U.S. patent application number 10/781272 was filed with the patent office on 2004-08-26 for vortex inhibitor with sacrificial rod.
This patent application is currently assigned to Tetron, Inc.. Invention is credited to Jacobs, Ross A., Koffron, Robert J..
Application Number | 20040164466 10/781272 |
Document ID | / |
Family ID | 25062273 |
Filed Date | 2004-08-26 |
United States Patent
Application |
20040164466 |
Kind Code |
A1 |
Koffron, Robert J. ; et
al. |
August 26, 2004 |
Vortex inhibitor with sacrificial rod
Abstract
An improved vortex inhibitor for separating slag from molten
metal during the discharge of molten metal through a nozzle
includes a uniform castable refractory body with a generally
tapering shape, a hollow chamber within the body and an elongated
sacrificial member. The hollow chamber receives the sacrificial
member or a mount for the sacrificial member. The refractory body
and the sacrificial member combination in molten metal has a
specific gravity less than the specific gravity of molten metal and
is positioned narrow end downward when supported in molten metal.
The hollow chamber can fill with molten metal to form a core that
aids in orienting the body in a narrow end downward position. The
sacrificial member align the with the area in which the vortex
forms and minimizes interference with the flow through the
discharge nozzle. The body preferably includes swirl obstructing
surfaces.
Inventors: |
Koffron, Robert J.;
(Farmington Hills, MI) ; Jacobs, Ross A.;
(Snowmass, CO) |
Correspondence
Address: |
BROOKS KUSHMAN P.C.
1000 TOWN CENTER
TWENTY-SECOND FLOOR
SOUTHFIELD
MI
48075
US
|
Assignee: |
Tetron, Inc.
Farmington Hills
MI
|
Family ID: |
25062273 |
Appl. No.: |
10/781272 |
Filed: |
February 18, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10781272 |
Feb 18, 2004 |
|
|
|
09761465 |
Jan 16, 2001 |
|
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6723275 |
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Current U.S.
Class: |
266/236 |
Current CPC
Class: |
B22D 43/002 20130101;
F27D 3/1536 20130101; C21C 5/4653 20130101 |
Class at
Publication: |
266/236 |
International
Class: |
C21C 005/42 |
Claims
What is claimed is:
1. A vortex inhibitor for molten metal pouring from a discharge
nozzle comprising: a uniform castable refractory body having a
generally tapering shape along a longitudinal axis from a base
toward a narrow end and a hollow chamber positioned longitudinally
to the body extending within the body; and an elongated sacrificial
member constructed to dissolve before substantially obstructing the
discharge nozzle and retained by the hollow chamber to form an
integral body; whereby the integral body combining the refractory
body and the sacrificial member has a specific gravity of about 2.3
to about 7.0, and is self-orienting in a narrow end downward
position when supported in molten metal.
2. The vortex inhibitor of claim 1 wherein protrusions extending
outwardly from the sacrificial member mount in the hollow chamber
to form an integral body.
3. The vortex inhibitor of claim 1 wherein crimps extending
outwardly from the sacrificial member mount in the hollow chamber
to form an integral body.
4. The vortex inhibitor of claim 1 wherein molten metal is disposed
within the hollow chamber upon introduction into the metal
receptacle.
5. The vortex inhibitor of claim 1 wherein the sacrificial member
is hollow.
6. The vortex inhibitor of claim 1 wherein the sacrificial member
is a solid bar.
7. The vortex inhibitor of claim 1 wherein an exposed surface of
the sacrificial member is coated with a refractory material having
a refractory coating thickness.
8. The vortex inhibitor of claim 7 wherein the refractory coating
thickness is less than about 9 millimeters.
9. The vortex inhibitor of claim 3 wherein the sacrificial member
is filled with a refractory material.
10. The vortex inhibitor of claim 1 wherein the body includes a
complex polygonal base.
11. The vortex inhibitor of claim 1 wherein the base is
hexagonal.
12. The vortex inhibitor of claim 1 wherein the base is
octagonal.
13. The vortex inhibitor of claim 1 wherein the specific gravity of
the elongated sacrificial member is in the range of about 3.5 to
7.9.
