Patents by Inventor Rudolf Scheidegger

Rudolf Scheidegger 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).

  • Patent number: 4139431
    Abstract: An electrolytic process is used to reduce the silver content of fixer solution to a level such that it can be discharged as effluent. In the process silver is removed from aqueous fixer solutions by circulating the solution in a closed cycle through an electrolytic cell such that the residence time in the cell is not greater than one minute for each passage. The electrode loading is within the range between 5 and 15 mA/cm.sup.2 initially but is reduced in at least one further chronologically consecutive stage. Exhausted developer solution may be added to the fixer solution to act as a pH controlling redox system.
    Type: Grant
    Filed: February 22, 1978
    Date of Patent: February 13, 1979
    Assignee: Ciba-Geigy AG
    Inventors: Rudolf Scheidegger, August Zurrer