Patents by Inventor Tage Fridolfsson

Tage Fridolfsson 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).

  • Land drainage system
    Patent number: 4704047
    Abstract: A land drainage system comprising sub-soil tubes (1) connected to a suction container (3) has the container evacuated by a dual function system comprising liquid pumping means (4) and air extracting means (6). A reservoir (5) can contain liquid to be passed into the soil (e.g. for irrigating the land).
    Type: Grant
    Filed: April 23, 1986
    Date of Patent: November 3, 1987
    Assignee: Oy Wartsila AB
    Inventors: Sven Oldfelt, Tage Fridolfsson