Magnetic device

Claim 1

A magnetic separator for removing colloidal and subcolloidal ceramic magnetic components and paramagnetic components from a fluid carrier comprising, in combination, a substantial volume of ferromagnetic corrosion resistant wool material having a plurality of paths therethrough along which the carrier and components can travel to effect intimate contact between the carrier and said wool, a coil wound about the wool material and adapted to be connected to a source of electric current to produce a background field within the volume occupied by the wool material of an intensity of at least an average strength of 12,000 gauss, the 12,000 gauss field being substantially stronger than that required to magnetize the magnetic wool material to saturation throughout said volume and of sufficient intensity substantially to magnetize ceramic magnetic components and paramagnetic components in the carrier such that said components are subjected simultaneously to the background field and a strong magnetic field gradient in the vicinity of the magnetic wool material, said background field and field gradient being sufficiently high in relation to the particle size of the components to attract and retain said components, a source of electric potential connected to energize the coil and adapted to be disconnected to allow flushing of the components from the wool material, and eddy-current means including a further source of electric potential connected to introduce an AC magnetic field having a skin depth that is less than the characteristic dimensions of the wool fibers in the direction of field penetration to provide vibratory action during the flushing, the frequency of the eddy-current field being at least in the upper sonic range of the order of 18,000 to 20,000 cycles per second and up.