Note: Descriptions are shown in the official language in which they were submitted.
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Field of_the_Invention
The present invention is directed to the subject
matter of teeming valves for use on a vessel containing a
molten fluid, and more specificaly for a tundish utilizing a
sliding gate.
Statement of Relevant Art
_______________________ :
Reissue ~nited States patent 27,237 is representative
of the subject matter of sliding gate valves of the
character in which blank plates, or sliding gates with an
orifice are sequentially positioned beneath a vessel having
a top plate, and thereby can change from the on to the off
position. The subject reissue patent does not disclose,
however, a tube holder, much less a tube holder which can be
replaced during the course of a pour. Oftentimes a tube
holder will last two to three heats, and then needs to be
replaced. In accordance with prior practice, the tube
holder could only be replaced by placing a blank plate into
position, and shutting off all flow, and then thereafter
replacing the tube holder. This procedure costs the use of
a blank, plus it was slow. The present invention is
directed to this problem, and in addition, to the various
aspects of throttling which in one condition can accommodate
erosion, and in another condition, can accommodate the
clogging of an orifice depending upon the type of steel
being poured. These problems are, and the advantages of
throttling set forth, in copening Canadian patent
application S.N. 271,970, now Canadian patent 1,103,921.
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A further problem encountered by previous
constructions is the possibility of the formation of a fin
when changing gates. The fin can form between the sliding
gate and the top plate irrespective of whether the sliding
gate is a pour gate of a blank gate. Avoiding this
possibility is highly desirable.
In addition, when the pouring gates are changed, they
should be changed in such a fashion that there is not a
substantial increase in the flow rate. A substantial
increase in the flow rate of the molten steel could cause an
overloaded condition of a short box on the top of the
continuous caster which, in turn, can result in breakout and
stoppage of the casting.
Summary_
The present invention involves a method for changing a
tube holder, or a sliding gate in a valve each independently
of the other, and each as a function of the capability of
fully throttling the sliding gate by a lateral displacement
of the same. 'rhe sliding gate orifice is off-center making
the same assymetrical about one axis, and is proportioned
along with the tube holder as well as the top plate to
accomplish full shut-off immediately prior to closing the
drainage in the sliding gate into the tube holder. The
sliding gates are aligned by means of a magnet bar which, in
turn, is coupled to the throtting mechanism so that each
succeeding sliding gate is always in position and aligned
for replacing the operative sliding gate. The top plate is
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provided with a gas permeable plug and a manifold around
such plug to the end that gases, such as nitrogen, may be
passed therethrough in the fully throttled condition to
prevent freezing, and otherwise maintain the fluid in condi-
tion for resuming the pour after the sliding gate or the
tube holder is replaced. The structure is mounted on a
symmetrical frame casting, which, in turn, is secured to a
mounting place beneath the vessel.
A significant object of the present invention is
to provide a means for changing a pour tube assembly in
which the sliding gate is not replaced by a blank gate, and
then a subsequent sliding gate, thereby saving the handling
of and the cost of two sliding gates. In the traditional
operation the pouring gate is replaced by a blank gate, the
pour tube assembly then removed, and then a sliding gate
placed into position. Under these circumstances the operator
has to handle three parts, whereas by full throttling in
order to change the pour tube assembly, only one part needs
to be handled.
It is a principal object of the present invention
to provide a method for changing tube holders in less than
one minute, and minimize problems relating to the shutoff
for resuming the pour without clogging.
Another object of the present invention is to
provide a method for changing sliding gates in any stage of
throttling to duplicate the position of the previous sliding
gate.
Yet another object of the present invention is to
provide a sliding gate valve mechanism which will permit
throttling from full open to full closed, and intermediate
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positions, with adequate tooling for the mechanism and tube
holder .
Yet another object of the present invention is to
provide a valve for a sliding gate and a replaceable tube
holder which has two principal frame members, a bilaterally
symmetrical frame casting, and a bilaterally symmetrical
mounting plate which is secured to both the vessel, as well
as the frame member.
Description of Illustrative Drawings
Further objects and advantages of the present
invention will become apparent as the following description
of an illustrative embodiment proceeds, taken in conjunction
with the accompanying drawings in which:
FIGURE 1 is a longitudinal sectional view of the
subject valve taken in the full throttling condition, thereby
showing the sliding gate as blocking the flow of fluid.
