Low pressure casting of light metal and alloys etc. - using furnace with separate melting and holding zones

摘要

The raw material is fed into a furnace zone (a) held at a much higher temp. than the m.pt. of the material, whereas the molten material is held in a separate furnace zone (b) at a lower temp. suitable for casting. The overheating of the material in zone (a) is prevented by gravity, the melt flowing quietly downwards without turbulence into zone (b) and underneath the oxide skin on the molten metal in zone (b). The pref. plant includes a tubular furnace sloping downwards towards its outlet end, which has a vertical outlet pipe up which the melt is driven from zone (b) by a pressurised gas fed into the inlet end of zone (a). The outlet pipe leads to a mould or die in which the metal is cast. Accurate temp. control of zone (b) without temp. fluctuations caused by the entry of cold, solid metal.