Patents by Inventor Frank J. Lorenzen

Frank J. Lorenzen 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).

  • Method and apparatus for controlled pumping of bentonite around a pipe jacked tunnel
    Patent number: 5632575
    Abstract: An apparatus and method for selectively injecting a liquid bentonite slurry around an exterior of a tunnel liner segment which is pressed into a tunnel being concurrently excavated during a pipe jacking installation. The bentonite slurry lubricates the exterior of the tunnel liner reducing the force required to press the tunnel liner into the tunnel. The apparatus allows an operator of the pipe jacking operation to selectively inject bentonite around individual tunnel liner segment or to allow the apparatus to selectively inject bentonite as required by a preset injection pressure threshold value.
    Type: Grant
    Filed: August 30, 1994
    Date of Patent: May 27, 1997
    Inventors: Frank J. Lorenzen, Mark Guterman