Modular filter assembly

A combination of a filter module unit and a replaceable filter element for a air handling system, the combination comprising.

• the filter module unit having a three sided U-shaped outer frame of channel construction for slidably accepting the filter element within the frame, and a removable access door adapted for positive engagement with the frame for forming a forth side on the frame to enclose the filter element within the frame;
• the filter element being of flat rectangular construction including a filter element frame supporting in peripheral engagement, a filter media, the filter element frame being adapted to tightly fit within the outer frame in such manner as to prevent a directed air stream from diverting around the filter element;
• the U-shaped outer frame comprising a pair of parallel guide legs interconnected by a base leg, each of the legs being three sided in cross section having opposing guide rails integral with an end rail side, the filter element having a mounting surface disposed between four side edges, the edges defining a rectangular peripheral extent of the filter element, the mounting surface adapted to contact three of the opposing guide rails, while two of the four side edges of the filter element are adapted for close fitting, each adjacent to a corresponding end rail side of one of the guide legs such that the filter element is guided between the end rail sides into place against the three of the opposing guide rails, the pair of parallel guide legs being further joined, adjacent to the access door by a support shelf extending between the pair of guide legs and providing a forth surface mainly coplanar with the three of the opposing guide rails to form an open window for exposing the filter media to the directed air stream.