14. A vortex inhibitor for molten metal pouring from a discharge
nozzle comprising: a uniform castable refractory body having a
generally tapering shape along a longitudinal axis from a base
toward a narrow end and a shaft positioned longitudinally to the
body extending within the body; and an elongated sacrificial member
constructed to dissolve before substantially obstructing the
discharge nozzle and retained by the shaft to form an integral
body; whereby the integral body combining the refractory body and
the sacrificial member has a specific gravity of about 2.3 to about
7.0, and is self-orienting in a narrow end downward position when
supported in molten metal.
15. The vortex inhibitor of claim 14 wherein the shaft is
hollow.
16. The vortex inhibitor of claim 14 wherein the shaft is
solid.
17. The vortex inhibitor of claim 15 wherein the sacrificial member
contains external screw threads.
18. The vortex inhibitor of claim 16 wherein the sacrificial member
contains external screw threads.
19. The vortex inhibitor of claim 17 wherein an end of the shaft
contains internal screw threads, wherein the external screw threads
on the sacrificial member and internal screw threads are
matable.
20. The vortex inhibitor of claim 15 wherein the sacrificial member
contains internal screw threads and an end of the shaft contains
internal screw threads.
21. The vortex inhibitor of claim 20 further comprising a nipple
with external screw threads at each end, wherein the nipple mates
the sacrificial member with the shaft.
22. The vortex inhibitor of claim 18 wherein an end of the shaft
contains external screw threads.
23. The vortex inhibitor of claim 22 having a coupling containing
internal screw threads, wherein the coupling mates the sacrificial
member with the shaft, whereby the body and the sacrificial member
combination form an integral vortex inhibitor.
24. The vortex inhibitor of claim 14 wherein the sacrificial member
is hollow.
25. The vortex inhibitor of claim 24 wherein the sacrificial member
is positioned snugly over the shaft.
26. The vortex inhibitor of claim 14 wherein the shaft extends
partially within the body.
27. The vortex inhibitor of claim 14 wherein the specific gravity
of the elongated sacrificial member is in the range of about 3.5 to
about 7.9.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority of U.S. patent
application Ser. No. 09/761,465, filed on Jan. 16, 2001, published
on Jul. 18, 2002 as US 2002/0093128, issued on as U.S. Pat. No.
______, and entitled "Vortex Inhibitor With Sacrificial Rod".
FIELD OF THE INVENTION
[0002] The present invention relates to a device for separating
slag from molten metal as the molten metal is transferred from a
receptacle.
BACKGROUND ART
[0003] In metal making processes, a layer of slag comprising metal
impurities forms atop the surface of molten metal held within a
metal receptacle such as a furnace, tundish or ladle. As the molten
metal is drained from the receptacle, the flow of molten metal
through the discharge induces a swirl above the discharge nozzle.
At a critical level, the energy of the swirl creates a vortex,
whereby the slag layer is sucked into the nozzle, thus
contaminating the pour. Separation of the slag and molten metal
enhances the quality of the discharge.
[0004] Several devices have been known to inhibit the introduction
of the slag into the nozzle via the sucking effect of the nozzle.
Many of the previously known devices for restricting slag flow
through the discharge nozzle were in the form of a refractory body
and extending rod combination. For example, the abstract of German
Disclosure DE 19821981 A1 to Stilkerieg discloses a slag retainer
consisting of a closure body and a finned guide bar. The fin
elements consist of a refractory material, preferably a refractory
concrete. The closure body also has a bar protruding
perpendicularly upwards from the base of the closure body. This bar
is attachable to an arm which positions the slag retainer over the
tapping channel. Although suitable for its intended purpose, the
fin elements are expensive to fabricate. Therefore, the use of a
finned guide bar substantially increases the costs of metal making.
Moreover, the extending rod enters the tap hole and stifles the
flow of molten metal through the nozzle during the pouring process.
Consequently, metal pouring operation using this refractory body
and extending rod combination extends processing time, and thus
increases production costs.
[0005] U.S. Pat. No. 4,799,650 to LaBate discloses a slag retainer
consisting of a tapered, circular refractory closure having a
tapered, hexahedron-shaped, refractory extension. The circular
closure is sized sufficiently to close the tap hole. A metal rod is
passed through the center of the circular closure and extends
downwardly into the elongated hexahedron shaped extension to join
the circular closure and the hexahedron-shaped extension. The
hexahedron extension prematurely throttles the flow of molten metal
through the discharge nozzle. Consequently, a significant amount of
usable molten metal remains in the receptacle after the pour is
stopped, substantially decreasing the total molten metal released
per pour, and thus increasing operation costs.
