Abstract: A device for preparing moulding sand. The device includes a mixer configured to operate under at least a partial vacuum and at least one feeder to introduce components to be mixed. An inlet in the mixer is of sufficient size to allow rapid introduction of the components into the mixer from the feeder. The combination of large inlet opening and a pressure differential between the mixer and the feeder significantly reduces the time required to fill the mixer. In addition, the presence of the pressure differential made possible by the vacuum in the mixer reduces the likelihood that airborne contaminants resident in the mixer will migrate outside the mixer. Optional moveable conveyor chutes minimize contact of airborne contaminants with adjacent equipment, while optional mixing tools facilitate the introduction of powdered additives into the mixer.

Abstract: The invention relates to a method for the preparation of foundry sand by means of a mixing process which is carried out in a mixer (1), said preparation occurring at least partially in a vacuum. In order to provide a method and device for the preparation of low-cost foundry sand which can be used in an efficient manner, whereby said foundry sand has a uniform temperature and homogeneous quality in addition to being able to be charged more quickly and therefore economically in comparison with other mixers, the foundry sand is added, at least intermittently, in the form of a volume flow of at least 100 l/s through an opening in the mixer which has a cross-sectional area of at least 0.25 m2, preferably at least 0.4 m2, more preferably at least 0.5 m2.