Separation device comprising a swirler of a sheet material comprising a plurality of vanes (4) with a flow entrance side edge (6) defining an entrance angle (α) and a flow exit side edge (8) defining an exit angle (β). The flow entrance side edge and flow exit side edge extend from a center section (3) to a peripheral edge (9), which extends between end points of the flow entrance edge and the flow exit edge. The entrance angle is larger than the exit angle.