Patents by Inventor Leif Berquist

Leif Berquist 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 for re-insulating installed steam pipe in situ
    Patent number: 6026861
    Abstract: A method and apparatus for re-insulating underground steam pipe in situ includes the steps of creating at least one hole in the ground, inserting a liner into the hole, using a drill string to drill a hole in the conduit, inserting a tubing into the liner so that a first end of the tubing is positioned next to the pipe and a second end of the tubing is attached to a pumping system. The foam is then pumped through the tubing around the pipe and then the tubing is removed and the foam is allowed to cure and become rigid, thereby functioning as insulation.The plastic foam may be a polyisocyanurate or a urethane-modified polyisocyanurate.
    Type: Grant
    Filed: March 30, 1998
    Date of Patent: February 22, 2000
    Assignee: Trigen Energy Corp.
    Inventors: H Timothy Mentzer, Leif Berquist
  • Method for re-insulating intalled steam pipe insitu
    Patent number: 5732742
    Abstract: A method and apparatus for re-insulating underground steam pipe in situ includes the steps of creating at least one hole in the ground, inserting a liner into the hole, using a drill string to drill a hole in the conduit, inserting a tubing into the liner so that a first end of the tubing is positioned next to the pipe and a second end of the tubing is attached to a pumping system. The foam is then pumped through the tubing around the pipe and then the tubing is removed and the foam is allowed to cure and become rigid, thereby functioning as insulation.The plastic foam may be a polyisocyanurate or a urethane-modified polyisocyanurate.
    Type: Grant
    Filed: July 1, 1996
    Date of Patent: March 31, 1998
    Assignee: Trigen Energy Corporation
    Inventors: H. Timothy Mentzer, Leif Berquist