at such a distance on the shaft as to
enable the bell lever crank to be tipped-without any danger to the men.
The
worm wheel E is mounted on the arms of the trunnion on the belt that encircles the
converter B.
°
It will be observed that the converter B, is equipped with a tnyere box K in
which the oxygen and air or oxygen per se, accumulates, before passing through
the tuyere orifice L.
The tuyeres are held in position by the cross bars and screw handle H.
After the metalloids have been removed to the desired extent, the resultant
steel is run into the second vessel. The pouring angle being obtained by the
movement of the bell crank lever through the sweep of about a quarter of a
circle.
The connections from the compressed oxygen or air cylinder N to the chamber K,
is effected by means of the flexible and preferably armoured hose P.
Where a
thoroughly homogeneous mixture is required the receiving vessel B, can be moved
up and down so as to shake its liquid contents.
The connection of the flexible hose to the tuyere pipe is provided with a pressure
gauge R and in order to equalise the pressure in the tuyere, I may provide a gas
receiver between the compressed air and oxygen vessels.
When I utilise both air and oxygen I preferably provide a receiver, for the
purpose of effecting a mixture of the two gases-but when. not utilising this
receiver, I make the connection to the tuyere pipe-between the converter and the
storage vessels containing the oxygen or the air or both direct as shewn in Figure 2.
may mount the oxygen or oxygen and air cylinders or bottles N on the tail piece
of the converting carriage S. The skull or slag and residual metal can be run'or
be tipped into the pit T.
When the converting apparatus is required to be used, it is moved forward on
the rails U to the underside of the cupola lander V as indicated by the dotted lines.
When the metal is charged into the receiver B it is then tipped as already
described into the converting vessel A.
Having now particularly described and set forth the nature of my said invention
and in what manner the same may be performed, I will now proceed in specific
terms to declare the nature of my claims to novelty as follows:
First. The use of oxygen along with atmospheric air in the manner substantially
as described for the purpose of oxidising the metalloids existing along with
cast iron.
Second. The arrangement and combination of converter and receiving and
teeming vessel-mounted on a bell crank frame which is in its turn mounted on a
portable or movable carriage.
Third. The arrangement of compressed oxygen and air attachment to steel
converter-substantially as shown and described.
Fourth. The mixing vessel arrangement for bringing the air and oxygen together
before they reach the tuyeres.
Fifth. The arrangement of apparatus by which the converted metal or steel can
be made to flow from the converting vessel into the teeming or receiving vessel and
vice versa.

page_text: Sixth. The method of forming the tuyere of a combination of calcined
magnesia and fireclay or of magnesia-sand lime,-substantially as described.
Seventh. The method of fixing the steel receiving and teeming ladle in
combination with the converter, so as to enable the receiving ladle to be rapidly
removed to the moulds.
Eighth. The method of fixing the oxygen bottles on the converter carriage.
Dated this Twentieth day of January 1894.
B. H. THWAITE.