Patent ID: 6860313

Claim:
A method for the preparation of mould sand in a mixer, the method comprising: configuring the mixer to comprise a mixing chamber capable of holding mould sand, quality-determining components, water or a mixture thereof, the mixing chamber defining a cross-sectional opening area of at least 0.25 square meters therein to facilitate the introduction of the mould sand, quality-determining components, water or a mixture thereof; configuring at least the mixing chamber portion of the mixer to operate under a vacuum; feeding at least one of mould sand, quality-determining components or water through the opening area at a volume flow rate that at least at times equals or exceeds 100 liters per second; and maintaining a vacuum between the mixing chamber and an ambient environment such that a pressure difference arising therefrom functions as at least a predominant driving force for at least a portion of the time required for said feeding of the mould sand, quality-determining components or water into the mixing chamber.