[0006] U.S. Pat. No. 4,494,734 to LaBate et al. discloses a slag
retainer with a modified cone-shaped refractory body and a rod. The
rod extends below the center of the body and is covered with
refractory sleeves. The upper extension contains a swivel mechanism
which is used to engage a mechanical device that positions the slag
retaining device over the tap hole. The patent also covers a method
of minimizing slag carryover by dropping a body having a plurality
of generally irregular faces and a guide means within a restricted
area, draining a furnace, monitoring the stream for flaring, and
shutting off flow through the tap hole. Unfortunately, continuous
intrusion of the guide means extends the time for discharging metal
and may encourage operators to prematurely terminate the flow of
the molten metal. Additionally, the process of constructing and
affixing refractory sleeves to the downward extension significantly
increases the cost of manufacturing the slag retainer.
[0007] U.S. Pat. No. 4,709,903 to LaBate discloses a slag retainer
consisting of a barrel shaped refractory body and a rod. The rod
extends vertically through the barrel shaped body and upwardly and
downwardly thereof. The upward extension is engaged to a mechanical
device used to position the slag retaining device over the tap
hole. The downward extension is covered with refractory sleeves.
However, the downward extension enters the tap hole and continues
to prematurely restrain the flow of molten metal through the
discharge nozzle. Consequently, as previously discussed, the
problem of premature termination of the pour results. The problems
of shaping and assembling previously discussed are also
encountered.
[0008] U.S. Pat. No. 4,610,436 to LaBate, II et al. discloses a
slag retaining closure having a tapered body and an elongated guide
means consisting of an elongated guide member and tip portion
depending from the closure. A tip portion of the guide member
having a recess or a cavity accelerates and aligns the guide member
with the tap hole. The portion of the guide member extending below
the tapered end of the closure is coated with refractory sleeves.
As with the other disclosures, operation costs are increased due to
premature throttling and pour termination. Moreover, the use of the
intricate elongated guide means substantially increases
manufacturing complexity and has been disfavored.
[0009] The previously known refractory body and extending rod
combinations suffer from additional disadvantages. These
combinations require pre-assembly. The resulting unit requires
special packaging to ensure that the extending rod does not break
off during delivery. Additionally, the cumbersome shape of the body
and rod combination decreases the amount of units that can be
shipped in any given space. Moreover, the elongated rods of
existing devices may strike the wall of the receptacle instead of
entering their intended position in the tap hole. Since the vortex
forms above the tap hole, incorrectly positioned devices have
little or no effect on inhibiting the vortex. The shipping and
operational problems contribute to a lack of industry acceptance of
vortex inhibitors with a body and rod combination.
SUMMARY OF THE INVENTION
[0010] The present invention overcomes the abovementioned
disadvantages by providing a vortex inhibitor using a refractory
body with a hollow chamber adapted to receive a sacrificial member.
The vortex inhibitor has a specific gravity less than the specific
gravity of molten metal and is self-orienting in a narrow end
downward position in a molten metal bath. The sacrificial member
does not inhibit the flow of the molten metal since it can
dissipate shortly after introduction into the metal bath.
Additionally, even if the sacrificial rod strikes the wall of the
receptacle, the rod can dissipate shortly after introduction into
the receptacle, thus freeing the body to relocate to the area in
which the vortex forms. Furthermore, the sacrificial member may be
constructed of inexpensive metal rod, bar, pole, or other types of
elongated members such as tubes, rather than the intricate and
expensive guide systems of the prior art.
[0011] In general, the vortex inhibitor of the present invention
comprises a tapering, castable refractory body, a hollow chamber
positioned longitudinally to the axis of tapering of the body, and
an elongated sacrificial member carried by the hollow chamber. It
is to be understood that the term castable refractory is a uniform
mixture, but uniform does not require complete homogeneity of
material and includes the intermixture of shot, steel fiber or
other materials which may be consistently mixed with a castable
refractory material to adjust the specific gravity of the body. In
any event, the specific gravity of the uniform mixture is selected
so that the body and sacrificial member combination is buoyantly
supported at the interface of the slag layer and the molten metal
layer. Moreover, the vortex inhibitor of the present invention does
not require assembly before shipping, thus reducing the difficulty
and cost associated with shipping previously known bodies with
guides.
