Electromagnetic Pump
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.
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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 INVENTIONThe present invention relates to electromagnetic pumps that move an electrically conductive fluid by interaction with magnetic fields.
BACKGROUND OF THE INVENTIONElectromagnetic 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.
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 INVENTIONIn 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.
These and other aspects of the invention are set forth in the specification and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGSThe 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.
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
Referring now to
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.
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
Molten metal flows through pump 10 in the direction indicated by the arrows in
As disclosed above an applied magnetic force causes the electrically conductive melt to flow through pump 10. There is shown in
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° C. to 800° C. For this application the magnetic material must have a Curie temperature of at least 850° 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.
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.
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.
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
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.
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.
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.
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.
Type: Application
Filed: Oct 30, 2007
Publication Date: Feb 28, 2008
Applicant: INDUCTOTHERM CORP. (Rancocas, NJ)
Inventors: Vitaly PEYSAKHOVICH (Moorestown, NJ), Oleg FISHMAN (Maple Glen, PA), Emad TABATABAEI (Voorhees, NJ)
Application Number: 11/928,254
International Classification: F04B 15/00 (20060101); F04B 17/00 (20060101);