Emd Millipore Corporation

David Nhiem

Salvatore Giglia

Gabriel Tkacik

Sherry Ashby Leon

Mikhail Kozlov

Philip M Goddard

Sal Giglia

Onur Y Kas

A fluid filtration device containing a composite filter media having a coarse porous polymeric nonwoven interlayer located between first and second polymeric fiber containing filter mats. The fiber diameters of the fibers in the first and second filter mats are different from each other, and each filter mat has a different pore size rating. The first and second polymeric fibers in the filter mats can be electrospun nanofibers. The interlayer has a coarser pore size when compared to the either the first or second filter mats, such that the resulting composite media has an increased dirt holding capacity compared to filter layers that are layered directly over each other without the presence of a coarse interlayer therebetween.

Filter structure with enhanced dirt holding capacity

A method of integrity testing a porous material is disclosed, providing a porous material suitable for filtration to be tested, said porous material having a first surface and a second surface; wetting said porous material with a wetting liquid; providing a gas stream comprising at least first and second gases humidified with said wetting liquid below the saturation vapor pressure of said wetting liquid and wherein said humidified gas stream has a humidity of 50-99%; introducing said gas stream to said first surface of said porous material; causing said first and second gases to flow through said porous material; measuring the concentration of at least one of said first and second gases in the permeate stream exiting said second surface of said porous material; and comparing the measured concentration to a predetermined concentration.

Enhanced stability filter integrity test

A composite liquid filtration platform including a composite filtration medium featuring an electrospun polymeric nanofiber layer collected on a porous membrane. When in use, the porous membrane acts as a prefilter used upstream from the polymeric nanofiber layer to remove particles from a liquid stream flowing through the composite filtration structure. The nanofiber layer, positioned downstream from the porous membrane, is used as the retentive layer for critical filtration to provide biosafety assurance, and is responsible for capturing microorganisms like bacteria, mycoplasma or viruses. The composite liquid filtration platform provided herein exhibits permeability advantages over conventional porous membranes or nanofiber mats spun on coarse non-wovens.

Nanofiber containing composite membrane structures

A method of integrity testing porous materials that is non-destructive to the material being tested. The method includes humidifying the inlet gas stream to minimize or prevent the porous material from drying out. The inlet gas stream includes at least two gases, wherein one of the gases has a different permeability in liquid than the other, such as oxygen and nitrogen. The permeate gas stream may be subjected to a driving force such as reduced pressure to increase the flow of gases and reduce test time. Multiple porous materials can be integrity tested at the same time, such as by manifolding a plurality of them together. The integrity test is capable of detecting the presence of oversized pores or defects that can compromise the retention capability of the porous material.

A method of aerosol integrity testing of filters, capable of detecting single defects that are less than 20 &#x3bc;m in diameter, and even as small as 2 &#x3bc;m in diameter, in liquid sterilizing grade filters such as filter cartridges. The method challenges the filter in a dry state with a particle stream of aerosol particles of the appropriate size and in the appropriate concentration, such that at least one or more of the particles in the stream will penetrate a defective region or regions within the membrane but will not penetrate in the integral region of the membrane. Wetting of the filter is not required.

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Burlington, MA, United States of America

David Nhiem