Abstract: An improved filter assembly is provided using a bag-type vessel shell and a removable adapter assembly that contains multiple filter cartridges. The invention can be used with both double-open-end filter cartridges and single-open-end filter cartridges. In either case, both ends of the filter cartridges are held in place by individual positioning guides, so as to maintain a perpendicular orientation and seal integrity. In all cases, a knife-edge end seal is provided to be forced into the end surfaces of the filter cartridges. In one embodiment, a compression plate is provided with a single coil spring to force the multiple knife-edge end seals against their respective filter cartridges. In a second embodiment, individual floating end seals are provided at the compression plate to provide good seal integrity regardless of variations in length of the individual filter cartridges.