Patent ID: 9308483
Filing Date: 2016-04-12
CPC Classification: B01D

Claim Text:
1. A filter assembly, comprising: a filter casing for mounting to a mounting frame of a duct, the filter casing having a plurality of inlet apertures, each inlet aperture being associated with a respective filter cell of the casing and being adapted to permit gas to flow through the casing from the inlet apertures; a filter medium provided to each filter cell of the casing to filter for filtering gas flowing through the casing; and a plurality of pre-filters, each pre-filter comprising: a pre-filter casing having an outlet aperture and being adapted to permit gas to flow through the pre-filter casing to the outlet aperture; and a pre-filter medium provided to the pre-filter casing to filter gas flowing through the pre-filter casing, wherein each pre-filter casing is releasably engaged directly with the filter casing so as to fixedly position the outlet aperture of the pre-filter casing, directly or via an interposed sealing gasket, over an inlet aperture of the filter casing, thereby to seal the inlet and outlet apertures together.