porous shaped bodies are disclosed , and an apparatus and method of their production by extruding a homogeneous , single - phase liquid mixture of polymer and mixing partner liquid at the temperature of mixture preparation through a nozzle downwardly with a linear velocity v 1 into a cooling liquid that dissolves the polymer insubstantially or not at all at the cooling temperature , the cooling liquid being provided from entry of the extruded mixture until at least the point of start of solidification thereof in a substantially vertically arranged tubular zone surrounded by a wall , velocity v 2 of cooling liquid in this zone being less than v 1 . the cooling liquid is preferably contained in a u - shaped tube and its level is controllable by dosing at entry and / or exit points .