Note: Descriptions are shown in the official language in which they were submitted.
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SLIDE GATE TUNDISH FLOW CONTROL
TECHNICAL FIELD
The present invention relates to the continuous casting
arts, and especially to tundish apparatus employing flow
control means and spout means. More particularly, this
invention is intended to replace the tundish spout and flo~
control means of the metering pin type. Unlike conventional
slide gate tundish valves, the embodiment of the present
apparatus disclosed is adapted for tundish end-wall mounting
in combination with a particular spout mounting method.
BACKGROUND ART
An important advance in the art of casting molten metals
wherein the molten metal was poured via a tundish was made
with the advent of refractory sliding gate valve assemblies~
U.S. patents number 3,997,090; 4,000,837; ~,003,561;
4,017,010; 4t037,762; 4,042,207; 4,051,589; 4,055,217;
~,063,668; 4,076,153; 4,07~,154; 4,077,457; 4,077,5~2;
4,079,869; 4,031,971; 4,096,976; 4,108,675; 4,116,372; and
4,131,219 are illustrative of the prior art, indicating a
relatively crowded artO Other patents of interest include
U.S. patents number 4,22~,506; 4,227,630; 4,234,036; and
4,257,542. Generally, the foregoing describe various
arrangements showing a sliding gate valve assembly intended
for use in controlling the flow of molten metals in which an
apertured sliding gate member is used to open and close a
molten metal flow path in which the sliding gate member is
composed of a refractory material. Straight nozzles are
always included to direct the flow o molten metal; they are
generally of a rather short length in comparison to their
diameters and are generally further characterized in that
they are relatively permanent elements of the flow control
apparatus, not intended for easy removal and replacementO
Such a configuration is quite satisfactory for the intended
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uses of the prior art, where the molten metals ar~
discharged into large ladles, large molds, or tundishes fro~
which the metal flow is further directed to one or mote
casting molds. Such apparatus is unsuitable to situations
where the tundish nozzle must intrude into a small castin~
mold cross-section at complex angles and still remain
capable of movement, as by manipulating the tundish.
DISCLOSURE OF INVENTION
The present invention contemplates a three-element slide
gate control valve apparatus sealingly engaged to a panel
member portion of a tundish or the like, wherein the three
elements each have a major aperture providing communicat;~
between the tundish and the valve outlet such that the
molten metal flowing out of the tundish may be controlled as
to the flow rate by restriction of the aperture area through
which the metal flows. The three elements are generally
planar, with the first and third being fixed in position and
the second being moveable therebetween such as by a fluid
cylinder or other equivalent manipulator means~ The third
or outer element includes quick release fastener means by
which a spout moun~ing plate may be rapidly removed and
replaced; the spout mounting plate fits over the sli~de gate
apparatus such that the spout aperture (and thus the spout
entrance) communicates with the tundish through the flo~
control valve. The spout may be rapidly changed by
actuating the sliding member to interrupt molten metal flow,
then the quick release fastener means are released, freeing
the old spout by freeing the spout mounting plate. The old
spout and its mounting plate are removed and replaced by a
new spout and mounting plate assemblyO The quick release
fasteners are then replaced, the slide gate path is opened,
and operations recommenced.
O~
It is contemplated by this inventiOn that a permeable
plug area may be incorporated into the sliding member to
permit interposing a permeable material between the two
fixed elements of the slide gate valve such that when a
short term interruption is required, a gas (such as
nitrogen, argon, or oxygen) may be bubbled through the
permeable material to avoid unwanted ~etal solidification in
the flow control apparatus. In an alternate embodiment,
multiple positions may be selected such that the sliding
gate element may present different sized communicating
passageways or combinations thereof with permeable metal
flow passageway obstructions throuyh which the gas may pass.
A tapered flat cotter key inserted in an elongated eye
in the spout mounting plate fastening pin, for example, is
one of many quick release fasteners which may be used to
secure the spout mounting plate. O~ course, the fastening
pin is preferably attached to the fixed portion of the slide
gate valve, the tundish, or both, as desired.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a plan view of the apparatus comprising the
present invention; and
Fig. 2 is an end elevation view of a tundish
apparatus incorporating the present invention.
BEST MODE OF CARRYI~iG OUT THE I~IVENl'ION
Turning now to Fig. 1 the slide gate tundish flow
control apparatus 10 may be seen in detail in a partial plan
view. The tundish 11 is seen in a configuration in which
the molten ~etal contained therein is permitted to pass
through an aperture 22 in an end or side wall of the tundish
11, which wall is in this example substantially vertical.
It is to be understood that the mechanism of the invention
is readily adaptable to other side or bottom walls or walls
not substantially either vertical or horizontal~
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The slide gate mechanism as shown comprises first plate
12, second plate 14, slide gate 13, clevis 21, and fasteners
15 and 16. First and second plates 12, 1~ individually have
major apertures therethrough 23, 27, while slide gate 13 may
have at least one and preferably a plurality of apertures
24/ ~5, 26, which may be tapered or otherwise restricted in
cross-section (not shown) or filled with a gas permeable
material which is molten metals impermeable. This invention
contemplates that the slide gate may be adapted such that
the aperture or apertures are arranged to provide for
manipulation thereof in either a linear or rotary fashion.
A tundish spout 20 is mounted securely to mounting plate
17, in which mounting plate aperture 28 communicates with
spout passageway ~9 to provide free mo~ement of the molten
metal therethrough.
