Magnetic separator

• US 5,483,042 A
• Filed: 11/20/1992
• Issued: 01/09/1996
• Est. Priority Date: 06/04/1990
• Status: Expired due to Term

• Current Assignee: Nordson Corporation
• Original Assignee: Nordson Corporation
• Inventors: Sprenger, Robert A., Raffa, Ray C.
• Primary Examiner(s): HOANG, TU BA
• Application Number:
  US07/984,174
• Time in Patent Office: 1,145 Days
• Field of Search: 219/10.75, 219/10.79, 219/10.61 R, 219/10.43, 219/10.69, 219/647, 219/657, 219/653, 219/654, 219/658, 219/632, 219/648, 219/645, 34/23, 186/379.7, 209/609, 209/552, 209/636, 209/930, 209/905, 414/96, 414/117, 414/120, 198/690.1
• US Class Current: 219/647
• CPC Class Codes: B03C 1/253 obtained by a linear motor
• CPC Class Codes: H01F 7/0247 Orientating, locating, transporting arrangements
• CPC Class Codes: H05B 6/103 multiple metal pieces successively being moved close to the inductor
• CPC Class Codes: H05B 6/36 Coil arrangements
• CPC Class Codes: H05B 6/44 having more than one coil or coil segment

Abstract

Apparatus for spacing a plurality of substantially plate-like ferromagnetic workpieces such as can lids, in face-to-face relationship along a row, comprises a plurality of magnetic elements, each extending longitudinally along the row and different ones of the elements being disposed at different angular positions around the row, each of the magnetic elements being disposed and oriented to prevent the workpieces from pivoting about a distal edge of the workpiece due to the combined magnetic attraction of the workpiece by all others of the magnetic elements.

Claims

1. Apparatus for spacing a plurality of substantially plate-like workpieces in face-to-face relationship along a substantially horizontal row, which workpieces are influenced by magnetic forces, said apparatus comprising a plurality of magnetic elements, each extending longitudinally along said row and being substantially horizontally oriented and disposed at different angular positions around said row, each particular one of said magnetic elements being disposed and oriented to prevent each given one of said workpieces from pivoting about a distal edge of said given workpiece due to the combined magnetic attraction of said given workpiece by all of said magnetic elements other than said particular magnetic element, said magnetic elements operating to space said workpieces apart along said row.

2. Apparatus according to claim 1, wherein said workpieces comprise can ends.

3. Apparatus according to claim 1, wherein each particular one of said magnetic elements comprises a pair of opposite magnetic poles each extending longitudinally and substantially parallel to each other along said particular magnetic element, said poles being oriented to create a magnetic flux path passing through said row.

4. Apparatus according to claim 3, wherein the poles of said magnetic elements alternate magnetic polarities circumferentially around said row.

5. Apparatus according to claim 3, wherein each particular one of said magnetic elements comprises first and second permanent magnets each extending longitudinally and substantially parallel to each other along said particular magnetic element, said first permanent magnet having a north pole directed radially toward said row and further having a south pole, and said second permanent magnet having a south pole directed radially toward said row and further having a north pole.

6. Apparatus according to claim 5, further comprising:

an induction coil at least partly enclosing said row circumferentially; and

a source of medium frequency oscillating electrical current coupled to said induction coil,

wherein said first and second permanent magnets in each of said magnetic elements have low electrical conductance.

7. Apparatus according to claim 5, wherein each particular one of said magnetic elements further comprises a pole piece magnetically coupling the south pole of the first permanent magnet to the north pole of the second permanent magnet of the particular magnetic element along substantially the entire length of said row.

8. Apparatus according to claim 1, further comprising a retaining surface disposed between a particular one of said magnetic elements and said row of workpieces such that an edge of one of said workpieces, which edge is proximate to the particular magnetic element and is attracted radially toward said particular magnetic element, is engaged by said retaining surface and prevented from reaching said particular magnetic element.

9. Apparatus according to claim 8, wherein said retaining surface is nonmagnetic.

10. Apparatus according to claim 8, wherein said retaining surface is smooth to facilitate longitudinal motion relative to said retaining surface of edges of said workpieces which engage said surface.

