Patents by Inventor Anthony Frederick Douglas

Anthony Frederick Douglas 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).

  • Sealants
    Patent number: 4104211
    Abstract: This invention relates to a non-cationic bitumen and rubber in water emulsion sealant for internally sealing leakages in pipes, particularly gas mains. Sealant is applied by pressurizing the sealant into any leaks. The sealant possesses the following particular advantages:(a) Remains in the leaks and is not drawn from the leakage path when the main is placed back into operation.(b) Dried without cracking.(c) Excess sealant can be easily pumped from the pipe.(d) Stability of the emulsion.
    Type: Grant
    Filed: June 18, 1976
    Date of Patent: August 1, 1978
    Assignee: British Gas Corporation
    Inventors: David Edward Keene, Anthony Frederick Douglas