FIGURE 2 is a transverse sectional view of the
same valve, in comparable scale, also showing the full
throttling configuration with the sliding gate orifice
plainly visible.
FIGURE 3 is a partially broken, partially diagramma-
tic view of the mounting plate illustrating the varlous
paths for flowing gases through the unit, as well as the
mounting means.
FIGURE 4 is a perspective partially sectioned view
of the top plate, showing the same in a configuration which
requires rotation 90 to be in its exploded perspective
relationship with FIGURE 3.
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FIGURE 5 iS a plan view of the sliding gate showing
the centerline, length, width, and extent of eccentricity of
the positioning of the pouring orifice.
FIGURE 6 is a perspective view of the sliding gate
shown in FIGURE 5, and approximately the same dimension.
FIGURE 7 is a top perspective view of the frame
casting as machined, illustrating the various means for
mounting to the mounting plate, and other components employed
in the valve construction.
FIGURE 8 is a bottom view of the frame shown in
FIGURE 7, with the same rotated counter-clockwise approximately
90 from the position shown in FIGURE 7.
The Method
The method of the present invention will be under-
stood after a brief description of its environment is set
forth. As noted in FIGURE 1, the full throttling valve 10
- is secured to the base of a vessel 11, and more particularly
to a bolt circle (not shown) on the base 12 of the vessel.
The vessel itself has the traditional pour opening 14, and
positioned therebeneath in fluid communication is the sliding
gate 15, with the sliding gate feed assembly 16 shown at the
left hand portion of FIGURE 1. The throttling assembly 17
appears more fully disclosed in FIGURE 2, which actuates the
sliding gate 15 laterally. The ejection assembly 18 appears
in FIGURE 1 and is shown elsewhere in the other drawings in
greater detail. The sliding gate orifice, as noted in
FIGURE 2, is slightly smaller in diameter than the pour
opening 14 of the vessel, and also smaller in diameter than
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the bore 23 of the tube 21, which is contained in the tube
holder assembly 20, secured therein by means of the collar
22, and more specifically its shoulder 24 secured to the
mounting spider 25. The tube holder assembly 20 as well as
the sliding gate 15, and the top plate assembly 35 all have
peripheral metallic rings totally encasing the refractory,
and all having an essentially J or L shaped cross-sectional
configuration. The tube holder support assembly 27 engages
the tube holder frame 26 and through the spring loaded
mechanism yieldably urges all of the refractory members
upwardly ana in fluid tight relationship each to the other.
The method, as noted first in connection with
FIGURE 1, contemplates positioning a sliding gate into
position for pouring communication with the pour opening in
the vessel. Thereafter the orifice 19 of the sliding gate
may be shifted laterally for partial throttling, or to the
full throttling configuration as shown in FIGURE 2. At the
point shown in FIGURE 2, the tube holder assembly is shifted
out of position and replaced in the comparable fashion as
that of the sliding gate, with the exception that the tube
holder assembly 20 is always aligned vertically with the
pour opening 14 of the vessel 11. Alternatively, when the
sliding gate 15 is being replaced and the tube holder assembly
20 remains in place, a magnetic means is employed positively
coupled and aligned with the throttling mechanism to make
certain that the successive sliding gate 15 moves into the
valve 10 in positive alignement with the sliding gate which
is being replaced. The method further contemplates providing
a means for circulating an inert gas into the top plate
assembly 35 to the end that during the configuration of full
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shut-off such as shown in FIGURE 2, the inert gas can bubble
through the molten steel and thereby inhibit the formation
of a plug or other contaminants in the area which could
effect further pouring action.
