Patents by Inventor Cornelis F. H. Van Egmond

Cornelis F. H. Van Egmond 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).

  • Subterranean heaters
    Patent number: 5065818
    Abstract: An electrical resistance subterranean heater is provided which is cemented directly in a well borehole without a casing in the borehole within the zone to be heated. The absence of the casing results in an economical installation.
    Type: Grant
    Filed: January 7, 1991
    Date of Patent: November 19, 1991
    Assignee: Shell Oil Company
    Inventor: Cornelis F. H. Van Egmond