Note: Descriptions are shown in the official language in which they were submitted.
CA 02714682 2010-09-10
MOLTEN ALUMINUM REFINING AND
GAS DISPERSION SYSTEM
CROSS REFERENCE TO RELATED APPLICATION
This application does not claim priority from any other application.
TECHNICAL FIELD
This invention relates to a molten aluminum refining system, more
particularly a rotor based system for injecting gas or gas, flux and/or other
material into molten aluminum.
BACKGROUND OF THE INVENTION
In the processing of molten aluminum, it is desirable to remove certain
gases and other material or elements from the molten aluminum before further
processing, and depending upon the specific application or process. The
equipment or function may generally be referred to as a degasser or degassing.
In a typical application of a degasser for molten aluminum, dissolved
hydrogen from any one or more of multiple potential sources, is a targeted gas
to be removed from the melt prior to the next step in the process (such as
casting for instance). If for instance hydrogen remains in the aluminum during
casting, hydrogen coming out of solution may cause any one or more of cast
problems, such as twisting, flaking, blisters or even cracking. It is
typically
desirable to remove the dissolved hydrogen just prior to the next step in the
process.
The particular dissolved hydrogen content in a given application may vary
substantially, but can range from 0.20 ml/l00g Al for general extrusion billet
down to 0.10 ml/100g Al for rolling slab for aerospace types of applications.
Typically hydrogen is removed from the molten aluminum by introducing
or bubbling an inert gas through the metal. Examples of inert gases which may
be utilized include argon or nitrogen.
In addition to the removal of the hydrogen through the utilization of inert
gases, it is also typical to desire to remove other impurities and/or
inclusions
during the refining process, and this removal may also occur or be desired
during this degassing process. For instance, the addition of smaller amounts
of
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chlorine in the inert gas may remove different inclusions and alkali metal
impurities in a relatively efficient way. Inclusions in molten aluminum may
come from any one or more different sources during the smelting operation, in
the molten metal furnace or from intentionally added material such as grain
refiners. The failure to adequately remove inclusions may result in tears and
surface defects in rolling sheet aluminum, pinholes and increased die wear
during extrusion. It is typical in some applications to target the removal of
approximately 50% of non-wetted inclusions in the degassing system. Later
filtering of the molten aluminum downstream from the degassing system would
typically be utilized to further reduce inclusions in the molten metal.
A typical degasser system, or molten aluminum refining system for the
removal of gases which utilizes a rotor within a stator, would typically
involve
the injection of an inert gas utilizing one or more injectors or injection
devices,
such as a spinning rotor device. The injector would typically introduce the
inert
gas, such as Argon, into the molten metal through numerous bubbles that the
injector may shear and disperse into the molten metal in order to saturate the
molten metal with the inert gas. In systems which do not use a stator, gases
may
be injected through the center of the rotating rotor shaft - however in many
applications it is desired or preferred to utilize a stator for process and
other
reasons.
The inert gas is typically introduced into the molten metal near the bottom
of the containment vessel and the bubbles of gas are dispersed and allowed to
rise to the melt surface, desorbing the dissolved hydrogen in the process. The
addition of chlorine as mentioned above in small amounts (such as 0.5% or
less)
may assist in breaking the bond between the molten aluminum and any non-
wetted inclusions in the molten aluminum, thereby allowing the inclusions to
more readily attach to the rising gas bubbles and be buoyed or lifted to the
melt
surface of the molten aluminum. Additional amounts of chlorine may be added
to the inert gas to chemically react with incoming alkali metals such as
sodium,
lithium, calcium, or others, to form chloride salts that also float to the
surface or
melt surface of the molten aluminum.
Typically the inclusions and solid salts and other material that float to the
melt surface form what is referred to as dross, which can then be skimmed from
the surface and removed as waste.