The Sliding Gate
_ ________ _____
While the sliding gate 15 has been described broadly
in connection with the description of the method above, its
specifics will be also noted in FIGURES 5 and 6. There it
will be seen that the sliding gate 15 has an encasement of a
metallic frame 51 with an undercut portion 52 around its
entire periphery. The width and length are designated by
the letters W and L respectively. In a commercial
embodiment the width is approximately 10.9 inches and the
length approximately 12.9 inches, and the eccentricity E of
the mounting of the pouring hole 19 is 8.2 inches. A
typical pouring hole 19 has a three inch diameter, and thus,
based upon the above dimensions or their respective ratios,
accomplishes approximately a half an inch of overlap in the
full throttle configuration as shown in FIGURE 2. The
sliding gate is desirably formed from those materials set
forth in Canadian application S.N. 271,970, now Canadian
patent 1,103,921. To be noted also is the mortar 53
surrounding the refractory insert 54 of the sliding gate. A
slightly enlarged section of the mortar is underneath the
J-shaped frame, as best illustrated in FIGURE 2. This
permits a cushioning action in part when the throttling
takes place by means of the throttling header 98 as shown in
FIGURE 2.
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The Top Plate
The top plate assembly 35 is shown in substantial
detail in FIGU~E 4. There it will be seen that a metallic
frame 36 surrounds the entire top plate assembly 35, the
same having side walls 38 terminating in a bottom flange 39,
which totally surround the ceramic insert 40. An orifice
liner 41 is provided to define the top plate orifice 42, as
well as finish off the interior of the top plate. By
providing stepped rings 44 in the top plate insert 40 as
well as interiorly of the liner 41, a gas manifold ring 45
is defined. The orifice liner 41 is secured in place by
means of ring mortar 46, which is normally an acid type
mortar, to seal the same in place, and yet provide the gas
manifold ring 45 which, when gas under pressure is presented
thereto, permeates the orifice liner 41 as shown diagramma-
tically in the arrows in FIGURE 4. Here it should be com-
mented further, as set forth in the description of drawings,
that the top plate assembly 35 should be rotated 90 counter-
clockwise in order that it be in its correct exploded rela-
tionship to the mounting plate. The frame mortar 48 surround-
ing the insert 40 is comparable to that used in the sliding
gate. Finally, as to the top plate assembly 35, it will be
noted that a gas passageway 49 is provided interiorly to
communicate with the gas manifold ring 45, and terminate in
a gas port 50 which is positioned in pneumatic communication
with a source of gas, usually an inert gas such as nitrogen.
Tube Holder Assembly
The tube holder assembly is shown in both FIGURES
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1 and 2. Turning llOW to FIGURE 1, it Will be seen that the
tube holder assembly 20 has a depending tube 21 which, as
described above, has a tube collar at its upper portion.
The bore 23 interiorly of the tube is of substantially the
same diameter as the orifice 14 of the vessel. A shoulder
24 is defined at the lower portion of the tube collar 22,
and rests atop a spider 25. The spider is provided with a
plurality of bolt extensions which are welded at their base
to the underneath portion 28 of the metallic frame 26 for
the tube holder. A ring 29 depends from the base 28 of the
tube holder frame 26. The insert is of a material comparable
to that employed in the top plate assembly 35, and sliding
gate 15. The insert orifice 31 is complimentary to the tube
orifice 32, and a mortar 34 surrounds the insert 30 and
seals its relationship to the tube 21. The metallic frame
26, base 28, and ring 29 are of such a strength as to with-
stand the upward pressure of the tube holder support assembly,
and to accommodate transfer of the tube holder assembly 20
out of the valve 10 when the full throttle condition as
disclosed in FIGURE 2 is achieved.
The Valve Mount, _rame and Assembly
The mounting plate 55 which secures the valve 10
to the vessel 11, is shown in perspective in FIGURE 3.
There it will be seen that a center bore 56 is provided
which receives the top plate assembly 35. A gas passage 58
is provided interiorly of the top plate 55, terminating at
one end at the gas connector 59 which is supplied from a gas
exterior to the valve 10, and at its opposite end in a gas
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port 60 for communicating with the gas port 50 of the top
plate assembly 35 as shown in FIGURE 4. Bolt pockets 61 are
provided around the periphery of the top plate assembly 55
for supporting depending bolts which in turn support the
balance of the valve 10 as will be described hereinafter.
Spring air manifold 62 is provided interiorly of the top
plate assembly 55 and the air diverted by means of spring
nozzles 64 downwardly over the springs which secure the tube
holder support assembly 27 as will be described hereinafter.
