Magnetic device for sorting biological objects
A magnetic device includes a soft magnetic center pole having a tapered tip end, first and second soft magnetic side poles disposed on opposite sides of the soft magnetic center pole, and a magnetic flux source generating magnetic flux in the soft magnetic center pole and the first and second soft magnetic side poles. The first and second soft magnetic side poles have first and second top ends, each end having a chisel edge profile with a bevel side. The magnetic device further includes a flexible conduit nestled in a gap formed between the tapered tip end and the bevel sides of the first and second top ends and a soft magnetic press operable to push and deform the flexible conduit nestled in the gap.
1 . A magnetic device comprising:
a soft magnetic center pole having a bottom end and a tapered tip end;
first and second soft magnetic side poles disposed on opposite sides of the soft magnetic center pole, the first soft magnetic side pole having a first bottom end and a first top end, the second soft magnetic side pole having a second bottom end and a second top end, the first and second top ends each having a chisel edge profile with a bevel side facing outward away from the soft magnetic center pole;
a magnetic flux source generating magnetic flux in the soft magnetic center pole and the first and second soft magnetic side poles;
a flexible conduit nestled in a gap formed between the tapered tip end and the bevel sides of the first and second top ends; and
a soft magnetic press operable to push and deform the flexible conduit nestled in the gap,
wherein the magnetic flux forms a first flux loop between the soft magnetic center pole, the soft magnetic press, and the first soft magnetic side pole and a second flux loop between the soft magnetic center pole, the soft magnetic press, and the second soft magnetic side pole.
2 . The magnetic device of claim 1 , wherein the magnetic flux source includes a soft magnetic bottom shield and a permanent magnet disposed between the soft magnetic bottom shield and the bottom end of the soft magnetic center pole, wherein the first and second bottom ends are disposed above the soft magnetic shield.
3 . The magnetic device of claim 1 , wherein the magnetic flux source includes a soft magnetic bottom shield, a first permanent magnet disposed between the first bottom end and the soft magnetic bottom shield, a second permanent magnet disposed between the second bottom end and the soft magnetic bottom shield, and a third permanent magnet disposed between the bottom end of the soft magnetic center pole and the soft magnetic bottom shield, wherein a magnetization direction of the third permanent magnet is opposite to magnetization directions of the first and second permanent magnets.
4 . The magnetic device of claim 1 , wherein the magnetic flux source includes a first permanent magnet disposed beneath the first bottom end, a second permanent magnet disposed beneath the second bottom end, and a third permanent magnet disposed beneath the bottom end of the soft magnetic center pole, wherein a magnetization direction of the third permanent magnet is opposite to magnetization directions of the first and second permanent magnets.
5 . The magnetic device of claim 1 , wherein the magnetic flux source includes a first permanent magnet disposed between the first soft magnetic side pole and the soft magnetic center pole and a second permanent magnet disposed between the second soft magnetic side pole and the soft magnetic center pole, wherein the first and second permanent magnets have opposite magnetization directions.
6 . The magnetic device of claim 1 , wherein the first and second top ends bend inward toward the soft magnetic center pole.
7 . The magnetic device of claim 1 , wherein the magnetic flux is concentrated from the bottom end to the tapered tip end of the soft magnetic center pole and is divided between the soft magnetic press and the first and second top ends.
8 . The magnetic device of claim 1 , wherein the flexible conduit is in contact with the bevel sides of the first and second top ends.
9 . The magnetic device of claim 1 , wherein the first and second soft magnetic side poles are parallel at the first and second bottom ends, respectively.
10 . The magnetic device of claim 9 , wherein the first and second top ends bend inward toward the soft magnetic center pole.
11 . The magnetic device of claim 10 , wherein the first and second top ends are positioned above the tapered tip end.
12 . The magnetic device of claim 1 , wherein the soft magnetic press has a circular cross section.
13 . The magnetic device of claim 1 , wherein the soft magnetic press has a triangular cross section.