Filtration module

Claim 1

A filtration module for use in a ceiling grid of a clean room, comprising: a housing of rectangular horizontal cross-section having a top with an opening therethrough for connection to an air supply and vertically extending side walls each terminating at its lower end in a continuous, inwardly directed horizontal flange adapted to be supported on said ceiling grid; an inner wall adjacent each of said side walls, each said inner wall having an upper, center and lower section, said center section extending in spaced, parallel relation to the corresponding vertical side wall, said lower section having an outwardly stepped portion terminating in an outwardly directed horizontal flange overlying and secured to said horizontal flange of said corresponding side wall, and said upper section terminating in a downwardly projecting flange spaced inwardly from said center section, said housing and said inner walls together comprising an air-tight enclosure between said opening in said top and the opening defined by said downwardly projecting flanges; a removeable filter element having a rectangular peripheral frame and a deformable gasket extending along the entire periphery of said filter element on the upper face thereof, said filter element being receivable within the opening defined by said center sections of said inner walls with said gasket in sealing engagement with said downwardly projecting flange; a rectangular retaining frame adapted to underly the lower face of said peripheral frame of said filter element and said stepped portions of said lower sections of said inner walls; and means releaseably securing said retaining frame to said stepped portions.