Patents by Inventor John Wardman Schofield

John Wardman Schofield 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).

  • Measurement of impurity concentration in liquids
    Patent number: 4104585
    Abstract: Apparatus for the measurement of the concentration of impurities in liquids comprising two microwave cavity resonators, means for enabling a standard sample of liquid to be coupled to one of the resonators to affect the resonant frequency thereof, means for enabling a sample of liquid under test to be coupled to the other resonator to affect the resonant frequency thereof, and means for mixing the outputs from the resonators to derive a difference frequency dependent on the difference in concentration of particles in the two samples.
    Type: Grant
    Filed: January 26, 1977
    Date of Patent: August 1, 1978
    Assignee: National Research Development Corporation
    Inventor: John Wardman Schofield