Composite membranes

A composite membrane comprising an inorganic support composed of woven or non-woven fibres and having interstices of diameter greater than 5 .mu.m and length less than ten times their diameters, and porous inorganic films of sintered non-metallic particles carried by the support and bridging the interstices thereof, the films having pore sizes up to 2 .mu.m, wherein the membrane is corrugated.

A method of making a composite membrane, by providing an inorganic support composed of woven or non-woven metal fibres and having interstices of diameter greater than 5 .mu.m and less than ten times their diameter, pre-treating the support to improve its coating properties by contacting it with a solution containing phosphate anions, applying to the pretreated support a suspension of sinterable inorganic non-metallic particles, so as to create films bridging the interstices thereof, and drying and heating the films to partly sinter the particles the films having pore sizes up to 2 .mu.m.

In a filtration device wherein a filter membrane and a spacer sheet are arranged in a spiral format on a product tube, the improvement which consists is that the filter membrane is a composite membrane comprising an inorganic support composed of woven or non-woven fibres and having interstices of diameter greater than 5 .mu.m and length less than ten times their diameters, and porous inorganic films of sintered non-metallic particles carried by the support and bridging the interstices thereof, the films having pore sizes up to 2 .mu.m.

In a filtration device wherein two filter membranes and an interposed spacer sheet are arranged in a spiral format on a product tube, the improvement which consists is that one or each filter membrane is a composite membrane comprising an inorganic support composed of woven or non-woven fibres and having interstices of diameter greater than 5 .mu.m and length less than ten times their diameters, and porous inorganic films of sintered non-metallic particles carried by the support and bridging the interstices thereof, the films having pore sizes up to 2 .mu.m.

In a filtration device wherein two filter membranes are arranged in a spiral format on a product tube, one or each filter membrane being corrugated, the improvement which consists is that one or each filter membrane is a composite membrane comprising an inorganic support composed of woven or non-woven fibres and having interstices of diameter greater than 5 .mu.m and length less than ten times their diameters, and porous inorganic films of sintered non-metallic particles carried by the support and bridging the interstices thereof, the films having pore sizes up to 2 .mu.m.

In a filtration device wherein a flat or corrugated filter membrane is arranged in a plate and frame format, the improvement which consists is that the filter membrane is a composite membrane comprising an inorganic support composed of woven or non-woven fibres and having interstices of diameter greater than 5 .mu.m and length less than ten times their diameters, and porous inorganic films of sintered non-metallic particles carried by the support and bridging the interstices thereof, the films having pore sizes up to 2 .mu.m.

In a filtration device comprising a stack of corrugated filter membrane plates arranged so that the corrugations of alternate plates are perpendicular and sealed to form separated feed and permeate channels and integrally sealed into a housing having an inner vessel wall and end plates, the improvement which consists in that the filter membrane is a composite membrane comprising an inorganic support composed of woven or non-woven fibres and having interstices of diameter greater than 5 .mu.m and length less than ten times their diameters, and porous inorganic films of sintered non-metallic particles carried by the support and bridging the interstices thereof, the films having pore sizes up to 2 .mu.m.