Patents by Inventor Roberta Shafer

Roberta Shafer 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).

  • Flow stability reporting system for a liquid chromatography system
    Patent number: 4905161
    Abstract: There is disclosed herein a system for testing the flow stability of the pumping system for liquid chromatography. The system determines the flow rate and determines the number of revolutions over which the flow rate is to be measured from the flow rate. The system then measures the value of a signal which is related to the flow rate multiple times for each revolution. The maximum value and the minimum value for each revolution is recorded. After the data from the requisite number of revolutions is collected, a calculation is performed which determines the flow stability indicator which is displayed. The calculation takes a multiple of the difference between the maximum of maximums and the minimum of minimums and divides it by the sum of the maximum of maximums and the minimum of minimums.
    Type: Grant
    Filed: January 11, 1988
    Date of Patent: February 27, 1990
    Assignee: Spectra-Physics, Inc.
    Inventors: Les A. Miller, Roberta Shafer