Patents by Inventor Fred W. Prill

Fred W. Prill 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).

  • Asphalt mixer apparatus and method
    Patent number: 4892411
    Abstract: The present invention relates to a continuous drum dryer mixer apparatus and method for heating and drying virgin aggregates, as well as recycled asphaltic pavement materials and mixing such materials with liquid asphalt cement and other ingredients to formulate asphalt paving materials.A first cylindrical rotatable drum dryer has a first material input in one end thereof and a material output at the other end thereof. The output is directable at the option of the operator to either a hot elevator for carrying it to an asphalt batch plant or into a second concentric or offset rotating drum mixer. A burner is mounted either at the output end of the first cylindrical drum, or at the output end of the second drum and extends therethrough to the output end of the first cylindrical drum for directing a flame into the first cylindrical drum.
    Type: Grant
    Filed: February 8, 1988
    Date of Patent: January 9, 1990
    Inventors: E. J. Elliott, Fred W. Prill, Douglas R. Fisher