Means for mounting filter units in air ducts

Claim 1

AN AIR FILTERING MECHANISM COMPRISING: (A) A RECTANGULAR CASING INTERPOSED IN AND FORMING A PART OF AN AIR DUCT, SAID CASING HAVING A TOP WALL WITH A FRONT EDGE, A BOTTOM WALL, A PAIR OF SIDE WALLS EXTENDING BETWEEN SAID TOP AND BOTTOM WALLS, AND OPEN FRONT AND BACK WALLS PROVIDING AN AIR INLET AND AN AIR OUTLET; (B) A PLURALITY OF CHANNELED GUIDE RAILS MOUNTED IN SAID CASING PARALLEL TO SAID FRONT EDGE AND EXTENDING FROM ONE OF SAID SIDE WALLS TO THE OTHER, SAID GUIDE RAILS INCLUDING TOP AND BOTTOM CHANNELED GUIDE RAILS AND INTERMEDIATE CHANNELED GUIDE RAILS, SAID TOP GUIDE RAIL HAVING A SUBSTANTIALLY FLAT BASE SECURED TO SAID TOP WALL AND A PAIR OF LEGS CONNECTED TO AND EXTENDING OUTWARDLY FROM SAID BASE TOWARD SAID BOTTOM WALL SO THAT SAID GUIDE RAIL IS OPEN IN THE DIRECTION TOWARD SAID BOTTOM WALL, SAID BOTTOM GUIDE RAIL HAVING A SUBSTANTIALLY FLAT BASE SECURED TO SAID BOTTOM WALL AND A PAIR OF LEGS CONNECTED TO AND EXTENDING OUTWARDLY FROM SAID BASE TOWARD SAID TOP WALL SO THAT SAID GUIDE RAIL IS OPEN IN THE DIRECTION TOWARD SAID TOP WALL, SAID INTERMEDIATE GUIDE RAILS EXTENDING ACROSS SAID CASING MEDIALLY OF SAID OPEN FRONT TO DIVIDE SAID CASING INTO TOP AND BOTTOM COMPARTMENTS AND INCLUDING A PAIR OF CHANNELED GUIDE RAILS EACH HAVING A SUBSTANTIALLY FLAT BASE AND A PAIR OF LEGS CONNECTED TO AND EXTENDING AWAY FRON SAID BASE, SAID BASES OF SAID INTERMEDIATE GUIDE RAILS BEING SECURED TOGETHER IN COEXTENSIVE CONTACT WITH EACH OTHER AND THE LEGS OF ONE OF SAID INTERMEDIATE GUIDE RAILS EXTENDING TOWARD SAID TOP WALL SO THAT SAID GUIDE RAIL IS OPEN IN THE DIRECTION TOWARD SAID TOP WALL, AND THE LEGS OF THE OTHER OF SAID INTERMEIDATE GUIDE RAILS EXTENDING TOWARD SAID BOTTOM WALL SO THAT SAID GUIDE RIAL IS OPEN IN THE DIRECTION TOWARD SAID BOTTOM WALL, AND THE LEGS OF ALL OF SAID GUIDE RAILS TERMINATING IN INTURNED FLANGES, SAID INTURNED FLANGES OF EACH RAIL BEING SPACED APART FROM EACH OTHER TO PROVIDE A LONGITUDINAL OPENING INTO THE RAIL, AT LEAST ONE AIR SEALING STRIP DISPOSED COMPLETELY WITHIN EACH OF SAID CHANNELED GUIDE RAILS AND SECURED BETWEEN THE BASE AND ONE OF THE INTURNED FLANGES THEREOF; (C) A PLURALITY OF AIR FILTER UNITS OF RECTANGULAR FORMATION WITHIN EACH OF SAID COMPARTMENTS, SAID UNITS EACH HAVING A FRAME AND FILTER MATERIAL SECURED IN THE FRAME, EACH FRAME INCLUDING A MOUNTING RIB SECURED TO ITS TOP AND BOTTOM EDGES AND EXTENDING THE FULL WIDTH THEREOF, EACH MOUNTING RIB HAVING A GENERALLY RECTANGULAR PERIPHERAL CROSS-SECTION AND BEING SLIDABLY RECEIVED WITHIN THE LONGITUDINAL OPENING OF ONE OF SAID GUIDE RAILS IN SEALING ENGAGEMENT WITH THE SEALING STRIP LOCATED THEREIN; (D) ONE OF SAID SIDE WALLS OF SAID CASING HAVING AN OPENING IN ALIGNMENT WITH SAID GUIDE RAILS THROUGH WHICH SAID FILTER UNITS MAY BE REMOVED FROM SAID CASING; AND (E) A REMOVABLE CLOSURE FOR SAID LAST-MENTIONED OPENING.