11. Apparatus according to claim 1, further comprising a non-magnetic retaining surface disposed between each of said magnetic elements and said row of workpieces such that an edge of one of said workpieces which is attracted radially toward a particular one of said magnetic elements is engaged by one of said retaining surfaces and prevented from reaching the particular magnetic element, each of said retaining surfaces being smooth to facilitate longitudinal motion relative to said retaining surfaces of said workpieces while edges of said workpieces engage said surface.

12. Apparatus according to claim 1, wherein said workpieces are ferromagnetic.

13. Apparatus according to claim 1, wherein none of said plurality of magnetic elements is disposed directly below said row.

14. Apparatus according to claim 1, wherein said row has an input end and a longitudinally opposed exit end, further comprising means for adding workpieces to said input end and means for removing workpieces from said exit end, to thereby move workpieces along said row in a direction from said input end toward said exit end.

15. Apparatus according to claim 14, further comprising means for forcing air longitudinally into said row from said input end.

16. Apparatus according to claim 1, further comprising mounting means for holding said magnetic elements radially closer to said workpieces at a first longitudinal position along said row, and radially farther from said workpieces at a second longitudinal position along said row.

17. Apparatus according to claim 16, wherein said first longitudinal position constitutes an exit end of said row and said second longitudinal position constitutes an input end of said row, further comprising means for adding workpieces to said input end and means for removing workpieces from said exit end, to thereby move workpieces along said row in a direction from said input end toward said exit end.

18. Apparatus according to claim 1, wherein said row is substantially straight.

19. Apparatus according to claim 1, wherein said row includes a curved segment.

55. Apparatus according to claim 16, wherein said mounting means is radially adjustable at one of said first and second longitudinal positions.

20. Apparatus for magnetically spacing a plurality of can ends in face-to-face relationship along a conveyance path, said can ends each having two faces and a circumfential edge, said can ends including a material which is influenced by magnetic forces, said apparatus comprising:

a feeder which feeds said can ends into said conveyance path;

a first magnetic element extending longitudinally along said path, said first magnetic element having a north pole extending longitudinally along said path and directed substantially radially toward said path, said first magnetic element further having a south pole extending substantially parallel to said north pole of said first magnetic element and directed substantially radially toward said path; and

a second magnetic element extending longitudinally along said path, said second magnetic element having a north pole extending longitudinally along said path and directed substantially radially toward said path, said second magnetic element further having a south pole extending substantially parallel to said north pole of said second magnetic element and directed substantially radially toward said path,

said first and second magnetic elements opposing each other diametrically across said path, and being spaced substantially equally from said path radially at each longitudinal position along said path for operating to space can ends apart along said path.

21. Apparatus according to claim 20, wherein said first and second magnetic elements are mounted radially more closely to said path at one end of said path than at the other end of said path.

22. Apparatus according to claim 20, wherein said first magnetic element comprises:

a first permanent magnet having a north pole directed substantially radially toward said path and a south pole directed substantially radially away from said path;

a second permanent magnet having a south pole directed substantially radially toward said path and a north pole directed substantially radially away from said path; and

a first material which conducts magnetic flux lines, disposed between the south pole of said first permanent magnet and the north pole of said second permanent magnet;

along substantially the entire length of said first magnetic element,

and wherein said second magnetic element comprises;

a third permanent magnet having a north pole directed substantially radially toward said path and a south pole directed substantially radially away from said path;

a fourth permanent magnet having a south pole directed substantially radially toward said path and a north pole directed substantially radially away from said path; and

a second material which conducts magnetic flux lines, disposed between the south pole of said third permanent magnet and the north pole of said fourth permanent magnet along substantially the entire length of said second magnetic element.

23. Apparatus according to claim 20, further comprising a retaining surface disposed between each of said magnetic elements and said path such that edges of said can ends, when attracted radially toward one of said magnetic elements, are engaged by the retaining surface and prevented from reaching said one of said magnetic elements.

59. Apparatus according to claim 20, wherein said can ends are made of a ferromagnetic material.

60. Apparatus according to claim 22, wherein said first material comprises a pole piece magnetically coupling the south pole of said first permanent magnet to the north pole of said second permanent magnet along substantially the entire length of said first magnetic element,

and wherein said second material comprises a pole piece magnetically coupling the south pole of said third permanent magnet to the north pole of said fourth permanent magnet along substantially the entire length of said second magnetic element.