First plate 12 is ~aintained in sealing engagement with
tundish 11 as is hereinafter described. Second plate 1~ is
urged into contact with slide gate 13 by fasteners 15, 16
which may as de~ired be spring loaded (not shown). This may
be accomplished by including compression springs between the
heads of fasteners lS, 16 and second plate 14 to permit a
modest degree of free relative movement between plates 12,
1~ and slide gate 13 while maintaining sealing contact along
the molten metal pathO The apertures 27; 23 of pl~ates 1~
and 12 are maintained in constant, fixed coaxial alignment
with tundish aperture 22. ~ plurality of bolt ~asteners
extend through plates 14, 1~ into the tundish 11 wall to
ensure maintenance of this coaxial alignment only two of
which 15, 16 are shown in this view. ~s shown in this view,
the slide gate 13 includes a plurality of major apertures
which can be manipulated into coaxial alignment with the
spout-to-tundish passageway through manipulation of slide
~ate 13 by clevis 21 which is affixed to s]ide gate 13. In
contemplated substitute embodiments, the slide gate 13 may
be rotated about a point in a circular manner to position
the gate as desired.
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The spout ~0 and spout mounting arrangement on plate 17
over alignmen~jquick-release fastening eye pins 18, 19 is
especially useful in the configuration disclosed in this
document, as spout changes have been discovered to be
inconvenient according to prior art mounting methods, and
due to the peculiar operating conditions in small cross
section casting on machines having moving narrow mold entry
approaches, spouts may require relatively frequent
replacement. The spout mounting plate 17 includes a major
metal flow aperture 28 and at least two mountinq pin
apertures through which quick release fasteners such as
guide and mounting eye pins 18, 19 protrude. The eye pins
have elongated rectangular eyes (30) therein adapted to
receive tapered cotter keys such that the spout mounting
plate 17 may be sealingly and securely fastened to the outer
slide gate plate 14. The tapered cotter keys are driven
into the elongated eye slot (30) of -the eye pins 18, 19
firmly, as with a hammer, to achieve the foregoing sealing
engagement.
Spout replacement is rapid and efficient; the slide gate
13 is actuated to block molten metal flow therethrough,
either by a refractory area of the gate or by a
gas-permeable material through which a stirring gas may be
bubbled, then the tapered keys are tapped free with~hammer.
The spout 20 and its mounting plate 17 are easily removed, a
replacement spout 20 and mounting plate 21 placed over the
eye pins, and the tapered cotter keys inserted into the
elongated eyes (30) and hammered gently but firmly in place
to lock the mounting plate 17 in operating position. The
slide gate 13 is then actuated to permit molten metal flow,
and casting may be resumed. The arrangement disclosed by
this invention permits the entire spout change operation to
be performed extremely rapidly.
Referring now to FigO 2 an end vie~ of a typical tundish
11 having the slide gate tundish Elow control apparatus 10
of the present invention mounted thereon is shown~ Note
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that a portion of the pouring spout ~0 is deleted ~r
clarity of certain fastener parts otherwise hidden from
view. The outer, or second plate 14 of the slide gate val~e
is shown, which is fas~ened in place by a plurality ~f
fastener means 15, 16 such as threaded fasteners or ~e
like, only two of which are shown; any larger number may ~e
used as required. The spout mounting plate 17, shown as
circular but which may be of any convenient shape, is
attached to second plate 14 by means of a plurality (two aFe
shown for example) of quick release fasteners. These may be
of any desired type, such as threaded, twist-to-lock, or ~s
shown) eyepins 18, 19 having elongated rectangular eyes (30r
Fig. 1) into which tapered cotter keys 31 are tapped into
place, as shown. The slide gate, hidden from view in thiis
figure, includes a clevis eye 21 attached thereto f~r
manipulation thereof~ A fluid operated cylinder 35 attached
to the front of tundish 11 includes a rod 34 and rod eye 33
which rod eye is pivotably attached within the clevis
bifurcations by a pin 32. Note that this arrangement is
exemplary in nature and not intended to limit the
configuration of the invention. For example, an alternate
arrangement might include manual or motor-driven
manipulation means In this configuration a slide gate is
shown which is linearly operated; while in al~ternate
conigurations the slide gate may be operated in a rotary
fashion to maneuver the desired face, element, or aperture
of the slide gate into the desired position in the molten
metal flow path. The various elements in contact wi~h the
molten metal may be formed of refractory material or may be
protected with refractory coatings.
Spout change i5 effected by operating the slide gate 13
(shown in Fig~ 1) into the closed position, or into a slide
gate position permitting a gas to be bubbled through a
gas-permeable element, and in which molten metal flow is
stopped. The tapered cotter keys (31, etc.) are dislodged
from their respective eye pin 18, 19 apertures (30, etc.)
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freeing the spout mounting plate 17 for rernoval. The spout
mounting plate 17, to which the spout 20 is mounted, is
remoYed by extracting same from mounting eye pins 18, l9. A
new spout and mounting plate is guided into place over eye
pins 18, l9 and tapered cotter keys 32 are inserted therein
to lock the new spout 20 and mounting plate 17 in place.
While the foregoing description o the present invention
is related in terms of molten metal flow control in the
metallurgical arts, it is clear that with only minor changes
and simple experimentation within the range of skills
possessed by an artisan, the invention is adaptable for use
with other flowable high temperature materials~
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INDUSTRIAL APPLICA~ILITY
The slide gate flow control apparatus as herein
described is useful in the high temperature flowable
materials arts, such as the metal casting arts, and more
particularly in those situations where accurate molten metal
~low control and relatively frequent spout replacement are
required. Frequent spout replacement is often required with
continuous casting apparatus wherein one or more of the
casting mold surfaces moves in contact with the solidifying
metal, and where the mold cross section is small, where
spout manipulation is desired, and/or where high temperature
metals are being cast.
