Patents by Inventor Philip D. Lindahl

Philip D. Lindahl 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).

  • Labyrinth seal coal injector
    Patent number: 5558473
    Abstract: The labyrinth seal coal injector is a safe, cost-effective means of continuously injecting dry, sized, coal and other mined materials into a pressurized hydraulic pipeline for transport. The injector consists of a rotor or screw rotated by a motor. Coal is compacted in the injector and forms a hydraulic seal against the pressure in the pipeline. A knife valve is used in initiation of the flow of coal into the pipeline.
    Type: Grant
    Filed: August 15, 1994
    Date of Patent: September 24, 1996
    Assignee: Philip D. Lindahl
    Inventor: Philip D. Lindahl