An improved apparatus for removing magnetic material from a flowing fluid such as water by magnetic separation has a single set of electromagnets which are used with a plurality of magnetic filters for continuous magnetic separation operation alternately without obstructing the flow of the fluid being processed. A high-gradient magnetic filter arrangement which passes through a magnetic field generated by the magnets is made up of at least two magnetic filters separated by a watertight partition. When the fluid being processed is flowing through one of the magnetic filters, the other filter is removed from the flow of the fluid into a magnetic filter housing which is separated from the fluid flow through the magnetic filter by means of partitions. Backwashing of this other magnetic filter is carried out while purification of the fluid being processed by the former magnetic filter continues uninterrupted. Dummy magnetic filters are provided at the outer ends of the magnetic filter arrangement so that whichever of the magnetic filters is removed from the flow of the fluid being processed, the filter matrices do not leave the magnetic field formed by the plurality of magnets, and consequently the magnetic filters can be moved in and out of the magnetic field with a minimal driving force.
A high temperature superconductor (HTSC) 5 is magnetized between drive coils 1,2 forming poles of a magnet connected by an iron yoke 9 by relative movement of a vacuum insulated cryostat 4 containing the HTSC and the magnetizing magnet, in order to magnetize a large area of HTSC using a magnet with a small region 3 of magnetizing flux. Alternatively, the HTSC 5 may be contained in an evacuated region of a cryostat containing the magnetizing magnet. An interconnecting chamber allows the HTSC to be moved between an operative region and a magnetizing region without substantial loss of vacuum.
