Patents by Inventor David P. DeVries

David P. DeVries 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).

  • Lightweight concrete aggregate and method
    Patent number: 4235640
    Abstract: A lightweight aggregate for use in making concrete which comprises scoria aggregate with the individual particles of the aggregate being impregnated with a slow or medium setting asphalt emulsion in an amount sufficient to materially reduce the absorption rate of the scoria aggregate.
    Type: Grant
    Filed: June 12, 1979
    Date of Patent: November 25, 1980
    Assignee: David P. DeVries
    Inventors: Bruce P. Cox, David P. DeVries