U.S. patent application number 11/928254 was filed with the patent office on 2008-02-28 for electromagnetic pump.
This patent application is currently assigned to INDUCTOTHERM CORP.. Invention is credited to Oleg S. FISHMAN, Vitaly A. PEYSAKHOVICH, Emad TABATABAEI.
Application Number | 20080050247 11/928254 |
Document ID | / |
Family ID | 33310872 |
Filed Date | 2008-02-28 |
United States Patent
Application |
20080050247 |
Kind Code |
A1 |
PEYSAKHOVICH; Vitaly A. ; et
al. |
February 28, 2008 |
Electromagnetic Pump
Abstract
An electromagnetic pump has a supply section and a magnetic
force pumping section wherein flow of an electrically conductive
material through the supply section is opposite to the flow of the
material in the magnetic force pumping section in some examples.
Multiple coils surround the supply and magnetic force pumping
sections. Current flowing through the multiple coils creates
magnetic fields that magnetically couple with a magnetic material
disposed between the supply and magnetic force pumping sections so
that the fields penetrate the electrically conductive material in
the magnetic force pumping section substantially perpendicular to
the desired flow direction which maximizes the magnitudes of
magnetic forces applied to the electrically conductive material.
Alternatively the electromagnetic pump has a supply section and a
magnetic force pumping section wherein flow of an electrically
conductive material through the supply section is in the same
direction as the flow of the material in the magnetic force pumping
section.
Inventors: |
PEYSAKHOVICH; Vitaly A.;
(Moorestown, NJ) ; FISHMAN; Oleg S.; (Maple Glen,
PA) ; TABATABAEI; Emad; (Voorhees, NJ) |
Correspondence
Address: |
PHILIP O. POST;INDEL, INC.
PO BOX 157
RANCOCAS
NJ
08073
US
|
Assignee: |
INDUCTOTHERM CORP.
10 Indel Avenue P.O. Box 157
Rancocas
NJ
08073
|
Family ID: |
33310872 |
Appl. No.: |
11/928254 |
Filed: |
October 30, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10825634 |
Apr 15, 2004 |
7300258 |
|
|
11928254 |
Oct 30, 2007 |
|
|
|
60464317 |
Apr 21, 2003 |
|
|
|
Current U.S.
Class: |
417/50 |
Current CPC
Class: |
F04B 17/00 20130101;
F04B 15/04 20130101; F04B 17/04 20130101 |
Class at
Publication: |
417/050 |
International
Class: |
F04B 15/00 20060101
F04B015/00; F04B 17/00 20060101 F04B017/00 |
Claims
1. An apparatus for pumping an electrically conductive material,
the apparatus comprising: an open outer tube, the opening in the
bottom of the outer tube in communication with an inlet for entry
of the electrically conductive material into the open outer tube;
an open mid tube disposed within the outer tube to form an annular
volume between the inner wall of the outer tube and outer wall of
the mid tube, the mid tube having a closed bottom, the top of the
annular volume in communication with an outlet for exit of the
electrically conductive material from the apparatus; an inner
structural element disposed within the mid tube; a magnetic
material disposed between the outer wall of the inner structural
element and the inner wall of the mid tube; a plurality of
induction coils disposed around the exterior height of the outer
tube; and a means for supplying an ac current to each of the
plurality of induction coils to force the electrically conductive
material up through the annular volume and the outlet by the
magnetic force applied to the electrically conductive material by
the magnetic fields created by the supply of the ac current to each
of the plurality of induction coils.
2. The apparatus of claim 1 wherein each of the plurality of
induction coils comprises a bobbin magnetic coil.
3. The apparatus of claim 1 wherein the means for supplying the ac
current to each of the plurality of induction coils comprises a
power supply having a three phase output wherein each two of the
three phases, with alternating positive and negative phase
orientation, are sequentially connected to the plurality of
induction coils to create a six phase cycle of the magnetic fields
to force the electrically conductive material up through the
annular volume and the outlet.
4. The apparatus of claim 3 wherein each of the plurality of
induction coils comprises a bobbin magnetic coil.
5. The apparatus of claim 3 wherein the power supply has a variable
output voltage or output frequency.
