Patent ID: 8695157

Claim:
A vacuum cleaner configured to operate in a vacuum cleaning mode and a filter cleaning mode, the vacuum cleaner comprising; a vacuum source; a filtering unit for filtering a dust laden air stream, the filtering unit comprising: at least one filter having opposite first and second sides, a filtering unit outlet passage selectively fluidly connecting the second side of the at least one filter to the vacuum source, and a filter cleaning inlet passage selectively fluidly connecting the second side of the at least one filter to a source of ambient air separate from the vacuum source; switching means for switching the vacuum cleaner between the vacuum cleaning mode and the filter cleaning mode; and a separating unit for separating dust from a dust laden air stream; wherein: in the vacuum cleaning mode, the vacuum source is arranged to force a first air stream in a first air stream path through the at least one filter in a first direction from the first side of the at least filter to the second side of the at least one filter to filter out dust from the dust laden air stream, and to the vacuum source, and in the filter cleaning mode, the vacuum source is arranged to force a second air stream in a second air stream path from the filter cleaning inlet passage, through the at least one filter in a second direction from the second side of the at least one filter to the first side of the at least one filter to remove dust from the filtering unit, and to the vacuum source; and wherein the separating unit is, in the filter cleaning mode, connected in the second air stream path between the vacuum source and the filtering unit to separate dust removed from the filtering unit, and, in the vacuum cleaning mode, the separating unit is operatively disconnected from the first air stream path so that dust from the filtering unit only enters the separating unit during the filter cleaning mode.