24. Apparatus for magnetically spacing a plurality of ferromagnetic can ends in face-to-face substantially horizontal relationship along a conveyance path, said can ends each having two faces and a circumferential edge, comprising:

a feeder which feeds said can ends into said conveyance path;

a first magnetic element extending longitudinally along said path, said first magnetic element including a first permanent magnet having a north pole directed substantially radially toward said path and a south pole directed substantially radially away from said path, a second permanent magnet having a south pole directed substantially radially toward said path and a north pole directed substantially radially away from said path, and a pole piece magnetically coupling the south pole of said first permanent magnet to the north pole of said second permanent magnet along substantially the entire length of said first magnetic element;

a second magnetic element extending longitudinally along said path, said second magnetic element including a third permanent magnet having a north pole directed substantially radially toward said path and a south pole directed substantially radially away from said path, a fourth permanent magnet having a south pole directed substantially radially toward said path and a north pole directed substantially radially away from said path, and a pole piece magnetically coupling the south pole of said third permanent magnet to the north pole of said fourth permanent magnet along substantially the entire length of said second magnetic element; and

a retaining surface disposed between each of said magnetic elements and said path such that edges of said can ends, when attracted radially toward one of said magnetic elements, are engaged by the retaining surface and prevented from reaching said one of said magnetic elements,

said first and second magnetic elements opposing each other diametrically across said path, and being spaced substantially equally from said path radially at each longitudinal position along said path,

said first and second magnetic elements being mounted radially closer to said path at one end of said path than at the other end of said path for operating to space can ends apart along said conveyance path.

25. Apparatus for treating a plurality of ferromagnetic can ends, comprising:

means for holding said can ends in substantially horizontal relationship to each other; and

magnetic means, extending longitudinally along said means for holding to produce a magnetic field passing through the can ends, to maintain said can ends in spaced, face-to-face relationship, and to cause said can ends to be magnetically spaced apart by sharing said magnetic field for maintaining said can ends in spaced, face-to-face relationship and spacing said can ends apart magnetically.

26. Apparatus according to claim 25, further comprising means for circulating air between said can ends.

28. Apparatus according to claim 25, wherein said means for holding includes a surface directly contacting said can ends, further comprising:

vibratory means for overcoming friction between said can ends and said surface.

29. Apparatus according to claim 25, wherein said can ends form a row of can ends, and wherein said magnetic means comprises channel magnets extending longitudinally along said row.

30. Apparatus according to claim 25, wherein said can ends form a row of can ends, and wherein said magnetic means comprises a flexible permanent magnet extending longitudinally along said row.

31. Apparatus according to claim 29, further comprising a surface extending longitudinally along said row, said magnets attracting said can ends to said surface, said apparatus further comprising vibration means for vibrating said can ends.

32. Apparatus according to claim 25, further comprising moving means for moving said can ends along a substantially horizontal path.

33. Apparatus according to claim 32, wherein said path is slanted slightly downward, and wherein said moving means operates at least in part gravitationally.

34. Apparatus according to claim 32, wherein said means for holding has an input end and an exit end, and wherein said moving means comprises:

means for adding can ends to said input end of said means for holding; and

means for removing can ends from said exit end of said means for holding.

35. Apparatus according to claim 31, wherein said vibration means is further for moving said can ends magnetically and longitudinally in a direction in which they are spaced.

36. Apparatus according to claim 25, wherein said substantially horizontal relationship includes a slight slant downward by a predetermined angle to a horizontal plane of a conveyance path,

further comprising means for adding can ends to the higher end of said slant,

said particular angle being chosen such that one can end drops out the lower end of said slant in response to each addition of a can end to the higher end of said row.

37. Apparatus according to claim 25, wherein said can ends form a row of can ends oriented in face-to-face relationship, and when said means for holding and said magnetic means for spacing comprise:

a plurality of magnetic elements, each extending longitudinally along said row and being disposed at different angular positions around said row, each particular one of said magnetic elements being disposed and oriented to prevent each given one of said can ends from pivoting about a distal edge of said given can end due to a combined magnetic attraction of said given can end by all of said magnetic elements other than said particular magnetic element.

41. Apparatus according to claim 25 further, comprising:

treating means for treating said can ends; and

magnetic moving means for magnetically moving said can ends along a conveyance path through said treating means.

42. Apparatus according to claim 41, wherein said magnetic moving means comprises:

a plurality of electromagnets disposed longitudinally along said conveyance path; and

control means for energizing said electromagnets sequentially.

