The invention relates to a filter arrangement for cleaning an air stream having at least three filter elements, wherein each filter element has a bellows made of pleated filter medium, wherein the filter elements are arranged in series and any two adjacent filter elements are connected to one another by means of a connecting tab. According to the invention, a fold run-out of all end folds of all bellows is oriented in a particular direction, the connecting tabs are of two different embodiments and the different embodiments of the connecting tabs are arranged alternatingly when viewed in a longitudinal direction of the filter arrangement. Not only is a simple installation of the filter elements in a filter holder thus facilitated but also a defined seating of the filter elements in the filter holder is ensured.

A filter unit includes: a frame having an outer shape surrounding an opening through which air flows and having a collection surface and an opposite surface opposite to the collection surface; and a filter member that is disposed in the opening and filters foreign substances included in the flowing air. A folding groove is formed on the opposite surface of the frame. The folding groove is formed at at least two points of the frame so that when an external force is applied from the opposite surface of the frame toward the collection surface, one of a part and another part of the frame divided based on the folding groove relatively rotates toward the other one, and the frame is folded in such a way that a portion of the collection surface approaches another portion of the collection surface.

A filter frame includes a support supporting a filter member, and the support includes a first support and a second support which are rotatably connected. Each of the first and second support includes a body part including a first vertical member, a horizontal member having one end perpendicularly connected to the first vertical member, and a second vertical member connected to the other end of the horizontal member, a cylindrical shaft part connected to the first vertical member, a rotating part connected to the second vertical member to surround a portion of the shaft part, a locking part provided on one of the first vertical member and the shaft part, and an engaging part provided on one of the second vertical member and the rotating part and engaged and fixed to the locking part. The rotating part of the second support is coupled to the shaft part.

A composite filter includes a filter unit including a filter member having filtering parts, at least one filter module arranged in parallel with at least one of the filtering parts, and a bracket supporting the filtering parts disposed adjacent to each other and the filter module so that the filtering parts disposed adjacent to each other are rotatable. The bracket includes a folded portion that is selectively folded according to the relative rotation of the filtering parts, and attachment portions connected to the folded portion with the folded portion interposed therebetween, and attached to the side surfaces of the filtering parts disposed adjacent to each other. The folded portion and the attachment portions are provided integrally and are formed of a flexible material, and the attachment portion extend to the side surface of the filter module adjacent thereto to seal a gap between the filtering part and the filter module.

An air filter assembly includes a filter element having at least one variable dimension, and a frame for engaging and supporting the filter element. The frame may include a plurality of linear segments forming a rectangular configuration, and a plurality of clips for connecting the linear segments together at corners thereof. The linear segments may be L-channel segments, C-channel segments, or may be of other form. Clips may be used for connecting the linear segments together at the corners. The filter element may have a pattern of creases or fold lines to facilitate folding thereof from an expanded configuration to a reduced configuration. A grate may be included for spanning an area bounded by the frame to support the filter element. The grate may have multiple arms and a central hub. An edge treatment may form a seal between the filter element and the frame.

The addition of a medial longitudinal score line (hinge point) along the longitudinal channels of the filter frame allows for thinner media and/or collapsing the frame on itself which will reduce scrap, save space and save tremendously on shipping costs. The additional score line can be a cut score, skip score, crush score or liquid line. The collapsed filter frame expands upon sliding into the channels of the filter frame media holder whereby the filter frame expands and widens to fit the filter assembly.

A refillable air filter system, including: a reusable and collapsible frame; and a disposable filter that is releasably securable within the collapsible frame, wherein the filter is convertible between a storage/collapsed configuration and a functional/expanded configuration.

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.

Filter elements and methods of manufacturing filter elements are provided. Examples of filter elements include a media pack and a frame attached thereto. In one example, the frame includes a side panel that is or includes a foldable portion. The foldable portion is folded away from the media pack and an adhesive is located therebetween during assembly. In other examples, a media support member is provided that includes at least one side support panel that supports a side of the media pack. A portion of the side support member is positioned between adjacent pleat panels of the media pack.

The present disclosure discloses a filter element paper component, including two frames, wherein the two frames are oppositely arranged and are not connected; filter element paper, wherein two ends of the filter element paper are fixedly connected to the corresponding frames respectively, and the two frames separately locate the two ends of the filter paper during mounting; and a separation strip, detachably connected between the two frames to form a complete hollow cavity. The filter paper is folded and arranged in the cavity. The separation strip is pulled to be respectively separated from the two frames, and the two frames arranged at the two ends of the filter element paper are separately pulled to unfold the filter element paper.