Abstract: A filter media comprises a layer of porous material having a patterned outer surface comprising a plurality of structures. Each structure in the plurality has at least a predetermined height based on an expected contaminant and spacing between each structure in a pair of structures in the plurality is at most a predetermined spacing based on the expected contaminant.

Abstract: Embodiments herein relate to end caps and pleat guides for filter assemblies. In an embodiment, a filter assembly component is included having an end cap that can include a pleat guide channel disposed about a circumference of the end cap. The pleat guide channel can include a repeating pattern that can include a plurality of peaks and a plurality of valleys distributed about the circumference of the end cap. The pleat guide channel can be configured to receive and mechanically support a pleated filter media within the pleat guide channel. Other embodiments are also included herein.

Abstract: A vent assembly having a housing (106) defining a cavity (202), a first end (102) and a second end (104), where the second end includes a coupling structure (108). The first end defines a window (110) in fluid communication with the cavity, wherein the window has a window perimeter. The vent assembly includes a vent media (206) spanning the cavity of the housing, where the vent media is breathable and forms a watertight seal to the housing at a perimeter of the vent media. The first end includes a screen structure (300) within the window perimeter of the window that can include repeating structures defining open areas.

Abstract: A filter assembly has a housing defining an inlet and an outlet. A plurality of chemical filter elements are disposed in the housing and are arranged in a series with respect to fluid flow. A spacing region is between adjacent filter elements in the series. Also disclosed is an assembly having a housing and a first and second chemical filter element. The second chemical filter element is downstream of the first chemical filter element. Each chemical filter element has a sheet of chemical filter material having a first edge and a second edge. A first flow path is defined parallel to a surface of the first sheet extending from its first edge to its second edge. A second flow path is defined parallel to a surface of the second sheet extending from its first edge to its second edge.

Abstract: Filtration media packs, filter elements, and media are disclosed, including media packs having a plurality of layers of single facer media wherein the layers of single facer media include a fluted sheet, a facing sheet, and a plurality of flutes extending between the fluted sheet and the facing sheet, with the fluted sheet and facing sheet formed of multi-layer media can include a polytetrafluoroethylene (PTFE) layer supported by a polymeric scrim layer.

Abstract: A porous polytetrafluoroethylene (PTFE) membrane including a nonwoven web having a microstructure of substantially only microfibrils fused at crossover points, said membrane having a percent balance of orthogonal dimensions that is within 10%.