Provided is a porous membrane having a high blocking performance suited for filtration application as well as being excellent in water permeability performance, which is capable of providing stable filtering operation over a long period of time. The porous membrane has a cross-sectional pore size index of 40 or more in a region where a membrane thickness position ranges from 0.1 to 0.2 within the membrane thickness which is normalized by defining one surface position as 0 and the other surface position as 1 and divided into ten regions in the membrane thickness direction, the cross-sectional pore size index being calculated by: Cross-Sectional Pore Size Index=(Cross-Sectional Pore Size in the Range)/(Pore Size of the One Surface).

The present invention relates to a hollow fiber membrane in which the thickness L of a spherical structure layer is 60-500 ?m (inclusive), the spherical structure layer has a first surface and a second surface, the average diameter Da.sub.1 of the spherical structure in a region Sa.sub.1 10 ?m or less from the first surface and the average diameter db.sub.2 of the spherical structure in a region Sb.sub.2 10-20 ?m from the second surface satisfy the relational expression Da.sub.1>db.sub.2, and the spherical structure satisfies certain parameters.

The present invention is related to a method for fabricating multilayer singlebore membranes (10) or multilayer multibore membranes (20) for ultrafiltration applications including the following method steps: (a) feeding at least a material of a substrate (12), at least one material of a functional layer (14, 15) and a bore fluid (36) to a spinneret (30) simultaneously; (b) forming said membranes (10, 20) as a tube-like string (54) in a one-step process in said spinneret (30); (c) thereby assigning a functionality to said functional layer (14, 15) applied on at least one surface (13, 17) of said substrate (12). The invention is also related to a spinneret (30) for fabricating multilayer singlebore membranes (10) or multilayer multibore membranes (20), using the inventive method, and to a system comprising such a spinneret (30).

A hollow fiber membrane that is a hollow fiber type semipermeable membrane, wherein a Raman value is 70% or more, and the Raman value is a ratio of a minimum value to a maximum value of peak intensities, which are intensities of maximum peaks in each of multiple Raman spectra obtained by Raman spectroscopy at multiple points in a membrane thickness direction of a transverse cross-section of the hollow fiber membrane in a state of being swollen with water.

A hollow fiber membrane is formed by embedding a braid having a spiral open weave of monofilaments only, to avoid a whiskering problem. The open weave is characterized by contiguous, circumferential, rhomboid-shaped areas of polymer film separated by monofilaments. When the braid is supported on a plasticized PVA cable having a scalloped periphery, the braid can be infiltrated with membrane polymer which, when coagulated, embeds the braid positioning it around the lumen. The embedded spiral weave, free of any circumferentially constricting monofilament, allows the membrane to be biaxially distensible. The membrane has give not only in the axial or longitudinal direction but also in the radial direction. Give in the radial direction permits soiled membranes to be backwashed under higher pressure than in a comparable braid which is not radially distensible.

The present invention provides a carbon membrane for fluid separation with which a high-pressure fluid can be separated and purified and which has excellent pressure resistance and is less apt to be damaged. The present invention relates to a carbon membrane for fluid separation, including: a core layer which has a co-continuous porous structure; and a skin layer which has substantially no co-continuous porous structure and is formed around the core layer.

A fluid separation apparatus comprising a fluid separation membrane is provided. The fluid separation apparatus comprises a fluid separation membrane extending in one direction and having a cross-section with a closed curve shape, wherein the fluid separation membrane has a thickness of 0.1 mm to 2 mm, and an outer diameter of 60 mm to 360 mm when the cross-section is adjusted to be circular.

A hollow fiber membrane is formed by embedding a braid having a spiral open weave of monofilaments only, to avoid a whiskering problem. The open weave is characterized by contiguous, circumferential, rhomboid-shaped areas of polymer film separated by monofilament. When the braid is supported on a plasticized PVA cable having a scalloped periphery, the braid can be infiltrated with membrane polymer which, when coagulated, embeds the braid positioning it around the lumen. The embedded spiral weave, free of any circumferentially constricting monofilament, allows the membrane to be biaxially distensible. The membrane has give not only in the axial or longitudinal direction but also in the radial direction. Give in the radial direction permits soiled membranes to be backwashed under higher pressure than in a comparable braid which is not radially distensible.

A separator element for obtaining molecular and/or particulate separation by tangential flow of a fluid medium for treatment into a filtrate and a retentate, the element comprising a structure (2) of at least two porous rigid columns (3) made of the same material, positioned side by side to define outside their outside walls a volume (4) for recovering the filtrate, each column (3) presenting internally at least one open structure (5) for passing a flow of the fluid medium, opening out in one of the ends of the porous column for inlet of the fluid medium for treatment and in the other end for outlet of the retentate. The element is a single-piece rigid structure (2) made as a single piece that is uniform and continuous throughout, without any bonds or exogenous additions.

Disclosed is a membrane humidifier for a fuel cell, comprising multi-channel hollow fiber membranes having a plurality of channels in various sizes, thus allowing humidifying performance to be maintained in the case of a high rate of flow and to be decreased in the case of a low rate of flow, and thereby preventing flooding. The membrane humidifier for a fuel cell, according to the present invention, comprises: a middle case in which a plurality of hollow fiber membranes are accommodated; a cap case coupled to the middle case; and a fixing unit in which ends of the plurality of hollow fiber membranes are potted, wherein a plurality of channels are formed in each of the hollow fiber membranes, and the difference between the biggest and smallest inner diameters among the inner diameters of the plurality of channels is 30-600 m.