Another important application of the magnetic filter is in the use of a rotating magnetic disc as the filter element, particularly for the treatment of machine tool coolants. The disc unit is designed so that it can be mounted at any height alongside a grinding wheel or honing machine. Coolant from the machine tool is fed direct to a clarifying chamber containing the rotating magnetic disc. Ferrous swarf and grindings are removed from the coolant, and then collected off the wheel into swarf containers and withdrawn periodically for emptying.
The entry to the clarifier is a narrow channel into which the coolant leaving the machine is fed under gravity. It then flows past a slowly rotating aluminium disc turning in an opposite direction, inset into the periphery of which are a series of
permanent magnets or magnet assemblies. These collect any ferrous contaminants present in the fluid and lift them clear of the tank, where the magnets are scraped clean by wiper blades, sweeping the contaminants into separate containers.