Abstract

Conductive filter elements are made by treating nonconductive fibrous materials such as inorganic or organic fibers with resins containing finely divided carbon. The treated fibers are then fabricated into filter elements which are electrically conductive throughout. Strands of roving or yarn which are nonconductive may be joined by twisting together with strands of conductive roving or yarn to give conductivity to the finished multiple strand. Conductive filter elements are also made from extruded fibers which are filled with carbonaceous material during extrusion. These elements permit grounding of static electrical potential which would otherwise accumulate in a nonconductive element. If desired, a controlled low potential direct or alternating electrical charge can be maintained on the filter element to enhance the separation of particles of opposite charge. Particulate filter media, such as that used in filter beds, may also be treated with carbon to form an electrically conductive filter mass.