Current flow integrity test
AssigneeMillipore Corporation
InventorsStephen Proulx, John L. Burns, Jr., Scott Emory, Richard W. Gray, Frank M. Lentine
Life of this patent
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Abstract
A new method and apparatus is described for conducting an integrity test on porous membranes and membrane filters and for conducting a pore-size characterization of membrane. The method and apparatus apply to membrane integrity tests and pore-size characterizations which are based on the dependence on the pore size of the pressure required to intrude a non-wetting, electrically conductive liquid into and through the pores. Electrical-measurement methods are described for identifying the pressure at which intrusion occurs.
Claims48
The process for determining porosity characteristic of an electrically nonconductive ultrafiltration or microporous membrane which comprises:
- contacting a first surface of said membrane with a second liquid which does not wet said membrane,
- contacting a second surface of said membrane with a second liquid which does not wet said membrane,
- increasing pressure on said first liquid to cause said first liquid to intrude said membrane,
- measuring change in electrical conductivity across said membrane,
- and correlating said change of electrical conductivity across said membrane with said porosity characteristic.
The process for determining a porosity characteristic in an electrically nonconductive ultrafiltration or microporous membrane which comprises:
- contacting a first surface of said membrane with an electrically conductive first liquid which does not wet said membrane,
- contacting a second surface of said membrane with a second liquid which does not wet said membrane,
- increasing pressure on said first liquid to cause said first liquid to intrude said membrane,
- measuring change in electrical conductivity of said second liquid, and
- correlating said change of electrical conductivity in said second liquid with said porosity characteristic.
The process for determining the presence of defects in an electrically nonconductive ultrafiltration or microporous membrane which comprises:
- contacting a first surface of said membrane with an electrically conductive first liquid which does not wet said membrane
- contacting a second surface of said membrane with a second liquid which does not wet said membrane,
- increasing pressure on said first liquid to a pressure less than a characteristic intrusion pressure of said membrane,
- and measuring change in electrical conductivity of said second liquid.
The process for determining the presence of defects in an electrically nonconductive ultrafiltration or microporous membrane which comprises:
- contacting a first surface of said membrane with an electrically conductive first liquid which does not wet said membrane:
- contacting a second surface of said membrane with a second liquid which does not wet said membrane,
- increasing pressure on said first liquid to a pressure less than a characteristic intrusion pressure of said membrane, and
- measuring change in electrical conductivity across said membrane.
The process for determining a porosity characteristic of an electrically nonconductive ultrafiltration or microporous membrane which comprises:
- contacting a first surface of said membrane with an electrically conductive first liquid,
- contacting a second surface of said membrane with a second liquid, said porous membrane containing a third liquid which prevents said first liquid and said second liquid from wetting said membrane,
- increasing pressure on said first liquid to cause said first liquid to intrude said membrane,
- measuring change in electrical conductivity across said membrane,
- and correlating said change of electrical conductivity across said membrane with said porosity characteristic.
The process for determining a porosity characteristic in an electrically nonconductive ultrafiltration or microporous membrane which comprises:
- contacting a first surface of said membrane with an electrically conductive first liquid,
- contacting a second surface of said membrane with a second liquid, said porous membrane containing a third liquid which prevents said first liquid and said second liquid from wetting said membrane,
- increasing pressure on said first liquid to cause said first liquid to intrude said membrane,
- measuring change in electrical conductivity of said second liquid, and correlating said change of electrical conductivity in said second liquid with said porosity characteristic.
The process for determining the presence of defects in an electrically nonconductive ultrafiltration or microporous membrane which comprises:
- contacting a first surface of said membrane with an electrically conductive first liquid,
- contacting a second surface of said membrane with a second liquid, said porous membrane containing a third liquid which prevents said first liquid and said second liquid from wetting said membrane,
- increasing pressure on said first liquid to a pressure less than a characteristic intrusion pressure said membrane, and
- measuring change in electrical conductivity of said second liquid.
The process for determining the presence of defects in an electrically nonconductive ultrafiltration or microporous membrane which comprises:
- contacting a first surface of said membrane with an electrically conductive first liquid,
- contacting a second surface of said membrane with a second liquid, said porous membrane containing a third liquid which prevents said first liquid and said second liquid from wetting said membrane,
- increasing pressure on said first liquid to a pressure less than a characteristic intrusion pressure of said membrane, and
- measuring change in electrical conductivity across said membrane.
Dependencies are inferred from the claim text.