Perhaps new ideas are best developed without the cluttered backdrop of established techniques clouding one’s thoughts. When Peter Olds an Australian engineer faced the task of elevating sand for metal casting moulds five metres above his foundry floor, he found that traditional devices fell well short of his objectives for economy, compact size, quietness and maintenance free operation. Olds returned to first principles and reversed the normal screw conveyor design, driving the outer casing to rotate around a stationary inner screw.