Patents by Inventor Walter Franken

Walter Franken 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).

  • Asymmetrical ultrafiltration membrane on the basis of cellulose triacetate
    Patent number: 4253963
    Abstract: An asymmetrical ultrafiltration membrane based on cellulose triacetate, optionally substituted by up to 30% cellulose diacetate, is made wettable without tendency to embrittlement or shrinkage by adding hydrophobic synthetic silicic acid to the casting solution.
    Type: Grant
    Filed: April 10, 1979
    Date of Patent: March 3, 1981
    Assignee: Sartorius GmbH
    Inventors: Walter Franken, Dieter Nussbaumer, Horst Perl, Ludwig Weickhardt