Patent ID: 6324898
Filing Date: 2001-12-04
Classification: B01D,G01N

Abstract:
A method of testing the integrity of membranes used to filter a liquid feed applied to a first side of the membranes to produce a liquid permeate at a second side of the membranes comprising the steps of:a) providing a membrane unit to be tested;(b) providing an air collection vessel in fluid communication with the second side of the membranes of the membrane unit;(c) stopping filtration through the membrane unit;(d) exposing the first side of the membranes in the membrane unit to air;(e) retaining liquid permeate at least between the second side of the membranes and the air collection vessel;(f) creating a transmembrane pressure from the first side of the membranes to the second side of the membranes for a selected period of time, the transmembrane pressure being sufficient to pass air into the liquid permeate between the second side of the membranes and the air collection vessel through a potential defect of concern in the membranes but not sufficient to exceed the bubble point of a membranes without defects;(g) separating air which passes through the membrane unit during at least a part of step (f) above from the retained liquid permeate and collecting the separated air in the air collection vessel;(h) measuring the volume of air collected in step (g) above; and,(i) interpreting whether the measured volume of air indicates that there is a defect in the membranes of the membrane unit.