Abstract: A plurality of individual filters extend in line across a duct for a gas flow and the duct can be located within secondary containment. The pressure of gas within the duct is less than external pressure and the filters can be supported by a guideway which extends across the duct between opposing walls of the secondary containment 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.

Abstract: A filter assembly for particle-in-gas filtration comprises ducts leading to a filter housing which is removable from the ducts and is provided with covers to prevent egress of material from the housing during transport. Covers may be also provided for the ducts. The surfaces of the duct cover and housing cover which are exposed to the environment when the housing is removed may be shielded while gas is passed through the assembly to minimize the exposure of the surfaces to the gas passing through the assembly.

Abstract: Apparatus for transfer of toxic and radioactive materials between a work enclosure and a container for storing and transporting the materials. Materials are moved through a "double-cover" in which a port in the enclosure is closed by a first cover and the container is closed by a second cover. During transfer, the covers are connected together and the space between the covers is swept by an air stream to prevent ingress and deposition of toxic or radioactive material on the surfaces thereof which are exposed to the environment on separation of the covers.