Patents by Inventor Denis John Marshall

Denis John Marshall 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).

  • Underwater welding
    Patent number: 3973712
    Abstract: Underwater welding apparatus including a welding chamber and at least one source of gas under pressure connected to the welding chamber through a demand valve, in which the demand valve allows the flow of gas to the chamber to increase as the increase in the hydrostatic head causes the pressure of the gas in the chamber to increase, and to decrease as the hydrostatic head decreases.
    Type: Grant
    Filed: October 16, 1974
    Date of Patent: August 10, 1976
    Assignee: BOC International Limited
    Inventors: John Richard Carew Armstrong, Denis John Marshall