Abstract: A vortex generator for use in a fluid filter operable in both a normal filtering mode and a back flushing mode. The vortex generator including a flapper valve that moves between an open position and a closed position in correspondence to the direction of fluid flow through the fluid filter. In the open position, fluid is permitted to flow through openings formed in a base of the vortex generator. In the closed position, fluid is prevented from flowing through the openings.