Patents by Inventor Charles W. Donohue

Charles W. Donohue 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).

  • Patent number: 5469048
    Abstract: A cathodic protection measurement apparatus including a coupon made of similar material as a buried metal pipeline to form an artificial holiday, where the coupon is buried near and electrically connected to the pipeline to receive the same level of cathodic protection current as the pipeline. A test wire is connected to the pipeline and routed to a normally-closed contact switch located at an access point of a test station. The switch is also connected to a coupon wire, which is routed and connected to the coupon to complete the electrical connection. A reference electrode having a measuring surface contacting the soil close to the buried coupon includes an electrode wire provided to the access point. A voltmeter is connected between the switch and the reference electrode wire, and the switch is then opened to electrically isolate the coupon from the pipeline.
    Type: Grant
    Filed: June 13, 1994
    Date of Patent: November 21, 1995
    Assignee: Meridian Oil Inc.
    Inventor: Charles W. Donohue