A machine is disclosed to bag powdery material wherein primary and secondary preconditioning chambers are used, having a volume sufficient to give enough time for the powdery material to become de-aerated. This de-aerated powdery material is then supplied to a bulk filling station and a dribble filling...http://www.google.es/patents/US4074507?utm_source=gb-gplus-sharePatente US4074507 - Bag filling machine for powdery material
