A filter assembly that includes a filter housing with a housing interlocking feature, a filter cover with a filter cover interlocking feature, and a filter element with a filter element interlocking feature is disclosed. The filter element is positionable within the filter housing, and the filter cover is attachable to a top portion of at least one of the filter element and the filter housing. The housing interlocking feature, the filter cover interlocking feature, and the filter element interlocking feature are interlockable with each other and extend in a nonplanar configuration along at least one side of the filter element when the filter housing, the filter cover, and the filter element are assembled together.

An ambient air purification device has a filter device arranged in a filter receiving region of its housing. The filter device has a main filter element and a prefilter element, each having a circumferential frame device. A clamping force generating device is provided in the housing to exert an axial clamping force on the frame device of the main filter element resting, when mounted, at the frame device of the prefilter element. The clamping force is transmitted to the frame device of the prefilter element and presses the latter seal-tightly via a seal against a circumferential contact shoulder of the filter receiving region to seal the filter device in the filter receiving region. The frame device of the main filter element is sealed indirectly by the frame device of the prefilter element in relation to the housing and has no seal location of its own in relation to the housing.

An ambient air purification device has a filter device arranged in a filter receiving region of its housing. The filter device has a main filter element and a prefilter element, each having a circumferential frame device. A clamping force generating device is provided in the housing to exert an axial clamping force on the frame device of the main filter element resting, when mounted, at the frame device of the prefilter element. The clamping force is transmitted to the frame device of the prefilter element and presses the latter seal-tightly via a seal against a circumferential contact shoulder of the filter receiving region to seal the filter device in the filter receiving region. The frame device of the main filter element is sealed indirectly by the frame device of the prefilter element in relation to the housing and has no seal location of its own in relation to the housing.

The present invention provides a flow grid arranged at a fluid intake side of a fluid flow generating device, the flow grid comprising: a frame configured to be mounted to a housing of the fluid flow generating device; and a fluid flow area connected to the frame, the fluid flow area having an outer perimeter, the outer perimeter having a diameter (d.sub.outer), the outer perimeter being adjacent to the frame, wherein the fluid flow area comprises a polygonal cell arrangement having a kaleidoscopic pattern, wherein the polygonal cell arrangement comprises at least two types of cell geometries sharing a concentric axis, each type of cell geometry being arranged concentrically to the other(s), and wherein the polygonal cell arrangement is convex when viewed from the fluid intake side. There is also provided an ambient air purification device and use of the disclosed flow grid in the ambient air purification device.

The present invention provides a flow grid arranged at a fluid intake side of a fluid flow generating device, the flow grid comprising: a frame configured to be mounted to a housing of the fluid flow generating device; and a fluid flow area connected to the frame, the fluid flow area having an outer perimeter, the outer perimeter having a diameter (d.sub.outer), the outer perimeter being adjacent to the frame, wherein the fluid flow area comprises a polygonal cell arrangement having a kaleidoscopic pattern, wherein the polygonal cell arrangement comprises at least two types of cell geometries sharing a concentric axis, each type of cell geometry being arranged concentrically to the other(s), and wherein the polygonal cell arrangement is convex when viewed from the fluid intake side. There is also provided an ambient air purification device and use of the disclosed flow grid in the ambient air purification device.

A cassette filter for cleaning a fluid includes: a frame; and a plurality of filter elements having a filter medium provided with a folding. The plurality of filter elements are accommodated in a frame such that at least two adjoining filter elements of the plurality of filter elements are arranged at an acute angle to one another and form a V-shaped arrangement. Each of the plurality of filter elements has folded edges which are formed by fold peaks and fold valleys and extend perpendicularly to legs of the acute angle. Each filter element of the plurality of filter elements is provided with foldings such that a height of the respective filter element is smaller at all edge regions than a height in a central region of the respective filter element, and smaller folding surfaces than the central region result at the edge regions.

A filter assembly that includes a filter housing with a housing interlocking feature, a filter cover with a filter cover interlocking feature, and a filter element with a filter element interlocking feature is disclosed. The filter element is positionable within the filter housing, and the filter cover is attachable to a top portion of at least one of the filter element and the filter housing. The housing interlocking feature, the filter cover interlocking feature, and the filter element interlocking feature are interlockable with each other and extend in a nonplanar configuration along at least one side of the filter element when the filter housing, the filter cover, and the filter element are assembled together.

A filter assembly that includes a filter housing with a housing interlocking feature, a filter cover with a filter cover interlocking feature, and a filter element with a filter element interlocking feature is disclosed. The filter element is positionable within the filter housing, and the filter cover is attachable to a top portion of at least one of the filter element and the filter housing. The housing interlocking feature, the filter cover interlocking feature, and the filter element interlocking feature are interlockable with each other and extend in a nonplanar configuration along at least one side of the filter element when the filter housing, the filter cover, and the filter element are assembled together.

An air filter assembly and use thereof for filtration of air in wet or damp conditions, said air filter assembly comprising: an air filter comprising a front frame defining at least one rectangular aperture for receiving an air flow to be filtered; characterized in that said air filter assembly comprises a deflector element extending alongside edge portion of the rectangular aperture and adapted an to deflect an air flow passing through the rectangular aperture away from an adjacent inside surface of the air filter; and a liquid drain arranged such that liquid collected at said adjacent inside surface of the air filter can exit the air filter through said liquid drain.

An apparatus and a method are provided for a heating, ventilation, and air conditioning (HVAC) home air filter to remove airborne molecular contaminants and volatile organic compounds (VOCs) from air within residential spaces. The HVAC home air filter includes a supportive frame having a shape and size suitable to orient the HVAC home air filter within a residential HVAC system. A filter medium is retained within the supportive frame to remove the airborne molecular contaminants and VOCs from air flowing through the residential HVAC system. The filter medium includes a combination of media layers configured to exhibit a relatively high filtration efficiency and a low air pressure drop across the filter medium. The supportive frame includes a plurality of elongate sections and corner sections disposed along perimeter edges of the filter medium to support the filter medium within the residential HVAC system so as direct air through the filter medium.