Patents Assigned to N.V. Verto
  • Method for the manufacture of an electret fibrous filter
    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