Hollow membranes with capillary tubes, fluid treatment modules that use them and methods of manufacturing them

A method of manufacturing a fluid treatment module comprising the following steps:

• 1) preparing at least two composite membranes by forming, on the external surfaces and in the pores of a membrane matrix comprising rectilinear open pores arranged between its two external surfaces, a coating of organic polymer by in situ polymerization of a monomer precursor of the polymer to create capillary channels within the membrane matrix,
• 2) forming, from the composite membranes and panels of porous material, a stack in which each composite membrane is arranged between two panels of porous material,
• 3) forming sealed joints between the composite membranes and the porous panels on the lateral faces of the stack,
• 4) making openings in the sealed joint only at the level of the composite membranes, and for each composite membrane only on two different lateral faces of the stack,
• 5) introducing through these openings a first reactant capable of destroying the material forming the membrane matrix of the composite membranes without affecting the polymer covering the surfaces and the pores of the membrane matrix, in order to obtain a stack of hollow membranes and panels of porous material in which the internal cavities of the hollow membranes are accessible on two lateral faces of the stack.