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It is typically desirable to maximize the saturation of the molten
aluminum with small gas bubbles and to maintain a flat or calm melt surface to
better facilitate the floating and capturing of inclusions and salts to the
melt
surface. Achieving these objectives will generally result in better separation
of
the molten aluminum from the dross. There are many factors that contribute to
the efficiency of these systems, such as the nozzle or injector design, gas
flow
rates, the flatness of the molten aluminum melt surface, vessel chambered
geometries, and others.
Some prior art injectors utilize a spinning rotor within a static stator to
strive toward the desired saturation level, with the spinning rotor being
attached
or integral with a nozzle portion. The spinning rotor may actually be used to
shear and help disperse the gas bubbles and any additions thereto, into the
molten aluminum. It is also desirable, in order to maintain the melt surface
relatively still or flat, to avoid a vortex effect from the rotation of the
rotor. A
vortex affect would tend to cause disruptions in the surface, a partially
mixing
or dispersion of the material in the dross with the molten aluminum, and
generally interfere with or hinder the removal of undesirable gas and
inclusions.
One example of a molten aluminum degassing or metal refining system is
one offered by Pyrotek under the SNIF trademark. References and information
relative to the Pyrotek products may be found at its website at www.pyrotek-
inc.com.
Prior United States patents referring to such prior art systems, include the
following: U.S. Patent No. 5,198,180, for a Gas Dispersion Apparatus with a
Rotor and Stator for Molten Aluminum Refining; U.S. Patent No. 5,846,481, for
a Molten Aluminum Refining Apparatus; U.S. Patent No. 3, 743, 263, for an
Apparatus for Refining Molten Aluminum; and U.S. Patent No. 4,203,581, for
an Apparatus for Refining Molten Aluminum; all of which are hereby
incorporated in their entirety by this reference as those set forth fully
herein.
In a typical prior art configuration for molten aluminum refining, one or
more injectors such as injector 130 in Figure 2, would be located within the
molten aluminum or molten metal, and the gases would be introduced through
that injector as described below.
It is also desirable to reduce the dissolved gas content and the non-
metallic in purity content of the molten aluminum, and this is typically
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accomplished by utilizing any one or more of various fluxing processes, which
is where the molten metal is contacted with either reactive gaseous or solid
fluxing agents (such as halogens). Chlorine gas for instance may be utilized
in
the removal of the non-metallic impurities. If it is desired in a given
application
to also introduce flux into the molten aluminum, a separate piece of
equipment,
namely a device such as a flux injector, is introduced into the molten metal
and
flux is thereby delivered or injected into the molten aluminum. This requires
an
additional expense, additional capital outlay for the machinery, and
additional
maintenance thereon.
It is therefore an objective of embodiments of this invention to provide a
molten aluminum refining system which will allow for the injection of gas and
flux while utilizing a spinning rotor within a static stator.
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BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are described below with
reference to the following accompanying drawings.
Figure 1 is an elevation view of one embodiment of a molten
aluminum refining system contemplated by this invention;
Figure 2 is a perspective cutaway view of a prior art molten metal
refining system;
Figure 3 is a perspective cutaway view of one embodiment of a
molten metal refining system contemplated by this invention;
Figure 4 is a perspective view of another embodiment of a molten
metal refining system contemplated by this invention with a
differently configured spinning rotor;
Figure 5 is a top view of the rotor illustrated in Figure 3;
Figure 6 is section 6 - 6 from Figure 5;
Figure 7 is a top view of the rotor illustrated in Figure 4;
Figure 8 is section 8 - 8 from Figure 7;
Figure 9 is a top view of another embodiment of a rotor which may be
utilized in embodiments of this invention;
Figure 10 is section 10-10 from Figure 9;
Figure 11 is an elevation view of another embodiment of a molten
aluminum refining system contemplated by this invention;
Figure 12 is a top view of another embodiment of a rotor which may be
utilized in embodiments of this invention; and
Figure 13 is section 13-13 from Figure 12.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Many of the fastening, connection, manufacturing, and other means and
components utilized in this invention are widely known and used in the field
of
the invention described, and their exact nature or type is not necessary for
an
understanding and use of the invention by a person skilled in the art or
science;
therefore, they will not be discussed in significant detail. Furthermore, the
various components shown or described herein for any specific application of
this invention can be varied or altered as anticipated by this invention. The
practice of a specific application or embodiment of any element may already be
widely known or used in the art or by persons skilled in the art or science
and
therefore each will not be discussed in significant detail.
