Patents by Inventor Graham C. Stevens

Graham C. Stevens has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Charge stabilized electret filter media
    Patent number: 6780226
    Abstract: An electret filter media includes an additive or mixtures thereof that enhance the charge stability of the media. The filter media achieves acceptable alpha values for a range of filtration challenges without significant decay in alpha values over time. Preferred charge additives include fatty acid amides, oleophobic fluorochemical surfactants, and mixtures thereof.
    Type: Grant
    Filed: April 5, 1996
    Date of Patent: August 24, 2004
    Assignee: Hollingsowrth & Vose Company
    Inventors: Norman Lifshutz, Richard E. Gahan, Graham C. Stevens
  • Charge stabilized electret filter media
    Patent number: 5645627
    Abstract: An electret filter media includes an additive or mixtures thereof that enhance the charge stability of the media. The filter media achieves acceptable alpha values for a range of filtration challenges without significant decay in alpha values over time. Preferred charge additives include fatty acid amides, oleophobic fluorochemical surfactants, and mixtures thereof.
    Type: Grant
    Filed: February 28, 1995
    Date of Patent: July 8, 1997
    Assignee: Hollingsworth & Vose Company
    Inventors: Norman Lifshutz, Richard E. Gahan, Graham C. Stevens