A particle separation device includes a particle separation member having a plurality of conical cavities each having a narrow open end and a wide open end for separating particles from unclean liquid; a fluid distribution member for distributing the liquid to the cavities; a particle collection member for collecting particles; and a fluid guiding member for guiding cleaned liquid from the particle separation member to an outlet of the device. The particle collection member includes a chamber and a magnet for holding particles inside the chamber. A vortex finder is disposed in each of the cavities. The vortex finder has a skirt portion and a distal end having a reduced wall thickness.