The terms "a", "an", and "the" as used in the claims herein are used in
conformance with long-standing claim drafting practice and not in a limiting
way. Unless specifically set forth herein, the terms "a", "an", and "the" are
not
limited to one of such elements, but instead mean "at least one".
Figure 1 is an elevation view of one embodiment of a molten aluminum
refining system 100 contemplated by this invention, such as a containment or
refining vessel 101, illustrating two injectors 102, refractory lining 103,
stators
106 within vessel compartments 104 and 105 (which may also be referred to as
refining chambers individually or collectively), molten metal level 107, such
as
molten aluminum. The two spinning rotors 108 are spinning as indicated by
arrows 109 and gas bubbles including flux 113 are being dispersed from a
central passageway or central passageway, and gas bubbles 111 which do not
contain flux are being dispersed from between the stators 106 and the rotor
110.
Figure 2 is a perspective cutaway view of a prior art molten metal
refining system 130, or injector 130, illustrating rotor shaft 131, stator
132,
spinning rotor 133 attached to rotor shaft 131, with arrow 137 illustrating
the
rotation of spinning rotor 133. Spinning rotor 133 includes a plurality of
blades
134 (or vanes) with space 135 there between.
Figure 2 illustrates an example of prior art gas introduction or injection
through the metal refining system, with gas arrow 144 illustrating the flow
between stator 132 and rotor shaft 131. The gas then enters passageways 140
within rotor shaft 131, with passageways 140 being a portion thereof, and
exits
in the gap between the spinning rotor 133 portion (may also be referred to as
a
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spinning nozzle) of the rotor shaft 131 and the stator 132 as indicated by
arrows
136 and 140. Primary passageway 139 may include one or more inlets for the
gas in one or more gas outlets 140, showing gas 142 exiting the same.
As can also be seen from Figure 2, the rotor shaft 131 is rotatably
positioned within the internal cavity within stator 132 such that it may be
driven
by a motor or other drive within the stator 132 cavity. The rotor shaft 131 is
operably attached to the spinning rotor 133 such that the nozzle rotates with
the
rotor shaft 131. A gas passageway is also provided between the internal cavity
surface of the stator 132 and the outer surface of the rotor shaft 131 such
that
gases 144 may pass through the passageway before being discharged between
the bottom of the stator 132 and the top of the spinning rotor 133.
Figure 2 also illustrates where the outer surface of the rotor shaft 131
interacts with the interior surface of the stator 132, with that intersection
identified as item 129, which may also be referred to as gap 129. The area of
that intersection may be referred to as a bushing, a bearings or using other
terms, and there may in some embodiments be a two to four one-thousandths of
an inch clearance between the two components. It is typically desirable to
maintain a certain pressure of gas below that gap 129 so that molten metal
does
not enter the gap 129 at the lower end near the rotating rotor 133.
The gas from both passageways is discharged and preferably sheared
between the top of the spinning rotor 133 and the bottom of the stator 132,
and
the vanes 134 of the spinning rotor 133 contribute to the sheering of the gas
bubbles 147 and dispersion thereof within the molten metal surrounding the
spinning rotor 133. In typical applications utilizing the gap 129, only gas is
utilized in connection with the stator 132 and rotor configuration.
Figure 2 illustrates gas bubbles 147 exiting and then dispersed throughout
the molten metal in which the injector 130 is operating. The gas bubbles 147
exiting the injector 130 are more buoyant than the molten aluminum and
therefore float upwards towards the surface of the molten aluminum, the melt
surface.
