In a screening device, a rotor element on a rotor coaxial with a cylindrical screen drum and a cylindrical screen including: an upper surface and a front face between the surface of the rotor and the upper surface, wherein the front face faces upstream into pulp flow through a gap between the screen drum and the cylindrical screen; a trailing surface extending downstream of the pulp flow from the upper surface, wherein the trailing surface tapers to the surface of the rotor and meets the surface of the rotor at a back region of the trailing surface, and opposite sidewalls extending between the trailing surface and the surface of the rotor, wherein the opposite sidewalls gradually converge towards the back region.