a flexible inflatable polymer film filter assembly or device is provided in pouch or sleeve form for filtration of fluid comprising at least one fluid porous dead - end filter panel located internally within the pouch or sleeve with the opposite end edges of the filter panel sealed respectively to first and second polymer film fluid - barrier panels that form the pouch or sleeve so that the respective pouch or sleeve is divided into separate internal chambers , one of which may serve for collection of permeate fluid . the device has a flat two - dimensional form when empty but can assume an inflated three - dimensional form when containing fluid under pressure . the device being constructed of sterilizable thin plastic film , can be cut into transverse segments which can be a segment comprising each filter panel or a segment containing a liquid or non - liquid fluid permeate . the assembly optionally includes a hollow vessel support member for supporting the filter device vertically for gravity flow or forced flow of liquid to be filtered , especially in the laboratory or in the field .