43. Apparatus according to claim 42, wherein said control means energizes said electromagnets in at least three phases.

44. Apparatus according to claim 42, wherein said can ends are ferromagnetic, and wherein said control means energizes said electromagnets in a manner which attracts each of said can ends toward each next sequential one of said electromagnets.

45. Apparatus according to claim 42, wherein said can ends are aluminum, and wherein said control means energizes said electromagnets in a manner which repels each of said can ends away from one of said electromagnets toward the next sequential one of said electromagnets.

46. Apparatus according to claim 41, further comprising means for holding said can ends in substantially face-to-face relationship.

47. Apparatus according to claim 42, further for inductively heating said can ends, wherein said control means comprises means for energizing said electromagnets sequentially with bursts of AC current.

48. Apparatus according to claim 47, wherein said bursts of AC current each have a frequency between about 6 kHz and about 20 kHz.

54. Apparatus according to claim 41, comprising:

means for holding said can ends in face-to-face relationship along a curved course; and

a flexible permanent magnet disposed longitudinally along said curved course.

27. Apparatus for spacing a plurality of substantially plate-like ferromagnetic workpieces in face-to-face relationship along a non-vertical row, comprising a plurality of magnetic elements, each extending longitudinally along said row, oriented substantially parallel to said row and disposed at different angular positions around said row, said magnetic elements being disposed and oriented to, and operating to, maintain said workpieces in face-to-face relationship due to a combined magnetic attraction of said magnetic elements.

38. Apparatus for spacing a plurality of workpieces along a substantially horizontal row, comprising:

a first magnet extending longitudinally along said row; and

mounting means for holding said first magnet closer to said row at a first longitudinal position along said row, and farther from said row at a second longitudinal position along said row.

39. Apparatus according to claim 38, further comprising a second magnet extending longitudinally along said row, said first and second magnets being disposed at different angular positions around said row, said mounting means being further for holding said second magnet closer to said row at said first longitudinal position along said row, and farther from said row at said second longitudinal position along said row.

40. Apparatus according to claim 38, wherein said workpieces are can ends.

49. Apparatus for handling a plurality of ferromagnetic can ends, comprising:

spacing means extending longitudinally along a conveyance path to produce a magnetic field for maintaining said can ends in substantially face-to-face relationship and to cause, said can ends to be magnetically spaced apart by sharing said magnetic field; and

moving means for moving said can ends magnetically along said conveyance path.

50. Apparatus according to claim 49, further comprising means for holding said can ends in substantially horizontal relationship while being spaced and moved.

51. Apparatus according to claim 49, wherein said spacing means comprises a channel magnet extending longitudinally along said conveyance path, said can ends being maintained in face-to-face relationship and spaced along said conveyance path, further comprising a surface extending longitudinally along said conveyance path, said channel magnet attracting said can ends to said surface, and wherein said moving means comprises a plurality of sequentially energized electromagnets disposed longitudinally along said conveyance path, each of said electromagnets disposed to attract at least one of said can ends away from said surface when energized.

52. Apparatus according to claim 51, wherein said surface comprises a surface of said channel magnet.

53. Apparatus according to claim 51, wherein said surface comprises a portion of the inner surface of a tube extending longitudinally along and substantially enclosing said conveyance path.

56. An oven for heating a plurality of substantially plate-like ferromagnetic workpieces disposed in face-to-face relationship along a row, comprising:

a plurality of magnetic elements, each extending longitudinally along said row and disposed at different angular positions around said row, each of said magnetic elements being disposed and oriented to, and being effective to, maintain said workpieces in spaced face-to-face relationship due to the combined magnetic fields of said magnetic elements; and

a heater for heating said workpieces along said row.

57. Apparatus for spacing a plurality of ferromagnetic can ends in face-to-face relationship along a conveyance path, comprising:

a plurality of magnetic elements each extending longitudinally along said path, each given one of said magnetic elements having a north pole extending longitudinally along said path and directed substantially radially toward said path, and each given one of said magnetic elements further having a south pole extending substantially parallel to the north pole of the given magnetic element and directed substantially radially toward said path,

said magnetic elements being disposed at different angular positions around said path in a manner which maintains said can ends in face-to-face relationship.

58. Apparatus according to claim 57, wherein said plurality of magnetic elements consists of two magnetic elements, said two magnetic elements opposing each other diametrically across said path and being spaced substantially equally from said path radially at each longitudinal position along said path.