Abstract: An arcuate, preferably cylindrical, magnetic shunt bar supports a plurality of pin magnets having alternate north and south orientations, defining a ring-shaped array of magnets of alternating orientation. The magnet free ends opposite the shunt bar are positioned to conform closely to the shape of a surface to be sealed, forming a narrow gap therebetween containing a multi-polar magnetic field extending beyond the free ends in a direction substantially orthogonal to the surface. The axes of the magnets may be disposed at any desired angular orientation to the surface. Magnetorheological fluid (MRF) in the gap is magnetically stiffened and held as a dynamic seal. The arrangement is useful as a shaft seal, wherein the seal surface passes axially through the array, and also as a wiper for MRF from a carrier surface wherein the surface passes by the array.

Abstract: An arcuate, preferably cylindrical, magnetic shunt bar supports a plurality of pin magnets having alternate north and south orientations, defining a ring-shaped array of magnets of alternating orientation. The magnet free ends opposite the shunt bar are positioned to conform closely to the shape of a surface to be sealed, forming a narrow gap therebetween containing a multi-polar magnetic field extending beyond the free ends in a direction substantially orthogonal to the surface. The axes of the magnets may be disposed at any desired angular orientation to the surface. Magnetorheological fluid (MRF) in the gap is magnetically stiffened and held as a dynamic seal. The arrangement is useful as a shaft seal, wherein the seal surface passes axially through the array, and also as a wiper for MRF from a carrier surface wherein the surface passes by the array.

Abstract: A magnetorheological fluid delivery system includes a mixing and tempering vessel. Fluid is admitted to the vessel via a plurality of tangential ports, creating a mixing of the fluid in the vessel and promoting homogeneity. Fluid may be reconstituted in the vessel by metered addition of carrier fluid. A fixed-speed centrifugal pump disposed in the vessel pressurizes the system. Fluid is pumped through a magnetic-induction flowmeter and a magnetic flow control valve having solenoid windings whereby MR fluid is magnetically stiffened to restrict flow. A closed-loop feedback control system connects the output of the flowmeter to performance of the valve. A nozzle having a slot-shaped bore dispenses MR fluid for re-use in the work zone.

Abstract: An improved system for magnetorheological finishing of a substrate comprising a vertically oriented bowl-shaped carrier wheel having a horizontal axis. The carrier wheel is preferably an equatorial section of a sphere, such that the carrier surface is spherical. The wheel includes a radial circular plate connected to rotary drive means and supporting the spherical surface which extends laterally from the plate. An electromagnet having planar north and south pole pieces is disposed within the wheel, within the envelope of the sphere and preferably within the envelope of the spherical section defined by the wheel. The magnets extend over a central wheel angle of about 120° such that magnetorheological fluid is maintained in a partially stiffened state ahead of and beyond the work zone. A magnetic scraper removes the MRF from the wheel as the stiffening is relaxed and returns it to a conventional fluid delivery system for conditioning and re-extrusion onto the wheel.

Abstract: A magnetorheological fluid delivery system includes a mixing and tempering vessel. Fluid is admitted to the vessel via a plurality of tangential ports, creating a mixing of the fluid in the vessel and promoting homogeneity. Fluid may be reconstituted in the vessel by metered addition of carrier fluid. A fixed-speed centrifugal pump disposed in the vessel pressurizes the system. Fluid is pumped through a magnetic-induction flowmeter and a magnetic flow control valve having solenoid windings whereby MR fluid is magnetically stiffened to restrict flow. A closed-loop feedback control system connects the output of the flowmeter to performance of the valve. A nozzle having a slot-shaped bore dispenses MR fluid for re-use in the work zone.

Abstract: An improved system for magnetorheological finishing of a substrate comprising a vertically oriented bowl-shaped carrier wheel having a horizontal axis. The carrier wheel is preferably an equatorial section of a sphere, such that the carrier surface is spherical. The wheel includes a radial circular plate connected to rotary drive means and supporting the spherical surface which extends laterally from the plate. An electromagnet having planar north and south pole pieces is disposed within the wheel, within the envelope of the sphere and preferably within the envelope of the spherical section defined by the wheel. The magnets extend over a central wheel angle of about 120° such that magnetorheological fluid is maintained in a partially stiffened state ahead of and beyond the work zone. A magnetic scraper removes the MRF from the wheel as the stiffening is relaxed and returns it to a conventional fluid delivery system for conditioning and re-extrusion onto the wheel.