Electromagnetic eddy current materials separator apparatus and method
First Claim
1. An electromagnetic eddy current materials separator for separating a mixture of feed particles moving along a feedstream according to the electrical conductivities of said particles, comprisinga. an eddy current magnet having a magnet face adjacent the feedstream and a magnet winding for producing a magnetic field adjacent said magnet face upon energization of the winding, said magnetic field having a central spatial zone adjacent said face forming a region of strongest magnetic field influence capable of producing strong eddy current repulsion of material and bordered upstream and downstream relative to the direction of feedstream travel by fringe magnetic field influence zones capable of producing weak eddy current repulsion of materials,b. magnet activating means responsive to control signals applied thereto and connected to said magnet for producing rapid changes in electrical currents in the magnet winding to activate said magnet at selected times,c. eddy current magnet control means for producing said control signals,d. means for directing said mixture of feed particles in the feedstream along a path advancing the feed particles into the region of strongest influence of the magnetic field of said magnet, ande. repository means for collecting particles repulsed by said eddy current magnet.
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Accused Products
Abstract
An electromagnetic eddy current materials separator is disclosed herein for use in separating particles of greater electrical conductivity from particles of lesser electrical conductivity and, in particular, for separating non-ferrous metallics from ferrous metallics and non-metallics. An electromagnet is energized by current pulses, pulsing the magnet several times while each particle is in the field of influence of the magnet causing eddy currents to be developed in the particles and resulting in a repulsive force being developed between the magnet and the material, causing the material to be repelled from the magnet, the repulsive force varying directly with the electrical conductivity of the material and the momentum imparted to such particles varying directly with the number of current pulses occurring while each particle is in the field of influence of the magnet. Current is supplied to the magnet only when conductive materials are detected to be within the region of influence of the magnetic field of the magnet, to reduce the duty cycle of activation of the magnet and reduce the power requirement of the apparatus.
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Citations
22 Claims
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1. An electromagnetic eddy current materials separator for separating a mixture of feed particles moving along a feedstream according to the electrical conductivities of said particles, comprising
a. an eddy current magnet having a magnet face adjacent the feedstream and a magnet winding for producing a magnetic field adjacent said magnet face upon energization of the winding, said magnetic field having a central spatial zone adjacent said face forming a region of strongest magnetic field influence capable of producing strong eddy current repulsion of material and bordered upstream and downstream relative to the direction of feedstream travel by fringe magnetic field influence zones capable of producing weak eddy current repulsion of materials, b. magnet activating means responsive to control signals applied thereto and connected to said magnet for producing rapid changes in electrical currents in the magnet winding to activate said magnet at selected times, c. eddy current magnet control means for producing said control signals, d. means for directing said mixture of feed particles in the feedstream along a path advancing the feed particles into the region of strongest influence of the magnetic field of said magnet, and e. repository means for collecting particles repulsed by said eddy current magnet.
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15. An electromagnetic eddy current materials separator for separating mixtures of feed particles moving along first and second feedstreams according to the electrical condivities of said particles, comprising
a. an eddy current magnet having opposite faces providing first and second magnet faces positioned adjacent said first and second feedstreams, respectively, and a magnet winding for producing a magnetic field upon energization of the winding, said magnetic field having a central spatial zone adjacent each of said magnet faces forming a region of strongest magnetic field influence capable of producing strong eddy current repulsion of material and bordered upstream and downstream relative to the directions of feedstream travel by fringe magnetic field influence zones capable of producing weak eddy current repulsion of materials, b. magnet activating means responsive to control signals applied thereto and connected to said magnet for producing rapid changes in electrical currents in the magnet winding to activate said magnet at selected times, c. means for directing said mixtures of feed particles in the first and second feedstream along a path advancing the feed particles into the regions of strongest influence of the magnetic field of said matnet, and d. repository means for collecting particles repulsed by said eddy current magnet.
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18. The method of separating materials according to their electrical conductivities comprising the steps of
introducing a feedstream of the materials to be separated into the region of strongest influence of the magnetic field of an eddy current magnet, and activating said magnet by a plurality of rapid changes in current through said magnet, whereby eddy currents are induced in said materials in proportion to their electrical conductivities and a repulsive force results between said magnet and said material, the magnitude of each such rapid change in current producing a repulsive force insufficient to separate said material from the feedstream, but the cumulative effects of such rapid changes in current being sufficient to separate highly conductive materials from the feedstream.
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20. The method of separating materials according to their electrical conductivities comprising the steps of
introducing a feedstream of the material to be separated into the region of strongest influence of the magnetic field of an eddy current magnet, activating said magnet by intermittent sets of rapid changes in current through said magnet, the sets of rapid changes in current being of sufficient time duration that the cumulative effects of such rapid changes in currant are sufficient to separate highly conductive materials for the feedstream, and deactivating said magnet at the end of said set of rapid changes in current for a time sufficient to allow any ferrous metals in the feedstream which are captured in said region of strongest influence of the magnetic field to migrate through said region of magnetic field influence prior to reactivation of the magnet.
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21. The method of separating materials according to their electrical conductivities comprising the steps of
introducing a feedstream of the materials to be separated into the region of strongest influence to the magnetic field of an eddy current magnet, detecting the presence of metallic materials either within the region of strongest influence of the magnetic field of the magnet or about to enter said region of strongest influence of the magnetic field, and activating said magnet by a plurality of rapid changes in current through said magnet in response to the detection of metallic materials within the region of strongest influence of the magnetic field of the magnet, or about to enter the region of strongest influence of the magnetic field of the magnet.
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22. The method of separating materials according to their electrical condivities comprising the steps of
introducing a feedstream of the materials to be separated into the region of strongest influence of the magnetic field of an eddy current magnet, detecting the presence of metallic materials either within the region of strongest influence of the magnetic field of the magnet or about to enter said region of strongest influence of the magnetic field, and activating said magnet by a plurality of rapid changes in current through said magnet in response to the detection of metallic materials within the region of strongest influence of the magnetic field of the magnet, and deactivating said magnet in response to the absence of metallic materials both within the region of strongest influence of the magnetic field of the magnet, or about to enter the region of strongest influence of the magnetic field of the magnet, whereby the magnet is activated for substantially only that period of time during which metallic materials are within the region of strongest influence of the magnetic field of the magnet.
Specification