6. The apparatus of claim 1 wherein the means for supplying the ac
current to each of the plurality of induction coils comprises a
power supply having a plurality of three phase outputs wherein each
two of the three phases, with alternating positive and negative
phase orientation, are sequentially connected to the plurality of
induction coils to create a multi-phase cycle of the magnetic
fields to force the electrically conductive material up through the
annular volume and the outlet.
7. The apparatus of claim 6 wherein each of the plurality of
induction coils comprises a bobbin magnetic coil.
8. The apparatus of claim 6 wherein the power supply has a variable
output voltage or output frequency.
9. A method of pumping an electrically conductive material
comprising the steps of: supplying the electrically conductive
material into an opening in the bottom of an open outer tube;
connecting the open bottom of the outer tube with an annular volume
formed between the outer wall of a mid tube and the inner wall of
the outer tube; disposing a magnetic material between the outer
wall of an inner structural element and the inner wall of the mid
tube; surrounding the exterior of the outer tube with a plurality
of induction coils; and applying ac current to each of the
plurality of induction coils to force the electrically conductive
material up through the annular volume and an outlet by the
magnetic force applied to the electrically conductive material by
the magnetic fields created by the ac current in each of the
plurality of induction coils.
10. The method of claim 9 further comprising the step of supply the
ac currents to each of the plurality of induction coils from a
three phase supply wherein each two of the three phases, with
alternating positive and negative phase orientation, are
sequentially connected to the plurality of induction coils.
11. An apparatus for pumping an electrically conductive material,
the apparatus comprising: an open outer tube, the opening in the
bottom of the outer tube in communication with an inlet for entry
of the electrically conductive material into the open outer tube;
an open mid tube disposed within the outer tube to form an annular
volume between the inner wall of the outer tube and outer wall of
the mid tube, the mid tube having a closed bottom, the top of the
annular volume in communication with an outlet for exit of the
electrically conductive material from the apparatus; an inner
structural element disposed within the mid tube; a magnetic
material disposed between the outer wall of the inner structural
element and the inner wall of the mid tube; a plurality of
induction coils disposed around the exterior height of the outer
tube; and a power supply having at least one three phase output
wherein each two of the three phases, with alternating positive and
negative phase orientation, are sequentially connected to the
plurality of induction coils to create a six phase cycle of the
magnetic fields to force the electrically conductive material up
through the annular volume and the outlet.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a divisional application of application Ser. No.
10/825,634, filed Apr. 15, 2004, which application claims the
benefit of U.S. Provisional Application No. 60/464,317, filed Apr.
21, 2003, both of which applications are hereby incorporated herein
by reference in their entireties.
FIELD OF THE INVENTION
[0002] The present invention relates to electromagnetic pumps that
move an electrically conductive fluid by interaction with magnetic
fields.
BACKGROUND OF THE INVENTION
[0003] Electromagnetic pumps can be used to pump electrically
conductive fluids, such as an electrically conductive molten metal
composition. An advantage of an electromagnetic pump is that the
fluid can be magnetically induced to move through a tube or conduit
without the use of mechanical pump components inside of the
conduit.
[0004] Known electromagnetic pumps are either submersed in, or
integrally attached to, the source of the electrically conductive
fluid, such as a metal melting and/or melt holding furnace. These
pump installations are difficult to service and maintain. Therefore
there is the need for an efficient and easily maintainable
electromagnetic pump that is not integrally attached to the source
of the electrically conductive fluid.
BRIEF SUMMARY OF THE INVENTION
[0005] In one aspect, the invention is apparatus for and method of
pumping an electrically conductive material in a pump having a
supply section or volume, and a magnetic force pumping section or
volume. In one example of the invention the directional flow of the
material through the supply section is opposite to the directional
flow of the material through the magnetic force pumping section.
Multiple coils surround the supply and magnetic force pumping
sections. Current flowing through the multiple coils creates
magnetic fields that magnetically couple with a magnetic material
disposed between the supply and magnetic force pumping sections so
that the fields penetrate the electrically conductive material in
the magnetic force pumping section substantially perpendicular to
the desired flow direction. This field orientation maximizes the
magnitudes of the magnetic forces applied to the electrically
conductive material in the magnetic force pumping section.
