Patents by Inventor Walter W. Robertson, Jr.

Walter W. Robertson, Jr. 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 pressure fluid pump
    Patent number: 4382750
    Abstract: A free piston compressor for gases and liquids in which the positive pressure of the incoming fluid holds the piston against the piston rod during the intake stroke. In a specific form, the cylinder head is a plug of larger diameter than the piston which can be unscrewed to permit removal and replacement of the piston for service.
    Type: Grant
    Filed: December 22, 1980
    Date of Patent: May 10, 1983
    Assignee: Hydro-Pac, Inc.
    Inventors: Walter W. Robertson, Walter W. Robertson, Jr.