[0012] The body has a generally tapering shape along a longitudinal
axis from a base toward a narrow end. The term generally tapering
means that the body generally conforms with the shape of the vortex
formed by the swirling molten metal above the discharge nozzle. The
cross-sectional area of the base is greater than that of the narrow
end. As used herein, the term narrow end is to be understood as not
defining any particular shape, and may include a pointed end, a
rounded end or a flat surface. The base can be formed from a simple
or complex polygon, or a rounded or circular figure. Complex
polygonal bases may include flats, recesses or notches. These
features may extend lengthwise along the body. The taper is
preferably consistent along the length of the body. The refractory
body is preferably constructed by creating a mold of the generally
tapering shape.
[0013] The hollow chamber is positioned longitudinally to the
longitudinal axis of the body and extends within the body. The mold
used to construct the refractory body has an insert, preferably in
the form of a shaft which forms the hollow chamber during the
curing process. Depending on the application, the shaft may be
separated from the refractory body or retained within the
refractory body once the molded mixture cures. If the shaft is
separated from the refractory body, the resulting empty hollow
chamber snugly receives the elongated sacrificial member. If the
shaft is retained after construction, the sacrificial member is
attached to an end of the shaft. In either event, when introduced
into the molten metal receptacle, the hollow chamber may fill with
molten metal that forms a core within the refractory body. The
metal core helps orient the refractory body in a narrow end
downward position.
[0014] The sacrificial elongated member may be constructed of
hollow or solid metal and can be coated with a refractory material.
If the elongated member is hollow, then the hollow can be filled
with refractory material, as well. When the vortex inhibitor is
placed in a molten metal receptacle, the sacrificial member can
align the vortex inhibitor with the area in which the vortex would
be likely to form. As the pouring process continues, the
sacrificial member can dissolve into the molten metal bath, and
thereby does not interfere with the flow of molten metal through
the discharge nozzle.
[0015] Thus, the present invention provides a vortex inhibitor
having a refractory body, a hollow chamber within the refractory
body and a sacrificial member. These features help orient the
refractory body so that its narrow end extends downwardly toward
the discharge nozzle of a molten metal receptacle while not
reducing the flow of molten metal through the discharge nozzle.
When inserted into a molten metal bath, the resulting body and
sacrificial member combination has a specific gravity less than the
specific gravity of the molten metal. Preferably, the refractory
body maintains a center of gravity closer to the narrow end than a
center of buoyant support even when the rod has dissolved.
Additionally, since the elongated member is sacrificial, it can
dissolve before creating a throttling effect upon the discharge
flow.
[0016] As a result, the present invention permits substantially
complete drainage of the furnace with minimal intermixture of the
slag and molten metal layers. Moreover, it will be understood that
the present invention can also be used for other molten metal
receptacles, such as ladles and tundishes, in which separation of
the slag from molten metal must be maintained while the metal is
discharged from the receptacle.
BRIEF DESCRIPTION OF DRAWINGS
[0017] The present invention will be more clearly understood by
reference to the following detailed description of the embodiments
of the present invention when read in conjunction with the
accompanying drawings in which like reference characters refer to
like parts throughout the views and in which:
[0018] FIG. 1 is an elevational view of a molten metal receptacle
containing a vortex inhibitor constructed in accordance with the
present invention;
[0019] FIG. 2 is a perspective view of the vortex inhibitor shown
in FIG. 1;
[0020] FIG. 3 is a sectional view taken substantially along the
line 3-3 in FIG. 2;
[0021] FIG. 4 is a sectional view of an embodiment of a vortex
inhibitor constructed in accordance with the present invention;
[0022] FIG. 5 is a sectional view of a further embodiment of a
vortex inhibitor constructed in accordance with the present
invention;
[0023] FIG. 6 is a sectional view of yet another embodiment of a
vortex inhibitor constructed in accordance with the present
invention;
[0024] FIG. 7 is a sectional view of a further embodiment of a
vortex inhibitor constructed in accordance with the present
invention.
