Improvements in the Manufacture of Iron and Steel and in Apparatus therefor.
Year: 1889

page_text: Date of Application. 4th June, 1889-Accepted, 20th July, 1889
COMPLETE SPECIFICATION.
[Communicated from abroad by WILLIAM RICHARD JONES, of Braddock, in the
County of Allegheny, and State of Pennsylvania, United States of America.]
Improvements in the Manufacture of Iron and Steel and in Apparatus
therefor.
I JOHN THOMSON KING of 4 Clayton Square Liverpool in the County of Lancaster
Patent Agent, 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 :-
The primary object of my invention is to provide means for rendering the product
of steel works uniform in chemical composition. In practi e, it is found that metal
tapped from different blast-furnaces is apt to vary consi lerably in chemical composition,
particularly as regards silicon and sulphar, and such lack of uniformity is observable
in different portions of the saine cast, and even in different portions of the same pig.
The following table, giving the analyses of metal contained in different lille
charges, tapped from a blast furnace at a single casting, at the Elgar Thomson Steel
Works, at Braddock aforesaid, will illustrate the fact:--
Ladle No. 1 contained, Silicon 4.15 per cent.; Sulphur .015 %
Ladle No. 2 contained, Silicon 4.07 per cent.; Sulphur .02%
Ladle No. 3 contained, Silicon 2.89 per cent.; Sulphur .030 %
Ladle No. 5 contained, Silicon 1.23 per cent.; Sulphur .120 %
Ladle No. 6 contained, Silicon 2.52 per cent.; Sulphur .061 %
Ladle No. 7 contained, Silicon .66 per cent.; Sulphur .143 %
The consequence of this tendency of the silicon and sulphur to segregate or form
pockets in the crude metal is that the product of the refining process in the converters
or otherwise, in like manner lacks uniformity in these elements, and therefore
often causes great inconvenience and loss, making it impossible to manufacture
all the articles of a single order of homogeneous composition. Especially is this
so in the process of refining crude iron taken from the smelting furnace and charged
directly into the converter without remeiting in a cupola, and although such direct
process possesses many economic advantages, it has on this account been little
practised.
For the purpose of avoiding the practical evils above stated, I use in the refining
process, a charge composed not merely of metal taken at one time from the smelting
furnace, but of a number of parts taken from different smelting furnaces, or from
the same furnace at different casts, or at different periods of the same cast, and
subject the metal before its final refining, to a process of mixing, whereby its
particles are diffused or mingled thoroughly among each other, and the entire charge
is practically homogeneous in composition, representing in each part the average of
the unequally diffused and segregated elements of silicon and sulphur originally
contained in each of the several parts or charges. By proceeding in this way not
only is each charge for the refining furnace or converter homogeneous in itself, but
as it represents an average of a variety of uniform constituent parts, all the charges
of the converters from time to time will be substantially uniform, and the products
of all will be homogeneous. To this end, my invention may be practised with a
variety of forms of apparatus, for example, by merely receiving in a charging ladle,
a number of small portions of metal taken from several ladles or receiving vessels
-containing crude metal obtained at different times or from different furnaces, the
mixing being performed merely by the act of pouring into the charging ladle, an
other like means may, be employed. I prefer, however, to employ the apparatus
shown in the accompanying drawings, and without intending to limit the invention
to the use of that specific apparatus. I shall describe it particularly so that others
skilled in the art may intelligently employ the same.

page_text: DESCRIPTION OF THE DRAWINGS.
Fig. 1 is a vertical longitudinal section of the apparatus.
Fig. 2 is an end elevation of the mixing vessel and its actuating mechanism,
viewed in the direction of the arrow A of fig. 1.
Fig. 3 is a plan view of the parts shown in fig. 2.
