Abstract: A filter for separating finely divided solid particles that may be electrically conducting from electrically nonconducting liquids has means for directing the liquid to be filtered in a radial flow pattern through a filter bed of glass beads to which a high-voltage gradient is applied. A central tubular electrode that serves as a conduit for the liquid extends longitudinally through the filter bed within a concentric cylindrical outer electrode spaced between the central electrode and the casing wall of the filter. After filtering until the electrical current through the filter bed exceeds a predetermined maximum, the voltage gradient is discontinued and the filter backflushed by flowing liquid upwardly through the filter at a rate that expands the filter and causes movement of the beads relative to one another and to the cylindrical outer electrode to remove deposited solids from the beads and from the electrode.