A framed air filter that includes air filter media and a frame with four frame portions. At least one corner of the frame is a bonded, non-integral corner at which a reinforcing plate that integrally extends from an elongate downstream flange of a first frame portion of a pair of neighboring frame portions that meet to form the non-integral, bonded corner, is affixed to an inner sidewall of a second frame portion of the pair of neighboring frame portions.

A collapsible filter having a collapsed position and an expanded position includes a filter media layer having generally parallel pleat edges and a side edge perpendicular to the pleat edge. The filter also has a pair of end caps that are disposed at opposite ends of the filter media layer and are generally parallel to the pleat edges. A flexible side seal is attached to both the end caps but is not attached to the filter media layer. In an expanded position, the flexible side seal extends between the end caps and abuts against the side edge of the filter media layer.

A collapsible device for filtering air comprising a base, a fan functionally attached to the base, an air filter releasably attached to the base, and a substantially air impermeable outer sleeve is provided.

A foldable filter frame including a filter media and a rectangular support frame surrounding and secured to the filter media, having opposed side frame elements having a hingable joint formed near the midpoint that allows the support frame and a dirt-capturing surface of the filter media to fold along lateral line from a planar, extended position to a folded position. The joint includes a fold line in a dirtied-side attaching panel, and a cut formed through a base and a clean-side attaching panel, of the side frame elements, and a means for biasing the joint to the planar, extended position. The biasing means is a strip of elastic member, stapled to an inside surface of the clean-side attaching panel in a relaxed state, across the cut formed through the clean-side attaching panel. The frame can have Velcro-type fasteners in the corners to secure the frame in the folded position.

Embodiments of the inventions include a filter frame and an air filter. The air filter has filtration media and a wood fiber-based filter frame securing filtration media. The filter frame having an upstream facing surface. The upstream facing surface having an orientation substantially perpendicular to a direction of air flow through the filter. The filter additionally having a plurality of sides coupled to the upstream facing surface, the plurality of sides having an orientation substantially parallel to the direction of air flow through the filter, the direction of air flow through the filter defining an exterior side of the filter frame; and a folded edge defined between the upstream facing surface and a first side of the plurality of sides, the folded edge having a debossing on the exterior side of the filter frame.

A framed air filter in which at least one portion of the frame is provided by a spiral-wrapped frame piece in which a terminal segment of the spiral-wrapped frame piece serves as a reinforcing strut.

A cooling air filter for an electric motor, includes a filter with a planar shape and minimum dimension so as to cover the area of the slits of a covering casing of a fan for an electric motor for which it is intended; and the filter is housed in a support which is fixed in a steady and removable way on the surface of the casing; the support having a frame-like structure from which at least two arms extend, which are diametrically opposite in the frame-like structure, and which are provided at their end with fixing and gripping means of the arms on the casing itself; the fixing means being configured for the fast detachment from and hooking onto said casing.

A filter cartridge having a filter media with two opposing ends each being occluded by an adhesive edge seal.

A collapsible air filter assembly for a heating and ventilation air conditioner (HVAC) system includes a filter element, and a frame supporting the filter element. The frame includes at least two edges each including a respective spring element configured to be moveable between an open state and a bent state. A compressible air filter assembly for an (HVAC) system includes a filter medium having rounded pleats configured to collapse and rebound in a controlled and repeatable manner between a compressed state and an original uncompressed state. A soft-wrapped filter assembly includes a frame in a box configuration. The frame includes rigid edges and openings to permit airflow. A filter element is encased by the frame. Flexible edge covers mounted on respective edges of the frame to provide an air seal in an HVAC system.

Collapsible filter assembly includes a filter medium element and a frame at least partially surrounding the filter medium element. The frame and filter media element are configured to vary in at least two dimensions by folding or unfolding. In at least on example, the filter medium element is rectangularly pleated or round pleated. Upon removal of the filter assembly from packaging and other restraints, the filter assembly may naturally expand with regard to footprint and volume, with some manual assistance being expected of a typical user in unfolding from an area-reduced configuration to an area-expanded configuration, and from a volumetrically reduced configuration to a volumetrically expanded configuration.