Like symbols of reference indicate like parts in each view. 2 represents the reservoir
before mentioned. It consists of a covered hollow vessel, having an outer casing 3
of iron or steel, which is suitably braced and strengthened by exterior beams and
tie-rods as shown in the drawings. The whole interior of the vessel is lined with
firebrick or other refractory lining, which should be of sufficient thickness to retain
the heat of the molten contents of the vessel, and to prevent chilling thereof. The
vessel may be of any convenient size, holding say one hundred tons of metal, more or
less, and its shape is preferably such as shown in the drawings, being rectangular or
nearly so in cross section, and an irregular trapezium in longitudinal section. one
end being considerably deeper than the other. At the top of the deeper en 1, which I
call the rear end, is a hopper 5, into which molten metal employed in charging the
vessel is poured, and at the front end is a discharge spout 6, which is so located that
the bottom of the spout is some distance above the bottom of the vessel, say two feet
in a hundred ton tank, and more or less according to the capacity of the vessel; the
purpose of which is that when the metal is poured out of the spout, a considerable
quantity may always be left remaining and unpoured, and that whenever the vessel
is replenished, there may already be contained in it a body of molten metal with
which the fresh addition may mix. I thus secure, as much as possible, uniformity in
character of the metal, which is fed to and discharged from the tank, and cause the
fluctuations in quality of the successive tappings to be very gradual. For convenient
use of the apparatus, I have found it best to so arrange it that it is a lapted to receive
its charges of metal from cars or bogies 7, which run on an elevated track at about
the level of the normal position of the hopper 5, and to discharge its contents into
similar cars or bogies 1, on a track below the spout 6. In order to facilitate the
charging and discharging of the metal, the vessel is set on trunnions 8, which have
their bearings in suitable pedestals 9, and its rear end is provided with depending
rack bars 10, which are pivotted to the bottom of the mixing vessel and are in gear
with pinions 11, the shaft of which is connected by gearings 12 with the driving
mechanism of a suitable engine. The pinions are held in gear with the rackbars by idle
wheels or rollers 13. As the trunnions 8 are located on a transverse line somewhat
in advance of the centre of gravity of the vessel, it tends by its own weight to tilt
backwards into the position shown in fig. 1, but may be restored to a level position
by driving the pinions 11, and thus raising the rack bars 10 until the front part of
the bottom of the vessel comes in contact with a rest or stop 14.
The mode of operation of the vessel is as follows:-When the vessel is in the
backwardly inclined position shown in fig. 1, it is ready to receive a charge of metal
from the car 7. Before introducing the first charge, however, the mixing vessel
should be heated by internal combustion of coke or gas, and when the walls of the
vessel are sufficiently hot to hold the molten metal without chilling it, the said vessel
is charged repeatedly from the cars 7 with metal obtained either from a number
of furnaces, or at different times from a single furnace. The charges of metal
introduced at different times into the vessel, though differing in quality, mix together,
and when the vessel has received a sufficient charge, its contents constitute a
homogeneous molten mass, whose quality may not be precisely the same as that of any
one of its constituent charges, but representing the average quality of all the
charges.
If desired, the commingling of the contents may be aided by agitation of the vessel
on its trunnions, so as to cause the stirring or shaking of its liquid contents.
The shape of the mixing vessel (being deeper at its rear than at the front end as
before described) and its normal position when not discharging metal for the purpose

page_text: of casting, being with the bottom inclined upwards towards the front or discharging
end, and the bottom of the spout being situate above the bottom of the vessel at its
forward end, it is adapted to receive and hold a large quantity of molten metal without
its surface rising high enough to enter the discharge spout.
The hopper 5 is furnished with a movable cover 22, which when closed, serves to
exclude the outside air and to prevent the rapid cooling of the molten contents. If
care is exercised in keeping the hopper closed when the vessel is not being charged,
the metal can be kept in a fluid condition for a long time, the heat being kept up by
repeated fresh charges of molten metal, and if necessary or found desirable, by barning
gas introduced by a pipe or pipes into its interior.
After the vessel is properly charged, the metal is drawn off into the cars 15, from
time to time, as it is necled, by opening the door or cover 16 of the spout 6, and
driving the engine 12, so as to elevate the rear end of the vessel, and tilt it forward,
and thus to discharge any required amount of its contents in the manner before
explained, into the cars 15, which are transported to the converters, or the metal is
cast into pigs, or otherwise used. The tilting of the vessel does not, however, drain
off all the contents thereof, a portion being prevented from escaping by reason of
the elevated position of the spout 6, and as the vessel is replenished fro n time to time,
each new charge mixes with parts of previous charges remaining in the vessel, by
which means any sudden variations in the quality of the metal supplied to the converter
are avoided. Instead of discharging the metal into the cars 12, and carrying it in
the cars to the converters or casting-house, the vessel 2 may be so situate relatively to
the other parts of a furnace plant, as to deliver its contents immediately to the
converters, or other place where it is to be utilized.
