Hollow fiber membrane, hollow fiber membrane module, and water purifier

• US 20030052055A1
• Filed: 11/01/2002
• Published: 03/20/2003
• Est. Priority Date: 03/08/2001
• Status: Abandoned Application

• Current Assignee: Toray Industries Incorporated
• Original Assignee: Toray Industries Incorporated
• Inventors: Abe, Hiroyoshi, Akamatsu, Hiroharu
• Application Number:
  US10/275,097
• Publication Number:
  US 20030052055A1
• Time in Patent Office: Days
• US Class Current: 210/500.23
• CPC Class Codes: B01D 2323/12 Specific ratios of components used
• CPC Class Codes: B01D 63/02 Hollow fibre modules
• CPC Class Codes: B01D 63/024 with a single potted end
• CPC Class Codes: B01D 63/0241 being U-shaped
• CPC Class Codes: B01D 67/0083 Thermal after-treatment
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 69/08 Hollow fibre membranes manufacture of hollow fibres D01D5/24, D01F1/08
• CPC Class Codes: B01D 71/68 Polysulfones; Polyethersulfones
• CPC Class Codes: C02F 1/444 by ultrafiltration or microfiltration

Abstract

A hollow fiber membrane, wherein an inner diameter (Id) is within the range of 100 to 200 μm, the ratio (Mt/Id) of a wall thickness (Mt) to the inner diameter (Id) is the range of 0.9 to 1.1, a bubble point (Bp) is at least 0.5 MPa, and the ratio (Di/Do) of the maximum major axis (Di) of the pores existing in the layer of up to 10 μm thick from an inner surface to the maximum major axis (Do) of the pores existing in the layer of up to 10 μm thick from an outer surface is within the range of 10.0 to 15.0; a hollow fiber membrane module formed of the hollow fiber membranes; and a water purifier formed of the hollow fiber membrane module.

Claims

1. A hollow fiber membrane, wherein an inner diameter (Id) is within the range of 100 to 200 μ

m, the ratio (Mt/Id) of a wall thickness (Mt) to the inner diameter (Id) is the range of 0.9 to 1.1, a bubble point (Bp) is at least 0.5 MPa, and the ratio (Di/Do) of the maximum major axis (Di) of the pores existing in the layer of up to 10 μ

m thick from an inner surface to the maximum major axis (Do) of the pores existing in the layer of up to 10 μ

m thick from an outer surface is within the range of 10.0 to 15.0.

2. A hollow fiber membrane, according to claim 1, wherein the hollow fiber membrane is made of a polysulfone and polyvinyl pyrrolidone, and the rate of the weight of polyvinyl pyrrolidone based on the weight of the hollow fiber membrane is 1.0 to 3.0 wt %.

3. A hollow fiber membrane module that comprises a plurality of hollow fiber membranes fastened to a support, in which the respective hollow fiber membranes are opened on one-end side and sealed on the other-end side in a mode where the respective hollow fiber membranes are paralleled in one certain direction, or in which the respective hollow fiber membranes are opened on both end sides in a mode where the respective hollow fiber membranes are paralleled in one certain direction and subsequently turned and paralleled in the opposite direction, characterized in that said hollow fiber membranes are the hollow fiber membranes as set forth in claim 1 or 2.

4. A hollow fiber membrane module, according to claim 3, wherein in the case where raw water containing 20 ppm of a dust having particle sizes of 5.0 μ

m and less is forced to flow at a pressure of 0.41 MPa for 1.5 minutes and subsequently suspended for 0.5 minute, and where the flow and suspension are repeated till the flow declines to 25% of the initial flow, the turbidity of the purified water becomes 0.15 or less, and wherein the occurrence rate of the hollow fiber membranes having a short diameter ratio of 0.70 or less at the outer circumference after the flow and suspension have been repeated till the turbidity of the purified water becomes 0.15 is 0.1% or less.

5. A hollow fiber membrane module, according to claim 3, wherein in the case where raw water having a colon bacilli count (RWBcn) of 10⁷ to 10⁸ CFUs/100 ml and containing 20 ppm of a dust having particle sizes of 5.0 μ

m and less is forced to flow at a pressure of 0.41 MPa for 4 minutes and subsequently suspended for 36 minutes, and where the flow and suspension are repeated 12 times, the colon bacilli count (RWBcn) of the raw water and the colon bacilli count (FWBcn) of the purified water satisfy the following formula;

LOG₁₀(RWBcn)−

LOG₁₀(FWBcn)≧

6.0.

6. A hollow fiber membrane module, according to claim 3, wherein in the case where raw water having a Pseudomonas count (RWPmn) of 10⁷ to 10⁸ CFUs/100 ml and containing 20 ppm of a dust having particle sizes of 5.0 Fm and less is forced to flow at a pressure of 0.41 MPa for 4 minutes and subsequently suspended for 36 minutes, and where the flow and suspension are repeated 12 times, the Pseudomonas count (RWPmn) of the raw water and the Pseudomonas count (FWPmn) of the purified water satisfy the following formula:

LOG₁₀(RWPmn)−

LOG₁₀(FWPmn)≧

6.0.

7. A water purifier, which is composed of a housing, a hollow fiber membrane module contained in the housing, an inlet of raw water into said hollow fiber membrane module, provided in said housing, and an outlet of purified water filtered by said hollow fiber membrane module, provided in the housing, characterized in that said hollow fiber membrane module is the hollow fiber membrane module as set forth in any one of claims 3 through 6.