Patents by Inventor Thomas C. Caldwell

Thomas C. Caldwell 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).

  • Casing seal and blowout preventer tester and test method
    Patent number: 4090395
    Abstract: Method and apparatus are disclosed for testing the pressure integrity of blowout preventers and wellhead casing hanger seals. An annular pressure chamber between the blowout preventer and wellhead casing hanger is formed by closing the blowout preventer on a tubular member having a test plug which seats within and sealingly engages the casing hanger. Pressure sensing means disposed along the length of the tubular member are used to monitor pressure above, below and within the annular chamber. Pressure changes detected by the sensing means are indicative of leakage across the blowout preventer or wellhead casing seal.
    Type: Grant
    Filed: March 28, 1977
    Date of Patent: May 23, 1978
    Assignee: Exxon Production Research Company
    Inventors: William P. Dixon, Thomas C. Caldwell, William T. Ilfrey