Abstract: A method for manufacturing multiple channel membranes includes extruding a polymer solution through an extrusion nozzle wherein several needles are arranged through which a gas or liquid containing a coagulating agent is injected during extrusion, wherein the outer side of the extruded material is first brought into contact with a mild coagulation agent and subsequently with a strong coagulation agent. By using the method a membrane is obtained having parallel channels extending in extrusion direction, in which an active layer is situated in the channels, whereas the outer surface with respect to the active layer has no or hardly any resistance to flows of liquid. By using the method it is possible to make shapes, such as recessed portions, in the membrane circumference. Also disclosed is the use of such membranes in filtration and separation techniques.

Abstract: The invention relates to self-supporting capillary membranes which are longitudinally reinforced by continuous reinforcing fibres incorporated in the wall of the capillary membrane, which fibres extend in the longitudinal direction of the capillary membrane. The capillary membranes according to the invention have an improved ultimate tensile strength and a reduced elongation at break as a result of which capillary rupture caused by flow transverse to the capillary membranes occurs considerably fewer times.

Abstract: Device for filtering a liquid. The filter device is provided with at least two filter elements (8, 15) placed parallel to each other. A three-way cock (6, 13) is accommodated in the pipe (4, 5) to each filter element (8, 15) for connection of the inflow opening of each filter element (8, 15) to a mains system (3) for supplying the liquid with sufficient pressure to press the liquid through the filter device. The three-way cocks (6, 13) are mutually connected by a pipe (19). A drain (23) to a sewer is provided which has a closing device (21), which is connected to a branch point (26) of the pipe (19) via a pipe (20). A three-way cock (10, 17) is accommodated in the pipe (9, 16) of each filter element (8, 15) for connecting the outflow opening of each filter element (8, 15) to a mains system (12) of a user. The three-way taps (10, 17) are mutually connected by a pipe (24).