COLD CRUCIBLE INDUCTION FURNACE WITH EDDY CURRENT DAMPING

摘要

Apparatus and method are provided for damping the induced fluid flow, particularly in the region of the base plate (14), in an electrically conductive material that is heated and melted in a cold crucible induction furnace (10). Damping is accomplished by establishing a dc magnetic field (99)such that flow of the electrically conductive liquid metal in that dc magnetic field (99) would induce eddy currents in the liquid metal (93) which would generate forces that tend to oppose the flow. The dc magnetic field (99) may be established by dc current flow in the ac induction coil (68) that induces current in the material, dc current flow in a separate dc coil (73, 75), or coils, constructed to prevent excessive induced losses, by discrete magnets, or a combination of any of the three prior methods.