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 contact angle of the first porous PTFE membrane with water is in the range of 154° to 165°.

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 contact angle of the first porous PTFE membrane with water is in the range of 154° to 165°.

A module alignment element, and a filter capsule including the module alignment element, a method of filtering fluid using the filter capsule, and a system including the filter capsule, are disclosed.

A modular structure for a mitigating evaporative fuel emissions, such as for an automobile, is described. The structure may include a plurality of frames and membranes for flowing fuel vapor and reducing the emission of hydrocarbon therefrom. The structure may include flow guides that provide a meandering flow path for both the fuel vapor and a permeate. A flow guide providing parallel flow paths is also described.

A filter pleat pack of the present disclosure includes an air filter medium folded into pleats. The air filter medium includes a laminate of a polytetrafluoroethylene (PTFE) porous membrane and an air-permeable supporting member. When a cut surface of the filter pleat pack is observed, the cut surface being taken along a plane perpendicularly crossing a pleat line of the filter pleat pack, the PTFE porous membrane has a first converging portion, a split portion, and a second converging portion in this order in a direction in which the membrane extends. In the split portion, the PTFE porous membrane is split into a plurality of layers in a thickness direction of the membrane and the plurality of layers are spaced apart from each other. At the first converging portion and the second converging portion, the plurality of layers converge into one layer. The filter pleat pack of the present disclosure is a filter pleat pack for which a collection efficiency decrease resulting from pleating is reduced.

A filter pleat pack of the present disclosure includes an air filter medium folded into pleats. The air filter medium includes a laminate of a polytetrafluoroethylene (PTFE) porous membrane and an air-permeable supporting member. When a cut surface of the filter pleat pack is observed, the cut surface being taken along a plane perpendicularly crossing a pleat line of the filter pleat pack, the PTFE porous membrane has a first converging portion, a split portion, and a second converging portion in this order in a direction in which the membrane extends. In the split portion, the PTFE porous membrane is split into a plurality of layers in a thickness direction of the membrane and the plurality of layers are spaced apart from each other. At the first converging portion and the second converging portion, the plurality of layers converge into one layer. The filter pleat pack of the present disclosure is a filter pleat pack for which a collection efficiency decrease resulting from pleating is reduced.

A filter pleat pack of the present disclosure includes an air filter medium folded into pleats, wherein the air filter medium includes a laminate of a polytetrafluoroethylene (PTFE) porous membrane and an air-permeable supporting member, and the air filter medium has a shrinkage rate of 50% or more, the shrinkage rate being determined by a formula (d2−d1)/d2, where d1 is a smallest thickness of the PTFE porous membrane in a folding area of the air filter medium folded into pleats and d2 is a thickness of the PTFE porous membrane in a flat area of the air filter medium. The filter pleat pack of the present disclosure is a filter pleat pack for which a collection efficiency decrease resulting from pleating is reduced.

A filter pleat pack of the present disclosure includes an air filter medium folded into pleats, wherein the air filter medium includes a laminate of a polytetrafluoroethylene (PTFE) porous membrane and an air-permeable supporting member, and the air filter medium has a shrinkage rate of 50% or more, the shrinkage rate being determined by a formula (d2−d1)/d2, where d1 is a smallest thickness of the PTFE porous membrane in a folding area of the air filter medium folded into pleats and d2 is a thickness of the PTFE porous membrane in a flat area of the air filter medium. The filter pleat pack of the present disclosure is a filter pleat pack for which a collection efficiency decrease resulting from pleating is reduced.

Described are liquid-flowable, porous polyethylene filter membranes that include two opposing sides and that have an asymmetric pore structure; filter components and filters that include this type of porous polyethylene filter membrane; methods of making the porous polyethylene filter membranes, filter components, and filters; and methods of using a porous polyethylene filter membrane, filter component, or filter, to filter a fluid such as a liquid chemical to remove unwanted material from the fluid.

Described herein are fluid treatment devices for use in tangential flow filtration, comprising a housing unit and a composite material, wherein the composite material comprises: a support member comprising a plurality of pores extending through the support member; and a non-self-supporting macroporous cross-linked gel comprising macropores having an average size of 10 nm to 3000 nm, said macroporous gel being located in the pores of the support member. The invention also relates to a method of separating a substance from a fluid, comprising the step of placing the fluid in contact with an inventive device, thereby adsorbing or absorbing the substance to the composite material contained therein.