US2005051479A1PendingUtilityA1

Hollow fiber membrane and braided tubular support therefor

44
Priority: Jul 1, 1997Filed: Sep 14, 2004Published: Mar 10, 2005
Est. expiryJul 1, 2017(expired)· nominal 20-yr term from priority
Inventors:Mailvaganam MahendranKenneth P. GoodboyLuigi Fabbricino
B01D 69/1071B01D 2325/0233B01D 69/1411B01D 67/0011B01D 69/1216B01D 71/34B01D 69/08B01D 2325/40B01D 2325/04B01D 69/02C08K 9/02
44
PatentIndex Score
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Claims

Abstract

An asymmetric membrane comprising a tubular polymer film in combination with a tubular braid on which the film is supported, requires the braid be macroporous and flexible, yet sufficiently strong to withstand continuous flexing, stretching and abrasion during use for microfiltration (MF) or ultrafiltration (UF). The specifications for a braid of a long-lived membrane are provided. A membrane is formed by supporting a polymer film in which particles of calcined α-alumina are dispersed, on the defined tubular braid.

Claims

exact text as granted — not AI-modified
1 . A separation membrane comprising, 
 (a) a tubular braid support for a hollow fiber separation membrane made from 16 to 60 separate yarns, each yarn being between 150 and 400 denier, the tubular braid support having an outside diameter between 1.5 and 2.5 mm and a wall thickness greater than 0.2 mm and less than 1.0 mm, the tubular braid support having at least 30 picks per inch; and,    (b) a porous substance attached to the support, the porous substance covering the outer circumferential surface of the support, the porous substance being between 0.05 and 0.3 mm thick beyond the outer surface of the support and having pores suitable for use as a separation membrane.    
     
     
         2 . The membrane of  claim 1  wherein the yarns are shrunken to a stable length before the porous substance is attached to the support and the support with shrunken yarns has an extension at break of at least 10%.  
     
     
         3 . The membrane of  claim 1  wherein the support has a pre-shrunk length that is at least 1% less than an un-shrunk length of the support.  
     
     
         4 . The membrane of  claim 3  wherein the support has a pre-shrunk length that is between 1% and 20% less than an un-shrunk length of the support.  
     
     
         5 . The membrane of  claim 4  wherein the support has a pre-shrunk length that is between 1% and 8% less than an un-shrunk length of the support.  
     
     
         6 . The membrane of  claim 1  wherein the support is flexible and macroporous.  
     
     
         7 . The membrane of  claim 2  wherein the support has an extension at break of at least 20%.  
     
     
         8 . The membrane of  claim 1  wherein the air permeability of the support without the porous substance attached is at least 1 cc/sec/cm 2  at 1.378 kPa.  
     
     
         9 . The membrane of  claim 8  wherein the air permeability of the support without the porous substance attached is less than about 10 cc/sec/cm 2  at 1.378 kPa.  
     
     
         10 . The membrane of  claim 1  wherein the support is not embedded in the porous substance.  
     
     
         11 . The membrane of  claim 1  wherein the support is woven with from 1 to 3 multifilament ends.  
     
     
         12 . The membrane of  claim 11  wherein the support comprises a multifilament made with from 40 to 100 filaments, each filament being from 3 to 6 denier.  
     
     
         13 . The membrane of  claim 1  wherein the yarns are woven in a pattern selected from Diamond, Regular or Hercules.  
     
     
         14 . The membrane of  claim 1  wherein the support comprises a tubular braid woven with yarns having a plurality of multifilament ends, and the ends are non-plied in each yarn but lie linearly adjacent each other until taken up to form the braid.  
     
     
         15 . The membrane of  claim 1  wherein the porous substance has pores of a size suitable for use as a microfiltration or ultrafiltration membrane.  
     
     
         16 . The membrane of  claim 1  wherein the support has a moisture regain of 0.2% to 7% by weight.  
     
     
         17 . A separation membrane comprising, 
 (a) a support for a hollow fiber separation membrane made from yarns braided into a tube, each yarn being between 200 and 400 denier, with from 16 to 60 carriers; and,    (b) a porous substance attached to and covering the outer circumferential surface of the support and having pores suitable for use as a separation membrane, wherein, the support has at least 36 crosses per inch, an outside diameter of between 1.5 mm and 2.5 mm and a wall thickness of more than 0.15 mm and less than 0.5 mm.    
     
     
         18 . The membrane of  claim 17  wherein the support comprises at least 16 separate yarns and is woven with from 1 to 3 multifilament ends.  
     
     
         19 . The membrane of  claim 18  wherein the support comprises a multifilament made with from 40 to 100 filaments, each filament being from 3 to 6 denier.  
     
     
         20 . The membrane of  claim 17  wherein the yarns are woven in a pattern selected from Diamond, Regular or Hercules.  
     
     
         21 . The membrane of  claim 17  wherein the support comprises a tubular braid woven with yarns having from 1 to 3 non-plied multifilament ends.  
     
     
         22 . The membrane of  claim 17  wherein the air permeability of the support without the porous substance attached is less than about 10 cc/sec/cm 2  at 1.378 kPa.  
     
     
         23 . The membrane of  claim 17  wherein the yarns are pre-shrunken to a stable length.  
     
     
         24 . The membrane of  claim 17  wherein the support has an extension at break of at least 10%.  
     
     
         25 . The membrane of  claim 17  wherein the support has a pre-shrunk length that is at least 1% less than an un-shrunk length of the support.  
     
     
         26 . The membrane of  claim 25  wherein the support has a pre-shrunk length that is between 1% and 20% less than an un-shrunk length of the support.  
     
     
         27 . The membrane of  claim 26  wherein the support has a pre-shrunk length that is between 1% and 8% less than an un-shrunk length of the support.  
     
     
         28 . The membrane of  claim 17  wherein the support is flexible and macroporous.  
     
     
         29 . The membrane of  claim 17  wherein the support has an extension at break of at least 20%.  
     
     
         30 . The membrane of  claim 17  wherein the porous substance is at least 0.05 mm thick from the outer surface of the support to the outside of the porous substance.  
     
     
         31 . The membrane of  claim 30  wherein the porous substance is between 0.05 mm and 3.0 mm thick beyond the outer surface of the support to the outside of the porous substance.  
     
     
         32 . The membrane of  claim 17  wherein the porous substance is less than 2.0 mm thick beyond the outer surface of the support to the outside of the porous substance.  
     
     
         33 . The membrane of  claim 17  wherein the support is not embedded in the porous substance.  
     
     
         34 . The membrane of  claim 17  wherein the porous substance has pores of a size suitable for use as a microfiltration or ultrafiltration membrane.  
     
     
         35 . The membrane of  claim 17  wherein the support has a moisture regain of 0.2% to 7% by weight.  
     
     
         36 . The membrane of  claim 1  wherein each yarn is on its own carrier.  
     
     
         37 . The membrane of  claim 17  wherein the support has a rough and uneven surface formed by the overlapping yarns.

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