US 4,834,870 A · Method and apparatus for sorting non-ferrous metal pieces

Abstract

Mixed pieces of different non-ferrous metals are sorted by initially moving the pieces through a high density, rapidly changing magnetic flux field, and immediately thereafter, freely moving the pieces along unsupported forwardly and downwardly directed trajectories resulting from the momentum of the pieces, the force of gravity and the magnetically induced repulsive forces developed in the pieces by the flux field. The magnitude of the magnetically induced repulsive forces differ for different non-ferrous metals so that the lengths of the trajectories of generally similar size and shape pieces vary accordingly for separating pieces formed of different metals. The magnetic field is provided by a horizontally axised, rapidly rotating, hollow, liquid cooled, iron wall drum having magnets affixed to its outer surface. The magnets are arranged in rows that are formed of numerous, tile-like, small, permanent magnets which are positioned end to end, with their like polarity ends adjacent. A belt conveyor, which moves the pieces across the top of the drum, has its discharge end pulley coaxially surrounding the drum so that the pieces freely move off the end of the conveyor belt after passing through the magnetic field. Hence, the lengths of the trajectories may be controlled by adjusting the speed of the conveyor, which adjusts the momentum of the pieces, and by adjusting the rotational speed of the drum for adjusting the frequency of the changes in the magnetic field and, consequently, the magnitude of the induced repulsive forces.

Claims18

Dependent claims

A method of sorting mixed pieces of roughly similar size, which are formed of different non-ferrous metals, comprising essentially the steps of:

physically moving the individual pieces upon a conveyor surface at a predetermined speed in a predetermined direction through a rapidly changing, high flux density magnetic field, sufficient to develop a magnetically induced repulsive force in the pieces which force differs in magnitude for the different non-ferrous metals;
forming the rapidly changing magnetic flux field by placing a rotating drum close to, but beneath, the conveyor surface, with numerous, tile-like, high flux density, permanent magnets affixed upon the drum surface, with each magnet providing a separate magnetic flux field, so that the overall magnetic field of the rotating drum rapidly changes as the magnets move with the drum surface;
forcing the magnetic field upwardly, generally radially away from the drum surface to vary the flux density enveloping the pieces located upon the conveyor surface as they pass over the drum, by means of placing a variable height adjustable, magnetic flux attractive dipole above the conveyor surface and pieces;
adjusting the flux density enveloping the pieces by adjusting the dipole height to predetermined locations;
permitting the pieces to freely continue to travel along an unsupported, downward trajectory along said direction, without support, immediately after passing through said field, under the combined influence of the forces of inertia, gravity and said magnetically induced repulsive force;
whereby the distance that each of the pieces travel from their departure from the magnetic field is affected by its developed magnetically induced repulsive force, so that the different metal pieces separate from each other along their length of travel;
and collecting the separated pieces of metal.

4 more elements

A magnetic sorter for separating mixtures of pieces of different non-ferrous metals, comprising:

a horizontally axised, rotor formed of a cylindrical drum having parallel rows of a number of permanent magnets secured to its outer surface;
the magnets in each row being arranged end to end with like polarities at adjacent ends;
means for rotating the drum about its axis;
a support surface located closely above the drum and within the magnet field above the drum for supporting pieces of metal that are moved on the support surface over the drum transversely of the drum axis;
the magnetic field of the magnets being arranged so that the metal pieces passing over the drum, pass through the field and are momentarily subjected to a rapidly reversing magnetic flux field of sufficient magnitude to induce a magnetic repelling force in each piece, but with the magnitude of the repelling forces varying with different types of non-ferrous metals;
and piece collecting means located at the end of, and below the level of, the support surface so that unsupported pieces may freely continue to move, due to their momentum, in the direction of their movement across the drum and thereafter, drop downwardly due to gravity upon the collecting means, with pieces of different metals tending to separate from each other along their direction of travel, due to their respective, magnetically induced, repelling forces.

3 more elements

A magnetic sorter rotor for producing rapidly reversing magnetic flux fields comprising:

a cylindrical drum having an outer surface and a central axis;
numerous, parallel rows of permanent magnets secured to the outer surface, with each row formed of a number of similar, relatively small, permanent magnets, each arranged end to end with the adjacent magnet and with the adjacent ends of the respective magnets being of the same polarity;
with each row of magnets being longitudinally offset relative to its next adjacent row to offset the ends of the magnets in one row from the ends of the magnets in the next adjacent row;
said drum being rotatable around its axis, whereby the rotating drum provides a series of separate flux fields along its axial length, corresponding to each magnet in each row, which flux fields rapidly reverse relative to a fixed line that is parallel to said center axis and which is located adjacent the drum surface.

1 more element

Dependencies are inferred from the claim text.

Method and apparatus for sorting non-ferrous metal pieces

Life of this patent

Method and apparatus for sorting non-ferrous metal pieces

Life of this patent

Abstract

Claims18