Patents Assigned to N.V. Verto
  • Patent number: 4178157
    Abstract: A method for forming a filter of electrically charged electret fiber material, consisting of a high molecular weight, nonpolar polymeric substance, comprising drawing, charging, and fibrillating a foil of said high molecular weight substance. The fibrillated foil is wound and then crimping is effected.
    Type: Grant
    Filed: December 21, 1977
    Date of Patent: December 11, 1979
    Assignee: N. V. Verto
    Inventors: Jan van Turnhout, Johannes C. Rieke
  • Patent number: 3998916
    Abstract: A method for the manufacture of an electrically charged fibrous filter from a highly molecular non-polar fiber material wherein a web of the fiber material is continuously fed and stretched. At least one side of the stretched web is homopolarly charged by a plurality of corona charging elements. The charged web material is then fibrillated, collected and processed into a filter.
    Type: Grant
    Filed: March 25, 1975
    Date of Patent: December 21, 1976
    Assignee: N.V. Verto
    Inventor: Jan van Turnhout