Patents by Inventor Per Birch

Per Birch 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).

  • Apparatus for driving a rotary drum, such as a rotary kiln
    Patent number: 4403952
    Abstract: A substantially horizontal rotating drum mounted on roller pairs which drum is driven via some of the rollers, drive rollers, by means of a hydrostatic motor on each drive roller. In order to avoid problems, e.g., stoppage if the contact between the drum and one or more drive rollers ceases, each hydrostatic motor is part of a separate power circuit further comprising a hydrostatic pump and a squirrel-cage motor constantly ensuring essentially the same peripheral speed for drum and drive roller irrespective of the torque size.
    Type: Grant
    Filed: November 2, 1981
    Date of Patent: September 13, 1983
    Assignee: F. L. Smidth & Co.
    Inventors: Per Birch, Christian Marcussen