Abstract: One advantageous embodiment of the invention is a filter device (10) for filtering a fluid and providing three or more substantially continuous directions of flow therethrough. The filter device (10) includes a housing (12) having an entry port (18) and an exit port (20). The housing (12) has a filter medium (22) disposed therein for filtering the fluid that flows along a filtration-flow direction (24a) from the entry port (18) to the exit port (20). The filter medium (22) has a bi-directional valve (28) coupled thereto for selectively directing the fluid along a bypass-flow direction (24b) and a reverse-flow direction (24c) that is generally opposite to said bypass-flow direction (24b). The bypass-flow direction (24b) extends from the entry port (18) to the exit port (20) in bypass of the filter medium (22). Also, the reverse-flow direction (24c) extends from the exit port (20) to the entry port (18).