In the prior art example illustrated in Figure 2, there is no real provision
for the introduction of flux into the molten aluminum where the gas bubbles
147
are released. In a typical prior art system, there would be a separate flux
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injector that would be moved into the molten metal and through which flux
would be injected.
Figure 3 is a perspective cutaway view of one embodiment of a molten
metal refining system 160 contemplated by this invention. Figure 3 illustrates
an injector which in this embodiment includes stator 162, rotor shaft 161,
passageway between the stator 162 and the rotor shaft 161 through which gas
164 is passed in the manner illustrated in the prior art example shown in
Figure
2. Spinning rotor 167 includes blades 170 (or vanes) with space or distance
171
there-between. Gas bubbles 177 which include gases are released as indicated
by arrows 169 and 173 into the molten aluminum for dispersion.
Figure 3 also illustrates a central passageway 166 (or conduit) through
which gas and flux are introduced as indicated by arrow 163 from an external
source 178, which is being injected or pumped into central passageway 166.
Figure 3 also shows gas passageway 159 between stator 162 and rotor shaft 161,
and through which gas is introduced into the injector 160 or molten metal
refining system (preferably molten aluminum). While typically flux may be
provided in powder or other solid form and mixed with gas to inject it into
the
molten metal, there may also be applications such as future applications
wherein
a flux in liquid or gaseous form is utilized.
It will be appreciated by those of ordinary skill in the art that while the
term "center" is used to describe the central passageway through the internal
part of the rotor shaft, the passageway does not need to be right on the
center
axis, but instead may be offset there-from but still within the rotor shaft,
all
within the contemplation of this invention. In the event the central
passageway
is not exactly on the center axis, the rotor or rotor shaft may need to be
balanced
in order to reduce or eliminate vibration.
It will be appreciated by those of ordinary skill in the art that any one of a
number of different spinning rotors may be utilized with no one in particular
being required to practice this invention, all within the contemplation of
this
invention and depending upon the specific application of the embodiment of
this
invention being practiced. For example, another exemplary spinning rotor is
illustrated in Figure 4 as spinning rotor 192.
As can also be seen from Figure 3, the rotor shaft 161 is rotatably
positioned within the internal cavity within stator 162 such that it may be
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driving by a motor or other drive within the stator 162 cavity. The rotor
shaft
161 is operably attached to the spinning rotor 167 such that the nozzle
rotates
with the rotor shaft 161. A gas passageway is also provided between the
internal
cavity surface of the stator 162 and the outer surface of the rotor shaft 161
such
that gasses 164 may pass through the passageway before being discharged
between the bottom of the stator 162 and the top of the spinning rotor 167.
The
gas is discharged and preferably sheared between the top of the spinning rotor
167 and the bottom of the stator 162, and the vanes 170 of the spinning rotor
167 contribute to the sheering of the gas bubbles 177 and dispersion thereof
within the molten metal surrounding the spinning rotor 167. The stator 162 may
be smooth, include vanes 170, or include any one of a number of different
surfaces and configurations on the outer surface thereof, with no one in
particular being required to practice this invention.
Figure 3 also illustrates where the outer surface of the rotor shaft 161
interacts with the interior surface of the stator 162, with that intersection
identified as item 179, which may also be referred to as gap 179. The area of
that intersection 179 may be referred to as a bushing, a bearing, or using
other
terms, and there may in some embodiments be a two to four one-thousandths of
an inch clearance between the two components. It is typically desirable to
maintain a certain pressure of gas in that gap 179 so that molten metal does
not
enter the gap 179 at the lower end near the rotating rotor 167. It is
typically
desirable to maintain a certain pressure of gas below that gap 179 so that
molten
metal does not enter the gap 179 at the lower end near the rotating rotor 167.
In typical applications utilizing the gap 179, only gas is utilized in
connection with the stator and rotor configuration, with any desired flux
being
added through a separate injector. However, embodiments of this invention,
may provide for the introduction of flux in molten metal processing systems
which utilize a rotating rotor and shaft within a stator.