[0006] These and other aspects of the invention are set forth in
the specification and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The figures, in conjunction with the specification and
claims, illustrate one or more non-limiting modes of practicing the
invention. The invention is not limited to the illustrated layout
and content of the drawings.
[0008] FIG. 1 is a side perspective view of one example of an
electromagnetic pump of the present invention.
[0009] FIG. 2 is a side elevational view of one example of an
electromagnetic pump of the present invention.
[0010] FIG. 3(a) is a side sectional view through line A-A in FIG.
2 of one example of an electromagnetic pump of the present
invention.
[0011] FIG. 3(b) is a top sectional view through line B-B in FIG. 2
of one example of an electromagnetic pump of the present
invention.
[0012] FIG. 3(c) is a partial sectional view of the interface
region for inner, mid and outer tubes, and magnetic material, used
in one example of an electromagnetic pump of the present
invention.
[0013] FIG. 4(a) is a simplified schematic diagram of a power
supply and power distribution to induction coils used with an
electromagnetic pump of the present invention.
[0014] FIG. 4(b) is a vector diagram illustrating one example of
phase distribution of the output of a power supply to the induction
coils used with an electromagnetic pump of the present
invention.
[0015] FIG. 5 is a side sectional view of another example of an
electromagnetic pump of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Referring now to the drawings, wherein like numerals
indicate like elements, there is shown in the figures one example
of electromagnetic pump 10 of the present invention for pumping an
electrically conductive material, such as an electrically
conductive molten metal. In FIG. 1, twelve induction coils (12a
through 12l) as further described below, are surrounded by a
plurality of vertical magnetic shunts 14 held in place by shunt
supports 16, which are attached to base 18 at one end, and to yoke
20 at the opposing end. The base and yoke may optionally be formed
from a magnetic material to provide bottom and top magnetic field
containment. Other shunt and outer support arrangements as known in
the art may be used in lieu of the shunt and support arrangements
shown in FIG. 1. Pump inlet 24 and pump outlet 22 in this
non-limiting example of the invention, are cylindrically formed
from a suitable heat-resistant material.
[0017] Referring now to FIG. 3(a), which is a side sectional of
electromagnetic pump 10 shown in FIG. 2, optional thermal insulator
26 separates the induction coils from the interior of the pump and
provides a means for molten metal (melt) heat retention for melt in
the pump. In this non-limiting example of the invention, the
thermal insulator is substantially shaped as an open cylinder
bounded by base 18 and yoke 20. Outer tube 28 in this non-limiting
example of the invention, is a substantially cylindrically-shaped
tube that has a closed rounded bottom and an opened top with a
protruding lip around the opening. The outer tube's lip sits on top
of yoke 20. First closing means 30 seats over yoke 20 and the
protruding lip of the outer tube. Second closing means 32 seats
over first closing means 30. Outlet 22 is disposed between the
first and second closing means. Mid tube 34 in this non-limiting
example of the invention is a substantially cylindrically-shaped
tube that is opened at both ends with the upper end having a
protruding lip around the opening. The mid tube's lip is seated in
a recess in second closing means 32. The first and second closing
means are arranged to form an outlet annular volume 42 that
connects the interior passage of outlet 22 to riser annular volume
44 that is disposed between the outer wall of mid tube 34 and the
inner wall of outer tube 28. Third closing means 36 seats over
second closing means 32. Inner tube 40 in this non-limiting example
of the invention is a substantially cylindrically-spaced tube that
has an open bottom and a closed top. As best seen in FIG. 3(c) the
perimeter of the inner tube's open bottom forms a fluid tight seal
with the perimeter of the mid tube's open bottom. Magnetic material
46 is disposed in a volume between the outer wall of inner tube 40
and the inner wall of mid tube 34 as further described below.
Fourth closing means 38 seats over third closing means 36 and the
closed top of inner tube 40. Inlet 24 is disposed between the third
and fourth closing means and its interior passage is connected to
the interior passage of inner tube 40. FIG. 3(b) is a sectional
view that illustrates the spatial relationship of components in a
horizontal plane.
