Cold trap with rotating magnetic field

摘要

In cold traps, contaminated metallic fluids are more satisfactorily cleaned if a further velocity component in the peripheral direction with respect to the cold trap excess is impressed on their throughput rate. This is forcibly accomplished by a rotating magnetic field applied on the outside, so that the molten metal covers a longer distance in the annular gap. The separation of the impurities is enhanced by additional flow obstacles in the annular gap. On the one hand, they enlarge the surface in the annular gap and, on the other hand, they force the formation of secondary flows. This assists the mass transfer and hence the precipitation of the impurity.