Filter media mover for plate type filter

In combination with a liquid filtering device comprising a plurality of filter plates which, when placed together, form liquid containers, means for moving said plates together for retaining elongated sheets of flexible filter media between adjacent plates, thereby forming a pair of fluid-tight chambers on opposite sides of each sheet, there being an inlet to one chamber and an outlet to the opposite chamber on the other side of the sheet, and means for separating the plates when the sheets of filter media are contaminated, a sheet extraction and advancing means for the various sheets of filter media adjacent the filtering device comprising:

• a frame;
• an elongated drive roller for each sheet of filter media supported by said frame and extending generally perpendicular to the longitudinal center line of the media, each said drive roller being a crown roll with a slightly greater diameter at its midpoint than at its ends;
• controllable power means for rotating each said drive roller;
• a freely rotatable bar adjacent each said drive roller and a plurality of rotatable pinch wheels mounted on said bar;
• means for urging each said bar towards its adjacent roller when said power means is activated so that said pinch wheels will press against the filter media which is partially wrapped around said roller, thereby causing a frictional force between said roller and said media that is sufficient to advance the media when said power means is activated, said latter means including means for retracting each said bar away from its adjacent roller when filter media is initially installed and said power means is deactivated.