An airlock for the batch or continuous feeding of a material while obstructing the free flow of a gas. The airlock comprises a continuous belt having a substantially horizontal upper surface and a plurality of non-porous flights projecting out from the belt. Each flight has a free edge located outwardly from the belt. The free edges of the flights seal against a planar sealing surface located above and parallel to the belt. Particulates are transported on the upper surface of belt below and away from any potential grinding action between the moving free edges of the flights and the stationary sealing surface. The flights, located between the sealing surface and the belt, inhibit the flow of air through the airlock.