Figure 4 is a perspective view of another embodiment of a molten metal
refining system 190 contemplated by this invention with a differently
configured
spinning rotor 192. Figure 4 illustrates injector 190, stator 191, rotor shaft
203,
spinning rotor 192, with blades 193, including space 194 between respective
blades 193 or vanes, and lower portion 195 of spinning rotor 192 which has a
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continuous circumference. Gas bubbles 207 are disbursed from between the
stator 191 and the spinning rotor 192.
Figure 4 further illustrates a source of gas and flux 197, or a source of gas
199 alone, which may be pumped or injected into central passageway 204. The
source of gas 199 may provide gas both to the central passageway 204 and/or to
the more traditional gas passageways (as shown in Figure 3 as passageway 159).
Figure 4 also shows gas bubbles 202 which includes flux being dispersed
from underneath the spinning rotor 192 and which originated in central
passageway 204. Depending upon the specific flux material or materials
utilized, the gas and solid flux material, or gas alone, may be the sole
injection
into the central passageway 204, or it may be combined with gases or other
desired additions, all in the contemplation of this invention and with no one
in
particular being required to practice this invention.
As will be appreciated by those of ordinary skill in the art, the gas and
flux flow rates will depend on the metal flow rate, the impurities in the
incoming metal in a given application, and the desired quality of the output
metal. However, in one example the gas may range flow up to five cfm (eight
Nm3/h), with a typical range being in the two to four and one-half cfm (three
to
seven Nm3/h). The flux material in typical application may utilize up to
twenty
g/m or higher. The flow rates given herein are per nozzle and are given as
examples and not to limit the invention in any way as it is not dependent on
any
particular range or set of parameters in the metal processing system.
While the preferred gas used in combination with this invention in a given
embodiment is argon, nitrogen, or others may also be utilized. Although this
invention is not limited to any particular flux material, a preferred flux
material
in a given embodiment may be a eutectic mixture of magnesium chloride and
potassium chloride (which is commonly known by trademarks ProMag and
Zendox).
Figure 5 is a top view of the spinning rotor 210 illustrated in Figure 3,
illustrating center or central passageway 221 in spinning rotor 210 with
blades
211, top surface 210b, slots 212 between respective or adjacent blades 211.
It will be appreciated by those of ordinary skill in the art that the spinning
rotor 210 maybe one piece with the rotor shaft and considered part of the
rotor
shaft with which it rotates, or it may be a two piece configuration attached
to the
CA 02714682 2010-09-10
rotor shaft, all within the contemplation of this invention and depending upon
the specific application of the invention.
It would be typical to make the stator, rotor and spinning rotor out of a
graphite or other similar material, although no one particular material or
materials is required to practice this invention. It will also be appreciated
by
those of ordinary skill in the art that while a couple preferred examples of
rotors
and stators are shown, no one particular configuration is required to practice
this
invention.
Figure 6 is section 6 - 6 from Figure 5, and illustrates central passageway
221 within spinning rotor 210.
Figure 7 is a top view of the spinning rotor 250 illustrated in Figure 4,
showing a plurality of apertures 252 between blades 251, with central
passageway 256 and top surface 250b of spinning rotor 250.
Figure 8 is section 8 - 8 from Figure 7, and illustrates central passageway
256 within spinning rotor 250.
Figure 9 is a top view of another embodiment of a rotor 280 which may be
utilized in embodiments of this invention. Figure 9 illustrates a spinning or
rotating rotor 280, a plurality of apertures 282 in the rotor 280, a plurality
of
blades 281, which may also be referred to as vanes or fins. The rotor 280 is
configured with the apertures 282 to provide a controlled upward flow of
molten
metal through the apertures 282. The rotor 280 in this embodiment has an
extended bottom portion, or ring, which extends beyond the outer edge 281a of
the blades 281 by distance 286,.with the outer edge 280a of the rotor 280
shown
outwardly from the outer edge 281a of the blades 281. Slots 277 are shown
between adjacent blades 281. The ring extending the periphery of the bottom
portion fo the rotor 280, may allow a more stable and more complete bubble
distribution at a slower speed. Apertures 282 may also be provided with a
larger
area to allow more molten metal flow there-through as compared to the rotor
design illustrated in Figure 7 for example.
