Membraanfiltratie-element

Membrane filtration element comprising at least one flow duct (10) having a membrane wall, a housing (11) enclosing the flow duct (10), a fluid supply (12) which is connected to one end of the flow duct (10), a retentate discharge (14) connected to the other end of the flow duct (10) and a permeate discharge (13) connected to the housing (11). The flow duct (10) extends helically in such a way around an imaginary axis that, if an axial main stream is established in the flow duct (10), a secondary flow is produced whose flow direction is substantially transverse to the direction of the main stream. In particular, the ratio c/a is less than 2.4, where a is the hydraulic radius of the flow duct (10) and c is the radius of the helix formed by the flow duct.