Patents by Inventor Stefan Lipfert

Stefan Lipfert 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).

  • Limit-level sensor and method of determining the undershooting or overshooting of an intended level of liquid in a container
    Patent number: 6578415
    Abstract: A limit-level sensor for measuring level of a liquid has a resistance element which has an electric resistance which suddenly varies a transition temperature which lies above the maximum liquid temperature. The resistance element is first of all heated by electric current. Thereupon, the electric resistance of the resistance element is measured. When the resistance element is covered with liquid, the heat generated by the electric current is led away so that the temperature of the resistance element is less than its transition temperature. If the resistance element is not covered by liquid, this heat is scarcely led away, so that the temperature of the resistance element remains above the transition temperature.
    Type: Grant
    Filed: April 13, 2001
    Date of Patent: June 17, 2003
    Assignee: Mannesman VDO AG
    Inventors: Ralf Schimmel, Stefan Lipfert, Joachim Acht, Werner Wallrafen
  • Limit-level sensor and method of determining the undershooting or overshooting of an intended level of liquid in a container
    Publication number: 20010015100
    Abstract: A limit-level sensor (3) has a resistance element (4) which has an electric resistance which suddenly varies a transition temperature which lies above the maximum liquid temperature. The resistance element (4) is first of all heated by electric current. Thereupon, the electric resistance of the resistance element (4) is measured. When the resistance element (4) is covered with liquid (2), the heat generated by the electric current is led away so that the temperature of the resistance element (4) is less than its transition temperature. If the resistance element (4) is not covered by liquid (2), this heat is scarcely led away, so that the temperature of the resistance element (4) remains above the transition temperature.
    Type: Application
    Filed: April 13, 2001
    Publication date: August 23, 2001
    Applicant: Mannesmann VDO AG
    Inventors: Ralf Schimmel, Stefan Lipfert, Joachim Acht, Werner Wallrafen
  • Limit-level sensor and method of determining the undershooting or overshooting of an intended level of liquid in a container
    Patent number: 6237411
    Abstract: A limit-level sensor for measuring level of a liquid has a resistance element which has an electric resistance which suddenly varies a transition temperature which lies above the maximum liquid temperature. The resistance element is first heated by electric current. Thereupon, the electric resistance of the resistance element is measured. When the resistance element is covered with liquid, the heat generated by the electric current is led away so that the temperature of the resistance element is less than its transition temperature. If the resistance element is not covered by liquid, this heat is scarcely led away, so that the temperature of the resistance element remains above the transition temperature.
    Type: Grant
    Filed: December 11, 1997
    Date of Patent: May 29, 2001
    Assignee: Mannesmann VDO AG
    Inventors: Ralf Schimmel, Stefan Lipfert, Joachim Acht, Werner Wallrafen