Disposable expandable air filter

A method of making a disposable air filter kit comprising the steps of:

• providing an expandable pleated filter media having a plurality of generally equal size rectangular filter panels with end plates affixed to outer exposed surfaces of the opposite end panels;
• providing a filter frame including a plurality of frame member panels adapted to be stacked in juxtaposed relation with said pleated filter media when in a collapsed condition, said frame member panels having means disposed on free ends thereof for enabling interconnection of said panels to create a rectangular filter frame sized to receive said pleated filter media into said filter frame when expanded so that opposite free end edges on said filter panels engage selected frame member panels to prevent air passage past the free ends of said filter panels;
• and
• providing a plurality of separating fingers adapted to be compactly stacked with said frame members and collapsed pleated filter media into a kit and being cooperative with said frame member panels to enable insertion of said fingers into openings created between adjacent pleats in the expanded filter media to maintain the pleats in stable positions in the assembled air filter.

A disposable air filter assembly comprising, in combination,

• an expandable pleated air filter element having a plurality of interconnected panels of generally equal longitudinal length and transverse width;
• a filter frame made from a generally rectangular corrugated cardboard blank defining a generally planar rectangular central area enabling air passage therethrough, said blank defining laterally opposite longitudinal side panels and transverse end panels disposed coplanar with said central area and being foldable about respective substantially longitudinal and transverse fold lines to positions generally normal to said central panel and positions in juxtaposed relation to said central area, said side and end panels being mutually cooperable when in said positions normal to said central area to form a perimeter wall about and normal to said central area for receiving said filter element in its expanded condition, said filter frame blank being foldable into a compact generally flat rectangular condition having a longitudinal length and transverse width generally similar to the longitudinal length and transverse width of said filter element panels, and
• a filter grill mountable on said filter frame, said filter grill being made from a generally rectangular corrugated cardboard blank defining a generally rectangular planar central area of a size and configuration substantially equal to the size and configuration of said filter frame central area and enabling air to pass therethrough, said filter grill blank further defining laterally opposite longitudinally extending marginal side wall panels and laterally opposite transverse marginal end wall panels foldable from positions coplanar with said central area to positions disposed normal to said central area for mutual cooperation to establish a boundary wall about the periphery of said filter grill central area, said filter grill central area and side wall and end wall panels being foldable into a compact generally flat rectangular condition having a longitudinal length and transverse width generally similar to the longitudinal length and transverse width of said collapsed filter element panels, said filter element, filter frame blank and filter grill blank being foldable into generally flat rectangular compact positions and stackable in juxtaposed relation for insertion into a carton.

A method of making a disposable air filter comprising the steps of:

• providing an expandable pleated filter element having a plurality of generally equal size rectangular filter panels with adjacent panels being interconnected at mutually opposed longitudinal edges and having generally rigid end plates affixed to outer exposed surfaces of end panels;
• providing a filter frame having a generally planar central area and laterally opposed pairs of sidewalls disposed in normal relation to said central area and having mutually interconnected ends so as to establish a continuous wall peripherally of said central area, said central area having one or more openings enabling air to pass therethrough;
• inserting said filter element into said filter frame when expanded so that opposite marginal end edges on said filter panels engage said continuous wall to prevent air passage past the ends of said filter panels;
• providing a filter grill having a planar central area and a peripheral wall disposed normal to said central area, said filter grill being sized to enable said peripheral wall of said filter grill to be disposed in juxtaposed relation to the peripheral wall of the base surface with the filter element interposed between the central areas of said filter frame and filter grill, said filter grill having a plurality of separating fingers formed integral therewith for insertion between adjacent pleats of the expanded filter element;
• attaching the filter grill to the filter frame;
• and
• inserting said separating fingers between pleats of said expanded filter element.