Abstract: An improved valve system for creating reverse pulses of air through the filter element of a vacuum cleaner in order to shake and drive collected dust from the filter element during operation of the vacuum cleaner, by equipping the vacuum cleaner with a valved conduit downstream from the filter element and upstream from the inlet (vacuum side) of the exhauster wherein the valve consists of a pair of movable rigid sealing surfaces adapted to rotate about a single axis positioned such that one rigid surface opens outwardly towards the exterior of the conduit against the pressure gradient while the other rigid surface opens inwardly towards the interior of the conduit assisted by the pressure gradient.