Flux diverting flow chamber for high gradient magnetic separation of

Abstract

A system for the magnetic separation of fragile particles, such as intact biological cells, from a fluid medium. The system includes at least one high-gradient magnetic separator having a flow chamber housing an interstitial separation matrix and associated magnetizing apparatus for coupling magnetic flux to the matrix. The matrix has interstices through which a carrier fluid carrying the cells-to-be-separated may be passed. The magnetizing apparatus includes opposing North and South poles and field-guiding pole pieces, external to the flow chamber. The flow chamber comprises a dual-position flux-coupler. The flux-coupler is operative in a first position in the capture phase and in a second position in an elutriation phase. In the capture phase, the flux-coupler is positioned to permit the magnetic flux from one magnetic pole to pass through the matrix to the other magnetic pole. As the carrier fluid flows through the interstices of the matrix in this phase, particles, such as blood cells, in the input fluid are retained in the matrix, where magnetic forces dominate gravitational and viscous forces. In the elutriation phase, the flux-coupler is positioned so that magnetic flux is diverted from the matrix. In this phase, magnetic flux is greatly reduced in the matrix, permitting viscous forces to the fluid to remove the magnetic particles from the matrix at low flow velocities.