Abstract: A baghouse filter apparatus including a collapsible bag filter assembly (20) for separating from a gas solid particles entrained therein. The collapsible bag filter assembly comprises a plurality of fabric filter bags (22) extending between a grid sheet (26) and a tube sheet (24) with at least one sheet being movable toward the other sheet and the other sheet being slidably mounted on rails (42). Legs (40) are provided to guide the movement of the one sheet toward the other so as to keep the grid sheet and tube sheet parallel and properly aligned as the bag filter assembly is collapsed. Once the assembly is collapsed, it may be easily slid out of the baghouse (10) through an access opening (30) in the baghouse to facilitate inspection, repair, and bag removal at a location external of the baghouse.