[0025] FIG. 8 is a top plan view of a modified refractory body
constructed in accordance with the present invention;
[0026] FIG. 9 is a sectional view taken substantially along the
line 9-9 in FIG. 8;
[0027] FIG. 10 is a top plan view of another modified refractory
body constructed in accordance with the present invention;
[0028] FIG. 11 is a sectional view taken substantially along the
line 11-11 in FIG. 10;
[0029] FIG. 12 is a top plan view of a further modification of a
refractory body constructed in accordance with the present
invention;
[0030] FIG. 13 is a sectional view taken substantially along the
line 13-13 in FIG. 12;
[0031] FIG. 14 is a top plan view of another modified refractory
body constructed in accordance with the present invention;
[0032] FIG. 15 is a sectional view taken substantially along the
line 15-15 in FIG. 14;
[0033] FIG. 16 is a top plan view of yet another modified
refractory body constructed in accordance with the present
invention; and
[0034] FIG. 17 is a perspective view of the body shown in FIG.
16.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0035] Referring first to FIG. 1, a molten metal receptacle 10 is
shown having a bottom wall 12 with a discharge nozzle 14 and nozzle
opening 16. The molten metal receptacle 10 can be a furnace, ladle,
reservoir, tundish or other receptacle from which molten metal is
discharged through a nozzle 14. Regardless of the type of
receptacle, the receptacle 10 is shown containing a layer of molten
metal 18. A layer of slag 20, having a specific gravity less than
the specific gravity of the molten metal 18, rests on top of the
layer of molten metal 18. A vortex inhibitor 22 according to the
present invention is shown supported at the interface of the slag
layer 20 and the molten metal layer 18 within the receptacle
10.
[0036] Referring now to FIGS. 2 and 3, the vortex inhibitor 22
comprises a body 24 having a base 26 and narrow end 28, a hollow
chamber 30 and an elongated sacrificial member 32. As depicted by
the upward arrows in FIGS. 2 and 3, the sacrificial member 32
slides into the hollow chamber 30 to form an integral vortex
inhibitor. Alternatively, the refractory body 24 can be molded
around the sacrificial member 32. The sacrificial member 32 may be
modified with crimps 25 or protrusions 27, which mount the
sacrificial member 32 in the hollow chamber 30 once the refractory
body 24 cures.
[0037] The outermost points of the base intersect a circle 33
circumscribed about the base. The diameter of the circle 33 is
larger than the diameter of the nozzle opening 16 so that only a
portion of the body may become lodged within the nozzle. Due to the
harsh environmental conditions within the furnace, the diameter of
the circle may be substantially larger than the diameter of the
nozzle opening 16 so that erosion of the body does not reduce the
maximum diameter of the outermost points of the base to less than
the diameter of the nozzle opening.
[0038] The body 24 generally tapers downwardly from the base 26
towards the narrow end 28. The resulting generally tapering shape
is substantially regular so that cross-sectional shapes sliced
downwardly from and perpendicularly to the base 26 towards the
narrow end 28 are substantially congruent. However, some variation
in the cross-sectional shapes can be accommodated.
[0039] When the body 24 and the sacrificial member 32 combination
is supported at the interface of the slag layer 20 and the molten
metal layer 18, the combination is self-orienting in a narrow end
downward position. In the present embodiment, this orientation can
be aided by the hollow chamber 30 and the sacrificial member 32.
Specifically, after the vortex inhibitor 22 is dropped into the
molten metal receptacle 10, the hollow chamber 30 can fill with
molten metal that forms a core. The core acts to stabilize the
position of the vortex inhibitor 22 in the molten metal so that the
narrow end 28 points downwardly when the vortex inhibitor floats at
the slag-metal interface. Additionally, the sacrificial member 32
may enter the discharge nozzle 14 for a limited time before
dissipating. During this initial period before dissipation, the
sacrificial member steadies the vortex inhibitor 22 in a narrow end
28 downward position. Moreover, the sacrificial member 32 can
initially align the vortex inhibitor 22 with the area in which the
vortex would be likely to form. Even if the sacrificial rod
dissolves, the refractory body maintains a center of gravity 29
closer to the narrow end than a center of buoyant support 31.
