Apparatus for producing metallic castings by progressively melting a solid charge

摘要

For producing metallic castings an upright crucible is provided, the crucible having a compressible lining made from mineral wool and a bottom sprue opening into a mould supported within a casting box. A high frequency heating coil surrounding the crucible serves to heat up and melt a solid metallic charge so placed within the crucible that an initial gap is left between the lining and the charge, the heating coil being so designed as to effect a progressive melting of the charge from the top down such that the initially melted upper part of the charge flows downwardly through the gap and re-freezes in the lower part of the crucible so as to prevent premature discharge of any of the metal through the sprue until the entire volume of the charge has reached its molten state and attains a temperature higher than the melting temperature whereupon the entire charge is then quickly discharged through the sprue into the mould.