Patent ID: 7223345

Claim:
A high-gradient magnetic filter for separating weakly magnetizable particles from a circulating fluid medium, comprising a housing adapted to receive a pipe system with a feed and a return, a magnetic circuit disposed in the housing and having two magnetic flux conducting sections which form at least two pole gaps therebetween, a permanent magnet arranged in a first of the at least two pole gaps of the magnetic circuit for generating a magnetic field in another of the at least two pole gaps, said permanent magnet movable between an ON-position and an OFF-position, at least one filter chamber disposed in the pipe system and including a filter element, said filter element located in the other of the at least two pole gaps, and means for directing the fluid medium inside the pipe system through the filter chamber in two opposing flow directions, wherein the magnetic circuit is located external to the pipe system and sealed against the circulating fluid medium, and wherein a high magnetic field gradient is applied across the at least one filter when the permanent magnet is in the ON-position, and the magnetic field across the filter is a remanent magnetic field when the permanent magnet is in the OFF-position.