Patents by Inventor Lawrence Walker Maas

Lawrence Walker Maas 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: 3932267
    Abstract: A method for producing uninhibited transformer oil is disclosed which includes isolating a petroleum distillate that is primarily naphthenic and aromatic in character, boiling above 400.degree.F, having a viscosity between 50 and 100 SSU at 100.degree.F, and containing sulfur compounds; contacting the distillate with a solvent selective for aromatic hydrocarbons under conditions to produce a raffinate phase containing 15-30%v aromatic hydrocarbons; hydrotreating the raffinate phase to reduce the nitrogen content to at most 25 PPM, to maintain the sulfur content greater than 0.08%w, and to maintain the aromatic hydrocarbon content greater than 15%v. The product is an uninhibited transformer oil, and it can be further improved by regenerative clay treatment and by the addition of certain aromatic hydrocarbon compounds containing two or more six carbon membered fused or unfused rings, at least one of which is a benzene ring.
    Type: Grant
    Filed: September 11, 1974
    Date of Patent: January 13, 1976
    Assignee: Shell Oil Company
    Inventors: Robert William Lewis, Lawrence Walker Maas