Abstract: An apparatus for directing a liquid through a porous medium includes a fluidic module rotatable about a center of rotation and including a fluid chamber and an inflow structure. A porous medium is disposed in the fluid chamber to allow centrifugal force-effected flow of the liquid impinging on a radially inner portion of the porous medium, to a radially outer portion of the porous medium. The porous medium is laterally at least partially spaced apart from chamber walls of the fluid chamber with respect to the flow, so that a fluid connection exists between the radially inner portion of the porous medium and the radially outer portion of the porous medium outside the porous medium. The inflow structure is configured to limit a centrifugal force-effected inflow of the liquid to the radially inner portion of the porous medium to a first flow rate, wherein a ratio of the first flow rate to a maximum possible flow rate through the porous medium is not greater than two.