A method for removing silica from ultra pure water (UPW) comprises passing UPW through a filter comprising a microporous cationically charged membrane having an upstream surface and a downstream surface; and a porous asymmetric membrane having a first surface and an upstream portion and a downstream portion and a second surface, and a bulk between the first surface and the second surface including the upstream portion and the downstream portion, the porous asymmetric membrane having decreasing pore sizes in a direction from the first surface and the upstream portion to the downstream portion and the second surface, the second surface comprising a skin having a nanoporous average pore size, wherein the first surface of the porous asymmetric membrane contacts the downstream surface of the microporous cationically charged membrane; the method including passing the UPW through the microporous cationically charged membrane before passing the UPW through the porous asymmetric membrane.

An air filter medium includes a first porous PTFE membrane and a second porous PTFE membrane. The air filter medium has a first main surface and a second main surface, and the first porous PTFE membrane and the second porous PTFE membrane are arranged so that an air flow moving from the first main surface to the second main surface passes through the first porous PTFE membrane and subsequently through the second porous PTFE membrane. A proportion of areas occupied by the plurality of nodes on a surface of the first porous PTFE membrane is in the range of 1.5 to 3.0% and an average of the areas of the plurality of nodes is 200 μm2 or more.

An air filter medium includes a first porous PTFE membrane and a second porous PTFE membrane. The air filter medium has a first main surface and a second main surface, and the first porous PTFE membrane and the second porous PTFE membrane are arranged so that an air flow moving from the first main surface to the second main surface passes through the first porous PTFE membrane and subsequently through the second porous PTFE membrane. A proportion of areas occupied by the plurality of nodes on a surface of the first porous PTFE membrane is in the range of 1.5 to 3.0% and an average of the areas of the plurality of nodes is 200 μm2 or more.

Provided is a filtration device that can increase a filtration treatment amount by suppressing clogging of a filtration filter. A filtration device according to the present invention includes: a filtration filter that includes a filter that filters a filtration target contained in a fluid, and a frame that holds the filter; a support structure that holds the frame such that the filter is bent; and a fluid supplying unit that supplies the fluid with the filter being in a bent state.

This gas purification filter unit (10) is provided with: a first elimination unit (11) that eliminates gas component impurities among the impurities contained in ozone generated from an ozone generating device; and a second elimination unit (12) that is disposed at a later stage than the first elimination unit and that further eliminates solid particulate impurities from among the impurities from which the gas component has been eliminated. Ozone containing impurities are caused to flow in from the inflow end (10a) of such a gas purification filter unit (10) and is passed through the first elimination unit (11) and second elimination unit (12), and thus ozone from which impurities have been eliminated is discharged from an outflow end (10b).

This gas purification filter unit (10) is provided with: a first elimination unit (11) that eliminates gas component impurities among the impurities contained in ozone generated from an ozone generating device; and a second elimination unit (12) that is disposed at a later stage than the first elimination unit and that further eliminates solid particulate impurities from among the impurities from which the gas component has been eliminated. Ozone containing impurities are caused to flow in from the inflow end (10a) of such a gas purification filter unit (10) and is passed through the first elimination unit (11) and second elimination unit (12), and thus ozone from which impurities have been eliminated is discharged from an outflow end (10b).

A filter assembly consists of four principal components. The principle components include a top housing containing the means to fasten in a leak proof manner to a valved top of a sport bottle; a base housing; an outer independent charged layered membrane filter; and an inner independent charged layered membrane filter. Each charged layered filter is in a cylindrical form with pleats.

A filter assembly consists of four principal components. The principle components include a top housing containing the means to fasten in a leak proof manner to a valved top of a sport bottle; a base housing; an outer independent charged layered membrane filter; and an inner independent charged layered membrane filter. Each charged layered filter is in a cylindrical form with pleats.

Embodiments provide a filter with a generally rectangular, non-cylindrical profile. The filter may have multiple pleat packs positioned between pleat covers that define regions and flow channels in a cavity of the filter body. The pleat covers have openings that allow a fluid to flow through the multiple pleat packs via parallel flows or series flows. End caps bonded to the body define flow passages for directing the fluid from an inlet to an outlet via the pleat packs for series or parallel filtration. The pleat packs may be made of the same or different materials and may be configured with the same or different heights based on flow requirements. A cage or a separator may be positioned between the pleat packs. The pleat packs may be made of a continuous pleated membrane with bridges defining a space between the pleat packs to accommodate the cage or separator.

A membrane capsule for biological and chemical separations comprising a cassette comprising an upper surface and a lower surface adjoined by a cassette sidewall, an inlet and an outlet located on the upper and lower surfaces of the cassette, tubes fluidly connected to the inlet and the outlet, holes or slots in the tubes to facilitate separation, and a membrane wrapped, pleated, and/or spiral wound around each of the tubes. Methods of separation comprising flowing fluid flow through the inlet of the membrane capsule, allowing the fluid to permeate through the holes or slots of the tubes, separating biological and/or non-biological substances, collecting the fluid within a reservoir, and draining fluid from the reservoir.