Note: Descriptions are shown in the official language in which they were submitted.
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DEVICE FOR INTRODUCING GAS INTO MOLTEN METAL
IN A WIDE ANNULAR STREAM
Back~round of the Invention
Technical Field:
This invention relates to device for insufflating gas
into a mass of molten metal.
Description of the Prior Art:
Prior structures of this type have generally employed
frusto-conical permeable plugs positioned in frusto-conical
cavi-ties in pocket blocks in the refractory lining of the
ladle. Typical devices may be seen in U.S. Patents 3,834,685,
4,053,147 and 4,462,576. The LaBate prior art patents Nos.
4,396,179, 4,481,809, 4,483,520 and 4,538,795 disclose non~
permeable refractory plugs of frusto-conical shape provided
with metal jackets and positioned in ~rusto-conical cavities
in pocket blocks. The LaBate U.S. Patent No. 4,632,367 of
Dec.30,1986illustrates a solid non-permeable refractory plug
of frusto-conical shape with a spacedmetal jacket positioned
in a frusto-conical shaped cavity in a pocket block with the
upper end of the plug and the jacket extending above the upper
surface of the pocket block to form a hot metal dam.
The present invention substantially improves the stirring
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efficiency of gas introduced into molten metal and the
me-tallurgica~ reactions that are responsive thereto due to
the substantially increased area o~ -the annular column of gas
-flowing upwardly through the mol-ten metal which is achieved
by the inverted frusto-conical shape of the solid plug, the
metal shell thereon and the inverted frusto-conical shape of
the cavity in the pocket block which very substantially en-
larges the area of the device through which the gas enters
the molten metal.
Description of the Drawin~s
Figure 1 is a vertical section through a portion o~ a
hot metal ladle showing the device installed therein;
Figure 2 is an enlarged vertical section through the device
illustrating the gas passageways therethrough indicated by
directional arrows;
Figure 3 is an enlarged transverse section of a portion
of the device seen in Figure 2 turned 90 therefrom;
~igure 4 is a cross section on line 4-~ of Figure 3;
and
Figure 5 is a vertical section wi-th parts broken away
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illustra-ting an extractor for removing the device of the
invention from a ladle.
Descri~tion of the Preferred Embodiment
In the form of the invention chosen for illustration
herein, the device for introducing gas into molten metal in
a wide annular stream is best illustrated in Figures 1 and
2 of the drawings wherein a bottom metal shell 10 of a ladle
has an opening 11 therein and an apertured safety plate 12
secured to the ladle 10 in registry with the opening 11.
Refractory bricks 13 :Eorm the usual refractory lining of the
ladle and a pocket block 14 is positioned in the lining and
surrounded by the refractory bricks 13 andtor rammed refrac-
tory as sometimes employed in hot metal ladle linings~ The
pocket block 14 has an inverted frustro-conical shaped cavity
15 therein. The diameter of the lower smaller end of the
inverted frusto-conical cavity 15 compares with openings 16
in the refractory bricks 13,which openings are in vertical
registry and are of the same diameter as the opening 11 in
the bottom 10 of the ladle.
An inverted frusto-conical impervious plug 17 having
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longitudina].ly extending circumferentially spacecd ribs 18
thereon spacing it from a metal or ceramic inverted frusto-
conical shaped ja.cket 19 is positioned in the inverted frusto-
conical shaped cavity 15 in the pocket block 14 so as to define
an annular gas passageway through the pocket block 14. An
inverted frusto-conical shaped stainless steel screen 20 is
preferably positioned between the jacket 19 and the ribs 18
and/or the inverted frusto-conical shaped impervious plug 17.
The inverted frusto-conical impervious plug 17 is
preferably precast of a suitable re:Eractory and has a first
generally U-shaped rod 21, the ends of the arms of which are
outturned partial].y embeddecl therei.n to form a handle by
which the device can be held and lowered into a ladle and
positioned in the appropriate shaped pocket block 14. A bolt
22 having a head portion formed of steel rods 23, some oE which
are L-shaped, is partially embedded in the impervious plug
17 and extencls outwardly of the lower end thereo~ as seen in
Figures 1 and 2 o~ the drawings. A section oE steel pipe 23
is attached to the external end o~ the bolt 22 by means oE
a trans~er spider 24 attachedto one end thereoE and carrying
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a nut 25 which is attached thereto. The bolt 22 threadably
engages the nut 25 and thus secures the impervious plug 17
to the pip8 23 which extends downwardly therefrom through
the openings 16 in the refrac-tory bricks 13 and through -the
safety plate 12 and the opening 11 in the ladle shell 10.
A secondary nut 26 is threadably engaged on the lower threaded
end of the steel pipe 23 and positioned in engagement with
the shell 10 of the ladle and thus securely holds the device
o~ the invention is desired position.
