Abstract: A filter system includes a fluid-tight housing with filter elements supported in said housing and dividing the interior of the housing into first and second chambers. A pump pumps a liquid under pressure into said first chamber so that the liquid flows from the first chamber through the filter elements into said second chamber. An energy store is located in the housing which stores energy each time the pump is turned on and pressurizes the first chamber. When the pump is turned off and relieves the pressure in the first chamber, the potential energy stored in the energy store is applied as kinetic energy for moving the filter elements and increasing the pressure in the second chamber to cause liquid backflow through the filter elements which deans and rejuvenates the filter elements.