Vacuum cleaner

A vacuum cleaner, comprising:

• a dirt inlet;
• a motor and fan for delivering suction to the dirt inlet;
• a cyclone unit for separating particles from a flow generated by the suction of the motor and fan, comprising a vortex finder extending along a cyclone axis of rotation and an annular chamber formed around outside of the vortex finder, the annular chamber having a ceiling wall;
• and
• a delivery duct for delivering air to the cyclone unit such that the air flows to the annular chamber, wherein the delivery duct extends in a forward airflow direction, and an outlet from the vortex finder is at a backward end thereof such that the outlet from the vortex finder has a component in an opposite direction to the forward airflow direction,
• wherein:
• a space is provided between a forward end of the vortex finder and the ceiling wall of the annular chamber, wherein the ceiling wall is at a distance from the forward end of the vortex finder,
• and in that the vacuum cleaner further comprises:
• a filter located forward of the vortex finder;
• and
• a passageway that extends from the backward end of the vortex finder to beyond the forward end of the annular chamber leading to the filter, wherein the backward end of the vortex finder is where air exits the vortex finder.