The air connector 65 receives an outside source of air, and
delivers the same to the cooling ring 66. The cooling ring
67 is a metallic ring and positioned in place after the
cooling ring 66 has been machined, and the principal function
of the tooling ring cover is to assist in the machining and
assembly of the top plate assembly 55. Note that bolt hole
68, is provided in the bottom of the bolt pockets 61, as
shown in dotted lines in FIGURE 3.
The relationship between the top plate assembly 55
and the frame 75 is best illustrated in FIGURE 2, where it
will be seen that the bolt assembly 70 is secured at its
upper end in the bolt pocket 61 through the bolt hole 68 at
the top plate assembly 55. The bolt assembly 70 fits into
a nut pocket 71 in the underneath portion of the frame
assembly 75, and its head 72 supports the frame 75 through
the tensioning of the shank 74.
Turning now to FIGURE 7, the frame assembly 75
will be noted to have a top plate opening 76 in its central
portion, and a left or right loading station 78 adjacent the
opening 76. Sliding gate rails 79 are provided underneath
the frame assembly 75, and more specifically as shown in
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FIGURE 8. The sliding gate moves parallel to the rails into
position. The discharge station 80, also as shown better in
the underneath portion in FIGURE 8, receives both the sliding
gate 15, and the tube holder assembly 20 when the same are
removed as described in connection with the method above.
Air holes 81 are provided for the spring assembly for the
tube holder support assembly and receives air from the
spring nozzle 64 in the mounting plate assembly 55. The
mounting holes 82 receive the bolt assembly 70 as described
in connection with the mounting plate 55 in FIGURE 2. Push
rod ports 84 are at the side of the mechanism to receive the
operating portion of the throttling mechanism, and a stop
pin port 85 is also provided for the insertion of a stop pin
to terminate the travel of the sliding gate when it is
placed into position. Slide gate rail 86 i5 provided at the
loading station 78 in order to receive the slide gates from
left to right side for positioning and insertion. Similarly
the tube assembly rail 88 is also provided in the loading
station 78. The discharge rail 89 in the discharge station
80 receives both the sliding gate 15 and the tube holder
assembly 20.
Turning now to FIGURE 1, it will be seen that a
sliding gate guide is provided to engage the undercut portion
of the sliding gate and align the same for insertion into
operative position. The sliding gate bar is coupled directly
to the throttling mechanism, and consequently its use of
four pole magnets 92 insures that the sliding gate assembly
15 is in direct alignment with the throttled configuation of
the sliding gate valve 15.
Throttling is accomplished by means of a pair of
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opposed pistons 95 (see FIGURE 2 where the right hand piston
is not shown but is similar to the left hand piston). The
piston and its cylinder drive the throttling rod 96, in this
instance a pair of parallel rods, which engage a single
transverse header 98 having a lower rail offset 99 for
engaging the side walls of the sliding gate 15.
The entire assembly of sliding gate 15, tube
holder assembly 30, and top plate 35 are held in fluid tight
relationship by means of the tube holder support assembly 27
which, as shown in FIGURE 2, includes a plurality of rockers
100 which are pivotally engaged by a spherical washer lOl,
and a pivot bolt 102 secured to the frame assembly 75. Push
pins 104 are mounted interiorly of the frame assembly 55,
and are surrounded by a spring 105 which is cooled as described
above, terminating in a spring feed 106 which urges downward
pressure on the rocker 100, and is aligned by means of
spring guide 108.
The entire assembly is such that the frame assembly
75, as shown in FIGURES 7 and 8, are bilaterally symmetrical
about the axis of travel of the sliding gate. In addition,
dimensional stability of the various assemblies are insured
by means of the frame assembly 75 being a single casting,
albeit machined, but from a common datum. Cooling, and ease
of shifting of refractory members are provided by the mounting
plate assembly in conjunction with the associated elements.
The method, as set forth at the outset, permits the chaning
of a tube holder assembly in less than a minute, oftentimes
45 seconds. The same is substantially true with regard to
the sliding gate, which, can be duplicated in orientation by
a second sliding gate when replacement is desired.
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Although particular embodiments of the invention
have been shown and described in full here, there is no
intention to thereby limit the invention to the details of
such embodiments. On the contrary, the intention is to
cover all modifications, alternatives, embodiments, usages
and equivalents of the subject invention as fall within the
spirit and scope of the invention, specification and the
appended claims.
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