The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 11, 1997
Filed:
Oct. 12, 1995
Peter J Degen, Huntington, NY (US);
John Mischenko, III, Amityville, NY (US);
Robert E Kesting, Sumner, WA (US);
Moira H Bilich, Massapequa, NY (US);
Trevor A Staff, Bronx, NY (US);
Pall Corporation, East Hills, NY (US);
Abstract
The present invention provides for the first time ultrafiltration/diafiltration membranes that are capable of excluding 0.02 .mu.m diameter, monodisperse, latex particles and are capable of being dried without loss of such ultrafiltration properties. A rapid, reliable method for integrity testing membranes also has now been discovered. The test has particular applicability to ultrafiltration membranes, although it may also be used for testing microfiltration membranes as well. In accordance with the method, referred to as the K.sub.UF method, the membrane to be tested is first thoroughly wetted with a wetting liquid that is capable of fully wetting the membrane; a displacing liquid is placed in contact with one side of the wetted membrane and increasing pressure is then applied to said displacing liquid; and the flow rate through said membrane is measured as a function of the applied pressure; wherein the displacing liquid is substantially insoluble in the wetting liquid and the interfacial tension between the two liquids is about 10.0 dynes/cm or less. A plot of the flow rate of liquid, per unit area of the membrane, through the membrane as a function of applied pressure can be made and a straight line may be drawn through the steep part of the resulting curve, using regression analysis, which will intersect the horizontal axis at a given pressure value, which is then the K.sub.UF value.