Fibrous filter medium that includes a surface-loading filter layer comprising fine fibers having an average diameter of less than 1 micron; a depth loading filter layer; and a support layer; wherein the layers are configured and arranged for placement in a gas stream with the surface loading filter layer being the most upstream layer.

The assemblies of the invention can comprise a fine fiber layer having dispersed within the fine fiber layer an active particulate material. Fluid that flows through the assemblies of the invention can have any material dispersed or dissolved in the fluid react with, be absorbed by, or adsorbed onto, the active particulate within the nanofiber layer. The structures of the invention can act simply as reactive, absorptive, or adsorptive layers with no filtration properties, or the structures of the invention can be assembled into filters that can filter particulate from a mobile fluid while simultaneously reacting, absorbing, or adsorbing materials from the mobile fluid.

Filter media including a waved filtration layer are described herein. The filtration layer may be held in a waved configuration by a support layer. In some cases, the filtration layer may have a combination of characteristics (e.g., mean flow pore size, basis weight, amongst others) that can lead to enhanced filtration performance (e.g., reduced air permeability decrease), in particular, in high humidity environments. The filter media may be used to form a variety of filter elements for use in various applications.

Filter media and filters are provided having a fibrous web including first and second dissimilar electret fibers ultrasonically bonded to each other. The first and second electret fibers may be directly bonded to each other without needle punching, which substantially maintains the thickness or loft of the fibrous web of the filter media and filters. Maintaining the thickness or loft of the fibrous web during the bonding process decreases the pressure drop across the filter media and increases its dust holding capacity. Medical grade filters and/or self-supporting (i.e., self-pleatable) air filters are also provided. The medical grade filters and/or self-supporting air filters may include one or more support layers ultrasonically bonded to the fibrous web or fiber layers without needle punching, which maintains the stiffness of the support layers and allows the filter to be produced in a single manufacturing step.

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.

Fibrous filter medium that includes a surface-loading filter layer comprising fine fibers having an average diameter of less than 1 micron; a depth loading filter layer; and a support layer; wherein the layers are configured and arranged for placement in a gas stream with the surface loading filter layer being the most upstream layer.

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.

A filter and filter media configured and arranged for placement in a fuel stream is disclosed. The filter and filter media allow for filtering of liquid fuels, such as diesel fuel. In certain embodiments the filter media includes a media fiber (such as glass) and a binder fiber (such as bicomponent) that combine to create a media structure having low solidity and relatively low compressibility, and which contain a pore structure that avoids premature fouling of the filter by fuel degradation products.

The present invention relates to a filter media for filtering condensate which includes oily contaminant. The present invention also relates to a filter comprising the filter media. The present invention also relates to a filtration machine comprising the filter media.

Some embodiments of the present technology relate to a vent assembly. The vent assembly has a vent housing having a first end and a second end. The vent housing defines a mounting structure and an airflow pathway extending from the mounting structure to the environment external to the vent housing. A plurality of sections of filtration media are arranged in a series along the airflow pathway. The plurality of sections are disposed across the airflow pathway. The plurality of sections of filtration media includes efficiency sections and spacer sections alternating with the efficiency sections within the series. Each spacer section has a flow resistivity up to 80% of a flow resistivity of each efficiency section.