A nano silver active filter element comprises a filter element body which comprises sheet filter papers stacked of layered composite structures, the sheet filter papers successively comprises a nano silver antibacterial layer, a filter layer and a protection layer from an air inlet surface to an air outlet surface; the nano silver antimicrobial layer is prepared from phenolic complex fibers loaded with nano silver particles.

Filter media comprising a pre-filter layer and related components, systems, and methods associated therewith are provided. In some embodiments, the pre-filter layer may be designed to impart desirable properties to the filter media, such as a high gamma and/or long service life, while having relatively minimal or no adverse effects on another property of the filter media that is important for a given application. For instance, a pre-filter layer may be used to improve the upstream removal of fine particulate matter, which may clog a downstream efficiency layer comprising submicron fibers and reduce filtration performance. The pre-filter layer may be configured to increase service life and/or increase the gamma of the filter media. Filter media, as described herein, may be particularly well-suited for applications that involve filtering air, though the media may also be used in other applications.

An air filter medium includes a first porous PTFE membrane and a second porous PTFE membrane. The air filter medium (10) 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 thickness of the first porous PTFE membrane is in the range of 4 to 40 μm and a specific surface area of the first porous PTFE membrane is 0.5 m.sup.2/g or less.

Articles and methods involving filter media are generally provided. In certain embodiments, a filter media has a design and/or comprises one or more layers that enhances its efficiency and/or performance.

Filter media including fibers comprising polyvinylidene fluoride (PVDF) and/or a copolymer thereof, are generally described.

A filter holding device includes an opening portion and a filter. The opening portion communicates an inside of the filter holding device with an outside of the filter holding device, and has a rim that extends in a communication direction from the inside of the filter holding device toward the outside of the filter holding device. The filter is disposed in the opening portion, and has a first side and a second side. The first side faces the inside of the filter holding device. The second side faces the outside of the filter holding device. The filter has a larger weight density per unit volume at the second side facing the outside of the filter holding device than at the first side facing the inside of the filter holding device in a state in which the filter is disposed in the opening portion.

A filter system for a closed fluid transfer system with pressure equalization. The filter system includes a filter having a main flow direction for a fluid passing through the filter extending from a fluid inlet surface to a fluid outlet surface, and a filter housing. The filter has a greater or at least equal extension in the main flow direction compared to at least one direction transverse to the main flow direction.

A nanofiber filter includes: a first support having a front surface and a rear surface opposite to the front surface; a first nanofiber filter layer disposed on the rear surface of the first support; a second nanofiber filter layer disposed on a rear surface of the first nanofiber filter layer; a third nanofiber filter layer disposed on a rear surface of the second nanofiber filter layer; and a second support disposed on a rear surface of the third nanofiber filter layer.

The disclosed technology includes an air filter box for filtering particulates from air. The air filter box can include a filter media pack having a filter layer and a plurality of filter media supports configured to support the filter layer. The air filter box can also include a filter housing having an inlet, an outlet, and a plurality of support tabs configured to align and support the filter media pack inside of the filter housing. The filter media pack can be configured to be folded and placed inside of the housing for cooperative engagement with the support tabs. The filter box can be configured to channel a mixture of air and particulates from the inlet, through the filter media pack, and out the outlet to create filtered air.

Thermoplastic bicomponent binder fiber can be combined with other media, fibers and other filtration components to form a thermally bonded filtration media. The filtration media can be used in filter units, such as breather caps. Such filter units can be placed in the stream of a mobile fluid and can remove a particulate and/or fluid mist load from the mobile stream. The unique combination of media fiber, bicomponent binder fiber and other filtration additives and components provide a filtration media having unique properties in filtration applications.