Method for producing a selectively permeable separation module

A method for casting a polymeric membrane on the inside surface of multiple porous wall tubes of a tubular module to create a permeate separation system, the steps comprising:

• (a) forming a polymer solution consisting of a polymer dissolved in a liquid solvent;
• (b) pouring the polymer solution into the porous tubes of a tubular module, said porous tubes having a cap at one end;
• (c) capping the other end of the porous wall tubes so that the polymer solution is sealed within the porous tubes;
• (d) aligning the longitudinal axis of the tubular module in a substantially horizontal position;
• (e) rotating the aligned tubular module about its longitudinal axis at a speed of less than 60 revolutions per minute so that the polymer solution solvent evaporates through the porous wall tubes to provide a polymer film having a uniform thickness on the inside surface of the porous wall tubes, the polymer film and porous wall tubes thereby constituting the permeate separation system.

A permeate filter system prepared by a process comprising the steps of:

• (a) forming a polymer solution;
• (b) pouring the polymer solution into a plurality of porous tubes comprising a tubular module, each of said porous tubes having a cap at one end;
• (c) capping the other end of each of the porous tubes so that the ends of the tube are sealed from the ambient environment;
• (d) aligning the longitudinal axis of the tubular module in a substantially horizontal position;
• (e) rotating the aligned tubular module about its longitudinal axis at a speed of less than 60 revolutions per minute so that the polymer solution solvent evaporates through the porous wall tubes to provide a polymer film having a uniform thickness on the inside surface of the porous wall tubes, the polymer film and porous wall tubes thereby constituting the permeate filter system;
• (f) removing the caps at each end of each of the porous tubes.