It will be appreciated by those of ordinary skill in the art that no one
particular size or dimensions are required to utilize the ring feature in
different
embodiments of this invention. A ring distance may for example be configured
in the one-half to three-quarter inch range for distance 286. Utilizing a ring
in
embodiments of this invention may also allow for the blades 281 to be deeper
or
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longer in the vertical direction with larger apertures 282 to increase the
metal
flow and better allow a slower rotational speed of the rotor 280. Those in the
art will also appreciate that larger apertures 282 will reduce the blockages
or
blockage potential of the apertures 282.
It is preferable in embodiments of this invention to control the direction
of the metal flow relative to the rotor by adjusting the nozzle speed. At low
speeds for instance, the molten metal will tend to flow upward and be carried
by
the buoyancy of the bubbles. At very high speeds, the metal and bubbles will
be
driven downward towards the bottom of the chamber. At interim speeds, which
may be preferable in embodiments of this invention, the molten metal and
bubbles will move horizontally outward from the rotor. The ring as shown may
at least partially function to restrict the upward metal flow into the rotor,
which
may tend to promote a more stable outward flow from the rotor in a horizontal
or slightly downward direction because the downward metal flow into the rotor
from the top of the rotor is not as restricted.
The ring portion of the rotor 280 combined with the apertures 282, may
be sized and configured to control the upward flow of molten metal into the
rotor 280 to better disperse the gas out the side of the rotor 280. It will be
appreciated by those of ordinary skill in the art that the size and
configuration of
the apertures 282 relative to the ring and the blades 281 may be based on
empirical data from testing to find the best configuration for a particular
application, including for a particular rotational speed, all within the
contemplation of this invention, and with no one in particular being required
to
practice this invention.
Figure 10 is section 10-10 from Figure 9, and illustrates central
passageway 283 within spinning rotor 280.
The embodiment of the rotor 280 illustrated in Figures 9 and 10 may be
utilized in applications where lower speed (revolutions per minute or rpm's)
is
desired. While there are any one of a number of different possibilities for
the
preferred revolutions per minute to run the rotor at for a given application,
the
rotor 280 in Figures 9 and 10 may be run at slower speeds such as one hundred
to two hundred revolutions per minute. While the speed of a rotor in a given
embodiment may typically be up to eight hundred rpm's, the typical nozzle
application will be in the three hundred to seven hundred revolutions per
minute
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range. This invention however is not limited to any particular range or values
of
revolutions per minute or specific process parameters, which may change
depending on the process factors in a given application or embodiment.
It will be appreciated by those of ordinary skill in the art that it may be
preferred in some applications of some embodiments of this invention, to run
the
rotor 280 at a lower rate to maintain a calmer surface level of the molten
metal
and avoid a vortex effect.
Figure 11 is an elevation view of another embodiment of a molten
aluminum refining system 320 contemplated by this invention, such as a
containment or refining vessel 101, illustrating two injectors 102, refractory
lining 103, stators 106 within vessel compartments 104 and 105, molten metal
level 107, such as molten aluminum. The like components in this embodiment
with the embodiment illustrated in Figure 1 are labeled with the same item
numbers for ease of reference and consistency.
