Patents by Inventor Gerrit J. Wunnink

Gerrit J. Wunnink 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).

  • Sand detection
    Patent number: 4240287
    Abstract: A method and apparatus for detecting sand particles in a flowing fluid, for example, the production from a gas or oil well. An acoustic transducer is used to detect the sand particles and the resulting signal is filtered to pass a frequency band of 50 to 500 kiloherz. A pulse height discriminating means and pulse counter is provided for counting the number of pulses that exceed a pre-set amplitude.
    Type: Grant
    Filed: November 2, 1978
    Date of Patent: December 23, 1980
    Assignee: Shell Oil Company
    Inventors: Harm Mast, Jan W. Kraayeveld, Peter B. Vriezen, Gerrit J. Wunnink