[0040] The sacrificial member 32 is preferably a metal pipe, rod or
bar. The length and width of the sacrificial member can be varied
greatly as long as the resulting vortex inhibitor construction has
a specific gravity less than the specific gravity of the molten
metal and is self-orienting in a narrow end downward position when
supported in molten metal. A refractory coating 34 is optionally
attached to the surface of the sacrificial member 32. If the
sacrificial member is hollow, a refractory coating or core 35 may
be included within the hollow sacrificial member. Depending on the
operating conditions of the molten metal receptacle, an interior or
exterior refractory coating may prolong the life of the sacrificial
rod 32. The sacrificial nature of the elongated member does not
impinge on the flow of molten metal through the discharge nozzle
14.
[0041] Referring now to FIG. 4, the vortex inhibitor 36 is shown
with modifications 37 to the hollow chamber 30 and modifications of
the system of attaching the elongated sacrificial member 38 to the
refractory body 40. In the embodiment shown, a hollow shaft 42 is
snugly positioned in the hollow chamber 30, for example, by using
the sleeve as the mold insert during pouring of the refractory
material. The shaft 42 extends beyond the base 44 of the vortex
inhibitor 36. The exposed portion 46 of the hollow shaft 42
contains a notch 45 adaptable for receiving a locating arm (not
shown). The locating arm is responsible for positioning the vortex
inhibitor 36 over the area in which the vortex would be likely to
form and selectively dropping the vortex inhibitor into the molten
metal receptacle. In the embodiment shown, the sacrificial member
38 is attached to the hollow shaft 42 by the use of a nipple 48,
which contains external screw threads 50 on both ends. The nipple
48 mates with the hollow shaft 42, which has internal screw threads
52, and mates with an end of the sacrificial member 38, which
contains internal screw threads 54.
[0042] Referring now to FIG. 5, the vortex inhibitor 56 is shown
with a further modification to the system of attaching the
sacrificial member 58 to the hollow shaft 60. The sacrificial
member 58 connects to the hollow shaft 60 through screw threading
although other connectors may also be used. External screw threads
62 contained on an end of the sacrificial elongated member mates
with internal screw threads 64 on the hollow shaft 60. As with the
embodiment shown in FIG. 4, the hollow shaft 60 has an exposed
portion 66 which may contain a notch 68 for receiving a locating
arm (not shown).
[0043] Referring now to FIG. 6, the vortex inhibitor 70 is shown
with modifications 72 to the hollow chamber 30 and modifications as
shown at 74 and 76 to the system of attaching the elongated
sacrificial member to the refractory body. In the embodiment shown,
a solid shaft 78 is snugly positioned in the hollow chamber 30 and
extends beyond the base 80 and narrow end 82 of the vortex
inhibitor 70. The portion 84 extending beyond the base 82 of solid
shaft 78 contains a bore 86 adaptable for receiving a locating arm
(not shown). The locating arm is responsible for positioning the
vortex inhibitor 70 over the area in which the vortex would be
likely to form and selectively dropping the vortex inhibitor into
the molten metal receptacle. In the embodiment shown, the portion
88 extending beyond the narrow end 82 of solid shaft 78 contains
external screw threads 91. Likewise, an end of sacrificial member
74 contains external screw threads 90, although other connectors
may be used. A coupling 92 mates the solid shaft 78, which has
external screw threads 91, with the end of the sacrificial member
74 containing external screw threads 90, thus forming an integral
refractory body and sacrificial member combination.
[0044] Referring now to FIG. 7, the vortex inhibitor 94 is shown
with further modifications 96 to the hollow chamber 30 and
modifications 97 to the system of attaching the elongated
sacrificial member to the refractory body. In the embodiment shown,
a solid shaft 98 is snugly positioned in the hollow chamber 30 and
extends both beyond the base 100 and the narrow end 102 of the
vortex inhibitor 94. Alternatively, the solid shaft 98 may only
extend beyond the narrow end 102 of the vortex inhibitor 94, thus
forming a bolt 101. The portion 104 extending beyond the base 100
of solid shaft 98 contains a bore 106 adaptable for receiving a
locating arm (not shown). If the bolt 101 is utilized, the base 100
can be fitted with a hook (not shown) adaptable for receiving the
locating arm (not shown). The locating arm is responsible for
positioning the vortex inhibitor 94 over the area in which the
vortex would be likely to form and selectively dropping the vortex
inhibitor into the molten metal receptacle.
[0045] In the embodiment shown, the portion 108 of solid shaft 98
or bolt 101 extending beyond the narrow end 102 is of suitable
diameter to snugly receive the hollow sacrificial member 97. This
snug fit may be achieved by varying the diameter of the extending
portion 108 or creating gripping surface features, for example
protrusions 109, on the surface of the extending portion 108.
