Air filtration cassette with electrostatic precipitator and having multiple filter elements

Claim 1

An air-filtration cassette designed to be inserted and removed from an air-flow duct as a unit, the air-flow duct supporting said cassette when in place in the duct, said air-filtration cassette comprising: a metallic supporting framework having two side walls and one bottom wall joined together into a U-shaped profile, a flange extending along the front and back perimeters of the U-shaped profile, both side walls having a shorter width at the open end of the U-shaped profile than at the bottom end, the bottom part of the two side walls and the bottom wall thereby forming an upstream and a downstream carrier tray; at least one electrostatic ionizer and collector cell mounted within a frame and fastened to the front and back flanges of the side walls along this shorter width, in a manner that provides a space between the bottom of the collector cell and the bottom wall of said framework; a pre-filtering element having substantially the same filtering surface as the cross section of said supporting framework, said pre-filtering element being supported on one side of said electrostatic cell by the upstream carrier tray of said supporting framework; a post-filtering element having substantially the same filtering surface as the cross section of said supporting framework, said post-filtering element being supported on the other side of said electrostatic cell by the downstream carrier tray of said supporting framework; and at least a pair of angle guides removably fastened to the top of said electrostatic cell parallel to the sides of said supporting framework at the open end of its U-shaped profile, said angle guides extending over and holding said pre-filtering and post-filtering elements into their respective carrier trays, the entire air-filtration cassette being fastened to and supported by the air-flow duct through said guides.