Sealing top for containers for powdered or granular materials

A seal for a container for powders or granular products having a non-clogging lockable opening for the selective dispensing of the container contents by pressure exerted on the container characterized in that that said seal is provided with an opening terminating in a lock, said opening comprising a substantially uniform inner channel and a substantially uniform outer channel, both of said channels being aligned in the direction of discharge and in a direction perpendicular to the longitudinal axis of the container, said outer channel extending from the inner channel outward and the cross-sectional area and the length of the inner channel each being small relative to the cross-sectional area and the length of the outer channel, the cross-section-to-length ratio of the outer channel being at least 3:4, and said lock blocking the outer channel of said opening, said lock comprising a slider valve movable perpendicularly to the longitudinal direction of discharge, said slider valve being equipped with a porthole having the same contour as the cross-sectional area of the outer channel and which can be made to register with the outer channel and being movably supported in a slider bearing provided on the outside of the outer channel, at least one stop for insuring against loss of said slider being provided at one or both of the slider ends.