A filter assembly for collecting material entrained in a fluid stream includes a filter element having a tubular filter and an end cap providing a flow conduit which extends between first and second conduit openings communicating with the internal void of the tubular filter. A housing for the filter element has inlet and outlet ports for the fluid stream, a housing bowl in which the tubular filter is located, and a housing head which provides at least one of the ports as a docking port for the first conduit opening. The housing head and end cap are arranged such that the end cap is inserted into the housing head, and then rotated relative to the housing head about an axis perpendicular to the axis of the tubular filter and to the axis of the first conduit