Membrane filtration module with adjustable header spacing

Abstract

A membrane filtration device has a multiplicity of hollow fiber membranes, or fibers, unconfined in a shell of a module; a first header and a second header disposed in vertically spaced-apart relationship; said first header and said second header having opposed ends of each fiber sealingly secured therein, all open ends of said fibers open to a permeate-discharging face of at least one header; permeate collection means to collect said permeate, sealingly connected in open fluid communication with a permeate-discharging face of at least one of said headers; means to withdraw said permeate; said fibers, said headers and said permeate collection means together forming an integrated combination wherein said fibers are essentially vertically disposed and ends of individual fibers are potted in closely spaced-apart relationship in cured resin; with opposed faces at a fixed distance; each of said fibers having a length from 0.1% to less than 5% greater.

We claim:  
     
         1 . An apparatus for withdrawing permeate from a liquid, the apparatus comprising: 
 a multiplicity of hollow fiber membranes; and    a first header and a second header, the first and second headers having a displacement between them and the first and second headers having respective opposed ends of each membrane sealingly secured therein, the insides of the membranes open to a permeate collection means connected to at least one of the headers,    wherein the displacement between the first and second headers is adjustable in relation to the lengths of the fiber membranes such that, in use, the fiber membranes have a length that is between 0.1% and 5% greater than the displacement between the first and second headers.    
     
     
         2 . An apparatus according to  claim 1  further comprising a spacer means connectable to the headers and for fixing the displacement between the first and second headers.  
     
     
         3 . An apparatus according to  claim 2  wherein the spacer means is one of a wall, a frame-structure, a tube-structure and a trellis structure.  
     
     
         4 . An apparatus according to  claim 2  wherein the displacement between the first and second headers can be changed.  
     
     
         5 . An apparatus according to  claim 2  wherein the spacer means further comprises a number of mounting holes usable to change the displacement between the headers.  
     
     
         6 . An apparatus according to  claim 1  further comprising a spacer means connected to the headers, the connection between the spacer means and one of the headers further comprising mounting holes, mounting holes spaced apart such that: 
 there is available a first connection defining a first displacement between the first and second headers at which first displacement fiber membranes have a length that is 0.1% to 5% greater than the first displacement between the first and second headers; and  
 there is available a second connection defining a second displacement between the first and second headers usable after a period of use during which the membranes have shrunk at which second displacement the shrunk membranes have a length that is 0.1% to 5% greater than the second displacement between the first and second headers.  
 
     
     
         7 . An apparatus according to  claim 2  further comprising: 
 a plate connected to the spacer means, the plate including a number of mounting holes usable to connect a header to the spacer means.  
 
     
     
         8 . An apparatus according to  claim 2  wherein the mounting holes are spaced apart such that: 
 there is available a first connection between the first header and one of the mounting holes defining a first displacement between the first and second headers where the majority of the fiber membranes each have a length that is 0.1% to 5% greater than the first displacement between the first and second headers; and  
 after a period of use during which the membranes have shrunk, there is available a second connection between the first header and another one of the mounting holes defining a second displacement between the first and second headers where the membranes each have a length that is 0.1% to 5% greater than the second displacement between the first and second headers.  
 
     
     
         9 . A process for maintaining a desired length of the membranes relative to the displacement between the first and second headers of an apparatus according to  claim 1 , the process comprising: 
 spacing the headers at a first displacement between the first and second headers wherein the membranes have a length that is 0.1% to 5% greater than the first displacement between the first and second headers;    using the apparatus until the membranes shrink; and    changing the displacement between the first and second headers to a second displacement wherein the shrunk membranes have a length that is 0.1% to 5% greater than the second displacement between the first and second headers.    
     
     
         10 . A process for maintaining a desired length of hollow fiber membranes secured between first and second headers relative to the displacement between the first header and the second header, the process comprising: 
 spacing the headers at a first displacement between the first and second headers wherein the membranes have a length that is 0.1% to 5% greater than the first displacement between the first and second headers;    using the apparatus until the membranes shrink; and    changing the displacement between the first and second headers to a second displacement wherein the shrunk fiber membranes have a length that is 0.1% to 5% greater than the second displacement between the first and second headers.    
     
     
         11 . A process according to  claim 9  wherein the apparatus includes a spacer means and changing the displacement between the first and second headers to the second displacement further comprises: 
 releasing a connection between the first header and the spacer means, moving the first header relative to the spacer means; and  
 re-connecting the first header and the spacer means.  
 
     
     
         12 . A process according to  claim 11  wherein the connections are made through a series of mounting holes usable to support a plurality of displacements between the first and second headers.