An improved filter assembly.

摘要

@ A plurality of individual filters (1) extend in line across a duct (2) for a gas flow and the duct can be located within secondary containment (7). The pressure of gas within the duct is less than external pressure and the filters (1) can be supported by a guideway (9) which extends across the duct between opposing walls of the secondary containment (7) with the interior of the guideway communicating with the secondary containment to provide an inward flow purge. The filters in the line are replaced individually by inserting a replacement filter into the line at one end and retrieving the displaced filter at the opposite end of the line.