Patents Assigned to Willard A. Sawyer
  • Pipeline plugging apparatus
    Patent number: 4077435
    Abstract: Apparatus for plugging a pipeline may comprise: a tubular body; seal assemblies carried by the body for moving the body through the pipeline in response to fluid flow therethrough and for sealing between the body and pipeline; an internal valve carried by the body for establishing fluid communication between downstream and upstream portions of the pipeline; and a stop device extendable into the pipeline for arresting movement of the body and for operating the internal valve. A method is disclosed for utilizing the apparatus.
    Type: Grant
    Filed: January 19, 1976
    Date of Patent: March 7, 1978
    Assignee: Willard A. Sawyer
    Inventor: Davis A. Van Scoy