A filter assembly is disclosed for use in connection with the filtration of products transported via pipelines, including high pressure gas pipelines. The disclosed filter assembly is comprised of a plurality of filter modules, a series of valves, inlet and outlet ports, connective piping, and spool pieces. The filter assembly will temporarily redirect flow from the pipeline, through one or more filter assemblies, and back into the original pipeline a short distance downstream from the original takeout point. If flanged connections are not readily available for a particular section of pipeline, the filter assembly can be connected to virtually any section of pipe through "hot tapping" technology, which allows a valve to be placed on an active and pressurized section of pipeline. The filter assembly of the present invention allows the operator to replace expired filtering members by shifting product flow from one filter module to another, thereby avoiding the need to take the pipeline out of service during filtering operations. The filter assembly may also be mounted on a skid and/or a mobile trailer.