This embodiment illustrates two different spinning rotors 280 and 300,
which are as illustrated in Figure 9 and Figure 12 respectively. Each of the
spinning rotors 280 and 300 are spinning as indicated by arrows 109, with
rotor
280 including a central passageway for injecting gas bubbles which may include
flux 113 are being dispersed from a central passageway or central passageway,
and gas bubbles 111 which do not contain flux are being dispersed from between
the stators 106 and the rotor 110. However rotor 300 does not include a
central
passageway (see description below relative to Figures 12 and 13), and
therefore
gas bubbles are not shown in connection therewith. Figure 11 illustrates a
preferred embodiment of a two chamber refining system with a combination of
the two different rotors 280 and 300. It will also be appreciated by those of
ordinary skill in the art that any combination of rotors that are capable of
injecting flux such as rotors 210, 250 and 280, and rotors that do not inject
flux
such as rotors 134 and 300, can be used in a single and multiple chamber
refining systems.
It will also be appreciated by those of ordinary skill in the art that a
similar rotor without the central passageway 283 may be utilized in
applications
where lower speed (revolutions per minute or rpm's) is desired and flux
injection is not required. An example of this rotor is shown as item 300 in
Figure 11, and in Figures 12 and 13.
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Figure 11 also illustrates how apertures in the rotors 280 and 300 may
create an upward flow 114 of molten metal through apertures such as apertures
282 as shown in Figure 9 and Figure 12.
Figure 12 is a top view of an embodiment of a rotor 300 which may be
utilized in embodiments of this invention when flux is not required. Figure 12
illustrates a spinning or rotating rotor 300, a plurality of apertures 302 in
the
rotor 300, a plurality of blades 301, which may also be referred to as vanes
or
fins. The components and items in Figures 12 and 13 which are like items to
those in Figures 9 and 10 are like numbered.
Figure 13 is section 13-13 from Figure 12 and all items are numbered the
same as in Figure 12, and therefore will not be repeated here.
The alternative embodiments of rotors illustrated herein, such as in
Figures 7, 9 and 12, may be utilized in combination with injectors and
provided
with gas or gas and flux as shown and described elsewhere herein, such as in
Figure 4.
As will be appreciated by those of reasonable skill in the art, there are
numerous
embodiments to this invention, and variations of elements and components which
may be
used, all within the scope of this invention.
One embodiment of this invention, for example, is a gas dispersion apparatus
for the
injection of gas and flux into molten metal, comprising: an elongated stator
with an
internal cavity; a rotor including a rotor shaft, wherein the rotor shaft is
rotatably mounted within the internal cavity of the stator; a passageway
between an internal wall of the internal cavity in the stator and an outer
wall of
the rotor shaft to facilitate gas discharge at or near a top of the rotor; and
a
central passageway from a top portion of the rotor shaft extending through to
a
bottom of the rotor, the central passageway providing a passageway for gas and
flux to be discharged at the bottom of the rotor.
In one example of a process embodiment of the invention, a process for
simultaneously dispersing gas and flux into molten aluminum may be provided,
comprising the following: providing an elongated stator with an internal
cavity
providing a rotor including a rotor shaft, wherein the rotor shaft is
rotatably
mounted within the internal cavity of the stator; providing a gas passageway
between an internal wall of the internal cavity in the stator and an outer
wall of
the rotor shaft to facilitate gas discharge at or near a top of the rotor;
providing
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a central passageway from a top portion of the rotor shaft extending through
to a
bottom of the rotor; rotating the rotor within molten aluminum; injecting gas
into the gas passageway such that it is discharged into the molten aluminum
between the rotor and the stator; and injecting gas and flux into the central
passageway such that it is discharged into the molten aluminum at the bottom
of
the rotating rotor.
In yet another embodiment of the invention, a bladed rotor for
incorporation in a spinning nozzle assembly is provided, which is adapted for
the injection of gas into molten aluminum present in a refining chamber during
aluminum refining operations therein, said bladed rotor comprising: a rotor
periphery with an upper periphery which includes alternate blades and slots
around the upper periphery, and with a lower periphery which includes a ring
extending radially beyond the upper periphery; and wherein the ring contains
apertures therein which coincide with the slots and which provide for a
controlled upward passage of molten aluminum therethrough upon use of said
rotor for aluminum refining operations.
