Abstract: A device and a method for repeatedly modifying the composition of a fluid. The device includes a first module (19) modifying the composition of the fluid, a second module (21) modifying the composition of the fluid and a dwell module (20) with an inlet (8) and an outlet (10). The first module is connected in a fluid-conducting manner to the dwell module inlet and the dwell module outlet is connected in a fluid-conducting manner to the second module. Either the first or the second module is a filter unit, or the first module is a first filter unit and the second module is a second filter unit. The filter unit(s) include(s) at least one first filter medium (4, 14) delimiting a supply channel (2, 12) and a retentate channel (1, 11) and at least one second filter medium (5, 15) delimiting the retentate channel and a permeate channel (3, 13).

Abstract: A method for degassing a cross-flow diafiltration unit, a cross-flow diafiltration method and a cross-flow diafiltration unit.

Abstract: A device and a method for repeatedly modifying the composition of a fluid. The device includes a first module (19) modifying the composition of the fluid, a second module (21) modifying the composition of the fluid and a dwell module (20) with an inlet (8) and an outlet (10). The first module is connected in a fluid-conducting manner to the dwell module inlet and the dwell module outlet is connected in a fluid-conducting manner to the second module. Either the first or the second module is a filter unit, or the first module is a first filter unit and the second module is a second filter unit. The filter unit(s) include(s) at least one first filter medium (4, 14) delimiting a supply channel (2, 12) and a retentate channel (1, 11) and at least one second filter medium (5, 15) delimiting the retentate channel and a permeate channel (3, 13).

Abstract: A bioreactor having a filter unit and a method for treating a cell broth. The filter unit has a supply channel (2), a first filter medium (4), a retentate channel (1), a second filter medium (5) and a permeate channel (3), arranged so that the first filter medium delimits the supply channel and the retentate channel from one another; and the second filter medium delimits the retentate channel and the permeate channel from one another. The supply channel is connected to an inlet for a supply medium; the retentate channel is connected to an inlet for a cell broth and to an outlet for the cell broth; the permeate channel is connected to an outlet for a permeate; and the interior of the bioreactor is connected to the inlet for the cell broth and to the outlet for the cell broth.