Improvements in Apparatus for the Manufacture of Steel.
Year: 1899

page_text: Date of Application, 25th Apr., 1899-Accepted, 24th June, 1899
COMPLETE SPECIFICATION.
Improvements in Apparatus for the Manufacture of Steel.
I, GEORGE WILLIAM JOHNSON, of 47, Lincoln's Inn Fields, in the County of
London, Chartered Patent Agent, do hereby declare the nature of this invention
(which has been communicated to me from abroad by the Wellman-Seaver
Engineering Company, a Corporation organised under the laws of the State of
Ohio, United States of America, and engaged in business at New England
Building, Cleveland, Ohio, aforesaid), and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement
In the ordinary system of open hearth steel manufacture the furnaces are
usually charged with cold pig iron and scrap which are reduced to the molten
condition in the furnace, but recently experiments have been made in the way
of charging the furnaces with molten iron obtained directly from a blast furnace
or cupola, and while some of these experiments have met with considerable success,
the saving has not been all that was expected.
The saving at the blast furnace is sufficient to warrant the use of the direct
process where a small percentage of pig iron is used in the open hearth furnace,
and it has been found that when a large percentage of molten pig iron is used in
the open hearth furnace it takes about as long and requires about as much fuel
to reduce and eliminate the carbon and other impurities from the iron, as it does
when the iron is charged cold, for in the latter case, the iron, as it melts, comes
into contact with the lime, ore and other oxidising agents, and by the time it
is melted the impurities are nearly eliminated from it and the result is attained
without that violent reaction which takes place when the metal is charged in
the liquid form, which violent reactions are destructive of the furnace bottom
and lining and so cause material increase in the cost of repairs.
As the cost of iron is in most cases less than the cost of scrap it is desirable
to use a very large percentage of iron and a minimum amount of scrap, and the
object of this invention is to provide means whereby this may be effected without
the objections attendant upon the use of molten iron, and at the same time without
the expenditure of as great an amount of time and fuel as is necessitated when
pig iron is charged cold.
This object is attained in the manner hereinafter described with reference to
the accompanying drawings, in which
Figure 1 is a diagram representing a preferable form of steel making plant
designed for carrying out the invention;
Figure 2 is a sectional view, drawn to a larger scale, of part of the mechanism
employed;
Figures 3, 4 and 5 are respectively a plan, a longitudinal section, and a
transverse section of a multiple-mold charging box employed in carrying out the
invention; and Figure 6 is a diagram illustrating a modification of the invention.
Figure 1 shews a structure containing two blast furnaces 1 and 2, and along-
side of the casting house of each furnace, tracks for a wheeled truck carrying a
ladle 4 into which the molten metal from the blast furnace can be run through

page_text: a suitable spout 5 instead of being run onto the casting floor as usual. These
tracks unite in a single track 6 the grade of which is gradually raised so that the
track is finally supported upon the elevated trestle 7, as shewn in Figure 2,
and the ladle can discharge its contents into the rocking or tilting mixing
furnace 9 which may be of any suitable character, it being, however, of large
capacity and preferably provided with means for constantly heating it, and with
a supply of oxidising slag, whereby the desiliconisation, or partial desiliconisation
of the molten iron, poured into the same, may be effected.
This mixing furnace provides charges for the open hearth furnace having a
substantially uniform percentage of impurities, since the variations in the per-
centage of impurities contained in successive charges from the blast furnace are
corrected by the mixing furnace, the discharge from the latter containing an
amount of impurity representing the average of that contained in the successive
charges from the blast furnaces.
The discharge spout of the mixing furnace delivers into moulds 10 which are
arranged side by side in groups, each group or series of molds being held together
firmly in place by a casing 11 which surrounds the said moulds, and has at one
end a socket 12 for the reception of the end of the discharge bar of an open
hearth furnace charging machine such for instance as that shewn in Patent
No. 6210, dated March 20, 1896, each casing 11 with its group or series of moulds
thus forming a multiple-mould charging box which can be handled as a unit by
the charging machine.
These charging boxes are placed in any desired number upon a suitable wheeled
truck 13 adapted to a track 14 so that one charging box after another can be
moved beneath the spout of the furnace 9 until the moulds of all of the charging
boxes have been charged whereupon the truck with its charged boxes can be
run into the open hearth furnace house 15 and the contents of the charging boxes
can be delivered by means of the charging machine 16 into any one of the series
of open hearth furnaces 17 contained in the said house.
The charging boxes are in succession engaged by the charging bar of the
machine, lifted from the truck, thrust into the furnace, inverted so as to discharge
the contents, restored to normal position, withdrawn from the furnace, and
re-deposited upon the truck.
By this means the extremely expeditious handling of the metal can be effected,
and yet in being conveyed from the mixing furnace to the charging machine the
metal in each of the moulds of each charging box will, owing to its limited
bulk, become sufficiently cooled to retain its form, while at the same time it
will retain so much of its original heat that when it is charged into the open hearth
furnace it can be reduced to the molten condition in much less time and with
a much less expenditure of fuel than a charge of cold pig iron.
By thus charging small hot pigs of iron into the open hearth furnace with
charges of ore and limestone or other oxidizing or slag-forming materials, the
latter will be intimately mixed with the iron blocks, hence, as the said blocks
melt, the iron will come into intimate contact with the oxidizing agents and the
impurities will be eliminated, but the operation will be a gradual one and not
accompanied by those violent and destructive reactions which attend the elimina-
tion of the impurities from the iron when the latter is charged in the molten
state.
While the use of the mixing furnace is, for reasons before given, always to
be preferred, some of the advantages of the invention may be attained without
the use of such mixing furnace, and in Figure 6 is shown a diagram of a plant
in which the molten metal is run directly from a blast furnace, cupola, or other
melting furnace, into the moulds of the charging boxes and conveyed by the latter
to the open hearth furnace house to be charged into the furnaces contained in the
latter.
In some cases, a single charging box may be used instead of a multiple-mould
charging-box, but the latter is preferred.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. The combination of a furnace for melting or containing molten iron, a charg-
ing box, an open hearth furnace, a charging machine operating in conjunction
therewith, and means for conveying the charging box from the furnace which fills
the same to the open hearth furnace charging machine, substantially as herein-
before described.
2. The combination of a furnace for melting or containing molten iron, a
charging box containing a series of moulds, an open hearth furnace, a charging
machine operating in conjunction therewith, and means for conveying the
multiple-mould charging box from the furnace which fills the same, to the open
hearth furnace charging machine, substantially as herein before described.
3. The combination of a melting furnace, a mixing furnace, an open hearth
furnace, a charging machine operating in conjunction with the latter, a ladle for
receiving molten metal from the melting furnace, a charging box containing
a group or series of moulds for receiving metal from the mixing furnace, means
for conveying the ladle from the melting furnace to the mixing furnace, and
means for conveying the multiple-mould charging box from the mixing furnace
to the open hearth furnace charging-machine, substantially as hereinbefore
described.
Dotad this 25th day of April 1899
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.