Patents by Inventor Alfred Widmann

Alfred Widmann 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).

  • Isolation of liquid urea from the off-gas of the synthesis of melamine
    Patent number: 4616094
    Abstract: A process for isolating liquid urea and its thermal decomposition products from the off-gas of melamine synthesis, which gas has been freed from melamine by fractional condensation and then been washed with molten urea, wherein the off-gas, containing 2-10 kg of melt per kg of pure gas, is passed at 8-30 m/sec tangentially into the upper part of an axially symmetrical separation zone. As a result of the rotation imparted to the gas/liquid mixture, the two phases are separated from one another, and both pass downward through the separation zone. The gas and liquid are separately taken off at the bottom end of the separation zone. The residence time of the gas mixture in the separation zone is not less than 0.5 second.
    Type: Grant
    Filed: January 5, 1984
    Date of Patent: October 7, 1986
    Assignee: BASF Aktiengesellschaft
    Inventors: Klaus Borho, Dieter Fromm, Ernst-Juergen Schier, Hans H. Schneehage, Alfred Widmann
  • Process for cooling melamine synthesis waste gases
    Patent number: 4138560
    Abstract: Melamine synthesis waste gases are first treated for the removal of melamine by condensation. The waste gases are then treated with urea-containing melts which are cooled indirectly. At least parts of said indirect cooling takes place together with the treatment of the reaction waste gases with the urea-containing melts in a single zone.
    Type: Grant
    Filed: December 27, 1977
    Date of Patent: February 6, 1979
    Assignee: BASF Aktiengesellschaft
    Inventors: Engelbert Hillenbrand, Hermann D. Fromm, Alfred Widmann