Patents by Inventor Jack E. Gratteau

Jack E. Gratteau 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).

  • High sensitivity conductivity detector
    Patent number: 4672322
    Abstract: A high sensitivity conductivity detector for ion chromatography includes an isolated fluid cell and a measuring circuit including an operational amplifier having its input connected to the center tap of a transformer. Feedback from the operational amplifier maintains the center tap at virtual ground potential. The excitation voltage for the transformer is supplied by two operational amplifiers. A thermoelectric semiconductor device maintains the temperature of the sample cell at a constant, ambient temperature.
    Type: Grant
    Filed: August 24, 1984
    Date of Patent: June 9, 1987
    Assignee: Milton Roy Company
    Inventors: Jack E. Gratteau, Dennis W. Janzen, Shailesh Atreya