Patent ID: 7134479
Filing Date: 2006-11-14
Classification: B22C,B22D

Abstract:
1. A sand mould for making a metal casting; comprising: a mould cavity having a shape corresponding to that of the metal casting, a launder section for engagement with a liquid metal filling system, primary risers connecting the launder section to the mould cavity, sealing means for disengagement from the liquid metal filling system when the mould cavity has been filled, and a pressure riser connected to the launder section and the primary risers; wherein, when the sand mould is in a filling position, the primary risers extend upwardly to the mould cavity and the pressure riser extends upwardly outside the mould cavity and is filled with liquid metal along with mould cavity; and wherein, when the sand mould is rotated 180° from its filling position to an inverted position, the pressure riser maintains a constant pressure in the liquid metal in the mould cavity through the primary risers.