I find it in practice very advantageous to employ two or more mixing vessels
constructed substantially as I have described, and to draw a portion of each converter
charge from each of the mixing vessels. My invention is, however, not limited to
the employment of two or any specific number of such vessels.
I shall now describe briefly other parts of the apparatus which are desirable and
important in its practical use, but which do not forin essential features thereof. At
the top of the vessel 2, are man-holes 17, designed to permit of access to its interior
for the purpose of repairing or fixing the lining. These holes are provided with suitable
covers 18, to exclude cold draughts or air from entering the interior. There is also a
hole 19 at the rear end of the vessel near the top, through which a rabble may be
inserted for the purpose of assisting or accelerating the mixing of the molten metal;
and at the other end, at the level of the bottom of the interior, there are holes 20,
provided with suitable spouts to enable all the molten contents to be drawn off when
it becoines necessary to do so (see fig. 5). The holes 20 should be provided with
suitable stoppers.
I do not desire to limit myself to the precise form of the apparatus which I have
shown and described, since many modifications in form and relative location of the
parts may be made by the skilled mechanic.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what 1
claim is :-
First. In the art of refining iron directly from the smelting furnace, the process
of equalizing the chemical composition of the crude metal, by thorcughly commingling
or mixing together the liquid metal charge and subsequently refining the mixed and
equalized charge; substantially as and for the purposes described.
Second. In the art of mixing molten metal to secure uniformity of the same in its
constituent parts, preparatory to further treatment, the process of introducing into a
mixing receptacle, successive portions of molten metal uniform in their non-metallic
constituents (sulphur silicon, etc.) removing portions only of the composite molten
contents of the receptacle without entirely draining or emptying the same, and
successively replenishing the receptacle with fresh uniform additions; substantially
as and for the purposes described.

page_text: Third. An apparatus for receiving and mixing successive charges of molten metal
previous to its further treatment or use, consisting in a covered vessel or receptacle
having a refractory and heat retaining lining, and provided with a charging hole and
a discharging hole or tap, from which the bottom of said vessel or receptacle is
downwardly inclined; substantially as and for the purposes described.
Fourth. An apparatus for receiving and mixing successive charges of molten
metal previous to its further treatment or use, consisting in a covered vessel or
receptacle, having a charging hole through which the molten metal is introduced,
and an elevated discharging hole or tap; substantially as and for the purposes
described.
Fifth. An apparatus for receiving and mixing successive charges of molten metal,
previous to its further treatment or use, consisting in a covered vessel or receptacie
provided with a discharge opening and mounted on permanent pivotal supports, and
a power engine connected with the said vessel or receptacle for tilting the same;
substantially as and for the purposes described.
Sixth. An apparatus for receiving and mixing successive charges of molten metal,
previous to its further treatment or use, consisting in a covered tilting vessel or
receptacle having a charging hole through which the molten metal is introduced, and
a discharging hole or tap, and a stop which limits the tilting of said vessel or receptacle
to prevent discharge of the entire contents when in use; substantially as and for the
purposes described.
Seventh. An apparatus for receiving and mixing successive charges of molten metal
previous to its further treatment or use, consisting in a covered vessel or receptacle
having a charging hole through which the molten metal is introduced, an elevated
discharging hole or tap, and a hole or holes at the base of the vessel for draining the
same, the bottom of said vessel being inclined downwardly from the discharge hole
or tap substantially as and for the purposes described.
Eighth. An apparatus for receiving and mixing successive charges of molten metal,
previous to its further treatment or use, consisting in a covered refractory-lined
vessel or receptacle having a discharge hole or tap, a charging hole, and a removable
cover for the latter; substantially as and for the purposes described.
Dated this 3rd day of June 1889.
Per Pro J. T. KING,
W. B. Johnson, Agent.