It will be observed that the construction is such that
the pocket block 14 and the refractory bricks 13 or the like
surrounding the same are held in desired position and the
frequent cracking or separation oE the re~ractory lining and/or
the pocket hlocks o~ the prior art is avoided which prevents
damage to the re:Erac-tory lining oE the ladle as o-therwise
occurs from the entrance of hot metal into such cracks, open-
ings and the like in the refractory lining adjacent the pocket
block. The formation of the device also prevents the impervious
plug 17 ~rom being pushed away from the refractory lining and
the pocket block and most importantly the upper end of the
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inverted frusto-conical impervious plug 17 in the inverted
frusto-conical shaped cavity 15 provides an unusually large
area against which pressure of molten steel serves to keep
the impervious plug 17 as well as the pocket block 14 in
tight position in the refractory lining of the ladle.
Still referring to Figures 1 and 2 of the drawings, it
will be seen that the steel pipe 23 provides a gas passageway
for a stirring gas, such as argon, and that at its lower end
it is provided with an attached coupling 27 having an interior
thread into which an argon gas line 28 is secured. The argon
gas line 28 leads to a source of argon gas under suitable
pressure as will be understood by those skilled in the art.
~rrows indicating gas flow are present in Figure 2 of the draw-
ings showing the argon gas flowing upwardly through the device
around the bolt 22 and into the area between the end of the
pipe 23 and the spider 24 below the smaller end of the i.nverted
~rusto-conical shaped impervious plug 17 which provides space
i.nsuring a sufficient flow of gas into the annular passageway
formed by the plug 17 and its spaced position with respect
to the inverted frusto-conical shaped cavity 15 in the pocke-t block
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14.
In Figure 3 of -the drawings, an enlarged section of the
upper end of the steel pipe 23, the spider 24 and the nut 24
threadably engaging the bolt Z2 may be seen, the figure being
turned 90 from vertical and it will be seen that a plurality
of angular support arms 29 are attached as by welding it to
the upper outer surface of the steel pipe 23 and extend along-
side and are attached to the metal and/or ceramic jacket 19.
Arrows in ~igure 3 :illustrate the ~low of argon gas or the
lil~e through the device and emphasize the area adjacent the
small end oE the inverted frusto-conical plug 17 which enables
the gas to Elow into the lower end o~ the circular passageway
definecl by the plug 17 and the cavity 15 in the pocket block
14 as hereinbe:Eore described.
lS Figure 4 is a section Oll line 4-4 of Figure 3 and illustrates
the upper end of the steel pipe 23, the spider 24, the nut
25 and the bolt 22 on which it is engaged.
It will occur to those skilled in the art -that modifica-
tions of the device for introducing gas into molten metal in
a wide annular stream can be made and in Figure 5 a modification
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comprises means for removing the device from the ladle as
illustrated in vertical section. In Figure 5, the shell of
a ladle 31 is apertured as at 32 and has a pair of bolts 33
attached thereto in depending relation. A bar 34 apertured
at is ends is positioned between the bolts 33 and engaged
thereon and nuts 35 on the bolts 33 will move the bar 34 from
the lower position shown in solid lines in ~igure 5 to an
upper position shown in broken lines and in doing so wili
engage a coupling 36 on the lower end of a steel pipe 37 which
extends upwardly through the opening 32 and through the refrac-
tory 38 in the ladle and carries the device of the invention on
i-ts uppermost end. By moving the nuts 35 upwardly on the
bolts 33 the upward movement of th0 bar 34 will thus forcibly
push the device of the inven-tion upwardly into the ladle and out
o:E its normal seated engagement in the inver-ted frusto-conical
cavity in the pocket block, all as illustrated in Figures 1
and 2 of the drawings and heretofore described and thus provide
for the quick and easy removal of the device when it is eroded
by molten steel and replaced. Replacement is made periodically
ZO when the device of the invention is eroded by the molten steel
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and the eroded device is simply removed ~rom the ladle after
being pushed upwardly into the same as just described. A
replacement device including a new assembly of the inverted
frusto-conical impervious pipe, the pipe depending -therefrom,
etc. is then positioned over the ladle by a suitable support
and lowered thereinto and pushed downwardly into the pocket
block 14, the bar 34 having been removed so as to permit the
reinstallation of the secondary nut 26 which holds the device
in position and the reattachment o~ the argon gas supply line
28 as will be understood by those skilled in the art.
In a working example of the invention, the area of the
upper end of the refractory plug and jacket is at least three
times as large as the lower end thereof such as 7~" at said
upper end and 2" at the lower end, with the cavity in the
pocket block slightly larger.
It will thus be seen that a device for introducing gas
into molten metal in a wide annular stream has been disclosed,
the device being capable of a substantially increased stirring
action by the creation of a wide annular gas stream as compared
with the prior art devices and incorporating fastening means
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insuring the positioning and reten-tion of the device in the
ladle or other hot metal vessel in which it may be installed.
Although but one embodiment of the present invention has
been illustrated and described, it will be apparent to those
skilled in the art that various changes and modifications may
be made therein without departing from the spirit of the inven-
tion.
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