A filter includes filter media and defines an inner plenum. The inner plenum has a cross-sectional dimension extending crosswise of the filter. The cross-sectional dimension decreases from adjacent the upstream side toward to downstream wall to a location disposed intermediate the upstream side and the downstream wall. The cross-sectional dimension of the inner plenum increases from adjacent the intermediate location toward the downstream wall.

The present invention relates to a cabin filter unit, and may comprise: a HEPA filter; and carbon block filters placed at the rear end of the HEPA filter, wherein each of the carbon block filters has a structure which has multiple perforations formed and distributed throughout the entire area thereof for the flow of air, and is formed to satisfy the perforation ratio of 30-50% with reference to 07-10, two or more carbon block filters being stacked, and disposed to be in close contact with each other or spaced apart from each other.

A filter holding device includes an opening portion and a filter. The opening portion communicates an inside of the filter holding device with an outside of the filter holding device. The filter includes a first side and a second side. The first side faces the inside of the filter holding device. The second side faces the outside of the filter holding device. The filter has a lower weight density per unit volume at the first side than at the second side. At least a side face of the first side of the filter is covered with an air-impermeable member. The side face is a lateral face of the filter at the first side.

A paint booth filter assembly has a housing defining an interior having a securable lid, a shop vacuum exhaust attachment point, and a device exhaust. The device exhaust is secured within the lid. Secured within the interior of the housing is a plurality of removable air filters, having different levels of filtration.

Intra-nasal filter devices and methods for their manufacture and use are disclosed. An intra-nasal filter device includes: a first stage filter proximate the septum; and a second stage filter comprising a flexible material extending upwardly from the first filter stage filter; wherein the flexible material comprises: an impedance in the range of 0.02 to 0.2 cmH.sub.2O; an effective cross-sectional area in the range of 0.2 to 2 square inches; and a plurality of radially extending geometric structures disposed along an axial length of the second stage.

Air filter device comprising: one or more pleated air filters where the pleated air filters are cylindrical and designed according to the relation Gu=f.sub.hP.sub.r,/(2r.sub.oε.sup.0.25)>0.8; and a motor for rotating the pleated air filters, wherein ρ.sub.r(r.sub.o−r.sub.i)/ρ.sub.s; r.sub.o=outer radius of the cylindrical pleated filter, f.sub.h=height of the cylindrical filter, r.sub.i=inner radius of the cylindrical pleated filter, p.sub.s=distance between two adjacent pleat tops on the inner radius, ε-ASHRAE efficiency.

Air filter device comprising: one or more pleated air filters where the pleated air filters are cylindrical and designed according to the relation Gu=f.sub.hP.sub.r,/(2r.sub.oε.sup.0.25)>0.8; and a motor for rotating the pleated air filters, wherein ρ.sub.r(r.sub.o−r.sub.i)/ρ.sub.s; r.sub.o=outer radius of the cylindrical pleated filter, f.sub.h=height of the cylindrical filter, r.sub.i=inner radius of the cylindrical pleated filter, p.sub.s=distance between two adjacent pleat tops on the inner radius, ε-ASHRAE efficiency.

An air cleaner assembly including a housing, a filter cartridge removably positioned within the inner opening of the housing, wherein the filter cartridge includes a media pack and a sealing member that includes a pinch seal portion spaced from an outer surface of the media pack and positionable within a housing channel of the housing when the filter cartridge is positioned within the inner opening of the housing, and a precleaner assembly positionable between the filter cartridge and the inlet end of the housing, wherein the precleaner includes a base member having a lower edge, and an access cover removably attachable to an inlet end of the housing, wherein the precleaner assembly is sealable within the air cleaner assembly by pressing the lower edge of the base member against a top surface of the sealing member.

An air cleaner assembly including a housing, a filter cartridge removably positioned within the inner opening of the housing, wherein the filter cartridge includes a media pack and a sealing member that includes a pinch seal portion spaced from an outer surface of the media pack and positionable within a housing channel of the housing when the filter cartridge is positioned within the inner opening of the housing, and a precleaner assembly positionable between the filter cartridge and the inlet end of the housing, wherein the precleaner includes a base member having a lower edge, and an access cover removably attachable to an inlet end of the housing, wherein the precleaner assembly is sealable within the air cleaner assembly by pressing the lower edge of the base member against a top surface of the sealing member.

An assembled air cleaner includes an air blowing box, a plurality of first filter boxes that is stacked in a vertical direction and disposed above the air blowing box, and an air inlet box disposed on top of the topmost first filter box. At least one filter is provided inside the first filter boxes. Each first filter box has a bottom wall and a flange protruding upwardly around a peripheral edge of the bottom wall. The flange is configured to hold against a bottom of the filter in an airtight manner. A plurality of airtight members is provided on each first filter box and can be pressed against the filter, thereby improving filtering and dust collection effects greatly.