[0018] The above non-limiting examples of the invention provide a
convenient means for assembly or disassembly of pump 10. Removal of
fourth closing means 38 allows inlet 24 and inner tube 40 to be
raised out of the pump. Further removal of third closing means 36
allows magnetic material 46 and mid tube 34 to be raised out of the
pump. Further removal of second closing means 32 allows removal of
outlet 22. Further removal of first closing means 30 allows removal
of outer tube 28.
[0019] The above examples of the invention provide a convenient
means for changing the angular orientation between inlet 24 with
outlet 22. In a particular installation, supply and outlet conduit
(not shown in the drawings) that are to be connected to inlet 24
and outlet 22 respectively, may not be oriented to accept the 180
degrees angular orientation (looking down on the top of the pump)
between the inlet and outlet for pump 10 as shown in FIG. 1. First
closing means 30 and second closing means 32 may be rotated and
secured into a position different from that shown in FIG. 1 to
change the angular orientation of inlet 24 to outlet 22, which
outlet is contained by the first and second closing means. Third
closing means 36 and fourth closing means 38 may be rotated and
secured into a position different from that shown in FIG. 1 to
change the angular orientation of outlet 22 to inlet 24, which
inlet is contained by the third and fourth closing means.
[0020] Molten metal flows through pump 10 in the direction
indicated by the arrows in FIG. 3(a). The melt enters the pump
through inlet 24 and flows down the interior cylindrical passage of
inner tube 40. This section of the pump is referred to as the
supply section. The melt then moves by magnetic forces, as further
described below, up riser annular volume 44 (the magnetic force
pumping section), into outlet annular volume 42, and finally out of
the pump through outlet 22. In other examples of the invention,
outlet 22 may connect directly to riser annular volume 44 rather
than being intermediately connected to it by outlet annular volume
42 formed between the inner wall of mid tube 34 and the inner
annular walls of the first and second annular closing means. The
outer tube, mid tube and inner tube are formed from a suitable heat
resistant material such as a ceramic composition. One non-limiting
type of ceramic composition that may used to cast the outer, mid
and inner tubes, as well as inlet 24 and outlet 22 is a
silicon-aluminum-oxynitride composition known as sialon.
[0021] As disclosed above an applied magnetic force causes the
electrically conductive melt to flow through pump 10. There is
shown in FIG. 4(a) one diagrammatic example of supplying power to
the induction coils to cause the molten metal to flow through pump
10 by magnetic force. Power supply 48 is a three-phase output power
supply with variable output frequency and output voltage. One
suitable type of supply is a solid state supply with a pulse width
modulated output. FIG. 4(b) is a vector diagram illustrating a
six-cycle connection scheme from the power supply to the coils that
is used to produced magnetic forces that act on the molten metal in
riser annular volume 44 to force the melt up the riser annual
volume and through outlet 22, and thus pulling molten metal through
pump 10 from a suitable source of molten metal that can be
connected to inlet 24. As illustrated in the diagram and vector
diagram, the six-cycle scheme is created by sequentially connecting
each of the three phases with alternating positive and negative
phase orientation. That is phase +AB is followed by phase -BC,
which is followed by phase +CA, which is followed by phase -AB,
which is followed by phase +BC, which is followed by phase -CA. The
six-cycle connection scheme for induction coils 12a through 12f
repeats for induction coils 12g through 12l. The choice of a
six-cycle connection scheme is not limiting, but a six-cycle scheme
(with 30 electrical degrees phase angle between voltages in
adjacent coils) provides a more uniform flow rate than, for
example, a three-cycle scheme (with 60 electrical degrees phase
angle between voltages in adjacent coils). Since the magnitude of
the output voltage of power supply 48 is directly proportional to
the magnitude of the magnetic force applied to the molten metal,
varying the output voltage of the power supply will vary the
magnetic lifting force and flow rate of a molten metal through the
pump.
