Patents by Inventor Allan F. Norro

Allan F. Norro 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).

  • Method for directly heating concentrated sulfuric acid by electric current flow between surface-passivated electrodes
    Patent number: 4251715
    Abstract: A method is provided for directly heating a concentrated sulphuric-acid solution by passing alternating electric current between surface-passivated electrodes immersed in the solution and by using electrodes of iron or an iron alloy having a low resistance iron or iron alloy inner core covered by an outer high resistance passivating surface layer which are so surface-passivated that the transition resistance between the electrodes and the concentrated sulphuric-acid solution is at least as great as the resistance exerted by the concentrated sulphuric-acid solution.
    Type: Grant
    Filed: December 6, 1977
    Date of Patent: February 17, 1981
    Assignee: Boliden Aktiebolag
    Inventors: Stig A. Petersson, Allan F. Norro