Alloy casting apparatus

A casting apparatus which enables gravity flow and feeding of alloy in a casting operation, the apparatus comprising:

• a supply vessel for holding a supply of alloy,
• a furnace in which the vessel is contained and in which the vessel is heatable to maintain the supply of alloy at a suitable casting temperature,
• a permanent mould located outside of the vessel and the furnace mounted laterally outwardly from the vessel and the furnace, the mould having dies defining a die cavity,
• a conduit providing communication between the vessel and the mould, the conduit having a main part of its length which extends through and outwardly from the furnace and slopes downwardly relative to the vessel, and
• a drive element operable to reversibly tilt an assembly including the furnace, the vessel and the mould about a substantially horizontal axis to enable or prevent the flow of the alloy through the conduit from the vessel to the die cavity defined by the dies under a pressure head of alloy in the supply vessel, and throughout a range of tilting of the assembly, from a first, non-casting position the assembly occupies on completion of one cycle and before commencement of the next cycle and in which the flow of alloy from the vessel to the die cavity is prevented, to a second, casting position enabling flow from the vessel to the die cavity, to generate the pressure and produce a casting, the mould having a lower die by which alloy is able to be received upwardly into the die cavity by flowing upwardly from the conduit and by which the mould is mounted in relation to the furnace, and an upper die which is moveable relative to the lower die and the furnace for opening and closing the mould, the mould being provided with an arrangement connectable to a source of supply of protective cover gas and enabling the flow of protective cover gas to the die cavity for protecting a surface of molten alloy, at a second end of the conduit, said arrangement including a chamber into which the protective gas is receivable, said arrangement having a plurality of outlets by which the chamber communicates with the die cavity, said arrangement being operable to provide protective cover gas at a positive pressure to the mould for flow into the die cavity on solidification of alloy therein and just prior to tilting of the assembly from the second, casting position to the first, non-casting position whereby, as molten alloy retracts from the mould as the pressure head is reduced, the positive pressure of protective cover gas and a resultant reduction in pressure at the second end of the conduit enabling protective cover gas to flow into the second end of the conduit for protecting the surface of molten alloy in the second end of the conduit, when the mould is open,
• wherein the main part of the conduit slopes at an angle of from about 5° to 15° from a top horizontal surface of the vessel.