Patent ID: 7306105
Filing Date: 2007-12-11
Classification: B01D

Abstract:
1. A composite porous membrane comprising a braid, and a membrane material, wherein said membrane material comprises a first porous layer having an inner surface, an outer surface, and a first thickness, and a second porous layer having an inner surface, an outer surface, and a second thickness, the first porous layer is arranged on the outer surface of the braid and the second porous layer is arranged on the first porous layer, the first porous layer includes a first dense layer with a thickness less than the first thickness and the first dense layer has an average pore diameter in the range of 0.2 μm to 1 μm, the second porous layer includes a second dense layer with a thickness less than the second thickness and the second dense layer has an average pore diameter in a range of 0.1 μm to 0.8 μm, and at least one of said first and second dense layers is located 0.1 μm to 50 μm inside from the outer surface of its respective porous layer.