[0022] The magnetic forces generated in riser annular volume 44 are
substantially vertical in the upwards direction since the magnetic
field generated around each of the coils substantially forms a
magnetic circuit with magnetic material 46 and the field path
through the molten metal in the riser annular volume is
substantially horizontally-oriented. If a hot molten metal is
pumped by electromagnetic pump 10, magnetic material 46 must have a
Curie temperature (point at which the magnetic material loses its
magnetic properties) greater than the temperature of the molten
metal flowing through the pump. For these applications a high Curie
temperature magnetic material must be used. For example, molten
aluminum typically may flow through the pump at a temperature
ranging from 680.degree. C. to 800.degree. C. For this application
the magnetic material must have a Curie temperature of at least
850.degree. C. which is the maximum temperature of the aluminum
melt plus design margin. One suitable type of high Curie
temperature magnetic material 46 for this application is a class of
iron-cobalt alloys known as permendur.
[0023] It is preferable, but not required, that each induction coil
be formed as a thin-wire, multiple-turn (typically 500 or more
turns) coil commonly referred to as a bobbin magnetic coil since it
is formed by winding thin wire around a bobbin that is removed
after winding. Since the magnitude of magnetic force created by a
magnetic field is directly proportional to both current flow
through the coil and the number of turns in the coil, using a coil
with a large number of turns keeps the required output current from
power supply 48 at a low level for a given magnitude of magnetic
force.
[0024] If the source of molten metal to the pump is located below
the horizontal level of inlet 24, pump 10 will need to be initially
primed by filing the interior passage of inner tube 40 with melt.
One method of accomplishing this is by attaching a vacuum pump to
outlet 22 and drawing a vacuum on the melt flow passages within
pump 10 to suction melt from a supply of molten metal connected to
inlet 24. In other examples of the invention, the top of inner tube
40 may be open and penetrate through fourth closing means 38 in,
for example, a funnel-shaped opening into which molten metal can be
poured to prime the pump by filling the inner tube.
[0025] When pump 10 is not in use, stationary molten metal in the
pump may cool and "freeze" within the pump's internal flow
passages. To prevent this from happening, a cyclical emptying and
filling of riser annular volume 44 with molten metal may be
electromagnetically accomplished. Reversing the direction of all
phase vectors in FIG. 4(b) will create a magnetic force on molten
metal in riser annular volume 44 that will force it down and push
molten metal back though inlet 24 to the source of molten metal
connected to the inlet. Subsequently reversing all phase vectors
back to the directions shown in FIG. 4(b) will create a magnetic
force that will cause molten metal to rise up in the riser annular
volume. This jogging motion of molten metal will prevent freezing
of molten metal in the pump when it is not in use. In other
examples of the invention, if a three phase power supply is used,
cyclically reversing two of the phases with, for example, solid
state switches, can also be used to accomplish the electromagnetic
jogging motion of melt in the pump. In other examples of the
invention, a heating medium, such as a circulating hot gas or
liquid, or an electric heating element, may be provided in the
volume between thermal insulator 26 and the outer wall of outer
tube 28.
[0026] FIG. 5 illustrates another example of an electromagnetic
pump of the present example. In this example, inlet 24a is at the
bottom of the pump and molten metal is electromagnetically pumped
directly up riser annular volume 44 as generally described in
previous examples of the invention. In this particular example
since molten metal does not flow through the inner tube, the inner
tube may be a totally enclosed tube or other inner structural
element that serves as a means for containing magnetic material 46
between the inner structural element and mid tube 34.
[0027] Other types of power supply and distribution arrangements
are contemplated within the scope of the invention. For example,
multiple single phase power supplies may be used; each coil may be
powered by an individual power supply; or separate power supplies
may power individual groups of coils. Further although in the above
examples of the invention the inner, mid and outer tubes have their
longitudinal axes vertically oriented, the longitudinal axes of the
tubes may be otherwise oriented without deviating from the scope of
the invention.
[0028] The examples of the invention include reference to specific
electrical components. One skilled in the art may practice the
invention by substituting components that are not necessarily of
the same type but will create the desired conditions or accomplish
the desired results of the invention. For example, single
components may be substituted for multiple components or vice
versa.
[0029] The foregoing examples do not limit the scope of the
disclosed invention. The scope of the disclosed invention is
further set forth in the appended claims.
* * * * *