Magnetic filter systems and methods
Magnetic filter systems may be constructed with various arrangements of permanent magnets, including but not limited to checkerboard and spiral arrangements. When coupled to a conventional filter, exemplary magnetic filter systems capture ferrous particulates against the outer wall of the conventional filter by magnetic attraction, thereby reducing the number of particulates in a fluid stream and improving the quality of the filtered fluid.
1. A magnetic filter assembly, comprising:
a structural frame having a mounting cavity;
a flux return plate disposed within the mounting cavity; and
a magnetic component comprising an interleaved series of permanent magnets of alternating polarity,
wherein, when the magnetic filter assembly is coupled to a cylindrical oil filter, the interleaved series of permanent magnets extends along 100% of the axial length of the cylindrical oil filter, and a magnetic border in the magnetic component extends continuously along the axial length of the cylindrical oil filter.
2. The magnetic filter assembly of claim 1 , wherein the interleaved series of permanent magnets is configured with at least one of a checkerboard pattern, a spiral pattern, a stretcher bond pattern, a raking stretcher bond pattern, or a monk bond pattern.
3. The magnetic filter assembly of claim 1 , wherein the magnetic component is configured in the shape of a partial cylinder.
4. The magnetic filter assembly of claim 1 , wherein each permanent magnet in the interleaved series of permanent magnets is characterized by a magnet length dimensioned along the longitudinal axis of a partial cylinder, a magnet inner width dimensioned along the circular arc of the partial cylinder, and a magnet height dimensioned parallel to a magnetic axis of each permanent magnet, and
wherein, for each permanent magnet, the ratio of the magnet inner width to the radius of the circular arc is between 0.3 and 0.5, and the ratio of the magnet height to the magnet inner width is between 0.3 and 0.6.
5. The magnetic filter assembly of claim 4 , wherein, for each permanent magnet in the interleaved series of permanent magnets, the ratio of the magnet inner width to the radius of the circular arc is between 0.3 and 0.4, and wherein, for each permanent magnet in the interleaved series of permanent magnets, the ratio of the magnet height to the magnet inner width is between 0.45 and 0.55.
6. The magnetic filter assembly of claim 1 , wherein, when an oil filter comprising an oil filter media disposed within an oil filter wall is coupled to the magnetic filter assembly, the magnetic component causes a magnetic gradient*magnetic field product of at least ((0.1 Tesla/mm)*1 Tesla) to arise in a portion of an oil filter volume between the oil filter wall and the oil filter media.
7. The magnetic filter assembly of claim 1 , wherein the interleaved series of permanent magnets of alternating polarity are oriented such that a magnetic axis of each permanent magnet is perpendicular to the flux return plate.
8. The magnetic filter assembly of claim 1 , wherein the flux return plate comprises a first steel plate and a second steel plate, and wherein the first steel plate is disposed between the interleaved series of permanent magnets of alternating polarity and the second steel plate.
9. The magnetic filter assembly of claim 8 , wherein the first steel plate comprises a material having a higher saturation than the material comprising the second steel plate, and wherein the second steel plate comprises a material having a higher relative permeability than the material comprising the first steel plate.
10. The magnetic filter assembly of claim 1 , wherein the magnetic component is configured with a magnetic border length in excess of 1.25 units of length per unit of area.
11. The magnetic filter assembly of claim 1 , wherein, when the magnetic filter assembly is coupled to an oil filter, the magnetic component results in a flow coverage ratio of at least 50% in the oil filter.