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Water intrusion test for filters

  • US 5,786,528 A
  • Filed: 09/10/1996
  • Issued: 07/28/1998
  • Est. Priority Date: 09/10/1996
  • Status: Expired due to Term
First Claim
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1. A method for determining the integrity and/or pore size distribution of a porous filter by water intrusion flow testing which comprises:

  • positioning said filter in a test cell,introducing into said test cell a liquid a liquid which does not instantaneously filter into said test cell, the volume of said liquid being sufficient to surround said filter;

    providing an enclosed gas space in fluid communication with said liquid, the combination of the volume of said gas space, the volume of said liquid surrounding said filter device and the volume of liquid within said filter device defining a system volume;

    applying a pressure through said gas space to produce a composite liquid flowrate in said test cell consisting of a first flow component representative of a change in volume of said filter due to structural changes of said filter resulting form the compressive effects of applied pressure and a second flow component representative of liquid intrusion into and leaking from the pores of said filter;

    calculating the cumulative volume of said gas space while pressure is applied to said filter to derive a value of said system volume at any time while pressure is applied;

    determining an adjusted composite liquid flowrate measurement from said derived value of said system volume which is essentially solely indicative of said second flow component; and

    correlating said adjusted composite liquid flowrate with a pre-determined flowrate value indicative of known integral and/or rated pore size filters whereby the integrity and/or pore size distribution of said filter under test may be accurately determined.

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