Abstract: Apparatus for filling containers with difficultly-flowable material, comprising a separator including a filter, a funnel-shaped outlet, and a dust-free butterfly valve for controlling flow of powder through said outlet; and a suction device for conveying said powder by suction to said separator; said outlet adapted to be connected to the container to be filled; said separator being operable to filter powder from the air conveying said powder into the separator and allowing the separated powder to fall into said funnel-shaped outlet. The invention is especially designed for emptying and filling fire-extinguishers.