Pulsed-gas stirring of molten metal esp. aluminium - by allowing withdrawn portion of bath to commence return under gravity before pulse is applied

摘要

A portion of molten metal is drawn upwardly from the bath by suction into a tube. Suction is then cut off, and the withdrawn portion commences to fall by gravity, when a compressed gas pulse is applied to the tube to expel the metal. Appts. includes a tube with removable cover and having connected to it a pressurised-gas accumulator and a suction system. A valve system actuated by a float briefly puts the tube interior in communication with the ambient atmos. before discharging a gas pulse through an outlet directed upwardly towards the underside of the cover. The invention is applied to stirring aluminium in large capacity combustion heated reverberatory melting furnaces. The whole of the pulse energy is employed in accelerating the returning metal portion, while interaction of gas and metal is minimised. Melting time can be reduced by 15%.