Abstract: An aeration apparatus to ease the emptying of a mass of powdered material from any kind of container. The apparatus comprises a vibrating membrane coupled to a device for pulling and fastening it to the container wall, so that said membrane adheres to the inner surface of the container wall. The apparatus is characterized in that the inner surface of membrane has a number of grooves shaped as radial recesses formed only on the lower half of the inner surface of the membrane itself. Each radial section of any radial recess is advantageously venturi-shaped.