This disclosure describes a filter medium that minimizes the adverse effects of variations in flow rate on filter medium efficiency without a corresponding increase in pressure drop. The filter medium includes a support layer, a continuous fine fiber layer, and an efficiency layer. The continuous fine fiber layer includes a continuous fine fiber that has a diameter of up to 10 micrometers and is located downstream of the efficiency layer.

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.

Air purification devices include an air inlet and outlet, upstream and downstream sections in air flow communication with the air inlet and outlet and a filter removably positioned between the upstream and downstream sections to filter at least pathogens from air being passed through the filter. One or more ultraviolet (UV) illuminating sources may be positioned in at least the upstream section proximate the filter to illuminate at least an upstream surface of the filter with sufficient UV radiation to kill viable pathogens that accumulate on the filter. One or more ozone generating sources may be positioned to generate ozone in sufficient concentrations to kill viable pathogens proximate the device. The UV illuminating sources and ozone generating sources may be positioned to provide a predetermined pressure drop across the sources and air flow pattern proximate the filter, and enable the filter to be removed without handling the sources.

An improved technology for inactivation of viruses, for example the SARS-CoV-2 virus that is causing the Covid-19 pandemic, is described. The technology can include a device that includes a substrate coated in a polymer that is infused with a pathogen inactivating material. In various embodiments, at a given time, a portion of the pathogen inactivating material is exposed to the environment, and the device is configured to periodically or intermittently expose additional pathogen inactivating material to the environment. For example, the polymer can be ablative or sacrificial.

Metal nanoparticle agglomerates may convey biocidal activity to surfaces upon which they are deposited and become adhered, such as various air filtration media. Air filtration media may comprise a plurality of fibers having a plurality of metal nanoparticle agglomerates adhered thereto. The metal nanoparticle agglomerates may comprise a plurality of fused, partially fused, or unfused metal nanoparticles that are associated with one another upon a surface of the plurality of the fibers. Suitable metal nanoparticles for promoting biocidal activity against various pathogens, such as viruses and bacteria, may include copper nanoparticles and/or silver nanoparticles. Masks, inline filters, and air filtration systems may incorporate the air filtration media.

Proposed is a multi-layer filtration system including a metal catalyst filter unit, a carbon filter unit, and an inorganic compound filter unit. The metal catalyst filter unit includes at least one among metals including Ni, Co, Fe, Cu, Cr, Mg, Zn, Ba, Au, Ag, Pd, Pt, Ru, Mn, and Ti, oxides thereof, and mixtures thereof. The carbon filter unit includes at least one of activated carbon or activated carbon fiber. The inorganic compound filter unit includes an inorganic compound capable of adsorbing toxic gas. The multi-layer filtration system has good removal effect for toxic gas. A filter module including the multi-layer filtration system and a gas mask including the multi-layer filtration system are also proposed.

The technology disclosed herein relates to a vent assembly having a vent housing that defines a first airflow pathway, a second airflow pathway, and a third airflow pathway. The first airflow pathway is configured for fluid communication with an interior of an enclosure. The second airflow pathway is configured for fluid communication with the external environment, and the third airflow pathway extends between the first airflow pathway and the second airflow pathway. A membrane is coupled to the vent housing such that the second airflow pathway and the third airflow pathway are in communication through the membrane. Coalescing filter media is disposed within the vent housing such that the third airflow pathway and the first airflow pathway are in communication through the coalescing filter media. The vent assembly defines a spacing region between the coalescing media and the membrane.

A fume extractor system and method for use with a 3D printer includes a system operable in three conditions including: continuously filtering particulates and fumes at high temperatures during a printing process without intentional removal of pressure from the print chamber; continuously filtering particulates at high temperatures during a print process with intentional removal of pressure from the print chamber, to keep noxious gases retained in the print chamber; and purging the print chamber of fumes and mixing in ambient air to cool the fumes to a temperature low enough to allow adsorption of the fumes created by the printer. The system has a first compartment holding a first filter assembly and a second compartment holding a second filter assembly.

A composite media alternative to high pressure drop glass microfiber HEPA media for use in applications where HEPA efficiency with an oily aerosol challenge with low resistance are required. The composite media contains two light filtration layers, one or both of which is charged, and the efficiency of the material can be greatly increased over a single layer containing the same weight of material. The composite media contains a backer layer to provide mechanical support to the filtration layers.

Disclosed here is a composite filter media having at least one nanofiber layer bonded to a substrate layer, the at least one nanofiber layer optionally having a plurality of nanofibers having a geometric mean diameter of less than or equal to 0.5 μm, the at least one nanofiber layer having a thickness of about 1-100 μm.