However the snug fit is accomplished, the result is an integral
refractory body and sacrificial rod combination.
[0046] Regardless of the method by which the sacrificial member is
joined with the shaft, the specific gravity of the vortex inhibitor
supports it at the interface of the slag layer 20 and the molten
metal 18. Further, regardless of the joining method, the outside
surface of the sacrificial member may be coated with refractory
material. Additionally, the inside surface of a hollow sacrificial
member may be coated with refractory material.
[0047] Referring now to FIGS. 8 and 9, the vortex inhibitor is
shown with a modified body 110 having an octagonal base 112 and
flat sides 114. As with the embodiment shown in FIG. 2, the
vertices 116 of the octagonal base intersect a circle 118
circumscribed about the base and having a diameter dimensioned to
exceed the diameter of the nozzle opening 14. In addition, the body
110 tapers downwardly toward a narrow end 120 in a substantially
regular manner.
[0048] FIGS. 10 and 11 show a further modification of a generally
tapering body 122 of vortex inhibitor. As shown in the drawings, a
body 122 has a substantially circular base 124. However, unlike the
flat sides of the bodies 24 and 110 shown in FIGS. 2 and 8
respectively, surfaces for enhancing fluid contact that inhibiting
the vortex are formed by recesses 126 extending along the sides of
the refractory body 122.
[0049] The embodiment as shown in FIGS. 12 and 13 is similar to
FIG. 10 but vortex inhibiting is enhanced by projections extending
outwardly from the periphery of a substantially conical body 128.
Like the recesses 126 shown in the body 122, a projection 130 can
be tapered from the base 134 toward the narrow end 132, preferably
tapering. Alternatively, like the recesses 126 in the body 122, the
projections 130 extends from the base 134 to the narrow end 132 as
shown in phantom line at 136. Moreover, while the recesses 126 or
the projections 130 are most effective when extending along the
entire length from the base to the narrow end, it may be understood
that such projections and recesses may be truncated short of the
entire length of the body as shown in phantom line at 138.
Variations in the width and the depth of the projections or
recesses are also possible, as indicated by the constant height
projections illustrated in phantom line at 140 in FIG. 13. In
addition, a combination of vortex inhibiting surfaces, for example,
a combination of recesses and projections, can also be employed as
desired without departing from the scope of the present invention.
As a further example, flat sided recesses 142 are shown in phantom
line at 142 in FIG. 12.
[0050] While the previously described embodiments have a base with
a simple geometrical shape, it is also to be understood that
complex geometrical shapes can also be employed in producing the
vortex inhibitor according to the present invention. FIGS. 14 and
15 disclose a refractory body 144 having a complex polygonal base
146. In particular, the base 146 combines a plurality of simple
polygonal shapes emanating outwardly from the center of the body
144. The intersection of the rectangular polygons 148 form planar
surfaces 150 and 152 which intersect in a "V" and inhibit vortex
action, while the depth of the V-shaped recesses control the
throttling effect once the body penetrates the nozzle opening
14.
[0051] As shown in FIGS. 16 and 17, a substantially spherical body
154 can be modified to include vortex inhibiting surfaces by
cutting regular recesses in the spherical structure. The
modification shown in FIGS. 16 and 17 is formed by truncating the
sphere at the intersections of a regular tetrahedron and the
sphere, although other truncations or protrusions may be added. The
flat sides 156 taper downwardly toward the apex 28.
[0052] All of the previously described modifications to the shape
of the refractory body have common characteristics. All of the
shapes provide inertia against the swirling motion of molten metal
above the discharge nozzle 14. Additionally, the shape of the
refractory body inhibits the formation of vortex suction, a
phenomena responsible for drawing slag impurities into the molten
metal poured through the nozzle. Nevertheless, the sacrificial rod
adds additional control and stability without inhibiting the
discharge of molten metal. It is also understood that any of the
previously described refractory body shapes may be combined with
any of the previously described mounts or methods of joining the
sacrificial member with the refractory body in order to form an
integral refractory body and sacrificial rod combination.
[0053] Having thus described the present invention, many
modifications thereto will become apparent to those skilled in the
art to which it pertains without departing from the scope and
spirit of the present invention as defined in the appended
claims.
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