Patents by Inventor David H. Doehlert

David H. Doehlert 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).

  • Producing fluid fuel from coal
    Patent number: 4159897
    Abstract: In a coal liquefaction system, product B.T.U./hr. can be significantly increased by dividing the coal to be treated into two portions, liquefying one portion, and adding the other portion to the product of the liquefaction process to produce a suspension for use as a fuel. The process is carried out by adding conventionally available equipment to a coal liquefaction plant, and the total plant is far less expensive to build and operate than a conventional liquefaction plant having the same production in terms of product B.T.U./hr.
    Type: Grant
    Filed: October 13, 1977
    Date of Patent: July 3, 1979
    Assignee: Fluid Coal Corporation
    Inventor: David H. Doehlert