Abstract: A method of predicting logarithmic reduction values for a membrane filtration system having a filtrate flow portion and a bypass flow portion relative to a filtrate permeable membrane with stable input gas flow comprising: determining the filtrate flow rate through the membrane under the action of an applied test pressure, determining the membrane bypass flow rate using integrity test measurements and estimating the logarithmic reduction value using the ratio of determined filtrate flow rate and determined bypass flow rate. Methods of testing the integrity of a porous membrane are also disclosed.

Abstract: An improved microporous, modular filter structure assembled from replaceable filter cartridges (25) housed within a filter cartridge assemby (10) connected at opposed ends by means of symmetrical headers (41). The headers include a tube within a tube structure whereby they are adapted to conduct first and second fluids independently to both adjacent, like interconnected headers and into and out of filter cartridges (25) to which each header (41) is connected at both ends of each cartridge. Manifolds (100, 101) include a similar tube within a tube structure which allows them to be connected to the ends of rows of interconnected headers (41) whereby a modular filter bank can be constructed of indefinite dimension and capacity.

Abstract: A manifold structure for connecting rows of cartridges (100) to adjacent like rows of cartridges (100). The manifold structure includes a first fluid passage (153, 183) adapted to pass either feed or filtrate through the body of the manifold structure, a second fluid passageway (169, 197) adapted to be coupled to a first passageway of a filter cartridge to provide fluid communication between the cartridge and the first passageway, a third fluid passageway (167, 199) adapted to be coupled to a second passageway of the filter cartridge to provide fluid communication between the cartridge and the first passageway; only one of the second fluid passageway or the third fluid passageway being enabled for fluid communication at any one time.