A core sheet includes a primary textured surface and separate secondary cuspations or corrugations. The core sheets are configured for use within a fluid or wastewater treatment unit that typically includes one or more fabric layers. The primary textured surface enhances retention of wastewater fluid received by the unit, which over time causes an increase in build-up of biomatter on the surface, which in turn enhances the efficacy of treatment of the wastewater.

Filter media, such as electret-containing filtration media for filtering gas streams (e.g., air), are described herein. In some embodiments, the filter media may be designed to have desirable properties such as stable filtration efficiency over the lifetime of the filter media, increased normalized gamma, relatively low pressure drop (i.e. resistance), and/or relatively low basis weight. In certain embodiments, the filter media may be a composite of two or more types of fiber layers where each layer may be designed to enhance its function without substantially negatively impacting the performance of another layer of the media. For example, one layer of the media may be designed to have a relatively low basis weight and/or a relatively high air permeability, and another layer of the media may be designed to have stable filtration efficiency and/or a relatively high efficiency throughout the filter media's lifetime. The filter media described herein may be particularly well-suited for applications that involve filtering gas streams (e.g., face masks, cabin air filtration, vacuum filtration, room filtration, furnace filtration, respirator equipment, residential or industrial HVAC filtration, high-efficiency particulate arrestance (HEPA) filters, ultra-low particular air (ULPA) filters, medical equipment), though the media may also be used in other applications.

Filter media, such as electret-containing filtration media for filtering gas streams (e.g., air), are described herein. In some embodiments, the filter media may be designed to have desirable properties such as stable filtration efficiency over the lifetime of the filter media, increased normalized gamma, relatively low pressure drop (i.e. resistance), and/or relatively low basis weight. In certain embodiments, the filter media may be a composite of two or more types of fiber layers where each layer may be designed to enhance its function without substantially negatively impacting the performance of another layer of the media. For example, one layer of the media may be designed to have a relatively low basis weight and/or a relatively high air permeability, and another layer of the media may be designed to have stable filtration efficiency and/or a relatively high efficiency throughout the filter media's lifetime. The filter media described herein may be particularly well-suited for applications that involve filtering gas streams (e.g., face masks, cabin air filtration, vacuum filtration, room filtration, furnace filtration, respirator equipment, residential or industrial HVAC filtration, high-efficiency particulate arrestance (HEPA) filters, ultra-low particular air (ULPA) filters, medical equipment), though the media may also be used in other applications.

A method for manufacturing a filtration media with improved filtration, strength, tear resistance and air permeability in the form of a relatively thin and lightweight wet-laid fibrous web that has a wet Mullen ratio of 20% to 90% to ensure that the media is flexible enough to be formed into a fluted structure, and strong enough to retain the fluted structure when would into a roll and to permit further processing.

A tubular depth filter element has three or more concentric zones. Each zone is made of an essentially continuous melt blown filament. The filament of an outer zone preferably has a larger diameter than the filaments of other zones. The outer zone overlaps with at least 85%, and preferably all, of another zone. Optionally, one or more additional filaments may traverse through all of zones. The depth filter element is made by spraying filaments onto a rotating mandrel to form a filament mass in contact with a conical press roller. The filaments are sprayed from three or more nozzles which are spaced apart along the length of the mandrel. One of the filaments is formed in a spray pattern that is angled towards an adjacent spray pattern so as to overlap with at least 50 or 85%, and preferably all, of the adjacent spray pattern.

Filter media, such as electret-containing filtration media for filtering gas streams (e.g., air), are described herein. In some embodiments, the filter media may be designed to have desirable properties such as stable filtration efficiency over the lifetime of the filter media, increased normalized gamma, relatively low pressure drop (i.e. resistance), and/or relatively low basis weight. In certain embodiments, the filter media may be a composite of two or more types of fiber layers where each layer may be designed to enhance its function without substantially negatively impacting the performance of another layer of the media. For example, one layer of the media may be designed to have a relatively low basis weight and/or a relatively high air permeability, and another layer of the media may be designed to have stable filtration efficiency and/or a relatively high efficiency throughout the filter media's lifetime. The filter media described herein may be particularly well-suited for applications that involve filtering gas streams (e.g., face masks, cabin air filtration, vacuum filtration, room filtration, furnace filtration, respirator equipment, residential or industrial HVAC filtration, high-efficiency particulate arrestance (HEPA) filters, ultra-low particular air (ULPA) filters, medical equipment), though the media may also be used in other applications.

The air filter medium of the present invention is an air filter medium including a stack of a porous polytetrafluoroethylene (PTFE) membrane and an air-permeable support member, a repulsive force generated in the medium when the medium is compressed in a thickness direction thereof is equal to or greater than 30 kPa and equal to or less than 150 kPa at a compression ratio of 30%, and at least one main surface of the air filter medium is formed by the air-permeable support member and has a maximum coefficient of friction of 24 gf or less. The air filter medium of the present invention is an air filter medium that uses a porous PTFE membrane and in which a decrease in collection efficiency due to pleating is inhibited.

Filter media incorporating one or more filtration layers that include fibers including fiber portions orientated at a non-zero angle with respect to a surface of the filtration layer are provided. In some embodiments, at least a part of the fiber portions are positioned at an angle of at least 20 degrees (e.g., between 46 degrees and 90 degrees, or between 61 degrees and 90 degrees) with respect to a surface of the filtration layer or an outer or cover layer of the media. This orientation of fiber portions may result in an increased efficiency (e.g., average efficiency and/or initial efficiency) compared to similar filter media that do not include such oriented fiber portions.

A tubular depth filter element has three or more concentric zones. Each zone is made of an essentially continuous melt blown filament. The filament of an outer zone preferably has a larger diameter than the filaments of other zones. The outer zone overlaps with at least 85%, and preferably all, of another zone. Optionally, one or more additional filaments may traverse through all of zones. The depth filter element is made by spraying filaments onto a rotating mandrel to form a filament mass in contact with a conical press roller. The filaments are sprayed from three or more nozzles which are spaced apart along the length of the mandrel. One of the filaments is formed in a spray pattern that is angled towards an adjacent spray pattern so as to overlap with at least 50 or 85%, and preferably all, of the adjacent spray pattern.

A method for manufacturing a filtration media with improved filtration, strength, tear resistance and air permeability in the form of a relatively thin and lightweight wet-laid fibrous web that has a wet Mullen ratio of 20% to 90% to ensure that the media is flexible enough to be formed into a fluted structure, and strong enough to retain the fluted structure when would into a roll and to permit further processing.